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

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.

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

Biomimetics ◽

10.3390/biomimetics6030048 ◽

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.

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Human thermal comfort in Local climate zones of Berlin

10.5194/egusphere-egu2020-7741 ◽

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

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.&#160;&#160;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 892km2 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.&#160;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.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.The vulnerability of LCZ's to heat stress will be ranked and discussed regarding ventilation and other factors.&#160;LiteratureMatzarakis, A. Mayer, H., Iziomon, M. (1999) Applications of a universal thermal index: Physiological equivalent temperature: Intern. J. of Biomet 43 (2), 76-84.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.&#160;

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Urban Heat Island Mitigation Strategies: Experimental and Numerical Analysis of a University Campus in Rome (Italy)

Sustainability ◽

10.3390/su12197971 ◽

2020 ◽

Vol 12 (19) ◽

pp. 7971 ◽

Cited By ~ 1

Author(s):

Gabriele Battista ◽

Luca Evangelisti ◽

Claudia Guattari ◽

Emanuele De Lieto Vollaro ◽

Roberto De Lieto Vollaro ◽

...

Keyword(s):

Urban Heat Island ◽

Urban Areas ◽

High Performance ◽

Energy Performance ◽

Climatic Conditions ◽

Mitigation Strategies ◽

Heat Island ◽

Negative Effects ◽

Local Overheating ◽

Urban Heat

The urban heat island (UHI) phenomenon is strictly related to climate changes and urban development. During summer, in urban areas, the lack of green zones and water sources causes local overheating, with discomfort and negative effects on buildings’ energy performance. Starting from this, an experimental and numerical investigating of the climatic conditions in a university area in Rome was achieved, also assessing the occurrence of the UHI phenomenon. The analyzed area was recently renewed, with solutions in contrast to each other: on one side, an old building was re-designed aiming at high performance; on the other hand, the neighboring areas were also refurbished leading to large paved surfaces, characterized by high temperatures during summer. A calibrated numerical model was generated through ENVI-met software and eight different scenarios were compared, to mitigate the overheating of this area and to analyze the influences of the proposed solutions in terms of air temperature reduction. The analysis of this case study provides information on potential mitigation solutions in the urban environment, showing that goals and priorities in the design phase should concern not only buildings but also external areas, also considering university areas.

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

Sustainability ◽

10.3390/su132111638 ◽

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.

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Microclimate Design Review (Study Case: TOD Area at Gedebage, Bandung)

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.103.63 ◽

2020 ◽

Vol 103 ◽

pp. 63-69

Author(s):

Marisa Sugangga ◽

Woerjantari Kartidjo ◽

Tubagus Muhammad Aziz Soelaiman

Keyword(s):

Thermal Comfort ◽

Urban Heat Island ◽

Urban Design ◽

Central City ◽

Heat Island ◽

Design Review ◽

Urban Heat ◽

The Impact ◽

Terminal Area

Design review is a stage that undertaken to improve the quality of a design in buildings, cities and landscapes. The design review stage can be used to minimize the impact that will occur. Inappropriate design in the planning of the central city of Bandung in Gedebage could have caused the phenomenon of Urban Heat Island (UHI) in the region. The occurrence of this phenomenon can cause the lack of thermal comfort in the area. The potential of Urban Heat Island (UHI) in the planned area can be detected early by conducting design review towards RTBL document of Gedebage Technopolis, Bandung. This study aims to assess the 2014 RTBL of Gedebage with simulation using the ENVI-Met 4.3.1 tool. Design review was carried out with a climate sensitive urban design (CSUD) approach so that the design of The Integrated Terminal area of Gedebage Technopolis can have thermal comfort accords with standard. In this study, it was found that the design of The Integrated Terminal area of Gedebage Technopolis includes in the comfortable category and it has an average Predict Mean Vote (PMV) value of 1.6 for 24 hours. In addition to evaluate the design, it was found that by adding the principle of climate sensitive urban design, a design can be improved and improved its quality of the microclimate. The initial recommendation that given is reducing building height, increasing open space, and replacing material in the pedestrian area.

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