Solar water heating is the conversion of sunlight into heat for water heating using a solar thermal collector. A variety of configurations are available at varying cost to provide solutions in different climates and latitudes. Solar water heatings are widely used for residential and some industrial applications.
A sun-facing collector heats a working fluid that passes into a storage system for later use. Solar water heatings are active and passive. They use water only, or both water and a working fluid. They are heated directly or via light-concentrating mirrors.
Flat Plate Collectors (FPC) based 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. The absorber absorbs the solar radiation and transfers the heat to the flowing water. There are 60 BIS approved manufacturers of Solar Flat Plate Collectors.