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RESOURCES

PUMP OPERATION AT 50 HZ
60 HERTZ50 HERTZ
GPMx 0.833 (17%)
HEAD0.694 (31%)
BHPx 0.580 (43%)
3500 RPM2900 RPM
1750 RPM1450 RPM
FARNENHEIT TO CELSIUS
-40 F-40.0 C
-30 F-34.4 C
-20 F-28.9 C
-10 F-23.3 C
0 F-17.8 C
10 F-12.2 C
20 F-6.7 C
30 F-1.1 C
40 F4.4 C
50 F10.0 C
60 F15.6 C
70 F21.1 C
80 F26.7 C
90 F32.2 C
100 F37.8 C
ETHYLENE GLYCOL
% VOLUMEFREEZE POINTSPECIFIC HEAT
10 %23 F0.957
20 %14 F0.924
30 %2 F0.897
40 %-13 F0.849
50 %-36 F0.809
PROPYLENE GLYCOL
% VOLUMEFREEZE POINTSPECIFIC HEAT
10 %26 F0.980
20 %18 F0.960
30 %7 F0.935
40 %-8 F0.895
50 %-29 F0.850
VOLUME
1 CUBIC FOOT7.481 GALLONS
2” DIA. PIPE.163 GAL/FT
2-1/2” DIA. PIPE.255 GAL/FT
3” DIA. PIPE.367 GAL/FT
4” DIA. PIPE.653 GAL/FT
6” DIA. PIPE1.470 GAL/FT
8” DIA. PIPE2.610 GAL/FT
10” DIA. PIPE4.100 GAL/FT
12” DIA. PIPE5.900 GAL/FT
COOLING TOWER TANK SIZING

In sizing a cooling tower pumping system, allow enough volume for draw down without causing pump cavitations. Draw down is the amount of water that is pumped out of the tank when the pump starts before water begins to return from the towers. Standard tank sizes allow 2 gallons per ton for draw down and towers located within 25 feet of the tank.

SYSTEM SIZEADDITIONAL VOLUME
TONSgallons per foot over 25 ft.
1 - 1008.8
101 - 30016.4
301 -50026.8

SIZING EXAMPLE

A 150-ton cooling tower is being located 50 ft. from the cooling tower pumping system. The minimum volume for the tank is calculated as follows:
Tank Volume = draw down volume + operating volume + distance
= 2 gals/ton x 150 tons + 1 gal/ gpm x 450 gpm + (50-25) feet x 16.4 gal/foot
= 300 + 450 + 410
= 1160 gallons required


WATER CHILLING SIZING
3 FACTORS BEFORE YOU BEGIN
  • Incoming water temperature
  • Chilled water temperature you require
  • Flow rate

GENERAL SIZING FORMULA
  1. Calculate temperature differential (rT°F) = incoming water temperature (°F) – required chilled water temperature
  2. Calculate BTU/HR. = gallons per hr. x 8.33 x rT°F
  3. Calculate tons of cooling capacity = BTU/HR ÷ 12,000
  4. Oversize chiller by 20% = tons x 1.2
  5. You have ideal size

Example, what size chiller is required to cool 70 GPM from 60°F to 48°F
  1. rT°F = 60° F – 48° F = 12° F
  2. BTU/HR = 70 gpm x 60 x 8.33 x 12°F = 419,832 BTU/HR
  3. Ton capacity = 419,832 BTU/HR ÷ 12,000 = 34.986 tons
  4. Oversize chiller = 34.986 x 1.2 = 41.9832
  5. 42-ton chiller is required
HEAT TRANSFER SYSTEMS
SIZE PUMP GPM PUMP PSI PUMP HP HEATER BTUH @ 275F HEATER SQ.FT. HEATER KW COOLER BTUH @ 120 F COOLER SQ.FT. COOLER KW COOLER HP/ZONE
2-1/2" 15 30 1.0 15,350 2.0 4.5 46,250 4 14 19
3-1/2" 30 30 1.0 30,710 4.0 9.0 101,250 8 30 41
4-1/2" 30 30 1.0 30,710 4.0 9.0 101,250 8 30 41
6" 50 30 1.5 30,170 4.0 9.0 187,500 15 55 76
8" 75 30 2.0 40,940 4.0 12.0 300,000 24 88 122
10" 75 30 2.0 61,420 6.0 18.0 300,000 24 88 122
12" 100 30 3.0 81,890 8.2 24.0 300,000 24 88 122
10" X 12" 75 30 2.0 81,890 8.2 24.0 450,000 36 132 183
15" X 12" 100 30 3.0 81,890 8.2 24.0 450,000 36 132 183
6" X 13" 10 25 1.0 15,350 2.0 4.5 46,250 4 14 19
12" X 24" 15 30 1.0 30,170 3.0 9.0 101,250 8 30 41
12" X 36" 15 45 1.0 61,420 6.0 18.0 187,500 15 55 76
18" X 48" 30 45 1.5 81,890 8.2 24.0 300,000 24 88 122
24" X 60" 60 45 3.0 122,830 12.5 36.0 450,000 36 132 183
26" X 84" 75 45 5.0 204,870 20.5 60.0 450,000 36 132 183
26" X 100" 100 45 5.0 255,900 25.6 75.0 550,000 44 161 224
6" X 13" 10 25 1.0 15,350 2.0 4.5 46,250 4 14 19
12" X 24" 15 30 1.0 30,710 3.5 9.0 101,250 8 30 41
12" X 36" 15 30 1.0 61,420 6.0 18.0 187,500 15 55 76
18" X 48" 30 45 1.5 81,890 9.0 24.0 300,000 24 88 122
24" X 60" 60 45 3.0 122,830 12.5 36.0 450,000 36 132 183
26" X 84" 75 45 5.0 204,720 21.0 60.0 450,000 36 132 183
26" X 100" 100 45 5.0 255,900 26.0 75.0 550,000 44 161 224