Optimal thermo-economic design of a PAFC-ORC combined power system

초록

Phosphoric acid fuel cells (PAFCs) are appropriate for applications that require high-quality power because of their high reliability. We propose a system that combines an 11 MW PAFC and an organic Rankine cycle (ORC). The ORC recovers waste heat from the PAFC and produces power. The performance and economics of the system were simulated with changes in the working parameters of the PAFC and ORC to find economically optimal design conditions. The optimal working conditions with the best economic performance were found between the operating conditions with the maximum power and the maximum efficiency. The best design conditions were predicted for various ORC working fluids: the power was between 14.63 and 15.51 MW, and the efficiency was between 40.35 and 42.75 %. The maximum improvements of the power and efficiency over the stand-alone PAFC system were 41.77 % and 47.18 %, and the estimated payback period was around 5.50 years.

키워드