Effects of void spaces in a phase change material based thermal energy storage system

A study is conducted to examine the effects of void spaces of air in phase change material based thermal energy storage (PCM-TES) system. A thermal simulation and analysis on a 2d axis symmetrical model is performed to simulate the effect of phase change, buoyancy driven convection and heat transfer. Two models are compared, one with a 20% air space and the other without. Both models are consistent in PCM volume. Results obtained from the simulation are validated by experimental results and showed good agreement. The model with the void space demonstrated characteristics which resembles a sensible heat storage system rather than the constant temperature characteristics of a latent heat storage system. The significant volume taken up by the void space could be reduced and replaced with more phase change material (PCM); which will increase the heat storage capacity of the system. Hence, understanding the effects of void spaces will be paramount in the development of future PCM-TES system designs.