[Equest-users] Unmet hours BOTH htg & clg

[Pasha Korber-Gonzalez]

Hi Alex-  This is great, thank you! I appreciate your help and taking time
to review my model details.  I've been stuck on this file for a few months
now and my enthusiasm is nill, now.   Thank you 1000x

Regarding your feedback, I'll jump on your suggestions today and check
things out.

I had previously (up until yesterday) been running the AHU as VAV, but
decided to throw it over to PIU to see if that helped with anything.  I had
also been running the T-stats as Reverse Action (system default), but in
the warnings the notes suggested the proportional control so I had switched
that too-- so weird that you were able to see a reduction in the throttling
hours when you changed it.   Are you by chance running your eQuest version
is DOE 2.3 mode?  I typically haven't been running my files with 2.3, so if
you are doing this I will switch my program to see how this aids me.

I appreciate your insight on the OA ration value at the system level, so I
will make those adjustments at the zone CFM/person.  I also appreciate and
agree with what you stated in item 4 about the zone level airflows, My long
past experience also showed that eQuest doesn't properly distribute
airflows from the system level, so I will go back and adjust my inputs
properly zone by zone (of course I was being 'lazy' when I set this up and
trying to hit the target with a fast & swift approach).  Thank you for the
insight and "nudge" to do things right.  LOL

Item 6- good idea on the fan schedules... I know at some point last year I
think I had set the fan schedules to -999 operation, but I remember
changing them back to on/off scheduling when I was trying to force a
balance in the model file.

I know it sounds funny, but it is fun to receive feedback and help from our
fellow eQuest modelers, so again Thank you--- our little isolated eQuest
'islands' that we work on sometimes get so lonely and makes us crazy!  LOL
 I'll let you know how these adjustments work.

Have a great day.

Pasha Korber
ph 308-763-1593

On Wed, Jan 13, 2021 at 7:14 AM Chapin, Alex N <
Alex.Chapin at masonandhanger.com> wrote:

> Hi Pasha,
>
>
>
> The unmet load hours are coming from AHU-15. I noticed the following items
> that may help you debug the issue:
>
>
>
> 1.      The SS-R report indicates that the zone L2ComputerLabZone is
> within the 100+ part load range for 8760 hours/yr. This is causing AHU-15
> to not be able to reset its supply air temperature which means you are
> doing a lot of simultaneous heating and cooling in the other zones,
> especially at the perimeter. This could reduce unmet load hours and it will
> also reduce energy use if you put that zone on its own single zone system.
>
> 2.      You are using the Powered Induction Unit system type but have all
> of the zone terminal types set to Std VAV Terminal. You should set any
> perimeter zones to either Series or Parallel PIU terminal type. This will
> allow those zones to pull induced air from warmer core zones with the Std
> VAV Terminal terminal type. Note that if you want to keep L2ComputerLabZone
> on AHU-15, applying the correct terminal types may help also since that
> zone will have excess heat to share with other zones.
>
> 3.      You set OA ratio at the system level of 0.22 but the SV-A report
> states 0.454. If the correct value is 0.22, then you need to reduce the
> cfm/person OA input found at the zones because these will override the
> system level OA ratio.
>
> 4.      You might want to check that the supply airflow and design
> cooling supply air temperature and zone reheat delta T are sufficient for
> the loads. You are hard coding the supply airflow at the system, it might
> be helpful to set it at the zone if you know the required airflow per zone
> (I’ve found that eQUEST doesn’t do a great job at distributing airflow to
> the zones sometimes).
>
> 5.      Switching the zone thermostat type to Reverse Action from
> Proportional helps also (I did a quick test and overall unmet hours went
> from 65 to 55%).
>
> 6.      SS-O report seems to show more unmet heating hours in the
> morning, therefore it may be worth revising the fan schedule to include up
> to 6 hours of optimum start period (use a value of -999).
>
>
>
> Good luck.
>
>
>
> *Alex Chapin* PE, BEMP, LEED AP BD+C, O+M
> Energy Engineer | Mason & Hanger
> A Day & Zimmermann Company
> *O *804.521.7072
> 4880 Sadler Road, Suite 300 | Glen Allen, VA 23060
> masonandhanger.com <http://www.masonandhanger.com/>
>
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> *From:* Pasha Korber-Gonzalez [mailto:pasha.pkconsulting at gmail.com]
> *Sent:* Tuesday, January 12, 2021 3:26 PM
> *To:* eQUEST Users List <equest-users at lists.onebuilding.org>
> *Subject:* [Equest-users] Unmet hours BOTH htg & clg
>
>
>
> Hi guys/gals-- it's been a long time since I've posted, mainly because its
> been a loooong time since I've been working on energy models.
>
>
>
> My skills might be a bit rusty, but you never forget how to 'ride a bike',
> truly...
>
>
>
> I would like some help with trying to figure out why my hours out of
> throttling range are coming in like they are-- I've managed to reduce them,
> but they are not in compliance for the LEED review yet.  And I have
> virtually "peeled" back all of my design inputs in the HVAC systems
> (specifically for AHU-15) where the problems are occurring.
>
>
>
> Can any of you please help me to take a second look at my file and see if
> you can find what aspect of the inputs are pushing out my throttling
> hours?  I appreciate any insight/info/time you can provide,  The attached
> file is in a cold Michigan climate, it has a college schedule, and basic
> loads with LED lighting system, so nothing internal should be pushing the
> loads and controls out of throttling range.  I'm available to chat about
> this if any of you would like too.  Ph 308-763-1593.
>
>
>
> I've been struggling with getting the hours in range for a few months
> now... please help.  Thank you!
>
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