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.

Human thermal comfort in Local climate zones of Berlin

2020 ◽  
Author(s):  
Ines Langer ◽  
Alexander Pasternack ◽  
Uwe Ulbrich
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Urban Areas ◽  
Heat Island ◽  
Climate Zones ◽  
Local Climate ◽  
Human Thermal Comfort ◽  
Local Climate Zones ◽  
Urban Heat ◽  
The City

<p>Urban areas show higher nocturnal temperature comparing to rural areas, which is denoted by urban heat island. This effect can intensify the impact of global warming in urban areas especially during heat waves, that leads to higher energy demand for cooling the building and higher thermal stress for residents.  </p><p>The aim of this study is to identify the Urban Heat Island (UHI) effect during the heat spell 2018 and 2019 in order to calculated human thermal comfort for Berlin. Berlin, the capital city of Germany covers an area of 892km<sup>2</sup> and its population is growing, therefore more residential areas will be planned in future through higher building. The methodology of this research is to divide Berlin into Local Climate Zones (LCZ's) regarding the concept of Stewart & Oke (2012). Then to evaluate the accuracy of this concept using 30 microclimate stations. Estimating the magnitude of urban heat island and its seasonal changes in combination with human thermal perception in different LCZ during summer time is another objective of this research. </p><p>Ten LCZ's for Berlin were selected, as class 1 (compact high rise), class 3 (compact low rise), class 7 (lightweight low-rise), class C (bush, scrub), class E (bare rock or paved) and class F (bare soil or sand) don't exist in Berlin. Class A (dense trees) is with a fraction of 18.6% in a good agreement with the percentage of dense trees reported from the city administration of Berlin (18.4%), class G (water) has a coverage of 5.1% through our classification instead of 6.7% reported by the city administration. In summary, the LCZ 1-10 cover 59.3% (more than half) of the city area.</p><p>Regarding temperature measurements, which represent a hot summer day with calm wind and clear sky the difference of Local Climate Zones will be calculated and the temperature variability in every LCZ's regarding sky view factor values show the hot spot of the city.</p><p>The vulnerability of LCZ's to heat stress will be ranked and discussed regarding ventilation and other factors.</p><p> </p><p>Literature</p><p>Matzarakis, A. Mayer, H., Iziomon, M. (1999) Applications of a universal thermal index: Physiological equivalent temperature: Intern. J. of Biomet 43 (2), 76-84.</p><p>Stewart, I.D., Oke, T.R. (2012) Local climate zones for urban temperature studies. Bull. Amer. Meteor. Soc. 93 1879-1900. DOI: 10.1175/BAMS-D-11-00019.1.</p><p> </p>

Urban Design Guidelines to Mitigate Urban Heat Island (UHI) Effects In Hot-Dry Cities

2015 ◽  
Vol 74 (4) ◽  
Author(s):  
Shima Taslim ◽  
Danial Monsefi Parapari ◽  
Arezou Shafaghat
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Urban Design ◽  
Urban Areas ◽  
Design Guidelines ◽  
Heat Island ◽  
Negative Effects ◽  
The Past ◽  
Urban Heat ◽  
Increasing Temperature

Global warming and undeniable climatic change in the world have led to decreasing thermal comfort for humans. Urban heat island (UHI) is the most documented phenomenon which has led to the increasing temperature in urban areas. It has received much focus in the past few decades to evaluate the main effective criteria of UHI. Street heat has negative effects on human health and will only worsen in future; these negative effects would double in hot and dry urban area. This paper investigates the effects of UHI in these cities and illustrates the important factors which make them extremely hot. The outcome of this study can be used to determine the key guidelines for urban designers, urban planners, architects and landscape designers to recline the UHI impressions in urban areas and make more thermal comfort for Burgher.

scholarly journals Cooling Strategies for Thermal Comfort in Cities: A Review of Key Methods in Landscape Design

2021 ◽  
Author(s):  
Mo Zou ◽  
Heng Zhang
Keyword(s):  
Urban Planning ◽  
Thermal Comfort ◽  
Urban Heat Island ◽  
Landscape Design ◽  
Urban Morphology ◽  
Outdoor Thermal Comfort ◽  
Theoretical Research ◽  
Heat Island ◽  
Design Elements ◽  
Urban Heat

Abstract Under the climate change scenario, the negative impacts of urban heat island (UHI) will exacerbate due to unsustainable urban planning and human activities. Thermal comfort has close relationships with UHI in urban areas. This paper is based on the studies of urban heat island, thermal comfort, microclimate and urban planning in cities in the recent decade, combined with cross-analysis research method. The key topics include vegetation and water conditions, the albedo of materials, urban morphology and more. By the comparative case studies in landscape projects, the results further reveal that the density of tree canopies, the natural structure and density of ground cover, the form of water features, the colour and texture of materials, and the scale of shading structures have different cooling effect and performance in outdoor thermal comfort improvement with specific features in the landscape design. It is also found that there are some external conditions that can influence design determinations in real practices. The purpose of this study is to provide theoretical research methods and evaluation of thermal comfort landscape design elements, and to provide guidance for future sustainable city research and landscape design.

