Environmental control system with liquid hydrogen fuel vaporization for a combustion engine
An aircraft environmental control system includes a tank holding liquid fuel, a heat exchanger, a first rotary machine, and a second rotary machine. The heat exchanger includes a cold side flow path downstream from the tank to vaporize the fuel using hot fluids from the aircraft. The heat exchanger includes a first hot side flow path and a second hot side flow path to cool the hot fluids. The first rotary machine includes a first compressor with a first impeller upstream from the second hot side flow path. The first rotary machine includes a first shaft tied to the first impeller and a first motor, which rotates the first impeller. The second rotary machine includes a second compressor with a second impeller downstream from the first compressor section. The second rotary machine includes a second shaft tied to the second impeller and a second motor, which rotates the second impeller.
1 . An environmental control system for an aircraft, the system comprising:
a fuel storage tank for holding liquid fuel;
a heat exchanger comprising:
a cold side flow path through the heat exchanger downstream from the fuel storage tank to vaporize the liquid fuel using hot fluids generated in the aircraft;
a first hot side flow path through the heat exchanger to cool a first hot fluid generated in the aircraft; and
a second hot side flow path through the heat exchanger to cool a second hot fluid generated in the aircraft;
a first rotary machine comprising:
a first compressor section upstream from the second hot side flow path through the heat exchanger, the first compressor section including a first compressor impeller;
a first shaft mechanically tied to the first compressor impeller; and
a first motor connected to the first shaft to rotate the first compressor impeller;
a second rotary machine comprising:
a second compressor section downstream from the first compressor section, the second compressor section including a second compressor impeller;
a second shaft mechanically tied to the second compressor impeller; and
a second motor connected to the second shaft to rotate the second compressor impeller;
a water extractor upstream from the second compressor section; and
a hot conditioned air duct downstream from the second compressor to deliver hot conditioned air to the aircraft; and
a cold conditioned air duct downstream from the second hot side flow path through the heat exchanger to provide cold air to the aircraft.
2 . The environmental control system of claim 1 , wherein the heat exchanger comprises:
a first heat exchanger compartment in an upstream portion of the cold side flow path, wherein the first heat exchanger compartment includes the first hot side flow path;
a second heat exchanger compartment directly downstream from the first heat exchanger compartment in the cold side flow path, wherein the second heat exchanger compartment includes the second hot side flow path; and
a third heat exchanger compartment directly downstream from the second heat exchanger compartment in the cold side flow path, wherein the third heat exchanger compartment includes a third hot side flow path downstream from the first compressor section and upstream from the second compressor section, and wherein the third hot side flow path cools a third hot fluid generated in the aircraft.
3 . The environmental control system of claim 2 , wherein the first hot fluid is exhaust gas from a gas turbine engine or an auxiliary power unit of the aircraft, wherein the second hot fluid is compressed air from the second compressor section, and wherein the third hot fluid is compressed air from the first compressor section.
4 . The environmental control system of claim 3 , and further comprising:
a valve upstream from the first hot side flow path in the first heat exchanger compartment to control an amount of exhaust gas moving through the first heat exchanger compartment.
5 . The environmental control system of claim 4 , wherein the liquid fuel is hydrogen, and wherein the valve is set to heat the fuel exiting the cold side flow path to a target temperature between 100° F. and 400° F.
6 . The environmental control system of claim 2 , and further comprising:
a first bypass duct with a first bypass valve downstream from the first compressor section to allow fluid to bypass the third hot side flow path through the heat exchanger.
7 . The environmental control system of claim 6 , and further comprising:
a second bypass duct with a second bypass valve downstream from the second compressor section to allow fluid to bypass the second hot side flow path through the heat exchanger;
wherein the first bypass valve is a modulating valve that is set so fluid downstream from the third hot side flow path is between about 33° F. and 36° F.; and
wherein the second bypass valve is a modulating valve that is set so fluid downstream from the second hot side flow path is between about 33° F. and 100° F.
8 . The environmental control system of claim 1 , and further comprising:
a pump between the fuel storage tank and the heat exchanger.
9 . The environmental control system of claim 1 , and further comprising:
a valve in the hot conditioned air duct to control an amount of the hot conditioned air delivered to the aircraft.
10 . The environmental control system of claim 1 , wherein first rotary machine further comprises:
a first turbine section including a first turbine impeller connected to the first shaft, wherein the first turbine impeller is downstream from the cold side flow path through the heat exchanger, and wherein the first impeller captures energy from fuel expansion to drive rotation of the first shaft and the first compressor impeller.
11 . The environmental control system of claim 1 , wherein the second rotary machine further comprises:
a second turbine section including a second turbine impeller connected to the second shaft, wherein the second turbine impeller is downstream from a pressurized space in the aircraft, and wherein the second turbine impeller captures energy from pressurized air exiting the pressurized space to drive rotation of the second shaft and the second compressor impeller.
12 . The environmental control system of claim 11 , wherein the pressurized space in the aircraft is a passenger cabin, and wherein the second turbine section is upstream from an overboard discharge port.
