>>16788869
There are alternatives to working fluids but all of them are vastly inferior in thermal efficiency and cost. It turns out that heating some fluid is a simple but effective way to turn heat into work.
And most alternatives still uses a working fluid because at some point you're using matter (if you're rely on chemical reactions), things like magnetohydrodynamic generators are "just" replacing the turbine with a magnetic field.
The alternative of fluid-less generators are things like photovoltaic generators that need an absurd temperature to work (like the sun) or thermoelectric generators that are ~10-100 times less efficient than a normal turbine or piston.
And if you go full contrarian and ask for a direct nuclear fission/fussion to electricity conversion then the result is just like the magnetohydrodynamic but with worse because it's far more complex and problematic on Earth (where you're forced to make it compact instead of like the Earth's magnetic field take advantage of a huge "ball")
