RP2005: Urban Micro Climates

RP2005: Conference Paper: Thermal resilience and urban green infrastructures in public space: three case studies in Adelaide, South Australia

Australia has had seven extreme heatwaves since the beginning of the 20 th century. During heatwaves, public spaces in cities are frequently warmer than is confortable for humans. The regional warming projection of 2-5°C in Australia (by 2070) will be added to an existing 4-8°C extra heat in higher urban densities. This extra urban heat is because of urban structures, land cover, lifestyle and lack of landscape. Under question is how and to what extent contemporary public spaces can become more resilient to emerging higher temperatures in cities while maintaining their usability. In this paper, we define thermal resilience in public space as the ability of the space to support its normal activities in higher temperatures.

We also report on the correlations between activity patterns, thermal conditions and urban greenery in Hajek Plaza, Rundle Mall and Hindmarsh Square in Adelaide, South Australia. Case studies were monitored from February 2013 to April 2014 when experiencing temperatures between 20°C and 42°C. Results indicate that both necessary and optional activities are highly sensitive to heat stress in public space and both start to decline after the Apparent Temperature (APT) reaches the threshold of 28-32°C. Activities in public spaces with more urban greenery show more resilience to excess heat, while shadowless and hard-landscaped public spaces lose their embodied activities in lower APTs. As such, urban greenery can facilitate more diverse and extended activities in public space especially in higher temperatures. Thus, an increase in the tree canopy and softer landscapes are suggested to achieve higher thermal resilience in public space.

Read the full paper here: https://bit.ly/33da1iK%20

RP2005: Journal Article: Policy recommendations to increase urban heat stress resilience

As the frequency and intensity of heatwaves are growing, strategies to improve our resilience are becoming more vital. Policies to increase heat stress resilience are mostly isolated across different disciplines and government departments. A holistic approach would be necessary that mitigates the numerous negative impacts of heatwaves on public health, urban infrastructure and services through adaptation to heatwaves in the realm of public health, building and construction industry, and urban planning and infrastructure.

This paper reviews the research on heat stress adaptation measures, before presenting recommendations for a range of integrated policy measures to increase the heat stress resilience of urban populations in Australian cities. The recommended policy measures include information dissemination, incentives and disincentives, promotion, demonstration and regulations. The paper concludes by identifying directions for further research and reinforcing the multiple benefits that can result from the implementation of heat stress resilience policies and strategies.

Read the full article here: https://doi.org/10.1016/j.uclim.2018.05.001

SP2005: Journal Article: The effect of building facades on outdoor microclimate – dependence model development using terrestrial thermography and multivariate analysis

This paper describes ground-based thermal infrared (TIR) data collection and the development of a multivariate regression model to predict brightness surface temperature from thermal images. The statistical model estimates surface temperature regressed against thermal image red, green and blue (RGB) values with high predictive strength (R2 = 0.992) for later multi-image stitching and facet-scale spatio-temporal analyses within a Geographical Information Systems (GIS) environment.

Read the full article here: https://doi.org/10.1016/j.proeng.2017.04.295 

RP2005: Journal Article: Heat stress-resistant building design in the Australian context

In Australia, heatwaves are the deadliest natural hazard and a major driver of peak electricity demand. The disproportionately high peak demand increases electricity prices, causes occasional blackouts and exacerbates energy poverty, all of which limit one’s ability to use air conditioning. Meanwhile, increased energy efficiency of dwellings may decrease their heat stress resistance. This paper challenges whether the current Australian Nationwide Energy Rating Scheme encourages heat stress resistance.

Cooling consumption, peak cooling demand and the risk of indoor overheating were assessed for a typical single-storey home in Adelaide and Sydney. Design options between 6 and 8 stars, plus two traditional, energy-inefficient homes were simulated with the AccuRate energy simulation program.

This paper demonstrates that the NatHERS does not directly encourage heat stress resistance in new homes and can even deliver buildings with worse heat resistance and increased reliance on air conditioning than traditional, energy-inefficient buildings. This overreliance on air conditioning can present a public health hazard, consequently, the integration of heat stress resistance in the Nationwide House Energy Rating Scheme is recommended.

Recommendations for the analysis and assessment of heat stress resistance are provided.

