Reheating weakens the effectiveness of feedwater heat regenerative cycle. For the double-reheat power unit

the irreversible exergy loss of the regenerative heaters gets greater due to the higher superheat degree of steam extractions. Considering the parameters of steam extractions of the regenerative system

these overheats could be used by the boiler to heat the working fluid and feeding air

which will decrease the steam cycle absorption and increase the system efficiency equivalently. Therefore

with a reference case of 660 MW double-reheat power unit

the energy saving potentials of steam extractions overheat recovery were analyzed

based on the energy and exergetic balance models. The results show that

the superheat degrees of No.5 to No.10 steam extractions are very high

about 118 ℃ to 311 ℃. If the overheats of the No.5 to No.10 steam extractions could be recovered to the boiler

the standard coal consumption rate for power generation could be decreased by 3.59 g/(k W·h). Exergetic analysis show that the exergetic efficiency of No.5 to No.10 heaters were increased. Moreover

the overheat recovery system was preliminarily designed. The aim of this paper is to provide fundamentals for the optimization of doublereheat power plants.