SPX Cooling Technologies MARLEY CLASS 800 - Manual (Page 4)

4
General
A cooling tower, like any heat exchanger, exchanges all heat imposed upon
it from one fluid to another fluid. For a cooling tower, heat from the water is
put into the air. The plant process replenishes the heat to the water, typically
at another heat exchanger such as a condenser. A cooling tower differs from
many heat exchangers in that heat is transferred in two forms—sensible and
latent heat. As heat is transferred from the water, the air temperature increases
(sensible) and the air’s water content, or humidity, also increases (latent). As
the heat load, inlet air wet-bulb temperature, or airflow on a cooling tower
changes, the cooling tower will respond by finding a new equilibrium with the
process. The cooling tower will still dissipate all the heat from the process,
but at new water temperatures.
The cooling tower cold water temperature is the supply water temperature
to the condenser, and changes in the cold water temperature usually affect
efficiency of the plant output. Although the reduced cold water temperatures
that result from maximum fan power utilization are usually beneficial to plant
output, the amount of fan power affects the cost of running the cooling tower.
As these variables interact on a cooling tower, the operator must find the
proper trade-off between these opposing forces.
These instructions will assist in obtaining efficient, long life from Marley cooling
equipment. Direct questions concerning tower operation and maintenance to
your Marley sales office or representative. Always include your tower serial
number when writing for information or ordering parts. Look for this number
on the nameplate near the tower access.