• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.2
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• pp.111-120
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• 2004

The optimal design method of indoor thermal environment using CFD coupled simulation and genetic algorithms (GA) is developed in this study. CFD could analyze the thermal environment considering the distribution of temperature, velocity, etc. in a room. Therefore, It would be appropriate to use CFD for the optimal design method considering their distribution. In this paper, the optimal design means the most appropriate boundary conditions of the room among the conditions where the design target of indoor therm environment is achieved. Two step optimal indoor thermal environment design method is proposed. It includes the GA for searching the optimal indoor thermal environment design. To examine the performance of this method, the optimal design of hybrid ventilation system, which uses the natural cross ventilation and the radiation-cooling panel is conducted. The optimal design which satisfies the design target (thermal comfort, minimum cooling load, minimum vertical temperature difference) is found using two step optimal design method.

• Journal of the Korean institute of surface engineering
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• v.25 no.2
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• pp.90-96
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• 1992

Thed effects of sputter gas pressure and substrate surface micro-roughness on the microstructure and surface topography have been investigated in the Cu thin films sputter deposited onto polyimide substrates. The surface roughness of polyimide was controlled by oxygen rf plasma treatment. In the Cu film deposited at the pressure of 5 mtorr, the surface is smooth and the columnar structure is not visible regardless of polyimide surface more open boundaries. The polyimide surface roughness enhances these effects, These phenomena can be explained in therm of atomic shadowing effect.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.10-18
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• 2007

The purpose of this study is to develop an user-friendly computer program which can analyze the thermal performance of high-rise curtain wall. In this study, the sub-routines for FVM SOLVER, HIGH-RISE CONDITION CALCULATION, AUTOMATIC SPECIFICATION BOUNDARY/MESH, MATERIAL DATABASE, and GRAPHICAL CONDENSATION/U-FACTOR OUTPUT were developed by using Visual Basic. The curtain wall heat conduction simulation results of program showed good agreement with those of FLUENT and THERM. The minimum and maximum relative error rates were 3.17 and 9.68% compared to other software.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.222-226
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• 2009

The parts of building which has the most influence on thermal load are skins, outer walls and windows. Among them, window is the worst weak point of building even if it has many advantage of solar radiation gain than other parts. The present time, many researches on various performance of window and many types of system-window are being made. This study evaluates thermal performance of tilt & sliding system window by simulation program Therm 5.2 and Window 5.2. After making a sample model improving it's thermal weak point, this study evaluates real thermal performance of system window. As a result, this study understands manufacture ability condition of domestic company and proposes a research plan of system window.

• Land and Housing Review
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• v.11 no.3
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• pp.61-68
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• 2020

Advanced glazing systems with excellent heat transmission values (Ug-Value) have been developed to reduce the energy consumption and the greenhouse gas emission. This study proposes a triple glazing system consisting of gaps with a vacuum and a carbon dioxide gas layer which is one of greenhouse gases. As a fundamental stage, this study is focused on calculating the optimal glazing thickness and the Ug-Value via a computer simulation, Therm & Window package. As the results, it was presented that the optimal thickness of the proposed triple glazing system is 22.2 mm, and the Ug-Value is 0.273 W/㎡·K. If this glazing system is to be applied to buildings, it could not only reduce building energy consumption but could also contribute to the treatment of carbon dioxide gas which is one of greenhouse gases.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.75-80
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• 2012

Gasification is a therm-chemical conversion process to convert various solid fuels into gaseous fuels under limited supply of oxygen in high temperature environment. Considering current availability of biomass resources in this country, the gasification is more attractive than any other technologies in that the process can accept various combustible solid fuels including plastic wastes. Mixed fuels of biomass and polyethylene pellets were used in gasification experiments in this study in order to assess their potential for synthesis gas production. The results showed that higher reaction temperatures were observed in mixed fuel compared to woodchip experiments. In addition, carbon monoxide, hydrogen, and methane concentrations were increased in the synthesis gas. Heating values of the synthesis gas were also higher than those from woodchip gasification. There are hundred thousand tons of agricultural plastic wastes generated in Korea every year. Co-gasification of biomass and agricultural plastic waste would provide affordable gaseous fuels in rural society.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.437-441
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• 1991

