Experimental Study on Thermal Environment and Stratified Air-Conditioning Load of Large-Space Building with Low-Sidewall Air Supply under Periodic Thermal Disturbance

2020 ◽  
pp. 553-562
Author(s):  
Chen Huang ◽  
Liang Qiao ◽  
Tianyu Bai ◽  
Haidong Wang ◽  
Zhijun Zou ◽  
...  
Keyword(s):  
Experimental Study ◽  
Air Conditioning ◽  
Thermal Environment ◽  
Large Space ◽  
Air Supply ◽  
Thermal Disturbance

Quantitative investigations on setting parameters of air conditioning (air-supply speed and temperature) in ventilated cooling rooms

2019 ◽  
Vol 30 (1) ◽  
pp. 99-113 ◽  
Author(s):  
Haofu Chen ◽  
Zhuangbo Feng ◽  
Shi-Jie Cao
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
Thermal Environment ◽  
Inertial Force ◽  
Index Formula ◽  
Design Parameters ◽  
Dimensionless Number ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort ◽  
Air Supply

Rational and scientific design of indoor air conditioning is essential. In the design of Heating, Ventilating and Air Conditioning system, air-supply speed (ventilation rate) and air-supply temperature are the two most important parameters. In the current study, numerical simulations and experimental measurements were adopted to investigate the influences of ventilation mode, air-supply velocity and air-supply temperature on indoor thermal comfort as well as building energy consumption in summer. Different ventilation modes (up supply and down exit, ceiling supply and ceiling exit) were considered in modelling. Based on the simulation and experimental results, dimensionless index [Formula: see text] is proposed, which represents the ratio of buoyancy weighting force to inertial force. This index can be used as a pre-evaluation index of indoor thermal comfort in preliminary design of air conditioning. It is an indicator to judge the working conditions in cooling-ventilated rooms. When [Formula: see text], the settlement and diffusion effects of indoor airflow reach a good level, which means that the parameter setting could provide a comfortable indoor thermal environment. The dimensionless number [Formula: see text] is a theoretically based tool in the pre-evaluation of indoor thermal environment, providing guidance for setting of ventilation design parameters.

Air-conditioning with underfloor air supply: Comfort in non-uniform thermal environment

1999 ◽  
Vol 20 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Y. Kawahara ◽  
K. Emura ◽  
M. Nabeshima ◽  
K. Bougaki ◽  
M. Kadoya
Keyword(s):  
Air Conditioning ◽  
Thermal Environment ◽  
Air Supply

scholarly journals Impact of Fan Airflow of IT Equipment on Thermal Environment and Energy Consumption of a Data Center

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6166
Author(s):  
Naoki Futawatari ◽  
Yosuke Udagawa ◽  
Taro Mori ◽  
Hirofumi Hayama
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Data Center ◽  
Air Conditioning ◽  
Thermal Environment ◽  
Operating Efficiency ◽  
Inlet Temperature ◽  
Total Energy Consumption ◽  
Air Supply ◽  
Machine Room

Energy-saving in regard to heating, ventilation, and air-conditioning (HVAC) in data centers is strongly required. Therefore, to improve the operating efficiency of the cooling equipment and extend the usage time of the economizer used for cooling information-technology equipment (ITE) in a data center, it is often the case that a high air-supply temperature within the range in which the ITE can be sufficiently cooled is selected. In the meantime, it is known that when the ambient temperature of the ITE rises, the speed of the built-in cooling fan increases. Acceleration of the built-in fan is thought to affect the cooling performance and energy consumption of the data center. Therefore, a method for predicting the temperature of a data center—which simply correlates supply-air temperature with ITE inlet temperature by utilizing existing indicators, such as air-segregation efficiency (ASE)—is proposed in this study. Moreover, a method for optimizing the total energy consumption of a data center is proposed. According to the prediction results obtained under the assumption of certain computer-room air-conditioning (CRAC) conditions, by lowering the ITE inlet temperature from 27 °C to 18 °C, the total energy consumption of the machine room is reduced by about 10%.