Read the full article here: https://doi.org/10.1016/j.enbuild.2017.10.025

RP2005: Journal Article: Spatial and activity preferences during heat stress conditions in Adelaide

Outdoor thermal discomfort pushes citizens into air-conditioned buildings and causes increased demand for water and electricity in the majority of Australian urban heat islands. Citizens’ spatial and activity preferences during heat stress conditions are under investigation in this paper. Citizens’ outdoor activity choices in different thermal environments were surveyed in Adelaide from September 2013 to April 2014. The post-activity questionnaire survey of outdoor activities in Adelaide indicates that necessary, optional and social activities decreased during outdoor heat stress more than any other thermal conditions.

Outdoor activities were chosen the most in neutral and warm thermal environments. Outdoor activity choices were affected significantly by the urban microclimate parameter of solar radiation. Tree canopy, shading (from buildings or temporary elements) and water features were the most attractive public space features for outdoor participants during heat stress conditions in Adelaide. Meanwhile, essential shopping and dining facilities and social events affect citizens’ outdoor activity choices during heat stress conditions. Thus, increased green infrastructures and supportive land uses are a prerequisite of urban transformation towards high-performance built environment in the context of climate change.

Read the full article HERE

RP2005: Journal Article: Patterns of urban heat island effect in Adelaide: a mobile traverse experiment

Urban structure, hard surfaces and shortage of vegetation cause an artificial temperature increase in cities, known as the urban heat island effect. This paper determines the daily patterns of urban heat in Adelaide, Australia. The near-surface temperature profile of Adelaide was mapped in 60 journeys alongside a straight cross route connecting Adelaide Hills to the West Beach between 26 July and 15 August 2013.

Results indicate that the most intense urban-rural temperature differences occurred during midnight in Adelaide. However, the afternoon urban heat had more temperature variation in the urban area. In the late afternoon, the near-surface urban heat fluctuates by 2°C within three kilometres and by 1.2°C in just one kilometer. Afternoon heat stress can vary based on space configurations and urban surface covers. Afternoon heat stress causes the highest heat load on urban dwellers. A better understanding of daily urban heat variations in cities assists urban policy making and public life management in the context of climate change.

Read the full article here: doi: https://doi.org/10.5539/mas.v11n4p80

RP2005: Journal Article: Comparative analysis of surface urban heat island effect in central Sydney

The Urban Heat Island (UHI) effect can result in higher urban densities being significantly hotter (frequently more than 4 °C, even up to 10 °C) compared to their peri-urban surroundings. Such artificial heat stress increases the health risk of spending time outdoors and boosts the need for energy consumption, particularly for cooling during summer. Urban structure, land cover and metabolism are underlined as key contributors in city scale. Under question is which urban configurations can make urban precincts and their microclimates more resilient to the surface layer Urban Heat Island (sUHI) effect?

The City of Sydney is increasingly experiencing the UHI effect due to its numerous urban development projects and changes in climate. In the Sydney context, this ongoing research aims to explore the most heat resilient urban features at precinct scale. It covers five high density precincts in central Sydney and is based on a nocturnal remote-sensing thermal image of central Sydney taken on 6 February 2009. Comparing the surface temperature of streetscapes and buildings’ rooftops (dominant urban horizontal surfaces), indicates that open public spaces and particularly streetscapes are the most sensitive urban elements to the sUHI effect. The correlations between street network intensity, open public space plot ratio, urban greenery plot ratio and sUHI effect is being analysed in Sydney’s high density precincts. Results indicate that higher open space plot ratio and street network intensity correlate significantly to higher sUHI effect at precinct scale. However, higher urban greenery plot ratio can effectively mitigate the sUHI effect in high density precincts.

Read the full article here: Doi: 10.5539/jsd.v7n3p23

RP2005: Journal Article: Correlation analysis of surface temperature of rooftops and streetscapes and urban heat island effect: case study of central Sydney

Cities are frequently experiencing artificial heat stress, known as the Urban Heat Island (UHI) effect. The UHI effect is commonly present in cities due to increased urbanization, where anthropogenic heat and human modifications have altered the characteristics of surfaces and atmosphere. Urban structure, land cover and metabolism are underlined as UHI key contributors and can result in higher urban densities being up to 10°C hotter compared to their peri-urban surroundings. The UHI effect increases the health-risk of spending time outdoors and boosts the need for energy consumption, particularly for air-conditioning during summer. Under investigation is what urban features are more resilient to the surface layer Urban Heat Island (sUHI) effect in precinct scale.

