Enhancing South-Facing Office Environments at 51° Latitude: Optimizing Shading, PV Performance, and Acoustics with Sloped Horizontal Fins

Abstract

This study investigates the effectiveness of sloped horizontal shading fins in enhancing visual comfort, electricity generation, and acoustic attenuation in a south-facing office room in Wrocław, Poland (51° latitude). A simulation-based approach combined Radiance daylight simulations, PV energy modeling, and graphical acoustic analysis. Four fin configurations were tested to identify the optimal design. The results indicate that Variant 3, featuring two 1 m wide fins inclined at 45°, achieved the best overall performance, increasing UDI_{300–3000/168} from 53.1% to 95.8%, reducing DGP from 50% to 27%, and enabling an estimated annual electricity production of 4.67 MWh. Additionally, applying sound-absorbing material on the shaded side of the fins significantly reduced reflective acoustic wave bounces, significantly reducing façade-exposed noise. This multifunctional solution demonstrates a practical and scalable strategy for improving office environmental quality in temperate climates, contributing to energy efficiency, acoustic comfort, and visual well being.

1. Introduction

The building sector is one of the most significant contributors to global carbon emissions, accounting for approximately 40% of total emissions and representing a substantial threat to both the environment and human health [1]. In light of global climate goals and increasing environmental concerns, improving the energy performance of buildings has become a priority. This includes reducing their energy consumption and enabling buildings to act as energy producers. Such strategies enhance energy self-sufficiency and resilience, contributing to the broader transition toward a low-carbon economy. However, energy-related improvements must be carefully balanced with indoor environmental quality (IEQ), as research shows that physical parameters such as visual comfort, air quality, lighting, and acoustics significantly influence occupant satisfaction and well being [2].

Efforts to decarbonize the built environment align with several United Nations Sustainable Development Goals (SDGs), particularly Goal 7 (Affordable and Clean Energy), Goal 11 (Sustainable Cities and Communities), and Goal 13 (Climate Action) [3]. Achieving these goals requires the integration of sustainable technologies and design strategies that reduce reliance on external energy sources while enhancing the quality of urban life.

Building overheating is a critical challenge that has emerged in recent years, worsened by climate change. In this context, external shading devices are essential for enhancing indoor quality and visual comfort while reducing the demand for air conditioning. Moreover, in densely built urban environments, these elements can serve a dual purpose by protecting against noise pollution, which is increasingly recognized as impacting human health and productivity.

In addition to their shading and acoustic benefits, light-blocking façade elements can be adapted to support energy generation technologies. For example, they can serve as mounting platforms for photovoltaic (PV) panels, contributing to the production of clean electricity. This has led to growing interest in building-integrated photovoltaics (BIPVs), which are often installed on façades in densely built-up cities with limited roof space.

However, this multifunctionality creates competition for façade space. As the demand for renewable energy solutions grows, BIPV or BIPV/T systems are often prioritized over other architectural components. This competition highlights the need for integrated design strategies that combine multiple functions, such as shading, acoustic protection, and electricity generation, into a single architectural element. Addressing this challenge is central to the development of innovative, sustainable building technologies and is the focus of this study.

Research Focus and Justification

In the presented article, the shading system of an office room located in Poland (51° N latitude) is optimized based on three essential factors: visual comfort, which relates to the quantity and quality of natural light entering the room; acoustic comfort, which refers to the indoor sound environment, including noise levels and reverberation time; and electricity generation, which concerns the amount and efficiency of power produced by the PV panels mounted on the shading fins. This study aims to develop and evaluate a multifunctional shading solution that simultaneously enhances indoor environmental quality and supports renewable energy generation in a Central European climatic context.

The optimization process utilizes a multi-objective optimization algorithm that accounts for the trade-offs and synergies among these factors to identify the optimal design and configuration of the shading system.

Applying a shading system made up of sloped horizontal fins results in acoustic wave reverberation, which is not present with an uncovered façade. Acoustic energy striking a building envelope travels into rooms (offices, workplaces) through windows, window frames, and mounting gaps. Additional reverberation amplifies this undesirable effect, increasing internal background noise in a workplace. The article offers a solution for reducing both reverberation and direct noise penetration into office interiors, backed by graphical and computational analysis.

Shading devices have become increasingly essential components of sustainable building design, particularly in temperate climates, where buildings must adapt to seasonal variations in solar exposure, temperature, and daylight availability. The multifunctionality of shading systems—facilitating enhanced visual comfort, glare control, and even acoustic mitigation—renders them central to current efforts to improve indoor environmental quality and reduce energy consumption.

Recent research underscores the impact of well-designed shading devices on thermal and visual comfort. For instance, Hou and Luo [4] demonstrated through a parametric case study in a temperate continental climate (NC, USA) that optimized shading devices can significantly reduce solar gains while improving indoor radiant temperatures throughout the year. These findings support the potential of shading to deliver stable conditions without compromising daylight availability. Similarly, Evola, Gullo, and Marletta [5] analyzed a range of shading solutions applied to an existing office building in Southern Italy and found that external shading effectively mitigated both overheating and glare while maintaining sufficient levels of natural light indoors.

Although it is commonly assumed that northern latitudes experience harsher climates with limited solar exposure, recent findings challenge this notion. For example, Czachura [6], in a study conducted in Sweden—a country located further north than Poland—demonstrated that external shading devices remain fully justified, even in cold climates. The study introduced new indices to evaluate the combined daylight and energy performance of shaded buildings, and the results emphasized the dual benefits of shading systems in reducing glare and cooling demand, particularly in cold yet sunny environments. Likewise, Cellai et al. [7] assessed shading configurations across various European locations—including Berlin, Milan, Florence, and Athens—measuring visual and acoustic impacts. Their study emphasized the necessity of climate-responsive and functionally adaptive shading systems to optimize comfort in diverse urban environments.

Despite these advancements, the simultaneous optimization of visual, energy, and acoustic comfort remains underexplored, particularly regarding façade-integrated shading systems in office buildings situated in temperate zones. This study addresses this gap by developing and testing a multifunctional shading system aimed at balancing these competing performance objectives. In doing so, it contributes to the growing body of research that promotes integrated, climate-sensitive design strategies within contemporary architecture.

2. State of the Art

The authors conducted a systematic literature review on daylight management, electricity production, and acoustic analysis. The data for the literature review were sourced from international scientific databases, including Web of Science (WoS) and Scopus, with the last search conducted on 15 January 2025. The authors examined the titles and abstracts of similar studies to identify candidate search terms (“keywords”). The search strategy for all databases included papers with the keywords “daylight”, “PV electricity production”, and “acoustic analysis”.

The scientific method outlined in the paper includes the simulation of shading elements, and references from these simulations are also included. The study selection process was multistage. Screening titles and abstracts enabled the identification of potential studies for inclusion. It became evident that “daylight” and “PV electricity production” have been subjects of numerous studies in building engineering over the past 20 years. The studies included in the state of the art are presented in their respective sub-chapters.

2.1. Sources on Daylight Analysis

Given the extensive body of research on daylighting issues, the analysis of daylighting literature has been limited to relatively recent studies focusing on horizontal shading elements such as fins, ribs, and louvers.

