• 설비공학논문집
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• 제19권11호
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• pp.743-750
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• 2007

In this study, ice slurry generator using air cylinder was designed and manufactured to investigate the heat transfer characteristic of the ice slurry generator. The ice slurry generator has the same shape as the shell-and-tube type heat exchanger. Refrigerant is flowing in the shell side and ethylene glycol solution in the tube side. The experiment was conducted on performance of ice slurry generator using air cylinder with standard condition and the results are plotted on the time scale. The experimental tests on the various concentration of ethylene glycol solution, the various solution velocity in the tube side and the various tube size have been carried. For the above experimental conditions, ice making characteristics of the ice slurry generator are evaluated in terms of the overall heat transfer coefficient. And the experimental results show that the overall heat transfer coefficient of the system is increased as the tube size and the concentration of ethylene glycol decreases.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.1974-1979
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• 2007

In this study, Ice slurry generator heat transfer characteristics are experimentally investigated for the ice slurry generating system with scraper which is pneumatically operated. The ice slurry generator has the same shape as the vertical double tube type heat exchanger. Refrigerant is flowing in the outside tube and ethylene glycol solution in the inside tube. Refrigerant and solution water are parallel flow type which entering bottom of generator and leaving top of generator. The experimentations are conducted under the various test conditions such as compressor speed and cooling water temperature. For the above experimental conditions, heat transfer characteristics of the ice slurry generating system are evaluated in terms of the overall heat transfer coefficient and the heat transfer rate. And the experimental results show that the heat transfer rate of the system is increased as the compressor speed increases and the cooling water temperature decreases.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.144-149
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• 2006

In this study ice making characteristics are experimentally investigated for the ice slurry generating system which is pneumatically operated. The experimentations are conducted under the various test conditions such as chilled water inlet temperature, aqueous solution concentration, flow rate of cooling water, scraper pitch and frequency of cylinder stroke. For the above experimental conditions, ice making characteristics of the slurry ice generating system are evaluated in terms of the overall heat transfer coefficient, heat transfer rate and the amount of slurry ice generation. And the experimental results show that the heat transfer rate of the system increases as the flow rate of cooling water solution increases and the concentration of ethylene glycol and inlet temperature of chilled water decreases.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.984-989
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• 2009

The present study has been conducted to predict the temperature distribution in the core of the scraper type ice generator. The analytic model was simplified as the flow in the annular type cylinder, which had an inside wall moving in axial direction due to the rotation of screw and a fixed outside wall. The governing equations were arranged by the method of separation of variables. The results corresponded to the exact solutions of the Bessel function. The qualitative results such as general characteristics of heat transfer in annulus flow from outer cylinder wall to the inside wall were obtained. However the amount of the heat transfer was underestimated as low as $1/5{\sim}1/6$ of the designed value.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2004년도 하계학술발표 논문집
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• pp.84-84
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• 2004

• Journal of Magnetics
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• 제20권2호
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• pp.148-154
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• 2015

48-V ISG (Integrated Starter Generator) system has attracted attention to improve the fuel efficiency of ICE (Internal Combustion Engine) vehicle. One of the key components that significantly affects the cost and performance of the 48-V ISG system is the motor. In an ISG motor, the core and copper loss make the motor efficiency change because the motor has a broad driving operated range and more diverse driving modes compared with other motors. When designing an ISG motor, the selection of an electrical steel sheet is important, because the electrical steel sheet directly influences the efficiency of the motor. In this paper, the efficiency of the ISG motor, considering core loss and copper loss, is analyzed by testing different types of electrical steel sheets with respect to the driving speed range and mode. Using the results of a finite element method (FEM) analysis, a method to select the electrical steel sheet is proposed. This method considers the cost of the steel sheet and the efficiency according to driving mode frequency during the design process of the motor. A wound rotor synchronous machine (WRSM) was applied to the ISG motor in this study.

