• Journal of Welding and Joining
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• v.28 no.1
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• pp.92-99
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• 2010

For the last couple of decades many studies have been carried out to find out solutions to improve the effectiveness and productivity of the plate forming process. The practical way for the automation of the plate forming process has not been, however, developed yet. Since the characteristics of heating machines may be different form each other, it is necessary to investigate the thermal deformation characteristics of the heating machine to be used in the automation system. And their characteristics may be updated as new information about thermal deformation by heating is accumulated. In this paper, data base system has been constructed based on the results of experiments and numerical analyses, which will be used in deriving the deformation estimation formula. The computer code which can automatically derive the deformation estimation formula has been also developed. This paper also illustrates how the formula is updated as experimental data are added. From the present findings, it can be said that the automatic deriving procedure may be important in the automated plate forming system since the heating line information to be generated must be directly influenced by the deformation estimation formula.

• Journal of Institute of Convergence Technology
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• v.6 no.1
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• pp.7-11
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• 2016

An experiment was performed to show the bio-signal characteristics of the Stuckyi when was heated. To measure the bio-signal of the plant, this study used the electrode with copper(+) and constantan(-). The electrode was directly inserted into the Stuckyi stems. And used T-type thermocouple to measure the inside temperature of the Stuckyi. During the experiments, room temperature also measured with T-type thermocouple. Heating was made with hair dryer periodically that 3 times turned on for heating 5 min and off for non-heating 25 min. Under the situation, the responses of the Stuckyi including voltage potential and inside temperature were measured using data logger(HP-34970A) according to the distances(15cm, 30cm, 45cm) between hair dryer and the plant. Through the experiments, We knew that the inside temperature has similar level and behavior with the room temperature at normal state. And during heating period, the inside temperature and the potential were also simultaneously increased sharply. From the experiments, we revealed that the measuring system of bio-signal of the plant being proposed in this study can be useful to show the Characteristics of the plants.

• Journal of the Korean Solar Energy Society
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• v.34 no.3
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• pp.89-97
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• 2014

Recently design standard for energy-saving in apartment buildings has been consolidated gradually on the basis of evaluation and certification standards of energy efficiency of buildings, the energy-saving policy of building at home and abroad. Performance criteria for thennal insulation as well as fenestration has been progressively enhanced, and performance criteria for ventilation and airtightness of the building have also been re-developed. Therefore, heating and cooling load characteristics of the apartment building can be changed. For the design of the upcoming heating and cooling equipment in apartment buildings, it is necessary to evaluate the heating and cooling load characteristics according to the design strategies for energy saving in apartment buildings. As a result, in this study, it is intended to use as a resource for analyzing the impact that the adoption of energy-saving design variables for each of the apartment buildings, to predict the heating and cooling load characteristics in the apartment building.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.12
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• pp.828-836
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• 2010

The drying is a process that involves coupled and simultaneous heat and mass transfer. When a wet solid is subjected to thermal drying, two processes occur simultaneously. Drying is classified according to heat transfer characteristics in terms of conduction, convection and radiation. In thermal drying, radiation is easier to control than conduction and convection drying and involves a relatively simple structure. In this study, we measured energy consumption, surface hardness of paint and surface gloss with variation of surface temperature of drying materials and drying time. Drying characteristics and energy consumption between heating panels and hot air heating have been presented. The present study shows that a dryer using heating panels is more effective than a hot air dryer from the viewpoint of energy conservation. The hot air dryer, however, was not optimized and more studies on various parameters related to drying will need to be investigated for definite comparison of drying characteristics of the dryers. The result, even if limited, would present the effective availability of paint drying.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.2
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• pp.69-74
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• 1999

This paper presents about a example of circuit design and characteristics of proposed circuit in the case of adopted the high frequency resonant Inverter of SEPP type using ZVS(Zero-Voltage-Switching) to the Induction heating load. The soft switching technology known as ZVS is used to reduce turn on and off loss at switching. Also, this paper realizes quantitative circuit analysis which has change the equivalent of Induction heating load to the electric circuit. According to the calculated characteristics value, a method of the circuit designs and operation characteristics of the Inverter is proposed. In addition, this paper proves the propriety of theoretical analysis through the experiment. The proposed inverter shows it can be practically used as power source system for induction heating Jar etc.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.1
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• pp.18-25
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• 2005

