Fan energy fundamentals - Appendix G models

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Would anyone like to share an input file (or paste the text into an email) with all the fan curves described in the EDR resource below? (Advanced Variable Air Volume VAV System Design Guide) The guide references a "New DOE-2 Fan Curves.txt" text file but I have no idea where/if I can download it. Yes, I probably could have typed it out myself by now but this gives me an excuse to post.
I offer the following curve-fit for Appendix G., Table G3.1.3.15 for any of you that don't already have it for your LEED Baseline models. (Just copy and paste into the "Performance Curves" section of the input file.):

"App G VAV Fan FPLR" = CURVE-FIT
TYPE = CUBIC
INPUT-TYPE = COEFFICIENTS
COEFFICIENTS = ( 0.0013, 0.147, 0.9506, -0.0998 )
..

Thanks,
Bill

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Bill Bishop's picture
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Was looking at it the other day - not sure if this is what you are
referring to. The file is EDR_VAV_Guide_5-2-07 (too big to attach). see
page 210 onwards.

R B's picture
R B
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Yes, that is the guide linked to below. I would like a copy of the fan curves shown in Appendix 5. I was hoping to save time if someone already has them in an input file or TXT file, rather than PDF.

Thanks,
Bill

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At first glance it looks as simple as copy-pasting into a .txt file in notepad or similar, then renaming the file extension to .inp... turns out there are a series of formatting issues that kinda threw a wrench into that line of thought.

Here's what I patched together some time back after first encountering that EDR guide. I haven't put this into practice yet for an energy model (though the guide has definitely impacted my design work), so I'd heavily advise carefully re-reading the EDR guideline's explanations of these curves before putting them to use. IIRC, some of that appendix looks like DOE2 but is really just a listing of coefficients for use beyond what's actually provided - I used my own initial judgment of what was "dollar sign" descriptive text in the INP - worth checking out before using also.

Let me know how this works out for ya, I'd appreciate if you'd share any edits you find necessary from this point.

`Nick

[cid:489575314 at 22072009-0ABB]

NICK CATON, P.E.

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Thanks Nick, RB, Paul,

I was interested in these curves so I could start modeling static pressure reset, AKA critical zone reset. I just tried the "Good SP Reset VSD Fan" curve and the savings were considerable versus the 90.1 Table G3.1.3.15 curve. The Good SP Reset curve also results in less fan energy than the "Variable Speed Drive FPLR" eQUEST library curve (discussed below in earlier correspondence). I did get this message but I'm choosing to ignore it for now:

**CAUTION**********************************************************************

In curve: Good SP Reset VSD Fan the dependent value

is exceeding the limits.

Value/Min/Max/First time: 1.305 0.000 1.000 12/31/24

Thanks,
Bill

Bill Bishop's picture
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This caution message shows that the outputted fan power ratio from the curve is greater than 1, which you normally would not want to see... could be a sign of a bad curve. I'm pretty sure though that you have a max fan ratio that defaults to some value that is greater than 1 (sorry, I don't recall the specific keyword). This value is the maximum input to the fan power curve: if the fan speed ratio is greater than 1, then so will be the output. If you set this keyword to 1 (limiting the range from 0 to 1), then the caution message should go away. It may not make much difference in energy use if there are only a few hours where this occurs.

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Bruce Easterbrook's picture
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I'd feel remiss to not reiterate where I left the discussion some months ago also: The baseline VAV curve defined by 90.1 does not paint a clear picture as to what it is representing in regards to SP setpoint strategies.

I've offered some speculation as to what conditions it does seem to be based upon from the shape and the behavior it describes, but ultimately I don't believe the curves produced by eQuest or this EDR guideline are on the same playing field as the 90.1 curve: apples and oranges.

Also, I see the images have dropped off in the emails way below, for anyone picking up on the topic today... so I've attached a copy of the discussion I have including the curve images I posted to compare/contrast some of the curves under discussion.

~Nick

[cid:489575314 at 22072009-0ABB]

NICK CATON, P.E.

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