Experimental Investigation on Latent Thermal Energy Storages (LTESs) Based on Pure and Copper-Foam-Loaded PCMs

Abstract

In this work, a commercial paraffin PCM (RT35) characterized by a change range of the solid-liquid phase transition temperature Ts-l = 29–36◦ C and the low thermal conductivity λSL = 0.2 W/m K is experimentally tested by submitting it to thermal charging/discharging cycles. The paraffin is contained in a case with a rectangular base and heated from the top due to electrical resistance. The aim of this research is to show the benefits that a 95% porous copper metal foam (pore density PD = 20 PPI) can bring to a PCM-based thermal storage system by simply loading it, due to the consequent increase in the effective thermal conductivity of the medium (λLOAD = 7.03 W/m K). The experimental results highlight the positive effects of the copper foam presence, such as the heat conduction improvement throughout the system, and a significant reduction in time for the complete melting of the PCM. In addition, the experimental data highlight that in the copper-foam-loaded PCM the maximum temperature reached during the heating process is lower than 20 K with respect to the test with pure PCM, imposing the same heat flux on the top (P = 3.5 W/m2 ).