Edit: A bit of context... Living in a country with extreme heat and a lot of hills, many farmers need irrigation pump systems (pump up water from a pond up to a reservoir). I have for example seen people build solutions using suncells -> electricity -> electrical pumps to lift the water to a reservoir.
This got me thinking about what is the most efficient way to lift liquids by heat alone (turning heat energy into gravitational potential energy)? What different routes are there?
Let's say we have a large amount of heat available at sea level.
We want to use this heat to lift a liquid mass (say for instance 100 kg of water) 50 meters above the sea level.
What would be the most efficient way of doing this?
I can think of different solutions:
1) We could evaporate the liquid to a gas, let it rise in a pipe 50 meters, then condensate it back to a liquid. But given that the energy required to evaporate liquids is high, and that would go to waste when it is condensated again, this seems inefficient.
2) If the amount of heat is really big, we could use a boiler & power generator to generate electricity and use a electrical pump...
3) Heat pipe / thermosiphon?