Roof Surface Research Articles

Aerodynamic Drag Reduction of Commercial Ground Vehicles Using Numerical Techniques

Automobiles of today warrants improved aerodynamic behaviour that results in low drag producing vehicles. Such optimally designed vehicles offer advantages such as better overall performance, desirable driveability, rapid response, improved stability and added fuel economy. In this paper, an attempt is made to accomplish lower drag coefficient by incorporating the dimples shape on the vehicle roof surface. Aerodynamic flow analysis was conducted with and without dimple shape effect on a bus truck trailer and commercial vehicles, using ANSYS Fluent software tool. Effect of different sized and shaped dimples on aerodynamic performance was analysed as well. Results obtained were validated with available literature and it is found that coefficient of drag obtained showed less than 10 % error. It was found that drag values were significantly reduced with dimple effect on both the commercial vehicles. Both models demonstrated that the fluid flowing on the surface did not separate from the vehicle roof, and the vortex size at the back was reduced. Further paper gives a detailed study of various parameters like turbulence model effect, pressure distribution on the vehicles, temperature and mach number variations. This study is proposed to enhance energy efficiency of the automobiles as better aerodynamics improves their mileage and fuel economy.

Сontinuous walking beam furnace without water cooling for reheating copper alloy blanks

It takes a special technique to heat up round blanks cast of copper alloys in conformance with applicable process specification, which implies maintaining a low oxidizing atmosphere in a gas furnace. This paper describes a continuous furnace with walking beams that are not watercooled designed to heat up round blanks to the maximum temperature of 1,000 ºC. The furnace, which stands before the pipe press for making pipes of different sizes, is fueled by natural gas burned in high-speed burners with the air flow rate of α = 0.98 in hot zones and that of α = 1.05–1.1 in preheating zones. The side walls of the furnace are equipped with high-speed burners which serve to intensify the convective heat transfer inside the furnace. The burners ensure a transverse/countercurrent flow of gases with an intense transverse jet circulation. The furnace is equipped with a panel roof lined with ribbed ceramic fiber blocks (original design by UralTermoKompleks) which serves to intensify the radiation heat transfer without raising the temperature. A larger interior surface of the furnace roof leads to an increased radiation heat flow density and hence higher heating rates. It means that the furnace has better performance at the same temperature. The furnace is equipped with charging and discharging systems. An eccentric is responsible for moving the walking beams. An integrated control system controls heat in each of the five zones of the furnace guided by thermocouples and charging and discharging modes. The furnace has been fully commissioned.

Facile fabrication of cool yellow pigment with enhanced NIR reflectance by tailoring oxygen defects and its application in energy-saving building

Intensity of absorption tail at long wavelength side of absorption edge is affected by concentration of oxygen vacancy (Ov), which determines chromaticity, near-infrared (NIR) reflectance and application value of cool pigments. In this work, a feasible strategy is proposed to restrain the generation of Ov by lattice distortion to enhance color and NIR reflectance. Compression lattice is formed by introducing smaller ions of Ti4+ or Zr4+ into Tb site in SrTbO3 host. This results in significant reduction of concentration of Ov. Compared to SrTbO3, color component L* of SrTb0.6Zr0.4O3 increases from 69.09 to 87.30. Moreover, NIR and solar reflectance are remarkably enhanced, reaching 18.3% and 19.3%, respectively. In addition, 11.6 °C and 5.6 °C decreases in temperature were observed for inner surface of roof and indoor room of simulation house. The strategy proposed in this work will contribute to developing color-cool pigments with suitable properties and high solar regulation ability.

A Geometric-Feature-Based Method for Automatic Extraction of Anchor Rod Points from Dense Point Cloud

As the technology of high-precision 3D laser scanning becomes increasingly prevalent in the fields of hydraulic building modeling and deformation monitoring, the quality of point clouds plays an increasingly crucial role in data processing. This paper investigates an automatic extraction method of anchor rod points based on geometric features, which focuses on the influence of anchor rod points and mixed pixels in the data of an underground powerhouse of a pumped storage power station on modeling and deformation monitoring during the construction period. This workflow consists of two steps that can automatically extract anchor rod points from high-density point cloud data. Triangular mesh features in the local neighborhood and the parameters of the anchor rods are used to locate the anchor rod in downsampled data, and curvature features are used to extract anchor rod points precisely. The experiment of extracting anchor rods shows that the accuracy of this method of initial identification is 97.2%. Furthermore, precise extraction based on curvature curve fitting is applicable. This method can accurately separate the three types of anchor rods from the dense point cloud on the rough surface of a cavern roof; the false-extraction rate of anchor rod points is about 0.11% to 5.09%. This method can provide high-quality and dependable data sources for the precise registration, modeling and deformation analysis of point clouds in a construction cavern.

