Investigation on the performance enhancement of electric vehicle thermal management system utilizing floating loop with finite heat exchanger size

Abstract

This study suggests an electric vehicle heat pump and thermal management system employing a floating loop. The floating loop manages the thermal state of power electronics and electric motors by utilizing the liquid refrigerant at the condenser outlet. This loop recovers the waste heat generated by power electronics and electric motors in winter and enhances the cooling performance in summer through the superior cooling performance of evaporative heat transfer. Configurations of heat pump and thermal management system are presented with operating schematic in summer and winter. To verify the performance of the suggested system, the heat pump and thermal management system model is established based on experimentally validated heat pump component models and electric device models. Heat exchangers are reallocated within a finite volume to investigate the effect of thermal load shift from the coolant to the refrigerant. The result shows that the heat pump system utilizing a floating loop with the largest refrigerant heat exchanger can save power consumptions in winter up to 27.7% and 5.8% in summer while maintaining the thermal state of electric devices within the appropriate range.