Roof Profile Research Articles

ВПЛИВ СУЧАСНИХ ТЕНДЕНЦІЇ ВИКОРИСТАННЯ СОНЯЧНОЇ ЕНЕРГЕТИКИ НА ЕСТЕТИЧНІ ЯКОСТІ МІСТА

Energy independence remains a priority task for most European countries. Along with traditional energy sources, more and more attention is being paid to renewable energy usage. The best solution for city residents is the use of solar energy for the local needs of individual households. However, chaotic installation of solar panels on the roofs has a negative impact on the aesthetic qualities of urban environment. Many problems as well arise during installation of panels itself on the roof structure. After all, solar panels have significant weight, which usually was not taken into account when calculating the roof structure. The wind load, which is higher for planar elements, also was not taken into account, which can provoke negative consequences like destruction of an entire structure during exploitation. Key problem is that in most cases panels are being installed on the already existing roof and were not laid in the project. Conducted research has revealed the negative impact of voluntarily installed solar panels on aesthetic qualities of the city. Argued the importance of coordinating the installation of solar energy accumulating elements with the architecture of the building and the environment by selecting an appropriate shape, texture and color. Proved the need to foresee during the design process the use of solar panels in the construction of the roof and walls to partially supply buildings with energy at the local level. Envisaging solar panels at the design stage will avoid duplicating the roof profile, which will reduce the weight of the roof structure and extend its service life. The analysis of main methods for organizing the "solar roof" showed that the most appropriate, from an aesthetic point of view, is the use of solar roof tiles. Based on analysis of available materials for accumulating solar energy, it was found that today there is no manufacturer that provides a complete solar roof with all its elements (gutters, snow retainers, deaerators, ladders, etc.). However, it is possible to choose elements with the corresponding texture and color and combine roof elements from different manufacturers.

Building Height Extraction Based on Satellite GF-7 High-Resolution Stereo Image

Abstract. High-resolution remote sensing images can distinguish objects of smaller size, so as to more clearly express the texture features and structural information of objects, and provide a data source for the development of large-scale mapping, high-precision stereo measurement and other fields. The purpose of this paper is to complete the height estimation of the buildings by analyzing the stereoscopic observation formed by the front and rear view images of the Gaofen-7 line array CCD. After determining the roof profile of the building on the rear-view image, assuming a series of object elevations of the building, that is, searching for elevations with a certain step distance within a certain elevation search range, adopt the object-based image matching VLL algorithm, Through the RFM imaging model of the Gaofen-7 sensor, the rear-view contour is projected to the front-view image, and then the PSNR is selected as the similarity measure of the window, and the similarity of the image block area corresponding to the front- and rear-view contour is calculated. Corresponds to the hypothetical object elevation as the estimated height of the building. Under the technical route of this paper, the height of buildings on high-resolution images can be estimated to a level within 3 meters of accuracy.

Analysis of upper and lower nappe profiles of large orifice for the design of bottom and roof profiles of high head orifice spillway

Abstract Large orifices are constructed for dams to release water and sediments from reservoirs. Such structures are called submerged spillways. Numerous studies have investigated discharge coefficient, velocity coefficient, and head loss coefficient of large orifices; however, the literature lacks data on the upper and lower nappes of the jets from these orifices. In the present experimental study, the upper and lower nappes are investigated up to 80 m head at different gate openings. The observed minor deviation between the lower nappe profile and trajectory profile equation suggests sensitivity to different factors. The significant role of the coefficient of velocity, averaging at 0.926, highlights its impact on minor deviation. Subsequently, the impact of the solid bottom profile on the discharge coefficient and upper nappe profile are also examined. The results show improvement in discharge coefficient of a sharp-edged large orifice, which increased from 0.69 to 0.74. The results also indicate that the upper nappe profiles and United States Bureau of Reclamation (USBR) profiles are similar. The improvement in the upper nappe profile indicates the significant role of the solid bottom profile, which consequently was found to be helpful in defining the roof profile of an orifice spillway. .

