Thermodynamic analysis of hybrid cooling system integrated with waste heat reusing and peak load shifting for data center.

Highlights • Integration of spray cooling with waste heat reusing and peak load shifting. • HCS exhibits excellent energy saving, exergy increase and operation cost saving. • Sensitivity analysis shows the importance of spray cooling inlet temperature. • Economic analysis shows a cost payback period as low as 286 days. Abstract A hybrid cooling system aimed at enhancing energy, exergy and economic efficiency of data center is proposed. The proposed system combines a high cooling efficiency spray cooling system, a waste heat reusing absorption chiller and a peak load shifting chilled water storage. This combination is implemented by replacing the condenser of spray cooling system with the generator of absorption chiller, and storing cooling capacity of absorption chiller during off-peak time to supplement the cooling load during on-peak time. A thermodynamic model is developed based on energy and exergy balance. Parametric sensitivity analysis is performed to investigate the effects of spray cooling inlet temperature, chilled water temperature, cooling water temperature and ambient temperature on the energy saving efficiency, exergy efficiency and operation cost. Comparison study and economic analysis are conducted based on Dawning 5000A supercomputer in Shanghai, China. Sensitivity analysis results show that the effect of spray cooling inlet temperature is the largest, while the effects of chilled water temperature and cooling water temperature are the smallest. At appropriate condition, the absorption chiller and chilled water storage could totally eliminated the cooling load of air conditioner during on-peak time. The energy saving efficiency, exergy efficiency and operation cost saving could be up to 51%, 17%, and 71% with the cost payback period as low as 286 days. [ABSTRACT FROM AUTHOR]