• Journal of the Korean Wood Science and Technology
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• 제41권6호
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• pp.594-605
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• 2013

목질계 바이오매스는 폐기물 다음으로 가장 경제적이고 온실가스 감축 잠재력이 높은 것으로 알려진 신재생에너지원으로서 이를 이용해 개발된 바이오에너지 중에서 수송과 이용이 편리하고 발열량이 높은 목재 펠릿은 아직 가격이 다소 높지만 유럽과 일본에서는 이미 높은 보급률의 신재생에너지로 활용되고 있다. 기존 화석연료의 목재 펠릿 등 목질 바이오매스로의 연료전환을 통하여 온실가스 감축사업으로 활용하는 경우는 일본의 JCDM에서 활성화되어 있으나, 우리나라는 아직 그 기준 및 방법론 등이 정립되어 있지 않아 현재 LNG로 전환되는 사업이 활성화 되어있고 목질바이오매스 전환 사업은 등록되지 못하고 있는 실정이다. 본 연구를 통해 JCDM에 등록된 목질 바이오매스 연료전환 사업을 분석하고, 2012년 KVER에 등록된 중소기업의 LNG 연료전환 사업을 기본 데이터로 하여 시나리오로 가정한 목재 펠릿으로의 연료전환 사업과 JCDM 사업, KVER의 LNG 연료전환 사업과의 비교 분석을 통하여 펠릿 연료 전환시 투자비 대비 연간 온실가스 감축효과, 연료 단가 차익으로 인한 수익과 온실가스 감축 이득 등의 수익을 비교 분석함과 동시에 온실가스 감축효과와 경제성을 분석하였다.

• 한국포장학회지
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• 제25권2호
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• pp.31-35
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• 2019

Kimchi is a refreshing sour food which gives sour and carbonic acid taste of carbon dioxide produced during the fermentation process. So, carbon dioxide injection was tried to raise carbonic acid taste of kimchi stored in the airtight container. First, carbon dioxide injection times of a given gas supply system were determined experimentally to attain initial concentration of 80% for different solid/liquid ratios. Since carbon dioxide is dissolved in kimchi to decrease its concentration during storage, periodical carbon dioxide injection conditions were needed and determined to keep the $CO_2$ concentration above 70%. For the initial flushing to 80% $CO_2$ concentration in model system filled with water, the injection time ranged from 40 to 89 seconds for free volumes of 2-8 L. $CO_2$ injection conditions for the under-ripened storage at $10^{\circ}C$ consisted of longer time at more frequent cycles for watery kimchi than for Chinese cabbage kimchi. At $0^{\circ}C$ of subsequent ripened stage storage of watery kimchi, the periodical injection at 3 hour interval was required because of continuous dissolution of carbon dioxide. However, Chinese cabbage kimchi did not require subsequent $CO_2$ injection during the ripened state storage and needed only flushing to 80% $CO_2$ at time of the container opening and closing. These results can be used as basic information for the programmed control of $CO_2$ injection in the kimchi container system.

• 대한조선학회논문집
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• 제55권6호
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• pp.497-504
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• 2018

Platform Support Vessels operated in the Arctic Ocean support diverse operations of offshore plant in the sea, and the PSV is also needed to support works to exploit the oil and gas in the Arctic Ocean. Both of the ice breaking and the open sea performance have been considered together to secure the enhanced operational performance at the harsh environment in the Arctic Ocean and the open sea as well. In this study, One of the design requirements of a PSV is to guarantee continuous icebreaking performance with 3 knots at 1 m thickness of level ice, where the design draft is 7.5m and the engine power is 13 MW. Three hull forms were designed, and the ice resistance based on empirical formulas was estimated to select the initial hull form having an outstanding performance. The full scale performance of the designed hull forms was predicted by the ice model test conducted in the ice model basin of Korea Research Institute of Ships & Ocean Engineering(KRISO). The analysed results show that the selected hull form satisfies the above design requirement.

