Calculate valve heat loss 1

[mfqd13]

Hi,

I'm calculating some valves heat loss.
Until now, i have been using a calculation method that uses a conversion from the valve diameter to equivalent pipe length, and then calculate normally as if it is a pipe.
Now i'm trying to validate this conversion factors, or to make some more accurate calculations?

Can anyone share with me how can i make this calculations??
Thanks!

 

[MortenA]

Heat loss is through the surface area - and i would assume that

A) Inside film coefficient is low
B) Conductivity through the body is good

Thus the main resistance in the outside film!

I think you metode is fairly good - but why not just use the length and diameter of the valve and use the same methode as for pipe (be it horizontal or vertical).

Best regards

Morten

 

[mfqd13]

MortenA

That is why i puted there this post. To obtain from other experiences if my method is correct, or if, for example, i should only consider de length and diameter of the valve, as you mentioned...

I will wait for some more replies...
Thank!!!

 

[ione]

Marcosdias,

Take a look at page 4 and table 4 (page 8) of the attached paper. This could help you to check your calculations.

I hope it could help.

 

[mfqd13]

Dear ione,

GREAT!
Thanks! That confirms my idea and with this i can adjust my conversion values.

ione, i have another post related to trace lines, witch is the subject of the document that you've attached. That heat loss tablens can be used also for the case of steam tracing?

Thanks for this reply! It was very helpful!

 

[ione]

This reading may help you.

 

[mfqd13]

Dear ione,

You're great man!!!
thanks once more. I will take a look mor calmly to compare this equations to the standard ones for pipe heat loss to understand the differences.

Conincidence that a few hours ago i was searching in Cheresources and found the excel sheet related to this document. Having the formulas is much better to understand this.

THANKS!!

 

[abcmex]

Dear Mr. Dias,
if you visit the site

http://www.spiraxsarco.com

you will find some information about heat tracing.

In some contries with high labor cost the tendence is to install electrical heat tracing but also to use metallic hoses (

http://www.witzenmann-sachsen.de/download/Flexibles Begleitheizungssystem_1347_2_04_09_3_web.pdf)

Dear Ione,
the file is very interesting and therefore one star,
although I have never seen a tracer never on the top of the pipeline.

rgs