During the evaporation of garlic juice by centrifugal thin film evaporator (Centri-Therm, CT-1B), the effect of feeding rate was investigated for its operation properties. On the process condition of feeding rate of 25 to 125 kg/h, theoretical average thickness of the garlic juice film on the rotating cone and residence time of the juice in the evaporator varied in the range of 0.52 to 0.89 mm and 1.77 to 6.75 second, respectively. And the flow of garlic juice was considered as a streamline flow by Reynolds number. At constant temperatures of steam and juice evaporation, concentration ratio decreased with the increase of the feeding rate. But the evapoartion rate and overall heat transfer coefficient increased with the increase of the feeding rate until the feeding rate reached a certain value and then decreased. On the conditions of $25{\leq}$feeding rate ${\leq}125\;kg/h$, evaporation temperature of $40^{\circ}C$, $95{\leq}steam$ $temperature≤120^{\circ}C$ and initial feed concentration of $32^{\circ}Brix$, concentration ratio and overall heat transfer coefficient were $1.04{\sim}2.04\;and\;3,074.33{\sim}17,614.70kJ/m^{2}{\cdot}h{\cdot}^{\circ}C$.

• Journal of the Korean earth science society
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• v.30 no.3
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• pp.294-304
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• 2009

A statistical prediction model for the typhoon intensity and track in the Northwestern Pacific area was developed based on the artificial neural network scheme. Specifically, this model is focused on the 5-day prediction after tropical cyclone genesis, and used the CLIPPER parameters (genesis location, intensity, and date), dynamic parameters (vertical wind shear between 200 and 850hPa, upper-level divergence, and lower-level relative vorticity), and thermal parameters (upper-level equivalent potential temperature, ENSO, 200-hPa air temperature, mid-level relative humidity). Based on the characteristics of predictors, a total of seven artificial neural network models were developed. The best one was the case that combined the CLIPPER parameters and thermal parameters. This case showed higher predictability during the summer season than the winter season, and the forecast error also depended on the location: The intensity error rate increases when the genesis location moves to Southeastern area and the track error increases when it moves to Northwestern area. Comparing the predictability with the multiple linear regression model, the artificial neural network model showed better performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.310-316
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• 2019

In automotive application, customers are demanding high efficiency and various functions for convenience. The demand for these automotive applications is steadily increasing. In this study, it has been studied the analysis of heat flow to improve the PCB(printed circuit board) heating performance of WPC (wireless power charger) recently developed for convenience. The charging performance of the wireless charger has been reduced due to power dissipation and thermal resistance of PCB. Therefore, it has been proposed optimal PCB design, layout and position of electronic parts through the simulation of heat flow analysis and PCB design was analyzed and decided at each design stage. Then, the experimental test is performed to verify the consistency of the analysis results under actual environmental conditions. In this paper, The PCB modeling and heat flow simulation in transient response were performed using HyperLynx Thermal and FloTHERM. In addition, the measurement was performed using infrared thermal imaging camera and used to verify the analysis results. In the final comparison, the error between analysis and experiment was found to be less than 10 % and the heating performance of PCB was also improved.

• Journal of the Korean Solar Energy Society
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• v.30 no.3
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• pp.10-15
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• 2010

The aim of this study was to analysis the Heating/cooling performance of Solar Window System built in apartments. The solar window is the idea to integrate daylight as a third form of solar energy into a PV/Solar Collector system and allows more control due to the possibility to close the reflectors. However, there can be a conflict between the desire for on one hand daylight and view and on the other hand optimal energy conversion for the PV/Solar Collector system. The process of this study is as follows: 1) The Solar Window system is designed through the investigation of previous paper and work. 2)The simulation program(ESP-r, Therm5.0, Window6.0) was used in energy performance analysis. The reference model of simulation was made up to analysis energy performance on Solar Window system. 3)Selected reference model(Floors:15, Area of Unit:$148.5m^2$) for heating/cooling energy analysis, Energy performance simulation with various variants, such as U-value of Solar Window system according to its position and angle. Consequently, When Solar Window system is equipped with balcony window of Apartment, Annual heating and cooling energy of reference model was cut down about 5%~11%.