Thermodynamic Performance of Ice Thermal Energy Storage Systems

2000 ◽  
Vol 122 (4) ◽  
pp. 205-211 ◽  
Author(s):  
Marc A. Rosen ◽  
Ibrahim Dincer ◽  
Norman Pedinelli
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Analysis ◽  
Average Energy ◽  
Cooling Capacity ◽  
Energy And Exergy ◽  
Thermodynamic Performance ◽  
And Performance ◽  
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 analyses. A full cycle, with charging, storing, and discharging stages, is considered. The results demonstrate how exergy analysis provides a more realistic and meaningful assessment than the more conventional energy analysis of the efficiency and performance of an ITES system. The overall energy and exergy efficiencies are 99.5 and 50.9 percent, respectively. The average exergy 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 efficiency. The results should prove useful to engineers and designers seeking to improve and optimize ITES systems. [S0195-0738(00)00904-3]

Appropriate Thermodynamic Performance Measures for Closed Systems for Thermal Energy Storage

1992 ◽  
Vol 114 (2) ◽  
pp. 100-105 ◽  
Author(s):  
M. A. Rosen
Keyword(s):  
Energy Storage ◽  
Performance Measures ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Exergy Efficiency ◽  
Storage Process ◽  
Common Definition ◽  
Energy And Exergy ◽  
Thermodynamic Performance ◽  
Closed Systems

Several definitions of energy and exergy efficiency for closed systems for thermal energy storage (TES) are developed and discussed. A simple model is utilized in which heat quantities are transferred at specified temperatures to and from a TES. Efficiency definitions are considered for the overall storage process and for the three component periods which comprise a complete storage process (charging, storing, and discharging). It is found that (1) appropriate forms for both energy and exergy efficiency definitions depend on which quantities are considered to be products and inputs; (2) different efficiency definitions are appropriate in different applications; (3) comparisons of different TES systems can only yield logical results it they are based on a common definition, regardless of whether energy or exergy quantities are considered; and (4) exergy efficiencies are generally more meaningful and illuminating than energy efficiencies for evaluating and comparing TES systems. A realistic, but simplified, illustrative example is presented. The efficiency definitions should prove useful in the development of valid and generally accepted standards for the evaluation and comparison of different TES systems.

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