Search Results (151)

Dynamic and Adaptive solar systems demonstrate a greater potential to enhance the satisfaction of occupants, in terms of indoor environment quality and the energy efficiency of the buildings, than conventional shading solutions. This study has evaluated Dynamic and Adaptive Photovoltaic Shading Systems (DAPVSSs) through a comprehensive analysis of six shading designs in which their energy production and the comfort of occupants were considered. Energy generation, thermal comfort, daylight, and glare control have been assessed in this study, considering multiple orientations throughout the seasons, and a variety of tools, such as Rhino 6.0, Grasshopper, ClimateStudio 2.1, and Ladybug, have been exploited for these purposes. The results showed that the prototypes that were geometrically more complex, designs 5 and 6 in particular, had approximately 485 kWh higher energy production and energy savings for cooling and 48% better glare control than the other simplified configurations while maintaining the minimum daylight as the threshold (min DF: 2%) due to adaptive and control methodologies. Design 6 demonstrated optimal balanced performance for all the aforementioned criteria, achieving 587 kWh/year energy production while maintaining the daylight factor within the 2.1–2.9% optimal range and ensuring visual comfort compliance during 94% of occupied hours. This research has established a framework that can be used to make well-informed design decisions that could balance energy production, occupants’ wellbeing, and architectural integration, while advancing sustainable building envelope technologies. Full article

Distributed photovoltaic (PV) generation is increasingly important for urban energy systems amid global climate change and the shift to renewable energy. Traditional PV deployment prioritizes maximizing energy output, often neglecting electricity price variability caused by time-of-use tariffs. This study develops a high-resolution planning and economic assessment model for building-integrated PV (BIPV) systems, incorporating hourly electricity real-time market prices, solar geometry, and submeter building spatial data. Wuhan (30.60° N, 114.05° E) serves as the case study to evaluate optimal PV placement and tilt angles on rooftops and façades, focusing on maximizing economic returns rather than energy production alone. The results indicate that adjusting rooftop PV tilt from a maximum generation angle (30°) to a maximum revenue angle (15°) slightly lowers generation but increases revenue, with west-facing orientations further improving returns by aligning output with peak electricity prices. For façades, south-facing panels yielded the highest output, while north-facing panels with tilt angles above 20° also showed significant potential. Façade PV systems demonstrated substantially higher generation potential—about 5 to 15 times that of rooftop PV systems under certain conditions. This model provides a spatially detailed, market-responsive framework supporting sustainable urban energy planning, quantifying economic and environmental benefits, and aligning with integrated approaches to urban sustainability. Full article

This research proposes an integrated lighting and solar shading strategy to improve energy efficiency and user comfort in a retrofit project in a temperate-humid climate. The study examines a future library addition to an existing faculty building in Bursa, featuring highly glazed façades (77% southwest, 81% northeast window-to-wall ratio), an open-plan layout, and situated within an unobstructed low-rise campus environment. Trade-offs between daylight availability, heating, cooling, lighting energy use, and visual and thermal comfort are evaluated through integrated lighting (DIALux Evo), climate-based daylight (CBDM), and energy simulations (DesignBuilder, EnergyPlus, Radiance). Fifteen solar shading configurations—including brise soleil, overhangs, side fins, egg crates, and louvres—are evaluated alongside a daylight-responsive LED lighting system that meets BS EN 12464-1:2021. Compared to the reference case’s unshaded glazing, optimal design significantly improves building performance: a brise soleil with 0.4 m slats at 30° reduces annual primary energy use by 28.3% and operational carbon emissions by 29.1% and maintains thermal comfort per ASHRAE 55:2023 Category II (±0.7 PMV; PPD < 15%). Daylight performance achieves 91.5% UDI and 2.1% aSE, with integrated photovoltaics offsetting 129.7 kWh/m² of grid energy. This integrated strategy elevates the building’s energy class under national benchmarks while addressing glare and overheating in the original design. Full article