In the context of Sydney, this ongoing research aims to explore the most heat resilient urban features at precinct scale. This UHI investigation covers five high-density precincts in central Sydney and is based on a nocturnal remote-sensing thermal image of central Sydney taken on 6 February 2009. Comparing the surface temperature of streetscapes and buildings’ rooftops (dominant urban horizontal surfaces), indicates that open spaces and particularly streetscapes are the most sensitive urban elements to the sUHI effect. The correlations between street network intensity, open space ratio, urban greenery ratio and the sUHI effect is being analysed in Sydney’s high-density precincts. Results indicate that higher open space ratio and street network intensity correlate significantly to higher sUHI effect at precinct scale. Meanwhile, 10% increase in the urban greenery can effectively decrease the precinct temperature by 0.6°C.

Read the full article here: https://apo.org.au/node/243686

RP2005: Conference paper: Socio-environmental impacts of heat stress in public spaces of Australian cities: spatial heat resilience and its application in low carbon cities

This PhD research - presented at State of Australian Cities 2015 (Gold Coast) - investigates the social impacts of heat stress in Australian cities.

Socio-environmental impacts of heat stress in public spaces of Australian cities: spatial heat resilience and its application in

RP2005: Book Chapter: Green space policies in the transition to the ecocity: governance, multifunctionality and narrative

Urban green space provides multiple benefits to city dwellers—both human and non-human. These ‘nature-based solutions’ include mitigating urban heat and stormwater runoff, providing biodiversity habitat and contributing to human health and wellbeing, and social and cultural processes, which are key elements in creating ecological cities. In the transition to eco-cities, public policies for urban green space provision can make substantial contributions. However, in the transition from existing mono-functional, mechanistic policy approaches, there are challenges in creating a vision for urban green space that navigates beyond the splintered narratives of single-function priorities.

This chapter investigates how urban green space policies in Melbourne, Australia address these challenges, and the roles that communication, engagement and narrative play.

Request the chapter HERE.

RP2005: Conference Paper: Cooling cities with green space: a policy analysis framework

The urban heat island effect, in which cities are hotter than surrounding rural areas, will be exacerbated by climate change impacts for many Australian cities. Heatwaves already kill more people than other natural disasters, and have significant impacts on productivity and liveability.

Vegetation is one of the most effective mitigation options for the urban heat island effect. However, in many Australian cities, green space is under increasing pressure from urban densification and sprawl. To date, green space planning has a relatively weak role in urban planning, and the links between urban planning and provision of urban green space, and its broader urban liveability contributions, are largely missing.

This paper provides an overview of the urban heat island effect, and urban greenery's role in its mitigation. Following this, it presents an analysis framework to assess the effectiveness of Australian policies in retaining and maximising urban greenery.

The framework utilises research on sustainability transitions to structure the criteria for analysing policies. The framework focuses on policy processes and content to assess policy effectiveness and to define policy 'success'.

The authors propose that a key component of policy effectiveness is gaining cross-organisational 'ownership' and agency for policy implementation from across multiple departments within the policy's jurisdiction. Reflecting urban greenery's multi-functionality, they propose that policy success is associated with it being integrated and embedded across departments within an organisation (for example transport, recreation, open space, strategic planning, assets management, etc.); and when a range of urban greenery's multiple contributions are actively and intentionally utilised.

Read the paper HERE.

RP2005: Conference Paper: Green roofs in Australia: review of thermal performance and associated policy development

In Australia, there is an increasing interest in using extensive green roofs to make buildings more sustainable and provide a number of social, ecological, aesthetic and thermal benefits to cities. The potential of green roofs to reduce building energy consumption has been extensively studied overseas in a variety of different climates. However, in Australia the green roof industry is relatively new. There is still very little information on the thermal properties of Australian green roofs and their performance. Further, as a relatively new industry, there is a general lack of specific policies and initiatives to promote green roofs.

In this paper, we briefly review the research investigating green roof thermal performance in various climates and analyse policies and actions that have been implemented internationally to foster green roofs with an emphasis on their thermal performance.

The results showed that most policies were focused on ecological benefits, such as stormwater runoff reduction, rather than thermal benefits. Many green roof policies had difficulty interpreting the thermal performance of green roofs, because of the dynamic nature of green roof R-values. In this study, the effectiveness of overseas green roof policy is discussed and recommendations how they could be adapted for Australian cities are provided. Keywords: Green roofs; thermal performance; building; policy.

