• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.11
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• pp.788-797
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• 2010

This study examines the influence of fluctuating daylight illuminance on daylight dimming control systems. Field measurements were performed for a full-scale mocked-up model under various daylight conditions in winter. Fluctuating ranges for a partially-shielded photosensor were great when the variation of sky ratio was great. When solar altitude was lower the illuminance and fluctuating range of illuminance were great due to the influence of direct components of daylight and the interrefelction between surfaces in rear area of space. It implies that daylight dimming system would not function effectively, unless the desktop illuminance by daylight is enough. Fluctuation ranges of photosensor illuminance were lower than 50 lx under clear sky conditions, but they were greater than 100 lx under partly-cloudy sky conditions. It means that the fluctuation range of electric light output of lighting fixture would greater under the partly-cloudy conditions and cause potential visual annoyance to occupants. Outdoor vertical illuminance reaching the windows would be an effective factor that can be used to predict the fluctuation of photosensor signals for effective controls of daylight dimming system.

• Journal of the Korean Solar Energy Society
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• v.36 no.6
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• pp.37-46
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• 2016

In this study, long-term global illuminance data for 19 selected cities are calculated from modeled solar radiation data, AEER's TMY2. Perez model in Daysim daylight simulation tool is used for the solar radiation to illuminance conversion. And then, daylight availability in an unit office space is evaluated for the 19 cities. For this evaluation, various daylight performance indices are reviewed since static daylight performance index such as daylight factor (DF) and annual average global illuminance value is not suitable for actual performance evaluation in terms of visual comfort and light energy saving of a space. This study evaluated daylighting performance of prototypical office space module by introducing DA (daylight autonomy) and UDI (Useful Daylight Illuminance) index for major cities of Korea. Result shows that there is upto 18% of illuminance level difference with annual average global illuminance data, but if we consider useful daylight in a space the illuminance level difference among the cities are only within 5%. This means that for sustainable building design especially in daylight design, amount of annual global illuminance is not important factor even in cloudy cities. Daylight design and daylight harvesting system would return similar energy saving impact regardless of building location.

• Land and Housing Review
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• v.10 no.3
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• pp.33-41
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• 2019

This study examines the distributions of daylight illuminance in a small office space under clear and cloudy sky conditions. Three shading conditions using Venetian blinds were applied for the analysis of daylight illuminance. Computer simulations using the Lightscacpe were conducted for the daylight conditions applied to the office space. Results indicate that the illuminance differences between clear and cloudy sky for south-facing conditions were greater than those for north-facing conditions. The differences in December and June were the greatest and smallest, respectively. For the north-facing conditions, the daylight illuminance at 10:00, 12:00 and 14:00 in June and September under the cloudy sky was higher than those under the clear sky conditions. For all daylight conditions, the biggest amount of illuminance reduction occurred when the shading device conditions were changed from the no blind to the 45 degree blinds. As the distance from window increased, the shading effect that occurred when the shading device conditions were changed from the horizontal blind to the 45 degree blinds increased.

• KIEAE Journal
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• v.11 no.1
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• pp.47-55
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• 2011

Daylight is highly beneficial for improving the indoor environmental quality and reducing building energy consumption, daylighting applications are scarcely considered, especially during the Rural standard house models design process, because of lack of previous studies on elderly-light environment and complex simulation process. Therefore, daylighting process were performed using ECOTECT, which has various advantage such as easy user interface and simple simulation processes. Moreover, dynamic daylight simulation were performed using whether data. Static simulation are performed to compute static metrics such as daylight factor, whereas dynamic simulation are performed for dynamic metrics such as daylight autonomy and useful daylight illuminance using annual weather data On the basis of daylight autonomy and useful daylight illuminance analysis result, variations in annual daylight performances. A parametric and regression analysis of the window-to-wall ratio and visible transmittance showed that daylight factor, daylight autonomy increased with window-to-wall ratio and visible transmittance. It can be concluded that this new daylight criteria. useful daylight illuminance, will enable architect to obtain better fenestration design.

• Journal of The Korea Institute of Healthcare Architecture
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• v.17 no.1
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• pp.33-40
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• 2011

Daylight is highly beneficial for improving the indoor environmental quality and reducing building energy consumption, daylighting applications are scarcely considered, especially during the care facility design process, because of lack of previous studies on elderly- light environment and complex simulation process. Therefore, daylighting process were performed using ECOTECT, which has various advantage such as easy user interface and simple simulation processes. Moreover, dynamic daylight simulation were performed using whether data. Static simulation are performed to compute static metrics such as daylight factor, whereas dynamic simulation are performed for dynamic metrics such as daylight autonomy and useful daylight illuminance using annual weather data On the basis of daylight autonomy and useful daylight illuminance analysis result, variations in annual daylight performances. A parametric and regression analysis of the window-to-wall ratio and visible transmittance showed that daylight factor, daylight autonomy increased with window-to-wall ratio and visible transmittance. It can be concluded that this new daylight criteria. useful daylight illuminance, will enable architect to obtain better fenestration design.

