Numerical Study of Thermal Comfort with the Effects of Canopy Transparency

2014 ◽  
Vol 919-921 ◽  
pp. 1677-1680
Author(s):  
Choul Woong Kwon ◽  
Sung Woo Shin
Keyword(s):  
Thermal Comfort ◽  
Urban Areas ◽  
Thermal Environment ◽  
Numerical Study ◽  
Complex Surface ◽  
Outdoor Thermal Comfort ◽  
Thermal Indices ◽  
Physiological Equivalent Temperature ◽  
Thermal Index ◽  
Radiation Fluxes

Several complex thermal indices (e.g. PMV and PET) were developed in the last decades to describe the quantify the thermal environment of humans and the energy fluxes between body and environment. Compared to open spaces the complex surface structure of urban areas creates an environment with special microclimatic characteristics, which have a dominant effect on the energy balance of the human body. In this study, outdoor thermal comfort conditions are examined through numerical model with different transparency ratios in canopy. The intensity of radiation fluxes is dependent on several factors, such as orientation, size and transparency of canopy. Special emphasis is given to the human-biometeorological assessment of the microclimate of building element (canopy) through the application of the thermal index PET (Physiological Equivalent Temperature). The analysis is carried out by the utilization of Ecotect and RayMan software.

scholarly journals Forecasting of outdoor thermal comfort index in urban open spaces: The Nis fortress case study

2016 ◽  
Vol 20 (suppl. 5) ◽  
pp. 1531-1539 ◽  
Author(s):  
Ivana Bogdanovic-Protic ◽  
Ana Vukadinovic ◽  
Jasmina Radosavljevic ◽  
Meysam Alizamirc ◽  
Mihajlo Mitkovic
Keyword(s):  
Thermal Comfort ◽  
Extreme Learning Machine ◽  
Computational Models ◽  
Thermal Environment ◽  
Outdoor Thermal Comfort ◽  
Special Importance ◽  
Equivalent Temperature ◽  
Machine Model ◽  
Physiological Equivalent Temperature ◽  
Learning Machine

Outdoor thermal environment is affected by variables like air temperature, wind velocity, humidity, temperature of the radiant surfaces, and solar radiation, which can be expressed by a single number - the thermal index. Since these variables are subject to annual and diurnal variations, prediction of thermal comfort is of special importance for people to plan their outdoor activities. The purpose of this research was to develop and apply the extreme learning machine for forecasting physiological equivalent temperature values. The results of the extreme learning machine model were compared with genetic programming and artificial neural network. The reliability of the computational models was accessed based on simulation results and using several statistical indicators. According to obtained results, it can be concluded that extreme learning machine can be utilized effectively in short term forecasting of physiological equivalent temperature.

scholarly journals Outdoor Thermal Comfort of Urban Park—A Case Study

2020 ◽  
Vol 12 (5) ◽  
pp. 1961 ◽  
Author(s):  
Lili Zhang ◽  
Dong Wei ◽  
Yuyao Hou ◽  
Junfei Du ◽  
Zu’an Liu ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Urban Areas ◽  
Thermal Sensation ◽  
Urban Parks ◽  
Living Environment ◽  
Outdoor Thermal Comfort ◽  
Climate Index ◽  
Urban Residents ◽  
Physiological Equivalent Temperature ◽  
Different Types

Urban parks are an important component of urban public green space and a public place where a large number of urban residents choose to conduct outdoor activities. An important factor attracting people to visit and stay in urban parks is its outdoor thermal comfort, which is also an important criterion for evaluating the liability of the urban environment. In this study, through field meteorological monitoring and a questionnaire survey, outdoor thermal comfort of different types of landscape space in urban parks in Chengdu, China was studied in winter and summer. Result indicated that (1) different types of landscape spaces have different thermal comforts, (2) air temperature is the most important factor affecting outdoor thermal comfort; (3) because the thermal sensation judgment of outdoor thermal comfort research in Chengdu area, an ASHRAE seven-sites scale can be used; (4) the neutral temperature ranges of Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) in Chengdu in winter and summer were obtained through research; (5) and UTCI is the best index for evaluating outdoor thermal comfort in Chengdu. These findings provide theoretical benchmarks and technical references for urban planners and landscape designers to optimize outdoor thermal comfort in urban areas to establish a more comfortable and healthy living environment for urban residents.

