Optimization of Window Positions for Wind-Driven Natural Ventilation Performance

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.

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A Verification and Validation Study of CFD Simulation of Wind-Induced Ventilation on Building with Single-Sided Opening

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.554.696 ◽

2014 ◽

Vol 554 ◽

pp. 696-700 ◽

Cited By ~ 2

Author(s):

Nur Farhana Mohamad Kasim ◽

Sheikh Ahmad Zaki ◽

Mohamed Sukri Mat Ali ◽

Ahmad Faiz Mohammad ◽

Azli Abd Razak

Keyword(s):

Open Source Software ◽

Natural Ventilation ◽

Cfd Simulation ◽

Previous Experiment ◽

Experimental Methods ◽

Verification And Validation ◽

Navier Stokes ◽

Navier Stokes Equation ◽

Computational Fluid Dynamics Cfd ◽

Model Approach

Wind-induced ventilation is widely acknowledged as one of the best approaches for inducing natural ventilation. Computational fluid dynamics (CFD) technique is gaining popularity among researchers as an alternative for experimental methods to investigate the behavior of wind-driven ventilation in building. In this present paper, Reynolds averaged Navier-Stokes equation (RANS) k-ε model approach is considered to simulate the airflow on a simplified cubic building with an opening on a single façade. Preliminary simulation using models from previous experiment indicates the reliability of OpenFOAM, the open source software that will be used in this study. The results obtained in this study will better define options for our future study which aims to explore how different buildings arrays modify the airflow inside and around a naturally ventilated building.

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Effect of Buoyancy and Density Ratio on Heat Transfer in a Smooth Cooling Channel of a Gas Turbine Blade

Volume 5A: Heat Transfer ◽

10.1115/gt2018-76093 ◽

2018 ◽

Author(s):

Mandana S. Saravani ◽

Saman Beyhaghi ◽

Ryoichi S. Amano

Keyword(s):

Heat Transfer ◽

Rotational Speed ◽

Cfd Simulation ◽

Density Ratio ◽

Reynolds Numbers ◽

Buoyancy Effect ◽

Square Channel ◽

First Case ◽

Computational Fluid Dynamics Cfd ◽

The Impact

The present work investigates the effects of buoyancy and density ratio on the thermal performance of a rotating two-pass square channel. The U-bend configuration with smooth walls is selected for this study. The channel has a square cross-section with a hydraulic diameter of 5.08 cm (2 inches). The lengths of the first and second passes are 514 mm and 460 mm, respectively. The turbulent flow enters the channel with Reynolds numbers of up to 34,000. The rotational speed varies from 0 to 600 rpm with the rotational numbers up to 0.75. For this study, two approaches are considered for tracking the buoyancy effect on heat transfer. In the first case, the density ratio is set constant, and the rotational speed is varied. In the second case, the density ratio is changed in the stationary case, and the effect of density ratio is discussed. The range of Buoyancy number along the channel is 0–6. The objective is to investigate the impact of Buoyancy forces on a broader range of rotation number (0–0.75) and Buoyancy number scales (0–6), and their combined effects on heat transfer coefficient for a channel with aspect ratio of 1:1. Several computational fluid dynamics (CFD) simulation are carried out for this study, and some of the results are validated against experimental data.

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The Potential of Natural Ventilation in Single-Sided Ventilated Apartment to Improve Indoor Thermal Comfort and Air Quality

ASME 2011 5th International Conference on Energy Sustainability, Parts A, B, and C ◽

10.1115/es2011-54129 ◽

2011 ◽

Cited By ~ 1

Author(s):

M. F. Mohamed ◽

M. Behnia ◽

S. King ◽

D. Prasad

Keyword(s):

