Simulation Study of Single-phase Immersion Cooling of a Single Server and a Cluster of Servers in a Tank

Abstract

Immersion cooling of IT equipment is a key liquid cooling technology. The industry now has many commercial implementations of both single-phase immersion cooling using mineral oils and two-phase immersion cooling using engineered fluids such as hydrofluroethers (HFEs) and fluoroketones (FK). Immersion cooling has the benefit of cooling the entirety of the server and does not require additional plumbing within the server equipment. Immersion cooling can provide many of the benefits of water cooling while minimizing the risk and damage associated with water leaks. In this paper we will firstly provide an overview of developments in the industry and technology and then discuss the simulation assessment of i) a single mineral oil immersion cooled 2U server with 2 processors and 4 GPUs and ii) a cluster of mineral oil cooled 2U servers in a tank. The server level simulations will compare the temperatures of key components and flow profiles within the server for a baseline air-cooled server as well as a mineral oil cooled server at different flow velocities. The tank level simulations will focus on tank level simulations of a cluster of oil immersion cooled servers in a large tank. The results show the thermal and flow profiles that are set up within the tank at different bulk pumping rates. The simulations will also explore the impact of server removal for servicing on flow and cooling of the other servers in the tank cluster. This work continues to build on the prior literature on the simulation and experimental work that has been conducted into immersion cooling and explores the impact of fluid properties on server cooling and the cooling of a compute cluster in an immersion cooling tank.