scholarly journals Outdoor Thermal Comfort Analysis in a Cold Continental Climate: The Case of a Pedestrian-Only Street in Downtown Toronto

2021 ◽  
Author(s):  
Christopher Marleau
Keyword(s):  
Thermal Comfort ◽  
Thermal Sensation ◽  
Computer Software ◽  
Thermal Conditions ◽  
Field Investigation ◽  
Outdoor Thermal Comfort ◽  
Thermal Indices ◽  
Physiological Equivalent Temperature ◽  
Weather Patterns ◽  
Continental Climate

Increased interest in urban thermal comfort has emerged in recent years with unpredictable weather patterns and unprecedented temperature extremes around the world. Urban modelling computer software can help with understanding interactions between built environment and microclimates. However, results of simulations can be difficult to interpret if acceptable thermal conditions for a location are unknown. Using a compound approach of field investigation and microclimate modelling for a pedestrian-only street in Toronto, Canada, this study investigates urban outdoor thermal comfort (OTC) in a cold continental climate. Four thermal indices were used to analyze field data and the results were compared with OTC research conducted in other climates. In this study, the Physiological Equivalent Temperature (PET) provided the strongest annual correlation with the pedestrian thermal sensation votes. A PET comfort range between 9°C and 24°C was found. Survey results were then used to interpret the simulated effect of urban vegetation within the case study microclimate during a summer scenario.

scholarly journals A Seasonal Field Investigation to Perceive Outdoor Thermal Comfort and Thermal Adaption at Malacca Tourist Area- A Pilot Test

2021 ◽  
Author(s):  
Golnoosh Manteghi
Keyword(s):  
Thermal Comfort ◽  
Seasonal Variations ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Outdoor Thermal Comfort ◽  
Utilization Rate ◽  
Equivalent Temperature ◽  
Physiological Equivalent Temperature ◽  
Outdoor Spaces ◽  
Different Seasons

Season plays a key role in the development of outdoor spaces for pedestrians in hot humid cities. This research studies the influence of seasonal variations on pedestrian thermal comfort on the pedestrian level by means of meteorology and field observations of selected footpaths in the major tourist area of Malacca. This experiment was carried out on selected clear calm days indicative of each season during the development of a research project, and hourly meteorological transects from 10:00 am to 6:00 pm and questioned 200 respondents on their thermal awareness, comfort, and preferences were conducted. Adaptation, thermal comfort vote, thermal preference, age, season and hour of the day were significant non-meteorological factors, apart from meteorological information. The findings of analyzes showed that the thermal experience and expectation existed and in different seasons people changed perceptions for the outside thermal environment. Almost 80% local tourist and 55 % international tourist was accepted Physiologically Equivalent Temperature (PET) range affected by the local climate and thermal adaptation. The subjective thermal sensation on physiological equivalent temperature generated an acceptable physiological equivalent temperature of 32.6°C to 36.8°C based on the seasonal variations for Malacca tourist zone in Malaysia. These findings shed light on the optimal design of outdoor spaces for increasing the utilization rate. The seasonal variation must be taken into account so that the outdoor landscape design provides more opportunities for different seasons to communicate with the atmosphere and so enhance thermal comfort and utilization.

scholarly journals Post-occupancy evaluation of outdoor thermal comfort in hot arid zone

2020 ◽  
Author(s):  
Rawan Shawesh ◽  
Mady Mohamed
Keyword(s):  
Thermal Comfort ◽  
Arid Zone ◽  
Objective Assessment ◽  
Subjective Assessment ◽  
Outdoor Thermal Comfort ◽  
Thermal Indices ◽  
Physiological Equivalent Temperature ◽  
Post Occupancy Evaluation ◽  
Physical Measurements ◽  
Globe Temperature

