Theoretical Analysis for Heat Transfer Optimization in Subcritical Electrothermal Energy Storage Systems

Abstract

Electrothermal energy storage (ETES) provides bulk electricity storage based on heat pump and heat engine technologies. A subcritical ETES is described in this paper. Based on the extremum principle of entransy dissipation, a geometry model is developed for heat transfer optimization for subcritical ETES. The exergy during the heat transfer process is deduced in terms of entropy production. The geometry model is validated by the extremum principle of entropy production. The theoretical analysis results show that the extremum principle of entransy dissipation is an effective criterion for the optimization, and the optimum heat transfer for different cases with the same mass flux or pressure has been discussed. The optimum heat transfer can be achieved by adjusting the mass flux and pressure of the working fluid. It also reveals that with the increase of mass flux, there is a minimum exergy in the range under consideration, and the exergy decreases with the increase of the pressure.

Exergetic Analysis and Exergy Loss Reduction in the Milk Pasteurization for Italian Cheese Production

“…To achieve the aim of energy efficiency, the exergetic balance is a modern and powerful tool, introduced in the middle of the previous century [12,13], based on the linear combination of the other two balances: the energy balance (First Law of Thermodynamics) and the entropy balance (Second Law of Thermodynamics) [14]. With exergetic analysis, it is easier to understand the dissipative phenomena accompanying the use of energy [15][16][17][18][19][20][21][22].…”