Report for Solectair Pty Ltd by 8ae1Pwz

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									Solectair HTS Performance Estimations                    DRAFT DOCUMENT




    Estimation of the Performance of the
    Solectair Heat Transfer System under
        different climatic conditions




      A Report Prepared for Solectair Pty Ltd




                                        Phillip Calais

                                        November 2004



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Solectair HTS Performance Estimations                           DRAFT DOCUMENT

    1. Executive Summary

The Solectair Heat Transfer System (‘Solectair’) is a novel space heating system
designed for use in small to medium-sized buildings, such as houses, retirement
villages and medical centres. It utilizes the roof surface of a building as the solar
collector, the roof itself for short-term storage of heat and the roof-ceiling space as the
area from which the heat is collected and transferred to the indoor living areas. The
performance of the Solectair will be dependent, therefore on the building design and
construction, and the local climatic conditions, including solar insolation and the ambient
temperature.

This report uses data collected over a period of approximately two months in 2002 in a
Test House in Perth, Western Australia, to assess the effectiveness of the Solectair. It
also uses available meteorological data and other information to extrapolate the results
for a full year for Perth and to other locations around Australia.

The Test House in Perth was a double-brick/cavity wall and a tile roof house and with a
floor area of the living space of 140 m2.

The results of the analysis indicate that up to 70% of the annual heating requirements of
a house located in Perth similar in design and construction to that of the Perth Test
House could be provided by a Solectair. The estimate of the proportion of the space
heating requirements supplied from a Solectair to maintain a minimum indoor
temperature of 180C varied over the year from over 100% in the ‘shoulder’ heating
periods of autumn and spring to about 28% in mid-July. These results are consistent
with anecdotal reports.


 Graph 1: Proportion of Annual Space Heating Requirements provided by Solectair HTS for
 Perth Test House. Total heating requirements (red) and the heat provided by the Solectair
 HTS (orange area overlaid over red).




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Calculations of the cost savings of using a Solectair system with a gas or an electric
heating system to provide ‘boost’ heating indicated that the potential cost savings of
using a Solectair System are substantial. Compared to a ducted gas-only system, a
Solectair, in conjunction with a ducted gas system in a house located in Perth and
similar in design and construction to the Test House, could achieve reductions in annual
space heating running costs of approximately 56%. A Solectair system combined with
an electric compression-cycle air conditioner could provide a running cost reduction of
approximately 58% as compared to a reverse-cycle only system. Even greater savings
– approximately 80% – could be expected from a Solectair system with gas or reverse-
cycle electric boost as compared to resistive electric heating.

Table 1: Heating load and heating costs using Solectair, gas and electric heating for Perth Test
         House

Item
Calculated Heating requirements:
   Heating Requirements                                                    5013 kWh per year
   Heat supplied by Solectair HTS                                          3885 kWh per year
   Proportion of heat load supplied by Solectair                                 70%
Calculated Heating Costs:
   Cost to heat by ducted gas (75 MJ/h, 7.01 c/unit)                             $390
   Cost to heat by resistive electric (13.94 c/unit)                             $780
   Cost to heat by reverse-cycle electric (6.8 kW e, 20 kW h,
   COP = 3.0, 13.94 c/unit)
                                                                                 $390
   Cost to heat by Solectair (70% of heat load supplied)                          $60
   Cost to heat by Solectair with supplemental gas                               $170
   Cost to heat by Solectair with supplemental Reverse Cycle electric.           $170
Calculated Greenhouse Gas Emissions:
   Ducted Gas                                                                 1370 kg CO2
   Resistive Electric                                                         5010 kg CO2
   Reverse Cycle Electric                                                     1750 kg CO2
   Solectair only (70% of load)                                                320 kg CO2
   Solectair with supplemental gas                                             730 kg CO2
   Solectair with supplemental RC electric                                     840 kg CO2


The analyses also indicate that Solectair Heat Transfer System would be a cost
effective space heating option for most areas in Australia that require some level of
autumn, winter and spring heating. In many situations, the Solectair will provide 50% or
more of the annual heating requirements and, when used in conjunction with a back-up
or ‘boost’ heating system such as a gas or electric heater, would provide a cost-effective
means of achieving comfort during the colder times of the year. In some areas that
have higher levels of solar radiation but still require autumn, winter or spring heating
and/or where the building is of good thermal design, the Solectair could provide 100% of
a building’s space heating requirements.




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Solectair HTS Performance Estimations                                        DRAFT DOCUMENT

Background

This report is based on data collected during the preparation of an initial investigation
and report undertaken in 2002 (Performance Testing of Solectair Heat Transfer System,
Murdoch University, 2002). The data used in that initial report was collected from two
almost identical and adjacent houses in the Perth suburb of Mt Nasura from 1
September 2002 to 26 October 2002. During the 56-day period, 45 days of complete
data collected and 11 days of partial data were collected.

The two houses were of very similar construction, consisting of concrete slab-on-
ground, double-brick and clay tile and R2.5 bulk insulation on the ceiling (see Table 2).
The differences in design and construction were minor. One of the houses was fitted
with a Solectair Heat Transfer System while the other was not.

Table 2: Characteristics of the Perth Test House

                    Construction Type                                 Floor and Roof Areas
                                                                                                          2
  Walls               double clay brick (R0.53)             Total living space area            138.09 m
                                                                                                        2
  Roofing             ‘heritage red’ terracotta clay tile   Total house area                   183.36 m
                                                            (incl. carport, storeroom etc)
                                                                                                          2
  Floor               concrete slab-on-ground               Total roof area                    209.44 m
  Floor coverings     carpet, tiles, etc.
  Insulation          R2.5 bulk insulation in ceiling

The initial report found that while there were considerable differences in occupant
behaviour, the heating requirements for the two houses were very similar and therefore
provided a good basis for comparing the relative effectiveness of the heating systems.

The initial report concluded that:
“The HTS appears to work very well and over the test period collected a considerable amount of usable
heat. During the period, the amount of heat collected per day ranged from 0 up to about 100 kWh with an
electrical energy input of 1/10 to 1/20th of that delivered, making the HTS considerably better performing
than any fuel or electrical (including heat-pump and reverse cycle) heating system.

