alWhen an equivalent heatreduction under constant heat quantity is used as partial analysis

it is necessary to change workdone obtained into equivalent heareduction variation of the live steam through conversion factor λ

and then the relative variation of economic index can be evaluated. Combining with qγτ matrix equation

the calculation models of conversion factor corresponding to three kinds of auxiliary steamwater entering into and outgoing from the thermal system （i、e. from steam side or water side of the heaters

or with pure heat quantity） have been established

perfecting the application system of equivalent heatredution under constant quantity. Taking a homemade N 125135/550/550 unit as example

the adaptability of the models has been discussed.