Numerical Analysis of an HVAC System Incorporated with Latent Heat Energy Storage System

Owing to India's climatic conditions, India’s energy outlook has predicted a three-fold increase in ownership and growth in energy consumed for cooling to 650 TWh by 2040. Further, due to airborne viruses like COVID-19, the health and air-conditioning societies modified guidelines and suggested incorporating air from the ambient to dilute the indoor air and reduce contaminant levels. However, mixing ambient air with recirculating air results in an additional cooling load in the heating, ventilation, and air-conditioning system (HVAC). The study aims to design a shell and tube heat exchanger to reduce the HVAC load by cooling the fresh air from ambient temperature and subsequently mixing it with the recirculated air. The fresh air at 315 K flows through the heat exchanger with calcium chloride hexahydrate as a phase change material (PCM). Further, two configurations of heat exchangers are examined. In one, air flows through the inner tube, and PCM is in the annulus, while in the second, the air flows in the annulus, and the PCM is in six radially equidistant tubes. The designed heat exchanger with PCM in annulus and PCM in tubes led to an average energy saving of 3 and 2.7%, respectively, for 3600 s of operation.