Different versions of eQuest produce different results?

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Hi all,

Is anyone aware of any bugs in eQuest that modify specifically the space cooling energy results? A LEED model was originally produced in version 3.64 build 7130, and when I run it in my later 3.65 build 7154 (without making any changes) version the space cooling increases from 60,000 kWh to 2,300,000 kWh! Note the heat pump supplementary variable also changes, but not by 3,000%.

I noticed that in the PS-H report my chillers are working (in the later version) and in the previous version they are all in 0s. Note nothing was changed, just re-ran in different versions.

I have searched, but haven't found any bugs related to these specific versions. Any thoughts would be much appreciated.

Thanks in advance,

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Veronica Ochoa's picture
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I know there were modifications as to how heating and cooling where calculated.
But are you using the same weather? TMY2 versus TMY3? Just a thought?
Can you share your model to the forum for the "geniuses" to dissect?
John R. Aulbach, PELos Angeles, CA

Hi all, ?Is anyone aware of any bugs in eQuest that modify specifically the space cooling energy results? A LEED model was originally produced in version 3.64 build 7130, and when I run it in my later 3.65 build 7154 (without making any changes) version the space cooling increases from 60,000 kWh to 2,300,000 kWh! Note the heat pump supplementary variable also changes, but not by 3,000%. ?I noticed that in the PS-H report my chillers are working (in the later version) and in the previous version they are all in 0s. Note nothing was changed, just re-ran in different versions. ?I have searched, but haven?t found any bugs related to these specific versions. Any thoughts would be much appreciated. ?Thanks in advance,
| | Veronica Ochoa | Consultant |
| d? +44 20 7535 3750 |
| t??? +44 20 7535 3100 |
| e???veronica.ochoa at hurleypalmerflatt.com |
| www.hurleypalmerflatt.com |
| ? |

| View company email disclaimer at: http://www.hurleypalmerflatt.com/disclaimer.html |
| Please consider the environment before printing this email. |
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John Aulbach's picture
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What percent of the energy is for cooling in the before and after, and which one makes more sense?

First though is maybe an error in the earlier version. The magnitude change you are talking about sounds like the original version may have had a small packaged unit running, but not your central chillers.

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David Eldridge's picture
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This just happens. None of these models or model versions are "100%
accurate" for estimating consumption. They will vary from version to
version in ASHRAE 140 tests. I'd like to see that different versions of
mature software stay within 5% on each end use, but that's all I'd expect.
For example, check out some Trane Trace results:
https://www.trane.com/content/dam/Trane/Commercial/global/products-systems/design-analysis-tools/analysis-tools/trace-700/ASHRAE%20140-2007%20Results%20-%20v63.pdf

They are 10-20% different than the mean of the comparison suite on a bunch
of different test cases. Is that a problem? Not necessarily.

Simulation is useful for estimating differences in consumption much more so
than actual consumption. If you can pin one end or one point through
calibration of some kind, then your actual savings estimates mean
something. Likewise, if you are just using a model to say whether design
change A or design change B uses less energy, then the model can give you
that kind of decision-making data input.

My advice, which I think is typical practice, is to keep the same software
version for all runs of a given building, even if you go back to it 3 or 4
years later.

Justin Spencer's picture
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