Design of a Heat Pump Cycle for PCA systems and Analysis of CO₂ Emission for Aircraft Heating on the Ground

This study proposes a heat pump-based Pre-Conditioned Air (PCA) system as an alternative to the Auxiliary Power Unit (APU), which emits a significant amount of CO₂ during aircraft ground operations. We designed a series of four single-stage compression heat pump modules and evaluated various HydroFluoroOlefin (HFO) refrigerants. R1234ze(E) was selected as the most suitable refrigerant based on both the Coefficient of Performance (COP) and the maximum pressure ratio of the system. Additionally, we analyzed the performance of the designed heat pump cycle using 10 years of weather data from Incheon International Airport. As a result, we confirmed that the designed heat pump system could reduce CO₂ emissions by up to 62% compared to the conventional APU system, demonstrating the technical and environmental feasibility of the PCA heat pump system.