Solar Collectors

Two technologies are involved in the utilization of solar energy. They are solar thermal and solar photovoltaic. Solar collectors are required to collect solar power. Non-concentrating type solar collectors absorb the radiation on reaching the surface of the collector. In a concentrating type solar collector, before absorption, concentration of radiation per unit area is increased by proper optical mechanism. Concentrating type solar collectors can be subdivided into two: line focus and point focus. Three important parameters of solar collector are collector efficiency, concentration ratio and temperature range. Collector efficiency is defined as the ratio of the energy actually absorbed and transferred to the heat-transport fluid by the collector to the energy incident on the collector. Concentration ratio is the ratio of the aperture area of the system to the area of the receiver. The range of temperature to which the heat transport fluid is heated by the collector is known as temperature range.