It runs by heating and some machines are so small they run just from the heat of your hand. It has few components and is therefore stable. You can heat is with a mirror parabol that consentrates the sun in summer, and in winter you can put it by your stove and produce energy from the heat that is there anyway.

But it must not become too hot, because then the gas in the cylinder will expand so much that it cannot cool down enough when it is compressed, ready for a new cycle.