Cooling with just one rad

[trn]

I've always wondered about simply placing a rad in a big tank of water

You will very slowly heat up the water and eventually the water tank will act as a not very good radiator and disipate the heat into the air. The larger the surface area of the tank the more effective of a radiator it would make.

Now if anyone lived near a lake, sinking a 100m or so of tubing on the bottom of a lake and using that to radiate heat into a lake would work pretty damn good I think. Kinda like a nuclear power plants often do A river or stream would work well with a radiator I would think, keep some flowing water moving over the rad.