Indoor Illumination Research Articles

Development of a camera-based device for real-time indoor illuminance distribution assessment using a deep-learning model

Real-time monitoring and assessment of indoor illuminance are crucial for maintaining environmental quality, visual comfort, and building energy efficiency. Traditional systems struggle with complex layouts, but integrating real-time monitoring with smart building management enhances comfort and sustainability. This study presents an innovative method combining a CMOS camera, data processing, and deep learning algorithms. The camera captures continuous images and extracts texture features affected by lighting. A machine learning model then predicts the illuminance distribution, generating detailed light maps in real-time. This novel sensing system, validated through experiments at the University of Skikda, provides a promising solution to improve light management by optimizing daylight use, reducing energy consumption, and enhancing visual comfort. It offers architects and facility managers a tool to integrate real-time data into building management systems for more sustainable indoor environments.

Stimuli‐Responsive Smart Glass with Switchable Unidirectional Light Source for Enhanced Privacy/Indoor Illumination

AbstractLight manipulation is in high demand in science and industry. Smart glasses enable dynamic light control for indoor illumination, privacy protection, automobiles, and displays. However, existing technologies often limit single‐functionality (simultaneous bidirectional transparency or opacity) and strongly inherent user preferences. Here, a novel class of stimuli‐responsive smart glass featuring a switchable unidirectional light source using 2,2‐dimethoxy‐2‐phenylacetophenone (DMPAP)‐doped twisted hybrid polymer network liquid crystals (TH‐PNLCs) with a linear polarizer is developed. These DMPAP‐doped TH‐PNLCs exhibit a blue‐shift in spectra under cross‐polarizer, enhanced twist angle, and increased light amplitude compared with undoped devices. When subjected to external electric stimuli and edge light, the device emits light bi‐directionally with different polarizations. As a proof of concept, placing a transmissive polarizer in front of the homogeneous alignment layer (Surface A) enables light absorption and scattering toward vertical alignment (Surface B), ensuring privacy by blocking visibility from Surface A while keeping Surface B visible. Replacing the transmissive linear polarizer with a reflective one enhances light scattering, boosting intensity from Surface B, making the device ideal for energy‐efficient indoor lighting. Featuring fast switching times and robust endurance, this stimuli‐responsive smart glass offers a pioneering solution for green buildings and automobiles with enhanced privacy and indoor illumination.

Indoor Daylighting Quality Optimization Methods of a Novel Linear Transmissive Concentrator-Photovoltaic/Daylighting System in Overcast Conditions

This study proposes a control method for improving the efficiency of natural daylighting in linear transmission-type concentrator-photovoltaic/ daylighting (LTC-PV/D) systems. The study focuses on tackling the low capacity efficiency and shading of light in LTC-PV/D systems under overcast environments. The light-harvesting performance of a proposed new dynamic trackable transmissive concentrating integrated window in an overcast environment is investigated in this study. The results indicate that, in terms of light harvesting efficiency, the percentage value of the daylight factor value of the LTC-PV/D system being more than 2% is 78.8%. Further, the maximum illuminance uniformity result reaches 0.43, which is in line with the standard of indoor illuminance demand and superior to the common results of the photovoltaic window (66.06% and 0.31), indicate a good day-lighting performance in overcast environments. For the regulation method of LTC-PV/D systems in overcast environments, the recommended control angle is 90° for using the daylight factor and uniform daylight factor indices as evaluation criteria. The trend of the indoor useful daylight illuminance is affected by different levels of outdoor diffuse radiation. For an outdoor diffuse radiation less than 280 W/m2, the optimal control angle is 90°. For outdoor diffusion radiation levels of 320, 360, and 400 W/m2, the corresponding optimal regulation angles are 55°, 35°, and 25°, respectively. This study presents a control method for the transmissive concentrating photovoltaic louver under overcast conditions, which aims to optimize and enhance the indoor natural lighting environment of buildings. The proposed method increases the maximum useful daylight illuminance by 37.3%.

