전면적차광과 부분차광이 콩 엽록소 형광 반응에 미치는 영향

조유나 ( Yuna Cho ),조은이 ( Euni Jo ),정재혁 ( Jae-hyeok Jeong ),윤창용 ( Changyong Yoon ),안규남 ( Kyunam An ),조재일 ( Jaeil Cho ) 한국농림기상학회 2021 한국농림기상학회지 Vol.23 No.3

광은 식물 광합성에 반드시 요구되는 에너지이다. 차광의 종류를 전면차광과 부분차광으로 구분하고, 각각의 차광 조건에서 생육한 콩의 엽록소 형광을 관측하여 광합성능을 평가하였다. 전면차광에서는 SPAD값으로 대표되는 엽록소 농도와 광이용효율을 표현하는 ETR (Electron Transport Rate)이 크게 낮아졌다. 차광 박스 제거 후에 SPAD와 ETR 모두 대조구와 같은 정도가 되었으나, 열 소산 기작을 나타내는 NPQ (Non-Photochemical fluorescence Quenching)는 높아졌다. 이렇게 전면차광을 겪었던 콩의 광이용효율은 회복했지만, 높아진 NPQ가 광인산화 효율을 떨어뜨리므로 실제 노지 광합성량은 필연적으로 낮아질 것이다. 부분 차광에서도 SPAD와 ETR이 대조구와 큰 차이를 보이지 않았으나, NPQ는 높은 모습을 보였다. 따라서, 도시 농업 또는 영농형 태양광과 같은 부분차광 조건의 광합성량은 단순히 작물의 광이용효율과 누적 광 에너지량으로 계산한 추정값보다 작을 것으로 예상된다. The growth experiment under shading condition has been performed to understand the eco-physiological responses of crops to light in terms of photosynthesis. There are two types of shading: overall shading and partial shading. In this study, the chlorophyll fluorescence of soybean was observed under the overall shading of the box made by polyresin and the partial shading at agrivoltaic system. The overall shading condition during vegetative growth induced lower SPAD and Electron transport rate (ETR). These lower values recovered after removal of shading box. However, the Non-photochemical fluorescence quenching (NPQ) became lower under overall shading and higher under partial shading. Such increase in NPQ limited crop photosynthesis even though the ETR was almost same to the control without shading treatment. Under the condition of partial shading, the values of SPAD and ETR for soybean did not change. However, the NPQ was higher than control condition. This suggests that the crop photosynthesis under both types of shading would be decreased by different eco-physiological processes which are the lower ETR in overall shading and the higher NPQ in partial shading despite the reduced light under shading conditions.

Evaluation of a FPGA controlled distributed PV system under partial shading condition

Chao, Ru-Min,Ko, Shih-Hung,Chen, Po-Lung Techno-Press 2013 Advances in energy research Vol.1 No.2

This study designs and tests a photovoltaic system with distributed maximum power point tracking (DMPPT) methodology using a field programmable gate array (FPGA) controller. Each solar panel in the distributed PV system is equipped with a newly designed DC/DC converter and the panel's voltage output is regulated by a FPGA controller using PI control. Power from each solar panel on the system is optimized by another controller where the quadratic maximization MPPT algorithm is used to ensure the panel's output power is always maximized. Experiments are carried out at atmospheric insolation with partial shading conditions using 4 amorphous silicon thin film solar panels of 2 different grades fabricated by Chi-Mei Energy. It is found that distributed MPPT requires only 100ms to find the maximum power point of the system. Compared with the traditional centralized PV (CPV) system, the distributed PV (DPV) system harvests more than 4% of solar energy in atmospheric weather condition, and 22% in average under 19% partial shading of one solar panel in the system. Test results for a 1.84 kW rated system composed by 8 poly-Si PV panels using another DC/DC converter design also confirm that the proposed system can be easily implemented into a larger PV power system. Additionally, the use of NI sbRIO-9642 FPGA-based controller is capable of controlling over 16 sets of PV modules, and a number of controllers can cooperate via the network if needed.

