• Journal of Advanced Marine Engineering and Technology
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• 제31권5호
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• pp.592-598
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• 2007

The fuel charge is getting higher in navigation cost. Therefore, shipowners try to find the method for reducing oil consumption. ESS(Energy Saving System) is one of he method. ESS is the system consisted with two inverters, ESS control unit and monitoring system. Two inverters control two main sea water cooling pumps. In the ESS control Unit, the control algorithm finds optimized point to decrease a power consumption of main sea water cooling pumps. Monitoring system observes ESS not to work improperly. ESS is experimented in the laboratory with real condition and analyzed in every view. After experiment, the result of the experiment shows that the control algorithm works correctly and safely. ESS has a plan to be operated in the ship soon. In that case, additional devices are needed to connect ESS with cooling system of the vessel. So the development of addition device is needed and being studied.

• 한국태양에너지학회 논문집
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• 제34권2호
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• pp.53-59
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• 2014

Ice Rink is energy intensive building type. Concern of energy saving from buildings is one of very important issues nowadays. New and renewable energy sources for buildings are especially important when we concern about energy supply for buildings. Among new and renewable energy sources, use of seawater for heating and cooling is an emerging issue for energy conscious building design. The options of energy use from sea water heat sources are using deep sea water for direct cooling with heat exchange facilities, and using surface layer water with heat pump systems. In this study, energy consumptions for an Ice Rink building are analyzed according to the heat sources of air-conditioning systems; existing system and sea water heat source system, in a coastal city, Kangnung. The location of the city Kangnung is good for using both deep sea water which is constant temperature throughout the year less than $2^{\circ}C$, and surface layer water which should be accompanied with heat pump systems. The result shows that using sea water from 200m and 30m under sea lever can save annual energy consumption about 33% of original system and about 10% of that using seawater from 0m depth. Annual energy consumption is similar between the systems with seawater from 200m and 30m. Although the amount of energy saving in summer of the system with 200m depth is higher than that with 30m depth, the requirement of energy in winter of the system with 200m depth is bigger than that with 30m depth.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.56-61
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• 2009

Paradigm depending only on fossil fuel for building heat source is rapidly changing. Accelerating the change, as it has been known, is obligation for reducing green house gas coming from use of fossil fuel, i.e. reaction to United Nations Framework Convention on Climate Change. In addition, factors such as high oil price, unstable supply, weapon of petroleum and oil peak, by replacing fossil fuel, contributes to advance of environmental friendly renewable energy which can be continuously reusable. Therefore, current new energy policies, beyond enhancing effectiveness of heat using equipments, are to make best efforts for national competitiveness. Our country supports 11 areas for new renewable energy including sun light, solar heat and wind power. Among those areas, ocean thermal energy specifies tidal power generation using tide of sea, wave and temperature differences, wave power generation and thermal power generation. But heat use of heat source from sea water itself has been excluded as non-utilized energy. In the future, sea water heat source which has not been used so far will be required to be specified as new renewable energy. This research is to survey local heating system in Europe using sea water, central solar heating plants, seasonal thermal energy store and to analyze large scale central solar heating plants in German. Seasonal thermal energy store necessarily need to be equipped with large scale thermal energy store. Currently operating central solar heating system is a effective method which significantly enhances sharing rate of solar heat in a way that stores excessive heat generating in summer and then replenish insufficient heat for winter. Construction cost for this system is primarily dependent on large scale seasonal heat store and this high priced heat store merely plays its role once per year. Since our country is faced with 3 directional sea, active research and development for using sea water heat as cooling and heating heat source is required for seashore villages and building units. This research suggests how to utilize new energy in a way that stores cooling heat of sea water into seasonal thermal energy store when temperature of sea water is its lowest temperature in February based on West Sea and then uses it as cooling heat source when cooling is necessary. Since this method utilizes seasonal thermal energy store from existing central solar heating plant for heating and cooling purpose respectively twice per year maximizing energy efficiency by achieving 2 seasonal thermal energy store, active research and development is necessarily required for the future.

• Journal of Advanced Marine Engineering and Technology
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• 제39권4호
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• pp.468-472
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• 2015

최근 대두되는 선박배기가스 저감 등의 환경정책으로 인하여 에너지의 효율적 이용에 관심이 증가하고 있다. 본 논문에서는 함정의 에너지 효율 향상을 위하여 사용 부하에 따라 해수펌프를 제어하는 고효율 해수냉각시스템을 제안한다. 본 논문에서는 제안하는 시스템의 효과를 알아보기 위하여 추진 디젤기관의 냉각시스템을 모델링 하고 함정 운항특성을 고려한 시뮬레이션을 수행하였다. 시뮬레이션 결과 제안한 고효율 해수냉각시스템이 기존 해수냉각시스템에 비하여 약 53%의 에너지 절감효과가 있었다. 본 연구 결과는 향후 함정 추진 디젤기관의 해수냉각시스템의 성능 향상에 유용한 자료로 활용될 수 있다.

• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1157-1163
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• 2008

Fuel represents a significant portion of the operating costs of voyages of the vessel. Under this situation, dramatic increase in fuel price caused a problem that earnings of ship becomes decreased seriously. Pumps in a cooling system of the vessel are often operated inefficiently. The reasons will vary from process to process and application to application. Inefficiency of pumps is one of the reason for making the cost of operating the vessel increased. This paper suggests energy-effective cooling system that controls sea water pumps with inverters to reduce energy consumption in vessel by conducting simulation with LabVIEW. Results shows that electric energy consumption of pumps are significantly deceased. If this energy-effective cooling system is applied to other systems which need cooling, it could be useful in reducing electric energy wastage.

