Rooftop Of Building Research Articles

Extraction of Buildings in Urban Area for Surface Area Assessment from Satellite Imagery based on Morphological Building Index using SVM Classifier

Rooftops are essential features, extracted from satellite images for their significance in applications such as update of urban geodatabase, risk assessment and rescue map. In this work, a methodology (MBION-SVM) which integrates morphological, spectral, shape and geometrical features with SVM classifier to classify the objects within the satellite image into building rooftops and non-rooftops has been proposed. The probable buildings are detected using Morphological Building Index (MBI). The mislabeled rooftops are eliminated by combining Otsu thresholding and Normalized Difference Vegetation Index (NDVI). Geometrical features computed from identified building rooftops are used to train a support vector machine (SVM), and self-correction is performed for removing any mislabeled rooftops and to provide the data on surface area of the perfect rooftops. Here, we have used Very High Resolution (VHR) images of Worldview-2 and Sentinal-2. We have analyzed the performance of the proposed building extraction approach with classification algorithms such as linear discriminant analysis, logistic regression and SVM. Since the proposed method gives an accuracy around 99%, precision of 89%, a perfect recall of 1 and a F-score of 88%, it can be effectively utilized to extract the buildings from VHR images for any appropriate application.

Numerical Study of the Impact of Urban Terrain on the Loads and Performance of a Small Vertical Axis Wind Turbine

In the present study, the performance of a small vertical axis wind turbine (VAWT) is investigated in realistic urban terrain, in presence of large buildings, hill and forested area. Normally, accelerated wind can be observed on the roof-top of the high-rise buildings. Thereby, different factors such as the orography, vegetation and presence of the buildings at the site etc. influence the inflow conditions strongly and subsequently the performance and loads of wind turbines. Due to the continuously varying inflow direction, inclination and highly turbulent nature of the wind, a detailed analysis of the flow field around the building is required. A two-stages approach is preferred to reduce complexity of the problem. In the first part, the inflow conditions are investigated in the large domain by means of CFD and in the second part, performance and loads of the roof-top mounted small VAWT are investigated.

Research on Green Building Rooftop Plant Power Generation System Based on Bionics Principles

This research is based on the detailed design and study of a plant power generation system for green building roofs based on the combination of bionics and design science. The selection of power generation plants is carried out through experiments and research, and based on which the connection between the plant power generation unit and the internal circuit of the building is studied to generate a complete building roof plant power generation system.

Color-neutral, semitransparent organic photovoltaics for power window applications

Semitransparent organic photovoltaic cells (ST-OPVs) are emerging as a solution for solar energy harvesting on building facades, rooftops, and windows. However, the trade-off between power-conversion efficiency (PCE) and the average photopic transmission (APT) in color-neutral devices limits their utility as attractive, power-generating windows. A color-neutral ST-OPV is demonstrated by using a transparent indium tin oxide (ITO) anode along with a narrow energy gap nonfullerene acceptor near-infrared (NIR) absorbing cell and outcoupling (OC) coatings on the exit surface. The device exhibits PCE = 8.1 ± 0.3% and APT = 43.3 ± 1.2% that combine to achieve a light-utilization efficiency of LUE = 3.5 ± 0.1%. Commission Internationale d'eclairage chromaticity coordinates of (0.38, 0.39), a color-rendering index of 86, and a correlated color temperature of 4,143 K are obtained for simulated AM1.5 illumination transmitted through the cell. Using an ultrathin metal anode in place of ITO, we demonstrate a slightly green-tinted ST-OPV with PCE = 10.8 ± 0.5% and APT = 45.7 ± 2.1% yielding LUE = 5.0 ± 0.3% These results indicate that ST-OPVs can combine both efficiency and color neutrality in a single device.

