Performance improvement of a dehumidifying heat pump using an additional waste heat source in electric vehicles with low occupancy

A DHP (dehumidifying heat pump) has been proposed to save energy consumption in electric vehicles during the dehumidifying and heating operation. Since the mean occupancy rate in a vehicle is less than two people, it is required to optimize the performance of the DHP at low occupancy for an effective operation. The objective of this study is to investigate the performance improvement of a DHP by using the additional waste heat source in electric vehicles with low occupancy. The experiments on the DHP were conducted by varying operating modes, according to various numbers of passengers. Even though the air source DHP in an AL (alternating) mode showed 7.6% lower heating capacity on average, compared to that in the DH (dehumidifying and heating) mode, the COP improvement of the air source DHP in the AL mode against the DH mode was approximately 31% for one passenger. In addition, the dual source DHP in the AL mode showed 15.8% higher heating capacity and 5.2% higher COP on average, compared to the air source DHP in the AL mode.