Green roofs in Australia: review of thermal performance and associated policy development (348630 PDF)

RP2005: Conference Paper: Limits of thermal adaptation in cities: a case study of Darling Harbour, Sydney

Climate change projections indicate a likely 3.8°C increase in the average temperature in Australia by 2090. During summer, outdoor heat-stress causes significant thermal discomfort, altering outdoor living preferences.This paper aims to explore the neutral and critical thresholds for outdoor thermal adaptation.

The paper reports on outdoor activity change during different outdoor microclimates in Darling harbour, Sydney. Results indicate that outdoor participants adjust their insulation and activity rate by an outdoor neutral thermal threshold of 28-30°C. For the thermal environments hotter than this neutral threshold, the pattern of adaptation shifts towards modification and dismissal of optional, social and ultimately necessary activities. Such thermal adaptation continues to occur by an outdoor critical thermal threshold of 28-48°C. After the critical thermal threshold, outdoor activity prevention becomes the major thermal adaptation strategy. Therefore, to support usability of public spaces during summer heat-stress conditions, public spaces are required to provide thermal environments closer to neutral and no hotter than critical thermal thresholds.

Read the paper HERE.

RP2005: Conference Paper: Outdoor activity and spatial choices of citizens during heat stress conditions: a case study of Adelaide, South Australia

During summer heatwaves, public spaces are frequently warmer than human thermal comfort preferences in a majority of Australian Cities. Citizens’ preferences of public space elements and supportive features during heat-stress conditions are under particular focus in this paper.

Outdoor activity choices in different thermal environments were surveyed in Adelaide from September 2013 to April 2014. This post-activity survey indicates that necessary, optional and social activities decreased during outdoor heat-stress more than any other thermal conditions.

Outdoor activities were chosen the most in neutral and warm thermal environments. Outdoor activity choices were affected significantly by the magnitude of solar radiation. Tree canopy, shading (from buildings or temporary elements) and water features were the most attractive public space features for outdoor participants during heat-stress conditions in Adelaide. Meanwhile, essential shopping and dining facilities and social events affect citizens’ outdoor activity choices during heat-stress conditions. Thus, increased green infrastructures and supportive land uses are a prerequisite of urban transformation for climate change adaptation.

Read the paper HERE.

RP2005: Conference Paper: Transforming cities towards an ecological worldview: applying sustainability transition theories and resilience thinking to urban planning

Cities are complex and dynamic social-ecological systems; both human and ecological systems are in mutual interaction. As a social-ecological system, a city's form and structure can change over time. The transcendence and durability of cities is in fact due to their continuous change. Major transformations are often viewed as technological or socio-technological transitions, such as how transport, communication, and housing are fulfilled, and include changes to user practices, regulations, networks, infrastructure, and symbolic meaning. Theories of sustainability transitions investigate the processes by which innovations in socio-technical systems, arising in niches, displace existing dominant or mainstream technologies.

Research to date has focused on applying the theories to sustainability transitions in energy systems, water systems, and zero emission housing. These systems all fit easily within a 'socio-technical' conceptual framework. How can theories of sustainability transitions apply to innovations in social-ecological systems?

The purpose of this paper is to propose viewing transitions and transformations through the perspective of an ecological worldview. An ecological worldview sees humans as active participants in the co-creation of the living systems we inhabit, and understands that living systems are characterized by change, and therefore by uncertainty and unpredictability. A resilience thinking epistemology, one that is marked by complex relationships, along with transitions and transformations, is used to guide the research. Here, resilience thinking helps us to understand that the world is not mechanical and reasonably predictable, helping us to further grasp the concept of an ecological worldview.

This paper develops a new framework for analysing the transition process of policy innovations that links sustainability transitions and an ecological worldview. This framework is applied to San Francisco, Oakland, and Vancouver using live/work policies to explore new ways of theorizing innovations in complex and dynamic social-ecological systems.

Read the paper

RP2005 Conference Paper: Overheating risk in the Australian Nationwide House Energy Rating Scheme : A case study of Adelaide

Hatvani-Kovacs, G., Belusko, M., Pockett, J., Boland, J., 2016. Overheating risk in the Australian Nationwide House Energy Rating Scheme : A case study of Adelaide, in: Zuo, J., Daniel, L., Soebarto, V. (Eds.), 50th International Conference of the Architectural Science Association, Adelaide, 7-9 December 2016. The Architectural Science Association and The University of Adelaide, Adelaide, South Australia, pp. 437–446.

