• Biotechnology and Bioprocess Engineering:BBE
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• 제4권1호
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• pp.78-81
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• 1999

Light penetration depth in high-density Chlorella cultures can be successfully estimated by Beer-Lambert's law. The efficiency of light energy absorption algal cultures was so high that algal cells near the illuminating surface shade the cells deep in the culture. To exploit the potential of high-density algal cultures, this mutual shading should be eliminated or minimized. However, providing more light energy will not ease the situation and it will simply drop the overall light utilization efficiency.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.189-192
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• 2000

광합성 홍색세균의 light harvesting complex II (LHC II)발현 유전자가 제거된 돌연변이종을 halogen 램프 하에서 거리에 따라 광도를 달리하며 배양하여 wild type과 생산성을 비교한 결과 낮은 광도(34 ${\mu}E/m^2/s$)에서는 wild type가 높은 광도 (376, 118 ${\mu}E/m^2/s$)에서는 mutant가 높은 세포농도를 나타내었다. 특히 118 ${\mu}E/m^2/s$에서 LHC $II^-$ mutant가 56% 높은 세포생산량을 보였다. 이는 세포내 pigment양의 감소로 mutual shading effect가 감소하였기 때문으로 판단되었다.

• 한국태양에너지학회 논문집
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• 제27권1호
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• pp.91-98
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• 2007

Perimeter zone is one of the weakest area in buildings and it makes an increase of heating and cooling loads, in addition to condensation or discomfort with cold-draft to residents in winter. Because of this, it needs to be reinforced by active systems. However, they use fossil fuel, and ultimately greenhouse effect is urged. Thus, we proposed BIPV system functioned as solar collector which can substitute active system. As an fundamental stage, heat balance equation in steady-state by Fortran was used not only, in winter for pre-heating effect and electric power capacity during the day, but also in summer, for the latter during the day and sky radiation effect during the night. Especially, we should have considered shading on PV by IES Suncast, since even a little bit of it makes the efficiency too low for the PV modules to work. As a result, in summer day, the PV panel should be tiled in 70 degrees to gain the most electric power. Moreover, we could verify that this model makes higher temperature and heat flux under 0.02 m/s. On the other hand, the PV had the high efficiency with high velocity because of cooling effect behind the PV. Therefore, we should regard the air current distribution later on.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.125-130
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• 2007

The aim of this study is to discover the possibility as the shading systems, and to analyze daylight distribution and characteristic of light on the Korean traditional paper. Korean traditional paper has a good efficiency to diffuse the light and is less glare than Roller Shade fabric. In the president office buildings and apartment houses, daylight characteristic of Korean traditional paper windows could be used as a preliminary data to develop a window system which makes greatest performance of daylight.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.75-80
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• 2008

Recently, Energy savings in buildings has received much attention in response to the increased needs for global warming and better comforts of the occupants in apartment housing. This study proposes the method which uses the sun control window film to reduce the cooling load and heating load improving the thermal performance of the building and it improves an energy efficiency. The film which used in actual measurement has a low shading coefficient and a solar energy transmission. so we measured the surface temperature of the triple Low-e glazing system used and inside temperature according to the change of outside temperature and solar energy to study thermal performance evaluation. As a result, it was helpful to use window film insulation to reduce inside temperature in summer and to keep room warm in winter.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.85-88
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• 2008

The purpose of this study is to analyze daylight distribution and light characteristics on the Ma-ji and Roller Shade fabric, and to investigate a possibility of using it as a shading system. Using a 1/2 Mock-up model, daylight distribution is analyzed with the Ma-ji and Sun-ji (Korean traditional paper) which have good efficiency and less glare. Ma-ji has the best daylight distribution, so that daylight experiment is conducted with the Ma-ji and Roller Shade fabric. In current office buildings and apartment houses, daylight characteristics of Korean traditional paper windows could be used as preliminary data to develop a window system which makes better daylight performance.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권3호
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• pp.186-190
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• 2000

It has been reported that flashing light enhances microalgal biomass productivity and overall photosynthetic efficiency. The algal growth kinetics and oxygen production rates under flashing light with various flashing frequencies (5Hz-37 kHz) were compared with those under equivalent continuous light in photobioreactors. A positive flashing light effect was observed with flashing frequencies over 1kHz. The oxygen production rate under conditions of flashing light was slightly higher than that under continuius ligth. The cells under the hight, particularly at higher cell concentrations. When 37kHz flashing light was applied to an LED-based photobioreactor, the concentration was higher than that obtained under continuous light by about 20%. Flashing light may be a reasonable solution to overcome mutual shading, particularly in high-density algal cultures.

