Urban Heat Island(UHI)effects are exacerbated by the expansion of impervious surfaces and loss of vegetation in urban centers,leading to elevated air and surface temperatures and reduced thermal comfort.Urban trees,th...Urban Heat Island(UHI)effects are exacerbated by the expansion of impervious surfaces and loss of vegetation in urban centers,leading to elevated air and surface temperatures and reduced thermal comfort.Urban trees,through shading and evapotranspiration,are among the most effective Nature-based Solutions(NbS)for passive cooling.This study assesses the cooling potential of selected tree species by analyzing their morphological and physiological traits using a combination of ENVI-met microclimate simulations and multiple regression modeling.A total of 15 urban tree species were selected from the literature and analyzed based on their dependency of their cooling efficacy.Later validated in urban setting by Envi-met simulations.Key traits,such as Leaf Area Index(LAI),canopy density,transpiration rate,tree height,rooting depth,and water availability,were analyzed.Multiple linear regression analysis was conducted to quantify the contribution of each trait to ambient temperature reduction.Results revealed that LAI(R^(2)=0.76,p<0.001)and transpiration rate(R^(2)=0.71,p<0.001)were the most significant predictors of daytime cooling,while canopy openness and tree height were more strongly correlated with nighttime heat dissipation.High-performing species,such as Ficus benghalensis,Azadirachta indica,and Samanea saman,demonstrated a maximum temperature reduction of 2.5-4.2℃,especially in compact,low-rise,and mid-rise zones.The study provides a quantitative trait-based framework for tree selection in urban greening initiatives and offers evidence to guide landscape planning and UHI mitigation strategies through scientifically informed plantation design.展开更多
In this paper, three types of green spaces in Xijing Community in Shijingshan District of Beijing were selected for as the measuring points, the HOBO portable weather station was used to monitor the microclimate envir...In this paper, three types of green spaces in Xijing Community in Shijingshan District of Beijing were selected for as the measuring points, the HOBO portable weather station was used to monitor the microclimate environmental changes in the same period and summarize the data of microclimate factors. The effectiveness of the simulation was verified by comparing the measured data with the simulated data obtained through ENVI-met. And strategies for microclimate adaptive design in residential areas were proposed according to the microclimate environmental characteristics of several green spaces.展开更多
With the continuous advancement of urbanization,how to improve the microclimate of urban public space and enhance ecological sustainability has become an important research direction of landscape architecture in the f...With the continuous advancement of urbanization,how to improve the microclimate of urban public space and enhance ecological sustainability has become an important research direction of landscape architecture in the future.Based on Envi-met,taking Min’an Community of Beijing City as research object,three-dimensional space model is established according to its architectural pattern,nature of underlying surface and green space pattern,and the change law of microclimate in the research zone under the existing spatial pattern and the influence mechanism of various factors are analyzed.PMV is taken as evaluation index of thermal comfort,and corresponding improvement measures are proposed,and improvement effect is simulated and improved.展开更多
Reasonable greening design can effectively alleviate campus heat environment issues.This study uses the ENVI-met numerical model,along with in-situ observations and simulations,to analyze the thermal environment under...Reasonable greening design can effectively alleviate campus heat environment issues.This study uses the ENVI-met numerical model,along with in-situ observations and simulations,to analyze the thermal environment under three different greening schemes in typical areas of the Guangzhou University campus.The results indicate that the outdoor thermal environment is significantly influenced by the underlying surface materials and vegetation.The temperature of brick-paved surface is 0.9℃higher than that of natural soil surfaces under tree shade.Numerical simulations further confirm that increasing vegetation coverage effectively reduces outdoor air temperature.When the greening rate increases to 40%,the outdoor average temperature decreases by 0.7℃and relative humidity increases by approximately 4%,while wind speed remains minimal change.The cooling effect of vegetation is found to extend vertically to an altitude of 13 m.As the greening rate increases from 15%to 40%,the Mean Radiant Temperature(MRT)decreases from 50.6℃to 28.9℃,which is lower than the average ambient temperature,indicating improved thermal conditions.The Physiological Equivalent Temperature(PET)decreases from 40.2℃to 30.0℃,with the proportion of the areas classified as″very hot″reducing by 36.8%,significantly improving thermal comfort across most areas.Therefore,changing the ground material and greening landscape design can effectively alter the outdoor wind and thermal environment of the campus,thereby enhancing the thermal comfort for the campus community.展开更多
