ENV Energy Conservation by liaoqinmei

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									              ENV-2D02 Energy Conservation - 2006

                               Practical Handout 2

Week 5 - Work on Management and House design Projects. Briefing for those going on Field
          Course 14:00 – 15:00


Week 6 - Steady State Heat Loss Practical [Lab D].(only for those NOT doing house design project)
            - others work on Management Project or House design.

Week 7 - Dynamic Heat Loss Calculations [Lab D] for those doing default and Deregulation
           options (also optional for those doing house design project)

Week 8 – Work on projects

Week 9 - The UEA Heat Pump - a Case Study - whole class

Week 10 – Seminar Presentations for House design or Management Projects

Week 11 – Remaining Seminar Presentations – Poster Presentation of deregulation Projects.



   Information about Practical Write-ups is given on page 1

   A Paper entitled "Energy use in the University" is attached for reference when doing the
    Management Project on UEA

   Three Papers relating to the proposed UEA Heat Pump scheme are attached at Appendix B
N.K. Tovey           ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                         Steady State Loss

Information on Practical Write-ups                                              For groups doing the Management Report and a
        -Does not apply to those doing House Design Project                     practical Write-Up, the practical write-ups must include:-

The following should be noted.                                                  1) the Transport practical with data analysis as indicated
                                                                                   coupled with a review of the Seminar you had in week 3.
Each Group should submit one practical write-up for each                           Guidance has already been given in the previous handout.
member of the group. Typically that will mean three
different practical write-ups. ALL WRITE_UPS from                               2) the Case History of the UEA Heat Pump
members of the GROUP should be collated together.
                                                                                3) Either the practical done in week 5 or that done in week
For those doing the Deregulation project                                           7. (If your group has 4 people in it then both of these
                                                                                   should be included, if your group has 2, then neither of
1) An analysis of the thermal comfort data collected in                            these should be included).
weeks 1 and 2 and also in previous years.
                                                                                Though you are completing different practicals individually,
2) The Transport Practical + associated seminar                                 it will be expected that all members of the groups will have
                                                                                contributed to the component parts during the formal
     Either the Steady State Practical or the Dynamic Heat                      practicals - e.g. different computer runs etc.
     Loss practical. (If your group has 4 people in it then both
     of these should be included, if your group has 2, then
     neither of these should be included).




                                           Domestic Heat Loss Calculations - Part 2 –

(Those doing House Design are exempt from this practical as much of the work in their project duplicates this practical).

Background

In the practical in week , you had experience of manual calculation             The Practical - preliminaries
of the heat loss from a building. It will be appreciated that if studies
are to be done to examine changes in insulation, this could become              There are two options for this practical. You may
tedious and consequently a set of templates and programs have been
written to allow you to examine changes in insulation levels and also           EITHER
to do a cost benefit analysis of your proposed changes. Other                            study 5 different dwelling of different style and age and
information which is available is the energy use per square metre of                     examine improvements in insulation level that could be
floor area - a method to compare one house with another, and also                        made
issues such as the environmental emissions of CO2, SO2 associated               OR
                                                                                         examine how the thermal performance of one particular
with space heating a house.
                                                                                         house has varied over the 50 years since its construction.
Much of the data available for this practical arose from an
                                                                                You should first decide among members of you group which option
Undergraduate Project (C.Watts (1985)) who measured dimensions
                                                                                you are going to take.
of the Gloucester Street House and the bungalow in Mortimer, and
also abstracted data from John Barkham's (a former member of
                                                                                Once you have done that, it is strongly suggested that each person
faculty in ENV) bungalow. Charlie Watts also wrote the original
                                                                                works on a separate house (or particular date if option 2 is chosen).
FORTRAN programme which was used in every year up till 1998.
                                                                                In this way you can use your time effectively. It thus makes sense
In 2000 there was a complete change in the software to enable the
                                                                                to work on adjacent computers so that you can share and compare
data entry to be much easier, however, in common with all other
                                                                                results.
programmes in this course you are warned that using the normal
SAVE, CLOSE, QUIT options from the EXCEL programmes could
cause unpredictable errors. Always use the buttons provided, and
                                                                                The software is accessed from the normal ENERGY ICON and then
DO NOT use cut an paste as you may affect some or all of the
                                                                                you should select the STEADY STATE HEAT LOSS OPTION.
numerous linked formulae.
                                                                                Once you have accessed the Main Steady Sate Heat Loss Page, you
Following the infra structure changes to the network in Autumn
                                                                                can obtain further information about the practical by selection the
2005, there are several issues which might affect the running of the
                                                                                HELP button. The following information will then be displayed.
software. Any issues will be announced in the red box in the front
sheet of the main Spreadsheet
                                                                                To begin a run - select the CONTINUE button on the main menu
                                                                                when the following menu dialog is displayed (Fig. 1).




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N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                         Steady State Loss




Fig. 1. Menu displayed on entry to program

The above is fairly self explanatory, i.e. you use the large left hand
group of options if you have chosen Practical Option 1 or the large
right group of options if you have chosen option 2. However, it is             If you wish you can generate your own file (for instance as part of
worth restating the following                                                  your management project) - e.g. for a building in the University -
                                                                               you could treat BIO as a building with one room per floor. To do
Each time you reload one of the standard 10 files (for either Practical        this you select the option button at the bottom left of the menu box.
Option), the original data file is reloaded with no changes you may
have made in a previous session. If you wish to explore incremental            If you select a standard house, the will ultimately see the following
changes, then you can store the file using the appropriate button              page displayed. If you select either of the bottom two options you
(NOT the NORMAL EXCEL SAVE OPTION) and then reload                             will be prompted for additional information.
this file using the option button at the bottom left.

       This group of programs allows you to study Steady State Heat Losses. There are basically 3 options
       Either [1st Practical Option]
                 You can use the program to investigate changes to insulation standards on 5 different
                 houses/bungalows which are already stored on the computer.
       Or [2nd Practical Option]
                 You can compare the insulation standards of one house but at five different dates in its history.
       Or
                 As part of your UEA Management Project you may wish to analyse data from a particular building or
                 even your own house.


       If you choose the third option, you must have information about the dimensions of the building - i.e. the roof/floor area, wall
       area, window area, and volume before you start data entry. All these values are already stored for the standard house options.

       Generally you can enter data in any cell coloured white, but those coloured yellow or green are locked and will have values
       automatically calculated for you.

       You may change the U-values (or air-exchange rate) and also the room temperature. The annual energy cost is computed for 6
       different modes of heating.

       If you wish to do a Cost Benefit Analysis, You must first FREEZE the current annual running cost to have something with
       which to compare. Thereafter you can change the insulation standard, enter the capital cost and see how long it will take to
       pay back.

       It is IMPORTANT to note that each time you do a change in energy conservation measures, the Cost Benefit Analysis will be
       related to the initial FROZEN value. If you wish to do an incremental cost benefit analysis ( and this will give different
       answers), then you must save the file after each CBA run and then REFREEZE the new annual cost before starting again.

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N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                         Steady State Loss




Fig. 2. Display of various options available.


PROCEDURE                                                                     The effective costs for loft insulation may be taken as
                                                                               Change in thickness                 Cost (£ per square metre)
When you first access the options shown above for a particular                 increase by 50 mm                   £2.00
house you should get a print out of the key insulation values and also         increase by 100 mm                  £4.00
the summary so that you can choose what changes to make. The                   increase by 150 mm                  £6.00
button to be used is clearly labelled in the centre.                           increase by 200 mm                  £8.00
What you do from now on is up to your group. For instance you
could improve the loft insulation, or insert cavity insulation, draft
                                                                              Cavity Insulation
exclusion or double glazing. You should not change the U-values of
the floors for the existing houses
                                                                                  The terrace House in Gloucester Street has solid walls and
                                                                                   therefore cannot have cavity insulation.
In addition, if you think the temperatures are inappropriate you can
change these on a room by room basis.                                             For houses with walls having a U-value around 1.4 Wm-2oC-1
                                                                                   installing cavity insulation will reduce the value to 0.58 Wm-
The effects of changes to U-Values and Temperatures made are                       2oC-1.
automatically stored on the Summary Sheet. The summary sheet
will change each time you make a set of changes so you may wish to                For houses with walls having a U-value around 1.0 Wm-2oC-1
print this Sheet out periodically. If you do a Cost Benefit Analysis               installing cavity insulation will reduce the value to 0.40 Wm-
on each set, then the printout of the Summary Sheet will be uniquely               2oC-1.
identified by a separate Run Number.
                                                                                  For houses with walls having a U-value around 0.6 Wm-2oC-1
The following guidance is given to allow you to make choices.                      installing cavity insulation will reduce the value to 0.20 Wm-
                                                                                   2oC-1.
Loft insulation
                                                                              Cavity Insulation will cost around £500 for a house with a total floor
The approximate U-values are as shown in the table below                      area of less than 100 square metres and about £750 for larger houses.

 Insulation thickness     U - Value       Insulation     U - Value
                          Wm-2oC-1        thickness      Wm-2oC-1             Double Glazing
 none                       1.5 +          150 mm          0.21                  double glazing which will reduce the current U- value to about
                                                                                 2.5-2.85 (see Data Sheets for more precise details sheet) for a
 50 mm                      0.53             200           0.15
 100 mm                     0.29                                                 cost of £500 per m2, (£60 per m2 DIY).

                                                                              Draft Exclusion
                                                                                 draft exclusion done on an existing house is likely to reduce the
                                                                                  air change rate by about 10-15%. The total cost for the whole

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N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                          Steady State Loss
     house would be say £50 (DIY) or £500 (professionally).                     Temperature Changes
     However, if sealed double glazing units are installed, a
     reduction of up to 25% could be achieved. However, the level               You should be realistic in any changes here. Living Rooms are
     of ventilation must not fall below the following values                    normally supposed to be designed for around 210C, and bathrooms
                                                                                should be of similar temperature because of the low clo value of
 Room                                             Minimum Air-                  people in that room.
                                                  exchange Rate
 Bedrooms and Living Rooms                             0.8                      Once you have decided what changes to make you can select the
 Kitchens and bathrooms                               1.25                      View /Enter/Modify button and select a particular floor (e.g. ground,
 separate Toilets                                      1.5                      top-floor etc.) as shown in the example below. Note: cells coloured
 Hallways and passages with access to                  1.0                      yellow are generally locked and fixed (show dark grey below),
 outside                                                                        while cells coloured green are values already entered for this house
                                                                                or represent cell formulae which are locked. You can only change
                                                                                data in the cells coloured white. Please also note that the
                                                                                temperature is shown in RED, and this may be changed if desired.

                Room       Fabric         Area       U - Value     heat Loss Total Heat            Room         Design
                Name     Component        (m2)                       Rate    Loss Rate             Temp-       heat Loss
                                                                             for Room              erature
                                                   (Wm-2degC-       (W oC-1) (W oC-1)               (oC)          (W)
                                                       1)
              Ground Floor
              Room 1 Walls                6.83          0.58             3.96       orientation        solar gain
                      Windows             0.85          2.24             1.90            E      348.5        11.1 W
                                                                                                MJ/m2
              kitchen    Roof                                                                   annual       mean
                                                                                                gain
                         Floor            9.12          1.00             9.12
                                       volume      air change                                    temperatur
                                                   rate                                          e
                         ventilation     21.80          1.20             9.44          24.4         17.0         440

COST BENEFIT ANALYSIS                                                           Menu Page and FREEZE the costs to those after the first measure is
                                                                                complete.
Once you have made a set of changes you can undertake a Cost
Benefit Analysis, by pressing the appropriate button on the master              Option C
sheet. Each time you do this you will be prompted for a short                   If you wish to examine the cost effectiveness of say loft insulation,
description of the changes made, and also the capital cost. Each Run            you can proceed in the normal way (option A). If you now wish to
you make generates a separate sheet labelled Run1, Run2, .... etc,              look at the effect of double glazing alone (without the loft
and covers a range of discount rates and relative changes in the Fuel           insulation), you must reset the changes made to the U-values for
Price:RPI ratio. The results are presented in tabular form for each             insulation to their original values before you proceed with the
of 6 different means of heating. If you wish you may also select                changes arising from the double glazing. [An alternative would be
your own discount rate and Fuel Price : RPI ratio.                              to close the current data file and re-open the standard version which
                                                                                will automatically reset everything back to the starting point].
IMPORTANT: Read next paragraph carefully
The Cost Benefit Analysis requires a reference price, and this is               ACKNOWLEDGEMENTS.
already stored for the 10 standard houses. All changes you make
will use these stored values as the reference when doing the Cost               I should like to acknowledge both of the following who developed
Benefit Analysis.                                                               the main parts of the to programs as part of their respective
                                                                                Undergraduate Programs. Subsequent developments have provided
There are basically three separate ways in which you can proceed.               the menu interfaces for the programs and in February 2000, the
For your write-up you will certainly have to choose Option C                    software was converted to run under EXCEL..
initially, and you may wish to explore the other options also.
                                                                                Mr J.C. WATTS developed the basic part of the STEADY STATE
Option A                                                                        HEAT LOSS PROGRAM as part of his Undergraduate Project
 Thus you might look at the effects of double glazing and                      (1985-6).
    complete a run like that
 Then you might add on loft insulation improvements, and in                    CHEUNG Chun-ming developed the basic part of the DYNAMIC
    this case everything is referred to the original state. Thus the            HEAT LOSS PROGRAM as part of his Undergraduate Project
    CBA refers to BOTH measures, and the Capital cost entered                   (1985-6). For any students taking the Geophysical Modelling
    should reflect this.                                                        Option, and extension to this work would form a good project for
 If you then add - say cavity insulation, the analysis will                    that Course.
    examine the combined effect of all measures, and the capital
    cost muss, once again be the TOTAL cost of all.                             ADDITIONAL NOTES              for using this program for the
                                                                                Management Project
Option B
In some circumstances you may wish to do on measure separately                  You may use this program to do analysis on the University, but you
and then explore to see if a second measure is cost effective once the          will have to enter key dimension for the relevant buildings. It is
first is complete. In this case you should return to the Main Master            suggested that you treat each building as a one-roomed building.
                                                                                Make sure you have the relevant data before you start.
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N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                          Steady State Loss


For the case of the windows, you will be asked for orientation. Here           The write up should cover issues such as a comparison between the
you will have to use your judgement, as at present only one                    energy use per given floor area.
orientation per room can be entered.
                                                                               Any proposed improvement should give a pay back in no more than
Details for Write-Up                                                           4 years, and it is possible that in some situations there is little more
                                                                               that can be done in terms of improvement.
If you decide to write up this practical, then you should follow the
following guidelines.                                                          On the summary sheet is calculated the gaseous emissions of critical
                                                                               environmental gases associated with heating the house, and you may
As a minimum you should explore a minimum of 2 separate                        like to comment on these if you are comparing the 5 different
insulation improvements for each of the five houses, and include the           houses. If you are looking at the same house with five dates, the
cost benefit study. If you work efficiently in your group with each            you may wish to include the following information in your
person taking a different house, then it should be possible to do the          discussion.
practical work just in the formal session. You should give
recommendations as to what should be done to reduce energy use.                     from 1951 to 1971, the heating was by coal fired heating
In the marking, credit will be given for effective use of the programs              from 1971 to 1981, it was by an inefficient gas boiler with an
to explore the full range of strategies.                                             efficiency of around 60% - not thae 70% now available so
                                                                                     estimates of Gross Energy, Primary Energy, and Gaseous
If you choose the option to study the house with data from different                 Emmissions will be underestimated by a factor of 7/6..
years, then you should assume that there are in fact five separate                  from 1981 - 1994 the boiler was a standard gas one,
houses - each of the same size, but currently of different insulation               from 1994 it has been a condensing gas boiler.
standards.


