ABSTRACT

This chapter focuses on fuel cell, including the basic principle of operation, system composition, and balance of plants, the performance and the design considerations, as well as the state-of-the-art technology. In a fuel cell, the chemical energy of a fuel and an oxidant is directly converted into electrical energy, which is exhibited in terms of cell potential and electrical current output. The maximum possible electrical energy output and the corresponding electrical potential difference between the cathode and the anode are achieved when the fuel cell is operated under thermodynamically reversible conditions. Phosphoric acid fuel cell (PAFC) is the most commercially developed fuel cell, operating at intermediate temperatures. PAFCs are being used for combined heat and power applications with high energy efficiency. The maximum possible efficiency for fuel cell may be compared with the Carnot efficiency, the maximum possible efficiency for heat engines against which fuel cell is competing for commercial success.