CBGjr

Thanks! I used TinkerCAD.

Thanks. I bought a Prusa MK2 and have been very happy with it. Saved some money, got it as a kit. Great vendor support and client community. Good upgrade cycle.

Looks great, always wanted to do something like this. Thanks for the great instructable!

Great job! I made a similar one with Plexi and fiberglass screening. https://www.instructables.com/id/Screened-Solar-Air-Heater/ Make sure you use a blower that can handle the static pressure or all the flow will escape out the back of the fan with very little actually moving through the system and pipes.

Hi Gordyh, I don't remember coming across builditsolar but I plan on spending some quality time with it now, thanks much! I had originally found this idea interesting and visited several websites and YouTube pots to see what people did with what they had laying around. When I finally decided to pull the trigger I just lumped together all of the bits and pieces that I thought worked the best for everyone else. I'm just finally getting around to hooking this unit up so I can start tracking how it works in the real world. I'll post updates as soon as it's operational.

Wow, I think I need to leave my other job behind. Thanks for the catch on the Sink vs Sync issue!! ;-)

Hi MatthewG80! Agreed completely but my particular installation had both the feed and return tubes going well below grade so there would be no natural flow. My thought was that by reversing the normal flow in the panel it would create "turbulence" and gain extra heat transfer. So, by blowing the hot air down through the naturally rising air eddies would swirl around thus increasing thermal transfer. Again, COMPLETE guess work on my part.

I've updated the post with some inside the hatch pics!

Hi Aussiejohnno, thanks for reading! This winter will be the first test and my fingers are crossed while my hopes are high. I believe last winter we saw the lowest temps drop to around -15c on and off but our normal lows hang around -10c. I'll keep everyone posted as to how it performs this winter. Danke!

Sorry, forgot to add. I also replaced the 12v PC fan with an honest to goodness inline 4" duct fan that will move a ton more air. I could run a simple thermal switch through the airflow tubing to kick the fan on and off but I love Arduino (and overly complicated things) so I'm going to throw in some sensors and timers to better move the air around.

Hi Poodle, thanks for the input on the thermal mass. I was hoping to balance out the highs and the lows and then "drain the tank" as the day ends to perhaps stretch out the cycle. Next test box will be without the thermal sync and I'll compare the performance of the two. No worries on covering any windows, this is getting piped in.. Your dusty screen comment was also spot on. I'm going to incorporate a pre-filter to help reduce buildup. Thanks!

Thanks Ariachus. I agree on the solar cells and using a simple, mechanical, thermostat to kick the fan on and off. The thermostat would allow the unit to come up to temp before blowing and cut off the fan before getting too cool. I actually have a few floating around in the parts pin. Set the screw for the right temp and never worry about them again. However, I really do like over complicated things. Nuff said.. ;-) If I have time before winter sets in I'd love to have two or three different models, each logging the data for comparison.