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].