Centralized latent heat thermal energy storage system: Model development and validation

• Development of a mathematical model of a centralized LHTES for analyzing the thermal performance.
• Validation the numerical results of two and three-dimensional model with experimental data.
• Analysis of heat flow characteristics and phase distribution in a hybrid PCM closed system.
• Normalized analysis to assess the impact of temperature difference on the thermal performance.

Centralized latent heat thermal energy storage (LHTES) system offers potential benefits in energy efficiency, in load shifting, and in emergency heating/cooling load systems. A three-dimensional heat transfer model of a LHTES is developed to investigate the quasi-steady state and transient heat transfer of phase change materials (PCMs). The prediction of model is in good agreement with the experimental data. The effect of convective heat transfer on the melting rate of PCM is assessed. Through a parametric study, the effect of the temperature, PCM phase change temperature range, and the temperature difference of the incoming air and PCM melting temperature on thermal performance of PCM is undertaken. The temperature difference between the air as a heat transfer fluid (HTF) and the PCM melting point has a significant effect on the performances of a LHTES system. The thermal energy retrieved from the centralized LHTES system is the highest when the inlet air temperature is about 10 K higher than the PCM mean melting temperature. Correlations are obtained for the distribution of melting front and solid fraction as a function of time during charging and discharging of LHTES. These correlations can be used for further component optimization and design of cooling and heating systems.