Single Barrel to be printed, with 2 separators going on the ends. Works with 2 120mm fans.

Inspiration from: https://www.youtube.com/watch?v=wJB3dyHDa-8

Works by transferring heat to incoming air from the outgoing air. Designed to use aluminum foil in specified slots. The design of slots could be optimized as I had difficulty putting in the aluminum.

The separator plate directs air through the barrel in alternating directions to promote the counter-current heat exchange.

replace half the aluminum with paper and it will facilitate some amount of moisture exchange.