Air Flow Pattern and Path Flow Simulation of Airborne Particulate Contaminants in a High-Density Data Center Utilizing Airside Economization

Author(s):  
Gautham Thirunavakkarasu ◽  
Satyam Saini ◽  
Jimil Shah ◽  
Dereje Agonafer

The percentage of the energy used by data centers for cooling their equipment has been on the rise. With that, there has been a necessity for exploring new and more efficient methods like airside economization, both from an engineering as well as business point of view, to contain this energy demand. Air cooling especially, free air cooling has always been the first choice for IT companies to cool their equipment. But, it has its downside as well. As per ASHRAE standard (2009b), the air which is entering the data center should be continuously filtered with MERV 11 or preferably MERV 13 filters and the air which is inside the data center should be clean as per ISO class 8. The objective of this study is to design a model data center and simulate the flow path with the help of 6sigma room analysis software. A high-density data center was modelled for both hot aisle and cold aisle containment configurations. The particles taken into consideration for modelling were spherical in shape and of diameters 0.05, 0.1 and 1 micron. The physical properties of the submicron particles have been assumed to be same as that of air. For heavier particles of 1 micron in size, the properties of dense carbon particle are chosen for simulating particulate contamination in a data center. The Computer Room Air Conditioning unit is modelled as the source for the particulate contaminants which represents contaminants entering along with free air through an air-side economizer. The data obtained from this analysis can be helpful in predicting which type of particles will be deposited at what location based on its distance from the source and weight of the particles. This can further help in reinforcing the regions with a potential to fail under particulate contamination.

Author(s):  
Satyam Saini ◽  
Pardeep Shahi ◽  
Pratik V Bansode ◽  
Jimil M. Shah ◽  
Dereje Agonafer

Abstract Continuous rise in cloud computing and other web-based services propelled the data center proliferation seen over the past decade. Traditional data centers use vapor-compression-based cooling units that not only reduce energy efficiency but also increase operational and initial investment costs due to involved redundancies. Free air cooling and airside economization can substantially reduce the IT Equipment (ITE) cooling power consumption, which accounts for approximately 40% of energy consumption for a typical air-cooled data center. However, this cooling approach entails an inherent risk of exposing the IT equipment to harmful ultrafine particulate contaminants, thus, potentially reducing the equipment and component reliability. The present investigation attempts to quantify the effects of particulate contamination inside the data center equipment and ITE room using CFD. An analysis of the boundary conditions to be used was done by detailed modeling of IT equipment and the data center white space. Both 2-D and 3-D simulations were done for detailed analysis of particle transport within the server enclosure. An analysis of the effect of the primary pressure loss obstructions like heat sinks and DIMMs inside the server was done to visualize the localized particle concentrations within the server. A room-level simulation was then conducted to identify the most vulnerable locations of particle concentration within the data center space. The results show that parameters such as higher velocities, heat sink cutouts, and higher aspect ratio features within the server tend to increase the particle concentration inside the servers.


Author(s):  
Satyam Saini ◽  
Kaustubh K. Adsul ◽  
Pardeep Shahi ◽  
Amirreza Niazmand ◽  
Pratik Bansode ◽  
...  

Abstract Modern-day data center administrators are finding it increasingly difficult to lower the costs incurred in mechanical cooling of their IT equipment. This is especially true for high-performance computing facilities like Artificial Intelligence, Bitcoin Mining, and Deep Learning, etc. Airside Economization or free air cooling has been out there as a technology for a long time now to reduce the mechanical cooling costs. In free air cooling, under favorable ambient conditions of temperature and humidity, outside air can be used for cooling the IT equipment. In doing so, the IT equipment is exposed to sub-micron particulate/gaseous contaminants that might enter the data center facility with the cooling airflow. The present investigation uses a computational approach to model the airflow paths of particulate contaminants entering inside the IT equipment using a commercially available CFD code. A Discrete Phase Particle modeling approach is chosen to calculate trajectories of the dispersed contaminants. Standard RANS approach is used to model the airflow in the airflow and the particles are superimposed on the flow field by the CFD solver using Lagrangian particle tracking. The server geometry was modeled in 2-D with a combination of rectangular and cylindrical obstructions. This was done to comprehend the effect of change in the obstruction type and aspect ratio on particle distribution. Identifying such discrete areas of contaminant proliferation based on concentration fields due to changing geometries will help with the mitigation of particulate contamination related failures in data centers.


2018 ◽  
Vol 65 (10) ◽  
pp. 1395-1399 ◽  
Author(s):  
Gyu-Seob Jeong ◽  
Jeongho Hwang ◽  
Hong-Seok Choi ◽  
Hyungrok Do ◽  
Daehyun Koh ◽  
...  

