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1 – 10 of 444The purpose of this study is to determine the effect of ventilation openings and fire intensity on heat transfer and fluid flow within the microclimate between 3D human body and…
Abstract
Purpose
The purpose of this study is to determine the effect of ventilation openings and fire intensity on heat transfer and fluid flow within the microclimate between 3D human body and clothing.
Design/methodology/approach
On account of interaction effects of fire and ventilation openings on heat transfer process, a 3D transient computational fluid dynamics model considering the real shape of human body and clothing was developed. The model was validated by comparing heat flux history and distribution with experimental results. Heat transfer modes and fluid flow were investigated under three levels of fire intensity for the microclimate with ventilation openings and closures.
Findings
Temperature distribution on skin surface with open microclimate was heavily depended on the heat transfer through ventilation openings. Higher temperature for the clothing with confined microclimate was affected by the position and direction of flames injection. The presence of openings contributed to the greater velocity at forearms, shanks and around neck, which enhanced the convective heat transfer within microclimate. Thermal radiation was the dominant heat transfer mode within the microclimate for garment with closures. On the contrary, convective heat transfer within microclimate for clothing with openings cannot be neglected.
Practical implications
The findings provided fundamental supports for the ease and pattern design of the improved thermal protective systems, so as to realize the optimal thermal insulation of the microclimate on the garment level in the future.
Originality/value
The outcomes broaden the insights of results obtained from the mesoscale models. Different high skin temperature distribution and heat transfer modes caused by thermal environment and clothing structure provide basis for advanced thermal protective clothing design.
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L. Kleerekoper, A.A.J.F. van den Dobbelsteen, G.J. Hordijk, M.J. van Dorst and C.L. Martin
Due to the predicted global temperature rise and local expansion and densification of cities, Urban Heat Islands (UHI) are likely to increase in the Netherlands. As spatial…
Abstract
Purpose
Due to the predicted global temperature rise and local expansion and densification of cities, Urban Heat Islands (UHI) are likely to increase in the Netherlands. As spatial characteristics of a city influence its climate, urban design could be deployed to mitigate the combined effects of climate change and UHIs. Although cities are already experiencing problems during warm-weather periods, no clear spatial means or strategies are available for urban designers to alleviate heat stress. The paper aims to discuss these issues.
Design/methodology/approach
There is a lack of knowledge on cooling effects that can be achieved through urban design in Dutch neighbourhoods. In this paper, the cooling effects of various design measures are compared on the level of urban blocks and neighbourhoods, with a focus on a 1960s neighbourhood in Amsterdam-West. The cooling effects are simulated by means of the microclimate model ENVI-met, here the effects on air temperature and physiological equivalent temperature will be evaluated.
Findings
The use of green, and a higher roof albedo in particular, seem to perform well as cooling measures. Combinations of cooling measures do not necessarily result in better performance and might even counteract other cooling effects. However, combinations of measures that lead to an increase in the environmental temperature show the largest heating.
Research limitations/implications
Effects of green roofs and facades are beyond the scope of this study, though future suggestions for this research will be included.
Originality/value
The results add to the body of knowledge in the area of climate design enabling policy makers and designers to estimate the effect of simulated measures in comparable neighbourhoods and thus improve thermal comfort in outdoor spaces.
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Emmanuel Otchere-Darko, Laura Atuah, Richard Opoku and Christian Koranteng
Green roofs are strategies for the ecological intensification of cities and a measure of meeting some of the sustainable development goals (SDGs). They have widely been adopted as…
Abstract
Purpose
Green roofs are strategies for the ecological intensification of cities and a measure of meeting some of the sustainable development goals (SDGs). They have widely been adopted as an adaptation strategy against an urban heat island (UHI). However, they are conventionally soil-based making it difficult and expensive to adopt as a strategy for greening existing buildings (GEB). This paper, therefore, develops a novel green roof system using climbers for thermal-radiative performance. The paper explores the vitality of climbing species as a nature-based strategy for GEB, and for the ecological improvement of the predominantly used cool roofs in sub-Saharan Africa (SSA).
