• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2018년도 추계학술발표대회
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• pp.350-352
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• 2018

In this paper, we propose a smart indoor garden aquaculture system using PIC. In the proposed smart indoor garden aquaculture system, the aquaphonics system circulates the nutrient solution of the aquarium, the filtrate tank, and the flowerpot. The automated control system that controls the state of the nutrient solution through the various sensors and controls the pump and valve is designed. As a result of the verification of the smart indoor garden aquaculture system proposed in this paper, it was confirmed that the environment suitable for the survival of fish and plants was maintained by monitoring water temperature, DO, pH measured in real time. The water level in aquarium and flower pot was controlled through automatic operation of the Electric vale and pump.

• 상하수도학회지
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• 제21권5호
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• pp.609-619
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• 2007

The objective of this paper is to evaluate the feasibility of conjunctive Operation between Multi-regional water supply networks from multiple source as a effective way to meet two conditions: to minimize the electric cost for providing water demanded and meet the water flow rate for satisfying customers. EPAnet Model is used to calculate a hydraulic water distribution condition based on an integrated operation of water supply systems located in short distance. The modeling was conducted on several simulation cases including the individual operation by existing inter-regional water supply networks within short distance, the conjunctive operation of more than two existing networks with valve fully closed and full open constraint. As a study distribution system, water supplying systems of the Geojae-city in the Geongsang Namdo Province was selected and investigated. It was found that a well-allocated water supply scheme based on a conjunctive operation promises to save the electric cost and satisfy all operational goals such as stability and revenues during the period. The result such as unit district costs, pareto optimum pump combination sets will be applied to the optimization for a conjunctive operation of existing inter-regional water supply networks within short distance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1603-1604
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• 2007

The load of power plants changes every from time to time according to which steam flow of boiler changes. the feed water control is very important for the power plant to be operated in its stability conditions. In case of circulation type boiler, the instability of feed water control leads to instability of drum level control. The higher level of drum water can induce bad quality steam to go into turbine which means the possibility of damage. The lower level of drum water can induce the tubes of boiler water wall to be overheated. In case of once through type boiler, the instability of feed water control leads to bad cooling of superheaters. The less the feed water flow is, the more heated the superheater is. It is necessary for the turbine driving feed water pump to be controlled for the optimal feed water flow in the large capacity power plant. The speed of turbine is controled for the feed water flow. By the way, the optimal control of steam valve is necessary for the speed control of turbine. Therefore, the various kinds of the steam valve structures are introduced in this paper

• 상하수도학회지
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• 제22권4호
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• pp.437-444
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• 2008

Many other countries have investigated the new backwash water treatment process to save the existing water resource. There are various methods for reusing backwash water, but the membrane system has received the most interest for its efficiency. The objective of this study was to certify the application of membrane filtration system for the backwash water treatment. The experiment equipment was composed of Lab scale tubular membrane filtration system. Generally, cross-flow operation mode is used in the tubular membrane system but cross-flow operation mode demands high electric cost mainly for the pump energy. So to cut off electric cost, dead-end operation mode was used in this experiment. Filtration and bleed operation cycle was used in this membrane system. Backwash water was concentrated during the filtration process and when backwash water reached our target suspended solid concentration, it was discharged from this system. For efficient operation of filtration and bleed, mathematical matrix was drawn up and with this matrix we could simulate various sets of filtration and bleed time.

• 자원환경지질
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• 제49권3호
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• pp.243-248
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• 2016

본 연구는 수격펌프를 이용하여 용수 공급의 가능성과 효율성을 평가하기 위하여 수행되었다. 연구지역은 경상북도 상주시 화남면 임곡리로 과거 석탄개발에 사용된 갱도로부터 지속적으로 지하수 유출이 발생하고 있다. 유출되는 지하수는 일평균 약 $260m^3/day$의 수량을 가지는 것으로 파악되었다. 수격펌프는 수격현상을 이용하여 전력없이 공급원으로부터 고도차(압력)에 의해 물의 일부를 높은 곳으로 이송시키는 펌프이다. 수격펌프의 효율성을 파악하기 위해 수격펌프와의 고도차에 따라 3지점(${\Delta}h=19m$ (1지점), 30 m (2지점), 40 m (3지점))에서 유량을 측정하였다. 1지점에서는 약 $8.6{\sim}10.8m^3/day$, 2지점은 약 $3.98{\sim}4.39m^3/day$ 그리고 3지점에서는 약 $2.35{\sim}2.59m^3/day$의 물을 운반할 수 있는 것으로 파악되었다. 이번 연구를 통해 수격펌프가 산간지역 등에서 전력없이 물공급 시스템에 활용할 수 있을 것으로 파악되었다.

