Volume 4 fuel cells and hydrogen technology 4 10 – solid oxide fuel cells theory and materials

Volume 4 fuel cells and hydrogen technology 4 10 – solid oxide fuel cells theory and materials Volume 4 fuel cells and hydrogen technology 4 10 – solid oxide fuel cells theory and materials Volume 4 fuel cells and hydrogen technology 4 10 – solid oxide fuel cells theory and materials Volume 4 fuel cells and hydrogen technology 4 10 – solid oxide fuel cells theory and materials

4.10 Solid Oxide Fuel Cells: Theory and Materials A Tesfai and JTS Irvine, University of St Andrews, St Andrews, UK © 2012 Elsevier Ltd All rights reserved 4.10.1 Introduction 4.10.1.1 Fuel Cells 4.10.1.2 Thermodynamics 4.10.1.3 The Nernst Equation 4.10.1.4 The SOFC 4.10.1.4.1 Principles of operation 4.10.1.4.2 Advantages of SOFC over other types of fuel cell 4.10.1.5 SOFC Components 4.10.1.5.1 Electrolyte 4.10.1.5.2 Cathode 4.10.1.5.3 Anode 4.10.1.5.4 Interconnect 4.10.1.6 Example Systems 4.10.1.6.1 Introduction to CHP systems 4.10.1.6.2 Efficiency and efficiency limits 4.10.1.6.3 Heat and power load requirements for a typical UK home 4.10.1.6.4 Fuel cell-based micro-CHP systems 4.10.1.6.5 Performance characteristics 4.10.1.6.6 Fuel cell micro-CHP technical specifications and functional requirements 4.10.1.6.7 Efficiency 4.10.1.6.8 Durability 4.10.1.6.9 Fuel cell heat-to-power ratio and its advantages 4.10.1.6.10 Engineering methods to achieve a variable heat-to-power ratio 4.10.2 Conclusion Acknowledgment References Glossary Anode Where oxidation occurs, typically a fuel electrode Cathode Where reduction occurs, typically the air electrode Electrolyte Ion conducting membrane separating fuel and air electrodes 241 242 243 245 246 246 246 246 246 247 247 248 249 249 250 251 251 251 251 252 252 253 254 254 255 255 Fugacity Equal to the pressure of an ideal gas which has the same chemical potential as the real gas Gibbs free energy Thermodynamic potential that measures the ‘useful’ work Interconnect Gastight electrical connection between anode and cathode PEMFC Polymer electrolyte membrane fuel cell 4.10.1 Introduction The increasing demand for energy due to economic growth particularly in developing countries on one hand and increasingly energy-intensive lifestyles and trends on the other hand is posing a serious environmental sustainability challenge The problem of whether these competing demands for energy can be satisfied in a future of shrinking fossil fuel resources [1, 2] and global warming [3, 4] is causing a serious concern In recent years, this has intensified the search for more reliable and sustainable energy sources Currently, due to rapid depletion of oil reserves, natural gas and coal have been increasingly used as alternatives However, it is now widely accepted that long-term sustainable energy supply can only be achieved with the use of renewable energy sources (RESs) Some of the potential RESs are wind, solar, and tidal energy systems Electrochemical devices such as fuel cells will play an important role both to provide clean hydrogen gas for mobile application and also for converting fuel to energy more efficiently than conventional systems International experts agree that the optimal strategy and principles for addressing the energy and greenhouse gas (GHG) emissions is first to minimize energy losses through efficient use of fossil fuels; second to introduce cost-effective RESs – solar Comprehensive Renewable Energy, Volume doi:10.1016/B978-0-08-087872-0.00411-X 241