Solar Water Heater is based on the principle of black body absorption. The black surface of the collector absorbs the heat from the sun rays and transfers it to the water passing through the pipes of the collector. Hot Water being lighter, rises to the insulated storage tank and an equal amount of cold water replaces this hot water. This cycle repeats as long as the sun shines, resulting in all the water getting heated for distribution through pipes to the required usage points.
In this case, water is cycled normally for heating through flat plate collector. It works on Thermos Siphon Technology. Normally, a Pressurized tank is used.
It normally uses Anti Freezing Liquid. Anti freezing liquid runs within collector and exchanges heat with water.
Direct circulation systems Pumps circulate household water through the collectors and into the home. They work well in climates where it rarely freezes.