The integration of energy-active elements into the building envelope in the form of large-area heating/cooling, active thermal protection (ATP), thermal barriers (TB), and TABS represents a technical solution that is consistent with the principles of energy sustainability, resilience, and adaptability to climate change and ensures affordable and clean energy for all while protecting the climate in the context of the UN Sustainable Development Goals. The aim and innovation of our research is to develop energy multifunctional facades (EMFs) that are capable of performing a dual role, which includes the primary known energy functions of end elements and the additional innovative ability to serve as a source of heat/cooling/electricity. This new function of EMFs will facilitate heat dissipation from overheated facade surfaces, preheating of hot water, and electricity generation for the operation of building energy systems through integrated photovoltaic components. The theoretical assumptions and hypotheses presented in our previous research work must be verified by experimental measurements with predictions of the optimal operation of building energy systems. Most existing studies on thermal barriers are based on calculations. However, there are few empirical measurements that quantify the benefits of ATP in real operation and specify the conditions under which different types of ATP are feasible. In this article, we present the development, design, and implementation of an experimental prototype of a prefabricated building module with integrated energy-active elements. The aim is to fill the knowledge gaps by providing a comprehensive framework that includes the development, research, design, and implementation of combined energy systems for buildings. The design of energy systems will be developed in BIM. An important result of this research is the development of a technological process for the implementation of a contact insulation system with integrated ATP in modular and panel buildings with a lightweight envelope. Full article

This paper explores the optimal configuration strategies for building-integrated photovoltaic (BIPV) systems in response to the low-carbon transformation needs of semi-outdoor substations, aiming to reconcile the contradiction between photovoltaic (PV) power generation efficiency and indoor environmental control in industrial buildings. Taking a 220 kV semi-outdoor substation of the China Southern Power Grid as a case study, a building energy consumption–PV power generation coupling model was established using EnergyPlus software. The impacts of three PV wall constructions and different building orientations on a transformer room and an air-conditioned living space were analyzed. The results show the EPS-filled PV structure offers superior passive thermal performance and cooling energy savings, making it more suitable for substation applications with high thermal loads. Building orientation plays a decisive role in the net energy performance, with an east–west alignment significantly enhancing the PV module’s output and energy efficiency due to better solar exposure. Based on current component costs, electricity prices, and subsidies, the BIPV system demonstrates a moderate annual return, though the relatively long payback period presents a challenge for widespread adoption. East–west orientations offer better returns due to their higher solar exposure. It is recommended to adopt east–west layouts in EPS-filled PV construction to optimize both energy performance and economic performance, while further shortening the payback period through technical and policy support. This study provides an optimized design path for industrial BIPV module integration and aids power infrastructure’s low-carbon shift. Full article

Building-integrated photovoltaics (BIPV) requires tools that improve and facilitate simulating and predicting the system’s output energy. The efficiency of a photovoltaic (PV) system can be determined by the performance ratio (PR), which relates the actual system’s output energy to the theoretical output according to the installed power and the solar irradiation, thus accounting for the power losses the PV system undergoes. Among the different parameters affecting PR, module temperature and the angle of incidence of irradiance are the most dependent on the BIPV application due to the varied module positioning. This paper assesses the suitability of several BIPV temperature models and determines the angular losses for any possible module positioning. The proposed methodology is easy to replicate and results in polar heatmap graphs to estimate PR at the desired location as a function of the tilt and azimuth angles of the modules. The calculations require irradiance, ambient temperature, and wind speed data, which can easily be obtained worldwide. Dynamic sky conditions are addressed through filters that smooth out quickly changing input data to avoid high and low peaks. The developed graphs are helpful in the decision-making process for BIPV designs by allowing the designer to estimate the expected PR of the BIPV system for any possible position of the modules on the building envelope, reducing the effect of uncertainties and resulting in more accurate and better predictions of the system’s output energy. The method applied to a BIPV façade in Madrid showed a deviation of less than 3% between the estimated and monitored PRs; the PR values ranged between 0.74 and 0.82, depending on the BIPV application and module position. Full article

Rising temperatures are intensifying residential cooling demands in hot–arid regions, with national building codes playing a pivotal role in mitigating these effects. This study evaluates the energy performance of two high-density residential buildings, Noor City in Cairo and Banan City in Riyadh, using DesignBuilder version 7.0.2.006 simulations for 2023, 2050, and 2080 under RCP 4.5 projections, followed by comparative and code-swapping analysis that assessed the role of envelope design parameters. All parameters were constant, except for those dictated by each country’s code. Results show that under future climate conditions, cooling loads in the uninsulated Noor City rise by 69% by 2080, compared to a 32% increase in Banan City. A code-swapping analysis confirmed the regulatory impact; applying the Saudi envelope to Noor City reduced annual energy use by over 40%, while using the Egyptian code in Banan City increased it by more than 50%. Solar exposure analysis further revealed that Noor City’s unshaded façades contribute to elevated thermal loads. Additionally, a 20.48 kWp rooftop photovoltaic system offsets 32:35% of annual energy consumption in both cases. While operational benefits are evident, no full life cycle cost (LCC) analysis was conducted; future studies should address economic feasibility to guide code adaptation in lower-income contexts. Full article

