Daylight Availability Research Articles

Analysing the Daylighting Performance of the Main Prayer-hall in the Great Mosque of Hama, Syria

Daylighting and solar availability at urban scale has come to play a crucial role in the perception of discomfort conditions for people, both in outdoor and indoor spaces, and on the energy consumption of buildings. Daylighting and solar analyses are typically done separately. The paper presents a novel method, called the ‘sunlight-daylight signature’ (SDS), which allows the qualitative analysis of urban settings with respect to sunlight and daylight. The method can be used to classify different urban settings in terms of daylight/sunlight access or to test new development proposals by referring to existing locations and confirm whether a certain daylight quality is met. The SDS relies on a new analysis tool, called ‘sunlight-daylight wedge’ (SDW), which combines obstruction (through the vertical sky component VSC) and sunlight access (through the annual probable sunlight hours PASH and the winter probable sunlight hours PWSH). The orientation of the façade at each point is also included as it will affect the times of the day when the sun-hours from PASH and PWSH occur, thus affecting the character of the corresponding sunlight. The SDS approach is based on a clustering technique to subdivide large datasets (in this case, daylight data points across entire cities or major urban areas) into smaller groups, using machine learning by way of the k-medoids clustering technique. This is used to derive typical daylight and sunlight scenarios representing groups of data points with similar conditions. Additional data is included to account for urban density and daylight availability in public areas. Final output of the clustering process consists of a map showing areas with the same daylight signature (SDS), which means areas with the same sunlight and daylight conditions. The SDS can be useful for urban planners and building practitioners to predict the access to both daylight and sunlight of large urban settings to optimize comfort for people and energy usage.

The impacts of urban canyons morphology on daylight availability and energy consumption of buildings in a hot-summer Mediterranean climate

Proper sunlight access has a positive impact on the physical and mental health of citizens, as well as on reducing energy consumption. This capacity may be limited by inappropriate urban morphology, and urban canyons and buildings are deprived of proper daylight. The purpose of this research is to study the current solar potential on the surface of the canyons and buildings and the effect of urban morphology parameters on the amount of each of the main variables of the research in Ilam, Iran. First, solar radiation, daylight illuminance, and air temperature were measured at different points of the studied canyons for three days. After that, the studied area was modeled with Rhino-Grasshopper software, and simulation was done using Ladybug Tools and UMI plugin. The results showed that the amount of daylight available in most canyons is low. Less than 30 % of the canyon’s surfaces benefited from 6 h of direct sunlight during the measurement. The simulation results for the 62 studied buildings showed that the highest amount of daylight is related to buildings with a height of more than 10 m. 56 % of the buildings had an annual solar radiation of less than 500 mw/m2. The roofs of the buildings received the most radiation, accounting for 72 % of the total radiation. By examining the parameters of urban morphology, it was found that the most influential parameter on the amount of solar radiation was the floor area, and the height of the buildings had the most influence on energy consumption.

Simulating the annual energy demand to meet non-visual health recommendations from a luminaire level lighting control system

This paper introduces a digital simulation workflow that calculates annual eye-level illuminance and energy demand from daylight and electric lighting sources for an array of view positions across 9-channels of spectral data. This Radiance-based workflow combines parts of the LARK spectral lighting code to offer better spectral resolution and accuracy when computing melanopic lx to evaluate the non-visual health potential for view positions within a digital model. The authors have implemented a series of annual climate-driven simulations and post-processed time-series of resulting data using the R statistical analysis software to compute Equivalent Melanopic Lux (EML) and energy demand (kWh) for an array of view positions and view directions in a digital model. This allows us to compute the energy demand of a given lighting and shading control scenario, which is optimized by hourly daylight availability to meet a recommended level of melanopic lx. This combined workflow uses digital models of an interior space to evaluate the annual potential of non-visual light exposure under different architectural, lighting, and shading control scenarios. This paper demonstrate the utility of this workflow by evaluating a luminaire-level lighting controls (LLLC) system to meet eye-level light exposure recommendations from the WELL Building Institute Feature L03 Circadian Lighting Design and compare the energy demand between targeted melanopic lux thresholds and shading control scenarios.