Design/methodology/approach
Simulation for the same building Kejetia Central Market (KCM) Redevelopment; the existing aluminium roof (AL), soil-based extensive green roof (GR1) and the proposed green roof using climbing plants (GR2) were performed using ENVI-met. The AL and GR1 were developed as reference models to evaluate and compare thermal-radiative performance of the conceptual model (GR2). The long wave radiation emission (Qlw), mean radiant temperature (MRT) and outdoor air temperature (Ta) of all three roofing systems were simulated under clear sky conditions to assess the performance and plant vitality considering water access, leaf temperature (Tf) and latent heat flux (LE0) of GR1 and GR2.
Findings
There was no short wave radiation (Qsw) absorption at the GR2 substrate since the climbers have no underlying soil mass, recording daily mean average Qlw emission of 435.17 Wm−2. The soil of GR1, however, absorbed Qsw of 390.11 Wm−2 and a Qlw emission of 16.20 wm−2 higher than the GR2. The AL recorded the lowest Qlw value of 75.43 Wm−2. Also, the stomatal resistance (rs) was higher in GR1 while GR2 recorded a higher average mean transpiration flux of 0.03 g/sm3. This indicates a higher chance of survival of the climbers. The Ta of GR2 recording 0.45°C lower than the GR1 could be a good UHI adaptation strategy.
Research limitations/implications
No previous research on climbers for green roof systems was found for comparison, so the KCM project provided a unique confluence of dynamic events including the opportunity for block-scale impact assessment of the proposed GEB strategy. Notwithstanding, the single case study allowed a focussed exploration of the novel theory of redefining green roof systems with climbers. Moreover, the simulation was computationally expensive, and engaging multiple case studies were found to be overly exhaustive to arrive at the same meaningful conclusion. As a novelty, therefore, this research provides an alternative theory to the soil-based green roof phenomenon.
Practical implications
The thermal-radiative performance of green roofs could be improved with the use of climbers. The reduction of the intensity of UHI would lead to improved thermal comfort and building energy savings. Also, very little dependence on the volume of soil would require little structural load consideration thereby leading not only to cheaper green roof construction but their higher demand, adoption and implementation in SSA and other low-income economies of the global south.
Social implications
The reduction of the consumption of topsoil and water for irrigation could avoid the negative environmental impacts of land degradation and pollution which have a deleterious impact on human health. This fulfils SDG 12 which seeks to ensure responsible consumption of products. This requires the need to advance the research for improvement and training of local built environment practitioners with new skills for installation to ensure social inclusiveness in the combat against the intractable forces of negative climate impacts.
Originality/value
Climbers are mostly known for green walls, but their innovative use for green roof systems has not been attempted and adopted; it could present a cost-effective strategy for the GEB. The proposed green roof system with climbers apart from becoming a successful strategy for UHI adaptation was also able to record an estimated 568% savings on topsoil consumption with an impact on the reduction of pollution from excavation. The research provides an initial insight into design options, potentials and limitations on the use of climbers for green roofs to guide future research and experimental verification.
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Ga Yoon Choi, Hwan Sung Kim, Hyungkyoo Kim and Jae Seung Lee
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…
Abstract
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.
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Saghar Hashemi, Amirhosein Ghaffarianhoseini, Ali Ghaffarianhoseini, Nicola Naismith and Elmira Jamei
Given the distinct and unique climates in these countries, research conducted in other parts of the world may not be directly applicable. Therefore, it is crucial to conduct…
Abstract
Purpose
Given the distinct and unique climates in these countries, research conducted in other parts of the world may not be directly applicable. Therefore, it is crucial to conduct research tailored to the specific climatic conditions of Australia and New Zealand to ensure accuracy and relevance.
