A first and second law analysis of phase change heat exchangers for energy storage

摘要

The external heat trnafer and pressure drop irreversibilities on account of the interaction between the heat transfer fluid and the storage element are characterized andthe latent heat storage system performance is studied in terms of first and second law efficencies. A parametric study is conducted to assess the effect of the sensible heating prior to melting and subcooling of phase change material after solidification, in tandem with the effect of heat exchanger size. The effect of the phase change temperatue on exergy destruction within the phase change material is studied as a function of the charge fluid inlet temperature as well as that of the heat exchanger size. A higher degree of sensible heating prior to melting , a lower level of subcooling after solidification and preheating of discharge fluid are found to lead to a better performance.