A horizontally ducted system on top onf a building would be more aesthetically pleasing and most likely more efficient because the air is ducted.
I still dont think you can get your money out of it unless you can sell dreams to folks
. In fact, using a new mathematical model they developed from the Glendora data, the researchers found that arranging the VAWT arrays just like schools of fish produced the best results. Such tightly packed VAWT arrays can produce as much electricity as conventional windmills, all while using as little as one-hundredth of the land area. “I don’t think I expected to see as great an improvement in the land use,” says Whittlesey.
The study revealed that the most efficient arrangement involved alternating the rotational direction of the turbines: a clockwise rotation in the lead turbine, say, with two counterclockwise rotators next in line, followed by three clockwise rotators, and so on.
“these things have all been done in the study of cavetation”