Is there anyway to calculate the condensate generated in a chilled water coil?

Question

Is there anyway to calculate the condensate generated in a chilled water coil?

Answer 1

I must differ with an answer.

Cooling the air to saturation will maximixe its relative humidity; it will not remove any moisture. The air must be cooled to below saturation, that is, to below its entering dew point , before water will begin to be condensed.

Using the Psych chart, plot the entering and leaving conditions. Then note the change in absolute humidity on the right -hand scale. This will be in grains or else in pounds of water per pound of dry air. Multiply by the pounds of air per minute. [ Very small water contents are often expressed in grains( 1/7000 lb) to simplify the math.] Standard air has a density of 0.075 lb/ cu ft.

You will get pounds of water per minute.

As an aside - - regardless of some texts, the average air volume will actually begin to dehumidify at about 70% RH and leave the coil at about 95% RH at the depressed dew point temperature. This is because some of the air never contacts to cooling fins.

Answer 2

If you have a psychometric chart handy, moving the process from a starting condition to saturation will yield the difference in grains of moisture. Then convert.

e.g. 100 CFM of air at .....condition passes over a coil at ......deg F. The difference in grains of water is converted to the volume under consideration, and the amount of moisture is found per min.