Ben's <$1000 solar hot water system
 

Hey Guys,

I have been collecting parts for some time for a (closed-loop glycol) solar hot water system.

As it is right now, I have a 4'x10' flat plate collector, 65 gallon rock-lined heat-exchanger storage tank, and 12VDC pump.

The tank is USED, in which I got the tank for "free" by trading the tank for my labor of removing it from the guy's basement. (I did NOT realize at the time I made the deal HOW HEAVY this thing is!)

Anyways, I might try to get the panel mounted in position (ground-mount, south-east corner of my house) while a person can still dig in the ground (winter's coming!)

But, I don't even know the condition of the tank yet, so... I thought I could start with pressure testing, just to make sure the tank didn't leak to start with.


On the domestic water side, the tank has 3 ports - one for cold water in, one for hot water out, and a temperature and pressure relief valve. I capped off the two side ports, to prepare to pressurize with air.

The idea of AIR pressurizing the tank is that you can test for leaks WITHOUT getting water all over. Air is light-weight, easy to work with, and all around us.

http://gallery.me.com/benhdvideoguy/...13185405040001

It also meant that I needed some way to get air into the tank. On car tires, the valve stem lets you put in air from a typical air compressor. I thought I would do the same on the water tank.

I went to the hardware store and got pipe adapters and a Schrader Valve - the same thing as a bicycle valve stem, only with pipe threads on it.

http://gallery.me.com/benhdvideoguy/...13185405800001
http://gallery.me.com/benhdvideoguy/...13185406050001

With the Schrader valve threaded in to the pipe adapters, it was now the right size to connect to the top of the heat exchanger tank, and add air. I just used my portable tire inflator, and pumped it up to 30 psi.

http://gallery.me.com/benhdvideoguy/...13185406350001

I checked the pressure, and marked it down, along with the time. I put the little plastic cap on the Schrader valve, and will let it sit overnight. Tomorrow, I'll check the pressure and see if it dropped any.

Already, I have run into one bump in the road... When I first saw the tank, it was still hooked up to plumbing. The guy who had it told me that he would have his son-in-law come over and disconnect it. After waiting all summer for that to happen, I finally got to go back to pick up the tank. Of course, the son-in-law just happened to CUT the connections off.

Instead of threaded ports, I just have two stubs of copper sticking out!

And here's the weird part - they don't seem to match typical American copper plumbing sizes. The wall of the pipe is extra thick, about 1/8", instead of the usual 1/16th. It's too big for 3/4" and too small for 1". The interior diameter of the pipe is just a hair larger than 3/4", and the outside diameter is about 1+1/16th". A coupler that would go over standard 1" is just a little too big.

http://gallery.me.com/benhdvideoguy/...13185405370001

When I looked INSIDE the two copper tubes, I CAN see that they aren't that long. They just seem to go through the foam insulation, at which point it connects to the inner wall of the tank (or at least the heat-exchanger part, I guess.) I wish I could get a photo of that, but it's hard enough just looking in there with a flashlight.

I really don't want to, but I suppose I could cut away the foam insulation to see what the copper goes back to. I don't know how the copper connects to the rest of the tank, but I can see from the inside that there is some type of connection.

The copper sticking out of the tank doesn't seem to be of any standard. I did stop at an HVAC place, to ask them (thinking maybe it was refridgeration copper?) and I got a few ideas, but nothing that has panned out. The HVAC guy also mentioned "swagging" a piece of copper pipe to fit over it, so I suppose that can be a possibility as well.

It's an American-made tank, and the other ports are standard 3/4".


Any suggestions?

Worse come to worse, have a machine shop turn down some thick wall pipe to make a coupler for a standard 3/4".

The solar tank is a 65 gallon blue FORD PRODUCTS CORP. tank.

I can't seem to find any information on them other than that they are out of business.

I'm starting to think something machined or modified is going to be the best way to go.

Tomorrow, I am going to see if I can find a pipe "swagger".

I think that if I just stretch out a 1" pipe, it will fit over the outside of the two cut pipe connections.

Daox suggested I might be able to thread the OUTSIDE of the existing stubs of pipe, and then thread on a standard connection.

Are you sure those aren't brass nipples?
http://www.hardwarestore.com/media/p...6_front200.jpg

Because, this is an iron nipple..
http://gallery.me.com/benhdvideoguy/...13185405040001

Those two little pipes just might screw right out..?.

