If you're going to cut down the mains 240VAC down to 24VAC, you may as well just use a toroid transformer suited to the job (with a 10:1 winding ratio) to do it and avoid all this really unnecessary (and probably a hell of a lot more expensive than the toroid) switching gear to get it to switch with the precision you want.
Also: Trying to force something to switch part through a cycle will lead to a very ugly waveform, which would not be a nice thing to try and calculate the actual power for.
One other thing of note: There is a reason zero-cross switching devices exist - You probably don't want to switch something on mid-cycle every cycle.
While I applaud your thoughts Dust, I seriously doubt the practicality.
Also: Trying to force something to switch part through a cycle will lead to a very ugly waveform, which would not be a nice thing to try and calculate the actual power for.
One other thing of note: There is a reason zero-cross switching devices exist - You probably don't want to switch something on mid-cycle every cycle.
While I applaud your thoughts Dust, I seriously doubt the practicality.
