Introducing Urban Overheating—Progress on Mitigation Science and Engineering Applications

Zinzi, Michele; Santamouris, M.

doi:10.3390/cli7010015

Cited by 6 publications

(3 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To reduce urban heat island effects, advanced materials including reflective materials (Low-E and retro-reflective, thermochromic and fluorescent, photonic and plasmonic) and thermal storage materials (PCM coating), have been developed by the researchers which reduced building envelope surface temperature by up to 12% [35]. The use of reflective coating [36] and thermal storage materials [37] were shown to reduce the peak ambient temperature up to 1.5-2.0 °C and 8 °C, respectively. Moreover, introducing green infrastructures, such as green roofs and vertical vegetation on a city scale, may on average decrease the ambient temperature between 0.3-3 °C through transpiration cooling and maintain average leaf temperature at about 21 °C irrespective of weather conditions [38].…”

Section: Modifying Surrounding Micro-climatementioning

confidence: 99%

Building Adaptation to Extreme Heatwaves

Kumar

Alam

Sanjayan

2021

Springer Tracts in Civil Engineering

View full text Add to dashboard Cite

Climate change is aggravating the summer heatwaves, making them more severe, frequent and prolonged. During the heatwave period, buildings are overheated due to heat gain from surroundings which poses significant risks to the occupants. Therefore, adapting our buildings to extreme heatwaves is of paramount importance. This chapter aims to identify the factors contributing to overheating buildings and the associated mitigation measures. The identified overheating factors are low energy building design, lightweight construction materials, internal heat gain, occupant behaviour and urban heat island effect. The overheating mitigation measures are divided into four categories (1) Modification of local microclimate, (2) resistance to heat transfer from outdoor to indoor (3) Absorption of transferred heat through thermal mass, and (4) Release of trapped heat from indoor to outdoor. The effectiveness of each mitigation measure category depends on indoor and outdoor environmental conditions. Numerical analysis showed that the risk of experiencing heat stress during extreme heatwave decreases with increasing energy star rating of the houses in Melbourne, Australia. If the entire existing lower energy star rated houses can be upgraded to 5.4 star, the percentage of Melbourne population experiencing six severe heat stress hours will decrease from 50% to only 4% at 36 °C mean outdoor temperature. The heat-related mortality and morbidity also decreases with increasing house energy rating. Net-benefit analysis showed that upgrading the lower energy rated houses to 5.4 star is highly beneficial with net-benefit becoming positive within 2-5 years. Emerging technology like dynamic insulation material (DIM) which changes the resistance of the external walls and ceilings depending on the indoor and outdoor temperature can help to minimise overheating in a highly insualted and air-tight building. Numerical simulation showed that DIM reduces the indoor air temperature in bedroom and living room by up to 1.1 °C and 1.2 °C, respectively, in the case study building in Melbourne, Australia.

show abstract

Section: Modifying Surrounding Micro-climatementioning

confidence: 99%

Building Adaptation to Extreme Heatwaves

Kumar

Alam

Sanjayan

2021

Springer Tracts in Civil Engineering

View full text Add to dashboard Cite

show abstract

“…This is largely caused by the increased absorption of shortwave radiation and the excessive release of anthropogenic heat, as well as the decreased latent heat transfer [2]. This has serious implications for the economic costs and social well-being in cities, such as a doubling of the energy consumption to cool buildings, an increase in peak electricity demand, and a significant increase in heat-related mortality during summer periods [3][4][5]. It has long been known that urban heat islands (UHIs) occur in densely built-up areas and can be 5-6 • C warmer than the surrounding landscape [6].…”

Section: Introductionmentioning

confidence: 99%

Water-Stressed Plants Do Not Cool: Leaf Surface Temperature of Living Wall Plants under Drought Stress

et al. 2021

View full text Add to dashboard Cite

Urban green infrastructures offer thermal regulation to mitigate urban heat island effects. To gain a better understanding of the cooling ability of transpiring plants at the leaf level, we developed a method to measure the time series of thermal data with a miniaturized, uncalibrated thermal infrared camera. We examined the canopy temperature of four characteristic living wall plants (Heuchera x cultorum, Bergenia cordifolia, Geranium sanguineum, and Brunnera macrophylla) under increasing drought stress and compared them with a well-watered control group. The method proved suitable to evaluate differences in canopy temperature between the different treatments. Leaf temperatures of water-stressed plants were 6 to 8 °C higher than those well-watered, with differences among species. In order to cool through transpiration, vegetation in green infrastructures must be sufficiently supplied with water. Thermal cameras were found to be useful to monitor vertical greening because leaf surface temperature is closely related to drought stress. The usage of thermal cameras mounted on unmanned aerial vehicles could be a rapid and easy monitoring system to cover large façades.

show abstract

“…In the last decades, the field of urban climatology has been studying the role of urban form in urban climate phenomena, attempting to broaden the understanding of which spatial conditions exacerbate and reduce the risk of overheating (Zinzi & Santamouris, 2019). Two distinct morphological approaches can be recognised.…”

Section: Introductionmentioning

confidence: 99%

A Quantitative Morphological Method for Mapping Local Climate Types

Maiullari

Esch

Timmeren

2021

View full text Add to dashboard Cite

Morphological characteristics of cities significantly influence urban heat island intensities and thermal responses to heat waves. Form attributes such as density, compactness, and vegetation cover are commonly used to analyse the impact of urban morphology on overheating processes. However, the use of abstract large-scale classifications hinders a full understanding of the thermal trade-off between single buildings and their immediate surrounding microclimate. Without analytical tools able to capture the complexity of cities with a high resolution, the microspatial dimension of urban climate phenomena cannot be properly addressed. Therefore, this study develops a new method for numerical identification of types, based on geometrical characteristics of buildings and climate-related form attributes of their surroundings in a 25m and 50m radius. The method, applied to the city of Rotterdam, combines quantitative descriptors of urban form, mapping GIS procedures, and clustering techniques. The resulting typo-morphological classification is assessed by modelling temperature, wind, and humidity during a hot summer period, in ENVI-met. Significant correlations are found between the morphotypes’ characteristics and local climate phenomena, highlighting the differences in performative potential between the classified urban patterns. The study suggests that the method can be used to provide insight into the systemic relations between buildings, their context, and the risk of overheating in different urban settings. Finally, the study highlights the relevance of advanced mapping and modelling tools to inform spatial planning and mitigation strategies to reduce the risk of urban overheating.

show abstract

Introducing Urban Overheating—Progress on Mitigation Science and Engineering Applications

Abstract: Buildings and construction is the most important economic sector in the world after agriculture [...]

Cited by 6 publications

References 31 publications

Building Adaptation to Extreme Heatwaves

Building Adaptation to Extreme Heatwaves

Water-Stressed Plants Do Not Cool: Leaf Surface Temperature of Living Wall Plants under Drought Stress

A Quantitative Morphological Method for Mapping Local Climate Types

Contact Info

Product

Resources

About