Design/methodology/approach
Given population growth, urban expansions and predicted climate change, researchers should provide a deeper understanding of microclimatic conditions and outdoor thermal comfort in Australia and New Zealand. The study’s objectives can be classified into three categories: (1) to analyze previous research works on urban microclimate and outdoor thermal comfort in Australia and New Zealand; (2) to highlight the gaps in urban microclimate studies and (3) to provide a summary of recommendations for the neglected but critical aspects of urban microclimate.
Findings
The findings of this study indicate that, despite the various climate challenges in these countries, there has been limited investigation. According to the selected papers, Melbourne has the highest number of microclimatic studies among various cities. It is a significant area for past researchers to examine people’s thermal perceptions in residential areas during the summer through field measurements and surveys. An obvious gap in previous research is investigating the impacts of various urban contexts on microclimatic conditions through software simulations over the course of a year and considering the predicted future climate changes in these countries.
Originality/value
This paper aims to review existing studies in these countries, provide a foundation for future research, identify research gaps and highlight areas requiring further investigation.
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Jennifer Adams and Emily Hannum
Physical victimization at school is little studied in impoverished developing country contexts. Moreover, the role of school and classroom contexts as risk factors remains poorly…
Abstract
Physical victimization at school is little studied in impoverished developing country contexts. Moreover, the role of school and classroom contexts as risk factors remains poorly understood.
The aim of the study is to investigate the prevalence of physical victimization in rural Chinese middle schools as well as the individual, teacher/classroom, and school-level risk factors associated with experiencing physical victimization.
We use two waves of longitudinal, representative survey data to perform a multilevel logistic regression analysis (MLRA) of physical victimization among middle school students from 100 villages in one of China’s poorest provinces. We focus on a subset of questionnaire items that were gathered from students when the sampled children were 13–16 years old. We also utilize student data from the first wave of the survey to control for prior internalizing problems and academic achievement. Finally, we link matched data collected from principal and teacher questionnaires to examine the risk factors for physical victimization associated with students’ microclimates and the wider school environment.
A substantial proportion of middle school students (40%) reported having been beaten by classmates. Elevated risk was found among males; students with prior poor performance in language; students with past internalizing problems; students of female teachers and teachers evaluated as low performing; students in disruptive classrooms; and students in classrooms undergoing mandated reforms.
These findings suggest that efforts to reduce school violence should not only focus on the deficits of individual students, but rather should target practices to alter the within school risk factors associated with microclimates.
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Pengpeng Cheng and Daoling Chen
The purpose of this paper is to analyze the influence of underwear on the microenvironment of human clothing.
Abstract
Purpose
The purpose of this paper is to analyze the influence of underwear on the microenvironment of human clothing.
Design/methodology/approach
Based on the basic laws of energy and mass conservation, the paper combined the theory of heat and mass transfer to establish the simulation of the influence of underwear on human thermal reaction in microclimate and prediction model of human thermal reaction law.
Findings
The impact on the microenvironment affected by tighter underwear is less than the effect of loose underwear and computational flow dynamics (CFD) can accurately predict the thermal reaction parameters’ values of the human body.
Originality/value
It can be effectively used for the prediction of heat exchange between human body and environment in high-temperature environment and human thermophysiological parameters, and overcomes the individual differences of human experiments and the danger and repeatability of high-temperature environmental experiments.
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Andrea Ciaramella, Valentina Puglisi and Tommaso Truppi
The article aims to describe the approach adopted within the framework of a multi-destination development project, the goal of which is to promote innovative technologies and…
Abstract
Purpose
The article aims to describe the approach adopted within the framework of a multi-destination development project, the goal of which is to promote innovative technologies and methods to evaluate the environmental quality of an urban district under construction.
Design/methodology/approach
The approach lies in the integration of methodologies usually applied on an urban scale (microclimate well-being and air quality, study of air quality), and/or to the individual building (acoustic comfort evaluation), never before adopted for assessment of plots or districts, especially in the dynamic evaluation of the variables identified, all objectively measurable. This method of analysis has been tested on an area of about 255,000 m2, located in the former historic district of the Fiera di Milano, where a series of typical urban functions (residential, commercial and trade) are inserted within a large public park.