Heatwaves are Australia’s most deadly natural hazard and the principle driver of peak electricity demand in South Australia. The disproportionately high peak demand increases electricity prices, causes occasional blackouts and exacerbates energy poverty, all of which limit the use of air-conditioning. Meanwhile, the desire for more energy efficient homes may decrease their heat stress resistance. This paper challenges whether the current Australian Nationwide Energy Rating Scheme encourages heat stress resistance.

Cooling consumption, peak demand and the risk of indoor overheating were assessed for a typical single-storey home in Adelaide. Design scenarios between 6 and 8 stars, plus two additional, traditional building structures were simulated with the AccuRate building thermal simulation program. A new overheating analysis is proposed based on the combination of the Excess Heat Factor and the Adaptive Comfort Model.
Although the uninsulated, double brick scenario required significantly more heating, that configuration also outperformed many scenarios with higher star ratings during summer. A higher star rating did not necessarily coincide with a decrease in cooling consumption, demand and overheating. Consequently, the integration of heat stress resistance in the Nationwide Energy Rating Scheme would be advantageous to avoid building new homes with potentially lower coping capacity and increased dependence on air-conditioning.

Hatvani-Kovacs, G., Belusko, M., Pockett, J., Boland, J., 2016. Overheating risk in the Australian Nationwide House Energy (389446 PDF)

RP2005 Conference Paper: Assessment of heatwave impacts

Hatvani-Kovacs, G., Belusko, M., Pockett, J., Boland, J., 2016. Assessment of heatwave impacts. Procedia Engineering 4th Int. Conf. Countermeasures to Urban Heat Island, 30-31 May 1 June 2016, Natl. Univ. Singapore 169, 316–323

The frequency and intensity of urban heatwaves (UHWs) have been growing worldwide due to climate change and the exacerbating effects of urban heat islands (UHIEs). UHWs have many negative impacts, including excess negative health outcomes (e.g. morbidity), energy (consumption and peak demand) and water consumption. Most studies have evaluated these impacts separately even though there is an interplay between them. The study assessed the daily excess morbidity, energy demand and consumption, and water supply in the Adelaide metropolitan region during heatwaves, between January 2008 and March 2014. The assessment quantifies the thresholds and the increase in each impact relative to temperature increase. The demonstrated negative impacts on public health, and energy and water resources, potentially exacerbated by UHIEs, justify the importance of interdisciplinary research and integrated policy changes on the mitigation of and adaptation to heatwaves.

Read the article HERE.

RP2005 Journal Article: Heat stress risk and resilience in the urban environment.

Hatvani-Kovacs, G., Belusko, M., Skinner, N., Pockett, J. & Boland, J., (2016). Heat stress risk and resilience in the urban environment. Sustainable Cities and Society, 26, p.278–288.

Abstract

Heatwaves have been subject to significant attention in Australia and globally due to their negative impacts on the ecosystem, infrastructure, human health and social life. Measures to increase resilience to heatwaves, however, are mostly isolated in different disciplines. This paper proposes a framework integrating urban and infrastructure planning, building design, public health and social research to comprehensively assess heat stress resilience. The proposed framework can assist decision makers in the evaluation of different policy changes addressing heat stress resilience and contribute to more comprehensive and effective heatwave management. An online survey was undertaken with a representative sample (N = 393) from Adelaide, South Australia, to explore heat stress resistance of the built environment, adaptation and heat-related, self-reported health problems. The study established the magnitudes of the secondary negative impacts of heatwaves on public health and daily routines. The findings identify a low level of resistance to heat stress by the built environment. It was concluded that community education along with focused building and planning regulations has the potential to significantly increase heat stress resilience.

Read the article

RP2005 Journal Article: Drivers and barriers to heat stress resilience

Hatvani-Kovacs, G., Belusko, M., Skinner, N., Pockett, J. & Boland, J., (2016). Drivers and barriers to heat stress resilience. Science of The Total Environment, 571,p.603–614.

Abstract Heatwaves are the most dangerous natural hazard to health in Australia. The frequency and intensity of heatwaves will increase due to climate change and urban heat island effects in cities, aggravating the negative impacts of heatwaves. Two approaches exist to develop population heat stress resilience.

Firstly, the most vulnerable social groups can be identified and public health services can prepare for the increased morbidity. Secondly, the population level of adaptation and the heat stress resistance of the built environment can be increased. The evaluation of these measures and their efficiencies has been fragmented across research disciplines.

