Experimental study on thermal performance of a single-phase immersion cooling unit for high-density computing power data center

Traditional air-cooling systems cannot meet special requirements of high-density computing power data centers (DCs). The single-phase immersion cooling (SPIC) is considered as one of the best ways to effectively cool highdensity computing power DC cabinets. In this study, a SPIC unit was experimentally investigated with dielectric fluid Noah 3000D under a designed heat load of 20 kW. The impact of the cooling water flow rate qv2 on the thermal characteristics, flow resistance and power consumption of the SPIC unit were investigated. The results show that the temperatures of both the coolant and cooling water decrease with the increase of qv2, but the temperature difference of coolant increases with the increase of qv2. An increase in coolant temperature difference means an increase in temperature non-uniformity. The increase in qv2 also leads to an increase in system flow resistance. In this experiment, the pressure loss of the heat exchanger and pipelines on the coolant side, account for about 56 % and 44 %, respectively. The power usage effectiveness of the cooling system in DC (cPUE) and coefficient of performance (COP) of the SPIC unit vary in the range of 1.08-1.09 and 5.69-7.21, respectively. Moreover, it is found that simply increasing qv2 cannot significantly improve the heat exchange of SPIC units, but will increase system's energy consumption to a certain extent. The present study mainly focuses on the laboratory experimental test on the SPIC unit, and the related conclusions are significant to the design and operation of SPIC units in high-density computing power DCs.