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# Heat Duty from Enthalpy and Specific Heat

## Heat Duty from Enthalpy and Specific Heat

(OP)
Hi,

In normal practice, heat duty is calculated using m*Cp*dT when it is sensible heat meaning no phase change however I wanted to know how about if we calculate the heat duty using enthalpy difference instead of specific heat. I understand normally we use enthalpy difference when to find the enthalpy of vaporization or condensation but how this affect when calculate for sensible heat duty.

The way I see is this enthalpy covers the rate of change of specific heat per degree of temperature change thus using enthalpy should and would produce the same result as using specific heat method.

Appreciate if anyone could share their generous experience. Thanks in advance!

### RE: Heat Duty from Enthalpy and Specific Heat

since heat capacity (for vapor and liquid) has not constant value (but temperature, pressure and composition dependence) one can integrate from p1,t1 to p2, t2 and calculate the difference in enthalpy, which is the method normally adopted in simulators.

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