Here's an interesting thesis from 2008 that will bore most, but if you shift thru it, there's planty of useful tidbits like this...
- regen load.png (303.41 KiB) Viewed 14331 times
In this thesis, the author critiques 2 models (1) solar (2) combustion biomass, and this graph is for one of them. I don't remember the cycle specs, so this graph is not a constant. Nevertheless, it demonstrates just how much greater regen heat can exceed input heat per cycle (rpm). Even with .95 regen, when you're volume ratio is under 1.5:1, you're beating a dead horse unless you have a mile high thermal ratio. Yep, the infamous "regen load" (aka 'load' amongst the gurus) which I spent years gaming. Once you get to 6:1 volume ratio, you can kiss regen goodbye...