Great idea, for a "tough times" chiller, I had considered doing something similar or going all the way to a coil in mini-fridge, with a pump hooked to a controller. But I have such high cooling needs that I bought a 1/4hp JBJ chiller just so I didn't have a constant job or a PITA project. If you need chilling very often I bet you would spend more on ice or nearly the same on re-cooling chill packs. I just run my return through the chiller, I figured no reason to add another pump, and it's heat/electrical consumption.