Considering the exergy efficiency

this paper experimentally analyzed the energy saving effect of heat pump heating system recycling waste heat from circulating water in a subcritical 330 MW indirect air cooling unit with extraction heating.The results show that

with a relatively constant main steam flow rate and heat load

the total steam extraction rate under heat pump heating condition was dramatically lower than that under single heat net heating condition.The coefficient of performance(COP)of the heat pump in this unit is 1.631

and the exergy efficiency and generator power of the heating system increased by 8%and 10.729 MW respectively after the heat pump was applied.Assuming the annual average standard coal consumption of the unit for power generation is 330g/(kW ·h)and the annual heat supply time is3 816 h

the unit can save standard coal by 13 512 tevery year.