Search results

This paper aims to study the use of cool roof technology to avoid unnecessary energy consumption in supermarkets. This will allow to reduce and even cancel the heat absorbed by the roofs, transferring it to the buildings and thus, creating more sustainable cities.

Thirteen real supermarkets with cool roofs were analysed in Australia, Canada, the USA and Spain. An analysis of so many supermarkets located in different parts of the world with different climatic zones has allowed an inductive analysis, obtaining real data of energy consumption associated with the air conditioning installations for a year with and without implementing the cool roof technology.

The paper provides insights on how the use of cool roof managed to reduce the need for energy for heating, ventilating and air conditioning by between 3.5 and 38%. Additionally, this technology reduces the annual generation of carbon dioxide (CO₂) emissions per square meter of supermarket up to 2.7 kgCO₂/m². It could be an economical technology to apply in new and old buildings with a period of average economic recovery of four years.

Because of the chosen research approach, the research results may be generalisable. Therefore, researchers are encouraged to test proposals in construction with other uses.

The paper includes economic and environmental implications for the development of cool roof technology and smooths the way for its implementation to increase energy efficiency in commercial buildings.

This paper is an innovative contribution to the application of cool roof technology as a source of energy savings in commercial construction through the analysis of supermarkets located in different countries with different climate zones. This will help other researchers to advance in this field and facilitate the implementation of the technology.

This paper aims to increase the resilience of building systems, especially roofs, in relation to climate changes. The focus is on Mediterranean cities, where, often, there is no regulation about these issues. Therefore, it is necessary to define resilience indicators through comparative studies of adaptive roof solutions to mitigate overheating in summer.

Through software simulations and data comparison, a specific methodological approach is used to analyze the resilience levels of different roof solutions (phase change materials, aerogel, green and cool roof), starting from energy efficiency as a prerequisite of resilience. Moreover, a case study of a historic existing building in a southern Italian town is examined.

The findings show the best strategies for building systems, especially for roofs, to decrease urban heat island effects according to the defined resilience indicators against overheating mitigation.

Other building systems, such as facades, also have to be investigated in relation to climate change mitigation.

The implementation of resilient solutions that can also affect neighborhood for urban heat island mitigation.

Because of resilience indicators definition, it is easier to introduce economic incentives according to reference thresholds and to increase community involvement.

The paper provides a new approach for the evaluation of technological solutions for a building from a resilience point of view, which has energy efficiency as pre-condition.

Green roofs are strategies for the ecological intensification of cities and a measure of meeting some of the sustainable development goals (SDGs). They have widely been adopted as an adaptation strategy against an urban heat island (UHI). However, they are conventionally soil-based making it difficult and expensive to adopt as a strategy for greening existing buildings (GEB). This paper, therefore, develops a novel green roof system using climbers for thermal-radiative performance. The paper explores the vitality of climbing species as a nature-based strategy for GEB, and for the ecological improvement of the predominantly used cool roofs in sub-Saharan Africa (SSA).

Simulation for the same building Kejetia Central Market (KCM) Redevelopment; the existing aluminium roof (AL), soil-based extensive green roof (GR1) and the proposed green roof using climbing plants (GR2) were performed using ENVI-met. The AL and GR1 were developed as reference models to evaluate and compare thermal-radiative performance of the conceptual model (GR2). The long wave radiation emission (Q_lw), mean radiant temperature (MRT) and outdoor air temperature (T_a) of all three roofing systems were simulated under clear sky conditions to assess the performance and plant vitality considering water access, leaf temperature (T_f) and latent heat flux (LE₀) of GR1 and GR2.

There was no short wave radiation (Q_sw) absorption at the GR2 substrate since the climbers have no underlying soil mass, recording daily mean average Q_lw emission of 435.17 Wm⁻². The soil of GR1, however, absorbed Q_sw of 390.11 Wm⁻² and a Q_lw emission of 16.20 wm⁻² higher than the GR2. The AL recorded the lowest Q_lw value of 75.43 Wm⁻². Also, the stomatal resistance (r_s) was higher in GR1 while GR2 recorded a higher average mean transpiration flux of 0.03 g/sm³. This indicates a higher chance of survival of the climbers. The T_a of GR2 recording 0.45°C lower than the GR1 could be a good UHI adaptation strategy.

