[Equest-users] LEED Issue with EQuest Software's Ability to Model Boilers on Ground Loops

[Kathryn Kerns]

Thanks so much for trying this out. I was looking at it last night and
realized the same thing. What we really need is to have the ground loop
primary, the boiler secondary, and activate the boiler when the loop
drops below a temperature or maybe when the ground loop HX exceeds its
ability to provide heat. Thanks again.

 

 

 

Kathryn Kerns

Systems Specialist

BCE Engineers, Inc.

| Ph: 253.922.0446 | Fx: 253.922.0896 | 

 

 

________________________________

From: Matthew W. Higgins [mailto:MWHiggins at bpce.com] 
Sent: Friday, August 16, 2013 8:56 AM
To: Kathryn Kerns; Steve Woolery; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] LEED Issue with EQuest Software's Ability to
Model Boilers on Ground Loops

 

Bill found some issues in the PS-H with this methodology (Thanks Bill!).
I'm going to look at it again and may be able to provide some more
feedback. I should have noted that the availability schedules don't get
around your problem, they just allow for that equipment to be on the
loop and unused/sparingly-used.

 

MATTHEW HIGGINS

CEM, ASHRAE-HBDP, LEED-AP (BD+C) 

 

Bridgers & Paxton Consulting Engineers, Inc.

4600-C Montgomery Blvd. NE

Albuquerque, NM  87109

 

505.883.4111  (t)    505.888.1436  (f)

 

 

 

From: Matthew W. Higgins 
Sent: Thursday, August 15, 2013 4:10 PM
To: 'Kathryn Kerns'; Steve Woolery; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] LEED Issue with EQuest Software's Ability to
Model Boilers on Ground Loops

 

Hi I recently went thru this too.

 

If you go through the usual steps to create a GCHP loop, do these steps
next:

 

-          Create a hot water loop (and leave it as primary)

-          Go back to the GCHP loop and call it secondary

-          After doing so close out of that loop and go back into it and
indicate that the primary loop is the HW loop 

-          Create a boiler and put it on the HW loop

-          After this you have 2 options:

1)      Use equipment controls/load management and flag schedules to
allow one loop to be on and the other off seasonally as you see
necessary

2)      Create an availability schedule in the loop's control tab for
the HW loop to suggest a high degree of diversity or off seasonally as
mentioned

 

I prefer step 2 above and I know there are some issues when you don't
have a tower, like below, but I've made it work previously.

 

 

 

MATTHEW HIGGINS

CEM, ASHRAE-HBDP, LEED-AP (BD+C) 

 

Bridgers & Paxton Consulting Engineers, Inc.

4600-C Montgomery Blvd. NE

Albuquerque, NM  87109

 

505.883.4111  (t)    505.888.1436  (f)

 

 

 

From: equest-users-bounces at lists.onebuilding.org [
mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Kathryn
Kerns
Sent: Thursday, August 15, 2013 10:27 AM
To: Steve Woolery; equest-users at lists.onebuilding.org
Subject: [Equest-users] LEED Issue with EQuest Software's Ability to
Model Boilers on Ground Loops

 

Everyone, I have received a snarky comment from the LEED reviewers
regarding eQuest and not being able to model back-up boilers on a ground
heat pump loop. See below. The ground loop is large enough not to
generate any temperature low alarm messages, the ground loop pump flow
never reaches 100% flow except for 1 hour and the ground loop heating
capacity is never exceeded. These facts do not appear to be a good
enough explanation not modeling the back up gas boiler. 

 

My questions for the group are:

1. Is there a way to add a boiler or some additional heat source to a
ground loop in eQuest?  As far as I know the only work around I have
discovered is to represent the ground loop by creating a water loop and
adding a magical no energy consuming boiler and fluid cooler to a heat
pump water loop and change the water loop parameters to match ground
loop parameters. Then you can add normal boilers that will start if the
non-energy consuming ground loop boiler is too small for the building
heat load.  I offered this option to the LEED reviewer and they replied
that it was not an established work around.

 

2. If there is no way to attach a boiler to a ground loop in eQuest, is
there some established work around that somebody has used that was
accepted by a LEED reviewer?

 

3. Is there anything in the reports that lists the maximum and minimum
ground loop temperatures? I have been unable to locate it. 

 

4. Does anyone have an written explanation to answer "If this [the
boiler] is not being modeled in the energy modeling software then
provide a thorough explanation for why it cannot be modeled. "?

 

5. Does this sound like LEED is trying to eliminate eQuest software, and
if so, is there anything we can do about it? "in the future the software
selected to simulate the building components must be able to model those
components "

 

The project team could possibly demonstrate that the boiler would not
operate through a series of engineering calculations, some other
software that could possibly simulate the building's loop temperatures,
or through a thorough explanation of how the system operation prevents
the boiler from operating. In short the project team must demonstrate
that the boiler will not operate, not just say that is the case without
presenting some evidence. If this is not being modeled in the energy
modeling software then provide a thorough explanation for why it cannot
be modeled. In the future the software selected to simulate the building
components must be able to model those components or use an exceptional
calculation (work around) to do so (G2.2). 

 

________________________________

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