주거공간 내 사용자인식기술 적용 조명에너지 저감 광선반 시스템 연구

서태원(Seo, Tae-Won),이행우(Lee, Haeng-Woo),김용성(Kim, Yong-Seong) 대한건축학회 2012 대한건축학회논문집 Vol.28 No.11

The current energy consumption of buildings occupies 23.5% of the total energy consumption in Korea, a high ratio, of which about 22% is consumed through lighting energy. For that reason, various experiments and research have been undertaken to reduce the energy consumption needs of indoor artificial lighting. This study suggests a light-shelf system applied with user recognized technology based on considerations of the light-shelf system and user recognized technology, and verified the possibility of introducing it to residences, and its effectiveness by comparing the results of energy reduction performance evaluations for the proposed light-shelf system with the user recognized technology and that with user unrecognized technology. The light-shelf system applying user recognized technology is a system that allows the occupant to set the luminance value of the room so that the light-shelf system and lighting can be interlocked and provide the luminance value requested by the occupant. In order to verify the energy reduction effects of the light-shelf system with the user recognized technology applied, this study has calculated the power consumption of lighting energy for a user unrecognized fixed light-shelf system, a user recognized fixed light-shelf system and a user recognized variable light-shelf system. From the results, when comparing the user unrecognized fixed light-shelf system and the user recognized fixed light-shelf system, Case A did not generate a reduction in energy consumption, and Case B saw a 4.4% reduction of lighting energy consumption levels. Case C generated a 13.3% reduction of lighting energy consumption. When comparing the user recognized fixed light-shelf system and the user recognized variable light-shelf system, power consumption was equivalent in Case A of one occupant and A, B and A, Case C for 2 occupants, while a 13.3% energy reduction was achieved for Case B of 1 occupant and B, Case C of 2 occupants. Case C of 1 occupant also achieved a 15.2% lighting energy consumption reduction. The user recognized variable light-shelf system showed the largest reduction of lighting energy power consumption, followed by the user recognized fixed light-shelf system and the user unrecognized light-shelf system in order of the reduction of lighting energy power consumption from user recognition.

실내공간 깊이와 광선반 규격 변화에 의한 광선반 성능평가 시뮬레이션 연구

이행우(Lee, Heang-Woo),김덕수(Kim, Duk-Su),김용성(Kim, Yong-Seong) 대한건축학회 2013 대한건축학회논문집 Vol.29 No.3

There are so much of researches underway in order to find out the solution to 22% higher lighting energy consumed by a building. In particular, many studies on light shelves are ongoing due to the merits such as guiding light inflow into deep inside a building as well as allowing excessive shading. The existing literatures fail to provide adequate basis in designing light shelves for various sized space, as they are limited only to performance evaluation on variables of light shelves. In this study, performance evaluation on light shelves was performed by dividing space depth at the interval of 1m for 3~8m, to draw a conclusion as follows: 1)First, the analysis resulted in 6m, 4m and 3m of space depth that entirely meets standard intensity of illumination 400lux, with light shelves not installed for Winter Solstice, Summer Solstice and Spring/Autumnal Equinox Day, while it showed 4∼6m, 3∼4m and 3∼4m with light shelves installed in depth and at angle as specified by this study, telling us there was no Daylighting Efficiency by changes in space depth except Summer Solstice even with light shelves installed. 2)The performance of light shelves depended on, in order, the specular surface of light shelves, the reflection of ceiling and the position of third reflection to be changed by space depth which have to be considered as an element in designing. Especially in the cases of at the angle of 20° during Winter Solstice and angle of 30° during Spring/Autumnal Equinox Day, extra care should be paid while designing a light shelf that will directly guide light inflow to indoor through its specular surface. 3)As the depth of light shelf increased, the shade size caused by light shelfrose along with higher uniformity ratio of illuminance, while it reduced with less uniformity ratio of illuminance as the angle of light shelf increased. 4)Considering the space depth set by this study, light inflow and reflection type through light shelf and uniformity ratio of illuminance, the adequate proposals were drawn as an external light shelf of 10° and 0.3m in depth, an external light shelf of 20° and 0.3m in depth, and an external light shelf of 30° and 1.2m in depth, for Winter Solstice, Spring/Autumnal Equinox Day, and Summer Solstice, respectively. However, for Summer Solstice, it was determined that the most appropriate proposal was an external light shelf of 0.3m in depth, considering the fact that an external light shelf with the angle of 30° is efficient in general and that the angle of a light shelf is changed by operation. This study provides meaningful performance evaluation on light shelf by space depth. Further multilateral studies will be required in consideration of the height and the depth of space as the element of space size.