The peak daily power output ranged from 0 to about 20 kW and the average was 0 – 3 kW over a 24 hour
period. Obviously, the colour of the roof surface, the construction of the house, the actual design and lay-
out of the HTS and many other factors will influence the actual amount of heat energy collected from a
HTS and the results given are only for the particular system tested under the certain conditions
experienced during the test.”

The initial report concluded further that:
“In places such as Perth and most parts of the South-West of Western Australia and areas with similar
climatic conditions such as is found in most parts of Southern and South-Eastern Australia and in many
parts of the world with cool (rather than very cold) winter climatic conditions, the HTS, in combination with
houses of suitable design and construction, will undoubtedly perform very well. In many cases, the use of
a HTS will almost totally alleviate the need to use conventional gas, wood and electric heating in a house
and only the infrequent and short use of these may be needed.”

The aim of the present study was to use the data collected in the initial study in order to
undertake a more thorough analysis in order to estimate the performance of the
Solectair throughout a whole year and, if possible, to estimate the expected
performance of the System under the climatic conditions of various localities around
Australia.



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    2. Methodology

The data collected over a two-month period in the 2002 study was entered into a
spreadsheet, together with meteorological data for Perth for the two-month period. This
information was used to determine the conditions (ambient temperatures, hourly
average temperature, average monthly day-time temperature) under which the Solectair
operated, i.e. the ambient temperatures for which the Solectair fan turned was ‘on’.

Separate temperature measurements were obtained from a number of houses of similar
construction, but of differing roof colour to determine the impact of roof colour.

To determine the performance of the Solectair under different conditions, the following
procedure was used:

           I. All data was collected and assembled into a spreadsheet.

          II. The data was filtered according to different criteria, including:
                    i. level of solar insolation;
                   ii. level of solar insolation and the operation of the HTS fan;
                  iii. level of solar insolation, HTS fan operation and time of day;
                  iv. level of solar insolation, HTS fan operation, ambient temperature;
                   v. level of solar insolation, HTS fan operation, ambient and average
                       HTS house interior temperature; and
                  vi. level of solar insolation, HTS fan operation, ambient, average HTS
                       house interior and average control house temperature.

         III. Graphical and statistical analysis techniques were then used to examine the
              data, as ordered above, in order to determine important trends and
              relationships, such as the relationship between solar insolation, average
              ambient temperature and the average indoor temperatures of the control
              and the Solectair-equipped houses.

         IV. Once the above relationships had been determined, empirical equations
             were then derived in order to enable estimations to be made of the
             performance of the Solectair under various conditions. For example, an
             equation was derived to give the probability of the Solectair fan operating,
             i.e., usable heat being produced, under various conditions of solar
             insolation. An equation was also derived that gave the estimated heat
             output of the Solectair under differing solar insolation and ambient
             temperature conditions.

         V. Using the calculated probabilities of the Solectair fan operation and the
            estimated heat energy output of the system, the climatic conditions for Perth
            during a twelve month period and for other localities throughout Australia
            were then examined in order to determine the expected heat energy output
            of the system in a house similar to that of the test house.

         VI. Data from three houses of similar construction, but with different coloured
             roofs (light, medium and dark) was supplied to the author of this report.
             Using that data, estimations were made for Perth and for the different
             localities of the expected performance of the Solectair for a house similar to
             the test house in the different localities.



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        VII. Plans for the test houses were obtained and a housing heating and cooling
             simulation was then run using the ‘Ecotect’ building simulation software
             package. This gave the ‘baseline’ heating and cooling requirements for a
             house similar to that of the test house in the different locations.

       VIII. Empirical equations were derived, based upon the data collected during the
             2002 trials and from the calculated heating loads. These were then used to
             estimate the performance of the system over the year and the heating loads
             on a weekly basis.

         IX. Energy saving estimations and cost saving estimations were then calculated
             using the data collected from the test houses and the results of the
             performance calculations.

         X. Greenhouse gas emissions were calculated for the systems, based upon
            the energy usage of each system. Greenhouse gas intensity for the
            different energy sources was based upon the values given in ‘Energy WA
            2003’ (Office of Energy, Perth, WA, 2003)

         XI. The process was repeated for different locations using climatic data specific
             to those locations.


    3. Results and Discussion

Due to the large amount of information derived from the analysis, the results for Perth
are given in depth, but summary results only are provided for the other localities.


3.1 Estimation of the performance of the Solectair during data collection period

From the data, it was found that:
     the Solectair did not begin to operate effectively below an average ambient
        temperature of 16°C;
     the heat from the Solectair was no longer required once the hourly average
        temperature was above 24°C in Perth (To take into account the differing
        climates of the localities, a small range was allowed (±1°C).);
     the heat from the Solectair was no longer required once the average monthly
        day-time temperature was above 22°C for Perth (To take into account the
        differing climates of the localities, a small range was allowed (±1°C));

It was found that roof colour has a small impact on the performance of the Solectair
Heat Transfer System, with darker coloured roofs resulting in a higher heat output. This
was taken into account in the calculations and three sets of performance calculation
estimations (light, medium and dark roof surfaces) were performed.1



1
  Due to total yearly thermal performance considerations and depending on the local climatic conditions, it
is generally preferable for a building to have a light coloured roof surface than a dark roof surface. While
this may reduce the heat produced by the Solectair in the cooler times of the year, it also helps keep the
building cooling in summer, thereby minimising summer cooling requirements. This is generally
preferable to having a dark coloured roof surface, which may increase heat output of the Solectair HTS in
winter, but will also increase the cooling requirements in summer.

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Solectair HTS Performance Estimations                              DRAFT DOCUMENT

Trends and relationships between the relevant parameters were determined by
graphing the data collected over the two-month period and examining the curves
generated.

Graph 2 indicates the relationship between the solar irradiation and the average
ambient, house and HTS outlet temperatures.

