PDA

View Full Version : Piping Design Manual







ErnieA
13-06-2008, 07:08 PM
Hi!
I am looking for a good NH3 piping design manual. At the moment, I am interested in the proper design for thermosyphon oil cooling systems.

If possible it should includes lists of good and poor practices so that existing systems can be checked quickly and accurately.

Thanks!

US Iceman
13-06-2008, 07:37 PM
The only semi-public sourced document I am aware of is published by Frick. You might contact them for a copy.

US Iceman
13-06-2008, 07:40 PM
I just noticed you are a controls company. If you don't mind my asking: Why are you getting involved in system design?

Billy Ray
13-06-2008, 09:11 PM
Hi US Iceman,

on matters of pipework design, can you recommend guide for refrigerant flow velocity in the suction, liquid & discharge pipework or.. do you look at pressure drop in pipework.

Any info appreciated.

Billy Ray

US Iceman
13-06-2008, 09:59 PM
Good question.

It depends.:D

You have to know the full load pressure drop because this is the upper limit before your design assumptions are thrown out the window and the specific component performance is affected. It's important to remember any change in pressure also creates a fundamental change in saturation temperature. These temperature variations affect the rating point for the component.

On the other hand, you need to know the refrigerant velocity (especially for suction lines or risers) to ensure oil return back to the compressor.

So... in my mind it's not one or the other....it's both.

You have to look at the full load and part load operation to ensure the system works! Then you have to evaluate whether the system works efficiently at these conditions. (which is another can of worms unto itself)

Grizzly
13-06-2008, 10:00 PM
Billy Rae and ErnieA.

Follow the link below.
It's not exactly what you want but there is lots of relevant info in the manual provided.
Cheers Grizzly

http://www.heatcraftrpd.com/resources/wiringdiagrams/H-ENGM0806.pdf

US Iceman
13-06-2008, 10:21 PM
Hey Grizzly,

The link you provided is a good place to start for reviewing piping, etc. However, I think it's prudent to forewarn everyone... thermosyphons are a unique animal and you have to be careful in designing them. Some of the standard assumptions used for traditional piping are not valid with thermosyphon systems.

Just thought I'd add my two pence for what it's worth. ;)

Billy Ray
13-06-2008, 10:32 PM
Thanks Grizzly / US iceman,

As i expected, not straight forward, but good info to keep (thanks Grizzly).

Firstly i will say i am a '***** boy' only. I have always looked at pressure drop, typically 1-2 psi max for suction line, 2-3 psi for discharge & 2 psi for liquid pipes.

Other figures i have been advised on is 1000-1500 feet/minute for suction pipes & 1 m/s for liquid.

All from good old reputable sources.

Does the above fall in the right 'ball park'.

Billy Ray

US Iceman
13-06-2008, 10:44 PM
Yep, the values you posted seem to be in line with what I remember too. However... I can't emphaize this enough...you have to look at all of the operating conditions. Full load is only one of the operating points.

Grizzly
13-06-2008, 10:49 PM
Hey Grizzly,

The link you provided is a good place to start for reviewing piping, etc. However, I think it's prudent to forewarn everyone... thermosyphons are a unique animal and you have to be careful in designing them. Some of the standard assumptions used for traditional piping are not valid with thermo syphon systems.

Just thought I'd add my two pence for what it's worth. ;)
No problem Iceman.
As usual a good point well presented.
In my eagerness to help I missed the vital point....
Thermosyphon!
I will have a check I may be able to help if Frick have still got something available.
I will check and get back.
Billy Rae there is also a really good Dupont Piping Handbook out and about somewhere.
I think Nike posted it a while back??
Cheers Grizzly.:o

Grizzly
13-06-2008, 11:06 PM
Yep you were correct Iceman.
Frick do do a paper on Thermosyphon Oil Cooling.
But at 2.5 meg it's to big for me to email. I resently tried to send someone some files and my ISP rejected the upload.
So I am at a loss as to how to get round this problem at the moment?
So I can't help, Besides as you point out ErnieA works for a controls Company????
So I am also a bit dubious as to the use it would of been put to?
Perhaps Ernie could explain?

