What would be the Specific Impulse of a steam-based propulsion system like this model in space?

Are there any types of engine that works this way?

Could 2 tanks be designed to rotate slowly in space creating micro gravity in the tanks. The tank facing the sun would boil the water to the other condensing tank to cause the water to move a turbine similar to the sand moving past the neck of an hour glass?

enter image description here

Both tanks condense and boil depending on the orientation to the Sun. A sun synchronous orbit would be optimal.

Gravity or rotation may not be needed if the tanks are placed on the opposite sides of the spacecraft or satellite in non sun synchronous orbits.

Can a satellite utilize gravity gradient stabilization, solar power, electrodynamic tethering and dynamic quadrupole momentum at once?

  • 2
    $\begingroup$ Still there is intuition and creativity in this question, which may not be answered by googling it. Addressing water phase changing energy density and water refueling in space issues could be some kind of an answer, without other people to do an engineering evaluation. $\endgroup$
    – user19132
    Commented Mar 26, 2019 at 0:17
  • 2
    $\begingroup$ Actually some interesting options here, using en.wikipedia.org/wiki/Stirling_engine but possibly the better question is 'can a heat engine out perform solar cells for space energy generation'. Suspect no but possible case if making in situ (making pipes vs solar cells from local materials. For this particular setup thermal inertia of the tankage will make it very heavy per unit energy produced, and have dead periods during the rotation. $\endgroup$ Commented Mar 26, 2019 at 2:49
  • 1
    $\begingroup$ I think this is an interesting question. You wouldn't want the rotation speed to be too fast because you want basically all the fluid in the tank in the sun to boil off. $\endgroup$
    – zeta-band
    Commented Mar 27, 2019 at 20:10
  • 2
    $\begingroup$ Specific impulse has nothing to do with your question; since your system does not have any propellant. Please try to understand the terms you attempt to use in your question. $\endgroup$
    – Antzi
    Commented Apr 4, 2019 at 6:23
  • 2
    $\begingroup$ As mentioned by Antzi isp should not be used to describe your idea, since there is no thrust generated. On the other hand, converting heat difference to generate power has already been researched, mostly with free piston stirling engines and Seebeck generator. $\endgroup$
    – user19132
    Commented Apr 4, 2019 at 7:44