Large-eddy simulation of wind loads on a roof-mounted cube: application for interpolation of experimental aerodynamic data

Failure of roof-mounted equipment in extreme wind events such as hurricanes is a significant contributor to wind-related property loss. Proper understanding of the nature and magnitude of wind-induced loads on these structures is essential to ensure their safety during severe storm conditions. Previous studies showed that wind loads on roof-mounted equipment vary significantly depending on the shape, size, location, and elevation relative to the roof surface. In this study, using large-eddy simulation (LES), wind loads on cube-shaped equipment mounted on the roof of a low-rise building are investigated to study the effect of equipment elevation on the wind loads aiming to complement existing experimental aerodynamic data. The accuracy and reliability of the LES results are assessed stage by stage. First, the characteristics of the incident wind profiles reported in the experimental study are reproduced in LES. Then, surface pressure distribution and force coefficients found from the LES are validated against the experimental aerodynamic data for selected representative cases. Finally, the variations of peak drag and uplift force coefficients with different equipment elevations are investigated in detail with the help of the flow field acquired from the LES near the rooftop equipment. The results from the current work show that the peak uplift force coefficients are significantly reduced for elevated equipment. However, considering all the cases studied, the peak drag force coefficients remain relatively unchanged with equipment elevation.

Study on Initial Fracture Characteristics of the Main Roof in Fully Mechanized Caving Mining of Inclined Coalbed

In view of the occurrence conditions of inclined coalbed, the deformation and failure characteristics of the main roof will affect the safe production of the working face. Therefore, the study of the deformation and failure characteristics of the main roof in the inclined coalbed has guiding significance for the control of surrounding rock. This paper takes the II1042 working face of Taoyuan Coal Mine as the research background, adopts the methods of theoretical analysis, numerical calculation, and field practice to analyze the evolutionary characteristics of the initial failure of the main roof of the working face under the background of the inclined coalbed, and explores the mechanical behavior characteristics of the working face roof during the mining of inclined coalbed. Based on the elastic thin plate theory, a mechanical model of the overlying rock roof of a large-angle coal seam is established, and the mechanical characteristics of the surrounding rock under the initial failure of the main roof under the unbalanced load are studied. The stress distribution characteristics of the lower surface are summarized, and the evolution law of the initial fracture of the main roof is summarized. According to the actual geological conditions of the II1042 working face of Taoyuan Coal Mine, the failure characteristics of the main roof and the initial breaking step distance are obtained by analysis, and the analysis results are verified by monitoring the mine pressure of each part of the target working face on site. The research results show that: ① Under the unbalanced load of the inclined coalbed, the deflection surface of the main roof of the coal seam is asymmetrical with respect to the arrangement direction of the working face, and the maximum deflection point is located at the upper middle position of the working face, namely (a/2, 1.836 b/π), and the main roof of the working face breaks for the first time when it advances to 35 m. ② With the advancement of the working face, the two long sides of the roof break first. With the deflection and deformation of the roof, the tensile stress in the middle of the main roof reaches the tensile strength of the rock and breaks, and then the two short sides of the roof break under the action of the breaking and turning of the rock, and the upper short side will break before the lower one. ③ According to the monitoring and analysis of the rock pressure at each part of the working face, it is judged that the initial pressure step distance is between 28.2 m and 34.6 m, which is consistent with the theoretical analysis results.

Experimental comparison of two extensive green roof designs in Northwest Mexico

Accelerated population growth and urbanization have negative environmental impacts, such as habitat destruction, biodiversity loss, natural resource depletion, and pollution. They speed up climate change, contribute to urban heat islands, and increase energy use. Green roofs (GRs) can reduce the ecological footprint and improve the quality of life within cities but require careful design for best results. This study analyzes the thermal performance of GRs in six experimental modules differing in roof cover: concrete, reflective coating, dry soil, wet soil, traditional GR with Sedum acre, and wetland GR with Salicornia pacifica. The two plant species have different carbon assimilation metabolisms: S. pacifica is a native wetland C3 species with diurnal transpiration that grows in flooded soils, and S. acre is an exotic Crassulacean Acid Metabolism (CAM) species with night-time transpiration, commonly used in GRs. GRs were monitored during the winter of 2020 in Ensenada, Baja California, México, a city with a semi-arid Mediterranean climate. We found that vegetated covers reduced the temperature oscillation with an insulating effect. During the warmest week, they reduced the internal roof surface temperature (Ts,in) up to 12.4 °C in comparison to the concrete roof. They maintained Ts,in up to 5.8 °C warmer than concrete roof during the coldest week, indicating that GRs are efficient thermal regulators in this region, potentially reducing buildings’ thermal load as well as providing additional ecosystemic services. Since S. pacifica had higher survival and coverage, we recommend its use in GRs located in Northwest Mexico and climatically similar world regions.

