Simulation analysis on energy consumption and economy of CPU cooling system based on loop heat pipe for data center

The existing computer room air conditioner (CRAC) system hardly satisfies the rapidly increasing cooling demand of the server's CPU with high heat flux, and it has ultra-high refrigerating energy consumption. As a solution, a water-cooled loop heat pipe (LHP) system can be adapted to cool the CPU in the data center and decrease refrigerating energy consumption. In this study, a Hybrid cooling system combining a water-cooled LHP system and a water-cooled CRAC system is proposed, and the system energy model is developed to analyze its annual energy consumption and economy. Based on a case data center using a lake water source, the effects of system setting points on energy consumption are investigated. The results show the Hybrid system has a considerable energy saving rate of 34.9%-52.4% than the conventional CRAC system. Meanwhile, the annual energy consumption of the Hybrid system declines substantially with increasing CPU power ratio, while it drops slightly with increasing CPU safety temperature. Additionally, the economic analysis illustrates that although the initial investment of Hybrid cooling system is 44.13%-77.74% higher than CRAC system, the dynamic payback periods are 2.48-6.64 years for system retrofit under different operating stages, and the life cycle cost savings are 22.06%-36.45%.