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Thermal performance of green roofs through field evaluation
Abstract
Green roofs have the potential to improve the thermal performance of a roofing system through shading, insulation, evapotranspiration and thermal mass, thus reducing a building's energy demand for space conditioning. To quantify the thermal performance and energy efficiency of green roofs in Canada, the National Research Council of Canada (NRC) has constructed an experimental facility, the Field Roof Facility (FRF), in its Ottawa campus. A median divider separates the roof of the FRF in two equal areas: a generic extensive green roof and a modified bituminous roof. Both roof sections are instrumented to allow direct comparison of the thermal performance the Green Roof and the Reference Roof. Observations from the FRF showed that a generic extensive green roof could reduce the temperature and the daily temperature fluctuation experienced by the roof membrane significantly in the warmer months (spring and summer). The Green Roof also significantly moderated the heat flow through the roofing system and reduced the average daily energy demand for space conditioning due to the heat flow through the roof in the summer by more than 75%. The Green Roof was more effective in reducing heat gain than heat loss. Les terrasses-jardins peuvent aider à améliorer la performance thermique d'une toiture, grâce à l'ombrage, l'isolation, l'évapotranspiration et la masse thermique qu'elles engendrent, réduisant ainsi la demande en énergie d'un immeuble pour le conditionnement de ses espaces. Pour quantifier la performance thermique et l'efficacité énergétique des terrasses-jardins au Canada, le Conseil national de recherches Canada (CNRC) a construit une installation expérimentale, le Field Roof Facility (FRF), sur son site d'Ottawa. Le toit du FRF a été séparé en deux zones égales par une cloison. D'un côté, une grande terrasse-jardin générique, de l'autre un toit en bitume modifié. Les deux zones sont équipées d'instruments de mesure pour permettre une comparaison directe de la performance thermique de la terrasse-jardin et du toit témoin. Les observations relevées sur le FRF indiquent qu'une terrasse-jardin réduit sensiblement la température et les fluctuations des températures quotidiennes subies par le revêtement d'étanchéité dans les mois chauds (printemps et été). La terrasse-jardin modère sensiblement le flux de chaleur dans le système de couverture et réduit la demande moyenne en énergie quotidienne pour le conditionnement des espaces par plus de 75%, grâce au flux de chaleur emmagasiné dans la couverture pendant l'été. La terrasse-jardin s'est avérée plus efficace à réduire les gains que les pertes thermiques. RES
... Furthermore, the observed TAS values in this study are relatively lower than those reported in the literature. In Ottawa, Canada, the green roof reduced the membrane temperature fluctuations with a median amplitude of 5-7 • C [60]. Nevertheless, despite the advantages of the expanded drainage layer in the blue-green roof on the outdoor microclimate and substrate-level thermal regime, it is hypothesized that the persistent wet conditions may negatively impact indoor temperatures. ...
... Furthermore, the observed TAS values in this study are relatively lower than those reported in the literature. In Ottawa, Canada, the green roof reduced the membrane temperature fluctuations with a median amplitude of 5-7 °C [60]. Nevertheless, despite the advantages of the expanded drainage layer in the blue-green roof on the outdoor microclimate and substrate-level thermal regime, it is hypothesized that the persistent wet conditions may negatively impact indoor temperatures. ...
... Soil moisture had a low but statistically significant correlation with T 15 and TR 15 but no relationship with T 60 and TR 60 . Soil moisture is believed to be a critical factor in influencing thermal performance, but there have been some conflicting findings in the literature, as Lillian et al. [46] described. ...
Conventional green roofs have been widely accepted as a climate change adaptation strategy. However, little is known about the potential of blue–green roofs and rooftop farms to control urban stormwater and improve microclimates. This study evaluates a farmed blue–green roof’s hydrologic and thermal performance over an entire growing season in Toronto, Ontario, Canada. The runoff discharge from three plots planted with various crops was monitored. The substrate and air temperatures at two elevations of different cultivated and self-sowing plant species were collected and compared to a control roof. Results indicate that planting and harvesting activities impacted the hydrologic performance. Mean values for retention ranged from 85–88%, peak attenuation ranged from 82–85%, and peak delay ranged from 7.7 to 8 h. At the lower elevation, the mean air temperature difference above okra, tobacco, and beet was 2.5 °C, whereas, above squash, potato, and milkweed, it was 1.4 °C. Maximum and moderate air-cooling effects were observed in the afternoon and evening, but a warming effect was observed in the early morning. Farmed blue–green roof evaluated in this study provides a runoff control and microclimate improvement comparable to or better than conventional green roofs, in addition to other benefits such as improving food security.
... Indirect effects impact building surroundings and become realistic only with widespread deployment within a selected urban area such as the reduction of outdoor temperatures or the UHI effect (an elevation of temperature in urban areas relative to the surrounding rural or natural areas due to the high concentration of heat absorbing dark surfaces such rooftops and pavements). Interestingly, this reduction of the UHI effect has a positive feedback effect on building energy efficiency (Besir and Cuce, 2018;Liu and Baskaran, 2003;Saadatian et al., 2013;Xu et al., 2012). ...
... It is well established that green roofs can reduce building energy consumption and improve the comfort levels inside buildings during the spring and summer seasons by reducing and delaying peak temperatures as well as reducing temperature fluctuations (Liu and Baskaran, 2003;Sonne, 2006). The following are a few of the many experimental studies that have found green roofs to reduce roof surfaces temperatures and building heat flux relative to conventional roofs in warm seasons/climates: ...
... With these temperature decreases documented widespread application of green roofs could reduce the UHI effect, which would further lower energy consumption in the urban area (Liu and Baskaran, 2003). For example, Santamouris (2014) (Rosenzweig et al., 2006). ...
With global populations becoming increasingly urbanized, green infrastructure (GI) is progressively being recognized as a sustainable approach to mitigating urban environmental problems. Unlike traditional ‘hard’ engineering approaches that historically viewed problems in isolation and solutions in singular terms, implementation of GI promises some deferment from the effects of urbanization by providing a multitude of benefits such as reduced stormwater runoff and flooding, decreased heat waves, and enlivened local environments and ecological habitats. These benefits are important considering many cities are projected to be more vulnerable to the effects of urbanization with climate change, especially as the vast amount of the global population lives in coastal urban environments. However, the diversity of GI benefits has not been fully characterized, and they are increasingly applied in residential settings. Furthermore, current research has not fully explored the beneficial role of GI in achieving sustainable and resilient communities. Using an Integrated Water: Energy Monitoring System measuring meteorological, water, and energy fluxes over two years (July 2014-June 2016) on a sustainable home in Rockville, Maryland, U.S., the following objectives were explored: (1) Examined how a sloped modular extensive green roof, constructed wetland and bioretention designed in-series affected site hydrology. Furthermore, we studied the effect of season, antecedent substrate water content, storm characteristics (size, intensity, frequency), and vegetation development (green roof only) on hydrological performance. (2) Characterized the seasonal thermal performance of the green roof (to the building and surrounding environment) relative to the cool roof. Evaluated how green roof thermal performance related to evapotranspiration, solar reflectance (albedo) and thermal conductance (U-value). Additionally, the effect of substrate water content, vegetation development, and microclimate on evapotranspiration, albedo and U-values was assessed. (3) Green roof evapotranspiration was measured and compared to values predicted with the FAO-56 Penman-Monteith model. Furthermore, the effects of substrate water content, vegetation characteristics and microclimate on evapotranspiration rates was also evaluated. (4) Finally, using emergy theory, GI sustainability and resilience relative to a gray wastewater system and natural forest was explored.
... This often has a secondary effect on the poor environmental performance of buildings, especially in urban areas, contributing to outdoor 1 3 anthropogenic warming (Rizwan et al. 2008). More recently, there has been a considerable interest in passive methods of indoor temperature regulation, one of which is the use of vegetated roofs (Liu and Baskaran 2003;Jaffal et al. 2012;Lin et al. 2013). This method has the potential for being one of the most cost-effective for temperature moderation, of particular interest in the developing world (Peng and Jim 2015). ...
... A number of benefits have been claimed for vegetated roofs to mitigate some of the negative effects of urbanisation (Ismail et al. 2008;Kamarulzaman et al. 2014). These benefits fall into three main study areas, namely the ability to replicate natural stormwater performance in terms of hydraulic patterns and water quality (Carter and Jackson 2006;Kohler 2006;Dunnett et al. 2008;MacIvor and Lundholm 2011); the restoration of biodiversity (Dunnett et al. 2008;MacIvor and Lundholm 2011;Dvorak and Volder 2010); and the moderation of temperature through shading, improvement in insulation, and evapotranspiration (Liu and Baskaran 2003). ...
