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Two thermodynamic optima in the design of sensible heat units for energy storage

Publication ,  Journal Article
Bejan, A
Published in: Journal of Heat Transfer
January 1, 1978

The paper presents a treatment of sensible heat energy storage units as systems intended to store useful work. An analysis of the thermodynamic irreversibilities associated with storing energy from a hot gas source as sensible heat in huge liquid baths points out two important trade-offs: 1. There exists an optimum, well-defined quantity of hot gas to be used in order to maximize the useful work stored in the liquid bath. Using more than this optimum quantity in the hope of maximizing the amount of thermal energy stored as sensible heat leads to severe thermodynamics losses. 2. There exists an optimum relationship among the gas-liquid heat exchanger design parameters which minimizes the system irreversibility while maximizing its capability of storing useful work. This relationship provides a procedure for estimating the heat exchanger optimum number of transfer units (Ntu). Increasing the Ntu above the optimum in order to upgrade the heat exchanger effectiveness and the thermal energy storage capability leads to prohibitive losses due to fluid friction in the heat exchanger channels. The existence of the two optima demonstrates that designing sensible heat units for maximum thermal energy storage does not necessarily amount to thermodynamically optimizing such systems. © 1978 by ASME.

Duke Scholars

Published In

Journal of Heat Transfer

DOI

EISSN

1528-8943

ISSN

0022-1481

Publication Date

January 1, 1978

Volume

100

Issue

4

Start / End Page

708 / 712

Related Subject Headings

  • Mechanical Engineering & Transports
  • 4012 Fluid mechanics and thermal engineering
  • 0915 Interdisciplinary Engineering
  • 0913 Mechanical Engineering
  • 0904 Chemical Engineering
 

Citation

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Chicago
ICMJE
MLA
NLM
Bejan, A. (1978). Two thermodynamic optima in the design of sensible heat units for energy storage. Journal of Heat Transfer, 100(4), 708–712. https://doi.org/10.1115/1.3450882
Bejan, A. “Two thermodynamic optima in the design of sensible heat units for energy storage.” Journal of Heat Transfer 100, no. 4 (January 1, 1978): 708–12. https://doi.org/10.1115/1.3450882.
Bejan A. Two thermodynamic optima in the design of sensible heat units for energy storage. Journal of Heat Transfer. 1978 Jan 1;100(4):708–12.
Bejan, A. “Two thermodynamic optima in the design of sensible heat units for energy storage.” Journal of Heat Transfer, vol. 100, no. 4, Jan. 1978, pp. 708–12. Scopus, doi:10.1115/1.3450882.
Bejan A. Two thermodynamic optima in the design of sensible heat units for energy storage. Journal of Heat Transfer. 1978 Jan 1;100(4):708–712.

Published In

Journal of Heat Transfer

DOI

EISSN

1528-8943

ISSN

0022-1481

Publication Date

January 1, 1978

Volume

100

Issue

4

Start / End Page

708 / 712

Related Subject Headings

  • Mechanical Engineering & Transports
  • 4012 Fluid mechanics and thermal engineering
  • 0915 Interdisciplinary Engineering
  • 0913 Mechanical Engineering
  • 0904 Chemical Engineering