I have a problem. I live in the Midwest. (Har, har, har). Winters are brutal. At some point my garden hose feed will freeze and become unavailable for chilling, likely for the rest of the season.
But, I still want to brew outdoors. Gotta keep the pipeline full. I can take the cold, but I can't run my immersion or counterflow chillers without the hose.
So, I've come up with a plan. Patch my counterflow together with my immersion chiller and stick the immersion into a bucket of ice water. Will have to add an March pump inline to drive the circuit. Run hot water out of the top of the counterflow and through the immersion, while pumping cold water into the bottom end of the counterflow. Hot wort flows through the counterflow by gravity, ending up chilled in the fermenter.
Any thoughts? I have several concerns. One is the flow rate - will a March pump be fast enough to cool efficiently? Is the efficiency of a counterflow chiller dependent on coolant flow rate? Another issue is the immersion chiller length - I currently have 25 ft, but may have to lengthen it if I don't get a low enough temperature. Another concern is the coolant itself. I was thinking about using ethylene glycol as the coolant if water can't drain off enough heat. Poisonous ****, though - rather not have it near my wort if I can help it. Final concern - there will inevitable be some small amount air in the coolant line. I know March pumps die if they run dry, but can they handle a few bubbles?
Something like this might also help out those hippies who want to minimize water use.
Edit: I now realize that there are some other threads on this topic. My idea is not a beautiful or unique snowflake. Still interested in the efficiency, coolant, and bubble questions, though.