Air Quality ◽

Thermal Comfort ◽

Indoor Air Quality ◽

Indoor Air ◽

Natural Ventilation ◽

Architectural Element ◽

Flat Design ◽

Effective Ventilation ◽

Computational Fluid Dynamics Cfd ◽

Ventilation Performance

Cross ventilation is a more effective ventilation strategy in comparison to single-sided ventilation. In the NSW Residential Flat Design Code1 (RFDC) the majority of apartments are required to adopt cross ventilation. However, in the case of studio and one-bedroom apartments, it is acknowledged that single-sided ventilation may prevail. Deep plan studio and one-bedroom apartments may achieve lower amenity of summer thermal comfort and indoor air quality where mechanical ventilation is not provided by air conditioning. Since compliance with the code may allow up to 40% of apartments in a development in Sydney to be single sided, it is important to understand the natural ventilation performance of such apartments. The objective of this paper is to investigate the natural ventilation potential in single-sided ventilated apartments to improve indoor air quality and thermal comfort. This investigation includes simulating various facade treatments involving multiple opening and balcony configurations. Balcony configurations are included in this study because, in Sydney, a balcony is a compulsory architectural element in any apartment building. The study uses computational fluid dynamics (CFD) software to simulate and predict the ventilation performance of each apartment configuration. This study suggests that properly configured balconies and openings can significantly improve indoor ventilation performance for enhanced indoor air quality and thermal comfort, by optimizing the available prevailing wind. However, it is important to note that inappropriately designed fac¸ade treatments also could diminish natural ventilation performance.

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Group Layout Pattern and Outdoor Wind Environment of Enclosed Office Buildings in Hangzhou

Energies ◽

10.3390/en13020406 ◽

2020 ◽

Vol 13 (2) ◽

pp. 406 ◽

Cited By ~ 3

Author(s):

Xiaoyu Ying ◽

Yanling Wang ◽

Wenzhe Li ◽

Ziqiao Liu ◽

Grace Ding

Keyword(s):

Natural Ventilation ◽

Cfd Simulation ◽

Simulation Software ◽

Office Building ◽

Wind Environment ◽

Site Model ◽

Advantages And Disadvantages ◽

Building Layout ◽

Ventilation Performance ◽

Group Layout

This paper presents a study of the effects of wind-induced airflow through the urban built layout pattern using statistical analysis. This study investigates the association between typically enclosed office building layout patterns and the wind environment. First of all, this study establishes an ideal site model of 200 m × 200 m and obtains four typical multi-story enclosed office building group layouts, namely the multi-yard parallel opening, the multi-yard returning shape opening, the overall courtyard parallel opening, and the overall courtyard returning shape opening. Then, the natural ventilation performance of different building morphologies is further evaluated via the computational fluid dynamics (CFD) simulation software Phoenics. This study compares wind speed distribution at an outdoor pedestrian height (1.5 m). Finally, the natural ventilation performance corresponding to the four layout forms is obtained, which showed that the outdoor wind environment of the multi-yard type is more comfortable than the overall courtyard type, and the degree of enclosure of the building group is related to the advantages and disadvantages of the outdoor wind environment. The quantitative relevance between building layout and wind environment is examined, according to which the results of an ameliorated layout proposal are presented and assessed by Phoenics. This research could provide a method to create a livable urban wind environment.

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Practical natural ventilation performance metric based on thermal autonomy for sustainable building design

E3S Web of Conferences ◽

10.1051/e3sconf/201911103062 ◽

2019 ◽

Vol 111 ◽

pp. 03062

Author(s):

Kyosuke Hiyama ◽

Liwei Wen

Keyword(s):

Natural Ventilation ◽

Building Design ◽

Weather Data ◽

Design Stage ◽

Successful Implementation ◽

Achievement Level ◽

Sustainable Building ◽

Performance Metric ◽

Ventilation Performance ◽

Energy Simulations

Natural ventilation is an essential component in sustainable building design. However, successfully incorporating it remains difficult because the utilizable amounts of ambient energy resources differ according to project conditions such as ambient climates. Moreover, lack of a metric that could encourage an architect to design a proper plan and façade for natural ventilation at the schematic design stage is being recognized as a barrier to successful achievement of natural ventilation. An inappropriate plan and façade would make it impossible to make thorough considerations for successful implementation of natural ventilation at the later design stages. To encourage even the architects without special expertise in natural ventilation, the metric should be as simple as possible to evaluate the achieved natural ventilation design intuitively and rationally. This paper proposes net Thermal Autonomy as a modified metric of Thermal Autonomy, which cannot easily evaluate the achievement level because the applied weather data significantly influence the calculated value. In the proposed metric, a universal threshold covering climate factors is available by applying net time, while the outdoor condition suitable for natural ventilation is used in the denominator. The practicality of the proposed metric is examined through parametric building energy simulations and analyses.

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

Journal of Computational Engineering ◽

10.1155/2014/310358 ◽

2014 ◽

Vol 2014 ◽

pp. 1-15 ◽

Cited By ~ 4

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.

