• Title/Summary/Keyword: urban ventilation

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Air Pollutant Dispersion Phenomena at a Street under a Sky Train Station in Bangkok, Thailand

  • Hiyama, Kyosuke;Hoshiko, Tomomi;Prueksasit, Tassanee;Kato, Shinsuke;Koganei, Makoto
    • International Journal of High-Rise Buildings
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    • v.2 no.2
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    • pp.115-121
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    • 2013
  • The ventilation performance of a street in Bangkok, Thailand, was investigated by performing measurements and conducting a CFD analysis. We focused on a street that was covered by an elevated train station. It was shown that the ventilation efficiency varied drastically depending on the angle between the street and the wind direction. When the wind direction was parallel to the street, the elevated structure had a negative influence, which created higher pollutant concentrations than in locations without elevated structures. However, when the wind direction was perpendicular to the street, the pollutant concentrations in the two situations were similar. Using a CFD analysis and ventilation performance indexes, it was shown that the elevated structure directed the wind flow and enhanced the ventilation efficiency, which positively affected ventilation performance. These kinds of knowledge can lead us to optimize city planning including high-rise buildings with high ventilation efficiency.

Numerical Simulation on the Wind Ventilation Lane and Air Pollutants Transport due to Local Circulation Winds in Daegu Districts (대구지역의 국지순환풍의 환기경로 및 대기오염수송에 관한 수치모의)

  • Koo, Hyun-Suk;Kim, Hae-Dong
    • Journal of the Korean earth science society
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    • v.25 no.6
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    • pp.418-427
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    • 2004
  • Recently, urban planning with consideration of urban climate, represented by the concept of urban ventilation lane is widely practiced in many countries. The concept of urban ventilation lane is mainly aimed to improve the thermal comfort within urban area in summer season. It has also the aim to reduce the urban air pollution by natural cold air drainage flows which are to be intensified by a suitable alignment of buildings as well as use zonings based on scientific reasons. In this study, the prevailing wind ventilation lane of a local wind circulation and around Daegu for a typical summer days was investigated by using a numerical simulation. The transport of air pollutants by the local circulation winds was also investigated by using the numerical simulation model, the RAMS (Reasonal Atmospheric Model System).The domain of interest is the vicinity of Daegu metropolitan city (about 900 km2). The horizontal scale of the area is about 30 km. The simulations were conducted under a late spring synoptic condition with weak gradient wind and almost clear sky. From the numerical experiment, the following three conclusions were obtained: (1) The major wind passages of the local circulation wind generated by radiative cooling over the representative mountains of Daegu (Mt. Palgong and Mt. Ap) were found. The winds blow down along the valley axis over the eastern part of Daegu as a gravity flow during nighttime. (2) At the flatland, the winds blow toward the western part of Daegu through the city center. (3) As the results, the air pollutants were transported toward the western part of Daegu by the winds during nighttime.

Ventilation Corridor Characteristics Analysis and Management Strategy to Improve Urban Thermal Environment - A Case Study of the Busan, South Korea - (도시 열환경 개선을 위한 바람길 특성 분석 및 관리 전략 - 부산광역시를 사례로 -)

  • Moon, Ho-Yeong;Kim, Dong-Pil;Gweon, Young-Dal;Park, Hyun-Bin
    • Korean Journal of Environment and Ecology
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    • v.35 no.6
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    • pp.659-668
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    • 2021
  • The purpose of this study is to propose a ventilation corridor management plan to improve the thermal environment for Busan Metropolitan City. To this end, the characteristics of hot and cool spots in Busan were identified by conducting spatial statistical analysis, and thermal image data from Landsat-7 satellites and major ventilation corridors were analyzed through WRF meteorological simulation. The results showed the areas requiring thermal environment improvement among hot spot areas were Busanjin-gu, Dongnae-gu, industrial areas in Yeonje-gu and Sasang-gu, and Busan Port piers in large-scale facilities. The main ventilation corridor was identified as Geumjeongsan Mountain-Baekyangsan Mountain-Gudeoksan Mountain Valley. Based on the results, the ventilation corridor management strategy is suggested as follows. Industrial facilities and the Busan Port area are factors that increase the air temperature and worsen the thermal environment of the surrounding area. Therefore, urban and architectural plans are required to reduce the facility's temperature and consider the ventilation corridor. Areas requiring ventilation corridor management were Mandeok-dong and Sajik-dong, and they should be managed to prevent further damage to the forests. Since large-scale, high-rise apartment complexes in areas adjacent to forests interfere with the flow of cold and fresh air generated by forests, the construction of high-rise apartment complexes near Geumjeongsan Mountain with the new redevelopment of Type 3 general residential area should be avoided. It is expected that the results of this study can be used as basic data for urban planning and environmental planning in response to climate change in Busan Metropolitan City.

