# How much heat do cooling fans generate?

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I cannot find this info anywhere.

## Re: How much heat do cooling fans generate?

TC wrote:

They are made to use all the energy they get for moving air around, so I
think it will be very little. I guess less than 10 Watt.

Marc

## Re: How much heat do cooling fans generate?

wrote:

It depends on the particular fan.  They actually draw less
avg. current than their labeled current but as an example,
an 80mm fan running at 3000 RPM might use 120mA @ 12V, ~
1.4W.   It's a bit beside the point though, that they're
moving air so no matter what their heat generation it was
for the purpose of removing heat.  There isn't any possible
computer configuration I'm aware of that could make fan heat
gneration an issue needing consideration.

## Re: How much heat do cooling fans generate?

kony wrote:

Actually, I'm having a discussion with someone who is using a computer
fan inside of an enclosed incubator simply to circulate air. I told
them these fans generate very little heat and he contends they his fan
was at 98 degrees inside an incubator that was only 90 degrees. I find
it hard to believe, the fan can generate an additional 8 degrees of
heat.

## Re: How much heat do cooling fans generate?

"TC" wrote:

What is being measured inside the incubator is temperature,
(or heat "pressure") not heat.  If the incubator is well insulated,
it's not hard to imagine that 1 joule of heat input per second
(i.e. 1 watt) results in an 8-degree rise in temperature.  The
temperature rises until it's enough to force out through the
walls of the incubator as much heat per second as the fan inputs
per second.  The fan's value is also in circulating the air to
distribute the heat evenly over the eggs.  In that respect, the
more turbulent the air, the better is the transfer of heat to the
egg shell.

*TimDaniels*

## Re: How much heat do cooling fans generate?

On Thu, 16 Feb 2006 15:28:38 -0800, "Timothy Daniels"

More turbulent air has no benefit.  The eggs are in an
environment that only has to keep them warm while there are
INSIDE that environment.  They do not create or 'sink heat,
and there is no need whatsoever for turbulence on them.

## Re: How much heat do cooling fans generate?

"kony" wrote:

Don't be silly.  The eggs are building protein
internally and thus are building large molecules
from small molecules.  That takes energy input,
only part of which comes from metabolizing fats
and sugars in the yolk - else why would a hen have
to keep them warm?  The deleloping eggs are,
indeed, heat sinks.  And since turbulence aids in
heat transfer between a fluid (the air) and a solid
surface (the eggshell), air turbulence helps to keep
the eggs warm.

*TimDaniels*

## Re: How much heat do cooling fans generate?

On Fri, 17 Feb 2006 18:08:10 -0800, "Timothy Daniels"

LOL

I suppose you'll be refitting all hens with fans now.

Eggs may be slightly endothermic _and_ exothermic for
periods but relatively speaking, it's a delusion to think
high turbulence is necessary.  On the contrary, such a plan
with significant turbulence may even require higher humidity
environment to keep them from drying out.

## Re: How much heat do cooling fans generate?

"kony" faked it:

As usual, Korny, you misquote to suite your argument.

I did not say anything about "hight turbulence is necessary".
I did not say "significant turbulence" is recommended.
I did not even recommend turbulence.
I merely said that turbulence would aid in transfer of heat
to the eggshell.

Korny, if you were to read sometimes and not just spew,
you might manage to make some sense.

*TimeDaniels*

## Re: How much heat do cooling fans generate?

On Sat, 18 Feb 2006 13:13:10 -0800, "Timothy Daniels"

What you are doing is going off on your deluded tangent
again that turbulence is some kind of goal.

It isn't.  The very negligable hypothetical benefit has to
be weighed against any detriments, and in the end, whether
it makes any real difference.

Turbulence will not "aid" to any real extent.  Relatively
speaking, there is not sufficient exo or endthermic
difference to even consider it.

## Re: How much heat do cooling fans generate?

Where in the above did I set *anything* as a goal?
You're too busy spewing to read accurately.

*TimDaniels*

## Re: How much heat do cooling fans generate?

On Sat, 18 Feb 2006 19:08:16 -0800, "Timothy Daniels"

You're the one that brought up turbulence, demonstrating
that you had no real grasp of the situation, with the whole
point of enclosure in an incubator to be that it's
surrounding the eggs, not trying to overcome any significant

## Re: How much heat do cooling fans generate?

Timothy Daniels wrote:

Well, after reading this group for many years and seeing Kony selflessly
give good advice to many hundreds of people I have one word for you Timmy.

<Plonk>
--
~misfit~

## Re: How much heat do cooling fans generate?

wrote:

The specific fan will have to be considered.

How "enclosed" is it?  If the losses from it are small, the
fan will indeed make it slightly warmer.

I don't think that's what is happening though, I think there
was a temp difference between one area (the heating element)
and the thermometer, and the fan only did what it was meant
to do, circulate heat better so the entire thing was close
to an even, same temp.

A very small incubator that is well insulated with a large
power hungry fan could rise 8 degrees.  There should not be
a need for such a powerful (or high RPM) fan in a small
enclosed space though, perhaps the wrong fan for the job is
used.  Even so, I tend to suspect the fan is mostly
equalizing the temp inside and to determine this one would
have to take temps in several different spots inside with
and without the fan .

## Re: How much heat do cooling fans generate?

If a fan has a rating stamped on it, like "12V @ 0.1A",
you multiply those two numbers together and get watts.
In this example, the fan uses 1.2 watts.

I would guess some of the energy becomes heat (electrical loss
in the hub of the fan) and some of the energy is mechanical,
the moving (compressing if you will) of the air. Most
of the 1.2 watts used will be dissipated inside the
hub of the fan.

If you consider the room where the fan is located
is a closed system, then the 1.2 watts is all contained
somewhere inside the room, which neatly avoids me having
to work out what work is contained in the moving air :-)

Paul

## Re: How much heat do cooling fans generate?

if the fan is rated at 12V, which they usually are. All you have to do
is to
look on the back and it may gave a rating likes 12V   0.08A,
as 80mA that is eighty millionth of one amp.

By Ohms law  V=RxI or W=VxI,
inserting the figures
Watts in power = 12 Volts times the current 0.08A which
will give a
power rating of 0.96 Watts, to you and me we can say 1 Watt of power

The modern type fans are 'brushless' and do not contain a coil
on the
armature like that of an electric motor and obviously do not need
brushes, the armature, instead they use magnetic poles on a disc the
electric
field to drive the fan uses stationary coils and uses the
'Hall effect
principle'

The advantage is a considerable reduction in electrical power and
the
disadvantage is less 'Torgue', ie the power in these types of motors
would
be useless to use as a drill etc as the only concern is of
rotation and not
pull.

The power of a conventional fan could be as high as 10 Watts or more.

Davy

## Re: How much heat do cooling fans generate?

> I suppose you'll be refitting all hens with fans now.

Yeah....thats right, they call em Battery hens..!

Davy

## Re: How much heat do cooling fans generate?

TC wrote:

The heat produced is negligible (unless maybe your fan is really faulty,
but then you wouldn't want to have it near you because of the noise).

As to the actual amount if you really want the details, you could make a
guess by looking up specifications for low voltage electro-motors, but
apart from the trivia value I don't think it's much practical use ;-)

--
Signed: Mark.

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