• Title/Summary/Keyword: solar fuel

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Study on the Thermal Storage Characteristics of Phase Change Materials for Greenhouse Heating (온실보온(溫室保溫)을 위한 상변화(相變化) 물질(物質)의 축열특성연구(蓄熱特性硏究))

  • Song, Hyun-Kap;Ryou, Young-Sun;Kim, Young-Bok
    • Solar Energy
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    • v.13 no.2_3
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    • pp.65-78
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    • 1993
  • An overdose of fossil fuel for greenhouse heating causes not only the high cost and low quality of agricultural products, but also the environmental pollution of farm village. To solve these problems it is desirable to maximize the solar energy utilization for the heating of greenhouse in winter season. In this study phase change materials were selected to store solar energy concentratively for heating the greenhouse and their characteristics of thermal energy storage were analyzed. The results were summarized as follows. The organic $C_{28}H_{58}$, and the inorganic $CH_3COONa{\cdot}3H_2O\;and\;Na_2SO_4{\cdot}10H_2O$ were selected as low temperature latent heat storage materials. The equation of critical radius was derived to define the generating mechanism of the maximum latent heat of phase change materials. The melting point of $C_{28}H_{58}$ was $62^{\circ}C$, and the latent heat was $50.0{\sim}52.0kcal/kg$. The specific heat of liquid and solid phase was $0.54{\sim}0.69kcal/kg^{\circ}C$ and $0.57{\sim}0.75kcal/kg^{\circ}C$ respectively. The melting point of $CH_3COONa{\cdot}3H_2O$ was $61{\sim}62^{\circ}C$, the latent heat was $64.9{\sim}65.8$ kcal/kg and the specific heat of liquid and solid phase was respectively $0.83kcal/kg^{\circ}C$ and $0.51{\sim}0.52kcal/kg^{\circ}C$. The melting point of $Na_2SO_4{\cdot}10H_2O$ was $30{\sim}30.9^{\circ}C$, the latent heat was 53.0 kcal/kg and the specific heat of liquid and solid phase was respectively $0.78{\sim}0.89kcal/kg^{\circ}C$ and $0.50{\sim}0.7kcal/kg^{\circ}C$ When the urea of 21.85% was added to control the melting point of $Na_2SO_4{\cdot}10H_2O$ and the phase change cycles were repeated from 0 to 600, the melting point was $16.7{\sim}16.0^{\circ}C$ and the latent heat was $36.0{\sim}28.0kcal/kg^{\circ}C$.

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A Study on a Hybrid Energy System to Reduce CO2 Emission In Mavuva Island, Fiji (마부바섬의 이산화탄소 감축을 위한 복합 에너지 시스템에 대한 연구)

  • Jung, Tae Yong;Hyun, Jung Hee;Lee, Seul;Huh, Minkyung
    • Journal of Environmental Impact Assessment
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    • v.26 no.4
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    • pp.217-226
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    • 2017
  • Although the effects of climate change are universal, Small Island Developing States (SIDS) are considered to be most vulnerable. SIDS heavily rely on imported oil and fossil fuels for electricity generation and transportation, which makes them economically vulnerable and exposed to fluctuating oil price. Among the reasons SIDS highly depend on diesel fuel is due to the dispersed population living in remote islands which means, providing electricity through on on-grid system is difficult. Fiji as one of the SIDS, has actively promoted renewable sourced energy through a national plan to mitigate the impacts of climate change. In order to determine how feasible implementing a renewable energy (RE) system will be in Fiji, this study chose a remote island called Mavuva Island to test application of a hybrid RE system using HOMER. A combination of energy storage system (ESS), solar photovoltaic (PV) and diesel generator turns out to be the most cost effective and optimal configuration, resulting in effective greenhouse gas reduction for the given region.

