[Equest-users] [eQuest-users] Transformers in Energy Model

Nick Caton ncaton at smithboucher.com
Mon Aug 16 14:53:34 PDT 2010


First, thanks to Jason for the heads up!  Taking credit for premium
efficiency transformers is a pretty novel idea in my circles.

 

I'm re-directing this response/discussion to eQuest-users as I'm
applying this in eQuest and have found a snag along the way...

 

After coming up with and creating a custom TRANS-LOSS-FPLR curve using
manufacturer data, I hop over to create a new meter to assign this to.
The default transformer size field starts off blank, as transformer
losses are not normally modeled.  After entering the transformer size
(225kVA) on the first screen, I immediately encounter the following
dialog:

 

 

[text includes:  "Range Checking Violation: Value must be > 1"]

 

Hmm.  This seems odd... the text files for TRANSFORMER-LOSS and
TRANS-LOSS-FPLR both indicate this value should be a fraction of the
Transformer size representing the maximum loss (therefore < 1).  In my
example, the 225kVA transformer has a maximum loss (at full load) of
3,898VA, so I was expecting TRANSFOMER-LOSS should be 3898/225000 =
0.01732.  Regardless, I haven't entered anything in that field yet... so
clicking Cancel to proceed, I return to the following:

 

 

 

Hmm.

 

The error appears to result from the "Loss:" field being unpopulated.  I
cannot however input the Loss ratio (clouded "n/a") for the custom curve
to be applied against!  The field ignores anything I type when
highlighted...  

 

Okay so saving and exiting, I navigate the .inp to add TRANSFORMER-LOSS
there:  

 

"Step Down Meter" = ELEC-METER      

   TYPE             = BUILDING

   TRANSFORMER-SIZE = 225

   TRANSFORMER-LOSS = .01732

   TRANS-LOSS-FPLR  = "Custom Xfrmr fPLR"

   ..

 

Starting eQuest back up, the following error is generated in BDL -
(eQuest proceeds to open and overwrite .01732 with a zero):

 

     *13249* "Step Down Meter" = ELEC-METER

     *13250*    TYPE             = BUILDING

     *13251*    TRANSFORMER-SIZE = 225

     *13252*    TRANSFORMER-LOSS = .01732

*ERROR**************************** ======
****************************************************

*ERROR*****VALUE NOT BETWEEN 1.0000 AND 1.5000

     *13253*    TRANS-LOSS-FPLR  = "Custom Xfrmr fPLR"

 

Here's where I throw up my hands!  What interpretation of
TRANSFORMER-LOSS results in a value that would always fall between 1.0
and 1.5?

 

On a related note:  I've read through all the help files regarding
electrical meters (I think)...  Once this is meter up and running, can
anyone suggest any method for applying a specific subset of electric
loads (say, only plug loads) to this new meter with the transformer
losses defined?  

 

~Nick

 

 

 

NICK CATON, E.I.T.

PROJECT ENGINEER

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

Check out our new web-site @ www.smithboucher.com 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Sami,
Vikram
Sent: Wednesday, August 11, 2010 4:00 PM
To: Sami, Vikram; Jason Boehning; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Transformers in Energy Model

 

I should have mentioned I was referring to eQUEST...

 

Vikram Sami, LEED AP

Sustainable Design Analyst

1382 Peachtree St. NE, Atlanta, GA 30309

t: 404-443-7462    f: 404.892.5823       e: vikram.sami at perkinswill.com
www.perkinswill.com <http://www.perkinswill.com/> 

Perkins+Will.  Ideas + buildings that honor the broader goals of society

 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Sami,
Vikram
Sent: Wednesday, August 11, 2010 4:31 PM
To: Jason Boehning; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Transformers in Energy Model

 

You can model transformer sizes and losses in the detailed edit mode
when you open up you electric meter.

 

I have to confess I have not modeled a transformer in a model yet (the
default is not to model a transformer and the loss associated). You can
specify a loss part load curve too:

 

TRANS-LOSS-FPLR

Takes the U-name of a curve that gives the multiplier on
TRANSFORMER-LOSS as a function of the part load ratio (current hour load
on the meter divided by TRANSFORMER-SIZE). The transformer loss is
calculated hourly as

          (TRANSFORMER-SIZE) x (TRANSFORMER-LOSS) x (TRANS-LOSS-FPLR
value)

The load is the sum of that due to all directly connected equipment and,
for TYPE = UTILITY and BUILDING, other ELEC-METERs. The default curve is
linear from 0.1 at zero load to 1.0 at full load.

 

Like I said I haven't done it yet - good luck. Let me know how it turns
out

 

Vikram Sami, LEED AP

Sustainable Design Analyst

1382 Peachtree St. NE, Atlanta, GA 30309

t: 404-443-7462    f: 404.892.5823       e: vikram.sami at perkinswill.com
www.perkinswill.com <http://www.perkinswill.com/> 

Perkins+Will.  Ideas + buildings that honor the broader goals of society

 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Jason
Boehning
Sent: Wednesday, August 11, 2010 4:14 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Transformers in Energy Model

 

I am new to energy modeling and I am curious if there is a way to take
credit for more efficient transformers in an energy model. Some of our
transformer reps have said that there is not a LEED credit for more
efficient transformers, but you have to gain the credit through the
energy model. Would it just be through more heat in a space? I
appreciate any information I can get in this matter. 

 

Best Regards,

 

Jason Boehning, EIT

Mechanical Engineer

 

6161 Savoy, Suite 1212

Houston, Texas  77036

 

 v.  713.482.2322

 f.   713.482.2314

 e. Jason.Boehning at ricegardner.com
<mailto:Jason.Boehning at ricegardner.com> 

 


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