In recent years, EVs have attracted considerable attention as eco-friendly vehicles. Owing to a significant decrease in fuel economy during the winter season, heat pump technology is currently being applied for EVs in lieu of the standard electric heater option. However, heat pumps need to defrost periodically due to the accumulation of frost on the heat exchanger’s outer surface, which compromises the security of the heat source as well as system efficiency. The proposed PCM module has a double-tube structure chargeable either from the heat pump through waste heat, or from the battery through the liquid line, during normal operation. As opposed to the electric heater, which reduces fuel economy during heat pump defrosting, the PCM module is proposed for cabin heating by air. The effectiveness of the unique inner fins located in the PCM is proven by CFD analysis, and the solidification thermal behavior is measured for a test section using C20H42 (Icosane). A one-dimensional thermal model with an accuracy of ± 1 °C is proposed to estimate the air outlet temperature and heat capacity over time during heat discharging, as a basis for future investigation of fuel economy improvement using the PCM module at vehicle level.
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