Since in this engine there is no loss of the working medium, we can use various, even more expensive liquids. It can be Methanol with a boiling point of 60 degrees Celsius, or even diethyl ether with a boiling point of 36 degrees Celsius .. these temperatures are for normal pressure, i.e. 1 atmosphere. When the pressure drops, so does its temperature. We can even reach 10 degrees for ether, but we have a problem with cooling the distillate should be at least 0 degrees, which we can only achieve in winter, by cooling it with the temperature of ice or negative air temperature.
Andrew