An integrated technical, economic, and environmental framework for evaluating the rooftop photovoltaic potential of old residential buildings

Energy-saving reconstruction of old residential buildings is a vital way to achieve sustainable development, but the potential of rooftop photovoltaic (PV) energy-saving in old residential buildings has not been studied. This study established a basic framework for the estimation of rooftop PV technical, economic and environmental potential in the old residential buildings of Nanjing City, and provide the prediction results for the development of rooftop PV development plan in Nanjing. We estimated the available area, maximum electricity generation, environmental and economic benefits of rooftop PV in five districts of Nanjing by using building roof profile data, calculation method of maximum solar radiation at optimal tilt angle and GIS method. We find that the electricity generation potential of installing rooftop PV in the old residential buildings in the study area would meet about 17.7–20% of the residential electricity demand under three scenarios of the PV performance ratios (PR). Additionally, the carbon reduction potential of the life cycle rooftop PV reaches 13912874.12t (PR = 0.85), 13094469.76t (PR = 0.8), and 12276065.4t (PR = 0.75), respectively; and the result of economic potential shows that the life cycle of rooftop PV cannot generate economic benefits with an NPV value less than 0. The feasibility analysis framework provided in this paper can be applied to the assessment of rooftop PV potential in other cities in China, and provide valuable advice for the rational planning of rooftop PV.

Insights into green roof modeling using SWMM LID controls for detention-based designs

Rainfall–runoff responses were observed in a laboratory environment using a rainfall simulator and a 7.43 m2 green roof cassette equipped with weighing lysimeters. SWMM LID controls were developed for various green roof profile configurations based on the physical properties of the composite materials. Unknown parameters affecting the drainage layer were adjusted in calibration. The cassette was modeled both as a typical Green Roof LID control using Manning’s equation at the drainage layer and a Bioretention LID control using an orifice equation in the drainage layer. Key parameters from a sensitivity analysis that were not directly measured were Manning’s roughness of the drainage layer, the drainage coefficient at the orifice, and the conductivity slope (HCO). The hydraulics of roof drains were considered by varying the width of the drain outlet from 0.25 m–1.22 m. During calibration and validation of multiple events, SWMM modeling resulted in a good fit compared to observed results (Nash–Sutcliffe model efficiency coefficient values of 0.70–0.89). Key limitations of SWMM green roof modeling are discussed with suggested improvements for future consideration.

Design Using Special Steel Sheet Profiles – Procedures Developed within the Framework of Grispe and Grispe Plus Projects

AbstractNew computational procedures developed within the framework of international research projects „Grispe” and „Grispe Plus” are briefly presented and characterised here. Considered algorithms pertain to the verification of bearing capacity and serviceability of selected bearing structure components erected with especially shaped thin-walled sheet metal panels. Structural components of this type are so far rather absent from the codes, and as a result the unequivocal design requirements have not been developed for them. Key problems related to the detailed analysis of the following element classes: steel decks with embossments, indentations and/or outwards stiffeners; liner trays; corrugated sheeting; curved profiles; cladding and roof profile assemblies; perforated and holed profiles; external interlocking planks and their assemblies are indicated in the text. The procedures formulated as a part of the projects indicated above have been delivered to CEN as an official proposal of amendments and/or additions submitted for introduction to the new generation of Eurocodes currently under preparation, and especially as an extension to the code EN 1993-1-3.

Investigation into the Aerodynamic Performance of a Concept Sports Car

Transport aerodynamic optimisation has become an increasingly important field of study in response to emerging factors, such as new human needs and market demands. This paper provides a concept in-house built sports-car aerodynamic and shape optimisation. Wind tunnel tests and numerical simulations have been set-up and conducted to understand the concept vehicle aerodynamic structure and needs for performance improvement. A computer-aided design model has been developed and implemented into the computational fluid dynamics (CFD) software of StarCCM+ for detailed analysis. A 1/4th full-scale fibreglass model has been manufactured for validation. The combined experimental and CFD analyses show that the original aesthetic design exhibits high rear-end lift-force. Modifications have been assessed to improve the drag and lift forces for the front, middle and rear regions. Several geometrical changes are introduced, including new rear-wing design. Also, the front end, roof profile and various ducting modifications have been considered. The introduced design changes lead to optimised downforce of -560.18 N with negligible increase to the accumulated drag effects with C_D≤0.3.