Improvement of Performance of Anti-reflective Coating Film Using Methyltrimethoxysilane (Methyltrimethoxysilane을 이용한 반사방지 코팅막의 성능 향상)

  • Keum, Young-Sub;Kim, Hyo-Sub;Park, Chu-Sik;Kim, Young-Ho
    • Applied Chemistry for Engineering
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    • v.26 no.4
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    • pp.400-405
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    • 2015
  • Traditional anti-reflective (AR) coating films prepared using tetraethylorthosilicate (TEOS) as a precursor absorbs water easily in addition to having a weak abrasion resistance. To improve the transmittance, hydrophobicity and abrasion resistance of AR coating film, various AR coating films were prepared using methyltrimethoxysilane (MTMS) as a precursor in addition to introducing a fluoroalkylsilane, acid catalyst, base catalyst and acid-base two step catalyst. The prepared AR coating films were then characterized by UV-Vis spectroscopy, contact angle analyzer, atomic force microscope (AFM), pencil scratch hardness test and cross-cut test. As a result, the transmittance of bare glass was 90.5%, while that of AR coating glass increased to 94.8% at curing temperature of $300^{\circ}C$. When the fluoroalkylsilane was added, the water contact angle of AR coating film increased from $96.3^{\circ}$ to $108^{\circ}$, indicating that the hydrophobicity of the film was greatly improved. The abrasion resistance of AR coating film was also improved by the acid catalyst, whereas the transmittance increased by the base catalyst. In the case of AR coating film prepared using an acid-base two step catalyzed reaction, both the transmittance and abrasion resistance of the film was synergistically enhanced as compared with those of AR coating films prepared without introduction of a catalyst.

Creating Electrochemical Sensors Utilizing Ion Transfer Reactions Across Micro-liquid/liquid Interfaces (마이크로-액체/액체 계면에서의 이온 이동 반응을 이용한 전기화학 센서 개발)

  • Kim, Hye Rim;Baek, Seung Hee;Jin, Hye
    • Applied Chemistry for Engineering
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    • v.24 no.5
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    • pp.443-455
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    • 2013
  • Electrochemical studies on charge transfer reactions across the interface between two immiscible electrolyte solutions (ITIES) have greatly attracted researcher's attentions due to their wide applicability in research fields such as ion sensing and biosensing, modeling of biomembranes, pharmacokinetics, phase-transfer catalysis, fuel generation and solar energy conversion. In particular, there have been extensive efforts made on developing sensing platforms for ionic species and biomolecules via gelifying one of the liquid phases to improve mechanical stability in addition to creating microscale interfaces to reduce ohmic loss. In this review, we will mainly discuss on the basic principles, applications and future aspects of various sensing platforms utilizing ion transfer reactions across the ITIES. The ITIES is classified into four types : (i) a conventional liquid/liquid interface, (ii) a micropipette supported liquid/liquid interface, (iii) a single microhole or an array of microholes supported liquid/ liquid interface on a thin polymer film, and (iv) a microhole array liquid/liquid interface on a silicon membrane. Research efforts on developing ion selective sensors for water pollutants as well as biomolecule sensors will be highlighted based on the use of direct and assisted ion transfer reactions across these different ITIES configurations.

A Development of Green Transportation Design for Special Identity of Jecheon Area - centered on Exterior Design for Development of Design Business - (제천지역의 특성화를 위한 친환경운송수단 디자인개발 - 디자인비즈니스 개발을 위한 익스테리어 디자인을 중심으로 -)

  • Mun Keum-Hi
    • Archives of design research
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    • v.19 no.4 s.66
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    • pp.175-186
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    • 2006
  • In the 21C, each nation controls exhaust fumes from automobiles and makes an effort to develop alternative energy because of serious environmental problem. Jechon area has many historical and cultural archeological sites. And Jechon city sponsors various cultural events. But the way of transportation which is connected with Jecheon and around sightseeing places is general and not ready yet. Therefore, if a special means of vehicle is developed, it could play an another role of sightseeing resources. Special identity of Jecheon area for establishment of green vehicle traffic system which gives Jecheon area specific character was investigated for theoretical background. Traffic system was studied for establishment of direction through existent successful case study. Moreover content, method, structure and advantage & shortcoming etc. of vehicle that use green energy resource such as solar car, fuel cell car, hybrid car, natural gas car etc. were examined. The suitable means of vehicle for Jechon area was proposed to three directions with research and investigation. After comparison and investigation by inquiry of each section's experts, the most suitable traffic system of which energy resource of car, form of vehicles, the complement, dimension of vehicles etc. were decided. Design proposal should be drawn according to process of automobile design in decided direction. Special Exterior design of vehicle that use green energy resource connecting Jecheon and around area should be suggested in Jecheon City Hall and Chungchong-bukdo provincial office for vivify image of cleanliness area.

