• Journal of Conservation Science
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• v.37 no.2
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• pp.90-100
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• 2021

Outdoor cultural buildings and their accessories receive different amounts of solar radiation depending on their location's latitude, azimuth, and tilt. Shading is also affected by the surrounding terrain and objects, necessitating individual and quantitative shading analysis. In July 2019, this study conducted a shading analysis on the tops, midpoints, and bottoms of wooden pillars in the azimuth of Cheongpunggak, a traditional building in South Korea's National Research Institute of Cultural Heritage. The shading analysis found that the solar access/shade predicted by the solar trajectory meter was 30 minutes slower than measured in the field. The highest solar access and solar radiation levels came from the south, followed by the west, east, and north. The pillars' bases received the highest solar access and solar radiation, followed by their midpoints and tops. Solar access was high at tilt 90°, but solar radiation was high at tilt 0°, due to the light-collection efficiency and the irradiance. Shading on the pillars' tops was caused by the roof eaves, while shading on the midpoints and bases were affected by the surrounding pillars, topography, and other objects. Simultaneous solar access at the tops, midpoints, and bottoms was possible for 365 days for the northwest, west, and southwest pillars but only from October to March for the south and southeast pillars.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.274-277
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• 2011

We measured a solar irradiation of vertical and horizontal surface per azimuth in southern area of Korea using pyrheliometer. In comparison with the provided data from ASHRAE and CIBSE, the average amount of solar irradiation has much variation of 10 to 150% in reference with north direction. In the clear day, the measured value has much difference with the value of ASHRAE and there is similar trend in case of CIBSE. The reason why amount of irradiation of clear day is differ from the average value, is able to be assumed that the value of ASHRAE and CIRSE is made of assumption based on clear days. The result of analysis of ASHRAE and CIBSE values according to the amount irradiation value for vertical and horizontal surface per azimuth using the MBE, RSME, and t-Statistic show that the CIBSE value has more reliability for the MBE, RMSE, and t-Statistic values than ASHRAE value.

• Solar Energy
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• v.18 no.2
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• pp.69-89
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• 1998

The measured solar radiation incident on tilted surfaces by all directions has been widely used as important solar radiation data in installing solar collectors, hot water systems, and photovoltaic modules, and in designing solar buildings and houses. To maximize the incident beam radiation, the slope, which is the angle between the plane of the surface in question and the horizontal, and the solar azimuth angles are needed for these solar applied systems. To respond to above needs, a theoretical study with actual measurements on moving route of the sun is carried out. This study focuses on the development of an solar expert system and on the selection of slopes for solar absorber plates in Korea.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.7
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• pp.492-497
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• 2011

The objective of this research is to study the variation of optimum slope angles of collectors for seven regions in Korea, which are Seoul, Gangneung, Daejeon, Daegu, Gwangju, Busan and Jeju. The results for 2000~2007 are analyzed to sec if adjustment of slope angles is necessary each year to receive maximum solar radiation. For an azimuth fixed solar collector, solar radiation of yearly optimized slope angle during May~Sept.(summer), Nov.~Mar.(winter) and the whole year are greater than the fixed slope angle by 0.03%, 0.02%, and 0.04%, respectively. For an azimuth tracking solar collector, solar radiation of yearly optimized slope angle during May~Sept.(slimmer), Nov.-Mar.(winter) and the whole year are greater than the fixed slope angle by 0.03%, 0.07%, and 0.04% respectively. It is unnecessary to adjust slope angles each year for both azimuth fixed and tracking collectors, since the gains are insignificant. Solar radiation of the azimuth tracking solar collector during May~Sept., Nov.~Mar. and the whole year are greater by 14.7%, 16.0%, and 19.2% than the azimuth fixed solar collector.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.85-85
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• 2022

