Power Density in the Context of Two-Phase Immersion Cooling

Abstract

Power density has been used to describe the capability of a data center. Achieving harmony between space and power has always been a challenge for data center administrators. Studies demonstrate when the average power density is above 7kW per rack, the space utilization by IT equipment drops to almost 50% of the total white space (the area dedicated to IT equipment and infrastructure). The remaining space is occupied by the cooling equipment required for optimal operation of the housed IT equipment in the racks. With the increasing use of deep learning and artificial intelligence, the different cooling methods like air cooling, cold plate cooling and single-phase immersion cooling are reaching their limits and require more white space. The improved efficiency of the two-phase immersion cooling technique may offer simplicity in facility design compared to traditional cooling and provide a means for cost savings. Submerging servers and IT equipment in a dielectric liquid enables substantial energy savings today and accommodates growing load densities for future facilities. This paper is a first attempt at addressing the overview of power density from the two-phase immersion cooling perspective. The paper compares the dedicated space requirement for air cooling with immersion cooling at higher densities. At 3kW/m2, a typical air-cooled data center floor space density, the actual electronics in a typical data center would fill only the bottom 5mm of the building which is often several stories tall. The P2PIC can increase floor space density 6 times or more while simplifying server design and reducing facility capital and operating costs. At higher densities, the cost of fluid per cost of electronics becomes negligible.