... The effect of a green roof in moderating temperature has been studied in relation to two phenomena: in mitigating the urban heat island effect by adapting the external surface temperature of a roof and the air temperature directly above it (Alexandri and Jones 2008;Ayata et al. 2011;Gunawardena et al. 2017); and in improving indoor comfort levels (Jaffal et al. 2012;Castleton et al. 2010). One area of particular interest in both of these groups of studies relates to reduction in energy demand, by reducing the ambient temperature of cities (Alexandri and Jones 2008;Lin et al. 2013;van Hooff et al. 2016) and through reduction in space heating and cooling (Liu 2002;Liu and Baskaran 2003;Theodosiou et al. 2014). All of the studies reviewed show that a vegetated roof outperforms a conventional roof in terms of mitigation of the urban heat island and in improving indoor temperatures. ...
Green roofs have been shown to improve comfort levels of rooms directly below them, since they act as insulators; however, global research suggests that the performance of green roofs in attenuating temperature extremes is dependent on local climatic conditions. This study is located in Johannesburg in the South African interior, in a climate that has not previously been researched. Using heat sensors on the exterior and interior, it explores the thermal performance of a scale model of a vegetated roof in comparison with a soil roof devoid of planting and a tile roof during the dry winter season. Four different methods of enclosure were used to simulate various walling conditions. The maximum, minimum and mean temperatures for the upper and under sides of each roof were compared with the ambient temperature. Exterior temperatures for the green roof closely matched ambient temperatures, suggesting that this roof type would help in minimising the urban heat island effect. The soil roof returned the highest minimum temperatures, thereby achieving the best thermal comfort levels at night; however, this roofing solution is not recommended since the exterior maximum temperatures were considerably higher than the ambient temperature. However, the interior under the green roof has a minimal improvement on ambient temperatures and well below the recommended minimum interior temperature of 19 °C promoted by SANS10400-XA. This study forms part of a broader research initiative into energy-efficient low-cost housing solutions.
... Sistema de naturación de azoteas Cinco experiencias exitosas en la Ciudad de Mérida, Yucatán Funciones y efectos de la naturación de azoteas En la figura 3.4 se puede observar la demanda diaria promedio de energía en un espacio con azotea naturada y de uno sin ella durante el verano y la primavera (Liu, 2003). Fuente: Dibujo propio con base en la gráfica original. ...
... Sistema de naturación de azoteas Cinco experiencias exitosas en la Ciudad de Mérida, Yucatán Funciones y efectos de la naturación de azoteas En un periodo de 24 horas la temperatura en un sistema tradicional de azotea fluctúa 45°C, mientras que en un sistema de azotea naturada se reducen las fluctuaciones a 6°C (Liu, 2003), además de que se protege a la membrana impermeable de microdesgarres y de la radiación ultravioleta. ...
La Ciudad de Mérida es una ciudad intermedia (Romero, 2001) con una tasa de crecimiento alta, un alto grado de dinamismo espacial, aumentos en extensión de la superficie urbanizada, modernización de la infraestructura, dispersión urbana, entre otros factores.
Estos cambios se traducen en términos ambientales, en incremento de la contaminación de las aguas, aire y suelos; desarrollo de islas de calor, aumento de la ventilación y de la concentración de humedad; congestión vehicular; de la segregación socio espacial de sus habitantes y la reducción y fragmentación de áreas verdes.
... Field study in Canada shows that green roof reduces cooling energy by 75% as compared to typical insulated roof. As shown in Figure 10, green roof can act as a good insulation system because heat flux before insulation layer decreases by almost 35 W/m 2 (Liu & Baskaran, 2003). These characteristics are less dependent in plant species but it is best to consider local plants first. ...
... See Figure 11. (Liu & Baskaran, 2003). To cut-down extensive green roof's weight, climbing-plant panel is an option that can be used as roof or wall surfaces. ...
Under current energy and environmental concerns, buildings are targeted as problems required immediatesolutions. Generally, buildings consume plenty of resources, produce unwanted wastes, and sometimes demoteIndoor Environmental Quality (IEQ). Given these negative impacts, Green Building was introduced as ananswer to mitigate the current energy and environmental problems. Architects, engineers, and practitionersquickly adopt this green building idea but the direction was both diversified and unclear. At that time, proclaimedgreen building seems to be just promise lacking of solid evidences. Energy & Environmental rating systemwas initially proposed as a campaign attempting to quantify green buildings. Different measures were takenand then weighted for scoring purposes. Using these scores, green buildings are possible to be quantifiedand ranked afterward. In this review article, not only the rating systems, i.e. BREEAM, Green Star, and GreenGlobe, TEEAM, will be overviewed, but also LEED, the most dominating system in US, will be discussedin detail. The simplicity by having six sustainability measures including sustainable site, water efficiency,energy and atmosphere, material and resources, IEQ, and innovation in design, are the key success of LEEDrating system. Moreover, the flexibility of having different compliance methods and scoring options makes manydesigners are in favor of this approach. By using performance-base compliance method, designers can comparetheir design against the base case for winning the higher performances such as energy cost. The score willthen be interpolated and given by exceeding performances. In order to obtain high scores, practices andtechnologies that are acknowledged by rating systems, particularly LEED, should be systematically strategized.Xeriscaping, Green Roof, Geothermal Cooling, Displacement Ventilation, and Demand Control Ventilation, arethe examples of such technologies that greatly promote the scores across multiple categories. By reviewingcompositions, mechanism, practice, and technologies of green building rating systems, this article should bea useful source for practitioners who will or already involve in any green building project and looking forwardto quantify their buildings with any rating system in the near future.
... In this situation, -Rooftop Gardens‖ and -Green Roofs‖ (roofs with a vegetated surface and substrate) can be a potential alternative remedy to reverse the problem through applying this green technology on contemporary buildings in Dhaka city [11]. Green roofs improve the energy efficiency of buildings through a combination of shading, evaporative cooling and insulation from both green roof plants and growing substrate and the thermal effects of the growing substrate [8]. This reduces the energy demand for space conditioning significantly in spring and summer. ...
... Daily temperature fluctuations cause thermal stresses in materials and decrease their durability. Green roofs minimize temperature fluctuations by creating a barrier between solar radiation and structural layer [8]. ...
Dhaka, the capital of Bangladesh, is becoming exclusively urbanized day by day with an extreme environment. Rapid and unplanned urbanization is making the residential environment unsuitable for living. Application of greeneries in the prevailing infrastructures may be an effective option to minimize the problem. Therefore, the experiment was conducted in Dhaka, Bangladesh to observe the thermal performance of Rooftop Gardens in residential buildings. The data were recorded through two-way approach i.e., quantitatively and qualitatively. The quantitative data (Temperature and humidity) were measured both outdoor and indoor during the warmest week of the year (24th-30th April, 2016) in the roof garden over the four storied academic building of Sher-e-Bangla Agricultural University. Qualitative data were collected by questionnaire survey from the selected forty rooftop gardens of Mohammadpur and Dhanmondi metropolitan area of Dhaka city. The experimental analysis of thermal performance resulted that the average roof air temperature is reduced by 5.2°C with roof garden while average room temperature is reduced by 1.7°C with roof garden compared to bare roof in the diurnal period. Moreover, the temperature of the residence with roof garden stayed near the thermal comfort zone on maximum hour of the day. In the survey result, 60% of the respondents were found to stay within thermal comfort zone which was positively correlated to the vegetation coverage of that roof. Hence, green application on residential building is more appropriate into the contemporary building as a thermal comfort strategy for a climate smart urban planning of Dhaka city.
... In light of the declining energy resources concurrent with escalating energy costs, their effect on energy consumption and environmental control is very important. Therefore, when it concerns the roofing component of the building envelope the current and still most effective way of reducing the building energy demand remains to be the effective use of insulating materials, however alternative approaches including green rooftops, reflective rooftops "cool roofs," smart buildings, and others have shown promise as supplementary methods of reducing energy consumption [3][4][5]. As far as codification systems for building construction most countries have relatively developed codes in terms of envelope performance insulating targets [6]. ...
