AN ENVIRONMENTAL CONTROL SYSTEM

There is disclosed an environmental control system (110) for thermally conditioning air within an enclosed space (14), the system comprising: a refrigerant circuit (20) having a compressor, an indoor heat exchanger, an expansion device, and an outdoor heat exchanger (36). The system comprises an exhaust flowpath having a first inlet (428) for receiving an exhaust flow of thermally conditioned air from the enclosed space (14) and an outlet (422) for discharging the exhaust flow to an external environment (48). A heat transfer section (424) of the outdoor heat exchanger (36) is located in the exhaust flowpath, wherein the exhaust flowpath is for directing the exhaust flow of thermally conditioned air through the heat transfer section (424) of the outdoor heat exchanger (36).