Solar Water Heater
Solar water heating (SWH) is the conversion of sunlight into heat for water heating using a solar thermal collector. A variety of configurations is available at varying cost to provide solutions in different climates and latitudes. SWHs 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. SWH are active (pumped) and passive (convection-driven). They use water only, or both water and a working fluid. They are heated directly or via light- concentrating mirrors. They operate independently or as hybrids with electric or gas heaters.  In large-scale installations, mirrors may concentrate sunlight into a smaller collector.