Well now I guess I have to do the math:
W = P(b)V(b) ln(P(a)/P(b))
(https://en.wikipedia.org/wiki/Compressed_air_energy_storage)
CPAP requires roughly 10 cm of water pressure = 0.01 Bar
Sea level atmospheric pressure is roughly 1 bar
So the device has to pressurize to 1.01 Bar
Now I’ve looked it up, and a typical CPAP machine moves 20 to 60 liters per minute
Let’s say 30 liters per minute = 1800 liters per hour
W = (1.007)(1.8)ln(1/1.007) = (1.81)*(-00698) = 0.0127 MJ = 3.53 Watt Hour
So assuming perfect efficiency you would still need 28.64 watt hours of battery, just to do the compression.
470 Wh/kg for Zinc-air battery implies this device requires a 60gm battery (2 oz to those of us of a certain age)
I looked up CPU fan efficiency (what they say they derived it from) and PEAK fan efficiency only approaches 25%
http://www.nmbtc.com/fans/white-papers/fan_efficiency_import...
So, you’d really need an 8 oz battery hanging from your nose to make this work, not counting what you need to run the electronics, etc.
W = P(b)V(b) ln(P(a)/P(b))
(https://en.wikipedia.org/wiki/Compressed_air_energy_storage)
CPAP requires roughly 10 cm of water pressure = 0.01 Bar Sea level atmospheric pressure is roughly 1 bar So the device has to pressurize to 1.01 Bar Now I’ve looked it up, and a typical CPAP machine moves 20 to 60 liters per minute Let’s say 30 liters per minute = 1800 liters per hour
W = (1.007)(1.8)ln(1/1.007) = (1.81)*(-00698) = 0.0127 MJ = 3.53 Watt Hour
So assuming perfect efficiency you would still need 28.64 watt hours of battery, just to do the compression.
470 Wh/kg for Zinc-air battery implies this device requires a 60gm battery (2 oz to those of us of a certain age)
I looked up CPU fan efficiency (what they say they derived it from) and PEAK fan efficiency only approaches 25%
http://www.nmbtc.com/fans/white-papers/fan_efficiency_import...
So, you’d really need an 8 oz battery hanging from your nose to make this work, not counting what you need to run the electronics, etc.