 Graph 2: Relationships between solar irradiance (Wm-2) and (i) temperature of the HTS
 outlet duct (Temphtsoutlet in red), (ii) average HTS house room temperature (Temphtsaveroom in
 orange), (iii) average control house room temperate (Tempavectrroom in green) and taverage
 ambient temperature (Tempamb in blue).




From Graph 2 it can be seen that the average Solectair outlet air temperature was 10 to
15 C above the average ambient temperature and that the average Solectair test
house room temperature was 2 to 4 C higher than the average control house room
temperature. The results were skewed somewhat, however, by the fact that occupants
of the control house made frequent use of a 34 MJ gas heater. The differences between
the indoor temperatures of the Solectair and the control houses were therefore
significantly reduced and because of this, the results tend to understate the
performance of the Solectair

Graph 3 (over) shows the relationship between the time of day and the ambient and
average room temperatures during the monitoring periods. The periods in which the fan
of the Solectair was on (i.e. the Solectair was transferring heat) are indicated by ‘peaks’
in the daytime average room temperatures curves.




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Solectair HTS Performance Estimations                                   DRAFT DOCUMENT



    Graph 3: The data plotted showing the relationship between the average room temperatures
    and ambient temperatures of the two houses and the time of day. Also shown is the
    temperature ambient outside temperature in green and the roof-space temperature in pink.




It is apparent from Graph 3 that the times at which the Solectair fan operated was
dependent on the level of solar insolation and that this heat would normally be available
only during day-time.2 Furthermore, while morning and afternoon solar irradiation
curves were generally symmetrical, the Solectair operated differently in the morning
periods to the afternoon periods. In the morning, while the levels of solar irradiance may
be quite high, the ambient temperature and the roof-space temperatures may be quite
low. On the other hand, in the afternoon, while the solar irradiance may be similar to
that of the morning periods, the roof-space temperature is generally higher. In August,
for example, the average ambient temperature for Perth at 9:00 (three hours prior to
noon,) is on average 13.6C and the solar irradiance is about 250 Wm-2. At 15:00 (three
hours after noon), the solar irradiance is similar to that at 9:00, but the average ambient
temperature is approximately 16.3 C.

Graph 4 (over) is a plot of the morning and afternoon operation of the fan (in percent of
time) versus temperature. Logging intervals were ten minutes in duration. A ‘0%’
condition indicated that during the 10 minute logging interval, the fan was not on, while
a ‘100%’ condition indicated that the fan was on for the entire 10 minute period. A
fractional value indicates that the fan was on for that proportion of the 10-minute
interval. For example, a 60% condition indicates that the fan was on for a total of 6
minutes of the 10 minute logging interval.

It can be seen from Graph 4 that regardless of solar irradiance, the Solectair fan did not
turn on until the temperature reached approximately 16C. The fan turned off whenever
2
 On a few occasions, the fan came on in the early evening after sunset. This occurred as there was
sufficient heat stored in the roof structure, the air in the roof space was at a temperature above the
minium set-point, and the household room temperature is below the minimum set-point.

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Solectair HTS Performance Estimations                            DRAFT DOCUMENT

there was insufficient solar radiation to maintain a roof-space temperature sufficiently
high to provide usable heat. This occurred at night, in the early morning or afternoon,
and during very overcast conditions.

  Graph 4: Fan ‘on’ and ‘off’ temperature requirements.




Graph 5 shows the fan Run-Time probabilities for AM and PM versus solar irradiance.

  Graph 5: AM and PM Fan On probabilities versus solar irradiance levels.




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The ‘fan-on’ probabilities (i.e. the proportion of time that the fan was on) were also
dependent on the level of solar irradiance. Examining and comparing the incidences of
fan operation against the solar irradiance determined these probabilities. The morning
and afternoon performances of the system differed due to the non-symmetrical
temperature conditions around mid-day (and also allowing for the 16 minute difference
between WA Standard time and Perth Local Solar Time).

Graph 5 shows that at a solar irradiance level of between 300 and 400 Wm -2 during the
AM period, the probability of the fan being on and producing usable heat is about 9%.
During the afternoon period, however, the probability that the fan is on for a solar
irradiance level of 200 – 300 Wm-2 is about 40%. Above solar irradiance levels of
~1100 Wm-2, the probability that the fan will be on is ~ 100%, regardless of the ambient
temperature.3


3.2 Estimation of the performance of Solectair over a twelve-month period

Meteorological data and collected performance data for Perth was used to extrapolate
the Solectair heat output for a twelve-month period. The meteorological data used was
the hourly average temperature for each month and the hourly average solar irradiance
(MJ/m-2) for each month. This data was obtained from a variety of sources, including
the Australian and New Zealand Solar Energy Society’s (ANZSES) AUSOLRAD solar
irradiance database, Bureau of Meteorology data, Square One ‘Weathertool’ (University
of Western Australia and University of Cardiff), and the US Department of Energy.

Graph 6 shows the estimated run-times for the Solectair against average monthly
temperature and average monthly solar irradiance.

    Graph 6: Calculated Solectair fan operation probability for the whole year in Perth.




3
  Of course if the room temperature is already high enough, the controller may provide an over-ride signal and the
fan will not operate.

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Graph 6 indicates the probability that the Solectair will be providing heat for different
times during the year. At approximately 13:30 in early June, for example, the probability
of the system being able to provide usable heat is 50 – 60%. The usefulness of the
information in Graph 6 however, is limited by the fact that it does not take into account a
number of other important factors, such that a minimum ambient temperature of ~16 C
is required before the Solectair fan will switch on and provide usable heat.

Graph 7 shows the result when the data is limited to times when the minimum ambient
temperature is over 16C and a maximum ambient4 temperature is 24C or less. The
fact that many houses are unoccupied during most of the daytime was not taken into
account in the calculations and allowing for a higher interior set-point temperature
during the day would allow more heat to be stored in the thermal mass of the house and
would improve significantly the estimated total performance of the Solectair system.

    Graph 7: Calculated Solectair fan operation probability for the whole year in Perth when the
    minimum daily average temperature is greater than 16 C and less than 24 C.




