Multi-criteria thermoeconomic and thermodynamic assessments of the desalination-integrated two-phase liquid-immersion data center cooling system

The waste heat management of the data center cooling systems has a significant share in the energy-efficient operations of the data centers. In this study, a new hybrid desalination-data center cooling system is proposed to reduce the cost drawback of the waste heat in the data center cooling operations. A two-phase liquid-immersion cooling unit is selected as the data center cooling method with the cooling load range of 0.7 to 1.5 kW. It is a promising solution thanks to the high heat flux removal performance but there is still a lack of research about waste heat management. The waste heat of the immersion cooling system is used to heat up the feed side of the desalination module. A direct contact membrane distillation system as preferred as the desalination module with the membrane area range of 5 to 75 cm(2). The proposed hybrid system is investigated according to the thermodynamic, economic, and thermoeconomic aspects. The thermoeconomic assessment is done concerning the unique exergy-cost matrix of the original design. The maximum thermal and exergy efficiencies are found as 64.5% and 53.7%, respectively. The daily distilled water rate can reach 6.13 kg at the highest cooling load and membrane area. Compared to the stand-alone data center cooling operation, the hybrid system has higher capital and operation costs. The payback period is found 3.72 years that means the proposed system is economically feasible for real applications. Also, the levelized product cost of the hybrid design is calculated in the range of 2.69 to 5.33 SGD/h. In the multiobjective optimization study, the best trade-off point is decided at the cooling load of 1.1 kW whilst the membrane area varies between 5.12 and 5.19 cm(2).