heat exchanger design

[Lc_shi]

Hi sirs,
I need to design fin-tube heat exchanger sometimes because we can't get specialized supplier tech support. I only can refer to the textbook formula and make the calculation on my own. The result is not too good. For each new set,we need to test and redesign. It's not a good way:p
How do you make the calculation more accurate? If there are more helpful design material or clues for fin-tube heat exchanger design,pls advise. thx!

best regards
LC

[US Iceman]

Hi LC,

Try this link...

http://www.wlv.com/products/databook/databook.pdf

This contains the basic equations for developing the heat transfer for finned tube heat exchangers.

The link above is for an older version of the book. A new version is being developed, but currently not available.

Another possible source is a book titled "Process Heat Transfer". Authors are "Hewitt, Shire & Bott". Published by CRC Press & Begell House.

This can be a quite complicated project.... Trying to calculate the film coefficients for boiling or condensing refrigerants can be frustrating. The heat transfer through the tubes, fin contact resistance, and temperature distribution through the fins can also be challenging.

On top of this you may also have some mass transfer functions for condensing water on the coils.

I believe there are some sophisticated software programs that can do this, but then again, the programs are probably more expensive than your time. As least as far as the boss is concerned. :rolleyes:

[Lc_shi]

it's a good link. thank you ,Iceman,you're alwayes helpful for us:)


I believe there are some sophisticated software programs that can do this, but then again, the programs are probably more expensive than your time. As least as far as the boss is concerned
you're absolutely correct. Boss pay more attention at cost. Labor is cheap here:p

best regards
LC

[US Iceman]

LC,

You might try looking for a PhD thesis that may be posted on the web. Sometimes you can find some very interesting material.

Most of these have the equations related to the problem.

The hard part is finding the correct topic you are interested in. It might be worth your time.

You may even find something else just as interesting too.:cool:

[Peter_1]

I sometime use software form Heatcraft or Lemmens Belgium.

What I mainly do is looking to an evaporator and calculate how many fin surface they have for ag iven capacity.

I then make a coil with different dimensions but same fin area and a face velocity of +/- 2,5 m/s.
Many manufacturers give their fin area and airflow.

I gave you also in a PM how I calculate a condensor.

Try also to find out from your coil manufacturer what k value you can use for theri coils. You can find out with a practical test what capacity a certain coil gives. You can then use the rule of 3.

[US Iceman]

Hi Peter,

What is the rule of 3? I'm not familiar with this.

Thanks.

[Peter_1]

You're defenately familiar with it, it's me trying to translate a Dutch expression in English.

If 100 cm² = 1000 W then 150 cm² = 1500 W or 50 cm² = 50 W.
In Dutch we call this the rule of 3 because

known a/known b = known c/searching d.. 3 expressions of the 4 are known in this dividing example.

[US Iceman]

I understand now. You are describing a method to scale the performance of the new coil size.

Thank you for the explanation Peter.

[Josip]

Hi US Iceman,

unfortunately from this link I can get only 7 pages TABLE OF CONTENTS and nothing more.

http://www.wlv.com/products/databook/databook.pdf

It seems very interesting book, unfortunately not reachable for me..:(

is it possible to send it by email to me or to give me some other link, thanks :)

[US Iceman]

Hi Josip,

The link below is the main web page to the link.

http://www.wlv.com/products/

Go the the bottom of the page for the links to the data books.

The link you have listed is indeed for the Table of Contents. When you scroll down to the various chapters, the individual areas can be clicked on to go that area of the book. On my browser, the different sections are shown in blue with an underline. I can click on the section and this jumps to the section selected.

The Table of Contents is the link to the rest of the book.

A new version is being developed and is listed as data book III. Some of the sections are not complete yet.

I have used this book quite a lot and find it very valuable.

If that still does not work, please let me know and I will try another method to get you the information.

[Josip]

Hi, US Iceman, thanks,

:( No way,

still get only Table of Contents. I'm using Mozilla Firefox browser and AAcrobat 7.0 Pro. When click to link I get an offer to open with AcroExch (default) or save to disc, using any result is the same :( 7 pages :)

Hope we can do that on some other (good:) ) way, ha?

