[Equest-users] question about inefficiency of duct

Varkie C Thomas thomasv at iit.edu
Thu Mar 31 10:55:38 PDT 2011


Nick,
The website consists of my notes for teaching at IIT and case studies based on my experience at SOM.  It was a hasty part-time effort.  The website is paid for until December 18.  
Some of the eQUEST models will generate 1000s of pages of Warning & Caution messages.  I have never used eQUEST on a real project.  The DOE21E models (that I might add later) are based on actual projects and might be more useful.  See http://bepan.info/design   5 - Energy-Savings-Options
The Excel programs were created to solve specific project problems and they are not generic programs (could be developed into generic) that could be used on other projects.  
I will continue adding the stuff lying around in my computer (from all the junk created when I was working at SOM and teaching at IIT) to the website until December 18.  I still have to add my notes on Electrical, Lighting, Plumbing, & Fire-Protection. 
Those with an engineering degree and a few years AE design experience do not need the information in the website. It is intended for teaching architectural students.  
Varkie

----- Original Message -----
From: Nick Caton <ncaton at smithboucher.com>
Date: Tuesday, March 29, 2011 7:18 pm
Subject: RE: [Equest-users] question about inefficiency of duct
Varkie,
I�ve found your website fascinating, personally. 
I�m not currently an educator, so perhaps I�m not the intended audience, but as an MEP designer actively practicing energy modeling in industry (outside of academia) I�ve stumbled into and found the BEPAN site to be very handy multiple times. Anyone who hasn�t perused the site might want to dig around a bit� there�s quite a few tools/spreadsheet examples provided which I�ve found interesting-to-useful, though finding any one thing can be tricky as it�s quite a lot of material!
I hope the site doesn�t go down, or else if it should have to you�ll give us a fair warning to scramble and make copies of useful references/tools =). It seems to exist solely as a good-faith contribution to helping others learn from your past experiences, and for that I hope you know I for one very much appreciate your efforts!
Thanks,
~Nick

NICK CATON, E.I.T.
PROJECT ENGINEER
Smith & Boucher Engineers
25501 west valley parkway
olathe ks 66061
direct 913 344.0036
fax 913 345.0617
www.smithboucher.com 
From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Varkie C Thomas
Sent: Tuesday, March 29, 2011 6:38 PM
To: Paul Diglio
Cc: equest-users at lists.onebuilding.org; xiaoyang shi
Subject: Re: [Equest-users] question about inefficiency of duct
See page 14 to 17 "Thermal Analysis"
http://bepan.info/class-notes/e6_-_loads-ducts-pipes 
AES-Ductwork-System-Design
When the cooling DT (Room-Suppy Temp) is 20 degs, every degree temp rise from the cooling coil affects the supply air by 5%. For a draw-thru system with a supply static of 8" to 9" the heat gain across the fan, the temp rise can be significant. The rule of thumb in the old days, when no one could be bothered doing these calculations manually, the temp-rise was assumed to be = 0.5 x SP. 
The velocity upstream of the terminal box from the AHU through the unconditioned shafts of high-rise bldgs is typically about 4,000 fpm which results in low heat gain due to the high velocity. The terminal box and the low velocity ductwork is above conditioned space (typically RA plenum). If the ductwork is insulated on both sides of the TB, the rule of thumb for a temp rise through the ducts is about 1 - 2 degs which requires about a 10% increase in supply air.
Before anyone replies to this message saying that it has wandered off the point from the issue being discussed, I will admit the reply is an excuse to for mentioning the website. I am thinking of closing it down if there is no interest from others in developing building energy analysis course material from a full design perspective and not just using computer program. The emphasis would be on teaching Energy Efficient Building Design with project case studies. It does not quite fit in with BEMBook The objectives are in the Introduction http://bepan.info/introduction
Varkie
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