• 한국조경학회지
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• 제33권6호
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• pp.98-108
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• 2006

The climate of urban area is an unstable type with considerable seasonal variation in precipitation wind speed, and temperature and it grows worse. Besides, ozone is a serious air pollutant in most of large cities. So worldwide, some of large cities are investing in forestry options to offset their climate problems, but lack of information has hindered comparisons of urban un cost effectiveness to other options. This research intends to study the economic benefits of tree shading of 19 parking lots in UCD campus. The economic benefits of tree shading are air conditioning savings, air quality, stormwater run-off, and other benefits. Especially, this study focuses how much the economic benefit of parking lot shading has been increased from 1995 to 2003 year by aerophoto. Some data on dimensions of parking lots and the number, size, tree species, and location of trees around each parking lot was inventoried. Two aerophotos(1995,2003) were used in order to analyze the increasement of tree canopy in 19 parking lots for 8 years. However, increasing coverage of trees and managing them for healthy growth would not be sufficient for avoiding adverse impacts by future climate change. Additional measures should be followed such as an increase of energy use efficiency and development of substitute energy. For example, coverage of trees help to save cooling energy by blocking solar radiation reaching parking cars and building structures through shading, and creating cool micro-climates through evapotranspiration. They also reduce heating demand by decreasing air infiltration and heat conduction out of the interior of buildings. Proper arrangement of vegetation over the parking lots can reduce cooling and heating costs. So proper planting design around hard space paving including species selection and location can significantly save cooling and heating energy. And a reduction in car and building's heating and cooling costs results in the reduction in energy demand which causes to emissions of air pollutants. Total increased tree canopy from 1995 to 2003 is $8,470.45m^2$ and the economic benefits is US$ 5,282.10. The economic benefit of one tree has been US$ 7.21 for 8 years. And an annually increased benefit is US$ 0.9 per a tree. If this kind of study is applied to studying the economic benefits of tree canopy in parking lots of Korea, it could result in guidelines of tree planting of parking lots. Because the trees selected for planting in parking lots were not suitable for an environment, the guidelines should contain a recommended list of trees. The guidelines should propose the shading percentage of parking lot when we plan a parking lot and contain the maintenance of trees in order to maximize the economic benefits of tree canopy.

• 생물환경조절학회지
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• 제29권2호
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• pp.130-140
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• 2020

본 연구는 대체에너지, 생태복원 및 밀원식물용 등으로 이용되어 묘목 수요가 증가되고 있는 쉬나무의 우량한 용기묘 생산을 위한 적정 차광수준을 구명하고자 실시하였다. 공시용기는 임업시설양묘용 플라스틱 용기(350ml/구)를 사용하였다. 차광수준은 전광과 전광의 35%, 55%, 75%로 처리하였다. 실험결과, 간장과 근원경 생장은 전광에서 현저히 높은 값을 보였으며, 차광수준이 강해질수록 낮은 생장값으로 조사되었다. 묘목의 뿌리형태특성을 측정한 결과 전광에서 뿌리발달이 가장 왕성하게 조사되었다. 건물생산량도 전광에서 가장 높았고 전체적으로 간장 및 근원경 생장 결과와 유사한 경향으로 나타났다. 묘목의 품질을 나타내는 지수인 QI(Quality Index)도 차광실험의 경우 전광에서 0.98로 가장 높게 조사되었다. 묘목의 엽록소 함량은 상대적으로 차광수준이 가장 높은 75% 차광처리에서 가장 높은 엽록소 함량을 보였으며, 광합성속도 및 수분이용효율은 전광에서 각각 8.48μmolCO₂·m^-2s^-1, 1.40μmolCO₂·mmolm^-1H₂O 가장 높은 것으로 조사되었다. 연구결과를 종합하면, 쉬나무 용기묘의 우량한 묘목생산을 위한 적정 차광수준은 전광(0%)으로 판단되며, 쉬나무 용기묘의 대량생산을 위한 기초자료로 활용될 것으로 기대된다.

• 반도체디스플레이기술학회지
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• 제17권1호
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• pp.40-44
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• 2018

In this paper, the efficiency of the solar system is lowered due to the partial shading such as the environmental factors of the solar panel. In order to solve this problem, a DC OPTIMIZER is proposed for a maximum power generation system of a photovoltaic panel. The proposed DC OPTIMIZER is composed of a buck structure that performs the maximum power point tracking (MPPT) control of each module of the solar panel, thus maximizing the efficiency. In order to verify the proposed DC Optimizer, the efficiency was measured by varying the irradiance using a solar simulator instead of the solar panel. As a result, it showed high efficiency characteristics as the maximum energy conversion efficiency was 99.3% at $800w/m^2$, $900w/m^2$, and the average efficiency was 99.06% excluding $100w/m^2$. The maximum efficiency of MPPT was 99.97% at $200w/m^2$, efficiency showed excellent performance.