  DYNAMIC HEAT LOSS CALCULATIONS (optional for those doing Low Energy House Design)

Background                                                                     Unlike the previous program, the whole house is treated as a single
                                                                               roomed building where the internal temperature is constant
PLEASE NOTE:                                                                   throughout, and the scope for changing U-values is restricted.
Like the Steady State Heat Loss program, the software for this                 However, as with the STEADY STATE program you should
practical had to be adapted following the revision of the network              experiment with changing the insulation values, and/or internal
infra structure in Autumn 2005. At the time of preparation of                  thermostat setting. In addition you can vary the time the boiler is on.
this handout (5th January 2006), there still needs to be some
checks needed to the final modifications. What for update                      You and your practical group should attempt at least six separate
notifications                                                                  runs to find out what happens for differing situations. Take note of
                                                                               the warnings as some runs may take a minute or so to complete
Consequently, the following are background notes. More details
of the specific use of the software will be given in the practical in          Procedure
Week 7.
                                                                               First decide on a size of house you are going to examine, AND
Introduction                                                                   THEN CONTINUE TO USE THE SAME DIMENSIONS
                                                                               THROUGHOUT a set of runs. After the set is complete you can
In the previous practical the effects of changing insulation levels and        explore other sizes.
their cost-effectiveness was examined. In this practical the problem
of time-switching will be addressed. This program is much more                 If in doubt use the following values which represents a 3 bedroom
sophisticated than the previous one as it examines not only the                detached house.
steady state heat flows but also dynamic heat variation within a
building, how heat is stored in the building, and the consequences                  External Wall Area   -     155 m2
of time-switching. Each component (e.g. walls, roof etc. is split up
                                                                                    Window Area           -    15 m2
into layers 5 mm thick, and the temperature within each layer is
computed for each minute of real time. Consequently there are a                     Floor Area           -     50 m2
very large number of computations to do, and the running of the                     Roof Area            -     50 m2
program may take a little while. It is for this reason that you must                Height               -     5.5 m
carefully plan what you are going to do during the practical. DO
NOT BE ALARMED IF THERE ARE PAUSES OF TWO                                      These are entered after you have selected the consrtuction type
MINUTES OR SO DURING THE EXECUTION.

This practical may be one chosen for write-up for those not doing the          1)    To run the DYNAMIC heat loss program select the ENERGY
House Design. You should ensure that you complete at least those                     ICON in the normal way and then the DYNAMIC HEAT LOSS
topics covered in 10-14. It is likely that you will need to use more                 option from the main menu.
than 3 hours to adequately complete all the investigations.
                                                                               the following page should be displayed.




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N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                   Dynamic Heat Loss




Fig. 3   Dynamic Heat Loss Menu on Entry



2)   The program runs with prompts for information. These are largely self explanatory, but the following notes may be of assistance.




Fig.4    Options which may be selected

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N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                         Dynamic Heat Loss

                                                                              wall type                     3 - cavity wall with insulation
a)   The model assumes all rooms are heated to the same                       roof insulation thickness     0 mm
     temperature, but permits the dynamic heating characteristics of          floor type                    1 - solid floor without carpet
     a house to be studied. The program is designed to be flexible            air-change rate               1.5 air-changes per hour
     so that any size house may be entered.                                   window type                   single glazed
                                                                              construction weight           medium
b)   Unlike the Steady State program, a restricted range of U-
     values is already stored, and you merely have to choose the
                                                                              [Note the program will automatically round the thickness of
     appropriate construction type from a pull down menu.
                                                                              insulation in the loft to the nearest 10mm.]
c)   for the first run of the program, you should choose the
                                                                              3) Now enter the dimensions of the house in the WHITE CELLS -
     following construction types:-
                                                                              the yellow cells are automatically calculated for you




Fig. 5. Data Entry for dimensions.

NOTE the above dimensions are for illustration only - you can enter any reasonable combination you like.

     The program starts by generating an initial temperature profile,         6)   You will be asked to specify the boiler rating. This should be at
     and this is specified by the INITIAL INTERNAL, and INITIAL                    least equal to the design steady state boiler load, and if you time
     EXTERNAL TEMPERATURES. For the purposes of this                               switch, it should be significantly larger to allow for the warm
     practical, initially select 20oC for the thermostat setting. The              up period in the morning. You can experiment with boiler
     external temperature is entered later.                                        ratings say 25%, 50%, and 100% larger than the design load.

4)   In the next stage you are asked for information about the boiler         7)   The program will compute the saving by time switching, and
     control (Fig. 6)                                                              store the results in a file PLOT.CSV which is loaded back into
                                                                                   EXCEL to display the graph.
     a)   First select the number of ON/OFF cycles (see figure
          below)                                                                   The actual analysis is very computationally intensive, and as
     b)   now select the specific ON/OFF times from the slider                     EXCEL is painfully slow with such calculations, the actual
          menus - note the options prevent you from selecting an                   processing is spawned to DOS. However, because of quirk of
          ON time for your second ON/OFF period which is earlier                   Microsoft (blame Bill Gates!), this runs asynchronously, and
          than the previous OFF setting.                                           you must wait until the processing is complete before
     c)   For the initial runs you should select the constant external             attempting to look at the graphs and the summary results.
          temperature option and as you do so the dialog box will
          appear for you to enter the seelcted temperature                    8)   When you have completed one run, you can try other options:-

     NOTE: if you use the time switching mode you should always                   You should as a minimum attempt to investigate the followings
        use a constant external temperature for the initial runs -                 effects of time switching
        otherwise you will have two conflicting issues operating.                 two contrasting houses, one well insulated, the other poorly -
        Only when you have done all other runs should you                          but both of the same dimensions.
        explore the real climatic data option with time switching.                differences with different boiler ratings
                                                                                  differences in time on/off
     However, if you select the BOILER CONSTANTLY ON                              differences with and without weekend off
        option you can select the climatic data file from the start.              one run with the actual climatic data.( data are available for
                                                                                   January 1985).
5)   You can specify for how long you wish the simulation to run
     for (maximum 31 days - representing the hourly climatic data in          You should aim to answer the following questions:-
     January 1985). However, to begin with it is probably best to
     start with runs of a few days.                                           a)    Keeping the construction and insulation the same, how does
                                                                                    the performance vary when there is a boiler with a large rating


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N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                       Dynamic Heat Loss
     (i.e. very much larger than the steady state requirement). What
     will this mean in practice?
b)   Does a well insulated house save more or less when the                 Return to step (1) to rerun program
     heating system is time switched?
c)   What is the difference between time switching once and twice           It is suggested that you work in pairs, and share the above work to
     a day.                                                                 explore as many possibilities as possible.
d)   Are any results you obtain unexpected?, and if so can you
     explain them? How long does it take for the house to warm up           WARNING:         The software is still under development, and a
     when the heating comes on.                                             supplementary sheet may be issued of changes between the time of
e)   Does a carpet make any difference in the energy consumption            writing this handout - 5th JANUARY 2004 and the actual practical.
     or temperature profile during the day?




Fig. 6. Menus for selection of Boiler ON/OFF times




Fig. 7. Selection of Boiler Rating and length of simulation

Write UP of Dynamic heat Loss Practical.                                    real climatic data, but this should be done only after you have
                                                                            completed a satisfactory set of data with constant conditions. In
Your report for this should cover, as a minimum, the effects of time        your write-up you should indicate the extent to which savings are
switching using a constant external temperature. With this you              achieved for each group of settings. However, you should ensure
should explore the effects of changing boiler sizes, length of time         that the house does as least get up to thermostat setting otherwise
switching etc for say a poorly insulated, and also a well insulated         savings will be largely meaningless.
house. You may also wish to examine the effects of running with




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N.K. Tovey           ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                      Heat Pump Practical


                                        The Proposed UEA Heat Pump - A Case Study

Introduction                                                                  Table 1: Variation of COP with temperature - Manufacturer's
                                                                              Data
In 1981 the University considered the installation of heat pumps for
intermittent heating of residences in the summer months. In this                   Plot a graph of COP against mean temperature so that you can
practical we shall investigate several aspects of the project.                     estimate the COP at any temperature
However, to make the data manageable, several simplifying
assumptions are made here.                                                    2)   The frequency of days having a given mean temperature in the
                                                                                   period (average of 1977 - 1981) is as show in Table 2: -
The proposal was to heat all residences from 16 May to 30
September each year by heat pump, and to provide hot water for the                  Ambient                 Mean of           Number of
University by immersion heaters. The boiler house would be shut                    Temperature              Range               Days
down during this period and there would be a saving in oil of 575595
                                                                                      oF                     oC
litres (based on average consumption over previous five years) at
12.18p a litre. The cost of electricity for immersion heaters was                      50 - 52                10.5                1
estimated at about £7,500 (80% at off-peak-rate - 1.5p per kW/hour                     52 - 54                11.7                8
and 20% at full-rate - 3p per kW/hour). In addition there would be a                   54 - 56                12.8                6
saving in electricity amounting to £3,500 (actual figure), arising                     56 - 58                13.9                23
from savings in the boiler house, e.g. fans, pumps, etc. (The average
cost per unit here is 2.5p per kW/hour.)                                               58 - 60                15.0                22
                                                                                        > 60                  15.5                78
Note: These cost figures relate to actual figures in 1981.
                                                                              Table 2 - Temperature Data
Procedure
                                                                                        Because of incidental gains, no heating is required if the
1) Technical data relating to the heat pumps are:-
                                                                                        ambient temperature is above 15.5oC (60oF) and below
Ambient Temperature                0      5          10   13        15                  that there is a demand of 160 kW oC-1. Construct a new
                                                                                        table with 5 columns as follows:-
(oC)
COP                              3.01    3.48   3.90      4.08   4.20


                  Mean         Number          Heat           Energy          COP        Net Heat     Net Energy
                  Temp         of Days        demand         Required                    Demand        Required
                  (oC)                         (kW)            (GJ)                       (kW)           (GJ)




                                              TOTAL                                      TOTAL
                                                             Table 3: Work Sheet

3)    Enter values in columns (1) and (2) from the appropriate                          Finally complete column (7)
columns in Table 2.
                                                                              4)   Sum Total energy requirements in columns (4) and (7).
        Compute the total heat demand and enter value in column (3)
                                                                              5)   If the continual losses from the primary mains amount to 250
        Work out total energy required (Column 4) - watch units.                  kW, estimate the boiler efficiency and the proportion of the
                                                                                   heat supplied for useful purposes i.e. space heating and hot
           Estimate the appropriate values of COP from graph -                    water using the boilers to supply the heat.
           enter in column (5)
                                                                                        Think about this:- you will need the aggregate from
           Calculate net heat demand allowing for COP -->                              column (4), the figure derived from the mains losses, the
           column (6)                                                                   hot water requirement (from the estimate above), and the

                                                                         58
N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                           Heat Pump Practical
          total amount of oil actually used (assuming a calorific              8)   Estimate the saving in primary energy if the primary energy
          value of 40 MJ per litre).                                                ratio of oil is 1.08, and the equivalent primary energy ratio of
                                                                                    electricity is 3.1
6)   Assuming the cost of electricity for the heat pumps is 3p per
     kWhr, and assuming that the scheme has a lifetime of 10 years,            9)   What are the environmental impacts in terms of CO2 and SO2
     examine the financial viability of the project if the capital cost             emissions if the amounts of the gases emitted per MJ of
     was projected as £250 000. Discount tables for 5% and 10%                      delivered energy are as show in the following table.
     are given below. At the time the Government recommended
     discount rate was 10%, currently it is around 6%.
                                                                                                      CO2                        SO2
          To do this you will need to take into account all the costs          gas                   50.6 g                    0.0001 g
          and savings appropriately discounted . (It is suggested that         oil                    77g                        1.3 g
          you use both 5% and 10% discount rates).
                                                                               electricity           191g                       2. 3 g
7)   Estimate the overall saving in monetary terms with this scheme
                                                                               Note: since we know the actual amount of oil used, we do not need
     and examine the cost benefit if the capital cost is £250,000. You
                                                                               to concern ourselves with the boiler efficiency as these factors have
     may assume a lifetime of 10 years, and should adopt the
                                                                               been simplified to present figures in terms of delivered energy rather
     methods used in your first year economics course.
                                                                               than useful energy.
              In any appraisal it is essential to do a sensitivity
                                                                               Documentation relating to the actual scheme is included in reports
               analysis.
                                                                               which have been bound together and entitled "The proposed UEA
              There was a real possibility that we might have
                                                                               heat pump scheme". These reports are being retyped from the
               qualified for an EEC Grant of £25000. How would
                                                                               originals, and it is hoped to provide everyone with a copy.
               this have changed the situation?
              Equally, there is a possibility that we would not get
               the grant, there would be a cost over run of 15%, and           WRITE UP
               the savings would only amount to       500000 litres of
               oil.                                                            UEA Heat Pump - Write Up - Compulsory for those doing the UEA
              Is the project still viable?                                    Management Project and Practical Write-Up option
              Based on this sensitivity analysis, what
               recommendations would you give to the University?               The write-up for this study should include completion of all the
                                                                               elements of the practical period, and also a critique of the set of
                                                                               papers which are attached to this document.