The iron nipple, I added just to cap off the one whole.

I DON'T know that these AREN'T brass nipples, but I really don't have any great way to tell.

I talked to an HVAC guy, and he said that it was pretty common on tank construction to have some sort of short pipe go through the insulation layer and then connect to the heat exchanger. The problem is that you don't know what's on the other end. It could be welded, soldered, glued, etc, and may be connected in some other way than threaded!

I don't want to start destroying the insulation layer either.

Any way to figure out if it is a brass nipple OTHER than just cranking on it? If it WON'T thread right out, I might just wreck the whole tank that way!

You could probably take some scotch brite to it to clean it up and just look at the color.

Look at the specs on the NPT S40 3/4" nipples.
http://www.msi-products.com/Specs/Br...ples-Specs.pdf
Sounds very close to your mystery pipes..

Lift up that fiberglass and stick your finger in the hole and see if you can
feel any threads.. If it's a nipple, there will be a few showing..



Anyways, I wonder if you could turn-down 1/2" nipples (using a lathe)
so they would fit inside your pipes, for soldering??

The insulation is rigid foam, (like Great Stuff) not fiberglass, so I can't just pull it back.

The pipe is sort of "cast into" the foam insulation. So, I can't get to the other end of the pipe without cutting all that away. There isn't even a whole heck of a lot of room around the pipe before hitting the outside sheet metal cover of the tank either.

When I was talking on the phone last night with Doax, he mentioned that the size of the pipe seemed to measure up close to the outside of 3/4 NPT pipe. But I wasn't thinking about just a nipple threaded in there at the time.

I DID scrub up the cut pipes. While they had quite a bit of corrosion on them, and I thought they were copper.....

They did have a little bit of a gold tint to them. I held up some copper pipe that I quickly polished up to compare it with. Sure enough, much more gold colored by comparison. Here's a photo.

http://gallery.me.com/benhdvideoguy/...13186021500001

My digital still camera tends to exaggerate chromenance (intensity of color). In real life, there isn't such a huge difference in color between these two. With the corrosion on the pipe, it looked very coppery.

Since I had never heard of copper nipples, I never even thought of it!

So, if these ARE just brass nipples, what's next? SHOULD I try just unscrewing them?

What are the odds of the other ends being soldered or otherwise connected in there?

I don't think I'd try to unscrew it. If its not just screwed in you'll wreck something trying to get it out, especially with the tank being older you probably have some corrosion and/or build up over the years. I'd try to either thread the end or do you like you said and stretch a 1" copper pipe over the end and solder it on.

Mwaaa Ha Ha ha Ha aaa HHHaaa Ha ha!

The Gods of Plumbing smile upon me this day!

I started experimentally stabbing into the foam insulation. It really wasn't as far to go to hit the interior tank as I thought it would be.

The pipes are sort of off-center in the hole of the sheet metal cover. So, even though there was little room on one side of the pipe, it made more room on the other. I took advantage of that with a skinny chisel, and cut some foam out.

As Xringer said, sure enough, I could see some exterior threads on the other end. I also did NOT see any sign of solder/welder/weird gaskets/etc.

Time for the pipe wrench!

(Deep Breath!)

(And turn it....)

Yea! It unscrews!

On the port that the brass nipple went in to, it was just 3/4 female thread, then it shrank down to a smaller size (1/2"?) for what looks to be the actual heat exchanger tube.

http://gallery.me.com/benhdvideoguy/...13186039000001

On the second pipe, it was much tighter and more difficult to remove. Had I not already removed the first one, I wouldn't have tried any harder on the second one. I would have assumed I was screwing it up!

All I really needed was a longer handle for my pipe wrench!

http://gallery.me.com/benhdvideoguy/...13186039530001

Here's the two hunks of what I pulled out!

http://gallery.me.com/benhdvideoguy/...13186040050001

It all seems so simple now, but not knowing what was at the other end, realizing what the material was and NOT WANTING TO SCREW UP MY tank made this all very mysterious to start with.

I also noticed, after I polished up the cut pipe, that there were some indented lines running parallel to the length of the pipe.

http://gallery.me.com/benhdvideoguy/...13186039250001

I couldn't figure out what they were. Part of the manufacturing process?!?!? Oh well. After I used the pipe wrench to get the nipples OFF, I realized I just made MORE of the EXACT SAME MARKS! Those were marks from a pipe wrench when they put those nipples in!