Characteristics of local wind forces on the edges of signboards installed on the rooftops of buildings

Many signboards are installed on the rooftops of low- and middle-rise buildings in Japan, which are often damaged by strong winds. However, there are no specifications of wind force coefficients for such signboards in the Japanese building codes and standards. In the present study, wind tunnel experiments were conducted to collect data on wind force coefficients under various conditions, including building shapes, as well as signboard shapes and locations. The distributions of the maximum peak wind force coefficients were obtained at various wind angles. Based on the results, the variation of the maximum peak wind force coefficient with wind angle was investigated. It was found that very large wind forces occurred near the edges of the signboard at oblique wind angles ranging from 30° to 60° with respect to the outside surface of the signboard. The present study focuses on such conditions that cause large wind forces on signboards. The results indicate that the building shape significantly affects the maximum peak wind force coefficient.

Experimental investigation of wind characteristics and wind energy potential over rooftops: Effects of building parameters

In this study, the wind flow characteristics and wind energy potential over the flat rooftops of tall buildings were investigated systematically via wind tunnel testing. The effects of building parameters such as the building height ratio (Hr ​= ​3, 5, and 7) and the building width ratio (Wr ​= ​1, 2, and 3) were examined. Due to symmetry, the experiments were conducted up to 90° wind direction in a simulated boundary layer flow in increments of 22.5°. For a given building, a 3 ​× ​3 array of points was set on the roof plan and stretched vertically up to a height of z ​= ​2H, H for building height. The vertical wind profiles over the rooftops showed similar patterns at various locations and wind directions. The maximum wind energy amplification factor Cw,max generally increased with Wr and Hr, but it was far more sensitive to Wr than to Hr. The Cw,max values ranged from 1.6 to 2.7, which suggests the great potential for a large wind energy yield over rooftops. However, hub heights from z/H ​= ​1.02 to 1.19 demonstrated much lower values than those given in the literature. This study provides valuable experimental data for the guidance of roof-mounted wind turbines.

Towards nearly zero-energy residential neighbourhoods in the European Union: A case study

The European Union (EU) aims to establish a guideline that requires all new buildings to comply with nearly zero-energy buildings (NZEB) by 2030. This decision involves new technologies based on concepts that meet international standards. This research aims to review the literature on ‘net zero-energy building’ and analyses the possibility of applying this research on nine statistically representative neighbourhoods of the building stock'in Belgium, depending on the built density. All the areas, grouped into four categories (urban, peri-urban, suburban, and rural neighbourhoods), were used for current energy consumption analysis and to evaluate prospective scenarios based on four major challenges, namely climate change, building renovations, photovoltaic panels, and sustainable mobility. In addition, a new approach combining several scenarios to further improve energy needs at the neighbourhood scale is also highlighted. The nine different types of neighbourhoods studied are commonly found in different countries across the EU. The average reduction in energy consumption of neighbourhoods (buildings + daily mobility) in 2040 (compared to reference year 2012) will likely reach 5.69% attributable to a 20% reduction in distances travelled, 6.48% to climate change, 12.95% to the current annual buildings renovation rate, 18.76%–100% electric cars, 22.26% for doubling the current buildings renovation rate, 31.62% and 63.25% to a light or heavy renovation of the entire building stock, respectively. Moreover, installing 20 m2 of solar panels on the rooftops of each residential building would produce renewable energy equivalent to 6.53% of the current global energy consumption. Finally, the results show that more than 90% of current energy consumption can be reduced at the neighbourhood scale (buildings + daily mobility) by combining a heavy renovation of all the buildings, electric vehicles, and photovoltaic panels. This scenario allows reaching the ‘nearly zero-energy’ target at the neighbourhood scale.

Performance assessment of three grid-connected photovoltaic systems with combined capacity of 6.575 kWp in Malaysia

This research aims to evaluate the performance of grid-connected photovoltaic systems based on three PV technologies along with a composite PV system installed at the rooftop of the engineering tower building, University of Malaya, Kuala Lumpur, Malaysia. The grid-connected PV systems are based on poly-crystalline (p-si), mono-crystalline (m-si), and thin-film (amorphous silicon (a-si)) technologies. The performance evaluation is based on the monthly and annual data that is monitored from January 2016 to December 2019. A comprehensive analysis is conducted on eleven performance parameters such as; performance ratio, capacity factor, array yield, final yield, PV array efficiency, PV system efficiency, inverter efficiency, AC energy, array losses, system, and the overall losses. Results show that p-si based PV system performs better with high annual average (array yield (1309.7 h), array efficiency (12.17%), and system efficiency (11.33%)) accompanied by less degradation in eleven parameters as compared to a-si and m-si PV systems.Moreover, the performance ratios of p-si and a-si PV systems are found higher than the values reported in some of the existing literature studies, subjected to similar and different climatic conditions. The results also indicate that environmentally the composite PV system has the potential to avoid 28143.7 kg of CO2 emissions in four years. This research is expected to deliver valuable statistics to individuals and organizations about the real performance of grid-integrated PV systems in Malaysia, including other tropical climate regions in the world.

