The Inevitable Shift to Liquid Cooling in Data Centers

ABSTRACT The accelerating expansion of data centers have heightened the demand for cooling systems that are both efficient and sustainable. This paper examines the performance, safety, and compatibility of three immersion-cooling fluids: a hydrocarbon oil, Thermasolv™ CF2 (a fluorinated single-phase fluid), and Thermasolv™ IM6 (a fluorinated two-phase fluid). Traditionally, air-cooled systems have had limitations in managing high-density workloads. Air-cooled data centers contribute significantly to energy consumption, water usage, and operational costs. As artificial intelligence (AI), high-performance computing, and hyperscale cloud services expand, two-phase immersion cooling has emerged as a viable alternative. This technology immerses IT hardware in dielectric heat-transfer fluids, allowing for significantly improved thermal management, reduced reliance on mechanical refrigeration, and improved Power Usage Effectiveness (PUE). The favorable characteristics of most dielectric fluids allow for optimal surface contact which contributes to a superior heat transfer performance. Case studies demonstrate that immersion cooling can reduce cooling energy consumption related to air handling systems and pumps by up to 40% and support rack densities exceeding 100 kW which exceed the limits of air-cooled systems. The need for increased data center capacity has made efficient and sustainable two-phase cooling solutions a critical priority.