• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.147-151
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• 2002

Cross flow fan system is widely used for various applications, especially for the air-moving device of heaters, air-conditioners, and air-curtains. Although there are efforts for the optimization of cross-flow fan flow path with different methods of approach, it is still being investigated by many researchers through experimentally and/or theoretically, because the flow pattern of the cross flow fan is not stereotyped. This paper presents some results from numerical experiments for the optimization of the flow path through a cross-flow fan to be applied to indoor wall-mounted room heater. Two dimensional analysis has been applied to a specific fan system including inlet and diffuser outlet. Flow characteristics art presented and discussed for two different flow path at three different operating conditions represented by rotational speed(800, 1,000, 1,200 rpm) of the In. According to the simulated results for the specific fan system under consideration, it could be found that the flow pattern resembles each other at different rotational speed (to say from 800 rpm to 1,200 rpm) for a fixed flow path, while the secondary flows mostly absorbs the speed effects. By changing the flow path significant increase in volume flow rate is estimated upto 2.65 at the same rotational speed. According to the present experience, fan flow path design can be performed more efficiently by incorporating this type of numerical experiments combined with the model tests.

• 설비공학논문집
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• 제21권9호
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• pp.527-535
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• 2009

The aim of this study is to investigate the daily heating performance of ground source multi-heat pump system with vertical single U-tube type GLHXs, which were installed in a school building located in Cheonan. Daily average COP of heat pump unit on Jan. 12th, 2009 at heating mode was lower than it on Nov. 10th, 2008 and Dec. 15th, 2008, because of lower EWT of the outdoor heat exchanger and relatively smaller size of condenser and evaporator. But, the system COP on the former was higher than it on the latter because ground loop circulating pump was operated in rated speed. It is suggested that the new algorithms to control the flow rate of secondary fluid for GLHX according to load change have to be developed in order to enhance the performance of the system COP.

• 한국컴퓨터정보학회논문지
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• 제15권8호
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• pp.157-161
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• 2010

대도시 대기오염의 대부분이 자동차 배출가스에 의해서 이루어지고 있으며, 세계적으로 환경오염에 대한 규제수준이 점차 강화되고 있어 저공해의 환경 친화적인 자동차의 개발과 보급이 요구되고 있으며, 고유가 시대에서 이미 국내 외에서 개발 양산중인 하이브리드 자동차의 급속한 시장 확대가 예상된다. 하이브리드 자동차에서 전기에너지를 저장하는 배터리는 가장 중요한 구성요소 중 하나이며, 하이브리드 자동차용 배터리(전기에너지를 저장하는 2차 전지)는 순간적으로 에너지를 방출하는 특성 즉 고출력 특성이 일차적으로 요구되며, 자동차 부품으로서의 신뢰성과 내구성이 확보되어야 한다. 따라서 본 논문에서는 하이브리드 자동차에 장착되는 2차 전지의 충 방전 상태를 안정적으로 모니터링 하는 시스템과 전지의 충 방전 성능을 극대화할 수 있고 충 방전 제어가 가능한 실시간 충 방전 모니터링 시스템을 제안하였다. 논문에서 새롭게 제안한 감지부와 제어부로 구성되는 충 방전 시스템은 하드웨어 및 소프트웨어 모듈과 실시간으로 셀 배터리의 충 방전 상태를 효율적으로 제어할 수 있으며 데이터베이스와 통신모듈을 기반으로 원격제어가 가능한 시스템이다.

• 한국항공운항학회지
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• 제25권3호
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• pp.89-100
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• 2017

In order for the international aviation community to efficiently and safely manage the gradual increase of air passenger demand, direction suggestions of airport traffic prediction based on future airport capacity requirements, airport design and infrastructure establishment is utilized by airport traffic data that is m comparable internationally. It is a global trend to pursue more efficient airport operating system structure to accept air passenger demand through more realistic comparable data in order to escape from the structure of reckless airport establishment and infrastructure composition based on passenger demand predictions referring to simple statistical data that has existed in the past. This study aimed to seek effective operational measures for the New Jeju airport scheduled to be opened in 2025 by time-series analysis. This study also analysed airport operation strategies, air traffic distribution strategies, cargo volume increase rates and its effectiveness of airports adopting the multi-airport system that have similar operational practices and geographical conditions. This study sought the most appropriate multi airport system application measures for New Jeju airport to promote efficiency and international competitiveness.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.916-921
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• 2007

