×
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

Another easy fan question
2

Another easy fan question

Another easy fan question

(OP)
I have another easy question about fans... well, I hope it is an easy question...

We have in our facility an oil-cooler; it works with two axial blowers, suctioning air through the finned tubes and sending it out directly to the atmosphere.
We could invert the rotation of motor and change the position of the blowing wheel, putting it backwards...

But, ¿could this increase the efficiency of the fan?... I mean, ¿it's better to put the restriction (due to the finned tubes) at the suction-side or at the discharge side, if we are looking for a better performance?

Thanks,

JuanMC

RE: Another easy fan question

With an axial fan, sucking is probably better.

RE: Another easy fan question

If Delta p acrosws the coil is the same and the fan is the same, the efficiency is the same.

You could recover the heat in the building rather than wasting in the atmosphere, but fan operation will be the same.

RE: Another easy fan question

2
In close quarters, you will get more uniform airflow and better heat transfer across the coil if you have the coil at the suction. If your fan is blowing at the coil, you would either have to place the coil far downstream where the airflow is more uniform or you would have to put a diffuser plate (a perforated plate with about 50% free area) at the fan discharge. This will involve pressure drop and loss of efficiency.

RE: Another easy fan question

(OP)
Thanks to everybody.

Willard, thanks, but we can't use the heat. It is the refrigeration of the lube oil for bearings for an electric generator, there is no use for the heat.

I was wondering if it was better; The system has had a lot of miss-designs (piping, thermal capacity under-sized, and others) that we were checking all the posibilities.

Thanks again,

JuanMC

RE: Another easy fan question

JuanMC

You might get increased flow rate if you move the motor away from fan as shown below.

from   p___|'''''|  to   p___________|'''''|
         d      |....|       d                    |....|

Provided you have the space to do so. You might be able to do this by add in a shaf coupling and a extension shaft.

Regards

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