With the intensification of global climate change, buildings in hot climate zones face increasing challenges related to high energy consumption and thermal comfort. Building integrated photovoltaic (BIPV) façades, which combine power generation and energy saving potential, require further optimization in their climate-adaptive design. Most existing studies primarily focus on the photoelectric conversion efficiency of PV modules, yet there is a lack of systematic analysis of the coupled effects of temperature, humidity, and solar radiation intensity on PV performance. Moreover, the current literature rarely addresses the regional material degradation patterns, integrated cooling solutions, or intelligent control systems suitable for hot and humid climates. There is also a lack of practical, climate specific design guidelines that connect theoretical technologies with real world applications. This paper systematically reviews BIPV façade design strategies following a climate zoning framework, summarizing research progress from 2019 to 2025 in the areas of material innovation, thermal management, light regulation strategies, and parametric design. A climate responsive strategy is proposed to address the distinct challenges of humid hot and dry hot climates. Finally, this study discusses the barriers and challenges of BIPV system applications in hot climates and highlights future research directions. Unlike previous reviews, this paper offers a multi-dimensional synthesis that integrates climatic classification, material suitability, passive and active cooling strategies, and intelligent optimization technologies. It further provides regionally differentiated recommendations for façade design and outlines a unified framework to guide future research and practical deployment of BIPV systems in hot climates. Full article

The growing imperative for sustainable building retrofits has spurred significant interest in advanced photovoltaic (PV) solutions. This study evaluates the feasibility and competitiveness of incorporating CIGS thin-film photovoltaic (PV) modules into retrofit projects for aging buildings. By combining qualitative analyses of market and environmental factors with a quantitative multi-criteria index model, this research assesses CIGS performance across five critical dimensions: aesthetic, economic, safety, energy saving, and innovation. The weights assigned to each criterion were determined through expert evaluations derived from structured focus group discussions. The results demonstrate that CIGS exhibits substantial strengths in aesthetic, economic, safety, energy saving, and innovation while maintaining reasonable economic feasibility. The quantitative assessment demonstrated that CIGS thin-film solar cells received the highest overall score (88.92), surpassing silicon-based photovoltaics (86.03), window retrofitting (88.83), and facade cladding (82.21) in all five key metrics of aesthetics, economic feasibility, safety, energy efficiency, and innovation. The findings indicate that CIGS technology exhibits not only exceptional visual adaptability but also attains balanced performance with regard to environmental and structural metrics. This renders it a highly competitive and comprehensive solution for sustainable building retrofits. Full article

Currently, urban development has entered the stage of renewal and transformation. Energy transition is an important trend for sustainable urban development, and the assessment of solar energy potential in old residential areas in cold regions is of great significance. This study selects 47 old residential communities in Jinan, a cold region of China, as case samples. Using clustering algorithms based on spatial form characteristic parameters, the study divides the samples into five categories. The study then uses the Ladybug tool to simulate the distribution and total solar energy utilization potential of buildings in the five categories and analyzes the correlation between eight spatial form parameters and building solar energy potential. A linear regression model is established, and strategies for the application of BIPV in community buildings are proposed. The study finds that factors such as plot ratio, building density, open space ratio, volume-to-surface ratio, and form coefficient have a significant impact on the solar energy potential of residential communities; the p-values are −0.785, −0.783, 0.783, −0.761, and 0.724, respectively. Among these, building density (BD) is the most crucial factor affecting the solar energy potential of building facades. Increasing by one unit can reduce the solar energy utilization potential by 28.00 kWh/m²/y. At the same time, installing photovoltaic panels on old residential buildings in cold regions can reduce building carbon emissions by approximately 48%. The research findings not only provide methodological references for photovoltaic technology application at varying neighborhood scales in urban settings but also offer specific guidance for low-carbon retrofitting of aging urban communities, thereby facilitating progress in urban carbon emission reduction. Full article

The integration of photovoltaic (PV) systems in buildings is crucial for reducing reliance on conventional energy sources while promoting sustainability. This study evaluates and compares three energy generation systems: rooftop PV, building-integrated photovoltaics (BIPV), and a hybrid combination of both. The analysis covers energy production, economic feasibility through the levelized cost of electricity (LCOE), and environmental impact by assessing unreleased carbon dioxide (UCD). A residential building in Kerman, Iran, serves as the case study. The results indicate that rooftop PV exhibits the lowest LCOE at USD 0.023/kWh, while BIPV has a higher LCOE of USD 0.077/kWh due to installation complexities. The hybrid system, combining both technologies, achieves a balance with an LCOE of USD 0.05/kWh while maximizing energy generation at 16.2 MWh annually. Additionally, the hybrid system reduces CO₂ emissions by 9.7 tons per year, surpassing the standalone rooftop PV (5.0 tons) and BIPV (4.7 tons). The findings highlight the synergistic benefits of integrating both PV systems, ensuring higher self-sufficiency and enhanced environmental impact. This research underscores the necessity of comprehensive urban energy planning to optimize renewable energy utilization and accelerate the transition toward zero-energy buildings. Full article

