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View Full Version : Minimum distance to obstructions on entrance side of fan?



rooibos
20-08-2009, 01:58 PM
Good day,

I have to determine the distance between wall and one axial fan.
Is there someone who can help?

Thank you.

rooibos
20-08-2009, 05:05 PM
Come on men, I'm sure that someone can help.

nike123
20-08-2009, 07:54 PM
Good day,

I have to determine the distance between wall and one axial fan.
Is there someone who can help?

Thank you.


Half of height of heat exchanger.

goshen
20-08-2009, 08:36 PM
Half of height of heat exchanger.
hi this is a rule of thumb if u get the point !!!
most hvac manufactures recommend the right distance between their prouduct and obsticales:eek:

Ration_Tea
20-08-2009, 08:52 PM
We need more information! You could use the rule of thumb, but that is not good idea.

:off topic: I won't be enable to check this tomorrow, so reply asap.

Gary
20-08-2009, 09:04 PM
He didn't say anything about a heat exchanger. Apparently he just has a fan and a wall.

rooibos
20-08-2009, 09:09 PM
Well. Thanks for your answers.

The situation is as follow:

Four resistors 2000x2600x1000 (WxLxH).
Each resistor has two axial fan for cooling purpose.
They are situated outside on a platform. Both fans suck air from the side which is 2000mm. The vendor requires 2000mm free area to be sure that all fans can get air. I think that this is quite conservative, but also I would like to check or with some calculation what is the min. distance between the fan and the wall.

I really appreciate your kind cooperation on that matter.

Regards,

Brian_UK
20-08-2009, 10:49 PM
Come on men, I'm sure that someone can help.Please do not be so impatient. :( Not everyone is waiting here just to answer your question as soon as you type it.

People work, live in different parts of the world or may simply not know the answer.


hi this is a rule of thumb if u get the point !!!
most hvac manufactures recommend the right distance between their prouduct and obsticales:eek:As stated here, most manufacturers will give you the minimum measurement.


Well. Thanks for your answers.

The situation is as follow:

Four resistors 2000x2600x1000 (WxLxH).
Each resistor has two axial fan for cooling purpose.
They are situated outside on a platform. Both fans suck air from the side which is 2000mm. The vendor requires 2000mm free area to be sure that all fans can get air. I think that this is quite conservative, but also I would like to check or with some calculation what is the min. distance between the fan and the wall.

I really appreciate your kind cooperation on that matter.

Regards,You have answered your own question.

The manufacturer know their own product and do not make suggestions without thought.

US Iceman
21-08-2009, 05:18 AM
The generally recommended minimum distance between a axial fan intake and the back of a cooling coil for example is about 1.5 times the diameter of the fan. Don't forget air is a fluid. If you restrict the fan intake area you are adding pressure losses that the fan must overcome. The pressure losses are static pressure, which is what the fan performance is rated on.

Anyone remember air turning vanes? Similar problem here.

rooibos
21-08-2009, 06:55 AM
The generally recommended minimum distance between a axial fan intake and the back of a cooling coil for example is about 1.5 times the diameter of the fan. Don't forget air is a fluid. If you restrict the fan intake area you are adding pressure losses that the fan must overcome. The pressure losses are static pressure, which is what the fan performance is rated on.

Anyone remember air turning vanes? Similar problem here.

Thank you Iceman.
I'm not going to change the manifacture's requirements. I just thought if there is a way to check this requirement.

Cheers,
rooibos

US Iceman
21-08-2009, 02:53 PM
You always follow the manufacturers directions.

I know. No one reads the directions until after a problem pops up.;) However, if you follow the directions and a problem develops then it is up to the manufacturer to fix.

If you have the space, additional distance between walls or obstructions and air intakes is always a good thing! The other factor that has some influence on this is air velocity. More velocity, higher losses...