Qidi Q1 pro convert Aux Part Cooling Fan into carbon / HEPA filter

I have no need for the internal 12032 Aux Part Cooling Fan on the right hand side. So I converted this into an internal circulation filter. It holds an off the shelf  Dreame F9 hepa filter which seem readily available in various places. Alternatively, one might replace the filter contents with carbon pellets.

In the slicer (QidiStudio, Orca) go to filament->cooling tab and set aux.part.cooling.fan->fan.speed to 50%.

Prints without supports, use filament type able to withstand the chamber temp. To install, remove backpanel and right hand side panel, unclip the top of the 12032 fan, remove the angled nozzle, install new filter holder with some glue, reattach fan top, reassemble. Verify the xy-carriage moves freely.

Attention: for design I used a generic 'Dreame D9/F9' filter. I have not investigated further but maybe it was in truth a 'F9' filter which likely is smaller than 'D9'. Also check comments from other users.