Solar water heating or solar hot water is water heated by the use of solar energy. Solar heating  systems are generally composed of solar thermal collectors, a water storage tank or another point of usage, interconnecting pipes and a fluid system to move the heat from the collector to the tank. This thermodynamic approach is distinct from semiconductor photovoltaic (PV) cells that generate electricity from light; solar water heating deals with the direct heating of liquids by the sun where noelectricity is directly generated. A solar water heating system may use electricity for pumping the fluid, and have a reservoir or tank for  heat storage and subsequent use. The water can be heated for a wide variety of uses, including home, business and institution uses. A solar water heating system can form part of a solar thermal cooling system, promoting efficient temperature control of buildings or parts thereof. During cool conditions, the same system can provide hot water.