scholarly journals A Comparative CFD Study of Two Air Distribution Systems with Hot Aisle Containment in High-Density Data Centers

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.

2021 ◽  
Vol 336 ◽  
pp. 02028
Author(s):  
Lianteng Shen ◽  
Shengpan Qian ◽  
Tianyi Zhai ◽  
Ling Li ◽  
Zhe Li

The current rapid development of cloud computing and networks has put forward new requirements for the construction of new infrastructure such as data centers. This paper compares traditional data centers and high-density data centers, proposes a three-tier infrastructure for high-density data centers, and analyzes the data center environment. To solve the obvious problem of software and hardware heterogeneity in high-density data centers, this paper uses virtualization technology to pool resources in high-density data centers and introduces SOA architecture to manage software and hardware resources hierarchically. Finally, the data center infrastructure and environment matching technology are studied.


Author(s):  
Tianyi Gao ◽  
Emad Samadiani ◽  
Bahgat Sammakia ◽  
Roger Schmidt

Data centers consume a considerable amount of energy which is estimated to be about 2 percent of the total electrical energy consumed in the US, and their power consumption continues to increase every year. It is also estimated that roughly 30–40 percent of the total energy used in a data center is due to the thermal management systems. So, there is a strong need for better cooling methods which could improve the cooling capacity and also reduce energy consumption for high density data centers. In this regard, liquid cooling systems have been utilized to deal with demanding cooling and energy efficiency requirements in high density data centers. In this paper, a hybrid cooling system in data centers is investigated. In addition to traditional raised floor, cold aisle-hot aisle configuration, a liquid-air hybrid cooling system consisting of rear door heat exchangers attached to the back of racks is considered. The room is analyzed numerically using two CFD based simulation approaches for modeling rear door heat exchangers that are introduced in this study. The presented model is used in the second section of the paper to compare the hybrid cooling system with traditional air cooling systems. Several case studies are taken into account including the power increases in the racks and CRAC unit failure scenarios. A comparison is made between the hybrid cooling room and a purely air cooled room based on the rack inlet temperatures. Also in this study, total energy consumption by the cooling equipment in both air-cooled and hybrid data centers are modeled and compared with each other for different scenarios. The results show that under some circumstances the hybrid cooling could be an alternative to meet the ASHRAE recommended inlet air temperatures, while at the same time it reduces the cooling energy consumption in high density data centers.


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

2021 ◽  
Author(s):  
Ladan Vahidi-Arbabi

Thermal performance of complex buildings like data centers is not easy to evaluate. Experimental Investigation of the effects of energy conservation methods or any alteration that might occur in hundreds of variables in data centres would cost stakeholders time and money. And they might find worthless at times. Building energy model is a well-established field of science with an insufficient number of applications in data centers. This study presents methods of developing a data center model based on an actual case study. Moreover, it identifies effective calibrating strategies to increase the model performance accuracy relative to a recorded dataset. A reliable energy model can assist data center operators and researchers in different ways. As a result, calibrated energy model proved Earth Rangers’ data center can be independent of a heat pump or chiller use for most of the year, while ground heat exchangers deliver excessive heat to the ground as the heat sink.


2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Richard Eiland ◽  
John Edward Fernandes ◽  
Marianna Vallejo ◽  
Ashwin Siddarth ◽  
Dereje Agonafer ◽  
...  

Complete immersion of servers in dielectric mineral oil has recently become a promising technique for minimizing cooling energy consumption in data centers. However, a lack of sufficient published data and long-term documentation of oil immersion cooling performance make most data center operators hesitant to apply these approaches to their mission critical facilities. In this study, a single server was fully submerged horizontally in mineral oil. Experiments were conducted to observe the effects of varying the volumetric flow rate and oil inlet temperature on thermal performance and power consumption of the server. Specifically, temperature measurements of the central processing units (CPUs), motherboard (MB) components, and bulk fluid were recorded at steady-state conditions. These results provide an initial bounding envelope of environmental conditions suitable for an oil immersion data center. Comparing with results from baseline tests performed with traditional air cooling, the technology shows a 34.4% reduction in the thermal resistance of the system. Overall, the cooling loop was able to achieve partial power usage effectiveness (pPUECooling) values as low as 1.03. This server level study provides a preview of possible facility energy savings by utilizing high temperature, low flow rate oil for cooling. A discussion on additional opportunities for optimization of information technology (IT) hardware and implementation of oil cooling is also included.


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