过冷却回路对多联机性能的影响
Effect of Subcooling Circuit on Performance of Multi-split VRF System

本文实验研究了过冷却回路对多联机制冷和制热性能的影响，并提出多联机过冷却回路的控制策略。结果表明：室内、外机之间的配管越长、负荷率越大及室外机入口水温越高，过冷却回路对多联机制冷量和EER的优化潜力越大；过冷却回路对制热量和制热COP均无显著影响。提出将室外机模块出口过冷度、压缩机排气温度和过冷却换热器节流侧出口过热度作为过冷却回路的开启判据和控制目标参数。
The effect of the subcooling circuit on the cooling and heating performances of a multi-split VRF system was studied experimentally and a control strategy for multi-split VRF system with subcooling circuit is proposed in the paper. The results show that the subcooling circuit has a greater potential for improving the cooling capacity and the EER of the multi-split VRF system when the VRF system has a longer pipeline between the indoor units and the outdoor unit, a larger part-load ratio and a higher inlet water temperature of the outdoor unit, while the subcooling circuit has less influence on the heating capacity and the COP of the multi-split VRF system. Based on the results, a control strategy of the subcooling circuit is proposed, which takes the outlet subcooling degree of the outdoor unit, the compressor discharge temperature and the outlet superheat degree of the bypass stream in the subcooling heat exchanger as decision parameters and control targets of the subcooling circuit