Use of at least one output of a fuel cell system in a lavatory

1. A lavatory unit that uses at least one output of a fuel cell system,

wherein the at least one output comprises a combination of thermal energy and oxygen-depleted air that is directed from the fuel cell system into the lavatory unit to heat, dry, and sanitize surfaces of the lavatory unit, and

wherein the at least one output further comprises electrical energy that locks a door to the lavatory unit while the combination of thermal energy and oxygen-depleted air is being directed into the lavatory unit.

2. The lavatory unit of claim 1 , wherein the lavatory unit is further supplied by water generated by the fuel cell system.

3. The lavatory unit of claim 1 , wherein the fuel cell system is proximate the lavatory unit and water supplied by the fuel cell system is directed by at least one conduit to appropriate areas within the lavatory unit.

4. The lavatory unit of claim 1 , wherein the oxygen-depleted air is directed into the lavatory unit via shrouds or ducts in a floor or a ceiling of the lavatory unit.

5. The lavatory unit of claim 3 , wherein the water supplied by the fuel cell system is directed to a toilet or a faucet.

6. The lavatory unit of claim 1 , wherein the lavatory unit is configured for use in an aircraft.

7. The lavatory unit of claim 3 , further comprising a water treatment unit that disinfects the water before it is directed to the appropriate areas.

8. A method of using a fuel cell system to clean and power a lavatory unit for use in an aircraft comprising:

(1) locking a door to the lavatory unit using electrical energy generated by the fuel cell system;

(2) directing both thermal energy and oxygen-depleted air generated by the fuel cell system to the lavatory unit to sanitize, heat, deodorize and/or dry the lavatory unit or surfaces of the lavatory unit; and

(3) unlocking the door to the lavatory unit.

9. The method of claim 8 , further comprising directing water supplied by the fuel cell system to at least one of a toilet, a basin, or a shower.

10. The method of claim 9 , wherein gravity directs the water to the lavatory unit.

11. The method of claim 9 , wherein a mechanism directs the water to the lavatory unit.

12. The method of claim 9 , further comprising treating the water supplied by the fuel cell system before or after directing it to the lavatory unit.

13. The method of claim 8 , further comprising treating the oxygen-depleted air before directing it to the lavatory unit.

14. A method of using outputs of a fuel cell system to clean an aircraft lavatory unit comprising:

using electrical energy generated by the fuel cell system to lock a door to the lavatory unit and to light a status display indicating at least that the lavatory unit is unavailable for use or is being cleaned;

using at least one of water, thermal energy, or oxygen-depleted air generated by the fuel cell system to sanitize surfaces of the lavatory unit;

using at least one of the thermal energy or the oxygen-depleted air to dry the surfaces of the lavatory unit; and

deactivating the status display and unlocking the door to the lavatory unit.

15. The method of claim 14 , further comprising activating the status display to indicate that the lavatory unit has been cleaned.

16. The lavatory unit of claim 1 , wherein the electrical energy further lights a status display to indicate at least one of following statuses: (1) that the lavatory unit is being cleaned and (2) that the lavatory unit has been cleaned.

17. The lavatory unit of claim 1 , further comprising a status display that is configured to be lit by the electrical energy to indicate at least one of following statuses: (1) that the lavatory unit is being cleaned and (2) that the lavatory unit has been cleaned.