Solar Water Heater

solar water heater

A system in which the sun’s heat is gathered by a solar collector and used to increase the temperature of a heat-transfer fluid (such as water or a nonfreezing liquid) which flows through the pipes in the collector; the heat contained in this fluid then is conveyed and transferred to the water to be heated. Also see direct solar water heating system and indirect solar water heating system.

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Solar Water Heater 

a device using solar radiation to heat water to temperatures of up to 50°-60°C. Such water heaters may be employed in, for example, bathhouses and laundries.

Most solar water heaters are constructed without a solar-energy concentrator. In this design, the water heater consists of a thermally insulated box with a glass cover (seeSOLAR HEATER). Inside the box is a flat or tube boiler containing the water being heated. The sun’s rays pass through the glass and strike the blackened surface of the boiler, whereupon they heat the water. As the hot water is used, cold water is added to the boiler. A distinction is made between solar water heaters with gravity circulation and solar water heaters with forced circulation, where pumps are used. Usually the water heater is stationary; it faces south and is inclined at a certain angle to the horizon. Some water heaters are equipped with simple devices for changing the inclination according to the season. Solar water heaters are in lot production in many countries.