at this condition, it will be satisfied at the lower temperature conditions.
For a return temperature of 55C, the saturation pressure is 1.576 104 N/m2
(Reynolds and Perkins 1977). The sum of this and our safety margin is 1.157
105 N/m2. By examining the return pressures in Table 14, we see the constraint of
eq 4-23 is satisfied at all points in the return piping.
Now we look at the two constraints on the pressure in the return line at the heating
plant, eq 4-24 and 4-25. We see that, for the parameter values chosen, eq 4-24 will
dominate. Equation 4-24 requires that the pressure in the return line at the heating
plant be greater than 2.0 105 N/m2. The pressure in the return line at node number
8, which is our heating plant node, is given as 287,256 N/m2 in Table 14, so we see
this constraint is satisfied as well. Thus, our design has satisfied all the constraints