Domestic solar hot water systems use the sun's energy to heat water in much the same way as water in a hose left lying on the lawn gets hot on a sunny day. To be effective they do not need direct sunlight but will receive energy from indirect sunlight (diffuse radiation), so will work even on a cloudy day. In the UK we get a lot of diffuse radiation and consequentially receive around 60% of the solar radiation found at the equator.
In a typical solar hot water system, water is heated as it circulates through flat, glazed panels or evacuated tubes (solar collectors), located on the roof of the house. This water is then circulated within a coil inside your hot water cylinder, so heating the water inside. On days when there is not enough solar energy, a conventional backup heater provides the necessary additional energy to heat your water to the desired temperature. This can be an electric immersion heater or more commonly a gas boiler.
Heating from sunlight
- (1) Solar Collectors
- (2) Storage Cylinder
- (3) Auxiliary Heating
- (4) Solar pump Station
- (5) Consumer supply