Design, simulation and economic evaluation of 90 kW grid connected Photovoltaic system

This paper presents the design, simulation and economic evaluation of a 90 kW grid-connected Photovoltaic (PV) system with nine each subsystem each comprising of 10 kW. This is installed at the rooftop of Electrical Science (ES) building of National Institute of Technology (NIT) Rourkela, Odisha, India. The simulation is performed using PVsyst 6.70 software to design the whole system properly i.e. to select the proper rating of PV panels, Inverter, tilting angle of PV panels, solar azimuth selection, shading calculation, loss calculation, performance, and technical evaluation. To monitor the power generation from the above PV system, a cloud-based data acquisition system has been used. Each of nine numbers of 10 kW grid-connected Photovoltaic (GCPV) systems is designed, simulated and installed at the rooftop of ES building of NIT Rourkela.

Minimization of Energy and Water Cost for the Main Building of Suranaree University of Technology Hospital (SUTH)

Hospitals consume a significant amount of energy and water. Energy and water are intertwined in a way that an improvement of one can worsen the other one. However, as the water price was relatively cheaper in comparison to energy, several studies paid their attention to the minimization of energy usage of the building only. In this research, a study of energy and water for the main building of Suranaree University of Technology Hospital (SUTH) was conducted in order to find the minimum cost of energy and water of the building using proposed a new method namely variables pair. The investigation showed that a single meter of electricity usage as the only energy consumption of the building was applied. Meanwhile, water usage was composed of tap water, flush water, and distilled water. Therefore, a method to determine the cost of energy and water was proposed. A variables pair in a form of (water usage, electricity consumption) was used in the proposed method to determine the cost of energy and water for the main building. Several water-saving options were proposed and examined. It was found that the water and electricity consumptions in the form of variables pair were (82.9 m3/day, 26.3 kWh/day) for a current system, while they were (82.9 m3/day, 21.2 kWh/day) for an option without water regeneration with minimum energy. Meanwhile, they were (82.9 m3/day, 24.4 kWh/day) for a system with water supply tanks allocated at the rooftop and 8th floor of the main building, instead of using only one supply tank installed at the rooftop as in the current system. A system that collects the condensed vapor of the HVAC system and then uses it, had consumptions of (77.3 m3/day, 16.3 kWh/day). Applying the current cost of energy and water at 4.5 Baht/kWh and 10 Baht/m3 respectively it was found that the cost of water could be reduced up to 10.2% with water regeneration. The water cost contributed 7.1% cost reduction, while the energy part was 38.2%. It shows water volume saving is more significant than the energy of water processing saving. The proposed method could separate process and cost parts, therefore it is easy to handle and provides a broader perspective of the saving strategy.

Drone-Based Parcel Delivery Using the Rooftops of City Buildings: Model and Solution

In general, the demand for delivery cannot be fulfilled efficiently due to the excessive traffic in dense urban areas. Therefore, many innovative concepts for intelligent transportation of freight have recently been developed. One of these concepts relies on drone-based parcel delivery using rooftops of city buildings. To apply drone logistics system in cities, the operation design should be adequately prepared. In this regard, a mixed integer programming model for drone operation planning and a heuristic based on block stacking are newly proposed to provide solutions. Additionally, numerical experiments with three different problem sizes are conducted to check the feasibility of the proposed model and to assess the performance of the proposed heuristic. The experimental results show that the proposed model seems to be viable and that the developed heuristic provides very good operation plans in terms of the optimality gap and the computation time.

