Transcript Solar Water Heating Systems

SOLAR for HOT WATER and
HEATING
Here Comes the Sun - London Solar: heat with care
WHAT SOLAR HEATING HAS TO OFFER…
• A MATURE & WELL ESTABLISHED TECHNOLOGY
• VERY WIDESPREAD APPLICATION
• SOLAR HEATING is a VERY LOW CO2 EMITTING TECHNOLOGY
• EFFICIENT CONVERSION of LIGHT to HEAT
• VERY GOOD for HOT WATER and CAN WORK VERY WELL for HEAT
• COMBINES WELL with CONVENTIONAL HEATING SYSTEMS & OTHER
RENEWABLE TECHNOLOGIES
HERE COMES THE SUN
SOLAR for HOT WATER and HEATING:
• A MATURE & WELL ESTABLISHED TECHNOLOGY
solar water heating is ‘OLD TECH’…
In California, USA “CLIMAX” Solar Water Heaters were sold & installed from
1890’s.
Clear standards for design & manufacturing:
EN 12975 test standards for solar collectors
EN 12976 for ‘intrinsically secure’ design & installation
The UK market is now well regulated through the
Microgeneration Certification Scheme (MCS)
Product & Installation standards for a range of renewable technologies
The UK has the world’s longest established trade body for solar
technologies… The Solar Trade Association
HERE COMES THE SUN
SOLAR for HOT WATER and HEATING:
• A MATURE & WELL ESTABLISHED TECHNOLOGY
Installation standards are much higher in Britain now.
A STANDARD SOLAR HEATING SYSTEM …
… is INDIRECT, separate from the water we use
… has GLAZED, INSULATED solar collectors
… has mains-powered circulation pump
… uses SOLAR-SPECIFIC components: pumps, valves, insulation etc
HERE COMES THE SUN
SOLAR for HOT WATER and HEATING:
• VERY WIDESPREAD APPLICATION
latest global statistics (source: IEA SHC):
over 400 million sq.m. solar collector area installed around the world
(40,000 hectares = around 56,000 football pitches of collector area)
Approximately 300 GigaWatts = 300,000 MegaWatts capacity
Around TWO THIRDS of total global capacity is in one country...
TOTAL installed solar collector area in UK in 2005 was around 100,000 sq.m.
ANNUAL installed area around 100,000 sq.m. in UK now.
HERE COMES THE SUN
SOLAR for HOT WATER and HEATING:
• SOLAR HEATING is a VERY LOW CO2 EMITTING TECHNOLOGY
assuming it has been appropriately chosen, well designed & installed…
a solar water heating system will:
consume around 50kWh of energy a year to run
provide between 1000 and 1800 kWh useful energy a year
offset a further roughly 25% of efficiency loss for a (modern, efficient) gas boiler
TOTAL ENERGY OFFSET perhaps around 1500 to 2000 kWh a year
NO NEED TO WAIT FOR THE ELECTRICITY GRID TO GO GREEN
OR RELY ON OTHER PEOPLE REPLANTING BIOMASS
HERE COMES THE SUN
SOLAR for HOT WATER and HEATING:
• EFFICIENT CONVERSION of LIGHT to HEAT
MAXIMUM CONVERSION EFFICIENCY OF A SOLAR COLLECTOR
over 80%... REALISTIC OVERALL SYSTEM EFFICIENCY around 50%
compares well to the Internal Combustion engine: around 15 to 20%
and very well to PLANT GROWTH, around 1 – 2%
This makes SOLAR THERMAL COLLECTORS VERY SPACE-EFFICIENT
this helps solar heating systems do a lot with a small area:
For solar water heating a collector area of around 4 sq.m. is common
For space heating & combi’ systems, a typical collector area is between 6 and 12
sq.m.
HERE COMES THE SUN
SOLAR for HOT WATER and HEATING:
• VERY GOOD for HOT WATER and CAN WORK VERY WELL for HEAT
SOLAR CAN WORK VERY WELL FOR HEATING BUILDINGS
There are more constraints and complications than for water heating:
NEEDS: a well-insulated building that can be heated at lower temperatures (just as for heat pumps to work
effectively)
a larger collector area and more storage by some means.
“COMBI-SYSTEMS” that do heating and hot water are common across Europe, now most of solar collector
area installed in Germany, Austria, much of France
STORAGE & DISTRIBUITION OPTIONS ARE MULTIPLE & MORE COMPLEX
APPROPRIATE DESIGN IS VERY IMPORTANT
HERE COMES THE SUN
SOLAR for HOT WATER and HEATING:
• VERY GOOD for HOT WATER and CAN WORK VERY WELL for HEAT
SKYRAD – UK patented design, installed in London & Birmingham, solar
thermal & External Wall Insulation for ‘hard to heat’ solid wall
buildings - costs around £16,000. Gas savings around 85%, data
from installed systems.
COMBI-SYSTEMS with THERMAL STORES
a range of options available, highly dependent on buildings &
occupants’ heat needs
HERE COMES THE SUN
SOLAR for HOT WATER and HEATING:
• SOLAR THERMAL is useful for HOT WATER AND HEAT
TYPICAL INSTALLED COSTS – materials & labour
SOLAR HOT WATER: system (without storage)
high-efficiency hot water store:
SOLAR SPACE HEATING varies more widely:
£2700 to £3600
£800 to £1800
£8500 to £18000
HEAT & ENERGY USE
Over 80% of the energy we use in our homes is for HEAT
• Average domestic hot water demand around
2,500kWh, though varies widely
• Typical hot water storage losses between 500
and 800kWh per year
• Poorly insulated pipework and cylinders can
loose up to 2,910kWh per year
• Well-installed solar water heating system can
save 1,500kWh of hot water energy
Installation Step
Energy Bill Saving per
year
More efficient boiler
Possibly very large
New cylinder with
75mm insulation or
added jacket
£45
Pipework insulation
£15
Solar Thermal
£55 replacing gas
£88 replacing electric
How does it work?
S1
Collector temperature
S2
Upper hot water store
temperature
S3
lower hot water store
temperature
S1
S2
When S1 is hotter than S3, the
controller switches the pump
on, which circulates the heat
transfer fluid. This warms the
hot water cylinder.
S3
Renewable Heat Incentive
19.2p/kWh for hot water provided by solar water heating for 7 years.
The total amount over 7 years ranges between £1,200 and £3,200.
Amount of hot water depends on:
• Occupancy
• Hot Water Usage
• Boiler Efficiency
Green Deal assessment required for eligibility
• Loft must be lagged to at least 250mm
• Cavity walls must be filled.
Legacy customers since 15th July 2009 included.