Revision as of 16:35, 28 February 2021

This one says 70% efficient - really? [1]
CFM of 20 gets 1 hp about. 1 cu m is 35 cf. 1 cu m at 190 atm is 7000 cf, at 20 cfm gives 350 minutes or almost 6 hours.
7 cfm, 0.2 hp - $250 - [2].
14 cfm gets me the right power - 0.4 hp or 300W.

Power Out

1 cubic meter of air storage - at 200atm - gets you 7000 cfm at stp. Since we need to save 10 atm to run, have 190 atm available - so 5% negligible loss - most is usable air. This is 500 minutes of air - 8 hours - of 300W - or 2.4kW hrs! This is just plain adiabatic.
Thus, having access to 1 cu m of stored air - is key.

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 *7 cfm, 0.2 hp - $250 - [https://www.ebay.com/itm/New-Air-Drive-Pneumatic-Radial-Piston-14mm-Shaft-Motor-0-2HP-900RPM-Mixer-DIY/271399029996?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D230924%26meid%3Dcadef6bd62dd4e26b2999e183e5f2b18%26pid%3D101195%26rk%3D4%26rkt%3D12%26sd%3D303335987408%26itm%3D271399029996%26pmt%3D0%26noa%3D1%26pg%3D2047675%26algv%3DDefaultOrganic%26brand%3DUnbranded&_trksid=p2047675.c101195.m1851].
 *14 cfm gets me the right power - 0.4 hp or 300W.
+=Power Out=
+*1 cubic meter of air storage - at 200atm - gets you 7000 cfm at stp. Since we need to save 10 atm to run, have 190 atm available - so 5% negligible loss - most is usable air. This is 500 minutes of air - 8 hours - of 300W - or 2.4kW hrs! This is just plain adiabatic.
+*Thus, having access to 1 cu m of stored air - is key.