Air-cooled fuel-cell freeze-protection system
An air-cooled fuel-cell freeze-protection system for a rotorcraft using a controller to vary a heating system for an air-cooled fuel cell. The heating system heats supply air for the air-cooled fuel cell, and a butterfly valve varies a pressure of the supply air to the air-cooled fuel cell. The heating system can be an electric heater, a heat exchanger, or a combination of heater and heat exchanger.
1. An air-cooled fuel-cell freeze-protection system for a rotorcraft, comprising:
a controller;
an air-cooled fuel cell configured to be provided supply air from an inlet duct of the rotorcraft; and
a heating system configured to heat the supply air and comprising:
a heat exchanger;
a heat-exchanger duct; and
a heat-exchanger door;
wherein the heat exchanger is heated from exhaust air of the air-cooled fuel cell flowing through the heat-exchanger duct;
wherein the controller selectively varies the heating system by pivoting the heat-exchanger door.
2. The system of claim 1 ,
wherein a cross-sectional area of the heat-exchanger duct is equal to a cross-sectional area of the inlet duct.
3. The system of claim 1 ,
wherein a cross-sectional area of the heat-exchanger duct is unequal to a cross-sectional area of the inlet duct.
4. The system of claim 1 , wherein the heating system further comprises:
an electric heater;
wherein the supply air flows through the electric heater before entering the air-cooled fuel cell.
5. The system of claim 1 , wherein the heating system comprises:
an electric heater;
a heater housing; and
an electric fan configured to draw the supply air through the heater housing;
wherein the supply air flows through the electric heater before entering the air-cooled fuel cell; and
wherein the controller selectively varies the heating system by pivoting the heat-exchanger door and by varying a current to the electric heater.
6. The system of claim 5 ,
wherein the heater housing is removable from the rotorcraft.
7. The system of claim 1 , wherein the heating system further comprises:
an electric heater;
wherein the supply air flows through the electric heater before entering the air-cooled fuel cell; and
wherein the controller selectively varies the heating system by varying a current to the electric heater.
8. The system of claim 1 , further comprising:
a valve configured to vary a pressure of the supply air.
9. An air-cooled fuel cell freeze protection system for a rotorcraft, comprising:
a controller;
an air-cooled fuel cell configured to be provided supply air from an inlet duct of the rotorcraft; and
a heating system configured to heat the supply air and comprising:
an electric heater;
a heater housing;
an electric fan configured to draw the supply air through the heater housing;
wherein the supply air flows through the electric heater before entering the air-cooled fuel cell;
wherein the controller selectively varies the heating system by varying a current to the electric heater.
10. The system of claim 9 ,
wherein the heater housing is removable from the rotorcraft.
11. The system of claim 9 , further comprising:
a butterfly valve configured to vary a pressure of the supply air;
wherein the controller selectively varies the butterfly valve.
12. The system of claim 9 , wherein the heating system further comprises:
a heat exchanger;
a heat-exchanger duct; and
a heat-exchanger door;
wherein the heat exchanger is heated from exhaust air of the air-cooled fuel cell flowing through the heat-exchanger duct;
wherein a cross-sectional area of the heat-exchanger duct is equal to a cross-sectional area of the inlet duct; and
wherein the controller selectively varies the heating system by pivoting the heat-exchanger door.
13. The system of claim 9 , wherein the heating system further comprises;
a heat exchanger;
a heat-exchanger duct; and
a heat-exchanger door;
wherein the heat exchanger is heated from exhaust air of the air-cooled fuel cell flowing through the heat-exchanger duct;
wherein a cross-sectional area of the heat-exchanger duct is unequal to a cross-sectional area of the inlet duct; and
wherein the controller selectively varies the heating system by pivoting the heat-exchanger door.
14. The system of claim 9 , further comprising:
a butterfly valve configured to vary a pressure of the supply air;
wherein the heating system comprises:
a heat exchanger;
a heat-exchanger duct; and
a heat-exchanger door;
wherein the heat exchanger is heated from exhaust air of the air-cooled fuel cell flowing through the heat-exchanger duct;
wherein a cross-sectional area of the heat-exchanger duct is equal to a cross-sectional area of the inlet duct;
wherein the controller selectively varies the butterfly valve; and
wherein the controller selectively varies the heating system by pivoting the heat-exchanger door.
15. The system of claim 9 , further comprising:
a butterfly valve configured to vary a pressure of the supply air;
wherein the heating system comprises:
a heat exchanger;
a heat-exchanger duct; and
a heat-exchanger door;
wherein the heat exchanger is heated from exhaust air of the air-cooled fuel cell flowing through the heat-exchanger duct;
wherein a cross-sectional area of the heat-exchanger duct is unequal to a cross-sectional area of the inlet duct;
wherein the controller selectively varies the butterfly valve; and
wherein the controller selectively varies the heating system by pivoting the heat-exchanger door.