Prediction of roof supporting pressure for shallow tunnels in layered soils incorporating the effect of pore water pressure

In this study, we propose a method for predicting the supporting pressure required for shallow tunnels in layered soils, based on a curved roof collapse mechanism with multi-failure surfaces. In this method, the effect of the number and thickness of soil layers, pore water pressure, arbitrary roof profile, and ground additional load is considered simultaneously. A nonlinear power-law failure criterion is employed to describe the failure characteristics of the roof soils. The internal energy dissipation rate and the work rates produced by external forces are obtained based on the associated flow rule and plasticity potential theory. The analytical expressions of the required supporting pressure and roof collapse surfaces are obtained with the upper bound method. Furtherly, a shallow rectangular tunnel in two soil layers is selected for parametric investigation. The change laws of the required supporting pressure and collapse curves under varying parameters are obtained. Furthermore, the corresponding engineering recommendations are given, which may potentially provide references for the support design and construction of shallow tunnels in layered strata.

Increasing efficiency of atriums in hot, arid zones

This research evaluated the efficiency of Atrium in hot, arid regions and investigated the parameters influencing the total energy consumption of an existing shopping mall in Dubai, UAE using the IES-VE energy modeling software. The parameters tested included: Roof profile, Roof ventilation, Number of floors, glazing's Light to Solar Gain ratio (LSG) and the Thermal insulation of the building envelope. The impact of using light sensors was also studied. The light sensors and the roof's thermal insulation resulted in the highest reduction of the atrium's energy, 8.5% and 7.5%, respectively. Increasing the number of floors reduced the energy consumption by 5% per unit area. The roof profile, external wall's thermal insulation and height of the atrium resulted in similar energy reductions of 3.5% each. The external glazing's LSG reduced the energy consumption by 3.25% while the roof ventilation resulted in a reduction of 1.3%. The internal glazing's LSG did not affect the atrium's total energy consumption. An optimal combination of the parameters studies resulted in an energy reduction of about 20%. Thus, this paper presents the optimal design configuration to reduce the energy consumption of an atrium located in a hot and arid climate.

Changes in Temperature and Moisture Content of an Extensive-Type Green Roof

Green roofs ought to be perceived as ensuring a wide-ranging contribution to the sustainable urban environment. The aim of the study was; (1) to investigate and analyse the differences in the surface temperature between four models of green roofs of the extensive type and a conventional roof (covered with bitumen) under the conditions of a continental climate; (2) to assess the influence of environmental parameters (climatic water balance, air temperature, relative humidity, moisture content in the profile) on changes in the temperature of the extensive type green roof profile (substrate and vegetation mat). The study (1) was carried out during the period of June–December 2016 using a thermal imaging camera. As a result, the greatest differences in temperature were noted in June and July, with a maximum difference between the temporary surface temperature of a green roof and a conventional roof of up to 24 °C. The (2) study was conducted on a green roof profile with sedum plant vegetation. The measured parameters were: the temperature of the surface, the temperature and humidity at depths of 3 cm and 15 cm, and active radiation in the photosynthesis process (PAR). As the result, the range of daily changes in the surface temperatures and the vegetation mat were higher than the range of changes in the air temperature. Atmospheric precipitation decreased the thermal gradient in the soil, as well as the temperature fluctuations in the course of a day as a result of the increase in humidity following a rainfall. During the summer period, over the course of a day, the surface temperature was 5 °C higher than the air temperature. The largest correlation was obtained between the air temperature and the temperature of the surface as well as the temperature of the structural layers.

Experimental study of the thermal performance of an extensive green roof on sunny summer days

Green roofs have shown a remarkable effect on the reduction of the building cooling load in summer. The assessment of the thermal performance of green roofs is essential for their design and evaluation. 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.

Design and FE Modeling of UPVC Corrugated Hollow Roofing Sheet

The corrugated roofing sheet of UPVC polymer material is the potential material to replace common roof materials that has been developed in Indonesia. This study describes the design of the roof profile and analysis of the roof structure to static load. The resulting roof profile is a hollow corrugated roofing sheet with five crests and four valleys. The effective width is 860 mm, 10 mm cavity thick, and 45 mm peak height. The finite element model of the hollow UPVC corrugated sheets roof structure shows that the roof structure is capable of withstanding the static load/ mass of 133 kg equivalent of two applicators and capable of withstanding the wind lift force equivalent to 99 km/ h.

