menaus2's 240sqft Hydronic Thermal collector

[menaus2]

The world slows down, but construction continues! Framing has been completed. The shed wall isn't exactly plumb, but it's level. Good enough! I siliconed (black silicone) the wood to keep moisture out on back side. Next is the 1" polyiso board (staggered). Then pine 3/4"x 1.5"s to finish the glazing support. Glazing support is set back 1/2" to allow the polycarbonate to be siliconed on the outside. I put 2" strips of polyiso on the inside edge of the frame to finish up the insulation. Currently working on putting up the 1/2" OSB panels over the polyiso. All the piping/ collector fins will be eventually stapled to the OSB.

The underground insulated pex I got is the reflexive bubble wrap inside of drain tile style. Some online sources point out they can lose a ton of heat if water gets into the pipe. Does anyone have experience with wood boiler pipe like this? I was thinking I might install sock drain tile pipe beneath it just incase the pipe ever got punctured to keep it dry enough. Possibly a drain hole at the low point of the underground boiler pipe just to give the water an escape route in case water ever did get in?

[menaus2]

Had nice weather yesterday before rain moved in, so prioritized making sure the OSB was protected enough since it shouldn't get wet & I don't have plastic laying around. Sealed up all the seams with silicone & painted over with flat black spray paint.

For additional protection, I used aluminum facia trim for a roof. Scrap block pieces from the glazing support gave it a little pitch. Screwed it down with roofing screws that were laying around. When things dry up, installing the pex-al-pex pipe & absorber fins will be next.

Also, looking at the actual dimensions & depending how I do the glazing the collector area is looking more like 118-125 square feet.

[menaus2]

Construction continues into the slow tedious phase of collector pipe and aluminum absorbers. For the back of the absorber I stapled up 3" wide strips of aluminum coilstock. Not sure on the thickness, but good enough I suppose. 8 strips by about 56 feet so about 112 sqft of material.

I'm currently in the middle of stamping out the absorber find & installing them. Helps break up the monotony of either task . The front absorber plates are cut with power shears into 6" x 24" blanks. Then my sophisticated stamping process consisting of a wooden form, 5/8" steel rod, junk boards, mallet and a post pounder. With ever 200 to make total, needless to say it will take a while.

But when the weather is nice, I can install the absorbers. The pex-al-pex doesn't need a perfect level, just a few beads of silicone for good contact & some narrow crown staples does the trick. Just a matter of time, since this is probably the single most time consuming step of construction.

[Daox]

Its coming along great!

How much work is it to stamp out those heat spreaders?

[pinballlooking]

Great progress.

[menaus2]

Originally Posted by Daox

Its coming along great!

How much work is it to stamp out those heat spreaders?

Thank you for the kind words. Yes, it's a good amount of work with over 200 to stamp out. After a while you figure out the "technique" and easier when you get the post pounder to bounce a bit.

[menaus2]

Absorber fin installation continues! A little over halfway done. I've spray painted completed sections to get an idea what it'll look like finished (as well as a motivation boost!) Straightening out the pex-al-pex takes time and patience. I'm doing my best to keep them equal lengths so the flow is balanced between the 4 separate runs. It sure takes a lot of silicone!

[menaus2]

Absorber fins and painting are done! I did my best to make everything an equal length, but I'm sure each run will be off a bit.

Does anyone have an idea how much difference in flow there might be between the 4 loops or how much this could impact performance? Say if there were 6-9" differences in loop lengths? Extra valves & gauges to balance things perfectly could add up. Maybe adding ball valves & use an IR camera with glazing off to see imbalances? I'm guessing higher flow in one loop would show up cooler than the others?

Anyways, the next step is digging a trench for the piping. I will be laying draintile underneath the wrap style insulated pipe to protect it from getting water inside of it. It will have the added benefit of keeping the yard & basement a little dryer!

[Daox]

It looks like your setup is roughly 62 feet (750 inches) long? So, plus or minus 9 inches isn't going to matter much at all. 9/750 = .012, so 1% flow difference. Not worth any worry.


It look awesome by the way!

[menaus2]

Originally Posted by Daox

It looks like your setup is roughly 62 feet (750 inches) long? So, plus or minus 9 inches isn't going to matter much at all. 9/750 = .012, so 1% flow difference. Not worth any worry.


It look awesome by the way!

Whew! Thanks for the info!

Since my last post, I've gotten the underground pipe in (mostly). It was easily a week of digging and probably the hardest part of the whole project so far since it was mostly done with just a shovel. Rocks are not fun!

Basically I dug down 28"-30" made sure everything had a slight slope with a level. I then laid landscape fabric along the bottom of the trench. Over the fabric I laid about 1" layer of washed river rock. Over that base layer of rock I laid a 4" socked perforated corrugated pipe. Then filled the pipe up to its top with more river rock. The extra landscape fabric in the trench folded over the top over the rock & pipe like a big ol' burrito.

Theeeeen, my corrugated underground boiler pipe laid over the drain pipe and I buried by a few inches with some of the nicer soil. I put some strips of 250 psi XPS polyiso over that. I figured it would add some insulation & strength to protect the boiler pipe. The rest of the trench I could backfill with rockier and rougher soil.

At the lowest part of the boiler pipe before it pokes up near the house, I put a bunch of holes in the outside of it in a 1-2 foot section. That style of boiler pipe is basically useless if it fills with water. By keeping the surround soil dry with the drainage below it, then sloping it to a drained low point, it should allow any water that eventually works it's way in to be naturally drained through those holes. Boy I really hope it does, because it was a lot of work to dig it up again! In retrospect, I would've gone with thermopex.

What remains:
1. Hooking up pipes & run sensor wires
2. Run pump & check for leaks
3. Wiring controls
4. Attach glazing
5. The separate pump & controls for the furnace heat exchanger (less important as we're coming out of the heating season).
6. Make things pretty, maybe cut down a few trees if they block the panel too much.