Biosolar green roofs and ambient air pollution in city centres: Mixed results

Green roofs are known for their ability to reduce ambient air pollution. While the accurate valuation of the air pollution removal services provided by green roofs is rapidly developing, much of this research is still in its infancy, with only a small number of in-situ studies that truly examine the impact of green roofs on city air quality. In this study we present the longest study conducted on an Australian green roof with in-situ air quality monitoring. Field measurements were utilised to calculate the ambient air pollutant removal of an extensive green roof compared to a proximal, near-identical conventional roof over three seasons. The average concentrations of ambient ozone was lower on the green roof compared to that of the conventional roof surface. The theoretical ozone and nitrogen dioxide removal rates on the green roof were higher than the average concentrations calculated from previous research at 3.82 g m-2y-1 and 1.29 g m-2y-1 respectively. There was no significant difference in the average suspended particulate matter concentrations between the two roofs. The particulate matter removal rate was lower than the average previous findings at 0.29 g m-2y-1. The green roof studied was theoretically capable of removing 0.5 kg of PM2.5, 6.9 kg of O3 and 2.3 kg of NO2 per year, values which were significantly higher than the conventional roof. Ambient nitrogen dioxide concentrations were higher on the green roof – largely attributed to local construction activities.

Energy Conservation of Residential Buildings in Extreme Climates with Phase Change Material-Aluminum Radiation Reflector Cool Roof

ABSTRACT In arid locations, global warming raises the indoor air temperature and energy utilization of residential and commercial buildings. Developing effective passive cooling solutions is critical for lowering room air temperatures and improving building energy consumption. The phase change materials (PCMs) based thermal energy storage (TES) roofing systems have received more attention in recent years due to their ability to decrease the energy consumption of the buildings. The PCMs were used in different ways, such as encapsulated PCM systems, free cooling applications, air-conditioning systems, and sorption cooling systems. The results of various studies have revealed that a decrease in indoor air temperature of approximately 1–3°C was obtained. Integration of PCMs with other cooling techniques may further improve the building cooling effects. The current study attempts to improve the cooling effect by integrating a PCM with a double-skin aluminium radiation reflector (ARR) in the summer seasons of an arid region like the Sultanate of Oman. Field investigations indicated that the double skin PCM-ARR cool roof room had a substantial drop in room air and roof surface temperatures than a standard bare concrete roof. The experimental investigation revealed that the room air, interior, and exterior roof surface temperatures of the double skin PCM-ARR roof model were reduced by 3.63°C (9.08%), 12.68°C (30.1%), and 16.92°C (37.3%) than the reference roof model, respectively. The corresponding average reduction in the heat flux was 18 W/m2. The presence of dynamic air between PCM and ARR resulted in the roof’s superior thermal resistance (convective heat flux). The experimental research has shown that during the summer seasons, the double skin roof PCM-ARR substantially lowers temperatures of interior air and roof surface of buildings.

Sustainable green roofs: a comprehensive review of influential factors.

Green roofs have gained much attention as a modern roofing surface due to their potential to deliver many environmental and social benefits. Studies have indicated that different GR designs deliver different ecosystem services, and there are important factors that affect GR performance. This article reviewed significant factors that influence GR performance and sustainability. Substrate and drainage layer material choice significantly affects stormwater retention potential, leachate quality, plant survival, and determines GR environmental footprints. Subsequently, type of plants, their form, and kinds used on GRs impact GR ecosystem function. Leaf area is the most studied trait due to its influence on the cooling potential and energy performance. In order to achieve a sustainable GR, it is essential to select the type of plants that have a high survival rate. Perennial herbs, particularly forbs and grass as dominant groups, are heat and drought tolerant, which make them suitable in GR experiment. Furthermore, selecting a suitable irrigation system is as important as two other factors for having a sustainable GR. Irrigation is essential for plant survival, and due to the current pressure on valuable water sources, it is important to select a sustainable irrigation system. This review presents three sustainable irrigation methods: (i) employing alternative water sources such as rainwater, greywater, and atmospheric water; (ii) smart irrigation and monitoring; and (iii) using adaptive materials and additives that improve GR water use. This review sheds new insights on the design of high-performance, sustainable GRs and provides guidance for the legislation of sustainable GR.

