Numerical simulation of air distribution for monitoring the central air conditioning in large atrium

Author(s):  
Lixia Wang ◽  
Pawan Kumar ◽  
Mamookho Elizabeth Makhatha ◽  
Vishal Jagota
2011 ◽  
Vol 374-377 ◽  
pp. 610-617
Author(s):  
Jian Shen ◽  
An Gui Li ◽  
Yu Jiao Zhao

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.


2011 ◽  
Vol 250-253 ◽  
pp. 3107-3114
Author(s):  
Hong Ming Fan ◽  
Kai Yuan He ◽  
Zhi Fang Yin ◽  
Dan Zhang

The typical subway island-platform of Beijing as research object was present in the article. Taking two-equation turbulence model and giving boundary conditions of piston wind and train heat load change with the time, adopting numerical method simulates air distribution of air-conditioning and ventilation system in subway. The results indicate that piston wind effect has significant impact on the area of platform entrance and staircase entrance while station with safety doors can obstruct piston effect at a certain degree. Simultaneity, the supply- exhaust air system offers relatively uniform temperature and velocity field, which meets requirements of transitory comfort for passengers. It is found that numerical simulation method can simulate and forecast air distribution of air conditioning and ventilating system in subway station. In conclusion, it can provide the reference for optimizing air-conditioning and ventilation system, improving thermal environment designing of subway station.


Author(s):  
Wei Bing ◽  
Li Li ◽  
Jiang Lu ◽  
Zhang Wei

At present all cold air distribution systems are being used widely due to their advantages of smaller ductwork, shorter floor-to-floor height and less energy consumption etc. They are mostly used in VAV (Variable Air Volume) systems or with the radiant panel systems in the office and residential buildings at the supply air dew point temperature of 6∼10°C, rarely used in large space buildings. The technology of stratified air conditioning is one of the energy saving technologies to large space buildings, which has been popularly used in the conventional air supply systems with the supply air dew point temperature of 11∼16°C. In this paper, the cold air distribution system and the stratified air conditioning technology in a large space building are combined to study. With the method of CFD, the indoor thermal environment of a large space workshop is simulated. The velocity and the temperature as well as the relative humidity fields under different air flow modes are presented, analyzed and compared. With the help of numerical simulation results, the optimal airflow mode is proposed, which show that the all cold air distribution with the stratified air conditioning is a good option for large space buildings. All these above will be good references to the application of cold air distribution system and the selection of the airflow mode in large space buildings.


2021 ◽  
Vol 7 ◽  
pp. 4035-4046
Author(s):  
Wenqiang Jing ◽  
Junqi Yu ◽  
Wei Luo ◽  
Chujun Li ◽  
XinYi Liu

Author(s):  
Amanda J. Wheeler ◽  
Ryan W. Allen ◽  
Kerryn Lawrence ◽  
Christopher T. Roulston ◽  
Jennifer Powell ◽  
...  

During extreme air pollution events, such as bushfires, public health agencies often recommend that vulnerable individuals visit a nearby public building with central air conditioning to reduce their exposure to smoke. However, there is limited evidence that these “cleaner indoor air shelters” reduce exposure or health risks. We quantified the impact of a “cleaner indoor air shelter” in a public library in Port Macquarie, NSW, Australia when concentrations of fine particulate matter (PM2.5) were elevated during a local peat fire and nearby bushfires. Specifically, we evaluated the air quality improvements with central air conditioning only and with the use of portable high efficiency particulate air (HEPA) filter air cleaners. We measured PM2.5 from August 2019 until February 2020 by deploying pairs of low-cost PM2.5 sensors (i) inside the main library, (ii) in a smaller media room inside the library, (iii) outside the library, and (iv) co-located with regulatory monitors located in the town. We operated two HEPA cleaners in the media room from August until October 2019. We quantified the infiltration efficiency of outdoor PM2.5 concentrations, defined as the fraction of the outdoor PM2.5 concentration that penetrates indoors and remains suspended, as well as the additional effect of HEPA cleaners on PM2.5 concentrations. The infiltration efficiency of outdoor PM2.5 into the air-conditioned main library was 30%, meaning that compared to the PM2.5 concentration outdoors, the concentrations of outdoor-generated PM2.5 indoors were reduced by 70%. In the media room, when the HEPA cleaners were operating, PM2.5 concentrations were reduced further with a PM2.5 infiltration efficiency of 17%. A carefully selected air-conditioned public building could be used as a cleaner indoor air shelter during episodes of elevated smoke emissions. Further improvements in indoor air quality within the building can be achieved by operating appropriately sized HEPA cleaners.


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