scholarly journals Effects of Lateral Window Position and Wind Direction on Wind-Driven Natural Cross Ventilation of a Building: A Computational Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
M. Z. I. Bangalee ◽  
J. J. Miau ◽  
S. Y. Lin ◽  
M. Ferdows
Keyword(s):  
Wind Direction ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Ventilation Rate ◽  
Experimental Investigations ◽  
Original Design ◽  
Lateral Direction ◽  
Window Position ◽  
Ventilation Performance ◽  
Moderate Range

Energy is saved when an effective natural ventilation system can provide comfort air to the occupants in a building by replacing a mechanical ventilation system. It also minimizes the risk of the environmental pollution and the global warming. A one story, full scale building was considered to carry out a comparative study of three different cases of wind-driven natural (WDN) cross ventilation with the help of computational fluid dynamics (CFD). In each case, the location of window was changed in lateral direction to predict the probable position for optimum ventilation performance and the angle of wind was varied to check the sensitivity of the wind direction on the flow field. After validating the current methodology through two satisfactory comparisons with the experimental investigations, the governing equations subjected to the corresponding boundary conditions were solved using commercial software and then the results were analyzed. A better location for the windows in each case was proposed. The ventilation purpose was served quite well even if the wind angle was changed in a moderate range from the original design. Furthermore, the velocity components, ventilation rate, surface pressure, ventilation time, and so forth in each case were investigated and compared extensively with those in other cases.

Modelling the Acoustical and Airflow Performance of Simple Lined Ventilation Apertures

2005 ◽  
Vol 12 (4) ◽  
pp. 277-292 ◽  
Author(s):  
D J Oldham ◽  
Jian Kang ◽  
M W Brocklesby
Keyword(s):  
Aspect Ratio ◽  
Cross Section ◽  
High Aspect Ratio ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Ventilation Performance ◽  
Acoustic Treatment

The pressure differences that can be used to drive a natural ventilation system are very small and thus large apertures are required to allow sufficient air to enter and leave a building to ensure good air quality or thermal comfort. Large apertures are potential acoustic weak points on a façade and may require some form of acoustic treatment such as absorbent linings, in which case the ventilator is similar to a short section of lined duct. In ducts, the performance of absorbent linings increases with the length of lining and the ratio of the length of lined perimeter to the cross sectional area of the duct. Thus, for a duct of a given cross sectional area, a lining is more effective for a duct with a high aspect ratio than for a duct with a square cross section. However, the high aspect ratio cross section will result in greater flow resistance and impede the airflow performance. In this paper numerical methods are employed to investigate the effect of different configurations of a lined aperture on the acoustical and ventilation performance of the aperture in order to establish the optimum configurations.

scholarly journals A Grey Box Modeling Method for Fast Predicting Buoyancy-Driven Natural Ventilation Rates through Multi-Opening Atriums

2019 ◽  
Vol 11 (12) ◽  
pp. 3239 ◽  
Author(s):  
Peng Xue ◽  
Zhengtao Ai ◽  
Dongjin Cui ◽  
Wei Wang
Keyword(s):  
Natural Ventilation ◽  
Simulated Data ◽  
Ventilation Rate ◽  
Modeling Method ◽  
Predictive Equation ◽  
Evaluation Time ◽  
Ventilation Performance ◽  
Ventilation Rates ◽  
Semi Empirical ◽  
Key Parameter

The utilization of buoyancy-driven natural ventilation in atrium buildings during transitional seasons helps create a healthy and comfortable indoor environment by bringing fresh air indoors. Among other factors, the air flow rate is a key parameter determining the ventilation performance of an atrium. In this study, a grey box modeling method is proposed and a prediction model is built for calculating the buoyancy-driven ventilation rate using three openings. This model developed from Bruce’s neutral height-based formulation and conservation laws is supported with a theoretical structure and determined with 7 independent variables and 4 integrated parameters. The integrated parameters could be estimated from a set of simulated data and in the results, the error of the semi-empirical predictive equation derived from CFD (computational fluid dynamics) simulated data is controlled within 10%, which indicates that a reliable predictive equation could be established with a rather small dataset. This modeling method has been validated with CFD simulated data, and it can be applied extensively to similar buildings for designing an expected ventilation rate. The simplicity of this grey box modeling should save the evaluation time for new cases and help designers to estimate the ventilation performance and choose building optimal opening designs.

scholarly journals Optimization of Window Positions for Wind-Driven Natural Ventilation Performance

