• Journal of Hydrogen and New Energy
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• v.32 no.6
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• pp.431-441
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• 2021

UAE is first country in Middle East to approve UN Paris Climate Agreement. Ministry of Climate Change and Environment of UAE announced National Climate Change Plan for carbon reduction to replace 24% by clean energy. Dubai open its first hydrogen station in UAE and Middle East in 2017, and Abu Dhabi planed to open second hydrogen station in 2019 but not realized. Korean government announced hydrogen economy roadmap in 2019 and various hydrogen cooperation are realized between UAE, Korea, Germany, USA, and Japan. MOU between Ministry of State of UAE and Ministry of Land, Infrastructure and Transport of Korea in 2019 for the cooperation of hydrogen city. This study propose strategies for the 'Hydrogen Based Public Transport in UAE' by the support of Korea government considering various stakeholder.

• Journal of Cadastre & Land InformatiX
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• v.51 no.2
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• pp.83-106
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• 2021

Interests in clean fuels have been soaring because of environmental problems such as air pollution and global warming. Unlike fossil fuels, hydrogen obtains public attention as a eco-friendly energy source because it releases only water when burned. Various policy efforts have been made to establish a hydrogen based transportation network. The station that supplies hydrogen to hydrogen-powered trucks is essential for building the hydrogen based logistics system. Thus, determining the optimal location of refueling stations is an important topic in the network. Although previous studies have mostly applied optimization based methodologies, this paper adopts machine learning to review spatial attributes of candidate locations in selecting the optimal position of the refueling stations. Machine learning shows outstanding performance in various fields. However, it has not yet applied to an optimal location selection problem of hydrogen refueling stations. Therefore, several machine learning models are applied and compared in performance by setting variables relevant to the location of highway rest areas and random points on a highway. The results show that Random Forest model is superior in terms of F1-score. We believe that this work can be a starting point to utilize machine learning based methods as the preliminary review for the optimal sites of the stations before the optimization applies.

• Journal of Hydrogen and New Energy
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• v.27 no.3
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• pp.256-263
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• 2016

As the hydrogen era comes near future, hydrogen fuel cell vehicles are core of hydrogen economy. Until now, Korea has 17 hydrogen refueling stations but 9 hydrogen refueling stations have been retired already and 8 hydrogen refueling stations are still running. With a limited number of hydrogen refueling stations, it is very difficult to get scientific data for the economy of hydrogen refueling stations in Korea. Thus, based on NREL(National Renewable Energy Laboratory) study, we analyzed most recent data for the construction of hydrogen refueling stations in one specific site in Korea. The cost comparison data between Korea and USA shows 14% difference, saying higher costs of Korea. Korea looks 5 years delay compared to USA. This data will be an important tool for the investment from every industrial parties.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.36 no.9
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• pp.36-41
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• 2007

• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.1-8
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• 2011

In this research, the safety trends and technologies of HCNG, a mixture of hydrogen and natural gas, are analyzed. This is an attracting alternative fuels to meet the strengthened automotive exhaust gas emission standards. HCNG is very important opportunities and challenges in that it is available the existing CNG infrastructures, meets the strengthened emission standards, and the technical, social bridge of the coming era of hydrogen. It is essential for the commercialization of HCNG that hydrogen - compressed natural gas blended fuel for use in preparation of various safety considerations included accidents scenario, safety distance, hydrogen attack, ignition sources and fire detectors are examined. Risk assessments also are suggested as one of permission procedure for HCNG filling station.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.21-24
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• 2006

