I liked the paper case and the water cooled system that were presented here and in Odroid Magazine in the recent past. They were both great examples, one of minimalist design and the other of maximum design possibilities. They both inspired me to pursue a design I had in mind, something more practical for my application. A split air flow configuration using a single fan to cool both sides of the PCB. The majority of the airflow would be on the heat sink but some would also go under the bottom of the board. A system wide cooling approach of continuous airflow. Along with some system tuning, and as quiet as the Noctua fan is, I plan on running the fan continuously starting at 25% and upping the rpm quickly to maintain minimal temperatures across a varying spectrum of uses.
The Noctua isolation mounts that came with the 40mm fan were used for the fan and as isolation feet in the vertical position. The gold universal northbridge heat sink was rotated for better SOC coverage and the required fin orientation for side mount cooling. A battery and UART holder was integrated under the top as discussed here
and as seen above the USB3 ports in the photo below.
The nut holders double as feet in the horizontal position and help protect surfaces.
Operationally the case design has performed as expected. It has very similar performance characteristics as a top mounted fan with the additional benefit of bottom side cooling. If run passively, the vertical orientation should help heat rise away from the system and minimize thermal pooling underneath. I have a couple of other tweaks that I would like to try in the future. Adding a raised copper perch of 2-5mm to increase thermal transfer and accommodate airflow under the heat sink. If I can get sufficient airflow under the heat sink it may increase the efficiency of SOC and support chip cooling. I might try some custom duct work to direct airflow better. The OpenSCAD case design file is attached for anyone interested.
There are different case layouts, sizes and options as explained at the top of the design file. Make sure you have the XU4_Model posted herehere
in the same working directory. It has been updated to version 1.1 recently that includes supporting accessories.