Application and Analysis Chilling Ceiling Combined with Displacement Ventilation System in Office Buildings

2010 ◽  
Vol 160-162 ◽  
pp. 294-300
Author(s):  
Ling Wang ◽  
Wei Yang Qi ◽  
Ri Chao Liu ◽  
Shun Jun He
Keyword(s):  
Indoor Air ◽  
Thermal Stratification ◽  
Ventilation System ◽  
Displacement Ventilation ◽  
Airflow Velocity ◽  
Indoor Airflow ◽  
Air Supply ◽  
Computational Fluid Dynamics Cfd ◽  
Save Energy ◽  
Lower Temperature

Using the method of computational fluid dynamics (CFD), numerically simulates office building with chilling ceiling /displacement ventilation (CC/DV) and analyzes indoor airflow velocity field, temperature field and thermal stratification height of the building. Consider that the CC/DV system can improve indoor air quality and save energy. And the CC/DV system could solve many constraints of displacement ventilation system. when the cooling load is large, due to the limit of air supply and temperature supply the displacement ventilation system can not be used, but the CC/DV system could well satisfied the requirement of body. The CC/DV system also has the problem of lower thermal stratification height because the chilling ceiling has a lower temperature.

CFD Investigation for Indoor Environment of a District Standard Room in Jinan City

2014 ◽  
Vol 548-549 ◽  
pp. 1706-1711
Author(s):  
Dong Yang ◽  
Qing Mei Wen ◽  
Cong Ju Zhang ◽  
Xue Ting Liu ◽  
Shi Jun Wei
Keyword(s):  
Composite System ◽  
Ventilation System ◽  
Simulation Method ◽  
Displacement Ventilation ◽  
Air Velocity ◽  
Vertical Temperature ◽  
Airflow Velocity ◽  
Indoor Airflow ◽  
Radiant Cooling ◽  
Air Speed

This paper introduces the principle and characteristics of roof radiant cooling and displacement ventilation system, using numerical simulation method, the indoor airflow velocity and temperature field of the typical bedroom which uses the composite system in Ji'nan City under the different supply air velocity was calculated. The experimental results show that when the air temperature is 295.15K, to keep the indoor vertical temperature less than 3 °C, air speed should be greater than 0.1m/s and less than or equal to 0.3m/s, to provide reference for the application of roof radiant cooling and displacement ventilation system.

Computational Modeling of Particulate Pollutant Transport in a Ventilated Room in the Presence of Two Heated Breathing and Rotating Manikins

2017 ◽  
Author(s):  
Seyed Ali Keshavarz ◽  
Mazyar Salmanzadeh ◽  
Goodarz Ahmadi
Keyword(s):  
Air Quality ◽  
Computational Modeling ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Rotational Motion ◽  
Indoor Environment ◽  
Ventilation System ◽  
Thermal Plume ◽  
Displacement Ventilation ◽  
Simulation Results

Recently, attention has been given to indoor air quality due to its serious health concerns. Clearly the dispersion of pollutant is directly affected by the airflow patterns. The airflow in indoor environment is the results of a combination of several factors. In the present study, the effects of thermal plume and respiration on the indoor air quality in a ventilated cubicle were investigated using an unsteady computational modeling approach. The person-to-person contaminant transports in a ventilated room with mixing and displacement ventilation systems were studied. The effects of rotational motion of the heated manikins were also analyzed. Simulation results showed that in the cases which rotational motion was included, the human thermal plume and associated particle transport were significantly distorted. The distortion was more noticeable for the displacement ventilation system. Also it was found that the displacement ventilation system lowered the risk of person-to-person transmission in an office space in comparison with the mixing ventilation system. On the other hand the mixing system was shown to be more effective compared to the displacement ventilation in removing the particles and pollutant that entered the room through the inlet air diffuser.

