低负荷条件下水冷制冷机间歇运行分析*
Intermittent operation analysis of water-cooled chillers under low load conditions
摘要：
水冷制冷机在低负荷条件下运行时，供回水温差小，制冷机运行效率低、能耗高，制冷机启停频繁。在分析制冷机调节控制的基础上，提出了低负荷条件下制冷机间歇运行控制策略。以武汉轨道交通某地铁站的空调水系统为对象，对该间歇运行控制策略进行了验证。典型日的夜间运行结果表明：制冷机采用间歇运行控制策略相比于既有运行控制策略，过渡季和制冷季水系统节能率分别为55.4%和51.8%；过渡季制冷机的启停次数由原来的19次减少至12次，制冷季制冷机的启停次数由原来的6次减少至5次。实践证明，该策略可以提高制冷机运行效率，缩短制冷机运行时间，节能效果显著，同时可减少低负荷条件下制冷机的启停次数，保护制冷机，延长制冷机的使用寿命。
Abstract：
The water-cooled chiller features the small temperature difference between supply and return water, low operation efficiency, high energy consumption and frequent shutdown when operating under low load conditions. Based on the analysis of chiller regulation and control, proposes an intermittent operation control strategy for chillers under low load conditions. Taking the air conditioning water system of an underground railway station of Wuhan rail transit as an example, verifies the intermittent operation control strategy. The results of night operation on typical days show that compared with the existing operation control strategy, the energy saving rate of water system in the transition season and the cooling season using the intermittent operation control strategy is 55.4% and 51.8% respectively. In the typical day of the transition season, the on/off number of the chiller reduces from 19 to 12, while in cooling season, the number reduces from 6 to 5. The implementation results demonstrate that this strategy can improve the chiller efficiency and shorten the chiller operation time with significant energy saving effect. At the same time, the strategy can reduce the on/off number for protecting the chiller and prolonging the chiller life.
Keywords:water-cooled chiller, low load operation, on/off control, intermittent operation, control strategy, energy saving effect