The liquid cooling system is the most promising active cooling system which generally uses water, ethylene glycol, or oil as a working fluid , , , , , . The cooling efficiency of liquid is far more extensive than air because of its higher heat transfer of coefficient.
It was shown that the liquid-cooled UPS reduced the yearly energy consumption of the cooling system by at least 14% compared to the air-cooled UPS. Table 12. Cooling-system consumption details at UPS level for air-cooled unit and liquid-cooled unit. 6.2. On infrastructure cooling system (heat-rejection system) level
A mechanical cooling (MC) system with chillers, as required with air-cooled UPS units, and an indirect free-cooling system that could be used with liquid-cooled UPS units were deployed. The comparison highlights the impact of the autonomous liquid-cooled UPS on the energy savings for a data centre.
This paper presents a new liquid-cooling technology for uninterruptible power supply (UPS) units in which an air-cooling system is combined with an indirect water-cooling system based on direct-chip cooling. This cooling architecture provides more opportunities to use free cooling as the main or only cooling system for optimal data centres (DCs).
Nonetheless, the compactness of the liquid cooling TMS has paid less attention in the literature, which plays a vital role in the specific energy of ESSs. In this study, a liquid-based TMS is designed for a prismatic high-power lithium-ion capacitor (LiC).
Liquid-cooled units benefit from several advantages; the cooling system is operated at a high water temperature up to 40–60 ° C @ 20 K with a low liquid supply flow rate (16.7 l/min), for better use of on-site free-cooling. A decrease in ventilation electrical consumption results in a low OPEX.