Discount Table for use in Heat Pump Practical


                                            5% Discount                                 10% Discount
                   years          Present Value   Cumulative                   Present value   Cumulative
                                  of £1                                        of £1
                    1                0.952381        0.952381                     0.909091       0.909091
                    2                0.907029        1.859410                     0.826446       1.735537
                    3                0.863838        2.723248                     0.751315       2.486852
                    4                0.822702        3.545950                     0.683013       3.169865
                    5                0.783526        4.329476                     0.620921       3.790786
                    6                0.746215        5.075691                     0.564474       4.355260
                    7                0.710681        5.786372                     0.513158       4.868418
                    8`               0.676839        6.463211                     0.466507       5.334925
                    9                0.644609        7.107820                     0.424097       4.759022
                    10               0.613913        7.721333                     0.385543       6.144565
                    11               0.584679        8.306912                     0.350494       6.495059
                    12               0.556837        8.863249                     0.318631       6.813690
                    13               0.530321        9.393570                     0.289664       7.103354
                    14               0.505068        9.898638                     0.263331       7.366685
                    15               0.481017       10.379655                     0.239392       7.606077
                    16               0.458111       10.837766                     0.217629       7.823706
                    17               0.436296       11.274062                     0.197844       8.021550
                    18               0.415520        11689582                     0.179859       8.201409
                    19               0.395734       12.085316                     0.163508       8.364917
                    20               0.376889       12.462205                     0.148643       8.513560




                                                                          58
N.K. Tovey           ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                              Appendix 1

Appendix A.
                                           REPORT TO UEA FABRIC COMMITTEE

                                                      by N.K. Tovey - October 1979

                                          ENERGY USE WITHIN THE UNIVERSITY
1.        Introduction
                                                                                            Phase 1: A single remote sensing ultrasonic flow meter at
This paper presents several recommendations relating to energy                              a cost of about £l,OOO should be purchased to measure
conservation within the university. There have been made in the                             flow rate in the secondary circuits. This is strapped to the
light of several studies carried out over the past 12 months, the                           pipe and is easily moved from one site to another. During
details of which are summarised in the appendix. Such as studies are                        this stage flow and return temperatures at selected sites
continuing and this report thus contains interim recommendations.                           would be measured for short periods of time by Dr
                                                                                            T.L.Winnington and myself. This phase should be
Throughout the university there is a general dismay at the lack of                          implemented within the next few months.
effort in promoting energy conservation measures particularly in
times of financial crisis. Further there is a general lack of awareness                     Phase 2: General installation of temperature probes to all
of many of the problems. For instance some suggestions have been                            flow and return pipes. These would be connected to a
made based on limited local knowledge. A particular example of this                         portable recorder when under test. This should be
relates to the temperature of hot water within the university. Many                         implemented as soon as possible after Phase 1.
people in ENV have complained that the temperature is excessive
               o                                                                            Phase 3: The linking of all temperature data for recording
(usually > 65 C) and that there would be significant savings if the                         at a central site.
temperature were reduced generally. However, studies show that this
is not the case, and that the excessive temperature in ENV is unique,
                             o                                                    (d)       half-hourly readings of them in University electricity
and that in some areas(~40 c) there could be grounds for increasing
the temperature.                                                                            meters be taken over a 24 period on a representative winter
                                                                                            day to assess the present temporal distribution of
Energy conservation can be divided into three categories:-                                  electricity use, and assess the time of peak demand. This
                                                                                            should be conducted as soon as possible and in any case
(i)       technical improvements to the fabric of the buildings or                          within the next 2-3 weeks.
          the operating system e.g insulation
(ii)      energy management                                                       3.        Recommendation 2(a) will also permit an estimate of hot
(iii)awareness of energy conservation by the general user.                                  water requirements to be made. From this information it
                                                                                            will be possible to determine whether or not it is desirable
All three aspects are important.                                                            to extend the shut down period to several weeks. This
                                                                                            operating procedure is now in use at the University of
2.        Energy Management                                                                 Leeds. During the summer months the boiler efficiency is
                                                                                            very low, and the effective cost of maintaining the primary
There is a general lack of information about energy use within the                          main in operation could be up to twice the figure quoted
university. Excellent records of the boiler performances are kept but                       above.
little information exists relating to the distribution of electricity use,
or the heat losses within the various buildings or by the primary                 During an extended shut down, the hot water could be supplied by
heating main. Such information is urgently needed to assess energy                electric heating. (I understand many areas are already so equipped.)
conservation strategies. Estimates can be made of the theoretical loss            Alternatively remote site gas boilers could be used. There may be an
from the primary main. This is about 0.15 MW representing a cost of               attraction here in that Gas Boards have given preferential tariffs to
about £3OO per week (at a boiler efficiency of 70%). However,                     those consumers whose peak load is in the summer. A third
studies by the building research establishment of similar heating                 alternative would be to utilise a small gas boiler housed in the boiler
systems indicate the theoretical estimates may underestimate the                  house. Being operated at a high load factor, much higher efficiencies
actual loss by factor of 2 or more because of deterioration in the                should be possible than with the present boilers during the summer.
insulation etc.                                                                   This last alternative would, of course, incur the penalty of the
                                                                                  primary main losses, but to a lesser extent.
It is thus recommended that:-
                                                                                  Current summer base load operation amounts to 1.0 TJ per week
(a)       the heat losses from the primary mains be measured during               (~5000 gallons of oil) and costs around £2,000+ per week. Atypical
          July 1980 immediately following the annual shut down                    summer efficiency is 40% and the heat loss from primary main is at
          period. It is possible that a small range flow meter may be             least 0.12 TJ and may be well over 0.2 TJ per week. To provide hot
          required for this test.                                                 water by electricity would cost between £l,2OO and £l,7OO a week
                                                                                  depending on the actual quantity involved and the actual losses from
(b)       electricity meters be installed throughout the university to            the main. The cost using gas would be around £450-£600 per week.
          determine consumption by each spending authority. This                  Potential savings of up to £l,5OO per week would be possible during
          should be done as soon as practical. The cost of this to be             8-10 weeks of the summer.
          recovered by the saving achieved (see paragraph 13) .
                                                                                  It is therefore recommended that:-
(c)       heat monitoring equipment be purchased to enable heat
          flows in secondary circuits to be determined. This should                         as soon as reliable data from the primary main bases is
          be excused in three phases:-                                                      available, that the above analysis be re-evaluated.

                                                                             58
N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                            Appendix 1

An indirect benefit to such an extended shutdown would be the                           and report difficulties and malfunctions on a day to day
improved maintenance of the remainder of the system that would be                       basis. Further they should identify problem areas (i.e. areas
possible.                                                                               which are too hot or too cold) .

                                                                              The University of Leeds has already set up such a committee with
4.         Thermal comfort studies conducted on several hundred               success.
individuals in the University (see Appendix) indicate that, with a few
exceptions, the University is over heated. This conclusion was                The liaison aspect of this committee is of great importance in Energy
reached from results on five separate days in October 1979 and                Management. For instance if the ENV/MAP building is consistently
January 1980. There is scope for reducing the mean temperature by             over temperature as it has been frequently over the past winters, this
          o                                                                   represents an unnecessary loss of about f2OO per week from that
at least l C. This would result in a saving of around £2O,OOO per
                                                                              building alone. Early and regular reporting would substantially
annum.
                                                                              reduce this figure.
It is therefore recommended that:-
                                                                              6.        It is recommended that:-
(a)       immediate steps be taken to reduce the mean temperature
                                                                                        the importance of the establishment of an Energy Manager
                                          o
          of the University by O.5 C. In this action due                                post be recognised in principle, and that steps be taken to
          consideration must be taken of local cold spots which                         establish such a post as soon as possible.
          should receive special attention (see paragraph 15).
                                                                                        (i)        The post should be at the management level and
          The Government is shortly to introduce a Bill to prohibit                                the person should have a knowledge of the
                                                                 o                                 Engineering, Economic, and Management
          the heating of non-residential buildings above l8.8 C.
                                                                                                   aspects of Energy Conservation.
          Compliance with this figure will give further savings. But
          there may be problems associated with this in view of the
                                                                                        (ii)       He/she should act as co-ordinator of the day to
          relatively high University minimum temperature.
                                                                                                   day reports from the Energy Conservation
                                                                                                   Representatives and should take steps to
It is further recommended that:-
                                                                                                   promote further savings of a management nature.
(b)       after a month of operation with these lower temperatures,
                                                                                        (iii)He/she should evaluate further technical innovations
          further thermal comfort studies be conducted when scope
                                                                                                                     for energy conservation, and
          for a second reduction may become evident.
                                                                                                  regularly report to the Energy Action
                                                                                                  Committee.
(c)       consideration be given to setting the University minimum
                             o
          temperature at l7.5 C.                                              The present investigations indicate that savings of at least £25,000
                                                                              per annum are possible from improved management of heating
5.        Existing Conservation Measures                                      alone. However, the full potential can only be realised if a person
                                                                              can devote at least half (and preferably all) his/her efforts to energy
Several useful conservation measures have been undertaken by the              conservation. Further savings from better management of electricity
University, but to the general user, the University appears to lack a         would be possible and this post would thus be self-financing.
coherent policy towards energy conservation. The University does
not publicise or promote energy conservation measures in a way that           7. It is recommended that:-
some Universities do. Recent implied statements suggesting that
some areas of the University will have to experience greater cuts             (a)       the University seek ways to reduce peak hour electricity
than average to accommodate those areas which cannot be cut do not                      demand. Such strategies could include the phasing of the
help when energy consumption is cited as the prime example of an                        lighting of street lights etc. and the switch off of non-
area in the latter category.                                                            essential equipment during the peak hour.

It is recommended that:-                                                      (b)       the University investigate the suitability of the two part
                                                                                        M.D. tariff.
(a)       an Energy Action Committee (or Working Party) be set up
          as soon as possible to co-ordinate measures relating to             This latter tariff is currently 1.76p per unit (+0.57p F.C.S.) day tariff
          energy conservation.                                                +0.74p per unit (+0.57p F.C.A.) between the hours of midnight and
                                                                              07.00. Note: the normal standard tariff is 1.66p per unit (+0.57p
(b)       as an interim measure, this Committee be a sub-committee            F.C.A.) and this means that at least 9.80% of our consumption must
          of Fabric Committee. It should submit regular reports to            be between midnight and 07.00.
          Fabric Committee. In the longer term, the possibility of
          such a committee taking over the responsibility of the              Approximate savings can be judged from the following table.
          direct and indirect aspects of energy use should be
          examined. In this situation, the new committee would                          % Consumption                     saving
          become a sub-committee of the Site Development Board.                         midnight-7.OO                   using two part tariff
                                                                                                                                    £
(c)       membership of the committee include the relevant                                     lO%                                 200
          University Officers, lay members, and Energy                                         15%                               -5500
          Conservation Representatives from each Spending                                       20%                             11000
          Authority and residence unit. Further representatives of the
          Maintenance workforce should be included.                           Table 1. Approximate Savings using a two part Maximum
                                                                              Demand Tariff
(d)       beside the regular committee meetings, the individual
          members should provide a liaison with the general user
                                                                         58
N.K. Tovey           ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                            Appendix 1

8.         It is recommended that:-                                           9.        It is recommended that:-

           close co-operation between the University Officers and the         (a)       a greater feedback of the performance of the heating
           teaching staff and students of ENV 217 [this was the fore-                   system be provided to the boiler men. This will require the
           runner to ENV258 and ENV278 which in turn were fore-                         display of information relating to boiler efficiency and
           runners to ENV2B14 and ENV2B12 which in turn were                            mean temperature in a manner different from present.
           fore-runners of the current ENV-2D02 and ENV-2E02] be
           continued and that data from formal practicals and                           Several alternatives are possible, but one method might
           individual projects be made available to the Energy Action         be:-
           Committee.



          (1)               (2)                 (3)                 (4)                     (5)                  (6)                    (7)
      Consumption      Mean External          Boiler          Effective heat            Estimated            Estimated             Estimated oil
          of oil        Temp (oC)           Efficiency             load                 Efficiency           Effective             consumption
        (gallons)                                                                    (based on col. 2)       heat load                gallons
                                                                                                          (based on col. 2)     from col. 2, 5 & 6)

      Table 2. Suggested data which should be recorded at regular intervals


By comparing columns (1) and (7) a direct assessment of                       (a)       The Energy Action Committee (see paragraph 5) actively
performance can be ascertained and can be used by the boiler men to                     publicise energy conservation measures and inform people
explore other operating procedures to reduce the value in column (1)                    generally of developments and current trends by regular
below that in column (7).                                                               articles in the Newsletter and 'Phoenix'. [Phoenix was the
                                                                                        Undergraduate Newspaper and the predecessor of
During the last two years there have been two occasions when oil                        Concrete].
consumption has increased dramatically and remained at a higher
level than necessary for several weeks. For example the base load             13.        Present arrangements for assessing energy use are far too
was kept higher than necessary for much of 1978. The excess                   remote for the individual user. Further, there is no real incentive for
represented a cost of £400+ per week. Secondly the heat loss rate             energy conservation particularly in electricity consumption where,
increase between 1977 and 1979 was about 2-2.5 times that expected            unlike heating, the University has little direct control. The
from the Sainsbury Centre and Orwell Close. This trend was evident            installation of electricity meters will help (See paragraph 2b) but it is
during most of 1979 (both early and late) and the excess cost                 further recommended that:-
amounts to about £lO,OOO-£l5,OOO in the period January lst-April
3Oth (see Appendix).                                                          (a)       A financial      incentive     be   provided   to     encourage
                                                                                        conservation.
I am pleased to note that the excess base load of 1978 has reverted to
a more acceptable level but it remains to be seen whether or not the          (b)       The University should obtain information from the
excessive heat loss rate occurs during the next few months. If the                      electricity meters during the initial period and then set a
boiler house staff are alerted to these unnecessary increases at an                     target reduction (say 5%) for all users. The magnitude of
early stage steps can be taken to prevent excess oil consumption over                   this reduction should be decided by the Energy Action
a prolonged period. There may be a correlation between the                              Committee, and when imposed, failure to meet that
prolonged illness of Mr Edwards during the above periods and these                      reduction will require that spending authority to pay in full
increases.                                                                              the excess. To promote further reduction, each spending
                                                                                        Authority should be permitted to receive 50% of any extra
10.        It is recommended:-                                                          saving, the remainder being used by the University for
                                                                                        further conservation schemes.
           that during the vacations, the number of residence blocks
           heated be reduced by the temporary movement of some                (c)       During the initial period steps be taken to ensure that
           permanent residents. I understand such a procedure was,                      deliberate over-consumption by certain areas is not done.
           in fact implemented at Horsham during the recent                             This can be achieved as follows: A datum consumption
           vacation. It should be extended to cover all areas.                          level should be set as that in 1979 (or the mean of 1978
                                                                                        and 1979), and that when the first complete year of
11.        It is recommended:-                                                          individual meter readings is available any overall excess
                                                                                        will be proportioned in respect of the actual individual
           the University actively seek Government Energy                               consumption, and that the cost of any such excess be
           Conservation    Grants,     to   implement       technical                   passed to the individual spending Authorities.
           improvements to heating systems (e.g. zone control etc.).
                                                                              (d)       When the recommendation 2(c) phase 3 has been
Awareness by the general user                                                           implemented, a similar scheme be adopted for the heating
                                                                                        of the University.
12.       There is a general lack of appreciation throughout the
University of the most appropriate conservation measures. This                14.       It is recommended that:-
requires an education of the users, and this requires publicity.
                                                                                        The Energy Action Committee explain the effects of the
It is recommended that:-                                                                peak demand, tariff, and encourage spending Authorities
                                                                                        to switch off non-essential equipment regularly during the
                                                                                        peak demand period.
                                                                         58
N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                           Appendix 1

Technical solutions
                                                                               17.        Lighting on winter afternoons constitutes a significant
Many technical aspects have been considered which are too                      electricity consumption.
numerous to discuss here. However, some of the more important
aspects are listed.                                                            It is recommended that:-

15.        There are a few problem areas regarding the heating of              (a) Provision be made for the replacement of many switches in
buildings which have been identified from the thermal comfort                      public areas (e.g. corridors) with ones which automatically
studies. Floor 02 in the Library is a case in question.                            switch off after a few minutes.

