Design and Performance Analysis of a Solid Oxide Fuel Cell/Gas Turbine (SOFC/GT) Hybrid System Used in Combined Cooling Heating and Power System

Abstract

With high efficiency and very low emissions, fuel cells have been one of the choices of research in current energy development. The Solid Oxide Fuel Cell (SOFC) is a high temperature type fuel cell. It has the characteristic of very high operating temperature 1,027°C (1,300K). The SOFC has the main advantage of very high performance efficiency (over 50%), but also has very high exhaust temperature. Current studies point out that the combination of SOFC and Gas Turbine (GT) can produce efficiency more than 60%. The exhaust temperature of this hybrid power system can be as high as 227–327°C (500–600K). With this waste heat utilized, we can further improve the overall efficiency of the system. A simulation program of SOFC/GT system and the introduction of the concept of Combined Cooling, Heating, and Power System (CCHP) have been used in this study. The waste heat of SOFC/GT hybrid power generation system was used as the heat source to drive an Absorption Refrigeration System (ARS) for cooling. This waste heat enables the SOFC/GT to generate electricity in the system while providing additional cooling and heating capacity. Therefore, we have a combined CCHP system developed using three major modules which are SOFC, GT, and ARS modules. The SOFC module was verified by our test data. The GT and SOFC/GT modules were compared to a commercial code and literature data. Both the single- and double-effect ARS modules were verified with available literature results. Finally, the CCHP analysis simulation system, which combines SOFC, GT, and ARS, has been completed. With this CCHP configuration system, the fuel usability of the system by our definition could be above 100%, especially for the double effect ARS. This analysis system has demonstrated to be a useful tool for future CCHP designs with SOFC/GT systems.