Energy efficiency of commercial offices by luminous retrofit

Lighting is one of the systems that mostly consume electricity in commercial buildings. Therefore, improving its efficiency has the potential to reduce electricity consumption and emission of polluting gases. The objective of the present study was to assess an office lighting system retrofit of an existing building from the 1990s, verify the light levels in relation to standards of the Brazilian requirements, and to explore new systems with potential for luminous and energy improvement. The analyzes were carried out through computer simulations using the DIALux evo software, which allows the evaluation of artificial and natural illuminations simultaneously. The results indicated that the existing lighting system does not meet the average illuminance standard value for office environment. From simulations with new arrangements and types of luminaires and lamps, two more efficient lighting systems were designed. The first presented savings of 15.5% in lighting energy when replacing T12 fluorescent lamps with LED luminaires. The second system considered the use of natural light and was complemented by artificial lighting with the aid of a dimming system linked to the availability of daylight, and presented up to 67% less electric energy consumption when compared to the existing lighting system in the environments. Therefore, it was possible to propose actions to the existing lighting system retrofit and, thus, offer better visual comfort to users and at the same time save energy.

Daylight Analysis in Terms of Building Direction and One-Way Roof

The location of the buildings in the residential area is very important in protecting or benefiting from sunlight. The dynamic structure of the sun, which constantly changes according to time and seasons, directly affects the building's architecture and urban formation. Ignoring the sun's use of the structures during the construction of the buildings can cause significant disturbances to the residents. Daylight strategies, which are also influenced by climate, depend on the availability of natural light, determined by the latitude of the building site and the instantaneous conditions around the building. High latitudes have different summer and winter conditions, with lower daylight levels in winter. At these latitudes, designers often aim to maximize daylight penetration in buildings. In the tropics, where daylight levels are high throughout the year, the design emphasis is often on preventing overheating by limiting the amount of sunlight entering the building. Daylight availability depends not only on latitude, but also on the orientation of a building, and each facade and material of the building requires a different design importance. Therefore, daylight and architectural design strategies are two inseparable phenomena. In this respect, examining traditional architecture and successful natural lighting designs in the past is very useful for understanding climate-balanced building design. For this purpose, determining the roof slope according to the sun angle in architectural structures by calculating according to the location provides efficiency in many issues from energy efficiency to human health.

Sunlight-Daylight Signature: a Novel Concept to Assess Sunlight and Daylight Availability at Urban Scale

Daylighting and solar availability at urban scale has come to play a crucial role in the perception of discomfort conditions for people, both in outdoor and indoor spaces, and on the energy consumption of buildings. Daylighting and solar analyses are typically done separately. The paper presents a novel method, called the ‘sunlight-daylight signature’ (SDS), which allows the qualitative analysis of urban settings with respect to sunlight and daylight. The method can be used to classify different urban settings in terms of daylight/sunlight access or to test new development proposals by referring to existing locations and confirm whether a certain daylight quality is met. The SDS relies on a new analysis tool, called ‘sunlight-daylight wedge’ (SDW), which combines obstruction (through the vertical sky component VSC) and sunlight access (through the annual probable sunlight hours PASH and the winter probable sunlight hours PWSH). The orientation of the façade at each point is also included as it will affect the times of the day when the sun-hours from PASH and PWSH occur, thus affecting the character of the corresponding sunlight. The SDS approach is based on a clustering technique to subdivide large datasets (in this case, daylight data points across entire cities or major urban areas) into smaller groups, using machine learning by way of the k-medoids clustering technique. This is used to derive typical daylight and sunlight scenarios representing groups of data points with similar conditions. Additional data is included to account for urban density and daylight availability in public areas. Final output of the clustering process consists of a map showing areas with the same daylight signature (SDS), which means areas with the same sunlight and daylight conditions. The SDS can be useful for urban planners and building practitioners to predict the access to both daylight and sunlight of large urban settings to optimize comfort for people and energy usage.

Ideal thermochromic smart window in a south-facing office room of China considering daylighting and energy performance

ABSTRACT Thermochromic (TC) smart window which allows modulating the transmission of solar heat energy and sunlight in response to environmental conditions has great potential for improving the building energy and daylighting performance simultaneously. In this study, the multi-objective optimization method is used to determine the ideal optical properties of TC windows. Parametric assessment is firstly conducted to investigate the influence of several crucial parameters. Multi-objective optimization is then carried out by applying Non-dominated Sort Genetic Algorithm-III, maximizing daylight availability and building energy efficiency. Finally, the decision-making of the Pareto frontier is performed to achieve the ideal TC windows in 32 representative cities in different climatic zones of China. Results demonstrate that increasing the luminous transmittance at low-temperature and decreasing luminous transmittance modulation ability are beneficial to daylighting and energy performance. Lower solar transmittance at low-temperature contributes to building energy savings in Beijing, Shanghai, Guangzhou and Kunming, except for Harbin. Higher solar transmittance modulation ability is desired for building energy efficiency. The optimum value for the transition temperature is in the range of 23.67–38.85°C. The building energy consumption can be reduced by 13.01%, and the desired daylighting hours can be improved by 8.90%, relative to the clear double-glazed windows.