13 . An environmental control system for an aircraft with a combustion engine that burns hydrogen fuel, the system comprising:
a fuel storage tank for holding liquid hydrogen fuel;
a heat exchanger comprising:
a cold side flow path through the heat exchanger downstream from the fuel storage tank;
a first heat exchanger compartment in an upstream portion of the cold side flow path and including a first hot side flow path, wherein exhaust gas extracted from the engine moves through the first hot side flow path to heat the hydrogen fuel in the cold side flow path;
a second heat exchanger compartment directly downstream from the first heat exchanger compartment in the cold side flow path and including a second hot side flow path; and
a third heat exchanger compartment directly downstream from the second heat exchanger compartment in the cold side flow path and including a third hot side flow path;
a first rotary machine comprising:
a first compressor section upstream from the third hot side flow path through the heat exchanger, the first compressor section including a first compressor impeller;
a first shaft mechanically tied to the first compressor impeller; and
a first motor connected to the first shaft to rotate the first compressor impeller;
a first turbine section including a first turbine impeller connected to the first shaft, wherein the first turbine impeller is downstream from the cold side flow path through the heat exchanger and captures energy from the gaseous hydrogen fuel to drive rotation of the first compressor section;
wherein hot compressed air from the first compressor section moves through the third hot side flow path in the heat exchanger, and wherein heat from the compressed air is transferred to the hydrogen fuel in the cold side flow path of the heat exchanger; and
a second rotary machine comprising:
a second compressor section downstream from the first compressor section and upstream from the second hot side flow path through the heat exchanger, the second compressor section including a second compressor impeller;
a second shaft connected to the second compressor impeller; and
a second motor connected to the second shaft to rotate the second compressor impeller;
wherein hot compressed air from the second compressor section moves through the second hot side flow path in the heat exchanger, and wherein heat from the compressed air is transferred to the hydrogen fuel in the cold side flow path of the heat exchanger, and further wherein the hydrogen fuel exits the cold side flow path through the heat exchanger as a gas.
14 . The environmental control system of claim 13 , and further comprising:
a valve upstream from the first hot side flow path in the first heat exchanger compartment of the heat exchanger to control an amount of exhaust gas moving through the first heat exchanger compartment of the heat exchanger, wherein the valve is set to heat the hydrogen moving through the cold side flow path to a target temperature between 100° F. and 400° F.
15 . The environmental control system of claim 14 , wherein the valve allows a minimum amount of exhaust gas through the first hot side flow path to heat the hydrogen in the cold side flow path to the target temperature.
16 . The environmental control system of claim 13 , wherein the second rotary machine further comprises:
a second turbine section including a second turbine impeller connected to the second shaft, wherein the second turbine impeller is downstream from a pressurized aircraft cabin, and wherein the second turbine impeller captures energy from pressurized air exiting the pressurized space to drive rotation of the second shaft and the second compressor impeller.
17 . The environmental control system of claim 13 , and further comprising:
a pump between the fuel storage tank and the heat exchanger, wherein the pump includes an electric motor.
18 . An environmental control system for an aircraft with a combustion engine that burns hydrogen fuel, the system comprising:
a fuel storage tank for holding liquid hydrogen fuel;
a heat exchanger comprising:
a cold side flow path through the heat exchanger downstream from the fuel storage tank;
a first heat exchanger compartment in an upstream portion of the cold side flow path and including a first hot side flow path, wherein exhaust gas extracted from the engine moves through the first hot side flow path to heat the hydrogen fuel in the cold side flow path;
a second heat exchanger compartment directly downstream from the first heat exchanger compartment in the cold side flow path and including a second hot side flow path; and
a third heat exchanger compartment directly downstream from the second heat exchanger compartment in the cold side flow path and including a third hot side flow path;
a first rotary machine comprising:
a first compressor section upstream from the third hot side flow path through the heat exchanger, the first compressor section including a first compressor impeller;
a first shaft mechanically tied to the first compressor impeller; and
a first motor connected to the first shaft to rotate the first compressor impeller;
wherein hot compressed air from the first compressor section moves through the third hot side flow path in the heat exchanger, and wherein heat from the compressed air is transferred to the hydrogen fuel in the cold side flow path of the heat exchanger, and
a second rotary machine comprising:
a second compressor section downstream from the first compressor section and upstream from the second hot side flow path through the heat exchanger, the second compressor section including a second compressor impeller;
a second shaft connected to the second compressor impeller; and
a second motor connected to the second shaft to rotate the second compressor impeller;
a second turbine section including a second turbine impeller connected to the second shaft, wherein the second turbine impeller is downstream from a pressurized aircraft cabin, and wherein the second turbine impeller captures energy from pressurized air exiting the pressurized space to drive rotation of the second shaft and the second compressor impeller; and
wherein hot compressed air from the second compressor section moves through the second hot side flow path in the heat exchanger, and wherein heat from the compressed air is transferred to the hydrogen fuel in the cold side flow path of the heat exchanger.