[Equest-users] ERV and DCV

[Daniel Knapp]

The best way to do DCV in eQUEST is to do a manual calculation of the expected reduction in OA rates by looking at the fan schedule and the occupancy schedule. Keep in mind that only the “people” part of the OA rate will be reduced, whereas the “area” part will stay the same.

eQUEST’s handling of OA rates is a strange and is not well aligned with what you might expect if you are coming at it from and ASHRAE 62 perspective. I recommend avoiding the DCV capability. For example, note that zone level OA/person and OA/sq. ft. do not sum to give the total OA in that zone as you might expect. Rather eQUEST calculates both rates and picks the larger of the two rates. See the DOE2 Volume 2 Dictionary reference document for more information. The relevant entries are “OUTSIDE-AIR-FLOW”, “OA-FLOW/PER”, and “OA-FLOW/AREA”. 

All the best,
Dan

—
Daniel Knapp, PhD, PPhys, LEED® AP O+M
danielk at arborus.ca

Arborus Consulting
Energy Strategies for the Built Environment
www.arborus.ca
76 Chamberlain Avenue 
Ottawa, ON, K1S 1V9 
Phone: (613) 234-7178 ext. 113
Fax: (613) 234-0740




> On Dec 14, 2015, at 10:07 AM, beran gurtekin <beran_gc at yahoo.com> wrote:
> 
>  
> Good morning,
> 
> I am modeling a school and the system includes ERV and enthalpy economizers as well as DCV.
> What is the best way to do DCV in eQuest (step-by-step) for LEED/ASHRAE. What are the inputs at the system level and at the zone level?
> 
> For ERV, the RTU fan takes care of the whole system (there is no self-contained fan for ERV). In that case should the static pressure drop be reduced to minimum allowed?
> 
> I have zone level OA/person and OA/sq.ft. inputs no system level OA. ERV is set up as enthalpy wheel.
> 
> Thank you,
> Beran
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