Analysis of a flat-plate collector serving as a generator in an intermittent solar refrigeration system

The refrigerating effect that can be realized from an intermittent solar absorption refrigerator depends largely on the amount of refrigerant distilled during the generation process. Although the amount of refrigerant generated and the performance of the system can be predicted from thermodynamic analysis, information is not obtained on variations with time of solution temperature, plate temperature and mass of refrigerant distilled during the generation process, for a given pattern of incident solar radiation. A method for heat-transfer analysis of the collector to obtain the time variation of the specified parameters is discussed in this paper. The chosen refrigerant and absorbent for analysis and comparison with experimental data are ammonia and water, respectively. An equivalent electric circuit, based on lumped thermal resistances and capacitances, is used for analysis. Agreement between predicted and experimentally-observed quantities is good. © 1989.