[Equest-users] HHW reset controls in eQuest

Dominique Michaud dominique at scengineers.net
Tue Sep 17 13:26:20 PDT 2013


Thank you very much for your input, Ante. I hope you don't mind that I'm
sharing your explanation with the group.

 

Your suggestions were all hypotheses that I was contemplating, and you've
validated them with your clear explanation.

 

Due to time constraints I was asked to cut corners on zoning. And as you've
alluded, I think I'm paying for it now. Since the reset savings will result
when there is a large diversity in zone thermal needs, by not modeling them
the building doesn't act like it might in reality. Modeling one zone per VAV
system will not get me very far.

 

I didn't quite have a specific energy savings number in mind; I just wanted
a positive number that I could start working with. But now that I can
conclude that my model lacks some precision, I know where to start
troubleshooting.

 

Thank you again,

 

Dominique Michaud | Project Engineer

 <http://www.scengineers.net/> SC Engineers, Inc. 

 
<http://maps.google.com/maps?hl=en&cp=40&gs_id=2&xhr=t&q=17075+Via+Del+Campo
,+San+Diego,+CA+92127&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1280&bih=583
&wrapid=tljp132371020953200&um=1&ie=UTF-8&hq=&hnear=0x80dbf72707811bcf:0xafd
a74b7e473e651,17075+Via+Del+C> 17075 Via Del Campo, San Diego, CA 92127

P: 858.946.0333 | C: 858.436.4213 |F: 858.946.0334

 <mailto:dominique at scengineers.net> dominique at scengineers.net |
<http://www.scengineers.net/> www.scengineers.net

 

 

 

 

 

From: Ante Vulin [mailto:avulin at yrgxyz.com] 
Sent: Tuesday, September 17, 2013 10:39 AM
To: Dominique Michaud
Subject: Re: [Equest-users] HHW reset controls in eQuest

 

Hi Dominique,

 

  You hooked my curiosity.  What kind of savings were you expecting? A few
things jump out at me. Your boiler may be causing some problems. The
efficiency of the boiler will decrease at part-load, and if you are reducing
the load on the boiler, you may see gas consumption increase.  Modeling with
one boiler if the building will have multiple boilers will exacerbate this
problem.  Also, the zoning of your model may be throwing off your results.
You have it set up with a separate HVAC system for every zones, and the
zones themselves are very large. You could be minimizing your heating load
by combining zones with different exposures and therefore limiting your
potential savings. With control strategies like resets, it pays to make sure
the model is as close to real conditions as possible.   There's also a
chance that you don't have many opportunities to reset your heating hot
water -- if the building tends to only need heating when OA temps are low,
then your reset hours are limited. You could probably check this by looking
at the space loads for your building based through the hourly reports.

 

Good luck with this issue,

 

Ante




________________________________________________

 

Ante Vulin  Sustainability Manager

LEED AP BD+C

 

YR&G 

sustainability consulting, education and analysis

161 Bowery - 4th Floor - NY NY 10002

D 917.602.1985

yrgxyz.com <http://yrgxyz.com/>  | facebook
<https://www.facebook.com/pages/YRG/273046436043564?sk=wall>  | twitter
<http://twitter.com/#!/YRGxyz> 

 

 

On Tue, Sep 17, 2013 at 12:51 PM, Dominique Michaud
<dominique at scengineers.net> wrote:

Fellow eQuest modelers,

 

I'm reposting my last query (see below) with an example of one of the eQuest
models that I have been having trouble with. Again, I'm having trouble
modeling some very simple (IMO) heating hot water/boiler energy efficiency
measures. I'm just not seeing the amount of savings I'm expecting. I'm even
seeing negative savings for some measures (this is especially frustrating).

 

My offer of a beer to anyone who helps me solve my problem still stands,
though I'll have to restrict my offer to US/Canada destinations. Did I
mention I'm in San Diego
<http://travel.nytimes.com/2012/05/27/travel/san-diegos-thriving-craft-beer-
scene.html?pagewanted=all&_r=0> ?

 

Thanks in advance for your help.

 

Dominique Michaud | Project Engineer

 <http://www.scengineers.net/> SC Engineers, Inc. 

