Because it is impossible to install all the air ducts in a straight line, when the air ducts are made into squares, the ventilation resistance will be greater than that of the circular tube design, and the cost of the air conditioning air supply system will also increase.
In addition, the circular tube design is more cost-effective than the circular tube design, because the surface area of a cylinder is smaller than that of a tube under the same conditions.
In the case of circular suspension, less suspension materials are used, which is safer!
These aspects fully show that the circular air duct design is better than the square air duct design!