Experimental performance of a small solar system for adsorption cooling in summer and heating in winter

Abstract

Solar energy is a kind of renewable energy with abundant resources and enormous reserves. Meanwhile, adsorption cooling technology can utilize natural refrigerants, thus also making this technology environmentally friendly. If solar energy can be effectively collected and utilized for heating in winter, then the environmental pollution caused by electricity and fossil energy consumption can be reduced. More importantly, considering engineering, the same solar device could provide cooling in the summer and heating in the winter. This study used parabolic trough and glass–metal vacuum heat collectors to conduct solar adsorption cooling and solar air heating experiments in summer and winter, respectively, to facilitate the complete and appropriate use of solar energy. Experimental results of solar adsorption cooling with silica gel as the adsorbent revealed that the coefficient of performance of the system reached 0.329. In addition, the influences of air flow rates and heat storage medium on the performance of the solar air heating system were investigated. Results revealed that the average and instantaneous efficiencies of the system considerably increased with the heat storage medium (i.e., water) filling in the annular cavity of the evacuated tube. The extended heating time also markedly increased by up to 170 min and was therefore of considerable practical value.