80mm PC fan Recuperate heat from air in contraflow directions: air ventilation heat exchange mounting in walls or windows,Recuperate heat from air in contraflow directions: air ventilation heat exchan

Attention one fan pull one fan push air in the room to maintain the pressure constant . Recuperate heat from air in contraflow directions: air ventilation heat exchange mounting in walls or windows, 2x PC fans 80mm. Very dry PETG 0.6 nozzle PA (pressure advance) tuned and enabled. A 1 kg PETG roll was in the dryer for 12 h before printing and all the time during printing. The things can be enlarged and scaled up for using 120 mm fans, perhaps, or scaled down for 60 mm fans if using a 0.4 mm nozzle. Using a resin printer can speed up the printing a lot. I printed with the Geeetech A20 (Ender 3 clone) wave-overhangs fork of Orca Slicer. Modified my printer with a Bambu Lab 0.6 mm high flow HF nozzle. Printing time for the middle core was 24h PA enable is required and perfect for 0.63 mm walls. What I tested working is the middle core that prints excellently and can be used also for alternate flow heat recovery systems to store heat. The idea is print as many cores as you need to fit the wall thickness. The efficiency is very high and will be even higher with more cores glued together. Gluing? I have no idea how to. Perhaps a thin layer of superglue after fine sandpaper on a flat surface. Some metal guiding insert plates could be used for perfect alignment. All things are cold from a freezer or a fridge. Low temperature usage of the superglue remains liquid long enough for adjustments. I will also post a rectangular shape with fans at a45-degree angle or a straight line in the tube for mounting sideways on a window; it is working in progress on the way. Soon I will be posting. Save heat energy of the householders. Update version: https://www.thingiverse.com/thing:7412074 https://www.thingiverse.com/thing:7410023