Natural Ventilation in Workshop with Different Horizontal Arrangement of Heat Source

2012 ◽  
Vol 229-231 ◽  
pp. 2411-2414
Author(s):  
Ya Xin Su ◽  
Xin Wan
Keyword(s):  
Temperature Distribution ◽  
Heat Source ◽  
Natural Ventilation ◽  
Air Flow ◽  
Ventilation Rate ◽  
Pollutant Emission ◽  
Distribution Factor ◽  
Cfd Method ◽  
The Right ◽  
Horizontal Arrangement

The natural ventilation in a heating workshop with different horizontal arrangement of heat source was numerically simulated based on computational fluid dynamics (CFD) method. Realizable k- turbulent model was used to calculate the air flow and temperature distribution. Simulation results showed that the horizontal arrangement of the heat source in the workshop influenced heavily the air flow and temperature distribution. When the heat source was placed at the workshop centre, the heat distribution factor was minimal, the average air temperature at operation zone was lowest and the hot air exhausting velocity was highest, the air flow field and temperature distribution was reasonable for the natural ventilation. When the heat source was placed to be close to the air inlet opening, the fresh air would travel a short path and directly rise to exit and the fresh air did not reach to the right part of the workshop, leading to a possible accumulation of pollutant emission there. When the heat source was placed at the right side of the workshop, the benefit would be that the possible pollutant could be taken away by the air flow, however, the ventilation rate decreased.

Natural-Ventilation Flow in a 3-D Room Fitted With Solar Chimney

2012 ◽  
Author(s):  
B. P. Huynh
Keyword(s):  
Heat Flux ◽  
Flow Pattern ◽  
Natural Ventilation ◽  
Air Flow ◽  
Ventilation Rate ◽  
High Heat Flux ◽  
Solar Chimney ◽  
Solar Heat ◽  
Solar Heat Flux ◽  
Inlet Opening

Natural-ventilation flow induced in a real-sized rectangular-box room fitted with a solar chimney on its roof is investigated numerically, using a commercial CFD (Computational Fluid Dynamics) software package. The chimney in turn is in the form of a parallel channel with one plate being subjected to uniform solar heat flux. Ventilation rate and air-flow pattern through the room are considered in terms of the heat flux for two different locations of the room’s inlet opening. Chien’s turbulence model of low-Reynolds-number K-ε is used in a Reynolds-Averaged Navier-Stokes (RANS) formulation. It is found that ventilation flow rate increases quickly with solar heat flux when this flux is low, but more gradually at higher flux. At low heat flux, ventilation rate is not significantly affected by location of the inlet opening to the room. On the other hand, at high heat flux, ventilation rate varies substantially with the opening’s location. Location of the inlet opening to the room also affects strongly the air-flow pattern. In any case, ample ventilation rate is readily induced by the chimney.

Numerical Simulation of Natural Ventilation in Large-Scale Industrial Workshops Based on Orthogonal Test Design

2013 ◽  
Author(s):  
Yan Long ◽  
Jinming Feng ◽  
Ke Liu ◽  
Shiping Jin ◽  
Yan Fu
Keyword(s):  
Heat Source ◽  
Large Scale ◽  
Natural Ventilation ◽  
Orthogonal Test ◽  
Outdoor Environment ◽  
Industrial Plant ◽  
Test Design ◽  
Range Analysis ◽  
Orthogonal Test Design ◽  
Cfd Method

In this paper, orthogonal test design method and the CFD method were used to study the different building envelopes, and the outdoor environment of natural ventilation effect of single span of high temperature industrial workshop. Firstly, 18 ventilation models of workshop with heat source were constructed with orthogonal test design. Secondly, 18 ventilation models of workshop with heat source were simulated with CFD method. Finally, the order of the influencing factors on the ventilation of workshop was obtained through multiple index range analysis of the orthogonal experiment results according to the average temperature inside the workshop. Then the optimal combination of the best ventilation effect was selected. The research results can provide effectively theoretical basis for the future industrial plant ventilation design and optimization.

Air Flow Modelling of a Multi-Storey Office Building

2013 ◽  
Vol 361-363 ◽  
pp. 833-844
Author(s):  
Chong Jie Wang ◽  
Wei Wei Liu
Keyword(s):  
Temperature Distribution ◽  
Natural Ventilation ◽  
Air Flow ◽  
Comfort Level ◽  
Office Building ◽  
Temperature Stratification ◽  
Air Distribution ◽  
Flow Modelling ◽  
Ventilation Strategies

Indoor fresh air distribution, temperature stratification and temperature distribution are consider to be the essential indicators when comes to evaluation of the comfort level for internal ventilation environment, particularly for natural ventilated space as target office building. It can be identified that the targeting building has been well designed in the respect of natural ventilation strategies where both cross and stack strategies have been adopted, but it is also obvious that under combined buoyancy and wind driven mode alternative problems appears.

