Rooftop Installations Research Articles

Exploring rooftop solar potential through deep learning: a comparative case study of U-Net and Attention U-Net

Photovoltaic systems are increasingly gaining popularity for rooftop installations in urban areas. These devices contribute to the self-sufficiency of electricity supply and reduce greenhouse gas emissions in urban settings. In this study, we implement deep learning techniques and compare the U-Net and Attention U-Net architectures to detect rooftops in the city of Sidi Bel Abbes (North Africa) for the installation of solar panels. Contrary to trends observed in the literature and previous research, our results show that U-Net achieved a higher accuracy of 90.49%, while Attention U-Net achieved an accuracy of 89.96%. Using the U-Net method, we identified a 1.9-square-kilometer area of rooftops suitable for solar panel installation in the southern part of the town of Sidi Bel Abbes. This discovery represents a potential electrical capacity of 89 MVA, capable of largely satisfying the energy needs of the studied region. This work is a novelty, being the first study of its kind undertaken in Algeria.

City-wide Solar Radiation Potential Analysis by Coupling Physical Modelling and Machine Learning

Abstract. Addressing the challenges posed by climate change and meeting urban energy demands is of utmost importance in today's world. Building Integrated Photovoltaics (BIPV) emerges as a crucial solution for energy conservation and carbon emissions reduction in urban environments. However, traditional methods of assessing solar radiation on buildings using physical models are often computationally intensive and time-consuming. This paper introduces a novel hybrid approach that integrates physical model-based solar radiation calculation with machine learning techniques to analyze Solar Radiation Potential (SRP) across city-wide building infrastructure. The proposed approach precisely evaluates the SRP of representative blocks by leveraging computing-intensive physical models integrated with 3D building data. Subsequently, two machine learning models are developed to effectively predict the SRP of building roofs and facades across the entire city. To validate the efficacy of this approach, an experiment was conducted in Shenzhen, China, yielding insightful results. The findings reveal that Shenzhen has a huge potential for BIPV solar power generation, with mean annual total building roof and facade solar radiation values of 9.22*107 kwh and 2.47*108 kwh, respectively. It can be further observed that relying solely on rooftop installations is insufficient to meet electricity demand. This study not only provides an innovative alternative for city-wide SRP estimation by combining physical modeling and machine learning but also offers valuable insights for fostering low-carbon urban environments and informing data-driven and model-driven urban planning and management strategies.

Performance of Windcatchers in Improving Indoor Air Quality, Thermal Comfort, and Energy Efficiency: A Review

The growing concerns over climate change and energy scarcity have highlighted the need for building energy conservation. Windcatchers, renowned for their effective ventilation capabilities, have emerged as a pivotal solution for saving energy and improving indoor thermal comfort. Serving as rooftop installations, windcatchers harness high-altitude airflow to provide fresh indoor air while expelling stale air. This comprehensive review encompasses over 96 studies published between 2000 and 2024, examining the performance of various types of windcatchers. The review reviews previous articles and concludes that using different types of wind catchers in hot and arid areas can increase indoor air velocity by about 10–50%, reduce building energy consumption by about 20–50%, and increase thermal comfort duration by about 25–50%. The article combines the perspectives of multiple disciplines such as architecture, environmental engineering, and sustainable design, providing a new perspective for the study of windcatchers. The article not only summarizes the design and performance of existing wind catchers, but also provides 13 suggestions for the design of wind capture towers, while also identifying areas for future research, such as combining wind capture machines with other passive cooling technologies and evaluating their performance under different climate and urban conditions.

Development assessment of regional rooftop photovoltaics based on remote sensing and deep learning

Assessing the development of rooftop photovoltaic (PV) plays a positive role in promoting the deployment of solar installations. In response to the problem that previous studies did not consider the PV already installed on rooftops and thus had a low level of refinement, this study proposes a dual-branch framework based on remote sensing imagery and deep learning to effectively monitor the current status and estimate the future potential of regional rooftop PV installations. Based on the dual-branch framework, a semantic segmentation network called MANet is designed that integrated multi-attention modules for more accurate extraction of roofs and PV panels from remote sensing imagery. Finally, the methodology is validated through an application in Taihuyuan Town, Hangzhou City. Model comparisons show that MANet achieves the best accuracy in both roof and PV panel extraction, with IoU scores of 88.17% and 91.58%, respectively. The difference between the existing PV installed capacity and the roof area extracted by the framework and the corresponding statistical data is 8.1% and 11.7%, respectively. The framework calculates the existing rooftop PV installed capacity to be 16,173.74 kW, and estimates the PV installed capacity potential of the remaining rooftops to be 403 MW.