Performance Study of Random Layout Light Source for Visible Light Communication System

In indoor visible light communication, a rational layout of light sources is required to ensure that multiple users at different locations in the room can obtain better communication quality and achieve uniform coverage of optical power on the receiving surface. The article investigates the performance of an indoor visible light communication system when the random layout of the Matern hardcore point process is used and compares it with the communication performance under the Poisson point process and the binomial point process. A particle swarm optimization algorithm is introduced based on the Matern hardcore point process, where the points generated under the Matern hardcore point process are used as the initial positions of the particles, and optimization adjustments are made according to the objective function to find the optimal layout. The results show that compared with the Poisson point process and the binomial point process, the use of the Matern hardcore point process to randomly lay out the LEDs makes the light intensity in the system more uniform and the numerical fluctuation of the received power is smaller. The uniformity of the indoor illumination after the combination of the Matern hardcore point process and the particle swarm optimization algorithm reaches 0.84, the deviation of the peak power is reduced by 20%, and the average signal-to-noise ratio value is 0.86, which is an increase in the average signal-to-noise ratio compared to the average signal-to-noise ratio before optimization.

Design and photothermal coupling analysis of Kresling origami-based intelligent dynamic shading system

This study investigates the design and mechanical analysis of Kresling origami structures for reconfigurable intelligent dynamic shading system aimed at enhancing energy efficiency and thermal management. A mechanical model was developed using the principle of minimum potential energy, followed by 4D printing of specimens tested under compression, showing strong alignment with theoretical predictions. The research highlights the system's intelligent ventilation capabilities, incorporating adjustable fan blade units into the Kresling structure. Shape Memory Polymer (SMP) enables intelligent folding, while Carbon Fiber Reinforced Polymer (CFRP) ensures structural stability. The photothermal coupling analysis reveals how the system autonomously adjusts the shade angle in response to environmental changes, improving indoor illumination and thermal comfort. This intelligent shading system outperforms conventional permanent solutions, reducing energy consumption and enhancing user comfort, ultimately providing innovative insights for future energy-saving technologies in buildings.

Photovoltaic windows based on ultrathin transition-metal dichalcogenides: Natural indoor illumination spectra and energy-saving potential

Semitransparent photovoltaic windows are attractive for building-integrated applications because they can regulate natural indoor illumination while generating power. In this work, we assess the potential of transition metal dichalcogenide (TMDC) semitransparent solar cells as emerging technology for this application. We model a semitransparent ultrathin photovoltaic device containing a MoS2 or WSe2 absorber and find that it can be optimized to produce a balanced absorption of the sunlight spectrum because of the unique optical properties of these materials, eliminating the common problem of the undesired coloring of the transmitted light. The device also exhibits high angular absorptance. We estimate a potential saving between 16 % (winter) and 23 % (summer) in the electricity consumption of a high-rise office building located in Madrid, Spain, by implementing TMDCs semitransparent windows with an average photopic transmission (APT) of 24 %. Notably, this is compatible with a high quality in the transmitted light: the color rendering index (CRI) of the PV windows exceeds 90 for an APT between 23 % and 65 %. These results, along with the fact that TMDCs can be deposited using low-cost, scalable methods, indicate that TMDCs hold great potential for developing color-neutral, power-generating building glazing.

Assessing visual comfort for active building enclosures: a novel simulation workflow for environmentally active top lighting cells

This study examines the impact of top lighting cells in a low-latitude city. It hypothesizes that an environmentally active control system enhances indoor illuminance without causing glare. It proposes a parametric procedure based on three simulation stages using UDI/UDIavg, Image-based, and Imageless DGP. The first stage is a simplified approach for evaluating image-based simulations considering representative dates. The second stage uses the image-based results for selecting the most contributing motion parameters through a One-way Variance-based Sensibility Analysis. The third expands the system's complexity for grid-based year-round simulations. Results indicate tilt motion as the most contributing factor for daylight control. Furthermore, the cells supplement daylight indoors, rendering a minimal increase of approximately 30% of the hours within the adequate illuminance range compared to the base case with no zenithal opening. The system ultimately achieve 100% of the hours in compliance with the selected daylight thresholds without significantly increasing glare.