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The Research of Temperature Fields in the Proximity of a Bundle of Heated Pipes Arranged Above Each Other

Journal of Heat Transfer ◽

10.1115/1.4036041 ◽

2017 ◽

Vol 139 (8) ◽

Cited By ~ 1

Author(s):

Jozef Cernecky ◽

Zuzana Brodnianska ◽

Przemysław Błasiak ◽

Jan Koniar

Keyword(s):

Heat Transfer ◽

Cfd Simulation ◽

Temperature Fields ◽

Horizontal Shift ◽

Geometric Conditions ◽

Interferometry Method ◽

Computational Fluid Dynamics Cfd ◽

Transfer Parameters ◽

C 50 ◽

The Impact

The paper deals with the research of temperature fields in the proximity of heated pipes arranged above each other in a natural air convection. The holographic interferometry method was used for the visualization of temperature fields. The experiments were made with pipes, diameter of 20 mm, length 200 mm, spacing two-dimensional (2D) at surface temperatures of 40 °C, 50 °C, and 60 °C, with the vertical arrangement of the pipes as well as with the horizontal shift of their centers by 1/4D and 1/2D (on a surface temperature of 50 °C). Temperature profiles were determined from the experimentally obtained images of temperature fields, and local parameters of heat transfer were calculated. Under the same marginal and geometric conditions, computational fluid dynamics (CFD) simulations of temperature fields were performed as well, while the results (temperature fields, local and mean parameters of heat transfer) were also calculated for various distances between the pipe centers (1D, 2D, and 3D). From the obtained experimental results and CFD simulation results, it is possible to observe the impact of the arrangement and spacing of pipes on heat transfer parameters. The achieved results imply the change in the spacing of the pipes has a greater impact on heat transfer parameters in the bundle of heated pipes located above each other than a moderate horizontal shift of their centers.

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Test and Simulation of the Effects of Surface Roughness on a Shrouded Centrifugal Impeller

Volume 2D: Turbomachinery ◽

10.1115/gt2014-25480 ◽

2014 ◽

Cited By ~ 1

Author(s):

William T. Cousins ◽

Lei Yu ◽

Jacquelynn Garofano ◽

Barbara Botros ◽

Vishnu Sishtla ◽

...

Keyword(s):

Surface Roughness ◽

Cfd Simulation ◽

Centrifugal Impeller ◽

Test Results ◽

Cfd Simulations ◽

Computational Fluid Dynamics Cfd ◽

The Common ◽

R Value ◽

The Impact ◽

Grain Roughness

Surface roughness is an important parameter in the operational efficiency and loss development of turbomachinery components. Many computational fluid dynamics (CFD) simulations are performed on turbomachinery, but often one of the common assumptions is that the surfaces are hydraulically smooth. In this work, examination of the surfaces of two cast impellers is performed and compared to machined impellers with smoother surfaces. Both impeller sets were run in a two-stage industrial chiller unit using R134a refrigerant. Test results are presented and the impact of surface roughness modeling on the design is reviewed. Also discussed is the theory of the impact of roughness on turbulent boundary layers. Details about providing the CFD simulation with the proper sand grain roughness is discussed when surface finish (R-value) in microinches (μin) is measured.

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

Applied Sciences ◽

10.3390/app11198966 ◽

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.

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Natural Ventilation of Toilet Units in K–12 School Restrooms Using CFD

Energies ◽

10.3390/en14164792 ◽

2021 ◽

Vol 14 (16) ◽

pp. 4792

Author(s):

Yi-Pin Lin

Keyword(s):

Public Schools ◽

Architectural Design ◽

Natural Ventilation ◽

Ventilation Rate ◽

Design Parameters ◽

Ventilation Efficiency ◽

Computational Fluid Dynamics Cfd ◽

Odor Pollution ◽

Window Area ◽

K 12

In this study, the influence of architectural design parameters (the exterior window area, the wall height at a corridor-side, and the door gap of a toilet unit) on the airflow patterns and malodorous volatile substance (acetic acid) distributions within toilet units were investigated via computational fluid dynamics (CFD), with the restrooms in K–12 public schools (kindergarten through grade 12) of Taiwan as research objects. The results show that when there is a 2 m/s north wind in winter, all the cases exceed the required 12 air changes per hour (ACH), and most are above 43.75 ACH. When there is a 0.5 m/s south wind in summer, nearly half of the cases fail to reach 12 ACH. Maintaining an adequate natural ventilation rate and an acceptable level of odor pollution through passive design and architectural design is difficult. Thinking about how to improve the ventilation efficiency of toilet units with the aid of simple, appropriate, and energy-saving mechanical ventilation approaches is necessary.

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