Had I more experience with plumbing, I might have known that and realized right from the start that these were just threaded-in pipes!

Woo, I'm glad they just unscrewed! Glad to see you got it figured out.

Going to replace them with some pex adapter or what?

I think I will just replace those with new brass nipples.

That will get the pipe out to a working location, where I can then add whaterver else I need to.

I think I am going to start off by adding a boiler drain to the one right away. That will make it easier to connect a garden hose to flush out the system. At some point, I'll need a drain anyways, so I may as well get one right now.

Pipe wrench marks!
 

Nice! That shows the value of hi-res pictures. The first clue I saw in your first pics,
http://gallery.me.com/benhdvideoguy/...C_9865/web.jpg
was a tiny line on top of each pipe. But, it was hard to see if there was more.
I wasn't 100% sure, but the spec was another good clue.
That's why I asked you to dig in and look for the threads..

I've used a few 1/2" brass nipples and I always mark them up pretty badly.. :p

Have you decided what plumbing you're going to use from the tank to the collector yet?

Well, PEX is cheap.

I've heard mixed horror stories though. Some people say how solar can get rediculously hot and melt through anything. Other people say that the hot water PEX works great, and why spend any more money on copper.

I need 25-30 feet each way between the collector and the solar tank, which will be in my utility room in the middle of the house. (No basement!)

1/2" soft copper is about $120. 3/4" is $180. I could buy a lot of connectors, valves, etc for that money.

I'm thinking of using PEX instead of copper if nobody has any objection.

Either way, I do want to use flexible material. It will make it a lot easier to work in my crawlspace that way. It's kinda hard to solder straight copper laying on my back in the dark!

Yeah, copper is really expensive unfortunately. I just looked it up, 100ft of 1/2" pex (I don't think you'd need 3/4" for your one fairly large panel) is a whopping ~$25. For that price I think its worth the risk of it bursting just to give it a shot.

What are you thinking about doing for insulating the lines?

I picked up some new brass at the home improvement store.

Two nipples and two boiler drains. I figured that I needed to use garden hose to flush and drain the tank, and the boiler drain has garden hose threads right on it.

Here's the new brass fitted to the tank.

http://gallery.me.com/benhdvideoguy/...13186202300001

I then connected up my garden hose (Actually, a fancy double-ended hose, as it's going from one spigot to another.) The other hose was draining out onto the lawn.

I did this for a few minutes just to flush everything out, and make sure there weren't any major leaks or screw-ups.

http://gallery.me.com/benhdvideoguy/...13186202390001

After that, I connected the hoses to a Harbor Freight stainless steel 12VDC water pump.
http://gallery.me.com/benhdvideoguy/...13186202440001

This is more or less what my final system will be. The sections of garden hose were even roughly the distance from where my panel to my tank will be.

I had two 5-gallon buckets. But checking to see how long it would take to fill one from the other, I could determine my flow rate.
http://gallery.me.com/benhdvideoguy/...13186202560001
http://gallery.me.com/benhdvideoguy/...13186202630001

It took 4 minutes to fill a 5-gallon bucket. That's a flow rate of 1.25 gallons per minute. I'm shooting for anywhere between 1 and 3 GPM. It's on the low end, but ok.

The "sucking" hose is squeezed down a bit from the pump pulling on it, so I think that's hurting the flow rate just a tad. Rigid pipe would fix that.

With a closed loop system I'd aim for the upper end of the spectrum if you can easily enough find a pump that gets you there. From reviews I've read, people have said you can't run that harbor freight pump continuously. You probably know that already though. What about the computer pump that Gary used on his domestic hot water loop? Its pretty inexpensive and has worked out well for him. Here they are: Swiftech - Pumps

Newegg.com has better prices on them.

I even have one hanging around if you'd like to try it out.

Right, the Harbor Freight pump was just for doing a little testing.

I have a very nice pump already, but it doesn't have those handy garden hose connectors like the Harbor Freight pump does.

The pump that I do have is called an El-Cid, and is designed for 12V solar. It's also a REALLY simple pump, so less possible future maintenance.

The downside to it is that it is NOT a high-head pump. It needs to run a pressurized system so that the weight of the liquid going out equals what's coming in, so it's not doing any of the heavy lifting.

I'll need a set of fill/service valves before I would be able to use that pump, as you need to be able to pressurize the line with the pump already in place.

