Convection Cooling Raspberry Pi 4 Case

thingiverse

I used the beautiful case made by Malolo, specifically the solid bottom and top cover with a 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 its long side and immediately noted the idle temperature drop to 60 °C. However, doing a 4 core stress test still drove the Raspi into thermal throttling in less than 3 minutes. It seems that convection may be a real factor here, of course helped by the fact that the heat sink rips were now vertical. Next, I replaced both bottom and top with Malolo's versions featuring full hexagonal holes. This brought the idle temperature down to 55 °C, but the stress test still took only 9 minutes to drive the Rasp into throttling. So, I remixed Malolo's solid case to have ventilation slots at the top and bottom (if the case is on its side), while keeping it airtight around the hot parts of the board. I also cleared more space on the bottom of the board to create 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. Although the system was stable at 80 °C, that still felt a bit too close to throttling temperatures. Finally, I designed a special stand that makes the whole business more stable and provides ventilation to the bottom slots the case usually rests on. Hopefully, this would improve natural convection even further. However, it didn't make any difference, so the bottom slots don't seem to be that important in the first place.