Calculating 100% outside air latent loads

James Day_2

I have a customer who wants me to take 2-   5 ton air handlers and pull fresh air from outside( either 50-100 %) to pressurize and slightly dehumidify his commercial building.  I know how to calculated the sensible load of the outside air but can't remember the calculation for determining the latent load on the equipment.   Does anyone have the proper formula?

Thanks, James

Robert O'Brien

Help?

http://www.engineeringtoolbox.com/cooling-heating-equations-d_747.html

Techman

Latent load

Where is 4000cfm going once it has entered the bldg? Exhaust fans? Bringing in all of that unconditioned air puts this more  into a "make-up air" application ,than an AC application.I doubt there will be very much latent heat removal because  the "make-up air" AC evap will be operating above the dew point most of the time. Check w/ the smart folks @ CaptiveAir Co.  (exhaust/make-up air) and hear what they have to say. 

meplumber

Ditto to Techman

This is moving from AC into the realm of Make-Up Air Units. The numbers for MUA are crunched differently that for regular AC. As he said, the evap coil will be working its butt off to dehumidify the fresh air.



Captive Air is a good source, as is PowrMatic. They do makeup air/exhaust fan setups all day every day. They can probably lead you down the right path.



Let us know how you make out.

James Day_2

make up air

customer wants to pump fresh air into space to pressurize space so that it vents out through roof exhausts.  i will check out those two places.  thanks for the help i will keep you posted on it.

James Day_2

make up air

customer wants to pump fresh air into space to pressurize space so that it vents out through roof exhausts.  i will check out those two places.  thanks for the help i will keep you posted on it.

James Day_2

make up air

customer wants to pump fresh air into space to pressurize space so that it vents out through roof exhausts.  i will check out those two places.  thanks for the help i will keep you posted on it.

James Day_2

make up air

customer wants to pump fresh air into space to pressurize space so that it vents out through roof exhausts.  i will check out those two places.  thanks for the help i will keep you posted on it.

Empire_2

Q:?

What is this building being used for?  That's a lot of air to pressurize a structure.  What pos. pressure does he demand?  OR is this one of those dump a ton of air so the doors blow open......Just curious.



Mike T.