Experimental study on thermal performance of the novel two-path thermal energy storage for emergency cooling in data center

Emergency cooling system is necessary to guarantee high security for data center. Thermal energy storage is one of the feasible methods for emergency cooling with quick response ability to supply higher thermal safety. To simplify the traditional thermal energy storage system and improve its heat transfer efficiency, the novel twopath latent thermal energy storage unit developed for emergency cooling is experimentally studied. The effects of inlet temperature, flow rate on thermal performance of LTES, including heat transfer rate, accumulated energy, effectiveness and overall heat transfer coefficient, are investigated during both charging and discharging processes. Results from the experimental analysis show that the released energy of system could reach up to 2.9 MJ with the average heat transfer rate 1575W-2286 W. The overall heat transfer coefficient ranges from about 297-660 W/K when the flow rate of HTF varied from 12 to 16 L/min. The experimental LTES is then studied integrated with CRAC for emergency cooling. For air flow rate higher than 300 m3/h, and thermal load lower than 1800 W, the LTES meets 15 min of emergency cooling. The inlet and outlet air temperature of CRAC are successfully controlled under 40.5 degrees C and 23.9 degrees C. The newly designed LTES shows good thermal performance, and provides more flexibility and adaptability for real application in data center.