Model Experimental Study on Stratified Air Distribution with 2D-PIV for High Ceiling Industrial Plant

2011 ◽  
Vol 374-377 ◽  
pp. 610-617
Author(s):  
Jian Shen ◽  
An Gui Li ◽  
Yu Jiao Zhao
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Air Conditioning ◽  
Vertical Direction ◽  
Industrial Plant ◽  
Air Distribution ◽  
Air Supply ◽  
Stratification Effect ◽  
Experimental Findings ◽  
Real Scale

At present, the research ways of stratified air-conditioning technology mainly have two types, experimental study and numerical simulation. In this paper, a transparent Plexiglas model was designed, of which the size was supposed to be 1/50 of the real scale. PIV technology was innovatively applied into the experiment to measure the air distribution of an industrial plant. Different air supply velocities and different kinds of air supply outlets were taken into account to discuss the influence of them. Results revealed that as the jet velocity increased gradually, the airflow’s stratification effect became more evident. When the aspect ratio changed from 1:2 to 1:8, the diffusion degree in vertical direction increased obviously. In comparison with the rectangular air supply outlet, the circular one had lower decay, longer jet distance and better contractibility. The experimental findings are useful for optimizing the design of air distribution in high ceiling industrial plant.

Indoor Thermal Environment Research of Air Conditioning Office with Air from Window Gap

2013 ◽  
Vol 860-863 ◽  
pp. 1660-1665
Author(s):  
Ze Hua Liu ◽  
Yan Liao ◽  
Hao Ping Yu
Keyword(s):  
Numerical Simulation ◽  
Air Conditioning ◽  
Thermal Environment ◽  
Local Area ◽  
Indoor Thermal Environment ◽  
Air Infiltration ◽  
Air Supply ◽  
Field Velocity ◽  
Average Relative Humidity ◽  
Air Speed

The paper presents a numerical simulation study of indoor thermal environment of an air conditioning office in winter in Hengyang. Considering the effect of air infiltration from window gap, the distribution of indoor temperature field, velocity field and humidity field can be obtained when air supply angle is 45° down to the horizontal direction. Compared with simulation which air infiltration is ignored, the results show that average temperature of air conditioning area reduces 0.6 °C in Y = 1.1 m section. Air velocity is larger in Y = 1.1 m air conditioning zone. The air speed is greater than 0.2 m/s in local area, a sense blowing. Average relative humidity is larger in Y = 1.1 m air conditioning area. The research indicates that air infiltration can not be allowed to be neglected in numerical simulation.

Resistance Coefficient Research of the Train Air Supply Orifice

2012 ◽  
Vol 614-615 ◽  
pp. 475-479
Author(s):  
Hai Ying Wang ◽  
Chun Fang Li ◽  
Song Tao Hu ◽  
Lin Song
Keyword(s):  
Experimental Study ◽  
Temperature Field ◽  
Air Conditioning ◽  
High Speed ◽  
Plate Thickness ◽  
Resistance Coefficient ◽  
High Speed Train ◽  
Air Conditioning System ◽  
Air Supply ◽  
Air Conditioning Systems

High-speed train air-conditioning systems put forward higher request on the aspect of air uniformity and comfort. The use of orifice which can form a more uniform velocity and temperature field in the car can be widely applied to high-speed train air-conditioning system. The experimental study of the influence of several different factors (such as the opening rate, aperture, orifice plate thickness, etc.) in the research may provide a reference for the design choices of the orifice type.

A Study of Cooling Load Calculation of Stratified Air Conditioning System for Large Space Based on the Simultaneously Solving Model

2014 ◽  
Vol 672-674 ◽  
pp. 1755-1761 ◽  
Author(s):  
Ning Cai ◽  
Chen Huang
Keyword(s):  
Indoor Air ◽  
Air Conditioning ◽  
Thermal Environment ◽  
Cooling Capacity ◽  
Cooling Load ◽  
Large Space ◽  
Air Conditioning System ◽  
Load Calculation ◽  
Environment Experiment ◽  
Wall Surface Temperature

A calculation method for cooling load of stratified air conditioning system based on the simultaneously solving model is presented. Thermal environment experiment under summer condition is carried out in a large space building, indoor air temperature, inner wall surface temperature and cooling capacity were obtained; the stratified air conditioning cooling load calculated by the simultaneously solving model is compared with air conditioning cooling capacity in experiment, the relative error is 14%, taking the loss of cooling capacity and leakage loss, it can be thought that the simultaneously solving model can be used to calculate cooling load of stratified air conditioning system.

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