View Full Version : Make-up Air unit vs. chiller performance
12-22-2010, 11:07 AM
Help me with this thought. We currently have a 12,800cfm MAU that just brings in outside air without ac or heat. We are looking to replace this unit. My thought is that if we purchase a MAU that conditions the OA (especially in the summer time - TN area), we can do the following: raise the chilled water temperature (currently 46-50deg), to reduce chiller running time there by saving money. Also since I'm bringing in unconditioned air with the current unit, the chiller will not have to work as hard for dehumidification purposes. Tell me what you think, and suggested research literature.
12-22-2010, 12:33 PM
yep. best to condition the outside air or temper it as in most cases. Here in Texas we do it mostly for summer. 110 degree out side air is a killer. We use Aaons and a couple other manufactures for heat wheels to temper the air and then reverse for winter. In some buildings we just taped of the chiller and placed a small water coil in it for summer use and then a hot water coil for winter. Doesnt have to be to complecated. But it does make a difference, especialy high outside humidity.
12-23-2010, 08:46 PM
If you let your Chilled water return temperature get above 53 F, you can pretty much guarantee you'll grow mold.
12-24-2010, 11:27 AM
you can look at a neutral air unit such as a munters, which utilizes wheel or wheels to condition the air, along with dx or chilled water and a dx system for regenration. the dx cools the supply air, and the condenser air off the dx regenrates the wheel, utilizing the waste heat. you could use say the chilled water for cooling, and the wheels for dehulidification along with the dx. expensive first cost system, but energy efficient. this is a semi cutom unit which can be suited to your application via the local rep.
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