An environmental control system for an aircraft, the environmental control system comprising: a primary heat exchanger configured to transfer heat from an air source to a refrigerant in a generator flow and output an air flow ; an ejector comprising a nozzle in fluid communication with the primary heat exchanger, wherein a refrigerant outlet of the primary heat exchanger is connected to the nozzle of the ejector, and the ejector is configured to produce an intermediate refrigerant flow based on receiving the generator flow as a motive fluid and drawing a vapor refrigerant flow as a suction fluid; a refrigerant condenser in fluid communication with the ejector and configured to convert the intermediate refrigerant flow to a liquid refrigerant flow ; a pump in fluid communication with a refrigerant outlet of the refrigerant condenser upstream of an expansion device and configured to provide the refrigerant to the primary heat exchanger from a portion of the liquid refrigerant flow; the expansion device in fluid communication with the refrigerant condenser and an evaporator and configured to expand the liquid refrigerant flow prior to entering the evaporator; the evaporator in fluid communication with the ejector and the refrigerant condenser and configured to convert the liquid refrigerant flow to the vapor refrigerant flow and further in fluid communication with the air outlet of the primary heat exchanger and configured to produce a cooled evaporator air flow output based on the air flow from the primary heat exchanger; a turbine in fluid communication with an air outlet of the evaporator and configured to produce a cooled air output based on the cooled evaporator air flow output, wherein the turbine is further configured to drive one or more ram air fans and/or an air compressor; and a mixer in fluid communication with an air outlet of the turbine and configured to combine the cooled air output with a recirculated air flow to produce a supply air flow for the aircraft. a primary heat exchanger configured to transfer heat from an air source to a refrigerant in a generator flow and output an air flow ; an ejector comprising a nozzle in fluid communication with the primary heat exchanger, wherein a refrigerant outlet of the primary heat exchanger is connected to the nozzle of the ejector, and the ejector is configured to produce an intermediate refrigerant flow based on receiving the generator flow as a motive fluid and drawing a vapor refrigerant flow as a suction fluid; a refrigerant condenser in fluid communication with the ejector and configured to convert the intermediate refrigerant flow to a liquid refrigerant flow ; a pump in fluid communication with a refrigerant outlet of the refrigerant condenser upstream of an expansion device and configured to provide the refrigerant to the primary heat exchanger from a portion of the liquid refrigerant flow; the expansion device in fluid communication with the refrigerant condenser and an evaporator and configured to expand the liquid refrigerant flow prior to entering the evaporator; the evaporator in fluid communication with the ejector and the refrigerant condenser and configured to convert the liquid refrigerant flow to the vapor refrigerant flow and further in fluid communication with the air outlet of the primary heat exchanger and configured to produce a cooled evaporator air flow output based on the air flow from the primary heat exchanger; a turbine in fluid communication with an air outlet of the evaporator and configured to produce a cooled air output based on the cooled evaporator air flow output, wherein the turbine is further configured to drive one or more ram air fans and/or an air compressor; and a mixer in fluid communication with an air outlet of the turbine and configured to combine the cooled air output with a recirculated air flow to produce a supply air flow for the aircraft. <EOS>