Multi-objective optimization of a plate heat exchanger thermal energy storage with phase change material

Abstract

The plate heat exchanger thermal energy storage system is recognized as a highly efficient form of latent heat thermal energy storage. However, existing studies show that the efficiency and performance of these thermal energy storage systems are significantly affected by the design variables, indicating the need of optimization studies. This investigation thus conducts a response surface modeling analysis based on validated computational fluid dynamics simulations. Four design variables of the system are identified, and through response surface modeling the values of five responses such as average power and average effectiveness are predicted within the defined range of the design variables. A multi-objective optimization model then determines the optimal configuration of design variables for all responses, based on the response surface modeling and validated simulations. The results indicate that the optimal design has 21.4 % higher effectiveness than the normal design. The system also achieves maximum performance by employing 5 mm of the phase change material section thickness considering all the efficiency parameters. Moreover, charging the system over 10 °C above the PCM's melting temperature significantly decreases efficiency while providing minimal enhancement to power.