Synergistic potentiation between P3HT and PTAA enables blade-coated carbon-electrode perovskite solar cells with >21% outdoor and >35% indoor efficiencies

P3HT is a promising hole-transport layer (HTL) for efficient and stable carbon electrode-based perovskite solar cells (C-PSCs). However, the reported low efficiencies of P3HT C-PSCs, resulting from the unmatched band alignment and electronically poor contact between perovskite and P3HT, is an obstacle. In this work, we propose a binary HTL system that incorporates PTAA into P3HT to address this issue, thereby achieving efficiencies of 21.3 % (0.04 cm2) and 18.8 % (1.0 cm2) under AM 1.5G illumination, and 35.2 % under indoor illumination of 1000 lx, all of which are the highest reported values for low-temperature printable C-PSCs. Experimental and theoretical results revealed that the performance improvements mainly stem from the following collaborative effects between P3HT and PTAA: 1) the introduction of PTAA increases more face-on orientations of P3HT as well as enhanced π–π stacking, forming more effective charge transport channels as molecular bridges; 2) the hole extraction barrier from perovskite to P3HT is reduced by 0.07 eV through incorporating PTAA; 3) triarylamine PTAA and other more face-on configurations can provide additional and stronger passivation sites, intensifying the defect passivation effects. Finally, unencapsulated P3HT-PTAA C-PSCs maintain ≈91 % of initial performance after maximum power point tracking for over 900 h.

Effects of near-infrared radiation in ambient lighting on cognitive performance, emotion, and heart rate variability

Although sunlight contains approximately equal amounts of near-infrared radiation (NIR) and visible light, NIR is absent from most present-day electric lighting systems and is filtered by energy-efficient windows. However, NIR is biologically active and is commonly applied in targeted photobiomodulation treatments for a range of cognitive, emotional, and physical conditions. Given the removal of NIR from indoor illumination, it is critical to understand how ambient NIR may influence psychological and physical health, and whether reduced exposure to NIR in indoor environments could because for concern. In a preregistered within-subjects double-blind experiment, acute effects of NIR and far-red wavelengths in ambient illumination on cognition, emotional state and cardiovascular health were examined in a sample of 151 university students (117 females, 34 males). During a 2-h laboratory session, participants were monitored at rest and while engaged in cognitively demanding tasks across two counterbalanced lighting conditions. Both included 3500 K white light generated by a light-emitting diode (LED) system, while one additionally included LEDs with peak wavelengths in the NIR (875 nm, 960 nm) and far-red (735 nm) spectrum. The addition of NIR and far-red to the ambient lighting showed beneficial effects on resting high-frequency heart rate variability (HF-HRV), HF-HRV responses to cognitive demand, and feelings of pleasure, but reduced performance on a visual search task. These findings reveal that the absence of NIR from architectural lighting influences humans at a psychological and physiological level, with implications for health and well-being that need to be balanced with energy-saving considerations.

Development and evaluation of a free-form-based optical antenna with enhanced channel performance

Optical receiving antennas play a pivotal role in enhancing the communication quality of visible light communication (VLC) systems. In this study, we propose an innovative optical receiving antenna based on free-form surfaces. Initially, the layout scheme for the LED array is meticulously optimized to ensure uniform indoor illumination. Subsequently, a three-piece integrated optical receiving antenna is designed using XY polynomial free-form surfaces with the primary objectives of amplifying the optical gain, augmenting the received power, and elevating the signal-to-noise ratio (SNR). To further validate the efficacy of the proposed optical receiving antenna, an indoor VLC channel model is established, and its performance is rigorously analyzed. Experimental outcomes reveal that the mean square error of indoor illumination stands at 113.3 lx, the optical gain of the free-form optical receiving antenna reaches an impressive 11.29, the semiregular field of view spans 35.2°, the average received power amounts to 6.1251 dBm, the average SNR attains 84.7054 dB, and the radius of the optical spot is a mere 1.5 mm. Consequently, the optimized free-form optical receiving antenna can guarantee high-speed and stable communication within indoor VLC systems, thereby furnishing crucial technical support for the advancement of VLC communication technology.

CGLight: An effective indoor illumination estimation method based on improved convmixer and GauGAN

Illumination consistency is a key factor for seamlessly integrating virtual objects with real scenes in augmented reality (AR) systems. High dynamic range (HDR) panoramic images are widely used to estimate scene lighting accurately. However, generating environment maps requires complex deep network architectures, which cannot operate on devices with limited memory space. To address this issue, this paper proposes CGLight, an effective illumination estimation method that predicts HDR panoramic environment maps from a single limited field-of-view (LFOV) image. We first design a CMAtten encoder to extract features from input images, which learns the spherical harmonic (SH) lighting representation with fewer model parameters. Guided by the lighting parameters, we train a generative adversarial network (GAN) to generate HDR environment maps. In addition, to enrich lighting details and reduce training time, we specifically introduce the color consistency loss and independent discriminator, considering the impact of color properties on the lighting estimation task while improving computational efficiency. Furthermore, the effectiveness of CGLight is verified by relighting virtual objects using the predicted environment maps, and the root mean square error and angular error are 0.0494 and 4.0607 in the gray diffuse sphere, respectively. Extensive experiments and analyses demonstrate that CGLight achieves a balance between indoor illumination estimation accuracy and resource efficiency, attaining higher accuracy with nearly 4 times fewer model parameters than the ViT-B16 model.

