Hello all,
is it true that "Whenever credit is taken for demand control ventilation in the Proposed Case, the outside air ventilation rates for the Baseline Case must be modeled using minimum ASHRAE 62.1-2007 rates"?
It sounds strange because for achieving the DCV credit we have to demonstrate the increase of the outside air (according to Italian standard, outside flowrate is 30% bigger than the 62.1 minimum outdoor flowrate).
So how could it be positive for IEQp1 and negative for EAp2?
Thank you a lot
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 19, 2012 - 12:07 pm
Yes It is true. To be clear - Whenever credit is taken for demand control ventilation in the Proposed Case, the outside air ventilation rates for the Baseline Case must be modeled using minimum ASHRAE 62.1-2007 rates from the Proposed Case. Basically the OA rate must be identical in both models.
Often there is a trade-off between bringing in more outside air (positive benefits to the occupant who get more fresh air) and having to expend more energy to condition that air. So yes there will be less energy savings associated with DCV in this case. LEED is full of such trade-offs.
I would put the blame for this conundrum clearly on the unreasonable Italian standard! :-)
FABIO VIERO
Head of SustainabilityManens S.p.A.
18 thumbs up
October 23, 2012 - 7:57 am
Thank you Marcus,
very last question: how can i modify the Proposed Building outdoor schedule due to DCV? Is it a matter of reasonable evaluations or there are some guidelines?
Thank you very much!
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 23, 2012 - 10:21 am
We basically tie the outdoor air rate to the occupancy schedule.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 23, 2012 - 3:49 pm
Fabio,
We may have found a way around your situation. You can apply addenda to 90.1-2007. Addendum da might help - The intent of this addendum is to establish that an Appendix G baseline shall be based on the minimum ventilation requirements required by local codes or a rating authority and not the proposed design ventilation rates.
http://www.ashrae.org/standards-research--technology/standards-addenda/A...
So if you apply this addendum the problem may disappear. If it works for you I expect you to call me the magic man moving forward. :-)
FABIO VIERO
Head of SustainabilityManens S.p.A.
18 thumbs up
October 24, 2012 - 9:27 am
Thank you very much magic man!
I guess now we need to assess the impact of using this addenda on IEQc3.
Ciao e grazie!
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 24, 2012 - 10:44 am
If you mean the impact on EQp1 and EQc2 there will not be any. You would still use your local requirements for EQp1 and ASHRAE 62 to evaluate EQc2. Both of these are already required.