Energy and exergy analyses of an ethanol-fueled solid oxide fuel cell for a trigeneration system

Abstract

This paper examines an integrated SOFC (solid oxide fuel cell) system with an absorption chiller that uses heat recovery of the SOFC exhaust gas for combined cooling, heating, and power production (trigeneration) through energy and exergy analyses. The system consists of an ethanol reformer, SOFCs, an air pre-heater, a steam generator and a double-effect LiBr/H2O absorption chiller. Validation of the SOFC and absorption chiller models is performed by comparison with published data. To assess the system performance and determine the irreversibility in each component, a parametric study of the effects of changing the current density, SOFC temperature, fuel utilization ratio and SOFC anode recirculation ratio on the net electrical efficiency and the efficiency of heating cogeneration, cooling cogeneration and trigeneration is presented. The study shows that in the trigeneration plant, there is at least a 32% gain in efficiency, compared to the conventional power cycle. This study also demonstrates that the proposed trigeneration system represents an attractive option to improve the heat recovery and enhance the exergetic performance of the system.