Effects of mineral oil immersion cooling on IT equipment reliability and reliability enhancements to data center operations

This paper reviews the changes in physical and chemical properties of information technology (IT) equipment materials like polyvinyl chloride (PVC), printed circuit board (PCB) and switching devices due to mineral oil to characterize the interconnect reliability of materials. By submerging all of a server's heat-generating components in a dielectric liquid, creates the attack on reliability issues at the device level. The improved efficiency of mineral oil may offer simplicity in facility design compared to traditional air cooling and provide a means for cost savings. In spite of its improved cooling efficiency and cost savings, a mineral oil immersion cooling technique is still not widely implemented and suppliers are reluctant to jeopardize sales of existing air-based cooling system equipment. Only compelling physics regarding direct immersion cooling is not enough for data center operators. Many uncertainties and concerns persist regarding the effects of mineral oil immersion cooling on information technology equipment reliability. The paper presents useful information regarding the influence of mineral oil on the mechanical properties as well as chemical properties of a material. The changes in properties of mineral oil like kinematic viscosity and dielectric strength are also cited as an important factor and discussed briefly. The changes in mechanical properties like elasticity, hardness, swelling, and creep are being shown in the paper for thermoplastic materials. The chemical reaction between material and mineral oil as a function of time and temperature is also conferred. These are significant factors which are responsible for the reliability and compatibility of a material. The changes or modifications in materials of important parts in physical and chemical manner are also indicated. The relations between different dielectric oils and different materials provide us a comparative analysis for reliability and performance. Oil immersion cooling of data centers offers opportunities for enhanced reliability with even temperature conditions in operations as it minimizes common operational issues like: overheating and temperature swings in the system, fan failures in servers, noise, dust, air quality, corrosion, electrochemical migration, and whiskers will also be addressed. The reliability improvements are comprised of the reduction in corrosion & electrochemical migration like corrosive exposure and moisture reduction, reduction in environmental contamination like dust, debris and particulate reduction, stable and even thermal environment and tin and zinc whisker mitigation. These may lead to infer the significance of oil cooled data centers towards performance and savings in operating cost as per reliability aspect. The literature gathered on the subject and quantifiable data gathered by the authors provide the primary basis for this research document.