Cost effective CFD for HVAC. ASHRAE and some HVAC engineers are struggling with this concept. Is it a reality yet? Has anyone here seen a couple packages attack an HVAC problem successfully, and more importantly, quickly? I tried FIDAP three years ago and had the worst time with preprocessing. I've seen pheonics, and it's fairly easy, at a reasonable cost. Any input would be greatly appreciated.

(1). First of all, I don't think you are reading my messages. (2). My definition of CFD is " Numerical Analysis and mathematical modeling in Fluid Mechanics". (3). So, the training is very important. The engineer must have adequate training in numerical analysis, and knows the modeling process. (4). Many companies, large or small, do not understand the definition of CFD. They have been using the CAD software concept or philosophy in doing CFD. That is completely "wrong". (5). The incorrect approach is going to make the industires very bad. I have seen many companies taking this approach, developing codes, streamlining codes, optimizing codes, integrating codes with CAD, graphic packages and other codes, training engineers how to use the codes, etc... (6). If CFD is like CAD, then the flow problems would be solved long time ago, and you would not be looking for a perfect package and asking the question right now. (7). But, looking from the other direction, everyone has his own 24 hours, and resources. So, he is free to do his own thing, I guess. (8). By the way, who is suppose to develop this perfect package? Where should he learn how to do it? And who is going to hire him? (9). And if I wrote a two-line program, the first line says this is the perfect cfd package, and the next line says your problem is done, would you consider this as the most efficient code? (10). Friend, if the school does not teach you "how to write a perfect cfd code for HVAC", and if the industry does not hire such student, then only God knows where to get such perfect package. (11). I think, we can do some analysis, but we don't know how to create a perfect cfd package yet.(or is there is need to do so?)

Alright, then. First of all, I haven't read your messages, because I just got here. It may sound odd, but periodically new people come to any forum, and they haven't read through every thread (although I did look for relevant topics before i posted one). If you have something specific for me to read, please cordially direct me to it, and I'll go looking for it with due zeal. Second, I was not asking for plug and play simplicity, with no education and no effort and instant solutions and so forth. I've worked with enough experts in the CFD field and seen enough applications to know better. What I was asking for is, again: among the available packages, can someone help sift out those that are particularly suited for commercial HVAC duty?

Flovent, CFDesign should work fine.

www.cfdesign.com

It can handle these needs.

(1). Welcome to the madness of CFD. Sorry for this un-conventional style. (2). You are free to ask any question about the commercial cfd codes in HVAC.

take a look at www.airpak.fluent.com

Fluent does the job fine for me! (Better than my own codes I have written in the past). And as built designs have worked as CFD predicted - thus validating commercial code.

For which company did you use it with?

I am using Phoenics to study internal ventilation and so far it seems to offer me what I need.

Other cfd codes written more with the language of the hvac comminity include -

i)Sabre - Simulation technology ii)Flovent - Flomerics in conjucton with BSRIA. iii)FLAIR from CHAM - Phoenics derivative. iv)VORTEX - AWBI and Patel

All are uk based.

You might like to look at the relevant journal literature to see how the codes are applied to study specific hvac problems in your area of interest. There you might also get a view on validation/performance

...or are you the Nik Lane who works for Fluent?

No, I work in the steel industry.

From our experience HVAC design has different tasks to achieve. And unfortunatly I do not know of any tool which does everything at a time.

1. optimize the flow field due to pressure loss, mass flow and temperature distribution in components like air-intake, the box a) where all the flaps are located which should spread the air into the different ducts and b) where evaporator and heater are located, the ducts themselves, the air outlets and last but not least the compartement itself 2. achieve comfort criteria for the passengers 3. develop the air condition device

For the different purposes different tools are used for example in the automotive industry

1. To work on the flow field 3D CFD tools like STAR-CD and Fluent are mainly used. Together with appropriate CAD-Systems (CATIA, Unigraphics, Ideas) and meshing tools (ANSA, ICEM, pro*am) car manufacturers are working with 5 to 10 engineers permanently on that topic. You may have a look at <A HREF="http://www.adapco-online.com/frontpage.html">http://www.adapco-online.com/frontpage.html</A> where you can learn about STAR-CD's capabilities in quite high detail. A similar page for Fluent does not exist (as I know). You have to contact Fluent via <A HREF="http://www.fluent.com">www.fluent.com</A>

2. To judge the comfort of passengers I know of two codes at the moment who can deal with this task. The first one is not available on the market because it is an inhouse tool at Daimler Chrysler. Fortunatly there is one to buy and that is INKA/TILL which is sold by the company I am working for. Have a look at <A HREF="http://www.puz.de/pz_seite_e/l_spkt/sw/sw_inka_till_e.htm">http://www.puz.de/pz_seite_e/l_spkt/sw/sw_inka_till_e.htm</A>

