• Land and Housing Review
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• v.5 no.4
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• pp.315-323
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• 2014

In this study, thermal transmittance which is a parameter to measure the thermal performance was evaluated for an internal insulation versus an external insulation. Then the ISO regulation was applied to evaluate it, and the superiority of an external insulation was verified by the thermal transmittance values. The three zones of apartment housing were selected to evaluate the performance. (1) The junction of an outer wall and a protruded slab : If there is no a thermal bridge protection system, then the values are about same in the two insulation systems, so the protection system should certainly be installed. If it is installed, then the value for the external insulation is 2 times lower than internal system. (2) The junction of a side wall and a flat slab: The value is 0.509W/mK for the internal insulation and about zero for the external insulation. (3) The junction of an outer wall and a division wall: The value is 0.451W/mK for the internal insulation and also about zero for the external insulation. A domestic regulation that could evaluate a thermal transmittance has to be established by applying the ISO regulation for the evaluation of external insulation systems in apartment housing in the future. Additionally, the government must decide which length should be used for the national standard.

• 월간 기계설비
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• s.7
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• pp.95-95
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• 1990

• Journal of the Korea Institute of Building Construction
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• v.21 no.3
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• pp.203-211
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• 2021

Recently, the insulaton design standards for reducing the energy use of buildings have been strengthened. Althoug insulation work is the most cost-effective method for reducing the primary energy consumption per unit area of a building, there are no evaluation criteria for insulation performance at the time of construction and completion inspection. The purpose of this study is to provide objective data by establishing a standard for an analysis method and a method for easily experimenting with the exterior wall thermal transmittance of an apartment house using a thermal transmittance measuring device(TESTO 435). For the exterior wall of the test subject, the specific heat per unit area exceeded 20kJ/(m²·K), and the data at the end point suitable for ISO 9869-1 were analyzed by the average method. The measured values of the thermal transmittance for 3 consecutive days converged within +5% of the desing value, and the standard deviation of the thermal transmittance by day decreased in the order of 1-Day > 3-Day > 2-Day. The standard deviation of the thermal transmittance by time period decreased in the order of 00:00~24:00 < 19:00~07:00 < 00:00~07:00. The measured value of the thermal transmittance for the time perion of 00:00 to 07:00 per day almost coincided with an error of -3% to + 2% compare to the desing value.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.419-428
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• 2021

In order to develope a mobile-based greenhouse energy calculation program, firstly, the overall thermal transmittance of 10 types of major covers and 16 types of insulation materials were measured. In addition, to estimate the overall thermal transmittance when the cover and insulation materials were installed in double or triple layers, 24 combinations of double installations and 59 combinations of triple installations were measured using the hotbox. Also, the overall thermal transmittance value for a single material and the thermal resistance value were used to calculate the overall thermal transmittance value at the time of multi-layer installation of covering and insulating materials, and the linear regression equation was derived to correct the error with the measured values. As a result of developing the model for estimating thermal transmittance when installing multiple layers of coverings and insulating materials based on the value of overall thermal transmittance of a single-material, the model evaluation index was 0.90 (good when it is 0.5 or more), indicating that the estimated value was very close to the actual value. In addition, as a result of the on-site test, it was evaluated that the estimated heat saving rate was smaller than the actual value with a relative error of 2%. Based on these results, a mobile-based greenhouse energy calculation program was developed that was implemented as an HTML5 standard web-based mobile web application and was designed to work with various mobile device and PC browsers with N-Screen support. It had functions to provides the overall thermal transmittance(heating load coefficient) for each combination of greenhouse coverings and thermal insulation materials and to evaluate the energy consumption during a specific period of the target greenhouse. It was estimated that an energy-saving greenhouse design would be possible with the optimal selection of coverings and insulation materials according to the region and shape of the greenhouse.

• Journal of Korea Foresty Energy
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• v.21 no.2
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• pp.62-68
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• 2002

Adiabatic property of plywood wall panel was examined to evaluate their thermal conductivities. The amount of heat loss was investigated through overall heat transmission experiment. Styroform and grass wool showed less heat loss. However, yellowsoil board and laminated lumber showed high volume specific heat capacity. When the changes of indoor and outdoor temperature were checked in model house, wall manufactured with styroform and grass wool was affected easily by the changes of outdoor temperature. Yellowsoil, the mixed board of yellowsoil and sawdust, and laminated lumber, which have high volume specific heat capacity, were not affected much. The rates of overall heat transmission were much better in styroform and grasswool, but the adiabatic properties were much higher in yellowsoil board and the mixed board of yellowsoil and sawdust. The results showed that the insulating material can be developed using yellowsoil and wood, which are nature friendly materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5284-5289
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• 2011

