converts directed molecular motion flow back into random thermal motion embodiments of the invention are distinguished by the arrangement of heat source and heat sink flows the number of disks pairs and additional structures for controlling heat transfer and gas flows in open embodiments the sink gas flow carrying the transferred heat is exhausted open embodiments are illustrated in fig1 3 4 7 and 8 in closed embodiments such as that shown in fig5 the toroidal recirculation of the heat sink gas through regions 5 4 15 and 14 requires that the heat transferred to the heat sink flow in region 4 be removed by transfer to an additional heat sink such as the stator 13 shown in fig5 closed embodiments allow the material used for the heat sink gas flow to be selected for desired thermal and viscous properties a first embodiment shown in fig1 and 2 is an open system comprising a single gas input and two gas outputs the device separates a single gas flow into two output flows one heated the other cooled as in all of the embodiments this embodiment includes a thermally conducting corotating disk pair 1 mounted on a common rotating hub 8 the hub 8 has a gas entrance 2 along its rotation axis 6 in this embodiment the source and sink flows enter through a common duct entrance 2 in all embodiments the heat sink flow is a gas thus because the source and sink flows enter this embodiment combined the heat source flow is also a gas the combined source and sink flows move inside the hub 8 parallel to the rotation axis 6 propelled by one or more axial annular turbines 9 the gas flowing axially in the duct is cooled by the thermal.