AC vs Dehumidify


  #1  
Old 01-31-08, 10:58 PM
Z
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AC vs Dehumidify

I need help with a sanity check here guys....

So with central a/c all things being equal... a slow blower speed will yield lower RH higher temp and fast blower will yield higher RH lower temp ???
 
  #2  
Old 01-31-08, 11:26 PM
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Not necessarily.

Dehumidification comes about by lowering the air temperature to below the dew point at which the water vapor condenses on the cooling coil and trickles down the drain. By running the blower at a lower speed it allows the air to be in contact with the cooling coil for a bit longer time period and THAT allows for more cooling of the air per unit of volume allowing more water vapor to condense.

Running the blower at a higher speed may under some conditions allow the condensed water to re-evaporate into the air stream thereby effecting a lesser amount of dehumidification.

In practice, especially in residential units, all things considered the lower blower speeds will allow more dehumidification with less cooling of the ENTIRE volume of air in the home. With this lesser amount of cooling the unit will run for a longer period of time (because residential A/C operates under temperature control) and it is this overall process that gives better dehumidification with a lower blower speed.
 
  #3  
Old 02-01-08, 06:06 PM
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OK - got it now. Thanks for clearing that up....
 
  #4  
Old 02-02-08, 07:34 AM
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Now if only someone could explain it to me.
 
 

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