[Bldg-sim] CFD Software for Built Environment

[Paul Carey]

Antixs, et al
 
Airpak is okay and is perfectly adapted to HVAC applications as it includes
fan details, etc allowing you introduce swirl, etc.  It is expensive for
what you get though.  It has improved, but the gridding was fairly rough and
ready if you get complex geometry and can throw a wobbly if you are doing
external flow analysis for things like pedestrian comfort assessments where
you could need large variance in your grid cell size.  If you are doing
rooms, etc you'll be fine.  I'd agree with Kai's comments though.
 
Not used FloVent.  It's quite pretty from memory, it's outputs are well
suited to HVAC work and make the whole CFD (Colour For Directors) stand up.
Whether it is good for complex analysis I'm not sure and will have to leave
that to others to comment on.
 
CHAM's flair is HVAC specific and there is even a link with Hevacomp so if
you've done your room calculations in that then there is a reduced version
which will let you do some basic flow analysis.  
 
The problem with most of these simplified tools however tends to be the
gridding which has a tendancy to let them down and so convergence of
solutions can be hard to achieve.  It really does depend on what you are
going to use it for and what sort of problems.
 
Sorry about copying your message below to the list Kai, but I think others
will lose the thinking of the thread and my comments as well, hope you don't
mind.
 
Cheers
 
Paul
 
 
From: Kang, Kai [mailto:Kai.Kang at jacobs.com] 
Sent: 10 September 2008 14:52
To: antixs antixs; Paul Carey
Subject: RE: [Bldg-sim] CFD Software for Built Environment


Antixs, 
 
Both Airpak and Flovent are customized CFD programs for building HVAC
applications.  Airpak wraps around the basic Fluent solver, and provides a
user-interface that is much more geared towards building engineers, as well
as some additional functions that is only available with Airpak, such as
solar heat gain.  
 
I have some experience with Airpak a while ago, being a Fluent user for many
years, I did not find any problem of learning the program and will say an
engineer without prior experience should be able to pick up the modeling
pretty quickly - the problem, however, is that if there is any issue with
the model, such as if the solution is diverging, it is very difficult to
"debug" the model in Airpak.  I assume the same would be for Flovent, so in
essence I would say they provide the easiness in "cookie-cutter"
applications. 
 
I am not copying this to the entire mailing list, as I may be talking a bit
too specific. 
 
 
Regards,
Kai

  _____  

From: antixs antixs [mailto:antixs.antixs at gmail.com] 
Sent: 10 September 2008 14:36
To: Paul Carey
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] CFD Software for Built Environment


Paul,
Thanks for such detailed information! They are really helpful. Do you have
any experience with Airpak and Flovent? Heard that these two tools are
specially tailored for built environment.

Thanks again.

antixs


On Wed, Sep 10, 2008 at 4:39 PM, Paul Carey <Paul at zed-uk.com> wrote:


Antixs
 
I think this depends largely on your budget and proficiency.
 
If you want to go full on with CFD, then I'd suggest Fluent
(http://www.fluent.com/) everyday.  It is very widely used and well trusted
tool.  ICEM is a good meshing tool, but we like Pointwise and Gridgen for
it's meshing simplicity.
 
Other than that, I know CCM+ from CD-Adapco (http://www.cd-adapco.com/) is
very good too.  Makes the job quite easy.  These tools are very expensive
though.
 
If you want the same sort of capability and are willing to use mainly text
input then I'd suggest OpenFoam (http://www.openfoam.org) - a very powerful
open source CFD tool.  You could use something like pointwise to mesh it,
output a fluent case file and then openfoam has it's own fluent case file
converter program which you could use to then convert it and process it.
You'd probably need a decent post processor too, but clearly then you are
only paying for those programs as openfoam itself is free.    If you can do
it all by text then you wouldn't need to pay anything at all.  It will
require you to use Linux though.  I saw a pre-compiled bootable live CD
distro of this recently which was quite impressive so it allows you to check
it out just by inserting CD into computer and booting to it.  The link for
that is:  http://www.caelinux.com/CMS/
 
 
Of the cheaper and possibly more usable programs for quick built environment
analysis.  Cham Pheonics (http://www.cham.co.uk/)  is good value for money.
It's Flair add on is pretty simple to use.  I'd still personally get a good
CAD program to make sure your geometry is spot on before importing it, but
then it would do the job well.  A lot of companies use it becasue of it's
relative simplicity and good price.
 
Another which is aimed at non-CFD experts is DesignBuilder CFD
(http://www.designbuilder.co.uk/).  It is in beta test stage and looks
promising.  It'll be great for simple stuff.  Wouln't recommend anything
that uses just cartesian grids for complex jobs, but for the large majority
of jobs it will suit, especially if it's internal room flows, etc.  Should
be quite competitive on the price too.
 
Hope that helps.
Regards
Paul
 

Dr Paul Carey
Director

Zero Energy Design Ltd
10A Portland Place
2-22 Mottram Road
Stalybridge
SK15 3AD
UK

T:  +44 0161 3386200
F:  +44 0161 3031281
M:  +44 0789 4098012
E:  paul at zed-uk.com

http://www.zed-uk.com/
 
 
 
 
 
 

  _____  


From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of antixs antixs

Sent: 10 September 2008 05:13 

To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] CFD Software for Built Environment


Hi all,
 
Just wonder what CFD softwares are popularly used for analyzing built
environemnt in architect/MEP consulting firms? Also which one is relatively
eaiser to use?
 
Many thanks.

No virus found in this incoming message.
Checked by AVG - http://www.avg.com
Version: 8.0.169 / Virus Database: 270.6.19/1661 - Release Date: 9/10/2008
6:00 AM





No virus found in this incoming message.
Checked by AVG - http://www.avg.com
Version: 8.0.169 / Virus Database: 270.6.19/1664 - Release Date: 9/10/2008
6:00 AM


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20080910/3ef4c142/attachment-0001.htm>