AHHhhhh THe volume is not constant, you assumed the temperature to raise the pressure to 2.22 times the ambient pressure, getting the temp.

Compression is WAY more difficult than the equation you selected, the pumping is also not adiabatic so there are inaccuracies.

I do love the 3 btus, sign me up for that one, though I stand by my number of 50,000 times 3.413 or about 150,000 BTUS.

Woody