Sharma and Kaushik investigated the effectiveness of both vertical and horizontal louvers in enhancing visual comfort. Their study highlighted the importance of optimal louver configurations for daylighting and glare control [8]. Mangkuto et al. focused on horizontal louvers in tropical climates to meet LEED v4.1 standards, emphasizing optimal slat configurations for energy efficiency and daylight metrics [9]. Catto, Lucchino, and Goia explored horizontal louvers in double-skin façades, contributing to control strategies for optimizing louver performance in various architectural contexts [10]. Double-skin façades consist of two layers of glazing separated by a ventilated air cavity, which improves insulation, enhances natural ventilation, and contributes to better acoustic and thermal performance. Shading devices can be installed within this cavity, protecting them from harmful external conditions. Hassooni and Kamoona studied a horizontal louver system in a hospital in Najaf, Iraq, demonstrating its effectiveness in reducing radiation exposure [11]. Shen and Han evaluated two modular shading systems, a conventional horizontal louver and a deformable triangular element, for daylighting and glare control, showing the potential of modular strategies for kinetic façades [12]. De Bem et al. presented a low-cost responsive louver system tested in a bioclimatic building chamber, highlighting its effectiveness in improving thermal and illuminance management [13]. Kim and Han at Chonnam National University analyzed advanced horizontal louvers made of electrochromic modules, which adjust their transmittance to meet LEED v4.1 daylight criteria [14]. Norouziasas et al. evaluated the ISO/DIS 52016-3 standard for adaptive façades, finding that fixed horizontal shading performed better than dynamic Venetian blinds controlled by the standard algorithm [15]. In 2024, the co-author of the presented study published an article on vertical kinetic shading systems (KSSs), showing quantitative efficiency but falling short on qualitative metrics [16].

Motion-based horizontal kinetic shading systems utilizing shape memory and bi-stable flexible materials have also received attention. Naeem et al. demonstrated the potential of shape-memory alloy (Nitinol) springs in horizontal louvers to enhance thermal comfort and reduce energy consumption [17]. Vazquez and Duarte investigated bi-stable flexible materials actuated by a shape-memory alloy (SMA) for optimizing flap positions in bi-stable KSSs, providing innovative solutions for adaptive building envelopes [18]. For a summary, see

Table 1. Summary of the literature review on daylight analysis.

Author	Year	Methodology	Main Focus	Research Gap
Sharma and Kaushik [8]	2023	simulation	evaluation of vertical and horizontal louvers for improving visual comfort.	lack of experimental data.
Mangkuto et al. [9]	2022	simulation	analysis of horizontal louver systems in tropical climates to comply with LEED v4.1 standards.	static shading systems meet LEED requirements only for south and north façades in tropical climates.
Catto Lucchino and Goia [10]	2023	simulation	horizontal louver systems in double-skin façades.	existing controls are limited to simpler rule-based methods.
Hassooni and Kamoona [11]	2023	simulation	investigating horizontal louver systems in a hospital setting in Najaf, Iraq.	reliance on simulations and controlled laboratory environments.
Shen and Han [12]	2022	simulation	evaluation of modular horizontal façade systems, including conventional and deformable louver systems.	limited experimental validation in real-world scenarios.
de Bem et al. [13]	2024	simulation/experiment	development and testing of a low-cost responsive shading system prototype with horizontal louvers.	need to address the longevity and robustness of mechanical components.
Kim and Han [14]	2022	simulation	horizontal electrochromic louvers to meet daylight and energy performance standards.	analysis is restricted to equinox times without comprehensive daily routine analysis.
Norouziasas et al. [15]	2023	simulation/experiment	dynamic horizontal louver shading systems to meet energy performance standards using ISO 52016-3 control strategies.	need for in-depth sensitivity analysis of control strategies and implementing ISO 52016-3 strategies for other adaptive façades.
Brzezicki [16]	2024	simulation/experiment	analysis of vertical fin shading systems for daylight comfort performance.	temporally limited experimental validation and lack of analysis on the cost effectiveness of static versus kinetic shading systems.
Naeem et al. [17]	2024	simulation/experiment	study reducing cooling loads using shape-memory alloy (Nitinol) springs in horizontal shading louvers.	lack of studies on the scalability of smart materials, like Nitinol. insufficient data on long-term performance and durability.
Vazquez and Duarte [18]	2022	simulation/experiment	experimental research on flexible materials with two stable states activated by shape-memory alloys (SMAs). control strategies to optimize the positions of flaps in bi-stable kinetic façade systems.	focused on daylight performance, omitting metrics such as glare.

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2.2. Sources on BIPV

The idea of building-integrated photovoltaic/thermal (BIPV/T) systems emerged in the early 1990s. Nowadays, this concept is even more appealing due to its potential to support the design of net-zero energy buildings by utilizing solar energy for integrated electricity and hot water production. In modern urban environments, most buildings are high-rises with limited space for PV installation; therefore, the concept of façades with BIPV systems offers an appropriate alternative solution.

Chatzipanagi et al. presented the results of a demonstrative building-integrated photovoltaic (BIPV) installation in Lugano, where five BIPV modules were investigated under various integrations with existing systems in multiple variants of PV panel inclinations and technologies [19]. Virtuani and Strepparava tested the usefulness of a model describing the daily performance ratio of amorphous (a-Si) and crystalline silicon (c-Si) PV panels for a BIPV installation located at Supsi [20]. Ravyts et al. focused on the efficiency of BIPV systems, considering the conversion losses in the converters and cabling at the voltage level, depending on the solar cell technology [21]. Li and Ma presented a method for estimating the performance of a real solar cell after colorization, emphasizing that the façade is a decorative element of the building. Their study demonstrates the design criteria and evaluation method for the practical implementation of PV panels with high visual perceptibility [22].

Lefevre et al. presented a numerical approach to precompute static configurations of PV panels, considering shading obstacles, such as chimneys or tree shade, and identifying the characteristic positions that consistently yielded higher electricity production [23]. Vulkan et al. conducted 3D modeling of the shadows cast by buildings. The algorithm proposed by the authors can model the shadows cast on vertical or horizontal surfaces, given a database of obstacles representing buildings in the form of extruded polygons and the sun’s position at any desired time interval. The methodology’s usefulness is demonstrated in a case study neighborhood in Rishon LeZion, Israel, with diverse building typologies [24]. Klugmann-Radziemska and Rudnicka presented the experimental setup of a BIPV system located in Poland. The authors measured monthly irradiance and electricity generated by the PV installation, comparing them to data obtained from the PV-GIS system. The comprehensive analysis concluded that the partial soft shading from the nearby park decreased energy yield for the tested BIPV installation [25].

In dense urban areas, the optimal configuration of a BIPV system may not be available, so Chen et al. demonstrated that a wide range of photovoltaic installation angles causes negligible annual energy losses [26]. Barbón et al. also considered the energy losses caused by deviations from the tilt angle and the orientation of the PV installation concerning the optimal position [27]. The authors showed that non-ideal tilt and azimuth angles can lead to acceptable levels of electricity production, proving that a photovoltaic system installed in a south orientation with deviations of up to 10° in relation to the optimum tilt angle has minimal influence on energy losses. Ramtin et al. presented a numerical approach to enhance the efficiency of the BIPV/T thermoelectric system. They investigated the impact of irradiance, wind speed, and inlet air temperature on electrical and thermal exergy efficiency. The studied system was optimized using a combined optimization method based on artificial intelligence and conventional optimization methods, allowing the results to be evaluated and applied in various geographical locations [28], as shown in

Table 2. Summary of the literature review on BIPV analysis.

