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It is generally accepted that building external wall design affects its ability to protect occupants from weather extremes, such as heatwaves. However, there is no established methodology to assess this ability in assisting building designers to identify the most resilient design. This study aims at developing an analytical tool to examine wall hea...
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The design of low energy buildings requires accurate thermal simulation software to assess the heating and cooling loads. Such designs should sustain thermal comfort for occupants and promote less energy usage over the life time of any building. One of the house energy rating used in Australia is AccuRate, star rating tool to assess and compare the...
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... In two Australian cities, Adeliade [202]and Melbourne [93,94,207], the influence of heatwaves on building energy consumption and thermal comfort was explored by comparing star-rated insulated buildings to existing non-insulated buildings. In Adelaide, a tool recommended by the Nationwide house energy rating scheme (NatHERS) was used to evaluate energy efficiency, that uses TMY data. ...
... The study's limitation was the approximation of heatwave identification. Another research conducted in Melbourne employed the numerical model to assess the thermal performance of eight different wall systems during heatwaves [207]. Similar to the prior study, an insulated wall system with higher thermal inertia was determined to be the most suitable alternative over an uninsulated wall system. ...
... Melbourne [207] during protracted periods of intense heat. ...
Most cities across the globe are affected by urban overheating (UO), which is one of the most well-documented local-scale climate change phenomena. Extreme heat events have become more intense and severe in the twenty-first century, posing a substantial hazard to human health. Over the years, significant variations in global weather patterns have also been documented. The UO alters the land-atmospheric interactions and affects the regional and global climatic conditions. The synergies between such local, regional, and global climate changes, which may adversely affect health, economy, energy, and environmental quality, have never been examined and are a major concern in the context of global warming and rapid urbanization. Further, the combined impact of such climatic changes on the built environment has never been investigated and is also a pressing issue in the context of overheating and GHG emissions. The dissertation’s primary goal is to examine the interactions between local-scale UO, regional-scale heatwaves, and large-scale synoptic climatology and to assess how these affect the built environment. The association between UO, heatwaves, and large-scale weather patterns was investigated using the surface energy budget and innovative techniques, including the gridded weather typing classification (GWTC). The newly developed urban building energy models (UBEMs) were employed to investigate the combined impact of such climatic changes on the built environment. There had been reports of positive synergy between UO and heatwaves when the magnitude of UO increased dramatically. The key synergistic interactions between UO and heatwaves were the advective heat flux and land-coast distance, where the lack of coastal winds penetration during heatwaves kept the inland regions warmer by altering the available energy. The tropical maritime Tasman airmass (coming from north of the Tasman sea) and temperate maritime weather patterns were primarily responsible for humid-warm (HW) and humid conditions in the region during heatwaves. In addition to these moist unstable conditions, a significant impact of tropical continental airmass, arising over central Australia, was also documented during heatwaves, another thermal regulator between inland and coastal zones. A drastic increase in urban cooling energy needs and serious overheating issues in the built environment was also concluded under the combined impact of such climate changes, which was associated with the same dualistic large-scale weather systems. This research is the first of its kind, identifying the impact of microscale and mesoscale climate on the built environment and presenting solutions to counteracting global climatic change. The guidelines provided in the dissertation will aid in designing thermally resilient and heat-responsive cities.
... Outdoor temperature and human activities determine indoor temperature [15,139]. In discussions on indoor temperature, thermal comfort is regarded as an important factor in protecting the residents of a building against extreme weather conditions, including heatwaves [140]. Thermal comfort inside buildings is considered neutral at a temperature of 26 • C, and overheating at 28 • C or above [141]. ...
With the global acceleration of urbanization, temperatures in cities are rising continuously with global climate change, creating an imminent risk of urban heat islands and urban heating. Although much research has attempted to analyze urban heating from various perspectives, a comprehensive approach to urban planning that addresses the problem is just beginning. This study suggests a conceptual framework for multidisciplinary understanding of urban heating by reviewing 147 selected articles from various fields, published between 2007 and 2021, that discuss urban heating mitigation. From these, we identified several outdoor and indoor temperature-reduction factors and proposed area-based, zoning-based, and point-based approaches to mitigate urban heating.
... 20 For the Hunter, brick veneer homes make up around 50% of all homes, 34 and these have more issues during heatwaves if they are old and poorly insulated. 35 Well-designed homes do not require much energy to remain comfortable in all weather, and have passivedesign features such as: ...
... Bushfire precautions at home 4,6,9,11,12,13,22,27,31,33,35 hazard reduction, 31 ceiling, 4,9,10,15,16,17,18,19,26,28,33 Central Coast,6,26,31,35 climate,4,5,6,7,12,17,19,24,27,31,32,33,34 11,12,15,16,18,19,20,21,23,24,27,28,29,34 Wollemi,6 Index continued ...
As the climate gets hotter, occupants of Australian homes will experience more discomfort and heat stress, more difficulty sleeping, more danger from bush-fires, and possibly more power outages in extreme weather conditions. This is because Australian homes perform poorly, and climate projections indicate there will be more extreme heatwaves.