... The effectiveness of emissivity in Northern climates is contentious as the number of cooling days is typically lower and the low emissivity membranes could be considered to be increasing the cooling load. During peak solar radiation in the summer, the outer surface temperature of an average emissivity membrane can easily reach 50 to 60 • C (122 to 140 • F [3]). Due to the transient nature of solar radiation, the assembly profile probably does not reach a steady-state with these elevated surface temperatures. ...
In the thermal design of low sloped roofing assemblies, two parameters are overlooked, one is the surface temperature of the roof assemblies which provides the required temperature gradient for heat flow, and the other is the mean operating temperature of the roof assembly, which has direct implications on the thermal performance of the insulation. An in situ field study was conducted in collaboration with Alberta Roofing Contractors Association (ARCA) on their headquarters building located in Calgary, to generate data on the mean operating temperature of the roof assemblies and to determine whether the thermal design of roofing assemblies using conventional methods is an accurate portrayal of in-service thermal performance. For the present study, two roof assemblies insulated with polyisocyanurate insulation, one with a white reflective roof membrane and the other with the black membrane were selected and instrumented. During the monitoring period, the mean operating temperature (MOT) of the roof assembly whether it is calculated as the average of interior and exterior ambient (MOTAIR,) or the average of surface temperatures (MOTSurface), was found to be below 24 °C (75 °F), which opposes the current roof thermal designs that are being designed using label R-value (thermal resistance) of the insulation reported at the mean temperature of 24 °C (75 °F) rather than temperature-dependent thermal resistance. The comparison of two energy transfer theoretical models, QConvention and QMOT, with the measured data indicated that the conventional approach of roof thermal design underestimates the energy performance of the roof assembly on average by 30%. The use of roof surface temperatures and the corresponding temperature-dependent thermal resistance of the insulation as in QMOT has been demonstrated to improve predictions of the energy performance. In addition the loss in thermal resistance due to blowing agent diffusion in polyisocyanurate was evaluated after two years of in situ installation.
... Green roofs can improve shading, insulation, evapotranspiration and thermal mass [33] so, they allow buildings to be more sustainable in terms of energy efficiency [34]. Rooftops become very hot in the summer, for this reason, the National Research Council of Canada showed that an extensive green roof with grass reduced the heat flow through the roof by over 75% in the spring and summer in Ottawa [33]. ...
... Green roofs can improve shading, insulation, evapotranspiration and thermal mass [33] so, they allow buildings to be more sustainable in terms of energy efficiency [34]. Rooftops become very hot in the summer, for this reason, the National Research Council of Canada showed that an extensive green roof with grass reduced the heat flow through the roof by over 75% in the spring and summer in Ottawa [33]. Also, green roofs can reflect up to 30% of solar radiation and absorb 60% due to plants' photosynthesis [35]. ...
Green infrastructure has received increasing attention in urban strategies in a sustainable and resilience context, since greenspaces provide diverse ecosystem services. Green roofs can be a form of compensating the loss of ecosystem services and biodiversity in urban areas, contribute to safe access to greenspaces, which is important in times of social isolation, due to viral pandemics, and can guarantee self-reliance food. Thus, this urban measure should be integrated in urban planning and management, by using urban indicators associated with citizens access to greenspaces. Hence, we study pedestrian accessibility to green areas and propose an urban solution to improve access to greenspaces. The assessment is developed using indicators related to the citizens living in the surroundings of green areas and the residential buildings that exist in these areas; the residents living in potential green buildings or blocks with private green roofs and the potential green buildings with private green roofs. The ideal standard distances were considered to analyze the proximity of green areas to the dwellings of residents. We used GIS for the assessment of distances over the pedestrian network. The results indicate the necessity of building green roofs through the private sector. The developed indicators provide an important contribution to the municipal management in the definition of criteria for the urban location of green roofs to promote better access to ecosystem services.
... Also green roof significantly moderated the heat flow through the roofing system and reduced the average daily energy demand for space conditioning due to the heat flow through the roof in the summer by more than 75%. (Liu & Baskaran, 2003).. There is a big gap in constructing green buildings especially in Oman and this could be due to several factors. ...
... Top Roof Garden is the type roof which will be provided in this green building project and that because of top roof garden has shown high thermal performance comparing with normal concrete roof. As the researchers (Liu &Baskaran, 2003) proved that green roof significantly moderated the heat flow through the roofing system and reduced the average daily energy demand for space conditioning due to the heat flow through the roof in the summer by more than 75%. ...
Green building or sustainable building is an ecofriendly concept established by civil engineers to increase the efficiency of
buildings in terms of energy, water, and materials, over the entire life cycle of the building. This study is aimed to develop a sustainable
building at Al-Hail(Oman)with high energy efficiency and lower cost. Considering the wind and solar directions plan was selected.
Based on the selection of materials and method, two proposals were considered for the simulation in Revit 2016 software [Proposal 1
(Green Roof + Double Glazed Windows + AAC Blocks + Terrazzo tiles) and Proposal 2 (Normal Roof + Single Glazed Windows +
Hollow Blocks + Oman Marble)] were compared.The parameters identified were cost, thermal properties and U-values of the materials
for the building.It was observed that estimated energy used in Proposal 1 due to air conditioning reduced 62% than Proposal 2 because
of selected materials with high thermal resistance performance. The study enlighten the facts of conservation of energy by utilizing the
available resources with minimum cost
... These installations serve, beside aesthetical aspects such as providing a green view for residents, energy consumption reduction, as well as multiple environmental benefits. The thermal effects of green roofs, acting as an additional building envelop layer, on energy consumption of buildings have been proven in the building sector by numerous previous research studies [14][15][16]. For example, Wong N.H. et al. [17] conducted a field experiment in Singapore which indicated that the application of green roofs (e.g., rooftop garden) can save from 0.6-14.5% of the annual energy consumption. ...
... Many studies have implemented field measurements to collect field data on the greenery models to compute physics-based energy balance models and to validate the accuracy of the model [15,20,22,26]. The design and construction of experiments for simultaneously collecting weather conditions as well as the temperature of the solid surfaces (e.g., plants, concrete) is a challenging process, which requires a robust and flexible system for real-time monitoring support. ...
The usage of greenery systems as nature-based solutions to assist in urban cooling in summer time as well as urban warming in wintertime is considered a scientific validated approach in urban planning. The objective of this research is the investigation and quantification of the role of green roofs and green facade solutions concerning thermal behavior in buildings energy savings by using standardized semantic city models that allow the quantification of such measures on district and city scales. The implemented model uses standardized geospatial data based on the CityGML format, a semantic city model standard, for analysis and data storage. For storage of the thermal properties of the buildings, the behavior of its occupants as well as the sensor measurements the Energy ADE of the CityGML standard was used. A green roof/façades model was implemented to simulate the heat transfer in a building based on the heat balance principle of foliage, soil, and structural layers. This model allows analyzing the thermal influence of plant and substrate layers on the heat gains from incoming solar radiation into buildings and the heat losses. This implementation was validated for cooling solutions using monitoring data from real-time experiments during summer measurements at three locations in Germany. Results from this experiment correspond well with the findings of other relevant studies. A sensitivity analysis was conducted to test the impacts of climate, substrate and plants on the greenery layer performance.
... Sistema de naturación de azoteas Cinco experiencias exitosas en la Ciudad de Mérida, Yucatán Funciones y efectos de la naturación de azoteas En la figura 3.4 se puede observar la demanda diaria promedio de energía en un espacio con azotea naturada y de uno sin ella durante el verano y la primavera (Liu, 2003). Fuente: Dibujo propio con base en la gráfica original. ...
... Sistema de naturación de azoteas Cinco experiencias exitosas en la Ciudad de Mérida, Yucatán Funciones y efectos de la naturación de azoteas En un periodo de 24 horas la temperatura en un sistema tradicional de azotea fluctúa 45°C, mientras que en un sistema de azotea naturada se reducen las fluctuaciones a 6°C (Liu, 2003), además de que se protege a la membrana impermeable de microdesgarres y de la radiación ultravioleta. ...
... Irrespective of rooftop moisture content, they can also modify the albedo to a certain extent. The surface of a rooftop with a vegetative layer can participate in cooling the ambient air, particularly on hot days, during daytime (Vandermeulen et al., 2011;Liu and Baskaran, 2003). ...