Author	Year	Methodology	Main Focus	Research Gap
subject: BIPV installation for different inclinations and technologies of PV modules
Chatzipanagi et al. [19]	2016	experiment	results from the demonstrative BIPV installation	the early stage of research
Virtuani and Strepparava [20]	2017	simulation	modeling of the performance of different types of PV panels for BIPV installation	geographical limitation
Ravyts et al. [21]	2020	review paper	review paper on the impact of PV technology on the efficiency of façade BIPV systems	lack of experimental data
Li and Ma [22]	2022	theoretical analysis	theoretical analysis of efficiency limitation and design criteria for PV installation	lack of experimental data
subject: influence of urban solar and thermal conditions on the electricity production of PV installations mountedon the façade of the building
Lefevre et al. [23]	2017	theoretical analysis	predetermined static configuration of PV panels with a partial shading effect	lack of experimental data
Vulkan et al. [24]	2018	simulation	PV installation in residential buildings in dense urban areas	lack of experimental data
Klugmann-Radziemska and Rudnicka [25]	2020	simulation, experiment	small-scale BIPV systems for domestic use	geographical limitation
subject: optimal positioning of the PV panels
Chen et al. [26]	2020	review paper	optimal positioning of the photovoltaic systems	geographical limitation
Barbón et al. [27]	2022	simulation	influence of the non-ideal position of the PV systems on electricity production for urban application	geographical limitation lack of experimental data
Ramtin et al. [28]	2024	theoretical analysis	artificial intelligent-based techno–economic–exergetic optimization	the early stage of research lack of experimental data

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2.3. Sources on Acoustic Attenuation

High technological development is accompanied by pollution from toxins, chemicals, and noise [29]. A 2017 ranking by Mimi Hearing Technologies GmbH showed that cities like Barcelona and Paris are among the ten noisiest places in the world [30]. The European Environmental Agency seeks all possible noise reduction means, including proper road finishing, quiet tires, electric cars, encouraging walking and cycling, and zoning peaceful areas, particularly green spaces [31]. Therefore, even small contributions matter.

To positively impact the health of building users, scientists study façade design in detail, examining various aspects, particularly user comfort, as explored by Shum and Zhong [32] and Vandenbogaerde et al. [33]. The Böke team [34] analyzed a range of fin-based shading systems, including one that closes when detecting noise pollution outside the building. The research groups led by Balasbaneh et al. [35] and Li et al. [36] focused on windows to prevent noise propagation inside buildings. Hence, façades that absorb sound perform better in urban noise reduction than those that reflect it. Kirmm et al. conducted various tests on façade-fixed blinds in multiple positions and created a series of 1:10 scale models to simulate noisy urban environments. Kirmm proved that “a structured surface can reduce environmental noise by around 3 dB, according to tests on models on a scale of 1:50 and 1:100” [37,38]. Busa et al. [39] tested building balconies, overhangs, and other similar structures in combination with sound-absorbing cladding, yielding promising results, particularly for balcony ceilings. Zuccherini and the team [40] conducted a promising experimental study on a four-story office test building. The researchers used small-scale shading louvers modified with a 7 mm thick polyurethane conglomerate as the absorbing material. Despite the fin areas having highly limited surfaces, the team achieved promising results. “This experimental investigation demonstrates the possibility of efficiently using sound absorbing shading devices to reduce average SPL [Sound Pressure Level—own explanation] over building façades” [40]. Thus, we assume that investigating the acoustic absorbance of the shaded side of the panels is worthwhile [40], as shown in

Table 3. Summary of the literature review on acoustic attenuation.

Author	Year	Methodology	Main Focus	Research Gap
Busa et al. [39]	2010	simulation and experiment on scaled models	noise reduction connected to façade geometry and material solutions, balconies, and sound-absorbing materials.	lack of studies on fins and shading systems regarding noise reduction.
Freire and Gomes [29]	2013	review paper and comparative study	general study showing noise pollution, time lasting influence of ambient noise on the population of Lisbon on the high and very high level.	the article focuses on diagnosing the problem, omitting possible solutions, for example, with the use of urban noise absorbers.
Zuccherini et al. [40]	2015	experiment	noise reduction connected to standard shading fins and fins with sound-absorbing properties.	investigation considers standard elements of small width; no information about blinds with large widths and the possibilities of energy production.
Krimm et al. [37]	2017	experiment on scaled models	noise increase connected to façades, mutual influence of façade geometry and noise levels, acoustics, soundscape, and design parameter.	missing: mutual influence of façade materials and noise levels (indicated in conclusions for future research).
Balasbaneh et al. [35]	2020	simulation and experiment	widows in noise transmittance, traffic noise, rooms requiring quiet sound background, and LCA.	considers windows solemnly.
Böke et al. [34]	2020	experiment	horizontal fins in the automated shading system, user control, wireless control, and building automation.	lack of addressing the sound wave reverberation in the horizontal fins system.
Li et al. [36]	2020	experiment	widows in noise transmittance, traffic noise, building façade, and traffic noise transmission loss.	considers windows solemnly.
EEA [31]	2020	review and interview	threats to human health from noise exposure, with a variety of possible solutions.	general overview of the problem and lack of solutions using building façades for noise absorption.
Shum and Zhong [32]	2023	review paper and simulation	shading system, user comfort, energy saving, and sustainability.	the article addresses a number of users’ comfort issues yet omits acoustics.
Vandenbogaerde et al. [33]	2023	review paper	building automation, systems, ventilation, blinds, lighting, shading, and building management.	missing: noise in terms of building control and management.

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3. Paper Objectives

The presented study aims to evaluate the effectiveness of static sloped horizontal fins (i.e., horizontal shading elements angled upwards at 45° relative to the window) through a multi-criteria analysis of visual comfort, electricity production, and acoustic attenuation in a south-facing office room with an area of 72 m². This study employs computer simulations for daylight and electricity production, along with graphical diagrams for sound attenuation. All calculations were conducted for a case study in Wroclaw, Poland (51° north latitude).

The effectiveness of the applied shading system was verified against the following criteria:

• Visual comfort. Visual comfort was evaluated using the Useful Daylight Illuminance (UDI) metric, which is the most effective as it excludes “over-illumination” hours. This is crucial for a south-facing façade. The Daylight Glare Probability (DGP) for the analyzed scenarios was also calculated.
• Electricity generation is the amount of electricity generated by PV panels covering the horizontal shading fins, which slope at a 45 ° angle.
• Noise attenuation. In the sound propagation analysis, the authors examined a version of the horizontal fin lined with sound-absorbing material on its underside (bottom surface). The diagrams graphically verify the potential for sound reflection attenuation through horizontal shading fins.

According to the methodology presented below, the authors assumed that it is possible to determine the optimal number and position of horizontal shading fins to achieve the best outcomes in the abovementioned criteria.

