Analysis of a combined heating and power system based on high-temperature proton exchange membrane fuel cell and steam methane reforming: From energy, exergy and economic point of views

Hydrogen based combined heating and power system is a promising solution for green regional energy supplement. This work proposes a 50 kW-scale high-temperature proton exchange membrane fuel cell based combined heating and power system which is fueled by on-site hydrogen production. Organic Rankine Cycle is adopted to recover the thermal energy of fuel cell stack. The thermal energy integration of steam methane reforming and fuel cell is carried out, and a novel structure of steam methane reforming process for waste heat recovery is also proposed. The integrated system is simulated using Aspen Plus and MATLAB jointed model. The proposed system is evaluated from energy, exergy and economic aspects, and a new economic evaluation criterion (levelized cost of total energy) is put forward. The levelized cost of total energy reaches 0.0361 $/kWh, and the levelized cost of electricity which goes beyond many previous efforts is 0.0741 $/kWh. The total energy efficiency, electrical efficiency, total exergy efficiency, and electrical exergy efficiency achieve 60.98 %, 29.73 %, 30.33 %, and 28.68 %, respectively. The proposed system can provide 58.11 kW power output, and in the meantime generate 60 degrees C hot water at the flowrate of 0.3855 kg/s. The three components with the largest exergy destruction are fuel cell stack, evaporator, and combustor. Those components are the first to be optimized for improving the performance of integrated system.