| Title |
An Experimental Study on Energy Consumption in Air and Liquid Cooling Systems for Data Centers |
| Authors |
변상우(Byeon, Sangwoo) ; 조진균(Cho, Jinkyun) |
| DOI |
https://doi.org/10.5659/JAIK.2026.42.4.321 |
| Keywords |
Data Center; Air Cooling System; Liquid Cooling System; In-situ Measurement; Energy Consumption; PUE |
| Abstract |
With the rapid deployment of high-density IT equipment, data centers face increasing cooling energy demands while maintaining stable
thermal operation. Although immersion liquid cooling is considered a promising alternative to conventional air cooling, experimental
comparisons under a consistent system boundary remain limited. This study compares the energy consumption and cooling efficiency of a
fan-wall unit (FWU)-based air-cooling system and a single-phase immersion liquid-cooling system, both sharing an air-cooled chiller (ACC) as
the heat source. Mock-up tests were conducted under summer outdoor conditions with dry-bulb temperatures ranging from 24 to 30°C and
fixed setpoints. Component power consumption was measured to evaluate power usage effectiveness (PUE) under identical IT thermal load
conditions. The air-cooling system exhibited periodic PUE fluctuations due to ACC on?off control, ranging from 1.16 to 1.61~1.62, with
transient peaks reaching 1.75~1.80. In contrast, the immersion system maintained a stable and narrow PUE range of 1.25 to 1.29. Total
energy consumption was 15,961 kWh for air cooling and 7,498 kWh for liquid cooling, with ACC power accounting for 77~80 percent of
total energy use in both systems. In the air-cooling configuration, auxiliary energy consumption was primarily attributed to pumps at 19
percent and FWU fans at 4 percent. In the immersion system, the heat-source pump accounted for 8 percent, the CDU for 7 percent, and
the load pump for 5 percent. Overall, immersion cooling achieved an average PUE of approximately 1.27, representing a 15.3 percent
improvement over air cooling, which averaged approximately 1.50. In addition to lower energy consumption, immersion cooling demonstrated
improved operational stability. |