The usefulness of Graph 7 is also limited in that it does not take into account the fact
that there is generally no requirement for domestic heating during the warmer times of
the year (Summer and parts of Autumn and Spring).

Graph 8 (over) shows the results if it is assumed that most houses of similar
construction to the Test House would not require heating when the monthly average
day-time ambient temperature was above 22C.

It was expected that the performance of the Solectair would be dependent on a number
of other factors, including the house design and construction, wind speed and air mass
leakage from the roof-ceiling space and the absorptivity of solar radiation of the roofing
material. Using separate test result data supplied by Mr Kim Dartnall of Solectair Pty
Ltd, it was found that the temperature limits for a ‘dark’ coloured roof were about 1.2C
lower and that for ‘light’ coloured roof surfaces, the limit were increased by about 2C. It


4
    The 24° C set-point was chosen as when the maximum ambient temp. is >24° C, heating is usually not needed.

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Solectair HTS Performance Estimations                               DRAFT DOCUMENT

needs to be borne in mind that in addition to roof colour, other variables exist and that
actual performance will vary from house to house due to those factors.
  Graph 8: Calculated Solectair fan operation probability for the whole year in Perth when the
  minimum daily average temperature is greater than 16 C and less than 24 C and the
  daytime average daily temperature is less than 22 C.




Graphs 9 and 10 indicate the calculated ‘fan on’ probability for a house of the same
design and climatic conditions as that of the test house, but with a ‘light’ coloured and a
‘dark’ coloured roof surface, respectively.

  Graph 9: Calculated Solectair fan operation probability for a light coloured roofed house for
  the whole year in Perth when the minimum daily average temperature is greater than 16  C
  and less than 24 C and the day-time average daily temperature is less than 22 C.




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Solectair HTS Performance Estimations                              DRAFT DOCUMENT


  Graph 10: Calculated Solectair fan operation probability for a dark coloured roofed house.
  The limits are the same as for Graph 8.




It was found that the air mass flow was 1.3 kgs-2 for the Solectair installed on the test
house in 2002. Given the specific heat of air (~1.007 kJkg-1C-1), and using the
probability data presented above, the energy obtainable from the Solectair can be
estimated for any time of the year. Using the limits stated above, the data presented in
Graphs 11, 12 and 13 was derived. These show the estimated annual heat output for a
light coloured, medium coloured and dark coloured roofs on houses of design and
construction similar to that of the test house. In commercial situations, as opposed to
domestic situations, other heating regimes may apply and the actual heat output may be
higher or lower.

 Graph 11: Calculated Solectair fan heat output for a light coloured roofed house. Limits are
 those detailed above.




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  Graph 12: Calculated Solectair fan heat output for a medium coloured roofed house.
  Limits are those detailed above.




  Graph 13: Calculated Solectair fan heat output for a dark coloured roofed house. Limits
  are those detailed above.




The increased quantity of heat produced with darker coloured roof surfaces can be
readily seen.




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3.3 Estimation of total annual heating load and fraction of heating load supplied
    from Solectair

In order to determine the heating load for the test house, a simulation of the house was
run using building simulation software. Detailed architectural plans of the Perth
Solectair Test House were obtained and the appropriate data entered together with the
average hourly meteorological data for Perth.

Figures 1, 2 and 3 (over) show screen capture images of the test house as entered into
the simulation software.

After the relevant information, including building layout, construction materials,
insulation, building orientation, etc., was entered, the energy simulations were run. The
main assumption used in the simulations was that the temperature of the living area of
the house did not fall below 18C. The simulations were then re-run using the same
building layout, construction, etc, except that the building was then ‘located’ in a number
of alternate Australian cities using meteorological data relevant to each city.

It must be noted that building design and construction does vary from state to state in
Australia. The majority of houses in Western Australia are constructed of concrete slab-
on-ground, cavity-wall brick (double-brick with a cavity), plasterboard ceiling, and tiled or
metal sheeting roof. Internal walls are usually single brick, with plaster or cement
render. Usually the only insulation is on the ceiling or under the roof. In most other
Australian states, house construction is typically brick-veneer (single-brick with internal
cladding) and internal walls are usually plasterboard (with cavity) or single brick.

The Test House was of typical Western Australia construction and the building
simulation for heating load was based upon this design only, even for the other
localities.

To address possible differences between the thermal load differences between cavity-
brick and brick-veneer houses, a simulation was run with the exterior walls changes to
brick veneer. It was found that the heating load increased by less than 5%. Such a
small change is due to the insulating properties of cavity-brick and brick veneer being
very similar: approximately R0.53 for cavity-brick and R0.51 for brick veneer.

A simulation was also run to address the issue of different internal walls. The interior
walls were changed from plaster rendered single-brick to framed timber with
plasterboard. This increased the heating load by a further 9%, thus raising it from 5013
kWh in a year to about 5700 kWh.

It was felt that this relatively small increase in heating load would not significantly affect
the performance of a Solectair and the yearly net heating load provided by a Solectair
would be similar for houses of similar layout but with the two different construction
methods listed. Furthermore, it should be remembered that in many states of Australia,
the typical levels of insulation used are higher than those in Western Australia. Thus a
typical eastern states brick-veneer house with more insulation may perform better than
a typical Western Australian cavity-brick house.




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   Figure 1, 2 & 3: Screen capture images of the test house as entered into the simulation software.




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The results of the Perth simulation run are shown in Table 3 and Graph 14.

Table 3:        Calculated Perth heating and cooling simulation results.
                Minimum temperature= 18 C, maximum temperature = 26 C.
                         MONTH          Heating (kWh/mth)   Cooling (kWh/mth)
                           Jan                   0                 239
                           Feb                   0                1144
                           Mar                   0                 123
                           Apr                 106                   0
                          May                  491                   0
                           Jun                1209                   0
                           Jul                1446                   0
                           Aug                 961                   0
                           Sep                 663                   0
                           Oct                 138                   0
                           Nov                   0                 192
                           Dec                   0                 159
                          Total               5013                1857



 Graph 14: Calculated heating load for Solectair Test House.




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3.4      Estimation of the Performance of the Solectair for other localities in
          Australia.

