Calculation for Pipe based heat tracing

[abcmex]

Dear sirs I would like to ask your help for some published reference about heat tracing calculation.

I did already some search but I did not found anything I would define as usefull. I started by consulting the Piping handbook (Nayyar et. Al.) but there they describe very well the use of a program for calculation from a Company which is primary interested in selling electrical heat tracing (I agree this is for most of the applications better but not for all).
I also took a look at the sites of Thermon, Cromolox and Raychem but I feel they focus strongly on Electrical tracing.
In my specific case I would like to keep the product cool because it is sensitive to high temperatures therefore no chance with electrical nor steam calculations will help.

Rgs.

 

[Unotec]

Soo, you want chill tracing opposed to heat tracing?

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[unclesyd]

Aside from jacketed pipe for cooling you may want to contact Controls Southeast about their ControTrace tracing.

http://www.csiheat.com/Products/Bolt-On/ControTrace/ControTrace.htm

 

[abcmex]

Thanks unclesyd,
It is a nice idea, I saw it in an earlier post. It is probably a bit too sofisticated ($$). I expect to use tubing or a metallic hose clamped to the pipe as tracer to minimize the installation expense.

rgs

 

[Unotec]

With just a trace and not surrounding the pipe you risk not enough cooling. Think about this, when you heat trace you cover the pipe with insulation to prevent heat loss. In you case you do not want cooling loss (yes, I know, flows from hot to cold, but that's convention. Picture loosing your cold). For this reason, if ambient is not enought to cool your pipe, you're going to have to concot some way of cooling the pipe evenly.

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[Unotec]

Just thought of this, but can't you put cooling spools at intervals? say, finned piping or a cooling jacket very so many metres?

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[unclesyd]

Can you fabricate a jacketed pipe in-house?
To simplify matters you needn't jacket alway to the flanges.

I would definitely call CSI and get some budget numbers.

If you try tubing you will defiantly have to use a heat transfer mastic to improved the heat transfer.
Such as the following or the Thermon material.

http://www.csiheat.com/Products/Bolt-On/heat transfer cement/heat_transfer_cement.htm

Picking up on the idea mentioned by unotec here are some posibilites. Depending on you local and duty cycle control could be a problem.

http://www.tex-fin.com/

 

[abcmex]

Thanks for you comments.

Dear Unotec,
Yes, you are right about the insulation, if you are tracing it is probably better to do it otherwise you will not get a proper heat distribution (in my case heat collection). I have never seen a traced line without insulation and the energy prices now probably will foster the use of insulation.

About your second idea: the cooling is mainly for the time when the pipeline is idle. The heat that I want to remove is the ambient heat (sun, hot environment).

Dear unclesyd,
Jacketed pipe is even more expensive than the CSI solution. Due to the low temperature difference between the product and the medium is very likely to require heat transfer cement).

Kind regards

 

[Unotec]

Instead of removing the environmental heat, why don't you just 'insulate' from it?

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[IPGBen]

If you use "bare" tracing clamped on the piping, you better look also at the possibility of galvanic corrosion.
This is specially tricky when you also want to cool your pipes. This cooling will condense water and water together with two different materials will act as a nice battery.

Grtz
Ben