Lanthanide‐Like Contraction Enables the Fabrication of High‐Purity Selenium Films for Efficient Indoor Photovoltaics

AbstractThe lanthanide contraction involves a reduction in atomic radius among f‐block elements below the expected level. A similar contraction is observed in group‐16 elements. The atomic radius of Se (117 pm) is slightly larger than that of S (104 pm) arising from the presence of d electrons, compared to the significant increase in atomic radius from O (73 pm) to S. This lanthanide‐like contraction contributes to Se's robust oxidative resistance. Here we report a selective oxidation strategy utilizing Se's strong antioxidative property to remove coexisting narrow‐band gap Te impurities from Se feedstocks. This strategy selectively oxidizes volatile Te impurities into involatile TeO2 that remains in the evaporation source, while only volatile Se deposits onto the substrate during the thermal‐evaporation deposition process. This enables the fabrication of high‐purity Se films possessing a wide band gap of 1.88 eV, ideally suited to the optimal band gap for indoor photovoltaics (IPVs). The resulting Se photovoltaics exhibit an efficiency of 20.1 % under 1000‐lux indoor illumination, outperforming market‐dominant amorphous silicon and all types of lead‐free perovskite IPVs. Unencapsulated Se devices show no efficiency degradation after 20,000 hours of storage in ambient atmosphere.

Lanthanide-Like Contraction Enables the Fabrication of High-Purity Selenium Films for Efficient Indoor Photovoltaics.

The lanthanide contraction involves a reduction in atomic radius among f-block elements below the expected level. A similar contraction is observed in group-16 elements. The atomic radius of Se (117 pm) is slightly larger than that of S (104 pm) arising from the presence of d electrons, compared to the significant increase in atomic radius from O (73 pm) to S. This lanthanide-like contraction contributes to Se's robust oxidative resistance. Here we report a selective oxidation strategy utilizing Se's strong antioxidative property to remove coexisting narrow-band gap Te impurities from Se feedstocks. This strategy selectively oxidizes volatile Te impurities into involatile TeO2 that remains in the evaporation source, while only volatile Se deposits onto the substrate during the thermal-evaporation deposition process. This enables the fabrication of high-purity Se films possessing a wide band gap of 1.88 eV, ideally suited to the optimal band gap for indoor photovoltaics (IPVs). The resulting Se photovoltaics exhibit an efficiency of 20.1 % under 1000-lux indoor illumination, outperforming market-dominant amorphous silicon and all types of lead-free perovskite IPVs. Unencapsulated Se devices show no efficiency degradation after 20,000 hours of storage in ambient atmosphere.

Deep indoor illumination estimation based on spherical gaussian representation with scene prior knowledge

High dynamic range (HDR) illumination estimation from a single low dynamic range image is a critical task in the fields of computer vision, graphics and augmented reality. However, directly learning the full HDR environment map or parametric lighting information from a single image is extremely difficult and inaccurate. As a result, we propose a two-stage network approach for illumination estimation that integrates spherical gaussian (SG) representation with scene prior knowledge. In the first stage, a convolutional neural network is utilized to generate material and geometric information about the scene, which serves as prior knowledge for lighting prediction. In the second stage, we model indoor environment illumination using 128 SG functions with fixed center direction and bandwidth, allowing only the amplitude to vary. Subsequently, a Transformer-based lighting parameter regressor is employed to capture the complex relationship between the input images with scene prior information and its SG illumination. Additionally, we introduce a hybrid loss function, which combines a masked loss for high-frequency illumination with a rendering loss for improving the visual quality. By training and evaluating the lighting model on the created SG illumination dataset, the proposed method achieves competitive results in both quantitative metrics and visual quality, outperforming state-of-the-art methods.