Indoor microclimate is important for crop production and quality in greenhouse cultivation. This paper focuses on microclimate study based on a computational fluid dynamics （CFD） model of a typical plastic greenhou...Indoor microclimate is important for crop production and quality in greenhouse cultivation. This paper focuses on microclimate study based on a computational fluid dynamics （CFD） model of a typical plastic greenhouse （with a sector shape vertical cross-section） popularly used in central China. A radiation model is added into the CFD model so as to simulate coupling of convective transfers and radiative exchanges at the cover and the roof, instead of using the usual coupling approach based on energy balance. In addition, a fractal permeability model is innovatively adopted in the modeling of the crop canopy. Compared the numerical results with measured experimental data, the model simulation is proved with success. This model then is used to explore the microclimate variable distributions in the greenhouse. It shows that the airflow pattern, temperature and humidity profiles are different from those in a sawtooth Mediterranean- type greenhouse. The study suggests that this deliberately developed CFD model can be served as a useful tool in macroclimate research and greenhouse design investigating.展开更多
To improve the outdoor environment of rural settlement and reduce the energy consumption of rural houses in winterin cold areas,the seriously bad wind environment should been controlled and considered. This paper appl...To improve the outdoor environment of rural settlement and reduce the energy consumption of rural houses in winterin cold areas,the seriously bad wind environment should been controlled and considered. This paper applies the method of numerical simulation to simulate the wind environment of some typical arrangement of building and courtyard in winter,and concludes the optimal building and courtyard arrangement types and strategies. It aims to provide some technical supports for improving the wind environment of rural settlements in cold regions.展开更多
<span style="font-family:Verdana;">Understanding the environment of olive tree cuttings is a key factor in improving these plants’ rooting rate and survival. This study aims to develop </span>&l...<span style="font-family:Verdana;">Understanding the environment of olive tree cuttings is a key factor in improving these plants’ rooting rate and survival. This study aims to develop </span><span style="font-family:Verdana;"> a </span><span style="font-family:Verdana;">three-dimensional (3-D) Computational Fluid Dynamics (CFD) model for</span><span style="font-family:Verdana;"> numerically assessing air temperature and relative humidity in an olive cuttings </span><span style="font-family:Verdana;">greenhouse under Mediterranean climatic conditions. The results are deduced from a steady-state simulation performed with recorded boundary</span><span style="font-family:Verdana;"> conditions at 10:00 am, 12:00 pm, 02:00 pm, 04:00 pm, and 06:00 pm at different obser</span><span style="font-family:Verdana;">vation points. The calculations were validated using experimental data. The </span><span style="font-family:Verdana;">simulation errors of the air temperature were -0.8°C to 4.55°C, </span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">and errors of</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the leaf </span><span style="font-family:Verdana;">temperature were 0.07°C to 2.42°C, for the air relative humidity w</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">as</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> <span style="font-family:Verdana;white-space:normal;">-</span>33.84% to <span style="font-family:Verdana;white-space:normal;">-</span>1.64%</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> and <span style="font-family:Verdana;white-space:normal;">-</span>10.1% to <span style="font-family:Verdana;white-space:normal;">-</span>13.54% for the relative humidity of the leaf air. Contour maps were obtained from the 3-D CFD simulations to evaluate the distribution of humidity and air temperature inside the greenhouse </span><span style="font-family:Verdana;">and the vicinity of the plant canopy. This study suggests that the developed</span><span style="font-family:Verdana;"> 3-D CFD model can be a helpful tool to understand and optimize</span><span style="font-family:Verdana;"> greenhouse operation for better crop quality.</span></span></span></span>展开更多
To achieve fire prevention in heritage buildings,it is crucial to identify,analyse,and assess fire risks prior to fires due to the complexity of fire causes and risk factors influenced by various aspects such as envir...To achieve fire prevention in heritage buildings,it is crucial to identify,analyse,and assess fire risks prior to fires due to the complexity of fire causes and risk factors influenced by various aspects such as environmental factors,building material characteristics,layout and management/maintenance practices.For building-specific fire risk identification,fire process simulation models constructed based on quantifying various fire risk elements are needed.Some studies have found that indoor microclimate has different degrees of influence on the fire development process,but there is a lack of relevant modelling.Taking the Grand Hall of Baoguo Monastery in Ningbo as an example,32 fire operating conditions were simulated using the Fire Dynamics Simulator based on the monitoring environment data collected in the hall.The results revealed that the building structural nodes had higher fire risks,the wind direction significantly affected fire spread in the hall,ambient temperature could influence the fire development rate,smoke was more easily detected at the ceiling,and except for the temperature change(P<0.01),the other indicators did not differ significantly across environmental conditions.Subsequently,a fire detector installation strategy with temperature,CO concentration and smoke detectors as detection indicators was proposed.展开更多
