• 한국태양에너지학회 논문집
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• 제34권1호
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• pp.58-63
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• 2014

A vertical closed loop ground source heat pump (GSHP) is used to produce heat from the low-grade energy source such as the outside air and ground source. It is known that a heat pump system type has better efficiency comparing to the electric heating system. This study only demonstrates that the vertical closed loop GSHP system is a feasible choice for space cooling of air conditioning. The coefficient of performance (COP) is the ratio of heat output to work supplied to the system in the form of electricity. For the vertical closed loop GSHP system in a cooling mode, the COP is the most commonly used way for judging the efficiency. For the purpose of this experiment, vertical closed loop GSHP system was installed in the laboratory and the experiment was executed. As a result, an average COP of vertical-closed loop GSHP system was 3.62 when the outside average temperature was $33^{\circ}C$.

• 한국태양에너지학회 논문집
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• 제25권4호
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• pp.69-76
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• 2005

The performance of water-to-water heat pump system coupled with the ground source vertical heat exchanger is presented in this paper. The CAP program of Florida Heat Pump Co. is used to predict the heat pump performances while the EED program calculates the borehole fluid temperature. It is shown that COPH increases with decreasing the temperature of output water for the operation of heating mode and COPR increases with increasing temperature of output water for the operation of cooling mode. The value of specific heat extraction rate must be moderate to insure the reasonable installation cost of borehole system. With $1^{\circ}C$decrease of $T_{wo}$ the average COPH increase is estimated as about $0.06/^{\circ}C$(for $T_{wo}\;=\;45{\sim}60^{\circ}C$ range) while with $1^{\circ}C$ increase of $T_{wo}$ the estimation of COPR increase is about $0.13/^{\circ}C$(for $T_{wo}\;= \;5{\sim}11^{\circ}C$ range) at the specific heat extraction rate of 30W/m.

• 한국소음진동공학회논문집
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• 제23권7호
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• pp.624-630
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• 2013

In this study, a parametric study is performed to investigate the squeal noise of an automobile water pump. The squeal noise studied in this paper is generated by the self-excited torsional resonance of the rotating shaft, and this noise is related to the stick-slip phenomenon of the mechanical seal in the water pump. The mechanical seal friction has the characteristics of the negative velocity-gradient. The equations of motion of multiple-degree-of-freedom torsional vibration model is constructed by the Holzer's method and then the equation is transformed to an equivalent single-degree-of-freedom torsional resonance simulation model. A squeal noise criteria is determined by the simulation model to perform the parametric study. The design parameters(the mass moment of inertia of the pulley, the mass moment of inertia of the impeller, the length of the shafts, the radius of the shafts, spinning speed of the shafts, the position of the mechanical seal, radius of the mechanical seal, and normal load of the mechanical seal) are investigated to confirm the stability for the squeal noise.

• 한국지열·수열에너지학회논문집
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• 제15권3호
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• pp.14-20
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• 2019

In this study, the technologies and regulations for distributing standing column well(SCW) ground source heat pump systems to the residential cluster homes were investigated. They have only been installed in the public or commercial building having different load pattern and site structure compared with the residential cluster homes. Some of SCWs for the residential cluster homes should be installed under the basement due to a lack of site area. There are pressure differences between the SCWs installed under ground surface and basement. It is needed to develop the technology or devices to prevent overflow caused by pressure difference among the SCWs. In addition, heat balance algorithm between SCWs should be adopted to maximize the system efficiency. A heat pump having heating, cooling, hot water, heating-hot water, and cooling-hot water modes should be developed for adopting an individual air-conditioning system to the residential cluster homes.

• 한국대기환경학회지
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• 제16권6호
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• pp.675-684
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• 2000

A novel dry and wet deposition collector, which can overcome the several problems such as water evaporation cartridge cracks and high costs founded in the previous collector systems, has been constructed. ENVI-18 SPE adsorption cartridge has been used to measure atmospheric deposition of polycylic aromatic hydrocarbons (PAHs). A surrogate surface, consisted of water and methanol, was filled in the dry deposition funnel to simulate dry deposition onto water surface. A water supply system in order to compensat evaporation of the surrogate surface was used and it was consisted of a piston pump, a tubing pump, a overflow tube and a chamber system. A novel water vaporizing system to supply water onto the wet SPE cartridge system with a constant flow rate was developed. The novel water vaporizing system, consisted of a vacuum pump, a water supply reserviour and tube and a mini space heater, could prevent the PAHs adsorption cartridge cracks occurred in the previous collector and effectively adsorb PAHs. The novel dry and wet deposition collector showed a good adsorption, desorption, and recovery rates of PAHs. By reducing the number of pumps used and employing polypyopylene (PP) instead of teflon as a material of collection funnel, the total construction costs were much reduced as compared with the previous dry and wet deposition collectors.

