• KIEAE Journal
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• v.16 no.6
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• pp.51-56
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• 2016

Purpose: As declines in the quality of residential environments occur, such as urban heat island effect, tropical night phenomenon, and violations of right to light and privacy due to urban densification and high rise building, these problems are emerging as social issues. In order to improve these issues, design factors which consider environmental aspects must be selected when planning apartment complexes, and ways to reflect them in the planning phase must be explored. Method: In this study, the analytical hierarchy process(AHP) was used to deduce design factors that considered environmental elements during the planning of apartment complexes. Furthermore, the priority and weight for each evaluation index were assessed. The objective was to propose a guideline for planning apartment complexes by finding the best solution for each evaluation index using complex weight values. Result: Floor area ratio was selected as the most important evaluation criterion in the environmentally conscious evaluation index for apartment complex planning. The shape and placement of skylights were selected as the most important evaluation criteria in the sunshine environment for a pleasant residential environment. Ground surface cover design was selected as the most important criterion in the outdoor thermal environment index for improving the microclimate within cities and apartment complexes. Thus, the results of this study can serve as an investigation guideline that concerns policy and regulations, and as reference data that can be used in planning apartment complexes.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.5
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• pp.65-73
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• 2015

The purpose of this study was to compare the Mean Radiant Temperature(MRT) under two landscaping shade membranes, white and black, with those of natural outdoor spaces at summer midday. An additional perforated black shading net was applied and compared for the consideration of the practical application. The average MRT at the height of 2.4m, 10cm below the membranes of black, white, and perforated black were $49.1^{\circ}C$, $41.6^{\circ}C$ and $36.8^{\circ}C$ respectively, while that of open sky was $41.8^{\circ}C$. This indicates that a closer position to the darker membrane caused a higher MRT. At the height of 1.1m and 1.7m, the difference of MRT between the black and the white membranes was slight, while the value of white was unexpectedly higher than the black. The MRT of black perforated net showed the lowest value at every height. The black membrane absorbed more solar radiation than the white, which caused the greater release of long wave radiation and higher temperature near the membrane itself. In spite of the higher albedo of the white membrane, the higher solar radiation transmittance rate of which seemed to cause the slightly higher MRT than the black at the hight of 1.1m and 1.7m. In summary, the performance of the black membrane was slightly better than the white in terms of the air conditioning of the human related space around the height of 1.1m and 1.7m, when the shading membranes were at 2.5m height.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.7
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• pp.799-804
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• 2014

To combine to the power transmission, photovoltaic inverter is demanded, because the photovoltaic system is generated direct current power. However, photovoltaic inverter is sensitive to high temperature. In the temperature rising such as at noon and on summer, efficiency of machine is decreased due to the loss increment. Because this problem causes national energy loss according to the expanding the photovoltaic industry, countermeasure is demanded. There, in this paper, we installed a cooling system using a thermoelement regardless of the temperature. Also, we analyze the cooling effect according to the position of two fans which improve the effect maximize.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.2
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• pp.60-67
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• 2017

The purpose of this study was to evaluate the influence of landscaping shade materials' porosity on the Mean Radiant Temperature (MRT) of summer outdoors. The MRTs were measured under seven different types of black membranes with holes of 8mm diameter at different intervals applied on the top of wooden boxes, and compared with those of four additional control plots with or without shade and lateral boxes. The applied porosities were 0.5, 1, 2, 4, 8, 16%, and 32%, and three groups of three shades were compared sequentially from August 13 to September 8, 2016. The MRTs under the shade without lateral block, no shade with lateral block, and shade with lateral block were $33.08^{\circ}C$, $45.80^{\circ}C$, and $42.3^{\circ}C$, respectively, while that of no-shaded no-lateral screen was $44.26^{\circ}C$, based on records from 11:00 AM to 3:00 PM on the days with a peak globe temperature higher than $30^{\circ}C$. An ANCOVA analysis showed that the MRTs under the shades with 0.5, 1, 2, 4, 8, 16%, and 32% porosities were calculated as 43.40, 43.10, 41.49, 40.43, 39.61, $37.91^{\circ}C$, and $38.12^{\circ}C$, respectively, while that in the no shaded control box was $45.8^{\circ}C$. The curve fitted between MRTs and the porosity showed a U-shaped quadratic function with the minimum MRT at 16% practically or 22.5% statistically.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.5
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• pp.617-624
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• 2014

