Overcast Sky Research Articles

Testing the use of daylight-linked control systems to address integrative lighting and energy savings in office buildings

Daylight-linked control systems (DLCSs) are used to maintain constant work plane illuminance and save energy. If properly calibrated, they could be used to guarantee circadian requirements fulfilment as well. In this study, the functioning of a closed-loop proportional dimming system is simulated based on on-field measurements. Simulations are performed calibrating the system to achieve different targets: three work plane task illuminances (300 lx, 500 lx, 750 lx) and one melanopic equivalent daylight illuminance (melEDI) value (250 lx) alternatively. Four electric light CCT profiles (stable at 3000 K, 4000 K, and 6500 K, and variable during the day) are considered. Results demonstrate that when the system is calibrated according to work plane illuminance, melEDI values are always fulfilled under clear sky and with overcast sky when task illuminance and CCT are high. When the system is calibrated to meet circadian requirements, the CCT choice is crucial to guarantee work plane illuminance.

Enhancing daylighting predictions in urban planning: A workflow for setting bespoke Vertical Sky Component (VSC) targets

In Sweden, urban planners are legally obligated to design neighbourhoods that allow future buildings to meet daylight requirements. However, this is challenging because planners can only define the building masses, without control over future building details such as glazing ratios, room layouts, and orientation.The Vertical Sky Component (VSC) is a well-established indicator for early daylight assessments of buildings, and it is often used by Swedish urban planners to verify daylight access for their massing designs, even though it has its limitations. A VSC target value VSC ≥ 27 % has been widely applied in the urban planning practice. However, a single universal VSC target does not necessarily guarantee compliance with daylight requirements indoors. This article proposes a workflow for setting bespoke VSC targets. The goal is to provide urban planners with more reliable tools for early daylighting predictions. The workflow uses parametric simulations to establish VSC thresholds that assure compliance with current daylight regulations, such as the Swedish building code (BBR) and the European standard (EN 17037). While this article focuses on Sweden, the workflow could be readily applied to any location with prevalence of overcast sky conditions. Some potential practical urban planning applications of the workflow are suggested.

Large-Scale carbon Fiber-Based Solar-Driven evaporator with 1T MoS2-MXene Heterostructure: Towards reliable mechanical performance and efficient seawater desalination

Solar-driven interfacial water evaporation is often regarded as a promising method for producing fresh water from seawater. However, developing an evaporator with an ideal evaporation rate and efficient seawater desalination capabilities remains a significant challenge, especially when considering the mechanical performance requirements in large-scale practical use. Based on this, this work proposed a Janus-structured 3D carbon fiber (CF)-reinforced solar-driven evaporator fabricated through a vacuum-assisted infusion process (VAIP). A heterogeneous structure of 1 T MoS2-MXene, formed through ion embedding, was adorned on the surface to serve as an efficient photothermal conversion material. Due to the synergistic advantages, the Janus 1 T MoS2-MXene/ CSA/CF (JMMC) evaporator achieved excellent solar absorption efficiency of 94 % in the range of 200–2500 nm. The evaporator exhibited an evaporation enthalpy as low as 1556.4 kJ·kg−1, which facilitated the escape of water molecules at the interface. The JMMC evaporator delivered a high evaporation rate of 2.29 kg m-2h−1 and an efficiency of 93.8 % under the irradiation of 1 sun (1.0 kW/m−2(−|-)). The influence of the heterogeneous structure of 1 T MoS₂-MXene on the water evaporation rate was thoroughly assessed through molecular dynamics simulations. Besides, the mechanical performance of this evaporator was highly satisfactory, rendering it suitable for application in demanding and complex usage environments. Furthermore, its remarkable conductivity facilitated an excellent Joule heating effect even at low voltages, enabling water evaporation under challenging circumstances such as overcast skies or indoor settings. The versatility of this scalable evaporator holds great promise for addressing the issue of freshwater scarcity.