3. For this task tools are needed which can simulate a network of many components like pipes, condensers, valves etc. Many tools are commercialy available like Flowmaster ( <A HREF="http://www.flowmaster.com/">http://www.flowmaster.com/</A> ), GT-Cool ( <A HREF="http://www.gtisoft.com/gtcool.htm">http://www.gtisoft.com/gtcool.htm</A> ) or Kuli-AC (from Steyr-Daimler-Puch in Austria). My company also sells a code which works very well together wit INKA ( <A HREF="http://www.puz.de/pz_seite_e/l_spkt/sw/sw_klan_e.htm">http://www.puz.de/pz_seite_e/l_spkt/sw/sw_klan_e.htm</A> )

So the eierlegende Wollmilchsaus (a german term for what you and everyone in that business is looking for) does not exist.

And, this is mainly for John, from an engineers point of view, although things are still very time consuming and only a very small portion of engineers who are working in that field have realy deep knowledge of CFD, the products are becoming better in a way which would not have been possible to achieve without CFD

(1). Thank you very much for the detailed information. (2). Where is the best place to fit a carbon filter on a 93 Nisan Sentra, to solve the pollution problem for my son. (3). It is not possible to cover the air outlets in the passenger's side. There are too many outlets. (4). So, is it a good idea to place the carbon filter at the inlet side below the windshield wipers? Could that block the air also (air flow reduction)? How do you handle this problem (invention)? (5). Driving in the polluted air on congested L.A. highway is not fun for my son. And he is using an electric fan with carbon filter attached to a power transformer.

(1). To judge the comfort of passengers, do you include carbon filter in your design and analysis? (2). How do you determine the air quality in a car? (3). At the UC/Irvine campus, there is a sign in front of a building which prohibit cars idling next to the side walk, because I think the air inlet of the building is also on the other side of the side walk, and it tends to suck the car exhaust into the building. (4). Do you think that CFD can be used to design a clean HVAC system for the buildings and cars?

AT PRESENT I M DOING M.E. [CAD/CAM] FROM V.J.T.I.-MUMBAI, INDIA . MY FINAL SEM. PROJECT IS GOING ON AND NY TOPICS IS TO DO MOMEALLING AND ANALYSIS OF CENTRIFUGAL PUMP WITH THE HELP OF CFD FOR THIS I USE CFD-RC SOFTWARE. AFTER COMPLITING M.E. I M INTERESTED TO DO Ph. D. SO GIVE ME RELEATED INFORMATION ABOUT UNI. FINANSHIAL ADD. ETC. BYE

Kyle, I am currently working on adding some specific building HVAC functionality to STAR-CD. The product will be called EZBaRT (no I didnt come up with the name), it stands for EZ Building and Room Thermofluids. There are at least two packages out there now from our competitors that are trying to meet that need. Namely Flovent from Flomerics and AirPack from Fluent.

Certainly get some info on those codes and see if they meet your needs. If you can wait a few more months we will (hopefully) be releasing a beta ourselves in January.

I am very interested in getting a handle on the specifics of what problems people in the HVAC industy want to solve. Certainly those that pertain to the component level performance are probably best handled with a general purpose code, Like our STAR-CD or that other code who's name I forget.

I would be interested in getting a problem statement, as a check on the work I am doing. We think we know what you folks want to calculate but....

If you have the time I'd love to chat about this. Drop me a direct email if you'd like.

Good luck and welcome to the wonderful world of CFD. Just remember, it's a tool not a magic bullet.

- Andy Robertson Program Manager EZBaRT adapco USA www.adapco.com

[fghabboon]

Hi there ,

I wonder if CFD is necessary for HVAC ? While many building engineers do not understand Bernolli equation ? and in reality , they do not know , when they use a pressure gauge , what term in Bernolli equation they measure ?

Also , most design cases in HVAC are repeated , i mean , there are almost an off-shelf design , and on off-shelf comfort model for every case .

I feel CFD , may be required by industry , in which making a model is not feasible .

Thanks

[cdegroot]

Originally Posted by fghabboon

Hi there ,

I wonder if CFD is necessary for HVAC ? While many building engineers do not understand Bernolli equation ? and in reality , they do not know , when they use a pressure gauge , what term in Bernolli equation they measure ?

Also , most design cases in HVAC are repeated , i mean , there are almost an off-shelf design , and on off-shelf comfort model for every case .

I feel CFD , may be required by industry , in which making a model is not feasible .

Thanks

Hey did you notice this thread is more than a decade old? Do you have a new question?

[fghabboon]

Hi there , Unfortunately i have not recognized that was a decade thread ..
Thank you for bringing the attention ..