I've seen a solar system charged with fluid before, and know I need to be able to do the same thing. In fact, I am the guy who shot and edited this video - Watch Bob "Hot Rod" Rohr Install a Caleffi Solar Thermal System - YouTube

This one is actually a "cut-down" version of the video they have to train installers. The full video is about 45 minutes or so, and includes filling the system.

Is your el cid going to have enough flow for your large panel?

It's supposed to be able to do up to 3.5 gpm, but I want to get it hooked up in real-world test conditions.

How do you plan on testing the flow rate of a closed loop system?

Well, I don't have the right parts to do that right now.

I thought I would sit down and figure out what valves, drains, etc. I would need for charging the system. Then I would thread/solder them all together, and mount them on a hunk of plywood or something else that I could mount up later for the finished system.

I would then just have the pump hooked up to the "solar in/solar out" of the tank, and pressurize the system using the the Harbor Freight pump and water.

Then I...... Doh!
I see what you are saying. I really need to dig up a flow measurement device, as I can no longer use a bucket and stopwatch.

I thought I would find the original version of that solar instal video and go through the system charging part, so I could remember all the components that are built together in their kit for charging the system.

Did you get your pressure test sorted out?

I pressure-tested the "tank half" by adding pipe caps to two of the connectors, and a Schrader valve (tire stem) to the third.

I then pumped up the tank with an air compressor, and checked the pressure. The next day when I checked it, there was only about half as much pressure. It lost quite a bit over night.

I'm not sure if that's because of a leak in the tank, or if I just did a bad job with the pipe tape, and screwing all the connectors together. I think it may be the later. I did need several adapters to get from the 3/4" pipe to the air valve, so there's several places I could have just not gotten everything to seal exactly right.

Today, I put the Schrader valve on the heat exchanger side of the tank. I already had a boiler valve on the one end, so I just closed it. The other end of the pipe already had the right size adapter to thread the air valve right in.

I again pressurized it with my portable tire inflator. Much quicker to pump up this time. The tank is 65 gallons. That took a while to put air in there. (Ever pump up a 65 gallon tire!?) The heat exchanger filled with compressed air very quickly. I checked the pressure, and then rechecked it six hours later. It read the same pressure.

The fun part was that just by opening the boiler valve, I could let all the air out real fast! WHOOOOOOOSHSSSSHSHHSHSHHHH!

http://gallery.me.com/benhdvideoguy/...13194174310001

I removed the 4'x10' solar collector from its wooden frame. That way, I could simply place the frame in front of the house where I plan to install it. I used the tape measure and made a diagram, but sometimes it's just so much easier to just DO something and see how it looks!

I raked the leaves away from the house, so that I could more easily use spray paint to mark the ground. Here, you can see the south end of the house, with the wood frame plopped down roughly where it will go.

http://gallery.me.com/benhdvideoguy/...13194175130001

The frame is a bit smaller than the solar panel. Basically, the frame is about 8' and the panel is 10'. It sticks out a foot on either end. I think that's just because 2x4s come 8' long as a standard. The tape measure behind the wood frame is pulled out to 10' to help you visualize the size of the solar panel.

http://gallery.me.com/benhdvideoguy/...13194175300001

I leveled the frame as best I could, with two hunks of firewood. The ground slopes away from the house, but I want to make sure the frame is nice and level. I plan to mount the frame on four 4x4" posts sunk in to the ground. I don't think they will be cemented, rather I will dig holes, fill the bottom of each hole with at least 6" of gravel, add the posts, and then surround them with gravel and pack it down. Once the posts are in the ground, I will cut the tops of them to be level with each other. I plan to leave the posts 18"-24" above the ground. That way, the entire solar collector will be elevated, to keep it up out of the snow.

I also went down into my crawl-space. Mine is cement floor, and cinder-block walls, typical of most basements in our area. The only difference is that my basement is only 20" deep. I keep a mechanics creeper down there so that I can roll around on my back whenever I need to do something down there. (Sorry, no photos, it's dark and disorienting down there anyways!)
The exposed cement block walls down there are two-and-one-half blocks tall. Seeing as how cinder blocks are 8" tall, I think that means that there are really three rows of block, but the bottom block is partly covered by a 4" cement slab.