Recently, photovoltaic inverter is received attention in photovoltaic with introduction of feed-in tariff. However, this inverter has problems such as inability to respond flexible at climate change due to its opening, and decrease of efficiency and lifetime due to its abnormal operation. To solve the problem, we desire to develop the eco-inverter which has a temperature control to respond easily on the change of temperature, and use the sealed structure not to affect the environment. In addition, we derive the optimal position of cooling system which is placed inside of inverter to minimize the power consumption, and proposed the effective measure to improve the efficient of inverter by deciding the number of cooling system.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.22-30
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• 2014

The purpose of this study was to compare the Solar Radiation(SR) and the Mean Radiant Temperature(MRT) under the shades of the three landscaping trees in clear summer daytimes. The trees were Lagerstroemia indica, Quercus palustris and Ulmus parvifolia. The solar radiation, the globe temperature and the air temperature were recorded every minute from the $1^{st}$ of April to the $30^{th}$ of September 2013 at a height of 1.1m above on the four monitoring stations, with four same measuring system consisting of a solar radiation sensor, two resistance temperature detectors(Pt-100), a black brass globe (${\phi}50mm$) and data acquisition systems. At the same time, the sky view photos were taken automatically hourly by three scouting cameras(lens angle: $60^{\circ}$) fixed at each monitoring station. Based on the 258 daily sky view photos and 6,640 records of middays(10 A.M.~2 P.M.) from the $1^{st}$ of June to the $30^{th}$ of August, the time serial differences of SR and MRT under the trees were analysed and compared with those of open sky, The major findings were as follows; 1. The average ratio of sky views screened by the canopies of Quercus palustris, Lagerstroemia indica and Ulmus parvifolia were 99%, 98% and 97%, and the SR were $106W/m^2$, $163W/m^2$ and $202W/m^2$ respectively, while the SR of open sky was $823W/m^2$. Which shows the canopies blocked at least 70% of natural SR. 2. The average MRT under the canopies of Quercus palustris, Lagerstroemia indica and Ulmus parvifolia were $30.34^{\circ}C$, $33.34^{\circ}C$ and $34.77^{\circ}C$ respectively, while that of open sky was $46.0^{\circ}C$. Therefore, it can be said that the tree canopies can reduce the MRT around $10{\sim}16^{\circ}C$. 3. The regression test showed significant linear relationship between the SR and MRT. In summary, the performances of the landscaping shade trees were very good at screening the SR and reducing the MRT at the outdoor of summer middays. Therefore, it can be apparently said that the more shade trees or forest at the outdoor, the more effective in conditioning the outdoor space reducing the MRT and the useless SR for human activities in summertime.

• Journal of the Korean Solar Energy Society
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• v.29 no.6
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• pp.81-87
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• 2009

The purpose of this study is to evaluate of the outdoor thermal environment by building scale and block type as variable factors. In this study, 18 cases of office in central business district that have different condition are compared about their surface temperature, HIP(Heat Island Potential), and MRT(Mean Radiant Temperature). They are simulated with 3-dimension numerical simulation software named Hoyano-model. The output results contain visualized distribution chart and numerical data. The results of evaluation are as follows. (1)The surface temperature of the building becomes higher as building coverage ratio is higher but floor area ratio is lower. In same conditions, unified block type is maximum $3.2^{\circ}C$ higher than divided block type. (2)HIP shows different daily pattern as block type. During daytime, divided block type is much higher than unified block type but after sunset, it is changed. (3)MRT shows different distribution pattern as sunlight moves expecially at noon. (4)As the results of this study, cases that have high floor area ratio condition show lower surface temperature by tendency to stay low indoor temperature in office building and big rate of windows on building surface.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.35-41
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• 2017

Materials exposed to outside will deteriorate due to various weathering factors such as sunlight, heat, temperature, humidity and so on. Therefore, predicting speed of degradation and life time is a very important issue. This research uses retro-reflective sheets with white and green which are most commonly used colors to conduct the outdoor exposure test and acceleration test of xenon arc in Arizona state in the United States, Chennai in India, Sanary in France and Seosan in Korea to measure the reflective performance of retro-reflection. The accelerated factor was obtained by using regression analysis through reflective values obtained from the acceleration test of xenon arc from Seosan area. Also, by using solar uv program, the accelerated factor of various climate regions were obtained and it was confirmed that the accelerated factor of Senary was 1.04, Arizona 1.82, Chennai 1.92 times higher than that of Seosan.

