[Equest-users] Energy Recovery Wheel on VAV System

[Daniel Knapp]

Zone exhaust is presumed to exhaust directly to the outside without going back to the system, i.e. it is assumed that you are specifying a separate zonal exhaust fan that is not connected to the main VAV system. If you remove the zone exhaust, the system level exhaust will be determined by the outdoor air fraction of the supply air. This outdoor air fraction will depend on the demand for outdoor air from the zones. i.e. the outdoor air is specified at the zone level, and determines the outdoor air supply at the system level. 

Hope that helps,
Dan

—
Daniel Knapp PhD, P Phys, LEED AP O+M
danielk at arborus.ca

Energy Efficiency Expert
Arborus Consulting
76 Chamberlain Ave
Ottawa ON K1S 1V9
(613) 234-7178
—
Daniel Knapp PhD, P Phys, LEED AP O+M
danielk at arborus.ca

Energy Efficiency Expert
Arborus Consulting
76 Chamberlain Ave
Ottawa ON K1S 1V9
(613) 234-7178

> On Feb 1, 2016, at 11:28 AM, Miles H. Martschink <miles.martschink at rmf.com> wrote:
> 
> Hello All,
>  
> I am trying to model an enthalpy energy recovery wheel on a VAV air handler serving multiple zones, and I cannot seem to get any exhaust air to pass through the wheel. I have specified the design exhaust loads at the Zonal Level and I have also setup the wheel control sequence using values that others on this forum have posted:
> ·        Operation = OA Exhaust DT
> o   DT = 5 degree F
> ·        Operating Mode = OA Heat/Cool
> ·        Make up Air Temp Cntrl = Mixed Air Reset
> ·        Capacity Control = Bypass OA
> Whenever I run the model I get an error stating, “Energy Recovery ventilator: S1 Sys (VAVS) has an exhaust flow 50% of the supply flow. Performance may be compromised. OA & Exhaust: 7313. 0.” The total sum of all the Zonal Exhaust Loads in 5505 CFM, and none of this is making it to the wheel. Does anyone have any insight as to what I might be doing wrong here? My end goal is to have the wheel modulate the return airflow in order to match the Outside Air CFM demand by the VAV system. Any input is greatly appreciated. 
>  
> Thanks,
>  
> Miles Martschink, Jr
> Mechanical Design Engineer
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