It is recommended that:-                                                            Such devices are common in many Universities. The operation
                                                                                    of such switches would only be actuated after normal working
(a)   Localised cold spots within the University be given early                     hours, and during the day time, an override capability would be
      special treatment. Possible strategies here are i) the                        available.
      improvement of draft proofing, ii) the selected provision of
      double qlazing, and iii) the provision of supplementary                       Further isolated dim lights would continue to operate even when
      heating.                                                                      the remaining ones went out.

      When provided, it will be possible to reduce the general                 (b) Investigation be continued to examine whether the lighting level
      temperatures within many buildings permitting significant                    in corridors etc. could be reduced. It would appear that the
      temperatures. The importance of the double glazing of selected               removal of one bulb in three would cause little inconvenience.
      north facing rooms in which people are seated for extended
                                                                               (c) That the positioning and wiring of all light switches be
      Periods of time should not be overlooked. The large expanse                  rationalised to avoid the present confusion which exists. There
      of window area in most rooms has a dramatic effect on the                    are numerous examples of bad organisation in ENV some of
      mean radiant temperature and consequently on individual's                    which (e.g. those for lighting the stair well) present a
      perception of thermal comfort.                                               considerable safety hazard.

      A local firm estimated that the cost of double glazing a typical         18. It is recommended that:-
      room in the teaching wall would be about £3OO. Within the
      ENV/MAP building there are probably about 10 such offices.               Immediate action be taken to replace the insulation on the primary
      To double glaze would thus cost about £3,OOO but as seen                 main where it has completely worn through. The cost of the defects
      earlier, potential savings of £2OO per week or more are                  in the region of the Computing Centre and Library alone amount to
      achievable. Further, of this, at least £lOO per week would be            £200+ per annum.
      associated with double glazing. Thus such a measure would be
      cost effective in about one year.                                        19.     General summary of important recommendations to be
                                                                               implemented as soon as possible.
      Double glazing, such offices would also minimise the use of
      electric fires in those areas when the general heating to the            1.    Immediate installation of electricity meters throughout
      buildings is turned off.                                                       University.

It is further recommended that:-                                               2.    Installation of heat measuring equipment in three phases:
                                                                                     Phase I to be implemented immediately.
(b)   A zone control of temperature be implemented. In this a
      thermostat and motorised valve would control the flow to                 3.    A test of primary main losses in July 1980.
      radiators in several rooms with a similar aspect. In this way the
      problems associated with solar gain can be alleviated.                   4.    The setting up of an Energy Action Committee within the next
                                                                                     few weeks.
(c)   A single override control be provided on the secondary heating
      circuit of the Sainsbury Centre to prevent overheating during            5.    The immediate repair of the insulation defects on the primary
      the day, and to minimise the interactive effects that occur                    main.
      between adjacent units.
                                                                               6.    The general lowering of the internal temperatures (except in
16.        Several buildings are time switched to cut off heat in the                                                                    o   o
                                                                                     one of the two buildings - Library, Shops) by O.5 C (l F)
evening and then to switch on again at a pre-set time to pre-heat the
                                                                                                                           o
building before 09.00. Modern control devices now optimise the                       immediately, followed by a further O.5 C after a month.
pre-heat time, and shut down time. These units are self adapting
units which automatically adjust for the differing pre- heat                   7.    Greater feedback information of the performance of the
requirements each day. Savings of at least 20% are claimed by one                    heating system to be provided to the Boiler House staff.
manufacturer (Honeywell), and at least seven Universities have
installed such a system. In most instances the system has been cost            Implementation of these recommendations 2-7 should lead to a
effective in under two years.                                                  saving of £20,000+ per year. The figure may well be much higher.
                                                                               Implementation of recommendation 1 will have marginal effect in
It is recommended that:-                                                       the first year but should provide savings of 5% or more (£l2,OOO)
                                                                               within two years.
The University request an immediate survey to be done by the
manufacturer of such a unit (cost £lOO) to assess the suitability of           N.K.Tovey                                           October 1979
such control.
                                                                               Retyped from original (June 1992, and annotated with reference to
Based on the findings of the report decisions relating to the                  current Energy Courses in Section 8. in February 1998/ Janurary
desirability of such a unit for UEA can be made.                               2002).
                                                                          58
N.K. Tovey            ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                        Appendix 2




                                                        APPENDIX B

                            PROPOSED UEA HEAT PUMP - October 1981

                                                           CONTENTS

A)      Proposal by Building Services Engineer- (B Mitchell 6th October 1981)

B)      Comments by Prof. K. Bhaskar

C)        Comments by Dr N.K. Tovey



     A. UNIVERSITY PLAIN: SUMMERTIME HEATING - B.
                        Mitchell                                                     It is proposed that the boilerhouse be shut down as early in
                                                                                     the summer as possible, say mid May until at least the end of
1.     Introduction                                                                  September, possibly to mid October.             The principal
                                                                                     requirement is to stop using the boiler house at times when
       A paper was produced in August 1981 giving the broad outline                  boiler house and distribution efficiencies are at their lowest,
       of a scheme to provide heating to residences by means of Heat                 at which time the effective cost of heating by heavy oil is
       Pumps in Summer, enabling the main Boilerhouse to be shut                     greater than by electricity via heat pumps. Another effect of
       down. Since that time, more information has become available                  the prolonged shutdown is to enable maintenance work to be
       and the present report is intended to supersede the former.                   carried out over a longer period with less overtime working
                                                                                     and less disruption to other maintenance services and also to
2.     Details of the Proposal                                                       make boiler house staff available for other duties.

       a) Present arrangement                                                        To allow this closedown to occur and still allow relatively
                                                                                     low grade heat to be available for residences and adequate
       The main boiler house operates the whole year round apart                     hot water services to be provided, it is proposed to provide:
       from a two-week shutdown for maintenance purposes, usually
       early in July. The boilers produce high temperature hot water         i)        Heat pumps connected directly to the secondary heating
       in a closed circuit which passes throughout the site via pipes                         water circuits.
       which are about 50% above ground, exposed but well
       insulated.                                                                              Waveney Terrace I,    200KW
                                                                                               Waveney Terrace II,   200KW
       During summer, the water circulation is maintained mainly to                            Suffolk Terrace II,   200KW
       provide domestic hot water services, heating generally being                            Norfolk Terrace D,    200KW
       turned off during June, July, August and part of September.                             Norfolk Terrace F,    100KW
       Heating is provided during these months on demand only in                               Suffolk Walk,          70KW
       residences and special areas like the Biology Greenhouse. The                           Orwell/Wolfson,       100KW
       residences are particularly important because of the need to
       provide an acceptable venue for conferences during the                ii)   Additional Domestic hot water electric heaters.
       summer vacation, as well as normal term-time conditions for
       students.                                                                                 Chemistry I                    36KW
                                                                                                 Science Building               24KW
       During the Summer shutdown, domestic hot water services are                               Biology                        36KW
       provided in residences and some academic buildings by means                               Library                        24KW
       of standby electric water heaters.                                                        Computing Centre                9KW
                                                                                                 Launderette                    36KW
        These are provided as listed                                                             Registry                       18KW
                                                                                                 Maintenance                    9KW
          Arts I                 University House
          Arts II                Health Centre                                         It is anticipated that the use of heat pumps will within the
          SCVA                   Sports Centre                                     times 7.30 to 8.30am and 5.00 to 11.00pm and would be in use
          Restaurant             Suffolk Walk & Music Centre                       for about 30 days during May and early June and about
          Norfolk Terrace        Waveney Terrace                                   another 30 days during September and early October. There
          Suffolk Terrace        Orwell/Wolfson Close                              may be a few days, cold or wet at other times during the
          Chaplaincy                                                               summer and it is anticipated that heating via heat pumps would
                                                                                   be available for about 75 days per year.
        b)Proposed installation
                                                                        58
N.K. Tovey           ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                        Appendix 2

         Domestic hot water would be provided for the whole                       In order to obtain as much operating experience as possible
     shutdown period, 150 days and electricity consumption could                  without delay, it is considered that heat pumps should be
     be restricted via time clocks to the period 2.00am to 6.00am                 installed and commissioned before the beginning of Summer,
     (night rate tariff) and an afternoon boost 3.00pm to 4pm.                    say early in May. The quoted delivery period is almost six
                                                                                  months, requiring an order to be placed at the beginning of
     c) Heat Pump Details                                                         November. A few weeks are required prior to this in order that
                                                                                  design considerations can be finalised, so it is imperative that a
         The only British Manufacturer of Heat Pumps of the size                  decision to proceed should be given at least by early October.
     proposed is the York Division of Borg-Warner Ltd, Basildon,                  Any significant delay should effectively delay the whole
     Essex and it is proposed to use their AWHP range. It is                      operation until the following year, avoiding a situation where
     proposed to use two sizes of machine for the duties required:                heat pumps may be installed just by the end of summer,
                                                                                  standing untried until the following spring.
          1) 200KW heating duty, model AWH 65.
          2) 100 & 70KW heating duties, model AWH 25.
                                                                            5.    Financial Assessment
         The larger model has been on the market for about three
     years. The first installed being two units on the roof of an                 The project is to be justified by saving resulting from the
     office block in London, Westminster, which has been used for                 boilerhouse shutdown together with such staff savings as may
     both cooling and heating duties. They are housed in an                       be determined.
     acoustic cover which is extremely effective for these noisy
     machines. The smaller model is more recent and performance                   The saving consist of:
     details are not so readily available and one cannot be seen
     running yet.                                                                          a) Fuel oil savings
                                                                                      less b) Electricity costs
     Some performance figures are given for the AWH 65, to                            less c) Maintenance costs of additional equipment
     produce a hot water flow temperature of 45oC (113oF).                            plus d) Reduced maintenance cost of boiler and other plant.

                                                                                  a) Fuel Oil
Ambient air temperature oC 0             5          10        15
                                                                                  During the period May/September 1981, nearly 520.000 litres
Heating capacity kW           183       227         272       300                 of heavy oil were received, at present prices (12.18p per litre)
                                                                                  worth £63.200. This quantity is part of an eleven year low for
Coefficient of Performance    3.01      3.48        2.90      4.08                fuel oil consumption, obtained partly due to better insulation
                                                                                  but mainly be better operating procedures, frequent attention to
Electrical loading kW         60.8      65.3        70.0      73.5                reducing the levels of heating everywhere and by continual
                                                                                  attention being given to energy conservation. Although other
     The machines are large 3441mm by 2661mm by 2388mm high                       measures may subsequently improve on this figure, it is felt to
     and have four large air handling fans and are noisy. They will               be a valid starting point for the present consideration.
     require to be housed in well-designed acoustic houses for the
     proposed locations.
                                                                                 b)     Electricity costs
     d) Locations
                                                                                  1) Heat pumps
         The hear pumps would be located adjacent to the
     appropriate heating plant rooms, usually within sixty feet                   The total heating load is 1140KW and from two-hourly
     distance, with pipes and cables between. A plan has been                     temperature records kept by the boilerhouse staff, air
     prepared marked with these positions. All locations require                  temperatures during the appropriate times can taken to be an
     that particular attention be paid to containing the noise
     generated by the large compressors and fans in the machines.                 average of 48oF. The C.o.P. of the AWH 65 is 3.8 at this
     especially in enclosed locations such as behind Norfolk and                  ambient temperature, the C.o.P of the smaller unit is likely to
     Suffolk Terraces.                                                            be a little worse and an average C.o.P. of 3.65 has been
                                                                                  assumed.     From this, an electrical load of 312KW is
                                                                                  established.
3.   Estimated Costs
                                                                                  The period of operation is 7 hours per day, operating season is
     At this point, it is possible only to estimate costs for the                 about 75 days, electricity costs to the University is approx
     scheme in an approximate manner. A quotation for the                         3p/kWh. An electricity cost of £4914 is arrived at, a slight
     provision of heat pumps has to be obtained from the local                    adjustment to MD may rarely occur, so the approx cost of
     agent and this is to be modified slightly. Approximate costs of              electricity may be quoted at £5000.
     plumbing and electrical connections have been checked. The
     approximate costs are given:                                                 2) Electric HWS heaters.

     a)   Eight heat pumps                          125.000                       The total connected load is 700KW, 4 hours per 24 will be
     b)   Acoustic houses                            50.000                       during the night at a rate of 1.5p per unit approx, 1 hour per
     c)    Installation, Connections                 30.000                       day at 3p per unit, total electricity cost for 150 days is £9,500.
     d)    Other water heaters, HWS                  25.000
     e)    Contingency & Fees                        20.000                       The total electrical running cost of the heat pumps and HWS
                               Total approx costs   250.000                       heaters will be £14,500.

