基于不完全过热循环的制冷系统低频运行性能的研究
Research on Low-frequency Operational Performance of Refrigeration System based on Incomplete Overheat Cycle

本文以制冷系统不完全过热循环（从压缩机吸气过热至吸气带液）为基础，通过将滚动转子式压缩机分别运行于不同的低频工况下，研究了性能系数、制冷量、压缩比、压缩机功耗、电效率及排气温度等各项制冷系统性能参数的变化特性，提出了该特性下的最佳优化控制策略。结果表明：可适当降低压缩机运行频率并将干度短期控制在0.98≤x <1，此时制冷量相比于常规过热度控制工况（5~10 K）提升8.3%~16.6%，性能系数COP提升12.5%~15%。此外，压缩机电效率仅较常规过热度控制工况降低0.3%~0.7%，且实验最低频率（25 Hz）下的电效率值最大；实验最低频率下，节能效果显著，压比进一步降低，排气温度大幅减小，x<0.90时降幅达到40.3%。
Based on the incomplete superheating cycle of a refrigeration system (from suction superheat of the compressor to two-phase compression), the characteristics of the change in the performance of a refrigeration system, such as the coefficient of performance (COP), refrigeration capacity, pressure ratio, compressor power consumption, electric efficiency, and exhaust temperature, are investigated by running the rolling rotor compressor in different low-frequency conditions. An optimal control strategy is then put forward. The results show that if the compressor operating frequency is properly reduced and the quality of refrigerant is controlled at 0.98 ≤ x < 1 for a short time, the cooling capacity would be increased by 8.3% to 16.6% compared to the conventional superheat control conditions (5–10 K), and the COP would increase by 12.5%–15%. In addition, the electrical efficiency of the compressor was only 0.3%–0.7% lower than that of the conventional superheat control condition, and the electrical efficiency at the lowest frequency (25 Hz) in the experiment was the largest. At the lowest frequency in the experiment, the energy-saving effect was significant, and the pressure ratio was further reduced. The temperature of the exhaust gas was greatly reduced by 40.3% when x<0.90