This will only work during the day in the desert on a moving vehicle, preferably on abandoned RR tracks or little used back roads because of the low power density.
Water needs to be added every few miles but it's actually solar-low humidity powered.
At the front of the vehicle a small amount of liquid water is sprayed on a hot roadbed, the flow rate adjusted so that the water evaporates by the time the vehicle passes. High humidity air leaving a cooling tower is blown under the vehicle to help keep the liquid water consumption down.
The hot humid air from the road then condenses on and warms the evaporator of a centrifugal compressor refrigeration system running backwards. The cooling tower cools the condensor.
The delta T in such an engine might be 100 F so a 75 ton ac refrigerator system might put out a few hp.
Bret Cahill