3.3.3.2 SPACE COOLING

Owing to the coincidence between cooling demand and maximum available solar irradiation, solar air conditioning appears to be a very promising technology, which might open a rapidly growing market. Solar cooling offers a solution to overheating during summer time and, in addition, reduces the summer midday peak electrical energy demand. Active solar cooling uses solar thermal energy or solar electricity to power a cooling appliance. There are various types of cooling technologies that utilize solar thermal energy.

Absorption cooling is the first and oldest form of air conditioning. An absorption air conditioner does not use an electric compressor to mechanically compress the refrigerant. Instead, the absorption cooler uses a heat source, such as natural gas or a large solar collector, to evaporate the already-pressurized refrigerant from an absorbent/refrigerant mixture, as shown in fig. 3.9. This takes place in a device called the vapour generator. Although absorption coolers require electricity for pumping, the amount is small compared to that consumed by a compressor in a conventional electric air conditioner. When used with solar energy systems, absorption coolers must be adapted to operate at the normal working temperatures for solar collectors: 82 - 120°C.

 

Source CRES-TRASOL CD-Rom
Figure 3.9 Air-conditioning with the aid of an active solar system