Experimental study of pump-driven chip-level two-phase cooling system for data centres

In this study, we proposed and designed a pump-driven chip-level two-phase cooling system (PCTCS) and experimentally demonstrated that it can directly cool central processing units in data centres (DCs). The operation of the PCTCS involves an internal refrigerant cycle (IRC) and an external water cycle (EWC). Within the IRC, multiple mini-channel evaporators enable the dissipation of heat from the CPUs in the servers through a plate heat exchanger to initiate the EWC, which is followed by the dissipation of the heat to the environment. We performed experiments to systematically analyze the effects of key operation parameters on PCTCS performance of the IRC. The results indicated that the average and the highest core temperature of the CPUs were 76.3 degrees C and 79.0 degrees C, respectively, under extremely harsh heat dissipation conditions. The key driving component of the PCTCS is a refrigerant pump with high energy efficiency ratio (EERp) defined as ratio of heat dissipated by the power of the refrigerant pump. The EERp was 17-18 when the CPUs were at 0% load and 38-42 and 68-76 when the CPUs were at 50% and 100% loads, respectively. Moreover, optimizing the flow resistance of the IRC can improve the performance of the PCTCS.