Similar results were produced for other Australian localities and Table 4 and Graph 15
gives the yearly total heating and cooling loads for these localities. These results are
representative of the locations and while any actual heating load may vary from those
calculated, depending on user requirements and behaviour, with all other factors being
equal, they do indicate the relative differences between localities.

Table 4: Calculated heating and cooling simulation results for Solectair Test House in different
  Australian Localities. Minimum house temperature= 18C, maximum temperature = 26C.

                                        Heating (kWh/y)   Cooling (kWh/y)
                        Adelaide             9,384             1,374
                        Albany              10,024               49
                        Brisbane             2,751             1,218
                        Canberra            20,031                0
                        Geraldton            3,911             3,336
                        Hobart              14,863                0
                        Kalgoorlie           6,855             5,676
                        Melbourne            8,691              601
                        Mildura             11,298             4,606
                        Perth                5,013             1,857
                        Richmond             6,785             1,000
                        Sydney               5,160              281
                        Tamworth            11,156              558
                        Whyalla             10,265              564




 Graph 15: Calculated heating and cooling loads for the Solectair Test House in different
 Australian localities.




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As the performance of the Solectair increases with both average ambient temperature
and level of solar irradiance, the peak performance of the Solectair does not occur
during periods of maximum heating requirement. The Solectair can generally provide
sufficient, or even excess heat, during the ‘shoulder’ periods of autumn and spring, but
may not be able to provide all of the heating requirements during winter, depending on
the actual location, the building and the specific heating requirements. In such situation,
supplemental heating may be needed.

The amount of any supplemental heating needed was calculated by subtracting the
amount of heat produced by the Solectair from the calculated heating load.

Graph 16 shows the calculated weekly heating load and the calculated heat output from
the Solectair for the Perth Test House. In order to simplify the calculations, the
distribution of the heating load was assumed to be Log-Gaussian. The error between
the calculated heating load using the building simulation software and the simplified
Log-Gaussian distribution was found to be less than 1%.

  Graph 16: Calculated weekly heating load and the calculated heat output from the Solectair
  for the Perth test house.




As heating is not usually necessary during the warmer times of the year, Graph 16
needs to be truncated to exclude these periods. Doing so gives the (smoothed) curves
shown in Graph 17 (over). The area of the underlying red curve represents the heating
load, while the orange area overlaid shows the portion of the heating load that the
Solectair is able to provide. The visible red area, therefore, is the portion of the heating
load that the Solectair is unable to provide.




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Solectair HTS Performance Estimations                            DRAFT DOCUMENT



  Graph 17: Heating load and useable heat produced by the Solectair.




Over the whole heating period, the Solectair is able to provide approximately 70% of the
total heating requirements for the Test House. The proportion of the total heating load
that the Solectair will be able to provide will, of course, vary from one house to another
and from location to another. It will also depend on occupant behaviour. In the case of
the Solectair test house, there was only one occupant and a number of rooms were only
infrequently used. As the doors to those rooms were usually left closed, the effective
area that requiring heating was less than was the case in the control house were there
were two occupants who made more use of their house. Had the Test House had two
occupants, the Solectair would probably have provided 50 – 60% of the heating
requirements, rather than the calculated 70%.

During the coldest period in late July, the output of the Solectair in the Perth Test House
falls to about 28% of the heating requirements (averaged over the week). In order to
keep the house in a comfortable temperature range during that period, supplementary
heating would therefore be necessary.


           I. Cost Comparisons.

Calculations were undertaken to allow a cost comparison between the Solectair and
other common forms of heating, including ducted gas (normally combined with an
evaporative air-conditioning system) and reverse-cycle electric heating. As the
Solectair is also normally combined with a ducted air-conditioning system, usually
evaporative but with ducted reverse-cycle is also possible, these have been used as the
basis for comparisons.

In addition to the previous assumptions of building design and construction, heating
loads, etc., the following assumptions were made for the purposes of cost calculations:

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   ●      the cost of gas was priced at 7.01 c/kWh. Supply charges, connection fees,
          etc., were not included in the calculations;
   ●      the efficiency of the ducted gas system was assumed to be 85%;
   ●      the cost comparisons for gas are based upon a 75 MJ/h (21 kW) ducted gas
          system with a 600 W blower;
   ●      the cost of electricity was priced at 13.94 c/kWh. Supply charges connection
          fees, etc., were not included in the calculations;
   ●      the Coefficient of Performance for the reverse-cycle air conditioning cost
          comparison was assumed to be 3.0:1. This is the average of the 540 reverse-
          cycle ducted air-conditioning systems listed on the AGO Energy Star Rating
          WWW (September 2004) site; and
   ●      it was assumed that the size of the ducted reverse-cycle air-conditioner system
          was 6.8 kW e, that the heat output was 20 kW h and that the fan system consisted
          of two 375 W blowers.

Table 5 and Graph 18 give the results of the cost comparison calculations.
Table 5: Heating cost summary for Solectair Test House.
       Monthly                                             Heating costs
                Solar Heating Heating costs Heating costs                   Solectair   Solectair Solectair
        Heating                                                 with
Month           from Solectair with Natural with electric                    running    + Natural   + RC
         Load                                              reverse-cycle
                  (kWh/mth)      Gas ($)     resistive ($)                  costs ($)    Gas ($) Electric ($)
      (kWh/mth)                                              electric ($)
 Jan       0          0             0              0              0            0           0          0
 Feb       0          0             0              0              0            0           0          0
 Mar       0          0             0              0              0            0           0          0
 Apr       42         42            5              6              3            1           1          1
 May      558        558            47            86             43            8           8          8
 Jun     1302        866            92           202            101            6          40          40
 Jul     1439        495            56           223            111            3          76          77
 Aug      986        879            72           153             76            8          16          16
 Sep      484        484            49            75             37            10         10          10
 Oct      174        174            12            27             13            13         13          13
 Nov       28         28            1              4              2            2           2          2
 Dec       0          0             0              0              0            0           0          0
Total 5013 kWh 3526 kWh            $387         $776            $387          $51        $165        $167

 Graph 18: Estimated monthly cost comparisons between different heating systems: Resistive
 electric, ducted gas, reverse-cycle electric air-conditioning, Solectair only, Solectair with gas,
 Solectair with RC electric.




