Thermodynamics of phase-change energy storage: The effects of liquid superheating during melting, and irreversibility during solidification

This paper considers the question of whether the optimum phase-change temperature for maximum exergy storage is universally equal to the geometric mean of the heat source and environment temperature, Tm= (T∞, Te)^1/2. The study consists of three parts. The first deals with the conduction-melting process, and shows that the optimum melting temperature is generally greater than the geometric mean of the source and environment temperatures. The second part covers the conduction-solidification process, and concludes that the irreversibility of solidification decreases monotonically as the phase-change temperature increases. The third part treats the complete cycle of melting (storage) followed by solidification (retrieval), and demonstrates that the optimum phase-change temperature is greater than the optimum temperature of the melting process alone. © 1991 by ASME.

Duke Scholars

Author Adrian Bejan Thomas Lord Department of Mechanical Engineering and Materia ...