4.   Programme                                                                    3) Boiler house costs.


                                                                       58
N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                             Appendix 2

      The boilers have 15hp fans, there is an oil circulating pump,                      As a very minimum, it can be said that saving in this
      main site circulating water pump heaters and lighting are all in                 direction would completely offset the additional cost of
      use almost continuously. It is estimated that the boiler house                   maintaining the new heat pumps and heaters, additional
      requires an average of 40KW whilst it is in operation and the                    savings being subject to agreement.
      cost of this, almost £4,500 must be deduced from other
      electrical costs of the project.                                                    Bringing together the four items to be considered for
                                                                                       financial assessment of the project, the savings of a-b-c+d
      The net electrical running cost of the project is therefore                      amount to about £53,000 per annum.
      £10,000 per annum.
                                                                               Conclusion
     c) Maintenance Costs
                                                                               The expenditure of £1/4 million on any scheme must be considered
      As part of the assessment of the proposal, a visit has been              with caution and it cannot be denied that there is some element of
      made to the one location where an AWH installation has been              technical risk in the present project. The significant factor about the
      in operation for about a year and the YORK factory at                    project is the novelty of using heat pumps and to use them in
      Basildon has been visited where machines were seen to test               Summer, or at least into Spring and Autumn. it would obviously be
      and manufacture of machines was seen. Operating and                      simpler and more effective to simply shut down the boilers and not
      maintenance literature has been surveyed and it would appear             provide heating at all, just domestic hot water heaters at a quarter of
      that little relative cost of maintenance would be involved. An           the cost. This would affect Conference Trade, the decision has to be
      annual cost averaged over the first 10 years for Heat pumps              made as to the necessity of heating availability and to date, the
      and electric heaters has been estimated at about £6,000 per              answer has been a definite 'yes'.
      annum. As in all other Projects considerations, no allowance
      is made for amortisation of the plant capital cost. A life of 20         In the event of the University proceeding with this project, a formal
      years can be put against the equipment.                                  application for a grant towards the cost of heat pumps is to be
                                                                               submitted. The Energy Technology Support Unit is prepared to
                                                                               consider for 25% aid, such schemes as may be used to demonstrate
d) Boilerhouse Maintenance Cost                                                new energy conservation technology applications. Preliminary
                                                                               correspondence suggest interest by this Department of Energy unit.
        The boilerhouse is manned for 24 hours per day, there being            They need about 3 months in which to make a decision and in view
        4 boilerman and 4 boilermates taking shifts. The gross cost            of the need to make an early decision within the University, not too
        of this for a 5 month period is £32,000.                               much account should be taken of this possiblity of assistance in our
                                                                               decision making.
        With the introduction of a 5 month shutdown, there could be
        a reduction in the number of hours worked by these men. It             This application of heat pumps should not be considered very much
        is for discussion as to how far the reduction can be taken and         further, to close the boilerhouse completely for example. the cost of
        no figures can be quoted until full consultation is conducted,         energy via heat pumps is attractive only to a degree, being better
        but to give an idea, if the eight men reverted to a 5 day week,        than energy from our district heating system in summer, but not in
        normal working hours, which is possibly the greatest                   winter. In the former, despite rigid attention on efficiencies and
        reduction from £32,000 to about £20,000, saving £12,000                reduction in water flow temperatures the system losses are great in
        per annum. It is likely that actual agreed savings may be              proportion to the heating needed by residences only.
        some fraction of this figure, possibly half.
                                                                               Other alternative methods of heating have been briefly considered,
          The boilerhouse staff would not be idle during the                   the most attractive being groups of communal heat store units. Such
        shutdown period. part of the time would fall during the most           systems cannot be seriously considered, mainly due to the
        popular staff holiday period and the remainder of the time             limitations to the electricity supplies.
        could be divided between boilerhouse maintenance and other
        assistance on plant and equipment, routine maintenance and             It having been established that some degree of space heating in
        to some extent enabling outstanding work to be brought up              residences is required between late May and early October, it is
        to date.                                                               considered that the present project for heat pumps should be
                                                                               promoted.



            B. FINANCIAL APPRAISAL OF THE HEAT PUMPS - by Professor K.N. Bhaskar

1.        Introduction                                                         I have not had sufficient time to elicit all the information required for
                                                                               a full analysis and the conclusions below must be regarded as a first
Normal commercial criterion involves performing a DCF appraisal                approximation.
on the cash flows of the project. The information used in this
appraisal involves:                                                            2.        Summary and conclusion

          1. The document entitled "University Plain Summertime                2.1   On the available evidence and bearing in mind the risky nature
          Heating"                                                                   of the project, the conclusion to the financial appraisal is that
                                                                                     at best, the project is likely to be marginal in financial terms
          2. Normal financial criteria used by firms in the evaluation               and at worst produce a loss.
          of energy related projects.
                                                                               2.2   The project is risky since it involves new technology with the
                                                                                     cost over-run problems of prototype/newly designed
                                                                                     equipment. (Many commercial firms have found similar
                                                                          58
N.K. Tovey            ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                             Appendix 2

      problems in related projects). The figures provided do not                       (a) The UGC takes into account any reserves in the
      make any allowance for the maintenance of the heat pumps                         "adjustment" period and in effect deducts this from the
      and water heaters. Commercial experience would run counter                       University recurrent grant. In essence this will mean that the
      to this argument. Risk is also exhibited in this uncertainty                     University has lost £225,000 whereas the heat pump project
      surrounding the 25% grant from Energy Technology, the                            may generate some cash contribution in later years.
      labour savings, and an additional £10,000 that may be spent on
      existing buildings (see 5.2). Moreover the duel savings may                      (b) If the University uses the money to delay the taking of
      not be achieved.                                                                 harsh decisions then the money have been better invested in a
                                                                                       project which would produce a cash contribution in later years.
2.3   Given that such a project is risky and would normally be
      considered risky notwithstanding the points highlighted in 2.2,                  The University must be aware of the competing pressure and
      it would be reasonable to expect such project to earn a                          make a decision based on all the information available.
      minimum real rate of return (as measured in discounted cash
      flow (DCF) terms) of between 15% and 20%.                                  2.9   If UEA considers that the University ought to spend any
                                                                                       surplus cash so that it is not clawed back by the UGC or used
2.4   With long term interest rates in the US approaching 20% the                      to defer difficult decisions, then I believe UEA ought to have
      UK capital markets will be forced to move closer to the US.                      a full list of all possible projects both academic and non-
      The opportunity cost of spending £225,000 will be an interest                    academic and accept those that achieve the greatest return
      of £38,000 (if interest can be earned at 17%). This potential                    (either cost cutting or revenue generating). This should
      income to the University is automatically reflected in the DCF                   include academically-related projects since £225,000 or so
      calculations as is depreciation.                                                 invested in an academic area may produce additional cash
                                                                                       flows of much greater than £58,000 especially if the UGC
2.5   The DCF calculations produce rates of returns as follows:                        because of this academic development regard UEA in a more
                                                                                       favourable light in the future.
      Assumption           Main elements               Rate of return
                                                        (yield/IRR)                    If the University, after considering all available projects,
                                                                                       decides that this project is the best, then I would support this
(a)   Central            No grant                         11%                          project even if it did not meet normal commercial criteria.
                         No labour savings
                         All others information                                  3.    Project life
                         as per original estimate
                                                                                       The life of the project has been assumed as five years. This is
(b)   Pessimistic        As per (a) but fuel savings      -16%                         the University's current long term planning horizon. Several
                         are not fully achieved and                                    firms visited by myself this year regarded five years as a
                         there is a 20% over-run                                       maximum for such an energy-related project. (One of the
                         of capital expenditure                                        problems in anticipating a longer time horizon in the question
                                                                                       of obsolescence and maintenance of technologically advanced
(c)   Optimistic        As per (a) but 25%                       34%                   equipment).
                        Energy grant assumed
                                                                                 4.    Central assumptions
      Note that the terms central, pessimistic and optimistic are
      simply labels. A case could be made for thinking that the                        There are:
      central case is indeed optimistic. In my experience in similar
      exercises in the private sector management have used a more                      (a) The fuel savings hoped to be achieved are actually
      pessimistic scenario on this type of project as their central case               achieved. I have reperformed the numerical calculations and
      assumption.                                                                      they show a saving of £54,802.

2.6   The University will have extremely high demands on any cash                      (b) The capital expenditure is as per scheduled at £225,000.
      over the next few years. Possible uses of spare case include:                    There is not Energy Technology grant.

      (a)   academic developments                                                      (c) No labour savings are achieved.
      (b)   protection and encouragement of research
      (c)   buffer funds during the period of adjustment                               Assumptions (b) and (c) may seem unnecessarily harsh but
      (d)   compensation for loss of office                                            section 4 discusses the validity of the central assumptions and
                                                                                       one of the conclusions of that section is that there are so many
      The principal and interest that can be earned on the proposed                    unknowns that it is probably not unreasonable and
      capital expenditure is more certain. This coupled with the very                  commercially prudent to assume (b) and (c).
      high cash demands of the University would necessitate the
      undertaking of projects only if (a) the return was exceptional             The cash flows are as follows:
      and/or (b) the project has a low risk attached to it.
                                                                                                             1983        1984      1985      1986
2.7   In essence the project is risky and marginal. Only in the most             Capital expenditure in £ -225,000
      optimistic case does it make a high rate return (34%). The                 Fuel savings in £          54,802    54,802      54,802     54.802
      returns of 11% in the central case is not sufficient to justify the
      University undertaking a risky project in a period of case                 The DCF calculations are:
      shortage.                                                                                                @ 15%           @20%
                                                                                 Net present value in £       -13,740        -28,330.2

2.8   These conclusions may be modified if:                                      Yield/IRR                                         10.95%


                                                                            58
N.K. Tovey           ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                            Appendix 2

Conclusion                                                                    6       Pessimistic scenario

                                                                                      A reasonable pessimistic scenario would comprise:
This project would not normally be considered financially
worthwhile.                                                                           (a) Over-run on capital expenditure to £270,000
                                                                                      (b) Fuel savings reduced to £37,010 as per section 5.1
5.    Validity of assumptions
                                                                                      No allowance has been made for an Energy Technology grant
5.1   Fuel savings                                                                    (which may be countered by the additional money to be spent
                                                                                      on CPC2). No labour savings have been allowed. No
      (a) It may be argued that the fuel savings over the next five                   maintenance costs have been included.
      years may be greater than that because of increasing real oil
      prices. However on balance many energy experts would                            The cash flows are:
      predict that any increase in the real price of oil over the five
      year period would be matched by real increases in electricity
      prices.

      (b) A more pessimistic view of the fuel savings could be                                 1982         1983       1984    1985        1986
      taken. This would involve:
                                                                                  Capital    -270000

                                                                                  Costs
      (i) Heat pumps cost (500KW x 10 hours x 125 days @ .03)                  Savings        37010         37010    37010     37010      37010
                     = £18.70
      (ii) Hot water heaters cost (1000KW x 8 hours x 155 days
                   @ .08)       = £22.30                                      The DCF calculations are:
      (iii) Oil saving as per estimate = £78.08                                                               @ 15%              @ 20%

5.2   Capital expenditure                                                     Net present value in £          -127,327           -137,181

      Many firms currently installing energy - related costs have             Yield/IRR                                       -15.97%
      found a substantial over-run on capital expenditure. There is
      also some question concerning £10,000 expenditure on the                The project is clearly not worthwhile.
      CPC2 building for necessary modifications to the air
      conditioning system (required by the installation of heat               7       Optimistic scenario
      pumps).
                                                                                      The capital expenditure and fuel savings are taken as per
5.3   Maintenance costs on heat pumps and hot water.                                  original estimate (i.e. as in section 4). No maintenance is
                                                                                      assumed.
      No allowance has been made for maintenance costs and it is
      highly likely that over a five year period some maintenance                     (a) Assuming labour savings of £7,500 (1/3 of £22,500) then
      will be involved.                                                               the DCF calculations show a yield/IRR of 19.5%.

      See below.                                                                      (b) Assuming no labour savings but a 25% Energy
                                                                                      Technology grant, then the DCF calculations show a yield/IRR
5.4   Labour savings                                                                  of 34.4%.

      The heat pumps and hot water heaters will require some labour                   (c) Assuming both a 25% Energy Technology grand and
      to maintain the equipment and buildings. It is likely that any                  labour savings of £7,500, then the DCF calculations show a
      labour savings will be more than compensated by additional                      yield/IRR of 34.4%.
      maintenance labour and/or parts.
                                                                              (b) and (c) are clearly worthwhile whilst (a) may be viewed as more
                                                                              marginal. Since labour savings are unlikely to be achieved (or
                                                                              compensated by maintenance costs) (b) is probably the most
                                                                              feasible. Hence (b) was used in 2.5.




                                                                         58
N.K. Tovey         ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                     Appendix 2



                                          C. SUMMERTIME HEATING: HEAT PUMPS

                                 Summary of Conclusions of Paper by Dr. N.K. Tovey

                                                                                  Minimum savings £49750
After a detailed analysis of relevant climatic data, and several
technical matters relating to the Heat Pump Project, the following                For the maximum savings the assumptions are:
conclusions are drawn:
                                                                                  Extended heat pump use starting late March finishing early
1.       The heat pump running costs given in B. Mitchell's                       November. Primary main isolated at 2 points indicated
         document are substantially overestimated. This arises                    above. Boiler shutdown 2 days after improvement in
         from a 25% overestimated in the number of days the heat                  weather in early May and restarted about 1 - 7th October.
         pumps will be required, and a significant overestimate on                Careful control of heat pump use. A diversity factor
         the average daily use. Even a most pessimistic approach                  included in EHWS calculations.
         gives only 60% of the quoted figure.
                                                                                  For minimum saving the assumptions are:
2.       Likewise, the costs of running the EHWS are
         overestimates - the maximum likely being about £2000                     no extended heat pump use or primary main isolation.
         below that quoted.                                                       Boiler shutdown 21/2         + weeks after weather
                                                                                  improvement. Almost no control of heat pump operation.
3.       The boiler house savings are overestimates. At present it                No diversity factor in EHWS calculations.
         is difficult to justify more than 75% of the quoted figure.
                                                                            7.    It is desirable that the heat pump be equipped with dual
4.       The project has not considered the marginal costs of                     thermostats; on for morning use, the other for evening use.
         heating via oil as opposed to heat pump. The latter are                  The morning thermostat should be set in the range 18.0 -
         only 50% of the former even more when the main boiler is
         on and we would be very foolish not to recognise this and                18.5oC (approx. 650).
         thus extend the period of operation of the heat pumps.
                                                                            8.    Before proceeding the University should explore the
5.       If we recognise that an extension of the operation of heat               possibility of installing longer heat pumps capable of
         pumps is desirable, then it will then become economic to                 whole year operation as these are cheaper to run even
         isolate 2 sections of the primary heating main i.e. at the               when the main boiler is on.
         Sports Centre, and at Suffolk Walk during the extended
         heat pump operation.                                               9.    Provision of HWS be other means should be investigated
                                                                                  before a decision on an electric system is made.
6.       Several different causes of action have been considered.
         With each of the costings, there being no fewer than 288           10.   If the University implement such a heat pump scheme it
         different possible estimates. However, the extreme range                 will obtain considerable publicity as a result of these
         is:                                                                      energy conservation strategies.