수소의 소규모 분산 생산 기술은 본격 적 인 수소 인프라가 도입되기 전에 연료전지 자동차의 수소 충전용이나 분산 발전형 연료전지의 수소 공급을 위해 필요하다. 생산 용량은 수소 기준으로 $20{\sim}100 Nm^3/hr$ 정도로 현재로선 천연가스의 수증기 개 질법이 가장 경제적인 공정으로 알려져 있다. 소규모 생산에 따른 열효율 저하를 줄이 기 위해 단위 공정들이 통합된 컴팩트 개질 시스템의 개발이 필요하다. 연료전지 자동차용 수소 인프라 조기 구축을 위하여 수소충전소 구축과 국산화 천연가스 수증기 개질기 개발을 병행하여 진행하였다. 수소 충전소 구축 부분은 충전소 부지 확보, 건물 건축, 각종 유틸리 티 설치의 토목 부분과 천연가스 개질형 수소 제조 유닛 설치, 수소 압축, 저장, 디스펜싱 시스템 설치를 포함하고 있으며 고압 설비에 대한 인허가 대응 및 안전대책 작업도 진행하였다. 구축된 수소충전소는 향후 연료전지 자동차 연계 실증 프로그램에 활용할 수 있다. 국산화 핵심 기술 개발을 위하여 열 및 시스템 통합 설계에 의 해 천연가스 수증기 개질기를 제작하고 내부 열교환 구조에 따른 개질기의 성능을 평가하였다. 개발된 개질기는 개질온도 $720^{\circ}C$, 수증기 대 카본 비 2.7의 운전조건에서 $23Nm^3/h$ 이상의 수소 생산이 가능하였으며 73% 이상의 개질 효율을 나타내었다. 개발된 천연가스 수증기 개질기는 향후 수소 정제용 PSA(Pressure Swing Adsorption) 시스템과 연계하여 수소충전소 국산화 엔지니어링 설계 패키지 개발의 핵심 기 술로 사용할 계획이다.시간 정도 운전한 후 시스템을 정지하였다 메탄 전환율과 일산화 탄소 농도, 열효율을 모니터링 하고 있으며, 현재까지 초기 성능을 그대로 유지하고 있다. 앞으로 일일시동-정지 운전 시험을 지속하면서 초기 시동 특성 및 부하 변동에 따른 응답 특성 개선, 그리고 연료전지와의 연계 운전을 실시할 예정이다 한다. 단위 전지 운전 온도 $130^{\circ}C$, 상대습도 37%의 운전 조건에서도 상당히 우수한 전지 성능을 보임에 따라 고온/저가습 조건에서 상용 Nafion 112 막보다 우수한 막 특성을 나타냄을 확인하였다.소/배후방사능비는 각각 $2.18{\pm}0.03,\;2.56{\pm}0.11,\;3.08{\pm}0.18,\;3.77{\pm}0.17,\;4.70{\pm}0.45$ 그리고 $5.59{\pm}0.40$이었고, $^{67}Ga$-citrate의 경우 2시간, 24시간, 48시간에 $3.06{\pm}0.84,\;4.12{\pm}0.54\;4.55{\pm}0.74 $이었다. 결론 : Transferrin에 $^{99m}Tc$을 이용한 방사성표지가 성공적으로 이루어졌고, $^{99m}Tc$-transferrin의 표지효율은 8시간까지 95% 이상의 안정된 방사성표지효율을 보였다. $^{99m}Tc$-transferrin을 이용한 감염영상을 성공적으로 얻을 수 있었으며, $^{67}Ga$-citrate 영상과 비교하여 더 빠른 시간 안에 우수한 영상을 얻을 수 있었다. 그러므로 $^{

• Journal of Hydrogen and New Energy
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• v.34 no.3
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• pp.246-255
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• 2023

Due to lack of hydrogen charging stations and hydrogen supply compared to the supply of hydrogen vehicles, social phenomena such as 2-hour queues and restrictions on charging capacity are occurring, which negatively affects the spread of hydrogen vehicles. In order to resolve these problems, it is essential to have a strategic operation of the hydrogen charging stations. To establish operational strategies, it is necessary to derive customer demand patterns and characteristics through the analysis of sales data. This study derived the demand patterns and characteristics of customers visiting hydrogen charging stations through data analysis from various perspectives, such as charging volume, charging speed, number of visits, and correlation with external factors, based on the hydrogen sales data of off-site hydrogen charging stations located in domestic residential areas.

• Journal of Hydrogen and New Energy
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• v.32 no.5
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• pp.356-364
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• 2021

During the hydrogen fueling process, hydrogen temperature inside the compressed tank were limited below 85℃ due to the allowable pressure of tank material. The chiller system to cool compressed hydrogen used R407C, greenhouse gas with a high global warming potential (GWP), as a refrigerant. To reduce greehouse gas emission, it should be replaced by refrigerant with a low GWP. This study proposes a chiller system for fueling hydrogen with R290, consisted in propane, by applying the C3 pre-cooled system use d in the LNG liquefaction process. The proposed system consisted of hydrogen compression and cooling sections and optimized the operating pressure through exergy analysis. It was also compared to the exergy efficiency with the existing system at the optimal operating pressure. The result showed that the optimal operating pressure is 700 kPa in 2-stage, 840 kPa/490 kPa in 3-stage, and the exergy efficiency increased by 17%.

• Journal of the Korean Institute of Gas
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• v.27 no.1
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• pp.38-47
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• 2023

In the hydrogen filling process, hydrogen flows by the pressure difference between the supply pressure at a filling station and a storage tank in the vehicle, and the flow rate depends on the pressure difference. Therefore, it is essential to consider the pressure drop of hydrogen occurring during the filling process, and the efficiency of the hydrogen filling process can be improved through its analysis. In this study, the pressure drop was analyzed for a hose, a nozzle/receptacle coupling, a pipe, and a valve in a filling line. The pressure drops through hose and pipe, the nozzle,receptacle coupling, and the valve were calculated by using a equation for a straight conduit, a flow nozzle formula, and a gas flow respectively. In addition, as a result of comprehensive analysis of the pressure drop effect occurring in each component, it was found that the factor that has the greatest influence on the pressure drop in the entire filling line is the pressure drop through the valve. This study can be used to develop a model of the hydrogen filling process by analyzing hydrogen flow including hydrogen filling in the future.

• Journal of Energy Engineering
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• v.26 no.4
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• pp.7-13
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• 2017

As environmental problems become a problem of survival, interest in eco-friendly energy is increasing to improve the environment. So, demand for eco-friendly fuels such as hydrogen, LPG and CNG is increasing. In particular, Korea, which relies on imports of most fuels, is investing in the development of hydrogen energy, which is favorable in terms of high production volume and energy independence. However, As demand grows every year, a variety of accidents occur in various ways, ranging from small leak incidents to massive fires and explosion, thus research needs to be done. So, in this study, compared and analyzed cases of hydrogen, LPG, CNG accidents occurring at domestic and overseas refueling stations. and various programs were used for assessing risk, estimated the flame length due to gas leakage and evaluated the dangerous distance.