4. Method

This study utilized a multistage simulation and graphical verification procedure to assess the effectiveness of static horizontal shading fins in a south-facing office room while also optimizing energy generation (PV) and noise attenuation.

Simulation and Verification Procedure

The simulation procedure was performed in three stages as follows:

• In the first stage, four variants with differently positioned horizontal shading fins were evaluated from the visual comfort perspective using computer simulation—the Radiance version 5.4a engine for daylight simulations embedded in the software Ladybug Tools 1.6.1 for Rhino ver. 7/Grasshopper. The authors focused on defining the optimum number and width of horizontal fins sloped at a 45° angle. The primary metrics used to verify visual comfort were Useful Daylight Illuminance (UDI) and Daylight Glare Probability (DGP). The optimization procedure aimed to maximize the average UDI in the 300–3000 lux range for the largest possible room area.
• In the second stage, after determining the optimal number and position of fins in the visual comfort study, the efficiency of the PV installation was calculated. The assumption was that if fixed fins provided adequate visual comfort, their upper surface could be covered by PV panels, an idea previously used by the authors in an earlier paper [41].
• In the third stage, after establishing the final geometry of the shading fins, the authors verified the acoustic attenuation potential of the façade geometry, assuming the underside (bottom surface) of the fin would be lined with different types of sound-absorbing material. This stage utilized a graphical ray tracing method of subsequent sound reflections to minimize second, third, and subsequent sound reflections.

Figure 1 provides a schematic diagram illustrating the steps of the procedure clearly and concisely, offering a visual summary of the methodology applied in this study.

5. Innovative Character of the Paper

The paper includes several innovations in studying sloped horizontal fins in office environments. The key innovations include the following:

• Multifunctional Shading Systems. These multifunctional systems address various aspects of building sustainability and urban living quality, representing a novel approach compared to traditional single-function shading systems.
• Optimal Configuration of Fins. The research identifies and optimizes the configuration of sloped horizontal fins to achieve the best balance between visual comfort and energy production, minimizing self-shading effects.
• Integration with Photovoltaic Panels. PV technology is integrated into the shading system, a forward-thinking innovation that aligns with the increasing demand for sustainable building solutions.
• Acoustic Attenuation Through Shading Systems. The paper introduces the implementation of sound-absorbing materials on the underside of the fins to minimize noise propagation into the building and utilizes graphical acoustic ray tracing—a method seldom employed in the context of shading system analysis.
• Comprehensive Simulation Approach. This study employs a rigorous simulation methodology, integrating daylight, energy production, and acoustic analysis.

While the individual components of the proposed system—such as photovoltaic panels, horizontal shading fins, and sound-absorbing materials—are not novel by themselves, the innovation presented in this study lies in their integrated application and performance-driven optimization. The research introduces a multifunctional system that simultaneously addresses visual comfort, energy generation, and acoustic attenuation within a unified design. This approach reflects a methodological and systemic innovation relevant to office buildings in temperate urban environments. Although the system has not yet been physically implemented, the design was developed and simulated in detail, using defined dimensions and boundary conditions, to ensure its feasibility for future real-world applications.

6. Room Configuration and Simulation Environment Parameters

6.1. Room and Fins’ Dimensional Parameters

The test room analyzed in this study is a 12 × 6 m office room (72 m² area, 6 m depth) with a height/clearance of 4.0 m. The test room features side glazing with full-height windows facing directly south. Due to the façade’s orientation, the authors decided to simulate anti-solar Pilkington Sun-cool™ OW 50/25 glass, which has a daylight transmittance of 0.52, as specified by Pilkington [42]. The simulated rectangular fins of varying widths are positioned 0.6 m from the façade’s surface and are sloped at an angle of 45°. The 3D model of the office room was created using Rhino v7.

In daylight, a façade without shading (no fins, n = 0) served as the reference for all subsequent simulations. Next, three different combinations of fins were analyzed and gradually optimized to achieve the best results in terms of visual comfort. It should be noted that from the early stages of the research, it became evident that the shading fin should be positioned at an angle of approximately 45° relative to the glazing surface. This angle was selected based on the typical average solar altitude during the simulation period (June–July) in Wroclaw, Poland (51°N). Solar elevation at this latitude during peak working hours is approximately 42–45°, making this angle optimal for reducing glare and direct sunlight exposure while maximizing the usable surface for PV panels.

The daylight parameters were simulated for four variants of fins as follows:

• No daylight management system;
• Single 1 m wide horizontal fin at an angle of 45°;
• Double 1 m wide horizontal fin at an angle of 45°;
• Three 0.5 m wide fins at an angle of 45°.

In the context of acoustics, for the graphical analyses, the test building is assumed to be a three-story structure with a ground floor and two additional floors featuring fins distributed according to Variants 3 and 4.

6.2. Timeframe

The daylight simulation encompasses the longest sunlight days in Wroclaw, from June 9 to July 8, spanning 21 working days during office hours (9:00 A.M. to 5:00 P.M.) and totaling 168 working hours within this defined period. This timeframe features the longest days and the strongest sun irradiation, representing a potential worst-case scenario for the assumed location. The analysis period (21 days × 8 h) was chosen to average the weather data and minimize the influence of individual overcast days on the final results.

6.3. Geographical Location

All calculations were conducted for Wrocław, Poland (located in Central Europe at 51° North latitude). The Institute of Meteorology and Water Management—National Research Institute provided the most up-to-date weather data (in *.epw format compatible with EnergyPlus from the version 1.0) as well as the Typical Meteorological Year (TMY) dataset for Wrocław [43].

6.4. Local Climate

Poland has a temperate climate with distinct seasonal variations, featuring cold winters and warm summers. These climatic conditions significantly affect both indoor thermal comfort and energy consumption in office buildings. During the winter months, maintaining thermal comfort demands substantial heating, while in summer, cooling systems may be necessary to ensure occupant well being, especially in buildings with south-facing glazed façades. Consequently, energy demand in Polish office buildings fluctuates considerably throughout the year, with increasing attention being paid to the summer season due to overall climate warming and the growing number of hours with direct solar radiation during summer months. This seasonal variability highlights the importance of designing energy-efficient buildings that sustain adequate indoor environmental quality under diverse weather conditions.

6.5. Assumptions for Daylight Simulation

The authors used Ladybug Tools 1.6.0 within the Rhino 7/Grasshopper environment, utilizing the Radiance ver. 5.4a engine for all daylight simulations. Figure 2 shows the simulation setup, and

Table 4. Materials and Radiance parameters of the room surfaces and shading fins.

	Vertical Surfaces of the Test Room	Work Plane	Ceiling	Standard Window	Shading Fin Shaded Side
Material	Gray concrete	Dark gray (RAL 7000)	Gray concrete	Transparent glass	White metal
Reflectance	0.42	0.23	0.42	0	0.28
Transmittance	0	0	0	0.52 1	0

¹ Insulating glass unit made of Pilkington Suncool™ OW 50/25.

shows the Radiance parameters of the room surfaces and shading fins.

The authors used two daylight metrics to evaluate visual comfort: (i) Useful Daylight Illuminance (UDI_{300–3000/168}) and (ii) Daylight Glare Probability (DGP).