Reflection–Polarization Characteristics of Greenhouses Studied by Drone-Polarimetry Focusing on Polarized Light Pollution of Glass Surfaces

Drone-based imaging polarimetry is a valuable new tool for the remote sensing of the polarization characteristics of the Earth’s surface. After briefly reviewing two earlier drone-polarimetric studies, we present here the results of our drone-polarimetric campaigns, in which we measured the reflection–polarization patterns of greenhouses. From the measured patterns of the degree and angle of linear polarization of reflected light, we calculated the measure (plp) of polarized light pollution of glass surfaces. The knowledge of polarized light pollution is important for aquatic insect ecology, since polarotactic aquatic insects are the endangered victims of artificial horizontally polarized light sources. We found that the so-called Palm House of a botanical garden has only a low polarized light pollution, 3.6% ≤ plp ≤ 13.7%, while the greenhouses with tilted roofs are strongly polarized-light-polluting, with 24.8% ≤ plp ≤ 40.4%. Similarly, other tilted-roofed greenhouses contain very high polarized light pollution, plp ≤ 76.7%. Under overcast skies, the polarization patterns and plp values of greenhouses practically only depend on the direction of view relative to the glass surfaces, as the rotationally invariant diffuse cloud light is the only light source. However, under cloudless skies, the polarization patterns of glass surfaces significantly depend on the azimuth direction of view and its angle relative to the solar meridian because, in this case, sunlight is the dominant light source, rather than the sky. In the case of a given direction of view, those glass surfaces are the strongest polarized-light-polluting, from which sunlight and/or skylight is reflected at or near Brewster’s angle in a nearly vertical plane, i.e., with directions of polarization close to horizontal. Therefore, the plp value is usually greatest when the sun shines directly or from behind. The plp value of greenhouses is always the smallest in the green spectral range due to the green plants under the glass.

Daylighting Through Electrochromic Glazing Under Overcast Skies: Impacts on Visual Task Performance and Perception

ABSTRACT Electrochromic (EC) glazing allows modulating the intensity of visual and solar transmission by dynamically switching between bleached (clear) and tinted (colored) states, leading to changes in spectral power distribution (SPD), correlated color temperature (CCT), and illuminance of the incoming daylight. In this experimental study, we investigated the impact of spectral composition of daylight filtered through a 6-pane EC façade on visual task performance and visual perception. In a semi-controlled test room, 19 subjects were exposed to five setting scenarios of the EC façade (fully bleached, mixed setting after fully bleached, fully tinted, mixed setting after fully tinted, and user-controlled). Test subjects performed a series of visual tasks, and their assessments of the indoor environment and of the outside view were collected along with luminous and spectral measurements under each condition. The analysis provided statistical evidence that the changes in spectral composition of daylight do not have a practically relevant effect on visual task performance in terms of visual acuity and color naming accuracy. However, the daylight filtered through the fully tinted glazing had a substantive impact on visual perception, evoking negative responses to the color rendering of the indoor environment and of the outside view. A mixed settings of the EC façade could improve a natural assessment of the incoming light compared to the fully tinted state, achieving better ratings in terms of perception of the indoor and outdoor environments. When given control of the EC glazing, subjects expressed higher acceptance and satisfaction compared to the tinted and mixed scenarios.

POLarizer-FENestration (POLFEN) a novel concept of a glazing technology to modulate daylighting and glare in buildings

A conceptual new window/glazing technology called POLarizer-FENestration (POLFEN) is presented. In 1935, Edwin Land's pioneering work on polarizers successfully developed a sheet polarizer that was used in various applications. Subsequently, polarizers were employed in windows to modulate daylight and reduce associated glare. Early prototype windows were circular in shape so that the polarizing filter could be rotated to modulate the daylight. However, compared to rectangular-shaped windows that are ubiquitous, circular windows are rare in buildings. Therefore, a new window/glazing technology, discussed in this paper, was developed that utilizes a polarizing film in a conventional rectangular or square window, arranged in the form of strips or a checker-grid over the window panes to modulate daylighting levels and control glare. In this new research, a working prototype of the glazing technology is developed and demonstrated including simulations using the Radiance daylighting simulation software. In the current work, two types of measurements were taken: photographs of the indoor luminous environment and illumination levels (Lux) at selective points on the work-plane both in a physical prototype as well as in the simulation model under two sky conditions: CIE clear sky with sun, and overcast sky. The results indicate that the new glazing technology resulting from this concept can effectively modulate daylighting levels, minimized associated glare to an acceptable level while maintaining a view to the outdoor environment. The technology can be classified as Variable Transmission Glazing (VTG), similar to Electrochromic (EC) glazing since it also offers a dynamic modulation of solar optical properties (Tvis).