CFD Simulation On The Pressure Distribution For An Isolated Single-Story House With Extension: Grid Sensitivity Analysis

Damage due to wind-related disasters is increasing due to global climate change. Many studies have been conducted to study the wind effect surrounding low-rise building using wind tunnel tests or numerical simulations. The use of numerical simulation is relatively cheap but requires very good command in handling the software, acquiring the correct input parameters and obtaining the optimum grid or mesh. However, before a study can be conducted, a grid sensitivity test must be conducted to get a suitable cell number for the final to ensure an accurate result with lesser computing time. This study demonstrates the numerical procedures for conducting a grid sensitivity analysis using five models with different grid schemes. The pressure coefficients (CP) were observed along the wall and roof profile and compared between the models. The results showed that medium grid scheme can be used and able to produce high accuracy results compared to finer grid scheme as the difference in terms of the CP values was found to be insignificant.

Enhancement of CFD validation exercise along the roof profile of a low-rise building

The aim of this study is to enhance the validation of CFD exercise along the roof profile of a low-rise building. An isolated gabled-roof house having 26.6° roof pitch was simulated to obtain the pressure coefficient around the house. Validation of CFD analysis with experimental data requires many input parameters. This study performed CFD simulation based on the data from a previous study. Where the input parameters were not clearly stated, new input parameters were established from the open literatures. The numerical simulations were performed in FLUENT 14.0 by applying the Computational Fluid Dynamics (CFD) approach based on steady RANS equation together with RNG k-ϵ model. Hence, the result from CFD was analysed by using quantitative test (statistical analysis) and compared with CFD results from the previous study. The statistical analysis results from ANOVA test and error measure showed that the CFD results from the current study produced good agreement and exhibited the closest error compared to the previous study. All the input data used in this study can be extended to other types of CFD simulation involving wind flow over an isolated single storey house.

Hydraulic design considerations for orifice spillways

Orifice spillways have been widely recognized as the most appropriate especially for run-of-the-river projects for handling both flood releases and flushing of sediments. The present paper discusses various important parameters to be considered in the design of an orifice spillway, evolution of orifice spillway, and structural design consideration. A need for physical and numerical model for modeling spillway flows has been identified. Literature review on physical and numerical model studies of orifice spillway has been reported. Central water and power research station has contributed in evolving the design of orifice spillway by conducting hydraulic model studies for more than 25 projects. However, no guidelines have been developed as the data was site-specific for each case. Based on the data, a need for further research is identified and discussed in detail. Roof profile is found to be an important hydraulic parameter as it affects the discharging capacity of the orifice spillway. However, design of roof profile has not been standardized so far. Hence, basic research studies were taken up to develop the design guidelines for roof profile using physical and numerical models. The important findings obtained from the basic research study have also been discussed in the present paper. An equation was developed to design the roof profile, which will be useful for the engineers at the initial stage of design of orifice spillway.

Low-carbon electricity production through the implementation of photovoltaic panels in rooftops in urban environments: A case study for three cities in Peru.

Urban environments in Latin America must begin decarbonizing their activities to avoid increasing greenhouse gases (GHGs) emissions rates due to their reliance on fossil fuel-based energy to support economic growth. In this context, cities in Latin America have high potential to convert sunlight into energy. Hence, the main objective of this study was to determine the potential of electricity self-sufficiency production and mitigation of GHG emissions in three medium-sized cities in Peru through the revalorization of underutilized rooftop areas in urban environments. Each city represented a distinct natural area of Peru: Pacific coast, Andean region and Amazon basin. More specifically, photovoltaic solar systems were the technology selected for implementation in these rooftop areas. Data on incident solar energy, temperature and energy consumption were collected. Thereafter, ArcGis10.3 was used to quantify the total usable area in the cities. A series of correction factors, including tilt, orientation or roof profiles were applied to attain an accurate value of usable area. Finally, Life Cycle Assessment was the methodology chosen to calculate the reduction of environmental impacts as compared to the current context of using electricity from the regional grids. Results showed that the cities assessed have the potential to obtain their entire current electricity demand for residential, commercial and public lighting purposes, augmenting energy security and resilience to intermittent natural disasters, with the support of decentralized storage systems. This approach would also translate into substantial reductions in terms of GHG emissions. Annual reductions in GHG emissions ranged from 112ton CO2eq in the city of Ayacucho to over 523kton CO2eq in Pucallpa, showing that cities in the Amazon basin would be the ones that benefit the most in terms of climate change mitigation.

