Predicting comfort levels in cities is challenging due to the many metric assessment.To overcome these challenges,much research is being done in the computing community to develop methods capable of generating outdoor...Predicting comfort levels in cities is challenging due to the many metric assessment.To overcome these challenges,much research is being done in the computing community to develop methods capable of generating outdoor comfort data.Machine Learning(ML)provides many opportunities to discover patterns in large datasets such as urban data.This paper proposes a data-driven approach to build a predictive and data-generative model to assess outdoor thermal comfort.The model benefits from the results of a study,which analyses Computational Fluid Dynamics(CFD)urban simulation to determine the thermal and wind comfort in Tallinn,Estonia.The ML model was built based on classification,and it uses an opaque ML model.The results were evaluated by applying different metrics and show us that the approach allows the implementation of a data-generative ML model to generate reliable data on outdoor comfort that can be used by urban stakeholders,planners,and researchers.展开更多
A thermal stress index of a geographic location over a period of time can provide knowledge of overall climate perceptible to the general public. Out of the three approaches to assessing thermal comfort namely, ration...A thermal stress index of a geographic location over a period of time can provide knowledge of overall climate perceptible to the general public. Out of the three approaches to assessing thermal comfort namely, rational, empirical and direct, the direct approach is being used in the present study because of easy availability of all inputs and reasonable comprehension of the assessments. Assessment and ranking of cities using this approach based on the percentage of comfortable hours alone may however be erroneous and misleading as this approach does not consider the percentages of uncomfortable classes which could often be substantially high. The modified approach for thermal comfort classification demonstrates cumulative representation of all classes of thermal comfort including uncomfortablity and provides relative ranking of cities. Analysis of the results is presented here for five megacities (Delhi, Mumbai, Chennai, Kolkata and Hyderabad) representing varying geographical and climatic locations of India. These cities are ranked based on the routine and modified approaches and results are discussed in detail on monthly, seasonal and annual average basis. When the cities are compared only on the basis of comfortable hours, the decreasing order of comfortability is Hyderabad, Kolkata, Delhi, Chennai and Mumbai. However, considering the second methodology, it is revealed that the contribution of uncomfortable hours is greater in Kolkata and Chennai in comparison to Mumbai. The proposed methodology could be an improvement over the current practices and provides a more rational method for relative ranking of cities that could be used for tourism and energy demands.展开更多
This paper presents a global methodology to compute wind flow in complex urban areas in order to assess wind pedestrian comfort, wind energy, wind safety or natural ventilation potential. The numerical tool presented ...This paper presents a global methodology to compute wind flow in complex urban areas in order to assess wind pedestrian comfort, wind energy, wind safety or natural ventilation potential. The numerical tool presented here is composed of a CFD soft-ware suite covering both regional scale (20 km) and urban scale (1km), and able to model the wind in any complex terrains and in large urban environments. Examples are presented in the paper in order to show the advantages of the methodology for urban designers.展开更多
Skygardens or skycourts are a unique architectural intervention in the built environment,enhancing the social,economic,and environmental values of the building.It allows occupants to connect and experience outdoor fre...Skygardens or skycourts are a unique architectural intervention in the built environment,enhancing the social,economic,and environmental values of the building.It allows occupants to connect and experience outdoor freshness within a semi-enclosed environment.However,skygardens located on a highrise building may generate intense wind gusts,endangering the safety of occupants.Using a validated computational fluid dynamics model,this study investigates the potential of various vegetative barriers or shelterbelts in attenuating the high wind speeds encountered in such spaces and the impact on wind and thermal comfort.Three skygarden configurations were investigated with and without vegetative barriers,simplified and modelled as porous zones,and their effect was studied on the velocity and temperature profile at the occupants’level.The results indicate that while hedges and trees can offer resistance to airflow,trees provide higher temperature reduction.However,a combination of vegetative and geometrical barriers provides the most optimal condition in the skygarden.The study has identified the importance of assessing wind attenuation characteristics of tree plantations on highrise skygarden,and the results can be used in designing intervention strategies.Moreover,vegetation can attenuate pollutants and mitigate poor air quality by surface deposition,and future studies should investigate in that direction.展开更多
基金This work has been supported by the European Commission through the H2020 project Finest Twins(grant No.856602).
