Experimental Characterization of Vertically Split Distribution Wet- Cooling Media Used in the Direct Evaporative Cooling of Data Centers

Author(s):  
Ahmed Al Khazraji ◽  
Ashwin Siddarth ◽  
Mullaivendhan Varadharasan ◽  
Abhishek Guhe ◽  
Dereje Agonafer ◽  
...  
Author(s):  
Azzeddine Laknizi ◽  
Abdellatif Ben Abdellah ◽  
Mustapha Faqir ◽  
Elhachmi Essadiqi ◽  
Said Dhimdi

Author(s):  
Mullaivendhan Varadharasan ◽  
Dereje Agonafer ◽  
Ahmed Al Khazraji ◽  
Jimil Shah ◽  
Ashwin Siddarth ◽  
...  

Direct evaporative cooling (DEC) is widely used in the data center cooling units to maintain the air condition inside the data centers. Often, the flow rate of the water over the wet cooling media in this DEC process is frequently varied to maintain the air condition inside the data centers based on changing weather conditions. Though the adopted method helps to control the air temperature and relative humidity, the scale formation occurs on the surface of wet cooling media due to the frequent variation of the flow rate and deposition of minerals present in the water at low flow rate values, which increases the total weight of the wet cooling media and it can lead to a wet cooling media collapse. In this paper an alternative and simplified method to control the air condition is presented. A vertically split wet cooling media is designed and tested in a commercial CFD tool to analyze the temperature and relative humidity parameters of the inlet and outlet air to the wet cooling media, in this approach the sections of the media can either be completely wet or completely dry which can potentially avoid the scale formation on the surface of the wet cooling media. In addition to the temperature and relative humidity parameters against the air flow rates, the pressure drop and cooling efficiency values for varied air flow rates are studied. The vertically split wet cooling media configurations are achieved by sectioning the media in to equal and unequal sections. In the equal configuration, media has been tested for 0%, 50% and 100% wetting conditions, and in the unequal configuration, media has been tested for 0%, 33%, 66% and 100% wetting conditions. The test results are used to emphasis the advantage of this staged wetting method and gives a possible solution to the scale formation problem on the wet cooling media during the direct evaporative cooling process in the data center.


2018 ◽  
Author(s):  
Abhishek Walekar ◽  
Ashwin Siddarth ◽  
Abhishek Guhe ◽  
Nikita Sukthankar ◽  
Dereje Agonafer

With an increase in the need for energy efficient data centers, a lot of research is being done to maximize the use of Air Side Economizers (ASEs), Direct Evaporative Cooling (DEC), Indirect Evaporative Cooling (IEC) and multistage Indirect/Direct Evaporative Cooling (I/DEC). The selection of cooling configurations installed in modular cooling units is based on empirical/analytical studies and domain knowledge that fail to account for the nonlinearities present in an operational data center. In addition to the ambient conditions, the attainable cold aisle temperature and humidity is also a function of the control strategy and the cooling setpoints in the data center. The primary objective of this study is to use Artificial Neural Network (ANN) modelling and Psychrometric bin analysis to assess the applicability of various cooling modes to a climatic condition. Training dataset for the ANN model is logged from the monitoring sensor array of a modular data center laboratory with an I/DEC module. The data-driven ANN model is utilized for predicting the cold aisle humidity and temperatures for different modes of cooling. Based on the predicted cold aisle temperature and humidity, cold aisle envelopes are represented on a psychrometric chart to evaluate the applicability of each cooling mode to the territorial climatic condition. Subsequently, outside air conditions favorable to each cooling mode in achieving cold aisle conditions, within the ASHRAE recommended environmental envelope, is also visualized on a psychrometric chart. Control strategies and opportunities to optimize the cooling system are discussed.


2002 ◽  
Vol 716 ◽  
Author(s):  
C. L. Gan ◽  
C. V. Thompson ◽  
K. L. Pey ◽  
W. K. Choi ◽  
F. Wei ◽  
...  

AbstractElectromigration experiments have been carried out on simple Cu dual-damascene interconnect tree structures consisting of straight via-to-via (or contact-to-contact) lines with an extra via in the middle of the line. As with Al-based interconnects, the reliability of a segment in this tree strongly depends on the stress conditions of the connected segment. Beyond this, there are important differences in the results obtained under similar test conditions for Al-based and Cu-based interconnect trees. These differences are thought to be associated with variations in the architectural schemes of the two metallizations. The absence of a conducting electromigrationresistant overlayer in Cu technology, and the possibility of liner rupture at stressed vias lead to significant differences in tree reliabilities in Cu compared to Al.


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