Efektivitas Daylight Mirror Shaft sebagai Sistem Pencahayaan Alami Ruang Bawah Tanah pada Langit Tropis

Title: Effectiveness of Daylight Mirror Shafts as Natural Daylighting System for Basements under Tropic Sky Conditions Basements have lots of potential as functional spaces, but have mostly been neglected due to lighting issues. Therefore, this study will explore the daylight mirror shaft system as a daylight strategy for basements, which features the placement of a reflecting surface on a light shaft to redirect daylight. The system was introduced by Heliobus®, a daylighting company from Switzerland. To see the effectiveness of implementing the system in Indonesia, a study was made on its performance on the climate sky condition. Furthermore, a study was made on the effect of different opening orientations and light shaft placements toward the illuminance level achieved. The lighting data was obtained using the simulation softwares Lightstanza. Results show that the performance of the system on climate sky condition can provide sufficient light for 41% of a basement. The use of mirrors on the light shaft could also increase the lighting levels by 2.1 times compared to a shaft without a mirror. Moreover, it was found that different opening orientations and light shaft placements didn’t give a significant effect on the lighting quantity. Overall, the study shows that the system’s implementation on climate skies still require adjustments through further studies to be effective.

A new corresponding color dataset covering a wide luminance range under high dynamic range viewing condition

An experiment was carried out to investigate the change of color appearance for 13 surface stimuli viewed under a wide range of illuminance levels (15-32000 lux) using asymmetrical matching method. Addition to the above, in the visual field, observers viewed colours in a dark (10 lux) and a bright (200000 lux) illuminance level at the same time to simulate HDR viewing condition. The results were used to understand the relationship between the color changes under HDR conditions, to generate a corresponding color dataset and to verify color appearance model, such as CIECAM16.

Influence of scale on the daylighting system evaluation in physical models: Experimental method based on objective and subjective measurements

The daylight evaluation in architectural spaces can be carried out using several tools and methods of investigation and analysis. However, many types of research have proven the usefulness of the scale models to evaluate daylighting system performances in buildings. Several scales of a physical model have been used varying between (1:50) and real scale (1:1), and no comparative study has been done to evaluate the effect of the model size in daylighting assessment. The objective of this investigation is to make a comparison between two different scales of a physical model: the first one is a model with a scale of (1:12) while the second is with the scale of (1: 4), aiming to study the scale effects on daylight perception with models equipped with a daylighting system under very high exterior illuminance levels. The methodology of this study consists in collecting simultaneously the measurement of the exterior and interior illuminance level (lux) and subjective evaluations from a questionnaire survey with the two scale models (1:4 and 1:12) under real sky conditions. A correlation between collected data has been explored. Comparing the measurement results, it is obvious that the quantity of light that penetrates the test models (1:4 and 1:12) was the same. The results are with a range of ±1.6%. Moreover, survey results show that the participants’ perceptions regarding satisfaction, light distribution and glare questions differ with the scale of the physical 3D model. The subjects felt more satisfied with the luminous atmosphere with the physical model of (1:4) compared with the model of (1:12).

DAYLIGHTING APPLICATION SUITABLE FOR ARCHITECTURAL DESIGN WITH LIGHT TUBE IN WAREHOUSES

With the increase in the use of daylight in architecture, providing visual comfort values as well as physical and psychological effects on people and minimizing the lighting energy need of the building have become important in terms of design. Today, with the development of daylight technologies, economic light tubes have become popular in Architecture. Light tubes have become an effective method in Architecture in terms of energy efficiency to illuminate areas of a building that are exposed to limited sunlight. In addition, people prefer to use daylight by nature. Therefore, the use of light tubes continues to increase in buildings with modern architecture. However, due to architectural design and necessities, daylight is used in a limited way in interior areas. While architects determine the position of the light tubes in the building in order for daylight to reach the dark and dim spots of the buildings, knowing the Illuminance level performance of the positioned light tubes has become a necessity for efficient use. In the study conducted to solve this problem, the Daylight Factor Method specified in the European Union EN 17037:2018 Standard was used in the use of light tubes. As stated in the relevant standard, the methods in the daylight factor value ISO 15469:2004 were used. The evaluation of the buildings in terms of daylight performance was calculated in the simulation environment according to the horizontal luminance of the daylight openings. With the designed simulation, the values in the conditions specified in the criteria related to the light tubes are provided. In this way, a light tube that provides energy efficiency is compatible with the circadian rhythm and is compatible with the architecture of this building, and optimum illuminance level values have been determined for the warehouse, which is the subject of the study in the simulation environment.

Partial Daylight Autonomy (DAp): A New Lighting Dynamic Metric to Optimize the Design of Windows for Seasonal Use Spaces

Nowadays, daylight dynamic metrics are the most useful indicators to quantify the use of natural light, with daylight autonomy (DA) being one of the most widespread among all of them. This metric represents the percentage of the occupied time throughout the year in an indoor space when daylight reaches the minimum illuminance level to develop a specific task. Accordingly, the higher the percentage of DA, the shorter the switching on time of electric lighting. However, this metric considers for its calculations all business days of a whole standard year, and is thus not an accurate indicator for seasonal use spaces such as school classrooms. In this context, a variant of this metric is proposed, namely partial daylight autonomy (DAp), which is a non-lineal derivation of DA that considers those seasonal use spaces, helping to define the real percentage of indoor daylight use in order to properly quantify the accurate switching on time of electric lighting and therefore its energy consumption. As deduced from the analysis, the more precise results provided by DAp reach divergences close to 10% in comparison with the original conception of DA. Thus, this metric serves to estimate more accurately the impact on energy consumption if an electric lighting control system is implemented through lux meters. This new proposal has been monitored under real sky conditions in a test cell, providing converging results with those observed in the simulation process.