文摘Predicting comfort levels in cities is challenging due to the many metric assessment.To overcome these challenges,much research is being done in the computing community to develop methods capable of generating outdoor comfort data.Machine Learning(ML)provides many opportunities to discover patterns in large datasets such as urban data.This paper proposes a data-driven approach to build a predictive and data-generative model to assess outdoor thermal comfort.The model benefits from the results of a study,which analyses Computational Fluid Dynamics(CFD)urban simulation to determine the thermal and wind comfort in Tallinn,Estonia.The ML model was built based on classification,and it uses an opaque ML model.The results were evaluated by applying different metrics and show us that the approach allows the implementation of a data-generative ML model to generate reliable data on outdoor comfort that can be used by urban stakeholders,planners,and researchers.
文摘A thermal stress index of a geographic location over a period of time can provide knowledge of overall climate perceptible to the general public. Out of the three approaches to assessing thermal comfort namely, rational, empirical and direct, the direct approach is being used in the present study because of easy availability of all inputs and reasonable comprehension of the assessments. Assessment and ranking of cities using this approach based on the percentage of comfortable hours alone may however be erroneous and misleading as this approach does not consider the percentages of uncomfortable classes which could often be substantially high. The modified approach for thermal comfort classification demonstrates cumulative representation of all classes of thermal comfort including uncomfortablity and provides relative ranking of cities. Analysis of the results is presented here for five megacities (Delhi, Mumbai, Chennai, Kolkata and Hyderabad) representing varying geographical and climatic locations of India. These cities are ranked based on the routine and modified approaches and results are discussed in detail on monthly, seasonal and annual average basis. When the cities are compared only on the basis of comfortable hours, the decreasing order of comfortability is Hyderabad, Kolkata, Delhi, Chennai and Mumbai. However, considering the second methodology, it is revealed that the contribution of uncomfortable hours is greater in Kolkata and Chennai in comparison to Mumbai. The proposed methodology could be an improvement over the current practices and provides a more rational method for relative ranking of cities that could be used for tourism and energy demands.
文摘This paper presents a global methodology to compute wind flow in complex urban areas in order to assess wind pedestrian comfort, wind energy, wind safety or natural ventilation potential. The numerical tool presented here is composed of a CFD soft-ware suite covering both regional scale (20 km) and urban scale (1km), and able to model the wind in any complex terrains and in large urban environments. Examples are presented in the paper in order to show the advantages of the methodology for urban designers.
基金The support provided by the Faculty of Engineering,University of Nottingham and EPSRC is acknowledged,which includes a scholarship(EP/R513283/1)and computational facilities.
文摘Skygardens or skycourts are a unique architectural intervention in the built environment,enhancing the social,economic,and environmental values of the building.It allows occupants to connect and experience outdoor freshness within a semi-enclosed environment.However,skygardens located on a highrise building may generate intense wind gusts,endangering the safety of occupants.Using a validated computational fluid dynamics model,this study investigates the potential of various vegetative barriers or shelterbelts in attenuating the high wind speeds encountered in such spaces and the impact on wind and thermal comfort.Three skygarden configurations were investigated with and without vegetative barriers,simplified and modelled as porous zones,and their effect was studied on the velocity and temperature profile at the occupants’level.The results indicate that while hedges and trees can offer resistance to airflow,trees provide higher temperature reduction.However,a combination of vegetative and geometrical barriers provides the most optimal condition in the skygarden.The study has identified the importance of assessing wind attenuation characteristics of tree plantations on highrise skygarden,and the results can be used in designing intervention strategies.Moreover,vegetation can attenuate pollutants and mitigate poor air quality by surface deposition,and future studies should investigate in that direction.
