Performance comparative study of a solar-powered adsorption refrigerator with a CPC collector/adsorbent bed

Solar adsorption refrigeration has many advantages. However, solar radiation has a relatively low energy density and requires much time to heat an adsorbent bed. In addition, the coefficient of performance (COP) of an adsorption refrigeration system is relatively low. In this paper, a new solar adsorption refrigeration prototype, which uses a compound parabolic concentrator (CPC) adsorbent bed with activated carbon-methanol as the working pair, was proposed and built to shorten the cycle time and improve performance. Laboratory experiments were conducted to evaluate and compare its performance and characteristics to those of a conventional solar adsorption refrigeration system. The experimental results show that the speed of the temperature increase of the adsorbent bed was boosted by employing CPC collectors. Compared with a conventional refrigeration system, the desorption period of the new system was reduced by one-third over one cycle. The desorption rate of the adsorption refrigeration cycle was notably improved. By using the CPC collector in a solar adsorption refrigeration system, the COP increased by 27%. The experimental results also show that applying solar concentrating technology in adsorption refrigeration is a promising approach for improving solar adsorption refrigeration performance and achieving a fast and continuous refrigeration cycle.