Another easy fan question 2

[JuanMC]

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

 

[MintJulep]

With an axial fan, sucking is probably better.

 

[willard3]

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.

 

[lilliput1]

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.

 

[JuanMC]

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

 

[mk2000]

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