An environmental control system for a vehicle comprising: a first inlet configured to receive a flow of a first medium; a second inlet configured to receive a flow of a second medium; a thermodynamic device including a compressor and at least one turbine operably coupled by a shaft, wherein the compressor and the at least one turbine are fluidly coupled to the first inlet, the compressor and the at least one turbine being arranged in parallel relative to the flow of the first medium such that a first portion (A1a) of the first medium is provided to the compressor and a second portion (A1b) of the first medium is provided to the at least one turbine; a cooling circuit including at least one cooling heat exchanger, the cooling circuit being fluidly connected to the second inlet; wherein the at least one cooling heat exchanger further comprises a primary heat exchanger and a secondary heat exchanger, characterised in that a flow inlet of the primary heat exchanger is arranged downstream from and is fluidly connected to a flow outlet of the secondary heat exchanger relative to the flow of the second medium; and in that the system further comprises at least one regeneration heat exchanger (36, 38) arranged downstream from the at least one cooling heat exchanger relative to the flow of the first medium; wherein the at least one regeneration heat exchanger further comprises a primary regeneration heat exchanger and a secondary regeneration heat exchanger, the primary regeneration heat exchanger being arranged downstream from the primary heat exchanger relative to the flow of the first medium, and the secondary regeneration heat exchanger being arranged downstream from the secondary heat exchanger relative to the flow of the first portion of the first medium. a first inlet configured to receive a flow of a first medium; a second inlet configured to receive a flow of a second medium; a thermodynamic device including a compressor and at least one turbine operably coupled by a shaft, wherein the compressor and the at least one turbine are fluidly coupled to the first inlet, the compressor and the at least one turbine being arranged in parallel relative to the flow of the first medium such that a first portion (A1a) of the first medium is provided to the compressor and a second portion (A1b) of the first medium is provided to the at least one turbine; a cooling circuit including at least one cooling heat exchanger, the cooling circuit being fluidly connected to the second inlet; wherein the at least one cooling heat exchanger further comprises a primary heat exchanger and a secondary heat exchanger, characterised in that a flow inlet of the primary heat exchanger is arranged downstream from and is fluidly connected to a flow outlet of the secondary heat exchanger relative to the flow of the second medium; and in that the system further comprises at least one regeneration heat exchanger (36, 38) arranged downstream from the at least one cooling heat exchanger relative to the flow of the first medium; wherein the at least one regeneration heat exchanger further comprises a primary regeneration heat exchanger and a secondary regeneration heat exchanger, the primary regeneration heat exchanger being arranged downstream from the primary heat exchanger relative to the flow of the first medium, and the secondary regeneration heat exchanger being arranged downstream from the secondary heat exchanger relative to the flow of the first portion of the first medium.