US Patent 11628939 Fresh air ECS

An environmental control system of a vehicle includes a ram air circuit including a ram air shell having a ram air heat exchanger positioned therein, a dehumidification system arranged in fluid communication with the ram air circuit, a first compression device arranged in fluid communication with the dehumidification system, the first compression device including a first compressor, and a second compression device arranged in fluid communication with the ram air circuit. The second compression device includes a second compressor. A first medium is provided to the first compressor and to the second compressor in series.