• KIEAE Journal
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• v.17 no.2
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• pp.29-34
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• 2017

Purpose: Recently, significant heat loss through the window takes place in buildings. Nevertheless, there exists little literature concerning the exterior horizontal shading devices and the design criteria are not clearly settled yet. Applying the exterior horizontal shading devices is more efficient as compared to the interior shading devices in that solar radiation can be directly blocked before passing through the window or the envelope. The purpose of this study is to reduce the internal load by designing the exterior horizontal shading devices and verify the degree of reduction in energy consumption. Method: This study aims to reduce energy consumption in cooling and heating through proposing proper length and shape of the exterior horizontal shading devices in public buildings. In the process, actual energy data and the Design Builder simulation program are utilized. In addition, economic aspect is considered to figure out the optimal length of the exterior horizontal shading devices that maximizes efficiency. Result: As a result, the proper length and shape of the exterior horizontal shading devices are provided as follows: 1) Energy consumption in cooling and heating is minimized when the exterior horizontal shading devices are designed as 0.5m*2. 2) Electricity bill is the lowest when the exterior horizontal shading devices are designed as 3.3m*2. The gap between maximum and minimum electricity bill is about 7.8~14%.

• Horticultural Science & Technology
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• v.17 no.1
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• pp.29-32
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• 1999

This experiment was conducted to investigate the effect of different levels of shading (0, 35, 55, 75, 95% to incident sunlight) on the growth of Hedera rhombea Bean and Pachysandra terminalis Sieb. et Zucc. in order to determine optimum light intensity for ground cover plants. H. rhombea showed a upright growth type under 95% shading and P. terminalis was highest under 35% shading. Number of branches was not significantly affected by shading levels. Stem diameter and length were reduced under shading from 35% to 95%. Leaf growth was vigorous under 35% and 55% shade condition. Leaves became longer with decreasing light intensity, but shorter in 95% shading than control. There was a slight trend that total chlorophyll and chlorophyll a, b contents increased with decreasing light intensity, and so did chlorophyll a/b ratio. Fresh and dry weight of both plants were higher under 35, 55, and 75% shading than control and 95% shading. Specific leaf weight tended to decrease with reduction of light intensity. Thus, optimum light intensity for growth of them may be 35 and 55% shading of incident sunlight. In addition, it is possible to grow them under even 75% shading of incident sunlight.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.584-589
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• 2014

Jeffersonia dubia is a spring-flowering perennial found in rich forests in Korea and Northern China and has potential as an ornamental or medicinal plant. However, illegal picking and land use change have decreased the number of populations and overall population size of this plant in its natural habitat. Although J. dubia has been reported to be a shade-preferring plant, no study has determined the optimum light intensity for its growth. The objectives of this work were to observe the effects of various shading levels on the physiological responses of J. dubia and to determine the proper shading level for cultivation. Treatments consisted of four shading levels (0%, 50%, 75%, and 95% shade) imposed using black mesh cloth. The number of leaves and dry weight increased with decreased shading. The shoot-to-root ratio increased with increased shading, mainly due to decreased root dry weight under shading. Plants showed low net $CO_2$ assimilation rates and $F_v/F_m$ values combined with low dry matter levels when grown under 0% shade (full sunlight). These results indicate that J. dubia plants experience excessive irradiance without shading, resulting in damage to the photosynthetic apparatus. By contrast, the net photosynthesis rate increased as the shading level increased. $F_v/F_m$, the potential efficiency of PSII, was 0.8 under 95% shade, indicating that J. dubia is well-adapted under heavy shading. However, the low dry matter of plants in the 95% shade treatment indicated that the low light intensity under 95% shade led to a decline in plant growth. Thus, moderate light (50% shading) is recommended for cultivating J. dubia without physiological defects.

• 한국약용작물학회:학술대회논문집
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• 2008.11a
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• pp.169-170
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• 2008

• Journal of Korean Society of Forest Science
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• v.95 no.5
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• pp.614-620
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• 2006

