Bldg-sim Digest, Vol 19, Issue 15

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Vikram,

If you look at LEED NC CIR ruling date 2/20/2009 you'll find a similar
situation in a hospital, that was told to use PTACs. This is a situation I
looked up a while ago. I modeled my special pressurization requirement
rooms with PTACs quickly and saw the baseline used less energy than my
proposed design with the chiller / boiler. I didn't go back to look into it
in much, I've got that on my list to do. I can only think it was because
the PTACs fan and coils cycle as needed and don't need to keep running like
the chiller and boiler in the hospital. Anyone have any other insight into
this?

Good luck Vikram.

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06/18/2009 03:00 PM Subject
Bldg-sim Digest, Vol 19,
Issue 15
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When replying, please edit your Subject line so it is more specific
than "Re: Contents of Bldg-sim digest..."
Today's Topics:

1. Appendix G Zoning (Vikram Sami)
2. Re: Appendix G Zoning (David S Eldridge)
3. Re: Appendix G Zoning (David Reddy)
4. BESTTEST Certification (Harding, Ross)
5. Re: BESTTEST Certification (Linda Lawrie)
6. Re: BESTTEST Certification (Michael Donn)
7. conversion factors electricity primary energy (leen peeters)
8. VRV / VRF systems (Allison Coley)
9. Re: VRV / VRF systems (Marcus Sheffer)
10. Re: VRV / VRF systems (Julia Beabout)
11. Re: conversion factors electricity primary energy
(Cramer Silkworth)
12. Chilled Water Meter and Utility Rate (eric wang)

----- Message from Vikram Sami on Wed, 17 Jun 2009
17:22:42 -0400 -----

To: "Bldg-Sim"

Subject: [Bldg-sim] Appendix G Zoning

Exceptions to G3.1.1:

(c) If the baseline HVAC system type is 5, 6, 7, or 8, use separate

single-zone systems conforming with the requirements

of System 3 or System 4 (depending on building

heat source) for any zones having special pressurization

relationships, cross-contamination requirements, or code required

minimum circulation rates.

I?m modeling a building that has baseline system 7. If I read this
correctly then all lab spaces will have their own system and that system
will conform to system 3 from table g3.1.1A. Is that correct? If so ? are
all of my lab spaces going to be packaged single zone units? That doesn?t
seem right ? especially since lab spaces are more than 50% of the building
area in this case.

I?d appreciate anyone?s help with this.

Thanks

Vikram Sami, LEED AP

----- Message from David S Eldridge on Wed, 17 Jun
2009 17:33:09 -0500 -----

To: Bldg-Sim

Subject: Re: [Bldg-sim] Appendix G Zoning

Vikram, you should follow the exception (c) if you have a few zones in a
larger building that have special requirements, different from the bulk of
the System 7. This I think would be intended for cold rooms, server rooms,
etc.

For your case with roughly 50% labs and 50% other, you may instead want to
use the exception (a) to add a second system type in order to account for
differences in space requirements between labs and other spaces.

The design building is probably a good guide ? if you are accomplishing
your proposed design with one system, then you might find some way to use
one system 7. If you have separate lab/office AHUs in the proposed design,
then two systems under exception (a) may be called for.

Depending on the size of the lab, you may end up with several System type 3
or 4 in the baseline, but for larger labs I think the intention would be to
make two System 7?s.

You may also want to look for the Labs21 guide to Appendix G which includes
some other unrelated suggestions.

David Eldridge, PE

Shariq_Ali at URSCorp.com's picture
Joined: 2011-10-01
Reputation: 200

Allison -
Unfortunately I don't yet have experience in modeling VRF systems, but I have some info... At the moment, the EnergyPro package is the only well-established package that the major VRF manufacturers stand behind as robust. Performance curves from current VRF equipment are used in that software. You'll likely find it more cumbersome than TRACE, but TRACE's VRF system has not really been validated to my knowledge (anyone from CDS, please clarify if I'm mistaken); the VRF reps I've spoken to don't trust it.

eQUEST developer's do plan to introduce VRF in a version in the near future, but I haven't heard any recent updates on the schedule for that. That doesn't help you now, but look for it for your next project because it'd be easier than EnergyPro in my opinion.

There are also people working on a VRF module for EnergyPlus, but only at the research level. Someone who's working on EnergyPlus may have more info on that....

Scott Hackel

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Reputation: 1

All,

I wanted to clarify Scott Hackel?s comment (from Volume 19, Issue 16)
regarding TRACE?s ability to model VRF systems?

*Unfortunately I don't yet have experience in modeling VRF systems, but I
have some info... At the moment, the EnergyPro package is the only
well-established package that the major VRF manufacturers stand behind as
robust. Performance curves from current VRF equipment are used in that
software. You'll likely find it more cumbersome than TRACE, but TRACE's VRF
system has not really been validated to my knowledge (anyone from CDS,
please clarify if I'm mistaken); the VRF reps I've spoken to don't trust it.
*

Since 2002, TRACE has had the capability to model VRF systems. Through a
partnership with Daiken, we developed a cooling-only and heat pump model
based on their products at the time. Due to continued advances in VRF
systems, our original model does not adequately represent these newer
products. Because of this, we have developed a new model, available upon
request, which is in a more accurate biquadratic form and uses the latest
Daikin manufacturer?s data. If anyone has any questions, feel free to call
C.D.S. support at 608-787-3926.

Thanks,

*Michael Patterson, LEED? AP*

Michael Patterson's picture
Joined: 2011-10-02
Reputation: 0