Background:Increasing urbanization as well as global warming requires an investigation of the infuence of diferent construction methods and ground surfaces on the urban heat island efect(UHI efect).The extent of the i...Background:Increasing urbanization as well as global warming requires an investigation of the infuence of diferent construction methods and ground surfaces on the urban heat island efect(UHI efect).The extent of the infuence of the urban structure,the building materials used and their surfaces on the UHI efect can be signifcantly reduced already in the planning phase using a designated OpenFOAM-based solver“uhiSolver”.Results:In the frst part of this research work,it is shown that inner building details and components can be neglected while still obtaining sufciently accurate results.For this purpose,the building model was divided into two layers:a surface layer without mass,where the interaction with radiation takes place,and a component layer,which contains all relevant components and cavities of the building represented with mass-averaged material properties.It has become apparent that the three parameters—albedo,heat capacity and thermal resistance—which have a decisive infuence on the interaction,have diferent efects on the component temperatures and the surface temperatures.In the second part of this research work,dynamic 3D computational fuid dynamics(CFD)simulations are performed with uhiSolver for a residential block in Vienna.Comparing the simulation results with measurement data collected on site,it is shown that the simplifed assumption of homogeneous material data for building bodies provides very good results for the validation case investigated.However,the infuence of the greening measures in the courtyard of the residential block on the air temperature is found to be negligible.Furthermore,it was observed that due to locally higher radiation density,lower air velocities and higher air humidity,the apparent temperature in the courtyard is sometimes perceived to be higher than in the adjacent streets,despite the lower air temperature.Conclusions:Simplifying the modeling process of the uhiSolver software by reducing the model complexity helps to reduce manual work for setting up appropriate boundary conditions of buildings.Compared to market competitors,good results are obtained for the validation case Kandlgasse presented in this research work,despite the simplifcations proposed.Thus,uhiSolver can be used as a robust analytical tool for urban planning.展开更多
文摘Urban Heat Island(UHI)effects are exacerbated by the expansion of impervious surfaces and loss of vegetation in urban centers,leading to elevated air and surface temperatures and reduced thermal comfort.Urban trees,through shading and evapotranspiration,are among the most effective Nature-based Solutions(NbS)for passive cooling.This study assesses the cooling potential of selected tree species by analyzing their morphological and physiological traits using a combination of ENVI-met microclimate simulations and multiple regression modeling.A total of 15 urban tree species were selected from the literature and analyzed based on their dependency of their cooling efficacy.Later validated in urban setting by Envi-met simulations.Key traits,such as Leaf Area Index(LAI),canopy density,transpiration rate,tree height,rooting depth,and water availability,were analyzed.Multiple linear regression analysis was conducted to quantify the contribution of each trait to ambient temperature reduction.Results revealed that LAI(R^(2)=0.76,p<0.001)and transpiration rate(R^(2)=0.71,p<0.001)were the most significant predictors of daytime cooling,while canopy openness and tree height were more strongly correlated with nighttime heat dissipation.High-performing species,such as Ficus benghalensis,Azadirachta indica,and Samanea saman,demonstrated a maximum temperature reduction of 2.5-4.2℃,especially in compact,low-rise,and mid-rise zones.The study provides a quantitative trait-based framework for tree selection in urban greening initiatives and offers evidence to guide landscape planning and UHI mitigation strategies through scientifically informed plantation design.
基金Sponsored by 2018 Beijing Municipal University Academic Human Resources Development—Youth Talent Support Program(PXM2018_014212_000043)North China University of Technology “YuYOU” Talent Training Program
文摘In this paper, three types of green spaces in Xijing Community in Shijingshan District of Beijing were selected for as the measuring points, the HOBO portable weather station was used to monitor the microclimate environmental changes in the same period and summarize the data of microclimate factors. The effectiveness of the simulation was verified by comparing the measured data with the simulated data obtained through ENVI-met. And strategies for microclimate adaptive design in residential areas were proposed according to the microclimate environmental characteristics of several green spaces.