DESAIN PLTS ATAP KAMPUS UNIVERSITAS UDAYANA: GEDUNG REKTORAT

Utilization of renewable energy is a solution to overcome electricity demand, including PV.PV rooftop can be applied in every building, where solar modules can be placed on the roofbuildings. It also can be done in the University of Udayana Rectorate building because the roof hasthe potential of PV and capable of being a power supply to meet its own needs. This study willdiscuss about the design PV rooftop of the Udayana rectorate building. It simulates the helioscopewith an optimal angle of 14.660 get the result with solar module as much as 135 units with 2inverter pieces of 50 kW the capacity of 45.2 kWp PLTS. While with a sloped roof angle of 15.60get the solar module result as many as 137 units with 2 inverter pieces of 50 kW with PLTScapacity of 45.9 kWp. The calculating production of electric energy produced by PV by simulatingHOMER get the result of PV configuration with Grid capable of supplying electrical energy of304,772 kWh/year, where PV is able to supply at 61,217 kWh/year and Grid supplying electricityenergy of 243,555 kWh/year. The results of the design PV rooftop and calculation results ofelectrical energy production can analyze the economy of the simulation results HOMER with thecost of selling electricity energy PV to PLN in the amount of Rp. 883/kWh can be said to be worthydesigned because it is able to restore the cost of early investment costs PV rooftop of the rectoratebuilding.

Parametric study of URBAN morphology on building solar energy potential in Singapore context

In 2014, the Singapore government announced plans to increase the adoption of solar power, including by integrating solar PV systems into the urban environment. Careful planning of a neighbourhood at early design stage, which determines the overall urban morphology, is important for effective deployment of solar panels in urban environment. This study performed parametric assessment to understand the relationship between urban morphology and the annual average irradiance on rooftop and façade in Singapore context. It also compares the correlation performance of building irradiance with the two definitions of Sky View Factor (SVF). Among the 10 selected morphology parameters, the correlation analysis shows the correlation performances of both definitions of SVF are the strongest ( r = 0.94 to 1). As obtaining the value of SVF is not simple, two multilinear regression predictive models for rooftop and façade irradiance are developed. There is a significant improvement in adjusted R 2 of the rooftop irradiance model (R 2 = 0.61) when comparing the R 2 of other individual parameters (R 2 = 0 to 0.36). It is anticipated that the results of this study 1) would be useful for urban planners considering urban PV integration for sustainable cities; and 2) can provide a simpler way to give a rough estimation of SVF, which is commonly used for the parametric studies related to research areas such as urban microclimate and urban renewable energy utilization. • Among the 10 morphology parameters examined, SEF and SVF have the strongest correlation with building rooftop and façade irradiance. • Apart from the sky exposure performance indicators, H/W ratio is a reasonably reliable indicator for façade irradiance performance.

Seasonality of tropical airborne algae: a 16-month study based on high-throughput sequencing in the Hawaiian Islands

The airborne environment is a critical juncture linking terrestrial and aquatic habitats, yet the algae of this environment are not well-characterised and understood. The goal of this study was to examine seasonality patterns of airborne algae in a tropical environment. Airborne algae were collected monthly in spore traps on a building rooftop on the island of Oʻahu, Hawaiʻi, U.S.A. from December 2015 to March 2017. Metabarcoding of Universal Plastid Amplicon (UPA) and 16S ribosomal RNA (rRNA) markers was used to characterise the algal diversity in the samples relative to meteorological data. Modelled back-trajectories of air masses arriving at the site demonstrated that months with the highest rainfall corresponded to those with the strongest tradewind signal. Thirty airborne algal Exact Sequence Variant (ESV)s were identified using the UPA marker including Cyanobacteria (20), Chlorophyta (4), Streptophyta (3), Chrysophyceae (1), Synurophyceae (1), and unknown Stramenopila (1). Forty-four ESVs were identified using the 16S marker and consisted of Cyanobacteria (43) and plastids of Streptophyta (1). The number and diversity of sequence reads obtained varied strongly both among samples for a given time period and from month to month. Highest rainfall and air temperatures corresponded to months with the largest cyanobacterial relative abundance according to the UPA marker. Although cyanobacteria were the most common group identified using the 16S marker, the dominant cyanobacterial taxon varied by month. Diversity or abundance patterns were not explained by meteorological conditions, which may be due to the relatively small annual amplitude in conditions in the Hawaiian Islands.

