Desigining & building a solar hot water panel rack

[greif]

I have a 600 gallon tank for storage and installed under floor heating. Works pretty good. We have a big house so doesn't heat completely but does good. And keeps the pool warm in the summer

[ecomodded]

This is a great thread, now comes the juicy stuff,the panels being constructed the inside exchange system.
Will it be heating the floors or the house by a radiator, also how will you heat the household hot water ?

I have plans to live off the grid in the not so distant future so this hot water system will be excellent to learn about. I also want to design a kick *** hot air system with a large rock filled heavily insulated cement covered oven to store heat in.
I am planning on using non combustible materials as i am hoping to get the system that hot, possibly, it would be nice.

I still have not determined how hot these systems can get, Large scale closed loop systems use a gas instead of air and get to 1000 to 3000 degrees or some such incredible heat.
What i would do is keep circulating the hot air threw the rock heat storage all summer, collecting and storing the heat for later use.
The bigger the storage the longer the reserve heating.
They have systems now that store the heat for a year,mind you it's at 1000's of degrees.

[Daox]

I currently have hydronic floor heating in one room in my house. I am renovating another room right now and it will have hydronic floors added and I'll continue renovations and adding the hydronic floors.

The problems with high heat systems is high energy loss (lower efficiency). If you can keep the heat lower you can gain a lot more with less panel area. That is actually one reason why hydronic flooring is so great. Properly designed, you can get away with using much cooler water than a radiator would need to heat the same area.

[Daox]

Well its a rainy weekend here. I was planning on prepping the trench a bit more and finishing up the last bits of digging, but that probably won't be doable until this coming week once things dry out a little bit.

In the mean time, I've received my pex tubing and the pump for the system along with most of the fittings I thought I might need.

With the bad weather keeping me out of the trench, I figured I would work on getting the insulation ready for it. I am insulating the pex tubing with 3 inches of extruded polystyrene insulation, good for a total R value of 15. This is far more insulation than I've seen from any commercial underground tubing solution I've seen, and its also far cheaper. Of course, its also a lot more work!

I'm starting this with 8 4'x8' sheets of xps that are 1.5" thick. I wanted to buy 3" thick pieces but they were not stocked and I had a vehicle to transport them for only one day. This means I'm going to have to glue a bunch of pieces together to get the required thickness. Below shows the cross section of what I'll be assembling. The tubing will be run in the two voids in the center.




To assemble the foam I'll be scoring/cutting it with a knife and straight edge / square, and then breaking it. Then, it will be glued together with PL300 construction adhesive specifically meant for foam. I was told regular construction adhesive will eat the foam.

Pictures to come soon.

[S-F]

To glue the foam you can also use PUR Stick in your foam gun. That's what I always use to glue EPS/XPS. You may also want to consider using a table and or circular saw to cut the foam. It cuts straight and breaking it can get messy and slow. The rough edges are impossible to fit snugly together. You'd use a truck load of glue trying to seal it all up.

Good luck!

[Daox]

Interesting product. I'll have to check it out. How does it differ from a solid glue? I didn't pick up too much PL300 adhesive, so I'll look into it when I run out of it.

I agree that scoring/cutting is more work. It doesn't seem to be too messy though. There are some flakes, but a quick vacuum job will sort that out pretty quick. Is a saw really cleaner to use?

Thankfully, the faces that are being glued together aren't the ones being cut, so it should work out.

[S-F]

The cuts are cleaner. Probably doesn't matter if you aren't attaching the cut ends. But it is MUCH faster. It is a bit messy. Just do it on a big tarp. It isn't dusty so unless it's really windy the fuzz won't really go anywhere. I've heard of tube foam glue but never used it. I actually don't know any one who has. I'm sure it works but it would be slow and a pita to apply. And I KNOW PUR Stick lasts for several years at least when underground. It's what everyone I've ever heard of is using for gluing EPS and XPS together when buried.

[Daox]

I got most of the cutting done this weekend. No gluing done yet.

I started with 8 4x8 sheets of 1.5" thick XPS insulation board.





Here is how I cut it up. I marked each board out, then used the square to guide the blade as I made the score marks. For the thinner pieces I needed to cut, the 3in and 1in pieces I did cut almost completely through the board so it wouldn't break.






All the 9.5" wide pieces cut up from one sheet.






Here is the current stack of foam in my yet un-remodeled office.

[Daox]

I wanted to do this a couple days ago when I got the PEX, but it was raining all weekend. Tonight I uncoiled the PEX tubing out in my back yard. With it being 51F outside, the PEX is a bit stiff. I had hoped to do this while it was warmer out so I had the heat and sun to help me coax the PEX into a straight line. So, it'll sit outside for a few days while it straightens out.

[ecomodded]

If the weather does not improve you could run hot water threw it.
That is some nice flat property.