On the retrieval of cloud optical thickness from spectral radiances - A sensitivity study with high albedo surfaces

Measurements of spectral zenith radiance in the 320–950 nm wavelength range have been carried out since 2021 at the Thule High Arctic Atmospheric Observatory (THAAO, https://www.thuleatmos-it.it/, 76.5° N, 68.8° W, 225 m a.s.l) located in Pituffik, northern Greenland. This study evaluates whether such observations could provide, in principle, scientifically meaningful cloud optical depth (τ) estimates, what would be the limitations, which are the necessary auxiliary measurements, and which radiance wavelengths would be better suited for the goal. Although clouds play a critical role in the Arctic, a climatology of τ in high albedo conditions is particularly difficult to obtain. THAAO might have the instrument capabilities to provide such a long-term dataset. We use a radiative transfer package to simulate visible spectra with different cloud and surface conditions, assuming homogeneous overcast sky and liquid water clouds of fixed geometrical thickness. Simulations are run to reproduce typical conditions encountered at THAAO when measurements are carried out. We find that the assumption of a broadband albedo instead of a spectrally-resolved one is the source of the largest uncertainties. Tests on size and phase of cloud particles showed that a 50% uncertainty in reff leads to a ∼10% error in τ, and that a 10% contamination of ice crystals in a low-level liquid water cloud leads to an error in τ estimates of less than 5%. All the tests showed that the most critical τ range is between the thin and thick cloud regimes (τ ∼ 7–15), where the retrievals can be less reliable. Otherwise, tests suggest that in the environmental conditions that characterize late spring and summer at THAAO, and given the observatory measurements capabilities, estimates of τ for low-level clouds could be accurately retrieved both in high and low surface albedo conditions by means of zenith radiance measurements in the UV-Vis-NIR range.

A new spectrally-invariant approach to the remote sensing of inhomogeneous clouds

Current operational satellite retrievals of cloud optical and microphysical properties go back to the Nakajima-King technique developed at the end of the 1980 s. This technique is based on library calculations for plane-parallel homogeneous clouds. It often works well for overcast skies but leads to substantial errors for inhomogeneous and broken cloud fields where the plane-parallel-geometry assumption is no longer valid. The basic concept of a new technique was first introduced in nuclear physics to quantify the critical conditions of reactors. Based on the eigenvalues of the radiative transfer equation, their approach provides a powerful means to parameterize the structure of 3D media. This parameterization was later successfully applied to relate surface reflectance spectra to 3D canopy structure and is known as the spectrally-invariant approximation. The proposed approach adapts this technique to the remote sensing of cloud properties such as droplet single scattering albedo and the average number of scatterings (which are the fundamental parameters in radiative transfer theory), with an emphasis on quantifying the associated errors and uncertainties. This retrieval is free from the plane-parallel homogeneous cloud assumption.

Mapping flooded areas utilizing Google Earth Engine and open SAR data: a comprehensive approach for disaster response

One of the most destructive and frequent natural disasters in the world, flash floods cause millions of people to be displaced annually in addition to seriously harming livelihoods and infrastructure. It affects many ecological components and applications related to water management, natural resources, agriculture, human health, and economics. Himachal Pradesh saw an unprecedented amount of rainfall in June and July 2023, which resulted in exceptionally strong monsoon conditions from July 7 to July 10. Operating out of the Meteorological Centre in Shimla, the India Meteorological Department reported widespread, unusually heavy rainfall throughout the state during this time. Cloud cover often obstructs optical satellite data during the monsoon season, which has led to the investigation of alternate techniques for mapping floods. the whole satellite image processing process was carried out using Google Earth Engine (GEE). The Kangra District's 5739 km2 area was chosen as the study's area of interest. In these circumstances, traditional methods of mapping and monitoring flood-prone areas frequently fall short because of poor visibility and overcast skies during bad weather. Technology such as Synthetic Aperture Radar (SAR) becomes a ray of hope during these desperate times. When SAR data is combined with Google Earth Engine, it becomes even more user-friendly. Using SAR data and the powerful cloud processing platform Google Earth Engine (GEE), this study suggests a flood mapping technique. When it comes to mapping flood areas, the strength of SAR data and GEE surpasses boundaries and challenges. It is evidence of both technological advancement and human inventiveness. Such tools are more critical than ever as the world deals with the increasing effects of climate change and the rising frequency of extreme weather events.