This study investigated the effect of urbanisation on the occurrence of UHI in Kano Metropolis. Data utilised in this study includes; temperature records for the period of 1980 – 2015 for the urban city centre and 1985 – 2015 for the sub-urban city centre, sourced from the Nigerian Meteorological Agency (NIMET) and Department of Geography, Bayero University, Kano respectively. Landsat images of the study areas for the years of 1986, 1998, 2006 and 2016 sourced from the archives of the United States Geological Survey (USGS), and information on the impact of UHI on the livelihood of the people in the study area was sourced through the questionnaires. The Temperature Deviation Index (TDI) was used in analysing the trends of temperature distribution in the study area and the combination chart was used in comparing the temperature data of the urban and sub-urban city centres. Land Surface Temperature (LST) maps as well as the Land Use/Land Cover (LULC) maps of the study area for the years of 1986, 1996, 2006 and 2016 were estimated using Model Maker in Earth Resource Data Analysis System (ERDAS) Imagine 14 software. Results obtained showed that temperature distributions has been on the increase for both the urban and sub-urban city centres at an annual increasing trend of 0.054°C and 0.021°C respectively, with that of the urban city centre being faster than that of the sub-urban centres. The urban city centre exhibit higher atmospheric and surface temperatures compared to its sub-urban counterpart thus, indicating the presence of both Atmospheric and Surface UHIs in Kano Metropolis. The regression analysis between the built-up areas and the high LST values showed that urbanisation account for 80.5% increase in the LST of Kano Metropolis, thus indicating a very strong positive relationship between urbanisation and UHI. The residents are affected by UHI negatively on their health, environment, water-supply consistency, power consumption and economic activities. The study concluded that urbanisation has been the major factor leading to the occurrence of surface and atmospheric UHI in Kano Metropolis. The study recommended massive afforestation programmes, adoption of green and cool roofing technologies, proper spacing between houses, and accommodation of green areas and open spaces into cities physical plans due to their cooling potentials as some of the ways of adapting and mitigating to the impacts of UHI.
... A green roof, i.e., a roof with a vegetative cover, is one passive technique that can be used to address environmental issues in an urban setting. Researchers have shown that green roofs can be used to mitigate problems associated with storm water runoff, the urban heat island effect, wildlife habitats, and air and water quality [13,[21][22][23]. ...
Green roofs provide various ecosystem services, including habitats for diverse organisms in urban areas where natural space is very scarce. This study aims to evaluate the restoration effects of green roofs created by applying an ecological restoration method to reinforce habitat function. The reference ecosystem selected for the ecological restoration of a roof was a Korean red pine stand established on Mt. Bulam, considering the soil depth, light, moisture conditions, etc., compared with the roof’s environmental conditions. Ecological restoration was carried out by planting two-year-old pine seedlings and scattering surface soil collected from the pine stands. The pine trees showed geometrical growth in height and diameter and a high water-use efficiency. The ecological restoration of the green roofs demonstrated an ecological function for improving the urban climate through the mitigation of the urban heat island effect and high productivity, showing different functions depending on the greening method. The composition and diversity of vegetation and insects at the ecological restoration site were similar to those at the reference site, whereas the landscape architecture sites, which were created using the landscape architecture method, were different from the reference site. These results confirm that applying the ecological restoration method for rooftop greening resulted in better biological habitat function than applying existing landscape architecture methods.
... The selection of appropriate roofs for green roof installations is mostly dependent on the inherent properties of the roof surface. Several rules in existence in various countries, such as those created in Ottawa, Canada [38], Munich, Germany [39], and Linz, Austria [40], require a minimum surface area of at least 100 m 2 for green roof implementation. This criterion of acceptable minimum area is developed to ensure an environment suitable to the diverse growth of plant species. ...
In the 21st century, tackling climate change is an important challenge, and the absorption of CO 2 via urban greening employing photosynthesis offers a potential answer to the climate issue. Within this work, the city of Nador is chosen as a case study. The initiative in question proposes an enhanced technique focused on estimating the advantages of urban greening in terms of carbon storage and sequestration. This technique combines the use of Geographic Information Systems (GIS) tools and the InVEST model, enabling the study of land use and land cover (LULC) scenarios within the location. These scenarios contain numerous alternatives, ranging from the adoption of intense and extensive green roofs to the establishment of gardens and woodland areas. The carbon storage modeling technique depends on the exploitation of land use maps, reinforced by a bibliographic examination of the key carbon reservoirs. The analysis of results from biophysical modeling indicates a considerable increase of over 45.36 % compared to the existing condition when the option of extensive green roofs is chosen. In the setting of extensive green roofs, this rise reaches a rate of 64.20 %. Furthermore, the restoration of the Gourougou forest north of the city leads to an increase of 70.30 %. The adoption of diverse combinations, such as the integration of green roofs with urban vegetation, greatly helps to further enhancing carbon storage. From a financial perspective, the additional value can range from 3,601,025.53, depending on the chosen scenario. This financial assessment highlights the possible advantages that might be converted into carbon credits in return for emission reduction, partially offsetting the expenses associated with the adoption of each greening solution. Ultimately, these findings give a chance for urban planners and green architecture professionals to perform in-depth planning analyses.
... In this study the majority of vegetated treatments provided greater temperature reduction, water retention, and nitrate retention relative to the substrate only control. This is in line with previous research demonstrating the benefits vegetation provides to the green roof system [45][46][47]. Many treatments performed equivalently to the commonly used green roof species Sedum acre, suggesting that lawn plant species can be used to create a functional green roof in Nova Scotia. ...
... Usually, costs vary depending on the growing medium, type of roofing membrane, quantity of plants and drainage system [6]. Nevertheless, cost is not a disadvantage as green roofs reduce thermal gain from plant shading, increase thermal insulation, and acoustical insulation, which cool air and surface temperatures, all of which decreases depending on HVAC system for building interiors [18,19]. ...
... Many studies have supported that the presence of planted areas increases people's comfort (Kaplan and Kaplan, 1989;Ulrich et al., 1991;Ulrich, 1998;Bass and Baskaran, 2003). Roof gardens increase the quality of space with their presence in the building environment, providing users with green space and recreation opportunities (Pouya, 2019) physical and social (Wang and Pryor, 2019); economic (Lazzarin, Castellotti and Busato, 2005;Acks, 2006;Peck et al., 1999), psychological (Herzog, Maguire and Nebel, 2003;Laumann, Gärling and Stormark, 2003), and physiological (Tooke et al., 2011;Knaus and Haase, 2020;Wong et al., 2003;Köhler et al., 2002;Sailor, 1995) benefits (Oberndorfer, 2007;Wang and Pryor, 2019;Davis, 2011;Dunnet, 2006;Yuen and Hien, 2005;Liu and Baskaran, 2003). They increase the aesthetic values and land values of their environment, biodiversity (Brenneisen, 2003;Gedge, 2003;Brebbia, 2017) and food production in urban environments (Jafari et al., 2015;Dorr et al., 2017;Sanye-Mengual et al., 2015). ...
The aim of this study is to create a checklist of roof garden design criteria. This scope of work includes an encompassing review of international standards studies such as German Landscape Research, Development, and Construction Society; the American Society for Testing and Materials; the U.S. Green Building Counci; and Green Roofs for Healthy Cities, whereas the generated checklist was evaluated in the Marmara Forum Mall. As a result of the study, an answer was sought to the question, “What are the prerequisites for a roof garden serving the needs of users in today's conditions?” whereas on-site detection, observation, and photography were used as working methods. As a result, in considering the evaluation of the checklist on a scale of the Marmara Forum Mall, climatic data, activities with its hard structure, promenade areas, and designs of plantlife and water elements in soft structure are moderately sufficient, whereas it was determined there is no problem in the roof furniture design and maintenance.
... In addition, green roofs reduce indoor temperatures through transpiration. [4] Green roofs not only can affect the building heat gain and loss, but also the reflected heat in the surrounding, humidity and air quality. They have a great role in creating microclimates. ...
Green roofs and walls are a rising technology in the global sustainable architectural industry. The idea takes great steps towards the future of sustainable design due to its many benefits. However, there are many barriers and constraints. Economical, structural, and knowledge barriers prevent the spread of the usage of green roofs and living walls. Understanding the benefits and expanding them will spread the idea. Benefits provided by these green spots interrupt and maintain the current urban cover. Food production is one of the benefits of green roofs. It can save money and energy spent in food transportation. The goal of this paper is to put a better understanding of implementing green systems. The paper aims to identify gains versus challenges facing the technology. It surveys with case studies buildings with green roofs and walls used for food production.