We have researched 10,811 schools to evaluate the characteristics of school buildings and the conditions of heating and cooling systems at the elementary, middle and high school levels. Air conditioning systems in school buildings are related to school scale, and 35% of the researched schools have less than 10 air conditioned classrooms among all of the schools in Korea. The LOADSYS is used to grasp the characteristics of school buildings heating and cooling load. From the results of this work, the heating load differs by nearly 24% between Seoul and Busan, but other than that there are not so many serious regional differences. Almost 85.4% of the classrooms are equipped with heating facilities and 6.9% of them are equipped with heating and cooling facilities. As a result, it is necessary to make improvements in 31.8% of the classrooms using only heaters and 14.6% of the classrooms not equipped with HVAC. The survey shows that there is a wide gap in the heating equipment status of the classrooms according to the region and school district.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.1
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• pp.147-155
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• 1999

In this work, the defrosting characteristics of PTC heating sheet used as a defrosting heat source of fin-tube heat exchanger in a refrigerator have been experimentally compared with those of conventional electric heater. It is found that the characteristics of water draining rate with defrosting time show smoothly oscillating pattern when PTC heating sheet is used, and the drained water is completely melted. The defrosting efficiency of the PTC heating sheet is about 75%, which represents about 25% higher than that of the electric heater. A reduction of defrosting time and an increase of defrosting efficiency may be obtained by improving the arrangement of heating elements of the heating sheet. It is shown that the defrosting time of PTC heating sheet increases linearly with the amount of frost, however the defrosting efficiency is nearly constant. In the application to the refrigerating system, one should notice the fact that the defrosting performance of PTC heating sheet may be defraded due to the repeated operations.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.2_2
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• pp.271-278
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• 2022

The solar energy has been widely used to reduce the fossil fuel and prevent the environmental pollution. The renewable energy including solar heat tends to spread due to carbon neutrality for main country of the world. Targets of solar collector are usually acquisitions of hot water or hot air. Especially, air-heating collector using solar heat is known as the technology for obtaining hot air. This study aims to investigate of characteristics of thermal flow when the hot air by air-heating collector using solar heat flows inside of indoor space. The thermal flow of heating indoor space was simulated using ANSYS-CFX program and thus the behaviors of hot air in indoor space were evaluated with standard k-𝜀 turbulence model. As the results, as the inlet velocity was increased, the behaviors of hot air became simple, and temperature range of 25~75℃ had almost no effect on behavior of flow. As the inlet temperature was increased, the temperature curve of indoor space from bottom to top was changed from linear to quadratic. Furthermore, it was confirmed that inlet velocity as well as inlet temperature also should be considered to heat indoor space equally by air-heating collector using solar heat.

• Journal of Soil and Groundwater Environment
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• v.11 no.1
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• pp.45-53
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• 2006

This study was performed to evaluate the heating characteristics of soils for the application of electrical resistance heating process combined with soil vapor extraction. Laboratory tests were conducted to find out optimum heating conditions by the adjustment of electrical supply and electrode. Results show that fine soil particles are more efficient for electrical heating. As water content of soil increases, more efficient electrical heating is observed. However, as the soil is saturated with water above the soil porosity, decrease in the heating efficiency is observed. The higher the voltage, is and the shorter the distance between the electrodes is, the better the heating efficiency is. The soil contaminated by fuel is also more efficient than non-contaminated soil in electrical resistance heating. From the relationship between the intial electrical current and the conductivity obtained in this study, soil temperature by electrical heating can be estimated.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.650-655
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• 2009

In this study, a consumer willingness to pays for residential heating systems are estimated by economic valuation method. The major Korean residential heating systems in apartments are central heating system (CH), district heating system (DH), and individual heating system (IH). However, DH and IH systems are adopted in newly constructed apartments. Each heating system has own characteristics which residents can identify and value. 700 households in apartment were surveyed to analyze the preference of the residential heating systems and to estimate willingness to pay. We find that the households in DH system are more satisfied with their heating system than the households in other systems overall and that consumers prefer an apartment with DH system than with IH system and the willingness to pay for IH system is less than DH system. The results indicate that DH system has the relative premium which may be caused by the safety and the convenience to manage the system.