scholarly journals Analysis of Natural Ventilation Performance Gap between Design Stage and Actual Operation of Office Buildings

2020 ◽  
Vol 172 ◽  
pp. 09010
Author(s):  
Xiuzhang FU ◽  
Mingzhu HAN
Keyword(s):  
Indoor Air ◽  
Natural Ventilation ◽  
Simulation Software ◽  
Office Buildings ◽  
Design Stage ◽  
Speed Ratio ◽  
Performance Gap ◽  
Window Opening ◽  
Actual Operation ◽  
Ventilation Performance

Suitable natural ventilation in office buildings can not only reduce energy consumption of air conditioning, but also improve indoor air quality. In the architectural design stage, the effect of natural ventilation design is mainly simulated by CFD simulation software for indoor air speed, pressure, and age of air, etc.. However, during the actual building operation, the indoor natural ventilation effect will be affected by many factors, such as surrounding buildings, indoor layout, window position and open-close status, human behavior, etc., and the natural ventilation performance between design stage and actual operation is often different. In this paper, a typical office building was selected and FloVENT software was used to quantitatively analyse the influence of surrounding buildings, indoor layout, door/window opening conditions on indoor natural ventilation. Field measurement of indoor air flow rates in typical positions in office were carried out under different circumstances. In order to reduce the instantiate influence of outdoor wind speeds, a new index named Wind Speed Ratio(WSR) is put forward.Through comparative analysis of simulated data and measured data. the gap degree in natural ventilation performance between design stage and operation operation is discussed, and results show that the relative errors of the WSR, which could be considered to reflect the performance gap, are about 78.0%, 28.7% and 150% respectively, under corresponding condition settings of surrounding buildings, indoor layout, and door/window opening.

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

2011 ◽  
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.

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

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 406 ◽  
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.

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

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.

Numerical Evaluation of Ventilation Efficiency of Window Type Ventilation Systems

2019 ◽  
Vol 27 (03) ◽  
pp. 1950027
Author(s):  
Young Kwon Yang ◽  
Min Young Kim ◽  
Jin Woo Moon ◽  
Jin Chul Park
Keyword(s):  
Mechanical Ventilation ◽  
Indoor Air ◽  
Numerical Evaluation ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Adverse Pressure Gradient ◽  
Building Energy ◽  
Window Opening ◽  
Ventilation Efficiency ◽  
Air Purifier

Ventilation in buildings is the simplest and most convenient way to purify indoor air. However, when the ventilation is not enough due to natural ventilation, it should be cleaned by mechanical ventilation or air purifier. This process requires building energy. Therefore, it is possible to save the energy of the building by merely increasing the natural ventilation efficiency. This study conducted airflow analysis simulations to investigate the effects of changes in the shape of ventilation openings and louvers on the ventilation efficiency of a window ventilation system. The streamlined window opening exhibited a greater increase in airflow (41.3%) than did the conventional window (24.3%) for the ventilation model with four openings. It was also observed that flow separation and wakes were generated by the adverse pressure gradient arising from the increased airflow speed when a louver was employed. Based on these results, it can be concluded that using a louver as a wind augmentation device is an obstacle to improving the airflow in a window ventilation system.

A numerical investigation on the impacts of voids combinations on natural ventilation of high-rise residential building

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamza Laloui ◽  
Noor Hanita Abdul Majid ◽  
Aliyah Nur Zafirah Sanusi
Keyword(s):  
Thermal Comfort ◽  
Indoor Air ◽  
Design Methodology ◽  
Natural Ventilation ◽  
Residential Building ◽  
Air Velocity ◽  
Content Type ◽  
High Rise ◽  
Living Unit ◽  
Ventilation Performance

Purpose This paper aims to investigate the impacts of introducing voids combinations on natural ventilation performance in high-rise residential building living unit. Design/methodology/approach This study was carried out through field measurement and computational fluid dynamics methods. The parameters of the study are void types and sizes, and a wind angle was used to formulate case studies. Findings The results indicate that the provision of a single-sided horizontal void larger by 50% increase the indoor air velocity performance up to 322.37% to 0.471 m/s in the living unit and achieves the required velocity for thermal comfort. Originality/value Passive design features are the most desirable techniques to enhance natural ventilation performance in the high-rise residential apartments for thermal comfort and indoor air quality purposes.

scholarly journals Research on the Impact of Wind Angles on the Residential Building Energy Consumption

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Zou Huifen ◽  
Yang Fuhua ◽  
Zhang Qian
Keyword(s):  
Energy Consumption ◽  
Heat Loss ◽  
Indoor Air ◽  
Wind Direction ◽  
Natural Ventilation ◽  
Building Energy ◽  
Simulation Software ◽  
Outdoor Environment ◽  
Building Energy Consumption ◽  
The Impact

