Determination of acceptable thermal range in outdoor built environments by various methods

2016 ◽  
Vol 5 (4) ◽  
pp. 352-371 ◽  
Author(s):  
Salman Shooshtarian ◽  
Ian Ridley
Keyword(s):  
Comparative Analysis ◽  
Thermal Comfort ◽  
Thermal Conditions ◽  
Outdoor Thermal Comfort ◽  
Built Environments ◽  
Direct Measure ◽  
Thermal Perception ◽  
Content Type ◽  
Thermal Range ◽  
Indirect Measures

Purpose Assessment of outdoor thermal perception in urban spaces is of particular importance due to its financial, social and ecological consequences. Thermal perception includes four elements: thermal sensation votes (TSV), thermal preference (Tpref), overall thermal comfort (Tc) and thermal acceptability (Taccept). Thermal acceptability can offer a benchmark that specifies the acceptable thermal range (ATR), which is useful for urban planners, designers, and bio-meteorologists. ATR, however, can be defined either using direct or indirect measures. The purpose of this paper is to investigate the validity of the indirect measures of ATR, which are most commonly used in outdoor thermal comfort assessments. Design/methodology/approach This study was conducted in the context of Melbourne, which has an oceanic temperate climate (Cfb). Three sites forming RMIT University City Campus (RUCC) were selected as the case studies, which were located in the heart of Melbourne Central Business District. A field survey was conducted in RUCC during three seasons, from November 2014 (Spring) to May 2015 (Autumn), which consisted of concurrent field measurements and questionnaire surveys from 9:00 a.m. to 5:00 p.m. Findings In total, 1,059 valid questionnaires were collected from the three sites of RUCC. The results of comparative analysis between the different measures of ATR determination showed that the various elements of thermal perceptions expressed the users’ thermal judgements in different ways. Therefore, it was found that the instruction recommended by the thermal comfort standards on the definition of ATR failed to provide an appropriate estimation of ATR for outdoor built environments. The ATR, defined using TSV, therefore, was revised by the direct measure of thermal acceptability. The resulting range showed broader limits in acceptable thermal conditions in RUCC outdoor spaces users. Lastly, the results suggest that in the absence of directly measured acceptability of thermal conditions in field surveys, overall comfort is the most appropriate indirect measure to use. Originality/value Some indoor thermal comfort studies have used the alternatives for defining ATR. However, as the applicability of these four methods is yet to be fully explored in outdoor conditions with large weather variations, it is valuable to conduct a comparative analysis among these methods. This study also intended to understand the dynamics of comfort range under non-steady and non-uniform outdoor conditions. The resultant outcome has provided information on the relationship between different measures of thermal perceptions. Ultimately, this research aimed to explore the extent to which the indirect measures of acceptability are considered as a reliable source of information compared to the direct measure.

Some evidence of a time-varying thermal perception

2021 ◽  
pp. 1420326X2110345
Author(s):  
Marika Vellei ◽  
William O’Brien ◽  
Simon Martinez ◽  
Jérôme Le Dréau
Keyword(s):  
Thermal Comfort ◽  
Energy Savings ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Time Of Day ◽  
Time Varying ◽  
Thermal Perception ◽  
Indoor Thermal Environment ◽  
Human Circadian Rhythm ◽  
Comfort Criteria

Recent research suggests that a time-varying indoor thermal environment can lead to energy savings and contribute to boost buildings' energy flexibility. However, thermal comfort standardization has so far considered thermal comfort criteria as constant throughout the day. In general, very little attention has been given to the ‘ time of day' variable in the context of thermal comfort research. In this paper, we show some evidence of a time-varying thermal perception by using: (1) data from about 10,000 connected Canadian thermostats made available as part of the ‘ Donate Your Data' dataset and (2) about 22,000 samples of complete (objective + ‘ right-here-right-now' subjective) thermal comfort field data from the ASHRAE I and SCATs datasets. We observe that occupants prefer colder thermal conditions at 14:00 and progressively warmer ones in the rest of the day, indistinctively in the morning and evening. Neutral temperature differences between 08:00 and 14:00 and 14:00 and 20:00 are estimated to be of the order of 2°C. We hypothesize that the human circadian rhythm is the cause of this difference. Nevertheless, the results of this study are only based on observational data. Thermal comfort experiments in controlled environmental chambers are required to confirm these findings and to better elucidate the effects of light and circadian timing and their interaction on thermal perception.

scholarly journals Thermal Perception in the Mediterranean Area: Comparing the Mediterranean Outdoor Comfort Index (MOCI) to Other Outdoor Thermal Comfort Indices

