Does the dot in the equation indicate multiplication? So should the equation read CFMS X 0.0013 + A?
The reason I am confused is that they use X in other places.
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Thanks in advance
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Vikram Sami, LEED AP BD+C
Yes that is correct.
Constant Volume Systems (3-4): (CFMS X 0.00094) + A
Variable Volume Systems (5-8): (CFMS X 0.0013) + A
William Mak
yes. the dot means multiplication. it would also be nice if ashrae
used parenthesis more, but they don't for some reason.
http://wiki.answers.com/Q/What_is_a_MDAS
Yes that is correct, the dot means multiplication.
The Excel calculator will come in very handy (credit to 7 Group)
Jorge E. Torres Coto
Keep in mind that calculator is only for 90.1-2004. Calculations have
changed substantially for 90.1-2007. Less restrictive for larger
systems, more restrictive for smaller systems.
James Hansen, PE, LEED AP
There is a second tab in the Excel calculator for 90.1-2007.
Tyler Thumma, EIT, LEED AP
Actually the calculator has both the 2004 and the 2007 in separate tabs.
Jorge E. Torres Coto
Very nifty - don't know if anyone was curious, but this checks out
against the math in my personal spreadsheet.
Out of pure curiosity, does anybody else combine their baseline system
efficiency calcs (i.e. EIR) alongside their fan power calcs, or is it
normal to submit that separately... or not at all?
NICK CATON, E.I.T.
A word of caution if you are using this 2007 tab of this spreadsheet. The pressure credit is being calculated for the entire supply fan cfm. It should only be calculated for the design airflow through the device. While these two airflows can be the same, often they are not.
Michael Rosenberg, CEM, LEED AP
answer: yes.
typically i submit the wizard input screens showing the input
efficiencies for packaged units & don't submit the eir unless asked.
most reviewers who are familiar with equest realize that equest will
break out fan energy when calculating eir. on central plant systems i
will show it for the chiller(s) along w/the fan power calculations as
there isn't a chiller input in the wizard mode.
Here's my attempt at doing that - let me know if this makes sense.
Basically what I've done is separate out the supply fan energy and the condenser and compressor energy to give you an EER (and EIR for eQUEST) for just the cooling side.
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Vikram Sami, LEED AP BD+C
That is correct. This issue has been fixed in the updated spreadsheet
attached.
Tyler Thumma, EIT, LEED AP
>From time to time we?re asked in LEED-Clarifications to break up the total
fan-power into relief, exhaust, supply etc. Can somebody tell us what to do?
The calculation in the proposed is totally different and for the baseline we
only use the 90.1 equations.
Johannes
Von: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] Im Auftrag von Sami, Vikram
Gesendet: Dienstag, 8. M?rz 2011 17:11
An: bldg-sim at lists.onebuilding.org
Betreff: [Bldg-sim] Appendix G - Fan power
Does the dot in the equation indicate multiplication? So should the equation
read CFMS X 0.0013 + A?
The reason I am confused is that they use X in other places.
Thanks in advance
We've moved! Please note our new address.
Vikram Sami, LEED AP BD+C
The 2010 version of Appendix G provides some good guidance.
G3.1.2.10.1 The calculated system fan power shall be
distributed to supply, return, exhaust, and relief fans in the
same proportion as the proposed design.
Michael Rosenberg, CEM, LEED AP
This is a good question and isn't specifically addressed in Appendix G 2007. It does specify to match the proposed design's fan arrangement so this can be used as a starting point. On a recent job we did with return fans, the overall fan power was split 70/30 between supply and return. Another job that used power exhaust fans split out to 80/20. As Michael mentioned, Appendix G 2010 says that they should be proportioned out the same as the proposed design although that information often needs to be extracted from the design team.
Andrew Craig PE, LEED AP
What is the best list to use when looking for information regarding
Equest?
Thanks;
Wes
equest-users at lists.onebuilding.org
Thanks Vikram for your help.
I?m gonna search the archive and post were the answer can be found.
Johannes
Von: Sami, Vikram [mailto:Vikram.Sami at perkinswill.com]
Gesendet: Dienstag, 8. M?rz 2011 19:41
An: Hopf, Johannes
Betreff: RE: [Bldg-sim] Appendix G - Fan power
In that case ? for the baseline the Fan power limitation ? is for the ENTIRE
building ? supply and return. You calculate your total allowable and then
break it down based on the ratio in your designed building. Sop for example
if your designed building has a supply to return fan energy ratio of 3:1, you
would first calculate your total allowable fan energy, and then separate it
by supply and return in the ratio of 4:1.
There?s been some extensive discussion on this topic in the past on this list
? you could probably find it in the archives somewhere.
We've moved! Please note our new address.
Vikram Sami, LEED AP BD+C
Von: Andrew Craig [mailto:AndrewC at InterfaceEng.Com]
Gesendet: Dienstag, 8. M?rz 2011 19:49
An: Hopf, Johannes; bldg-sim at lists.onebuilding.org
Betreff: RE: [Bldg-sim] Appendix G - Fan power
This is a good question and isn?t specifically addressed in Appendix G 2007.
It does specify to match the proposed design?s fan arrangement so this can be
used as a starting point. On a recent job we did with return fans, the
overall fan power was split 70/30 between supply and return. Another job
that used power exhaust fans split out to 80/20. As Michael mentioned,
Appendix G 2010 says that they should be proportioned out the same as the
proposed design although that information often needs to be extracted from
the design team.
Andrew Craig PE, LEED AP