Performance investigation of latent heat energy storage in series and parallel arrangement: A numerical study

Abstract

Latent heat storage is a prolific technology to ensure a continuous heat supply. Charging and discharging plays a vital role in deciding the overall performance of the storage system. In the case of multiple units of latent heat storage, the storage performance depends on the type of heat exchanger connection (series/parallel), heat-carrying fluid passage, and flow parameters. The rectangular shell and tube heat exchanger are selected to investigate the effect of connection and flow parameters during the charging and discharging. The series and parallel connection of rectangular shell and tube heat exchanger filled with phase change material RT35 is simulated for charging and discharging in ANSYS FLUENT. The heat-carrying fluid's temperature and flow rate are varied to report the effect of flow parameters. The inlet temperature of heat-carrying fluid water is kept at 80 °C and 60 °C, while the flow rate ranges from 0.6 LPM to 1 LPM. The results indicate that the series arrangement is better than the parallel arrangement in all flow conditions in both charging and discharging cycles. For series and parallel connection, when the flow rate increases from 0.6 LPM to 1 LPM, melting time reduces up to 24 % and solidification time up to 30 %. Moreover, charging gets affected by the inlet temperature of heat transfer fluid, a 42 % increase in melting time is observed when inlet temperature is reduced from 80 °C to 60 °C.