/sci/ - Science & Math

Redo the tubing using a smaller diameter and having it go back and forth in an s pattern from top to bottom. Something like the pic. If you use two layers like that, you want the water to enter the side away from the fan and leave the side near the fan. Definitely get a tubing bender to make it smooth and even. You want as much tubing in front of the fan as possible. You could even solder some copper fins to it if you want to get really crazy.

Alternatively, if you can salvage a small radiator, that would work even better.

Basically, if the return water isn't room temperature, you're not getting the best efficiency you can with your coil.