Immersion phase-change thermal management system coupled with loop thermosyphons for utilization in data centers cooling

Due to the ever-expanding demand for data center computing power, data center electricity consumption will exceed 1,000 terawatt-h in 2030. Cooling system energy consumption accounts for approximately 40 % of total data center energy consumption while the average power usage effectiveness (PUE) for data centers is 1.8 ∼ 2.0. Therefore, advanced cooling strategies are crucial for reducing data center energy consumption, improving energy utilization, and lowering operating costs. Here, we address the high power consumption challenge in data centers by proposing an immersion phase-change cooling system utilizing loop thermosyphons, which can significantly reduce system PUE and improve energy efficiency. The experimental results indicated an thermal–hydraulic balance was achieved between the pressure difference and thermal resistance at a liquid filling ratio of 65 %. An adiabatic section height of 80 cm minimized thermal resistance while maintain sufficient liquid subcoolings, and a liquid level height of 50 cm efficiently suppressed temperature fluctuations and prevented liquid dry-out. Optimization of the vapor–liquid separation tank volume reduced the temperature fluctuations by 10 ∼ 50 % under the heat load ranging of 120 W ∼ 390 W. Operating at airflow volume of 127 CFM and a heat load of 390 W, this system achieved a PUE as low as 1.038. This study provides a parametric design framework for high-power immersion phase-chase cooling systems, advancing toward the goal of ultra-low energy consumption in data centers.