Solar Water Heater

A solar water heater is a device that converts sunlight into renewable energy for the purpose of heating water. The key component of the system is a solar thermal collector. Solar water heating systems employ various technologies, but they all function by capturing solar thermal heat. This is achieved by using a reflective surface that transmits shortwave radiation and reflects longwave radiation. Heat is generated when shortwave radiation strikes the collector's absorber, and a fluid, usually water, collects this heat and transfers it to a storage system. Two key principles govern the operation of solar thermal collectors. The first is that any hot object will lose heat to its environment. The efficiency of a solar thermal collector depends on minimizing heat loss, primarily from convection and radiation. To reduce this heat loss, thermal insulation is used. The second principle is that heat loss occurs more rapidly when there is a larger temperature difference between the hot object and its surroundings — in this case, the temperature difference between the collector surface and the ambient air. The simplest form of solar water heating involves placing a metal tank filled with water in the sun, allowing the heat from the sun to warm both the tank and the water inside. More advanced solar water heating systems are designed to provide hot water throughout most of the year. However, they rely on adequate solar heat gain. When there is insufficient sunlight, a gas or electric booster can be used to heat the water.