Façade design of side-lit spaces for different climates and surroundings by machine learning and NSGAIII

This work aims to propose a simplified decision tool for the design of side-lit spaces that accounts for the impacts of climate and surroundings. The framework was developed using a smart optimization algorithm NSGA-III in combination with CatBoost ensemble machine learning technique and simulation. WWRs and overhang depths were optimized to maximize daylight penetration, minimize glare risk and reduce energy demand in different climates, orientations, space proportions, and surrounding obstruction angles. Besides, optimal solutions were used to determine the range of attainable targets for daylight, glare, and energy metrics in each climate, which can be used as requirements of national codes and standards. For example, for WDR = 3:2 and an OA of 20, energy demand varied between 260 and 266 kWh/m2, ASE remained at 40–50%, and sDA was reported 100% for south-oriented cases in Tehran. A sensitivity analysis was also performed to provide insights into how various design parameters affected daylight and energy performance in architectural spaces. The results revealed that daylight availability metrics were highly sensitive to the Window-to-Wall Ratio (WWR), while glare metrics were primarily affected by obstruction angle. Energy consumption was mainly influenced by room depth, WWR, window orientation, and obstruction angle. Notably, these parameters ranked similarly across all considered climates, albeit with varying degrees of significance. Results were presented in the form of guide charts that offer a practical tool for designing buildings in highly obstructed contexts and enable non-programmer architects and designers to make informed decisions.

A design methodology to consider occupants’ spatial adjustment and manage view content in adaptive façade design for improving visual comfort

ABSTRACT Occupants’ spatial adjustment (OSA) is one of the critical adaptive behaviours in buildings because it affects occupants’ comfort and contents of view. However, OSA for contents of view management from facade (e.g. sky, other construction, and greenery) have not been quantified to be integrated into other aspects of multi-objective building design, particularly façade design. The current study develops a design methodology and a correspondent plugin tool to incorporate OSA and content view calculation for visual comfort improvement. To this end, first, a test cell and outdoor and indoor environment were modelled, and façade geometric variables and OSA variables (location and direction of occupant’s sight) were set. After that, images were captured from hypothetical occupants’ locations inside in different directions of sight while façade transformation alternatives were recorded to the occupants’ content view images. Next, python image processing was linked to the Grasshopper modelling environment for content view analysing and quantification to be integrated into the optimisation process linked with visual comfort objectives. The designed methodology helped improve occupants’ visual comfort by optimising façade form and managing OSA for optimum daylight availability, glare minimisation, and enhancing occupants’ content view. Illuminance and discomfort glare probability (DGP), useful daylight illuminance (UDI), and spatial daylight autonomy (sDA) were used to shed light on the daylight performance of the proposed scenarios. Results demonstrated that a unique OSA and integrated façade configuration at any point in time and seasons that are suitable for the occupant’s daylight availability management, decreases perceived glare, and enhances the content view.

Reducing Lighting Energy Use in Controlled Agricultural Environments

Photometric simulations using both daylight and electric lighting were performed to compare the energy use of conventional high-pressure sodium (HPS) greenhouse lighting to that of light-emitting diode (LED) lighting. Photometric simulations of a hypothetical greenhouse were performed in three different geographic locations in the United States with widely different annual daylight availability: Albany, NY, Fairbanks, AK, and Phoenix, AZ. Simulation conditions included summer and winter, overcast and clear skies, and several lighting layouts and distributions. The analysis showed that, while maintaining the criteria levels of photosynthetic photon flux density, lighting energy savings were primarily attributable to increased LED source efficacy rather than HPS. Secondary energy savings were attributable to the ability to continuously dim LED lighting in response to daily and seasonal changes in daylight. Despite options for LED luminaires with a slim form factor, reduced crop shading compared with larger conventional HPS luminaires did not result in significant lighting energy savings.

