Thermoengine HSF Mod

I know I know, this HSF is really old, but it has a good design and efficient cooling. ((Hey Vantec Aeroflow coppied the concept.))

Because the Thermoengine is such an old HSF I have decided to mod it, by inserting a copper surface with the center of the HS filled with distilled water.

Any concerns or suggestion (liquid types, coin types etc.) would be much apreciatied.

thx