Performance Comparison of a Latent Heat and Combined Thermal Energy Systems During Charging

The performances of three thermal energy storage (TES) systems are compared experimentally during charging cycles. The first storage system is a latent heat based storage system utilizing encapsulated adipic acid as phase change material (PCM), while the other two use a combination of encapsulated adipic acid and granite pebbles in a ratio 1:1. Placing the PCM capsules above the bed of rocks enhanced thermal stratification in the TES tank. Also, the energy and the exergy storage rates were enhanced by the arrangement. The worst performance is obtained by placing the PCM capsules at the bottom half of the tank. The superior thermal performance obtained by placing the cheaper sensible heat storage material (granite pebbles) beneath a bed of encapsulated PCM, will justify its use in order to reduce the cost of filling the packed bed entirely with encapsulated adipic acid.