On the basis of a reference 300 MW split recompression single reheat supercritical carbon dioxide(S-CO2) Brayton cycle

a new S-CO2 Brayton cycle system is proposed

in which the fresh air is firstly preheated by the waste heat of working medium in the cooler. By calculating the energy consumption distributions of both the reference and new systems

the reasons for the reduction of coal consumption in the new system are revealed and the preliminary economic performance analysis is carried out. The results show that

boiler equipment accounts for 81.72% of the additional coal consumption in the new system

then is the cooler. Compared with the reference system

the new system can effectively reduce the standard coal consumption rate of power generation. When the air temperature at the air preheater inlet is heated to 80 ℃ in the new system

the coal consumption can be saved by 4.53 g/(kW·h) compared with the reference system

and the static investment payback time is around 6.98 year. The reduction of standard coal consumption rate of new system is mainly due to the reduction of additional coal consumption of both the cooler and boiler.