基金Sponsored by National Natural Science Foundation of China(51708004)Yuyou Talent Training Program of North China University of Technology(215051360020XN160/009)+2 种基金Beijing Natural Science Foundation(8202017)Basal Research Fund of North China University of Technology(110052972027/154)2018 Beijing Municipal University Academic Human Resources Development—Youth Talent Support Program(PXM2018014212000043)。
文摘With the continuous advancement of urbanization,how to improve the microclimate of urban public space and enhance ecological sustainability has become an important research direction of landscape architecture in the future.Based on Envi-met,taking Min’an Community of Beijing City as research object,three-dimensional space model is established according to its architectural pattern,nature of underlying surface and green space pattern,and the change law of microclimate in the research zone under the existing spatial pattern and the influence mechanism of various factors are analyzed.PMV is taken as evaluation index of thermal comfort,and corresponding improvement measures are proposed,and improvement effect is simulated and improved.
基金Science and Technology Research Project of Guang-dong Meteorological Bureau(GRMC2022M21)Guangdong Basic and Applied Basic Research Foundation(2023A1515012240)Research Project of Guangzhou Meteor-ological Bureau(M202218)。
文摘Reasonable greening design can effectively alleviate campus heat environment issues.This study uses the ENVI-met numerical model,along with in-situ observations and simulations,to analyze the thermal environment under three different greening schemes in typical areas of the Guangzhou University campus.The results indicate that the outdoor thermal environment is significantly influenced by the underlying surface materials and vegetation.The temperature of brick-paved surface is 0.9℃higher than that of natural soil surfaces under tree shade.Numerical simulations further confirm that increasing vegetation coverage effectively reduces outdoor air temperature.When the greening rate increases to 40%,the outdoor average temperature decreases by 0.7℃and relative humidity increases by approximately 4%,while wind speed remains minimal change.The cooling effect of vegetation is found to extend vertically to an altitude of 13 m.As the greening rate increases from 15%to 40%,the Mean Radiant Temperature(MRT)decreases from 50.6℃to 28.9℃,which is lower than the average ambient temperature,indicating improved thermal conditions.The Physiological Equivalent Temperature(PET)decreases from 40.2℃to 30.0℃,with the proportion of the areas classified as″very hot″reducing by 36.8%,significantly improving thermal comfort across most areas.Therefore,changing the ground material and greening landscape design can effectively alter the outdoor wind and thermal environment of the campus,thereby enhancing the thermal comfort for the campus community.
基金supported by the National Natural Science Foundation of China (50979077)
文摘Indoor microclimate is important for crop production and quality in greenhouse cultivation. This paper focuses on microclimate study based on a computational fluid dynamics （CFD） model of a typical plastic greenhouse （with a sector shape vertical cross-section） popularly used in central China. A radiation model is added into the CFD model so as to simulate coupling of convective transfers and radiative exchanges at the cover and the roof, instead of using the usual coupling approach based on energy balance. In addition, a fractal permeability model is innovatively adopted in the modeling of the crop canopy. Compared the numerical results with measured experimental data, the model simulation is proved with success. This model then is used to explore the microclimate variable distributions in the greenhouse. It shows that the airflow pattern, temperature and humidity profiles are different from those in a sawtooth Mediterranean- type greenhouse. The study suggests that this deliberately developed CFD model can be served as a useful tool in macroclimate research and greenhouse design investigating.
基金Sponsored bythe National Project of Scientific and Technical Supporting Programs Funded by Ministry of Science & Technology of China(Grant No.2013BAJ12B02)the Fundamental Research Funds for the Central Universities(Grant No.HIT.KISTP.201419)
文摘To improve the outdoor environment of rural settlement and reduce the energy consumption of rural houses in winterin cold areas,the seriously bad wind environment should been controlled and considered. This paper applies the method of numerical simulation to simulate the wind environment of some typical arrangement of building and courtyard in winter,and concludes the optimal building and courtyard arrangement types and strategies. It aims to provide some technical supports for improving the wind environment of rural settlements in cold regions.