In 50 Shades of Orange: Germany’s Photovoltaic Power Generation Landscape

Spatiotemporally resolved data on photovoltaic (PV) power generation are very helpful to analyze the multiple impacts of this variable renewable energy on regional and local scales. In the absence of such disaggregated data for Germany, numerical simulations are needed to obtain the electricity production from PV systems for a time period and region under study. This manuscript presents how a physical simulation model, which uses open access weather and plant data as input vectors, can be created. The developed PV model is then applied to an ensemble of approximately 1.95 million PV systems, consisting of ground-mounted and rooftop installations, in order to compute their electricity production in Germany for the year 2020. The resulting spatially aggregated time series closely matches the measured PV feed-in pattern of Germany throughout the simulated year. Such disaggregated data can be applied to investigate the German PV power generation landscape at various spatiotemporal levels, as each PV system is taken into account with its technical data and the weather conditions at its geo-location. Furthermore, the German PV power generation landscape is presented as detailed maps based on these simulation results, which can also be useful for many other scientific fields such as energy system modeling.

Energy efficiency in smart schools using renewable energy strategy

As smart schools increasingly rely on technology, achieving energy efficiency becomes crucial for cost reduction and sustainability. This study investigates energy efficiency strategies in smart schools, focusing on the integration of renewable energy technologies. A quantitative approach using numerical simulations and literature reviews establishes benchmarks for energy-efficient smart schools. The Design Builder software is employed to evaluate system performance, with validation achieved through analysis in the System Advisor Model software. The modeled smart school building in Design Builder consumes 75,385.63 kWh annually, based on the weather conditions of specific location. Further studies indicate that integrating photovoltaics and hot water collectors can generate approximately 86,635 kWh annually. This not only offsets the energy consumption of building but also produces an excess of 11,249 kWh, which can be transferred back to the grid for additional revenue. Validation using SAM software demonstrated a minimal difference (3.2%) in annual energy outputs, confirming the accuracy of the model. The findings suggest that photovoltaics and hot water collectors can significantly contribute to achieving net-zero energy consumption in smart school buildings. Additionally, a focus on rooftop installations promotes sustainability by minimizing land use.

Peak Load Shaving of Air Conditioning Loads via Rooftop Grid-Connected Photovoltaic Systems: A Case Study

Over the past few decades, grid-connected photovoltaic systems (GCPVSs) have been consistently installed due to their techno-socio-economic-environmental advantages. As an effective solution, this technology can shave air conditioning-based peak loads on summer days at noon in hot areas. This paper assesses the effect of solely rooftop GCPVS installations on the peak load shaving of commercial buildings in arid regions, e.g., the Middle East and North Africa. To this end, the load profile of a large building with 470 kW of unshaved peak power in Mashhad, Iran (36.2972° N, 59.6067° E) is analyzed after commissioning an actual 51 kW GCPVS. The results of this experimental study, exploiting 15 min resolution data over a year, endorse an effective peak shaving of the GCPVS without employing a battery energy storage system, with 12.2–18.5% peak power shaving on a summer day at noon. The monthly GCPVS self-sufficiency is also 10.2%, on average. In accordance with the studied case’s results, this paper presents valuable insights and recommends actionable policies to regions with similar solar potential and electricity supply challenges, aiming to expedite GCPVS development.

The Decision to Install a Rooftop Photovoltaic System by a Small Business: A Case Study

The potential of rooftop solar power has been identified as a main driver of clean energy adoption in an urban environment. While residential solar projects have lower capacity than commercial systems, residential solar represents most of the installation base for rooftop solar projects. Rooftop solar adoption in the commercial market lags behind residential solar installation. To better understand why this is the case, we conduct a case study of a small manufacturing firm. Based on the firm’s energy demand and the physical attributes of its location, we study a 25-kilowatt solar array using the National Renewable Energy Laboratory’s (NREL) System Advisor Model (SAM). Our empirical study evaluates the economic prospects of a rooftop solar installation project for the firm under study. This analysis sheds light on the financial ramifications of the adoption of solar panels by small, commercial firms in New York state.