A Design Proposal for Improving Daylight Availability of a Deep-Plan Classroom by Using Tubular Daylight Guidance Systems and Movable Shading Devices

The use of daylight in educational settings has a significant impact on the well-being, attention, and academic achievement of students. However, providing adequate daylighting without glare can be difficult, especially in deep-plan layout classrooms, because daylight is not constant and its strength varies with distance from the façade, necessitating the use of additional solutions frequently. In this study, tubular daylight guidance systems (TDGS) and movable shading devices are proposed to increase daylight availability in the Yaşar University Faculty of Architecture Temporary Studio, which has a deep plan layout and receives daylight only from the southeast facade. The objective was to meet the LEED daylight evaluation requirements for each zone, which require sDA to be at least 55% and ASE to be at most 10% in the selected analysis area. To propose TDGS and movable shadings with the most efficient angles and positions; Rhinoceros, Grasshopper, and Climate Studio were used, and simulation results were validated by real-time measurements. The design proposal simulation results achieved a significant increase in daylight availability in the rear part of the room (zone 2-3), while glare was diminished near the façade (zone1). The proposed design strategy improved daylight availability through the room, demonstrating that the systems perform well together.

Comparative assessment of optical characterization of prismatic materials (PMs), using genBSDF tool for virtual simulations and a goniophotometer for physical measurements

To improve daylight availability and thermal performance of buildings, complex fenestration systems are used to redirect/distribute solar radiation indoors. We need to characterize the optical properties of these complex fenestration systems through measuring their spectral, bidirectional distribution function to evaluate their performance for energy efficiency, daylight availability, and building sustainability purposes. This paper represents the characterization of two different Prismatic Material (PM) products that apply to diverse purposes in buildings. First, we conduct two methods to measure the Bidirectional Scattering Distribution Function (BSDF) of materials; genBSDF raytracing tool of Radiance and goniophotometer measurement (goniophotometry). In the next step, we compare the genBSDF result with the results of the goniophotometry. The aim of this study is to evaluate the angular-based optical behavior of prismatic materials in distributing light and also to assess the reliability of the genBSDF tool result for further simulation of high-performance building purposes. The results demonstrate that the genBSDF raytracing tool method creates a comparable result to the goniophotometry method. Therefore, genBSDF is a robust tool for assessing the solar-optical properties of PMs.

Simulation of daylight availability, visual comfort and view clarity for a novel window system with switchable blinds in classrooms

The presence of daylight reflections on blackboards in classrooms can be disruptive to students and negatively impact their visual comfort and learning efficiency. A novel window system with switchable blinds has been specifically designed to balance daylight availability, visual comfort, and adequate window view in classrooms. This study aims to develop a validated simulation method to assess the daylighting performance of the novel window system in these three domains. Radiance-based simulation using bidirectional scattering distribution function (BSDF) data was developed and validated against experimental measurements in a test room. Daylight autonomy (DA) was used as the criterion for daylight availability, while the contrast ratio on the board was used to evaluate the disturbing light reflections on it. The simulation results show that, regardless of the classroom orientation (south/east/west), the novel window system with switchable blinds can: a) successfully meet the LEED requirements for spatial daylight autonomy (sDA) > 55%; b) reduce the low-contrast areas on the blackboard by adaptively switching the blinds, and c) maintain a satisfactory openness of the window with a clear image of the exterior. The studied window system with switchable blinds can provide a sensible balance between daylight availability, visual comfort, and view. The method of rating visual comfort in classrooms using contrast ratio on the blackboard was demonstrated to be feasible and applicable.

Visual Comfort Assessment of Hospital Patient Rooms with Climate Responsive Facades

As advanced technologies become prevalent, they are being used more widely in numerous fields. The building sector is not an exception. One of these cutting-edge technologies is responsive facades, which are used in buildings and have an undeniable effect on daylighting. However, they have not been adequately evaluated for improving visual comfort in hospitals. This study investigates visual comfort in a standard patient room, based on applying four responsive facades. Simulations were conducted using HoneybeePlus, a plugin in the Grasshopper. Simulation-based results of annual indicators, including Annual Sunlight Exposure (ASE) and spatial Daylight Autonomy (sDA), showed that different facades could result in several optimal modes. Furthermore, a more comprehensive investigation should consider factors such as Daylight Glare Probability (DGP) and Daylight Glare Index (DGI). Glare indicators revealed that facade directly affects patient visual comfort and can even have an adverse effect. When the optimal responsive facade is chosen, it enhances users' visual comfort throughout the year, yet there will be still glare probability in some cases. Based on the results, this probability decreases as patient distance increases, and Window to Wall Ratio (WWR) is not particularly effective in reducing glare. Nevertheless, when it comes to daylight availability, WWR cannot be ignored, and the first façade with WWR 60% showed the best overall performance.

