Solar cooling: fresh air from the sun

The solar cooling is a recently developed technology based on systems that make it possible to exploit the heat of the solar thermal collectors to activate a thermodynamic cycle which has the purpose of cooling the rooms.

The heat generated through solar energy is in practice exploited for the summer air conditioning of buildings, which is very useful because the energy consumed in summer to produce fresh is almost equal to that for winter heating. The plants of solar cooling they can be of two types, classified according to the type of production that distinguishes them.

Of the first type are the plants of solar cooling closed cycle for the production of chilled water by means of 'chiller' thermal machines. In turn, these systems are distinguished between absorption systems, in which the heat transfer fluid is water combined with lithium bromide, lithium chloride or ammonia, and adsorption systems in which the heat transfer fluid is silica gel or water. and zeolite.

Of the second type are the plants of solar cooling for the production of air conditioning using a dehumidification and evaporative cooling process. These plants can be DECs (solid type drying rotor systems) or DECi (liquid type drying rotor systems).

Currently, according to data from the Energy Efficiency Report of the Politecnico di Milano, the only technology of solar cooling commercially available is the closed-cycle absorption plant which has a performance coefficient (C.O.P.) of 0.7 - 0.9 and a cost (euro / kWe) of 1,200 - 2,000. The closed-cycle adsorption plants are in a phase of first commercialization. The technology of the second type of plants, both DECs and DECi, is instead applied only to pilot projects.

Technology solar cooling for building cooling systems it is part of the solar thermal technologies, an area where solar radiation is usually used to produce heat, allowing savings on electricity and gas consumption.

Video: Solar Air Conditioning (October 2020).