Thank you for your reply, here is some additional information.
I am interested in using heat from the cooling and exhaust systems of a IC engine to create steam power to be added back to the IC. I know this has been tried in the past with varying degrees of success/failure. The simple way to get the water is from the IC cooling system which needs to be protected from freezing. If no practicable solution exists chemically, then a heat transfer from cooling system liquid to steam system water. Steam system water may have to drained and refilled in winter, which reduces the practicality of the engine.
It is highly desirable to convert waste heat to some combination of reduced weight to hp ratio/reduced specific fuel consumption. First I would convert excess heat to steam, and use the power to compress air to boost the IC. This would reduce the power to weight ratio. An IC has practical boost limits quickly overcome. Additional power from the steam would be coupled to the crankshaft at varying hp and rpm (lol! I laugh with you ha ha). I am intending an engine approximately 40 hp 2,700 rpm (rpm IC crankshaft) weight of 75lbs. Currently IC engines are capable of fuel consumption around 0.3 lbs per hp per hour (D-Motor in Belgium has dyno charts for 0.28 lbs per hp per hour on there engines), with computer controlled EFI and CDI. Waste heat energy recovered and mechanically coupled to the crankshaft will lower specific fuel consumption. Thank you Blane.