由马驰原等撰写的论文On the existence of optimal intermediate temperature in two-stage vapor compression systems在Energy 2025年第315卷在线发表。论文发现两级蒸气压缩式制冷/热泵系统的最优中间压力表现出复杂特性，最优中间温度（压力）不一定存在。通过理论推导和数值模拟，论证了使用单一制冷剂的两级蒸气压缩系统是否存在最优中间温度与压缩机等熵效率、制冷剂热物性有关。论文从热力学原理上突破了对两级蒸气压缩系统的一贯认知（存在最优中间温度），从应用角度也具有重要意义，可指导相关系统设计及运行策略。

论文链接

论文摘要：

Vapor compression systems are widely used in air conditioning, refrigeration, and heating, with two-stage systems often used in applications where a large temperature lift is required to improve energy efficiency. Optimization of the intermediate temperature (T_int) is critical to maximize the system energy performance. This paper investigates the existence of optimal T_int in two-stage systems. A general thermodynamic model is developed using the cycle separation method, followed by theoretical derivation and numerical validation. The results reveal four different functional relations between the coefficient of performance (COP) and T_int, which are influenced by isentropic efficiencies, operating conditions, and thermodynamic properties of refrigerants. An optimal T_int exists only when the isentropic efficiencies of both stages are comparable and not excessively low. Conversely, significant differences in isentropic efficiencies or both low efficiencies result in the absence of optimal T_int. This paper introduces a general thermodynamic model for two-stage systems and identifies four unique T_int-COP relations, providing broader insights compared to previous studies that predominantly focused on specific configurations. Accordingly, some fundamental recommendations for the design and operation of two-stage systems are made.