• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.120-120
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• 2022

Agrivoltaic System (AVS) was introduced with the concept that it could generate electricity by using the extra light remain after crops use for photosynthesis in farm, which can earn additional income. However, crop yield was declined under the AVS condition due to the decrease in light energy. In the past, many researchers have been studied about crop states under shading conditions. However, the phenomenon of partial shading such as under the AVS is not well studied. In this study, to figure out the response of crop under the different light conditions, the electron transport rate (ETR) and non-photochemical quenching (NPQ) of rice was investigated using the chlorophyll fluorescence measurement. Also, physiological changes of crops under the shading conditions were investigated. The growth experiment under partial shading under AVS and overall shading which made of 35% shade cloth was conducted to understand the eco-physiological responses of rice to light in terms of the photosynthesis. Under the shading conditions, SPAD value and chlorophyll contents were higher, but the leaf thickness was lower than control. The overall shading condition show lower ETR than others during the growing season. In contrast, NPQ was higher than other treatments. This means the available light energy cannot contribute to photosynthesis under the shading condition.

• 한국자원식물학회지
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• 제11권1호
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• pp.86-92
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• 1998

The photosynthetic rate (LPS)in the field was higher in the non-shading condition than in the shading. The fertilizer application was somewhat higher than non-fertilizer application. After humus application at 50% sading condition the growth and LPS increased with Ligularia fischeri. The maximum LPS at 80% shading was 22.3${\mu}{\textrm}{m}$mol/m/s with N-fertilizer application . Except Aster tataricus and Solidago virge-aurea. var. asiatic where the maximum LPS at non-shading and N-fertilizer application were 38.68 and 35.28${\mu}{\textrm}{m}$mol/m2/s. While the maximum LPS of Aster scaber was 30.01${\mu}{\textrm}{m}$mol/$m^2$/s at non-shading and non-fertilizer application. the growth rate was higher shading and fertilized conditions than non-shading and non-fertilized . The most effective shading condition was 50% , but leaf ration was highest in the 80% . But a. tataricus was favorable at non-shading and N-feritlized conditions.

• 토지주택연구
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• 제10권3호
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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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• 제15권1호
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• pp.83-88
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• 2015

This study aims to develope the light-weight PV blinds with windows and to investigate the shading analysis by the control conditions. For the study, the polycarbonate characteristics and coating methods are analyzed and the PV blind design for a small office is suggested. Also, the mock-up model of a suggesting system was made. The field tests were controled based on a solar altitude under clear sky conditions. As results, it is necessary to use a polycarbonate instead of a tempered glass for a light-weight PV. The shading effects of blind systems are high in slat angle $30^{\circ}$ and low in $0^{\circ}$. Also, the shading ratio is more affected by solar latitude than solar altitude. The shading change rate is relevantly constant on the solar altitude.

• 한국환경과학회지
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• 제29권2호
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• pp.167-175
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• 2020

The purpose of this study was to investigate the effect of shading on the growth and productivity of strawberries. Photosynthesis was normally achieved under natural light without shading treatment, and vegetative growth of under- and aboveground part of strawberry plants were excellent. Strawberry fruit productivity and quality were different depending on shading conditions. In natural light, they were improved possibly by balanced vegetative and reproductive growth. However, under light-shading conditions with insufficient sunshine, photosynthetic activity deteriorated and carbohydrate production was therfore inadequate; this adversely affected plant height and quality. The negative effects were more pronounced at 50% shading condition. Shading treatments resulting in insufficient sunshine had a detrimental impact on plant productivity and growth; this implies that proper shading conditions could heip improve yield and fruit quality.

• 한국환경복원기술학회지
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• 제11권6호
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• pp.104-111
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• 2008

