Building-applied Photovoltaics Research Articles

Exploiting building information modeling and machine learning for optimizing rooftop photovoltaic systems

The primary objective of this study is to develop a strategy to maximize the potential of Building Applied Photovoltaics (BAPV) by providing researchers and experts in the field with the appropriate tools. By utilizing operational data from an operational roof-mounted BAPV system and incorporating Building Information Modeling (BIM) to improve its design and smooth integration into built settings, the study offers novel insights.A three-phase research methodology is applied, encompassing data collection and performance assessment, BIM modeling, and machine learning algorithms for energy forecasting. The case study involves a 160 kWp photovoltaic system in Abruzzo, Italy, over a three-year period. The research employs different performance metrics recommended by IEC 61724 to compare experimental and theoretical data. BIM simulations are exploited as they are crucial for identifying the correct design process. Furthermore, four cutting-edge machine learning algorithms are used to forecast daily energy production. The random forest is identified as the best model for forecasting and the effect of tuning of hyperparameters on the efficiency of all models is also reported.The research adds to the larger conversation on sustainable energy management and solutions by providing researchers involved in the design and improvement of BAPV systems with a solid foundation for future developments.

Assessment of building energy performance integrated with solar PV: Towards a net zero energy residential campus in India

Building Applied Photovoltaics (BAPV) such as Roof-top Solar PV has gained significant attention in recent years for harnessing the untapped potential of renewable energy sources. However, rooftop PV poses hurdles of space restriction and shadowing in densely packed urban residential neighborhoods. This study aims to design and assess the feasibility of an integrated grid-connected Rooftop and Façade Building Integrated Photovoltaic (BIPV) for meeting the energy demand of residential buildings on an academic campus. Three distinctive groups of residential typologies have been investigated in this study, categorized based on built area and occupants’ past energy usage. Additionally, the variation in the measured Energy Performance index of the three different residential groups is illustrated to pave the path for the development of a typology-based residential energy benchmarking and labelling system. The Solar PV system has been designed for the maximum household energy demand recorded in CoVID-affected years due to high residential electricity usage in this period. The study showcases that integration of façade BIPV for low-rise residential buildings increases the system energy production to up to 62.5 % based on the utilized surface area for active PV. Furthermore, the Net Zero Energy Building (ZEB) potential for each typology has been achieved by integration of the proposed Solar PV, evaluated as a function of the Energy Performance Index (EPI) and Energy Generation Index (EGI). The designed nominal PV power of the proposed grid-connected plant is 5.6 MW, producing 7182 MWh annually, meeting the maximum residential energy demand in the studied academic campus in CoVID affected year.

Assessment of soiling impacts and cleaning frequencies of a rooftop BAPV system in composite climates of India

As one of the pioneers in solar photovoltaic (SPV) installations, India has witnessed several challenges related to performance; dust accumulation is one among them which needs attention. On the other side, most installers and SPV system owners do not have informed knowledge of dust accumulation rates (DAR) and optimum cleaning frequencies (OCF). It is also a well-known fact that DAR varies based on the SPV system (e.g., ground-mount, roof-mount, building applied/attached, building integrated and many other types). Hence, this paper analyses the effect of soiling specific to rooftop building-applied photovoltaics (BAPV) systems, and the main objective is to estimate the OCF driven by DAR. A rooftop BAPV system installed in India's composite climate zone is chosen as a case study, and its daily performance is monitored. Also, the on-site DAR is measured with micro slides help each day. It is observed that the system has different DAR for different seasons, clearly showing the relationship between energy outputs and DAR. The annual average daily deposition rate of dust was measured as 0.122 gm/m2/day. The maximum soiling loss of 0.39%/day was recorded in spring, followed by 0.34%/day in winter. The minimum soiling loss of 0.24%/day was measured in monsoon owing to heavy rainfall. The rooftop BAPV optimum cleaning frequency has been determined based on the energy lost due to soiling and cleaning cost. Overall, this study reveals that the rooftop BAPV system needs cleaning twice a year, first in spring and second in winter.

