On the basis of equivalent heat-drop theory under variation of heat quantity

a mathematical description concerning heat mass energy entering into or leaving from the thermodynamic system as absolute magnitude was deduced. This method is called pure heat quantity method

regarding the energy-level of live steam from the unit as a benchmark

and converting energy existing otherwhere in the unit to obtain the pure heat quantity grade coefficient "ξ j". According to the value of said "ξ j"

it is not only can judge the energy level in everywhere of the thermodynamic system to be high or low

but also discriminate the optimum points where heat quantity entering into or leaving from the thermodynamic system

so as to decrease the irreversible loss

enabling the thermodynamic system to run under optimal condition.