• Journal of the Korean Applied Science and Technology
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• v.39 no.2
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• pp.368-376
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• 2022

Spontaneous ignition occurs in industrial sites or anywhere in our lives, and is a phenomenon in which a substance ignites itself without an ignition source in the atmosphere. As the rate of chemical reaction increases, the heat generated increases, and the risk of spontaneous ignition increases. In this study, safe raw materials used for food and cosmetics were mixed to prepare coal spontaneous ignition prevention agents specifically among various spontaneous ignition phenomena. The effect of suppressing spontaneous combustion of coal was confirmed through lab and field tests with low-calorie, low-grade coal from Indonesia. As a result of the outdoor field test, the ignition prevention agent manufactured in this study compared with the control group(Fire after 90 days) showed excellent ignition inhibitors for more than 120 days. In addition, CO concentration control was confirmed by comparing the concentration of carbon monoxide for 50 days at the indoor coal yard. It was confirmed that the results were better than the comparative group coal and the existing anti-firing method. In addition, the possibility of coal fire prevention agents for indoor coal farms will be applied from 2024 was confirmed by studying the environment and safety of workers' working environments through official test such as soil and water quality test, MSDS of coal fire prevention agents in consideration of working workers, water quality, and eye irritation tests.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.6
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• pp.115-125
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• 2017

This study was to investigate the user's thermal environments under the pergola($L\;7,200{\times}W\;4,200{\times}H\;2,700mn$) covered with Wisteria floribunda(Willd.) DC. according to the variation of leaf area index(LAI). We carried out detailed measurements with two human-biometeorological stations on a popular square Jinju, Korea($N35^{\circ}10^{\prime}59.8^{{\prime}{\prime}}$, $E\;128^{\circ}05^{\prime}32.0^{{\prime}{\prime}}$, elevation: 38m). One of the stations stood under a pergola, while the other in the sun. The measurement spots were instrumented with microclimate monitoring stations to continuously measure air temperature and relative humidity, wind speed, shortwave and longwave radiation from the six cardinal directions at the height of 0.6m so as to calculate the Universal Thermal Climate Index(UTCI) from $9^{th}$ April to $27^{th}$ September 2017. The LAI was measured using the LAI-2200C Plant Canopy Analyzer. The analysis results of 18 day's 1 minute term human-biometeorological data absorbed by a man in sitting position from 10am to 4pm showed the following. During the whole observation period, daily average air temperatures under the pergola were respectively $0.7{\sim}2.3^{\circ}C$ lower compared with those in the sun, daily average wind speed and relative humidity under the pergola were respectively 0.17~0.38m/s and 0.4~3.1% higher compared with those in the sun. There was significant relationship in LAI, Julian day number and were expressed in the equation $y=-0.0004x^2+0.1719x-11.765(R^2=0.9897)$. The average $T_{mrt}$ under the pergola were $11.9{\sim}25.4^{\circ}C$ lower and maximum ${\Delta}T_{mrt}$ under the pergola were $24.1{\sim}30.2^{\circ}C$ when compared with those in the sun. There was significant relationship in LAI, reduction ratio(%) of daily average $T_{mrt}$ compared with those in the sun and was expressed in the equation $y=0.0678{\ln}(x)+0.3036(R^2=0.9454)$. The average UTCI under the pergola were $4.1{\sim}8.3^{\circ}C$ lower and maximum ${\Delta}UTCI$ under the pergola were $7.8{\sim}10.2^{\circ}C$ when compared with those in the sun. There was significant relationship in LAI, reduction ratio(%) of daily average UTCI compared with those in the sun and were expressed in the equation $y=0.0322{\ln}(x)+0.1538(R^2=0.8946)$. The shading by the pergola covered with vines was very effective for reducing daytime UTCI absorbed by a man in sitting position at summer largely through a reduction in mean radiant temperature from sun protection, lowering thermal stress from very strong(UTCI >$38^{\circ}C$) and strong(UTCI >$32^{\circ}C$) down to strong(UTCI >$32^{\circ}C$) and moderate(UTCI >$26^{\circ}C$). Therefore the pergola covered with vines used for shading outdoor spaces is essential to mitigate heat stress and can create better human thermal comfort especially in cities during summer. But the thermal environments under the pergola covered with vines during the heat wave supposed to user "very strong heat stress(UTCI>$38^{\circ}C$)". Therefore users must restrain themselves from outdoor activities during the heat waves.