The UDI_{300–3000/168} metric specifies the percentage of time (within a predefined time frame of 168 h) during which a given virtual sensor detects illuminance within the range of 300–3000 lux. In 2017, Boubekri and Lee published a paper titled “A Comparison of Four Daylighting Metrics in Assessing the Daylighting Performance of Three Shading Systems” [44], influencing the authors’ selection of this metric. Originally, UDI was proposed by Nabil and Mardaljevic in 2005 in the paper titled “Useful Daylight Illuminance: A New Paradigm for Assessing Daylight in Buildings” [45]. Although Nabil and Mardaljevic stated, “UDI represents the annual occurrence of daylight illuminances falling within the given range” [45].

The authors used the UDI metric to verify visual comfort over the predefined period of 168 h. Additionally, commonly available software allows for calculating UDI using real, location-specific weather data, making this metric superior to others and bringing the simulation closer to real-world conditions.

It is also important to note that there is an ongoing scientific discourse about the minimum and maximum threshold levels that should be used in the UDI metric. Suk [46] published a review of different glare discomfort thresholds, presented in tabular form below. This review convinced the authors that the thresholds of 300 and 3000 lux are optimal (see

Table 5. Different glare discomfort thresholds by various authors.

Authors	Year	Thresholds	Remarks
Sutter et al. [47]	2006	>3200 lux
Linney [48]	2008	>2740 lux
Wymelenberg and Inanici [49]	2016	>4000 lux
Mardaljevic et al. [50]	2012	>3200 lux
Wienold and Christoffersen [51]	2006	<2000 lux	Perceptible
		>6000 lux	Intolerable

).

The values of UDI_{300–3000/168} were simulated based on the illuminance (E_h) at the work plane, 0.85 m above floor level, using 288 virtual sensors (a grid of 24 × 12, approximately four sensors per m²) over a 168 h simulated time frame. The results of the UDI_{300–3000/168} simulations at the work plane level are presented as a statistical analysis of UDI_{300–3000/168} values in the paper, while the spatial false-color distribution of UDI_{300–3000/168} values is provided in the Supplementary Materials.

The statistical distribution of UDI_{300–3000/168} values for the four computed variants is presented as a box plot. Additionally, the following statistical measures are provided: (i) the average ($\overline{UDI}$), (ii) the median (${\tilde{m}}_{UDI}$), (iii) the standard deviation (σ_UDI), and (iv) the maximum value (UDI_max). These values were calculated for the final UDI_{300–3000/168} distribution. Moreover, the uniformity of useful daylight illuminance (U_UDI)was also calculated by dividing the minimal value of useful daylight illuminance (UDI_min) by the average value of useful daylight illuminance ($\overline{UDI}$). The statistical analysis allows for easy comparison of the presented variants.

The other metric used in the evaluation of daylight comfort was Daylight Glare Probability (DGP), expressed as a percentage as in Formula (1), where E_v is the vertical eye illuminance (lux); L_s is the luminance of the source (cd/m²); ω_s is the solid angle of the source; and P is the position indexed by i as follows:

$$\mathrm{DGP}=5.87·{10}^{-5}·E_v+9.18·{10}^{-2}·\log \left(1+{\displaystyle \sum }_i{\displaystyle \frac{L_{s, i}^2{\omega }_{s,i}}{E_v^{1.87}{P}_i^2}}\right)$$

(1)

Jan Wienold first defined this metric at the Fraunhofer Institute for Solar Energy Systems [51]. Generally, a higher DGP number indicates a higher probability of glare. A DGP above 35% is rated as a “perceptible, non-disturbing” glare, while a DGP above 45% is considered an “intolerable” glare, as addressed by [51].

In the presented article, the authors departed from displaying DGP (Daylight Glare Probability) image-based false-color diagrams for a specific hour and a day. Instead, utilizing the most recently added component within the Ladybug Tools 1.6.0 software (HB Imageless Annual Glare), the authors calculated the DGP value for each hour over a specified time range. This recipe uses the imageless glare method developed by N. Jones to estimate glare at each sensor that is “caused by direct views to the sun and sky” [52]. DGP values can be computed much faster than the time needed to render images for each view under every sky condition, as is typically required by traditional image-based glare calculation methods. Also, for these 168 h, the authors specified the percentage of time during which the glare value fell within the above-defined categories (see

Table 6. The analysis results of visual comfort analysis for Variants 1–4 (own elaboration).

	Analysed Variant	Variant 1	Variant 2	Variant 3	Variant 4
	short description	no shade	1 fin at 45°	2 fins at 45°	3 fins at 45°
	fin width	n.a.	1 m	1 m	0.5 m
	PV area	n.a.	12 m2	24 m2	18 m2
	schematic section
	Statistical analysis
	count	288	288	288	288
	$\overline{UDI}$ [%]	61.45	78.24	88.78	91.08
	${\tilde{m}}_{UDI}$	84.23	100.00	100.00	100.00
	Q1	14.73	65.77	86.75	90.33
	σUDI [%]	41.64	33.19	20.26	17.13
	UDImax [%]	100.00	100.00	100.00	100.00
	UUDI	0.00	0.06	0.40	0.41
UDI300-3000/168 [%]
	Glare analysis
DGP [h]	intolerable	39	0	0	0
	disturbing	53	1	0	0
	perceptible	42	49	23	24
	imperceptible	34	118	145	144

). Additionally, diagrams showing DGP values for each hour over the 21 days analyzed are provided in

Table 7. The details of the analyzed PV installation.

PV Installation Parameters	Value
The maximum power of a single PV panel, Wp	350
The total number of PV panels,	12
The total electrical power of the BIPV system, kWp	4.2
The temperature coefficient of Pmax γ, %/°C	−0.38
The panel’s efficiency under STC conditions, %	18
The geometrical dimensions of a single PV panel (H/W/D), mm	1960/991/40
The inverter’s efficiency ηinv, -	0.97
The wire’s efficiency ηwire, -	0.99

for further illustration.

6.6. Assumptions for Energy Simulation

In the presented case study, the authors analyzed the possibility of producing electricity using a PV installation consisting of monocrystalline panels [53,54]. This panel type is popular in domestic and industrial systems due to its relatively low price, high energy conversion factor, and low operating costs. The manufacturer’s product warranty is 12 years, with a power warranty of 90% and 80% of the nominal output power after 10 and 25 years, respectively. The equation describes the PV power production P_PV as follows:

$$P_{\mathrm{PV}}=P_{max}{\displaystyle \frac{GI}{G_{\mathrm{STC}}}}\left(1-{\displaystyle \frac{\gamma }{100}}\left(T_{\mathrm{NOCT}}-T_{cell}\right)\right)·{\eta }_{inv}·{\eta }_{wire}·N$$

(2)

The considered panel’s standard test conditions are G_STC = 1000 W/m², cell temperature T_STC = 25 °C, and AM1.5G. The cell temperature T_NOCT = 45 °C is measured under normal operating conditions: G_NOCT = 800 W/m², ambient temperature T_a,NOCT = 20 °C, wind speed of 1 m/s, and AM1.5G. The following equation describes the current cell temperature T_cell [55]:

$$T_{cell}=T_{a,\mathrm{DBT}}+{\displaystyle \frac{GI}{G_{\mathrm{NOCT}}}}\left(T_{\mathrm{NOCT}}-T_{a,\mathrm{NOCT}}\right)$$

(3)

The cell temperature T_cell changes with solar radiation GI, so the calculations of electricity production were performed for 1 h time intervals, applying the meteorological data collected in the Typical Meteorological Year (TMY) database for Wroclaw City, Poland [43]. The formula parameters are clearly defined in the “Nomenclature” table at the end of the article.