Infrared Thermography in Maintenance of Building Applied Photovoltaics

Photovoltaic Systems (PV) are the most widely used renewable energy source in the Republic of Croatia but with a modest share in the total energy balance. EU energy policy encourages PV installation in building elements such as facades, roofs or separate constructions with the aim of achieving zero-energy buildings. Whether an integrated or stand-alone system during their lifetime requires periodic maintenance. In a normal operation, it is necessary to carry out a visual inspection twice a year before and after the winter period to determine the condition of the equipment, connecting lines and supporting structures. In the case of a significant deviation from the normal production, the inspection must be done as soon as possible. Most commonly, the problems of the unmaintained system cannot be perceived as long as the PV system is in an operational state. Dropping of dust, bird droppings or shading over a longer period may lead to system components being damaged and to necessary repair costs that can be prevented by regular maintenance procedures, including regular surface cleaning of photovoltaic panels. Infrared thermography is a fast method of detecting heat sources due to shading or defective photovoltaic module elements. The paper provides visual examples of thermal spots that can be observed during the infrared thermographic inspection of photovoltaic systems, as well as a review of their impact on the system.

Identification of Factors Influencing Development of Photovoltaic (PV) Implementation in Singapore

Despite the steady growth of grid-connected installed capacity in Singapore in the last decade and intensive government effort towards “solarization”, implementation of photovoltaics (PV) and especially building-integrated photovoltaics (BIPV) into the built environment has not gathered as much momentum as would have been expected given the country’s ample solar energy resource potential, strong economic fundamentals and the robust real estate sector. Based on a conducted web-survey and qualitative interviews among local professionals, this paper examines the obstacles, potentials and drivers that could facilitate and accelerate BIPV and PV façade integration, as well as needs that could encourage wider PV use. In order to define a unified strategy, aligning the stakeholders’ views, the following disputable factors are pointed out and discussed: (1) incomplete understanding of BIPV and building-applied photovoltaics (BAPV) among stakeholders, (2) costs of BIPV systems, (3) low awareness of and confidence in “integrability” of PV modules, (4) incomplete knowledge about and insufficiently investigated PV performance and (5) potential of PV façade and roof integration. Since the costs are the key identified factor for BIPV implementation, life-cycle cost (LCC) assessments of PV façade and roof integrations have been performed, which supported the search for solutions to identified problems. The performed analysis and findings present the basis for the development of a long-term holistic strategy for PV implementation in Singapore that could help the highly-urbanized, tropical resource- and land-constrained island city-state reduce the dependency on fossil fuels and achieve the climate change targets, thus promoting a more sustainable built environment.

Photovoltaic systems – types of installations, materials, monitoring and modeling - review

Photovoltaic systems have become a common solution for, both small residential buildings as well as large service buildings. When buildings are being designed, it is important to focus on the aspect of the object’s energy efficiency as lowering the energy consumption of a given facility is crucial. The article discusses the use of photovoltaic panels such as so-called BAPV (Building Applied Photovoltaics) and BIPV (Building Installed Photovoltaics) installations as well as photovoltaic thermal systems (PV/T), which generate both electricity and heat. The role of PV installation in so-called zero energy buildings and proposals for future research and solutions are also discussed.

Review on Building-Integrated Photovoltaics Electrical System Requirements and Module-Integrated Converter Recommendations

Since building-integrated photovoltaic (BIPV) modules are typically installed during, not after, the construction phase, BIPVs have a profound impact compared to conventional building-applied photovoltaics on the electrical installation and construction planning of a building. As the cost of BIPV modules decreases over time, the impact of electrical system architecture and converters will become more prevalent in the overall cost of the system. This manuscript provides an overview of potential BIPV electrical architectures. System-level criteria for BIPV installations are established, thus providing a reference framework to compare electrical architectures. To achieve modularity and to minimize engineering costs, module-level DC/DC converters preinstalled in the BIPV module turned out to be the best solution. The second part of this paper establishes converter-level requirements, derived and related to the BIPV system. These include measures to increase the converter fault tolerance for extended availability and to ensure essential safety features.