No previous research on climbers for green roof systems was found for comparison, so the KCM project provided a unique confluence of dynamic events including the opportunity for block-scale impact assessment of the proposed GEB strategy. Notwithstanding, the single case study allowed a focussed exploration of the novel theory of redefining green roof systems with climbers. Moreover, the simulation was computationally expensive, and engaging multiple case studies were found to be overly exhaustive to arrive at the same meaningful conclusion. As a novelty, therefore, this research provides an alternative theory to the soil-based green roof phenomenon.

The thermal-radiative performance of green roofs could be improved with the use of climbers. The reduction of the intensity of UHI would lead to improved thermal comfort and building energy savings. Also, very little dependence on the volume of soil would require little structural load consideration thereby leading not only to cheaper green roof construction but their higher demand, adoption and implementation in SSA and other low-income economies of the global south.

The reduction of the consumption of topsoil and water for irrigation could avoid the negative environmental impacts of land degradation and pollution which have a deleterious impact on human health. This fulfils SDG 12 which seeks to ensure responsible consumption of products. This requires the need to advance the research for improvement and training of local built environment practitioners with new skills for installation to ensure social inclusiveness in the combat against the intractable forces of negative climate impacts.

Climbers are mostly known for green walls, but their innovative use for green roof systems has not been attempted and adopted; it could present a cost-effective strategy for the GEB. The proposed green roof system with climbers apart from becoming a successful strategy for UHI adaptation was also able to record an estimated 568% savings on topsoil consumption with an impact on the reduction of pollution from excavation. The research provides an initial insight into design options, potentials and limitations on the use of climbers for green roofs to guide future research and experimental verification.

As the global population keeps increasing with its associated urbanisation and climate change issues being experienced in various degrees worldwide, there is the need to find mitigating measures to improve thermal conditions within spaces. The study aimed to evaluate green roofs to determine whether they could provide thermal comfort within residential buildings.

Forty-two-year weather data were retrieved from the Kumasi weather station to establish the pattern of the climatic variables. Furthermore, an experiment was conducted by constructing test cells to determine the potential of vegetation/green roofs on temperature development within spaces. This approach led to a simulation-based exploration of the thermal performance of the test cells to probe variables that could lead to the reduction in temperature after the models in the software (design-builder) had been validated.

The results on the 42 years (1976–2018) weather data showed a significant (p = 0.05) mean temperature increment of 2.0 °C. The constructed test cell with Setcreasea purpurea (Purple Heart) vegetation showed an annual mean temperature reduction of 0.4 °C (p = 0.05). In addition, the exploration using the simulation application showed combinations of various soil depth (70–500 mm) and leaf area indices (leaf area index of 2–5) having a potential to lower indoor temperature by 1.5 °C and its associated reduction in energy use. The option of green roofs as a valuable alternative to conventional roofs, given their potential in mitigating climate change, must be encouraged. A survey of occupants in six selected neighbourhoods in Kumasi showed varying subjective perceptions of several green issues (24–98%) and increases in temperature values because of the loss of greenery in the city.

Empirical data that point to the significant reduction of indoor temperature values and a subsequent reduction in energy use have been unearthed. Therefore, built environment professionals together with city authorities could invest in these sustainable measures to help humanity.

The need to design buildings with due consideration for bioclimatic and passive design is central to promoting sustainability in the built environment from an energy perspective. Indeed, the energy and atmosphere considerations in building design, construction and operation have received the highest consideration in green building frameworks such as LEED and BREEAM to promote SDG 9: Industry, Innovation and Infrastructure and SDG 11: Sustainable Cities and Communities and contributing directly to support SDG 13: Climate Action. The research literature is rich of findings on the efficacy of passive measures in different climate contexts, but given that these measures are highly dependent on the prevailing weather conditions, which is constantly in evolution, disturbed by the climate change phenomenon, there is pressing need to be able to accurately predict such changes in the short (to the minute) and medium (to the hour and day) terms, where AI algorithms can be effectively applied. The dynamics of the weather patterns over seasons, but more crucially over a given season means that optimum response of building envelope elements, specifically through the passive elements, can be reaped if these passive measures can be adapted according to the ambient weather conditions. The use of representative mechatronics systems to intelligently control certain passive measures is presented, together with the potential use of artificial intelligence (AI) algorithms to capture the complex building physics involved to predict the expected effect of weather conditions on the indoor environmental conditions.

The environmental performance of several flat roof systems with different materials and insulation thicknesses is compared using life cycle assessment (LCA), with the aim to determine the roofing materials with the highest environmental performance. The paper aims to discuss these issues.

