Second law optimization of a sensible heat thermal energy storage system with a distributed storage element

This study explores the behavior of a flat-slab, sensible heat thermal energy storage system, the physical design and operation of which have been optimized to minimize the production of entropy by thermodynamic irreversibilities. Unlike many previous studies, the present work includes the entropy production by transient heat conduction within the storage element; that is, the analytical model is based on a distributed, as opposed to a lumped, storage element. The work is presented in two parts. The development of the analytical model required to compute the figure of merit, which is called the entropy generation number, in terms of the design and operational parameters of the system is presented in Part I. In Part II, the numerical solution of the analytical model is discussed and the results of an optimization study are presented and interpreted.

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Thermoeconomic design and analysis of a sensible-heat thermal energy storage system with Joulean heating of the storage element

Exergy An International Journal ◽

10.1016/s1164-0235(02)00074-2 ◽

2002 ◽

Vol 2 (4) ◽

pp. 237-247 ◽

Cited By ~ 4

Author(s):

Syed M. Zubair ◽

Meamer El-Nakla ◽

Shahzada Z. Shuja

Keyword(s):

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Storage System ◽

Energy Storage System ◽

Sensible Heat ◽

Storage Element ◽

Thermal Energy Storage System

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Second Law Optimization of a Sensible Heat Thermal Energy Storage System With a Distributed Storage Element—Part II: Presentation and Interpretation of Results

Journal of Energy Resources Technology ◽

10.1115/1.2905776 ◽

1991 ◽

Vol 113 (1) ◽

pp. 27-32 ◽

Cited By ~ 9

Author(s):

M. J. Taylor ◽

R. J. Krane ◽

J. R. Parsons

Keyword(s):

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Distributed Storage ◽

Storage System ◽

Energy Storage System ◽

Storage Element ◽

Thermodynamic Performance ◽

Thermal Energy Storage System ◽

Dwell Period

This study explores the behavior of a flat-slab, sensible heat thermal energy storage system, the physical design and operation of which have been optimized to minimize the production of entropy by thermodynamic irreversibilities. The analytical model is developed in Part I of this work. This part includes a description of the numerical model and the presentation and interpretation of the results of a system optimization study. The major results of this study show that: 1) any Second Law model of a thermal energy storage system must include a distributed storage element in order to make realistic estimates the thermodynamic performance of the system; 2) unconstrained optimization of the design of a thermal energy storage system tends to yield a system that is undesirably large, but by constraining the number of transfer units (NTU), it is possible to design systems of a realistic size without seriously degrading the thermodynamic performance; 3) counterflow systems operated without a dwell period are the most efficient type of system; and 4) the use of a dwell period with a counterflow system, or the operation of a system in parallel flow instead of counterflow, degrades the thermodynamic performance of the system and increases the required system size (NTU) in comparison to a counterflow system operated without a dwell period.

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