An Investigation on Dehumidification and Heat Transfer Characteristics of a Minichannel Heat Exchanger for Heat Pump System of Electric Vehicles

Abstract

In this paper, a parallel flow minichannel heat exchanger was experimentally and theoretically studied under various operating conditions. A model of heat and mass transfer was developed and utilized to predict the dehumidification and heat transfer performance of the heat exchanger. The results show that under the operating condition of a low refrigerant mass flow rate, the dehumidification rate increases and then decreases with the increasing inlet airflow with a constant inlet air relative humidity. The lower the refrigerant mass flow rate, the higher the enthalpy humidity ratio when the inlet air humidity and inlet airflow are constant. As the refrigerant mass flow rate and the inlet air relative humidity remain unchanged, the enthalpy humidity ratio decreases as the inlet airflow increases. The results predicted by the proposed model agree well with the experimental results. The absolute errors of the predicted heat transfer rate and dehumidification rate concerning the experimental results are within ±4% and ±10%, respectively. The presented model can be employed for the evaluation of dehumidification and heat transfer performance of heat exchangers for the design and optimization of similar heat pump systems and their components.