scholarly journals Green Envelop Impact on Reducing Air Temperature and Enhancing Outdoor Thermal Comfort in Arid Climates

2019 ◽  
Vol 5 (5) ◽  
pp. 1124-1135 ◽  
Author(s):  
Sherine Wahba ◽  
Basil Kamil ◽  
Khaled Nassar ◽  
Ahmed Abdelsalam
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Electricity Consumption ◽  
Green Roofs ◽  
Mean Value ◽  
Outdoor Thermal Comfort ◽  
Heat Island ◽  
Consumption Rates ◽  
Urban Heat

Today Urban Cities faces energy and environmental challenges due to increased population, higher urbanization. The building sector has a big responsibility as it acquires high consumption rates in global energy and environmental scenarios. It is thought that the built environment in Egypt is responsible for 26% of the total overall national energy consumption, 62% of the total electricity consumption and around 70% of resultant CO2 emissions. The increased use of electrical appliances causes Urban Heat Island effect (UHI), which affect major urban centres. Adding green elements to any urban area is proved to be an effective strategy with numerous benefits to enhance the city's ecosystem, also mitigate the urban heat island measures. In this research Green roofs/walls can regulate outdoor air temperature by 10°C and improve outdoor thermal comfort by 2 Predicted Mean Value (PMV) values. The modelling of green strategy models can take into consideration design developments in areas with hot and dry climatic zones. The properties of green walls can directly affect the results of thermal comfort as leafs absorbs, reflects and transmits solar radiation, and increases the evapotranspiration.

scholarly journals Nature-Based Solutions: Thermal Comfort Improvement and Psychological Wellbeing, a Case Study in Genoa, Italy

2021 ◽  
Vol 13 (21) ◽  
pp. 11638
Author(s):  
Francesca Mosca ◽  
Giulia Maria Dotti Sani ◽  
Andrea Giachetta ◽  
Katia Perini
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Natural Environment ◽  
Urban Areas ◽  
Well Being ◽  
Heat Island ◽  
Convenience Sample ◽  
Critical Issues ◽  
Urban Heat ◽  
Set Up

The urban heat island (UHI) effect is among the most critical issues caused by human activities and high building density. UHI has severe impacts on the urban and natural environment as well as on human health and wellbeing. The research presented here aims at evaluating the effects of nature-based solutions (NBS) in improving the livability of a district in the city of Genoa, which is heavily cemented and a major example of the heat island phenomenon. This study focuses on the microclimatic benefits of urban heat island mitigation as well as on psychological and perceptual aspects. A preliminary analysis of the district through CFD simulations using Envi-met software allowed for selection of the most suitable areas for a system of punctual interventions in urban regeneration using nature-based solutions. For each area identified, we simulated the effects of different design scenarios on microclimate mitigation and thermal comfort improvement. In addition, to evaluate the perceptual benefits of the most well-performing design scenarios, we set up a web-based survey that was administered to a convenience sample of Genoa residents. In terms of aesthetic satisfaction and perception of improved conditions of physical and psychological well-being, the preferred design outcomes were those which emphasized a freer and more natural environment. This study shows that nature-based solutions can improve the overall conditions of dense urban areas; microclimate performance and psychological effects should be both considered in the design process in order to improve the wellbeing of urban citizens.

scholarly journals Evaluation of Biomimicry-based Strategies to Improve Exterior Environmental parameters: A numerical Study at Urban Scale in a tropical Climate

2021 ◽  
Vol 312 ◽  
pp. 02009
Author(s):  
Kevin Araque ◽  
Paola Palacios ◽  
Dafni Mora ◽  
Miguel Chen Austin
Keyword(s):  
Urban Areas ◽  
Design Methodology ◽  
Numerical Study ◽  
Environmental Parameters ◽  
Tropical Climate ◽  
Base Case ◽  
Heat Island ◽  
Urban Heat ◽  
Pet Index

Due to population growth, cities have expanded their urban areas, causing increased temperatures and vegetative scarcity. Therefore, studies have been carried out on the urban heat island phenomenon, its effect on people’s thermal stress, and how to mitigate this problem. This research aims to evaluate the application of biomimetic strategies for improving exterior environmental conditions on an urban scale under a tropical climate through dynamic simulation. The case study takes place in the Casco Antiguo of Panama. Here, two cases were evaluated (base case and proposed case). The proposed case consists of strategies obtained from the application of the biomimetic design methodology. The ENVI-met software was used to evaluate both cases, where the external environmental parameters are compared between both cases for the critical months (March and October) at 15:00. Results showed that the air temperature reached an average reduction for March of 1.9 °C and 2 °C for October, the Tmr had an increase up to 0.6 °C in March and the PET index decreased 1.7 °C in March and in October 2 °C. Although significant changes were obtained, high levels of discomfort persist due to the narrowness and proximity of the buildings in this urban settlement.

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