Investigation on the performance and environmental impact of a latent heat thermal energy storage system

Abstract

The present work provides an investigation into the performance of a thermal energy storage system. The energy storage device considered in the work is paraffin wax, which is a phase change material. Air serves as the heat transfer fluid in the present work. The performance of the system was evaluated in terms of overall energy and exergy losses, overall energy and exergy efficiencies, as well as heat exchanger effectiveness. The environmental impact of the system was also considered in term of sustainability index. The computational work was performed using the Engineering Equation Solver (EES) software. Parametric studies were also carried out to study the effects of various influential parameters like inlet temperature of heat transfer fluid during charging and discharging periods, air flow rate, and surrounding temperature. It was found that increasing the inlet temperature during charging and discharging, and air flow rate leads to increase in losses, thus reduces the efficiencies. However, effectiveness of the heat exchanger was observed to increase with a rise in the inlet fluid temperature during the charging period. Exergy loss and efficiency of the system reduce with an increase in the surrounding temperature. The surrounding temperature does not, however, affect the energy loss and overall energy efficiency of the system. Results further showed that the sustainability index of the system increases with any parameter that leads to an increase in the exergy efficiency.