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Graph 18 shows the calculated monthly heating cost for a number of different systems.
Usually there are no heating requirements or costs in a domestic situation in the warmer
times of the year, but as the winter season approaches, the heating requirements, and
hence cost, increase before decreasing again as the weather warms.

It can be seen that the running costs (shown in yellow) for the Solectair-only heating
system is almost negligible. In some situations, however, the Solectair-only system
may not provide sufficient heat to maintain the indoor house area at a comfortable
temperature during parts of the heating season, depending on the user requirements,
the climate and the house design and construction. In such situations, supplementary
gas or electric heating may be needed. These are illustrated by the orange and gold
curves in Graph 18.

The dark blue-purple curves indicate the cost to produce 5013 kWh using simple
electric resistive heating, such as bar radiators or oil-filled radiators. The mid-blue
curves show the estimated heating using a 6.8 kW electrical reverse cycle air-conditioning
system with a heat output of 20 kW heat (COP = 3.0:1). The mauve curve indicates the
costs of using a 75 MJ/h (21 kW) ducted gas system.

Using meteorological data for other Australian localities, a similar procedure was used
to calculate the expected heat production and cost savings for those other localities.
These are shown in Section 5.

Table 6 shows the approximate monthly and yearly total cost comparisons for
    (i) a Ducted Gas only system vs. a Solectair plus Gas System;
    (ii) a Electric Reverse Cycle Air-conditioning system vs. a Solectair plus a
          Reverse Cycle Air-conditioning system; and
    (iii) an Electric Resistive vs. a Solectair plus Gas or electric RC.

The yearly saving is approximately $222 in the first case and $220 for the second. As
the retail price of the Solectair is approximately $600 when purchased as a complete
air-conditioning package from the suppliers (in conjunction with a ducted air-
conditioning (cooling) system), the financial payback period is 2 to 3 years. Compared
to electric resistive heating, the annual saving is over $600, giving a payback of
approximately one year.

Table 6: Approximate cost savings of a Solectair = Gas system vs. a gas only system and a
Solectair + reverse cycle electric system vs. a reverse cycle only system.
              Cost saving ($) - Gas vs.   Cost saving ($) - Electric RC vs.   Cost Saving ($) Electric Resistive vs.
   MONTH
                  Solectair + Gas                 Solectair + RC                     Solectair + Gas or RC
     Jan                 -                                -                                      -
     Feb                 -                                -                                      -
     Mar                 -                                -                                      -
     Apr                 2                               2                                      5
    May                 36                               36                                     79
     Jun                61                               60                                    162
     Jul                35                               35                                    146
     Aug                60                               60                                    137
     Sep                27                               27                                     65
     Oct                 1                               1                                      14
     Nov                 -                                -                                     2
     Dec                 -                                -                                      -
    Total              $222                             $220                                  $610




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Solectair HTS Performance Estimations                                                   DRAFT DOCUMENT

        II. Greenhouse Gas Emissions
Table 7 lists the greenhouse gas emissions for the comparison electric resistive heater
system, ducted gas system, reverse-cycle air-conditioner, Solectair only system,
Solectair with gas assist and a Solectair with reverse-cycle air-conditioner assist. In all
cases (with the exception of the Solectair-only case), the values in are for the systems
to supply 5013 kWh of heat as per Table 3. In the Solectair-only case, the heat
supplied is 3526 kWh. The data is shown graphically in Graph 19.

Table 7: Greenhouse Gas Emissions for different heating systems.
          Resistive electric Ducted Gas        RC Electric Solectair Only Solectair + Gas Solectair + RC Electric
MONTH
              (kgCO2)         (kgCO2)           (kgCO2)       (kgCO2)        (kgCO2)             (kgCO2)
  Jan             0                 0          0                     0                 0                     0
  Feb             0                 0          0                     0                 0                     0
  Mar             0                 0          0                     0                 0                     0
  Apr             28                8         10                     9                 9                     9
  May            492              139        176                    49                49                     49
  Jun           1260              348        443                    39               158                    191
  Jul           1458              399        509                    18               277                    349
  Aug           1029              280        358                    50                80                     88
  Sep            519              140        180                    65                65                     65
  Oct            192               52         66                    82                82                     82
  Nov             35                9         12                    15                15                     15
  Dec             0                 0          0                     0                 0                     0
  Total      5010 kgCO2        1375 kgCO2 1755 kgCO2            326 kgCO2         734 kgCO2              847 kgCO2


The use of the Solectair, either alone or in conjunction with boost heating, in place of
stand-alone gas or reverse-cycle electric heating results in significant greenhouse gas
(GHG) emissions reductions. For a house similar to the Solectair Test House, the
addition of a Solectair to a ducted gas heating system could reduce the emissions by as
much as 53%, and by 48% compared to a reverse cycle air-conditioner. Compared to
simple resistive heating, the GHG emission reductions are between 83 and 94%.
 Graph 19: Greenhouse Gas Emissions from different heating systems to supply 5013 kWh
 (3855 kWh for Solectair only System).




 Emission values of 0.9 kgCO2/kWh for electricity and 0.185 kgCO2/kWh for natural gas. Based on data from ‘Energy WA 2003’
                                                   - 23 -
Solectair HTS Performance Estimations                                                          DRAFT DOCUMENT

    4. The Performance of the Solectair in Other Locations

Based upon the results obtained for the test houses in Perth and correlating these
against meteorological data, estimations were made of the performance of the Solectair
system for several other locations around Australia.

The estimations were then compared with the calculated heating loads for a house
identical to the Solectair Test House, but located at different locations around Australia.
The results took into account local meteorological conditions for each locality and were
generated using the Ecotect building simulation software package. As with the Perth
calculations, in order to simplify the procedure, empirical equations were determined to
match the heat load and Solectair potential profiles. Log-Gaussian, Gaussian or
polynomial equations were used, depending on which most closely matched the load or
Solectair potential profile. The load calculations are given in Table 8.