Abstract Human comfort and healthy environments lie at the core of every debate about outdoor spaces nowadays. Thermal comfort is a vital concern for planners and designers in order to produce a healthy and thermally comfortable environment, since the influence of different climates and user groups has been found to greatly alter the range of responses for thermal comfort calculations. This requires Post-Occupancy Evaluation (POE) with an integration of the appropriate outdoor thermal comfort (OTC) index. This paper presents the results of a detailed assessment for the OTC in hot arid zone (HAZ) using the most suitable thermal index. A case study was selected from Effat Campus, Jeddah, Saudi Arabia, to represent the HAZ. Subjective assessment employed the physiological equivalent temperature (PET) and the predictive mean vote (PMV) thermal indices in analysing the results of online and self-directed questionnaires while objective assessment employed a hand-held anemometer that was used to measure wind speed, whereas the wet bulb globe temperature (WBGT) SD Card Logger with a black globe thermometer 75 mm in diameter and emissivity of 0.95 was used to measure the globe temperature. The physical measurements were later used to calculate the mean radiant temperature (MRT) and consequently the PET index using RayMan Software. The results confirmed the significance of the shading strategy on OTC. The study revealed that there is no percentage as shading is permitting people to use the space; otherwise, in hot arid zone, the space would be completely unusable under the sun while the PET is more suitable than the PMV index.

scholarly journals Outdoor Thermal Comfort Analysis in a Cold Continental Climate: The Case of a Pedestrian-Only Street in Downtown Toronto

2021 ◽  
Author(s):  
Christopher Marleau
Keyword(s):  
Thermal Comfort ◽  
Thermal Sensation ◽  
Computer Software ◽  
Thermal Conditions ◽  
Field Investigation ◽  
Outdoor Thermal Comfort ◽  
Thermal Indices ◽  
Physiological Equivalent Temperature ◽  
Weather Patterns ◽  
Continental Climate

Increased interest in urban thermal comfort has emerged in recent years with unpredictable weather patterns and unprecedented temperature extremes around the world. Urban modelling computer software can help with understanding interactions between built environment and microclimates. However, results of simulations can be difficult to interpret if acceptable thermal conditions for a location are unknown. Using a compound approach of field investigation and microclimate modelling for a pedestrian-only street in Toronto, Canada, this study investigates urban outdoor thermal comfort (OTC) in a cold continental climate. Four thermal indices were used to analyze field data and the results were compared with OTC research conducted in other climates. In this study, the Physiological Equivalent Temperature (PET) provided the strongest annual correlation with the pedestrian thermal sensation votes. A PET comfort range between 9°C and 24°C was found. Survey results were then used to interpret the simulated effect of urban vegetation within the case study microclimate during a summer scenario.

A Pilot Test to Analyse the Differences of Pedestrian Thermal Comfort Between Locals and Internationals in Malacca Heritage Site

2020 ◽  
Vol 11 (2) ◽  
pp. 326-341
Author(s):  
Golnoosh Manteghi ◽  
Tasneem Mostofa ◽  
Hasanuddin Bin Lamit
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Outdoor Thermal Comfort ◽  
Pilot Test ◽  
Physiological Equivalent Temperature ◽  
Demographic Groups ◽  
Human Thermal Comfort ◽  
Heritage Site ◽  
Outdoor Spaces

The present study aims to establish a correlation between the physiological equivalent temperature (PET) and subjective thermal sensation in the Tropics, assessing their impact on local as well as international pedestrians. The pilot test was conducted in six scenarios in the Malacca region of Malaysia. The RayMan model calculated the PET, which is further used to synthetically evaluate the thermal environment for six scenarios, each with a different river width and pavement material. The independent t-test and regression analysis determined the correlation between human thermal comfort acceptability and the thermal environment indices of outdoor spaces. Most of the outdoor thermal comfort assessments have been carried out focusing on local urban residents, while the same assessments on tourists are limited. This research provides necessary insight into the perception of outdoor microclimatic conditions in the Malacca heritage area and also identifies the perception on a few important psychological factors of these two demographic groups. An awareness of such issues would be fruitful for architects, planners and urban designers engaged in the process of designing and planning tourist destinations.

