50

60.3

2.9

54.5

65

76.1

2.9

70.3

80

88.9

3.2

82.5

100

114.3

3.6

107.1

125

139.7

3.6

132.5

bound the optimal diameters we have found. The bounding diameter that has the

lowest total cost will become our optimal discrete diameter. Obviously, it is only

necessary for us to compute the portion of the total cost that is dependent on pipe

diameter in making this decision. Table 9 gives the cost data for the bounding

discrete diameter for each of the pipe segments of our example. The costs are

calculated on a unit length basis using eq 2-23 divided through by *L*, the pipe length.

The portions of the total variable cost ascribable to each of the major component costs

are also given in Table 9. The parameter values of *I*1/*L *and *I*3/*L *used for each pipe

segment are the same as those given in Table 7.

Now we need to consider the constraints on our multiconsumer system as

derived earlier in Chapters 3 and 4. These are summarized in Chapter 5 in the *System*

at various points within the system. Since verification of satisfaction for these

constraints requires calculation of the pressure losses in the supply and return line,

we begin by doing so for each of the pipe segments. The pressure losses in the supply

or return pipes are calculated with eq 5-8 and 5-9 using the optimal discrete

diameters we have determined independently. The results are given in Table 10.

Satisfaction of the constraint of eq 4-2 at each of the consumers requires that we

d

0.0545

64.76

140.61

117.31

322.68

12.44

(6,1), (7,2),

(7,3), (5,4)

0.0825

83.24

212.85

109.11

405.20

4.14

(6,7)

(5,6)

0.1325

114.03

341.85

32.19

488.07

4.68

0.1071

98.65

276.32

222.03

597.00

12.51

(8,5)

65

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