Performance comparison of BAPV and BIPV systems with c-Si, CIS and CdTe photovoltaic technologies under tropical weather conditions

This paper compares the performance of photovoltaics (PV) for building applications in two configurations: building applied photovoltaics (BAPV) and building integrated photovoltaics (BIPV). A 32.7 kWp PV capacity is proposed for a roof building and its performance in BAPV and BIPV configurations with three PV technologies namely crystalline (c-Si), CIS, and CdTe is analyzed. The standard methodology with performance parameters such as energy yield (EY), yield factor (YF), capacity utilization factor (CUF), performance ratio (PR), and losses is used. It is found that the EY, YF, and year to year energy production variability of BIPV and BAPV technologies varies from 43,700–46,800 kW h, 1336.39–1431.19 kW h/kWp, and 1910–2100 kW h respectively. The CUF and PR vary from 15.25–16.33%, and 72.23–77.36% respectively. Irrespective of PV configuration and technology, observed losses due to the angle of incidence, spectral effects, effects of change in irradiance and module temperatures are observed to be − 2.8%, − 1 to − 5%, and − 7.4 to − 13.6% respectively. Total system losses range from −22.6 to 27.8% causing a fair amount of loss in the PV efficiency. Among, three PV technologies, CdTe is observed to perform better than CIS, and c-Si.

Dust cleaning robots (DCR) for BIPV and BAPV solar power plants-A conceptual framework and research challenges

This paper proposes a conceptual framework to design and develop robots for addressing the soiling or the dust cleaning issue on the building integrated photovoltaics (BIPV) and building applied photovoltaics (BAPV). BIPV and BAPV turn the present and future buildings (high rise or low rise) into power stations with the introduction of photovoltaics either in the façade (90° wall) or roof (flat or pitched) configuration. But one of the significant challenges that influence the energy performance is the dust accumulation. This is a serious issue in the places where air pollution is very high. Addressing this would be very difficult for the human workforce, and the complexity and tediousness would increase depending on the size of the BIPV and BAPV array or the height of the building. Currently, there are few dust cleaning robots which could offer services in addressing the soiling issues in conventional photovoltaic installations. The existing dust cleaning robots (DCR) could not offer a better feasible solution in BIPV and BAPV as they offered in traditional PV systems that were installed in an open area. Hence for addressing dust cleaning issue, some novel conceptual schemas related to robot developments were proposed in this paper considering the installation configuration of PV systems for building applications. Here, DCR’s for three configuration of PV installation with building applications namely BIPV/BAPV façade, BIPV/BAPV horizontal roof, and BIPV/BAPV pitched roof are dealt. The proposed conceptual robots were briefly described with the schematic views highlighting operation, energy consumptions, and slipping issue etc. Scope for the development and various research challenges that are to be considered during the design stage are highlighted along with the discussion

Studi Kasus Kelayakan Penerapan Sistem Hybrid Building Applied Photovoltaics (BAPV)-PLN pada Atap Gedung Politeknik Aceh

With the undeveloped BAPV(Building Applied Photovoltaics) at Office Building and Public Facilities, Caused the high price of solar modules and the lack the economic study on the use of solar modules that housed in the Banda Aceh region. Furthermore, the price of solar modules is expensive, so people think it will cost so much funds to building a BAPV’s system. These problems could be overcomed if the existing technical studies and economic studies of the application of the BAPV’s system. This study aims to assess the application of the BAPV’s system on institutions building in terms of technical and economic value, in this case the building that is used as the study object is the Polytechnic Aceh’s Building. The method that used in the technical studies are theoretical calculations and simulations using helioscope software, while the methods used for economic studies is using the methods of cost-benefit analysis ( cost benefit analysis). The method used to find the NPV (Net Present Value), PP (Payback Period), IRR (Internal Rate of Return), and BCR (Benefit Cost Ratio). If the average value of solar radiation reaching 4.79 kWh / m2 / day and the average daily energy requirement is 592 kWh, the energy generated from BAPV-PLN hybrid system on the roof of the object building will reach the amount of 237 MWh/year with the capacity charge controller used is 7490 A and the capacity of the battery used is 64.487 Ah. Panel tilt angle used is 25 o and the type of panel used is Monocrystalline manifold. From the economic value will obtained NPV value of Rp. 20.022.106.937, PP during 5,2 years, IRR of 36% and 3,49 of BCR. Based on the evaluation results of the feasibility study, the project of hybrid BAPV-PLN’s system on the roof of the Polytechnic Aceh’s building can be realized, because its already meet the criteria of the feasibility study to make the systems get established in real term.

