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I need to use an embedded computer outdoors, and I don't know how the CPU temperature will change according to the outdoor temperature. What would be a good approximation? For example. If my CPU works (inside a metallic cabinet) at 75 degrees when outdoors it is 20 degrees, what could be the highest outdoor temperature so my CPU works below 100 degrees? It only has a passive heatsink.

chicks
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ignacio
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    https://physics.stackexchange.com/ – Gantendo Jul 11 '22 at 08:02
  • thanks! I will create there! – ignacio Jul 11 '22 at 08:29
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    After taking a look at some of the questions, I don't want this question to be left in a void like [this](https://physics.stackexchange.com/questions/193810/temperature-modelling) one. Because it requires more empirical knowledge of computers, I'd rather leave it in this stack exchange. Is that ok @Gantendo? – ignacio Jul 11 '22 at 08:32
  • https://www.pugetsystems.com/labs/articles/How-Ambient-Temperatures-Affect-Your-PC-158/ "What this data specifically tells us is that the ratio between the rise in ambient temperature and the rise in component temperature is very close to a 1:1 ratio when it comes to CPUs. For video cards, the ratio is a bit less than 1:1, so the ambient temperature does not affect GPUs as much as CPUs." – Gantendo Jul 11 '22 at 08:44
  • I would add a small fan to the side of the heatsink, to draw away heat. Otherwise, your CPU will under-clock to reduce the core temperature. – spikey_richie Jul 11 '22 at 09:23
  • I have seen this article, that is also why asked about the linear relationship @Gantendo. I was expecting some empirical answers if that actually corresponds to reality – ignacio Jul 11 '22 at 10:26
  • @spikey_richie does that make sense even inside a closed cabinet with no holes? – ignacio Jul 11 '22 at 10:27
  • The ambient, the enclosure temp, heatsink and CPU lid are all going to be different and measurable. The action of moving enclosure temperature air over the heatsink will still help it shed some heat. Can you vent the enclosure with a fan too? One drawing ambient outside air in, and one exhausting the hot air out of the cabinet? – spikey_richie Jul 11 '22 at 10:35
  • Unfortunately, there will be no fan inside – ignacio Jul 20 '22 at 09:09

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The biggest problem with a computer is getting rid of the heat inside the cage. This process is really slow. The colder the outside temperature is, the better this is for the pc.

In almost all cases, the temperature outside will not affect the computer that much, especially when a passive cooling system is active without fans.

The only caveat here is that the computer should not be exposed to direct sunlight, as this will effectively heat the metal of the computer making it nearly impossible to dispose of any heat, and that will cause the internal temperature rise upto 100 degrees and more.

LPChip
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  • that is exactly my issue. I plan to test the system in a place where the temperature could reach 35-37 celsius degrees ... And because it is supposed to work outdoors, it could have direct sunlight in the cabinet. – ignacio Jul 11 '22 at 10:24
  • Can the enclosure be shielded from direct light with a small roof? A bit like this one? https://www.ecotecco.com/products/aems/ – spikey_richie Jul 11 '22 at 10:36
  • I can check this small roof solution. – ignacio Jul 20 '22 at 09:12