Methodology Framework for Syaheeza’s Daylight Rule of Thumb for Islamic Religious Schools

Daylight efficiency correlates to window design. Guidelines recommend a 20 per cent window-to-floor ratio (WFR) at 900mm windowsill height, where acceptable 300 lx to 500 lx measured at 900mm working plane height. However, Islamic religious schools use a 300mm height table known as ‘rehal’. Studies neglect the difference in required working plane height that effect window design and the illuminance level. A study was established to propose Syaheeza’s Daylight Rule of Thumb (DRT) for Islamic religious schools. This paper aims to highlight the reliability of the methodology framework used in Syaheeza’s DRT, such as surveys, Arabic handwriting performance assessment and computer simulations. Keywords: Daylighting; Islamic religious school; methodology framework eISSN: 2398-4287© 2021. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians/Africans/Arabians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI:

Ambient light level varies with different locations and environmental conditions: Potential to impact myopia

Purpose Considering that time spent outdoors is protective for myopia, we investigated how ambient light levels reaching the eye varies across 9 outdoor and 4 indoor locations in 5 different environmental conditions. Methods Illuminance (lux) was recorded using a lux meter under conditions of weather (sunny/cloudy), time of a day (7:00,10:00,13:00, and 16:00 hours), seasons (summer/winter), and sun protection (hat and cap) in outdoor and indoor locations. Nine outdoor locations were “open playground”, “under a translucent artificial-shade”, “under a porch facing east”, “under a porch facing south”, “under a big tree”, “between three buildings”, “within 4 buildings”, and “canopy”. As a ninth outdoor location, “Under a glass bowl” in the outdoor location was used as a simulation for “glass classroom model” and measurement was taken at the floor level only to determine in overall the illuminance conditions with glass covered on all sides. The 4 indoor locations included “room with multiple large windows”, “room with combination light source”, “room with multiple artificial lights”, and “room with single artificial light”. Results The overall median illuminance level (median; Q1-Q3) recorded in 9 outdoor locations was 8 times higher than that of all indoor locations (1175;197–5400 lux vs. 179;50–333 lux). Highest illuminance in outdoor locations was recorded in “open playground” (9300;4100–16825 lux), followed by “under a translucent artificial shade (8180;4200–13300 lux) and the lowest in “within 4 buildings” (11;6–20 lux). Illuminance under ‘Canopy’, ‘between three buildings’ and ‘within four buildings’ was similar to that of indoor locations (<1000 lux). Time of the day, weather, season, sensor position and using sun protection did not alter illuminance to change from high to low level (>1000 to <1000 lux). Among indoor locations, illuminance in “room with multiple large windows” crossed 1000 lux at a specific time points on both sunny and cloudy days. Conclusions Illuminance levels in outdoors and indoors varied with location type, but not with other conditions. Given the variation in illuminance in different locations, and the impact it may have on myopia control, appropriate detailed recommendations seems necessary while suggesting time outdoors as an anti-myopia strategy to ensure desired outcomes.

Case Study on the Impact of Artificial Light on Lighting Performance Quality for Architecture Studios

A well-lit learning space is crucial to ensure the comfort of its occupants, especially for an architecture student who spends long hours in a studio to design, sketch, draw and build prototypes. This paper presents the results from a study conducted on the illuminance level of the architecture studios in the city campus of Universiti Tun Hussein Onn Malaysia (UTHM), Malaysia that were once laboratories. Measurements had been done using the Lux meter. Illuminance contours were generated using SigmaPlot and Dialux software for all the five rooms and compared with the requirements stipulated in the Malaysian Standard, Australia/New Zealand Standard and Illumination Engineering Society of North America (IESNA) standard for a room with similar function. A survey was also conducted among undergraduate architecture students who were using the studios daily to gauge their perception on the lighting condition and comfort level. The outcome of this study can be considered for future architecture studio lighting design to improve the students’ learning experience.

The effects of short-term light exposure on subjective affect and comfort are dependent on the lighting time of day

Light, one of the key environmental components for both life and work, played significant role in subjective feelings (e.g. affect and comfort), but the exact effects and mechanisms were still to be determined. The present study screened thirty healthy adults (13 females, 22.45 ± 3.26 years) and examined subjective affect and comfort under short-term white lights with different combination of correlated color temperature (CCT) and illuminance at different times of day (e.g. morning, afternoon, and evening). Our results showed a significant interaction between illuminance level and time-of-day on subjective comfort. Participants felt more comfortable under 50 lx and 100 lx instead of 500 lx in the evening, and more comfortable under 500 lx in the morning and afternoon. In addition, a positive correlation between illuminance and comfort in the morning and a negative correlation between them in the evening were found. No significant effect of CCT on any subjective feeling was revealed. Our results necessitate the consideration of time-of-day in understanding lighting effects and application of healthy lighting in daily life.