Couldn't agree with your reply more. Re the flappy fan, I know I've read sometime in the past couple of years about a design that was trying to replace rotary

Couldn't agree with your reply more. Re the flappy fan, I know I've read sometime in the past couple of years about a design that was trying to replace rotary fans, and it was piezoelectric in nature. I found a few but none that looked like they would develop any appreciable pressure. I think stacked piezeoelectrics could be built up in such away that you could create a material pressure differential, but not in something the size of a tootsie roll, and not anything that could move enough volume to let people breath.