文摘<span style="font-family:Verdana;">Understanding the environment of olive tree cuttings is a key factor in improving these plants’ rooting rate and survival. This study aims to develop </span><span style="font-family:Verdana;"> a </span><span style="font-family:Verdana;">three-dimensional (3-D) Computational Fluid Dynamics (CFD) model for</span><span style="font-family:Verdana;"> numerically assessing air temperature and relative humidity in an olive cuttings </span><span style="font-family:Verdana;">greenhouse under Mediterranean climatic conditions. The results are deduced from a steady-state simulation performed with recorded boundary</span><span style="font-family:Verdana;"> conditions at 10:00 am, 12:00 pm, 02:00 pm, 04:00 pm, and 06:00 pm at different obser</span><span style="font-family:Verdana;">vation points. The calculations were validated using experimental data. The </span><span style="font-family:Verdana;">simulation errors of the air temperature were -0.8°C to 4.55°C, </span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">and errors of</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the leaf </span><span style="font-family:Verdana;">temperature were 0.07°C to 2.42°C, for the air relative humidity w</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">as</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> <span style="font-family:Verdana;white-space:normal;">-</span>33.84% to <span style="font-family:Verdana;white-space:normal;">-</span>1.64%</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> and <span style="font-family:Verdana;white-space:normal;">-</span>10.1% to <span style="font-family:Verdana;white-space:normal;">-</span>13.54% for the relative humidity of the leaf air. Contour maps were obtained from the 3-D CFD simulations to evaluate the distribution of humidity and air temperature inside the greenhouse </span><span style="font-family:Verdana;">and the vicinity of the plant canopy. This study suggests that the developed</span><span style="font-family:Verdana;"> 3-D CFD model can be a helpful tool to understand and optimize</span><span style="font-family:Verdana;"> greenhouse operation for better crop quality.</span></span></span></span>
基金supported by the foundation of Jiangsu Province Engineering Research Center of Construction Carbon Neutral Technology(No.JZTZH 2022-0101)。
文摘To achieve fire prevention in heritage buildings,it is crucial to identify,analyse,and assess fire risks prior to fires due to the complexity of fire causes and risk factors influenced by various aspects such as environmental factors,building material characteristics,layout and management/maintenance practices.For building-specific fire risk identification,fire process simulation models constructed based on quantifying various fire risk elements are needed.Some studies have found that indoor microclimate has different degrees of influence on the fire development process,but there is a lack of relevant modelling.Taking the Grand Hall of Baoguo Monastery in Ningbo as an example,32 fire operating conditions were simulated using the Fire Dynamics Simulator based on the monitoring environment data collected in the hall.The results revealed that the building structural nodes had higher fire risks,the wind direction significantly affected fire spread in the hall,ambient temperature could influence the fire development rate,smoke was more easily detected at the ceiling,and except for the temperature change(P<0.01),the other indicators did not differ significantly across environmental conditions.Subsequently,a fire detector installation strategy with temperature,CO concentration and smoke detectors as detection indicators was proposed.
基金funded byÖsterreichische Forschungsförderungsgesellschaft FFG—feasibility study,Grant number 873045.
文摘Background:Increasing urbanization as well as global warming requires an investigation of the infuence of diferent construction methods and ground surfaces on the urban heat island efect(UHI efect).The extent of the infuence of the urban structure,the building materials used and their surfaces on the UHI efect can be signifcantly reduced already in the planning phase using a designated OpenFOAM-based solver“uhiSolver”.Results:In the frst part of this research work,it is shown that inner building details and components can be neglected while still obtaining sufciently accurate results.For this purpose,the building model was divided into two layers:a surface layer without mass,where the interaction with radiation takes place,and a component layer,which contains all relevant components and cavities of the building represented with mass-averaged material properties.It has become apparent that the three parameters—albedo,heat capacity and thermal resistance—which have a decisive infuence on the interaction,have diferent efects on the component temperatures and the surface temperatures.In the second part of this research work,dynamic 3D computational fuid dynamics(CFD)simulations are performed with uhiSolver for a residential block in Vienna.Comparing the simulation results with measurement data collected on site,it is shown that the simplifed assumption of homogeneous material data for building bodies provides very good results for the validation case investigated.However,the infuence of the greening measures in the courtyard of the residential block on the air temperature is found to be negligible.Furthermore,it was observed that due to locally higher radiation density,lower air velocities and higher air humidity,the apparent temperature in the courtyard is sometimes perceived to be higher than in the adjacent streets,despite the lower air temperature.Conclusions:Simplifying the modeling process of the uhiSolver software by reducing the model complexity helps to reduce manual work for setting up appropriate boundary conditions of buildings.Compared to market competitors,good results are obtained for the validation case Kandlgasse presented in this research work,despite the simplifcations proposed.Thus,uhiSolver can be used as a robust analytical tool for urban planning.
