Page 89 - HVAC Pump Handbook

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Piping System Friction
86 The Basic Tools

for piping networks was originated in the municipal water field; typi-
cal of this was the Hardy Cross method developed by Hardy Cross at
the University of Illinois in 1936. Development of such software for
contemporary computers has been completed by several universities
and software companies. An example of this software is that produced
by Donald Wood and James Funk at the University of Kentucky. This
software is known as KYPIPE Hydraulic Modeling Software.
Figure 3.15 provides a typical application of this procedure.
Although this figure is for municipal water distribution, a chilled
water distribution for a campus type installation is similar. The sys-
tem is divided into nodes, and the friction loss is computed for each
segment of pipe between nodes. A number of simulations are made
for various loads on the system so that the maximum possible fric-
tion loss can be ascertained for design of the chilled water pumps.
Table 3.18 provides the data for one of a number of simulations. This
procedure can be helpful in determining the type of chilled water
pumping system that should be used to achieve minimum energy
consumption.

TABLE 3.18 Tabulated Computer Results for Simulation No. 2
External Hydraulic Note Pressure Node
Node Node demand grade elevation head pressure
name title (gpm) (ft) (ft) (ft) (psi)
J-1 9.00 748.10 607.00 141.10 61.14
J-10 15.00 745.98 611.00 134.98 58.49
J-11 45.00 745.31 610.00 135.31 58.64
J-12 0.00 748.22 610.00 138.22 59.90
J-13 60.00 745.58 630.00 115.58 50.08
J-14 0.00 746.37 610.00 136.37 59.09
J-15 0.00 748.16 605.00 143.16 62.03
J-16 0.00 748.19 605.00 143.19 62.05
J-2 75.00 744.24 617.00 127.24 55.14
J-3 0.00 748.18 605.00 143.18 62.04
J-4 0.00 746.37 602.00 144.37 62.56
J-5 45.00 746.01 613.00 133.01 57.64
J-6 21.00 746.48 611.00 135.48 58.71
J-7 0.00 746.07 613.00 133.07 57.66
J-8 18.00 746.88 611.00 135.88 58.88
J-9 30.00 746.53 615.00 131.53 56.99
Pump-1 0.00 610.00 610.00 0.00 0.00
R-1 –– 610.00 605.00 5.00 2.17
T-1 –– 750.00 630.00 120.00 52.00
T-2 –– 749.00 625.00 124.00 53.73
Pump-1 0.00 748.18 610.00 138.18 59.88

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