Directing against the features of supercritical double reheat condensing unit to extract steam for heatsupply

and the split flow low pressure cylinder is separated out one cylinder for extracting steam to supply heat

the equivalent enthalpy drop of fresh steam from the double reheat extraction condensing unit and that of regenerative extractiion steam for each stage have been deduced by using the basic theory of equivalent enthalpy drop

and the economic behavior diagnosis method of thermodynamic system for supercritical double reheat extraction condensing unit being obtained through economic index’s transformation coefficient λ of the extraction unit. The reliability of ecomomic behavior analysing model has been verified by calculation of practical examples.