Numerical Analysis of Thermal Energy Storage Performance

Abstract

In this paper, a numerical analysis of a latent heat thermal energy storage (TES) system that utilizes a phase change material (PCM) is presented. A two-dimensional geometric model of the storage unit was created within COMSOL Multiphysics, and a transient heat transfer analysis was performed using the finite element method. The model was utilized to determine the temperature distribution within the TES domain and the thermal response of the storage material during the charging cycle. The data indicated that as time progressed, the temperatures within the TES increased steadily, which is indicative of continuous heat transfer and good thermal storage capabilities. At 15 hours after the beginning of the charging cycle, while the temperatures within the storage area are low and not uniform, after 20 to 25 hours, temperatures are seen to be much higher and much more uniform across the storage domain. The temperatures were uniformly distributed around 60 °C, which is indicative of a phase change and the absorption of latent heat. At 30 hours the TES is charged, with the maximum temperature for the TES approaching 348 K. The temperature histories at 0.06 m and 0.09 m from the base of the TES confirm very stable charging characteristics with very little variation between the two locations. The results show that PCM based thermal energy systems are viable for effective thermal energy storage purposes.