Intermittent operation analysis of water-cooled chillers under low load conditions

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.