SECOND LAW ASSESSMENT FOR AN ANNULAR SENSIBLE HEAT THERMAL ENERGY STORAGE UNIT

Giuma Fellah; Fatma Ageel; Faraj El-Sagier

doi:10.66411/jer.v20i.274

Authors

Giuma Fellah Department of Mechanical and Industrial Engineering, Faculty of Engineering, University of Tripoli, Libya Author
Fatma Ageel Center of Industrial Researches Author
Faraj El-Sagier Department of Mechanical and Industrial Engineering, Faculty of Engineering, University of Tripoli, Libya Author

DOI:

https://doi.org/10.66411/jer.v20i.274

Keywords:

Thermal Storage Units, Entropy Generation, Irreversibility, Thermal Diffusivity

Abstract

This paper explores numerically the internal entropy generation and hence the internal irreversibility for an annular sensible heat thermal energy storage unit. Finite volume technique is adopted for the analysis with fully implicit numerical technique. A storage unit composed of two horizontal concentric cylinders with different diameters is considered for the analysis. The space between the two cylinders is filled with the storage material. Two different materials with different thermal diffusivities are considered for the analysis; those are cast iron and brick. The outside surface of the storage unit is insulated, while the inside surface exchanges heat by convection with air. The only mode of heat transfer inside the storage material is the heat transfer by conduction. The problem is a two-dimensional one. It is found that during the transient period, both the storage capacity and the internal entropy generation in cast iron are substantially higher than those in brick. However, as the steady state condition is approached with the increase in charging time, the discrepancies in the thermodynamic performance between the two storage materials are reduced.

References

[1] Cabeza L.F. Thermal Energy Storage. Comprehensive Renewable Energy, Solar Thermal Systems: Components and Applications, Components, 3, 2012, 211– 253. DOI: https://doi.org/10.1016/B978-0-08-087872-0.00307-3

[2] Thibodeau A. M. Numerical Model of The Transient Effects of a Heat of Fusion Reservoir Interacting with Two Phase Flow. Thesis of Doctor of Philosophy The Graduate School, University of Maine, December, 2002.

[3] Dincer I. The Role of Exergy in Energy Policy Making.Z Energy Policy, 30, 2002, 137-149 DOI: https://doi.org/10.1016/S0301-4215(01)00079-9

[4] Szargut J. International Progress in Second Law Analysis. Energy, 5, 1980, 709- 718. DOI: https://doi.org/10.1016/0360-5442(80)90090-0

[5] Szargut J. Morris D. R. and F. R. Steward. Exergy Analysis of Thermal, and Metallurgical Processes. Hemisphere Publishing Corporation, New York 1988.

[6] Bejan Α . General criterion for rating heat exchanger performance. Int. J. Heat Mass Transfer, 21, 1978, 655-658. DOI: https://doi.org/10.1016/0017-9310(78)90064-9

[7] Bejan Α . The concept of irreversibilityin heat exchanger design: counter flow heat exchangers for gas-to-gas. ASME, J. of Heat Transfer, 99, 1977, 374-380. DOI: https://doi.org/10.1115/1.3450705

[8] Saborio S. Α ., Ranasinghe J. and Reistad G. M. An extension to the irreversibility minimization analysis applied to heat exchangers. ASME, J. of Heat Transfer, 111, 1989, 29-36. DOI: https://doi.org/10.1115/1.3250654

[9] Bejan Α . Two thermodynamic optima in the design of sensible heat units for energy storage. ASME, J. of Heat Transfer, 100, 1978, 708-712. DOI: https://doi.org/10.1115/1.3450882

[10] Bejan Α . Entropy Generation Through Heat and Fluid Flow. John Wiley & Sons,New York 1982.

[11] Bejan Α . Advanced Engineering Thermodynamics. John Wiley & Sons, New York 1988.

[12] Domanski R. and Fellah G. Exergy as a tool for designing and operating thermal storage units. Biuletyn instytutu techniki cieplnej politechniki warszawskiej, 81, 1995, 24-45.

[13] Domanski R. and Fellah G. Exergy analysis for the evaluation of a thermal storage system employing pcms with different melting temperatures. Applying thermal engineering. Vol. 16, 11, 1996, 907-919. DOI: https://doi.org/10.1016/1359-4311(96)00003-8

[14] De Campos M. D. Analysis of Unsteady State Heat Transfer in the Hollow Cylinder Using the Finite Volume Method. Applied Mathematical Sciences, Vol. 6, 39, 2012, 1925– 931.