Modeling of Buoyancy-Driven Natural Ventilation in Workshop: Optimization of Distance between Heat Source and Ground

2012 ◽  
Vol 170-173 ◽  
pp. 2579-2582 ◽  
Author(s):  
Ya Xin Su ◽  
A Long Su ◽  
Xin Wan
Keyword(s):  
Heat Source ◽  
Indoor Air ◽  
Energy Cost ◽  
Lower Energy ◽  
Natural Ventilation ◽  
Waste Heat ◽  
Heat Sources ◽  
Hot Air ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

Natural ventilation is suitable for application to workshops with heat sources to keep good indoor air quality at lower energy cost. In this paper, the authors numerically investigated the buoyancy-driven natural ventilation in a workshop with heat source based on computational fluid dynamics (CFD) method. The effect of the distance between heat source and ground on the air flow and temperature distribution was examined. Results showed that the average air temperature at operation zone could be effectively reduced when the distance between heat source and ground increased. The temperature field in the upper zone of the workshop was improved by diminishing the hot air zone near the ceiling and the waste heat directly going into the operation zone decreased when the distance between heat source and ground increased.

Modeling of Natural Ventilation in Built-in Photovoltaic-Trombe Wall

2013 ◽  
Vol 448-453 ◽  
pp. 1537-1541 ◽  
Author(s):  
Xiao Wei Xu ◽  
Ya Xin Su
Keyword(s):  
Solar Radiation ◽  
Natural Ventilation ◽  
Reverse Flow ◽  
Volume Flow Rate ◽  
Ventilation Rate ◽  
Volume Flow ◽  
Channel Width ◽  
Air Volume ◽  
Trombe Wall ◽  
Cfd Method

The natural ventilation in a novel built-in photovoltaic-Trombe wall (BiPV-TW) was numerically simulated by CFD method. The effect of solar radiation and channel width on the airflow pattern and ventilation rate was analyzed. Results showed that the solar radiation and channel width influenced the ventilation rate remarkably. As the solar radiation increased, the ventilation rate increased. As the channel width increased from 0.1m to 0.4m, the ventilation rate monotonously increased. However, when the channel width exceeded 0.5m, the reverse flow was formed in the tope zone and the ventilation rate decreased. A maximum air volume flow rate was achieved when the channel width was approximately equal to 0.4m in a 3m tall model.

Effect of Inlet Location on Ventilation Flow Through a Room Fitted With Solar Chimney

2018 ◽  
Author(s):  
Kashif Nazir ◽  
B. P. Huynh
Keyword(s):  
Solar Radiation ◽  
Flow Pattern ◽  
Natural Ventilation ◽  
Air Flow ◽  
Ventilation Rate ◽  
Navier Stokes ◽  
Computational Domain ◽  
Solar Chimney ◽  
Flow Through ◽  
Inlet Opening

Solar chimney (thermal chimney) is a device which absorbs solar radiation to heat the air. The heated air, becoming buoyant, rises through the chimney’s passage and induces further air currents. When fitted to a building, solar chimney can thus induce fresh outside air to flow through the building for ventilation. Because only natural means (solar radiation here) are involved to cause the air flow, solar chimney is considered a natural-ventilation device. This work investigates computationally natural ventilation induced by a roof-mounted solar chimney through a real-sized 3-dimensional room, using a commercial CFD (Computational Fluid Dynamics) software package which employs the Finite Volume Method. Chien’s turbulence model of low-Reynolds-number K-ε is used in a Reynolds-Averaged Navier-Stokes (RANS) formulation. Computational domain that includes regions outside the room’s inlet opening and chimney’s exit allows for employing realistic boundary conditions for the computational model. Ventilation rate and air-flow pattern through the room are considered in terms of the location of the room’s inlet opening. It is found that while ventilation flow-rate through the room is higher with the room-inlet opening being located high on the wall opposite to the chimney’s entrance, a room-inlet opening being located near the ground results in better flow pattern with more flow through the living area in the lower part of the room.

