Thermal analysis of different heat pump systems for heating process of electric vehicles

Abstract

In this paper, three different 1D models of electric vehicle heating, ventilation, and air conditioning (HVAC) system integrated with the vehicle cabin model for heating process were developed. The numerical results were compared in terms of thermal performance to get the desired thermal conditions inside the vehicle cabin. The results of the hybrid heat pump 1D model including both HVAC components and an additional electrical heater showed better thermal performance than the others and it was proposed for the heating process of electric vehicles. At the end of the driving cycle, the average temperature inside the cabin was increased up to about 7 degrees C and 14 degrees C by using the conventional heat pump and innovative heat pump models, respectively, at -5 degrees C ambient temperature and the target temperature cannot be reached. However, under the same conditions, the vehicle cabin could be heated up to about 25 degrees C by using the hybrid heat pump model with a 1-kW electrical heater. In addition, the thermal performance of different heat pump systems can be improved by using electric vehicle thermal management system that allows performing transient simulations for the estimation of the dynamic behavior of system. This study also contributes to decrease of energy usage for HVAC processes that considerably affects the mileage of the vehicle and also life cycle of batteries. These 1D models can be used not only in thermal performance but also can be utilized for thermal comfort conditions of electric vehicles.