US Patent 9555893 Blended flow air cycle system for environmental control

An aircraft air provision system includes a power turbine that receives bleed air at a first pressure and provides rotational energy to a shaft and outputs output air at an intermediate pressure. The system also includes a compressor coupled to the shaft that receives input air at a second pressure that is lower than the first pressure and outputs compressed air having a pressure equal to the intermediate pressure and a mix chamber coupled to outputs of both the power turbine and the compressor where the output air and the compressed air are mixed. The system also includes a cooling turbine coupled to the shaft and that is in fluid communication with an output of the mix chamber.