Mitigating urban heat islands: A method to identify potential wind corridor for cooling and ventilation

Hsieh, Chun-Ming; Huang, Hsin-Chiao

doi:10.1016/j.compenvurbsys.2016.02.005

Cited by 160 publications

(94 citation statements)

References 37 publications

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“…Owing to global warming caused by climate change, various environmental problems are intensifying in urban areas, such as increased heat waves, tropical nights, air pollution and flooding [1,2]. Moreover, the environmental problems in urban areas were even more severe, due to an artificial surface, reduced green space, and air pollution triggered by excessive urban development [3][4][5][6]. Especially, urban heat islands, which occur when the temperature in the urban area is significantly higher than the surrounding areas, is becoming more serious than and intensifies more during the night than in the daytime.…”

Section: Introductionmentioning

confidence: 99%

Management Strategies of Thermal Environment in Urban Area Using the Cooling Function of the Mountains: A Case Study of the Honam Jeongmaek Areas in South Korea

et al. 2018

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The aim of this study is to suggest planning strategies for managing comfortable thermal environments in urban areas by local cold air generated in mountains, which finally contributes to making sustainable and eco-friendly cities. For this purpose, we selected urban areas in the Honam Jeongmaek in Korea and analyzed the nighttime cold airflow and altitude of the cold air layer generated in mountains, by using the KALM (Kaltluftabflussmodell) model which calculates the amount of cold air generated during the nighttime without winds. The results of analysis found that the local airflows generated in Mt. Chuwol, Mt. Mudeung, Mt. Cheonun, Mt. Byeongpung and Mt. Geum influenced the entire study site from across Gwangju Metropolitan City to adjacent areas. Therefore, the mountains generated major cold airflows should be designated as the management area for securing cooling function. As a result of detailed analysis, most developed areas, such as Buk-gu, Seo-gu and Nam-gu, as well as industrial areas, did not have a smooth flow, so management strategies were needed. In particular, Mt. Mudeung and Mt. Cheonun were the source areas of the local cold air generation and the generated flows from the mountains could influence into developed areas of Gwangju Metropolitan City. Thus, thorough preservation policies are required for Mt. Mudeung and Mt. Cheonun from development that causes damages to mountainous terrain and topography. This study could support the establishment of systematic management plans of the Honam Jeongmaek in preparation for climate change. In addition, it is expected to be used to develop policies related to the quantitative expansion of mountain areas with cooling functions and the conservation of sustainable mountain areas.

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Section: Introductionmentioning

confidence: 99%

Management Strategies of Thermal Environment in Urban Area Using the Cooling Function of the Mountains: A Case Study of the Honam Jeongmaek Areas in South Korea

et al. 2018

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“…However, seasonality can make this influence pleasant or unwelcome as follows.In hot weather conditions, the correct design of open spaces will direct wind into an air corridor which can reduce the duration of thermal discomfort [13]. The positive role of wind corridors in creating an acceptable outdoor thermal environment has been well researched [14][15][16][17][18][19] and is recommended as a thermal adaptive strategy for many climate conditions [6,20]. Conversely, in cool seasons, strong wind blows induce thermal discomfort which can be mitigated by windbreakers or shields [21].…”

mentioning

confidence: 99%

“…Conversely, in cool seasons, strong wind blows induce thermal discomfort which can be mitigated by windbreakers or shields [21]. Consequently, the proper design of open spaces has a critical role in the formation of local wind environment and thermal comfort [19,22,23]. Blocken and Carmeliet [5] and later Abd Razak, et al [24] have conducted reviews on literature studying the link between design and pedestrians' wind environment.Capital cities in Australia have undergone significant changes in the last three decades [25].…”