I'm not sure exactly how far down to knock the hole in the cement block. I'd like it to be underground, to visually hide where the pipe penetrates the house. (This IS the FRONT side of the house, just so you know!) Looking at how a typical cement block is made, it has two hollow cavities in it, side by side. I figure I need to knock a hole through the center-left or the center-right of a block. If I do that in the middle row of block, that's only 12" down from the bottom of my floor. (8" block, plus one half of an 8" block, 4" = 12")

If I drill into the bottom-most layer of block, the one half covered by the slab, I may be close enough to the floor, that the floor interfere's with the handle of the hammer-drill. Also, I really want to put a 4" PVC pipe through the block to act as a conduit and cover for the solar fluid pipes. Those two pipes are about 2" in diameter, each, once they have good insulation on them. The 4" PVC pipe is what will be cemented into the wall. It will extend out of doors (hopefully mostly buried!) and protect the pipe insulation outside from sun, weather, and animals.

I was also originally going to have the house penetration at the left-most end of the solar panel. (The cold water inlet to the panel is at the bottom left-of the panel as you look at it.) But after thinking some more about it, that may leave some PVC pipe as an ugly visual. I think I would rather have the 4" PVC pipe come out BEHIND the solar panel. From there, the two 1/2 pipes to and from the collector would split up and go to either end.

I also wasn't sure how far away from the house I wanted the collector. Ideally, I would like it as close to the house as possible, just to look nice. However, there is a window planter box right there as well. With the height of the collector, plus the 4x4 posts to get it up out of the snow, it looked like the solar panel would cover the window box.

When my wife came outside to see where I was planning to put the solar collector, she said "Why don't you just move the window box to the other window?". Sure enough, the other window doesn't have a window box. Never has. The one weekend I was out of town, and my Dad snuck over to build window boxes, he ran out of cedar. All the windows down the other side of the house have boxes, as does the right one, but the left one doesn't. If I just move that box to the other window, I can have the solar panel closer to the house, and everything should look nice.

http://gallery.me.com/benhdvideoguy/...13194175370001

To get the solar panel nice and close to the house, the two post holes closest to the house need to be 12" from it. I'll have to take a look at the tool rental place to see how big the handles and things on post-hole digging machines are. I need to know that I can did those holes that close to the house.

The other thing I still don't know, is how far I need to go down before I hit water. We live down the street from the lake. It's a few blocks away, but not much lower than us. I also have spring in my front yard, just off the road.
When I dig down, who knows what I will hit!!?!?

(Although from inside the crawl-space, I did confirm that there is no electric, water, or gas pipes coming through the south foundation wall. Gas pipe is on the west side of the house. Well is on the east, and the electric box is on the north-west corner.)

Too bad those blocks are so hard to drill. When I want to install something outside
the house that requires a hole-in-the-house, I always drill a small test hole.
One that I can patch up, if it turns out to be a bad spot..
For thick walls, I use a steel rod (Music wire?) with a flatted and sharpened end, as a long drill bit.

Maybe you could use small masonry bit to probe for the cavities inside the blocks.?.

1/4 In. x 13 In. Double Flute Masonry Bit-14044 at The Home Depot

A few 1/4" holes wouldn't be too hard to patch up.. :)

For digging the post holes, you can just get as close as you can with the powered digger and then just use a manual post hole digger to 'slot' the hole a bit. We had to do this with my 3 middle posts on my solar rack. You can never get the post holes centered perfectly between the outmost two of them. Its not too much work to enlarge the hole once its dug.

It looks like the tool rental places have post-hole drillers that come standard with a 6" bit. They also have 8" and 12" available at extra rental fee (but it's only like $5....)

I read on one web page about setting posts that you want a hole THREE times the diameter of the post. I guess that gives you the same amount of fill on either side of the post as the post is across.

Today is sunny, even though I have other things to do, I'd like to get a little something done on the solar system.

I think thats the rule when you're putting something large up into the air. However, for your relatively short ground mount you could probably get away with an 8" auger which will make a slightly larger hole.

I've done a little work here and there the last couple days.

http://gallery.me.com/benhdvideoguy/...13195502690001

To start with, I planned to dig a test hole. I was talking with my Dad on the phone, and he said that I really didn't know what I was going to hit when I started digging. Which is true. I have really high ground water, and very unusual soils that all meet in my yard.

If anyone is familiar with Wisconsin geology, you might be aware of how the glaciers of the last ice age define our modern landscape. Well, the glacier stopped in my yard. Seriously.... I talked with a university geologist once.

Anyways, that darn glacier means my yard varies from gravel to clay to, and I am not making this up, "glacial ooze". (That's actually the scientifically correct term!)