Modeling the Applicability of a Displacement Ventilation System

2021 ◽  
Vol 11 (1) ◽  
pp. 63-89
Author(s):  
Edgar C. Ambos ◽  
Evan Neil V. Ambos ◽  
Lanndon A. Ocampo
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Heat Load ◽  
Ventilation System ◽  
Internal Heat ◽  
The Philippines ◽  
Airflow Rate ◽  
Displacement Ventilation ◽  
Tropical Country

Due to its significant role in improving indoor air quality, displacement ventilation system is widely adopted in current literature. This paper proposes a displacement ventilation system for room conditions with ceilings that are relatively low, internal heat load could be high, walls could be sunlit, and occupants doing the low physical activity. These conditions are prevalent in the Philippines, being a tropical country. Input parameters to the design process such as heat load, the height of the ceiling, comfort, and indoor air quality requirements were generated, and the main output parameters are the stratification height and ventilation airflow rate. To demonstrate the proposed displacement ventilation system, four cases were generated. Results show that the ventilation airflow rates obtained from the four cases were greater than the minimum outdoor air requirements for health in conference rooms and large assembly areas which are 17.5 and 3.5 liters/sec*person respectively, for smoking and no smoking rooms.

scholarly journals Designing Jet Fan Ventilation for an Underground Car Park by CFD Simulations

2018 ◽  
Vol 63 (1) ◽  
pp. 39-43 ◽  
Author(s):  
Miroslava Kmecová ◽  
Michal Krajčík ◽  
Zuzana Straková
Keyword(s):  
Exchange Rate ◽  
High Efficiency ◽  
Ventilation System ◽  
Cfd Simulations ◽  
Air Exchange Rate ◽  
Air Supply ◽  
Car Park ◽  
Computational Fluid Dynamics Cfd ◽  
Alternative Designs ◽  
Air Exchange

The aim of this study was to design a fire ventilation system with impulse jet fans for an underground car park. With respect to the number of parameters affecting the spread of smoke that need to be considered, there is a good chance of miscalculations if only conventional plain calculations are used in the design process. To avoid mistakes, visualize the fluid flow, and to compare the design variants it is practical to use computational fluid dynamics (CFD). In this study, CFD simulations were used to compare alternative designs of a fire ventilation system. In one alternative the exhaust shafts were located in both parts of the car park and the jet fans were directed to the corresponding shafts. The air exchange rate was 10-times per hour. In another alternative both exhaust shafts were located on one side opposite to the main air supply, and the air exchange rate was 15-times per hour. The results showed preference of the second alternative, when the smoke was completely exhausted and the visibility improved substantially, whereas in the first alternative the car park was not sufficiently ventilated even 600 seconds after the fire had been put out. The results emphasize that proper location of elements of the ventilation system is crucial to attain high efficiency of fire ventilation.

Experimental and Simulation Validation Methods of Local Exhaust Ventilation (LEV) in Training Facilities Building

2013 ◽  
Vol 315 ◽  
pp. 997-1001 ◽  
Author(s):  
Ng Chee Seng ◽  
Abdul Mutalib Leman ◽  
Azmahani Sadikin
Keyword(s):  
Indoor Air ◽  
Ventilation System ◽  
Percentage Error ◽  
Local Exhaust Ventilation ◽  
Geometry Model ◽  
Exhaust Ventilation ◽  
Simulation Validation ◽  
Air Ventilation ◽  
Computational Fluid Dynamics Cfd ◽  
Real Flow

LEV is a ventilation system that collects and sucks out particles such as dusts, mists, gases, vapors or fumes out of work station, so that they can’t be breathed in by occupants. There is a lot of LEV allocated and installed in order to help protecting occupants’ health but it doesn’t work properly. To overcome this issue, computational fluid dynamics (CFD) will be implemented. Past studies CFD techniques represent a very significant improvement of air ventilation systems. However, CFD is just a tool in prediction model, which can lead to inaccuracy of predicting airflow due to problems with pre-processing, solver and post-processing with parameter from actual experimental results. As of yet, it is not possible to 100% accurately simulate airflow around a body. These codes are simply models which are close to that of a real flow, but not an exact match. All of these require validation to help minimizing percentage error in CFD methodology. Several strategies are needed to boost effectiveness of LEV in terms of predicting airflow in a geometry model. The outcome of this research can be used as a benchmark or guideline for industries to help improving indoor air quality (IAQ).

