What is the principle of thermal conversion of solar collectors?
the direct use of solar radiant energy, there are basically four ways, namely, solar energy - heat conversion, solar energy - electrical conversion, solar energy - chemical conversion and solar energy - biomass conversion, which solar Light-heat conversion is currently the most mature technology, the most cost-effective, and therefore the most widely used form
The basic principle is to collect solar radiation can use the greenhouse effect to heat objects and access to heat, such as plastic film, greenhouses, greenhouses and so on. At present, there are two kinds of solar energy collection devices: one is a flat type collector, such as solar water heaters, etc .; the other is a focus collector, such as reflective solar cookers, high temperature solar furnace.
According to heat transfer media classification: can be divided into liquid collector and air collector two categories, of which the liquid for the heat medium for most of the water as a medium, that constitutes a variety of solar water heaters; air for the heat transfer medium, It constitutes a variety of solar dryers. The core of the solar collector is the heat sink, which functions to absorb the radiant energy of the sun and transfer heat to the heat transfer medium. In the liquid as the medium, the heat-absorbing plate tube plate, wing tube, flat box, snake tube, etc., can be made of metal materials and non-metallic materials. The sunscreen surface of the heat-absorbing panel is coated with a black endothermic coating. The structure of the solar collectors for the heat transfer medium is often in the form of mesh, honeycomb and porous beds.
The most common solar collectors are non-concentrating flat type collectors. Its heat absorber body is basically flat shape, the area of heat absorption and the lighting area is approximately equal, its structure as shown in Figure (a) is the use of greenhouse effect of non-concentrating type collector. Enriched CO2 in the greenhouse can improve the greenhouse effect. Condenser type collector using the principle of focusing, that is, the use of light reflection and refraction principle, the use of reflectors or refractors to change the direction of the sun, the sun focused on the heat sink in the small area of the heat absorber, increase the unit area Of the radiation intensity, so that the collector to obtain a higher temperature.
solar collectors is a kind of solar energy can be converted into thermal energy equipment. As the solar energy is more dispersed, must try to put it together, so the collector is a key part of the use of solar energy devices. Because of the different use, the collector and its matching system type is divided into many kinds, the name is also different, such as cooking for the solar cooker, used to generate hot water solar water heater, dry items for the solar dryer, for Melting metal solar furnace, as well as solar houses, solar thermal power plants, solar desalination and so on.
