Hot water solutions for a changing climate

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Hot water solutions for a changing climate Powered By Docstoc
					Solar thermal
And its integration with
commercial and industrial hot
water systems
Lochinvar Ltd
Steve Addis – L.Z.C product manager
Our company

In the UK since 1976
Relocated to new
headquarters in 1998

                       Lochinvar corporation started
                       in 1919
                        2001 relocated to 360,0002ft
                       Major player in high
                       efficiency water heater &
                       boiler industry in USA
Basic system design

Designing a solar thermal system

System components

Sizing solar systems

Integration with DHW systems
System components

A solar thermal DHW system requires:

A solar collector
Storage vessel or heat exchanger
Pipe work
Control system
Primary heat source
System components

There are 2 main types of solar collectors

Flat plate

Evacuated tube
Solar collectors Pros

Flat panel                 Evacuated tube
• Simple design            • Higher efficiency on low
• Long warranties            irradiation days
• Better at handling       • Smaller surface area?
       stagnation          • Lighter?
• Cheaper                  • Repairable
• Can be roof integrated
• Better looking?
Solar collectors Cons

Flat panel                Evacuated tube
• Can be Heavier          • Seen as delicate
• Larger surface area     • Can need higher
   required?                maintenance
• Less efficient on low   • Will overheat readily if
   Irradiation days         stagnation occurs
Solar collectors
Lochinvar G1000-10 flat
plate collector
Solar collectors
Lochinvar G1450-10 flat
plate collector
Solar collectors
Lochinvar CPC Evacuated tube
Solar collectors
Evacuated tube collector principles
Solar collectors

All solar collectors must be certified to BSEN 12975

Look for the solar key mark

The Key to grants
Collector efficiency

Collector efficiency consists of:

Absorber efficiency (average 75%)
Minus absorber emissions 2%-14% (dependant
upon insulation and selective coating)
This will be shown as A1/A2 heat loss coefficient

Collector efficiency will change according
    to t between collector fluid
         temperature and outside air
Collector efficiency
Collector efficiency

Care should be taken to ensure the collectors are sited

South facing - 30-40 degrees inclination

Avoid shading
Collector Efficiency

Chart showing the effects of varying the inclination and
azimuth of collector field
      Inclination    South    SE/SW   E/W   NE/NW   N

      Horizontal                      933

         30o         1042      997    886    762    709

         45o         1023      968    829    666    621

         60o          960      900    753    580    485

       Vertical       724      684    565    427    360
Solar collectors

Roof integration can be difficult on commercial buildings

Architects/structural engineers need to be involved at
  design stage

Need to think about maintenance and possible future
Solar collectors
Collectors on A frame new building
Solar collectors
Collectors on A frame
Solar collectors
A frame with ballast prior to collector installation
Solar collectors
Collectors on a pitched roof
Solar collectors
Collectors on a pitched roof
Solar collectors
Collectors on facade
Solar collectors
System components

Storage vessel or heat exchanger

Must be sized accurately for collectors
CIBSE guidelines ask for a dedicated solar store of:
50-60ltr/m2 on evacuated tube systems
35-50ltr/m2 on flat plate systems
Manufacturers often ask for more
Usually installed next to the primary heat source
Heat exchangers used for specialised applications
   Solar store

of natural

                 Pre-heat store
Solar store Twin-Coil

 of natural
Controls: legionella

Legionella colonisation could occur within the solar
vessel, especially during spring/autumn when
temperatures within the vessel are likely to be lower.

Temperature control
Mechanical control
Solar Thermal store
Pipe work (sealed system)

Must be sized to suit the individual project

Should incorporate appropriate safety valves
and expansion vessels/protection vessels

Either specialist solar pipework systems or
Copper with high temperature press-fit fittings
Solar Control functions

                          Sollar Array

           S1 S2   R1
Solar Control functions solar display panel
Controls: safety heat-dump arrangement

          S1 S2 S4 R3 R1
Primary heat source

The primary heat source will satisfy the majority of the hot
water demand, therefore careful consideration should also
be given to this part of the design.

Efficiency of primary heat source is important
Consider condensing technology
Sizing of solar systems

Project Criteria
In order to provide an accurate sizing
the following information is required:

       •   Daily hot water demand
       •   Post code of the building
       •   Type of building
       •   Number of occupants per
       •   Roof space available and
           orientation/pitch of roof
Tsol sizing: calculation example
Tsol sizing: calculation example
Tsol sizing: calculation example
Tsol sizing: calculation example
Tsol sizing: calculation example
Tsol sizing: calculation example
System efficiency

To Recap
System efficiency is dependant upon:

Type of collectors used
Temperature of the DHW system
Installation of collectors
Solar fraction
Correct sizing of solar storage vessel
     System efficiency is typically around
System efficiency
System integration

The main methods of integration are:

Hot water systems
• Twin-coil calorifier
• Pre-heat store
Swimming pools
• Heat exchanger
Integration with pre-heat solar vessel
Integration with pre-heat solar vessel and heat
Solar system with HSK Thermal store and
boiler support

                                                                            EV           Boiler         EV         Boiler

                                                                                   TD                        TD

                                                                                                  NRV                       NRV

                                                                                   LSV            LSV        LSV            LSV

          Expansion Vessel                                                  A.S.


                                EV                  IV          IV          D.S.



                    Expansion Vessel

                                                                     2 PV


System integration: swimming pools
System maintenance

Collectors are generally self cleaning due to angle sited
Pressure within the system checked annually
Circulation pump checked annually
Visual inspection of collector array every 1-2 years
Check glycol mix condition annually
Thank you for listening

We would be pleased to
answer any questions?


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