반사판의 폭 조절이 가능한 서랍형 타입의 가동형 광선반 개발 연구

김다솜(Dasom Kim),이행우(Haengwoo Lee),서장후(Janghoo Seo),김용성(Yongseong Kim) 대한설비공학회 2016 설비공학 논문집 Vol.28 No.9

Due to the recent increase in lighting energy consumption in buildings, there are a growing number of studies seeking solutions this problem. The effectiveness of light-shelves as natural lighting systems to solve this problem has been recognized, and various studies regarding such systems are being carried out currently. However, the lighting efficiency of light-shelves decreases if illumination intensity is low-such as at night time, and it also obstructs the views of building occupants. Therefore, the purpose of this study is to examine a movable drawer type light-shelf which allows for the width of the reflector to be adjusted and verify its performance through a simulated test-bed. The following conclusions were reached. 1) The purpose of this study is to solve the problem previously associated with the light-shelf system- of obstructed views-by responding to external environments and minimizing the width of the light-shelf at night time when the efficiency of the light-shelf declines. 2) The proper variables of the movable drawer type light-shelf which enables the width adjustment of the reflector were ascertained in this study according to four solar terms : a width of 0.6 m at an angle of 20°, a width of 0.4m with an angle of 20°, and a width of 0.1 m with an angle of 20° were determined for the summer solstice, fall/spring equinoxes, and winter solstice respectively; revealing that width adjustment of the light-shelf is a significant factor. 3) The movable drawer type light-shelf which enables\width adjustment of the reflector suggested in this study can reduce the lighting energy consumption by 18.7% and 14.3% in comparison to previous light-shelves with a fixed width of 0.3 m and 0.6m, indicating that it is effective for saving energy.

주거공간 내 광선반 곡률 형태에 따른 채광성능평가 연구

오상원(Sangwon Oh),이행우(Heangwoo Lee),김용성(Yongseong Kim),서장후(Janghoo Seo) 대한설비공학회 2015 설비공학 논문집 Vol.27 No.6

Currently, 22% of the total energy consumption of buildings in Korea is used for lighting. Light-shelves have garnered attention as a way to reduce consumption, but there are few studies on the types of curve and curvature, which limits the improvement of light-shelf performance and its design. This study constructed a test bed of actual residential types to evaluate the performance. Outcomes of light usage, according to variables of light-shelves, were used as indicators of performance evaluation. The results are as follows:1) Performance evaluation was conducted on flat-type light-shelves to verify performance of curvature-shelves, which are movable with a width of 200 mm, and the most ideal angle and specification per solar term are calculated. 2) The (-) shaped curvature contributed to a reduction in energy consumption and an improvement of evenness. 3) In case of light-shelves with (-) shaped curvature, an increased angle not exceeding 80° of the arc contributed to an improvement of light penetration. 4) Appropriate specifications of curved light-shelves include movable types with widths of 200 mm, and angle ranges of 20˚~60˚. 5) Light energy consumption of a movable light-shelf with curvature and width of 200 mm were reduced by 17% and 7.8% compared to a 0˚ fixed and a movable light-shelf, respectively.

천장의 기하학적 형태에 따른 광선반 성능평가 시뮬레이션 연구

이행우(Henagwoo Lee),김용성(Yongseong Kim),서장후(Janghoo Seo),김덕수(Duk-Su Kim) 대한설비공학회 2014 설비공학 논문집 Vol.26 No.4

Light-shelf is one of the most efficient natural lighting systems due to the improved function of the inflow level of the outdoor natural light. However, the existing research on the light shelf limits to the rectangular parallelepiped space, so do not provide sufficient data for various shapes of spaces. Thus, this study aims at deriving proper plan and relationship of the light shelf through its performance assessment depending on the indoor space shapes and utilizing them as basic data of light shelf design. The conclusions are as follows:1) for 6m space depth, standard intensity of illumination satisfaction depth has shown 8.3%~26.3% improvement through the adjustment of the angle and width when installing light shelf compared to no light shelf installation; 2) -30˚, -20˚ and -10˚ light shelves set by this study play only as a blind regardless of the shape of ceiling on the summer solstice, and it is unsuitable; and 3) this study has derived proper plan of light shelf upon space shapes based on energy reduction and indoor evenness. The study results provide expanded data of the performance assessment of the light shelves according to the different space shapes and light shelf factors, which serves as a basis of the light shelves designing.

실내 공간의 반사율에 따른 광선반 성능평가 연구

전강민,이행우,김용성 사단법인 인문사회과학기술융합학회 2015 예술인문사회융합멀티미디어논문지 Vol.5 No.5

There has been a significant increase in the amount of research on reducing the lighting power consumption of buildings and also an increasing demand for technological development. Light shelf has been recognized as one of the most efficient solutions to this issue and related researches have been conducted, which have mostly focused on factors related to simple light shelves and are not suitable as an appropriate basis for the design of light shelves. Thus this study aims to establish the proper design basis for light shelves by evaluating the performance of shelves per reflection rate in indoor areas. Power consumption rate and indoor illumination intensity distribution of a testbed built based on actual living conditions were calculated for the performance evaluation, of which the results are as following: 1) Reduction of reflection rate of ceiling and walls caused average illumination intensity in summer, winter and median seasons, and evenness per reflection rate of indoor areas was found to be different in summer, winter and median seasons, making it a necessary consideration for designing light shelves. 2) Calculation of power consumption from lighting control showed that a high reflection rate of indoor areas may be suitable for power consumption reduction, and that reflection rates higher than 80% for ceilings and higher than 75% for walls in terms of the efficiency of researches on the indoor reflection rate and its application would be appropriate. This study is meaningful as the research focuses on light shelves based on considering indoor environmental factors. More studies will be required that consider a variety of factors. 최근 건물부분에서의 조명에너지 증가로 인한 이를 해결하고자 하는 연구와 기술기발의 수요는 증가하고 있으며, 광선반은 이러한 문제에 대한 해결책 중 하나로 그 유효성을 인정받아서 많은 연구가 이루어지고 있다. 그러나 광선반에 관련한 연구는 단순 광선반의 변인에 초점에 맞추어져 광선반 설계시 적절한 설계기초자료가 될 수 없다. 이에 본 연구는 실내공간의 반사율에 따른 광선반 성능평가로 광선반 설계시 기초자료 구축을 목적으로 한다. 본 연구는 실스케일의 테스트베드를 통하여 실내 조도 분포 및 조명에너지 사용량을 산출하여 성능평가를 진행하였으며, 이에 대한 결론은 다음과 같다. 1) 실내공간의 천장과 벽의 반사율 감소는 동지, 하지, 중간기시 모두 평균조도를 감소시켜 조명에너지 저감에 부적합하며, 실내공간의 반사율에 따른 균제도는 동지, 하지, 중간기시 상이한 경향을 보여 광선반 설계시 고려해야 할 요소로 판단된다. 2) 조명제어에 따른 전력사용량을 도출한 결과 실내 공간의 높은 반사율은 에너지 저감에 적합할 수 있으나 실내 공간의 반사율에 관련한 연구 및 적용의 효용성에 입각하여 천정 80%이상, 벽면 75%의 반사율이 적정할 것으로 도출된다. 본 연구는 실내 환경의 변인을 고려한 광선반 연구로 의미를 부여할 수 있으며, 향후 보다 다각적인 변인을 기반한 연구는 지속적으로 필요할 것으로 판단된다.

결정면 적용 광선반 채광성능 평가 연구

이행우(Heangwoo Lee),Kyle Eric Rogers,서장후(Janghoo Seo),김용성(Yongseong Kim) 대한설비공학회 2015 설비공학 논문집 Vol.27 No.8

Recently, many research studies have been carried out on the efficiency of light-shelf daylighting systems, especially comparing performance improvements and the limitations of reflective surfaces and their lighting performance. In this study, a crystal face reflective surface is proposed. The objective of the study is to evaluate the lighting performance of a crystal face light-shelf through a performance study. The performance study was carried out in a full scale test-bed in order to calculate the light distribution and energy consumption utilizing the standard indoor illumination as an index. The conclusions of the performance study are as follows. 1) The optimal angle of incidence for daylighting for both the operable flat type light-shelf and the crystal face light-shelf are taken in the natural environment on the dates of the winter and summer solstices, as well as the autumn and spring equinoxes. 2) The application and installation of the crystal face light-shelf can produce a 29.9%~34.3% increase of light distribution within the indoor space. However, the increase of light distribution can also lead to a decrease in the uniformity ratio, a design challenge that should be considered when applying a crystal face light-shelf. 3) It is possible to achieve a 7.98%~13.3% greater reduction in energy consumption when applying a crystal face light-shelf than when applying a flat type light-shelf. The increase in the number of crystal faces should concur with the analysis of the energy reduction. A limitation of the study is that only one predetermined pattern was performance tested for a crystal face light-shelf. In order to carry out further research on crystal face light-shelves, additional performance studies are needed based on alternative patterns and designs.

주거공간 내 사용자인식기술 및 조명 디밍제어 적용 광선반 시스템 성능평가 연구

권순현(Kwon, Sun-Hyeon),이행우(Lee, Heang-Woo),서장후(Seo, Jang-Hoo),김용성(Kim, Yong-Seong) 대한건축학회 2014 대한건축학회논문집 Vol.30 No.2

The energy used by buildings occupies 38% of the entire energy usage in Korea, of which lighting consumes 22% in considerable amount. Accordingly, various tests and researches to reduce energy consumed by buildings, especially consumption of indoor lighting energy have been constantly carried out. This study has suggested a light shelf system applied with user awareness technology and lighting dimming control system on the basis of light shelf system, user awareness technology and lighting control, and verified energy reduction efficiency by comparing results of energy reduction performance evaluation for the suggested light shelf. In order to verify energy reduction of the suggested system, a test bed has been utilized, energy consumptions have been calculated for 3 types including user unawareness and lighting On/Off control light shelf system, user awareness and lighting On/Off control light shelf system, user awareness and lighting dimming control light shelf system, and users have been set to User A, User B, and User C for family members of 60s, 40s, and 10s. The results are shown below. 1) Lighting energy consumption for user awareness technology and lighting On/Off control applied movable type light shelf system showed 105%, 55%, and 20% for User A, User B, and User C comparing to user unawareness and lighting On/Off control applied 0˚ fixed light shelf system and in the case of User A, it has increased energy usage and is inappropriate. 2) Lighting energy consumption for user awareness technology and lighting dimming control applied movable type light shelf system showed %, 13%, and 6% for User A, User B, and User C comparing to user unawareness and lighting On/Off control applied 0˚ fixed light shelf system, and allowed efficient energy reduction. This study is significant from an aspect that it has suggested an alternative to energy shortage problem by applying user awareness technology and lighting control technology and verifying effectiveness of energy reduction in order to improve lighting performance and energy efficiency of the light shelf.

PV 부착 광선반의 채광성능 및 에너지 저감 기초 연구

김정민(Jeong Min Kim),이행우(Heang Woo Lee),서장후(Jang Hoo Seo),김용성(Yong Seong Kim) 대한설비공학회 2018 설비공학 논문집 Vol.30 No.8

Because of the recent increase in energy consumption in the building sector, more studies are being conducted to address this issue. As a part of this research, some studies have focused on solving the building-energy problem by combining the PV and light shelf, whereas previous studies examined the role of the PV by attaching it to the front of the reflector. Therefore, the purpose of this study is to derive the optimal specifications for the light shelf with PV by carrying out a performance evaluation of the lighting energy reduction and concentration according to the PV attachment area of the light shelf. This study established a full-scale test bed and an artificial light environment in order to prove the effectiveness of building-energy reduction by deriving the lighting-energy consumption and concentration energy according to the PV attachment area and light-shelf angle. The conclusions are as follows. (1) The optimal light-shelf angle to reduce the lighting energy for the conventional light shelf without PV was 30° for summer and -10° for winter. (2) The optimal light-shelf angle to increase the concentration efficiency of the light shelf with PV was -10° for summer and -60° for winter. (3) The light-shelf variables to reduce its lighting energy with PV and to increase the concentration efficiency of the PV were derived. Given the optimal variables thus derived, the light shelf with PV reduced building energy between 23.7 and 58.1 percent more than did the light shelf without PV, which proves its effectiveness.

조명해석 프로그램을 이용한 광선반의 채광성능분석에 관한 연구

조일식(Cho Yil Sik),김병수(Kim Byoung Soo) 한국태양에너지학회 2007 한국태양에너지학회 학술대회논문집 Vol.- No.-

The purpose of this paper is to make an optimum guideline of a light shelf suitable for the domestic situation, this study is worked by experiments using a light shelf and analysis of variables(light self length, reflectance, angle of a light shelf and domestic position) using illumination program(Lightscape). The result of this study is summarized as follows. 1) Concerning the presence of a light shelf itself, the ratio of the maximum to the minimum inner illuminance and the proportion of inner daylight decrease 3.5 times as much as that, whereas a distribution of inner illuminance is uniformed 2) Concerning the Sky conditions, the a light shelf has little effect on the light in the overcast sky, whereas it has an effect on the light in the partial overcast sky with the over 45,000lux and in the clear sky with the over 75,000lux. Especially, in the partial overcast, a light shelf was in the highest of efficiency. 3) Concerning the degree of angle of the a light shelf, there is no change under 10 degree from the horizon, whereas the uniformity ratio of inner illuminance and the proportion of inner daylight increase respectively 48% and 29% between 20 and 30 degree. The latter condition is proved to be better for an uniformed distribution of inner illuminance and a more effective lighting. 4) Concerning the proportion of reflectance of a light shelf, 10% of increase each ranging from 60% to 90% is proved to have no effect on the increase of light. 5)The inner and outer optimum size of a light shelf is proved to be over 200㎜ and 600㎜ respectively, which makes it possible to make a general formula adaptable to all parts of our country.