It has been some time since I looked at Mr. Icy Ball. It might go a bit like this.
Two propane bottles piped together. One filled with activated charcoal and just saturated with water (tank A). Tank B might be empty at this point. The rig might be under vacuum or pressure, can’t remember (chemo brain and old age ). Heat tank A until all the water condenses into tank B, thermo battery. Allow to thermally normalize. Oh, maybe vacuum because now tank A will (fingers crossed) absorb the water from tank B thus cooling tank B and heating tank A. Could we make an engine with this Mr. Bob?