HIGH-PERFORMANCE PHASE-CHANGE THERMAL ENERGY STORAGE USING SPHERICAL CAPSULES

A theoretical and experimental investigation of the transient thermal characteristics of a phase-change thermal energy storage (TES) unit using spherical capsules is presented. A simulation program that considers rigorously transient aspects of both the surrounding heat transfer fluid and the phase change material (PCM) packed inside the spherical capsule is developed. The overall thermal response of this TES unit is described with variation of the capsule diameter, the flow rate, and the kind of PCMs, etc. The simulation results are then compared with experimental observations. Furthermore, a unique device employing a heat pump is presented to overcome the supercooling problem which has been one of the most serious problems (especially for inorganic hydrates) in the phase-change thermal energy storage.