Experimental analysis of a fin-enhanced three-tube-shell cascaded latent heat storage system

The charging behavior of low-temperature cascaded latent heat storage (CLHS) has been a major research gap. In order to overcome the low thermal conductivity of organic phase change materials (PCMs), a fin-enhanced three-tube-shell latent heat storage unit is proposed in this paper. A full-scale experiment is carried out to study the temperature evolution and thermodynamic performance of CLHS unit of each stage and overall system. Through a sensitivity and correlation analysis, the influence of boundary conditions on the thermodynamic performance of this CLHS system is determined. The experimental results shows that the rate of temperature rise and energy charged of the first stage of the cascaded arrangement are significantly higher than those of the latter stages. It is recommended to use a PCM with higher specific heat values in the first stages, and use a PCM with a higher latent heat value in the later stages. The sensitivity analysis shows that the enhancement effect of the heat transfer fluid (HTF) inlet temperature on the energy and exergy rate is much stronger than that of its velocity. It is recommended that the HTF inlet temperature should be maximized as much as possible, and the HTF velocity should not be too high to obtain better thermal performance of the CLHS system.