This study explored the relationships between the elements of heat stress resilience and their potential demographic and housing drivers and barriers. The responses of a representative online survey (N = 393) about heat stress resilience at home and work from Adelaide, South Australia were analysed. The empirical findings demonstrate that heat stress resistant buildings increased adaptation capacity and decreased the number of health problems. Air-conditioning increased dependence upon it, limited passive adaptation and only people living in homes with whole-house air-conditioning had less health problems during heatwaves.

Tenants and respondents with pre-existing health conditions were the most vulnerable, particularly as those with health conditions were not aware of their vulnerability. The introduction of an Energy Performance Certificate is proposed and discussed as an effective incentive to increase the heat stress resistance of and the general knowledge about the built environment.

Read the article HERE.

RP2005: Journal Article: Resilience to heat in public space: a case study of Adelaide, South Australia

Sharifi, E., Sivam, A., & Boland, J. (2016). Resilience to heat in public space: a case study of Adelaide, South Australia. Journal of Environmental Planning and Management, 1-22. doi: 10.1080/09640568.2015.1091294 (still online due to published in hard-copy in mid 2016).

During summer heatwaves, heat load exacerbates in urban heat islands (especially in hot climates) and threatens public life in cities. This paper examines the links between urban microclimates, outdoor thermal discomfort and public life through an exploratory case study. Heat resilience is highlighted as the ability of the space to support its normal activities when experiencing out-of-comfort temperatures. It also reports on the correlations between heat sensitive outdoor activities and urban greenery in three disparate case studies in Adelaide. Results indicate that necessary and optional activities start to decline after the apparent temperature reaches the threshold of 28 °C–32 °C, while activities in public spaces with more urban greenery show higher resilience to heat stress. Research findings propose heat resilience as a quality indicator in public space and support the application of urban greenery to make urban settings more resilient to heat stress.

Access the article

RP2005: Journal Article: Can the Excess Heat Factor Indicate Heatwave-Related Morbidity? A Case Study in Adelaide, South Australia

Hatvani-Kovacs, G., Belusko, M., Pockett, J., Boland, J., 2015. Can the excess heat factor indicate heatwave-related morbidity? A case study in Adelaide, South Australia. EcoHealth. doi:0.1007/s10393-015-1085-5

Although heatwave-related excess mortality and morbidity have been widely studied, results are not comparable spatially and often longitudinally because of different heatwave definitions applied. The excess heat factor (EHF) quantifies heatwave intensity relative to the local climate, enabling cross-regional comparisons. Previous studies have shown a strong relationship between EHFs and daily mortality during severe heatwaves. An extensive study about the relationship between EHFs and daily morbidity compared to the currently applied heatwave thresholds in Adelaide has not yet been undertaken. This paper analyzes the association of EHFs with daily morbidity between 2008 and 2014 in the Adelaide metropolitan region, South Australia, and probes three different approaches to calculate the EHF. The EHF is found to differentiate days with heatwave-related excess morbidity significantly better than other widely used weather parameters, resulting in fewer days per year with heatwave alerts than using previously proposed methods. The volume of excess morbidity can be predicted by the EHF more reliably with a model proposed for the SA Ambulance Service to support their heatwave preparation plan.

Access the article

RP2005: Conference Paper: Drivers and barriers to heatwave-resilient building retrofitting in the Australian context

2-4 December 2015, Melbourne; Conference paper presented at 49th International Conference of the Architectural Science Association. Hatvani-Kovacs, G., Belusko, M., Pockett, J., & Boland, J. (2015). Drivers and barriers to heatwave-resilient building retrofitting in the Australian context.

Heatwaves have a mounted interest in the last decade due to their negative impacts on infrastructure, the ecosystem and public health. Population exposure to heat stress is substantially influenced by the resilience of the built environment as people spend the majority of their time indoors. Retrofitting the existing building stock could profoundly improve heatwave resilience, however, the current knowledge of the population’s heatwave-resilient retrofitting willingness is limited. An online survey about population perception of, adaptation to and retrofitting against heatwaves was conducted with a representative sample from the Adelaide metropolitan region in March 2015. The survey results about the retrofitting relevant questions presented in this paper suggest that the perceived financial limitations and missing tenant/landlord incentives represent the key barriers to domestic retrofitting. Beyond air-conditioning, the improvement of shadings was the most prevalent retrofitting measure. The number of known and applied retrofitting measures, nevertheless, were limited. Solutions, such as taking advantage of increased garden vegetation or changing the roof colour were underrepresented. Special attention should be paid to older population since they are not only more vulnerable to heatwaves but also less willing to retrofit their homes.