Findings
The success of the work is represented by indicators (air quality, acoustic performance and microclimate) that relate to the finished district and that can be compared with average values in the same city. The system may constitute a protocol capable of bringing benefits to local authorities.
Research limitations/implications
The limit is the need of data that support the dynamic simulation (external factors as vehicular traffic, general neighbourhood activity, pollutant emissions) corresponding to the different seasons. These data are not always available by the municipalities.
Practical implications
This type of assessment could be requested of developers/builders for complex projects, resulting in changes to the initial plan if the assessment identifies critical issues related to the design choices (orientation of buildings, quality and presence of green areas, traffic emissions inside the urban district, etc.), with the ultimate goal of creating neighbourhoods with better environmental conditions.
Originality/value
The research produces solutions addressed to the Italian situation, but it identifies systems and methods used in other countries.
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Floriberta Binarti, Pranowo Pranowo, Chandra Aditya and Andreas Matzarakis
This study aims to compare the local climate characteristics of Angkor Wat, Borobudur and Prambanan parks and determine effective strategies for mitigating thermal conditions that…
Abstract
Purpose
This study aims to compare the local climate characteristics of Angkor Wat, Borobudur and Prambanan parks and determine effective strategies for mitigating thermal conditions that could suit Borobudur and Angkor Wat.
Design/methodology/approach
The study employed local climate zone (LCZ) indicators and ten-year historical climate data to identify similarities and differences in local climate characteristics. Satellite imagery processing was used to create maps of LCZ indicators. Meanwhile, microclimate models were used to analyze sky view factors and wind permeability.
Findings
The study found that the three tropical large-scale archaeological parks have low albedo, a medium vegetation index and high impervious surface index. However, various morphological characteristics, aerodynamic properties and differences in temple stone area and altitude enlarge the air temperature range.
Practical implications
Based on the similarities and differences in local climate, the study formulated mitigation strategies to preserve the sustainability of ancient temples and reduce visitors' heat stress.
Originality/value
The local climate characterization of tropical archaeological parks adds to the number of LCZs. Knowledge of the local climate characteristics of tropical archaeological parks can be the basis for improving thermal conditions.
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Funda Baş Bütüner, Aysem Berrin Cakmakli, Ahmet Can Karakadilar and Esra Deniz
This article explores the impacts of the changing land-use on urban heat island (UHI) in an urban transformation zone in Ankara (Türkiye). Identifying a characteristic rural…
Abstract
Purpose
This article explores the impacts of the changing land-use on urban heat island (UHI) in an urban transformation zone in Ankara (Türkiye). Identifying a characteristic rural landscape until the 1950s, the study area experienced a drastic land-use change by razing the fertile landscape of the city and replacing it with a sealed surface. Development of the squatter houses after the 1960s and, subsequently, the implementation of a new housing morphology have introduced new sceneries, scales and surface conditions that make the study area a noteworthy case to analyze.
Design/methodology/approach
Regarding the drastic spatio-temporal change of the study area, this research assesses the impacts of the changing land-use on UHI based on three periods. Using 1957, 1991 and 2021 aerial imaginaries and maps, it analyzes the temperature alteration caused by the changing land-use. To do so, different surface types, green patterns and built-up areas have been modeled using Ankara climatic data and transferred to ENVI-Met to calculate the Universal Thermal Climate Index (UTCI) values.
Findings
The calculation has been developed over a transect covering an area of 40 m × 170 m, which includes diversity in terms of architecture, landscape and open space elements. To encourage future design strategies, the research findings deliberate into three extents that discuss the lacking climate knowledge in the ongoing urban transformation projects: impervious surface ratio and regional albedo variation, changing aspect ratio and temperature variation at the pedestrian level.
Originality/value
Urban transformation projects, being countrywide operations in Türkiye, need to cover climate-informed design strategies. Herein, the article underlines the critical position of design decisions in forming a climate-informed urban environment. Dwelling on a typical model of housing transformation in Türkiye, the research could trigger climate-informed urban development strategies in the country.
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