Solar ARSs

Solar energy is renewable and ozone-friendly source of energy. Solar cooling is the most attractive subject for many engineers and scientists working on solar energy. The majority of research and development was carried out using an absorption cooling system. This system usually is the preferred alternative as it uses thermal energy collected from the sun without having to convert this energy into mechanical energy, as required vapor-compression system. In addition, absorption cooling system uses heat energy at lower temperatures (i.e. in the range of 80-110VC)than the vapor-compression system.

Research and development on solar ARSs, using different combinations of refrigerants and absorbents as working liquids have been done. These ARSs to have a good potential, where solar energy is available as low-grade heat energy at a temperature level of 100VC and above.

The principle of operation of solar powered absorption cooling system is the same as absorption cooling system shown in Fig. 3.57, except for the heat source to the generator. On Fig. 3.57, we presented the absorption of solar cooling systems using R-22 (refrigerant)-DMETEG absorbent combination as a working fluid (Dincer et al., 1996). Its operation can be summarized as follows. In the absorber, DMETEG absorbs R22 at low pressure and shock absorber temperature supplied on the reverse of the water and, consequently, there is a strong solution of (2). This strong solution of the absorber decision on a pump, which increases its pressure and provides a solution to the generator through a heat exchanger (3-6).

generator, which is heated by solar hot water system, increases the temperature of the strong solution, causing R-22 separate from it. The rest of the weak solution flows through the expansion valve, the heat exchanger and strangled in absorber for further cooling, as he picks up a new charge R22 pairs, becoming a strong solution of (6-2) again. Hot R-22 pairs from the generator passes into the condenser, and is available in a liquid phase (8-9). The liquid R-22 enters its second heat exchanger and loses heat to the cool R-22 pairs. Pressure of a liquid, R-22, drops dramatically in the throttle before it enters the evaporator. The loop ends when the required cooling load is achieved in the evaporator (10РІР‚12). Cool R-22 pairs obtained from the evaporator is in the absorber in a weak solution comes absorber, continuously. R-22 pairs is absorbed here (12РІР‚1). This absorption activity reduces the pressure in the absorber, causing the steam to be subtracted from the evaporator. When a couple goes to a liquid solution, it releases both its latent heat and thermal dilution. This energy release should be continuously scatters cooling water.

Solar-worked ARSs reached limited commercial viability due to their high cost/benefit ratios. The main factor responsible for the disadvantage is the low COP associated with these systems, which, as a rule, are conventional thermodynamic cycles with a total working fluid. It is important to explore the use of alternative fluids, working in new thermodynamic cycles. In addition, the development of more effective, less expensive solar collectors will be a continuing need for solar energy to reach their full potential.