... The roof of the building complex is covered by grass with aims to create a public green place in a post-industrial area with an integrated system of land slopes and natural diversity of terrain. Such green roofing system is usually applied for energy savings by decreasing the demand for space conditioning and can help in mitigation of urban heat island effect, in the improvement of air pollution, water management, an increase of sound insulation, air humidity and its circulation, and ecological preservation (Liu & Baskaran, 2003;Berardi et al., 2014). Especially in summer, plants shade the substrate, resulting in less sunlight reaching it therefore this decreases both the absorption and the subsequent heat release. ...
The localization of Surface Urban Heat Island (SUHI) as a potential heat risk for the urban population was evaluated. The paper aimed to propose an approach to quantify and localize (SUHI) based on Landsat series TM, ETM+, OLI satellite imageries from the period 1996-2018 and recognize the Atmospheric Urban Heat Island (AUHI) effects from long term temperature measurements. Using the theoretical relation between the Normalized Difference Built-up Index (NDBI), the Normalized Difference Vegetation Index (NDVI) and the LST (Land Surface Temperature), SUHI intensity and SUHI risk maps were created from the combination of LST, NDVI, NDBI using threshold values to localize urban heat island in the Katowice conurbation. Negative values of SUHI intensity characterize areas where there is no vegetation, highly built-up areas, and areas with high surface temperatures. The urban grow-revealed from SUHI-and global climate change are acting together to strengthen the global AUHI effect in the region as the temperature measurements were indicated.
... The research analyses the contribution of such renovation project, in terms of mitigation solutions, those related to green envelopes in buildings: green roofs and green walls. According to related research studies on green roofs, the energy required for space conditioning due to the heat flow through the green roof, would be reduced by more than 75% [14]. In addition, green walls contribute significantly to the reduction of indoor air temperature in the summer, by reducing the external air temperature of a west-facing orientation up to 4º C on a clear August day in Japan [15] and by 5º C in South Africa [16]. ...
... The research analyses the contribution of such renovation project, in terms of mitigation solutions, those related to green envelopes in buildings: green roofs and green walls. According to related research studies on green roofs, the energy required for space conditioning due to the heat flow through the green roof, would be reduced by more than 75% [14]. In addition, green walls contribute significantly to the reduction of indoor air temperature in the summer, by reducing the external air temperature of a west-facing orientation up to 4º C on a clear August day in Japan [15] and by 5º C in South Africa [16]. ...
... In these cases, thermal performance is determined by: roof shading; evaporative cooling due to the presence of plants and of substratum of cultivation; and additional insulation levels of plants, caused by their substratum of cultivation and by the thermal mass of the soil [53]. Moreover, the energy benefits that can be obtained through the implementation of green roofs are also influenced by the local climate [22], by the morphology of the green roof, and by the technological components constituting the building. ...
This paper deals with the interactions between biophysical and microclimatic factors on the one hand with, on the other, the urban morphology of intermediate urban open spaces, the relationship between environmental and bioclimatic thermal comfort, and the implementation of innovative materials and the use of greenery, aimed at the users' well-being. In particular, the thermal comfort of the open spaces of the consolidated fabrics of the city of Rome is studied, by carrying out simulations of cooling strategies relating to two scenarios applied to Piazza Bainsizza. The first scenario involves the use of cool materials for roofs, cladding surfaces, and pavement, while the second scenario, in addition to the cool materials employed in the first scenario, also includes the use of greenery and permeable green surfaces. The research was performed using summer and winter microclimatic simulations of the CFD (ENVI-met v. 3.1) type, in order to determine the different influences of the materials with cold colors, trees, and vegetated surfaces on the thermal comfort of the urban morphology itself. Meanwhile, the comfort assessment was determined through the physiological equivalent temperature (PET) calculated with the RayMan program. The first scenario, with the use of cool materials, improves summer conditions and reduces the urban heat island effect but does not eliminate thermal discomfort due to the lack of shaded surfaces and vegetation. The second scenario, where material renovations is matched with vegetation improvements, has a slightly bad effect on winter conditions but drastically ameliorates the summer situation, both for direct users and, thanks to the strong reduction of the urban heat island effect, to urban inhabitants as a whole.
... Also, the transpiration of the vegetation on green roofs provides an evaporative cooling effect that can lower the air temperature locally to below ambient temperatures, helping to reduce the urban heat island effect globally. (Hopper 2007, Liu and Baskaran 2003, Feng and Hewage 2014 ...
... Green roofs reduce cooling and heating loads for the floors immediately beneath the roof [19] and [20] and some particulate atmospheric pollutants are adsorbed, while greenhouse gases as well as other gaseous pollutants are absorbed [21], CO 2 being removed through photosynthesis. Biodiversity improvements are indisputable compared with conventional roofs. ...
... Different strategies exist to protect the building from sun heat loads such as shading devices [3][4][5][6], surrounding vegetation [7][8][9], angular and spectral selective coatings [10][11][12][13][14][15][16][17][18] and double-skin facades or roofs [19][20][21][22]. Other technical solutions exist to exploit cooling from the environment, such as night sky cooling systems [23][24][25][26][27], natural ventilation [3,26,[28][29][30][31] and ground cooling [32][33][34]. ...
... Consequently, it is possible to assert that a green roof can enhance the thermal inertia of a roof, thus increasing the internal comfort, reducing energy needs [13][14][15][16][17][18][19]. In addition, if installed in high-density urban areas, a green roof can offer positive contribution against the UHI phenomenon, also absorbing polluting gases. ...
In the building sector, both passive and active systems are essential for achieving
a high-energy performance. Considering passive solutions, green roofs represent a sustainable
answer, allowing buildings to reach energy savings, and also reducing the collateral effect of the Urban
Heat Island (UHI) phenomenon. In this study, a roof-lawn system was investigated by means of
an extended measurement campaign, monitoring the heat transfer across the roof. Heat-flow meters
and air- and surface-temperature probes were applied in a real building, in order to compare
the performance of the roof-lawn system with a conventional roof. This experimental approach
was followed to quantify the different thermal behaviors of the building components. Moreover,
an equivalent thermal model of the roof-lawn system was studied, in order to obtain the equivalent
thermal properties of the roof, useful for setting building models for yearly energy simulations.
The roof-lawn system revealed its advantages, showing a higher thermal inertia with no overheating in
summertime and a lower thermal transmittance with energy savings in wintertime, and, consequently,
better indoor conditions for the occupants of the building.
... A plant canopy and the growing substrate help shield traditional bituminous roofing membranes from ultraviolet radiation and wide day-night temperature fluctuations. For example, a study conducted in Toronto, Canada reported the membrane temperature on a convention roof reached 70°C (158°F) in the afternoon, whereas the roof membrane under the green roof was only 25°C (77°F) (Liu and Baskaran, 2003). The daily expansion and contraction of the roofing membrane due to swings in day-night temperatures stress the membrane, resulting in fatigue and eventual failure. ...
... The roof of the building is alone responsible for 70% of its heat exchange, thereby increasing heating and cooling load. Widely used bituminous roofs can reach temperatures as high as 60-70°C during summer, thus significantly increasing the cooling load (Liu and Baskaran, 2003;Teemusk and Mander, 2009). Several studies have been done on PCMs modified roofs and walls to minimize the undesirable heat exchange. ...
Many phase change materials (PCMs) experience a change in transparency when undergoing a phase transition. These thermo-optically responsive materials can be used to generate passive temperature control systems for building enclosures. The integration of optical and thermal switches into smart temperature-controlling elements requires rationally designed PCMs featuring tunable optical and thermal properties. Two polymers, poly (Octadecyl methacrylate) (PSMA) and poly(2-(2-(octadecyloxy) ethoxy) ethyl methacrylate) (PE2SMA) were synthesized and evaluated for their potential use in passive thermal energy storage systems. UV-Visible Spectroscopy, Near Infra-Red Spectroscopy, and Differential Scanning Calorimetry were used to evaluate the effect that changes in the polymer chemical structure had on the optical and thermal properties of the resulting materials. Insertion of a 6-atom flexible spacer (diethylene glycol) between the pendant crystalline motif and the polymer backbone of PSMA resulted in increases of latent heat storage capacity from 62 J/g to 94 J/g and thermal conductivity from 0.218 W/mK to 0.318 W/mK. Notably, insertion of a flexible spacer also resulted in a melting transition temperature increase from 37.7 °C for PSMA to 48 °C for PE2SMA. The visible transmittance of the polymers increased from 0% to 90% upon transition from crystalline to amorphous state. This study presents a synthetic strategy to control thermal and optical properties of polymeric PCMs materials. The material properties and structure-property relationships derived from this study will enable the refinement of the models used to predict the performance of passive temperature-regulating systems. More accurate models will guide the development of the thermo-responsive polymeric materials required for better perfoming temperature-regulating building enclosures.