6.7. Assumptions for Acoustic Attenuation

The authors assumed that the back surface of the fins (turned towards the façade) can serve a sound-absorbing function. The authors investigated acoustic wave propagation from the source of the sound. Huygens’ principle suggests that when a wave propagating through air encounters a solid obstacle with a smooth surface (such as a fin), the material absorbs some of the wave’s energy. In contrast, the majority of the energy is reflected off the surface [56,57]. As the angle of incidence equals the angle of reflection [58], the authors used a graphical method to determine the number of sound waves that reach the façade and the number that bounce off.

The authors assumed the height of the linear source in the cross-section to be 30 cm from the level of the asphalt street, which is the average height of the car engine in a standard vehicle (approximately 60 cm) and the height of the tire rubbing against the road surface (approximately 0 cm). The distance of the linear source from the edge of the building was also averaged, and they assumed 200 cm for the width of the sidewalk, 10 cm for the curb width, 50 cm for the road gauge, and 100 cm for the distance from the position of the car engine in a standard vehicle. Also, the absorbing material is theoretically “perfectly” acoustic energy absorbing.

7. Results

The results of this study present a comprehensive analysis of the data collected and include the key findings. The authors have organized this chapter into several sections, each detailing specific aspects of the investigation. By systematically presenting the results, the authors aim to provide a robust foundation for the subsequent discussion and interpretation, emphasizing the significance of the findings.

7.1. Daylight Simulation

The visual comfort simulation process consisted of four consecutive phases described above in Section 6.1. First, the office room was simulated without any shading device (Variant 1). Second, a single 1 m wide fin at an angle of 45° and a height of 300 cm above the floor was introduced (Variant 2), providing evident improvement in both UDI_{300–3000/168} and DGP values but still remaining unsatisfactory. Third, to further increase UDI_{300–3000/168} and reduce DGP, an additional 1 m wide fin was introduced 100 cm above the floor (Variant 3). To verify the correctness of the previous outcome, a fourth variant (Variant 4) was simulated, featuring three 0.5 m wide fins at 100, 200, and 300 cm above the floor. This configuration slightly improved the metric values, providing visual comfort in almost all virtual sensors.

7.1.1. UDI

Variant 1. The simulation results for Variant 1, which lacks any daylight management system and glare protection, show relatively low UDI_{300–3000/168} values ($\overline{UDI}$ = 61.45%) and a very high probability of glare. There are 39 h of intolerable glare (DGP > 45%) and 53 h of disturbing glare within the 168 h test period. Near the façade, UDI_{300–3000/168} values are as low as 0%, indicating that this part of the work plane is over-illuminated for 100% of the working hours. Only the back of the room, 6 m away from the façade, which constitutes 37% of the room area, achieves visual comfort 100% of the time. The standard deviation is high, at 41.64, and the box plot shows a large spread, with outliers reaching 0% UDI.

Variant 2. Introducing a single 1 m wide horizontal fin at an angle of 45° significantly improved visual comfort. The mean $\overline{UDI}$ increased by 27.32%, from 61.45% to 78.24%. DGP analysis shows zero hours of intolerable glare. UDI_{300–3000/168} values near the façade increased to 18%, while 56% of the room’s area (162 out of 288 sensors) achieved visual comfort 100% of the time.

Variant 3. Adding a second 1 m wide horizontal fin at a height of 100 cm above the floor further improved the results, particularly near the façade, where UDI_{300–3000/168} values reached 99%. The mean $\overline{UDI}$ increased to 88.78%, the standard deviation dropped to 20.26, and 56% of the work plane was correctly illuminated for 100% of the time. All values of DGP for sensor “A” were in the “perceptible, not disturbing” and “imperceptible” range.

Variant 4. Variant 4 introduced three 0.5 m wide fins. This configuration slightly improved the mean $\overline{UDI}$ by 2.59%, from 88.78% to 91.08%, with the same DGP hourly distribution as Variant 3. Although the fins were more evenly distributed in height, their thinner profile blocked approximately the same amount of light in terms of visual comfort, as reflected by the UDI_{300–3000/168} results. A slight improvement was observed in the correctly illuminated area, with 61% of the work plane being correctly daylit for 100% of the time compared to 56% in Variant 3 (see Table 6).

The ${\tilde{m}}_{UDI}$= 100% in Variants 2 to 4 indicates that at least 144 UDI_{300–3000/168} values equaled 100%. This demonstrates that all shading strategies were effective. Even though the remaining UDI_{300–3000/168} values fell between 0 and 100, their effect on the median is negligible, as most or half of the values are clustered at the upper bound (100%).

Also, the analysis of the first quartile reinforces the conclusions from the above. For Variant 1, the 25th percentile is 14.73, meaning 25% of the values are below this, suggesting many low daylight exposure instances. In contrast, for Variant 4, the 25th percentile is 90.33, indicating that even the lower quartile has a relatively high level of daylight exposure, reflecting much better conditions overall.

7.1.2. DGP

The calculations revealed that the most significant glare risk occurs in a room without any protection against solar radiation in Variant 1. In Variant 2, the conditions improve significantly, although one of the 168 h remains affected by disturbing glare. In Variants 3 and 4, the number of hours at risk of glare decreases to zero. Throughout the entire analyzed period, the DGP values fall within the “perceptible, not disturbing” or “imperceptible” range. The exact distribution of glare values for point “A”, corresponding to sensor 131, is shown in Figure 3.

Variants 2 through 4 were also compared using other criteria to define the optimal solution. In Variant 2, the fin area that could be covered with PV panels is 12 m², while in Variant 3, the area is doubled to 24 m². Although Variant 4 performs only 1.1% better in visual comfort, the area available for PV coverage is 25% smaller than in Variant 3 (18 m² vs. 24 m²). Therefore, the authors confidently state that considering various criteria for evaluating the façade’s shading, the optimal Variant 3 provides visual comfort and maximizes the yield from electricity production.

7.2. Electricity Production

Selecting Variant 3 as the optimal solution for the case study, the authors considered fixed sloped horizontal fins that are always oriented towards the south and inclined at an angle of 45° to the façade’s surface. Each shading fin is constructed from six monocrystalline panels with standard geometrical dimensions (H/W/D) of 1960 × 991 × 40 mm. The maximum power of a single PV panel is P_max = 350 Wp. Thus, the total number of PV panels for two horizontal shading fins is N = 12. The total electrical power of the considered BIPV system is 4.2 kWp. For the considered PV panels, the temperature coefficient of P_max is equal to γ = −0.38 %/°C, and the panel’s efficiency under STC is 18%. The inverter and wire efficiencies are η_inv = 0.97 and η_wire = 0.99, respectively [54]. The details of the analyzed PV installation are presented in Table 7.