Building roof extraction as data for suitability analysis

The geographic potentials of building roofs in urban areas are often under-utilized or sometimes neglected entirely. This is due to the lack of large-scale building roof inventory in the municipality planning offices in African cities. Building rooftops offer great potentials in addressing key urbanization problems such as suitability analysis, disaster management, and others. This paper seeks to demonstrate how remote sensing techniques can be applied to detect and extract building roofs for various suitability analyses (e.g., solar energy and rainwater harvesting) by developing a unique two-in-one technique, which detects and extracts building roof planes and building roof outlines. Using the City of Cape Town, South Africa, as a case study, building rooftops were extracted using the integration of light detection and ranging (LiDAR) data and aerial imagery in an object-based rule-set classification process. This resulted in a building roof inventory, which has crucial attributes of evaluating a building roof for various suitability analyses. The technique developed is well suited for residential and industrial areas where buildings are easily separated from each other. The method and the extracted results were accessed for accuracy and were found to compare well with similar methods already benchmarked.

Numerical investigation of soiling of multi-row rooftop solar PV arrays

The soiling behaviour of multiple solar PV arrays on multi-storey building rooftop was explored using Computational Fluid Dynamics (CFD). The CFD simulation study employed the SST k–ω turbulence model together with the discrete phase model. A grid independency analysis was done to determine the mesh size that is adequate for the simulation study. Three main parameters were investigated in this study on five rows of solar PV arrays and these were wind speed, dust particle size and tilt angle. Airflow characteristics on the solar PV arrays were evaluated and analysed on their influence on soiling. The study revealed that the PV arrays located at the front experience less soiling compared to those located at the rear although there was a small difference of 0.16% in the soiling rate. An average soiling rate of 15.77% was experienced on all the five PV arrays used in the simulation studies. The overall percentage soiling from the front row to the last row was found to be, respectively, 15.85%, 15.82%, 15.77%, 15.74% and 15.69%. A predictive model was developed and had a coefficient of determination, R2 of 96.82% which could accurately predict overall soiling on the PV arrays.

Parametric modeling and surface-specific sensitivity analysis of PV module layout on building skin using BIM

Photovoltaic (PV) energy is a promising source of clean energy that can contribute to the development of sustainable cities and the mitigation of global warming. Conventionally, PV modules were only considered for installation on the rooftop of buildings. However, nowadays there are various types of PV modules that can be installed on different surfaces of buildings, such as curtain walls, windows, and balconies. Given that the productivity of the PV system depends heavily on the layout design (i.e., the size, type, location, and orientation of the modules), it is imperative to perform detailed simulation of radiation potential on different surfaces of the buildings to find the most efficient PV layout. Existing simulation methods, which mostly use only the geometric model of buildings, cannot discriminate between different types of building surfaces. As a result, these methods cannot be used to design PV layouts where different types of surface-restricted PV modules (e.g., PV modules that can be installed on windows) are incorporated. Therefore, this research builds on the advent of Building Information Modeling (BIM) to develop a parametric modeling platform for the design of surface-specific PV module layout on the entire skin of buildings using the surface properties of the BIM model. Using this platform, designers will be able to (1) perform radiation simulation on a combination of desired surfaces of buildings, (2) study the impact of various design characteristics (e.g., size and orientation), (3) develop complex scenarios for the layout of PV modules on the buildings, and (4) perform detailed cost-benefit analysis of each scenario. A prototype is developed using Dynamo visual programming platform to demonstrate the feasibility of the proposed method. A case study is presented for a tall building in Montreal, Canada. Various scenarios are developed and systematically compared from energy and cost perspectives. The case study demonstrated the potentials of the developed platform for the development and in-depth analysis of complex scenarios for the layout of PV modules on building skin. This research contributes to the body of knowledge by demonstrating how BIM can be leveraged towards a more sustainable design of buildings through facilitating the design of complex PV layouts on building skin.