Energies ◽  
2016 ◽  
Vol 9 (7) ◽  
pp. 550 ◽  
Author(s):  
Iacopo Golasi ◽  
Ferdinando Salata ◽  
Emanuele de Lieto Vollaro ◽  
Massimo Coppi ◽  
Andrea de Lieto Vollaro
Keyword(s):  
Thermal Comfort ◽  
Mediterranean Area ◽  
Outdoor Thermal Comfort ◽  
Thermal Perception ◽  
Comfort Index ◽  
Outdoor Comfort ◽  
The Mediterranean ◽  
Comfort Indices

Thermal comfort prediction by applying supervised machine learning in green sidewalks of Tehran

2020 ◽  
Vol 9 (4) ◽  
pp. 361-374
Author(s):  
Nasim Eslamirad ◽  
Soheil Malekpour Kolbadinejad ◽  
Mohammadjavad Mahdavinejad ◽  
Mohammad Mehranrad
Keyword(s):  
Machine Learning ◽  
Thermal Comfort ◽  
Urban Design ◽  
Energy Modeling ◽  
Supervised Machine Learning ◽  
Outdoor Thermal Comfort ◽  
Social Implications ◽  
Design Strategies ◽  
Content Type ◽  
The Future

PurposeThis research aims to introduce a new methodology for integration between urban design strategies and supervised machine learning (SML) method – by applying both energy engineering modeling (evaluating phase) for the existing green sidewalks and statistical energy modeling (predicting phase) for the new ones – to offer algorithms that help to catch the optimum morphology of green sidewalks, in case of high quality of the outdoor thermal comfort and less errors in results.Design/methodology/approachThe tools of the study are the way of processing by SML, predicting the future based on the past. Machine learning is benefited from Python advantages. The structure of the study consisted of two main parts, as the majority of the similar studies follow: engineering energy modeling and statistical energy modeling. According to the concept of the study, at first, from 2268 models, some are randomly selected, simulated and sensitively analyzed by ENVI-met. Furthermore, the Envi-met output as the quantity of thermal comfort – predicted mean vote (PMV) and weather items are inputs of Python. Then, the formed data set is processed by SML, to reach the final reliable predicted output.FindingsThe process of SML leads the study to find thermal comfort of current models and other similar sidewalks. The results are evaluated by both PMV mathematical model and SML error evaluation functions. The results confirm that the average of the occurred error is about 1%. Then the method of study is reliable to apply in the variety of similar fields. Finding of this study can be helpful in perspective of the sustainable architecture strategies in the buildings and urban scales, to determine, monitor and control energy-based behaviors (thermal comfort, heating, cooling, lighting and ventilation) in operational phase of the systems (existed elements in buildings, and constructions) and the planning and designing phase of the future built cases – all over their life spans.Research limitations/implicationsLimitations of the study are related to the study variables and alternatives that are notable impact on the findings. Furthermore, the most trustable input data will result in the more accuracy in output. Then modeling and simulation processes are most significant part of the research to reach the exact results in the final step.Practical implicationsFinding of the study can be helpful in urban design strategies. By finding outdoor thermal comfort that resulted from machine learning method, urban and landscape designers, policymakers and architects are able to estimate the features of their designs in air quality and urban health and can be sure in catching design goals in case of thermal comfort in urban atmosphere.Social implicationsBy 2030, cities are delved as living spaces for about three out of five people. As green infrastructures influence in moderating the cities’ climate, the relationship between green spaces and habitants’ thermal comfort is deduced. Although the strategies to outside thermal comfort improvement, by design methods and applicants, are not new subject to discuss, applying machines that may be common in predicting results can be called as a new insight in applying more effective design strategies and in urban environment’s comfort preparation. Then study’s footprint in social implications stems in learning from the previous projects and developing more efficient strategies to prepare cities as the more comfortable and healthy places to live, with the more efficient models and consuming money and time.Originality/valueThe study achievements are expected to be applied not only in Tehran but also in other climate zones as the pattern in more eco-city design strategies. Although some similar studies are done in different majors, the concept of study is new vision in urban studies.

scholarly journals How do paving and planting strategies affect microclimate conditions and thermal comfort in apartment complexes?