• Journal of Advanced Marine Engineering and Technology
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• 제22권5호
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• pp.680-686
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• 1998

In the adoption of a desalination system the most important factor is the cost of fresh water pro-duction. In general LNG is stored in a tank as a liquid state below $-162^{\circ}C$ When it is serviced however the LNG absorbs energy from a heat source and it is transformed to a high pressure gaseous state. During this process a huge amount of cold energy accumulated in cooling LNG is wasted. This wasted cold energycan be utilized to produce fresh water by using a sea water freez-ing desalination system. in order to develop a sea water freezing desalination system and to estab-lish its design technique qualitative and quantitative data regarding the freezing behavior of sea water is required in advance. The goals of this study are to reveal the freezing mechanisms of sea water in a cooled circular tube to measure the freezing rate and to investigate the freezing heat-transfer characteristics. The experimental results provide a general understanding of sea water freezing behavior in a cooled circular tube.

• 한국안전학회지
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• 제14권4호
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• pp.114-119
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• 1999

When NaOCl was generated and put into sea-water cooling machine in order to overcome the biological hindrances against sea-water cooling machine, it was converted into metallic ion, particularly Ca and Mg, as a hydrate in sea-water and is to stick to electrolyte as a side reaction. This phenomena make the distance between the electrolytes narrow to decrease the flow rate, which induces the local vortex flow which erodes the pole plate. Moreover, this increases the resistance of the electrolyte as well as voltage to decrease the electrolytic efficiency, which has curtailed a chlorine yield and caused a pole plate cut. We are able to overcome these problems by chemical cleaning and intend to extend the life-time of electrolyte and to increase output of the sea-water electrolysis facilities by studying optimal policy regarding chemical cleaning of electrolytic cell. Cleaning time of electrolytic facilities is determined when both increase in electrolytic efficiency and decrease in pole-plate voltage are 10%. At this time as operating current of electrolytic facilities is high, operating time is diminished. Whereas, parameter of end point determination according to cleaning is Mg ionic concentration in solution. When we use Cleaner as a 7wt% HCl, cleaning time is about 80min proper. We are able to maintain pole plate performance by protecting against pole plate cut by means of electrolytic by-product, improve operating rate of facilities, and cut down on maintenance expenditure after acidic cleaning.

• Journal of Advanced Marine Engineering and Technology
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• 제22권4호
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• pp.529-537
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• 1998

Currently as due to the rapid development of industry and increase in population we meet serious problems concerning the shortage and pollution of water. In the country many experts predict a shortage of water approaching 450 million tons by the year 2006. To cope with this serious problem it is necessary to construct desalination plants. In the adoption of a desalination system the most important factor is the cost of fresh water production,. In general LNG is stored in a tank as a liquid state below $-162^{\circ}C$. When it is serviced, however the LNG absorbs energy from a heat source and transforms to a high pressure gaseous state. During this process a huge amount of cold energy accumulated in cooling LNG is wasted. This wasted cold energy can be utilized to produce fresh water by using a sea water freezing desalination system. In order to develop a sea water freezing desalination system and to establish its design technique qualitative and quantitative data regarding the freezing behavior of sea water is required in advance, The goals of this study are to reveal the freezing behavior of sea water is required in advance. The goals of this study are to reveal the freezing mechanisms of sea water to measure the freezing rate and to investigate the freezing heat-transfer characteristics,. The experimental results will provide a general understanding of sea water freezing behavior in a rectangular vessel cooled from above.

• Journal of Advanced Marine Engineering and Technology
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• 제40권4호
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• pp.282-287
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• 2016

최근 조선사들은 선박이 운항되는 연안 환경의 개선과 보호를 위하여 $CO_2$를 절감할 수 있는 친환경 선박과 함께 선박 운항 중 소비하는 에너지의 절감을 위한 고효율화 선박 개발의 노력도 활발하게 수행하고 있다. 본 연구에서는 전기로 구동되는 선박의 증기압축식 냉동기 대신에 선박 엔진 자켓수의 폐열을 이용하여 냉방을 할 수 있는 흡수식 냉동기의 적용 가능성과 냉각시스템에 냉매를 적용하는 시스템의 성능을 분석하였다. 연구결과, 해수와 열교환하여 액화될 수 있는 냉매들 중 R236fa가 가장 적합한 냉매로 분석되었으며, 이를 적용한 흡수식 냉동기의 COP는 0.798로 육상의 냉각탑을 이용한 수랭식보다 15% 그리고 해수 열교환기식 수랭식보다 5% 향상되었다. 냉동능력 1RT를 얻기 위한 LiBr 흡수용액 순환량은 0.013 kg/s로 수랭식 보다 25% 이상 감소하며, 냉각 매체 순환량도 수랭식의 15.7%에 불과한 매우 효과적인 냉동기가 되었다. 해수온도가 $18^{\circ}C$ 이하로 낮으면 발생하게 되는 LiBr의 결정화는 재생기에서 배출되는 엔진 자켓수의 온도를 이용하여 해수 온도를 상승시킴으로써 방지할 수 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.699-705
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• 2013

This paper presents vibration testing, control, and finite element analysis of a piping system, which is subjected to the changes in fluid levels. Nuclear power plants typically employ a cooling system that uses sea water. These systems are subjected to dynamic characteristic changes caused by sea-level variations, which introduces failures of cooling system components. Therefore in this study, analytical and experimental studies were performed to understand the effect of sea-level changes on the dynamic characteristics of piping systems. It was shown that, as the sea-level increases, pipe's natural frequencies decreases in relation to its mode shape. A 1/14 scale model was also built to compare the results obtained by the analytical study. A good agreement between experiment and analytical studies were observed. Finally, an on-line resonant frequency identification system was proposed and developed, which utilizes piezoelectric transducers as sensors and actuators, in order to avoid catastrophic failure of piping systems.