         Maximum savings £85520




                                                                       58
N.K. Tovey           ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                          Appendix 2

                                      Detailed Comments by Dr. N.K. Tovey
                                                         on
                              Document entitled University Plain : Summertime Heating
1.    Introduction
                                                                                    7) July, August and September 1977 differed from average
      Several technical matters arising from the document prepared                  months by no more than 3% in each case. The global 'degree-
      by B. Mitchell and dated 6th October 1981 are considered in                   days' for the three months was exactly the same as the
      this report. They are grouped under three headings:-                          corresponding aggregate in an average year.

      1. An evaluation of climatic data to enable realistic                   2.2   Analysis of Data
      assessments of the heat pump usage to be made.
                                                                                    The 12 temperature reading were average to produce a daily
      2. An assessment of the heat pumps to predict their                           mean. In addition the mean temperature in the period 0700-
      performance in meeting dynamic as opposed to steady state                     1700 on working days was evaluated when it was clear this fell
      situations.                                                                   below 58oF. The data is presented in Tables 1-6 in the
                                                                                    Appendix and each table covers one of the following periods:-
      3. An appraisal of the costs and savings based on data
      obtained in 1 and 2 above.                                                       (i)        1st - 15th May
                                                                                       (ii)       16th - 31st May
The main conclusions for each section are summarized in the general                    (iii)      1st June - shutdown
     conclusion at the end of this report.                                             (iv)       1st July - 15th September
                                                                                        (v)       15th - 30th September
2.    Climatic data                                                                    (vi)       1st - 15th October
2.1   Introduction
                                                                                    These tables show the Temperature distribution in 2oF classes.
      The heat requirement of a building is directly proportional to                All classes above 60oF (15.6oC) are lumped together as at this
      the temperature difference between the inside and outside. To                 temperature, incidental gains from body heat, appliances,
      assess the likely demand for heating the daily ambient                        lighting etc. are sufficient to produce an acceptable internal
      temperature records kept at the UEA boilerhouse were                          temperature.
      analysed. Attention centred on the periods May - June for the
      years 1977 - 81 and September 15-October 15 for the years
                                                                                    Between 58o and 60o, incidental gains will frequently be
      1977 - 80. In addition data for the whole of July, August and
                                                                                    sufficient to avoid the use of direct heating in residences.
      the early part of September 1977 were obtained.

      The raw data is in the form of regular 2 hourly measurements                  In working buildings, an external temperature of 58oF will
      of the external temperature and some 6000 such measurements                   give rise to at least 63oF will give rise to at least 63oF
      were scanned in this analysis. As a check on the validity of
      the periods chosen the 'degree-days' for each month were                      (external temperature of 60oF will give approximately the
      compared with the averages over the period 1957 76.                           maximum legal permitted temperature in most of our
                                                                                    buildings).
      The following conclusions were draw:-
                                                                                    To cover the possibility of heating requirements to the
      1) The average May for the selected period (i.e. 1977 - 81)                   teaching wall and other administrative areas during the
      was 6% colder than average.                                                   shutdown, Tables 7 - 11 relating only to working days were
                                                                                    complied. To allow for cold mornings and capacitance effects,
      2) The average June for the same period was 10% colder than                   the averaging period was extended to include 07.00-09.00 in
      average.                                                                      addition to the working day.

      3) The average September was 3% warmer than average                     2.3   Conclusions from the temperature data
      (although it should be noted here that the degree days relate to
      the whole month and not the last 15 days used here).                          (i) No heating is necessary July 1st - 15th September in
                                                                                    working areas, the one slightly cool easily be accounted for by
      4) For the month of May the years 1977, 1978 and 1979 were                    the substantial thermal capacity of the buildings.
      all much colder than average (15% for 1977).
                                                                                    (ii) Heating may be required occasionally in residences in the
      5) For the month of June, 1977 was over 50% colder than                       late evening during the period July 1st - 15th September.
      average, and was the coldest June since 1957.
                                                                                    (iii) In June there is no definite heating requirement in working
      6) October 1977 was significantly warmer than average                         areas although possible/probable on one day in June.
      (20%) while October 1980 was significantly colder (once                       However, most of these days occurred in 1977 which was 50%
      again 20%).
                                                                         58
N.K. Tovey        ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                           Appendix 2

    colder than normal and the main boiler would have been on
    anyway.                                                                2.4    Operating Strategies for the Boiler and Heat Pump

    (iv) Similarly in late September, 80% of days do not require                  The temperature normally shows a marked improvement in
    heating with no definite requirements.                                        early/mid May, and thereafter considerations for shutting the
                                                                                  boiler down can be made. The charts in Fig. 1 and 2 show the
    (v) The average May day in the period analysed was 9%                         boiler in operation about 2 days after the improvement and
    colder than average but it is clear that there is no scope for                thus represent optimistic shut down dates.
    shutting down the boiler much before 15th May. In 1981 it
    could have been shut down about 7/8th May.                                    It is suggested that in a more realistic schedule, the boiler
                                                                                  should be kept on for seven days after the improvement in the
    (vi) In 1979 it was certainly possible to have had no boiler                  weather supplying heat as required. Thereafter the residences
    operational until 15th October but in other years, a start up                 should be switched over to the heat pumps, for providing heat
    close to 1st October would have been necessary. In 1978,                      in the evenings. The teaching buildings should remain 'on' and
    there was a two week mild spell during which the boiler could                 in one year in five it is possible that short term boiler
    have been turned off again.                                                   operations (~ a few days) may be necessary up to June 10th
                                                                                  but during this time heat pumps can supply the needs in
    (vii)         During the period 15th May - 1st October the                    residences.
    total number of days with possible heating requirements in
    teaching areas were as follows:-                                              At the end of September, the boiler should be ready for start up
                                                                                  by October 1st, although this may be delayed up to two weeks.
        1977     1978      1979      1980      1981                               No substantial maintenance should thus be done on the boilers
                                          (to Sept 15th)                          before about 15th June or after 15th September.
        22       19        10        8          1
                                       (no data available                  2.5    Boiler and Heat Pump Use
                                        yet for last 15 days)
                                                                                  The distribution between boiler use and heat pump use in the
    (viii)       An operating schedule has been produced for the                  periods 1st May - 24th June and 15th September - 15th
    above period during the relevant years assuming that the heat                 October are shown in Figs. 1 and 2. The hatched areas
    pump had already been installed (See Figs. 1 and 2).                          represent possible heat pump use during the period.

        1977      Boiler off on June 9th with a possible short term               (i) The average number of 'boilerless' days is 140 but the
    shut down in late May                                                         optimum.
        1978      Boiler shut down 25th May
        1979      Boiler shut down 13th May                                       (ii) A realistic schedule suggested in 2.4 above would reduce
        1980      Boiler shut down 13th May                                       the average to 130 days.
        1981      Boiler shut down 7the May
                                                                                  (iii) A pessimistic schedule would reduce the number further to
    (ix) If this strategy had been adopted, then the number of                    120 days.
    possible heating requirements in teaching/administrative areas
    are as follows:-                                                                   20 days use up to the end of June
                                                                                       26 days use up to 15th September and
        1977     1978      1979      1980      1981                                    12 days after 15th September
         8        8         4         8         1                                      i.e. a total of 58 days.

    (x) Capacitance effects are sufficient to permit no heating on               (iv) However, these figures relate to the optimum 'boilerless'
    slightly cool days provided they are not grouped continuously.               strategy in 2.5 (i).
    Capacitance effects are certainly sufficient to cope with a
    single day, and are probably sufficient for two days.                             For the realistic schedule in 2.4, the corresponding figures
    Removing such days from the analysis leaves:-                                would be:-

        1977     1978      1979      1980      1981                                    16 days to end of June
         0        0         0         5         0
                                                                                       26 days in July, August and early September
        Where there are two consecutive cooler days the second of                      10 days after 15th September
    these has been indicated by + on the chart. There is, on
    average, 1 such period a year.                                                     giving a total of 52 days.

    (xi) The 5 days in 1980 formed a continuous group in May                     (v) Using the pessimistic scenario and assuming extra boiler
    (20-25). The temperature was sufficient to provide heating to                use is at both ends of period gives for the same figures:-
    the standard required by the Office, Shops and Railway
    Premises Act 1963, but it must be assumed that had no general                      14 days to end of June
    heating been provided during this period some supplementary
    heating would probably have been in use by secretaries.                            26 days in July, August and early September
                                                                      58
N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                        Appendix 2


          8 days after 15th September                                       3.2 Sizing of Radiators

          giving a total of 48 days use.                                       The heat pump delivers water at 45oC which is 20oC colder than
                                                                               the normal operating temperature of the radiators. Consequently
2.6 Implications for costs and savings                                         less heat will be radiated from them.
   1.    A period of 150 days is too long for a realistic shut down
   in an average year.                                                         For radiative heat transfer the heat flow is proportional to T4rad
                                                                               - T4air.
   2.     This figure should be reduced to about 130.
                                                                               Substituting the relevant values gives a heat transfer rate which
   3.    Under all these scenarios, the heat pump usage for
                                                                               is about 51% of normal.
   auxiliary heating is significantly less than assumed in the
   document on summer time heating.
                                                                               Heat transfer from radiators in only partly via radiative means
                                                                               and using an alternative approach assuming equivalent
   4.     A summary of the three scenarios is given in the following
                                                                               conductive values give a figure of 57%.
   table.
                                                                               For convenience the mean value of about 54% is assumed.
                    Optimum Realistic Pessimistic
                    Scenario Scenario Scenario
boilerless days               138                 130                          The heating will have been designed for -1oC external
             120                                                               conditions (i.e. 16.5oC temperature difference from the balance
heat pump use                   58                 52                          temperature). This gives a maximum heat load of 924KW.
             48                                                                Normally radiators are over-sized by up 20% to allow for
                                                                               dynamic effects, i.e. the maximum heat output under normal
         The optimum scenario requires short term operation of the             conditions would be approx. 1M.
   boiler on one or two years in five. The other two scenarios do
   not make this assumption and assume continuous boiler use until             Thus we can expect the radiators to handle up to 540KW when
   shut down.                                                                  connected to the heat pump. This figure is precisely that of the
                                                                               output of the heat pump at 10oC and thus provides a satisfactory
3. Assessment of Technical Aspect of Heat Pumps                                match to our existing system.

3.1 Introduction                                                               If the heat pump were operating at say 13oC when the combined
                                                                               output of the two Waveney Heat pumps is 600KW, the
                                                                               temperature of the circulating water would probably rise thereby
   To assess the likely performance of the heat pumps, one of the              reducing the COP slightly. Conversely for temperatures less
   residences has been selected for a detailed study namely                    than 10oC, the radiator temperature is likely to be a little lower
   Waveney Terrace.                                                            creating an increase in the COP.

   A heat loss rate of 56KWoC-1 has been assumed being the mean                For subsequent design purposes it would seem sufficient to use
   value I believe agrees closely with that used by B. Mitchell.               the quoted figures.

   A thermal capacity of 6GJoC-1 has been assumed - this being
   the mean of two separate assessments. It is possible that this           3.3 Assessment of likely use of Heat Pumps
   figure may be in error and an assessment of the effects of
                                                                               The days on which heat pumps are likely to be required are
   changing the value from 3GJoC-1 to 9GJoC-1 was done.                        shown in Figs. 1 and ??. This must be regarded as somewhat
   Though the actual temperatures varied in response, the overall              pessimistic as almost certainly no heating will be required for
   energy consumption was no more than 10% different and thus                  isolated days and probably not for two consecutive days either.
   the calculations are fairly insensitive to substantial changes in           However, in this analysis it is assumed that these are 'heating
   thermal capacity.                                                           days.

   An occupancy of 500 persons (c.f. 750 rooms) for the hours                  Five days were selected within the periods studied.
   20.00 - 08.00 is assumed and 200 at other times.

   An average of 80W person consumption in appliance is assumed                These were 17th June 1981 when the mean temperature was 57 o,
   and allowances are made for incidental gains from hot water and             25th June 1981 (54.6o), and a series of three consecutive days
   cooking.                                                                    29th September - 1st October 198?, which was the coldest spell
                                                                               in all five years studied. In fact even the optimum strategy
   Solar gain data for a cloudy day in June has been assumed - i.e.            suggests that the baler would have been on to cover this period.
   diffuse gain which should be the same for both sides of building.

