UFC 3-240-13FN
25 May 2005
Figure 4-15. Effect of COC on Makeup Requirement
Makeup, % of Circulation Rate
0
1
2
3
4
5
6
7
8
9
0
1
5.5C/10F DT
2
11C/20F DT
16.5C/30F DT
3
4
5
6
7
8
9
10
6.3
12.6
18.9
25.2
31.5
37.8
44.2
50.5
56.8
[100]
[200]
[300]
[400]
[500]
[600]
[700]
[800]
[900]
Makeup, Liters per Second [GPM]
(Basis 631 Liters per Second [10,000 GPM] Circulation Rate)
4-2.1.3
Relationship Between Blowdown, Evaporation, and COC. You can use
the cooling water evaporation loss to calculate the blowdown rate that must be
maintained to operate at a selected COC. The relationship between blowdown,
evaporation, and COC is represented with this equation:
EQUATION
B = E (C - 1)
(22)
where
B = blowdown, liters per day or liters per second (gpd or gpm)
E = evaporation, liters per day or liters per second (gpd or gpm)
C = COC, no units
EXAMPLE: A cooling tower evaporates 37.8 liters per second (600 gallons per minute)
and operates at 4 COC:
105
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