Proton exchange membrane fuel cells heat recovery opportunities for combined heating/cooling and power applications

The present paper provides a comprehensive review of heat recovery opportunities for proton exchange membrane fuel cells. A significant amount of heat is generated by these fuel cells while operating that is equivalent to ~45 to 60% of the total energy content of hydrogen entering the cells. The generated heat must be removed effectively from the stack by using a properly-designed cooling system in order to prolong its lifetime and maintain its performance. Applying proper thermal management strategies and capturing opportunities for fuel cell heat recovery can add significant values to a fuel cell system in terms of size, costs, and its overall energy efficiency. The heat generated by proton exchange membrane fuel cells can be captured and used for a range of combined heating/cooling and power applications: i.e. combined heat and power, combined cooling and power, or combined cooling heat and power solutions. The heat generated by a fuel cell stack also provides opportunities for its integration with organic Rankine cycles, thermoelectric generators, and thermally regenerative electrochemical cycles for power cogeneration applications. Furthermore, the heat recovered from a fuel cell can be used for self-servicing the system such as enhancing the hydrogen discharge rate of metal hydride canisters (supplying hydrogen to the stack) or preheating inlet air and hydrogen to improve performance of the fuel cell. The present paper also helps identify the research gaps in this area and provides direction on future studies on thermal management and integrated heat recovery solutions for proton exchange membrane fuel cells.