低温热泵多联机启动及运行可靠性研究

Investigation on Start-up and Reliability of Low Temperature Air Source Heat Pump

本文以采用双级压缩二级节流不完全冷却系统的低温热泵多联机作为研究对象,研究机组在低温环境下的压缩机启动性能,以及非稳态运行过程中的系统可靠性。建立了机组低温启动控制逻辑,结合室内外机电子膨胀阀,回油阀和压缩机升频速度控制,实现了机组-35℃稳定启动。在系统可靠性研究中,重点分析了倒流和补气带液现象及其临界状态下的系统参数变化趋势,并在多联机上进行了实验验证。

In this paper the air source heat pump variable refrigerant flow(VRF)of two-stage vapor injection system were analyzed,to investigate the compressor start-up performance at low ambient temperature and the system reliability during unsteady operating process.The start-up control logic of VRF were designed,which combined the control of the electronic expansion valves(EEV),the oil switch valve(SV)and the elevator rate of compressor frequency,to achieve the unit steadily started up at-35℃.In the study on the reliability of the system,the phenomena of the refluence vapor and the enthalpy increasing by vapor injection flowing with liquid,and the trend of the system parameter at their critical state were researched,then it was validated with the experiment in the unit.