Table 8: Heating load calculations for different localities around Australia.
                              Yearly Heating Load       Solar Heating from          Percentage of Yearly Heating Load
              Location
                                    (kWh/y)              Solectair (kWh/y)                Supplied by Solectair
           Adelaide                   9410                      3710                                 39
           Albany                    10220                      3120                                 31
           Canberra                  19970                      2550                                 13
           Brisbane                   5270                      3870                                 73
           Melbourne                 13590                      5430                                 40
           Perth                      5020                      3530                                 70
           Sydney                     5270                      3870                                 73


Based upon these results, the cost of meeting the heating load in each location was
calculated, taking into account the relevant electricity and natural gas (or LPG where
appropriate) prices for the particular location. Supply charges, etc., were not included in
the calculations. The results are presented in Table 9. It should be noted that the costs
given in the ‘Solectair-only ($)’ column are for the energy produced only as listed in the
‘Solar Heating from Solectair (kWh/mth)’ column of Table 8. That is, the costs are for
the energy collected by the Solectair and not for the total required load. For example,
for Adelaide the ‘Solectair-only’ system would supply, under the test criteria, about 3710
kWh, or 39% of the total annual heating load. The cost for this would be approximately
$60 per year and would be due to the electricity needed to run the Solectair fans and
control system, etc. To provide the full heating load of 9410 kWh, additional or ‘boost’
heating would be required to meet the shortfall of 5700 kWh. In the case of a Solectair
with ducted natural gas, the total cost of meeting the heating load would be $490: $60
for the solar fraction of 3710 kWh and $430 for the remaining 5700 kWh natural gas
fraction.

Table 9: Estimated running costs for different heating methods to supply the heating loads
presented in Table 8.
                   Ducted Natural     Electric      Reverse-cycle                           Solectair + Natural   Solectair + RC
  Location                                                             Solectair only ($)
                      Gas ($)       resistive ($)    electric ($)                                Gas ($)           Electric ($)
Adelaide                720            1850             930                   60                   490                 620
Albany*                1480            1590             790                   20                   1050                580
Canberra               2160            3330             1660                  20                   1900               1490
Brisbane                350             730             360                   20                   110                 120
Melbourne               620            2530             1260                  30                   400                 790
Perth                   390             780             390                   60                   170                 170
Sydney                  350             730             360                   20                   110                 120
* Gas price for Albany is based upon bottled LPG, not natural gas.

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Solectair HTS Performance Estimations                                                     DRAFT DOCUMENT

Table 10 provides the cost in cents per kWh. These figures are based upon the heating
load for the location and the gas and/or electricity tariff for the location in question. It
can be seen from Tables 10 that the cost per kWh for the heat provided by the Solectair
is between ¼ and 1/30th of the cost of the heat provided by the conventional heating
methods.

Table 10: Estimated cost (cents per kWh) for the different heating methods to supply the
heating loads presented in Table 8.
               Ducted Natural   Electric resistive    Reverse-cycle      Solectair only   Solectair + Natural    Solectair + RC
  Location
                Gas ($/kWh)         ($/kWh)          electric ($/kWh)       ($/kWh)          Gas ($/kWh)        Electric ($/kWh)

Adelaide            7.7                19.7                   9.9             1.6                5.2                  6.6
Albany             14.5                15.6                   7.7             0.6                10.3                 5.7
Canberra           10.8                16.7                   8.3             0.8                9.5                  7.5
Brisbane            6.6                13.9                   6.8             0.5                2.1                  2.3
Melbourne           4.6                18.6                   9.3             0.6                2.9                  5.8
Perth               7.8                15.5                   7.8             1.7                3.4                  3.4
Sydney              6.6                13.9                   6.8             0.5                2.1                  2.3


From Tables 9 and 10 it can also be seen that there is a considerable cost saving when
a Solectair system is used in conjunction with a ‘traditional’ heating system that is used
as a back-up or boost heater. Table 11 gives the estimated cost saving of a combined
system as compared to a ‘stand-alone’ ducted gas, reverse cycle or resistive heating
system. More specifically, the three costs comparisons are for
  (i) a Solectair + natural gas system versus a natural gas only system;
  (ii) a Solectair + reverse-cycle electric system versus a reverse-cycle electric only
        system; and
  (iii) a Solectair + reverse-cycle electric system versus a resistive electric only
        system.

Table 11: Estimated cost saving comparison.
                      Solectair + natural gas vs.      Solectair + reverse-cycle electric Solectair + reverse-cycle electric
        Location
                          natural gas only                vs. reverse-cycle electric            vs. resistive electric
  Adelaide                       32%                                    33%                              66%
  Albany*                        29%                                    73%                              64%
  Canberra                       12%                                    90%                              55%
  Brisbane                       69%                                    33%                              84%
  Melbourne                      35%                                    63%                              69%
  Perth                          56%                                    44%                              78%
  Sydney                         69%                                    33%                              84%
* Gas price for Albany is based upon bottled LPG, not natural gas.

Generally speaking, the warmer the climate, the lower the heating load, but the better
the Solectair performs. In places with milder climates, such as Brisbane, Perth and
Sydney, the Solectair system would be able to provide the majority of the yearly heating
load and this would achieve a substantial cost reduction over traditional gas or electric
only heating systems. It is quite probable that in such locations most, if not all, of the
heating requirements of a well-designed and well-insulated house could be provided by
a Solectair System.

Table 12 gives the estimated greenhouse gas emissions, in carbon dioxide equivalent,
produced using the different heating modalities to provide the heating requirements
given in Table 8.