• International Journal of Automotive Technology
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• 제8권6호
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• pp.781-790
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• 2007

Hybrid electric vehicles(HEV) combined with more than one power sources have great potential to improve fuel economy and reduce pollutant emissions. The Integrated Starter Generator(ISG) HEV researched in this paper is a two energy sources vehicle, with a conventional internal combustion engine(ICE) and an energy storage system(batteries). In order to investigate the potential of diesel engine hybrid electric vehicles in fuel economy improvement and emissions reduction, a Dynamic Programming(DP) based supervisory controller is developed to allocate the power requirement between ICE and batteries with the objective of minimizing a weighted cost function over given drive cycles. A fuel-economy-only case and a fuel & emissions case can be achieved by changing specific weighting factors. The simulation results of the fuel-economy-only case show that there is a 45.1% fuel saving potential for this ISG HEV compared to a conventional transit bus. The test results present a 39.6% improvement in fuel economy which validates the simulation results. Compared to the fuel-economy-only case, the fuel & emissions case further reduces the pollutant emissions at a cost of 3.2% and 4.5% of fuel consumption with respect to the simulation and test result respectively.

• 한국태양에너지학회 논문집
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• 제25권2호
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• pp.63-69
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• 2005

This study is the survey of a transition procedure of building services systems(heat source, HVAC, water supply) through the survey of existing office buildings, building design documents. The preference & major consideration of system selection is the engineer's opinions. The results of this survey can be used in selection of building services system design. In this survey, "Hot & cold water generator system" and "single duct CAV+FCU system", "Elevated water tank system" are selected. The most important consideration in system selection is the energy saving in heat source system, and comfort in HVAC system, and water pressure in water supply system. They prefer "steam boiler+absorption chiller system" for heat source system, "steam boiler+ice thermal storage system", "hot & cold water generator system", "district heating+absorption chiller system" : "single duct CAV+FCU system" and "single duct VAV+convector system" for HVAC system: and "booster pump system" for water supply system.

• 한국통신학회논문지
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• 제37C권9호
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• pp.811-820
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• 2012

GNSS 신호는 구조가 개방되어 있을 뿐만 아니라 수신 신호 세기가 미약하여 전파교란에 취약하다. 이에 따라 전파교란에 대한 영향 분석 및 대응 기법에 대한 연구의 필요성이 증대되고 있다. 본 논문에서는 실제 전파교란 환경과 유사한 환경에서의 전파교란 영향 분석을 위하여 6가지 전술 환경에 대한 전파 전파 모델과 이동체의 수신환경을 고려한 동체 차단 모델을 설계 하였다. 전파전파 모델은 도심지역, 농촌지역, 수풀지역, 해안지역, 황무지, 눈/얼음 지역에 대해서 Two-ray 모델을 이용하여 설계 하였다. 동체 차단 모델은 안테나가 이동체에 의하여 받는 영향과 사용자가 직접 입력한 안테나 패턴을 이용하여 모델링하였다. 전파교란이 없는 정상 환경과 전파교란 환경에 대하여 이동체의 수신환경을 고려한 GNSS 신호 생성기의 출력은 상용수신기(NordNav)를 이용하여 검증 하였다. 정상 환경에서는 사용자의 항법 성능이 상용 H/W 신호 생성 시뮬레이터(STR4500)과 유사한 것을 확인하였다. 전파교란 환경에서는 이동체 위치에 따른 동체 차단 효과 및 전파교란 신호에 의한 GNSS 신호 획득 및 추적 손실이 정확히 반영됨을 확인 하였다.

• 통합자연과학논문집
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• 제7권3호
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• pp.214-218
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• 2014

The main objective of this study is to analyse the influence factors of snowfall enhancement by glaciogenic seeding in a mountainous area. Twenty-five seeding experiments have been conducted during the period of February to April 2010. To use two rates seeding experiments (SR1: $1.04g\;min^{-1}$, SR2: $2.08g\;min^{-1}$) have been tested to get an appropriate ratio for snowfall enhancement at Daegwallyeong area. The conditions of seeding are able as followings: surface temperature <$0^{\circ}C$, wind speed <5 m/s, wind direction between 0 and $130^{\circ}$. The experiment results indicated that in the case of SR1 was more effective than SR2. The number of small ice particles below 1.0 mm was increased during seeding period measured by PARSIVEL disdrometer near generator. Most of snowfall enhancement by seeding was observed the inflow of the easterly wind blew in toward Gangwon regions from the East Sea and the supersaturated supercooled liquid water due to orographic effect.