System and method for cooling an aircraft fuel cell system

1. A system for cooling an aircraft fuel cell system comprising:

a first cooling circuit thermally coupled to a first fuel cell, in order to remove thermal energy generated by the first fuel cell during operation from the first fuel cell,

a first heat exchanger arranged in the first cooling circuit and adapted to transfer thermal energy, removed from the first fuel cell via the first cooling circuit, to the aircraft surroundings,

a second cooling circuit thermally coupled to a second fuel cell, in order to remove thermal energy generated by the second fuel cell during operation from the second fuel cell, and

a second heat exchanger arranged in the second cooling circuit and adapted to transfer thermal energy, removed from the second fuel cell via the second cooling circuit, to the aircraft surroundings, the first cooling circuit being thermally couplable to the second cooling circuit,

wherein the first fuel cell and the second fuel cell are adapted to operate at different powers, and wherein the first and the second cooling circuit are configured to remove the thermal energy which is generated by the fuel cell operated at a higher power and to transfer the thermal energy which is generated by the fuel cell operated at a higher power by means of the first and the second heat exchanger to the aircraft surroundings.

2. The system according to claim 1 , wherein at least one of the first and the second heat exchanger is integrated into an outer skin of the aircraft, is adapted to be flowed through with ambient air, and is provided with a plurality of cooling ribs at least in a region of an outer surface facing away from an interior of the aircraft.

3. The system according to claim 1 , wherein the first cooling circuit is thermally couplable to the second cooling circuit via a third heat exchanger.

4. The system according to claim 3 , wherein the third heat exchanger is thermally couplable to a device to be heated.

5. The system according to claim 4 , wherein the device to be heated is a fuel which flows through a fuel supply line which connects a fuel tank to at least one of the first and the second fuel cell.

6. The system according to claim 3 , wherein in the third heat exchanger, at least one tube forming a section of the first cooling circuit is connected in a heat-transferring manner to at least one tube forming a section of the second cooling circuit.

7. The system according to claim 6 , wherein in the third heat exchanger, the tubes connected in a heat-transferring manner to one another and forming a section of the first cooling circuit and a section of the second cooling circuit are arranged in a receiving space, through which fuel to be heated can flow.

8. A method for cooling an aircraft fuel cell system comprising the steps:

removing thermal energy from a first fuel cell by means of a first cooling circuit which is thermally coupled to the first fuel cell,

transferring the thermal energy, removed from the first fuel cell via the first cooling circuit, to the aircraft surroundings by means of a first heat exchanger arranged in the first cooling circuit,

removing thermal energy from a second fuel cell by means of a second cooling circuit which is thermally coupled to the second fuel cell,

transferring the thermal energy, removed from the second fuel cell via the second cooling circuit, to the aircraft surroundings by means of a second heat exchanger arranged in the second cooling circuit, the first cooling circuit being thermally coupled to the second cooling circuit,

wherein, when an aircraft equipped with the aircraft fuel cell system is in flight or is on the ground, the first and the second fuel cell are operated at different powers and the thermal energy which is generated by the fuel cell operated at a higher power is removed via the first and the second cooling circuit and transferred by means of the first and the second heat exchanger to the aircraft surroundings.

9. The method according to claim 8 , wherein, when the aircraft equipped with the aircraft fuel cell system is in flight, the thermal energy generated by the first or the second fuel cell is transferred to the aircraft surroundings exclusively via a plurality of cooling ribs which are provided in the region of an outer surface, facing away from an interior of the aircraft, of the first and the second heat exchanger.

10. The method according to claim 8 , wherein the first cooling circuit is thermally coupled to the second cooling circuit via a third heat exchanger.

11. The method according to claim 10 , wherein the third heat exchanger is thermally coupled to a device to be heated.

12. The method according to claim 11 , wherein the device to be heated is a fuel which flows through a fuel supply line which connects a fuel tank to at least one of the first and the second fuel cell.

13. The method according to claim 10 , wherein, in the third heat exchanger, at least one tube forming a section of the first cooling circuit is connected in a heat-transferring manner to at least one tube forming a section of the second cooling circuit.

14. The method according to claim 13 , wherein, in the third heat exchanger, the tubes connected in a heat-transferring manner to one another and forming a section of the first cooling circuit and a section of the second cooling circuit are arranged in a receiving space, through which fuel to be heated flows.