This study focused to evaluate thermal transmittance(U-value) performance of sliding type of aluminum alloy window frame(AAWF) with double glazing(DG) and glazing spacer and that without thermal breaker in winter and summer season by two dimensional steady state heat transfer analysis. The AAWE was installed to an existing educational facilities in Seosan area which is the southern region of the Korean Peninsula. Analysis of 2D steady-state heat transfer was performed through the use of BISCO as calculation and simulation program. U-value and temperature factors were calculated. The results are as followed. First, the isotherm simulation shows that AAWF with double glazing have serious differences from recently proposed window thermal performance standards such as Insulation Performance of Windows and Doors of Building Energy Saving Design Standards and the results of calculation of thermal transmittance performance of AAWF and DG are U=9.631 W/$m^2K$, U=2.382 W/$m^2K$ respectively during winter and summer season. Second, the results of analysis of heat transfer analysis, calculated by simulation, shows that 225% of heat is lost comparing with thermal performance standards U=4.0 W/$m^2K$ of general double glazing among those standards on AAWF without thermal breaker.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.103-103
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• 2002

목적：자화율 대조법을 사용한 관류 영상에서 동시획득 $T_{1}T_{2}^{*}$ 강조 경사 자장 펄스열을 사용하여 Gd-DTPA에 의한 $T_{1}T_{2}^{*}$ 감소 효과를 동시에 획득하여 종양의 치료 효과, 판정에 중요한 기준을 제시할 수 있는 정확한 관류 정보를 얻고자 한다. 대상 및 방법： Gd-DTPA에 의한 $T_{1}T_{2}^{*}$ 감소 효과를 동시에 획득하기 위하여 기존의 이중 경사자장 펄스열을 수정, 동시획득 $T_{1}T_{2}^{*}$ 강조 경사자장 펄스열을 개발하였고, 시간 해상도를 높이기 위하여 key-hole 방법을 사용하였다. 고정 phantom으로 Sephadex를 다양한 농도의 Gd-DTPA 용액에 swelling하여 사용하였고, 관류 phantom으로는 Sephadex와 Dialyzer를 사용하였다. Sephadex는 swelling 하였을 때 $T_1$, $T_2$값이 생체 조직의 값과 비슷하고, 물을 관류시킬 수 있어 생체 모형에 적합한 phantom이다 .관류 phantom은 정량 펌프에 연결하여 사용하였다. Sephadex 관류 phantom에서는 분당 약 4$m\ell$ 속도로 관류시키면서 25 mM Gd-DTPA을 0.1$m\ell$ 일시 주입하여 관류 방향에 수직인 coronal 영상을 약 15분 동안 얻었다. 투과도를 구하기 위한 phantom으로는 hollow fiber type Dialyzer를 사용하였고, in vivo에서 1차 관류 이후에 현관 밖에서의 Gd농도가 높고 혈관 내부의 농도가 낮은 상태를 만들기 위하여 fiber 바깥쪽으로 500 mM Gd-DTPA 2 ml를 미리 넣어두고 fiber 내부로 이보다 낮은 농도의 Gd 용액을 관류시키면서 약 1시간동안 영상을 얻었다. 관류 영상에서 $T_1$/$T_{2}^{*}$ 감소 효과를 구분하여 구한 $\DeltaR_1$, $\DeltaR_2$ 곡선의 적분값으로부터 관류량을 구하고, 2 구획 모델을 적용하여 투과도를 구했다.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.127-127
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• 2002