• 한국산학기술학회논문지
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• 제14권5호
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• pp.2069-2074
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• 2013

내연기관 차량에 전자기식 클러치 워터펌프의 적용은 연비 향상 및 배기가스 저감을 꾀할 수 있다. 이러한 클러치 워터펌프는 엔진 냉각시스템의 유량 단속에 의하여 최적 운전 조건을 가능케 한다. 본 연구에서는 클러치 워터펌프를 이용한 냉각시스템을 제어함으로써 디젤 차량의 연비 및 배기가스 특성을 살펴보았다. 전자기식 클러치 워터펌프에 의한 저온 시동시 냉각수 흐름을 차단하여 아이들 조건에서 예열 시간을 기존 워터펌프 대비 49% 정도 단축시켰고, 주행 중에는 냉각수가 최적 고온상태를 유지하도록 제어하였다. 그리하여 NEDC 모드에서 연소 효율이 개선되어 최대 5% 정도의 연비 향상 효과를 나타내었다. 또한 NOx를 제외한 HC, CO 및 $CO_2$ 배기가스의 농도가 전반적으로 감소하였다.

• 한국정보통신학회논문지
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• 제7권5호
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• pp.1026-1031
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• 2003

자동 급수펌프는 압력스위치에 의해 운전 및 정지를 하게 된다. 따라서 수량 증감에 따른 펌프의 빈번한 운전 및 정지로 인해 지속적인 정격 및 정압 운전이 불가능하다. 또한 빈번한 작동으로 인해 지속적으로 일정한 압력을 얻을 수 없으며, 펌프의 소손과 에너지의 낭비가 심한 단점을 가지고 있다. 본 논문에서는 이러한 단점을 해결하고자 급수밸브, 유량센서, 제어장치로 구성되는 정압 급수장치를 설계 제작하였다. 급수밸브는 유출되는 물의 양과 관계없이 항상 일정한 양의 물을 유입하여 펌프의 부하를 줄이는 역할을 한다. 유량센서는 적외선 다이오드를 사용하여 유출되는 물의 양의 측정하며, 제어장치는 8 비트 마이크로프로세서를 이용하여 설계하였으며, 특별한 제어 알고리듬에 의해 펌프의 운전과 정지를 제어하게 하였다. 본 논문에서 개발한 장치는 토출 압력이 일정하게 유지되고 펌프의 작동 및 정지 동작이 부드럽게 이루어지며, 펌프의 지속적인 정압운전이 가능하므로 기존의 단점을 보완하는 장치로 사료된다.

• 대한기계학회논문집A
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• 제37권12호
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• pp.1483-1487
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• 2013

물 분사 펌프는 심해 유정의 시추작업 후 유정 내 높은 압력으로 인하여 원유를 1 차 생산하고 이후 유정 내 압력이 낮아져 유정 자체의 압력 만으로 생산이 어려울 때 고압의 해수를 유정에 주입해 회수율을 높이는 해양플랜트에서 사용되는 핵심 기자재이며, 여러 기업에서 개발 중이다. 본 논문은 회전체의 동특성 을 분석하여 베어링 강성에 따른 고유진동수 변화분석, 운전속도 변화에 따른 고유진동수의 변화와 위험속도 분석, 안정성 평가, 불평형 응답을 통하여 변위와 틈새 관계 분석 등의 수학적 해석을 통하여 개발 중의 제품의 신뢰성에 기여하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제31권8호
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• pp.1035-1041
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• 2007

An improvement of driving motor burning damages on a couplingless type warship fire pump is studied. The pump consists of an induction motor a pump-motor shaft and a volute type impeller. The burning damage had occured by changing the material of the pump-motor shaft from carbon steel(SM 45C) to stainless steel(STS 316) for improving anti-corrision properity in sea water. It is shown that a material change on the pump-motor shaft can reduce the efficiency of driving motor and may cause motor burning in the process of pump development stage. This kind of motor burning problem can be solved by increasing the efficiency of the motor and changing the geometry of the inner parts.

• 한국유체기계학회 논문집
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• 제18권4호
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• pp.36-42
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• 2015

This is a study about one of the most widely used hydro machinery all over the world - pump-turbine. The system has an impeller which pumps water to an upper reservoir during the night and the same impeller acts as a runner for turbine mode during the day for providing stable electrical power to the grid. The internal flow analysis is investigated in this study to help understand how the water passes through the passage of the vanes and blades, providing the designer with useful information on the behavior of recirculation flows which could reduce the efficiency of the pump-turbine. The 100 kW pump-turbine model has H = 32 m, $Q=0.336m^3/s$ and $N=1200min^{-1}$. For this study there are 7 blades, 19 stay vanes and 20 guide vanes. From this study, it was observed that this pump-turbine design showed very good internal flow characteristics with no flow separation and no recirculation flows in normal operation mode.