• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.455-458
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• 2006

최근 들어 고체산화물 연료전지(SOFC) 기술이 급성장함에 따라 고온 수증기 전기분해(HTE) 기술이 물로부터 수소를 대량으로 제조할 수 있는 환경 친화적인 기술로 주목 받고 있다 고온 수증기 전기분해는 기존의 액상 전기분해보다 총 에너지 요구량이 작고 전기분해에 필요한 최소의 전기에너지가 온도가 증가할수록 감소하며 고온 수증기 전기분해에 요구되는 에너지의 일부를 전기에너지 대신 열의 형태로 공급이 가능하여 보다 높은 효율을 기대할 수 있다. 따라서 off peak시 기저부하전력을 이용하고, 공정의 열원으로 고온가스의 폐열, 천연가스의 부분산화 반응열 또는 고온 가스원자로의 폐열을 활용하면 SOFC 이용 고온 수증기 전기분해 공정은 수소경제사회에서 요구되는 수소를 대량으로 제조할 수 있는 경제적인 공정이 될 것이다.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.590-599
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• 2011

The electrification of the waste heat of fuel cell is necessary to enhance the efficiency of fuel cell system. For this purpose, the SOFC/ST(Solid oxide fuel cell/Steam turbine) hybrid system is suitable. The purpose of this work is to predict the performance of methane fueled SOFC/ST hybrid power system and to analyze the influence of operating temperature of stack, current density of stack, combustor outlet gas temperature, and boiler outlet gas temperature. According to the analysis, it is proved that making the best use of the waste heat of stack and minimizing the fuel consumption of combustor are essential for the high-efficiency of SOFC/ST hybrid system.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.172-174
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• 2007

본 연구는 가정용 연료전지 모니터링 사업을 통한 실증화 연구로써, 연료전지의 실용성에 대한 가치를 평가하고 실용화를 앞당기고자 하는데 목적을 두고 있다. 가정용 고분자 전해질 연료전지는 화학에너지를 전기에너지로 직접 변환함으로써 시스템 전체 효율이 80%이상의 고효율이고 환경 친화적이라는 점과, 연료전지 시스템의 운전 시 발생되는 폐열을 회수하여 급탕 및 난방용으로 활용함으로서 효율을 배가 시킬 수 있다는 장점 또 쉽게 구할 수 있는 LPG, LNG를 연료로 한다는 점을 특징으로 한다. 본 연구는 1kW 가정용 연료전지를 직접 구동하고 모니터링 함으로써 발생되는 문제점과 열병합 발전 시스템에 대한 연구를 진행하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.822-828
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• 2013

Since the operating temperature of Solid Oxide Fuel Cell (SOFC) is high, the heat management of the gases supplied to fuel cell system is important. In this paper, the temperature characteristic of the gases supplied to the anode and the cathode of the fuel cell is studied in case of utilizing the waste heat contained in the ship exhaust gas as a heat source to heat up the fuel, gas and water supplied to a 500kW SOFC system for a ship power. For the fuel cell system proposed in this paper, the temperature of gases supplied to the anode and the cathode was the highest temperature at 963K when the exhaust gas of the fuel cell was utilized as the heat source for gases supplied to fuel cell system instead of utilizing the ship exhaust gas. In addition, the engine power did not effect on the temperature of gases supplied to the fuel cell stack.

• Journal of Hydrogen and New Energy
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• v.34 no.6
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• pp.773-784
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• 2023

In this study, a comparative analysis between an electric heat pump cooling system and a hybrid desiccant cooling system is conducted. Desiccant cooling is a thermal driven system with potentially lower electric power consumption than electric heat pump. Hybrid desiccant cooling system simulation includes components such as a desiccant rotor, direct and indirect evaporative coolers, heat exchangers, fans, and a heat pump system. Using dynamic simulations by climate conditions, house cooling temperatures and power consumption for both systems are analyzed for 16 days period in the summer season under climate scenarios for the year 2100 prediction. The results reveal that the hybrid desiccant cooling system exhibits a 5-18% reduction in electric consumption compared to the heat pump system.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.307-312
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• 2023

In this study, a catalytic oxidation-heat recovery system was designed that can remove unreacted with a concentration of about 1% to 6% in the exhaust gas of hydrogen fuel cells and recover heat to ensure safety in the hydrogen economy. The safety system was devised by filling hydrogen oxidation catalysts at room temperature that can remove unreacted hydrogen without any energy source, and an exhaust-heat recovery device was integrated to efficiently recover the heat released from the oxidation reaction. Through CFD analysis, variations in pressure and fluid within the system were shown depending on the filling conditions of the hydrogen oxidation system. In addition, it was found that waste heat could be recovered by optimizing the temperature of the exhaust gas, flow rate, and pressure conditions within the heat recovery system and securing hot water above 40 ℃ by utilizing the exhaust gas oxidation heat source above 300 ℃. Through this study, it was possible to confirm the potential of utilizing hydrogen processes, which are applied in small to medium-sized systems such as hydrogen fuel cells, as a safety system by evaluating them at a pilot scale. Additionally, it could be a safety guideline for responding to unexpected hydrogen safety accidents through further pilot-scale studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.924-930
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• 2018

The objective of this study was to investigate heating performance characteristics of electric heat pump system in a fuel cell electric vehicle (FCEV). In order to analyze heating performance characteristics of electric heat pump system with plate-type heat exchanger using stack coolant to evaporate the refrigerant, R-134a, each component was installed and tested under various operating conditions, such as air inlet temperature of inner condenser and compressor speed. When the air inlet temperature of inner condenser was varied from $0.0^{\circ}C$ to $-20.0^{\circ}C$, heating capacity was not quite different due to similar temperature gap between inlet and outlet of inner condenser with electric-driven expansion valve (EEV). However, COP increased until certain EEV opening, especially under 45.0%, because of decreasing power consumption. According to the compressor speed variation from 2,000 to 4,000 RPM, heating capacity and COP were found to have opposite trend. In the future works, stack coolant conditions as the heat source for tested heat pump system were analyzed with respect to heating performance, such as heating capacity and COP.

• Journal of the Korean Institute of Gas
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• v.18 no.4
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• pp.13-20
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• 2014

In natural gas distribution system, gas pressure is regulated correspond to requirement using throttle valve which is releasing huge pressure energy as useless form. The waste pressure can be recovered by using turbo machinery devices such as a turbo expander. In this process, excessive temperature drop occurs due to Joule-Thompson effect during the expansion process. Installing natural gas boiler before or after the turbo expander prevents temperature drop. Fuel cell or gas engine hybrid system further improve the efficiency, but 1~2% of total transporting natural gas is used for operating the hybrid system. In this study, a heat pump system is proposed as a preheating device which can be operated without using transporting natural gas. Thermodynamic analysis on evaporating and condensing temperatures and refrigerants is conducted. Results show that R717 is proper refrigerant for the hybrid system with high COP and low turbine work within the defined operating conditions. In domestic usage in Korea, the heat pump system has more economic feasibility owing to natural gas being imported with a high price of LNG form.