The Roof Safety under Large Mining Height Working Face: A Numerical and Theoretical Study

As an important technology of thick coal seam mining, fully mechanized mining with a large mining height has high mining efficiency. In order to study the roof safety control of large mining height working face, the 122106 working face of Caojiatan coal mine is taken as the engineering background. The numerical simulation method is used to analyze the control ability of roof subsidence when the support strength is 1.2 MPa, 1.4 MPa, 1.6 MPa, 1.8 MPa, 2.0 MPa, and 2.2 MPa. The results show that the support strength of hydraulic support is negatively correlated with roof subsidence. Through theoretical analysis of the mechanical model of the support and surrounding rock under the filling condition, it is shown that the height of the gap between the filling body and roof is the main influencing factor of roof subsidence: the smaller the height of the gap between the filling body and roof, the better the control effect on the roof. Through numerical simulation, the roof subsidence and surface subsidence under different filling rates are analyzed. The results show that when the filling rate increases to 80% the control of roof subsidence achieves better results. Taking production safety and economic benefits into consideration, when the reasonable support strength of the working face is determined to be 2.0 MPa and the filling rate is 80%, the safety control of the working face roof can be ensured.

Assessing the Potential of Rooftop Photovoltaics by Processing High-Resolution Irradiation Data, as Applied to Giessen, Germany

In recent years, prices for photovoltaics have fallen steadily and the demand for sustainable energy has increased. Consequentially, the assessment of roof surfaces in terms of their suitability for PV (Photovoltaic) installations has continuously gained in importance. Several types of assessment approaches have been established, ranging from sampling to complete census or aerial image analysis methodologies. Assessments of rooftop photovoltaic potential are multi-stage processes. The sub-task of examining the photovoltaic potential of individual rooftops is crucial for exact case study results. However, this step is often time-consuming and requires lots of computational effort especially when some form of intelligent classification algorithm needs to be trained. This often leads to the use of sampled rooftop utilization factors when investigating large-scale areas of interest, as data-driven approaches usually are not well-scalable. In this paper, a novel neighbourhood-based filtering approach is introduced that can analyse large amounts of irradiation data in a vectorised manner. It is tested in an application to the city of Giessen, Germany, and its surrounding area. The results show that it outperforms state-of-the-art image filtering techniques. The algorithm is able to process high-resolution data covering 1 km2 within roughly 2.5 s. It successfully classifies rooftop segments which are feasible for PV installations while omitting small, obstructed or insufficiently exposed segments. Apart from minor shortcomings, the approach presented in this work is capable of generating per-rooftop PV potential assessments at low computational cost and is well scalable to large scale areas.

Optimized radiative parameters of building roof surfaces for energy efficiency: Case studies in China

To improve the thermal performance of the roof and building energy efficiency, this study investigates the optimized combination of the shortwave absorptivity and longwave emissivity for exterior roof surfaces. A simplified 3-day field measurement was first performed for model validation. Next, simulations were performed in 12 representative Chinese cities with both radiative parameters varying between 0.1 and 0.9 for the exterior surface of un-insulated and insulated roofs, focusing on the thermal load of the building. Experiment confirmed that WUFI Plus could reliably process the radiative boundary condition, with the daily surface temperature difference between the measurement and simulation being approximately 1 °C. Furthermore, simulation showed distinct requirements for the radiative parameters of the building roof surface, with regional and seasonal differences being significant. In general, for cold areas and seasons, a combination of high shortwave absorptivity and low longwave emissivity is preferred. Conversely, for hot conditions, a low shortwave absorptivity combined with a high longwave emissivity is optimal. For scenarios with balanced heating and cooling loads, optimization can only be achieved through case-by-case analysis. Finally, a map of optimized radiative parameter combinations for building roofs is provided, accounting for annual building energy efficiency.