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2464
Author(s):  
Nari Yoon ◽  
Mary Ann Piette ◽  
Jung Min Han ◽  
Wentao Wu ◽  
Ali Malkawi
Keyword(s):  
Architectural Design ◽  
Natural Ventilation ◽  
Cfd Simulation ◽  
Design Decision ◽  
Building Facades ◽  
Window Position ◽  
Computational Fluid Dynamics Cfd ◽  
Ventilation Performance ◽  
Energy Simulations ◽  
The Impact

This paper optimizes opening positions on building facades to maximize the natural ventilation’s potential for ventilation and cooling purposes. The paper demonstrates how to apply computational fluid dynamics (CFD) simulation results to architectural design processes, and how the CFD-driven decisions impact ventilation and cooling: (1) background: A CFD helps predict the natural ventilation’s potential, the integration of CFD results into design decision-making has not been actively practiced; (2) methods: Pressure data on building facades were obtained from CFD simulations and mapped into the 3D modeling environment, which were then used to identify optimal positions of two openings of a zone. The effect of the selected opening positions was validated with building energy simulations; (3) results: The cross-comparison study of different window positions based on different geographical locations quantified the impact on natural ventilation effectiveness; and (4) conclusions: The optimized window position was shown to be effective, and some optimal solutions contradicted the typical cross-ventilation strategy.

scholarly journals Assessment of Natural Ventilation System for a Typical Residential House in Poland

2016 ◽  
Vol 22 (3) ◽  
pp. 25-44 ◽  
Author(s):  
Romana Antczak-Jarząbska ◽  
Marek Krzaczek
Keyword(s):  
Natural Ventilation ◽  
Flow Direction ◽  
Air Flow ◽  
Ventilation System ◽  
Winter Season ◽  
Residential Building ◽  
Field Measurements ◽  
Significant Deterioration ◽  
Climate Conditions ◽  
Ventilation Performance

Abstract The paper presents the research results of field measurements campaign of natural ventilation performance and effectiveness in a residential building. The building is located in the microclimate whose parameters differ significantly in relation to a representative weather station. The measurement system recorded climate parameters and the physical variables characterizing the air flow in the rooms within 14 days of the winter season. The measurement results showed that in spite of proper design and construction of the ventilation system, unfavorable microclimatic conditions that differed from the predicted ones caused significant reduction in the efficiency of the ventilation system. Also, during some time periods, external climate conditions caused an opposite air flow direction in the vent inlets and outlets, leading to a significant deterioration of air quality and thermal comfort measured by CO2 concentration and PMV index in a residential area.

scholarly journals Ventilation Characteristics and Performance Evaluation of Different Window-Opening Forms in a Typical Office Room

2021 ◽  
Vol 11 (19) ◽  
pp. 8966
Author(s):  
Yuanyuan Wang ◽  
Yanzhe Yu ◽  
Tianzhen Ye ◽  
Quan Bo
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Cfd Simulation ◽  
Thermal Sensation ◽  
Ventilation Rate ◽  
Window Opening ◽  
Ventilation Modes ◽  
Ventilation Performance ◽  
Scale Experiment ◽  
And Performance

As most existing office buildings in China lack fresh air systems for ventilation, natural ventilation with windows remains the main means of improving indoor air quality and adjusting indoor thermal comfort. However, knowledge of the ventilation characteristics of various window-opening forms in actual buildings is limited and current methods for evaluating ventilation performance lack a comprehensive consideration of ventilation rate and thermal comfort. In this study, the ventilation characteristics of different window-opening forms were systematically compared by conducting computational fluid dynamics (CFD) simulations. A full-scale experiment was conducted in a typical office room in a university in Tianjin to validate the CFD simulation. Two ventilation modes (wind-driven cross-ventilation and temperature-driven single-sided ventilation), three window-opening angles, and seven window types were investigated. Additionally, the ratio of the ventilation rate to the absolute value of thermal sensation was used to quantify the indoor natural-ventilation performance. The results showed that a sliding window with a full opening has the highest discharge coefficients of 0.68 and 0.52 under wind-driven cross-ventilation and temperature-driven single-sided ventilation, respectively, and top-hung windows opening both inwards and outwards have better ventilation performance than other window types under the two ventilation modes. This study is applicable to the design and practice of natural ventilation.

