Comparative Study of Single-Phase Immersion Cooled Two Socket Server in Tank and Sled Configurations

Abstract

Submerging a cluster of servers inside a large tank is the customary way of employing single-phase immersion cooling. But this approach requires a complete renovation of existing air-cooled infrastructure. A practical approach to convert an air-cooled data center to immersion cooled data center can be retaining the rack and server arrangements and supplying each server with immersion liquid in sled configuration – retaining horizontal position. The present study aims at characterizing the thermal performance of a 2-socket server in sled and tank configurations using CFD. In the tank configuration model, the server is immersed vertically with the coolant supply from bottom to top as in the case of a typical single-phase immersion deployments. In the sled configuration, the server orientation is retained (horizontally) and the fluid supply is modeled as an inlet and outlet manifold connected to the same side of the server. The CFD modeling approach is aimed to determine the heat transfer behavior of the server in two configurations being looked at was done for a commercially available dielectric immersion liquid, EC 110. A detailed baseline geometry of the server was first simplified, considering only the components that are significant source of heat and/or impact the server flow characteristics. Some of the components considered for analysis include CPU, storage drives and memory modules. The performance of the server in two configurations is compared to determine the efficiency of both the server configurations while ensuring the components do not exceed their respective thermal threshold. Component temperatures are obtained by varying the coolant flow rates and dielectric temperatures.