Based on the Typical Meteorological Year (TMY) database for Wrocław, Poland [43], electricity production calculations were conducted for 30 days (June 9–July 8) between 09:00 A.M. and 05:00 P.M. Meteorological data were monitored at one-hour intervals, so global irradiance (GI) and ambient temperature (T_a,DBT) were treated as fixed values during each interval. In this approach, the unit of solar irradiance (W/m²) is identical to the unit of energy (Wh/m²).

During these 30 days, the average global irradiance for 8 h was 2.92 kWh/m², while the 24 h average was 4.25 kWh/m². This indicates that the PV panels are exposed to almost 68.9% of the daily solar irradiance during office hours (09:00 A.M.–05:00 P.M.), justifying the calculation of electricity production solely for these hours. The total electricity generated by the 12 PV panels over 30 days was 369.38 kWh during the 8 h daily operation and 541.57 kWh when considering continuous 24 h performance over the same timeframe. The mean overall energy conversion efficiency was 17.6%, which aligns with the theoretical panel efficiency under standard test conditions (STCs) of 18%. The annual electricity production from the 12-panel PV installation is 4.67 MWh, a significant component of the BIPV system.

In the considered variant, the shading fins are oriented to the south and are fixed with a vertical distance of 2 m between them. The authors estimated the potential shading effect of the upper panel on the lower one, which could influence the electricity production of the lower PV panels. Calculations showed that the shading effect on the lower fin occurs only for a few days around the summer solstice (June 21st in Poland) and covers approximately 2% of the lower fin surface. On other days, the fins do not shade each other. This serves as an additional argument for choosing Variant 3 as the optimal solution in electricity production.

7.3. Acoustic Attenuation

The acoustic simulation assumes that the test room is located on the second floor of a three-story structure, facing a busy street that serves as a potential noise source. The test room features fins distributed according to Variants 3 and 4, as determined in Section 6.1. The floor height is four meters, and the finished ceiling slab measures 40 cm. The following diagrams illustrate two theoretical cases as follows:

• Case S1: The shaded side of the fin covers sound-reflective material for Variants 3 and 4, as described in Section 6.1 (Figure 4).
• Case S2: The shaded side of the fin covers sound-absorbing material for Variants 3 and 4, as described in Section 6.1 (Figure 5).

The authors considered direct sound from a linear source, such as car traffic from a road in front of the building. Previously analyzed shading fins covered with PV panels and the glazed façade are considered “obstacles” in the acoustic analysis. The reflections from obstacles up to the third level (higher sound reflections are simplified to an n-level) were graphically analyzed in a street cross-section. For clarity, each ray represents the path and direction of the analyzed sound waves and is perpendicular to the wavefront. In both case S1 and case S2, 36 acoustic waves were graphically analyzed, radiating from a linear source, represented as a point in cross-section (LS1). Below, the authors present the results of the graphical acoustic analysis for direct and reflected waves from the façade with fins in Variants 3 and 4. The drawing demonstrates the assumptions described in Section 6.7.

Since the acoustic energy hitting the façade tends to propagate into the rooms through windows, window frames, and all mounting gaps, its amount is crucial. Transparent building elements and their envelopes are always less isolating than solid structural walls, usually fitted with thermal insulation. If not present initially, air gaps appear over the years of building usage due to technical wear and tear. Therefore, the authors calculated the direct sound waves and their reflections from the fins hitting the façade for Variants 3 and 4, presented in the following juxtaposition, as shown in

Table 8. The number of direct sound waves and their bounces coming from fins hitting the façade for Variants 3 and 4—case S1—the reflective–reflective surface of fins (own elaboration).

	Case S1—the Reflective–Reflective Surface of Fins
	Direct	Bounce Number
		1st	2nd	3rd	-nth	Σb
Variant 3	18	12	17	7	2	38
Variant 4	29	9	15	3	4	31

.

The number of additional sound bounces from the fins was significant for both variants, totaling 38 and 31, respectively. In both Variants 3 and 4, in case S1, the inner background noise produced by road traffic would increase, resulting from the bounces off the surface of the fins. Reflections towards the sidewalk suggest that traffic noise would be magnified for pedestrians, which is also undesirable. Thus, the authors decided to analyze Variants 3 and 4 in case S2, where the back side of the fins is covered with “perfectly” sound-absorbing material, as shown in Figure 5.

Though this study is theoretical, it is worth looking at it from a practical angle. Acoustic absorption of a particular material is typically measured as a surface area multiplied by an absorption coefficient, which varies depending on frequency. In the article, metric sabins express the sound absorption provided by a selected surface, where one metric sabin is the absorption from a 1 m² open window [58]. Depending on density, each material has a different absorption coefficient [59,60]. The authors prepared a comparison, as shown in

Table 9. The surface acoustic absorbance per 1 m² in sabins of additionally covered fins with differentiated materials relating to the frequency (own elaboration based on [59]).

	125 Hz		250 Hz		500 Hz		1000 Hz		2000 Hz		4000 Hz
	Sabins	%	Sabins	%	Sabins	%	Sabins	%	Sabins	%	Sabins	%
Concrete	0.01	1	0.02	2	0.04	4	0.06	6	0.08	8	0.01	1
Plaster	0.01	1	0.02	2	0.02	2	0.03	3	0.04	4	0.05	5
Fiberglass board, 5 mm (thick) 1	0.18	18	0.76	76	0.99	99	0.99	99	0.99	99	0.99	99
Perforated metal—13% open. Over 50 mm (thick) fiberglass	0.25	25	0.64	64	0.99	99	0.97	97	0.88	88	0.92	92

¹ Material selected for further calculations.

, of several examples of surface sound absorbance for fins with a unit area of 1 m² in sabins. The juxtaposition shows the possibilities and range of changes in acoustic absorbance parameters depending on the type of materials used and the frequency, revealing the limitations of the practical performance (further discussed in the conclusions).

The comparison of the initial data for acoustic absorbance per 1 m² in sabins of additionally covered fins with differentiated materials shows an increase in range from 96% up to 99%—depending on frequency and material.

The conclusions present possible benefits in absorbing the traffic noise and are worth further investigation. Case S2, with sound-absorbing material on the back side of fins in Variants 3 and 4, demonstrates a significant reduction in acoustic energy around the façade and eliminates unwanted phenomena, totaling 0 in both analyzed cases. Therefore, the authors conclude that fins equipped with absorbing material on the back side will help reduce the acoustic energy reaching the building surface from linear noise sources, such as roadways. To determine which variant allows the least energy to penetrate the office interior, the authors counted the number of acoustic waves reaching the façade directly. In the analyzed case S2, the authors found no bounces off the fins, resulting in a Σ_b = 0; see

Table 10. The number of direct sound waves and their bounces coming from fins hitting the façade for Variants 3 and 4—case S2—the sound-absorbing surface of fins (own elaboration).

	Case S2—the Sound-Absorbing Surface of Fins
	Direct	Bounce Number
		1st	2nd	3rd	-nth	Σb
Variant 3	18	0	0	0	0	0
Variant 4	29	0	0	0	0	0

.

