An experimental investigation of dehumidifying and reheating performances of a dual-evaporator heat pump system in electrified vehicles

Abstract

Climate control system in electrified vehicle is quite different from traditional internal combustion engine vehicle, as it cannot use the wasted coolant heat from engine to keep warm of the cabin. For the dehumidifying and reheating air in the electrified vehicle cabin, the use of a dual-evaporator heat pump system could improve the total energy utilization efficiency of the climate control system. In this study, an experimental dual-evaporator heat pump system was set up to investigate dehumidifying and reheating efficiency of a cabin in electrified vehicle. Two dehumidifying modes were chosen in this experiment. One was single-evaporator mode with indoor evaporator only, and the other was dual-evaporator mode with both indoor and outdoor evaporators. The dual-evaporator dehumidifying mode shows higher heat capacity, coefficient of performance, and outlet air temperature, while it has quite lower moisture extraction rate and specific moisture extraction rate compared to the single-evaporator dehumidifying mode. Therefore, a hybrid dehumidifying and reheating method was suggested as a possible option for realization of energy conservation without sacrifice of thermal comfort for passengers.