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Sensible vs Latent vs Total Capacity

Sensible vs Latent vs Total Capacity

Sensible vs Latent vs Total Capacity

Hello, I'm trying to size a dedicated outdoor air unit coil and I get the following values:

Going from 100 degrees db & 63 degrees wb to 55 degrees db/wb
Total Qt = 4.5(CFM)(h2-h1) = 92,907 BTU/h
Sensible Qs = 1.1(CFM)(T2-T1) = 142,358 BTU/h
Latent Ql = 4840(CFM)(W2-W1) = -54,612

This is Utah so the air is pretty dry here which gives me a negative latent value. Which one do I use to size the split condenser unit? My guess is the sensible value but I'm not exactly sure why. Any input is appreciated. Thanks!

RE: Sensible vs Latent vs Total Capacity

Unless you are using direct evaporative cooling to contribute you want to use the sensible value. In this case your total should equal your sensible, your leaving air will be 55, but it won’t be a saturated 55/55 it will keep the dewpoint/humidity ratio of your entering air.

That negative latent number is incorrect the way you have it, a cooling coil only cools and remove moisture as a byproduct of cooling, it doesn’t add moisture in any way. In your case it’s 0 latent.

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