Analyzing the Cooling Efficiency of the Thermal Environment in Data Centers

2014 ◽  
Vol 6 (4) ◽  
pp. 15-27
Author(s):  
Yongmei Xu ◽  
Jingru Zhang ◽  
Yuhui Deng ◽  
Lan Du ◽  
Rong Jiao
Keyword(s):  
Energy Efficiency ◽  
Air Temperature ◽  
Thermal Load ◽  
Air Conditioning ◽  
High Speed ◽  
Data Centers ◽  
Thermal Environment ◽  
External Environment ◽  
Cooling Systems ◽  
Standard Data

Given the explosive growth of data, scalability and fault tolerance have become a fundamental challenge for data center network structures. Temperature in data centers significantly affects the failure ratio of high-speed network devices. Various types of air distribution schemes influence the temperature of network equipment differently, and the cooling cost in data centers dominates the overall energy cost. On the basis of the energy efficiency of cooling systems, this study analyzes and compares the thermal load distribution in the enclosure of standard and non-standard data centers by considering the effects of the external environment. Analysis results demonstrate that the external environment significantly affects the thermal load of non-standard data centers. By leveraging on the air temperature outside data centers and on the inlet/outlet of IT equipment, the air temperature and return air temperature of air conditioning are calculated when performing hot and cold aisle containment. The calculations indicate that sealing an appropriate aisle (hot or cold aisle) can significantly reduce the energy consumption of cooling systems in terms of the external air temperature outside data centers. Furthermore, if the air temperature outside data centers is higher than the temperature at the inlet of IT equipment, sealing the cold aisle outperforms sealing the hot aisle. By contrast, the aisle to be sealed depends on the energy efficiency ratio of the air conditioning.

scholarly journals The Numerical Simulation of the Airflow Distribution and Energy Efficiency in Data Centers with Three Types of Aisle Layout

2019 ◽  
Vol 11 (18) ◽  
pp. 4937 ◽  
Author(s):  
Jing Ni ◽  
Bowen Jin ◽  
Shanglei Ning ◽  
Xiaowei Wang
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Air Conditioning ◽  
Data Centers ◽  
Simulation Method ◽  
Cooling Capacity ◽  
Energy Utilization ◽  
Improve Energy Efficiency ◽  
Electricity Cost ◽  
Airflow Distribution

The energy consumption of fast-growing data centers is drawing attentions from not only energy organizations and institutions all over the world, but also charity groups, such as Greenpeace, and research shows that the power consumption of air conditioning makes up a large proportion of the electricity cost in data centers. Therefore, more detailed investigations of air conditioning power consumption are warranted. Three types of airflow distributions with different aisle layouts (the open aisle, the closed cold aisle, and the closed hot aisle) were investigated with Computational Fluid Dynamics (CFD) methods in a typical data center of four rows of racks in this study. To evaluate the results of thermal and bypass phenomenon, the temperature increase index (β) and the energy utilization index (ηr) were used. The simulations show that there is a better trend of the β index and ηr index both closed cold aisle and closed hot aisle compared with free open aisle. Especially with high air flow rate, the β index decreases and the ηr index increases considerably. Moreover, the results prove the closed aisles (both closed cold aisle and closed hot aisle) can not only significantly improve the airflow distribution, but also reduce the mixture of cold and heat flow, and therefore improve energy efficiency. In addition, it proves the design of the closed aisles can meet the increasing density of installations and our simulation method could evaluate the cooling capacity easily.

Climatic Strategies of Indoor Thermal Environment for Residential Buildings in Yangtze River Region, China

2011 ◽  
Vol 20 (1) ◽  
pp. 101-111 ◽  
Author(s):  
Baizhan Li ◽  
Wei Yu ◽  
Meng Liu ◽  
Nan Li
Keyword(s):  
Energy Efficiency ◽  
Thermal Comfort ◽  
Yangtze River ◽  
Air Conditioning ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Residential Buildings ◽  
Design Strategies ◽  
River Region ◽  
Climatic Adaptability

