I had an idea a while back to increase the power output of small scale HAWTs that are mounted on houses. Build a metal funnel on the side of the house (or two, one for each side of the HAWT) that focus the wind onto the HAWT and increase the speed.
Would this be the same as having a HAWT the same size as the large end of the funnel?
I have a simple garden windmill mounted on a pole by the side of my house, and this turns almost all the time (about 7 feet off the ground). I realise that mounting the HAWT inside a funnel means that it won't receive wind from all directions, but then, if it's in the middle of a 30 feet long wall, there isn't going to be much wind blowing directly onto the wall (if you choose the right side of your house!), and winds that are, say, 20 degrees off the side of the wall will still go into the funnel and most of their energy will be preserved until they hit the turbine, (correct me if I'm wrong).
It would also be possible to build houses next to each other with an angle of 10 or 20 degrees, with, say, a 2 feet gap between them at one end, where you put a line of turbines up the wall. The other end might be 30 feet apart, and you would then get very high wind speeds through the narrow gap.
You then have all the benefits of a large turbine (i.e. a 30 foot one) but by using 7 or 8 with a 2 foot diameter.
Small is beautiful, as Schumacher said.
Do any of you know of any research into concentrating devices like this, on HAWTs or VAWTs?