Study of the Evolution of Water-Conducting Fracture Zones in Overlying Rock of a Fully Mechanized Caving Face in Gently Inclined Extra-Thick Coal Seams

To study the caving of thick hard overburdens and evolution of water-conducting fracture zones in fully mechanized top-coal caving faces of gently inclined extra-thick coal seams, we comprehensively analyzed the 8103 working face of the Beixinyao Coal Mine. We investigated to the caving characteristics of thick hard overburden in fully mechanized top-coal caving faces, fracture information of the internal structure of overburden, and development heights of the “two zones” of overburden after coal mining. Our research methods included those of similarity simulation experiments, such as the use of microseismic monitoring systems, numerical simulations, theoretical analysis, and engineering practice. The results showed that the overlying strata generally experienced stages of roof caving, crack formation, delamination, crack development, and surface subsidence. Due to the influence of overlying strata movement and mining, the separation layer experienced an evolution process called “emergence-development-closure”, where the height of the overlying strata caving envelope increases with the advancing of the working face. When full mining was achieved, the overlying strata caving height was stable, and the height development range of the water-conducting fracture zone was 100–120 m, which is consistent with the height of the overlying strata caving envelope. Most microseismic events occurred near the water-conducting fracture zone, and the water-conducting fracture zone was formed in an area with concentrated energy density. In our numerical simulation, the concentrated distribution area of the fracture field was characterized by a “bridge arch”. The fracture development model in the middle of the goaf was higher than at both ends of the working face, and roof strata deformation was obvious. When the energy value of microseismic event reaches 108.708 J, cracks are produced, and these cracks gradually penetrate to form water-conducting fracture zones. Engineering practice showed that the height range of the water-conducting fracture zone was 98–123 m, and caving of the thick hard overburden and evolution of the water-conducting fracture zone in a fully mechanized top-coal caving face provide a scientific basis for water prevention and control.

Experimentally optimized particle–polymer matrix structure for efficient daytime radiative cooling

The polymer–particle matrix structure has attracted great interest for daytime radiative cooling due to its various advantages; however, cost-effective fabrication process development and proper material selection are crucial tasks. Herein, we illustrate the selection of fabrication process and materials based on development, characterization, and experimental performance. The initial selection is based on solar radiation backscattering and isotropic thermal emission properties of polymers and particles. Among potential polymers (PMMA, PVDF, and PU), PMMA is experimentally found more suitable for radiative cooling because of negligible absorption in the solar radiation spectrum. Among the selected particles (CaCO3, BaSO4, ZnO, and SiO2), the experimental performance of BaSO4 in the polymer matrix is found to be excellent. Furthermore, the optimum particle volumetric concentration is found at 70%, with an optimum thickness of 500 μm for the substrate independent radiative cooler. Spray-coating is found to be a better option for fabrication as compared to drop casting. The performance evaluation was carried out at Varanasi, India for over two months to investigate the environmental parameters' effect on performance. For an optimized structure, the observed maximum temperature drop from the ambient is 6 °C (17 °C lower than bare roof surface) during noontime and 9 °C during the evening. At ambient temperature, the recorded cooling power is 35 W/m2 at noon (solar peak) and 78 W/m2 in the evening for the experimentally optimized structure.

The energy-efficient design of sustainable green roofs in Mediterranean climate: An experimental study

Green roofs were proposed to broaden nature-based solutions within the perspective of the ecological transition for the built environment. In this paper, an innovative and sustainable green roof was designed to optimize the energy performance in Mediterranean area during summer season by means of local-available and recycled materials, thus reducing the environmental impacts. This new green roof technology consisted of recycled polyethylene granules from the regeneration of disused agricultural plastic films as drainage layer and a substrate made of local-sourced materials with high percentage of organic matter and it was compared to two traditional green roofs and to the existing roof. The energy-efficient design was based on the thermo-physical parameters of the green roof (surface temperatures, heat flows and volumetric water content) and of the building (surface temperature of the ceiling) and on the thermal dynamic parameters (decrement factor, time lag and cooling potential). In addition, these thermo-physical parameters were correlated to the Mediterranean climate during summer season. The result demonstrated that although the proposed green roof reached higher surface temperatures than commercial solutions, it maintained an almost constant volumetric water content, it reduced daily fluctuations between minimum and maximum temperatures, it resulted in lower thermal flow through the cross-section, it reduced the surface temperatures inside the building by about 2 °C compared to the traditional roof, thus decreasing the energy consumption for building cooling and greenhouse gas emissions, and it had better dynamic thermal performance than commercial green roofs. Once the energy-efficient design of the proposed green roof technology was proved, the sustainability and the life cycle performance of the recycled polyethylene was discussed, also considering the costs.