Landscape Attributes, Microclimate and Thermal Comfort of an Urban Square in Moderate and Dry Climate

2012 ◽  
Vol 610-613 ◽  
pp. 3780-3784 ◽  
Author(s):  
Shahab Kariminia ◽  
Sabarinah Sh Ahmad ◽  
Ibrahim Norhati
Keyword(s):  
Thermal Comfort ◽  
Urban Space ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Positive Influence ◽  
Outdoor Thermal Comfort ◽  
Physiological Equivalent Temperature ◽  
Public Square ◽  
Pet Index ◽  
Landscape Attributes

Recent rapid urban growth in major cities highlights the role of public squares, where their success can be gauged by its frequency of use and the outdoor thermal conditions. Despite the growing number of studies on outdoor thermal comfort in temperate and dry climate, those done in the Middle East are still limited. This paper examines the effects of landscape attributes on microclimatic conditions and outdoor thermal comfort based on the physiological equivalent temperature (PET) index in Esfahan, Iran. The thermal comfort prediction and correlation between thermal environment and the use of urban space were also explored. Two fieldwork studies were conducted through simultaneous environmental measurement and questionnaire survey in winter and summer at a public square in Esfahan. The obtained data became the basis for Tmrt (mean radiant temperature) and PET estimations, supported by RayMan model. The thermal environment was investigated with different landscape attributes. The derived thermal acceptable range was found to be considerably wider that those reported in previous studies. A strong correlation was confirmed between the thermal conditions and the use of outdoor spaces. The findings demonstrated the strong positive influence of air velocity and evaporative effect of water on thermal comfort. The findings contribute toward suitable design of public squares in climates similar to Esfahan.

scholarly journals Biomimicry-Based Strategies for Urban Heat Island Mitigation: A Numerical Case Study under Tropical Climate

Biomimetics ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 48
Author(s):  
Kevin Araque ◽  
Paola Palacios ◽  
Dafni Mora ◽  
Miguel Chen Austin
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Urban Areas ◽  
Outdoor Thermal Comfort ◽  
Base Case ◽  
Heat Island ◽  
Urban Heat ◽  
Historical Heritage ◽  
Pet Index ◽  
Radiant Temperature

In recent years, demographic growth has caused cities to expand their urban areas, increasing the risk of overheating, creating insurmountable microclimatic conditions within the urban area, which is why studies have been carried out on the urban heat island effect (UHI) and its mitigation. Therefore, this research aims to evaluate the cooling potential in the application of strategies based on biomimicry for the microclimate in a historical heritage city of Panama. For this, three case studies (base case, case 1, and case 2) of outdoor thermal comfort were evaluated, in which the Envi-met software was used to emulate and evaluate the thermal performance of these strategies during March (highest temperature month) and October (rainier month). The strategies used were extracted from the contrast of zebra skin, human skin, evaporative cooling, and ant skin. The results showed a reduction of 2.8 °C in the air temperature at 11:00, the radiant temperature decreased by 2.2 °C, and the PET index managed to reduce the thermal comfort indicator among its categories. The importance of thinking based on biomimicry in sustainable strategies is concluded; although significant changes were obtained, high risks of discomfort persist due to the layout and proximity of the building.

Implications of Building Material Choice on Outdoor Microclimate for Sustainable Built Environment

2015 ◽  
Vol 650 ◽  
pp. 82-90 ◽  
Author(s):  
D. Kannamma ◽  
A. Meenatchi Sundaram
Keyword(s):  
Thermal Comfort ◽  
Building Material ◽  
Building Materials ◽  
Climatic Factors ◽  
Outdoor Environment ◽  
Outdoor Thermal Comfort ◽  
Physical Factors ◽  
Physiological Equivalent Temperature ◽  
Material Choice ◽  
The Impact

The climatic conditions in a man-made urban environment may differ appreciably from those in the surrounding natural or rural environs.... each urban man-made buildings, roads, parking area, factories......creates around and above it a modified climate with which it interacts [1].Outdoor thermal comfort has gained importance in thermal comfort studies especially in tropical countries. In country like India, culturally the activities are spread both indoors and outdoors. Therefore the need for ambient outdoor environment gains importance. As there are many factors that contribute to outdoor thermal comfort (climatic factors and physical factors), this study aims in analyzing the impact of building material contribution, in an institutional courtyard. In order to understand the thermal contribution of various building materials and to suggest material choice to designers, ENVIMET is used for simulation purpose. The outdoor thermal comfort index employed in this study is PET (Physiological Equivalent Temperature), calibrated using RAYMAN.

Sign in / Sign up

Export Citation Format

Share Document