                                                     - 25 -
Solectair HTS Performance Estimations                                                    DRAFT DOCUMENT

Table 12: Estimated greenhouse gas emissions produced using different heating modalities to
          provide the heating requirements given in table 6.
               Resistive electric     Ducted Gas   RC Electric   Solectair only   Solectair + Gas Solectair + RC Electric
  Location
                 (kgCO2/year)        (kgCO2/year) (kgCO2/year)   (kgCO2/year)      (kgCO2/year)       (kgCO2/year)
Adelaide             9400                  2570       3290             270              1830                 2260
Albany*             10210                  2800       3570             110              2060                 2600
Canberra            19960                  5470       6990             110              4890                 6210
Brisbane             5260                  1440       1840             110              500                   600
Melbourne           13580                  3720       4750             110              2350                 2970
Perth                5010                  1370       1750             320              730                   840
Sydney               5260                  1440       1840             110              500                   600
* GHG emissions from gas for Albany are based upon LPG, not natural gas.

Table 13 gives the estimated saving (comparison) in greenhouse gas emissions, in
kilograms of carbon dioxide per year for:
    (i)   a Solectair + natural gas system versus a natural gas-only system;
    (ii)  a Solectair + reverse-cycle electric system versus a reverse-cycle electric-
          only system; and
    (iii) a Solectair + reverse-cycle electric system versus a resistive electric-only
          system.

Table 13: Kilograms of CO2 reductions per year.
                      Solectair + natural gas vs.    Solectair + reverse-cycle electric Solectair + reverse-cycle electric
        Location          natural gas only              vs. reverse-cycle electric            vs. resistive electric
                            (kgCO2/year)                       (kgCO2/year)                       (kgCO2/year)
   Adelaide                         740                            1030                               7140
   Albany*                          740                             970                               7610
   Canberra                         580                             780                              13750
   Brisbane                         940                            1240                               4660
   Melbourne                        1370                           1780                              10610
   Perth                            640                             910                               4170
   Sydney                           940                            1240                               4660
* GHG emissions from gas for Albany are based upon LPG, not natural gas.

Table 14 presents the figures given in Table 13 comparison as a percentage. It can be
seen that the greenhouse gas emissions for a combined Solectair and gas or Solectair
and reverse-cycle electric system are considerable. Even in locations where the
proportion of the total heating load that can be provided by a Solectair may be relatively
low, the greenhouse gas emission reductions may still be very high and, in fact, may be
greater than in locations where the proportion of the total heating load that can be
supplied by the Solectair is relatively high.

Table 14: Kilograms of CO2 reductions per year as a percentage – Solectair Systems (with
boost) versus natural gas and electric only systems.
                      Solectair + natural gas vs.    Solectair + reverse-cycle electric Solectair + reverse-cycle electric
        Location
                          natural gas only              vs. reverse-cycle electric            vs. resistive electric
   Adelaide                         29%                            31%                                76%
   Albany*                          26%                            27%                                75%
   Canberra                         11%                            11%                                69%
   Brisbane                         65%                            67%                                89%
   Melbourne                        37%                            37%                                78%
   Perth                            47%                            52%                                83%
   Sydney                           65%                            67%                                89%
* GHG emissions from gas for Albany are based upon LPG, not natural gas.



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Solectair HTS Performance Estimations                          DRAFT DOCUMENT

    5. Summary and Conclusions

The estimations of the performance of the Solectair Heat Transfer System for Perth and
for other locations are based on data gathered over a two-month period in 2002 using a
house located in Perth in which a Solectair had been installed and an adjacent and
similar control house that did not have a Solectair System. Using average hourly
meteorological data and comparing the data from the test house and the control house,
the results were extrapolated to obtain a comparison over a full twelve-month period.
Similarly, using meteorological data from other locations, the performance of the
Solectair Heat Transfer System was interpolated for other locations.

The results of the analyses need to be treated with some caution for a number of
reasons: the data was collected over a two month period only; the differences between
the test and the control houses (the number of occupants; the use of gas heating in the
control house would have had some impact on the analyses; and the results have been
extrapolated for a full twelve month period and to other locations using available
meteorological data. Despite these limitations, the results are considered to provide a
relatively good estimation of the performance of the Solectair.

The results of the analyses and calculations indicate that, under Perth conditions, a
Solectair Heat Transfer System would be able to provide approximately 70% of the
home heating requirements over the heating season. The proportion of the heating load
that could be provided by the Solectair ranges from 100% during the early-autumn and
late-spring periods to about 30% during mid- to late-winter. The annual costs of heating
a typical house in Perth using a ducted natural gas heating system was estimated to be
$387, while the estimated cost to operate a Solectair in combination with a gas system
would be approximately $165, a saving of $222 per year. The annual costs of heating a
typical house in Perth using a ducted reverse-cycle heating system was also estimated
to be $387, while the estimated cost to operate a Solectair in combination with a
reverse-cycle system would be approximately $167, a saving of $220 per year.
Compared to resistive heating, a Solectair would provide even greater savings of
approximately $600 per year. Thus the financial pay-back period associated with
installing a Solectair would be between 1 and 3 years, depending on which system it is
compared to.

The effectiveness of a Solectair would depend on a number of factors, the principal
factors being the house construction and design and the local climate. The installation
of a Solectair would appear to be definitely cost effective for new houses in those
climates where, and for those house for which, the Solectair was able to provide all or
most of the annual space heating load. However, the results of the analyses also
strongly suggests that the installation of a Solectair would be cost-effective in many
situations where a gas or electric heating system is already installed, as the reductions
in running costs would mean that the costs of the Solectair system would be recovered
in only 1 to 3 years.

The cost-effectiveness of the Solectair in other locations apart from Perth will depend on
the climate and the existing heating system. It is clear, however, that in most situations
in mainland Australia that the installation of a Solectair would be a cost-effective space
heating option.

As well as reducing the running costs of a gas-only or electric-only heating system, the
use of Solectair would also reduce greenhouse gas emissions associated with space

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Solectair HTS Performance Estimations                         DRAFT DOCUMENT

heating in domestic and light commercial applications by between 600 and 1000 kg per
year, or by approximately about 50%, when compared to the greenhouse gas emissions
produced when using gas only or reverse-cycle electric space heating systems.
Compared to a resistive electric heating system, the greenhouse gas emission
reductions achieved by using a Solectair system would be over 4000 kg of emission
reductions per year. Even in those where the Solectair only provided a relatively small
proportion of the total heating requirements due to the high heating loads, it was found
that very significant emission reductions could also be achieved.




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