• 한국수소및신에너지학회논문집
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• 제26권1호
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• pp.64-70
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• 2015

Organic Rankine cycle (ORC) is an useful cycle for power generation system with low temperature heat sources ($80{\sim}400^{\circ}C$). Since the boiling point of operating fluid is low, the system is used to recover the low temperature heat source of waste heat energy. In this study, a ORC with R134a is applied to recover the waste energy of condenser of coal fired power plant. A system model is developed via Thermolib$^{(R)}$ under Simulink/MATLAB environment. The model is composed of a refrigerant heat exchanger for heat recovery from coal fired condenser, a drum, turbine, heat exchanger for ORC heat rejection, storage tank, water recirculation pump and water drip pump. System analysis parameters were heat recovery capacity, type of refrigerants, and types of turbines. The simulation model is used to analyze the heat recovery capacity of ORC power system. As a result, increasing the overall heat transfer coefficient to become the largest of turbine power is the most economical.

• 전력전자학회논문지
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• 제12권5호
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• pp.386-393
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• 2007

본 논문에서는 CIM(Current Injection Method)을 이용한 charge-pump방식의 plasma backlight용 고압 inverter회로를 제안한다. 고압 inverter에서 에너지 회수회로의 채용은 새로운 시도로서 에너지회수 이외에도 noise에 의한 시스템의 불안정성과 방전안정화에 기여하고 있다. charge-pump방식으로 스위치류의 내압을 저감하므로 cost면에서 매우 유리한 조건을 확립하였으며 CIM(Current Injection Method)방식의 적용으로 high speed 에너지 회수를 가능하게 하였다. 그리고 제안회로의 동작을 모드별로 해석하였으며, 실제 32" 패널에 적용하여 실험함으로써 제안한 회로의 유용성을 입증하였다.

• 대한기계학회논문집B
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• 제34권7호
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• pp.715-720
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• 2010

본 논문은 고분자전해질막 연료전지의 공기 공급을 위해 전기침투현상에 기반을 둔 공기 공급 방법을 제안하고 이를 실험적으로 평가하였다. 작동 유체의 구동을 위해서 전기침투펌프를 낮은 주파수의 교류 전기장에서 사용하였다. 작동 유체는 유연한 막에 의해 막 밀봉하였고, 막의 움직임에 의해 연료전지 내로 공기를 공급하였다. 본 연구에서는 전기침투현상 기반 공기펌프를 사용하여 연료전지의 공기 공급을 성공적으로 설명하였다. 펌프의 출력은 연료전지에서 생성되는 출력을 초과하였지만, 본 논문에서는 펌프의 출력 당 연료전지의 출력비를 줄이기 위한 몇 가지 방법들에 대해 설명하였다.

• 한국통신학회논문지
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• 제29권5A호
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• pp.484-491
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• 2004

L-band EDFA는 작은 평균밀도 반전율에서 동작하기 때문에 C-b란d에서 상대적으로 높은 흡수율로 인해 펌프 효과를 가지게 된다. 본 논문에서는 980nm의 펌프 입력 광 파워, C-band 펌프 파장 및 입력 광 파워에 따라 펌프 효과에 대해 논하고자 한다. 즉, C-band 펌프광의 흡수 또는 후방 자연방출광의 흡수라는 두 가지 다른 메카니즘을 통해 펌프 효과를 야기 시키게 된다. 또한 동일한 소 신호 이득 조건 하에서 L-band 신호 입력 광에 의한 포화 특성 (포화 광출력, 잡음지수에 있어서 장파장의 C-band 펌프가 양호한 것으로 나타난다. 전광 고정이득 L-band EDFA에서 C-band발진의 효과를 검토한 결과 L-band발진에 비해서 개선된 특성은 없는 것으로 나타난다.

• 동력기계공학회지
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• 제22권6호
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• pp.58-66
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• 2018

The use of external gear pumps is an effective way to achieve adequate performance at low cost when composing hydraulic systems. The biggest drawback, on the other hand, is the accompanying noise. Gears of continuous contact shape are actively used for the pump recently. The continuous contact shape must be the helical type due to the nature of the gear pump that is driven only by the drive gear. In this paper the theoretical shape of continuous contact gear is analyzed using simple rack shape of straight lines and two circular arcs. Using such geometry, the theoretical equation will be developed by envelope curves according to the conjugate gear shape rules. After checking the validity of the theory by the shape of gear rules, the grinding shape was also developed. The 3D shapes using equation can be also drawn. It was also shown that contact ratio and radius of curvature are easily developed by the theoretical equations.