Segmentation of Airborne Point Cloud Data for Automatic Building Roof Extraction

Roof plane segmentation is a complex task since point cloud data carry no connection information and do not provide any semantic characteristics of the underlying scanned surfaces. Point cloud density, complex roof profiles, and occlusion add another layer of complexity which often encounter in practice. In this article, we present a new technique that provides a better interpolation of roof regions where multiple surfaces intersect creating non-manifold points. As a result, these geometric features are preserved to achieve automated identification and segmentation of the roof planes from unstructured laser data. The proposed technique has been tested using the International Society for Photogrammetry and Remote Sensing benchmark and three Australian datasets, which differ in terrain, point density, building sizes, and vegetation. The qualitative and quantitative results show the robustness of the methodology and indicate that the proposed technique can eliminate vegetation and extract buildings as well as their non-occluding parts from the complex scenes at a high success rate for building detection (between 83.9% and 100% per-object completeness) and roof plane extraction (between 73.9% and 96% per-object completeness). The proposed method works more robustly than some existing methods in the presence of occlusion and low point sampling as indicated by the correctness of above 95% for all the datasets.

Three-dimensional upper bound limit analysis of supported cavity roof with arbitrary profile in Hoek-Brown rock mass

Reliably predicting and estimating roof collapse in underground cavities such as mine goafs and power caverns is a serious concern in mining and geotechnical engineering fields. An analytical expression for a three-dimensional (3D) failure mode of a generic-shaped cavity crown is derived according to the upper bound theorem via limit analysis, where the Hoek-Brown yield criterion represents rock mass strength. The proposed method is validated by comparison against the extant research; the comparison also suggests that the roof profile plays a crucial role in cavity stability. Specific example is given to ellipsoidal cavity and the stability graph with respect to roof profile and cavity span is obtained and discussed. The effects of numerous factors on potential collapse are investigated based on the numerical calculation results. These results may provide workable guidelines for the optimization of roof shapes and support designs in minimizing rock detachment above cavity roofs in practice.

Hydraulic investigation and design of roof profile of an orifice spillway using experimental and numerical models

The roof profile of an orifice spillway plays an important role in deciding its discharging capacity. The necessary requirement is that the profile should not experience excessive negative pressures and should be simple to construct. It is found from the literature that the flow through orifice spillway at the entrance does not follow an elliptical roof profile recommended by United States Bureau of Reclamation. During the regime of flow with high heads, flow separation takes place on the orifice roof profile resulting in reduced discharging capacity. It is also found that there is no specific design method available for design of orifice spillway roof profile with respect to the upstream head as well as other parameters. The main aim of the present study is to develop an equation for design of the roof profile of an orifice spillway. Computational fluid dynamics software FLUENT version 6.3.26 was used for the numerical simulations. The numerical model was verified and validated by comparing the results with the physical model. An equation for the design of roof profile was developed after analyzing the observed discharge through orifice, pressures on spillway bottom profile and upper nappe profile of an orifice spillway. The proposed equation was verified with the data which have not been used in deriving the equation. The proposed equation was also validated in terms of coefficient of discharge and pressure distribution on the bottom and roof profile with the existing data of some other real-life orifice spillways. The results are encouraging indicating that the developed equation can be used to get roof profile of an orifice spillway, which can be used at the design stage of an orifice spillway.

Solar Optimization of Housing Development

This study explored how to increase the on-site energy production of row-houses in a new urban development area located in Trondheim (Norway) from the early design stages. The process consisted in an evolutionary algorithmic for optimizing the shape of the building's roof in order to maximize the use of solar energy. Starting from the roof's profile of the traditional Norwegian house unit, different configurations have been tested. The process allowed changing iteratively the inclination and the size of the roof's surfaces. The selected roofs’ shapes guaranteed to get the maximum solar radiation and the solar mapping analysis allows individualizing the most suitable areas to install solar systems on the roofs’ surfaces of the entire district. The final configuration of the row-houses permitted to increase the solar potential around 30% respect the initial design solution.