Numerical Simulation of the Natural Ventilation in Workshop with Different Air Inlet Openings

2011 ◽  
Vol 250-253 ◽  
pp. 3187-3190 ◽  
Author(s):  
Ya Xin Su ◽  
Xin Wan
Keyword(s):  
Natural Ventilation ◽  
Temperature Fields ◽  
Heat Distribution ◽  
Heat Sources ◽  
Distribution Factor ◽  
Discrete Ordinate ◽  
Air Inlet ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Inlet Opening

The authors numerically simulated the natural ventilation in an industrial workshop with heat sources by computational fluid dynamics (CFD) method when the height of air inlet opening was set different values. The flow and temperature fields in the workshop were simulated by realizable k-e turbulent model combined with a Discrete Ordinate (DO) radiation. Results showed the height of air inlet opening strongly influenced the flow and temperature fields in the workshop. When the height of air inlet opening increased, the natural ventilation was improved and more fresh air flowed into the workshop. When the height of air inlet opening increased from 1.7 meters to 3 meters, the temperature in the operation zone of the workshop dropped. When the height of air inlet opening increased from 2.7 meters to 3.7 meters, the temperature in operation zone did not change much, while the temperature in the upper zone of the workshop dropped. The heat distribution factor decreased first with the height of air inlet opening and then increased again. When the height of air inlet opening was 3 meters, the heat distribution factor was minimal.

CFD investigation of temperature distribution, air flow pattern and thermal comfort in natural ventilation of building using solar chimney

2020 ◽  
Vol 17 (1) ◽  
pp. 78-86 ◽  
Author(s):  
Maher Dhahri ◽  
Hana Aouinet
Keyword(s):  
Heat Flux ◽  
Temperature Distribution ◽  
Thermal Comfort ◽  
Natural Ventilation ◽  
Air Flow ◽  
Solar Chimney ◽  
Air Velocity ◽  
Content Type ◽  
Solar Heat ◽  
Solar Heat Flux

Purpose The purpose of this study is to investigate air flow, temperature distribution and thermal confort in natural ventilation induced by solar chimney for different operating. Design/methodology/approach Numerical simulation is performed using a commercial computational fluid dynamics (CFD) package ANSYS CFX software to understand the effects of air temperature, air velocity and solar heat flux on the performance of the solar chimney and thermal comfort. The comfort level was evaluated using the air diffusion performance index (ADPI) according to ASHRAE (55-210). The flow was investigated at inclination angles 45° solar heat flux 550-750 W/m2 and in a solar chimney of 1.4 m length, 0.6 m width and 0.20 m air gab. Findings The numerical results from the present simulation were first validated with experimental data, which was used for the thermal comfort indexes calculation. The obtained results of the analysis showed that the used numerical technique could accurately predict air flow and temperature distribution in natural ventilated building using solar chimney; the air temperature, air velocity and solar heat flux have a significant impact on thermal comfort; the temperature of 19°C with velocity of 0.15 m.s−1 gives the best effective draft temperature (EDT) satisfy ASHRAE (55-210) criteria that V = 0.35 m.s−1 and EDT range between −1.7 and 1.1. Originality/value In the present paper, air flow, temperature distribution and thermal comfort inside a room equipped with inclined solar chimney were numerically investigated and analyzed. The commercial CFD package (CFX 15) is used. Calculations are carried out in an empty room without any human or mechanical activity and the numerical results are compared with measurement points.

Effect of Skylight Width on Natural Ventilation in Industrial Workshop

2012 ◽  
Vol 446-449 ◽  
pp. 2904-2907
Author(s):  
Ya Xin Su ◽  
Xin Wan ◽  
A Long Su
Keyword(s):  
Natural Ventilation ◽  
Waste Heat ◽  
Ventilation Rate ◽  
Heat Sources ◽  
Indoor Temperature ◽  
Hot Air ◽  
Temperature Environment ◽  
Computational Fluid Dynamics Cfd ◽  
Higher Temperature ◽  
Cfd Method

The authors numerically simulated the natural ventilation in an industrial workshop with heat sources by computational fluid dynamics (CFD) method and the effect of skylight size on the indoor temperature, ventilation rate and air flow patterns inside the workshop was discussed in detail. Realizable k- turbulent model was used to calculate the flow. Results show that a larger skylight width improves the ventilation. The average air temperature at operation zone decreases and the waste heat directly going into the operation zone decreases when the skylight width increases. The ventilation rate increases very slightly when the skylight width increases from 6 meters to 9 meters, while it increases sharply when w exceeds 10 meters. When the skylight width increases, more hot air is exhausted and the higher temperature environment in the upper zone of the workshop is improved.

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