scholarly journals Analysis of models applied for modelling of adaptive control for thermal energy storage system. Part 2. Models of heat pump, borehole heat exchanger and phase change material tank

2018 ◽  
Vol 71 ◽  
pp. 73-87 ◽  
Author(s):  
Paweł Obstawski ◽  
Tomasz Bakoń ◽  
Jacek Gajkowski
Keyword(s):  
Adaptive Control ◽  
Energy Storage ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Storage System ◽  
Energy Storage System ◽  
Borehole Heat Exchanger ◽  
Thermal Energy Storage System ◽  
System Part ◽  
Change Material

The Optimum Design of Stratified Thermal Energy Storage Systems—Part II: Completion of the Analytical Model, Presentation and Interpretation of the Results

1992 ◽  
Vol 114 (3) ◽  
pp. 204-208 ◽  
Author(s):  
R. J. Krane ◽  
M. J. M. Krane
Keyword(s):  
Energy Storage ◽  
Heat Exchanger ◽  
Analytical Model ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Energy Storage System ◽  
Thermal Energy Storage System ◽  
Thermal Energy Storage Systems ◽  
Performance Gains

This investigation is presented in two parts. The basic analytical model is developed in Part I. Part II includes the completion of the analytical model and the results of an optimization study performed with this model. The results show that: 1) Significant performance gains, that is, reductions in the entropy generation number on the order of 10 percent, are possible by employing perfectly stratified thermal energy storage systems that are designed on the basis of the second law of thermodynamics. 2) These performance gains are mainly due to the complete elimination of the entropy generation due to heat transfer through finite temperature differences within the storage element. 3) In general, the optimum design of a perfectly stratified thermal energy storage system requires the use of a very large heat exchanger; however, it is possible to employ a much smaller than optimum heat exchanger without seriously degrading the superior performance of the system. 4) The operation of a stratified system is quite flexible because it has no optimum storage time. 5) The optimum values of the capacity rate ratios, (φR)opt and (φR)opt, for a perfectly stratified thermal energy storage system are in general not equal to unity; however, this finding is shown to be in concert with Bejan’s theory of “remanent” irreversibilities for a heat exchanger.

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