Grizzly

US Iceman
14-06-2008, 12:14 AM
...my ISP rejected the upload


Stupid internet...:p

nike123
14-06-2008, 07:14 AM
Billy Rae there is also a really good Dupont Piping Handbook out and about somewhere.
I think Nike posted it a while back??


It is still here! (http://www.mediafire.com/?ndmvnea4otd)

Also one manual is here (http://www.mediafire.com/?9w3lxecx1b0)

And another one
(http://www.mediafire.com/?5nam2dyzaxz)

nike123
14-06-2008, 07:23 AM
:off topic:

US Iceman, what is your time zone.
It looks like Australia, because, it cannot be more hours in US then here.;)

abet_meneses
14-06-2008, 02:03 PM
ErnieA,

Good reference is IIAR chapter 1 for NH3 pipe sizing.

US Iceman
14-06-2008, 04:07 PM
US Iceman, what is your time zone?


On the clock used by the forum it's GMT-5.

Sometimes I'm just still awake in the late evening/next morning.:)

ErnieA
15-06-2008, 02:10 AM
Yep you were correct Iceman.
Frick do do a paper on Thermosyphon Oil Cooling.
But at 2.5 meg it's to big for me to email. I resently tried to send someone some files and my ISP rejected the upload.
So I am at a loss as to how to get round this problem at the moment?
So I can't help, Besides as you point out ErnieA works for a controls Company????
So I am also a bit dubious as to the use it would of been put to?
Perhaps Ernie could explain?

Grizzly

I'm confused. The last time I looked, I was a registered mechanical engineer, not a controls company. Sure, we have a refrigeration controls company but does that make it wrong to fine tune the controls and refrigeration systems we are involved in??

Anyway, thanks for all the suggestions.

ErnieA
15-06-2008, 02:24 AM
ErnieA,

Good reference is IIAR chapter 1 for NH3 pipe sizing.

Thanks for the reference! I am planning to purchase this book.

Billy Ray
15-06-2008, 08:21 AM
Thanks Nike123 - good info

Peter_1
15-06-2008, 09:42 AM
Yep you were correct Iceman.
Frick do do a paper on Thermosyphon Oil Cooling.
But at 2.5 meg it's to big for me to email. I resently tried to send someone some files and my ISP rejected the upload.
So I am at a loss as to how to get round this problem at the moment?
So I can't help, Besides as you point out ErnieA works for a controls Company????
So I am also a bit dubious as to the use it would of been put to?
Perhaps Ernie could explain?

Grizzly

You could pots it for free on megaupload.com and then post he link here.
I'm anyhow interested in it.

US Iceman
15-06-2008, 04:55 PM
I'm confused. The last time I looked, I was a registered mechanical engineer, not a controls company. Sure, we have a refrigeration controls company but does that make it wrong to fine tune the controls and refrigeration systems we are involved in??


Well, it's just when I looked at your website it appeared you were providing control systems and that sort of thing and I simply wondered why a controls company was involved in system design.

Especially thermosyphons as there is nothing to control on them. So, I was just curious as to why a control company was interested in designing thermosyphons. That's all.

ErnieA
16-06-2008, 08:51 PM
I'm confused. The last time I looked, I was a registered mechanical engineer, not a controls company. Sure, we have a refrigeration controls company but does that make it wrong to fine tune the controls and refrigeration systems we are involved in??


Well, it's just when I looked at your website it appeared you were providing control systems and that sort of thing and I simply wondered why a controls company was involved in system design.

Especially thermosyphons as there is nothing to control on them. So, I was just curious as to why a control company was interested in designing thermosyphons. That's all.


No Problem :)
Thanks for your assistance.