System and method for cooling a fuel cell assembly

The invention relates to a system for cooling a fuel cell assembly () of a transport vehicle, such as an aircraft, comprising: a cooling fluid circulation loop (); a cooling heat exchanger () configured to be able to provide heat exchanges between said loop () and a channel () for circulating cooling air (); a variable-speed pump () for supplying said cooling loop with cooling fluid as a function of a measurement representative of the cooling need of said fuel cell assembly; for each fuel cell () of said cell assembly, a 3-way valve () for regulating the flow rate of cooling fluid supplying this cell as a function of a measurement representative of the cooling need of this cell.