Dimerized Non-Fullerene Acceptor-based organic photovoltaics for Round-the-Clock functioning

Organic photovoltaics (OPVs) have emerged as a key sustainable energy technology capable of efficiently generating electricity from both direct sunlight and low-intensity indoor lighting. Despite ongoing research to improve their performance, limited efforts have been undertaken to develop OPVs that can operate consistently (24/7/365) under versatile lighting conditions. For effective utilization, OPVs must demonstrate efficient operation under both outdoor and indoor illumination conditions, generating sufficient electrical power to drive microelectronic devices. Low-bandgap non-fullerene acceptors (NFAs) in OPVs are limited by low open-circuit voltage (VOC) under indoor lighting, restricting their performance. While high-bandgap NFAs can improve indoor power-conversion efficiency (PCE) by elevating VOC, they may often reduce outdoor performance owing to reduced light harvesting. Thus, we developed OPVs using the oligomeric dimerized NFA DYBO, which simultaneously achieved an excellent PCE of 16.7 % under simulated solar illumination and a remarkable maximum power output density (Pmax) of 0.079 and 0.396 mW/cm2 under a 5,200 K LED and halogen lamp (1000 lx), respectively, attributed to elevated VOC and reduced short-circuit current density (JSC) losses. The optimized OPVs demonstrated PCEs nearly equivalent to those of the current state-of-the-art under indoor illumination, with a remarkable Pmax capable of autonomously powering a variety of microelectronic devices.

Indoor Environmental Quality in Portuguese Office Buildings: Influencing Factors and Impact of an Intervention Study

Office workers spend a considerable part of their day at the workplace, making it vital to ensure proper indoor environmental quality (IEQ) conditions in office buildings. This work aimed to identify significant factors influencing IEQ and assess the effectiveness of an environmental intervention program, which included the introduction of indoor plants, carbon dioxide (CO2) sensors, ventilation, and printer relocation (source control), in six modern office buildings in improving IEQ. Thirty office spaces in Porto, Portugal, were randomly divided into intervention and control groups. Indoor air quality, thermal comfort, illuminance, and noise were monitored before and after a 14-day intervention implementation. Occupancy, natural ventilation, floor type, and cleaning time significantly influenced IEQ levels. Biophilic interventions appeared to decrease volatile organic compound concentrations by 30%. Installing CO2 sensors and optimizing ventilation strategies in an office that mainly relies on natural ventilation effectively improved air renewal and resulted in a 28% decrease in CO2 levels. The implementation of a source control intervention led to a decrease in ultrafine particle and ozone concentrations by 14% and 85%, respectively. However, an unexpected increase in airborne particle levels was detected. Overall, for a sample of offices that presented acceptable IEQ levels, the intervention program had only minor or inconsistent impacts. Offices with declared IEQ problems are prime candidates for further research to fully understand the potential of environmental interventions.

Performance testing of an innovative integrated zenithal daylight guide with solar water heater under real-weather conditions

Zenithal Daylight Guides (ZDG) and Solar Water Heaters (SWH) are individual energy-saving solutions utilized across diverse building types. This study proposes an innovative integrated power-saving system, uniting ZDG and SWH into a single model. The integration concept is rooted in leveraging the available space surrounding the daylighting device's pipe to incorporate a solar heater via a serpentine collector. The primary aim of this amalgamation is to optimize solar energy savings, minimize spatial demands, and alleviate manufacturing expenses. Moreover, the impetus behind this study stems from the recent emergence of daytime power outages in Egypt, attributed to heightened consumption surpassing production capacities. The ZDG is still not well known in Egypt. This is the only study until the year 2022/2023 in Aswan, Egypt, that analyzes the performance of this device under extreme sunlight conditions (with maximum global illumination reaching approximately 118 Klux). Across various seasons, the lighting and thermal efficacy of the current model underwent experimental testing and analysis to assess its practical utility. The integrated system effectively elevated the water temperature and achieved adequate light transmission, as indicated by the obtained results. The average transmitted indoor illumination on the work surface reached approximately 2470 lux. The reliance on electrical lighting could be mitigated for up to 5 hours. On the other hand, the highest water temperature and maximum instantaneous efficiency reached are about 70°C and 37%, respectively. Throughout the experiments, the proposed solar heater achieved a maximum daily thermal efficiency of 31.5%. The findings are deemed satisfactory and promising.