Data quality processing for photovoltaic system measurements

The operation and maintenance activities in photovoltaic systems use meteorological and electrical measurements that must be reliable to check system performance. The International Electrotechnical Commission (IEC) standards have established general criteria to filter erroneous information; however, there is no standardized process for the evaluation of measurements. In the present work we developed 3 procedures to detect and correct measurements of a photovoltaic system based on the single diode model. The performance evaluation of each criterion was tested with 6 groups of experimental measurements from a 3 kWp installation. Based on the error of the 3 procedures performed, the most unfavorable case has been prioritized. Then, the reduction of errors between the estimated and measured value has been achieved, reducing the number of measurements to be corrected. For the clear sky categories, the coefficient of determination is 0.9975 and 0.9961 for the high irradiance profile. Although an increase of 2.5% for coefficient of determination has been achieved, the overcast sky categories should be analyzed in more detail. Finally, the different causes of measurement error should be analyzed, associated with calibration errors and sensor quality.

Image-registration-based solar meridian detection for accurate and robust polarization navigation.

Skylight polarization, inspired by the foraging behavior of insects, has been widely used for navigation for various platforms, such as robots, unmanned aerial vehicles, and others, owing to its stability and non-error-accumulation. Among the characteristics of skylight-polarized patterns, the angle of polarization (AOP) and the degree of polarization (DOP) are two of the most significant characteristics that provide abundant information regarding the position of the sun. In this study, we propose an accurate method for detecting the solar meridian for real-time bioinspired navigation through image registration. This method uses the AOP pattern to detect the solar meridian and eliminates the ambiguity between anti-solar meridian and solar meridian using the DOP pattern, resulting in an accurate heading of the observer. Simulation experiments demonstrated the superior performance of the proposed method compared to the alternative approaches. Field experiments demonstrate that the proposed method achieves real-time, robust, and accurate performance under different weather conditions with a root mean square error of 0.1° under a clear sky, 0.18° under an overcast sky with a thin layer of clouds, and 0.32° under an isolated thick cloud cover. Our findings suggest that the proposed method can be potentially used in skylight polarization for real-time and accurate navigation in GPS-denied environments.

The Performance of Anidolic Light Pipe Daylighting System in Office Building (Case Study : Bosowa Tower Makassar)

Producing available daylight in buildings is an important issue for reasons of energy efficiency. To make an office space that is comfortable for employees, the concept of daylighting quality must be considered. This research aims to examine intensity of natural lighting in the workspace of Bosowa Tower Makassar, and apply Anidolic Light Pipe (ALP) daylighting system in reducing the illumination value in the building perimeter area and increasing the illumination value in the deeper area. The research used quantitative methods, collecting information about measurements of the workspace’s existing condition and evaluating ALP performance on a physical model. The building’s south and north sides indicated high illumination values, especially under clear sky condition. On the other hand, the deeper part of the building receives little natural light and is therefore rather dark. According to ALP performance tests with physical scale model simulation in an overcast sky condition, it can be concluded that this daylighting system can reduce the illumination value by 15,01% at a distance of 0,5 m from the window due to its shading external, and was able to increase the illumination value by 394,92% at a distance of 11,5 m from the window.

Recommended control options of a daylight dimming system for daylit perimeter zones of open-planned office with curtain walls

This study investigates control options of a daylight dimming system in an open-planned office for required lighting environments with lighting energy savings and acceptable glare ratings. Computer simulations were performed for photosensors with three ranges of viewing angles in two daylit perimeter zones of the office and consecutive computational processes based on dimming control algorithm were employed for final light output of lighting fixtures. Three CIE standard sky and blind conditions were employed for the prediction of indoor daylight illuminance, photosensor illuminance, and daylight glare probability (DGP). The results indicate that the perceived glare can be imperceptible for the majority of time periods and a daylight dimming control system can be effectively applied for perimeter zones of office with curtain walls. For the south-facing zone under clear and intermediate sky conditions, the horizontal and 45 degree blind conditions are recommended to be combined with the full or partial photosensor shielding conditions for desirable dimming control performances. The unshielded photosensor condition should be generally avoided. For the east-facing zone under clear and intermediate sky, the photosensor sensing range should be narrowed using full shielding for the improvement of system performance of daylight dimming control. The unshielded and partially-shielded photosensors are rarely recommended. For the east and south-facing zone under overcast sky, effective control performance was rarely achieved due to the lack of daylight. Predictions models for linear relationships between the workplane and photosensor illuminances due to daylight were statistically acceptable, and strong relationships existed between them.

