[Equest-users] Ashrae Baseline Model & Unmet loads

[Pasha Korber-Gonzalez]

sometimes unmet load hours are logged during the morning start-up warm-up
periods.  What's happening is that for every zone (at every hour) the
program is trying to meet the loads with in a 60 minute (1 hour) approach.
If you have a building that has intense internal loads occuring right at the
hour of start-up or warm-up operations it will take more than 60 minutes to
get that space fully conditioned, so now you have 1 hour (per zone) logged
as "hours unmet."

I don't have the chance now to look at your sim file, but maybe set your
start-up schedules to give a 2 or 3 hour building warm-up cycle and see if
that helps your unmet loads.

that's my quick thought/2-cents.

pkg

On Wed, Jul 21, 2010 at 11:30 AM, Martz, Amanda <amartz at klingstubbins.com>wrote:

>  I have reverse action set, a range of 6 degrees, night cycling set to
> “cycle on any,” and a 20 degree delta T. You’re right, those usually do the
> trick, that’s why I’m so stumped.
>
>
>  ------------------------------
>
> *From:* Amber Welsh [mailto:amber at timmonsdesigneng.com]
> *Sent:* Wednesday, July 21, 2010 1:28 PM
> *To:* Martz, Amanda
> *Subject:* RE: [Equest-users] Ashrae Baseline Model & Unmet loads
>
>
>
> Amanda,
>
>
>
> When I first had these problems it had to do with fan control and night
> cycling.  Make sure that your fans are cycling.  Next, check to make sure
> that you have a minimum delta T of 20 between room set point and supply air
> temperature.  These are the 2 biggest things affecting the unmet hours.
>
>
>
> Amber
>
>
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Martz, Amanda
> *Sent:* Wednesday, July 21, 2010 1:22 PM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] Ashrae Baseline Model & Unmet loads
>
>
>
> I have several VAV units with reheat serving several zones in my Ashrae
> baseline model. It is autosizing all of the capacities, so why would I have
> unmet loads? I have cooling and heating set to size at 1.15 and 1.25 as
> Ashrae states, and I have cooling control set to “warmest.” I’m sure it is a
> control issue, but I can’t figure out what exactly it is. I attached my
> model, any help would be very greatly appreciated!
>
>
>
> Amanda E. Martz, EIT, LEED AP
>
> Mechanical Engineer
>
> KlingStubbins
>
> 2301 Chestnut Street
> Philadelphia, Pennsylvania
> 19103
>
> P 215.569.2900, ext. 3612
>
> F 215.569.5963
> E amartz at klingstubbins.com
> W www.klingstubbins.com
>
>
>
>
>
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