Operational performance of megawatt-scale grid integrated rooftop solar PV system in tropical wet and dry climates of India

This case study presents the performance of a megawatt-scale grid-connected rooftop solar photovoltaic (PV) plant installed on the building rooftops of an educational institute (GITAM Deemed to be University) located in coastal regions (longitude 83° 23' 6.54'' E and latitude 17° 48' 8.208'' N) of Andhra Pradesh. A framework is proposed to validate the existing simulation models that are used for PV project modeling. The validation is done by comparing the simulated performance with the real-time monitored performance. The studied PV plant consists of 3078 solar panels and 23 inverters. For the analysis, we recorded the PV plant operational data for 12 months from 1st October 2018 to 30th September 2019. Based on the monitored data and by following the proposed framework, performance analysis is carried out. The results include the estimated parameters like energy outputs, yield factor, capacity factor, performance ratio, and the error matrices. The solar PV plant supplied energy of 1325.42 MWh to the grid during the monitored period. The expected outcomes of the solar PV plant are assessed using PVGIS, PV Watts, and PV Syst simulation tools. We observed an average mean bias error (MBE) of 5.33% (PVGIS), 12.33% (PV Watts) and 30.64% (PV Syst) and average normalized mean bias error (NMBE) of 2.954% (PVGIS), 7.88% (PV watts) and 22.75% (PV Syst). Overall, it is observed that there is a deviation between the simulated and monitored energy performance.

Vibration and noise studies on wind turbine generator for reduction of vibrations and noise

Purpose Wind power is the one of best natural resources to meet the demands of electricity in India. In this regard, one of engineering college in Visakhapatnam has procured wind turbine generators of 200 kWp and got these installed on the rooftop of the college buildings for research and power generation. After starting the mills, huge vibrations were experienced by the staff and students in the laboratories and classrooms. So, the purpose of this paper is to carry out vibration and noise studies on wind turbine generator to identify the problem for high vibrations and suggest a novel method for vibration reduction. Design/methodology/approach Experimental vibration and natural frequency investigations are carried when wind velocity around 6.0 m/s using frequency analyzer, impact hammer, condenser microphone and accelerometer. An attempt is made to reduce the vibration and noise level of wind turbine generator by inserting a steel coil spring of 300 mm length having 20 turns in series with turnbuckle D shackle assembly, which is used to connect the wind turbine generator to the hook mounted on slab. Findings A high vibration velocity of 9.9 mm/s was observed on at base frame of wind turbine generator. The natural frequencies of hook and slab are observed in between 15 to 20 Hz from the natural frequency test. A high noise of 94.67 dBA is observed at a distance of 1 m from the base of wind turbine generator along the rotational axis of rotor. After modification to the baseline, WTG the vibration and noise levels are reduced to 4.8 mm/sec and 77.76 dBA, respectively. Originality/value This is the first time to study the huge vibrations generated in wind turbine generators installed on the rooftop of the college. Developed a novel methodology to reduce the vibrations by inserting a steel coil springs in turnbuckle D shackle assembly of wind turbine generators. After modification, wind turbine generator are running successfully without any high vibrations.

Big data mining for the estimation of hourly rooftop photovoltaic potential and its uncertainty

The large-scale deployment of photovoltaics (PV) on building rooftops can play a significant role in the transition to a low-carbon energy system. To date, the lack of high-resolution building and environmental data and the large uncertainties related to existing processing methods impede the accurate estimation of large-scale rooftop PV potentials. To address this gap, we developed a methodology that combines Machine Learning algorithms, Geographic Information Systems and physical models to estimate the technical PV potential for individual roof surfaces at hourly temporal resolution. We further estimate the uncertainties related to each step of the potential assessment and combine them to quantify the uncertainty on the final PV potential. The methodology is applied to 9.6 million rooftops in Switzerland and can be transferred to any large region or country with sufficient available data. Our results suggest that 55% of the total Swiss roof surface is available for the installation of PV panels, yielding an annual technical rooftop PV potential of 24±9TWh. This could meet more than 40% of Switzerland’s current annual electricity demand. The presented method for an hourly rooftop PV potential and uncertainty estimation can be applied to the large-scale assessment of future energy systems with decentralised electricity grids. The results can be used to propose effective policies for the integration of rooftop photovoltaics in the built environment.