Heat Transfer Enhancement for Thermal Energy Storage Using Fin-Copper Foam within Phase Change Materials

Abstract

In the present work, the thermal energy storage unit using fin-copper foam embedded within paraffin phase change material has been designed and studied experimentally and analytically. The copper foam has a 97.19% porosity and the phase change material is 99% pure eicosane. The samples with copper fin thicknesses of 0.5 mm, 0.8 mm and 1.0 mm are processed and the calculation formula of their effective thermal conductivities is presented. The heat transfer performance of the samples are tested for different heat fluxes and compared with that of the single copper foam. The results indicate that the peak values of the maximum temperature differences inside the samples are reduced by Downloaded by [University of Sherbrooke] at 08:44 12 April 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2 73.2%-90.3% using fins. With the same fin interval, the maximum temperature difference increase with the augmentation of the heat flux and the reduction of the fin thickness. It was found that the effective thermal conductivity of the copper foam/paraffin (CFP) composite with 1.0 mm fin is 11.4 W/(m·K), which is 3.7 times as that of the CFP composite and 42.2 times as that of the pure paraffin. Based on the results, a new Nusselt-Rayleigh number correlation for the melting of the CFP composite with fins is proposed.