Holy frijoles, Batman! 12kW power dissipation?! I missed the beginning
of this thread - how big is this enclosure? I would think that you
need to take a step back on this design. I would not want to rely on
active air-conditioning to take care of that heat load from a
transformer, for safety reasons.

Does this mean that your total input power is 120kW? (90% efficiency)

Sean


On Tue, May 4, 2010 at 6:43 AM, Moreira, Luis A <Luis.Moreira@ccfe.ac.uk> w=
rote:
> Hi All,
> Thank you very much for all your replies.
> The conclusion that I got to, is that the all thermal management for
> this enclosure is very badly done and it would explain why everything is
> "cooking" in it. This enclosure as a air cooled transformer in it which
> as losses of about 12KW (optimistic estimation for 90% efficiency), to
> maintain a feasible 45 degrees C the air as to be changed at least every
> 0.42 Seconds if ambient is 35C. This is clearly not feasible.
> I need to start thinking about cooling the air intake.
>
> Best Regards
> =A0 =A0 =A0 =A0 =A0 =A0Luis
>
>
> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
> Of Olin Lathrop
> Sent: 29 April 2010 16:12
> To: Microcontroller discussion list - Public.
> Subject: Re: [EE]: enclosure cooling.
>
> Marechiare wrote:
>> That's not always true. Turbulence does not always help to cool
>> better. Imagine a computer case with silent radiators inside and a
>> single fan in the case. Non - turbulent air may stream at higher
>> speed.
>
> I was saying turbulence is generally better at the same speed.
> Certainly
> fast laminar can be better than slow turbulent.
>
>> The molecules may get heated by radiation too
>
> Not in any meaningful sense to this discussion. =A0Air is basically
> transparent to IR for this purpose.
>
>> or through air
>> heat conduction mechanism as well.
>
> Meaning convection, apparently, which is exactly what this discussion is
> about.
>
>
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