[Equest-users] Modeling of indirectly conditioned spaces under ASHRAE 90.1-2007 AppG

Nicholas Caton ncaton at catonenergy.com
Sat Aug 22 08:35:11 PDT 2015

Hi Frédéric!

1.       In the future you can more simply remove the calls for
heating/cooling by removing the cooling and heating thermostat schedules
entirely (right-click and restore default from the interface).

2.       Per Appendix G the Baseline should match the Proposed case
thermostat schedule setpoints (or lack thereof) for each zone, so you are
in the clear on that front if you’ve carried the “extreme” temperature
setpoints over.

3.       I think you have the leeway to consider a series of spaces to be a
single “zone” for simplification and application of Appendix G guidance.  I
might assign all your corridor zones (in the model) to a single baseline
system and continue to designate only the top floor as your control zone
(with all other zones having no heating/cooling thermostat schedules, or
else modified to the extremes as you’ve done).

4.       If after LEED review it is determined you must add “dead” systems
to the zones which won’t be calling for heating/cooling, rest assured there
should be zero impact on your results ;)



*Caton Energy Consulting*
  306 N Ferrel

  Olathe, KS  66061

  office:  785.410.3317


*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] *On
Behalf Of *Frédéric Genest, ing.
*Sent:* Friday, August 21, 2015 5:12 PM
*To:* equest-users at lists.onebuilding.org
*Subject:* [Equest-users] Modeling of indirectly conditioned spaces under
ASHRAE 90.1-2007 AppG

Greetings esteemed group.

I'm in the process on modeling an hotel project for LEED compliance.

If I read AppG correctly,  all "hotel-type" thermal zones are modelled as
System 1 or or 2, one system per zone. The exceptions don't apply here (I

There is a dedicated outdoor air system supplying OA air to the guest
rooms,  corridors  and a bunch of other spaces.

My problem is the following: the top floor corridor is the only location
with a thermostat used to control the OA supply temperature  (to maintain
that corridor between its heating  and cooling setpoints). The temperatures
of all other thermal zones are basically uncontrolled (except perimeter
zones which have baseboards,  which are thus controlled locally).

As such, to avoid generating unmet load hours,  I've set the temperature
shedules to 199F in cooling and 0F in heating. The resulting temperatures
are satisfactory and not that far from the controlled one on the top floor.

However, the baseline building will now have thermal zones with PTACs and
setpoints that will basically prevent those from operating.

Any word of advice on this issue would be welcome.


Frédéric Genest, ing. M.Sc.A.



fgenest_ing at bell.net

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