Environmental control system trim air heat exchanger

An environmental control system comprising:

• at least one environmental control system pack having at least one inlet, a trim outlet and a primary outlet, wherein a trim medium is output from the trim outlet and a first medium is output from the primary outlet;
• a mixing manifold having an inlet and at least one outlet, the inlet of the mixing manifold being fluidly connected to the primary outlet of the at least one environmental control system pack;
• a trim heat exchanger fluidly connected to the trim outlet and the at least one inlet of the at least one environmental control system pack, wherein within the trim heat exchanger the trim medium is arranged in a heat exchange relationship with a second medium, the second medium output from the trim heat exchanger being provided to the at least one inlet of the at least one environmental control system pack and the trim medium output from the trim heat exchanger being mixed with a flow output from the at least one outlet of the mixing manifold.