• 한국수소및신에너지학회논문집
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• 제29권6호
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• pp.654-660
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• 2018

The dependence on global fossil fuels has been gradually reducing all over the world. Some countries which recognized the important of environmental values were joining to carry out international GHG goals. Our country has also participated with high targets (37% reduction compared to BAU 2030 years). So we need to supply materials of lower GHG value such as a bio-diesel. Bio-alcohol is one of the similar bio-fuels that can be reducing GHG. A lot of countries had tried to commercialize through various R&D for bio-alcohol. In this study, we analyzed the fuel characteristics of bio-alcohol fuel produced by domestic technology. And we evaluated a possibility to use as vehicle fuel through mixing of bio-alcohol and gasoline. The mixed fuels were satisfied with 2.3 wt% of oxygen content that is standard of the petroleum and petroleum alternative fuel business Act. We tried to evaluate a emission characteristic of vehicle by mixed fuel. In accordance with the results we tried to find a correlation between fuel and emission.

• 한국항공우주학회지
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• 제47권8호
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• pp.599-606
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• 2019

펄스건 장치는 연소실 내, 다중 분사기 배열에 따른 연소 유동장으로의 횡단 압력파 전파/감쇠 메커니즘 규명을 목적으로 제작되었다. 제작된 펄스건은 성능시험을 통해 목표 연소압에서의 운용 가능 여부와 압력파 강도 제어 여부를 확인하였다. 기체질소를 사용하여 고압관에 가압을 하였으며 다이아프램에는 $100{\mu}m$ 두께의 OHP 필름을 사용하였다. 압력파의 속도와 강도를 확인하기 위해 압력 트랜스듀서를 이용하여 동압과 정압을 측정하였다. 제작된 펄스건은 공급압력에 따라 압력파의 강도 조절이 가능하며 횡방향성을 가지는 압력파를 생성할 수 있음을 성능시험을 통해 확인하였다.

• 한국수소및신에너지학회논문집
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• 제30권4호
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• pp.356-361
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• 2019

Since the government announced the roadmap to revitalize the hydrogen economy, we are constantly making the effort to expand the use of fuel cell electric vehicles (FCEV) and hydrogen charging stations. There is however a significant issue to build and operate the hydrogen charging station due to the lack of the profit model. Many researchers believe that the supply of FCEV will be increased in the near future and finally ensure the economy of hydrogen charging stations. This study shows that the sales changes of hydrogen gas and consumption patterns by the operation of the hydrogen charging station in Changwon City. The results will be used as the evidence to support for operating the hydrogen charging station by private businesses and the validity of additional establishment of hydrogen charging stations.

• 전기전자학회논문지
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• 제23권1호
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• pp.289-294
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• 2019

현재 국내 소규모 섬들은 주로 디젤발전기를 이용하여 전력을 공급하고 있다. 그러나 디젤발전기는 부하변동에 대한 속응성이 느리기 때문에 계통을 불안정하게 할 수 있고, 화석연료 사용에 의한 탄소가스 배출로 환경문제를 야기한다. 이러한 문제를 극복하기 위하여 본 논문에서는 주전원을 디젤발전기를 통하여 전력을 공급받고 있는 추자도에 태양광발전, 풍력발전, 에너지저장장치를 도입하여 최적의 마이크로그리드를 구축하는 방안을 제안한다. 이때 각 분산형 전원의 경제적 최적용량은 HOMER(Hybrid Optimization Model for Multiple Energy Resources) 프로그램을 이용하여 산정하였고, 이를 계통의 안정성을 분석할 수 있는 PSCAD/EMTDC(Power Systems Computer Aided Design/ Electromagnetic Transients including DC) 프로그램을 활용하여 제안한 마이크로그리드의 타당성을 입증한다.