컴퓨터 시뮬레이션을 통한 PV 적용 차양 시스템의 주광 특성 분석 및 경제성 평가

홍성관(Seong-Kwan Hong),최안섭(An-Seop Choi) 한국생활환경학회 2012 한국생활환경학회지 Vol.19 No.1

The shading system is a system that applies PV module to the shading device. Shading system can maximize benefits of daylight in the point of occupant comfort and energy savings. This study was to analyze characteristics of daylight distributions and evaluate the economic impact. In this study, shading system was simulated using Radiance of lighting simulation software for comparing daylight distributions. Economic evaluation using payback period was calculated by RETScreen of economic evaluation software. In calculating the payback period, the factors like initial cost, government support money, electricity charge rate, and others are included. The purpose of this study is to verify the applicability of shading system.

음영조건을 고려한 공동주택 옥상 태양광모듈의 배치계획 평가 연구

이겨레(Lee, Keo-Re),이윤선(Lee, Yoon-Sun),임재한(Lim, Jae-Han) 대한건축학회 2019 大韓建築學會論文集 : 構造系 Vol.35 No.5

During the initial design stage of apartment complex, the photovoltaic(PV) system has been considered as an alternative of renewable energy system and planned to install at the rooftop floor level in general. The electric power generation characteristics can be influenced by the block layout, building orientation and roof top structure because of azimuth angle, tilt angle, and partial shading. This study aims to investigate power generation characteristics of photovoltaic system in apartment buildings by considering the partial shading conditions due to the block layout, building orientation and roof-top structures. For the photovoltaic module arrangement planning in rooftop floor level, shading areas were firstly analyzed due to the adjacent building structure. And the annual and seasonal power generation of PV system were analyzed through the PVsyst simulation results. The results show that shading period at the roof top surface can be increased due to the parapet and water tank. Initial design power capacity can be decreased by considering the daily insolation period and distance between PV modules through the shading simulation. As the number of PV modules decreases, the annual power generation can be decreased. However annual power generation per unit area of PV modules can be increased and performance ratio can be increased above 80%. Also the power generation of PV system can be critically affected by building orientation and the performance ratio can be drastically decreased in east-oriented buildings due to the shading problems caused by adjacent structures at roof top level such as parapet and water tank.

Adaptive Partial Shading Determinant Algorithm for Solar Array Systems

Wellawatta, Thusitha Randima,Choi, Sung-Jin The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6

Maximum power point tracking (MPPT) under the partial shading condition is a challenging research topic for photovoltaic systems. Shaded photo-voltaic module result in complex peak patterns on the power versus voltage curve which can misguide classical MPPT algorithms. Thus, various kinds of global MPPT algorithms have been studied. These have typically consisted of partial shading detection, global peak search and MPPT. The conventional partial shading detection algorithm aims to detect all of the occurrences of partial shading. This results in excessive execution of global peak searches and discontinuous operation of the MPPT. This in turn, reduces the achievable power for the PV module. Based on a theoretical investigation of power verse voltage curve patterns under various partial shading conditions, it is realized that not all the occurrences of partial shadings require a global peak search. Thus, an intelligent partial shading detection algorithm that provides exact identification of global peak search necessity is essential for the efficient utilization of solar energy resources. This paper presents a new partial shading determinant algorithm utilizing adaptive threshold levels. Conventional methods tend to be too sensitive to sharp shading patterns but insensitive to smooth patterns. However, the proposed algorithm always shows superb performance, regardless of the partial shading patterns.

