[PAID - $50] Advanced Parametric Loft Design for Portable AC (Fluid Dynamics / HVAC Focus)

I'm looking for help designing an original 3D-printable transition duct for a Midea MAP12DV1XWT-A portable air conditioner.

The idea is to print two of these for the inlet and the outlet hose of the ac unit to go under my garage door. The dimensions are based on framing the opening with standard 2×4s.

Attached is a rough sketch showing the general concept.

I'm not married to the design I have drawn. I just couldn't come up with a better way to snake it through.

Requirements:

• 150 mm (5.9") round hose connection.
• Transition from round to a 20" wide × 1.5" tall slot.
• Overall depth approximately 3.5".
• Internal cross-sectional area should remain equal to or greater than the inlet area (~27.4 in²) to minimize restriction.
• The transition should use smooth curves and generous radii rather than sharp corners to reduce turbulence and pressure loss.
• Internal surfaces should be as smooth as practical.
• Structural ribs/slats at the outlet are probably needed for strength so it doesn't get crushed by the garage door.
• Airflow efficiency is more important than minimizing filament use.

Printing requirements:

• Please divide the model into pieces that fit within a 256 × 256 × 256 mm build volume (Bambu P1S size).
• Alignment features such as pins, tongue-and-groove joints, dovetails, etc., would be appreciated.
• The assembled interior should remain smooth across seams.
• STEP files would be preferred.

This will be used for the exhaust side of a dual-hose portable air conditioner, so maintaining airflow and minimizing static pressure are the primary goals.

Any suggestions from people with HVAC, ducting, or fluid dynamics experience would be greatly appreciated.

Payment: $50 PP G&S

Open-Source Note: I plan to share this design with the 3D printing community on MakerWorld so others can solve this same garage AC problem. The final design will be published under a (CC BY-SA) license to allow for public sharing and remixes.