Wind angles affect building’s natural ventilation and also energy consumption of the building. In winter, the wind direction in the outdoor environment will affect heat loss of the building, while in summer the change of wind direction and speed in the outdoor environment will affect the building’s ventilation and indoor air circulation. So, making a good deal with the issue of the angle between local buildings and the dominant wind direction can effectively solve the winter and summer ventilation problems. Thereby, it can enhance the comfort of residential person, improve indoor air quality, solve heat gain and heat loss problems in winter and summer in the severely cold and cold regions, and reduce building energy consumption. The simulation software CFD and energy simulation software are used in the paper. South direction of the building is the prototype of the simulation. The angle between the direction of the building and the outdoor environment wind is changed sequentially. Energy consumption under different wind angle conditions is compared with each other. Combined with natural ventilation under various wind angles, the paper gives the best recommended solution of building direction in Shenyang.

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.

EVALUASI PERFORMA VENTILASI ALAMI PADA DESAIN BUKAAN RUANG KELAS UNIVERSITAS ATMA JAYA YOGYAKARTA

2017 ◽  
Vol 10 (3) ◽  
pp. 149
Author(s):  
Jackobus Ade Prasetya Seputra
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Teaching And Learning ◽  
Natural Ventilation ◽  
Vertical Section ◽  
Case Study Research ◽  
Bottom Layer ◽  
Simulation Software ◽  
Windward Side ◽  
Ventilation Performance

Abstract: Education is an important sector of a nation toward better future. Conducive classroom with well designed room ventilation would encourage occupants in implementing effective teaching and learning activities. Research was conducted to figure out classroom performance and optimization of natural ventilation which was occurred in Engineering Faculty of UAJY represented by the classroom number 2406 as case study. Research is focused on classroom ventilation elements by examining window’s dimension, occupant’s adaptive behavior, opening types, and glass type at windward side. This research implements rationalistic method by utilizing computer simulation software DesignBuilder complemented with CFD in order to analyze and deduce information obtained primarily by field measurement and other relevant literatures. Results generated by DesignBuilder show that changes in ventilation area at external windows have significant influence over room’s ventilation performance. CFD (Computational Fluid Dynamics) experiments were conducted by examining opening types shown on room’s vertical section drawing, opening positions, overhangs, and external louvre types. Results show that experiments conducted by replacing the bottom layer of fixed windows with operable windows has significant effect in improving ventilation performance. Variation on overhangs only produce little impact, yet experiments on external louvres prove that the best type is horizontal louvre. Optimization done by studying above variables is capable to increase ventilation performance up to 800% in examined classroom.Keywords: ventilation, optimization, room openings, computer simulationAbstrak: Sektor pendidikan adalah tulang punggung suatu bangsa demi menuju masa depan yang lebih baik. Ruang kelas yang berkualitas dan kondusif dengan perencanaan sistem ventilasi dalam ruang yang baik bagi kegiatan belajar mengajar akan membantu tercapainya tujuan tersebut. Penelitian ini dilakukan untuk mengetahui sejauh mana performa ventilasi alami ruang dengan studi kasus Ruang Kelas 2406 Gedung Fakultas Teknik UAJY dan bagaimana bentuk optimasinya. Penelitian berfokus pada elemen bukaan dengan berbagai dimensi jendela, pengaturan adaptif penghuni, jenis bukaan ventilasi pada jendela, serta jenis kaca jendela pada sisi windward (angin datang). Metode simulasi komputer diperkuat dengan pengukuran lapangan menjadi alat bantu menakar dan mengoptimalisir kebutuhan ventilasi alami melalui berbagai variasi desain bukaan. Hasil studi dengan DesignBuilder memperlihatkan bahwa variabel luasan ventilasi pada jendela (“external window open”) memiliki pengaruh besar terhadap performa ventilasi alami dalam ruang. Studi dengan CFD (Computational Fluid Dynamics) berfokus pada model bukaan ruang, yaitu model bukaan pada potongan vertikal ruang, posisi bukaan, tipe teritisan (“overhang”) serta kerai (“louvre”) eksternal. Eksperimen pada posisi bukaan inlet menunjukkan bahwa perubahan jendela mati menjadi jendela hidup pada lapis bawah menghasilkan performa ventilasi lebih baik. Studi teritisan tidak memiliki pengaruh besar, sedangkan studi kerai membuktikan bahwa jenis kerai terbaik adalah kerai horisontal. Optimasi ini mampu meningkatkan performa ventilasi hingga 800% pada studi kasus.Kata kunci: ventilasi, optimasi, bukaan ruang, simulasi komputer

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