Exergy, Eonomic, and Environmental Analysis of a Trigeneration System Based on a Solid oxide Fuel Cell and Gasifier

A new combined system based on a biomass gasifier, SOFC and single effect Li-Br refrigeration cycle for generation of power, heating and cooling is proposed and assessed thermodynamically. With the aid of the Engineering Equation Solver software (EES) Exergy analysis is conducted to determine the irreversibilities in system components. In addition, an environmental impact assessment is performed for each of the three cases in combined system based on each cycle of the proposed system. Also an economic analysis to find unit product cost is carried out. To understand the system performance more comprehensively, a parametric study is performed to investigate the effect of several important design parameters on the net power output as well as exergy efficiency of the system. The results demonstrate that an increase of 75oC in stack temperature difference results in 8.99% and 17.47% increases for the exergy and energy efficiencies, respectively. Also net power output is maximized at certain values of current density and fuel utilization factor. In addition, compared to the SOFC system (power generation system alone), the exergy efficiency of the combined system is 12.04% higher and the CO2 emission of the combined system is 62.34% lower. Results demonstrate that power unit product cost becomes 15.76 $/GJ.