Convection Cooling Raspberry Pi 4 Case

thingiverse

Originally I used the [beautiful case](https://www.thingiverse.com/thing:3723561) made by [Malolo](https://www.thingiverse.com/Malolo), to be precise the solid bottom and top cover with the hexagonal hole pattern in the center. Unfortunately, just sitting flat on the table the Rasp ran about 65 °C idle temperature, despite heat sinks on all hot chips. At some point I randomly put the case on it's long side and immediately noted the idle temperature to drop to 60 °C. But doing a 4 core stress test still ran the Raspi into thermal throttling in less than 3 minutes. But still, looks like convection may be a thing here, of course helped by the fact that the heat sink rips were now vertical. Next I replaced both bottom and top by Malolo's versions that were basically nothing full hexagonal holes. That brought the idle temperature down to 55 °C and now the stress test took 9 minutes to drive the Rasp into throttling. Better, but still not there yet. So I remixed Malolo's solid case to have ventilation slots at the top and the bottom (if the case is on it's side), but to be airtight around the hot parts of the board. Together with more clearing on the bottom of the board that led to a chimney effect or natural convection. That brought the idle temperature down to 51 °C and I stopped the stress test after 30 minutes without throttling. Though the system were stable at 80 °C, that still felt a bit too close to throttling temperatures. Last I designed a special stand that does two things: Make the whole business more stable and provide ventilation to the bottom slots the case usually rests on. Hopefully improving natural convection even further. Well, it didn't improve anything, so the bottom slots don't seem to be that important in the first place.