menaus2's 240sqft Hydronic Thermal collector

[Daox]

What is your boiler pipe made of?

[menaus2]

Originally Posted by Daox

What is your boiler pipe made of?

The pipe is 2 runs of 1" Oxygen Barrier pex with 5 layers of bubble foil insulation wrapped around it. Its inside an 8" corrugated solid plastic drain pipe. I don't think "boiler pipe" is the right term but close enough!

Attached are some pictures of how the boiler pipe is roughly connected to the panel & the house. I had to get a little creative running the last bits above ground. Always room for improving the insulation. I used a scrap piece of 4" draintile to give it some protection. I'll find some way to hide it eventually.

One the pictures shows the temperature sensor. I placed it in the middle of the panel to run off the air temperature inside. I can always adjust the temperature delta from the controller. I think it's at 50F delta between the collector & tank for on and 40F for off. I used speaker wire pulled through the boiler pipe. The pipe had a plastic twine run through it when I bought it for pulling wires. Wire pulling lubricant really helped!

Getting closer!

[menaus2]

The battle station is armed and fully operational! Seriously though, I got the glazing on got water flowing the past few days and did a test run today since there were periods of clear sky.

I filled the reservoir with plain water & took a long time fiddling with it to get the water all the way through the loop & work out the bubbles. Like hours. I ended up using a shop vac of the outlet side to help it through. Had a section of pex I forgot to cinch. I think the real key was clearing out the bubbles in the short section of pipe before the pump so it could create enough pressure. No leaks that I could find. I'll have to keep an eye on the revevoir level for a while as I'm sure it will continue working out bubbles. I'll eventually add the glycol to the reservoir & dump the water as it comes out till it runs glycol. No big rush since it's for freeze Protection.

The glazing installation was easy. They fit right into place and connected to the next one with polycarbonate connectors over the 2x4 glazing supports. I used gray roofing screws every 2 ft horizontally and every 1ft vertically. I then sealed the edges on the outside with black silicone caulk.

Running it today a few take aways:

1.The temperature didn't get over 100f, the high sun angle and the big tree shading it don't help.

2. I think my vertical collector sees higher temps due to more air temperature stratification height. The horizontal shape seems to give lower temps but they don't swing as much.

3. I'm really impressed by the heat exhange to the tank. I adjusted the controller to turn the pump on with a delta T to 16f and worked fine compared to the other collector that had to have a delta T of 50f to work similarly. I got 14f tank temp increase over the day of 100 gal, so 11,662 btu.

4. I think the vertical, wide profile will really help with preventing stagnation in the summer. With that tree perhaps too well. It might have to be cut down & maybe some reflective material on the ground. I think in the Winter & lower sun angles it will be a real beast.

[menaus2]

Over the past couple of days the tank never really got above 80F. The sun angle is pretty high and the big tree by the panel was starting to block it especially around mid-day... so I cut it down in the morning. It was a clear cloudless day. The tank temperature started out at about 69F, by 6pm it was at 110F!!! This the hottest I've ever seen the tank and equates to 34,000 BTU. Excited to see what performance the rest of the year brings

[Daox]

Wow, quite the improvement. How big is the tank again?

[jeff5may]

If the tank is still the same, it's 100 gallons. Minus the heat exchanger circuit volumes.

[menaus2]

Yup.

Just and update of the performance. We've had a few nice sunny days with minimal clouds. The highest its gotten is 114F. The tank returns to about mid 60's to 70F after about a day or two since we have pretty high hot water usage.

I've been somewhat disappointed with the performance when the sun is so high in the sky. I must say the absorbers in the panel are very effective at cooling the panel. I had some scrap galvanized metal roofing laying around, so I'm working on turning them into simple reflectors in front of the panels. It should be simple to remove them if necessary.

[Daox]

Sounds like a nice idea to try.

[menaus2]

So its been about 3 months since my last update, and overall the collector has worked great over the summer and have made some refinements also.

1. The reflectors have really helped out with the high sun angle. 120f-130f for the tank an 150s for the collector are pretty common temps. I've recently gotten the tank above 140f recently even with hot water usage. I'll probably keep them on if they can survive the snow load.

2. My vertical smaller collector i just plugged in so it runs when the larger collector does. Simple & extra btus.

3. The system now runs on solar PV. I ran conduit from my small off grid solar system upstairs into the basement with its own dedicated gfci. I was using the PV system to run my satellite internet & office, but the battery is only 1 kwh. Not enough storage for cloudy days and a lot of power not getting used when sunny. The production and consumption is very well balanced and my battery is happier. The pumps take about 220w of power to run. The temp controller about 1-2w.

4. I checked out the tank with my SEEK thermal camera. The storage tank shows hardly any heat loss it works great. I did see a lot of heat loss through the pipes heating the storage tanks though even with the foam pipe insulation. I've started adding another layer of pipe insulation by using 2 sticks "clamshelled" around it and duct taped. Big improvement in heat loss and red green would be proud.

Before heating season I'm planning on:

1. Replacing the water circulation fluid with 10 gallons of glycol still stashed in the shed somewhere.

2. Pumps, piping & Contols to integrate the tank with my forced air furnace plenums. Really interested to see how it will work for space heating. I considered radiant heating, but its more than I want to take on right now. It would be pretty easy to modify it to radiant in the future.

[Daox]

Great update. I'm very glad to hear its working out well. I am interested to see how much heat you can get out of it in winter.