Performance Evaluation of Window Ventilation System for Reducing Indoor particulate matter (실내 미세먼지 저감을 위한 창호형 환기시스템 성능평가)

  • Yang, Young Kwon;Park, Jin Chul
    • Land and Housing Review
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    • v.10 no.3
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    • pp.1-7
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    • 2019
  • Indoor particulate matter(PM) is a carcinogen and needs to be removed and managed. It is generally reduced and removed through ventilation and filtration. Owing to the recent occurrence of high-concentration fine dust and yellow dust in the atmosphere, however, it is difficult to expect the purification of indoor air through the simple introduction of the outside air. For residential buildings, in particular, they are highly dependent on natural ventilation but the lack of natural ventilation is worsening because concerns over the inflow of external pollutants are increasing. Therefore, this study designed and manufactured a window ventilation system that does not require a duct to improve the maintenance and management problems of general ventilation system, and constructed indoor PM concentration change data through performance evaluation.

CFD analysis of ventilation efficiency around an elevated highway using visitation frequency and purging flow rate

  • Huang, Hong;Kato, Shinsuke;Ooka, Ryozo;Jiang, Taifeng
    • Wind and Structures
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    • v.9 no.4
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    • pp.297-313
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    • 2006
  • The concentration of air pollution along roads is higher than the surrounding area because ventilation efficiency has decreased due to the high-density use of space along roads in recent years. In this study, ventilation efficiency around a heavily traffic road covered by an elevated highway and hemmed in along its side by buildings is evaluated using Visitation Frequency (VF, the frequency for pollutant to return to the objective domain) and Purging Flow Rate (PFR, the air flow rate for defining the local domain-averaged concentration). These are analyzed using Computational Fluid Dynamics (CFD) based on the standard $k-{\varepsilon}$ model. The VF and PFR characteristics of four objective domains are analyzed in terms of the changes in wind direction and arrangements of the fencing dividing up and down direction in the road center under the elevated highway. The resulting VFs are more than 1.0 for all cases, which means that pollutants return to the objective domain restricted by the elevated highway and side buildings. The influence of the arrangement of the buildings around the objective domain and the structure in the domain on the VF is substantial. In cases where there are no obstacles under the elevated highway, the local air exchange rate in the domain tends to be improved. Using these indices, the urban ventilation efficiencies between different urban areas can be compared easily.

A Proposal of Direction of Wind Ventilation Forest through Urban Condition Analysis - A Case Study of Pyeongtaek-si - (도시 여건 분석을 통한 바람길숲 조성방향 제시 - 평택시를 사례로 -)

  • SON, Jeong-Min;EUM, Jeong-Hee;SUNG, Uk-Je;BAEK, Jun-Beom;KIM, Ju-Eun;OH, Jeong-Hak
    • Journal of the Korean Association of Geographic Information Studies
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    • v.23 no.4
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    • pp.101-119
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    • 2020
  • Recently, as a plan to improve the particulate matter and thermal environment in the city, urban forests acting as wind ventilation corridor(wind ventilation forest) are promoted nationwide. This study analyzed the conditions for the creation of wind ventilation forest(vulnerable areas of the particulate matter and thermal environment, distribution of wind ventilation forest, characteristics of ventilation corridor) of in Pyeongtae-si, one of the target cities of wind ventilation forest project. Based on the results, the direction of developing on the wind ventilation forest in Pyeongtaek-si was suggested. As a result of deriving areas vulnerable to particulate matter and thermal environment, it was most vulnerable in urban areas in the eastern area of Pyeongtaek-si. Especially, emissions were high from industrial complexes and roads such as the Pyeongtaek-si thermal power plant, ports, and the national road no. 1. The wind ventilation forest in Pyeongtaek-si was distributed with small-scale windgenerating forests, wind-spreading forests, and wind-connection forests fragmented and disconnected. The characteristic of the overall wind ventilation corridor in Pyeongtaek-si is that the cold air generated from Mt.Mubong, etc., strongly flowed into Pyeongtaek-si and flowed in the northwest direction. Therefore, it is necessary to preserve and expand the wind-generating forests in Pyeongtaek-si in the long term, and it was important to create wind-spreading forests and wind-connection forests so that cold air could flow into the vulnerable area. In addition, in industrial complexes and roads where particulate matter is generated, planting techniques should be applied to prevent the spread of particulate matte to surrounding areas by creating wind-spreading forests considering the particulate matter blocking. This study can be used not only as the basis data for wind ventilation forest project in Pyeongtaek-si, but also as the basis data for urban forest creation and management.

Indoor Air Quality Evaluation of Commercial Urban Regeneration Modular Structure According to Space Usage (상업용 도시재생 모듈러 건축물의 공간이용에 따른 실내공기질 평가)

  • Nam, So-Jeong;Kim, Sea-Ryon;Pyung, Woo-Jin;Kang, Yujin;Kim, Sumin
    • Journal of the Korea Furniture Society
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    • v.27 no.3
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    • pp.246-252
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    • 2016
  • From 2000s, modular construction has gained more attention due to many advantages such as reduction of duration, recycling. The modular structure is being used for urban regeneration recently. However, even though most facilities in the modular structures which are used as urban regeneration building are commercial spaces, exhibition spaces, eating and drinking spaces, there are lack of natural or mechanical ventilation systems. Also, there are relatively limited spaces on modular structure characteristic. Therefore, indoor environment performance of four buildings, which are performed as urban regeneration in Seoul, was evaluated by HCHO and $CO_2$ emissions. Consequently, the HCHO and $CO_2$ emissions of the commercial and exhibition spaces were confirmed that can influence on health of occupants. Therefore, the urban regeneration modular structure needs to add local ventilation systems for improvement of indoor air quality to more healthy and comfortable.

