Supercharger power requirement

[mender]

My apologies, as usual I'm skipping steps as I type. Since I only have the three test samples, I'm not too worried about exact numbers but I should be a little more careful when I post!

So, if we assume an efficiency of 65% in my last equation:

14.7 psi, 700 cfm, 65%: 53 hp

That will be the expected power from the compressor shaft of that particular compressor.

Which meshes well with my understanding.

It works out to about (0.004 hp/cfm*psi boost)/compressor efficiency, so the answer to my original question is 41.2 hp for 700 cfm at 14.7 psi and 100% efficiency. That's about 58.8 hp for a compressor that is about 70% efficient.

Adjusting my constant as mentioned earlier results in the lower 36 hp calculated requirement.

The 36 hp is a "pure" number, before the drive and compressor efficiencies are accounted for. Given a drive efficiency of 96% for each of two steps (pulley/belt, internal gears) and a sweet spot in the compressor map of 75%, the required hp would be 52.1 hp. Using your number of 65% with my equation results in 55.4 hp.

For me, that's close enough. With what has been covered so far, I can plot the trends which is what I was after.

0.00467 * 5.8 * 592 = 16 hp (82.6% eff)
0.00394 * 8.8 * 585 = 20 hp (92.7% eff)
0.00379 * 11.8 * 568 = 25 hp (91.9% eff)

Is this for another compressor? The efficiencies look pretty high with the correct equation.

Same compressor but I assumed an efficiency of 70% and took that out so I could compare other methods of compression and drives. Putting that back in yields 23 hp, 29 hp, and 36 hp respectively. Hope that made sense; my shortcuts don't always to others!