Three wheel and simple cycle aircraft environmental control system

An environmental control system of an aircraft comprising:

• a ram air circuit including a ram air shell having at least one heat exchanger positioned therein, wherein the at least one heat exchanger includes a first heat exchanger, a second heat exchanger, and a third heat exchanger, the third heat exchanger being arranged in fluid communication with and located directly downstream from the first heat exchanger;
• at least one dehumidification system arranged in fluid communication with the ram air circuit;
• a compressing device arranged in fluid communication with the ram air circuit and the dehumidification system, the compressing device including a compressor and a first turbine operably coupled by a shaft;
• and
• an expansion device, located remotely from the compressing device and arranged in fluid communication with the ram air circuit and the at least one dehumidification system, the expansion device including a second turbine;
• wherein the environmental control system is operable in a plurality of modes and during operation in at least one of the plurality of modes, a first medium flows through the first heat exchanger and the third heat exchanger in series and is provided to the compressing device, a second medium is provided to the compressor and the expansion device, and a mixture of the first medium and the second medium is provided at an outlet of the environmental control system, wherein in the at least one mode of the plurality of modes the first medium is expanded within the first turbine, and the compressor is configured to receive energy from the first medium being expanded across the first turbine, the compressor being configured to compress the second medium.