Solar Water Heater

The solar water heater is a device which converses sunlight into renewable energy. It is used for water heating. The main part of the device is a solar thermal collector. The solar water heating systems consist of various technologies. Solar thermal heat is trapped using the ability of a reflective surface to transmit short wave radiation and reflect longwave radiation. The heat is produced when short wave radiation light hits a collector’s absorber. Fluid, usually water, in contact with the absorber collects the trapped heat to transfer it to storage. Two principles govern solar thermal collectors. The first one is that any hot object loses its heat back to the environment. The efficiency of a solar thermal collector is directly related to heat loss, mainly from convection and radiation. Thermal insulation is used to slow down the heat loss from a hot object to its environment. The second basic principle is – the heat loss is more rapid if the temperature difference between a hot object and its environment is larger, in this case between the temperature of the collector surface and the ambient temperature. The most basic approach to solar heating of water is to simply put a tank filled with water into the sun. The heat from the sun would heat the metal tank and the water inside. Solar water heating systems are designed to deliver hot water for most of the year. However, they are depended on sufficient solar heat gain. When sunshine or solar heat is not sufficient, a gas or electric booster is used to heat the water.