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An Analysis of Energy technology utilization through Patent Analysis at domestic and abroad (특허분석을 통한 국내외 에너지기술 활용도 분석 - 태양전지, 연료전지, CCS를 중심으로 -)

  • Koo, Kikwan;Lee, Deokki;Hong, Seongjun;Hong, Jongcheol;Park, Soouk
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.151-151
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    • 2011
  • 오늘날 에너지문제는 인류가 직면한 가장 중요한 당면과제 중 하나이다. 석유, 석탄과 같은 화석에너지는 점점 고갈되어 가고 있으며, 이산화탄소 배출로 인한 기후변화도 해결이 시급한 문제이다. 이러한 문제들을 해결하기 위한 방안으로 신재생에너지의 중요성이 부각되고 있다. 특히 신재생에너지 기술 중 태양전지는 미국, 일본, 유럽, 중국 등 많은 국가에서 기술개발 및 보급에 앞장서고 있으며, 시장선점을 위한 기술개발 경쟁이 치열하다. 또한 연료전지의 경우 전기와 열을 동시에 생산 가능하며, 다른 에너지 변환기보다 훨씬 높은 효율을 가지고 있어 신에너지원으로서 주목받고 있다. 이와 함께 기후변화에 실질적인 해결책으로 세계는 CCS에 기대하고 있으며, 기술개발 및 실증을 위한 국제공동연구도 활발하게 진행 중이다. 본 논문에서는 이러한 중요성을 인식하여 태양전지, 연료전지 그리고 CCS에 대하여 국내외 에너지기술 활용도를 분석하였다. 활용도 분석을 위하여 특허등록건수, 특허의 피인용 정보와 이를 활용한 CPP지수를 산출하였다. 오늘날 특허는 국가나 기업 등 특정 주체에 대한 기술력 또는 혁신성을 측정하거나, 기술개발 동향을 파악하기 위한 중요한 정보로 사용된다. 특히 CPP지수(특허당 피인용지수)는 분석대상(국가, 기업 등)의 특허가 이후의 기술혁신 활동에 어느 정도의 활용되어 영향을 미쳤는가를 보여주는 지표로써, 특정 국가나 기업의 기술혁신 활동의 수준 및 혁신성과의 가치를 살펴 볼 수 있다. 이를 통하여 국내의 에너지기술 경쟁력을 살펴보고 시사점을 도출하였다. 우선 특허데이터 수집을 위하여 톰슨 이노베이션을 활용하여 2001년부터 2010년까지 미국, 일본, 유럽, 한국에 등록된 특허를 검색하였으며, 특허등록번호를 중심으로 중복데이터를 제거하였다. 또한 특허명칭, 요약정보를 통하여 노이즈를 제거하였다. 노이즈가 제거된 특허를 활용하여 기술별, 국가별 기술개발 동향을 살펴보았으며, CPP지수를 통하여 기술별, 국가별 활용도를 분석하였다. 분석 결과, 태양전지의 경우 대부분의 국가에서 특허건수가 매년 증가함에 따라, 지속적으로 기술경쟁이 심화되고 있는 것으로 분석되었다. 또한 한국의 CPP지수는 미국, 일본 등 주요 경쟁국가에 비해 상당히 낮게 나타나 기술 활용 수준이 낮은 것으로 분석되었다. 따라서 핵심기술 개발과 같은 에너지기술의 질적수준을 높이기 위한 대책마련이 필요한 실정이다. 본 논문의 결과를 통하여 특허를 위한 기술개발이 아닌 보다 활용성이 높은 기술개발이 이루어지기를 바라며, 나아가 국가에너지기술 경쟁력을 높이는데 기여할 것으로 기대한다.

