[Equest-users] Energy Recovery Wheel on VAV System

[bfountain at greensim.com]

Sadly Daniel, I do not think this is quite correct.  In the current 
version of eQUEST/DOE2.2, if you add zonal exhaust the total amount of 
heat recovery does not change.  I agree that it should -- heat recovery 
should go down as zonal exhaust is increased, but eQUEST does not 
currently do this.  I was quite surprised when it was pointed out to me. 
  A quick parametric test run where zonal exhaust is added will show that 
the total heat input will not go up when it should and on the ERV report 
(in the .sim) the amount of recovered heat will not change.

If however, you set the return fan volume lower than the supply fan 
volume (on the fan -> flow parameters tab), then the heat recovery 
capacity will be reduced appropriately.


On 2016-02-01 11:42, Daniel Knapp wrote:
> 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
>> ______________________________
>> 
>> RMF Engineering
>> Reliability. Efficiency. Integrity.
>> 
>> p: 843.971.9639
>> www.rmf.com [1]
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