                                                                       58
N.K. Tovey            ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                                  Appendix 2

     A thermostat setting of 19.5oC was initially assumed with                         thermostat was set at 18.5oC for the morning period. The
     heating possible between 17.00 and 23.00, and a single 1 hour in                  minimum and maximum likely daily costs for heating Waveney
     the morning. For the 'cooler' days the 1 hour is probably                         for the three day period are £90 and £96 respectively.
     inadequate, and a possible 2 hour heating period 07.00 - 09.00
     was assumed. Realistic incidental gains were assumed as was                       The calculations used in the above assumed dull solar gain
     the diffuse solar gain obtained on a dull day even through it is                  conditions and a thermal capacity of 6 GJ. It is this last factor
     clear some of the days had direct solar gain.                                     which reduces the demand in cases tested below, from that
                                                                                       predicted from simple mean temperature conditions, we were
     Note: The current maximum legal setting of thermostats is                         careful in the use of the heat pumps the actual demand would be
     19.0oC although residences as excluded from this regulation, the                  about 50% of that predicted from simple mean temperature
     intention has been that this should be universally applied                        conditions. Even the most pessimistic value is only 70%. Thus
     throughout the University. In the subsequent analysis a figure of                 the values obtained from mean temperature data must be
                                                                                       regarded as being the maximum possible demand.
     19.5oC (upper limit - 19.0 lower limit) has been assumed. This
     will tend to overestimate consumption over that which would                       Costs for running the heat pump range from £2770 for the
     have occurred had 19.0oC been used.                                               maximum possible cost with the optimum distribution between
                                                                                       boiler and heat pump use and £1045 for careful management of
                                                                                       heat pump use with the pessimistic distribution. The full details
     In some of the analyses a morning thermostat at 18.5 oC is
                                                                                       are given in Appendix 1.
     assumed. This undoubtedly would permit better control and the
     lower setting can be justified as people's activity level is usually
                                                                                 3.4 The COP's of the heat pumps
     significantly higher at that time, and also the incidental
     (particularly diffuse solar) gains will normally cause the
                                                                                       From the data quoted, the isentropic efficiency is 41% - 43% for
     temperature to continue to rise about this temperature.
                                                                                       all external conditions. We can assess the likely values of COP
                                                                                       with different high temperature conditions. For instance if we
     (i)    June 17th 1981
                                                                                       were aiming to provide water at 65oC and not 45oC we should
                                                                                       expect lower COPs.
a)    The temperature fell to a minimum of 18.3oC (65oF) overnight,
      the two hour heating brought the temperature up to 19.0oC by
                                                                                                             OoC      5o     10oC       13oC
      mid afternoon and no heating was necessary in the evening, see
                                                                                 isentropic efficiency       42.6    43.8    42.9       41.1
      Fig. 3(a).

b)    Had only one hour heating been provided, the temperature                         45o                   3.01    3.48     3.90       4.08
      would have risen to 18.6oC by 08.00, but incidental gains                        47.5o                2.70     3.02     3.42       3.72
      would have kept the internal temperature in the evening about                    65o                  2.08     2.25     2.46       2.60
      the thermostat setting.

c)    If no heating had been provided in the morning, the temperature                          (The figures for 47.5o and 65oC assume an isentropic
                                                                                               efficiency of 40%)
      would have fallen to 18.2oC thereafter incidental gains would
      have increased the temperature, and only in the late evening
      would heating have been required.                                                        Normal heating systems operate with about 10oC between
                                                                                               flow and return temperatures. As we are expecting only
d)    The costs for heating Waveney for that day would have been                               50% heat output during the period of operation a 5 oC
      £8.50, £4.30 and £1.00 respectively.                                                     temperature difference is likely. Thus we may have to
                                                                                               expect a top temperature of 47.5oC with a consequent
     (ii)   June 25th 1981                                                                     increase of about 10% in the electricity consumed.
     The analysis is summarised in Appendix 1, 2 hours morning                   3.5           Auxiliary Electric Hot Water Services
     heating necessary, cost £15.30, (with morning thermostat at
     18.5oC £14).                                                                              It is proposed to instal an extra 192KW of electric hot
                                                                                               water heating in addition to the 508KW? (700 -192KW) at
     (iii) 29th September - 1st October                                                        present in residences etc. I understand that the five hour
                                                                                               suggested period is based on actual existing information
     Two hour heating in the morning is definitely required during                             relating to Waveney Terrace (verbal communication from
     this period. the mean temperatures on the three days were                                 B. Mitchell).
     53.0oF, 48.8oF. if only 2 hours morning and 6 hours evening
     heating were available, it would not be possible to raise the                             Of the total installed capacity of 700KW, 496KW would
                                                                                               be in areas needing it 7 days a week in summer. This
     temperature in the evening above 19.2oC. Alternative strategies                           figure is derived as follows:- 508 existing less Arts I less
     might include the manual over-ride of time switch to give the                             Arts II + Laundrette.
     possibility of continuous heating on these days controlled by
     thermostat only. Some economy could be achieved if the
                                                                            58
N.K. Tovey        ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                  Appendix 2

       In assessing the use of heaters for hot water we should               costs of heating directly and by heat pump will be less but
       allow for only 5 days use in teaching/administration areas.           in the same proportion.
       Further the resulting figures will provide more than
       adequate water (e.g. over 500 galls in ENV/MAP).                      The figures for oil assume efficiencies of about 85% below
                                                                             5oC falling to 75% above 13oC. A calorific value in the
       Further we should allow for the fact that at present we use           range 38 - 43 MJ/litre is used.
       the existing heaters for two weeks a year.
                                                                             The data is plotted in Fig. 5 and clearly shows that at all
       Finally we may wish to consider a more realistic strategy             temperatures down to that for which the proposed heat
       for the residences in the vacation - i.e. a 60% load factor at
       this time, 100% during the rest of the time.                          pumps can supply all the heating (i.e. 7oC) oil is twice as
                                                                             expensive as using the heat pump.
       The calculations are as follows:
                                                                             We would be foolish not to recognise this fact since from
       (i) existing use 508 x 14 days x 5 hours = 35560 kWh                  April 1st we could switch over to heat pumps in the
                                                                             residences but retain boiler heating in the rest of the
       (ii) teaching/admin. use at 5 days a week                             University.

       strategy     optimum      realistic pessimistic                       Indeed we should actively consider switching over to heat
       days use        100         93         86                             pump use in residences from the start of the Easter
                  102000 kWh 94860 kWh 87720 kWh                             Vacation but continue running the boiler until May defined
                                                                             in the three strategies. The boiler would be brought on
       (iii)      other buildings                                            again at about October 31st and possibly November
                                                                             10th/15th.
       strategy      optimum           realistic pessimistic
       days use        140               130          120                    The direct savings here are estimated at £14000 or a
  a)   no diversity 347200 kWh         322400 kWh 297600                     minimum £6300.
  b)   with diversity 267840 kWh       252960 kWh 238080
                                                                             In addition to the direct savings, there would be no need
       The total extra use in electricity is thus assessed as                for the boiler to operate after about 10.00 and it could be
                                                                             placed on stand-by until about 06.00 the next morning.
       strategy             optimum       realistic   pessimistic            Whilst it is true that a somewhat similar strategy could be
       no diversity         413640        381700       349760                adopted at present, the period could be extended firstly
       with diversity       334280        312260       290240                because the residences will be self-sufficient in late
                                                                             evening, and secondly the peak demand the next morning
3.6    Savings in Boiler house Electricity                                   will be much lower. We could expect £2500 saving by
                                                                             this means. If the Library and University House had
       The document 'SUMERTIME HEATING' is approximate                       auxiliary heating then the shut-down to stand-by could be
       in its assessment of boilerhouse use of electricity. It               much earlier each evening.
       mentions 15 hp fans but it is not clear how many there are
       for each boiler since we can only consider that one boiler            A similar analysis was done to examine the situation for
       is in operation during the relevant period. However,                  continuation of the hot water supply by auxiliary means.
       assuming that 40kW is reliable, the savings estimated in              Here the marginal costs are such that only if all the water
       that document must be over estimated as they do not                   was heating at off-peak rates with no afternoon boost
       account for the fact the for 7 hours, the cost would be at            would it be advantageous to extend the auxiliary heating
       the night time rate. Redoing the calculations using 40 kW             season.
       for the relevant periods gives
                                                                             Under the proposal, the cost for supplying hot water to
       strategy             optimum realistic           pessimistic          Waveney would be
       days                  140     130                     120
       energy use           134400 124800                 115200             Electricity £9 per day (4 hours off-peak 1 hour peak)
       savings              £3445 £3200                    £2955             Oil       £8.40 per day

3.7    Marginal Costs of Heating Residences                                  However, the heat loss from the main flow and return lines
                                                                             alone from the Sports Centre to Orwell Close would
       Although consideration has been given to use of heat                  amount to £15 - £20 day, and taking these into account it
       pumps during the 'boiler-less' period a check must also be            clearly becomes attractive to isolate that section of the pipe
       made whether or not the marginal costs for heating the                line. Similarly, the Suffolk Walk/Suffolk Terrace sections
       residences when the boiler is on one greater or less than             could be isolated.
       using a heat pump.
                                                                             The overall savings as a result of this alternative strategy
       For ease of comparison the figures are calculated with                amount to about £20,000.
       respect to the mean temperatures and these represent the
       maximum possible in both cases. In actual practice the
                                                                        58
N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                              Appendix 2

          It must be pointed out that even at temperatures colder
          than 7oC the heat pump operation would represent                    Note
          savings, and except on the very coldest days of winter the           (i)     These savings do not include any obtained by extended use
          most cost effective strategy would be to run the heat                        of the heat pumps.
          pumps for most of the year. However the sizing of the                 (ii)   Although these figures are to some extent based on the
          pumps in the proposal are less than half that which would                    mean for 5 years, and that it can be argued that existing
          be required for all the year heating. Before committing                      conservation measures in operations may have reduced
          ourselves to a particular size of pump it might be prudent                   these figures slightly, the figure used by B. Mitchell refers
          to examine installation of larger pumps -for instance if                     only to 1981, which was warmer than average and
          capacity were sufficient we could expect an extra saving of                  underestimates the saving over the period. In any case, the
          £6,200 per annum for Waveney Terrace or £17,670                              central scenario projects a slightly lower value than his
          overall.                                                                     projection.

3.8       The Teaching/Administration Areas                                   4.3       Savings in boiler house electricity

          It is clear from the above that if we installed heat pumps                    The savings quoted by B. Mitchell are optimistic - see 3.6
          for each building we would save significant quantities of                     and the following are more realistic unless further
          money. However, this is not considered here as it raises                      information is forthcoming:
          several other fundamental questions. However, alternative
          strategies to electric heating might be considered:-                          strategy   optimum     realistic          pessimistic
                                                                                        saving      £3445       £3200              £2955
  (i)     the use of small gas boilers in all teaching area to provide
          hot water. The capital cost of this is likely to be greater         4.4       Auxiliary EHWS costs
          than electric heaters but the running costs would be less.
          Further at least one firm to my knowledge has negotiated a                    The extra electricity consumed in these heaters is
          favourable rate for gas because they take a higher quantity                   estimated in 3.5. The savings calculated from these
          of gas in summer. We may be able to obtain similar                            figures are:
          concessions e.g. it helps the Gas Board to balance their
          supplies between summer and winter.                                           strategy   optimum            realistic         pessimistic

 (ii)     In some Science buildings considerable quantities of waste                    no diversity
          heat are ejected to the atmosphere. For instance, the ENV                     factor:      £7446            £6871                 £6296
          cold rooms have refrigerators (heat pumps) and the exhaust
          from these could be used as the cold source for a small                       with diversity
          water to water heat pump for providing hot water instead                      factor:      £6017            £5621                 £5224
          of immersion heaters. The same is true for the other
          science buildings (see document written by myself dated             4.5      Costs of running heat pumps
          2.12.75).
                                                                              The costs for running the heat pumps are as follows:
          These two comments do not affect the implementation of
          the general scheme but must be considered when                      Strategy          optimum           realistic             pessimistic
          examining the additional auxiliary HWS.                             maximum possible £2770                 £2500                 £2130
                                                                              poor control    )    £1884             £1700                 £1448
                                                                              reasonable control ) £1607             £1450                 £1235
4. Assessment of the Economic Aspect
                                                                              careful control ) £1357                £1225                 £1044
4.1       Introduction
                                                                              The control regimes relate to how carefully the use of the heat
                                                                              pumps is controlled. To allow for possible mismatch between heat
          Some of the economic aspects of particular strategies have
                                                                              pump and heating system, these costs should be inflated by 11%.
          been discussed already. in this section the global effect on
          costs is studied. In addition, several comments on the              This represents a flow temperature of 47.5oC and a return of 42.5oC.
          paper by Professor Bhaskar are made.
                                                                              i.e.:
4.2       Oil savings                                                         strategy               optimum       realistic          pessimistic
                                                                              maximum possible         £3075        £2775                £2364
          The document of B. Mitchell suggests a saving of £63,200            (poor control
          per annum. Using statistics for the past 5 years predictions        ((69% of max. possible) £2091           £1887                 £1607
          of soil savings for the three strategies are:                              | (reasonable control
                                                                              likely | ((58% of max. possible)
                    optimum              realistic        pessimistic         costs |                  £1784          £1610                 £1371
                    strategy            strategy            strategy                  | (careful control
                                                                                      | ((49% of max. possible)
litres              575595              511940              455340                                    £1506           £1360                 £1159
savings             £70,100             £62,350             £55,460
                                                                         58
N.K. Tovey            ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                                 Appendix 2

                                                                                                  3.         With continued increases in the size of power
4.6         Overall savings without extended heat pump use                                          stations the labour costs per unit have decreased.

            The overall savings are as follows:                                                   4.        The historic trend clearly demonstrates the fact
                                                                                                    as indicated below:
strategy:          optimum               realistic          pessimistic                                                (Indices 1976 = 100)
                                                                                                                Retail      Cost of       Cost of     Cost
savings             £73545                £65550              £58415                                             price    Heavy Oil     Electricity    of
 costs: max.        £10521                 £9646               £8660                                            index      to Power      to Large    Heavy
     min.            £7523                  £6981              £6383                                                        Stations    Consumers      Oil

SAVINGS :                                                                                       1971             50         27             44          32
     MIN          £63020                  £55900               £49750
     MAX          £66020                  £58570               £52030                           1976            100        100            100         100

                                                                                        1980                    174        207            161         209
4.7         Overall savings with extended heat pump use
                                                                                  Compound Increase             3%         23%            14%         21%
                                                                                     1971 - 1980
            The savings from extending use of heat pumps to cover
            period 20th March - 7th November would increase savings               Compound Increase             12%        16%            10%         16%
            by about £6300 minimum to £14000 maximum possible                        1976 - 1980
            depending on the exact length of the period chosen.

