Hot water coil in main vav air handler?
Hot water coil in main vav air handler?
(OP)
I'm reviewing a design done by an outside engineer for a new 2 story office building. The engineer has specified a vav w/ reheat system. The main cooling cfm is 30,000 and heating cfm is 15,000. The OA% is high enough that on the coldest day the mixed temp is 40 degrees. The engineer specified an additional heating coil in the ahu itself, which is understandable, but he specified the LAT from the hw coil to be 82 degrees, instead of 55 degrees. I can't think of a reason for this, but i'm sure there is a logical explanation. the reheat terminals are hw and sized for 55-90 degree F. Any ideas?





RE: Hot water coil in main vav air handler?
RE: Hot water coil in main vav air handler?
RE: Hot water coil in main vav air handler?
Is there a chance the system would go to 100% outdoor air? If so, the 'oversized' coil could be intended to bring the air from outdoor temp to 55 deg F.
Or... could be a misprint.
RE: Hot water coil in main vav air handler?
Otherwise, the designer is guilty of oversizing, which I see too much of in my own office.
Morning warmup should not need the OA, so a coil capable of 40-82 will only need to heat 60 (worst case return air temp) to 70 or 80 or whatever the warm up sequence calls for.
RE: Hot water coil in main vav air handler?
RE: Hot water coil in main vav air handler?