• Journal of Advanced Marine Engineering and Technology
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• 제39권3호
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• pp.211-216
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• 2015

차체중량이 90 ton인 초대형 유압굴삭기에서는 유압시스템의 효율향상을 통한 연비개선을 위해서 유압펌프 구동용 기어박스(hydraulic pump driving gear box)를 사용하여 다수(3~6개)의 펌프를 병렬로 장착하여 사용한다. 펌프 구동 기어 박스는 굴삭기의 대형엔진과 연결되는 입력 축 1개로 기계적 동력인 회전수와 토크를 공급받아 고압펌프와 저압펌프에서로 다른 기계적 출력을 공급하게 된다. 따라서 펌프 구동 기어박스는 굴삭기의 대동맥과 같으며, 엔진이 가동되는 시간동안 지속적으로 펌프를 구동함으로서 장 수명이 요구된다. 본 연구에서는 큰 시험동력(600kw)이 요구되는 수명평가에서 에너지절감을 위한 전기 회생식 시험 장비를 구축하여 높은 에너지 절감과 수명시험을 수행하면서 기어박스의 마모 특성을 분석하는 방법으로 윤활유 오염 입자 분석과 기어파손 유무를 검증하는 방법으로 진동분석 방법을 사용하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.287-290
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• 2006

Orbiter mechanism has been applied to vacuum pump design for small oxygen generator where low vacuum of about 200mmHg is required. Performance of the designed vacuum pump has been numerically investigated: calculated volumetric and adiabatic efficiencies were 69.7% and 83.9%, respectively for leakage clearance of $10{\mu}m$. Total efficiency of the orbiter vacuum pump was 77.5%. At the shaft speed of 1700 rpm suction displacement volume of 6.3cc provided discharge flow at the rate of 2.3 liter/min with power consumption of 10.1Watt. Torque variation of the orbiter pump was only about 20% of that of diaphragm pump.

• 한국유체기계학회 논문집
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• 제9권5호
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• pp.28-35
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• 2006

Orbiter mechanism has been applied to vacuum pump design for small oxygen generator where low vacuum of about 200 mmHg is required. Performance of the designed vacuum pump has been numerically investigated: calculated volumetric and adiabatic efficiencies were 69.7% and 83.9%, respectively for leakage clearance of $10{\mu}m$. Total efficiency of the orbiter vacuum pump was 77.5%. At the shaft speed of 1700 rpm suction displacement volume of 6.3cc provided discharge flow at the rate of 2.3 liter/min with power consumption of 10.1Watt. Torque variation of the orbiter pump was only about 20% of that of diaphragm pump.

• 설비공학논문집
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• 제11권2호
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• pp.193-204
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• 1999

Performance of a variable-speed, roller-type vane compressor was evaluated at low evaporating temperature. First, an experimental investigation was conducted to examine the performance variation as functions of both outdoor temperature and rotating speed. For this purpose, a typical heat pump was implemented as a test apparatus to measure mass flow rate and power input. Secondly, computational investigations corresponding to the heat pump test conditions were performed to predict compressor performance using ORNL Map-Based compressor model. Results obtained from the heat-pump experiments showed that both mass flow rate and power consumption were sensitively dependent on both evaporating temperature and compressor speed as was predicted from the computational results. From the comparisons of both experimental and computational results, it was well recognized that the ORNL model was subjected to larger error in the accuracy of prediction as outdoor temperature decreased. When the outdoor temperature was above $-5^{\cire}C$, errors of predicted values corresponding to both mass flow rate and power consumption were estimated as $\pm$10% and $\pm$ 15%, respectively. Finally, it is suggested that the ORNL model needs to be re-evaluated if compressor map data tested below $-5^{\cire}C$(in evaporating temperature) are available.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.942-949
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• 2014

We studied about the rotor design change using a Ferrite ring magnet to reduce material cost in the condition of the same stator core design. However, this design direction has many weak points such as the decrease of BEMF, the low maximum output, the irreversible demagnetization characteristics of a permanent magnet and so on. In order to mitigate such disadvantages, an optimization design of the BLDC motor has been developed by changing each design parameter and by improving the electromagnetic structure. In the proposed water pump SPM BLDC motor using Ferrite magnet, the outer and inner diameter of stator is fixed to the value of the conventional IPM BLDC motor using Nd-Fe-B magnet. The design specification requirements should be satisfied with the same output power and efficiency characteristics in the same dimension. As a result of this study, the design comparison results considering driving performances and material cost are represented. Through the actual experiment with the prototype of the designed motor, the simulations results are verified.