I live in the south with high humidity and hot temperatures. Our pre exitisting raised home(two stories) is being rebuilt with a new addition added. The problem is the existing home is made of concrete and steel. The steel beams have existing 8in holes that ducts were pushed through to cool our previous home. After talking with the mechanical contractor, he said the existing beams with the 8in opening is not large enough to cool the new additional space. Our ceilings were only 8foot high and we will have to drop the ceiling in the living room to carry the air to the new addition. The mechanical contractor has considered every option and has spoken to several engineers. My question is mechanical as well as a design issue. Our home is going to be very modern and open with lots of glass facing the water on the south side. The North wall in the living room does not have any windows but I can not visualize how to decorate around the duct work. Does anyone have photos or comments of how this 35 foot long space can look sharp and handle the air duct? Are there new decorative air ducts out there that are meant to be exposed?

I'd start by getting an architect involved in your project as soon as you can. Professional architects are trained to be able to put a "whole project" together & have it "look" correctly. Not look like, "Oh, was this the contractor's answer?". Good Luck.

Look at the Unico System. It is a high velocity small diameter duct system, and should work in your situation.

Using round ducts and then painting them will suffice. Properly installed with good Hvac contractor will give the room a high tec look. But if its a home it may end up looking to commercial. Also where is the person that designed the room in the first place? Its their job to figure out how to do this without effecting the final look you asked for. That is why you paid them to do the design in the first place. What do they say about it?