Impact of Coolant Temperature on Boiling Chamber Performance for Cooling Electronic Chips

Data centers in their quest for ever-increasing processing power are generating more heat than ever before. This heat, if not effectively managed, can lead to equipment failure, reduced performance, and significant financial losses. The development of efficient cooling systems is therefore a pressing need. While numerous two-phase techniques have been developed to meet this escalating heat dissipation demand, their compatibility with free-to-air cooling, especially at higher temperatures, remains a challenge. To address this issue, we propose the use of boiling chambers employing subcooled boiling and submerged condensation mechanisms, an innovative solution that promises effective heat dissipation. This study delves into the potential of higher coolant temperatures to enhance the thermal performance of a boiling chamber. Specifically, we experimentally investigated the effects of coolant temperatures ranging from 20°C to 50°C on the thermal performance of the boiling chamber, with water as the working fluid. The use of higher coolant temperatures could enable the use of air-cooled condensers, potentially reducing or even eliminating water consumption in cooling towers. A consistent coolant flow rate of 0.035 kg/s was maintained for all test cases, along with a volume fill rate of 45 ml and an initial pressure of 12 kPa. The experimental setup included a one-pass parallel flow heat exchanger with 82 x 68 x 25 mm dimensions, designed to manage heat loads up to 822 W (75 W/cm2). The results indicated that with a volume fill rate of 45 ml of water, the system managed a heat dissipation rate of 700 W with a heat flux of 62 W/cm² while maintaining a surface temperature below 80°C with an inlet coolant temperature of 20°C. For the experimental case with a 50°C coolant temperature, the surface temperature rose to 95°C while dissipating a similar amount of heat. The thermal resistance , defined as the ratio of heat load dissipated divided by the difference between the surface temperature and average coolant temperature, remained about 0.1 K/W at higher heat loads past 500 W for all coolant temperatures. The findings from the current work show the boiling chamber's effectiveness in dissipating high heat flux even with elevated coolant temperatures. The results postulate that the novel boiling chamber can be integrated with free-to-air cooling systems in data centers to enable year-round and efficient thermal management of high-performance computing processors, significantly impacting the sustainability of these data centers.