Isotherm Freeline 140 Fan Tray

The Isotherm Freeline 140 and 70 are very poor at temperature regulation.  Circulation fans are absolutely required, but using the common D cell powered ones is a pain (they take up shelf space, are loud, perform poorly, and require new batteries every week).

Designed and 3D printed a perfect drop in 'tray' which takes the place of one of the sliding windows to the freezer section. The tray has a perfect spot to drop in a Noctua 12V fan. The tray just sits in the shelf by gravity without any issue. I aimed my so it blows down into the fridge - drawing that cold plate air and getting it moving down. I added a second of the same fan zip tied to the bottom side of the lowest wire tray. I have them hooked up to an ESP32 controller so I can adjust their rpm using pwm signaling. Tons quieter, never need to replace batteries, fans are up and out of the way and don't sacrifice valuable shelf space.

And they work fantastic. I can now keep the upper shelf at 33F and the lower at 36-37 even with the fridge set on power level 3 out of 5. I keep having to turn down the fan speeds or I'll freeze things - running them about 40% most of the time.