• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.2
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• pp.8-17
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• 2012

The objective of this study is to perform an analysis of the heat(heating and cooling) and lighting energy consumption according to the window area ratio and the application of horizontal louver, which is external shading device installed for the purpose of energy savings in office buildings. For this, a building was chosen as a typical example, and the heat and lighting energy consumption was calculated by using the daylight and building energy analysis simulation. The results showed that the total energy consumption, when the lighting control was applied, was reduced by an average of 11.49[%] compared to when there was no lighting control. The smaller the glazing ratio is, the less the total energy consumption is. Also, the application of the horizontal louver increases the total energy consumption under the same condition of glazing ratio.

• Journal of the Korean Institute of Educational Facilities
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• v.9 no.4
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• pp.95-102
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• 2002

The purpose of this study is to renovate a closed school to a artist studio complex applying sustainable principles and methods. Through the case study, the principle and methods of sustainable renovation is investigated and following strategies are extracted as a frame of renovation. First, atrium space with thermal mass using existing wall is proposed as a public gathering space. Second, light shelves for effective lighting and shading device for protecting and allowing sun light is proposed to renovate existing classroom. Third, double skin system is proposed with reflection pool to activate heating and ventilation for passive solar as well as passive cooling. Finally, simulation programs such as energy-10 and Form-Z is used to confirm the validity of the sustainable design.

• KIEAE Journal
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• v.7 no.5
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• pp.41-46
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• 2007

The lightshelf system, a horizontal shading and light redirect device, should improve the visual environment by optimal light distributions and intense illumination levels of a interior. This study aims to evaluate the daylighting performance of window integrated lightshelf systems by computer simulations. For the study, the standard office plan is analyzed through the field surveys. And then, the various lightshelf types attached window systems are picked out from existed research results. The max, minimum and average illuminance levels of interiors and illuminance distributions are evaluated by Lightsacpe 3.2 programs based on the installing height, shape type and moving angle of lightshelfs. As results, it is suggested that the optimum lightshelf shapes are the height 1.8m and the width 600mm. Also, in mixed lightshelf, the outside width 600mm, inside width 400 are efficient on indoor daylighting performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.149-157
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• 2014

This paper is based on the fabrication of wireless control system for the building shading device. RF Module was controlled by UHF wireless CC1020 chip which has low electrical power and low electrical voltage. Also 447.8625~447.9875 frequency, 4800Baud data rate and 12.5 kHz channel spacing was controlled by the use of SPDT switch and with Microcontroller program. Furthermore, the helical antenna was used. The starting production of 447.8625~447.9875 kHz wireless electrical power was used. As the result, it did not exceed 10dBm which is the standard of low power wireless system. Shading efficiency was measured at 25%, 50%, 75% direction with controlling the interior temperature and the intensity of illumination at the rate of 1 hour. As the result, the intensity of illumination was lowered to 82~87% at 25% direction with $0.6{\sim}1.4^{\circ}C$ lowered temperature. At 50% direction, the intensity of illumination was lowered to 60~68% with $2.3{\sim}4.1^{\circ}C$ lowered temperature. And at 75% direction, the intensity of illumination was lowered to 41~47% with $3.4{\sim}5.1^{\circ}C$ lowered temperature.

• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.169-174
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• 2007

Building integrated photovoltaic(BIPV) system operates as a multi-functional building construction material. They not only produce electricity, but also are building integral components such as facade, roof, window and shading device. As PV modules function like building envelope in BIPV, combined thermal and PV performance should be simultaneously evaluated. This study is to establish basic Information for designing effective BIPV by discovering relations between temperature and generation capability through experiment when the PV module is used as roof material for houses. To do so, we established 3kW full scale mock-up model with real size house and attached an PV array by cutting in half. This is to assess temperature influence depending on whether there is a ventilation on the rear side of PV module or not.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.817-822
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• 2000

A proper flashing light is expected to enhance microalgal biomass productivity and photosynthetic efficiency. The effect of flashing light on high-density Chlorella kessleri (UTEX 398) cultures was studied using light-emitting diodes. A frequency modulator was designed to flash LEDs, and the device successfully provided wide range of frequencies and various duty cycles of flashing. A relatively high frequencies of 10, 20 and 50 kHz were used in this study. These frequencies have very short flashing time ($2-50{\mu}s$), which corresponded to the time constant of the light reaction of photosynthesis. The specific oxygen production rates of photosynthesis under flashing light were compared with those under an equivalent continuous light in specially designed illumination cuvette. The specific oxygen production rates under flashing light were 5-25% higher than those under the continuous light. A range of cell concentration was discovered, where the benefit of flashing light was maximized. The photosynthetic efficiency was also higher under flashing light with frequencies of over 1 kHz, which was a clear indication of flashing light effect and the degree of mutual shading could by overcome by flashing lights, particularly at high-density algal cultures.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.43-48
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• 2009

In this study, through case studies, solar energy systems were coordinated with architectural plan elements and the others in apartment complex, and the energy performance was evaluated quantitatively through computer simulation PVSYST and RETScreen. As a results, in plan process of the application of solar energy systems in apartment complex, solar energy system should be considered as not only energy reducing technical element but also part of architectural plan element. And it must be considered with architectural plan elements, composition methods, energy storage methods, technical elements from the early basic plan stage. Photovoltaic system was installed on the wall facing the south and rooftop. The energy ratio of electric load was shown to be 5.5%. The result showed 7.2% when adding it to shading device additionally, and 6.4% in case of putting extra translucent module on windows. Active solar collecting system was applied on roof with the angle of 45. Maximum number of solar collector was 10 in a row, and the total solar collecting area was $915.00m^2$. The energy ratio of domestic water heating load by active solar hot water system is shown to be 11.4%.

• KIEAE Journal
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• v.16 no.5
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• pp.21-28
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• 2016

Purpose: The Objective of this study is to explore the capabilities of an integrated modelling and simulation workflow when applied to an experiment-based research process, aimed at deriving daylight optimization strategies specific to tall buildings. Methods: Two methods were devised to apply this workflow with the help of DIVA and Rhino/Grasshopper. The first method is a multiple variant analysis by setting up an appropriate base case and analysing its daylight and energy performance, forming the basis of comparison for subsequent cases for design variants. The second method involved setting up the base case within a site context and conducting a solar irradiation study. An architectural variables such as overhang and shading device, were then defined as inputs in the parametric definition in Grasshopper to control the selected variable. Results: While the first method took advantage of the speed and efficiency of the integrated workflow, the second method was derived based on the ability to directly process simulation data within the integrated, single-software platform of the proposed workflow. Through these methods, different architectural strategies were explored, both to increase daylight penetration and to reduce radiant heat gain. The focus is on methods by which this workflow can be applied to facilitate the experimental derivation of daylight optimization strategies that are specific to tall building design.

• KIEAE Journal
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• v.17 no.3
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• pp.99-106
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• 2017

Purpose: Most modern office buildings adopt the curtain wall system in order to provide occupants with the sense of openness and high-technology, which requires large window area. As a result, the amount of solar radiation increases, negatively affecting cooling load during the summer and increasing energy costs. However, the performance of window itself is not sufficiently controllable parameter to control thermal comfort and solar radiation. Therefore, a shading device such as venetian blind is required to control them and thus a variety of studies have been performed thus far. So, the purpose of this study is to improve the performance of blind through the development of blind control algorithm. Method: Among various input variables for the control of venetian blinds, the vertical solar radiation has been selected in this study as the primary input variable and the optimal control algorithm for venetian blinds were developed for each window orientation. Result: The developed optimal control algorithm has a positive effect on building energy savings.

• Journal of the Korean Solar Energy Society
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• v.33 no.2
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• pp.84-92
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• 2013

Blinds are a common type of shading device and are increasingly operated automatically to overcome the limitations of manual operation. Automated blinds need to be controlled to maximize benefits of daylight in the point of occupant comfort and energy consumption. However, the previous control methods could cause occupant's distractions by the undesirable control time interval and amount of blind movement. A few researches suggested the control concept for minimizing occupant's distractions by automatic blind control, but they did not provide optimal control algorithm to be useful in practice. In this paper, we propose an optimal control algorithm for automated blinds that can maximize not only visual comfort but also sunlight penetration into buildings based on occupants' preferences on blind movement and sunlight. The proposed control algorithm can prevent solar glare on workplane and minimize occupant's distractions to maximize occupants' visual comfort.