Application and simulation of IEC water chillers for summer free cooling in data centers

Abstract

Free cooling is regarded as the most effective way to reduce the energy consumption of the cooling system in data centers. This study proposes a novel water-medium indirect evaporative cooling (IEC) chiller used in a data center to achieve free cooling throughout the year as an alternative to electrical chillers. Field tests and numerical modeling of the IEC water chillers are both reported to evaluate the performance and efficiency. This paper first-time reports on the application of IEC water chillers to deliver year-round free cooling for a data center in Changji, China. The wet-bulb efficiency of the tested chiller is measured as 120% to 152.8% and the dew-point efficiency is 27% to 62.7%. A numerical model is established to verify the operating conditions, and some common operational optimizations are pointed out in this test for energy savings. PUE can be reduced to 1.212 after the optimization. More future performance predictions of the IEC water chillers are studied when the data center load rate increases and when the local weather changes in a year to discuss the year-round availability. For further study, the performance of IEC water chillers in different climate regions is also forecasted. The results indicate that it’s an effective way for IEC to achieve free cooling in regions where natural cold resources are abundant. In this study, the field test performance and prediction of IEC water chillers are provided as a typical and practical application as the natural cooling source in data centers in hot and dry areas.