DAYLIGHTING PERFORMANCE OF HIGH SCHOOL LEARNING ENVIRONMENT IN TROPICS

ABSTRACT The quality of the indoor environment, including the lighting conditions, is crucial in classrooms as it directly affects students’ learning performance and productivity. Natural light is the best light source for visual comfort, aesthetics, and energy efficiency. Malaysia is in a tropical region and has abundant daylight availability that could meet the required lighting during the day. However, in Malaysian schools, electric lights are frequently switched on during classes in the daytime; hence, daylighting is not efficiently utilised. This study investigates the daylighting performance in classrooms in a national high school in Penang, Malaysia. Fieldwork was conducted by measuring incident illumination levels inside selected classrooms in the Teluk Kumbar High School. The results show that average illumination levels were between 400 lux to 1000 lux, more than enough in most classrooms because of the relatively large windows with clear glass. The average daylight ratios recorded in the classrooms were between 6.4 and 9.2%, which may result in glare problems. Simulations were conducted using Design-Builder to further evaluate the annual daylighting performance including Daylight Autonomy (DA), Annual Sun Exposure (ASE) and Useful Daylight Illuminance (UDI). Based on the findings, it is recommended to use shading devices or replace the glazing type to improve daylighting performance for visual comfort. Proper design and selection of windows in schools can significantly improve indoor lighting quality for students and reduce solar heat gain.

A Study on Daylight Performance Evaluation in Primary School Classrooms

From the early beginning of construction in history, priority of using daylight has played an active role in the settlement decision, building shape and façade design. Today, the necessity of conscious consumption has become an accepted fact due to the depletion of energy resources. For this reason, the effective use of daylight and reducing lighting energy consumption have become one of the most important goals of today's architecture. 
 The purpose of the natural lighting system is providing sufficient daylight to the target area, considering the visual comfort conditions. Nowadays, for the architectural design of buildings, the use of passive systems is primarily preferred in terms of energy efficiency. The use of natural lighting as a passive system, minimizing building lighting energy requirements and creating the desired visual environment should be prioritized in terms of providing visual comfort. In educational buildings, it is vital to design a lighting system in which daylight is used effectively in order to meet the visual needs of the instructors and students and to minimize the usage of lighting energy. Within the scope of the TS EN 17037 standard, which was developed for daylight assessment in buildings and approved by CEN on 29.07.2018 and lastly updated on 02.03.2022, the criteria for daylight assessment is handled under 4 headings: daylight provision, view out, exposure to sunlight and protection from glare. For each criteria specified in indoor daylight assessment, three grades are defined as 'minimum, medium and high'.
 In this study, the criterion of providing daylight in educational buildings was examined in accordance with the TS EN 17037 standard. With the study, it is aimed to develop an approach to determine the optimum values ​​of the parameters of direction, obstacle presence and transparency ratio in the context of providing sufficient daylight in the primary classroom design. Investigated building type is the primary school building classroom, which was created in optimum dimensions according to the characteristics of primary education classrooms defined in the ‘Educational Buildings Minimum Design Standards Guide’ published by the Ministry of National Education. It is aimed to evaluate and develop the criteria given in the ‘Educational Buildings Minimum Design Standards Guide’ according to the TS EN 17037 standard, which defines daylight performance in Turkey. The classroom model discussed within the scope of the study has been modeled with the Rhino program according to the alternative transparency rates and obstacle situations; In the simulation, the Climate Studio plugin, which was developed for the calculation of dynamic evaluation parameters, was used. The area handled by using evaluation methods according to the 17037 standard included in the software was evaluated in terms of annual daylight performance. The availability of target illuminance levels in half of the daylight hours throughout the year was calculated using the daylight autonomy method, and the climatic data of the province of Istanbul were used as a representative in the calculations. The results obtained were evaluated according to the TS EN 17037 Daylight Standard, and the scenarios created were classified as 'minimum, medium and high' according to the availability of daylight. According to this classification, optimum transparency ratio, window direction and obstacle conditions conditions for the city of Istanbul in primary school classroom design are discussed. The optimal transparency ratios for each aspect are discussed. The minimum transparency ratio values ​​given in the ‘Educational Buildings Minimum Design Standards Guide’ were compared with the optimum transparency ratios obtained.
 
