Degrees of freedom for Steam heater

Degrees of freedom for Steam heater

Degrees of freedom

The degrees of freedom of a process define the maximum number of independently acting automatic controllers that can be placed on a process 

Degrees of freedom = number of variables – number of equations

Steam heater

In this case there are four process variables and one defining equation is 

[ HsWs= CpW(T2-T1)]

Four process variables are two flow and two temperatures

hence the number of degrees of freedom of that process is three. 

Thus, a maximum of three automatic controllers can be placed on it.