롤러 쉐이드와 베니션 블라인드의 높이에 따른 주광분포 비교

김유신(Kim Yu-Sin),박병철(Park Byoung-Chul),정근영(Jeong Keun-Young),최안섭(Choi An-Seop),이정호(Lee Jung-Ho) 대한건축학회 2007 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.27 No.1

The various shading systems were set up in office buildings, and the height of them can be controlled by user or timer. But generally users don't control the shading systems. It can't take an advantage of daylight such as improvement of work efficiency, reduction of energy, and so on. This study conducted experiments on daylight distribution for different height of the roller shade and the venetian blind at Lawrence Berkeley National Laboratory. The roller shading system was installed at one room, the venetian blind was installed at the other room, and another room had not any shading system. And conditions of experiment was 0%, 40%, 60%, and 80% of a height of the window for height of the shading system. This study investigated an analysis and comparison to illumination and distribution of illumination at the indoor. And this study can be used for development of shading systems that take advantage of available daylight in space.

Adaptive Partial Shading Determinant Algorithm for Solar Array Systems

Thusitha Randima Wellawatta,Sung-Jin Choi 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6

Maximum power point tracking (MPPT) under the partial shading condition is a challenging research topic for photovoltaic systems. Shaded photo-voltaic module result in complex peak patterns on the power versus voltage curve which can misguide classical MPPT algorithms. Thus, various kinds of global MPPT algorithms have been studied. These have typically consisted of partial shading detection, global peak search and MPPT. The conventional partial shading detection algorithm aims to detect all of the occurrences of partial shading. This results in excessive execution of global peak searches and discontinuous operation of the MPPT. This in turn, reduces the achievable power for the PV module. Based on a theoretical investigation of power verse voltage curve patterns under various partial shading conditions, it is realized that not all the occurrences of partial shadings require a global peak search. Thus, an intelligent partial shading detection algorithm that provides exact identification of global peak search necessity is essential for the efficient utilization of solar energy resources. This paper presents a new partial shading determinant algorithm utilizing adaptive threshold levels. Conventional methods tend to be too sensitive to sharp shading patterns but insensitive to smooth patterns. However, the proposed algorithm always shows superb performance, regardless of the partial shading patterns.

태양광 발전설비 안정성 향상을 위한 바이패스 다이오드 지능형 냉각 시스템

고재환(Jaehwan Ko),김충일(Chungil Kim),이충근(Chung-Geun Lee),이득광(Deukgwang Lee),고명근(Myeong-Geun Ko),고석환(Suk-Whan Ko),송형준(Hyung-Jun Song) 대한전기학회 2021 전기학회논문지 Vol.70 No.12

A Bypass diode maintains the efficiency and stability of photovoltaic systems (PV) under partial shading. However, the bypass diode failure may cause damage and fire in the PV system because the generated current continuously flows through it. Thus, we suggest an intelligent cooling fan system for the bypass diode to ensure the stability of PV. The cooling system consisted of a k-type temperature sensor, electrically controlled fan and auto-control system. If the temperature of bypass diode (Tdiode) exceeds specific points owing to partial shading and/or its failure, the cooling system will automatically turn on the fan to prevent bypass diode from abnormal heating. The analysis of Tdiode indicates that the system effectively decreases it below the melting point of the junction box (177 ℃). The cooling system is adequate for PV under partal shading or with a damaged diode. Consequently, our suggested intelligent cooling system can contribute to the safe operation of PV.