Organizational Challenges in the Adoption of Building Applied Photovoltaics in the Swedish Tenant-Owner Housing Sector

Sweden has committed itself to comply with EU-directive 2009/28/EC on energy from renewable sources and 2012/27/EU on improvement in the efficiency of energy. Measures in the existing housing stock, such as installing photovoltaics (PV), provide a means of contributing to the goals above. The purpose of this paper is to study how the organization of property management and the decision-making structure in tenant-owner cooperatives (TOCs) in Sweden facilitates or hampers the adoption of large-scale residential building applied photovoltaics (BAPV) in this housing sector. Data collected through seven semi-structured interviews of executive board members in seven housing cooperatives were descriptively analyzed and the results indicate that the decision to adopt BAPV in TOCs does not follow the common frameworks of adoption of innovations. The choice by TOCs to adopt BAPV depends more on the wish to lower operating costs than on efforts to promote a sustainable environment and various principal-agency problems during the decision-making process, as well as during the implementation phase create challenges to the adoption of BAPV. There is a need to strengthen the quality and management of knowledge, as well as procurement proficiency in the TOCs in order to harness the potential for BAPV in the sector.

Limitations in solar module azimuth and tilt angles in building integrated photovoltaics at low latitude tropical sites in Brazil

Photovoltaic (PV) generation depends directly on the amount of radiation received by solar modules at a given temperature, and annual irradiation varies according to site location and PV array position. In this paper, the limitations and the solar irradiation levels received by building surfaces in different positions (with azimuth and tilt angle variation) in capital cities in Brazil are shown, making use of the Brazilian global horizontal solar irradiation data provided by the SWERA (Solar and Wind Energy Resource Assessment) project. These data were processed to generate figures on the irradiation at various PV module orientations and slopes for each city, which show the relative radiation levels received on specific azimuth and tilt angles in relation to the ideal position. Results were validated using four real and operating PV systems. In general, variations in azimuth or slope did not cause large annual irradiation losses up to around 20° tilt angles. This shows to PV system planners that under these fairly flexible conditions it is possible to install PV on any orientation, keeping high levels of annual irradiation, and that limitations in orientation and tilt can be relatively low. It also allows a quick analysis of PV retrofit in building-applied photovoltaics (BAPV), when seeking the best building surfaces to incorporate PV.

Performance compromises of building-integrated and building-applied photovoltaics (BIPV and BAPV) in Brazilian airports

Civil aviation is a large and growing contributor to greenhouse gas emissions. The airports that host commercial flights are often national landmarks and architectural showcases. They are typically large, horizontal and free of shading, and are also ideally suited for the integration of photovoltaic (PV) systems for onsite generation of clean and renewable electricity. While ground-mounted PV generators should be designed for optimum performance, PV systems integrated on buildings should also consider aesthetics. We have analysed building-applied and building-integrated PV systems (BAPV and BIPV). In BAPV, optimised PV module orientation and tilt angles were proposed for maximum annual output, while in BIPV, modules were accommodated respecting the existing architecture of airport buildings. Two Brazilian airports were analysed, comparing the performance of BAPV and BIPV using two “off-the-shelf” PV technologies. On average, both the installed peak power and the energy generation density were found to be higher for BIPV (100% and 87%, respectively), while the final annual energy yield was 7% higher for BAPV. A compromise of pleasant integration and small energy losses was reached, which can assist in convincing clients and the public more than an ideally tilted and oriented PV generator that impacts negatively on the building's aesthetics.

The potential of building-integrated (BIPV) and building-applied photovoltaics (BAPV) in single-family, urban residences at low latitudes in Brazil

The integration of solar modules on buildings’ roofs and façades is one of the most elegant applications of photovoltaics (PV). With the declining costs of this technology, building-integrated and building-applied photovoltaics (BIPV and BAPV) can efficiently and cost-competitively assist in delivering electricity in urban environments. We have quantified the potential of BIPV and BAPV generators on existing single-family detached residential buildings in Florianopolis–Brazil (latitude 27°S, solar irradiation 1550kWh/m2/year), in supplying each house and a fraction of the local utility feeder's electricity demands. We have measured and compared the annual output performance of thin-film amorphous silicon, and traditional crystalline silicon solar PV technologies, and proposed solar PV kits to be installed on all of the existing 496 residential buildings roof tops in the mixed residential–commercial area studied. The typical single-family, detached home roof covers can easily accommodate the proposed PV kits, with 87% of these generators yielding at least 95% of the maximum theoretical generation output of an ideally oriented and tilted PV system. Low-pitched, existing roof covers in residential houses represent excellent areas for PV integration at low latitudes. Installing BIPV on all of the available roof areas can make each and every house a net energy-positive building.