Refined one-dimensional modeling and experimental validation of scroll compressor with vapor injection for electric vehicles

Abstract

Vapor injection technology represents a highly promising avenue for enhancing the efficiency of heat pump systems within electric vehicles, especially in challenging cold ambient conditions. Although a simplified isentropic process is commonly employed to assess the thermodynamic functioning of scroll compressors with vapor injection (SCVI), it diverges significantly from actual operational dynamics. This study introduces a sophisticated 1D mathematical model that incorporates key factors such as internal leakage and thermal losses, thereby providing a more accurate representation of SCVI's operational realities. The research includes comprehensive performance evaluations of a short wrap profile SCVI, with a specific focus on low-temperature ambient conditions, supported by rigorous experimental validation. Comparative analyses against non-injection scenarios reveal notable enhancements, including a maximum 17.2 % increase in mass flow, a 10.5 % rise in heating capacity, and a 2.15 % improvement in heating COP. Both the simplified isentropic process calculation model and the enhanced 1D mathematical model are utilized to analyze compressor operations. The integration of internal leakage and heat loss considerations significantly narrows the gap between calculated and experimental results for heating capacity and discharge temperature, reducing discrepancies from nearly 20 % to a mere 4 %. This refined mathematical model demonstrates a high level of alignment with experimental data, achieving an accuracy within 5 % when assessing the compressor's real-world operational dynamics.