... It noted that a 0.6 • C increase in ambient temperature would increase the cooling peak demand from 1.5% to 2%. The National Research Council of Canada (NRCC) studied, analyzed and compared a typical extensive green roof with a conventional roof in Ottawa [37]. The results showed that the green roof reduced the heat flow through the roof in summer considerably more than in winter. ...
A comprehensive parametric analysis was conducted to evaluate the influence of the green roof design parameters on the thermal or energy performance of a secondary school building in four distinctively different climate zones in North America (i.e., Toronto, ON, Canada; Vancouver, BC, Canada; Las Vegas, NV, USA and Miami, FL, USA). Soil moisture content, soil thermal properties, leaf area index, plant height, leaf albedo, thermal insulation thickness and soil thickness were used as design variables. Optimal parameters of green roofs were found to be functionally related to meteorological conditions in each city. In terms of energy savings, the results showed that the light-weight substrate had better thermal performance for the uninsulated green roof. Additionally, the recommended soil thickness and leaf area index for all four cities were 15 cm and 5 respectively. The optimal plant height for the cooling dominated climates is 30 cm and for the heating dominated cities is 10 cm. The plant albedo had the least impact on the energy consumption while it was effective in mitigating the heat island effect. Finally, unlike the cooling load, which was largely influenced by the substrate and vegetation, the heating load was considerably affected by the thermal insulation instead of green roof design parameters.
... Research carried out by [13] confirms that green roofs reduce the heat flow through the roof and thus reduce the energy demand for air conditioning of the building, and thus also reduce the effects of UHI in the building, but this is a separate issue related to the supply and consumption of energy in the building. ...
In the era of developing cities, it is extremely important to maintain an appropriate level of quality of the surrounding environment or to improve this level. Newly built buildings are not without impact on the city's environment. It is important to control and limit their negative impact. Multi-criteria investment assessment systems help with many problems related to urban development. They allow analysis and evaluation of various issues, including those related to the environment. The purpose of this study was to determine the spatial structure of buildings certified in the BREEAM system (Building Research Establishment Environmental Assessment Method) in Kraków by developing a map of their deployment, and then analysing the location of green buildings in terms of selected environmental issues. The selected certification system is one of the most commonly used multi-criteria assessment systems in Poland. The map was developed to assess the current spatial structure of green buildings. On the basis of the map, it is possible to indicate potential areas of the city where it would be advisable to locate a green building that meets specific environmental requirements. In Kraków, it can be noticed that objects with the In-Use certificate are mostly available individually. There are only two small clusters of such buildings. Upon analysing buildings with a final certificate, it can be observed that there are both single buildings as well as small and larger clusters (office parks). These facilities are located near or between the beltways. When analysing the distribution of buildings with the certificate obtained at the design stage, it can be observed that most of them are located near bypasses. Two clusters are located in the southern part of the city, but this is due to the expansion of existing office parks. Comparing the developed map with the location of the combined sewerage system in Kraków, it can be seen that the vast majority of certified facilities are within or in close proximity to the combined network. If in these facilities solutions related to the management of rainwater at the place of precipitation were used, each of them represents a significant relief for the sewage system in Kraków. Due to the fact that some of the green buildings in Kraków are present in clusters, their fulfilment of requirements related to the introduction of greenery to the plot (Land Use and Ecology, Surface water run - off and Flood risk categories) may affect the levelling of the urban island heat in the areas where they occur. Most green buildings in Kraków are located along the city's three bypasses. If these buildings have scored points in the category of Transport for specific activities, then in combination with their location this represents a positive value for the city's air quality. Among the requirements for green buildings in multi-criteria assessment systems are those whose fulfilment is a particular value for the city's environment only with a specific location of the building. For this reason, it matters to the city whether the newly constructed buildings are green. The most common positive effects can be expected in the central parts of cities, because that is where the combined sewerage system dominates, where there are problems associated with UHI (Urban Heat Island) or urban floods. The presence of several buildings near each other also generates a pro-ecological effect.
... Few studies attempted to reveal the magnitude of energy savings at a building located in a particular climate region with the installation of insulation materials (Balaras et al., 2007;Al-Sanea et al., 2012;Al-Homoud, 2005;Newton et al., 2000). Findings of these studies revealed that the property of materials like thermal mass also influences residential buildings for heat gain-loss due to the variation of atmospheric temperature (Al-Sanea et al., 2012;Liu and Baskaran, 2003;Gregory et al., 2008;Zhu et al., 2009;Al-Sanea and Zedan, 2011;Shaviv et al., 2001). Appropriate retrofit is another preference to recuperate energy conservation of existing residential buildings suggested by some other studies (Ma et al., 2012;Reed and Wilkinson, 2005;Balaras et al., 2000). ...
Electricity dependent heating-cooling (H/C) system has increased rapidly to provide thermal comfort to the occupants. H/C is a major source of energy consumption in residential buildings around the world. Studies revealed that the thermal properties of building materials are converted into the same unit as thermal resistance (R) in the USA, Canada, The UK, Australia, and other countries. However, none of the previous studies have considered the adaptation of national insulation codes to reduce electricity cost and greenhouse gas (GHG) emissions with the correlations of energy consumption (Q) to thermal resistances (R) of the building envelop (A). Therefore, this study attempts to review the optimum energy consumption of a selected house due to H/C at different choices of national code standardized R values. Accurate envelop areas (A) of the selected house components are estimated by applying the Autodesk Revit Building Information Model (BIM) to use in the energy model. The case study critically evaluates the variation of electricity cost, GHG emissions, and selection of the optimized thermostat settings for energy savings in different climatic regions and seasons of a year. Different correlations are obtained using risk analysis software on energy consumptions with code recognized arrays of insulations. This sensitivity analysis result shows that the corelation coefficient of energy consumption with medium-low insulated building envelop (r = 0.44) is more significant than improved, maximum, medium-high, and minimum insulations (r = 0.14–0.29) which indicates the insulation range where more emphasis should be put to get an optimized solution. Thus the developed analytical framework supports inclusive decision-making by selecting appropriate kinds of insulation for the design of a sustainable house.
... Olivieri [28] conducted an experimental study on an extensive green roof situated in the Mediterranean region, in which an equivalent thermal resistance of 6.53 m 2 ·K·W −1 was obtained. Moreover, many field measurements have revealed that green roofs effectively attenuate the daily periodic temperature acting on the surface of the building [29][30][31][32][33][34][35], which is important for the reduction of building peak cooling load. Evaluation indices such as the decrement factor [35,36] were measured to quantify the resistance of green roofs against sol-air temperature fluctuations. ...
This study investigated the thermal characteristics of an extensive green roof under air-conditioned and non-air-conditioned states by using experimental data obtained on successive sunny summer days. Two indices of the green roof, namely the equivalent thermal resistance and the equivalent decrement factor, were estimated through comparison with a common bare roof. Under the non-air-conditioned state, the distribution of the average temperature on the green roof profile was S-sharp. The lowest average temperature of the green roof was observed on the interface between the planting soil and roof structure, which were 1.8 and 0.9 °C below the outdoor and indoor air temperature, respectively. This finding indicated that the bottom of the soil layer functioned as a “cooling source” that absorbed heat from the upside and downside. The indoor critical air temperature that maintains the heat flux equal to zero was investigated on the basis of the experimental data. The influence of indoor critical air temperature on the equivalent thermal resistance was discussed; for the same green roof under the same outdoor climatic conditions, an indoor air temperature that is closer to the indoor critical air temperature yields a higher equivalent thermal resistance. Therefore, the equivalent thermal resistance of the green roof obtained under low indoor air temperature is recommended for practical use.
