FIELD: thermal engineering. SUBSTANCE: condensate K of combined-cycle plant 2 is degassed by heating in feedwater tank 26 and supplying it to heated condensate KТ; feedwater S is taken off for heat-transfer surfaces 6, 42, 52,60 inserted in steam loop 3 of steam turbine 2b and heated by flue gas AG coming from gas turbine 2a. Novelty is that heat-carrying agent HZ for condensate K is partial flow t1 of heated condensate KТ or partial flow t4 of heated feedwater SТ. To this end, device implementing proposed method has low-pressure economizer 42 connected to waste- heat steam generator 1 downstream of condensate heater 6 through feedwater tank 26; condensate heater 6 or low-pressure economizer 42 has outlet pipeline 34 or, respectively, 74, on outlet side of feedwater tank 26. EFFECT: improved efficiency. 9 cl, 3 dwg
