ScholarWorks@중앙대학교

초록

Electric vehicle (EV) heat pump systems exhibit strong sensitivity to refrigerant charge because pressure levels, phase distribution, and control targets differ fundamentally between cooling and heating operation. This study experimentally investigates whether a simplified refrigerant storage architecture using a single storage device can maintain robust dual-mode performance in an R1234yf EV heat pump system. A baseline system employing both a receiver and an accumulator was compared with two configurations relying on the single storage device over wide charge sweeps in both modes. Beyond a component-level comparison, this study provides a dual-mode evaluation that links the storage architectures to the control strategy, practical charge window, governing mechanism, and limiting factor of each configuration. In cooling mode, receiver-bypass configuration achieved the optimum performance with capacity of 4.82 kW and COP of 1.49, while accumulator-bypass configuration performed comparably to the baseline. Whereas, in heating mode, receiver-bypass configuration maintained baseline-level performance with capacity of 2.51 kW and COP of 3.28 over wide range, while accumulator-bypass configuration showed the peak heating capacity of 3.50 kW and rapid COP deterioration in high charged region. These results demonstrate that storage architecture for EV heat pumps should be selected based on dual-mode charge window robustness rather than peak COP or capacity alone, as gains in maximum performance are achieved at the expense of severely reduced operability.

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