Design and Optimization of Air to PCM Heat Exchanger Using CFD

Energy storage may shift and reduce peak power demand throughout the year. The ventilation system can be improved by incorporating phase change materials in heat exchangers as thermal energy storage. Optimizing and developing the air to a PCM heat exchanger is crucial. Using ANSYS (FLUENT 19.2), the numerical 2D model is used to optimize the heat transfer performance between airflow and PCM slabs. As latent heat thermal energy storage, nine rectangular slabs filled with PCM-RT25 were proposed. The PCM panels are 10 mm thick, and there is a 20-mm air channel between them. The PCM is encapsulated in 3-mm steel, and the shell is insulated with 10-mm wood. The length of the heat exchanger is 1 m, and its width is 0.6 m. The CFD model has been used to investigate the liquid fraction in PCM panels, as well as outlet air temperature and pressure drop through air channels. The findings revealed that air channel height, PCM panel height, melting temperature of PCM, and the heat exchanger's length-to-width ratio significantly impact melting and solidification rate through charging and discharging PCM. The proposed APHX takes 4 and 3.25 h to melt and solidify, respectively. The result of using RT25 + RT21 in succession is the same as using RT21 for melting, with a 1-h reduction in solidification time.