• 한국건축친환경설비학회 논문집
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• 제12권6호
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• pp.543-556
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• 2018

Zero energy building was attended for energy consumption minimization by the energy saving technology about building heating and cooling energy consumption and the renewable energy production facility. So the government has supported the zero energy building supply for decreasing green gas emissions. The study about inventory of zero energy building has many proceeding. That inventory need the information of material and equipment. So information of material and equipment about zero energy building must be included for the zero energy building realization. Actually the database of zero energy building inventory construction through the inventory established studies has difficult because the database need many information. In this study, author proposed the test methods and performance reference for upload at inventory. It was constructed to material - module - package. Also the author analyzed the construction of the technical package for zero energy building. The author separated performance category to the energy performance for energy analysis and other performance for confirmed the durability, stability and etc. This performance category proposed the table. The test methods of material and equipment in the passive package and active package proposed to the international standard and korea standard basically korea standard. Also the performance reference was proposed to korea legal standard and various standard by this study results. And the authors proposed the table of performance value, test methods, performance reference. By result of this study, the test methods and performance reference will be used the basic data for inventory of zero energy building.

• 한국산학기술학회논문지
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• 제22권1호
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• pp.37-44
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• 2021

수소연료전지차(FCEV)는 전기를 자체 생산하는 연료전지를 동력원으로 하고 있으며 기존 기계식 레귤레이터의 출구압은 시스템 사양에 의해 제작 시점에서 고정되며 순간적인 수소 공급량에 의한 출구압 강하가 발생하는 경우 수소의 공급유량이 부정확해지는 문제가 있다. 본 연구에서는 기존에 존재하는 1단 기계식 감압 레귤레이터를 보완하기 위한 2단 감압 레귤레이터의 형상 설계 및 재질 선정을 수행하였다. 2단계 감압을 통한 맥동과 느린 응답을 보상하고 고압 편차 문제를 해결하기 위해 감압 유닛의 접촉면 형상을 가공성을 고려하여 설계하였다. 기밀성 측면에서 TPU의 변형량은 최대 15.82% 작은 변위량을 보였으며, 재질 선정에서는 2단 감압에 보편성을 확보하고 다양한 수소 연료 공급시스템에 적용 가능한 전자식 솔레노이드를 고려하여 자성체를 선정하고 적절한 도금 종류를 검증하기 위한 수소 취성 및 내식성 평가를 실시하였다. 시편의 표면 부식은 Cr 도금의 경우에서만 발생되지 않았으며, 인장 시험을 통해 부식과정간 연신율을 비교하였을 때, 2% 이내의 차이를 확인하였다.

• 한국해양공학회지
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• 제35권1호
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• pp.50-58
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• 2021

The demand for eco-friendly energy is expected to increase due to the recently strengthened environmental regulations. In particular, the flow inside the pipe used in a cargo handling system (CHS) or fuel gas supply system (FGSS) of hydrogen transport ships and hydrogen-powered ships exhibits a very complex pattern of multiphase-thermal flow, including the boiling phenomenon and high accuracy analysis is required concerning safety. In this study, a feasibility study applying the boiling model was conducted to analyze the multiphase-thermal flow in the pipe considering the phase change. Two types of boiling models were employed and compared to implement the subcooled boiling phenomenon in nucleate boiling numerically. One was the "Rohsenow boiling model", which is the most commonly used one among the VOF (Volume-of-Fluid) boiling models under the Eulerian-Eulerian framework. The other was the "wall boiling model", which is suitable for nucleate boiling among the Eulerian multiphase models. Moreover, a comparative study was conducted by combining the nucleate site density and bubble departure diameter model that could influence the accuracy of the wall boiling model. A comparison of the Rohsenow boiling and the wall boiling models showed that the wall boiling model relatively well represented the process of bubble formation and development, even though more computation time was consumed. Among the combination of models used in the wall boiling model, the simulation results were affected significantly by the bubble departure diameter model, which had a very close relationship with the grid size. The present results are expected to provide useful information for identifying the characteristics of various parameters of the boiling model used in CFD simulations of multiphase-thermalflow, including phase change and selecting the appropriate parameters.