Cooling your home aims to help residents, particularly those in NSW and the Hunter, to be safer and more comfortable at home in climate extremes, with practical advice on home retrofits, appliance choices and cost-effective strategies including:
• installing retrofits in critical areas such as gaps, ceilings and external shading
• simple behavioural adaptations to stay cool
• creating an efficient one-room Cool Retreat
• updating appliances and using them more strategically
• considering a heatwave emergency plan
• taking bush fire precautions at home
The rapidly growing urban population, along with the increasing urban energy needs and greenhouse gas (GHG) emissions, poses a serious threat to the global climate. Local, regional, and global climatic conditions synergistically interact and affect urban energy performance and thermal comfort. The combined impact of such local, regional and global climatic change on the buildings' thermal performance has never been studied. In the present study, the combined impact of urban overheating (UO) and heatwaves (HWs) on building thermal performance have been investigated by employing the urban building energy model (UBEM). Further, the sensitivity analyses were performed using various adaptive measures to evaluate the impact on cooling needs and indoor comfort. Under the synergistic impact of UO and HWs, the cooling penalties were recorded up to 650%, the increase in mean indoor temperature was up to 5.8°C, and the deterioration in passive survivability was registered up to 31%. Under the combined impact of various adaptive measures, the cooling savings were recorded up to 97%, the drop in mean indoor temperature was up to 2.34°C, and the improvement in passive survivability was up to 20% during HWs. The present study might assist in revising the building codes to counteract the global climatic change and improve building resilience during extreme heat conditions.
Global and local climate change increases the occurrence and the magnitude of extreme phenomena, as urban heat island and heat waves. These phenomena seriously affect the quality of life in several aspects: society, health, environment; they also heavily affect the building sector, increasing the energy use for cooling and deteriorating the indoor thermal environment. This paper utilizes data from a continuous urban microclimatic monitoring over three years to quantify the impact of heat waves on the thermal quality of two reference residential buildings in the city of Rome, Italy. The synergic effect of heat waves with the urban heat island is also analysed. The observation period includes summers of 2015, 2016 and 2017. The buildings’ response is analysed through numerical thermal analyses in transient regime, taking into account several variants: thermal insulation, mechanical cooling system and thermal free-floating conditions, with different night ventilation strategies. Results show that daily average temperature and urban heat island intensity increase by up to 4.3 °C and 1.5 °C respectively during the heat waves with respect to the rest of the summer. The building cooling energy use rises up 87% during heat wave periods, while average operative temperature in free-running buildings increments by up to 3.5 °C. Results also show the impressive combined impact of heat wave and heat island: triplication of cooling energy use in the worst case and increase of the average operative temperature above 5 °C.
Overheating in built environments during climate extreme heat events is a major concern to human health, particularly for people vulnerable to prolonged exposure to heat and humidity. However, currently available methods for assessing the risk of overheating lack robust procedures to evaluate the effects of overheating on the comfort and health of vulnerable occupants residing in the various different dwellings. This paper developed a general methodology to define and characterise overheating events and evaluate the risk to reduced comfort and undesirable health effects of building occupants exposed to extreme heat events. Criteria to declare overheating were developed based on heat-related health outcomes related to limits for body dehydration and core temperature of healthy average-age and older adults. The methodology was then applied to a case study of a residential building with typical local construction practice for cold climates and compared with existing methods for assessing risk from exposure to extreme heat events. The results showed that all the methods predicted that highly insulated and airtight buildings are more prone to overheating than older buildings that are less well insulated and airtight. However, only the proposed methodology described in this paper predicted that natural ventilation through opening windows significantly reduced the overheating risk to below the threshold value. Furthermore, multi criteria methods might be difficult to apply in practice in that it is not guaranteed to violate all the criteria to declare a building space is not overheated. The proposed methodology sets the groundwork for establishing a benchmark model from which different overheating metrics can be compared.
In light of the current EU guidelines in the energy field, improving building envelope performance cannot be
separated from the context of satisfying the environmental sustainability requirements, reducing the costs associated with the life cycle of the building as well as economic and financial feasibility. Therefore, identifying the “optimal” energy retrofit solutions requires the simultaneous assessment of several factors and thus becomes a problem of choice between several possible alternatives. To facilitate the work of the decision-makers, public or private, adequate decision support tools are of great importance. Starting from this need, a model based on the multi-criteria analysis “AHP” technique is proposed, along with the definition of three synthetic indices associated with the three requirements of “Energy Performance”, “Sustainability Performance” and “Cost”. From the weighted aggregation of the three indices, a global index of preference is obtained that allows to “quantify” the satisfaction level of the i-th alternative from the point of view of a particular group of decision-makers.
The model is then applied, by way of example, to the case-study of the energetic redevelopment of a former factory, assuming its functional conversion. Twenty possible alternative interventions on the opaque vertical closures, resulting from the combination of three thermal insulators families (synthetic, natural and mineral) with four energy retrofitting techniques are compared and the results obtained critically discussed by considering the point of view of the three different groups of decision-makers.
Occupant thermal comfort in lightweight buildings received increasing attention among architects and designers in applying modern methods of construction (MMC) today. These methods employ offsite, pre-fabrication strategies to reduce construction time. However, potential risk of overheating and deteriorated thermal comfort conditions in the lightweight constructions products are likely to be introduced, and potentially exacerbated at a warming climate. Phase change materials (PCMs) can be used as a heat sink to absorb heat from sun during the day, and reduce rapid room temperature rise due to added thermal stability from PCMs. To examine the effectiveness of a lightweight building using PCMs, a one dimensional numerical model was developed in this paper and solved by an enthalpy method with an explicit scheme. The performance of PCMs on cooling a lightweight building with brick veneer residential wall in hot summer of 2009 in Melbourne was predicted numerically. A comparison of the internal wall surface temperatures was made between a conventional lightweight wall and a PCM wall. It was observed that a reduction in wall surface temperature is possible when PCMs with a liquidus temperature of 26°C was integrated with west wall. The study reveals that application of PCMs into lightweight building could achieve better thermal comfort and energy savings in summer.