Access the conference paper online.

Conference Paper: Drivers and barriers to heatwave-resilient building retrofitting in the Australian context (443386 PDF)

RP2005: Journal Article: Retrofitting Precincts for Heatwave Resilience: Challenges and Barriers in Australian Context

2015 Gertrud Hatvani-Kovacs and John Boland. 'Retrofitting Precincts for Heatwave Resilience: Challenges and Barriers in Australian Context' in Challenges , 6 (1), 3-25; doi:10.3390/challe6010003

As the frequency and intensity of heatwaves are growing in Australia, strategies to combat heat are becoming more vital. Cities are exposed to urban heat islands (UHIs) due to excess urbanisation. In this study, a definition of urban heatwave (UHW) is conceptualised to investigate the combined impacts of heatwaves and UHIs. To quantify the negative impacts of UHW, indicators—such as excess morbidity, electricity and water consumption—are considered. The intensity of UHWs is calculated using the unit of excess heat factor (EHF), developed by the Australian Bureau of Meteorology. EHF enables the comparability of UHWs in different geographical locations. Using the indicators and the intensity of UHWs, a calculation method to quantify heatwave resilience at a precincts scale is proposed. The study summarises the assumed influential factors of precinct heatwave resilience based on the existing literature and propose a “cool retrofitting toolkit” (CRT). CRT creates the framework to assess the adaptation to and mitigation of UHWs available to retrofit existing precincts, and to evaluate potential retrofitting strategies in terms of energy and carbon efficiency, financial affordability and perceived acceptability by population. This study illuminates the importance of climate, function, built environment and population characteristics-conscious retrofitting.

View article

RP2005: Journal Article: A Subambient Open Roof Surface under the Mid-Summer Sun

2015 Angus R. Gentle andGeoff B. Smith. 'A Subambient Open Roof Surface under the Mid-Summer Sun' in Advanced Science.  Article first published online: 26 MAY 2015. DOI: 10.1002/advs.201500119. Online ISSN: 2198-3844

If a surface is under intense sunlight and open to warm air, cooling to below ambient has up to now been an elusive target. The technical goal is super-cool roofi ng with thermal performance well above that of existing cool roofs. Stringent spectral requirements at solar and infrared (IR) wavelengths are needed, leading to quite limited choices for suitable coating materials and layer structure. Metal alone, except silver, cannot provide the required level of solar reflectance of above 96% and the thermal emittance of common metals is far too low to cool. Placing silver under a glass or polymer material with very low solar absorptance may cool well as high emittance E r results. However, options such as PMMA and most glasses absorb too much solar radiation. Low iron glass and various polyesters including PET absorb very little solar energy if thin, but their IR spectral response is not ideal for this task. Cooling is enhanced if IR spectral response in the thermal emission band involves a mix of moderate refl ectance at those wavelengths where the atmosphere irradiates the earth under clear sky conditions and very high absorptance hence emission in the range from 7.9 μm < λ < 14 μm, called the “sky window,” which is largely free of incoming radiation as it views the cold of space. Super-cool surfaces require solar refl ectance and sky window absorptance to be close to 100%. The admix of IR reflectanceand absorptance in the down-welling atmospheric radiation band is less stringent but together with the sky window setting determines the value of overall thermal emittance E r which dictates the heat output rate at the roof temperature T r . This radiative rate is an important practical consideration. Its final choice depends on total rate of heat input including the contribution of absorbed down-welling atmospheric radiation. We concluded that the desired combination of solar and IR criteria could be met using two or more specially chosen polyesters on a silver layer. At the set thickness, their IR absorptance had to be very strong in slightly different sections of the sky window with moderate transmittance at incoming wavelengths. A suitable surface was produced and set up outdoors. It remained subambient throughout a hot summer day including under the peak intense solar intensity of 1060 W m −2 , with ambient at 27 ÅãC, and high IR intensity from the atmosphere of 400 W m −2 .

