[Equest-users] Space plenums have cooling load

[Jing Hong]

 Hi Nick,

Thanks for your reply. Coz my proposed U-value is worse than the baseline,
it is normal that the baseline has a bit lower cooling load than the
proposed. However, the plenum cooling load in the baseline is way much
lower than those in the proposed, which should not be.
I figured it out. First, I realized that I should use "Plenum" instead of
"unconditioned" . But it did not change too much. Second, I duplicated the
proposed model, saved as Baseline, and then modified it with baseline
information.
After modifying the model so many times, I might mess up some physical
characteristics of the Baseline model. Starting over is easier than keeping
debugging it. Especially, for a case, you cannot find the error for hours.
Hopefully, it is useful for some of you.

Jing



On Tue, Apr 17, 2018 at 4:34 PM, Nicholas Caton <
Nicholas.Caton at schneider-electric.com> wrote:

> Hi Jing,
>
>
>
> It seems unintuitive to assert that your proposed case plenums has
> increased cooling loads – is there a good set of reasons for this?
>
>
>
> I’m also unclear on what you mean by “it still shows cooling load for
> those space” – could you unpack this a little further?
>
>
>
> Systems which use the plenums as a return air path could be a cause for
> why their loads are seen at the systems (though it sounds like you intend
> for them to be isolated).  I might start with considering the sources of
> heat gains to your plenums, and determining what *should* be happening to
> direct/indirect heat gains to plenums over time.   Should they be
> circulated back to systems responding to conditioned spaces?  Common
> sources would include indirect gains from ceiling lighting fixtures,
> envelope (skin) loads (potentially exacerbated if spandrel glass is
> present), and internal loads transferred hourly from conditioned spaces
> below and from adjacent plenums.
>
>
>
> If I had your model in-hand, I might scan for the presence of thermostat
> heating/cooling schedules being assigned to your plenum spaces, or
> assignments to a plenum space as a master zone for specific system types.
> Those could produce direct calls for airstream heating/cooling which
> otherwise wouldn’t be occurring.
>
>
>
> ~Nick
>
>
>
> *Nick Caton, P.E., BEMP*
>
>   Senior Energy Engineer
>   Regional Energy Engineering Manager
>
>   Energy and Sustainability Services
>   Schneider Electric
>
> D  913.564.6361
> M  785.410.3317
> F  913.564.6380
> E  nicholas.caton at schneider-electric.com
>
> 15200 Santa Fe Trail Drive
> <https://maps.google.com/?q=15200+Santa+Fe+Trail+Drive+%0D%0ASuite+204+%0D%0ALenexa,+KS+66219+%0D%0AUnited+States&entry=gmail&source=g>
> Suite 204
> Lenexa, KS 66219
> United States
>
>
>
>
>
> *From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] *On
> Behalf Of *Jing Hong via Equest-users
> *Sent:* Tuesday, April 17, 2018 10:43 AM
> *To:* equest-users at lists.onebuilding.org; equest-users at onebuilding.org
> *Subject:* [Equest-users] Space plenums have cooling load
>
>
>
> Hi All,
>
>
>
> I have assigned all the space plenum as unconditioned. But it still shows
> cooling load for those space, which increase the Space Cool in the report.
> The plenums in the proposed model have much higher cooling load than the
> baseline one. How could I modify it?
>
>
>
> Thank you!
>
>
>
> Jing
>
>
>
>
>
>
> ______________________________________________________________________
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>



-- 
PhD Candidate, LEED AP BD+C

School of Architecture and Urban Planning
University of Wisconsin-Milwaukee
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