Inactivation kinetics of dairy phages using photocatalytic paint under diverse environmental conditions and radiation sources

This article investigates the efficacy of a photocatalytic paint for bacteriophages inactivation under various levels of incident radiation flux, relative humidity and radiation sources. Two phages that infect lactic acid bacteria were selected: J-1, infective of Lacticaseibacillus casei ATCC 27139, and M13-G1b, infective of Streptococcus thermophilus G1b. Phage suspensions were deposited on coated and uncoated plates and exposed to radiation typically used for indoor illumination (λ = 360–720 nm). A first-order inactivation kinetics was proposed with respect to the Plaque Forming Units per mL (PFU/mL) that correlates the inactivation constant with the operating conditions. The kinetic constant of this novel model combines a potential function for the incident radiation flux and a logistic function for the relative humidity. The results showed that as these variables increased, phage inactivation turned higher for both uncoated and coated plates. Photonic and quantum efficiencies were also calculated for both phages, when treated with photocatalytic paint under UV-A radiation. The photonic efficiencies were 8.03 × 1012 PFU/Einstein for J-1 and 4.05 × 1012 PFU/Einstein for M13-G1b, while the quantum efficiencies were 1.19 × 1013 PFU/Einstein for J-1 and 6.03 × 1012 PFU/Einstein for M13-G1b. Good agreement was obtained between predictions of the proposed kinetic model and experimental data, with a Root Mean Square Error of 4.43 % for J-1 and 2.98 % for M13-G1b. The developed model would be useful to predict phage inactivation under diverse combinations of operating conditions levels in environments of dairy plants, different from those tested in this work.

Comparative analysis of hydrogel-based thermotropic glazing and fixed horizontal overhangs in building performance

Thermotropic (TT) glazing is able to achieve energy-saving capabilities similar to external shading devices by dynamically regulating solar heat gain transmitted through windows in response to ambient climatic conditions. However, the building performance of TT glazing compared to traditional shading devices remains underexplored. This study aims to bridge this knowledge gap by comparing the building performance of hydrogel-based TT glazing and fixed horizontal external shading devices in terms of building energy consumption, daylighting performance, and thermal comfort. Experimental tests were conducted over a continuous ten-day period, focusing on the indoor temperature and illumination distribution within experimental rooms equipped with either TT glazing or fixed horizontal external shading device. Building performance models were developed using EnergyPlus and validated with experimental data. Subsequently, a comparative analysis was then conducted to evaluate the impact of TT glazings and fixed horizontal external shading devices on building energy consumption, daylighting performance, and thermal comfort across five typical climate conditions in China. The findings indicated that: (1) In five climate zones, TT provided the greatest energy savings in West-facing orientations, followed by East-facing orientations. (2) TT can replace fixed horizontal external shading device with a certain length to achieve similar building energy efficiency and indoor thermal comfort performance. (3) In regard to daylighting performance, TT achieved the desired values of sUDI<100lx,50 % and sUDI300–3000lx,50 % across all four orientations in the five climates. (4) In terms of thermal comfort, TT improved thermal comfort by reducing the annual daytime average PPDoverheating across all orientations in the five climate zones.

A study on the enhancement of energy efficiency and indoor environment through the integration of solar photovoltaic modules in daylighting louver systems

The global energy demand is predicted to increase significantly, with a strong link between energy consumption and CO2 emissions. Lighting energy accounts for a substantial proportion of total energy consumption in buildings, with the potential to be reduced using daylighting louvers. Despite some drawbacks, integrating solar photovoltaic modules with louvers could enhance energy efficiency while addressing the increasing demand for renewable energy systems in new buildings. Therefore, this study explores the potential benefits of integrating solar photovoltaic (PV) modules into a daylighting louver system to simultaneously reduce lighting, cooling, and heating loads and generate solar power. The performance of the proposed louver system was experimentally compared to a conventional building-integrated photovoltaic (BIPV) system installed on a window. The daylighting louver system demonstrated significant improvements in indoor illumination and occupants’ experience compared to the BIPV system. Furthermore, the indoor air temperature in the space with the louver system increased by about 5 degrees compared to the BIPV system, indicating its contribution to heating load reduction. The power generation performance of the louver system reached up to 65 % of the BIPV system, with a total cumulative electricity generation of 64 %. The results suggest that the daylighting louver system can be expanded to enhance its efficiency and address the increasing demand for renewable energy system installations in new buildings. Future studies should investigate the potential of 2-axis or 3-axis louvers to further improve the system’s efficiency.