The investigation of the innovative hybrid heat pump system designed and prototyped for heating process of electric vehicles

Abstract

In this paper, the investigation of the innovative hybrid heat pump system (HHPS) included Positive Temperature Coefficient (PTC) heater commonly used in electric vehicles (EVs) was performed in different heating modes to reach the desired temperature in a target time. The developed HHPS was evaluated in different heating modes in order to reach the desired temperature considering the both target time and also vehicle driving range. It was shown that the driving range can be increased up to 15 % by using HHPS. As a result, a high-capacity PTC heater and HP should be work together at the beginning of the heating, and then the PTC capacity should be reduced gradually at lower ambient conditions. Another important result is that HHPS represent a promising solution for the new generation EVs that the target temperature was obtained lower than 300 s at lower ambient conditions. A numerical model was also developed to investigate the flow and the thermal characteristics of the EV cabin interior that enable to design more effective heating, ventilation and air-conditioning (HVAC) systems of EVs under different environmental conditions and the numerical results were in good agreement with the experimental data used in this study.