• KIEAE Journal
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• 제16권6호
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• pp.109-114
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• 2016

Purpose: The underground air is the warm air discharged from the porous volcano bedrock 30-50m underground in Jeju, including excessive humidity. The temperature of the underground air is $15-20^{\circ}C$ throughout the year. In Jeju, the underground air was used for heating greenhouses by supplying into greenhouses directly. This heating method by supplying the underground air into greenhouses directly had several problems. The study was conducted to develop the heat pump system using underground air as heat source for resolving excessive humidity problem of the underground air, adopting the underground air as a farm supporting project by Ministry of Agriculture, Food and Rural Affairs(MAFRA) and saving heating cost for agricultural facilities. Method: 35kW scale(10 RT) heat pump system using underground air installed in a greenhouse of area $330m^2$ in Jeju-Special Self-Governing Province Agricultural Research & Extension Services, Seogwipo-si, Jeju. The inlet and outlet water temperature of the condenser, the evaporator and the thermal storage tank and the underground air temperature and the air temperature in the greenhouse were measured by T type thermocouples. The data were collected and saved in a data logger(MV200, Yokogawa, Japan). Flow rates of water flowing in the condenser, the evaporator and the thermal storage tank were measured by an ultrasonic flow meter(PT868, Panametrics, Norway). The total electric power that consumed by the system was measured by a wattmeter(CW240, Yokogawa, Japan). Heating COP, rejection heat of condenser, extraction heat of evaporator and heating cost were analyzed. Result: The underground air in Jeju was adopted as a farm supporting project by Ministry of Agriculture, Food and Rural Affairs(MAFRA) in 2010. From 2011, the heat pump systems using underground air as a heat source were installed in 12 farms(16.3ha) in Jeju.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2272-2274
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• 2004

원자력 발전소용 급수펌프 터빈의 속도제어 시스템을 개조하는데 중요한 요소인 밸브제어 계통의 구성방법 및 각종 제어 상수를 시험을 통해 미리 파악하여 현장 적용시 발생될 문제점을 해결하고자 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1628-1629
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• 2007

1990년대에 이 전 건설된 발전소 및 기타 플랜트 자동제어시스템으로 거의 아날로그 연산방식 시스템이 적용되었다. 이제 장기간 사용으로 인한 수명감소와 고장률이 증가하는 추세에 있으므로, 기존 아날로그 제어시스템을 디지털 제어시스템으로 개조하는 사업이 추진되고 있다. 아날로그 제어시스템에 설정되어 있는 주요 파라미터들은 플랜트의 운전특성을 장기간 반영하여 이루어진 것이므로, 개조에 사용될 새로운 디지털제어시스템의 초기 파라미터 설정에 그대로 적용하면 개조후 시운전이 원활하고 튜닝 기간을 단축할 수 있다. 본 논문에서는 현재 진행하고 있는 급수펌프 구동터빈 제어시스템 개조 프로젝트에서 제어 파라미터를 구하는 과정 및 디지털 시스템에 구현할 내용들을 제시하였다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
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• pp.159-164
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• 2000

In this paper a new type refrigerant liquid subcooling system which adopts ice storage system is proposed. And the cycle characteristicso of a new system was investigated. Since this system subcools a refrigerant in the daytime using the ice storaged by electric power in the night it is high efficiency heat pump system which have the merit of ice storage system and possible to improve the performance of the heat pump. The running to storage the ie was carried out for 10 hours in the night and th evaporating temperature was set on $-5^{\circ}C.$ Subcooling operation stayed as 430^{\circ}C$ subcooling degree and perfomed till the water in the IST(Ice storage tank) was reached $12^{\circ}C$. The experimental result showed that a new system was superior to the existing refrigeration system generally. The total cooling capacity of a new system was about 11% higher than that of the existing refrigeration system. And the COP of a new system was improved by 22% compared to the existing refrigeration system.

• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.97-102
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• 2013

Frequency tuning characteristics of a THz-wave by varying phase-matching angle and pump wavelength in a noncollinear phase-matching THz-wave parametric oscillator (TPO) are analyzed. A novel scheme to realize the tuning of a THz-wave by moving the cavity mirror forwards and backwards is proposed in a noncollinear phase-matching TPO. The parametric gain coefficients of the THz-wave in a $LiNbO_3$ crystal are explored under different working temperatures. The relationship between the poling period of periodically poled $LiNbO_3$ (PPLN) and the THz-wave frequency under the condition of a quasi-phase-matching configuration is deduced. Such analyses have an impact on the experiments of the TPO.