Designing of latent heat thermal energy storage systems using metal porous structures for storing solar energy

Abstract

The present work consists of increasing the thermal conductivity of the phase change materials (PCM) using metal foam structures for storing solar energy in form of thermal heat. In this regard, copper foam and copper/aluminium wire woven foam structures have been used to increase the thermal conductivity for a faster heat storage and extraction of heat from the PCM. The latent heat thermal energy storage (LHTES) systems with capacity of storing 300 KJ of thermal energy have been designed using the PCM and metal foam structures. Both the PCM–aluminium wire woven foam and PCM-copper foam composites took similar time for melting of PCM. The heat extraction of PCM–aluminium wire woven foam was high and found to be comparable to the PCM–copper foam composite system. The thermal efficiency of the various PCM-foam composite thermal energy storage tanks ranged from 60–70 % and 80–85 % on using water and air as the heat extraction media. The heat extraction continued for 3 – 4 hrs in case of cold water and 7 – 8 hrs in the case of cold air. The temperature of the cold air/water increased to 2 – 2.5 times of the original temperature after passing through the LHTES.