 
 Keywords: Daylight Performance, TS EN 17037, Primary school classrooms, Window Design

A proposal on residential lighting design considering visual requirements, circadian factors and energy performance of lighting

ABSTRACT This study assesses residential areas which have been converted into workplaces and are still used after the Covid-19 in terms of visual, non-visual, and energy performance requirements of lighting. We proposed a lighting design using LED systems with dimmable and tuneable features. Circadian factors in WELL Building Standard are analyzed for compatibility with the current visual requirements. The impact of various design parameters on lighting energy consumption, including daylight availability, lighting schedules, lighting control strategies, and light reflectance value of walls is evaluated through a case study in Turkey. Although the annual lighting energy consumption is higher than it was before the pandemic, building energy simulation results show that the application of LED systems with lighting energy measures can improve lighting energy performance by up to 38%. From the non-visual dimension of light, our data indicate that higher melanopic illuminance and/or colour temperature of light sources are necessary to entrain and sustain the circadian rhythm under overcast sky conditions in winter months. On the other hand, an increase in luminous intensity can lead to glare and higher energy consumption while a higher colour temperature may affect the physiology and psychology of occupants negatively.

Daylight sufficiency of indoor environments under climate change scenarios

The bioclimatic performance of buildings under climate change scenarios has been extensively studied from a thermo-energy perspective but hardly studied at all from the perspective of indoor daylight sufficiency. This shortcoming is related to the invariability of radiation data in the available weather files of future scenarios. This research proposes identifying the impacts that the variability of radiation data in weather files of future scenarios would have on daylight sufficiency in indoor spaces. The methodology includes the adaptation of available weather files and the running of daylight simulations for hypothetical workspaces located in Medellín, Colombia. The results show differences in the Spatial Daylight Autonomy – SDA metric of up to 18% in different future scenarios. In conclusion, the need is outlined to refine predictions of outdoor daylight availability that allow improving daylight performance evaluations under climate change scenarios.

Contrast-based evaluation of the reflected daylight glare on the blackboard in a classroom with complex fenestration systems

Visual comfort within a classroom determines students’ concentration, productivity and well-being. The existing glare-based metric (e.g. Daylight Glare Probability, DGP) cannot reveal the visual comfort level when students look at notes written on the blackboard in a daylit classroom. Contrast-based metric has been proven as a more appreciate method for evaluating the vision within the area of a blackboard. The aim of this article is to explore the applicability of a contrast-based metric in evaluating classroom daylight design. The contrast-based metric was proposed based on the statistical results of a previous study on disturbing reflections on a blackboard. The evaluation method using contrast ratios within the blackboard area was established based on RADIANCE simulation and validated against experimental measurements. Bidirectional scattering distribution function (BSDF) data was used to model the complex fenestration systems (CFS) in the studied classroom. The validation results show that the error of simulated contrast ratio is within 17%. When using the contrast-based metric for assessing the studied classroom with different fenestration designs, the simulation results indicate that applying vertically placed daylight redirecting louver can significantly improve the contrast performance while maintain the daylight availability, providing design guidance for fenestration systems of classrooms. The simulation also illustrates that using DGP in a classroom leads to an underestimation of the glare level. This study contributes to expanding the knowledge on visual environment evaluations of classrooms, demonstrating the capacity of using contrast-based metric on determining disturbing glares in a classroom daylight design.

Experimental study on the impact of double tilted Venetian blinds on indoor daylight conditions

One of the most important concerns when designing buildings as liveable spaces is the indoor comfort. This depends on different factors, including daylight availability and discomfort glare conditions.The increasing use of glazing areas in the building's envelopes can lead to high energy consumption and problems such as visual discomfort. The use of shading devices stands out as a sustainable design strategy to reduce energy consumption in the buildings. This work presents an experimental analysis of the impact of an innovative shading device, a double-tilted venetian blind (DTVB) with different positions of upper and lower slats, on the indoor daylight conditions. Moreover, discomfort glare evaluation, through DGPs metric, is performed.The experimental campaign was conducted in an outdoor test cell during three periods of the year: summer solstice, winter solstice and autumn equinox. Experiments were carried out with both white and grey DTVBs, for several positions of upper and lower slats, under clear and overcast sky conditions. This comprises the measurement of indoor and outdoor horizontal and vertical illuminances and irradiances and solar and visible transmittance of the fenestration. It was concluded that DTVBs can achieve a higher performance, regarding solar protection, daylighting and glare control, when compared with more traditional venetian blinds systems.