Management Strategies of Ventilation Paths for Improving Thermal Environment - A Case Study of Gimhae, South Korea - (도시 열환경 개선을 위한 바람길 관리 전략 - 김해시를 사례로 -)

  • EUM, Jeong-Hee;SON, Jeong-Min;SEO, Kyeong-Ho;PARK, Kyung-Hun
    • Journal of the Korean Association of Geographic Information Studies
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    • v.21 no.1
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    • pp.115-127
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    • 2018
  • This study aims to propose management strategies of ventilation paths for improving urban thermal environments. For this purpose, Gimhae-si in Gyeongsangnamdo was selected as a study area. We analyzed hot spots and cool spots in Gimhae by using Landsat 8 satellite image data and spatial statistical analysis, and finally derived the vulnerable areas to thermal environment. In addition, the characteristics of ventilation paths including wind direction and wind speed were analyzed by using data of the wind resource map provided by Korea Meteorological Administration. As a result, it was found that a lot of hot spots were similar to those with weak wind such as Jinyoung-eup, Jillye-myeon, Juchon-myeon and the downtown area. Based on the analysis, management strategies of ventilation paths in Gimhye were presented as follows. Jinyoung-eup and Jillye-myeon with hot spot areas and week wind areas have a strong possibility that hot spot areas will be extended and strengthened, because industrial areas are being built. Hence, climate-friendly urban and architectural plans considering ventilation paths is required in these areas. In Juchon-myeon, where industrial complexes and agricultural complexes are located, climate-friendly plans are also required because high-rise apartment complexes and an urban development zone are planned, which may induce worse thermal environment in the future. It is expected that a planning of securing and enlarging ventilation paths will be established for climate-friendly urban management. and further the results will be utilized in urban renewal and environmental planning as well as urban basic plans. In addition, we expect that the results can be applied as basic data for climate change adaptation plan and the evaluation system for climate-friendly urban development of Gimhye.

Sustainable Tall Buildings: Summary of Energy-Efficient Design

  • Kheir Al-Kodmany;Mir M. Ali;Paul J. Armstrong
    • International Journal of High-Rise Buildings
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    • v.12 no.2
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    • pp.107-120
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    • 2023
  • Tall buildings are frequently decried as unsustainable due to their excessive energy usage. Early skyscrapers used natural light and ventilation to facilitate human comfort and applied organic materials such as stone, glass, wood, concrete, and terra cotta for cladding and finishes. With the advent of fluorescent lighting, modern heating, ventilation, air-conditioning (HVAC) systems, and thermally sealed curtain walls, tall office buildings no longer had to rely on natural light and ventilation to provide comfort. Energy efficiency was not a significant factor when the operational costs of buildings were relatively inexpensive. However, today's skyscrapers must become more energy-efficient and sustainable due to energy crises and climate change. This paper highlights vital energy-efficient design principles and demonstrates with illustrative case studies how they are applied to tall buildings in various parts of the world. It shows how sustainable environmental systems do not act alone but are integrated with advanced curtain wall systems, sky gardens, and atria, among others, to regulate and sustain thermal comfort and conserve energy.

Analysis and Utilization Strategies of Ventilation Corridor Characteristics in Jeon-ju Area (전주지역의 바람길 특성 분석 및 활용 방안)

  • Eum, Jeong-Hee
    • Korean Journal of Environment and Ecology
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    • v.33 no.3
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    • pp.366-374
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    • 2019
  • This study aims to analyze the characteristics of ventilation corridor and propose its utilization strategies in Jeonju city in order to discuss how to utilize urban ventilation corridors as a planning factor for reducing heat wave impact and fine particle pollution. For these purposes, cold air characteristics such as cold air flow and height of cold air in Jeonju area located in the Honam Jeongmaek were analyzed and major ventilation corridors were specified. Based on them, we proposed mountain management strategies for securing and utilizing ventilation corridors. We used KALM (Kaltluftabflussmodell), a cold air simulation model developed in Germany and identified both the cold air flow and the height of cold air layer generated during 6 hours at night. As a result, the cold air flow generated in the forests located in the northeast and east sides of the Jeonju city became clear and the height of cold air layer increased in the valley terrain and farmland areas with time. In particular, Jeonju City has an ideal structure of urban ventilation corridor. Based on the results, the area where the cold air generation is active was designated as the 'cold air conservation area', and the area requiring the management for the good cold air flow was as the 'cold air management area'. This study is expected to be used as basic data of policy making and research for reducing heat wave impact and fine particle pollution such as climate change adaptation policy and urban forest plans for ventilation corridor composition.