[Lc_shi]

Josip,
You can download a software: http://www.xunlei.com
and use it to download them. I've already download them successfully.
have a try:)

rgds
LC

[Peter_1]

Hi US Iceman,

unfortunately from this link I can get only 7 pages TABLE OF CONTENTS and nothing more.

http://www.wlv.com/products/databook/databook.pdf

It seems very interesting book, unfortunately not reachable for me..:(

is it possible to send it by email to me or to give me some other link, thanks :)

If you click in the pdf file USIceman gave us, where you see the index, then each line is a new hyperlnik to a new section. Try this once Josip.

[Peter_1]

Josip, I copied it complete with a website copier software.
I will try to recompose it to one file and post it somewhere.

[Peter_1]

They also have another ebook on
http://www.wlv.com/products/databook/db3/DataBookIII.pdf

an apparently free software for designing coils.

[Peter_1]

All the files of databook II takes +/-16 MB
Databook III 26 MB
:eek: :eek: :confused:

How can I post this somewhere?
Forgot again that option to post it somewhere for free temporarely.

Peter

[frank]

Try this Peter

http://www.megaupload.com/

[Josip]

Hello guys,

Thanks Ic_shi, I tryed but site is in Chinese so I had to give up :) cannot find english button :)

Peter when I open or download those pages and click to some line like to hyperlink I got the message that pdf xx is not available :confused:

Download is finished within 4-5 seconds but only those 7 pages.

[Lc_shi]

enter the page
http://www.wlv.com/products/databook/

select each one and right click ,"save as" ,it's OK
try :)

rgds
LC

[Josip]

Thanks Ic_shi,

it seems to be gooood :)
now I have to put the chapters together what is not too big problem ;)

will come back when succeed :)

************************

have it all :) :)

Thanks guys

[Peter_1]

I uploaded it here the book II
http://www.megaupload.com/?d=NHCH6S49

[Peter_1]

And here book III http://www.megaupload.com/?d=2SRS7831

[Josip]

Thanks Peter,

download both books:)

Only problem is each chapter is protected and for that reason is not possible to combine them in one book :(

[frank]

Only problem is each chapter is protected and for that reason is not possible to combine them in one book

If you have Adobe on your system (I don't mean the Adobe Reader) you can print the files to Acrobat distiller and then combine them

[Josip]

Hello Frank,

Yes I have that Adobe but please :) explain how to do that. I did try :( my fingers are blue of ink ;) but no success.

Distiler ask me for ps (post script) file but all of them are pdf files.

Your hint is welcome;)

If no here send a PM or email, but maybe some other guys can use it as well :)

Thanks a lot!

[US Iceman]

Hi Josip,

I think you can also merge documents with the Adobe program. I seem to remember doing this once before.

[Josip]

Hi US Iceman,

no way becuse each document is protected and merging is not allowed :(

[US Iceman]

Hi Josip,

I was afraid the pages would not merge or the hyperlinks would be broken.

Do the links work if you have all of the sections in the same folder?

[jamcool]

try winzip,some servers can takes only small files 10mb at a time send all in parts then open with winzip. It might work

[Josip]

Hello,

just waiting for Frank's hint :)

anyhow, the most important is I have it; to open each chapter separately is not too big problem ;)

Thanks for all advices :)

[frank]

Open up one document.
Click file, print and select Acrobat Distiller.
Save the file with a new name in a location, say Desktop.

Now do the same for the other document.

Now open up one of the new documents.
Click "Document", Add Pages
Now search for the other file and select, press enter and both documents become one.

[Josip]

It start nice but....



This PostScript file was created from an encrypted PDF file.
Redistilling encrypted PDF is not permitted.
%%[ Flushing: rest of job (to end-of-file) will be ignored ]%%
%%[ Warning: PostScript error. No PDF file produced. ] %%

Anyhow, it is nice to know, protected document is always protected. It will be very sad to make and protect document with one tool and with very next one override that protection ;)

Quit the job and wash ink of my fingers :) :)

[US Iceman]

At least you have the documents in one place. I did not think they might have the security turned on for the files.

Thanks for the refresher course Frank. I could not remember how I did that.:o

[stalker]

A question about pressure drop:
Is too good bad?
When designing heat exchanger, must the new version have the same pressure drop as the original had?
Or is it just important, that the pressure drop of the new exchanger isn't bigger than original had but no problem, if it smaller?