# US 11,999,491 B2 · Aircraft environmental control system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,999,491 B2 - Document ID: US11999491B2 - Status: Granted - Kind: B2 - Application number: 17/390,188 - Filed: 2021-07-30 - Published: 2022-02-03 - Granted: 2024-06-04 - Earliest claimed: 2020-07-30 - Assignees: Hamilton Sundstrand Corporation - Applicants: Hamilton Sundstrand Corporation - Inventors: Louis J. Bruno; Tony Ho; Aiden Coutin - Web page: https://patentgrep.com/patent/US11999491B2 ## CPC - B64D 13/06: the air being conditioned (pressurising B64D13/02) - B64D 13/08: the air being heated or cooled - F25B 9/004: {the refrigerant being air} - F25B 9/06: using expanders (F25B9/10 takes precedence) - B64D 2013/0618: {with arrangements for reducing or managing bleed air, using another air source, e.g. ram air} - B64D 2013/064: {comprising more than one system, e.g. dual systems} - B64D 2013/0648: {with energy recovery means, e.g. using turbines} - B64D 2013/0662: {with humidity control} - Y02T 50/50: On board measures aiming to increase energy efficiency - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract An environmental control system includes a plurality of inlets for receiving a plurality of mediums including a first medium and a second medium and an outlet for delivering a conditioned form of the second medium to at least one load of the aircraft. A ram air circuit includes a ram air shell having at least one heat exchanger positioned therein and a dehumidification system is arranged in fluid communication with the ram air circuit. A compression device is arranged in fluid communication with the ram air circuit and the dehumidification system. The compression device includes a compressor and a plurality of turbines including a first turbine and a second turbine operably coupled by a shaft. An outlet of the first turbine is directly coupled to an inlet of the second turbine, such that the first medium is provided to the first turbine and the second turbine in series. ## Claims ### Claim 1 An environmental control system of an aircraft comprising: a plurality of inlets for receiving a plurality of mediums including a first medium and a second medium; an outlet for delivering a conditioned form of the second medium to at least one load of the aircraft; a ram air circuit including a ram air shell having at least one heat exchanger positioned therein; a dehumidification system arranged in fluid communication with the ram air circuit; and a compression device arranged in fluid communication with the ram air circuit and the dehumidification system, the compression device including a compressor and a plurality of turbines including a first turbine and a second turbine operably coupled by a shaft, wherein an outlet of the first turbine is directly coupled to an inlet of the second turbine, such that the first medium is provided to the first turbine and the second turbine in series and an outlet of the second turbine is fluidly coupled to the ram air circuit such that the first medium output from the second turbine is exhausted into the ram air circuit. ### Claim 2 (depends on 1) The environmental control system of claim 1, wherein the compressor is operable to receive a second medium, and the compressor is driven by work extracted from the first medium within the first turbine and the second turbine. ### Claim 3 (depends on 1) The environmental control system of claim 1, wherein the first medium is bleed air and the second medium is fresh air. ### Claim 4 (depends on 1) The environmental control system of claim 1, wherein plurality of turbines further comprises a third turbine, wherein an inlet of the third turbine is arranged in fluid communication with an outlet of the compressor. ### Claim 5 (depends on 1) The environmental control system of claim 1, wherein the plurality of mediums includes a third medium and a flow of the third medium is arranged in fluid communication with the inlet of the second turbine. ### Claim 6 (depends on 5) The environmental control system of claim 5, wherein the second first medium and the third medium are mixed at a mixing point located upstream from the second turbine. ### Claim 7 (depends on 5) The environmental control system of claim 5, wherein the first medium and the third medium are mixed at a mixing point located at an outlet of the second turbine. ### Claim 8 (depends on 7) The environmental control system of claim 7, wherein the second turbine is a dual entry turbine having a first nozzle and a second nozzle, the outlet of the first turbine being directly coupled to the first nozzle, and the flow of third medium being connected to the second nozzle. ### Claim 9 (depends on 1) The environmental control system of claim 1, wherein a flow output from the second turbine is used to cool a flow within the dehumidification system. ### Claim 10 (depends on 9) The environmental control system of claim 9, wherein the ram air circuit further comprises a divider positioned to separate the ram air shell into a first region and a second region, wherein two distinct mediums are configured to flow through the first region and the second region, respectively. ### Claim 11 (depends on 10) The environmental control system of claim 10, wherein the at least one heat exchanger includes a first portion arranged within the first region and a second portion arranged within the second region, the first portion and the second portion being integrally formed. ### Claim 12 (depends on 10) The environmental control system of claim 10, wherein the at least one heat exchanger includes a first heat exchanger arranged within the first region and a second, distinct heat exchanger arranged within the second region, the second heat exchanger being arranged in fluid communication with an outlet of the first heat exchanger.