Analysis of 1-year energy data of a 5 kW and a 122 kW rooftop photovoltaic installation in Dhaka

Abstract Since 2010, rooftop photovoltaic (PV) systems have been extensively used in Bangladesh. This PV system contributes 2–3% to the country's energy demand. In recent years (2020–2024), at least ten large-scale 20–100 MW PV power plants are coming into operation. However, the growth rate of the new PV system is limited by a few factors, such as sustainable energy output over a long time, financial return on investment, and reliability of the energy. To maintain a steady growth of the electrical energy produced from the PV system, research on the performance of the older installations is required. This study analyzes the various data (generated dc power from sunlight, transmitted ac power to the grid) of a 5 kW (March 2021–February 2022) and a 122.4 kW (January 2022–December 2022) rooftop grid-connected solar installation for 12 months. The polycrystalline silicon PV systems are 8 and 4 years old, respectively. The yearly average performance ratio of the 5 and 122.4 kW systems is 17% and 79%, respectively. The results of the study will encourage the investors and community to achieve a 10% share in the national energy demand in the context of Bangladesh.

Powered by gentrification: The uneven development of residential rooftop solar in Atlanta, Georgia

Rooftop solar is widely seen to be a crucial piece of the puzzle for addressing both greenhouse gas emissions and reducing household energy burdens. But studies from across the United States have consistently pointed to inequalities in the adoption of rooftop solar that limit its ability to address these overlapping problems. This paper examines these social and spatial inequalities in rooftop solar adoption in Atlanta, Georgia, using a novel dataset of residential rooftop solar installation permits from 2018 through 2022. Through this analysis, we demonstrate that while more affluent and white neighborhoods are home to the majority of residential rooftop solar installations within the city, the most significant growth in rooftop solar in recent years has been in majority Black neighborhoods. But by combining these records with an analysis of property-level characteristics and transaction histories, we are able to understand how the installation of rooftop solar, especially in predominantly poorer and Blacker communities, is not, in fact, being driven by a narrowing of racial inequalities in rooftop solar adoption or a greater concern for energy justice. Instead, as gentrification unfolds in previously marginalized neighborhoods, these newcomers become the vanguard of rooftop solar adoption rather than longstanding residents who would have the most to gain from such technologies. This paper ultimately clarifies the distinction between spatial redistribution and social redistribution of renewable energy, and the need for both finer-grained analyses of inequalities in clean energy access and adoption and a greater commitment towards both energy and housing justice.

Analysis of noise distributions at heliports and vertiports: A guide for site selection and land use planning

Purpose: The purpose of this study was to examine the noise profiles of helicopters and eVTOLs at heliports and vertiports in order to support site planning and the development of local land-use compatibility guidelines. Design/methodology/approach: This study used existing helicopter and eVTOL sound profiles to develop noise distribution contours for heliports and vertiports. This study collected noise data from available studies on helicopters and eVTOLs. This data was then entered into dBmap noise mapping tool to develop noise maps for helicopters and eVTOLs. Three air transit facility configurations for each aircraft category were analyzed: open (unobstructed), urban, and rooftop. Two additional vertiport configurations were created by overlaying building and noise data with Google Earth imagery. Noise data was entered into dBmap for processing. Noise contours were mapped for three configurations for both aircraft categories.Findings: Key observations from the noise distribution analysis showed that open (unobstructed) facility configurations have even noise distributions for both eVTOLs and helicopters. Noise maps for urban locations showed areas of attenuation and asymmetrical patterns due to the interactions of sound waves with surrounding buildings. An analysis of a rooftop installation of a heliport or vertiport provided some noise mitigation advantages. Noise contour distributions closely matched those outlined in previous research; however, the sound intensities modeled in this study were lower than indicated in exigent research. Assessments were also conducted for real-world sites with potential future use as vertiports in Seattle, Washington, and Chicago, Illinois.Practical Implications: This study suggests that current land use compatibility guidance may be inadequate for rotorcraft and eVTOL operations. Findings suggest the development of symmetrical noise-impact zones centered around heliports and vertiports. Examples of these zones are outlined, and recommendations for future research are provided. Local planners can use the data from this study to make educated choices about the siting of heliports and vertiports. Additionally, the findings can assist planners in the development of zoning and land use compatibility standards.Social Implications: Land use compatibility standards for heliports and vertiports will help ensure a synergistic relationship between local communities and these air transit facilities. The data from this study can also help protect individuals from excessive noise and annoyance.Originality/value: This study is one of the few on this topic and the only known research on noise distributions of helicopters and eVTOLs with a particular focus on land use compatibility