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ga Yoon Choi ◽  
Hwan Sung Kim ◽  
Hyungkyoo Kim ◽  
Jae Seung Lee
Keyword(s):  
Thermal Comfort ◽  
Green Infrastructure ◽  
Thermal Conditions ◽  
High Density ◽  
Landscape Elements ◽  
Near Surface ◽  
Content Type ◽  
Coniferous Trees ◽  
Comfort Levels ◽  
Microclimate Conditions

Purpose In cities with high density, heat is often trapped between buildings which increases the frequency and intensity of heat events. Researchers have focused on developing strategies to mitigate the negative impacts of heat in cities. Adopting green infrastructure and cooling pavements are some of the many ways to promote thermal comfort against heat. The purpose of this study is to improve microclimate conditions and thermal comfort levels in high-density living conditions in Seoul, South Korea. Design/methodology/approach This study compares six design alternatives of an apartment complex with different paving and planting systems. It also examines the thermal outcome of the alternatives under normal and extreme heat conditions to suggest strategies to secure acceptable thermal comfort levels for the inhabitants. Each alternative is analyzed using ENVI-met, a software program that simulates microclimate conditions and thermal comfort features based on relationships among buildings, vegetation and pavements. Findings The results indicate that grass paving was more effective than stone paving in lowering air temperature and improving thermal comfort at the near-surface level. Coniferous trees were found to be more effective than broadleaf trees in reducing temperature. Thermal comfort levels were most improved when coniferous trees were planted in paired settings. Practical implications Landscape elements show promise for the improvement of thermal conditions because it is much easier to redesign landscape elements, such as paving or planting, than to change fixed urban elements like buildings and roads. The results identified the potential of landscape design for improving microclimate and thermal comfort in urban residential complexes. Originality/value The results contribute to the literature by examining the effect of tree species and layout on thermal comfort levels, which has been rarely investigated in previous studies.

Shading Effect on Outdoor Thermal Comfort in High-Density City a Case Based Study of Beijing

2014 ◽  
Vol 1065-1069 ◽  
pp. 2927-2930 ◽  
Author(s):  
Bai Chuan Ma ◽  
Qi Sang ◽  
Ji Feng Gou
Keyword(s):  
Thermal Comfort ◽  
Field Experiments ◽  
Meteorological Data ◽  
Thermal Conditions ◽  
Central Business District ◽  
Outdoor Thermal Comfort ◽  
View Factor ◽  
Thermal Environments ◽  
Sky View Factor ◽  
Business District

Shading provided by buildings affects outdoor thermal environments and, therefore, influences the long-term thermal comfort of people in outdoor spaces. This study conducted several field experiments to analyze the outdoor thermal conditions on urban streets in central business district (CBD) of Beijing. The RayMan model was utilized for calculating Sky view factor (SVF) and outdoor thermal comfort using meteorological data of one year period. Analytical results indicate that slightly shaded areas (SVF > 0.5) typically have highly frequent hot conditions during summer, particularly at noon; however, highly shaded locations (SVF < 0.3) generally reduce the intra-urban air temperature in winter; moderately shaded areas (0.3 < SVF < 0.5) show the advantage for balancing the hot conditions in summer and cold conditions in winter throughout whole year. Sky view factor can be used as a comprehensive and practical urban planning index at local scale, i.e. urban canyon street and residential estate. It provides a novelty method on scientific planning and sustainable development of city.

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 Application and performance of Kestrel sensors for assessing thermal comfort in outdoor built environments

2021 ◽  
Author(s):  
Lisette Klok ◽  
Erica Caverzam Barbosa ◽  
Luc van Zandbrink ◽  
Jeroen Kluck
Keyword(s):  
Decision Making ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Urban Spaces ◽  
Outdoor Thermal Comfort ◽  
Simple Type ◽  
Built Environments ◽  
The Sun ◽  
Physiological Equivalent Temperature ◽  
Air Temperatures

