Plate type heat exchanger for thermal energy storage and load shifting using phase change material

•Thermal energy storage heat exchanger utilizing PCMs is designed and built.•Optimal plate-plate spacing is found to achieve maximum system performance.•Effectiveness greater than 80% at 4795 W power output was achieved.•The number of modular units is found for a targeted heat storage capacity. The study presents an experimental investigation of a thermal energy storage vessel for load-shifting purposes. The new heat storage vessel is a plate-type heat exchanger unit with water as the working fluid and a phase change material (PCM) as the energy storage medium. The thermal characteristics of the heat exchanger such as heat transfer coefficient, effectiveness, efficiency, water exit temperature, heat storage rate, total energy storage capacity and storage time were experimentally evaluated as a function of various inlet conditions. The compact parallel plate design showed an enhanced the performance compared to conventional storage systems with an effectiveness up to 83.1% even when a PCM of low thermal conductivity is used. The proposed phase change energy storage system not only can deliver substantial benefits as a thermal energy storage medium, but also provides cost savings in infrastructure, equipment, and maintenance/operations compared to conventional systems.