In FPC Solar Water Heaters ,the solar radiation is absorbed by Flat Plate Collectors which consist of an insulated outer metallic box covered on the top with glass sheet. Inside there are blackened metallic absorber (selectively coated) sheets with built in channels or riser tubes to carry water.
FPC based systems also performed well having anti freezing solution at subzero temperature. FPC are mainly used where the water level comes with heavy especially in commercial, hotels etc. and having more efficiency than ETC ( Evacuated tube collector ) based systems.