• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.115-115
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• 2011

Biodiesel (BD) was made from animal-fats reacting with methanol and potassium hydroxide in the laboratory. The biodiesel made in the laboratory was sent to K-petro, the government agency, to inspect the quality of animal-fats biodiesel, of which generally the quality was acceptable for heating oil for agricultural hot air heater. Kinematic viscosity and calorific values of the biodiesels were measured. BD20(K), kerosene based biodiesel, showed 18cSt at $-20^{\circ}C$. It seems that BD100 can not be suitable for heating fuel under some temperature. As BD content increased calorific value decreased, up to 40,000J/g for 100% BD, while light oil calorific value was 45,567J/g, showing difference of 5,567J/g, about 12% difference. Several different fuels, BD20, BD50, BD100 and light oil, were prepared and tested for fuel combustion qualities for agricultural hot air heater and their combustion performances were compared and analyzed. Flame dimensions of biodiesels and light oil were almost same shape at the same combustion condition in the burner of the hot air heater. Generally $CO_2$ amounts of BDs are greater than light oil. But,the differences are so small that it is hard to tell there was significant difference existed between the BDs combustion and light oil.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1290-1295
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• 2006

The 120 meters high pressure feedwater heater drain piping in nuclear power plant had been suffered by excessive vibration from the beginning of power generation. As time goes by, the piping vibration was beyond the allowable limit and an appropriate countermeasure was required to prevent the fatigue failure of the pipeline from the abnormal vibration. In this study, the vibrational characteristics of high pressure feedwater heater drain piping and the countermeasure for abnormal vibration were investigated. Among the several vibration reduction methods, the piping layout changed by making the smooth pipeline was applied to the high Pressure feedwater heater drain piping in nuclear Power plant. Applying the countermeasure, the vibration level was found to reduce over 54 percents and was satisfied under the allowable velocity at the full-power operation condition.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.11 no.4
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• pp.22-27
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• 2015

Quality characteristics of Shiitake mushroom using two types of dryers, energy-efficient heat pump hot-air dryer and electric heater hot-air dryer were compared. Energy consumed during drying by heat pump hot-air dryer and electric heater hot-air dryer were 22.8 kWh and 28.9 kWh, respectively. Total polyphenol content of heat pump hot-air dryer and electric heater hot-air dryer after drying were $290.55{\pm}10.56ppm$ and $192.99{\pm}6.53ppm$, respectively. No differences were observed between dryers in reconstitution rate and browning ratio after drying. Also, there were no differences between dryers in color value and ${\Delta}E$ value after drying. Shiitake mushroom drying at $45^{\circ}C$ by heat pump hot-air dryer was proved to be more efficient in energy consumption than by electric heater hot-air dryer.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1669-1674
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• 2017

In this study, We have discussed the development of a diagnostic device to detect and prevent electrical fire due to the arc caused by contact failure and partial disconnection at the connection part of the three-phase electric heater wiring used in the industrial field. The arc caused by contact failure and partial disconnection at the connection part of the electric heater shows a change in the current effective value. Therefore, it is possible to determine whether there exists a defect by analyzing the current unbalance factor and the number of current fluctuations with the diagnostic apparatus. The three-phase unbalanced heater is considered to be capable of determining defects through periodic measurement and trend analysis of the current unbalance factor. It is also expected that this device can be used not only for electric heaters but also for detection of defects in wiring and connections of electrical equipment having a characteristic of constant load current.

• Journal of IKEEE
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• v.18 no.2
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• pp.185-191
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• 2014

In this paper, we have implemented the low temperature fluidity test system with the composited package fuel heater, which has tested the low temperature fluidity and start time to evaluate the performance. Then we have compared the separation and the unified fuel heater type at $+20{\sim}-30^{\circ}C$. Also, we have tested the flowing pressure and start time, power consumption of heater. By comparing the performance with several condition, the experimental results obtain an improved start time of 23% and low temperature fluidity of 19%.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2664-2669
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• 2008

Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damange, which will increase as operating time progresses. Several nuclear power plants in Korea have experienced wall thinning damage in the area around the impingement baffle-installed downstream of the high pressure turbine extraction stream line- inside number 5A and 5B feedwater heaters. At that point, the extracted steam from the high pressure turbine is two phase fluid at high temperature, high pressure, and high speed. Since it flows in reverse direction after impinging the impingement baffle, the shell wall of the number 5 high pressure feedwater heater may be affected by flow-accelerated corrosion. This paper describes operation of experience and numerical analysis composed similar condition with real high pressure feedwater heater. This study applied squared, curved and new type impingement baffle plates to feedwater heater same as previous study. In addition, it shows difference of pressure distribution and value between single phase and two phase based on experience and numerical analysis.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.416-422
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• 2007

The application analysis of bubble pump on the domestic solar water heater system is presented. The system investigated in this study is a passive device, self pumping and self regulating. It was test to use the bubble pump on solar water heater system. The test experiment has been taken on the existed vacuum tube about the efficiency, working fluid temperature and pressure and circulated power. In order to check the working temperature and working pressure effectively, the bubble pump was test separated from the solar water heater. The equipment consists of the bubble pump, heater and heat exchanger. The main structure of bubble pump was design depend on the character of two phase flow. The complete system was instrumented to measure pressures, temperatures and their relationship with the solar radiation intensity. The theory analysis of design bubble pump has been given and the experiment result analysis has been included in the paper.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.9
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• pp.483-495
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• 2009

Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damange, which will increase as operating time progresses. Several nuclear power plants in Korea have experienced wall thinning damage in the area around the impingement baffle-installed downstream of the high pressure turbine extraction stream line-inside number 5A and 5B feedwater heaters. At that point, the extracted steam from the high pressure turbine is two phase fluid at high temperature, high pressure, and high speed. Since it flows in reverse direction after impinging the impingement baffle, the shell wall of the number 5 high pressure feedwater heater may be affected by flow-accelerated corrosion. This paper describes operation of experience and numerical analysis composed similar condition with real high pressure feedwater heater. This study applied squared, curved and new type impingement baffle plates to feedwater heater same as previous study. In addition, it shows difference of pressure distribution and value between single phase and two phase based on experience and numerical analysis.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.618-625
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• 2005

This paper has achieved that an optimal design and experiments of heater and cathode of electron gun that serve to embody high current density in CRT display. For the high brightness, high resolution and larger size in CRT display, high current density of electron gun is indispensible. An Impregnation style cathode is used, and must heighten operating temperature of heater to get high current density for this, it is proportional hereupon and power dissipation increases. In this paper, to get low power cathode with high current density, There are produced and tested sample that differ lead type of heater, coating method, the pitch and number of winding of the first and second coiling in the heat emission area for the low power design of high current density cathode heater in this paper.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.484-489
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• 1999

This paper deals with the design and fabrication of a heater-trigger type high-Tc superconducting power supply system, and characteristics have been analyzed through experiments. The high-Tc superconducting power supply consists of two heater trigger and electric magnet, and YBCO superconducting bulk. In this experiment, 0.6T class magnet and dc 2.3A heater current are used, and the current-pumping characteristics have been analyzed with computer aided sequence control system. Hall sensors are installed on the YBCO bulk and in the center of iron core in order to analyze the effect of the flux-pumping on the system with when magnet flux changes its value. In this experiment, maximum pumping-current has been achieved to about 6.6 amps.