Experimental Investigation Regarding Rack Pressure Resistance on Cooling Performance of a Container Data Center

2019 ◽  
Vol 27 (04) ◽  
pp. 1950038
Author(s):  
Wen-Xiao Chu ◽  
Rui Wang ◽  
Chi-Chuan Wang

This paper experimentally investigates the effect of pressure resistance distribution by using perforated grilles with different porosities ([Formula: see text]%, 58% and 35.4%) in a container data center. The inlet and outlet temperature distribution, rack cooling index (RCI) and supply heat index (SHI) are used to evaluate the cooling performance under semi-contained and fully contained configurations. As a result, the airflow reversal phenomenon at the top cabinets is found, which is especially conspicuous for the case without perforated grilles due to the extremely low pressure resistance in the cabinet. By implementing perforated grilles at lower three cabinets, the airflow reversal can be eliminated, however, it cannot be completely removed. By applying perforated grilles with [Formula: see text]% at the top three cabinets can increase the pressure resistance at the cabinets [Formula: see text] where the airflow reversal is eliminated thoroughly. Yet, the performance of cabinets at rack [Formula: see text] may degrade rapidly due to much stronger hot-exhaust recirculation. Hence, the fully contained configuration is applied. Note that the airflow reversal is more severe for the case without perforated grilles. By arranging the perforated grilles with [Formula: see text] = 35.4%, the corresponding RCI and SHI may reach the ideal values of 100% and zero, respectively. Therefore, the perforated grilles with [Formula: see text] = 35.4% are more reasonable for simulated racks under semi-contained and fully contained configurations when airflow reversal occurs.

Author(s):  
Binfei Zhan ◽  
Shuangquan Shao ◽  
Mi Lin ◽  
Hainan Zhang ◽  
Changqing Tian ◽  
...  

Author(s):  
Junnosuke Okajima ◽  
Atsuki Komiya ◽  
Shigenao Maruyama

The objective of this work is to experimentally and numerically evaluate small-scale cryosurgery using an ultrafine cryoprobe. The outer diameter (OD) of the cryoprobe was 550 μm. The cooling performance of the cryoprobe was tested with a freezing experiment using hydrogel at 37 °C. As a result of 1 min of cooling, the surface temperature of the cryoprobe reached −35 °C and the radius of the frozen region was 2 mm. To evaluate the temperature distribution, a numerical simulation was conducted. The temperature distribution in the frozen region and the heat transfer coefficient was discussed.


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