2020 ◽  
Vol 168 ◽  
pp. 106495
Author(s):  
Xiaolei Yuan ◽  
Xinjie Xu ◽  
Jinxiang Liu ◽  
Yiqun Pan ◽  
Risto Kosonen ◽  
...  

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Oluwaseun Awe ◽  
Jimil M. Shah ◽  
Dereje Agonafer ◽  
Prabjit Singh ◽  
Naveen Kannan ◽  
...  

Abstract Airside economizers lower the operating cost of data centers by reducing or eliminating mechanical cooling. It, however, increases the risk of reliability degradation of information technology (IT) equipment due to contaminants. IT Equipment manufacturers have tested equipment performance and guarantee the reliability of their equipment in environments within ISA 71.04-2013 severity level G1 and the ASHRAE recommended temperature-relative humidity (RH) envelope. IT Equipment manufacturers require data center operators to meet all the specified conditions consistently before fulfilling warranty on equipment failure. To determine the reliability of electronic hardware in higher severity conditions, field data obtained from real data centers are required. In this study, a corrosion classification coupon experiment as per ISA 71.04-2013 was performed to determine the severity level of a research data center (RDC) located in an industrial area of hot and humid Dallas. The temperature-RH excursions were analyzed based on time series and weather data bin analysis using trend data for the duration of operation. After some period, a failure was recorded on two power distribution units (PDUs) located in the hot aisle. The damaged hardware and other hardware were evaluated, and cumulative corrosion damage study was carried out. The hypothetical estimation of the end of life of components is provided to determine free air-cooling hours for the site. There was no failure of even a single server operated with fresh air-cooling shows that using evaporative/free air cooling is not detrimental to IT equipment reliability. This study, however, must be repeated in other geographical locations to determine if the contamination effect is location dependent.


Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6147
Author(s):  
Jinkyun Cho ◽  
Jesang Woo ◽  
Beungyong Park ◽  
Taesub Lim

Removing heat from high-density information technology (IT) equipment is essential for data centers. Maintaining the proper operating environment for IT equipment can be expensive. Rising energy cost and energy consumption has prompted data centers to consider hot aisle and cold aisle containment strategies, which can improve the energy efficiency and maintain the recommended level of inlet air temperature to IT equipment. It can also resolve hot spots in traditional uncontained data centers to some degree. This study analyzes the IT environment of the hot aisle containment (HAC) system, which has been considered an essential solution for high-density data centers. The thermal performance was analyzed for an IT server room with HAC in a reference data center. Computational fluid dynamics analysis was conducted to compare the operating performances of the cooling air distribution systems applied to the raised and hard floors and to examine the difference in the IT environment between the server rooms. Regarding operating conditions, the thermal performances in a state wherein the cooling system operated normally and another wherein one unit had failed were compared. The thermal performance of each alternative was evaluated by comparing the temperature distribution, airflow distribution, inlet air temperatures of the server racks, and recirculation ratio from the outlet to the inlet. In conclusion, the HAC system with a raised floor has higher cooling efficiency than that with a hard floor. The HAC with a raised floor over a hard floor can improve the air distribution efficiency by 28%. This corresponds to 40% reduction in the recirculation ratio for more than 20% of the normal cooling conditions. The main contribution of this paper is that it realistically implements the effectiveness of the existing theoretical comparison of the HAC system by developing an accurate numerical model of a data center with a high-density fifth-generation (5G) environment and applying the operating conditions.


Author(s):  
Magnus K. Herrlin ◽  
Michael K. Patterson

Increased Information and Communications Technology (ICT) capability and improved energy-efficiency of today’s server platforms have created opportunities for the data center operator. However, these platforms also test the ability of many data center cooling systems. New design considerations are necessary to effectively cool high-density data centers. Challenges exist in both capital costs and operational costs in the thermal management of ICT equipment. This paper details how air cooling can be used to address both challenges to provide a low Total Cost of Ownership (TCO) and a highly energy-efficient design at high heat densities. We consider trends in heat generation from servers and how the resulting densities can be effectively cooled. A number of key factors are reviewed and appropriate design considerations developed to air cool 2000 W/ft2 (21,500 W/m2). Although there are requirements for greater engineering, such data centers can be built with current technology, hardware, and best practices. The density limitations are shown primarily from an airflow management and cooling system controls perspective. Computational Fluid Dynamics (CFD) modeling is discussed as a key part of the analysis allowing high-density designs to be successfully implemented. Well-engineered airflow management systems and control systems designed to minimize airflow by preventing mixing of cold and hot airflows allow high heat densities. Energy efficiency is gained by treating the whole equipment room as part of the airflow management strategy, making use of the extended environmental ranges now recommended and implementing air-side air economizers.


2006 ◽  
Vol 21 (2-3) ◽  
pp. 227-238 ◽  
Author(s):  
Abdlmonem H. Beitelmal ◽  
Chandrakant D. Patel

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