The current climate emergency makes it imperative to take action to halt the irreversible destruction of the planet, with the renovation of existing buildings playing a crucial role. In Europe, particularly in Spain, energy efficiency improvements in existing buildings are undertaken in only a small fraction of cases. This gap presents a valuable opportunity to implement measures that encourage such interventions. To enhance energy production and tackle this issue from a distributed energy perspective, building-integrated photovoltaic (BIPV) systems emerge as a key solution. In this context, the primary objective of this research is to enhance the visibility and promote the adoption of BIPV systems in building energy retrofitting through the development of a standardised action framework for their installation across distinct typological clusters. To achieve this objective, a comprehensive and systematic analysis was undertaken to construct a classification that most accurately and exhaustively represents the Spanish building stock. The analysis resulted in the identification of 15 typological clusters, which, based on shared formal attributes, were consolidated into 3 principal clusters. For each of these three primary groups, a tailored action guide for BIPV system implementation was developed, addressing their specific characteristics and highlighting the critical factors to be considered in each case. To illustrate the practical application of the proposed framework, a representative case study was selected and subjected to an in-depth analysis, resulting in a detailed proposal for BIPV system installations on both the façade and the roof. In this regard, this research develops an initial procedural framework that comprehensively represents diverse building typologies, providing a structured protocol for the integration of BIPV systems within the context of energy retrofit interventions. Full article

Improving solar availability in urban blocks is vital to promoting energy conservation and emissions reduction. However, there are very few studies on the impact of block morphology on solar energy availability in high-density cities based on the particularities of climate and solar energy resources in severe cold regions at higher latitudes. This study took 434 block models generated through seven orientation conditions of 62 residential blocks in Harbin, China, as its research object. Through numerical simulations and statistical analysis, it revealed the quantitative relationship between block morphology and the availability of active photovoltaic and solar thermal collector technologies and passive thermal heating technologies. The results show that active solar technology has the highest availability in multi-story enclosed residential blocks, and passive thermal heating has the highest availability in the multi-high-level mixed-row type. The south façade of the building has the greatest active and passive solar availability. The overall active solar availability of the residential block is significantly negatively correlated with the mean building height, floor area ratio, and volume area ratio; it is significantly positively correlated with site coverage and the standard deviation of the building height. Controlling the block’s orientation between 15° south by west and 15° south by east can increase the active solar availability of the façade. This study provides a reference and evaluation basis for the sustainable planning and design of high-density cities in severely cold regions. Full article

This paper provides a methodology for improving the modelling and design of BIPV façades through in-depth solar irradiation calculations using free and open-source software, mainly GIS, in addition to free data, such as LiDAR, cadastres and meteorological databases. The objective is to help BIPV design with a universal and easy-to-replicate procedure. The methodology is validated with the case study of Building 42 in the CIEMAT campus in Madrid, which was renovated in 2017 to integrate photovoltaic arrays in the east, south and west façades, with monitoring data of the main electrical and meteorological conditions. The main novelty is the development of a methodology where LiDAR data are combined with building vector information to create an enhanced high-definition DSM, which is used to develop precise yearly, monthly and daily façade irradiation estimations. The simulation takes into account terrain elevation and surrounding buildings and can optionally include existing vegetation. Gridded heatmap layouts for each façade area are provided at a spatial resolution of 1 metre, which can translate to PV potential. This methodology can contribute to the decision-making process for the implementation of BIPV in building façades by aiding in the selection of the areas that are more suitable for PV generation. Full article

Rising global energy demand, particularly in the building sector, has catalyzed a shift toward sustainable building practices. Buildings are now being redefined from mere energy consumers to potential energy providers, with building façades offering extensive areas for solar installations. This paper reviews recent advances in Wall-Integrated Solar Energy (WISE) systems that produce heat and electricity. A detailed comparison of their structures and performance is provided for various WISE systems, including building-integrated photovoltaic/thermal (BIPV/T) systems, attached sunspaces, Trombe walls, solar thermal collectors (STCs), PV–Trombe, Bio–PV, etc. The goal of this review is to understand the capacity of these technologies to produce energy via walls. The review concludes with key findings and future recommendations, aiming to guide the sustainable evolution of the building industry. Data from the literature suggest that building walls can be a promising energy source with the appropriate integration of solar energy. Full article