To study the chlorophyll contents and photosynthetic characteristics of 4 tree species of deciduous hardwoods; Betula platyphylla var. japonica, Zelkova serrata, Acer mono and Prunus sargentii were treated in 3 stages of shading; the full sun treatment, the medium shade treatment with 30% of transmittance comparing to full sun, the intense shade treatment with 8% of transmittance and their changes in chlorophyll contents and photosynthetic characteristics were examined and analyzed. Most hardwoods showed differences in the total chlorophyll contents in the order of May < September < July, however, that in Prunus sargentii increased progressively along with the lapse of time. Concerning the degree of shading, total chlorophyll contents increased in proportion to the level of shading. Betula platyphylla var. japonica and Prunus sargentii showed more than 2-3 times difference between the full sun treatment and the intense shade treatment. The changes in photosynthetic characteristics, the range of the light saturation point of the trees was $1,000{\sim}1,100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in May, before the shading was applied, and the intensity was shown in the order of Betula platyphylla var. japonica > Zelkova serrata > Acer mono > Prunus sargentii. The photosynthetic rate was $6.4{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}{\sim}27.1{\mu}mol{\cdot}CO_2{\cdot}m^{-2}{\cdot}s^{-1}$ in the order of Betula platyphylla var. japonica > Prunus sargentii > Acer mono > Zelkova serrata that there were differences between species. Concerning the changes in light saturation point in each growth period after shading treatment, the light saturation point in the full sun treatment was found in the range of $560{\sim}1,100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and the level of intensity was shown in the order of May > July > September. The light saturation point decreased as the level of shading intensified and the level of changes in light compensation point in the full sun treatment for Betula platyphylla var. japonica and Prunus sargentii was shown in the range of $2.9{\sim}27.1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in the order of May > July > September, however, for Zelkova serrata and Acer mono was shown in the range of $3.9{\sim}11.7{\mu}mol{\cdot}CO_2{\cdot}m^{-2}{\cdot}s^{-1}$ in the order of July > May > September that there were differences between species.

• Korean Journal of Medicinal Crop Science
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• v.27 no.4
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• pp.278-283
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• 2019

Background: High temperature damage in ginseng is influenced by shading materials related not only to temperature, but also to light intensity and light quality. To address, this green-colored khaki shading sheet is widely used. As they are recently, developed, there is limited research information about their attributes and use. Methods and Results: The four-layered shading net (FLSN), blue-colored shading sheet (BCSS), aluminum-coated shading board (ACSB), and green-colored shading sheet (GCSS) were installed in the wooden A type of sun-block facilities. Two layered black, shading net was additionally used to cover the facilities since the beginning of June. The average temperature at the facility where different shades were tested was in the order of BCSS ($28.9^{\circ}C$) > FLSN ($27.7^{\circ}C$) > GCSS ($27.6^{\circ}C$) > ACSB ($27.1^{\circ}C$). However, high temperature injury rates were in order: FLSN > ACSB > GCSS > BCSS. Root weight vaired and was in the order: ACSB > GCSS > BCSS > FLSN. Conclusions: High temperature damage is possible not only because of temperature increase, but also due to various environmental light factors. Ginseng high temperature injury was minimal when BCSS or GCSS were used by difference of light quality. Although the root weight was higher in ACSB, it could be vulnerable to high temperature damage. Therefore, we propose using GCSS for ginseng shading.

• Journal of Korean Living Environment System
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• v.24 no.6
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• pp.810-823
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• 2017

The envelope is important for sustainable building. Recent commercial buildings are causing thermal degradation and cooling load due to the increase of the area of the windows. Therefore, this research studied kinetic shading system which can improve energy saving and visual environment in summer. For that, this study proposed new shading system and shape considering the orientation of the building and the location of the sun. Based on this, this study analyzed the effectiveness on energy reduction and improvement of visual environment by applying the kinetic shading system proposed in this study. As the results of this study, energy reduction rate was 35% in the east, 22.9% in the south, and 30.7% in the west depending on the application location. Also, as the result of the illuminance analysis, it was found that the effect of achieving uniformity ratio of illumination was considerable.

• Plant Resources
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• v.4 no.1
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• pp.13-25
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• 2001

Growth and yield of licorice were investigated under the different conditions of photoperiod and shading in order to establish its cultural practice for the domestic production with the aim to substitute the import. The photoperiod was adjusted to 8,10, and 12 h by shielding plants from the light with blackout curtain. Large seedlings(11-20g) appeared to be affected by photoperiod since around 65 days. Most of growth parameters, including plant height, number of leaf, fresh and dry weight of plant and root, were the highest in 12 h photoperiod among all the photoperiod levels, excepting stem diameter which was the highest in 10 h photoperiod(4.5mm). Each photoperiod was similar to each other in root length and diameter. Small seedlings(4-l0g) showed a similar trend to large seedlings. The results from field photoperiod experiment demonstrated that 12 h photoperiod was also the best among three photoperiod treatments in plant height, stem diameter, number of leaf, root length, fresh and dry weight of plant and root. The effect of shading was tested under the three levels of control (0%), half-shading (55%), and full shading (90%). Shading remarkably suppressed the growth and yield, compared to no-shading. Although plant height and root length were little affected by the shading, stem and root diameters were heavily reduced.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.96-103
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• 2012

Annual energy consumption in detached houses are affected mainly by thermal performance of envelope. In particular the performance of glasses are critical due to global wanning and climatic change. Therefore, this research analyzes annual consumption of cooling and heating energy with various combination of U-value, shading coefficient and building orientation. The simulation results shows that shading coefficient of glazing contributes to the changes of proportion of heating and cooling energy demand and the optimized shading coefficient for minimizing energy consumption varies with buildings orientation.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.5
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• pp.169-179
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• 2019

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.