View Full Version : a/c in a make up air plenum?
06-14-2011, 09:17 PM
I was just thinking, if you had an area that a make up air unit was servicing that was way to hot, is there any reason that putting an air conditioner in the plenum of the make up air is a bad idea?
I would suspect you would get your 20 degree drop in temperature across the coil, which would help keep the area cooler
06-14-2011, 09:54 PM
i have seen make-up air units with cooling coils built into the ductwork. however the area the make-up air is serving should already have a way of conditioning the air. My point is you may have a problem elsewere if the design of the space included fresh air in the calculations.
06-14-2011, 10:08 PM
I've seen MAU's with DX cooling. Needs to be properly designed to work right.
06-14-2011, 10:57 PM
If its food service be careful, gotta get everthing sized correctly, its a design issue.
06-16-2011, 04:56 PM
Chilled water or condenser water available? I've seen both used. Chilled water obviously for cooling only, and condenser water from a WSHP building to temper OA for make up/ fresh air
06-16-2011, 07:55 PM
if you can give me a maufacturer name on the mau, i might be able to tell you more. there are systems called heat recovery ventilators that have a heat wheel, which pulls x amount of air out of the space and the same amount of outside air and transfers the temp of the building air to the fresh air. You may have a loose belt,clogged filters, or a clogged heat wheel. in any event there is usually fresh air into the space and way to pull the same amount out of the space.
06-16-2011, 08:55 PM
Depending on the psychrometrics , a direct or indirect evaporative cooler will be more cost effective to operate. We do alot of work with Reznor. You can use their Preeva with a evaporative cooling module or if you really want to get fancy check out their MAPs units. The Maps have dx or chilled water coils.
06-16-2011, 09:24 PM
That is what we have at correctional facilities. 100% outside air is being conditioned. It has to be size properly to work.
duke of earl
06-19-2011, 09:57 PM
I'm with sometech, install a heatwheel.
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