An environmental control system for an aircraft, comprising: a turbo-compressor assembly comprising: a first compressor having a first compressor inlet configured to receive ambient air and a first compressor outlet, a first turbine drivably connected to the first compressor, the first turbine having a first turbine inlet configured to receive bleed air from a gas turbine engine and a first turbine outlet, and a first heat exchanger having a first heat exchanger first side in fluid communication with the first turbine outlet through a first duct configured to receive the expanded bleed air though the first turbine outlet and provide the expanded bleed air to the first heat exchanger, a first heat exchanger second side, a first heat exchanger inlet in fluid communication with the first compressor outlet through a first conduit, and a first heat exchanger outlet; a ram air system having a first ram air inlet configured to receive ram air, a second ram air inlet in fluid communication with the first heat exchanger second side through a second duct that defines the second ram air inlet, and a second heat exchanger having a second heat exchanger first side in fluid communication with the first ram air inlet and the second ram air inlet and configured to receive a mixture of the ram air and the expanded bleed air, a second heat exchanger second side, a second heat exchanger inlet, and a second heat exchanger outlet; and an air cycle machine in fluid communication with the first heat exchanger outlet through a second conduit, the second heat exchanger inlet through a third conduit and the second heat exchanger outlet through a fourth conduit. a turbo-compressor assembly comprising: a first compressor having a first compressor inlet configured to receive ambient air and a first compressor outlet, a first turbine drivably connected to the first compressor, the first turbine having a first turbine inlet configured to receive bleed air from a gas turbine engine and a first turbine outlet, and a first heat exchanger having a first heat exchanger first side in fluid communication with the first turbine outlet through a first duct configured to receive the expanded bleed air though the first turbine outlet and provide the expanded bleed air to the first heat exchanger, a first heat exchanger second side, a first heat exchanger inlet in fluid communication with the first compressor outlet through a first conduit, and a first heat exchanger outlet; a first compressor having a first compressor inlet configured to receive ambient air and a first compressor outlet, a first turbine drivably connected to the first compressor, the first turbine having a first turbine inlet configured to receive bleed air from a gas turbine engine and a first turbine outlet, and a first heat exchanger having a first heat exchanger first side in fluid communication with the first turbine outlet through a first duct configured to receive the expanded bleed air though the first turbine outlet and provide the expanded bleed air to the first heat exchanger, a first heat exchanger second side, a first heat exchanger inlet in fluid communication with the first compressor outlet through a first conduit, and a first heat exchanger outlet; a ram air system having a first ram air inlet configured to receive ram air, a second ram air inlet in fluid communication with the first heat exchanger second side through a second duct that defines the second ram air inlet, and a second heat exchanger having a second heat exchanger first side in fluid communication with the first ram air inlet and the second ram air inlet and configured to receive a mixture of the ram air and the expanded bleed air, a second heat exchanger second side, a second heat exchanger inlet, and a second heat exchanger outlet; and an air cycle machine in fluid communication with the first heat exchanger outlet through a second conduit, the second heat exchanger inlet through a third conduit and the second heat exchanger outlet through a fourth conduit.