... Mentens et al. 2006). They can mitigate noise and bind dust and other air pollutants (Oberndorfer et al. 2007), extend the cycle of repair of roof structures beneath them (Getter & Rowe 2006;Liu & Baskaran 2003), cool buildings and the entire urban structure, thus relieving the so-called urban heat island effect that is feared to have adverse health effects also in Finland (e.g. Suomi 2014;Castleton et al. 2010;Näyhä 2007). ...
Green roofs (GRs) have emerged as an essential component for the sustainability of buildings, as they reduce the need for cooling energy by limiting heat transmission into building space. The benefits of implementing GRs are appropriate in tropical regions with hot temperatures. The entire Association of Southeast Asian Nations (ASEAN) is located in a tropical climate and receives about 12 h of sunlight every day throughout the year, which offers excellent opportunities to install GRs. This research reviews the literature on GR knowledge in ASEAN countries over the past decade (2012–2022) and discusses two main points including (i) GR development level status and (ii) GR performance regarding drivers, motivations, and barriers. The review reveals that Singapore and Malaysia are two among ten countries with significant developments in GRs. Barriers to expertise, government regulations, and public awareness of green roofs represent the most challenging aspects of GR implementation in ASEAN countries. Although research regarding the use of green roofs has been conducted widely, ASEAN countries still need to investigate regulatory breakthroughs, incentives, and technology applications to encourage the use of GRs. The review recommends promoting the use of GRs, which have the potential to reduce energy consumption by up to fifty percent, outdoor surface temperature up to 23.8 °C, and room temperature to 14 °C. The use of GRs can also mitigate runoff issues by up to 98.8% to avoid the risk of flooding in ASEAN countries, which have high rainfall. In addition, this review sheds new insights on providing future potential research to improve GR development in the ASEAN region.
The design of a low-rise residential building with an exploited green roof was studied. In order to improve the ecological condition and tourist attractiveness of the building in the city of Odessa, a project of eco-reconstruction of the "Rodokonaki" apartment building with the organization of a flat exploited green roof is proposed. The project involves a combined plan of an exploited roof with combined landscaping and landscaping, and can also be considered as a fifth facade. Using the example of the designed building, it was found that the steppe type of roof landscaping is the most promising for arid Ukrainian regions, in particular, the city of Odessa. It is proposed to place benches made of natural eco-material - wood on the exploited roof; small architectural forms (lamps, urns - also made of eco-wood). Bushes with a stone fence are planted around the perimeter of the roof. Stone paving with a fountain, green spaces and a small children's playground is designed on the territory of the house. The use of ecological finishing materials provides visual comfort and brings people closer to the natural environment. The use of green spaces on the roof ensures not only an increase in the standard of living of citizens, but also improves human health, makes the surrounding urban environment comfortable and close to natural conditions. Energy saving is achieved due to the increased thermal insulation properties of the green roof. Exploited roofs can be additional public spaces, sports areas and meeting places. The main advantages of this solution, structural features, calculated loads on the roof, as well as types of landscaping are analyzed. It has been proven that the principles and methods of "green roof" must be implemented in modern construction to improve the emotional state of residents, urban ecology, and tourism development.
The Urban Heat Island (UHI) phenomenon is commonly solved by implementing materials with optimal thermic and evapotranspiration properties which help decreasing the air temperature in dense urban areas. This approach has been applied in this study, testing six different materials (replacing the current Macadam) in one parking area in Bari (Italy), which provides a large-scale testbed, by means of a thermal three-dimensional non-hydrostatic simulation: impervious asphalt pavement (IAP), asphalt permeable pavement (APP), green pavement (GP), green pavement-asphalt permeable pavement (GP+APP), grey porous concrete blocks (GCB), and light concrete permeable pavement (LCPP). The highest-performance pavements in terms of potential air temperature (PAT) reduction were the GP (−1.22°C), GCB (−1.26°C) and LCPP (−1.22°C), which also showed a constant relative humidity, suggesting their UHI mitigation benefits. A comparison of the structural properties as well as the construction and maintenance costs of such pavements is also provided, finding the best mitigation strategy (GCB).
The evolution of rural to urban areas has a negative impact on the availability of green zones. The lack of space gives green concrete walls the opportunity to introduce vegetated areas in highly urbanized cities. However, cementitious materials are not the best substrate for plants. Still, diverse microbial communities are suitable for colonizing cementitious materials, allowing later introduction of other plants. One of the limiting factors for microbial growth under environmental conditions is the availability of water for the microorganisms. In this study, the bio-receptivity of cementitious materials under laboratory conditions was investigated, studying relevant parameters such as the porosity needed for the colonisation. Superabsorbent polymers (SAPs) were added in order to improve the water retention capacity and the colonisation of cementitious materials. These polymers, crosslinked networks able to absorb fluids up to hundreds of times their own weight, promote bio-receptivity and clear algal growth was observed. Recycled SAPs, obtained from a cleaning and crushing action of hygienic products, may show an added benefit in terms of sustainability and a circular economy. The best results were obtained with a SAP leading to a well-distributed overall macroporosity near the surface.
In the context of urban land-use growth and the consequent impacts on the environment, green spaces provide ecosystem services for human health. The ecosystem services concept synthesises human–environmental interactions through a series of combined components of biodiversity and abiotic elements, linking ecological processes and functions. The concept of green infrastructure (GI) in the urban context emphasises the quality and quantity of urban and peri-urban green spaces and natural areas. In dense urban contexts, the applications of GI are limited and not applied to the potential urban spaces such as roofs and gardens. Often, roofs are characterised by impermeable paved surfaces with negative effects on human well-being, whereas garden designs do not consider social needs and environmental interactions. The role of urban stressors or the urban context as a driving force or pressure of urban green space is not always well understood and employed in the planning of green spaces. This is partly due to a knowledge gap between different science disciplines that operate on different scales, from single processes of the plants (which focus on plant responses to environmental stresses affecting human well-being) to urban ecosystems (which focus on the biodiversity and urban space planning–human well-being relationship). This can create a paradox, as green spaces that are not adequately designed might not produce the expected effects. In this paper, an overview of benefits and limitations of applying the ecosystem services approach when designing green spaces is presented. The focus is on the main urban ecosystem services provided by green roofs and community gardens such as GI that can represent strategies to provide ecological and social multifunctionality to waterproofed surfaces connected to the buildings and low-exploited gardens being the main areas that affect dense urban settlements, and thus, increasing the ecosystem services in the urban environment, such as reducing the Urban Heat Island, as well as flooding events. Specifically, the paper highlights (i) feedback between ecological processes and functions that support ecosystem services, (ii) urban environmental stresses in relation to disservices that these can create for human well-being and (iii) key issues that should be considered in the planning and design of urban ecosystem services. Such a new vision of urban ecosystem services highlights the need to look at GI as an active part of the urban space design in the built environment.
The contribution follows the European guidelines for the adaptation of the built environment to climate change, illustrated at the COP21 (2015) and collected in the European Climate Adaptation Platform. The text concerns requalification process of the urban open spaces by connecting social and technological features characterizing the urban realm and the related environmental-climatic performance. Through an in-depth study of materials and possible combinations of innovative materials, urban vegetation, water elements and urban shades, the current knowledge of the complex issue of outdoor comfort and urban microclimate is being extended to provide innovative social and functional solutions. The paper comprises the relationship between energy use and urban morphology, studies on intermediate urban open spaces, on environmental and bioclimatic comfort, the interactions between biophysical and microclimatic factors, ultimately the tests of innovative technologies.
Three experimental green roofs in Melbourne with depth of 100, 150 and 300 mm have been assessed to quantify their thermal performance. To evaluate the benefit of substrate depth, temperature was recorded every 50 mm along a vertical profile. Green roofs consisted of scoria substrate and a mix of three species of plants: Lomandra longifolia, Dianella admixta and Stypandra glauca. Statistical analyses applying the hierarchical partitioning technique showed that solar radiation is the main driver affecting the green roof surface temperature, air temperature has strong correlations with the variations of the temperatures recorded below the surface, while moisture content has the least influence. Temperature profiles of the green roof show that the first 50 mm do reduce the heat flowing through the green roof substrate regardless the total green roof substrate depth. Differences in thermal performance arise at deeper points, where thicker green roofs are able to delay the change of substrate temperatures. Similar effects were found for the heat fluxes measured at the interface between the green roof and building roof. These results confirmed that green roofs may be used as a sustainable passive technology to reduce building energy consumptions for South-East Australia climate.