Daylight performance of the Modified Double Light Pipe (MDLP) through yearly experimental tests on a scale model of the system

This work focuses on the Modified Double Light Pipe (MDLP), a daylighting system designed to improve the performance of the Double Light Pipe (DLP).The paper shows the results of a yearly experimental activity carried out on a 1:2 scale model of the device. The dynamic metrics DA, cDA, and U0 have been calculated on a seasonal and yearly basis, and the internal illuminance trend has been determined in four representative days: winter and summer solstices, and spring and autumn equinoxes.The system is effective in delivering daylight in underground areas of buildings both on sunny and cloudy days. Particularly, under overcast sky, a good congruence between internal and external illuminances happens, and linear regression equations allow us to determine the internal illuminance as a function of the external one. Under clear sky with sun, this correlation is less precise at the corners of the room, due to the presence of direct solar radiation, while remaining accurate in the central area. The daylight autonomy is significant for target values of 50 and 100 lx, particularly in spring and summer. DA100 ranges between 0.58 and 0.83 in spring and between 0.66 and 0.83 in summer. The uniformity of daylight distribution on the horizontal work plane can be considered acceptable quite in all climatic conditions, particularly in spring and summer with U0 higher than 0.7 in 81 % (spring) and 85 % (summer) of cases. Altogether, the results can be considered satisfactory.

Full-scale validation of PCM-window energy model using the coupled thermo-optical approach

The aim of the presented study is an empirical validation of a novel energy model based on the Moving Mushy Volume approach using results of real-scale, long-term experiments. The model is based on the Control Volume and Net Radiation methods with the main objective set as the ability to simulate changing optical and physical properties of PCM in long-term simulations which is novel compared to already existing models. In order to do so the PCM domain was divided into sub-volumes in which the physical state could be analysed separately. The experiments were conducted under temper climatic conditions using a PCM window installed on a façade of the experimental room. The validation days were chosen so that a full solid-to-liquid transition occurred on one day, and the material was fully solidified during the following night. Selected sunny days were characterised by clear and overcast sky conditions. The results reveal a good agreement between the experiment and simulation, although the authors assumed a 1D heat transfer model in the PCM layer.

Assessing Window Design's Impact on Daylight Uniformity in Classrooms in Patna, India

Windows play a vital role in daylight infusion, significantly impacting indoor visual comfort. Various metrics exist for evaluating visual comfort in which the uniformity ratio falls under the distribution category and is as crucial as illuminance levels. This ratio effectively reduces the likelihood of glare and the need for artificial lighting. The primary objective of this research is to assess the impact of window design on daylight uniformity ratio in a classroom setting. In pursuit of this objective, a study investigated the uniformity ratio (Uo) of north-oriented and south-oriented classrooms of Kendriya Vidyalaya (KV) Khagual, Patna. The study considered five common shapes of windows (excluding the existing base cases) at different window-sill levels. Ninety simulations were run in the DesignBuilder software under overcast, intermediate, and clear sky conditions. To assess the uniformity ratio on three dates: March 21st, June 21st, and December 21st, which correspond to the highest, equinox, and lowest solar availability during the year under intermediate and clear sky conditions at three distinct times. The omission of the specific time and date for overcast conditions and the particular year for clear and intermediate sky conditions is justified as the outcome remains consistent throughout all years. The results show that the window design and sill level significantly affect the uniformity ratio. The research findings show that window design in Case 9 at a sill of 1230 mm and lintel of 3050 mm (just below the slab) consistently produces the best uniformity ratio across all sky conditions, independent of classroom orientation. This paper offers valuable design recommendations by comparing the uniformity ratio for five commonly used window designs. This is one of the first studies of window design and position to evaluate the uniformity ratio in the classrooms at Patna.

