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Is there a liquid or compounds that can change from gas then to liquid and back in a vacuum or with air?

In the picture below the hour glass looking devise liquid comes in contact with light or heat it vaporizes passes the neck turning a electric turbine. At the absence of heat or light it would drain back into the lower half. Water is not the only liquid that could be used. Can this work?

In a vacuum water cannot be a liquid but under enough pressure like on the lowest picture, the weight would be measured allow enough pressure for water to be in a liquid state when it is out of the sun. A balance between a super cooled liquid, gas state and heat/or light. Black dye could be added to increase performance. enter image description here

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  • $\begingroup$ I don't know how you've never seen one of these, but it's basically the same thing (en.wikipedia.org/wiki/Drinking_bird) $\endgroup$
    – Hari
    Commented Jan 12, 2018 at 2:49
  • $\begingroup$ The "Clock of the long now" uses night/day temperature difference to generate the power required to keep track of time over 10,000 years, I believe... $\endgroup$
    – Jonathan R Swift
    Commented Jan 12, 2018 at 11:12

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what you are describing here is basically a reversed heat pump that uses a temperature difference to run a heat engine in which the working fluid is so chosen as to undergo a phase change during the engine's power extraction cycle, and the high temperature source is a solar collector of some sort and the low temperature sink is night-time ambient.

Systems like this are indeed practical and extensively documented- especially in the case of using an expansion turbine to extract the shaft work, but the efficiency limiter is the temperature at which the heat is added to the working fluid. to beat this limit requires the use of a concentrating collector to get the high temperature portion of the cycle as hot as possible, but this step adds significant cost because then the collector has to be designed to actively track the movement of the sun across the sky.

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  • $\begingroup$ Isn’t a reversed heat pump a regular power cycle? $\endgroup$
    – rul30
    Commented Dec 12, 2017 at 6:16
  • $\begingroup$ yes it is. Reason for the downvote? $\endgroup$
    – niels nielsen
    Commented Dec 12, 2017 at 7:18
  • $\begingroup$ The down vote was a touch-type accident on the iOS app. I am trying to re-verse it since 1h but I get an error that I am not allowed to change my vote $\endgroup$
    – rul30
    Commented Dec 12, 2017 at 7:42
  • $\begingroup$ Thanks for your answer. Effort equals +1 when i have the rep $\endgroup$
    – Procreator
    Commented Dec 12, 2017 at 16:20
  • $\begingroup$ In a vacuum water is not a liquid but under enough pressure like on the lowest picture, the weight would be measured allow enough pressure for water to be in a liquid state when it is out of the sun. A balance between a super cooled liquid and gas. $\endgroup$
    – Procreator
    Commented Dec 12, 2017 at 17:03
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At the very basic level, this is how steam turbines or an organic rankin cycle in solar thermal power plants work.

https://www.barber-nichols.com/sites/default/files/wysiwyg/images/rankine_cycle_thermodynamic_diagram_large.jpg

However you would be limited/constrained by the volume of the lower container. By increasing its volume it takes longer to be heated. A smaller volume would heat faster but would not produce so much energy per day (cycle).

Wouldn’t the working fluid drain back into the lower container from itself (using gravity)? Is it really necessary to have a weight to help?

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  • $\begingroup$ Thanks for your answer. Effort equals +1 when i have the rep $\endgroup$
    – Procreator
    Commented Dec 12, 2017 at 16:44

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