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.

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.

scholarly journals An OpenFOAM simulation of the natural ventilation system in a university chemical laboratory

2020 ◽  
Vol 167 ◽  
pp. 04003
Author(s):  
M Córdova-Suárez ◽  
O. Tene-Salazar ◽  
F. Tigre-Ortega ◽  
S. Carrillo-Ríos ◽  
D. Córdova-Suárez ◽  
...  
Keyword(s):  
Working Conditions ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Operating Conditions ◽  
Climate Data ◽  
Chemical Laboratory ◽  
Indoor Airflow ◽  
Air Intake ◽  
Air Speed ◽  
Closed Environment

The indoor airflow with a natural ventilation system was numerically calculated using the laminar and turbulent approach. In the chemical laboratory of the Technical University of Ambato, the computational code OpenFoam demonstrated an ability to numerically predict flow patterns. The design contemplated the natural ventilation system considering the laboratories’ working conditions not only in summer, but also in a winter week. These two operating conditions are calculated on a fully open and closed environment. For a room with a capacity of 20 people, the climate data average values were recorded at 14.0 ° C, 81.7%, 1.7 m /s for temperature, relative humidity, and wind speed, respectively. Furthermore, the demonstration has shown that the homogeneous occupancy air speed average is was 0.7 m / s with a facade air intake of 1.0 m / s 0.6 m / s in the room valid for the exchange of air and evacuation of pollutants. The maximum pressures were found in the lower part of the laboratory. This prevents the modification of the thermo-hygrometric conditions.

An Experimental Research on Wall Radiant Cooling and Wall-Attached-Jet Air-Conditioning System

2014 ◽  
Vol 501-504 ◽  
pp. 2244-2251 ◽  
Author(s):  
Xiang Lei Kong ◽  
Xin Li Zi ◽  
Long Yun ◽  
Xiao Song Zhang
Keyword(s):  
Indoor Air ◽  
Air Conditioning ◽  
Stable Operation ◽  
Displacement Ventilation ◽  
Vertical Temperature ◽  
Vertical Temperature Profile ◽  
Air Conditioning System ◽  
Radiant Cooling ◽  
Operation Period ◽  
The Subject

Taking the radiant cooling combined with wall-attached-jet air-conditioning system as the subject in a laboratory of Jiangsu university, an experimental study was carried out on pre-dehumidifying period, stable operation period and system shutdown period, along with analysis. The objective is to analyze the pre-dehumidification of the system, indoor air temperature and humidification change, vertical temperature profile and condensation sensitivity. The results show that the hybrid air-conditioning can provide high thermal comfort and avoid condensation effectively, which shows the better performance compared to the system of radiant cooling combined with displacement ventilation to some extent.

scholarly journals The Airflow Reversal Law in Ventilation System after Coal and Gas Outburst in Tunneling Roadway

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Junhong Si ◽  
Yiqiao Wang ◽  
Genyin Cheng ◽  
Lin Li ◽  
Yitian Shao ◽  
...  
Keyword(s):  
Ventilation System ◽  
Simulation Method ◽  
Coal And Gas Outburst ◽  
Air Velocity ◽  
Relative Variation ◽  
Gas Concentration ◽  
Gas Outburst ◽  
Cubic Polynomial ◽  
The Relationship ◽  
Topology Graph

Considering the coal and gas outburst phenomenon in the mining space, this paper analyzes the main characteristics of coal and gas outburst accidents, defines the outburst airflow reversal degree, and constructs a simplified topology graph of tunneling ventilation system, while the air door is not destroyed. Using the numerical simulation method, this paper elaborates on the relationship between the outburst pressure and airflow reversal degree. The results indicate that the inlet pressure increases to 264 hPa and the outlet pressure increases to 289 hPa when the outburst pressure increases from 1 hPa to 1 MPa, and the relative variation coefficient of pressure decreases from 1501.5 to 1.62 in the inlet of return airway and decreases from 2002 to 1.65 in the outlet of return airway. Furthermore, the air velocity decreases from −1.38 to −284.44 m/s in the inlet and increases from 3.10 to 297.38 m/s in the outlet. Moreover, the gas concentration of the inlet and outlet in return airway increases rapidly with the increase of outburst pressure. When the outburst pressure is greater than 0.15 MPa, the gas concentration will be over 98% in tunneling ventilation system. This paper also finds out a cubic polynomial relationship existing between the reversal degree and the outburst pressure. It provides the prediction of coal and gas outburst and serves as a guidance in case mine ventilation disturbances occur.

Control of temperature and fume generation by cooking in a residential kitchen by ceiling radiative cooling and fume hood extraction

2020 ◽  
pp. 1420326X2094575
Author(s):  
Wang Li ◽  
Hanqing Wang ◽  
Chengjun Li ◽  
Chuck Wah Yu
Keyword(s):  
Waste Heat ◽  
Heat Radiation ◽  
Living Room ◽  
Fume Hood ◽  
Airflow Velocity ◽  
Pollution Dispersion ◽  
Indoor Airflow ◽  
Healthy Environment ◽  
Radiant Cooling ◽  
Chinese Standard

The heat radiation in a residential kitchen was simulated by CFD (Computational-fluid-dynamics) to evaluate the cooling by a radiant cooling ceiling panel and pollution dispersion by the range hood and the air extraction system. The kitchen has a 2-hobs stove and a fume hood for removing waste heat and fumes. The simulation was validated by measurements in a domestic kitchen in a home in Changsha, China, where summer temperature is generally about 33 °C and often over 35–42°C. The simulation results show that the pollutant concentration in the kitchen during cooking was much lower than the Chinese standard criteria of GB/T18883-2002. A standard turbulence model was used, which indicated satisfactory distribution of temperature and airflow in the kitchen. The indoor airflow velocity was low. The airflow temperature when both hobs were used was slightly higher by 3–4°C than when a single hob was used. The temperature in the kitchen during cooking was about 28 °C, which was a degree lower than the living-room temperature, thus maintaining a comfortable thermal and healthy environment. The radiant cooling in the ceiling was shown to be a significant contributing factor. The ring suction type range hood has a sufficient capacity to remove the kitchen fume contaminants.

scholarly journals Analysis of Thermal Comfort in an Office Space Using Two Typical Ventilation Modes.

2018 ◽  
Vol 3 (8) ◽  
pp. 35
Author(s):  
Chinedum Vincent Okafor ◽  
Kevin Chuks Okolie ◽  
Peter Ogunoh ◽  
Udeagwu Hyginus Oguike
Keyword(s):  
Air Conditioning ◽  
Ventilation System ◽  
Office Building ◽  
Vertical Temperature Gradient ◽  
Displacement Ventilation ◽  
Vertical Temperature ◽  
System A ◽  
Office Space ◽  
Ceiling Height ◽  
Ventilation Modes

This study carried out a comparative study to evaluate the air-conditioning performance of an office space under two typical ventilation modes (displacement and mixing ventilation system). A wall supply diffuser is located at the ceiling height for the mixing ventilation case, whereas, the supply diffuser is at the floor level for the displacement ventilation case. In both cases, the exhaust grill is located at the ceiling. From the result of the simulation, the researchers observed that the displacement ventilation system could have a higher risk of discomfort relating to vertical temperature gradient than when compared to the mixing ventilation case. More so, the simulation result indicates that the temperature distribution in an office building is a function of the type of ventilation system adopted and marginally affected by the diffuser arrangement.

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