is further coupled to point 30 along flow line 64 thus it may receive any discharge from separator 22 of a gaseous vapor working fluid resulting when the preferred medium as a matter of convenience is of a binary composite or multi component substance thereafter the working fluid becomes partially mixed and passed through distillation generally designated d1 the composite working fluid is principally in thermodynamic equilibrium the fluid conduit 104 passing in heat exchange through d1 may as a practical matter originate from any or all the series of evaporators thereby offering temperature ranging from the lowest temperature of the series at evaporator 160 1 and including the highest temperature as fig1 of the drawings illustrates emanating from evaporator 160 3 the higher boiling liquid component at point 23 may be further distilled at d1 to bring it into temperature equilibrium at 25 as illustrated in the alternate embodiment shown in fig2 in addition the condensed liquid working fluid may through 24 to 19 undergo a pressure reduction through valve 19 thereby permitting to be recycled into the original low pressure spent composite working fluid thereby regenerating the initial composite working fluid stream fig1 and fig2 of the drawings show a continuous heat source originating at 158 and flowing through the composite vapor generator or boiler designated 165 to point 159 this creates a first highest temperature zone in the super heater stage 164 a second highest temperature zone in the evaporator generally designated 160 3 a third highest temperature zone in the evaporator generally designated 160 2 and a fourth highest temperature zone in the evaporator generally designated 160 1 it will then be readily apparent that with each evaporator coupled in succession with check valves 72 interposed between these successive evaporator stages.