@WilliamRamsey I love the design. The fan size seems to favor flow volume over flow pressure. Given that the intake seems to be more omnidirectional than the existing air, I would suspect that it could be a higher performer if the filtration medium is being pulled through. A smaller fan size could make the velocity sufficient to push air.

I base this off the server fans that take low pressure air and push it out at velocities high enough to make white noise painful.

The bag would perform well enough in either configuration. If it were mounted in a rack server I would recommend the pull configuration with ducting in a 2U size so it can pull enough cool air using the negative pressure from the rest of the server in addition to the fans.

This configuration would help keep the dusty bag from being inside the server when it needs to be changed. The 2U Duct could be pulled, changed and reinstalled quickly.

It's just a thought about how it could be made to perform a little better. Those fans don't seem to mind pulling through light filters on PCs. The bag seems to be a good match for the flow pattern with the lesser pull from the top and higher pull from the center. The bag provides a reservoir of sorts so the pulling pressure doesn't need to be higher. In a push configuration the fans get dusty and the resistance of the filter medium could cause more problems due to turbulent air and a slight bit of compression of the air.

I would suspect that the flow would not be affected much with this design. Your design is rather elegant and deceptively simple. Very good work.