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Degree Day Equivalency for Humidity???

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BronYrAur

Mechanical
Nov 2, 2005
798
Is there anything in the weather history sites that would be the equivalent to "Degree Days" for humidity? I see that the sites list min, max, and avg temperatures and dew points. They also list min, max, and avg % humidity, although they do not list the corresponding temperatures. So % humidify doesn't tell me much without the relative temperature.

Where I am going with this is that that I am trying to quantify the amount of cooling coil condensate that will be produced. I am involved with a building that has a recovery system that was never used. There will be a cost to get the system up an running, so I am trying to quantify the gain.

The total latent load of all my coils comes to roughly 40 GPM of condensate. That's a "design condition" number, so I am trying to make a calculation of how much I can expect to recover during the overall cooling season. I need to be able to tie in the local (Chicago) humidity data for the non-design conditions.

I could use the daily avg temp and avg dew point to obtain an OA condition and a latent load, but how accurate will that be? Something like a "degree day" for latent loads would make life easier.

Any thoughts?
 
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For this sort of calculation I use TMY3 data which is available for download from some programs. This data set contains 8760 data points, each one being the average conditions for a specific hour over a (I think) 15 year period.
In my office we get this data from our psychrometric chart program (hands down software) but I believe other programs such as IES also can be used to source this information.
 
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