The impacts of introducing voids combinations on indoor ventilation performance in high-rise residential buildings

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamza Laloui ◽  
Noor Hanita Abdul Majid ◽  
Aliyah Nur Zafirah Sanusi
Keyword(s):  
Architectural Design ◽  
Natural Ventilation ◽  
Residential Buildings ◽  
Design Feature ◽  
Field Measurements ◽  
Ventilation Rate ◽  
Content Type ◽  
High Rise ◽  
Building Models ◽  
Ventilation Performance

PurposeThe paper aims to investigate and evaluate the impacts of the voids combination as a passive design feature on wind-driven ventilation performance in high-rise residential building units. It proposes a series of building models and thereon indoor ventilation performance and outlining why and how these building models designed with architectural design features are important. This study aims to provide a comprehensive understanding of how natural ventilation as a passive cooling strategy in living units of high-rise residential buildings can be applied through improving the provision of the architectural design feature of voids configurations.Design/methodology/approachThe study was carried out through field measurements experiment and the computational fluid dynamics methods. A series of numerical simulations were carried out to calculate the indoor ventilation rate inside the case studies of the generated building models based on various variables such as horizontal voids type, size and wind directions.FindingsThe results indicate that the provision of a single-sided horizontal voids in building models can improve the indoor ventilation rate in units with cross ventilation mode up to 4 times, depending on wind direction and living unit location. The indoor ventilation performance in units located in models with single-sided horizontal voids is 17.54% higher than the units located in models without voids configuration. Furthermore, higher indoor ventilation performance was achieved in the case scenarios located at higher levels compared to the middle and lower levels in both horizontal voids types.Originality/valueThis study explores the application of voids combinations for natural ventilation performance, investigates the numerical simulation results and validates field measurements experiment data using CFD simulation.

Analysis of Natural Ventilation Efficiency of a Passive Solar Chimney in a Conference Hall of the Magic School of Green Technology

2013 ◽  
Vol 368-370 ◽  
pp. 603-606 ◽  
Author(s):  
Chun Han Chien ◽  
Hsien Te Lin
Keyword(s):  
Natural Ventilation ◽  
Ventilation Rate ◽  
Green Technology ◽  
Solar Chimney ◽  
Air Exchange Rate ◽  
Ventilation Efficiency ◽  
Air Ventilation ◽  
Passive Solar ◽  
Ventilation Performance ◽  
Air Exchange

This study focuses on the efficiency of passive solar chimney in natural ventilation performance of the conference hall at the Magic School of Green Technology (MSGT) in Tainan, Taiwan. The air exchange rate in the conference hall was between 5.73 ACH and 9.11 ACH, which exceeded the minimum air ventilation rate required in Taiwan. This shows that a passive solar chimney can effectively applied to the conference hall to meet indoor ventilation and air exchange requirements without using air conditioning.

scholarly journals Numerical Study on Different Series Modes of Jet Fan in a Longitudinal Tunnel Ventilation System

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Guihong Pei ◽  
Jie Pan
Keyword(s):  
Numerical Study ◽  
Ventilation System ◽  
Original Design ◽  
Air Velocity ◽  
Central Plains ◽  
Traffic Condition ◽  
Free Jet ◽  
Combination Modes ◽  
Ventilation Performance ◽  
Combination Mode

Efficient ventilation systems will contribute to maintaining air quality in the tunnel. In order to improve ventilation performance in normal traffic condition, the 3D tunnel models were established according to the original design for the tunnel located in central plains of China. Based on the commercial CFD software Fluent 6.3 andk-εturbulence model, numerical simulations were carried out to study the patterns of jet flow and the optimization of fan combinations. It is found that the axial velocity profile obtained from numerical simulation agrees quite well with turbulent free jet theory although there is a little difference on the magnitude. The comparison of four combination modes under the condition of operating four fans indicates that the ventilation effectiveness is affected mainly by both the interval of adjacent groups of fans and the combination modes of operational fans. According to the simulation results, a novel combination mode which consists of a group double paralleled fans and two groups single fan is designed. The novel combination mode is regarded as the optimum combination mode with respect to maximizing air velocity in the tunnel. Compared to the traditional combination modes, it will increase the air velocity by 5.7%.

Investigation on the Performance of a Trombe Wall Driven by Thermal Pressure

2012 ◽  
Vol 614-615 ◽  
pp. 200-203
Author(s):  
Jun Qin Hou ◽  
Yong Gang Lei ◽  
Fei Wang ◽  
Xun Wang
Keyword(s):  
Numerical Simulation ◽  
Heat Flux ◽  
Heat Flow ◽  
Natural Ventilation ◽  
Ventilation Rate ◽  
Thermal Pressure ◽  
Wall Width ◽  
Trombe Wall ◽  
Ventilation Performance

Numerical simulation was carried out for the ventilation performance of a Trombe wall driven by thermal pressure. The effect of heat flux, the wall width and height to the indoor ventilation were analyzed and discussed. The results show that the increase of heat flow and the height of wall cause the increase of natural ventilation rate while the increase of width cause the increase of ventilation and then deceasing.

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