Phosphoric acid fuel cell

Definition

A phosphoric acid fuel cell (PAFC) is a type of electrochemical device that converts chemical energy from hydrogen and oxygen into electrical energy, utilizing phosphoric acid as the electrolyte. These fuel cells operate at relatively high temperatures, around 150 to 200 degrees Celsius, which allows for improved efficiency and durability compared to other types of fuel cells. PAFCs are particularly suited for stationary applications, providing reliable power for commercial and industrial use.

5 Must Know Facts For Your Next Test

1. Phosphoric acid fuel cells have a longer lifespan compared to other types of fuel cells, often exceeding 40,000 hours of operation.
2. These fuel cells are less sensitive to impurities in hydrogen fuel, allowing them to operate efficiently with lower purity levels than proton exchange membrane (PEM) fuel cells.
3. PAFCs can achieve an electrical efficiency of around 40% and can be combined with a heat recovery system to reach overall efficiencies of up to 90%.
4. They are commonly used in applications such as distributed generation systems, combined heat and power (CHP) systems, and backup power supplies.
5. Phosphoric acid fuel cells are generally larger and heavier than PEM fuel cells, making them less suitable for portable applications but ideal for stationary installations.

Review Questions

• How does the operating temperature of phosphoric acid fuel cells influence their efficiency and application?
  • The operating temperature of phosphoric acid fuel cells, which is typically between 150 to 200 degrees Celsius, allows these cells to achieve higher efficiencies compared to many low-temperature fuel cells. The elevated temperature helps in reducing the reaction kinetics barriers and enables better thermal management. As a result, PAFCs can be used effectively in stationary applications where reliable and continuous power is needed, making them suitable for commercial and industrial settings.
• What advantages do phosphoric acid fuel cells offer over other types of fuel cells, particularly regarding impurities in hydrogen?
  • Phosphoric acid fuel cells possess a significant advantage over other types like proton exchange membrane (PEM) fuel cells when it comes to tolerating impurities in hydrogen fuel. While PEM fuel cells require high-purity hydrogen to function optimally, PAFCs can operate efficiently with lower purity levels. This makes PAFCs more practical for applications where the cost and availability of pure hydrogen may be a concern, thus broadening their applicability in real-world scenarios.
• Evaluate the role of phosphoric acid fuel cells in the transition towards a hydrogen economy and their potential impact on energy sustainability.
  • Phosphoric acid fuel cells play a crucial role in the transition towards a hydrogen economy by providing efficient and reliable means of converting hydrogen into electricity. Their ability to utilize lower-purity hydrogen makes them an attractive option for distributed energy generation, which can help reduce reliance on fossil fuels. Additionally, the combination of high electrical efficiency and potential for waste heat recovery aligns with sustainability goals, supporting initiatives aimed at reducing carbon emissions and enhancing energy resilience in various sectors.

Related terms

Electrolyte: A substance that conducts electricity through the movement of ions, allowing the chemical reactions necessary for the fuel cell to take place.

Fuel Cell Stack: A series of individual fuel cells stacked together to increase the overall power output and efficiency of the system.

Hydrogen Economy: A vision for a future where hydrogen serves as a primary energy carrier, promoting sustainable energy systems and reducing reliance on fossil fuels.