• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.634-637
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• 2008

Ground source heat pumps are clean, energy-efficient and environment-friendly systems cooling and heating. Although the initial cost of ground source heat pump system is higher than that of air source heat pump, it is now widely accepted as an economical system since the installation cost can be returned within an short period of time due to its high efficiency. In the present study, performances of ground source compound hybrid heat pump system applied to a large community building are simulated. The system design and operation process appropriate for the surrounding circumstance guarantee the high benefit of the heat pump system applied to a large community building. If among several renewable energy sources, ground, river, sea, waste water source are chosen as available alternative energies are combined, COP of the system can be increased largely and hybrid heat pump system can reduced the fuel cost.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.80.1-80.1
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• 2011

This study was carried out in order to estimate the effect of heat pump performance by use of thermal tank with 3 seperation plates which were able to divide thermal tank into 3 chambers that have different temperatures levels. For testing the effect of developed thermal tank which was installed for supplying the heat to the paprika greenhouse in Jinju city. The volume of thermal storage tank was designed for $110m^3$ which was able to cover 30% of heating capacity. The temperature difference was 3 degree Celcius between high temperature and low temperature when only heating circulation was made from heat pump to thermal tank. but 5.5 degree Celcius difference was made when heating circulation of heat pump to thermal thank and hot water supplying circulation of thermal tank to greenhouse was done simultaneously. As a result of this study showed that COP of heat pump was increased by 15% or more than that of using normal thermal tank because heat pump was able to take 3 ~ 5 degree Celcius lower thermal thank water constantly.

• 설비공학논문집
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• 제26권6호
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• pp.257-262
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• 2014

This paper describes an experimental study for heating performance that can be used in R-134a automobile heat pump systems. The heat pump system is widely studied for heating system in zero-emission vehicles to attain both the small power consumption and the effective heating of the cabin. This paper presents the experimental results of the influence on heating capacity and coefficient of performance of heat pump system. Tests were performed with different sizes of internal and external heat exchangers, and refrigerant flow rate was also considered in two-way flow devices. In addition, the heat, air, and water sources with the heat pump system were examined. The experimental results with the heat pump system were used to analyze the impact on performances. The best combination of performance was A-inside heat exchanger, B-outside heat exchanger, and B-flow device, respectively. In addition, a water heat-source was found to give roughly 40% of better performance than an air heat-source heat pump system.

• 대한기계학회논문집
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• 제14권6호
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• pp.1629-1638
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• 1990

Using a 1/10 scale model pump, which is designed and manufactured to simulate two phase performance of reactor coolant pump of Y.G.N

• 한국자동차공학회논문집
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• 제22권5호
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• pp.20-28
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• 2014

The high velocity oxygen fuel spraying (HVOF) is a kind of surface modification process technology to form the sprayed coating layer after spraying the powder to molten or semi-molten state by the ultra-high speed at the high-temperature heat source and conflicting with a substrate. It is desirable to melt completely the thermal spray powder in order to produce the coating layer with an optimal adhesion, however, because a semi-molten powder in a spray process has the low efficiency and become a factor that degrades the mechanical property by the inducement of pore-forming within the coating layer. To improve the wear resistance, corrosion resistance and heat resistance, in this study, the plungers of high-speed and ultra-high pressure reciprocating hydraulic pumps for oil and water used in ironwork are produced with $420J_2$ and the coating layers of plungers are formed by the powders of WC-Co-Cr and WC-Cr-Ni including the high hardness WC. The surface of these plungers is modified by the super-mirror face grinding machine using variable air pressure developed in this laboratory, and then the characteristics of cross-sectional microstructure, and surface roughness and hardness values between no operation and 100 days-operation are examined and made a comparison. The fine tops and bottoms on surface roughness curve of oil-hydraulic pump plunger sprayed by WC-Cr-Ni are molded more and higher than those of water-hydraulic pump sprayed by WC-Co-Cr because the plunger diameter of oil-hydraulic pump is 0.4 times smaller than that of water-hydraulic pump and the pressure of oil-hydraulic pump exerted on the plunger is operated with the 70 bars higher than that of water-hydraulic pump. As a result, it is found that the values of centerline average surface roughness and maximum height for oil-hydraulic pump plunger are bigger than those of water-hydraulic pump plunger.

