The absorption heat pump can effectively improve the power-heat decoupling phenomenon and enhance the operating flexibility of the combined heat and power unit(CHP). According to the operating principle of the absorption heat pump

the models of operating safety zone of the general CHP unit before and after the installation of absorption heat pumps are established. Taking a typical 330 MW CHP unit as an example

the operating safety zone is drawn

the influence of the coefficient of performance(COP) of the absorption heat pump on the heating supply capacity and operating safety zone of the unit is analyzed

and the change rules of peak regulation capacity with the heat extraction steam flow rate and COP of the heat pump are calculated. The results show that

the operating safety region and peak regulation capacity of the CHP unit have been improved significantly after the heat pump modification

and the peak regulation capacity increases with the COP

which is especially obvious when the heat steam flow rate is high.