Energy conversion efficiencies between panel types are generally small. Durability and long lasting-low maintenance are the key issues under consideration (EN12975 1&2).
Utilisation factor‘UF’ is the percentage of available solar energy actually consumed regarding DSWHS efficiency and daily- seasonal hot water demand patterns. According to numerous consumer profiles and solar radiation combinations assessed ‘UF’ basically varies from 25 to 40% [f].
Costs- payback time In the UK systems vary from £2,000 to £6,000 [g],[f] depending on:
- size of dwelling
- occupancy
- scaffolding
- grants
- cylinder type
- solar system type
Grants currently in the UK are £400 and from 2011 there shall be a yearly grant introduced.Average life-span of installations after 1996 are up to 20 [f]. Companies provide 25 year cylinder guarantees and 10 year guarantees on collectors mentioning life spans of over 30 years.
Sustainability-Environmental impact It is possible to save roughly half a tonne carbon dioxide emissions. Relevant European standards:
- EN 806: General installation specifications.
- EN 1717: Protection against pollution of potable water -device requirements concerning pollution by backflow.
- EN 60335: Safety specifications regarding household and relative electrical appliances.
- EN 94002
Solar space heating:Alternative use of Solar thermal systems is space heating usually through connecting collectors to under floor systems due to the lower maximum temperatures required in this case (45ºC-50ºC). Especially when installed in concrete can prove to be an ideal heat sink and emitter. Solar supported under floor heating systems require a cylinder size of more than 1000 lt. A considerable amount of solar panel area is required with an optimum inclination angle 60º-90º as they are focused in absorbing mainly winter solar radiation. |