Development of kW Class SOFC Systems for Combined Heat and Power Units at KEPRI

Abstract

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 15×15 ㎠ and stacks were manufactured using 10×10㎠ 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 ㎾ e,DC and was able to recover heat of 0.57~1.2 ㎾ 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㎾ e,DC with hydrogen and 1.2 ㎾ e,DC with city. The system also recuperated heat of about 1.1 ㎾ th by making hot water. Recently KEPRI manufactured a 2 kW class SOFC stack and a system by scaling up the second-generation 1 ㎾ system and will develop a 5 ㎾ class CHP system by 2010.