Using bleed air to supply outside air to a cabin
A method of operating an environmental control system of an aircraft includes providing a first medium to the environmental control system including a compressor and a turbine and extracting work from a second medium provided to a second turbine operably coupled to the compressor to drive the compressor. The first medium is provided to the compressor and the turbine sequentially. In a first mode of operation, the first medium to be provided to a downstream load is output from the turbine and in a second mode of operation, at least a portion of the first medium to be provided to the downstream load bypasses the turbine.
1. A method of operating an environmental control system of an aircraft comprising:
providing a first medium to the environmental control system including a compressor and a turbine, wherein the first medium is provided to the compressor and the turbine sequentially;
conditioning the first medium output from the compressor at a heat exchanger, the heat exchanger being located downstream an outlet of from the compressor and upstream from an inlet of the turbine; and
extracting work from a second medium provided to a second turbine operably coupled to the compressor to drive the compressor;
wherein in a first mode of operation, the first medium to be provided to a downstream load is output from the turbine and in a second mode of operation, at least a portion of the first medium to be provided to the downstream load bypasses both the heat exchanger and the turbine.
2. The method of claim 1 , wherein the environmental control system is transformed from the first mode of operation to the second mode of operation by opening a bypass valve.
3. The method of claim 2 , wherein opening the bypass valve diverts a flow of the first medium output from the compressor around the turbine.
4. The method of claim 1 , wherein in a third mode of operation, at least a portion of the first medium output from the compressor is provided to the second turbine.
5. The method of claim 4 , wherein the environmental control system is transformed from the first mode of operation to the third mode of operation by opening a second bypass valve.
6. The method of claim 4 , wherein in the third mode of operation the second medium and the at least a portion of the first medium output from the compressor are provided to the second turbine simultaneously.
7. The method of claim 1 , wherein providing the second medium to the environmental control system includes drawing bleed air from an engine of the aircraft.
8. The method of claim 1 , wherein providing the first medium to the environmental control system includes drawing fresh air from outside the aircraft.
9. The method of claim 1 , further comprising exhausting the second medium output from the second turbine overboard.
10. The method of claim 1 , further comprising exhausting the second medium output from the second turbine into a ram air circuit.