Piping System Modeling

[TXEIT]

Hello all,

I have been tasked with converting a model in PIPE-FLO to an AFT Fathom model for a fairly large campus system in order to compare the pros and cons of both programs' capabilities. I have recreated the model and found similar errors on both, but I was hoping that I could understand the differences between the two a little better.

I was wondering if anyone has personal experience in both that could offer an opinion on the drawbacks on either software. Any help is appreciated, even if its simply your experience in one of the softwares. I have some experience in PIPEFLO, but almost no experience in Fathom which makes it hard for me accurately describe the differences. From searching multiple forums I realize that this is more of a personal preference based on what you will be using it for, but I'd still love to hear some experienced professionals take on either.

Thank you in advance.

 

[MJCronin]

A "model for a fairly large campus system" ?????

Give us a clue... are you modeling a steam, condensate or compressed air system or what ???

By their own admissions, AFT-Fathom has severe limitations when modeling compressible media....such as steam.

AFT Fathom is a fine, very useful design tool

If you could get some pressure drop information from the actual installation and then re-adjust your computer model of the system, accuracy would be improved.

Have you called and discussed the limitations of your situation with the AFT fathom people ?

AFT Arrow might be the best tool for compressible fluid flow..??

MJCronin
Sr. Process Engineer

 

[TXEIT]

Sorry, that was idiotic for me to not include that its a CHW distribution system to service buildings on a college campus, with 8 chillers totaling around 15,000 tons.

I realize how vague this question is, but I was just hoping to get some insight from someone who has exposure to both programs and could tell me some anecdotes or idiosyncrasies that they've noticed. Wishful thinking, I'm sure.

I will give the AFT people a call though, thanks for the advice.

 

[BigInch]

I don't use either of them but I'm pretty sure that any differences you encounter in modeling steady state flows will be within the error of your estimate of pipe roughness differences from manufacture, age, scale deposits and corrosion, or a valve failing to open all the way. Look for ease in use and entering your model and visualizing and ease of understanding and flexibility of making custom output, as well as ease of input and output. Those differences usually wind up to be much more important than numeric errors in results. Hydraulics isn't anywhere near such an exact science that you think. Keep in mind the three significant figures and you'll be fine.

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