Thermo-economic modeling of an atmospheric SOFC/CHP cycle: an exergy based approach

Sustainability is one of the challenging issues in electricity production systems. Recently, solid oxide fuel cell (SOFC) has been suggested for use in combined heat and power (CHP) systems. This application is introduced as a promising environmentally-friendly system according to the thermodynamic and electrochemical models. In this paper, an atmospheric SOFC/CHP cycle was analysed based on integrating exergy concepts, energy and mass balance equations. In this regard, a zero-dimensional energy and mass balance model was developed in engineering equation solver (EES) software. Two dimensionless parameters (the exergetic performance coefficient (EPC) for investigating the whole cycle, and exergetic efficiency for investigating the exergy efficiency of the main component of this cycle) were applied. Results show that efficiencies of the system have been increased substantially. The electrical efficiency, total efficiency and EPC of this cycle were similar to 54%, similar to 79% and similar to 58% respectively. Moreover, the CO2 emission is 19% lower than when compared with a conventional combined power cycle fed by natural gas. In addition, a dynamic economic evaluation was performed to extract the most sensitive parameters affecting the outputs: electricity sales price (ESP), equipment purchase cost and fuel cost. Furthermore, an electricity production cost of similar to 125 $ MW.h(-1) was attributed to our model, resulting in yet further cost reduction for widespread applications of this cycle.