SOLAR ASSISTED OPEN-CYCLE ABSORPTION COOLING: PERFORMANCE OF COLLECTOR/REGENERATORS

Abstract

In this study, a side-by-side test was performed on a glazed and an unglazed collector/regenerator operating under identical environmental conditions. This test procedure differed from previous experiments in that the inlet solution state was maintained constant during the period of testing. Also, for the glazed C/R, local solution film temperatures as well as entrance and exit air dry and wet bulb temperatures were measured. With the use of experimental data, empirical correlations were developed for heat and mass transfer coefficients in terms of Nusselt and Sherwood numbers. These correlations were used in the simulation study to identify important variables affecting the performance of each collector/regenerator. The performance of the glazed collector/regenerator was considerably affected by solution flow rate, solar irradiation, ambient temperature, solution temperature and concentration at the inlet, and glazing height. The evaporation rate for the unglazed collector/regenerator was strongly dependent upon ambient temperature, humidity, wind speed, and solution concentration at the inlet to the collector/regenerator. Generally, it was found that the unglazed C/R performed better than the glazed C/R for the conditions considered in this study. Contrary to previous research, this data showed an increase in evaporation rate as the gap height was decreased from 15 to 7 cm. The glazing, also helped to maintain cleaner absorbent solution and reduced waste due to rain. © 1997 by John Wiley & Sons, Ltd.