Yangtze River Valley is situated within the Hot Summer and Cold Winter zone, and residents in this region of China would require HVAC system to alleviate thermal comfort conditions, although this is tempered by the Design Code (DBJ50-071-2007) for energy efficiency. A 1-year survey of about 200 residential homes was carried out in eight cities covering the breadth of the region. The acceptable temperature range for the residents in this area was 16.3—28.1°C and the thermal neutral temperature was found to be 27.6°C in summers and 17.5°C in winters. People in different area can vary in their adaptability and comfortableness. Therefore, there is a need to investigate the national comfort parameter introduced in the Code for Design of Heating and Ventilation and Air Conditioning (GB50019-2003). The results found that if air-conditioning system was set to 27.5°C instead of 26°C as required by GBJ19-87: Design Standard of Heating and Ventilation and Air Conditioning, a 16.5% saving of energy consumption could be achieved. The findings demonstrated the role of natural ventilation in the expansion of the thermal comfort zone for the residents, especially during the summer seasons. A climatic adaptability model has been established by this study to contribute to the passive climatic design strategies for a better economic and energy efficiency of buildings.

scholarly journals Performance of Air Conditioning Unit under Constant Outdoor Wet-Bulb Temperature and Varied Dry-Bulb Temperature

2021 ◽  
Vol 39 (5) ◽  
pp. 1483-1490
Author(s):  
Andriyanto Setyawan ◽  
Susilawati Susilawati ◽  
Tandi Sutandi ◽  
Hafid Najmudin
Keyword(s):  
Energy Efficiency ◽  
Air Temperature ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Air Conditioner ◽  
Outdoor Air ◽  
Efficiency Ratio ◽  
Liquid Line ◽  
Discharge Temperature ◽  
Line Temperature

An experiment has been carried out for examining the performance of an air conditioning unit under constant outdoor wet-bulb temperature and varied dry-bulb temperature. During the experiment, the wet-bulb temperature of the compartment for outdoor unit was maintained at 22℃ and the dry-bulb temperature was varied from 24℃ to 36℃. The increase of outdoor air temperature results in the increase of supply air temperature, discharge temperature, suction temperature, and liquid line temperature. These cause the degradation of the air conditioner performance. An increase of power consumption by 1.4% and decrease of cooling capacity by 0.8% were observed for each 1℃ increase of outdoor air temperature. As a result, the energy efficiency ratio drops by 2% for each 1℃ increase of outdoor air temperature.

Thermal Environment Analysis and Improvement on Isolated Cold Aisle Data Centers

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Lin Su ◽  
Zhilin Huang ◽  
Kaijun Dong
Keyword(s):  
Air Temperature ◽  
Data Centers ◽  
Thermal Environment ◽  
High Porosity ◽  
Temperature Uniformity ◽  
Transitional Form ◽  
Environment Analysis ◽  
Cooling Performance ◽  
Adequate Ventilation ◽  
Airflow Distribution

Abstract Isolated cold aisle airflow distribution is a transitional form from non-isolated airflow distribution to closed cold aisle airflow distribution. With the increase of the power of racks, cooling failure may happen in the layout of the isolated cold aisle. This paper presents the study on cooling performance of the racks which are improved through bottom ventilating reform and adjustment. Inlet/outlet air temperature and mass flow rate of the racks are investigated in detail under conditions of various bottom ventilated areas and various porosities of the raised floor. The characteristics of airflow distribution are contrastively analyzed through calculating indexes of the thermal environment of data centers. Results show that adequate ventilation through the bottom of the racks is good for improvement of the state of airflow distribution. There is an optimization range (0.1–0.3 m and 0.05–0.15 m, respectively) of the ventilated area at the bottom of the racks. And high porosity (above 50%) of the ventilated area can reduce the inlet and outlet temperatures of the racks and the racks in different positions have a better temperature uniformity. In conclusion, bottom ventilation of racks is a feasible plan to improve airflow distribution, and schemes of ventilated area and porosity of corresponding raised floor should be designed respectively under consideration of the layout of racks and AC.

Energy-Efficiency Through the Integration of Information and Communications Technology Management and Facilities Controls

2009 ◽  
Author(s):  
Michael K. Patterson ◽  
Michael Meakins ◽  
Dennis Nasont ◽  
Prasad Pusuluri ◽  
William Tschudi ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Air Temperature ◽  
Data Center ◽  
Temperature Sensor ◽  
Data Centers ◽  
Cooling System ◽  
Information And Communications Technology ◽  
Demonstration Project ◽  
Communications Technology ◽  
Control Loop