• KIEAE Journal
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• v.10 no.6
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• pp.41-46
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• 2010

This study is to validate the K University daylight measurement system according to the CIE guide of recommended practice of daylight measurement. In this study global irradiance, illuminance, direct normal illuminance, diffuse irradiance, illuminance and vertical illuminances(North, West, South, East) were measured and compared in accordance with the CIE quality control test. Field monitoring was conducted from 1st August to 15th August 2010. Results for the CIE tests 1 to 4 showed an accuracy of 100%. This indicates that the K University daylight measurement system is reliable and the measurement data would be useful for further daylight researches.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.3
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• pp.231-242
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• 2011

This study examines influences of a daylight dimming control system on the variation of indoor illuminance and lighting energy savings in a small office space. Field measurements and a series of computation were performed for typical types of sky conditions in summer. Results indicate that the daylight illuminance under clear and partly-cloudy sky were close to the target illuminance during a majority of time due to a higher ratio of window to wall. However, the target illuminance was not kept successfully due to the variation of photosensor signals which were strongly influenced by desktop illuminance. The system with partially-shielded conditions succeeded to keep target illuminance under clear sky conditions. The system failed under overcast sky conditions since the electric light output from fixtures caused excessive signals to photosensors due to insufficient daylight on a desktop. Unshielded and fully-shielded conditions were not recommended for effective controls of the systems. The influence of lighting fixtures on photosensors should be minimized to achieve successful lighting controls by daylight dimming systems.

• Journal of the Korean Solar Energy Society
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• v.26 no.3
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• pp.33-43
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• 2006

Daylight dimming control system was analyzed for an indirect lighting system in a small office space with a double skin envelope system. Computer simulations were performed for photosensors with three shielding conditions. The photosensors were placed on the center of ceiling, and backwall. Three sky conditions defined by CIE were considered. Overall, control performance was not very excellent for all conditions. Fully-shielded photosensor achieved good control performance for some cases, but partially-shielded and unshielded photosensors failed to achieve target illuminance. The variation in desktop illuminance due to daylight was examined for a variety of daylight conditions. Linear correlation between desktop illuminance and photosensor illuminance was analyzed using ANOVA.

• Journal of the Korean Solar Energy Society
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• v.28 no.6
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• pp.78-86
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• 2008

The aim of this paper is to show the daylight environment of a light pipe system according to sun movement. A light pipe system has been mounted on the roof of the windowless full scale model: the solar spot has diameter of 0.65m and is 1.3m long, giving an aspect ratio of 1:2. The full scale model was installed on the rooftop of the SHINAN apartment in Yongin city that has no obstructions against sunlight. The test room is equipped with sensors for the measurements of the internal illuminance and has an area of 6m(W)$\times$6m(D)$\times$4m(H). The system has been monitored with a data-logger to evaluate the cumulative distribution of illuminance on a floor-plane from 16th, April to 29th, May, 2008 over one month and selected clear sky condition. For the daylight performance of floor area, the totally 49 measuring points has been used to determine the internal illuminance and an HP datalogger(HP34970A) records the measurements for one consecutive month. The horizontal external illuminance has been measured with two outdoor sensors. This paper presents the results of monitoring light pipe system with internal/external illuminance ratio and cumulative frequency distribution of floor-plane illuminance are discussed The results show that lightpipe is proficient device for introducing daylight into the building. However It provided different daylight indoor environment with wide or narrow Interquatile range of illuminance, internal/external illuminance ratio and cumulative frequency distribution according to solar positions under suuny sky condition. For more achieving the improvement of lightpipes also include energy savings, user visual comfort with various indicators; seasonal solar height, room and lightpipes geometries.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05b
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• pp.99-104
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• 2011

Daylighting system is an alternative to the energy crisis and environment change. And it is possible improvement system of Architectural Space Environment. Accordingly, it is very useful system. Because Daylight Duct System of Daylighting System gives high performance for its price, distribution rate is very high. But Daylighting Duct System is hard to accurate control. Accordingly, it is difficult to maintain continuously Daylight Environment in Interior Spaces. Lighting Diffusion System has been developed that it is Applying the principle of Reflector and prism diffuser for maximize the efficiency of lighting of Daylight Duct Systems through this study. And then compare lighting performance of Existing System and new Lighting Diffusion System through producing a mock-up. Thus, this study was carried out for the purpose of verification for excellence. It is that installed Each Daylighting Duct System for performance evaluation in a laboratory of width 4m, length 10m, height 2.5m. And illuminance was measured at noon on winter solstice(December 22) under clean sky. The actual measurement result was in the following. Newly developed lighting Diffusion system was measured maximum illuminance 399, minimum illuminance 221, average illuminance 141. Synthetically, daylight factor, uniformity factor and illuminance distribution were improved more than existing system. As a result, it was confirmed that was improved lighting Environment in Interior Spaces.