EVAPORATIVELY COOLED FUEL CELL SYSTEMS WITH CATHODE EXHAUST TURBINE BOOST

The present disclosure provides methods for turbine-based energy recovery from exhaust streams in fuel cell systems. The fuel cell systems can include an expansion turbine (200) arranged to capture electrical energy from cathode exhaust streams. The cathode exhaust streams (151a, 151b, 151c) can be flowed through an intercooler (250) to be preheated prior to entering the expansion turbine (200), with heat added by transferring heat from a compressed air flow. The methods can include operating the fuel cell system in a temperature-boost mode that includes reducing fan operation related to a condenser to reduce liquid recapture from an exhaust stream and increase exhaust stream temperature for use in turbine-based energy recovery. The temperature-boost mode can be controlled to limit the operation time based on coolant fluid levels in the fuel cell system.