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confidence: 99%

Perception of Wind in Open Spaces

Shooshtarian

Rajagopalan

2019

Climate

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Dense urbanization influences the livability of cities. Changes in local meteorological conditions can be adverse for human health and well-being. In urban open spaces, it is widely known that changes in building density and configuration in cities influence wind speed (V a ). This influence modifies latent heat flux between the human body and surrounding environment and thereby affecting the thermal comfort conditions in open spaces between buildings. Several studies have demonstrated the significant effect of wind speed on outdoor thermal comfort. Melbourne's Central Business District (CBD) has recently experienced dense urbanization and this pattern of development has instigated noticeable changes in meteorological conditions. Some evidence has suggested that the patterns of wind flow induce thermal discomfort during cool seasons. Conversely, the wind is most welcomed during warm seasons. This study was conducted to assess outdoor users' responses to V a in three open spaces of an educational precinct in Melbourne's CBD. The open spaces studied are different in terms of design and function. Users' responses and meteorological conditions were examined through a series of field measurements and questionnaire surveys from November 2014 to May 2015. This study used three perceptual scales to analyze participants' experience of V a during field surveys: "Bedford preference", "thermal sensation" and "personal acceptability". Analytical results yielded the wind perceptual comfort thresholds for different seasons as well as the entire study period. The results suggested that in addition to the geometry of the urban open space, the function of place could influence people's perceptions of V a . The research findings contribute to developing thermally comfortable outdoor environments.Climate 2019, 7, 106 2 of 17 the factors that significantly influence people's thermal comfort, wind speed (V a ) was found to play a key role in cities and particularly in densely built-up areas and between buildings [5,6].Research on wind comfort perception is underpinned by four major methods: software simulations, field tests, wind tunnel tests and questionnaire survey [6]. Questionnaire survey on people's feeling about wind speed is believed to provide accurate, comprehensive and cost-effective method. Since this method evaluates the impact of four parameters (T a , RH, V a, and T mrt ) it is possible to gain an insight into the impact of V a in comparison with the other three parameters. Several studies have demonstrated the significant effect of V a on outdoor thermal comfort [7][8][9]. For instance, the study by Walton, Dravitzki and Donn [7] revealed that gustiness and V a were the most significant factors in shaping outdoor thermal satisfaction. The results of a questionnaire survey in Hong Kong [9] showed that participants were highly sensitive to V a fluctuations. In urban open spaces, it is widely known that recent drastic changes in the design of building density and configuration in cities influence V a profile [5,[10][11][1...

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“…With the rapid urbanization, street canyons appear in cities as more and more high-rise buildings spring up, resulting in poor city ventilation [2]. Stagnant air caused by poor ventilation in street canyons leads to the massive accumulation of pollutants and anthropogenic heat, exacerbating the outdoor air quality [3][4][5] and the Urban Heat Island effect (UHI) [6][7][8][9]. Outdoor environment is essential not only for people directly exposed to the circumstance [10,11], but it also has an important influence on the indoor environment [12].…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Urban Ventilation in Regulating Microclimate and Pollutant Dispersion in Urban Street Canyon: A Case Study of Nanjing New Region, China

et al. 2017

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Abstract:Urban ventilation plays an important role in regulating city climate and air quality. A numerical study was conducted to explore the ventilation effectiveness on the microclimate and pollutant removal in the urban street canyon based on the rebuilt Southern New Town region in Nanjing, China. The RNG k − ε turbulence model in the computational fluid dynamics (CFD) was employed to study the street canyon under parallel and perpendicular wind directions, respectively. Velocity inside of the street canyon and temperature on the building envelopes were obtained. A novel pressure coefficient was defined, and three methods were applied to evaluate the urban ventilation effectiveness. Results revealed that there was little comfort difference for the human body under two ventilation patterns in the street canyon. Air stagnation occurred easily in dense building clusters, especially under the perpendicular wind direction. In addition, large pressure coefficients (C P > 1) appeared at the windward region, contributing to promising ventilation. The air age was introduced to evaluate the "freshness" of the air in the street canyon and illustrated the ventilation effectiveness on the pollutant removal. It was found that the young air distributed where the corresponding ventilation was favorable and the wind speed was large. The results from this study can be useful in further city renovation for the street canyon construction and municipal planning.

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Mitigating urban heat islands: A method to identify potential wind corridor for cooling and ventilation

Cited by 160 publications

References 37 publications

Management Strategies of Thermal Environment in Urban Area Using the Cooling Function of the Mountains: A Case Study of the Honam Jeongmaek Areas in South Korea

Management Strategies of Thermal Environment in Urban Area Using the Cooling Function of the Mountains: A Case Study of the Honam Jeongmaek Areas in South Korea

Perception of Wind in Open Spaces

Numerical Study on the Urban Ventilation in Regulating Microclimate and Pollutant Dispersion in Urban Street Canyon: A Case Study of Nanjing New Region, China

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