Latent heat thermal energy storage solution for CSPs: Integration of PCM heat exchangers

Abstract

In the last few decades, alternate and renewable energy harvesting techniques, such as Concentrated Solar Power (CSP), have attracted attention as a unique source of electricity. However, the intermittent nature of solar energy results in discontinuous electricity generation. Thus, the integration of a Latent Heat based Thermal Energy Storage (LHTES) system will help in managing this issue. This numerical study explores the heat storage and discharge abilities of Phase Change Material (PCM) to design an efficient energy storage system. In this study, a 2D novel geometrical model is introduced to enhance the performance of PCM based heat exchanger module. Finite Volume Method (FVM) has been used to simulate the complex phase change problem via ANSYS Fluent solver. The double pipe heat exchanger with concentric cylinders is considered as the base case and multiple design modifications with augmented heat transfer areas have been provided. Comparison of different configurations by varying geometrical parameters with base case is carried out. The improvement in the rate of phase change is observed as the base case tube is replaced by semi-circular tubes in the system. The reduction in sensible heat storage is large during initial stages of charging, a reduction is observed as 46%, 43.5% and 48.9% respectively for all three cases. The time taken to achieve a maximum storage and discharge effectiveness of 82%, 85% respectively is less for novel configurations as compared to base case. It is observed that both novel configurations can be useful to store and release faster which can be used in meeting the energy demand on time.