영농형 태양광발전은 태양의 일사량을 전기발전과 영농에 공유하는(solar-sharing) 방식이다. 본 연구는 신재생에너지의 활용의 극대화를 위하여 추적식 영농형 태양광발전시스템을 구축하고 시설하부에서 일정 기간 재배중인 작물의 하부 환경과 생육을 조사하여 영농형태양광 하부작물개발을 위한 기초자료를 확보하고자 하였다. 구축한 추적식 영농형 태양광발전시스템은 4열 6단의 24장 모듈(8m × 6m)을 가지며, 발전시설 중심축 기둥 간 중심간격 14m로 단일지주식 스크루 공법으로 순천대학교 부속농장 답작포(순천시 죽평리)에 설치하여 하부 환경과 하부작물의 생육을 조사하였다. 태양광발전시설 하부작물의 생육을 조사하기 위하여 순천 농협육묘장에서 벼(신동진)를 육묘하여 2022년 6월 16일 이앙하였다. 태양광발전시스템 하부 지역을 4방위 방향에 따라 강음영(중심축으로부터 1~3m), 중음영(5m), 약음영(7~9m) 구역으로 설정하여 생육을 조사한 결과, 방위에 따른 초장은 남쪽에서 음영간 차이가 상대적으로 낮게 나타났으며, 1번기 태양광 발전시설에 의하여 음영이 중첩된 2번기 시설의 동쪽에서 대조구 대비 초장이 상대적으로 낮은 경향을 나타내었다. 음영강도에 따른 초장은 대체로 강음영구에서 낮게 나타났으며, 약음영구로 갈수록 높게 나타났다. 엽수는 방위에 따라서, 그리고 음영의 강도에 따른 차이가 초장에 비하여 작게 나타났다. 출수기의 경우 방위별로는 남쪽에서 음영별 차이가 작게 나타났으며, 음영강도에 따라서 차이를 보였다. 또한 태양광시설 하부에 데이터수집장치(Model 1650, Spctrum Technonogies, USA)를 설치하여 음영에 따른 토양전도도, 토양함수량, 토양온도, par light 등 생육환경을 조사, 비교하였다.

• Journal of Korean Society of Forest Science
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• v.82 no.2
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• pp.152-165
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• 1993

This is the basic study in order to know the amount of transpirational water loss in a Larix leptorepis stand by a heat pulse method. Especially this study has been measured and discussed the diurnal and seasonal trends of heat pulse velocity by changes of radiation, temperature and humidity, differences of heat pulse velocity by direction and depth in stem, differences of heat pulse velocity by dominant, codominant and suppressed trees, diurnal change of heat pulse velocity by change of leaf water potential, sap flow path way in sapwood by dye penetration and amount of daily and annual transpiration in a tree and stand. The results obtained as follows : 1. Relation between heat pulse velocity(V) and sap flow rate(SFR) was established as a equation of SFR=1.37V($r=0.96^{**}$). 2. The sap flow rate presented in the order of dominant, codominant and suppressed tree, respectively. The daily heat pulse velocity was changed by radiation, temperature and vapor pressure deficit. 3. The heat pulse velocity in individual trees did not differ in early morning and in late night, but had some differed from 12 to 16 hours when radiation was relatively high. 4. The heat pulse velocity and leaf water potential showed similar diurnal variation. 5. The seasonal variation of heat pulse velocity was highest in August, but lowest in October and similar value of heat pulse velocity in the other months. 6. The heat pulse velocity in stem by direction was highest in eastern, but lowest in southern and similar velocity in western and northern. 7. The difference of heat pulse velocity in according to depths was highest in 2.0cm depth, medium in 1.0cm depth, and lowest in 3.0cm depth from surface of stem. 8. The sap flow path way in stem showed spiral ascent turning right pattern in five sample trees, especially showed little spiral ascent turning right in lower part than 3m hight above ground, but very speedy in higher than 3m hight. 9. The amount of sap flow(SF) was presented as a equation of SF=1.37AV and especially SF in dominant tree was larger than in codominant or suppressed tree. 10. The amount of daily transpiration was 30.8ton/ha/day and its composition ratio was 83% at day and 17% at night. 11. The amount of stand transpiration per month was largest in August(1,194ton/ha/month), lowest in May (386ton/ha/month). The amount of stand transpiration per year was 3,983ton/ha/year.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.171-173
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• 2008

