|Testing Prototype Tube 1 in an East Facing Window|
|Off with their heads! |
(Also titled "going topless" but the wife vetoed that one)
So, I've decided to take the cans to the recycling bin and start checking out my options at the local home center. I also have thought a lot about the air flow issue. I had previously surmised that the baffling created by the small openings would slow the air flow and allow for more heat absorption. But as it is, Aluminum doesn't hold much heat being thin in the case of the cans. So slow air or fast air, my temperature measurements at the top of the stack were about the same. But with the baffles widened, and air flow increased, I at least could feel the flow of air with my fingers when testing prototype 2. So I concluded that what I really want is not resistance but length of run. The longer the run, the more surface area the air can exchange heat with and hopefully come out the top much warmer.
So, back to the drawing board. Instead of columns of cans, I plan a switchback path of tubing that will allow an always upward rise for the air but will provide one long run at high volume compared to 4 or 5 narrow, comparatively short, runs at negligible volume. Hopefully I'll have more to report later this summer as I'd like to have this done before next winter but summer activities will take precedence.