Research on Design and Optimization of Economic Operation for Indirect Liquid Cooling System in Data Center Servers

With the rapid development of data centers, significant energy consumption challenges have emerged, with cooling system energy consumption accounting for over 30%. Traditional air cooling, limited by airflow organization issues, struggles to meet the cooling demands of high heat flux density chips. Although liquid cooling technology exhibits superior cooling performance, it often leads to high system power consumption due to design and flow matching factors. Therefore, conducting energy-saving optimization of liquid cooling systems holds significant importance. This paper establishes a piping network model for a cabinet-level indirect liquid cooling system, incorporating the heat flow method and piping network fluid dynamics–resistance balance relationships to establish overall system flow and heat transfer constraints. Based on this, optimization analyses are conducted for cabinet liquid cooling systems under centralized and distributed pump configurations. For centralized pump configurations with a constant thermal load, a Lagrangian function is established to minimize system power consumption, and the optimal pump operating frequency is determined using variational principles. When the cooling water temperature rises from 20 °C to 24 °C, the total power consumption increases by 1.55 times. Placing a server with a specific load of 1.2 kW at the bottom of the cabinet rather than the top results in a 34.4% energy savings. With a constant total pump power consumption, a Lagrangian function is established to maximize the system thermal load, and the optimal pump operating frequency is determined. When the cooling water inlet temperature increases by 2 °C, the total thermal load decreases by 4.9%. Servers with higher thermal loads should be placed nearby to make the cooling system more energy-efficient. Comparisons reveal that as the total system thermal load increases from 4.0 kW to 6.0 kW, the distributed pump configuration achieves an average energy savings of 2.5 W, with a maximum savings of 7.09 W, compared to the centralized pump configuration.