Plant growth and variegated leaf color changes of three leaf variegated Sedum spectabile varieties 'Variegatum', 'Frosty Morn', red colored 'Washfield Ruby', and one Sedum lineare variety 'Variegatum' and Sedum sarmentosum under three levels of shading conditions were examined for leaf ornamental value improvement. Shading levels were 40%($1,500{\mu}mol{\cdot}m-^2{\cdot}s-^1$), 70%($750{\mu}mol{\cdot}m-^2{\cdot}s-^1$) and 85%($375{\mu}mol{\cdot}m-^2{\cdot}s-^1$). Improvements of leaf ornamental value of 'Variegatum' 'Frosty Morn' and 'Washfield Ruby' were observed at 40% shading level and plant heights and leaf sizes were also increased. Plant height of S.sarmentosum were shorten under direct sun light condition and leaf color changed to greenish yellow(RHS143B) but deep green color(RHS144A) was observed under shading conditions. Endurance of S.sarmentosum was stronger than other species and leaf ornamental values remained well at 70% shading level. Leaf width of S.lineare 'Variegatum' were not changed under shading conditions but leaf length was increased. Leaf color was Deep green color was greenish yellow under direct sun light but deepest green color was observed at 85% shading level. Consider all ornamental value criteria, best shading conditions for S.lineare 'Variegatum' were ranged 40% to 70%.

• Advances in Energy Research
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• 제5권4호
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• pp.289-304
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• 2017

Large glazed surfaces and windows become common features in modern buildings. The spread of these features was influenced by the dependence of designers on mechanical and artificial systems to provide occupants with thermal and visual comfort. Countries with hot summer and cold winter conditions, like Jordan, require maximum shading from solar radiation in summer, and maximum exposure in winter to reduce cooling and heating loads respectively. The current research aims at designing optimized double-positioned external shading device systems that help to reduce energy consumption in buildings and provide thermal and visual comfort during both hot and cold seasons. Using energy plus, a whole building energy simulation program, and radiance, Lighting Simulation Tool, with DesignBuilder interface, a series of computer simulations for energy consumption and daylighting performance were conducted for offices with south, east, or west windows. The research was based on comparison to determine the best fit characteristics for two positions of adjustable horizontal louvers on south facade or vertical fins on east and west facades for summer and winter conditions. The adjustable shading systems can be applied for new or retrofitted office or housing buildings. The optimized shading devices for summer and winter positions helped to reduce the net annual energy consumption compared to a base case space with no shading device or with curtains and compared to fix shading devices.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권1호
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• pp.65-68
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• 2013

A photovoltaic array exhibits several local and single global maximum power points under partial shading conditions. To track the global maximum power point precisely, a novel global maximum power point tracking scheme is proposed in this paper. In the proposed scheme, robustness of the tracking performance has been improved by enhancing searching profile. In addition, the paper addresses the tracking failure condition, and provides the experimental verification with several simulation and experimental results.

• 새물리
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• 제68권11호
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• pp.1215-1224
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• 2018

Most solar photovoltaic (PV) modules frequently get shadowed, completely or partially, resulting in a reduction of PV generation. This paper presents and compares the results from simulations and experimental measurements of the power output from a single PV module under various shading conditions. The study was carried out with a 90 W PV module and a 250 W PV module. The shaded area was increased from 0 to 100% for both variable and constant irradiances to analyze the effect of fluctuations in the solar irradiance certain shading conditions. The effect of shading for irradiance levels from 100 to $900W/m^2$ was investigated. Results showed that for every $100W/m^2$ decrease in the solar irradiance level, the power output decreased by 9, 0.7 and 1.5 W at 0, 25 and 50% shading, respectively. For solar irradiance levels higher than $500W/m^2$, the temperature increased by 1.6, 2.7 and $1.1^{\circ}C$ at 0, 25 and 50% shading, respectively, for every $100W/m^2$ increase in the irradiance.

• Journal of Power Electronics
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• 제17권6호
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• pp.1600-1610
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• 2017

We propose maximum power extraction from a rooftop solar photovoltaic (PV) array during partial shading conditions. Partial shading is unavoidable during power extraction from rooftop PV systems due to nearby tall buildings (construction of additional floors) and trees (growth of trees). Many reconfiguration techniques can be used to extract maximum power in partial shading conditions, but in several cases, the real maximum power output is not achieved. In this study, a new switched PV technique is proposed to enhance the power output. The proposed technique is simple to use and more cost effective than other reconfiguration techniques. Therefore, it is suitable for rooftop applications. The power output of the proposed technique is compared with that of existing techniques with similar shading patterns. Eight panels with ratings of 250 watts (2 kW) each are used for testing. MATLAB simulation and hardware verification are done for the proposed and existing techniques. The proposed technique is implemented on a $4{\times}2$ PV array, although it can be extended to a number of arrays.