×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Outlet Air Temperatures in Air Cooled Heat Exchanger

Outlet Air Temperatures in Air Cooled Heat Exchanger

Outlet Air Temperatures in Air Cooled Heat Exchanger

(OP)
Hello...!

Is there a limitation in Outlet Air temperature in Air cooled Heat Exchanger?
Is it possible to have the air at temperatures greater than 100°C when leaving the exchanger?
 Thanks for the answers...!

G

RE: Outlet Air Temperatures in Air Cooled Heat Exchanger

Dear Peregrino7,

The answer is clearly yes and no.  

The yes part:  The outlet air temperature can never be higher than the process inlet temperature.  If you are designing a cooler, there are some practical limitations as well.  Induced draft fans don't work as well in an extremely hot air stream.  (Forced draft is definitely better in such a case).  Also, the closer the air outlet temperature is to the process inlet temperature, the lower the LMTD.  This is usually sorted out when desiging based on the economics of the cooler.  Typically, the air outlet temperature is somewhere about the middle of the temperature range of the process fluid.

The no part:  As long as the process temperatures are hot enough, and the heat transfer coefficient is high enough, the outlet air temperature can be as high as it needs to be, within the limitations mentioned above.  For example, if you have a cooler for a hot heat transfer oil at, say, 250 deg C with a short cooling range, the air outlet temperature could easily be well above 100 deg C.  In such cases it would be a good idea to keep the cooler well clear of personnel, however.

Regards,

Speco (www.stoneprocess.com)

RE: Outlet Air Temperatures in Air Cooled Heat Exchanger

Normally the outlet air temperature is only limited by the metallurgical limitations of the cooler's materials of construction, usually dictated by the hot side.

I've seen 600°F easily reached on Combustion Air Preheaters, but I have also seen processes (in this forum) where the same type APH was unsuitable because the flue gas was too hot for any reasonably priced metal to handle.

rmw

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources