• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.157.1-157.1
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• 2016

In this work, we experimentally investigated the solar absorption performance of Cu-based scalable nanostructured surfaces and compared their performance with the conventional TiNOX. We fabricated Cu-based nanostructured surfaces with a controlled chemical oxidation process applicable to a large area or complex geometry. We optimized the process parameters including the chemical compounds, dipping time and process temperature. We conducted both lab-scale and outdoor experiments to characterize the conversion efficiency of each absorber surfaces with single and double glazing setup. Lab-scale experiment was conducted with $50mm{\times}50mm$ absorber sample with 1-sun condition (1kW/m2) using a solar simulator (PEC-L01) with measuring the temperature at the absorber plate, cover glass, air gap and ambient. From the lab-scale experiment, we obtained ${\sim}91^{\circ}C$ and $94^{\circ}C$ for CuO and TiNOX surfaces after 1 hr of solar illumination at single glazing, respectively. To measure the absorber performance at actual operating condition, outdoor experiment was also conducted using $110mm{\times}110mm$ absorber sample. We measured the solar flux with thermopile detector (919P-040-50). From outdoor experiment, we observed ${\sim}123^{\circ}C$ and $131^{\circ}C$ for CuO and TiNOX with 0.6 kW/m2 insolation at double glazing, respectively. We showed that the suggested nanostructured CuO solar absorber has near-equivalent collection efficiency compared with the state-of-the-art TiNOX surfaces even with much simpler manufacturing process that does not require an expensive equipment.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.341-344
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• 2003

There are many problems in management of high-rise building construction performed in downtown area due to limited spaces and equipments for increasing kinds and quantities of material. By these restrictions, problems such as increase of construction cost. delay of construction period, decrease of productivity, occurrence of accident are caused. Recently, studies on JIT concept have focused on construction materials as a solution for the problems. But, studies about finishing material are insufficient yet. Accordingly, this study suggests flowing of current material management, JIT management effect, and development direction of lifting-up and procurement system with Low-emissivity double Glazing, among of main finishing materials.

• KIEAE Journal
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• v.15 no.6
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• pp.101-109
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• 2015

Purpose: Glazing and shading devices influence a lot on the thermal and visual environment in office buildings. Solar heat and daylight are contrary concept, therefore proper arrangement of thermal and optical performance is needed when designing a glazing and shading devices. The purpose of this study is to examine the conditions of the glazing and shading devices available for promoting the reduction of cooling loads + lighting loads and the improvement in thermal comfort and visual comfort for the summer season in an office building installed with venetian blind. Method: This study established 12 simulation cases which have different glazings and the positions of venetian blind for evaluating different thermal and optical performance. And by using EnergyPlus v8.1 and Window v7.2 program, we quantitatively analyzed cooling loads + lighting loads, thermal comfort and visual comfort in an office building installed with the glazing and shading devices. Result: Consequently, Case 9(Double Low-E+Exterior Blind) is the best arrangement of solar heat gain and daylight influx, thereby becomes the most excellent case of reducing cooling+lighting loads(46.8%) and simultaneously becomes the enhancement case in thermal comfort. Also, DGI(Daylight glare index) under clear sky conditions in summer was evaluated to be 19.6, and thereby satisfied the recommendation level of allowing visual comfort.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.567-572
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• 2013

In houses that use heating and cooling system, most of heat loss occurs through the windows, so that low-E glass, double-layered glass, and vacuum glazing are used to minimize the heat loss. In this paper, an encapsulating process that is a final process in manufacturing the vacuum glazing has been studied, and bonding in a vacuum chamber rather than atmospheric bonding was considered. For the efficiency of the encapsulating process, frit-melting temperature and bonding time were optimized with heater temperature, and the glass preheating temperature was optimized to prevent glass breakage due to thermal stress. Thus the vacuum glass was successfully manufactured based on these results and heat transmission coefficient measured was about $5.7W/m^2K$ which indicates that the internal pressure of the vacuum glazing is $10^{-2}$ torr.

• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.11
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• pp.458-465
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• 2016

The purpose of this research is to improve the thermal effiency of solar collector and to quantitatively analyze its performance. Solar thermal systems have been limited to water heating systems mainly using low-temperature range. However, through diverse developments, the application has been extended to medium- and high-temperature fields such as solar heating, solar air conditioning, and solar thermal industrial process. Among the diverse research, this research is specially focusing on enhancement of the thermal performance by minimizing the heat loss coefficient of flat plate solar collectors. In order to do it, a front-side glazing material and a back-side insulation material with high insulated structure is proposed and based on computational analysis, the performance of energy collecting volume of the proposed solar collector is analyzed. The research shows that the proposed structure has the excellent performance at medium- and high-temperature range. therefore, it is expected that the proposed structure can easily replace existing technologies.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.11
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• pp.972-980
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• 2002

This work is aimed at estimating the effects of various factors on the energy consumption of Korean-style apartment houses using TRNSYS. The factors considered here include the nominal size of floor area, type of remodeling, azimuth, sidewall insulation, and window type. Based on some assumptions, an actual apartment house is simplified into a model that is used for thermal load calculations. The simplified model is validated by showing a good agreement with the actual one in the predicted result. Remodeling balconies into unconditioned buffer spaces yields a favorable thermal performance in comparison with the original type regardless of the nominal size. Incorporating balconies into a conditioned indoor space leads to sharp increases in thermal loads, which must be avoided in view of energy conservation as well as structural problem. A quantitative assessment on the azimuthal effect indicates that the heating energy can be saved up to 16％ by taking the south or southeast direction. Reduction in the heating load with enhancing the sidewall insulation is gradual, so that a cost-effectiveness analysis may be needed when amending the regulations concerned. Glazing appears to significantly affect the heat transfer through window. A typical case illustrates that the heating load is decreased about 25％ by simply adopting triple glazing instead of double glazing.

• Korean Institute of Interior Design Journal
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• v.24 no.4
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• pp.91-98
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• 2015

Double skin façade is known that several features affected the building energy and daylighting performance. That is why the envelope is able to consist of all architectural materials such as glass, aluminum, wood and insulation for vision of residents and workers in buildings. Its specifications is very diverse according to the building designers and building owners. In recent times, visual environment became a major focus and resulted in the development of cutting edge engineering of diverse glazing systems and shading devices by growing interests of friendly environment. Thus this research has evaluated the fluctuations of interior lighting and atmospheric conditions based on double skin facade systems. Especially in terms of daylighting environment as dependent on solar variations, this research provides quantitative analysis of interior lighting conditions and how it affects the living conditions as well as improve the design of interior spaces.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.2
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• pp.191-199
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• 2005

Double pane window system, in which an air layer with a finite width is filled between glasses, is used in order to increase the insulation efficiency. In the present study, a conjugate heat transfer problem of a double pane window system has been studied numerically in order to investigate the effect of an air layer on the heat transmittance of the double pane window system using a finite element method based on P2P1 basis function. In this study on the conjugate heat transfer of a double pane window system, numerically predicted Nusselt numbers with or without conjugate heat transfer effect have been compared with an available existing empirical formula. It has been found that a Nusselt number from an existing formula for an enclosed space is different from that obtained from the present conjugate heat transfer analysis mainly due to the effects of a very high aspect ratio and conjugate heat transfer mechanism. Furthermore, it has been shown that the numerically estimated optimal air thickness of the double pane window system with conjugate heat transfer effect is a little bit longer than that obtained without considering conjugate heat transfer effect.

• Journal of the Korean Solar Energy Society
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• v.34 no.5
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• pp.89-99
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• 2014

The determination of the solar and thermal performance of fenestration is required for the evaluation of fenestration energy performance, estimating building load. Presently, there exist several methods for determining the thermal transmission(U-value) and solar heat gain coefficient (SHGC) of fenestration system. These method are commonly grouped under calculation or experimental methods. While U-value testing and calculation methods have been long established, SHGC has been evaluated only by the method of calculation under the lack of any established testing method. However, it is difficult to assess the exact SHGC for various types of fenestration with sun-shading or other solar control systems. The purpose of this study was to evaluate the effect of interior venetian blind and roll screen on the SHGC of glazing system. SHGC has been evaluated by the KS L 9107 test method and exiting calculation method for precise comparison of the energy performances of various shading devices. In this research, the test sample consists of three different types of double glazing unit with venetian blind and roll screen. Slat angles of venetian blind were changed to $-45^{\circ}$, $0^{\circ}$, and$-45^{\circ}$. For the roll screen, measurements were taken with the roll screen in the closed position. In result, the venetian blind reduced SHGC by 21.2~28.4% at $45^{\circ}$, when compared to the double glazing unit. The roll screen reduced SHGC by 34.4~41.7% at closed. The differences between the measured and calculated SHGC were found to range between 0.001(0.2%) and 0.047(11.1%) for all test cases. For the cases of venetian blind $-45^{\circ}$, $0^{\circ}$ and $45^{\circ}$, the deviation ratio were 3.6~9.8%, 1.1~2.6%, 4.2~11.1%, respectively. For the case of roll screen, the deviation ratio were 4.1~5.7%.