Assessing the Potential of Qatari House Roofs for Solar Panel Installations: A Feasibility Survey

Qatar’s ambitious Vision 2030 includes a major shift towards clean energy, and residential solar PV installation can be an obvious option, given its abundant sunlight and high power for residential cooling. Despite significant solar panel farm investment, there has been limited progress in deploying solar panels on home roofs, and further research is needed to identify the potential for such an initiative and its impact on the country’s move towards clean energy. This field survey assesses the potential for residential rooftop solar panel installation across Qatar, considering space availability, currently utilized space, remaining space, shading, and roof type. It also provided indications of potential obstacles and shading that might affect panel sunlight exposure. The results showed that there is significant potential for installing solar panels on Qatari homes, which could contribute to a considerable portion of the energy consumed by households during peak usage periods, particularly in the summer months. Moreover, excess energy generated could be exported to other countries with high demand during periods of low demand in Qatar. The study’s findings complement previous research efforts and provide insights for policymakers and stakeholders to develop strategies that endorse the vision for 2030 and promote the transition towards clean energy in Qatar.

Artistic Intervention as Scene Construction/Deconstruction: An Analysis of the Display of the Kangxi Throne in the Humboldt Forum in the Context of the Cross-Cultural Exhibition

Based on the research perspective of cross-cultural exhibition analysis, this paper takes case study as the fundamental methodology under the framework of museology and art history research in order to analyse the new display of the Kangxi throne and its screen, which were lost overseas from China during the war years and have been transferred from the Museum of Asian Art in Dahlem to the Humboldt Forum, which is deeply involved in the controversy of its colonial history. This study primarily focuses on the situational methods in which the exhibits were connected to the public under artistic intervention. In the exploratory stage, the “Game of Thrones” project in the Humboldt Lab Dahlem programme offered multiple versions of interpretations, which ultimately prompted the museum to change the scene restoration plan and invite the famous Chinese architect Wang Shu to complete the rooftop installation. Between construction and deconstruction, the artwork’s scenic intervention creates structural descriptions for the presentation of cross-cultural differences, and accommodates ethical conflicts from different sides with its poetic, distanced interpretations, while providing a shared language for comprehending the various facets of nationhood amidst the intersection of history and the present.

Comparing PV-green and PV-cool roofs to diverse rooftop options using decision analysis

Flat roofs can employ a range of technologies to improve sustainability, such as photovoltaic (PV) panels, green roofs, cool roofs, or a combination of these options. Yet, weighing the benefits, costs, and performance of different roofing technologies is complex, especially when different stakeholders are involved. Decision analysis techniques, such as multi-criteria decision analysis (MCDA), can be used to systematically evaluate a diverse range of rooftop options to assess trade-offs in a quantitative way and avoid decision biases. This study offers a holistic comparison of different roof types, considering stakeholder preferences and uncertainty using MCDA. Ten flat roof options are compared, including black, gravel, cool, extensive green and semi-intensive green roofs, each with or without a rooftop PV installation, for nine objectives and three hypothetical stakeholder profiles. Performance is evaluated using building energy simulation, hydrologic modeling, and literature research. Uncertainty analyses are used to evaluate the effects of model assumptions on the MCDA results. For assumed preferences of an urban planner and environmentalist, semi-intensive green roofs with integrated PV installation are the best performing option; however, for a hypothetical building owner more concerned with costs, a gravel roof with PV ranks best. Uncertainty plays a role in the results, in particular, the uncertainty of the predicted outcome of options for the building owner, which can change the top-ranking options considerably. The uncertainty analyses are useful to identify consensus options over all three stakeholder types. Despite considerable uncertainty, extensive and semi-intensive green roofs with PV are recommended as relatively robust best-performing options.