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Design and Analysis of Korean Lunar Orbiter Mission using Direct Transfer Trajectory (직접 전이궤적을 이용한 한국형 달 궤도선 임무설계 및 분석)

  • Choi, Su-Jin;Song, Young-Joo;Bae, Jonghee;Kim, Eunhyeuk;Ju, Gwanghyeok
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.12
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    • pp.950-958
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    • 2013
  • The Lunar orbiter is expected to be inserted into a ~300km low Earth orbit using Korea Space Launch Vehicle-II(KSLV-II). After the states are successfully determined with obtained tracking data, the Trans Lunar Injection(TLI) burn has to be done at appropriate epoch to send the lunar orbiter to the Moon. In this study, we describe in detail the mission scenario of the Korean lunar orbiter from the launch at NARO Space Center to lunar orbit insertion(LOI) stage following direct transfer trajectory. We investigate the launch window including launch azimuth, delta-V profile according to TLI and LOI burn positions. We also depict the visibility conditions of ground stations and solar eclipse duration to understand the characteristics of the direct transfer trajectory. This paper can be also helpful not only for overall understanding of ${\Delta}V$ trend by changing TOF and coasting time but for selecting launch epoch and control parameters to decrease fuel consumption.

Influence of Processing on Morphology, Electrical Conductivity and Flexural Properties of Exfoliated Graphite Nanoplatelets-Polyamide Nanocomposites

  • Liu, Wanjun;Do, In-Hwan;Fukushima, Hiroyuki;Drzal, Lawrence T.
    • Carbon letters
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    • v.11 no.4
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    • pp.279-284
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    • 2010
  • Graphene is one of the most promising materials for many applications. It can be used in a variety of applications not only as a reinforcement material for polymer to obtain a combination of desirable mechanical, electrical, thermal, and barrier properties in the resulting nanocomposite but also as a component in energy storage, fuel cells, solar cells, sensors, and batteries. Recent research at Michigan State University has shown that it is possible to exfoliate natural graphite into graphite nanoplatelets composed entirely of stacks of graphene. The size of the platelets can be controlled from less than 10 nm in thickness and diameters of any size from sub-micron to 15 microns or greater. In this study we have investigated the influence of melt compounding processing on the physical properties of a polyamide 6 (PA6) nanocomposite reinforced with exfoliated graphite nanoplatelets (xGnP). The morphology, electrical conductivity, and mechanical properties of xGnP-PA6 nanocomposite were characterized with electrical microscopy, X-ray diffraction, AC impedance, and mechanical properties. It was found that counter rotation (CNR) twins crew processed xGnP/PA6 nanocomposite had similar mechanical properties with co-rotation (CoR) twin screw processed or with CoR conducted with a screw design modified for nanoparticles (MCoR). Microscopy showed that the CNR processed nanocomposite had better xGnP dispersion than the (CoR) twin screw processed and modified screw (MCoR) processed ones. It was also found that the CNR processed nanocomposite at a given xGnP content showed the lowest graphite X-ray diffraction peak at $26.5^{\circ}$ indicating better xGnP dispersion in the nanocomposite. In addition, it was also found that the electrical conductivity of the CNR processed 12 wt.% xGnP-PA6 nanocomposite is more than ten times higher than the CoR and MCoR processed ones. These results indicate that better dispersion of an xGnP-PA6 nanocomposite is attainable in CNR twins crew processing than conventional CoR processing.