            Increased savings from increased standby as opposed to                ----- whereas electricity increases have been comparable with
            operating for boiler with above strategy - £2,500.                    inflation, oil prices have gone up 4% - 9% in real terms. A realistic
                                                                                  scenario could thus incorporate a 2% real increase and an optimistic
            Increased savings id main pipes are isolated beyond Sport             one a 4% increase.
            Centre and Suffolk Walk - £3,000.
                                                                                  4.10            Comments on document by Professor Bhaskar
            Overall additional saving ranges from £6,300 to £19,500.
                                                                                         (i)      It is assumed that the project life is 5 years and this is
                                                                                                    based on industrial experience. This is an unrealistic
4.8         Other savings                                                                           comparison. I myself have had contact with energy
                                                                                                    managers at some major industrial firms. Two reasons
            As a result of the increased shutdown period maintenance                                emerge for the maximum of five years. Firstly, many
            will be improved, and we might expect an overall ½%                                     schemes are related to processes etc. which have limited
            improvement and optimistically a 1%. In a pessimistic                                   life spans - say, 10 years maximum and secondly, there
            scenario we should assume no change. At a cost of about                                 are usually energy conservation schemes which can be
            £500,000 for fuel oil, deduct the savings outlined above                                implemented which have much shorter pay back times.
            and figures of £2000 (for ½%) or £4000 (for 1%) are                                     A life time longer than five years would not be
            obtained. These could be included in the respective                                     unrealistic in our case.
            scenarios but I have chosen not to do so at this stage
            merely to point out a qualitative 'plus' for the scheme. In a                (ii)     Comment relating to assumptions over oil prices has
            similar way, we can expect a significant improvement in                                already been made in Section 4.9.
            the life of the boilers not only from the decreased use, but
            also by removing the extended periods of low use                     (iii)          The figures used in the pessimistic scenario are totally
            operation. A 50% increased life expectancy of our boilers                           unreasonable:
            might not be unreasonable.
                                                                                         (a)    Heat pump running costs:
4.9         Future oil costs                                                                    - these assume 10 hours a day running for 5 days in 6 - such
                                                                                                an extended run will only occur on days as cold as 50 oF of
            All the calculations have been done using present day                        which on average there is only one per season - secondly, it
            prices. It is generally accepted that oil prices will rise in                assumes a COP of only 2.28. Even the most pessimistic
            real terms and this will increase the value of the savings.                  approach would give a COP of 3 for the temperature range
            Professor Bhaskar argues that it is prudent to neglect this                  considered -as shown above, even B. Mitchell's estimate is
            advantage. While this might be so in a pessimistic                           very much on the pessimistic side and his figure of £5000
            scenario, it ought not to be for the realistic or optimistic                 should thus be regarded as the most extreme figure.
            scenarios. The reasons for this are fourfold:                         (b)    The EHWS costs reflect 300 KW over the maximum
                                                                                         installed capacity. Even if the other figures are accepted,
            1.        Only 12% of electricity is generated from oil.                     which is questionable, the estimated figure is 42% too high.
            2.        Continued improvements in the thermal        (i)            Professor Bhaskar raises the possibility of cost over-run. This is
              efficiency of the power stations mean that less fuel is                    certainly a possibility and it would be desirable to have more
              used. This trend will continue at least for the next 5                     detailed costings particularly of the acoustic covers.
              years.

                                                                            58
 N.K. Tovey          ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                         Appendix 2

                                                                               Evaluation of Probable Heat Pump Costs

5. Conclusions                                                                 Mean Temp 57oC, see Fig. 3
   The following conclusions about the project can be drawn:                            1st scenario, 2 hours heating in morning thermostat (19.5)
                                                                                                            £8.40
   1.    The assumption of a 5-month (150 day boiler shutdown) is
         over-optimistic.                                                               2nd scenario, 1 hour "      " "       "
   2.    An optimum shutdown period would last, on average, 140                                              £4.20
         days, but this would require shutting the boiler down within                   (also equivalent to 2 hours with thermostat at 18.5)
         2-3 days of the improvement in weather in May. Further, it
         may be necessary to use the boiler for a further short period         No morning heating (minimum temperature 18.2)
         in late May or June on one year in three.                                                       £1.00
   3.    A more realistic strategy would allow 7 days of good
         weather before shutdown. This would, in general, eliminate
         bringing the boiler back on again. The shutdown period                Mean Temp 54.6oC
         would be reduced to 130 days.
   4.    A pessimistic strategy would allow a further 10 days of                      2 hours morning heating + thermostat at 19.5
         boiler operation before shutdown reducing the 'boilerless'                              £15.30
         period to 120 days.                                                            if morning thermostat were set at 18.5
   5.    Even in the optimistic shutdown period, the use of heat                                 £14.50
         pumps is over-estimated in the report by B. Mitchell.                          (minimum temperature for both scenarios 18.0)
         Figures for the three strategies based on average climatic
         data for the past 5 years are 57, 51 and 45 days respectively.        Mean Temp 53oC day 1 of Fig. 4
   6.    Detailed analysis of selected days shows that the figure of
         £5000 for heat pump operation grossly overestimates the
                                                                                        2 hours morning heating needed, with or without 18.5oC
         likely cost.
                                                                                        setting (minimum overnight temp 18.0)
   7.    Re-computation of EHWS costs shows a saving of about
                                                                                                          £22.00
         £2000 when allowance for only 5 day use in
                                                                                        Heating during most hours in evening, but not full amount.
         administrative/teaching areas is made. Further savings are
         apparent if a diversity factor is included.
   8.    The savings in boilerhouse electricity overestimates the              Mean Temp 48.8oC day 2 of Fig. 4
         potential savings by up to 50%.
   9.    The report makes no mention of the extended use of heat                        i) 2 hours morning heating + full on in evening
         pumps i.e. use in April and early November even when main                                          £34.00
         boiler is on. The marginal costs for heating the residences                    ii) continuously on but controlled by 19.5o
         are very much in favour of the heat pumps.                                                                  £44.00
   10.   Alternative means of providing HWS in the                                                                   oC thermostat until mid-day
         teaching/administrative buildings should be carefully                          iii)continuously on but 18.5
         examined before adopting an electrical method.                                                    £42.20
   11.   The possibility of installing larger heat pumps which could
         be capable of use in the winter should be explored. The               Note: scenario (i) does not permit 19.5oC to be reached in evening
         marginal costs favour heat pumps over the present scheme              thereby affecting next day.
         except on the most extreme cold days.
                                                                               Mean temp 50.5oC day 3 of Fig. 4
                                                        N.K. TOVEY
                                                                                        i) previous day as scenario (i) above then similar
                                                   19th October 1981.
                                                                                        operation                       £34.00
                                                                                        ii) following scenario (ii) above
                                                                                                                        £30.00
                                                                                        iii)following scenario (iii) above with continuous
                                                                                            heating controlled by 18.5oC thermostat in morning
                                                                                                            £32.00

                                                                               Note: if scenario (i) on day 2 is adopted, the minimum temperature
                                                                               overnight is

                                                                                                  16.62oC = 62oF.


                                                                                      Tables associated with paper appear on next page.


                                                                          58
N.K. Tovey     ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                         Appendix 2

                                                                                                          Mean Temperatures for Period 27th June - 14th September 1977
                                                                                                                 oF                           Number of Days
                                          Table 1
                                                                                                                   56 - 58                            11
                                                                                                                   58 - 60                            11
                    Daily Mean Temperatures for the Period 1st - 15th May
                                  at UEA Boiler House                                                               > 60                              55
                                                                                                                    Total                             77

                                                                                                                                      Table 5
        oF         1977           1978         1979          1980      1981       Total
     >44            1              -                          -             -      6                                Mean Temperatures for 15th - 30th September
    44-46           3              -            5             -             1      4
    46-48           2              -            0             4             1      9            oF           1977            1978          1979            1980          Total
    48-50           4              3            2             3             0      12
    50-52           2              6            2             1             0      9           50-52           -               -            2                -            2
    52-54           1              4            0             2             0      8           52-54          2                2            1                -            5
    54-56           1              0            1             0             0      2           54-56          4                2            2                -            8
    56-58           -              1            1             1             1      3           56-58          3                4            5                3            15
    58-60           -              1            0             1             2      4           58-60          2                0            1                4            7
     >60            -              -            0             3             7      14           >60           5                8            5                9            27
                                                4                                                             16              16            16              16            64
                    14             15           15            15          12       71
                                                                                                                                      Table 6
                                          Table 2
                                                                                                                      Mean Temperatures for 1st - 15th October
                            As Table 1 for period 16th - 31st May
                                                                                                oF           1977            1978          1979            1980          Total
   oF        1977           1978         1979         1980          1981        Total
                                                                                                >46            -               -             -              1             1
   <50        2               -            -             -            -           2            46-48          1                -             -              4             5
  50-52       1              2            2             1             -           6            48-50          0                -             -              2             2
  52-54       7              5            3             4            1           20            50-52          2               1              -              3             6
  54-56       2              2            3             1            1            9            52-54          4               2              -              2             8
  56-58       2              2            3             2            6           15            54-56          7               2             2               3             14
  58-60       1              1            1             6            2           11            56-58          0               2             1               -             3
   >60        1              4            4             2            6           17            58-60          1               4             3               -             8
              16             16           16            16           16          80             >60           0               4             9               -             13
                                                                                                              15              15            15             15             60




                                          Table 4

                                                                                          58
N.K. Tovey    ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                   Appendix 2

                                      Table 7
              Temperature Data for Working Periods Only 1st - 15th May                                      As Table 7 for Period 15th - 30th September
    oF       1977        1978         1979         1980         1981     Total
                                                                                       oF            1977         1978            1979             1980   Total
    <44        -            -          1              -           -       1
   44-46       -            -          3              -           -       3            <54             -             -               -               -      -
   46-48      1             -          1              -           -       2           54-56           1              2              1                -     4
   48-50      2             -          0             1           1        4           56-58           3              1              1                -     5
   52-54      4             -          1             4           1        10           >58            7              8              8               12     35
   54-56      0            2           2             1           0        5                           11            11              10              12     44
   56-58      2            3           0             1           0        6
    >58       0            2           1             0           0        3
              1            4           2             4           8        19                                                 Table 11
              10           11          11            11          10       53
                                                                                                              As Table 7 for Period 1st - 15th October
                                       Table 8
                        As Table 7 for Period 16th - 31st May                          oF            1977          1978           1979             1980   Total
    oF       1977       1978         1979          1980       1981       Total
                                                                                       <48             -             -               -               1      1
    <50        -           -           -            -            -         -          48-50            -             -               -               2      2
   50-52       -           -           -            -            -         -          50-52           1              -               -               2      3
   52-54      1           2           1             -            -        4           52-54           2              1               -               2      5
   54-56      2           3           5            4             -        14          54-56           1              1               -               2      4
   56-58      5           2           1            0             -        8           56-58           3              1              1                2      7
    >58       4           5           5            7            10        31           >58            3              7              10               0     20
              12          12          12           11           10        57                          10            10              11               11    42

                                       Table 9
                    As Table 8 for Period 1st - 26th June (approx)
    oF       1977       1978          1979          1980         1981    Total
    <50       1            -            -            -            -       1
   50-52       -           -            -            -            -       0
   52-54       -           -            1            -            -       1
   54-56      5           1             1            4            1       12
   56-58      4           1             0            0            0       5
    >58       8           15           19           16           19       77
              18          17           21           20           20       96




                                      Table 10

                                                                                 58
N.K. Tovey        ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                                       Appendix 2


                                                                          Table 12: Analysis of Temperature Data 15 May - 15 October


                                                                                      (i)      15/5 - end of June mean of years 1977-81
                                                                                     (ii)      July-15/9 year 1977 which is typical
                                                                                     (iii)     15/9-15/10 average of years 1977-80

                                                                           Number of Days in Each Class in 'boilerless' period
                    Temperature                            Total Period          Operating              Realistic              Pessimistic
                                                                                  Strategy              Strategy                Strategy
                                                                                (Figs 1&2)
                    <50oF Heating                               2.5                   0                     0                       0
                                                                3.3                  0.7                   0.7                     0.7
                    50-52oF "                                   9.8                  4.9                   4.5                     3.5
                    52-54oF "                                   9.5                  5.3                   4.9                     3.5
                                                               22.6                 22.6                  19.9                    18.0
                    54-56oF "
                                                               23.1                 23.3                  20.9                    19.3
                    56-58oF Probable Heating                   81.3                 82.9                  79.3                    75.5
                    58-60oF Possible Heating
                    >60oF No Heating
                    [incidental gains ~7-8oC]
                    Total Heating Days
                    (including possible and                    70.8                  56.8                   50.9                 45.00
                    probable)
                    Mean Temperature on Heating
                    Days only                                 56.27                  57.21                 57.19                 57.30
                    Approximate cost for
                    supplying heat to all
                    buildings equipped with                   £4610                 £2770*                 £2500*               £2130*
                    heating
                    Savings in Oil                                                 £70,100                £62,350              £55,460
                    Nett Saving                                                    £67,300*              £59,850*              £53,330*

  * Note: these figures assume maximum possible costs. Probable costs are likely to be significantly less, see Section 4.




                                                                                                      58
N.K. Tovey                ENV-2D02 Energy Conservation 2005 - 2006: Practical Handout 2                       Appendix 2

LATE APPENDIX TO COMMENTS BY DR N.K. TOVEY


ECONOMIC ASPECTS

The Net Present Values for the project using broadly the three scenarios given in the main paper are given below with the following
additional assumptions.

1. optimistic:           -       real increase in oil of 4%
                                 £40,000 ETS grant
                                 saving as per report £85,520

2. realistic:            -       no ET grant
                                 real increase in oil of 2%
                                 saving of £68,470

3. pessimistic:          -       no ET grant
                                 no real increase in oil
                                 cost overrun on acoustic covers and services by
                                 £20,000 to give total £270,000


The present day values are:


                               Life/Discount Rate                10%                  15%         20%
optimistic                               5yr                  +£171,856            +£140,841   +£112,255
                                        10yr                  +£457,201            +£349,048   +£266,906
realistic                                5yr                  +£45,251             +£22,132     +£2,659
                                        10yr                  +£246,194            +£169,834   +£113,098
pessimistic A                            5yr                   -£62,549             -£78,215    -£91,461
                                        10yr                  +£66,261             +£18,131     -£19,710
pessimistic B                            5yr                   -£36,279             -£53,928    -£68,852
                                        10yr                  +£108,843            +£53,494    +£11,985


Note: scenario Pessimistic B assumes some external heat pump operation which is probable.

Approximate values for the internal rate of return are:-

             optimistic          5yr       +60.6%
                                 10yr      +70.3%

             realistic           5yr       +20.7%
                                 10yr      +37.4%

             pessimistic A       5yr       -4.0%
                                 10yr      +17.4%

             pessimistic B       5yr       +2.0%
                                 10yr      +21.9%

Note: most works in public sector assume a 10% discount rate.




                                                                          58

								
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