Impacts of Rooftop Photovoltaics on the Urban Thermal Microclimate: Metrological Investigations

Ambitious climate protection requires decentralized renewable energy production via building-related photovoltaics in cities. However, cities are also subject to the Urban Heat Island effect, which negatively impacts human health. In this context, the installation of PV modules in urban areas raises the question of how the energy-active building component affects its surrounding thermal microclimate. The topic is approached with a novel, twofold methodology: First, a horizontal ambient air temperature profile above a rooftop PV installation and the analysis of surface temperatures provide primal indications of the impacts of PV on the thermal microclimate. Secondly, establishing energy balances allows us to retrace the energy fluxes. The data required for the comparative analyses are gathered through metrological investigations of two rooftops with and without PVs in Munich, Germany. The results of the investigation show a daytime heating effect of photovoltaics on the ambient air temperature of up to +1.35 K and a nighttime cooling effect of up to −1.19 K. Cumulated daily, the daytime heating effect exceeds the impact of the nighttime cooling. The main driver of the heating and cooling is the additional convective heat transfer from the PV modules. However, the impacts of the PV modules are marginal and restricted to their direct surroundings.

A Comparative Analysis of Measured and Simulated Data of PV Rooftop Installations Located in Poland

In recent years, photovoltaics (PVs) is the main driver of the renewable energy market growth in Poland. The number of photovoltaic installations, most of which are rooftop prosumer systems, is consistently growing. Therefore, the determination of the applicability and feasibility of photovoltaic systems under different climate conditions is of great significance. This study presents the performance analysis of four prosumer photovoltaic installations situated in the Eastern part of Poland, Lublin Voivodeship. The influence of various tilt angles, ranging from 19° to 40°, and azimuths (south, east, south–east, and east–west) on the final yield have been determined under one year of operation (2022). The average yearly final yield was found to be 1022 kWh·kW−1, with the highest value obtained for the installation oriented towards the south, equal 1079 kWh·kW−1. Then, the PV systems were simulated by the use of four specialized photovoltaic software: DDS-Cad 16, PVGIS 5.2, PVSOL premium 2022, and the PVWatts Calculator 8.2.1. A comparative analysis of the measured and simulated data in terms of the final yield was carried out. The data obtained from PVGIS and PVSOL demonstrated the highest degree of overall alignment of 92% and 91%, respectively. The most significant underestimation was noticed for the DDS-Cad software, which was equal to 77%. The most accurate predictions stand out for the system oriented to the south, while the weakest was found for the E–W installation.

Comprehensive Research on the Near-Zero Energy Consumption of an Office Building in Hefei Based on a Photovoltaic Curtain Wall

The near-zero energy design of a building is linked to the regional climate in which the building is located. On the basis of studying the cavity size and ground height of a photovoltaic curtain wall, the power generation efficiency of the photovoltaic curtain wall under different ground heights is compared in this paper. According to the “Technical Standard for Near-Zero Energy Buildings”, the personnel and lighting of a 12-metre office building in Hefei were parametrically arranged and three design schemes for near-zero energy buildings were proposed. The energy consumption of the benchmark building and the design energy consumption of each scheme were calculated by using the energy consumption simulation software Design Builder V 7.0.0.096; the feasibility of realizing the near-zero energy consumption building by using each scheme was checked. The results show that when the cavity width of the photovoltaic curtain wall of the office building is 70 mm, the cavity heat transfer coefficient is the lowest and the heat insulation of the building is the best. When the height from the ground is 0.7 m, the power generation efficiency of the photovoltaic curtain wall reaches a maximum of 18.39% and the south façade of the building is more suitable for the layout and installation of the photovoltaic curtain wall. The single-façade photovoltaic curtain wall should be combined with a high-efficiency air conditioning system and lighting system; the installation of a photovoltaic rooftop at the same time can meet the design requirements of near-zero energy buildings in hot-summer and cold-winter areas. This paper provides some guidance for exploring the design of near-zero energy office buildings, which is of practical significance.

