Experimental Analysis for Optimization of Thermal Performance of a Server in Single Phase Immersion Cooling

Abstract Liquid immersion cooling of servers in synthetic dielectric fluids is an emerging technology which offers significant cooling energy savings and increased power densities for data centers. A noteworthy advantage of using immersion cooling is high heat dissipation capacity which is roughly 1200 times greater than air. Other advantages of dielectric fluid immersion cooling include high rack density, better server performance, even temperature profile, reduction in noise etc. The enhanced thermal properties of oil lead to the considerable savings in both upfront and operating cost over traditional methods. In this study, a server is completely submerged in a synthetic dielectric fluid. Experiments are conducted to observe the effects of varying the volumetric flow rate and oil inlet temperature on thermal performance and power consumption of the server. Various parameters like total server power consumption, the temperature of all heat generating components like Central Processing Unit (CPU), Dual in Line Memory Module (DIMM), input/output hub (IOH) chip, Platform Controller Hub (PCH), Network Interface Controller (NIC) are measured at steady state. Since this is an air-cooled server, the results obtained from the experiments will help in proposing better heat removal strategies like heat sink optimization, better ducting and server architecture. Assessment has been made on the effect of thermal shadowing caused by the two CPUs on the nearby components like DIMMs and PCH.