The calculations were carried out for an existing apartment block with a 300 m² flat roof. Five insulation materials with three different heat resistances each, five types of waterproof layers, three covering layers, and a green roof are assessed using LCA. Foreground data including maintenance are obtained from roofing companies, and background data are taken from Ecoinvent. ReCiPe is used as impact method. Energy losses through the roof are calculated using the energy software EPA-W.

Improving the insulation from 2.5 to 5 m²K/W leads to reductions of the damage scores from about 10 to 40 per cent. Polyisocyanurate and expanded polystyrene were found to have the lowest environmental damage, although the differences are small. Regarding the other layers, PVC mechanically fixed, ethylene propylene diene monomer (EPDM) mechanically fixed, EPDM glued and PVC with gravel ballast were found to have the lowest environmental damage of the materials assessed.

The outcomes of this study will aid building owners and construction and maintenance companies to choose renovation options for flat roofs with the lowest impact on the environment.

A smart choice of materials for a roofing system, with enough consideration of other aspects such as practical applicability, can thus significantly improve the environmental performance of the roof of a building.

The purpose of this paper is to prepare heat insulating exterior emulsion coating and to study its heat insulating property along with mechanical, chemical and weathering resistance properties with varying amount of hollow glass microspheres and cenospheres.

For heat insulating effect, various compositions were made by incorporating different proportions of hollow glass microspheres (HGM) and cenospheres (C). The mechanical, chemical, morphological and optical properties of the coating films were studied and compared.

Addition of hollow glass microspheres and cenospheres enhanced heat insulating property of the coating, hardness, tensile strength and wet scrub resistance. It was evaluated that optimum loading for both cenospheres and hollow glass microspheres was 10 wt.% and both the systems showed good mechanical, chemical resistance and weathering properties.

Addition of hollow glass microspheres and cenospheres to acrylic emulsion coating is a simple and inexpensive method.

The new heat insulating coatings with good thermal insulation properties and improved weather resistance were prepared. These coatings could find applications in demanding fields such as exterior wall coatings and roof coatings.

The adverse impacts of climate change coupled with rapid informal urbanization in the Southern African region are increasing the vulnerability of already sensitive population groups. Consequently, these urban regions are highly vulnerable to urban heat island effects and heatwaves due to exogenous and endogenous factors. While the dynamic interplay between the built environment, climate and response strategies is known, this paper highlights the lived experience of informal settlement residents. It presents work from a project undertaken in Melusi, an informal settlement in Tshwane, South Africa, as a multi-disciplinary project focusing on improving the local resilience to climate change associated heat stress.

Following a mixed method approach, a semi-structured observational analysis of the spatial layout and material articulation of selected dwellings along with the continuous monitoring and recording of their indoor environments were undertaken.

The paper presents the research results in terms of the dwelling characteristics, as spatial and material-use strategies and documented heat stress exposure in these structures. The findings highlight that informal dwellings perform poorly in all cases due to endogenous factors and that inhabitants experience extreme heat stress conditions for between 6 and 10 h daily during the peak summer period.

Currently, there are little empirical data on the heat stress residents living in informal settlements in Southern Africa are experiencing. This article provides insight into the indoor environments of informal dwellings and hopes to contribute future guidelines or heat health policies.

Due to the predicted global temperature rise and local expansion and densification of cities, Urban Heat Islands (UHI) are likely to increase in the Netherlands. As spatial characteristics of a city influence its climate, urban design could be deployed to mitigate the combined effects of climate change and UHIs. Although cities are already experiencing problems during warm-weather periods, no clear spatial means or strategies are available for urban designers to alleviate heat stress. The paper aims to discuss these issues.

There is a lack of knowledge on cooling effects that can be achieved through urban design in Dutch neighbourhoods. In this paper, the cooling effects of various design measures are compared on the level of urban blocks and neighbourhoods, with a focus on a 1960s neighbourhood in Amsterdam-West. The cooling effects are simulated by means of the microclimate model ENVI-met, here the effects on air temperature and physiological equivalent temperature will be evaluated.

The use of green, and a higher roof albedo in particular, seem to perform well as cooling measures. Combinations of cooling measures do not necessarily result in better performance and might even counteract other cooling effects. However, combinations of measures that lead to an increase in the environmental temperature show the largest heating.

Effects of green roofs and facades are beyond the scope of this study, though future suggestions for this research will be included.

The results add to the body of knowledge in the area of climate design enabling policy makers and designers to estimate the effect of simulated measures in comparable neighbourhoods and thus improve thermal comfort in outdoor spaces.