A Solar Water Heater (SWH) or Solar Thermal System is a device which provides hot water for bathing, washing, cleaning, etc. using solar energy. It is generally installed at the terrace or where sunlight is available and heats water during day time which is stored in an insulated storage tank for use when required including mornings.
It comprises of a or an array of solar collectors to collect solar energy and an insulated tank to store hot water. Both are connected to each other. During the day time, water in solar collectors gets heated which is pumped on thermosyphon principle to the storage tank. Hot water then stored in the tank can be used for various applications.
Two types of SWH are available; one based on flat plate collectors and the other based on evacuated tube collectors. Flat plate collector (FPC) based systems are of metallic type and have longer life as compared to Evacuated tube collector (ETC) based system because ETCs are made of glass which are of fragile in nature.