Theoretical framework and thermodynamic performance of a scroll compressor with hybrid profiles for electric vehicle heat pumps

Abstract Heat pumps are critical for enhancing the driving range of electric vehicles. Conventional scroll compressors suffer low efficiency and poor adaptability under extreme conditions, leading to insufficient heating and cooling performance and significant energy consumption. To address this issue, this study presented a theoretical framework for hybrid scroll profiles, demonstrating a compressor with fewer wraps and larger built-in volume ratio. The impact of base and modified scroll profile on geometric performance was analyzed. Numerical simulations were performed to investigate the refrigerant flow distribution and thermodynamic characteristics of the compressor. Furthermore, a performance prediction model for isentropic and volume efficiencies was developed using the Response Surface Methodology (RSM), revealing strong nonlinear interactions between operating parameters. The results show that increasing the modified angle alters the connection between the base and modified scroll profiles, impacting compression ratio and chamber volume. Flow in the working chamber is asymmetric, with high vorticity regions concentrated at clearances and the tail of scroll wraps. As the pressure ratio increases, thermal losses become more significant, resulting in a 6.9% decrease in isentropic efficiency. In addition, the increase in rotational speed has a more pronounced effect on volume efficiency, improving it more than isentropic efficiency. Further analysis identifies an optimal combination of operating parameters, achieving a predicted isentropic efficiency of 77.6% and volume efficiency of 88.1%.