The Analysis of Comfortable and Energy Saving of Ice-Storage Low Temperature Air Supply System

2014 ◽  
Vol 960-961 ◽  
pp. 635-638
Author(s):  
Li Bai ◽  
Xue Zhi Zhou ◽  
Yan Wang ◽  
Ya Wei Hua
Keyword(s):  
Low Temperature ◽  
Energy Saving ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Integrated Approach ◽  
Supply System ◽  
Energy Resources ◽  
Ice Storage ◽  
Air Supply ◽  
Save Energy

More and more attentions have been paid on ice-storage low temperature air supply system because of its notable energy saving effects and comfort. The paper expatiate on that ice-storage low temperature air supply system brings a series of especial superiority to modern air-condition cause. The results show that low temperature air supply system can exert the potential advantage of ice-storage further. The combination of ice-storage and low temperature air supply system can obtain an “integrated approach”, which can save energy resources and improve human body comfort and indoor air quality.

A Study on the Evaluation of Ventilation Performance According to the Location of the Return Diffusers of an Upward Displacement Ventilation System in a Dome-Shaped Small Concert Hall

2019 ◽  
Vol 27 (03) ◽  
pp. 1950028
Author(s):  
Yong-Il Kwon
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Vertical Wall ◽  
High Energy ◽  
Displacement Ventilation ◽  
Concert Hall ◽  
Upward Displacement ◽  
Ventilation Performance

The modern people are active in various cultural facilities and enjoy the leisure life. The spectators and performers using a small concert hall generally use this space for about 2[Formula: see text]h in an enclosed state, and so the space should maintain a comfortable thermal environment and indoor air quality. The ventilation systems that can be applied to small concert hall are generally classified as the mixing ventilation system and the displacement ventilation system, but the upward displacement ventilation system is known to be able to maintain the clean indoor air quality with high energy efficiency. The upward displacement ventilation system installed in a dome-shaped small concert hall is not limited in the height of the vertical wall. Therefore, it is necessary to evaluate the optimal height of the return diffuser by utilizing the ventilation performance and the air diffusion performance index (ADPI). This study was carried out to evaluate the effect of the return diffuser position on the ventilation performance of an upward displacement ventilation system installed in a dome-shaped small concert hall. It was confirmed that as the height at which the return diffuser is installed on the vertical wall increases, the ventilation efficiency increases and the thermal stratification formed in the upper area is significantly reduced.

Study on the Pollutant Control of Industrial Buildings with Mechanical Ventilation

2011 ◽  
Vol 243-249 ◽  
pp. 4949-4955
Author(s):  
Yi Wang ◽  
Yan Qiu Huang ◽  
Zhi Peng Li ◽  
Le Wang ◽  
Jie Gao
Keyword(s):  
Ventilation System ◽  
Pollution Source ◽  
Average Concentration ◽  
Space Distribution ◽  
Industrial Building ◽  
Displacement Ventilation ◽  
Pollutant Concentrations ◽  
Industrial Buildings ◽  
Pollutant Source ◽  
Computational Fluid Dynamics Cfd

The aim of this paper is to study the control effects of pollutants with different ventilation methods in industrial buildings. Comparative researches are conducted between the push-pull ventilation system and displacement ventilation system. Formaldehyde (HCHO) is selected as the main pollutant in the industrial buildings in this paper. The computational fluid dynamics (CFD) is used to analysis the space distribution of pollutant concentrations with the pollution sources at different locations. Through comparative study，the pollutants distribution with the same supply air volume and pollutants diffusion intensity are evaluated from the following two aspects. Firstly, when the height of the pollutant source is 1.2 m in the industrial building, the average concentration of the contaminant at the space section with push-pull ventilation system is relatively higher than that with displacement ventilation system. Secondly, the average concentration with push-pull ventilation system is 0.00058 kmol/m3 while displacement ventilation system is 0.00097 kmol/m3 when the height of the pollutant source is 0.6 m. And when it is 0.3 m, they are 0.00016 kmol/m3 and 0.0017 kmol/m3 respectively. Thus, the concentration of the contaminant in displacement ventilation is higher than the push-pull ventilation’s with the location of the pollution source continuously declining in the height direction.

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