The analysis (Figure 4, Table 8) shows that fins in Variant 3 protect more of the façade surface from noise exposure, as fewer direct acoustic waves hit the façade’s surface. It was also important to investigate the surface area of the absorbing material, which is directly dependent on the surface area of the back side of the fins. A fin length of 12 m per floor was calculated (

Table 11. The surface of absorbing material depends on the surface of the back side of the fin for Variants 3 and 4 (own elaboration).

	Length [m]	Width [m]	Single Fin Surface [m2]	Number of Fins	Tot. Suf. [m2]
Variant 3	12	1	12	2	24
Variant 4	12	0.5	6	3	18

).

The analysis (Figure 5, Table 11) shows that Variant 3 provides more surface area for sound-absorbing material. Regarding the acoustics of workspaces, the conclusions from Table 8 and Table 10 indicate that Variant 3 is more suitable for further studies.

8. Discussion and Conclusions

This study investigated four configurations of sloped horizontal shading fins to determine the optimal solution for enhancing visual comfort, energy efficiency, and acoustic attenuation in an office space. Variant 3—comprising two horizontal fins, each 1 m wide and sloped at a 45° angle—was identified as the most effective option across all evaluated parameters.

8.1. Key Quantitative Findings

• Daylight performance: Variant 3 achieved a nearly optimal UDI_300–3000 of 88.78% (UDI_300–3000 increased from 53.12% to 95.75%), with 0 h of disturbing glare (DGP from 50% to 27%), compared to 144 h in Variant 1.
• Energy generation: Variant 3 enabled annual production of 4.67 MWh from 12 photovoltaic panels, representing a significant energy contribution for urban BIPV applications.
• Acoustic performance: The extended fin surface effectively covered sound-absorbing materials, reducing façade noise exposure. While standard absorbers underperform in low frequencies (125–250 Hz), this study suggests supplementing with bass traps.

8.2. Design Guidelines

• Fins should be sloped (preferably at 45°) to optimize daylight uniformity and glare reduction.
• Fins should be placed at multiple vertical levels (e.g., 100 cm, 200 cm, 300 cm above floor level) to distribute daylight evenly and support both acoustic and solar integration.
• Fin dimensions should allow dual functionality—a lower surface dedicated to acoustic absorption and an upper surface reserved for PV installation.
• Spacing must be optimized to prevent self-shading and maintain high energy production.

The results of this study support a set of practical design guidelines for enhancing office environments in temperate climates. Sloped horizontal fins can significantly improve visual comfort by reducing glare and achieving uniform daylight distribution. Simultaneously, these shading elements can serve as platforms for photovoltaic panels, contributing to on-site energy generation, and when lined with sound-absorbing material on the shaded side, they can reduce façade-related noise propagation. Based on the simulations, designers are encouraged to integrate such multifunctional fins early in the building design. The geometry—including fin width, inclination angle, and spacing from the façade—should be carefully evaluated and optimized through simulation before installation to ensure the best performance across visual, acoustic, and energy criteria.

While not analyzed in this study, using commercially available PV panels and standard absorptive materials (e.g., fiberglass boards) suggests that implementation costs would be moderate relative to the energy savings and noise comfort benefits.

8.3. Replicability

These findings are particularly relevant for office buildings situated in temperate or mixed climates with comparable solar and acoustic exposure patterns. Utilizing local climate data in simulations ensures that the results can be applied to similar urban environments where façade optimization faces restrictions due to limited installation space and strict performance requirements.

8.4. Broader Implications

The proposed solution demonstrates a multifunctional approach to façade design, integrating daylight management, renewable energy production, and noise mitigation within a single architectural element. Variant 3 contributes meaningfully to developing sustainable, high-performance workspaces by improving occupant comfort while reducing energy dependency.

In summary, this study demonstrates that implementing Variant 3—consisting of two 1 m wide sloped horizontal fins positioned at a 45° angle—offers a highly effective, multifunctional solution for improving office building performance. This configuration significantly enhances visual comfort by increasing uniform daylight distribution and reducing glare, achieving a UDI_{300–3000/168} of 95.8% and lowering DGP to 27%. It also provides a generous surface area for photovoltaic integration, enabling the annual production of approximately 4.67 MWh of clean energy while minimizing self-shading losses through optimized spacing. From an acoustic perspective, Variant 3 maximizes façade coverage with absorbent surfaces, eliminating sound wave reflections and improving the interior sound environment. Altogether, these findings confirm that when carefully designed, sloped horizontal fins can simultaneously meet daylighting, energy, and noise control goals. The proposed shading system exemplifies a holistic, scalable strategy for sustainable office design in urban settings, enhancing occupant comfort and building efficiency.

An essential advantage of the proposed sloped horizontal fin system is its potential for retrofit applications. Since the fins are designed as external, independently supported elements, they can be mounted onto existing façades without requiring significant structural alterations. This makes the solution particularly attractive for upgrading older office buildings, which often suffer from poor daylight control, excessive glare, and a lack of renewable energy integration.

By enabling visual comfort improvements, acoustic attenuation, and on-site electricity generation in a single intervention, the system offers a practical pathway for enhancing the sustainability and performance of existing building stock, aligning with broader goals of urban regeneration and energy transition.

8.5. Limitations of This Study

This study has several limitations that should be considered. Firstly, the analysis relies heavily on computer simulations for daylight, energy production, and acoustic attenuation, which may not fully capture real-world complexities. The results are specific to Wroclaw, Poland, and may vary significantly in different geographic locations with distinct climatic conditions and solar angles. The acoustic analysis primarily addresses sound-absorbing materials on the back side of the fins, without extensive exploration of other potential noise sources and interactions with various building materials. The economic feasibility and return on investment for implementing the proposed solutions were not evaluated.

Moreover, this study focused on visual and acoustic comfort, neglecting other important aspects of occupant comfort, such as thermal comfort and indoor air quality. Lastly, the research used current technology and materials; future advancements could impact the findings and recommendations. Addressing these limitations in future research can offer a more comprehensive understanding and validation of the proposed solutions. These limitations suggest several avenues for future research, as outlined below.

8.6. Future Research

The key innovation of this study lies in the integrated optimization of sloped horizontal fins that serve multiple functions: improving visual comfort, attenuating urban noise, and generating electricity through building-integrated photovoltaics. While these aspects have been explored individually in prior research, this study combines them into a single, multifunctional shading solution tailored for office environments in temperate climates. Moreover, the use of graphical acoustic ray tracing in the context of external shading analysis represents a novel methodological contribution.

Building upon the innovative integration of daylight control, energy generation, and acoustic comfort presented in this study, future research should aim to further develop adaptive and intelligent shading systems that respond dynamically to both daily and seasonal changes in solar exposure. Such systems hold the potential to redefine façade performance standards, enabling real-time optimization for comfort and energy efficiency. Furthermore, in-depth investigations into long-term durability and material resilience, including weather resistance, acoustic integrity, and maintenance cycles, will be critical for sustainable performance. Lastly, assessing the economic viability and lifecycle value of these integrated solutions will provide essential data to support their scalability and adoption in contemporary architectural practice, especially within the context of smart and climate-resilient building design.