In this paper, the inductive power collector using electromagnetic induction for vehicle such as the electric railway vehicle system is suggested and some ideas for power collector design to improve the power transfer performance are presented. The inductive power of secondary part is related to amount of linked flux to secondary part by the length of air-gap, which is expected by such a system parameter as mutual inductance. This paper will study for the transfer characteristic of power from input to output and equation including mutual inductance. And also, effect of leakage inductance variation of inductive power collector according to structure of winding was considered.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1259-1260
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• 2007

In this paper, the inductive power collector using electromagnetic induction for vehicle such as the electric railway vehicle system is suggested and some ideas for power collector design to improve the power transfer performance are presented. The inductive power of secondary part is related to amount of linked flux to secondary part by the length of air-gap, which is expected by such a system parameter as mutual inductance. This paper will study for the transfer characteristic of power from input to output and equation including mutual inductance. And also, effect of leakage inductance variation of inductive power collector according to structure of winding was considered.

• 설비공학논문집
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• 제12권5호
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• pp.446-475
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• 2000

Performance of a water-to-water multi-type heat pump system using R22 has been experimentally investigated. Total refrigerant flow rate was adjusted with a variable speed compressor and the refrigerant flow rate for two indoor units were controlled by electronic expansion valves. Evaporator outlet pressure of refrigerant and indoor unit outlet temperatures of secondary fluid were selected as controlled variables. Experiments were carried out for both cooling and heating modes using PID control method. Results show that the multi-type heat pump system can be adequately controlled by keeping control gains at certain levels for various operating conditions.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.794-799
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• 2005

In this paper, the inductive power collector using electromagnetic induction for the PRT(Personal Rapid Transit) system is suggested and some ideas for power collector design to improve the power transfer performance are presented. The proposed the inductive power collector is used for the PRT system, which has a large air-gap and demands a large electrical power capability. But, low output power is generated due to a loosely coupled characteristic of the large air-gap. Therefore, double layer construction of secondary winding. which was divided in half to increase both output current and output voltage was suggested. Also, model of power collector and parallel winding structure are presented, in addition, the performance of inductive power collector to alignment condition between the primary power line and the inductive power transformer was verified by computer simulation of 2kW model.

• 설비공학논문집
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• 제6권3호
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• pp.291-301
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• 1994

This paper presents the promotion of heat transfer through the use of wire-mesh screens. To improve heat transfer in an impingement water system, the wire-mesh screens are installed between the nozzle-to-heater surfaces. When the wire-mesh screens are not employed, this report exhibits the maximum heat transfer and the secondary maximum value at the stagnation point. But in case of using the wire-mesh screens, the transfer coefficient value of maximum heat exists at the stagnation point, and the second maximum value doesn't occur. Therefore, the heat transfer is more improved than 4~6 times that of the mean Nusselt numbers of simple water jet system, Also, within the region presented in this study, the heat transfer was promoted by using the wire-mesh screens at the stagnation point ; thus, the heat transfer was more increased than 6-7. 5 times that of simple water jet system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.753-758
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• 2000

Heat engine and fluid machinery in the plant have to linked with various ducts network and the corresponding design have to be concerned about effectiveness and stability of system of plant. To optimum control and design system concerning stability, economization, operating effectiveness we have to exact analysis flow properties of a duct applying to fluid machinery, heat exchanger, cooling machine, air conditioning equipment. therefore, it is necessary to research the duct, heat transfer equipment, for increasing overall effectiveness of air conditioning system by suggesting basic data of the duct resulting from organic research. So we can contribute to technical development of the duct. In case of speeding up the flow rate of the duct, lots of wave velocity components are occurred the value of boundary layer resulting from developing the boundary layer at both walls of duct.