An Experimental Study on Heating Performance Characteristics Using a Dual Latent Heat Pump System of an Electric Vehicle

This study proposes a dual latent heat pump system to improve heating efficiency and reduce winter power consumption in electric vehicles. The proposed system enables two-stage latent evaporation by adding an external heat exchanger to a conventional heat pump. Experiments conducted in a low-temperature chamber under conditions ranging from -5°C to 15°C revealed that the refrigerant mass flow rate decreased by 2-3% compared to that in a conventional system; however, both heat absorption and superheat increased significantly. Consequently, compressor work increased by 1-16%, and condenser heat release improved by 1-4%. Although the COP H decreasedby2-13%, the indoor heating temperature increased by 7-11% under ambient temperatures of 5°C or below. These performance improvements indicate a potential reduction in PTC heater operation time, contributing to energy savings.