CFD evaluation of natural ventilation of indoor environments by the concentration decay method: CO2 gas dispersion from a semi-enclosed stadium

Hooff, van Taj Twan; Blocken, Bje Bert

doi:10.1016/j.buildenv.2012.11.021

Cited by 126 publications

(60 citation statements)

References 75 publications

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“…In similar research work, the research group led by Blocken presented excellent comparisons [59][60][61][62][63][64]. However, if the experimental data is not easily obtainable due to difficulty in experiments or incomplete experiments, a commonly used method is to perform sub-configuration validation whose actual configuration consists of a number of generic sub-configurations, each of which contains one or several salient flow features in the actual configuration [58,65,66].…”

Section: Validation Proceduresmentioning

confidence: 99%

Improvement of Air Quality and Thermal Environment in an Old City District by Constructing Wind Passages

et al. 2015

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A case study in an old city district with hot-humid climatic conditions in Wuhan, China was conducted to explore the potential renewal strategies favorable to the local residents and pedestrians. For this purpose, a comprehensive mathematical model considering the parameters such as ambient crosswind, solar radiation, natural convection, and a previously established heat transfer mechanism was employed to analyze the fluid flow and heat transfer characteristics of the study area. In addition, in the urban renewal process, five alternative renewal strategies, namely, Central Demolition (CD) Plan, Edge Demolition (ED) Plan, Wedge Shape Demolition (WSD) Plan, "L" Shape Demolition (LSD) Plan, and Cross Shape Demolition (CSD) Plan, were adopted to improve the thermal and ventilation environment of Wuhan old city district. Through simulation analysis, the temperature and velocity distributions of the original urban layout and five alternative renewal strategies were compared. It is found that the construction of an air passage within the old city district can improve the local air quality, air ventilation, and thermal environment to some extent. Among the five alternative strategies to construct air passages, CSD Plan is much better than the others. Accordingly, corresponding suggestions and strategies for urban renewal were presented. OPEN ACCESSSustainability 2015, 7 12673

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Section: Validation Proceduresmentioning

confidence: 99%

Improvement of Air Quality and Thermal Environment in an Old City District by Constructing Wind Passages

et al. 2015

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“…As a result, the velocity of the flow in part that is tangent to the surface falls close to zero [15,20,22]. However, due to difficulty in creating ABL flow for the experiment, a simulation with a uniform velocity profile is performed so as to compare consistently with measurement results by varying the wind speed.…”

Section: Sensitivity Analysismentioning

confidence: 99%

“…CFD was exploited by Stavrakakis et al [4] and Shetabivash [21], and the CFD model was verified using available climatic and experimental data to investigate the effect of the opening on the airflow characteristics of the room and suggest optimum design variables for good ventilation. Additionally, studies have been conducted based on CFD, full-scale and reduced-scale measurements and have focused on natural ventilation through windows with varying factors, such as their types, opening angles, dimensions, opening configuration, building orientations, air velocities, and temperature differences [12][13][14][15][17][18][19][20][21][22][23][24]. Despite the abundance of research, most of the studies on the design and optimization of window openings for better ventilation and thermal comfort have been implemented for residential buildings, and minimal research has focused on industrial windows.…”

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confidence: 99%

Computational and Experimental Investigation for an Optimal Design of Industrial Windows to Allow Natural Ventilation during Wind-Driven Rain

Prueksakorn

Piao²,

Ha³

et al. 2015

Sustainability

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Abstract:With an increased awareness of sustainability issues, natural ventilation has become an elegant method for reducing the costs and environmental effects of the energy that is used to maintain comfortable indoor air quality rather than using mechanical ventilation. The windows in many industrial buildings are continuously open to exhaust pollutants and intake fresh air. Though windows are functional and efficient for natural ventilation, rainwater is able to penetrate through the windows during wind-driven rain. For industries in which the moisture content affects the quality of the product, the intrusion of a large amount of rainwater through windows must be prevented without compromising the effective ventilation. The aim of this research is to determine an innovative design for windows to accomplish the optimum of high ventilation and low rain penetration. For this purpose, windows are variously innovated and tested in full-scale measurements, reduced-scale wind-tunnel measurements and computational fluid dynamics (CFD). An artificial rain and wind velocity to mimic the average of the maximum values in Korea are created. The maximum reduction in rain OPEN ACCESS Sustainability 2015, 7 10500 penetration of over 98% compared to basic 90° open windows is attained with only a 4%-9% decrement of ventilation efficiency in the two recommended designs.

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“…The practice guidelines for setting the upstream and downstream ground are followed to reproduce a horizontally homogeneous atmospheric boundary layer surrounding urban areas [46,57]: The roughness height k S and the roughness constant C S are correlated by the aerodynamic roughness length z 0 :…”

Section: Model Description In the Cfd Validation Casementioning

confidence: 99%

“…It depends on several time scales, i.e., the overall turn over time (air volume (Vol) divided by the total volumetric flow rate (Q T )), purging time for air moving from entrances to exits, time constant for local vortices and turbulent mixing. The concentration decay method has been widely used to predict the actual ACH and age of air in indoor environments in which the concentration temporal profile accords with the exponential decay law and the concentration decay history shows the pollutant dilution and ventilation processes in room ventilation [32][33][34][35][36]45,46]. However, to date, this method has not been introduced to quantify the actual or net ACH index and age of air in UCL models.…”

Section: Introductionmentioning

confidence: 99%

Impacts of Urban Layouts and Open Space on Urban Ventilation Evaluated by Concentration Decay Method

et al. 2017

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Previous researchers calculated air change rate per hour (ACH) in the urban canopy layers (UCL) by integrating the normal component of air mean velocity (convection) and fluctuation velocity (turbulent diffusions) across UCL boundaries. However they are usually greater than the actual ACH induced by flow rates flushing UCL and never returning again. As a novelty, this paper aims to verify the exponential concentration decay history occurring in UCL models and applies the concentration decay method to assess the actual UCL ACH and predict the urban age of air at various points. Computational fluid dynamic (CFD) simulations with the standard k-ε models are successfully validated by wind tunnel data. The typical street-scale UCL models are studied under neutral atmospheric conditions. Larger urban size attains smaller ACH. Keywords: small open space; air change rate per hour (ACH); concentration decay method; urban age of air; computational fluid dynamic (CFD) simulation

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CFD evaluation of natural ventilation of indoor environments by the concentration decay method: CO2 gas dispersion from a semi-enclosed stadium

Cited by 126 publications

References 75 publications

Improvement of Air Quality and Thermal Environment in an Old City District by Constructing Wind Passages

Improvement of Air Quality and Thermal Environment in an Old City District by Constructing Wind Passages

Computational and Experimental Investigation for an Optimal Design of Industrial Windows to Allow Natural Ventilation during Wind-Driven Rain

Impacts of Urban Layouts and Open Space on Urban Ventilation Evaluated by Concentration Decay Method

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