목적： 자화율 대조법을 사용한 관류 영상에서 동시획득 $T_{1}{/}T_{2}^{*}$ 강조 경사 자장 펄스열을 사용하여 Gd-DTPA에 의한 $T_{1}{/}T_{2}^{*}$ 감소 효과를 동시에 획득하여 종양의 치료 효과, 판정에 중요한 기준을 제시할 수 있는 정확한 관류 정보를 얻고자 한다. 대상 및 방법： Gd-DTPA에 의한 $T_{1}{/}T_{2}^{*}$ 감소 효과를 동시에 획득하기 위하여 기존의 이중 경사자장 펄스열을 수정, 동시획득 $T_{1}{/}T_{2}^{*}$ 강조 경사자장 펄스열을 개발하였고, 시간 해상도를 높이기 위하여 key-hole 방법을 사용하였다. 고정 phantom으로 Sephadex를 다양한 농도의 Gd-DTPA 용액에 swelling하여 사용하였고, 관류 phantom으로는 Sephadex와 Dialyzer를 사용하였다. Sephadex는 swelling 하였을 때 $T_1$, $T_2$값이 생체 조직의 값과 비슷하고, 물을 관류시킬 수 있어 생체 모형에 적합한 phantom이다. 관류 phantom은 정량 펌프에 연결하여 사용하였다. Sephadex 관류 phantom에서는 분당 약 4$m\ell$ 속도로 관류시키면서 25 mM Gd-DTPA을 0.1$m\ell$ 일시 주입하여 관류 방향에 수직인 coronal 영상을 약 15분 동안 얻었다. 투과도를 구하기 위한 phantom으로는 hollow fiber type Dialyzer를 사용하였고, in vivo에서 1차 관류 이후에 혈관 밖에서의 Gd 농도가 높고 혈관 내부의 농도가 낮은 상태를 만들기 위하여 fiber 바깥쪽으로 500mM Gd-DTPA 2$m\ell$를 미리 넣어두고 fiber 내부로 이보다 낮은 농도의 Gd 용액을 관류시키면서 약 1시간동안 영상을 얻었다. 관류 영상에서 $T_{1}{/}T_{2}^{*}$ 감소 효과를 구분하여 구한 $\Delta{R}_{1}$, $\Delta{R}_{2}^{*}$ 곡선의 적분값으로부터 관류량을 구하고, 2 구획 모델을 적용하여 투과도를 구했다.

• Proceedings of the KAIS Fall Conference
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• 2012.05b
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• pp.756-758
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• 2012

인구증가와 지속적인 산업발전으로 인하여 건축이 매우 활발해지고 냉난방으로 인한 에너지 소비가 급증하게 되면서 효율적인 에너지 사용의 필요성이 크게 대두되었다. 건물에서 손실되는 에너지의 약 20~40%가 창문을 통해 손실이 일어나며 이를 해결하고자 현재 Low-E 유리, 복층유리등 다양한 방법들이 개발되어 사용하고 있으며 에너지 손실을 더욱 낮추기 위하여 진공유리가 개발 중이나 아직 보급은 이루어지지 않고 있다. 본 논문에서는 진공유리의 열관류율 측정 장치와 진공에서의 중요한 열전달 요인인 복사열전달이 진공유리 성능에 미치는 영향을 3차원 수치해석을 통하여 알아보았다.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.647-657
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• 2015

To investigate a method for calculation of the heating load for environmental designs of horticultural facilities, measurements of total heating load, infiltration rate, and floor heat flux in a large-scale plastic greenhouse were analyzed comparatively with the calculation results. Effects of ground heat exchange and infiltration loss on the greenhouse heating load were examined. The ranges of the indoor and outdoor temperatures were $13.3{\pm}1.2^{\circ}C$ and $-9.4{\sim}+7.2^{\circ}C$ respectively during the experimental period. It was confirmed that the outdoor temperatures were valid in the range of the design temperatures for the greenhouse heating design in Korea. Average infiltration rate of the experimental greenhouse measured by a gas tracer method was $0.245h^{-1}$. Applying a constant ventilation heat transfer coefficient to the covering area of the greenhouse was found to have a methodological problem in the case of various sizes of greenhouses. Thus, it was considered that the method of using the volume and the infiltration rate of greenhouses was reasonable for the infiltration loss. Floor heat flux measured in the center of the greenhouse tended to increase toward negative slightly according to the differences between indoor and outdoor temperature. By contrast, floor heat flux measured at the side of the greenhouse tended to increase greatly into plus according to the temperature differences. Based on the measured results, a new calculation method for ground heat exchange was developed by adopting the concept of heat loss through the perimeter of greenhouses. The developed method coincided closely with the experimental result. Average transmission heat loss was shown to be directly proportional to the differences between indoor and outdoor temperature, but the average overall heat transfer coefficient tended to decrease. Thus, in calculating the transmission heat loss, the overall heat transfer coefficient must be selected based on design conditions. The overall heat transfer coefficient of the experimental greenhouse averaged $2.73W{\cdot}m^{-2}{\cdot}C^{-1}$, which represents a 60% heat savings rate compared with plastic greenhouses with a single covering. The total heating load included, transmission heat loss of 84.7~95.4%, infiltration loss of 4.4~9.5%, and ground heat exchange of -0.2~+6.3%. The transmission heat loss accounted for larger proportions in groups with low differences between indoor and outdoor temperature, whereas infiltration heat loss played the larger role in groups with high temperature differences. Ground heat exchange could either heighten or lessen the heating load, depending on the difference between indoor and outdoor temperature. Therefore, the selection of a reference temperature difference is important. Since infiltration loss takes on greater importance than ground heat exchange, measures for lessening the infiltration loss are required to conserve energy.