Optimal phase change temperature for BCHP system with PCM-TES based on energy storage effectiveness

Abstract

Integrating thermal energy storage (TES) equipment with building cooling heating and power (BCHP) system can improve system thermal performance. In this paper, a simplified model of TES-BCHP system is presented with phase change material (PCM). Moreover, a new index, energy storage effectiveness, is proposed and its relationship with primary energy consumption is established. To maximize energy storage effectiveness, the optimal phase change temperature of PCM-TES-BCHP system is obtained. The results show that the theoretically optimal phase change temperature is just the geometrical average value of ambient temperature and exhaust gas temperature from gas turbine for ideal PCM-TES equipment with infinite NTU. It also indicates that both energy storage effectiveness and optimal phase change temperature increase with increasing NTU. So improving the thermal performance of PCM-TES device is favorable for increasing energy efficiency and saving primary energy consumption. This work can provide guidance for the design of PCM-TES-BCHP systems.