Regarding the next Official Zynthian Alu-Case for the Pi4, Ramon and me are thinking about it quite a lot. Our goals for the new design are:
- Maintain size and price
- Solve heat problems. If possible, avoid fans
- Allow to connect “expanders” (i.e. ), probably using a ribbon cable
These are some of my thoughts about the heating problem with the RBPi4:
For that reason, normally, when operating without a case, the RBPi4 doesn’t get overheated. At less, this is my experience. So, in an open space (no enclosure), the “natural convection” is enough to maintain the board under 80ºC, even without a simple heatsink!!
So, the real problem is evacuating this heat from the enclosure, not evacuating the heat from the RBPi. (OK, the true real problem is maintain the CPU under 80ºC , but you know what i mean.)
The more simple way is to use a fan in the case to force convection around the RBPi4. Of course, a heatsink would help too …
The not so simple way but a lot more elegant, reliable, silent, etc. is to NOT USE A FAN. We have 2 main lines here:
Use the Alu-Case as a heatsink, “conducting” the heat from the RBPi’s PCB (CPU?) to the alucase’s chasis. And i say “conducting” in the more physical sense of the word. First, we should replace the current “nylon” separators by “brass” separators. “Brass” is a good conductor and will help to evacuate heat from the RBPi’s PCB to the case. Also, we could try to conduct the heat directly from the CPU’s metal pad, but it’s more complex and probably we will end putting a heatsink here.
Also, iw we achieve to conduct enough heat to the case surface, we could “glue” a heatsink to the case bottom, or try to integrate the fins in the design.
Add extra ventilation slots on the front-side and probably make bigger the back-side and bottom slots. We have to take all the advantage we can from the “natural convection” process. A Finite Elements simulation would be nice, but i don’t know if we can afford to do that. It’s not a 2-days work … (BTW, somebody wanting to do that? ;-))
Note that the “ventilation” slot in the front side could be used for passing the ribbon cable that allows connecting an “expander”.
Only ideas. Nothing has been tested yet … so … please, i’m very very interested in your ideas and suggestions. Don’t hesitate to post in this thread!! Let’s brain-storm, guys!