Solar thermal systems collect free solar radiation, available throughout the year, via flat plate panels or evacuated tubes positioned on a building’s roof. This energy is used to heat water stored within a specially designed cylinder which then serves taps, showers, baths and any other appliances with a hot water feed. When necessary, a supplementary boiler will bring the water up to the required temperature.
In the summer this type of water heating system can provide all of a building’s hot water and up to 60% year round. Even on a cold, cloudy day the solar radiation will still be pre-heating the water in the cylinder, saving gas or electricity.
It is also worth mentioning that solar thermal collectors are included in the government’s non-domestic RHI (Renewable Heat Incentive) scheme – offering payments to the owner of the heat installation over a 20 year period. The current tariff for solar collectors (of less than 200kWth) is 8.9p/kWh.
Solar thermal water heating can help to save energy and fuel costs, so it is always worth considering this technology when a new water heating system is required, especially if there is a high-quality solar thermal hot water cylinder, and to ensure that it is correctly sized for the application and is well insulated.