SPX Cooling Technologies Marley MH 05-116E - Manual (Page 15)

15
Fluid Cooler Operation
general:
The cold process fluid temperature obtained from an operating fluid cooler
will vary with the following influences:
1. Heat load: With the fan in full operation, if the heat load increases,
the cold process fluid temperature will rise. If the heat load reduces,
the cold process fluid temperature will reduce.
Note that the number of degrees (“range”) through which the fluid
cooler cools the process fluid is established by the system heat load
and the amount of fluid being circulated, in accordance with the follow-
ing formula—formula is only valid for 100% water as process fluid:
The fluid cooler establishes only the cold process fluid temperature
attainable under any operating circumstance.
2. air wet-bulb temperature: Cold process fluid temperature will also
vary with the wet-bulb temperature of the air entering the louvered
faces of the fluid cooler. Reduced wet-bulb temperatures will result
in colder process fluid temperatures. However, the cold process
fluid temperature will not vary to the same extent as the wet-bulb.
For example, a 20°F reduction in wet-bulb may result in only a 15°F
reduction in cold process fluid temperature.
3. Fluid flow rate: Increasing the process fluid flow rate (GPM) will cause
a slight elevation in cold process fluid temperature, while reducing
the fluid flow rate will cause the cold process fluid temperature to
decrease slightly. However, at a given heat load (see formula above),
process fluid flow reductions also cause an increase in the incoming
hot process fluid temperature and thermal range.
Under no circumstances should the recirculation water pump(s) be
cycled to control process fluid temperature. It is recommenced that
while process fluid is being circulated through the coil the fluid cooler
recirculation water system always be in operation.
Operation
Range – °F =
Heat Load (Btu/hr)
GPM x 500
or — in SI units
Range – °C =
Heat Load (kilowatts)
Liters/sec x 4.187
Note
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