해상용 태양광 발전 시스템의 설치 각도에 관한 연구

오진석(Jin-Seok Oh),장재희(Jae-Hee Jang) 한국항해항만학회 2018 한국항해항만학회지 Vol.42 No.3

해상에서 운용되는 일점계류형 해양플랜트의 태양광 발전 시스템은 독립 전원 체계를 가지고 있으며, 해상 환경, 부조일수 등의 영향으로 안정적인 전력을 공급하는 것이 중요하다. 이러한 이유로 태양광 패널을 여러 방향으로 설치하게 되는데, 이 때 각 패널마다 입사되는 광량이 달라지므로 부분음영현상이 발생하게 된다. 육상용 태양광 발전시스템의 발전량은 위도의 영향을 받으므로 우리나라의 경우 30~36° 사이의 각도로 설치하는 것이 일반적이나, 일점계류형 해양플랜트에 설치되는 태양광 발전 시스템의 경우 부분 음영 현상에 의해 최대전력점이 제어 가능 범위 밖에 존재하는 경우가 발생하게 되고 이는 전력 발전 손실이 된다. 이 때 두 패널의 광량차이를 줄임으로써, 최대 전력점을 MPPT 알고리즘이 추종 가능한 범위에 존재하게 하여 발전 효율을 더 높일 수 있으며, 시뮬레이션 결과 설치각도 20°에서 가장 높은 발전 효율 가짐을 확인하였다. A solar power generation system on single point moored offshore plant has independent power system In order to satisfy the maritime environment and account for the number of sunless days, it is important to supply stable electric power to the systems. For these reasons, solar panels are installed in multiple directions. However, a partial shading effect occurs because the amount of light incident on each panel is different. The generated power by the solar generation system installed on land is affected by the latitude, then it is installed at an angle of 30 to 45°. in the case of Korea. In the case of a solar power generation system installed in a mooring type of marine plant, there is a possibility that the maximum power point is outside of the controllable range due to the partial shading effect. Therefore, a power generation loss occurs. By reducing the light amount difference between both panels, the maximum power point can exist in a range where the MPPT algorithm can track the power. The purpose is so the power generation efficiency can be further increased. In this paper, simulation results show that the highest power generation efficiency is obtained at an installation angle of 20°.

Digital Shade Analysis System을 이용한 전치부의 색조 특성에 관한 연구

김희은,조인호,임주환,임헌송,Kim Hee-Eun,Cho In-Ho,Lim Ju-Hwan,Lim Hun-Song 대한치과보철학회 2003 대한치과보철학회지 Vol.41 No.5

Statement of problem : A scientific examination and understanding of overall aspects of the natural dentition is the first step involved in making a satisfactory selection in the shade of an aesthetic prosthesis. Proper natural shade selection of the prosthetic restoration that is in harmony with the remaining dentition is as important aesthetically, as harmony of form and function in the anterior dentition. Clinically, the most commonly applied method of shade selection has been visual, but because of the subjective nature inherent to this method, shade selection results are variable and can be influenced by such factors as the technician, the type of shade guide used, and the type and intensity of the lighting. Purpose : The purpose of this study was to develop a more objective and scientific approach to examining and understanding the shade of teeth, which has in turn lead to the development of a number of shade analysis devices that present a more objective method of shade analysis. Material and Method : In this study, the shades of healthy anterior teeth were examined and analyzed using the recently developed digital shade analysis of the $ShadeScan^{TM}$ System. The study examined 80 individuals in their twenties, 40 males and 40 females, presenting 6 healthy, unrestored maxillary anterior teeth. Tooth brushing and oral prophylaxis were performed prior to evaluation. The ShadeScan handpiece was used to acquire images of the 6 maxillary anterior teeth. These images were analyzed using the Vita/Classical mode of the $ShadeScan^{TM}$ Software, and shade maps of each tooth were acquired and divided into cervical, middle, and incisal thirds. The shade distribution of each third, left and right symmetry, and gender differences were investigated and analyzed. Results : The results of the study are as follows : 1. An overwhelming majority of the examined teeth were found to possess shades belong to Group A, with the greatest variations occurring at the middle and cervical thirds of the maxillary central and lateral incisors, in both male and female subjects. 2. Canines of both male and female subjects showed left and right symmetry with uniform shade distribution of A4 and C4, while the lateral and central incisors showed left-right symmetry of the incisal 1/3 with a uniform shade distribution of A2 and A3 shades 3. No significant differences in shade distribution were seen between genders in maxillary canines, whereas maxillary central and lateral incisors showed differences at the middle and cervical thirds between male and female subjects The results of this study show that with the exception of maxillary canines, maxillary anterior teeth display a diverse shade distribution as well as gender differences. Conclusion : Clinically, when making a shade selection using the existing shade guide, one must consider the fact that even a single tooth consists of a variety of shades. The results of this study show that when selecting a shade from a number of groups is difficult, shades from A group are the most consistent with the natural shade or maxillary anterior teeth.