On Teggy, there's a about a 12"x2" removable plastic gap above the battery, in the wiper "parking area". I removed it this past summer to let the engine bay breathe a bit.
Since the weather has been cold then warm again this Fall, I have noticed heat waves from the opening and felt significant hot air movement while stationary.
I haven't had a day of frost to test the theory or to melt frost/ice/snow, but if the opening's air is directed toward the driver's side, or a similar gap made on the other side, it may be a way to move waste heat onto the windshield (granted, you would have to protect underhood components).
Another variable is what exactly happens to that region of the vehicle at speed? In my limited understanding of aero, I recall that the wiper area tends to trap air -- so it may be moot as you drive.
All of this depends on a warm engine.
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On a side note, I had to get the "As Seen on TV" windshield cleaner
It doubles as a defogger of sorts so the inside stays clear.
RH77