Elementary humidity question

[siliconwafer]

I have what is probably a very simple question for most of you guys but it was not clear to me. I know that from the Psych chart that if I have a LAT control on the coil that I should be able to determine the RH when I reheat it to 68 degrees F. My question is "does the Entering Chilled water temperature affect the RH of the air leaving the cooling coil if I keep the coil LAT the same?"I know that with colder chilled water temps the cooling water control valve will not be open as far as with a warmer chilled water temp but can it actually change the RH of the air leaving the cooling coil if I have that temp set? I hope that this question makes sense.Thanks for bearing with me on this one!

 

[willard3]

Trace the wet-bulb line on the chart.....if cw temp changes, dry bulb temp will decrease, if dry bulb decreases, wet bulb decreases.

 

[imok2]

If the lat remains constant nothing will change EX if you lower the chill water temp from 45*F to say 42*F and the control valve can still maintain a constant LAT the RH should stay constant

 

[siliconwafer]

Thanks for your replies. I wasn't sure if since some the air saw a lower EWT that you would get more dehumidification than you would normally expect from the the Psych chart given an constant 55 degree F leaving air temp. I appreicate your time to answer the question.

 

[walkes]

You can reduce the RH by reducing the cooling coil leaving air temp. If you have a coil that can have a LAT of 50°F instead of 55°F then reheat to 68°F then you will have a lower RH. If the cooling coil LAT is 55°F no matter what the chilled water temp. then nothing changes.

I think that is what you are asking.