(As a side note to GP: Reducing/stopping pressure on the exhale is problematic also... for some of us many of our problems are actually on the exhale.
If they cared about power consumption, they could presumably make it less leaky and use check valves to prevent issues with stale air or inability to breathe if the fan stops working.
I've used snorkels with separate in and out tubes and check valves to route the air correctly. It solves stale air problems (which are irrelevant for snorkling because the total air volume is much less than the amount of air you breathe in per breath) and causes serious suckage (because you really want your exhaled air to displace water that comes in the intake, and check valves prevent that), but for CPAP it might make sense.
I've never used on of these devices so I'm curious about it.
How do you exhale? If it's forcing air in at a decent pressure then does it detect an exhale or are you expected to just push on through?
It seemed like from the video they airing would add pressure to the inhalation and switch off for the exhalation, or at least that's what I'd try and do, but then I don't know much about these things!
I'm not sure if this device is plausible, but I know this calculation is not useful. You're calculating the mass of air moved, which, first of all, does not itself say much about the energy required to do so; for instance, horizontal motion doesn't require any net energy (though any real device doing so will of course need to do something to accelerate and decelerate, there's nothing to say it can't be very, very cheap). Second you appear to be discussing it as if there isn't a pair of lungs right there providing motive power. I do that much moving of the air every day (plus a bit, probably, I'm a tall guy) with no batteries at all.
This thing is not responsible for "moving all that air"... it's responsible for a pressure increase of the air, which is at least somewhat equivalent to saying it's responsible for "moving air" but only a fraction of the value you computed. They say it is supposed to do from 1 to 20 "centimeters of water". According to the Great and Mighty Internet, 20 cmH20 is 0.02 atmospheres, just to give some perspective. I do not have the math to calculate the energy requirement that represents when the air is in motion itself; my physics would only be sufficient to calculate the energy implied in pressurizing a closed container from 1 to 1.02 atmospheres, which is useless in this case. Perhaps someone else can pop up for that.
(Bear in mind I took a full standard College physics-for-non-majors course set, using full calculus, and what I know from that is that what I know is inadequate... if that also describes your experience, your education is inadequate too. We're going to need to hear from someone with more specialized education.)
My suspicion is that yes, this device is plausible, but the final version is going to be larger than the versions shown. Whether it crosses over the invisible line where people become unwilling to wear it is anybody's guess, but... sleep apnea sucks and those masks do suck too, so there's some room for these guys to work in. I'd classify this as a "considered risk" rather than "two orders of magnitude impossible". I reserve the right to change this assessment as more data comes in, especially a (good!) physics analysis of the real energy required to do this.