자기조립 특성을 이용한 공정 및 응용소자 개발

  • Lee, Jae-Gap
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2012.05a
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    • pp.52-52
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    • 2012
  • 최근 선진국을 중심으로 제조기술의 산업혁명이라고 불릴 정도로 큰 파급효과가 기대되는 자기조립기반의 산업공정기술을 확보하기 위한 많은 노력과 연구들이 활발하게 진행되고 있다. 자기조립(Self-Assembly) 현상은 자연에서 일어나는 자발적인 힘으로 원자 또는 분자 단위까지 구조물을 제어하고 bottom-up 방식(상향식: 원자/분자 스케일의 나노구조를 배열/조립하여 원하는 형태의 패턴을 만들어 내는 방식)으로 원하는 구조물을 설계/제작할 수 있는 능력을 가지고 있다. 기초적인 과학으로부터 출발한 자기조립기술은 최근 자기조립 응용개발에서 많은 성과를 이루어내면서 산업화 가능성을 크게 하고, 과학계와 산업계의 많은 관심을 불러일으키고 있다. 반도체 산업기술을 예측하는 ITRS 로드맵(2005년)에 의하면 directed self-assembly 방법이 새로운 미래 패터닝 기술로 개발되어 2016년경에 사용되고, 자기조립소재로 제작된 다양한 응용소자들은 새로운 미래소자로 개발될 것으로 예상하고 있다. 이에 맞추어 국내 기업들도 diblock copolymer를 이용한 나노패터닝 기술 확보를 위한 연구를 진행하고 있다. 또한 IBM은 자기조립기술을 반도체공정에 실험적으로 적용하여 자기조립기술이 생산 공정에 부분적으로 적용될 가능성이 크다는 것을 보여주었다. 산업계와 함께 학계의 연구센터에서는 산업화를 위한 자기조립 집적화 공정(Integrated process) 개발을 이루기 위하여 체계적으로 연구를 실시하고 있다. 미국의 Northeastern 대학의 CHN(Center for high-rate Nanomanufacturing) 연구센터는 자기조립 집적화에 용이한 새로운 개념의 소자를 제안하고 이를 집적화하기 위한 다양한 공정을 개발하고 있으며, Wisconsin 대학의 NSEC(Nanosacle Science and Engineering Center) 연구센터는 diblock copolymer를 이용한 나노패터닝 기술 개발에서 획기적인 결과를 도출하여 산업계에 적용될 가능성을 높이고 있다. 이와 같은 결과들로부터 앞으로의 자기조립기술에 대한 연구는 3차원 구조물을 제작할 수 있는 집적화 공정에 집중될 것이고, 이를 위하여 새로운 개념의 단순한 구조의 응용소자개발도 함께 추진될 것으로 판단된다. 또한 실용 가능성이 큰 집적화 공정으로 개발하기 위하여 기존의 top-down 방식을 접목한 bottom-up 방식의 자기조립 집적화 공정이 개발될 것으로 예상하고 있다. 이와 함께 자기조립공정은 반복되는 구조를 쉽게 제작할 수 있는 장점을 가지고 있어 다양한 응용소자 [태양전지(solar cell), 연료전지(fuel cell), 유연성 있는 전자기기(flexible electronics), 화면표시 장치(display device)] 제작에 쉽게 이용되어 새로운 산업을 창출할 수 있는 가능성을 보이고 있다. 본 자기조립 연구 센터에서는 이와 같은 자기조립 특성을 제조공정에 적용하여 혁신적인 제조공정기술을 확보하고자 연구를 진행하고 있다. 그러므로 본 발표에서 이와 같은 연구 흐름과 함께 본 센터에서 진행하고 있는 자기조립 제조방법을 소개하고자 한다. 이와 함께 자기조립방법을 이용하여 제작된 다양한 응용소자 개발 결과를 발표하고, 이를 top-down 방식과 접목하여 집적화공정으로 개발하는 전략을 함께 소개하고자 한다.

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A Study on the Application of Domestic ferry to a Battery Propulsion Ship connected with Photovoltaic System (태양광 발전시스템이 연계된 배터리 전기추진선박의 국내 유람선 적용에 관한 연구)

  • Hwang, Jun-Young;Jeon, Cheol-Hwan;Jeon, Hyeon-Min;Kim, Jong-Su
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.7
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    • pp.945-952
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    • 2019
  • The International Maritime Organization (IMO) adopted the International Convention on the Control of Ships' Air Pollutants and Discharge as it became interested in environmental issues such as global warming and air pollution. In addition, a special bill on the improvement of air quality, including in port areas, has recently been enacted in Korea to reduce the amount of fine dust generated. As part of such fine dust reduction measures, feasibility studies have been underway on converting diesel engines into battery electric propulsion systems that do not cause fine dust and emissions. Since the battery electric propulsion system can easily utilize renewable energy sources, and does not generate exhaust gas due to combustion of fuel, small coastal ferries with battery electric propulsion systems that use renewable energy have been operating in Europe and the U.S. for several years. However, they have not been introduced in Korea. Therefore, in this study, we selected small coastal ferries in Korea as target ferries, and performed simulations to study the applicability of electric propulsion with batteries linked to solar power systems. Based on the results, we want to confirm the applicability of battery electric propulsion.