Increasing energy-efficient performance built into today’s servers has created significant opportunities for expanded Information and Communications Technology (ICT) capabilities. Unfortunately the power densities of these systems now challenge the data center cooling systems and have outpaced the ability of many data centers to support them. One of the persistent problems yet to be overcome in the data center space has been the separate worlds of the ICT and Facilities design and operations. This paper covers the implementation of a demonstration project where the integration of these two management systems can be used to gain significant energy savings while improving the operations staff’s visibility to the full data center; both ICT and facilities. The majority of servers have a host of platform information available to the ICT management network. This demonstration project takes the front panel temperature sensor data from the servers and provides that information over to the facilities management system to control the cooling system in the data center. The majority of data centers still use the cooling system return air temperature as the primary control variable to adjust supply air temperature, significantly limiting energy efficiency. Current best practices use a cold aisle temperature sensor to drive the cooling system. But even in this case the sensor is still only a proxy for what really matters; the inlet temperature to the servers. The paper presents a novel control scheme in which the control of the cooling system is split into two control loops to maximize efficiency. The first control loop is the cooling fluid which is driven by the temperature from the physically lower server to ensure the correct supply air temperature. The second control loop is the airflow in the cooling system. A variable speed drive is controlled by a differential temperature from the lower server to the server at the top of the rack. Controlling to this differential temperature will minimize the amount of air moved (and energy to do so) while ensuring no recirculation from the hot aisle. Controlling both of these facilities parameters by the server’s data will allow optimization of the energy used in the cooling system. Challenges with the integration of the ICT management data with the facilities control system are discussed. It is expected that this will be the most fruitful area in improving data center efficiency over the next several years.

scholarly journals Improvement of Energy Efficiency and Control Performance of Cooling System Fan Applied to Industry 4.0 Data Center

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 582 ◽  
Author(s):  
Jae-Sub Ko ◽  
Jun-Ho Huh ◽  
Jong-Chan Kim
Keyword(s):  
Energy Efficiency ◽  
Industry 4.0 ◽  
Data Centers ◽  
Fuzzy Controller ◽  
Cooling System ◽  
Pi Controller ◽  
Control Performance ◽  
Cooling Systems ◽  
Proportional Integral ◽  
And Performance

This paper proposes a control method to improve the energy efficiency and performance of cooling fans used for cooling. In Industry 4.0, a large number of digital data are used, and a large number of data centers are created to handle these data. These data centers consist of information technology (IT) equipment, power systems, and cooling systems. The cooling system is essential to prevent failure and malfunction of the IT equipment, which consumes a considerable amount of energy. This paper proposes a method to reduce the energy used in such cooling systems and to improve the temperature control performance. This paper proposes an fuzzy proportional integral(FPI) controller that controls the input value of the proportional integral(PI) controller by the fuzzy controller according to the operation state, a VFPI (Variable Fuzzy Proportional Integral) controller that adjusts the gain value of the fuzzy controller, and a variable fuzzy proportion integration-variable limit (VFPI-VL) controller that adjusts the limit value of the fuzzy controller’s output value. These controllers control the fan applied to the cooling system and compare the energy consumed and temperature control performance. When the PI controller consumes 100% of the power consumed, the FPI is 50.5%, the VFPI controller is 44.3%, and the VFPI-VL is 32.6%. The power consumption is greatly reduced. In addition, the VFPI-VL controller is the lowest in temperature variation, which improves the energy efficiency and performance of the cooling system using a fan. The methods presented in this paper can not only be applied to fans for cooling, but also to variable speed systems for various purposes and improvement of performance and efficiency can be expected.

Supply Chain Optimization Audit (SCOA) for Green ICT Opportunities

2011 ◽  
pp. 559-580 ◽  
Author(s):  
Saugato Mukerji ◽  
Aditya K. Ghose
Keyword(s):  
Energy Efficiency ◽  
Supply Chain ◽  
Supply Chains ◽  
Energy Saving ◽  
Air Conditioning ◽  
Data Centers ◽  
Supply Chain Optimization ◽  
Green Ict

Green ICT is a lot more than efficient air-conditioning of data centers and switching off monitors and desktop PCs. ICT has the ability to give rise to and continuously enable energy saving on a scale 50 to 100 times bigger by becoming the technology that detects and prevents process inefficiency of energy intensive supply chains. Energy efficiency that can only be sustainably achieved as a result of using ICT creatively is outlined in this chapter. The authors consider the optimization of supply chain as a crucial enabler of the overall effort of an organization to improve its environmental credentials. Therefore, undertaking the audits of an organization’s supply chains, and ensuring that the end result improves its efficiency is one way of limiting the carbon generated during its activities.

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