The present book reference is unique in the sense that it covers all the possible urban issues along with technological options. The book mainly divided in 5 parts. Part 1 is general in nature which include urban history and conceptual parameters for better understanding of urban attributes whereas part 2 deals with Cities of Tomorrow: 2050, Environmentally sustainable urban planning and Environmental Policy Parameters in Urban Planning. Part 3 include Urban air pollution, Urban Heat Island Effect, Effects of Albedo in Urban Planning, Sustainable Urban Transport, Environmental Sustainability - Global Need of the Day, Urban Atmospheric Conditions- A case study, Urban Automobile Air Pollution - A case study, Urban Municipal Solid Waste - A Case Study, Urban noise pollution, Urban Water Pollution, Green Buildings, and Green Urbanism. Part - 4 deals with Global Environmental Impacts in the form of Climate Change and Global Warming- An Emerging Concern whereas part - 5 deals with Governance.
This thesis presents the evolution of the energy situation in Algeria with a comparison to the
situation prevailing in the United States, Canada and France. A comparative study is carried out in
order to investigate the overall energy consumption by sector and type of energy and the energy
policies that reflect this situation, in order to determine the initiatives that should be taken to
improve the energy efficiency of buildings for both individuals and the public authorities. The
passive energy efficiency measures applied to buildings are being showcased, because these
measures lonely can divide the total energy demands of a building in the local weather data.
The methodology of this work is based on numerical methods by the dynamic thermal simulation
using the simulation software TRNSYS and TRNBuild interface. The result showed that the use of
passive energy efficiency measures: the compactness of the building, the distribution of internal
rooms and efficient windows with permanent sun protection and thermal insulation for the double
wall with hollow brick improves energy efficiency by nearly 𝟐/𝟑, also the use of straw bale as a
building material is the most efficient solution in heating, while the stone allows obtain the
maximum benefit in term of cooling.
Keywords: Energy Efficiency, Energy Requirement, Performance, TRNSYS, Building Simulation.
Various studies have been conducted regarding the heat problem of Libya’s building recently. The current method is to
create a heat barrier in all parts of the building. Thermal insulation R-value of each material and the heat transfer
coefficient such as U-value confirms to the Egyptian standards. This research was conducted by using a new design of
double wall heat insulation materials which are available in Libya. This new design is to be compared to previous
research. The proposed double wall and generated R-value provide higher efficiency than the best efficiency ever done.
This paper aims to evaluate the possibility of using the roofs of habitations in Caruaru city in the semiarid region of Pernambuco, Brazil, for two purposes: as green roofs to mitigate extreme temperatures inside the houses and for rainwater harvesting and storage for potable purposes. For this, a preliminary study was carried out with inside and outside temperature monitoring of rooms with a green roof and conventional roof to verify the thermal variation in a real situation. Furthermore, the potential of rainwater harvesting for Caruaru city was evaluated based on precipitation data provided by the Water National Agency and an estimation of the available roof area (buildings and houses). In this context, two scenarios were analysed: (scenario 1) the whole roof surface was used for rainwater harvesting and saving and (scenario 2) green roofs were implanted in part of the roofs.
The results of this preliminary study indicated that the use of green roofs resulted in lower temperature variations throughout the day, decreased internal temperatures, and decreased thermal amplitude in relation to a conventional roof (with tiles). Regarding the reduction of the catchment area because of the recommended use of green roofs in a semiarid region, considering green roof application just over the bedrooms (which was considered to cover 16 m² in total), the water saving potential of the public supply system decreased, with a monthly average of 23.13% versus 28.43% (without green roofs). Implanting green roofs in part of the roofs of houses, although there is a reduction in the rainwater volume that can be harvested, can result in an increase in thermal comfort, whereas this is not feasible with the use of the entire roof area to harvest potable water. Thereby, the results indicate that the simultaneous use of the two kinds of roofs (conventional and green) is feasible even in a semiarid climate.
Planted roofs contribute positively to the improvement of the thermal performance of a building. They block solar radiation, and reduce daily temperature variations and thermal ranges between winter and summer. In this paper, a calculation has been done, using a stationary method, in order to determine the thermal behaviour of the planted roof and the way it influences the thermal protection of the building, in accordance with Greek climatic conditions. Planted roof elements with different heights of plants and different drainage layers are calculated and a comparison between a bare roof and a planted roof is made. All sections are calculated with and without thermal insulation. The results are illustrated in figures, in which the temperature of the layers of the planted roof is presented for both winter and summer. The planted roof contributes to the thermal protection of a building, but does not replace the thermal insulation layer.
This paper addresses the general concept of sustainability and relates it to the building owner`s selection of a low-slope roof. It offers a list of performance features of sustainable roofs. Experiences and data relevant to these features for four unique roofs are then presented which include: self-drying systems, low total equivalent warming foam insulation, roof coatings and green roofs. The paper concludes with a list of sustainable roofing features worth considering for a low-slope roof investment. Building owners and community developers are showing more interest in investing in sustainability. The potential exists to design, construct, and maintain roofs that last twice as long and reduce the building space heating and cooling energy loads resulting from the roof by 50% (based on the current predominant design of a 10-year life and a single layer of 1 to 2 in. (2.5 to 5.1 cm) of insulation). The opportunity to provide better low-slope roofs and sell more roof maintenance service is escalating. The general trend of outsourcing services could lead to roofing companies` owning the roofs they install while the traditional building owner owns the rest of the building. Such a situation would have a very desirable potential to internalize the costs of poor roof maintenance practices and high roof waste disposal costs, and to offer a profit for installing roofs that are more sustainable. 14 refs., 12 figs.
Four basic urban structural neighborhoods were exposed to typical summer/winter weather scenarios spanning latitudes 10N, 34N, and 50N. These scenarios included different human comfort levels for interior building temperatures. A numerical urban model (URBAN 3) was used to describe and analyze the systems' energy budgets and the resultant surface temperatures of streets, walls, and roof tops. The examined surface temperature histories are believed to be representative of the more complex urban environments observed in real cities.Vier strukturell charakteristische Stadtgebiete waren typischen Sommer- und Winter-Witterungsformen in Breiten von 10N, 34N und 50N ausgesetzt. Diese Witterungsformen umfaten verschiedene Behaglichkeitsstufen fr Innentemperaturen von Gebuden. Ein numerisches Stadtmodell (URBAN 3) wurde zur Beschreibung und Analyse des Energiehaushaltes der Systeme und der daraus resultierenden Oberflchentemperaturen von Straen, Wnden und Flachdchern verwendet. Es wird angenommen, da die behandelten Entwicklungen der Oberflchentemperaturen fr komplexere Teilgebiete in wirklichen Stdten reprsentativ sind.
Two deterministic models were combined: one for canopy leaf energy budgets and one for street canyon energy budgets. The effects of street parks and roof gardens in contrast to non-vegetated city blocks were examined by the use of four typical urban morphologies, which were exposed latitudinally to summer and winter simulations. A variety of increases and decreases in shortwave radiation, net radiation, sensible heat flux, and system reradiation resulted. These changes appear to represent the generalized limits of the possible responses to the addition of vegetation to non-vegetated city blocks.
This paper presents a mathematical model yielding a sensible, albeit simplified representation of the dynamic thermal behaviour of actual green roofs. Several parametric sensitivity analyses have been carried out to assess the cooling potential of green roofs in summer. The main conclusion of these analyses is that green roofs do not act as cooling devices but as insulation ones, reducing the heat flux through the roof. A relatively small set of parameters have been identified as relevant for green roof design: the leaf area index (LAI) and the foliage geometrical characteristics, the soil apparent density, its thickness, and its moisture content.
Greenery on the Roof: a Futuristic, Ecological Building Method For a More Human Architecture in Harmony with Nature
- R Stifter
- F Hundertwasser
Stifter, R.; "Greenery on the Roof: a Futuristic, Ecological Building Method", Hundertwasser,
F., For a More Human Architecture in Harmony with Nature, Hundertwasser Architecture,
Benedikt Taschen Berlag, GmbH, Cologne, p156-158, 1997.
Haeuser mit Gruenem Pelz
- G Minke
- G Witter
Minke, G. und Witter, G., Haeuser mit Gruenem Pelz, Ein Handbuch zur Hausbegruenung,
Verlag Dieter Fricke GmbH, Frankfurt, 1982.