Futurology

Certainly interesting tech. While the energy-per-massflow is pretty crap for co2 compared to water, that doesn't matter since in a sealed recirculating system it's cheap to just increase mass flow. But co2 tranistions from liquid to SC-fluid at pressures equivalent to current LP steam turbines, but at a fraction of the temperature (31C at 7.3MPa). You would need the phase change for maximum heat movement/volume change of course.

But this does mean that if your initial charge was precise enough, you could very well drive one of these power cycles with a heat source that operated only a little higher than human body temperature with significantly cheaper engineering materials (albeit at a terrible efficiency). Pretty wild to think about from a thermodynamics perspective.