Carbon, indoor air, energy and financial benefits of coupled ventilation upgrade and enhanced rooftop garden installation: An interdisciplinary climate mitigation approach

Building energy use contributes to urban carbon dioxide (CO2) emissions while inadequate ventilation can yield indoor CO2 build up from human respiration. However, increasing ventilation rates can add to energy costs and climate burdens. Our objective was to quantify changes in emissions, energy, and financial cost when rooftop garden and ventilation upgrades are done simultaneously, with an opportunity to enhance plant growth from exhausted CO2. We measured indoor CO2 concentrations, calculated ventilation rates, and modeled five scenarios to assess these impacts. The indoor CO2 concentration maximum was 2210 ppm, median was 840 ppm, and 33% of the daytime was spent above 1000 ppm. The estimated ventilation rate was 4 L/s. Our model calculations show that increasing ventilation to recommended levels (7 L/s) would increase total CO2 emissions, energy use, and cost (1–4%), but this could be counterbalanced by rooftop garden installation benefits, which yielded a net decrease of 23–46% in CO2 emissions, 12–13% in energy use, and 12–16% in cost. This novel integration of data collection and modeling provides support for the co-benefits of simultaneous improved installation ventilation systems and indoor CO2-enhanced rooftop gardens.

Centralized MPPT based on Sliding Mode Control and XBee 900 MHz for PV systems

Maximum Power Point Tracking (MPPT) algorithms are essential to achieve the best overall performance of PV systems. Typically, MPPT techniques are implemented over wired communications, which connect sensors, computing nodes and DC–DC converters. However, the introduction of wireless communication systems can offer more flexibility for information collection, dissemination, and processing when compared with wired communication infrastructures. This article proposes a wireless control architecture that allows the execution of the MPPT algorithms for several PV subsystems on a central node with limited computing power. This approach introduces flexibility and optimizes energy production at PV systems. The presented approach uses Current and Voltage measures, as well as the Irradiance and Cell Temperature values obtained at the PV panel, to calculate the optimal PWM duty cycle for the DC–DC converter which extracts the maximum power from the PV modules. Wireless communications are implemented by means of XBee 900 MHz RF modules. These modules provide a low cost solution with a relatively long range communication, avoiding the overpopulated 2.4 GHz band, in which other common technologies may cause interferences. Although the proposed approach allows the use of different control algorithms, Sliding Mode Control (SMC) techniques were selected, since this control technique ensures robustness and low computational complexity. The proposed SMC was simulated and compared with other conventional techniques with low computational cost, namely PID and P&O. Simulation results proved that SMC provides better performance and higher robustness when sudden changes in irradiance occur. The presented approach was experimentally tested in a PV rooftop installation at the Faculty of Engineering of Vitoria-Gasteiz. The obtained results suggest that it may be a valid way of maximizing energy production in PV systems while avoiding the constraints of wired communications.

Decarbonization Program through an Implementation of 411 kWp OFFGRID PV Rooftop in reducing GHG in Muara Karang Combined Cycle Power Plant

The Indonesian government commits to reducing greenhouse gas emissions by following the Paris Agreement to the Nations Framework Convention on Climate Change. Indonesia targets to reduce GHG emissions by 29% by 2030 with business as usual and 40% with international assistance. PT PJB Muara Karang in Jakarta has operated PV Rooftop with a total capacity of 411 kWp which is one of the renewable energy sources. The solar plants have been installed on the roof of an office building aimed at own-used. Calculation of the reduction of greenhouse gas emissions uses the reference CDM AMS I.D Version 18.0. By using this method, the reduction in greenhouse gases was approximately 158,93 ton CO2 from January 2021 to June 2022. This program can generate 411,839.7 kWh of Electricity. As a solution to reduce coal-fired power plants, in the long term, the company (PT PJB) has a target of developing New Renewable Energy of 3394 MW by 2030. The rooftop PV installation program for own use is one of the company’s commitments to reduce greenhouse gases and support the achievement of the targets energy mix for renewable energy. This program is expected to be claimed as a form of decarbonization program.