View article

RP2005: Journal Article: Local measures to mitigate the urban heat island effect in hot and humid climate: comparative case study of Sana’a, Bushehr and Dubai Marina

2014 Sharifi, E. and Lehmann, S.: ‘Local measures to mitigate the urban heat island effect in hot and humid climate: comparative case study of Sana’a, Bushehr and Dubai Marina’, in International Journal of Development and Sustainability, Vol. 3, No. 1 (2014), Japan, ISSN2168-8662 (published Feb 2014), pp. 38-54

Abstract

Cities experience the effect of extra heat compared to their rural surroundings. This phenomenon is known as the Urban Heat Island (UHI) effect. Urban geometry, land cover, landscape and metabolism have been cited as the main contributors to the UHI effect. This paper compares the UHI mitigation strategies of the contemporary development of Dubai Marina (United Arab Emirates) with historical cities of Sana’a (Yemen) and Bushehr (Iran). Shadow patterns, wind flow, vegetation ratio, surface materials and energy consumption are being investigated to measure their effectiveness on microclimate moderation in hot and humid climate. The study benefits from aerial imagery feature extraction, climate data and spatial measurements as primary sources. An analysis chart based on Strengths, Weaknesses, Opportunities and Threats (SWOT analysis) is being used to facilitate discussion about future development in Dubai Marina. Results indicate that increasing the use of permanent shadow, natural ventilation, permeable materials and vegetation can contribute to mitigate the UHI effect, while the use of surface water, car-oriented transport networks and free standing buildings can magnify the UHI effect in hot and humid climates. The outcome design guidelines can be used in cities in hot and humid climate, which intend to mitigate the UHI effect.

View article

RP2005 Report: Does the Australian Nationwide House Energy Rating Scheme ensure heat stress resistance?

Hatvani-Kovacs, G., Belusko M., Pockett, J., Boland J., 2016, Does the Australian Nationwide House Energy Rating Scheme ensure heat stress resistance? 20 pp.

The report was undertaken as part of a PhD research, funded by the CRC for Low Carbon Living Ltd. supported by the Cooperative Research Centres program, an Australian Government initiative and a research student scholarship granted from the Australian Building Codes Board. 

Access the full report

RP2005: Overview of Comparative study of major contributors to the Urban Heat Island effect in three Australian cities: Sydney, Melbourne and Adelaide

Overview of the $1.2 million research initiative to identify cost-effective strategies for mitigation of urban heat islands in Australian cities. ‘Urban Micro Climates: Comparative Study of Major Contributors to the Urban Heat Island (UHI) in three Australian cities (Sydney, Melbourne and Adelaide)’ is a three-based urban strategy for decision makers and policy formulation to reduce heat stress in three Australian cities.

This project will develop a cross-disciplinary, multi-scale understanding of Australian cities’ microclimates, by focusing on the UHI effect and the interplay between urban form, density, surfaces and ambient temperature. It will be undertaken collaboratively by researchers from three universities, the CRC-WSC, two city councils, government bodies and industry partners.

rp2005 urban micro climates booklet (8998277 PDF)

RP2005: Fact Sheet: Policy recommendations to increase urban heat stress resilience

A range of policy recommendations are presented here across the four disciplines of public health, building and construction industry, and urban planning and infrastructure - emerging from CRC for Low Carbon Living (CRCLCL) project research findings related to heat stress in urban Australia.

uhi policynote5 factsheetformat (1105408 PDF)

RP2005 FACTSHEET: Cooling cities with green space – policy success factors

As cities grapple with the impacts of heatwaves, exacerbated by the urban heat island effect and amplified by climate change, green spaces can cool urban areas and provide other functions and benefits to city dwellers’ health and wellbeing. Public policies play an important role in retaining and maximising urban green spaces.

uhi factsheet3 green space policy success policy position final (1236408 PDF)

RP2005 FACTSHEET: Staying safe during heatwaves - a South Australian example

An extreme heatwave is a period of successive days (three days in SA) when the temperature is considerably hotter than the concluding month and a 30-year average. Extreme heatwaves in Adelaide usually last up to three days. Following CRCLCL research, this factsheet provides tips on staying safe during excessive heat.

uhi factsheet4 stay safe in heatwaves final (917216 PDF)

RP2005 FACTSHEET: Mitigating urban heat with green spaces

As cities grapple with the impacts of heatwaves, exacerbated by the urban heat island effect and amplified by climate change impacts, green spaces can cool urban areas, as well as provide health and wellbeing benefits to city dwellers and habitat for biodiversity.

uhi factsheet1 heat mitigation final (1151936 PDF)