Influences of zinc loads in urban catchment runoff: Roof type, land use type, climate and management strategies

The contribution of ecotoxic dissolved metals from metallic roofs into urban waterways is a global issue. Identifying the specific origin of dissolved metals is critical to enabling appropriate stormwater management approaches that can provide the intended outcome of cleaner urban waterways. An event load pollutant model, Modelled Estimates of Discharges for Urban Stormwater Assessments (MEDUSA2.0), was used to predict the zinc load contributed from individual roof surfaces, under a wide range of rainfall conditions. Zinc was chosen as the pollutant of most concern given the extensive area of zinc-based roof surfaces, and the prevalence and mobility of zinc within urban waterways. The model categorized each roof by surface material and condition, and was run for individual rain events across multiple years to illustrate the influences on zinc loads from both surface type and rainfall conditions. Scenarios of future management were also assessed through the model to compare their benefits in terms of load reductions against the current baseline loadings. To understand how the load prediction and scenario modelling can provide valuable guidance for stormwater management decision-makers, the model was applied to a large urban catchment in Christchurch, New Zealand. Seven representative subcatchments of the varying proportions of industrial, commercial and residential land use type were also modelled to compare zinc loads generated. Results showed that an individual catchment's composition of roof types was the main driver of zinc load generation rather than the catchment's land use type. The modelled management scenarios demonstrated that reductions of 30% zinc could be achieved by changing only 4–13% of a subcatchment's unpainted zinc-based roof surfaces.

A numerical study of cool and green roof strategies on indoor energy saving and outdoor cooling impact at pedestrian level in a hot arid climate

Green and cool roofs retrofit technologies, aim to mitigate the urban heat island effect and cooling energy demands from buildings. This study reports on parametric energy modelling of energy saving loads and indoor air temperature, as well as microclimate modelling of outdoor air temperature. The work adds new knowledge by evaluating roof retrofit technologies at the building and neighbourhood scale, and the results should guide strategic decisions for building envelope retrofitting. The simulations respectively predicted a 10% and 7.5% reduction in the cooling load for cool and green roofs versus a conventional roof. In summer, the indoor air temperature was similar for these roofs, but in winter the cool roof's indoor air temperature was 0.5°C lower than the green. In the microclimate simulation, average roof surface temperatures were 31.5°C (cool) and 31.3°C (green), versus 40.2°C (conventional); the air temperature difference was −0.8°C (cool) and −0.6°C (green) against the conventional roof.

Investigation of Cool Roof Based on Reflective Paints, Evaporative Cooling, and Shading

Abstract In this study, three different approaches are investigated for keeping the roof cool and reducing the heat flow inside a building located in Kanpur, India. In the first approach, various reflective paints are investigated and their performance degradation over a year is examined along with the cost-benefit analysis. In the second approach, the roof surface is kept wet, and due to water evaporation, the roof was kept cool. In the third approach, the effect of shading on the rooftop surface temperature is studied. It is observed that without any cooling, the rooftop temperature can rise about 20 °C above the ambient air temperature. The application of white acrylic paints can reduce this temperature rise to about 5–7 °C. However, after a year due to degradation, this temperature rise is about 10–12 °C. Using evaporative cooling the rooftop temperature can be lowered even below the ambient air temperature by about 3 °C. However, this approach will require active management of the system and consumption of water. The cost for the first two approaches is estimated to be about 5–6 Rs./sq.ft with a payback time of 2 years. Shading can reduce the temperature rise to about 5 °C. Structures meant for other purposes such as photovoltaic panels can serve the additional benefit of cooling the roof. Shading seems to be a robust and low-maintenance option, and cost analysis of structures meant primarily for shading the roof needs to be explored.

Wind Turbines and Rooftop Photovoltaic Technical Potential Assessment: Application to Sicilian Minor Islands

In order to achieve climate goals and limit the global temperature rise, an increasing share of renewable-energy sources (RESs) is required. However, technologies for the use of RESs need to be integrated into the landscape and ecological heritage to ensure a fully sustainable energy transition. This work aims to develop a scalable technique for integrating the estimation of rooftop PV and wind potential into spatial planning, providing a framework to support decision-makers in developing energy policies. The methodology is applied to the minor Sicilian islands, which are characterised by significant environmental and landscape constraints. The methodology is used to identify the areas eligible for the installation of onshore wind turbines and the usable roof surfaces for the installation of PV systems. It is shown that the available technical potential of rooftop PV installations could ensure a higher production than the actual consumption on 13 of the 14 islands studied. Nevertheless, efforts must be made to improve the legal framework, which currently places major limits on the use of wind energy.