Computational analysis and optimization of daylight collector geometry for removal of hotspots in circular mirror light pipe

The illuminance patterns formed on the various surfaces of a tubular daylight guidance system (TDGS) were numerically measured and calculated for the beam sunlight input. For this study, the TDGS comprises a revolved parabolic profiled daylight collector geometry and a vertical MLP system for daylight guidance. TDGS is basically a non-imaging optical system that is designed to efficiently transmit available sunlight across the MLP (mirror light pipe) length. But while doing so the problematic hotspots are observed mainly on the diffuser placed at the exit aperture of cylindrical MLP which further results in non-uniform illumination in the daylit room. In this work, the use of a prismatic casing arranged sideways to the parabolic profiled collector and a sloped diffuser as a top cover shows a significant reduction in the hotspot problem on the exit aperture of MLP without compromising light transmission in TDGS. The ‘non-uniformity’ index value, Ir signifying the ratio of maximum illuminance to average illuminance on the diffuser surface dropped considerably for the proposed design signifying an increase in uniformity on the exit aperture of MLP. For 1 m long MLP (aspect ratio = 2.5), the maximum value of Ir was ∼ 19 and ∼ 37 for TDGS with dome collector and TDGS with parabolic collector having plane cover (TSA) respectively on midday timings of 21st June while for the proposed design the value was Ir < 5. For 2 m long MLP (aspect ratio = 5), the value was Ir < 4 much lower in comparison to Ir of ∼ 20 and ∼ 36 for TS with dome collector and TSA respectively. A considerable decrease in the severity of hotspots was realized from the results. The proposed collector design was also tested for the illuminance values on the work plane of the simulated room under beam sunlight, diffuse skylight, and overcast sky conditions. No compromise in the average illuminance values was observed when compared to the parabolic collector with transparent casing. Moreover, the proposed design gave enhanced values of illuminance under low altitude beam sunlight as well as under diffuse skylight for various timings of the day. Performance under the overcast sky was found slightly lesser in comparison to conventional collector designs though nominal levels of illuminance were observed for all the configurations of collectors due to the very less magnitude of light availability.

Ultraviolet Erythemal Irradiance (UVER) under Different Sky Conditions in Burgos, Spain: Multilinear Regression and Artificial Neural Network Models

Different strategies for modeling Global Horizontal UltraViolet Erythemal irradiance (GHUVE) based on meteorological parameters measured in Burgos (Spain) have been developed. The experimental campaign ran from September 2020 to June 2022. The selection of relevant variables for modeling was based on Pearson’s correlation coefficient. Multilinear Regression Model (MLR) and artificial neural network (ANN) techniques were employed to model GHUVE under different sky conditions (all skies, overcast, intermediate, and clear skies), classified according to the CIE standard on a 10 min basis. ANN models of GHUVE outperform those based on MLR according to the traditional statistical indices used in this study (R2, MBE, and nRMSE). Moreover, the work proposes a simple all-sky ANN model of GHUVE based on usually recorded variables at ground meteorological stations.

New Feature Selection Approach for Photovoltaïc Power Forecasting Using KCDE

Feature selection helps improve the accuracy and computational time of solar forecasting. However, FS is often passed by or conducted with methods that do not suit the solar forecasting issue, such as filter or linear methods. In this study, we propose a wrapper method termed Sequential Forward Selection (SFS), with a Kernel Conditional Density Estimator (KCDE) named SFS-KCDE, as FS to forecast day-ahead regional PV power production in French Guiana. This method was compared to three other FS methods used in earlier studies: the Pearson correlation method, the RReliefF (RRF) method, and SFS using a linear regression. It has been shown that SFS-KCDE outperforms other FS methods, particularly for overcast sky conditions. Moreover, Wrapper methods show better forecasting performance than filter methods and should be used.

An Analysis of Day-Lighting Quality of an Architectural Design Studio: A Case Study on a Design Studio of Chattogram

Day-lighting is correlated to the optimum output of the specific purpose of any interior space for which the building infrastructure is constructed. When it comes about designing a studio for student of architecture, it becomes more important because of its connection to creative work. The close link between daylight and productivity is evident from many literatures. However, due to the availability of electricity and provision of different artificial lighting, natural lighting strategies became negligible by designers. But with the rising concern of achieving sustainability, designers now try to revitalize day-lighting strategies in building construction. For this purpose, we need to evaluate the current situation of a space and find out the problem. This paper focuses to evaluate the current day-lighting quality of an architecture studio at two different days: one is typical clear sky day and another is overcast sky day. The finding indicates that adequate windows are provided in this studio which causes it illuminate within range during typical clear sky days but artificial lighting is required when the sky is over casted. Key Words: lighting, studio, illuminance level, window