[Equest-users] Demand Controlled Ventilation and EA Credit 1

[Karen Walkerman]

All,

below is a draft letter to the EA Credit 1 TAG chair.  I welcome any edits,
or critiques, and if anyone would like to be a co-signer of the letter,
please let me know.

Thanks,

--
Karen


It has come to our attention from a posting on the eQuest list-serve that a
fellow energy-modeling professional has been asked to model proposed design
and baseline design ventilation rates differently where the proposed design
model utilizes demand controlled ventilation.  We have searched the ASHRAE
90.1 documentation as well as the LEED reference documentation and
consistently find the requirement that baseline ventilation rates be modeled
the same as the proposed design, and that credit can be taken for demand
controlled ventilation.

We understand that large energy savings can be gained from demand controlled
ventilation and that in certain cases, 'gaming' of the system could result
in abnormally high ventilation rates for the baseline design, while the DCV
system keeps ventilation rates low in the proposed design, however, our main
concern is that energy modelers are being made aware of changes to
guidelines during the design review process.  At this stage, the energy
modeler has already completed a significant amount of work in preparing the
proposed and baseline design energy models, and all associated
documentation.  Changing the baseline design ventilation rates requires
re-modeling of the building and increases the likelihood that the project
will have to challenge a 'rejected' result if the LEED reviewer is not
satisfied with the energy modeler's response and modeling changes.

We feel that it may be time to develop modeling guidelines for demand
controlled ventilation, and that these guidelines should be developed,
released, and required in a similar fashion to the district energy
guidelines published by LEED for NC 2.2  Furthermore, we feel that any
changes made to EA Credit 1 energy modeling guidelines should be made with
adequate notice to the energy modeling community.

Thank you for your consideration on this issue,

--
Karen Walkerman
Second Law
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