Thermodynamic performance of ice thermal energy storage systems

The thermodynamic performance of an encapsulated ice thermal energy storage (ITES) system for cooling capacity is assessed using exergy and energy ana lyses. A full cycle, with charging, storing, and discharging stages, is con sidered. The results demonstrate how exergy analysis provides a more realis tic and meaningful assessment than the move conventional energy analysis of the efficiency and performance of an ITES system. The overall energy and e xergy efficiencies are 99.5 and 50.9 percent, respectively. The average exe rgy efficiencies for the charging, discharging, and storing periods are 86, 60, and over 99 percent, respectively, while the average energy efficiency for each of these periods exceeds 99 percent. These results indicate that energy analysis leads to misleadingly optimistic statements of ITES efficie ncy. The results should prove useful to engineers and designers seeking to improve and optimize ITES systems. [S0195-0738(00)00904-3].