The amount of incident solar rays on inclined surfaces with various directions has been widely utilized as important data in installing solar collector, hot water system, and designing solar buildings and house. This is because the performance of the solar energy applied systems is much affected by angle and direction of incident rays. Recognizing those factors mentioned above are of importance, actual experiment has been performed in this research to obtain the angle of inclination with which the maximum incident rays can be absorbed. The results obtained in this research could be used in designing optimal solar thermal systems.

• Journal of the Korean Solar Energy Society
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• v.21 no.3
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• pp.19-24
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• 2001

The amount of incident solar rays on inclined surfaces with various directions has been widely utilized as important data in installing solar collector, hot water system, and photovoltaic module, and designing solar buildings and house. This is because the performance of the solar energy applied systems is much affected by angle and direction of incident rays. Recognizing those factors mentioned above are of importance, actual experiment has been peformed in this research to obtain the angle of inclination with which the maximum incident rays can be absorbed. The results obtained in this research could be used in designing optimal solar systems.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.288-299
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• 1996

This is the basic study to investigate the amount of transpirational water loss in thrifty mature Quercus mongolica stand by the heat pulse method. The differences of heat pulse velocity by direction and depth, differences of heat pulse velocity by dominant, codominant and suppressed trees, diurnal changes of heat pulse velocity due to the change of leaf water potential, vapor pressure deficit and radiation, and sap flow path way in sapwood by dye penetration were measured in stems. Finally the amounts of daily and annual transpiration in stand were calculated by the heat pulse velocity. The results obtained were summarized as follows : 1. Relationship between heat pulse velocity(V) and sap flow rate(SFR) was obtained as a equation of SFR=1.37V. 2. The sap flow rate was high in the order of dominant, codominant, and suppressed trees. The daily heat pulse velocity changed with radiation, temperature and vapor pressure deficit. 3. The heat pulse velocity showed the similar diurnal variation as the leaf water potential change. 4. The heat pulse velocity showed the highest value in May(4.0cm/hr in average), the lowest one in July(2.9cm/hr in average). 5. The heat pulse velocity in the same stem presented the highest value in the northern direction, medium in western, and the lowest in southern and eastern. 6. The heat pulse velocity in stem was highest in 0.5cm, medium in 1.0cm, and lowest in 1.5cm depth from the surface of stem. 7. The sap flow path way in stem showed sectorial straight ascent pattern in four sample trees. 8. The amount of sap flow(SF) was presented as a equation of $SF=1.37A{\cdot}V$(A: the cross-sectional area of sapwood, V: heat pulse velocity), and especially SF was larger in dominant tree than codominant and suppressed trees. 9. The amount of daily transpiration was 5.6ton/ha/day, and its composition ratio was 72% at day and 28% at night. 10. The amount of stand transpiration per month was largest in May(168ton/ha/month), lowest in July(125ton/ha/month). The amount of stand transpiration per year was 839ton/ha/year.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.6
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• pp.461-466
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• 2012

Recently, building energy systems with solar collector and solar module have increased to improve energy problem, a heat island, a global warming and carbon dioxide emissions. In this study, value of solar radiation in areas was analyzed using TRNSYS simulation, and the optimum tilt and orientation angle for installing a photovoltaic module was examined. Average values of the weather data in the past twenty years in areas were used as input data. The results show that the tilt angle of a photovoltaic module for gaining the annual maximum solar radiation varies in different localities, and values of the annual solar radiation gained by using the variable photovoltaic module increased by 2.5 percent as compared with that gained by using the fixed photovoltaic module. When fixed photovoltaic module is installed, it should be examined the tilt and orientation angle for installing a photovoltaic module was examined.