System-level experimental investigations of the direct immersion cooling data center units with thermodynamic and thermoeconomic assessments

The study is to perform thermodynamic, economic and thermoeconomic assessments for two different direct immersion cooling data center systems which are the single-phase and the two-phase immersion cooling systems with the operating ranges of 3.2-27.6 kW and 6.8-15.9 kW, respectively. The two-phase cooling system achieves 72-79% better coefficient of performance trends than the single-phase cooling system. According to the present worth method, the replacement and the energy costs are found as the most dominant future cost terms for the two-phase and the single-phase cooling systems, respectively. The annual exergy cost of the two-phase cooling system is found up to 4.91 times the annual energy costs due to the dominant effects of the destruction and loss terms. Moreover, both cooling data center systems are compared to the existing air-cooled data center unit. They are found economically infeasible for the server power rates below 5 kW because of their higher capital investment costs while they become more affordable for higher server power rates with lower future cost terms. (C) 2020 Elsevier Ltd. All rights reserved.