• 한국전산구조공학회논문집
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• 제31권2호
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• pp.79-85
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• 2018

기존의 한방향 펌프는 순환과 배수를 위해 각각의 모터를 사용하지만, 양방향 펌프는 하나의 모터로 모터의 회전 방향에 따라 배수와 순환이 모두 가능하므로 원가절감이 가능하다. 하지만 양방향 펌프는 배수와 순환 시 펌프 케이싱 내부에서 역류와 흡입이 발생하여 유입된 물이 각각 배출구와 순환구로 원활하게 유출되지 못하는 단점이 있다. 본 연구에서는 주효과 분석을 통해 배출과 순환 시 유출되는 유량과 토크에 주요한 영향을 미치는 인자를 설계변수로 선택하여 실험계획법, 근사모델, 그리고 최적설계를 통해 펌프 케이싱 형상을 최적화함으로써 역류와 흡입은 개선하고 펌프의 토크 대비 배출구와 순환구의 유량을 증가시키는 효과를 거두었다.

• 조명전기설비학회논문지
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• 제30권2호
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• pp.65-70
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• 2016

Power interruption is a phenomenon that no voltage is displayed over a short time or long time. Most devices will not operate normally when the supply voltage is low or does not exist. However, the device can also be operated with a different power which is ensured by a separate power generation. Recently, power interruption has been reduced gradually by the improvement of electricity quality, its duration also has been very short. Induction motors are widely used for the pumping in the water and sewage facilities and power plant applications. The pump is used as a machine for moving the fluid in the high place from a low location. So pump equipment always have a potential energy. If a momentary interruption occurs, the potential energy of the pump is reversed as that of water turbine and motor is operated as generator. This study is an analysis for the voltage variation, current, torque and power flow by the generating operation of the induction motor before and after the change of momentary interruption.

• 조명전기설비학회논문지
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• 제19권6호
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• pp.92-99
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• 2005

냉동 냉장창고용 냉수펌프 시스템을 태양광발전 시스템과 연계하여 펌프의 양정 및 유량의 변화에 따른 압력의 변화에도 불구하고 목표치 압력을 일정하게 제어할 수 있도록 하였다. BLDC 모터를 벡터제어 함으로써 각 운전속도의 영역에서 최대토크 운전 및 높은 신뢰성을 가능하도록 하여 냉동 냉장창고용 냉수 펌프 시스템의 에너지 절감 효과를 실현하였다.

• 한국환경과학회지
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• 제25권6호
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• pp.829-837
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• 2016

The mechanism of micro-bubble generation with a pump is not clarified yet, so the design of water treatment systems with a micro-bubble generating pump is based on trial and error methods. This study tried to explain clearly quantitative relationships of experimental micro-bubble concentration ($C_{air}$) of continuous operation tests with a micro-bubble generating pump and theoretical air solubility. Operation parameters for the tests were discharge pressure ($P_g$), water ($Q_{w0}$) and air ($q_0$) flow rates, orifice diameter ($D_o$), and retention time (t). The experimental micro-bubble concentrations ($C_{air}$) at 4.8 atm of discharge pressure ($P_g$) were in the range of 21.04 to 25.29 mL/L. When the retention time (t) by changing the pipe line length ($L_p$) increased from 1.22 to 6.77s, the experimental micro-bubble concentrations ($C_{air}$) increased from 25.86 to 30.78 mL air/L water linearly. The dissolved and dispersed micro-bubble concentrations ($C_{air}$) are approximately 4 times more than the theoretical air solubility.

• 설비공학논문집
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• 제20권4호
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• pp.280-286
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• 2008

In this study, characteristics simulation of heat pump system is investigated for heating and cooling using sewage water as a heat source. A simulation program for preestimate operation characteristics of heat pump system is developed. The performance of this system is resolved by several variables and the characteristics which is based on actual air and sewage temperature data. The simulation results agree well with the experimental values of COP. In the analysis of system characteristics, the COP is changed between $3\sim5$ in winter season for heating load, $4\sim6$ in summer season for cooling load. As the results of Life Cycle Cost analysis over a 15 year life cycle, the energy cost could be reduced by 250 million won if a heat pump system was used instead of a conventional boiler and an absorbtion refrigerator on the office building.