• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.4
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• pp.341-347
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• 2010

In this study, the efficiency of a solid-oxide fuel cell (SOFC) system with a steam reformer or prereformer was analyzed under various conditions. The main components of the system are the reformer, SOFC, and water boiling heat recovery system. Endothermic and exothermic reactions occur in the reformer and SOFC, respectively. Hence, the thermal management of the SOFC system greatly influences the SOFC system efficiency. First, the efficiencies of SOFC systems with a steam reformer and a prereformer are compared. The system with the prereformer was more efficient than the one with steam reformer due to less heat loss. Second, the system efficiencies under various prereformer operating conditions were analyzed. The system efficiency was a function of the heat requirement of the system. The efficiency increased with an increase in the operating temperature of the prereformer, and the maximum system efficiency was observed at $450^{\circ}C$ for a S/C of 2.0.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.552-552
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• 2005

• Journal of the Korean Ceramic Society
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• v.45 no.12
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• pp.772-776
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• 2008

The Korea Electric Power Research Institute (KEPRI) has been developing planar solid oxide fuel cells (SOFCs) and power systems for combined heat and power (CHP) units. The R&D work includes solid oxide fuel cell (SOFC) materials investigation, design and fabrication of single cells and stacks, and kW class SOFC CHP system development. Anode supported cells composed of Ni-YSZ/FL/YSZ/LSCF were enlarged up to $15{\times}15\;cm^2$ and stacks were manufactured using $10{\times}10\;cm^2$ cells and metallic interconnects such as ferritic stainless steel. The first-generation system had a 37-cell stack and an autothermal reformer for use with city gas. The system showed maximum stack power of about $1.3\;kW_{e,DC}$ and was able to recover heat of $0.57{\sim}1.2\;kW_{th}$ depending on loaded current by making hot water. The second-generation system was composed of an improved 48-cell stack and a prereformer (or steam reformer). The thermal management subsystem design including heat exchangers and insulators was also improved. The second-generation system was successfully operated without any external heat source. Under self-sustainable operation conditions, the stack power was about $1.3\;kW_{e,DC}$ with hydrogen and $1.2\;kW_{e,DC}$ with city. The system also recuperated heat of about $1.1\;kW_{th}$ by making hot water. Recently KEPRI manufactured a 2kW class SOFC stack and a system by scaling up the second-generation 1kW system and will develop a 5kW class CHP system by 2010.