&lt;p&gt;In face of climate change and urbanization, the need for thermally comfortable outdoor urban spaces is increasing. In the design of the thermally comfortable urban spaces and decision making about interventions that enhance thermal comfort, scientists and professionals that work for cities use meteorological measurements and models. These measurements can be done by professional and accurate meteorological sensors, but also by simpler mobile instruments such as the easy-to-use Kestrel weather meters. In using these simple type of sensors, it is important to know what the performance of these sensors is for outdoor thermal comfort assessments and how they can be used by scientists and professionals in decision making about urban designs that enhance thermal comfort.&lt;/p&gt;&lt;p&gt;To answer these questions, we carried out three experiments in the summer of 2020 in Amsterdam, in which we tested the 11 Kestrel 5400 heat stress sensors and assessed the performance of this equipment for thermal comfort studies. We concluded that Kestrel sensors can be used very well for assessing differences in air temperature and PET (Physiological Equivalent Temperature) between outdoor built environments. For both air temperature and PET, the RMSE between the 11 Kestrel sensors was 0.5 &amp;#176;C maximum when measuring the same conditions. However, Kestrel sensors that were placed in the sun without a wind vane mounted to the equipment showed large radiation errors. In this case, temperature differences up to 3.4 &amp;#176;C were observed compared to Kestrels that were shaded. The effect of a higher air temperature on the PET calculation is, however, surprisingly small. A sensitivity analysis showed that an increase of 3 &amp;#176;C in the air temperature results in a maximal PET reduction of 0.5 &amp;#176;C. We concluded that Kestrel sensors can very well be used for assessing differences between air temperatures and PET between two locations and assessing the thermal effects of urban designs, but care should be taken when air temperature measurements are carried out in the sun. We always recommend using the wind vanes to deviate from high radiant input orientations for the temperature sensor, and placing the stations next to each other at the beginning and at the end of the measurements to check whether the stations actually measure the same values. Any differences can be corrected afterwards.&lt;/p&gt;

Bio-meteorological assessment of outdoor micro-entrepreneurial informal communities in extreme heat- A case of two tropical Indian megacities

2020 ◽  
Author(s):  
Shreya Banerjee ◽  
Ariane Middel ◽  
Subrata Chattopadhyay
Keyword(s):  
Thermal Comfort ◽  
Health Risks ◽  
Thermal Sensation ◽  
Thermal Conditions ◽  
Thermal Exposure ◽  
Extreme Heat ◽  
Outdoor Thermal Comfort ◽  
Economic Activities ◽  
Informal Communities ◽  
The Impact

&lt;p&gt;Extreme heat and associated health risks are increasingly becoming threats to urban populations, especially in developing countries of the tropics. Although human thermal exposure in cities has been studied across the globe, biometeorological conditions in mixed-used spaces, informal economic activity settings, and informal settlements have received little attention. We present a comparative analysis of outdoor thermal comfort for informal micro-entrepreneurial communities in Kolkata and Mumbai. Both cities belong to the Aw K&amp;#246;ppen Climate Classification, which signifies tropical hot and dry or Savannah climate. Due to excessive humidity, uncomfortable thermal conditions persist year-round in both cities.&lt;/p&gt;&lt;p&gt;An extensive thermal comfort perception survey was conducted between November 2018 and August 2019 in three similar neighborhoods in each city with over 650 valid samples. The microentrepreneurial locations included two pottery markets (Kumbhadwada in Mumbai, &amp;#160;Kumartuli in Kolkata); two flower markets that are linear stretches of informal activity areas along very important transportation networks (Dadar in Mumbai, Mallickghat in Kolkata); a book selling and book binding market (Boipara in Kolkata); and an informal commercial area with apparel shops (Fashion Street in Mumbai).&lt;/p&gt;&lt;p&gt;Results show that outdoor thermal comfort varied by city, micro-enterprise, and season. Overall, Kolkata respondents reported warmer sensations compared to Mumbai respondents. During the winter, neutral Physiologically Equivalent Temperature (PET) was 27.50&lt;sup&gt;o&lt;/sup&gt;C in Kolkata and 23.75&lt;sup&gt;o&lt;/sup&gt;C in Mumbai. Annual neutral PET was 22.7&amp;#176;C and 26.5&amp;#176;C in Mallickghat and Boipara, respectively. Respondents in Boipara were more sensitive towards warmer sensation than in Mallickghat. Even during the winter, people reported warmer sensation votes. PET was a better predictor of the mean Thermal Sensation Vote (mTSV) compared to air temperature. In Mumbai, we report higher neutral PET for activities at the clothing market compared to other microentrepreneurial activities. Acclimatization significantly improved comfort in the summer, while evaporative cooling was beneficial in the winter. We further employed an ANCOVA to analyze the impact of various non-climatic variables on thermal comfort. Results reveal that behavioral and physiological attributes (presence in the location, expectation, beverage intake) impact the overall sensation in both cities. Availability of shading was a significant parameter in Kolkata, while shading had a negligible effect on outdoor thermal sensation in Mumbai neighborhoods.&lt;/p&gt;&lt;p&gt;This is the first study to assess outdoor thermal comfort conditions and perceptions of populations involved in various outdoor informal economic activities in India. Findings of this study help understand the heat health risks of informal communities and inform the design and revitalization of such spaces to improve thermal comfort.&lt;/p&gt;

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.

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