For calculating  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated, the effectiveness-NTU method has the advantage of requiring the knowledge of  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated, and not those  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated.

The  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated ε of the exchanger, is defined as the ratio between the  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated and the  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated.

ε measures the "temperature" effectiveness of the exchanger, i.e. the  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated in temperature between the fluids  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated to the fluid with the lower heat capacity rate.

NTU, or  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated, measures the  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated of the fluid whose capacity rate is lower.

This is an indicator of the quality of the equipment: the  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated, the  ability of the exchanger for changing the temperatureat the outleteffectivenessfluid inlet temperaturesfraction of the maximum differenceheat exchangersheat flux actually transferredmaximum possible fluxmore efficient the heat exchangermore it allows for heating or coolingnumber of transfer unitswhich is communicated a fluid with a low temperature difference compared with the other.