Modeling buildings w/ no proposed cooling; Workaround?

Jason Chenard, PE

Sr. Mechanical Engineer

Oak Point Associates

LEEDuser Basic Member

1 thumbs up

May 2, 2014

On Sept 12, 2012 there was a thread: "Proposed model, CAV system without cooling system". It references a "high temperature set point work around". Can you please direct me to further information on this subject? I have been unable to find any further discussion of it. The reply to that thread seems to suggest that in a case where the proposed CAV system (presumably DOAS or similar) has no cooling, it's somehow allowed to model the required baseline system (VAV with reheat in that poster's example, and also in our model), but then use cooling setpoints such that baseline system cooling is never activated. Is that correct? It seems a bit pointless, but if allowed it would certainly be the most logical approach for our project. Thanks.

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Marcus Sheffer

LEED Fellow

7group / Energy Opportunities

LEEDuser Expert

4454 thumbs up

Fri, 05/02/2014 - 22:41

This is a common workaround for a situation where there is no cooling system installed since there are not requirements for the temperature setting other than they are identical between the models. I agree it is somewhat pointless to model a system that does not exist and then have it not even run so our approach is to write a narrative for the reviewer explaining that we could do this work around but do not see the point and model the baseline without a cooling system. You can also use a System 9 or 10 from 90.1-2010 for areas that are heated only.

Jason Chenard, PE

Sr. Mechanical Engineer

Oak Point Associates

LEEDuser Basic Member

1 thumbs up

Sat, 05/03/2014 - 12:11

Thanks. To clarify a bit on your last point: This is an older project for which ASHRAE 90.1 2007 applies. Would you advise using the "setpoint trick" instead of changing the system so as to avoid a possible bone of contention regarding the version of the standard?

Marcus Sheffer

LEED Fellow

7group / Energy Opportunities

LEEDuser Expert

4454 thumbs up

Sat, 05/03/2014 - 23:01

LEED 2009 project following 90.1-2007 can use any of the addendum to that version and these systems were in one of the addenda. You can use a system 9 or 10 without any question.