 
<http://maps.google.com/maps?hl=en&cp=40&gs_id=2&xhr=t&q=17075+Via+Del+Campo
,+San+Diego,+CA+92127&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1280&bih=583
&wrapid=tljp132371020953200&um=1&ie=UTF-8&hq=&hnear=0x80dbf72707811bcf:0xafd
a74b7e473e651,17075+Via+Del+C> 17075 Via Del Campo, San Diego, CA 92127

P: 858.946.0333 | C: 858.436.4213 |F: 858.946.0334

 <mailto:dominique at scengineers.net> dominique at scengineers.net |
<http://www.scengineers.net/> www.scengineers.net

 

 

 

From: Dominique Michaud [mailto:dominique at scengineers.net] 
Sent: Friday, September 13, 2013 5:35 PM
To: 'equest-users at lists.onebuilding.org'
Subject: HHW reset controls in eQuest

 

Fellow eQuest modelers, 

 

I am experiencing a great deal of grief trying to model HHW/boiler energy
efficiency measures using eQuest. I am trying to model HHW temperature
resets based on outside air temperature and boiler lockout strategies.

 

Under the DD Wizard, "Hot Water System Control and Schedule > Setpoint is:"
drop-down list I've selected "OA Reset" and allowed the resulting hi/low
temperature values to default, namely HW Max Temp: 180.0F and HW Min Temp:
140.0F (see attached screenshot).

 

Digging into the BDL, I noticed this issue:

 

     *5356 * "B5HW Lp Heat Reset Sch-D" = DAY-SCHEDULE-PD

     *5357 *    TYPE             = RESET-TEMP

     *5358 *    SUPPLY-LO        = 140

-CAUTION-------------------------- ===
-------------------------------------------------------

-CAUTION--- VALUE GREATER THAN MAXIMUM OF 0.1200E+03

     *5359 *    SUPPLY-HI        = 180

-CAUTION-------------------------- ===
-------------------------------------------------------

-CAUTION--- VALUE GREATER THAN MAXIMUM OF 0.1200E+03

     *5360 *    OUTSIDE-LO       = 30

     *5361 *    OUTSIDE-HI       = 65

     *5362 *    ..

 

However, it looks as though the values are accepted for the reset schedule:

 

-NOTE- - -         DATA FOR     B5HW Lp Heat Reset Sch-D

-INPUT - - - - - - - - - - - - - - - - - - - - - - - -  TYPE             =
RESET-TEMP

-INPUT - -                                              OUTSIDE-HI       =
65.0000 F

-INPUT - -                                              OUTSIDE-LO       =
30.0000 F

-INPUT - -                                              SUPPLY-HI        =
180.0000 F

-INPUT - -                                              SUPPLY-LO        =
140.0000 F

-DEFAULT - - - - - - - - - - - - - - - - - - - - - - -  DAY-HOURS        =
1.0000

-DEFAULT -                                              DAY-HOURS        =
24.0000

 

 

When I run the model I end up negative natural gas savings (i.e. more gas
usage than in my baseline case). No matter what dials I try to turn with
this EE measure, I consistently end up with negative savings. Even more
frustrating, when I try to run a OA temperature lockout for the boiler, I
get even more energy use than my baseline model!

 

Can anyone provide me with some guidance on what I need to do to get my
model to run these EEMs correctly? Help put me on the path to solving these
problems and I will buy you a beer.

 

(Note: I am using eQuest 3.64 Build 7130 - the latest release)

 

Thank you for any assistance you can provide.

 

Yours,

 

Dominique Michaud | Project Engineer

 <http://www.scengineers.net/> SC Engineers, Inc. 

 
<http://maps.google.com/maps?hl=en&cp=40&gs_id=2&xhr=t&q=17075+Via+Del+Campo
,+San+Diego,+CA+92127&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1280&bih=583
&wrapid=tljp132371020953200&um=1&ie=UTF-8&hq=&hnear=0x80dbf72707811bcf:0xafd
a74b7e473e651,17075+Via+Del+C> 17075 Via Del Campo, San Diego, CA 92127

P: 858.946.0333 | C: 858.436.4213 |F: 858.946.0334

 <mailto:dominique at scengineers.net> dominique at scengineers.net |
<http://www.scengineers.net/> www.scengineers.net

 


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