Inquiry Regarding Entry of Ventilation Outdoor Air for PSZ System in eQuest

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To Whom May Be So Kind,

We are currently creating a Baseline Case Energy Model using eQuest for
LEED NC v2.2 for a facility that will consist of restaurants and a bar/lounge.
According to LEED NC v2.2, we need to use a Packaged Single Zone (PSZ-AC)

system for the baseline case energy model.

We have done so, but I can not find a way to program the Ventilation Outside Air?
(cfm) for the?Roof-top units (RTUs). In the Detailed Mode, I can go into Outdoor Air?
tab in the?spreadsheet section of the Air-Side HVAC System Parameters, but the?
"Outside Air?From System" box is grayed out and listed as "undefined". There are
more options in what I can insert there, and we have tried them all, but none of them?
change the end use results?of the energy model.

Currently, the energy model results for Space Heating only show usage resulting
from Conduction Losses and not from Ventilation using Outdoor Air. This is confusing?
to us, since the SV-A Report in the DOE-2 Engine reports shows Outdoor Air in the system results.

Any help to guide us on how to program the Outdoor Air (in cfm or as a fraction of Supply
Air) in our energy model would be very appreciated.

Thanks & Best Wishes!
Mark

Mark Rasmussen's picture
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Joined: 2011-11-18
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Mark,

For a LEED Baseline, you should have no reason to select "Outside Air From System". Presumably, you have already completed your Proposed model, and it is running well with the desired OA amounts specified for each zone. Just copy the OA amounts from your Proposed model zones into the corresponding zones of your Baseline. Check your SV-A reports in the SIM file to verify that the OA is correct at the zone and system levels. There are no standard reports that show ventilation loads AFAIK. You can create custom hourly reports to track system supply CFM and %OA.

Regards,
Bill

William Bishop, PE, BEMP, LEED AP

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Howdy Bill,

Thank you very much for the reply, it is informative and appreciated.
Will follow your recommended course of action.

Thanks & Best Wishes!
Mark

Mark Rasmussen's picture
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Joined: 2011-11-18
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To Whom May Be So Kind,

We are currently creating an?Energy Model using eQuest for?LEED NC v2.2?
for a facility that will consist of restaurants and a bar/lounge.?According to?
LEED NC v2.2, we need to use a Packaged Single Zone (PSZ-AC)
system for the baseline case energy model.

Currently, the energy model results for Space Heating only show usage resulting

from Conduction Losses and not from Ventilation using Outdoor Air. This is confusing?
to us, since the SV-A Report in the DOE-2 Engine reports shows Outdoor Air in the?
system results.

Any help to guide us on why the energy usage from Ventilation using Outdoor Air??
is not showing up in the results / end usage analysis in our energy model would be?
very appreciated.

Thanks & Best Wishes!
Mark

Mark Rasmussen's picture
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Joined: 2011-11-18
Reputation: 0

Hi Mark,

The loads report which shows the conduction losses does not include loads from the HVAC systems. The ventilation load doesn't show up in any of the standard eQuest reports. This is because eQuest is based on DOE-2.2 which runs in sequence every hour as LOADS -> HVAC -> ECON. LOADS calculates the loads on every space in the building according to a constant indoor space temperature and the outdoor weather conditions and then passes this information to HVAC which uses it to calculate the required response from the systems. The load reporting comes out of LOADS before HVAC does its work. I recommend digging into the DOE-2.2 documentation for more information.

There is probably a way to separate out the ventilation load in the hourly reporting functions. It's something I'm looking into but haven't figured out yet. Let me know if you find an easy way to do this.

All the best,
Dan

?
Daniel Knapp, PhD, P Phys, LEED? AP O+M

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Joined: 2011-09-30
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Howdy Daniel,

Thank you for the reply, it is very appreciated.

Yes, we know that the ventilation load doesn't show up in any of the
standard eQuest reports (such as LS-C Building Peak Load Components)
because they don't show up in the DOE-2.2 engine?reports either, which?
are the source of the eQuest reports.

However, our question pertains to the end use Natural Gas Consumption which only?
shows Natural Gas Usage due to losses from Conduction (we verified this by?
manual calculation). The Natural Gas Usage projected by the energy model
does not include any Natural Gas Usage from the ventilation air (with outdoor air).

Any idea what programming issue could prevent the end use Natural Gas Usage
from Ventilation with Outdoor Air from being included in the end use analysis?
I have been trying for a long time, and can't locate the issue. The problem is?
causing an issue with our project timeline now, so I need to get this issue solved
very soon.

Thanks & Best Wishes!
Mark

Mark Rasmussen's picture
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Joined: 2011-11-18
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Wow! This reminds me of some discussions I have had with EnergyPro
support regarding loads reports.

I use EnergyPro for LEED and Loads and it is also DOE (2.1E) based.
There is always a hassle making sure that the ventilation loads are in
the loads reports. This gives me some clues. Thanks!

EnergyPro does add the ventilation loads in eventually so the Zone and
System reports reflect those loads.

Robert Wichert P.Eng. LEED AP BD&C

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Howdy Everyone,

I removed the Simulation file as it was too large to
automatically be posted to the community.
This e-mail has just the .inp and .pd2 files.

Thanks & Best Wishes!
Mark

----- Forwarded Message -----

Mark Rasmussen's picture
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Howdy Paul,

Thank you for the reply, it is very appreciated.
The systems being modeled are Packaged Single Zone (PSZ)
Roof-Top Units (RTUs)?as in Type 3 (PSZ-AC) from?
ASHRAE 90.1-2004's Appendix G.
This is the baseline case for a LEED project.

Any help would be greatly appreciated!

Thanks & Best Wishes!
Mark

Mark Rasmussen's picture
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Joined: 2011-11-18
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Howdy Brian,

Thank you for your reply, it is greatly appreciated.
Please find the requested files attached, plus?
the current Simulation file, which may be of use.?
Any good help?could really save the day!

Thanks & Best Wishes!
Mark

Mark Rasmussen's picture
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Joined: 2011-11-18
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