So, I borrowed a hand post hole digger and a long digging bar and set to work to dig a hole 6" in diameter, and as deep as I could get it.

I dug down 12" before I hit the first road-block - a 4" diameter root - exactly across the dead center of my hole. I moved over 3", and started digging down again. I made it to 32" before I hit water.

In my area, what you always hear about footings, foundations, and digging holes that will survive the winter is "dig down four feet". Well, that's not really an option here. It doesn't make sense to dig deep enough to put my 4x4 post into water, just to let it rot.

http://gallery.me.com/benhdvideoguy/...13195502770001

My thought was that I would leave the hole overnight, and see how much more water seeps in. In the mean time, I decided to start digging the other holes. Since I now knew I wouldn't be going that deep, I would just dig them by hand, no tool rental needed.

I dug holes where two of the other posts will go, but was able to dig just a tad deeper than the first hole. Then it got dark, so I'd have to wait to do that last post hole.

The next day, I could see that the test hole had filled in a bit with water. My plan at this point was to fill in the bottom of the hole with gravel to get above the water line, then put the post on top of that and fill around it with gravel and stamp that down.

Later in the day it rained, and has been wet weather since then. My holes now only have 18" from the ground level to the water line.

I also borrowed a hammer-drill and 14" long masonry bit. Crawling to the deep underbelly of my house, I measured 6' from the end of the foundation, and started drilling holes through the cinder blocks, as close as I could to the concrete floor. The idea there being that on the south side of the house, there's lots of exposed foundation. I wanted to get my solar pipes buried underground if possible.

Outside, I dug a couple of shovels full away from the foundation. While drilling from the inside, when I did put the bit all the way through, I did see daylight. Yea! I measured correctly!

I drilled a series of holes and then started smacking the concrete with a chisel and hammer, to break pieces away.

http://gallery.me.com/benhdvideoguy/...13196363090001

By now, it was dark. I still didn't have a finished hole yet, but the wife frowns on using hammer drills directly under the nursery after the baby's bed-time! :(

So, right now, I have three gopher holes in the ground, half filled with water, and a hole in the side of my house. I stuffed some foam into the hole in the foundation, just to keep the cold and the wind out, and maybe even animals...

I WAS planning to put a 4" PVC pipe through the foundation. It would act as a conduit for the plumbing, pump power wires, and thermal reading wires. Foundation cinder blocks are 8"x8"x16", the but hollows in the middle of them are NOT 4", they are curved and end up being a bit smaller than that.

Also, when I was out and about yesterday, I stopped at the building supply store and picked up just a few "test sample" pieces of plumbing and insulation. Here's two photos of 1/2 pipe with closed-cell foam rubber insulation over the top of it. Two of these side-by-side come to about 3" across. (One send line, one return line.)

http://gallery.me.com/benhdvideoguy/...13196364750001

http://gallery.me.com/benhdvideoguy/...13196364770001

That foam rubber insulation is pretty nice. It's marked as "UV-Resistant" and is self-sealing along the slit AND has a self-sealing flap that folds over the top of the seam as well. I'm not sure how much better the R-value is on this stuff compared to the plain, cheap pipe insulation, but it sure seals up nice!

I know that any exposed pipe insulation outdoors needs to be protected from both sun and animals. Part of it should be protected by the 4" PVC, but I'm not exactly sure what to do for the individual pipes going to the two far ends of the panel.

Going back to that hole in my foundation. Maybe I can find some 3" PVC that will fit in there. Otherwise, making a 4" hole in there may be challenging. We'll see. I need some better weather and time during daylight hours to keep working on it.

If you're worried about rotting wood, it was suggested to me to put metal in the concrete and then bolt wood to that bracket. That keeps the wood out of the the ground and away from the water.

Nice update!

Wood keeps it all simpler though.

I need to make everything 18" - 24" inches above ground, just to make room for winter snow (including the EXTRA that slides off the panel.)

By using wood posts, I can leave them extra-long, then cut them off level with each other. With any concrete work, I now need to make concrete posts AND still have wooden posts coming off of that. At that point, I would also need cross-bracing, etc. Seems like it starts getting a bit complicated.

I mean just pour the concrete in the ground and put the bracket on top then bolt the wood to that. You don't need a concrete post sticking out of the ground or anything. Xringer posted this image in my solar hot water thread. This type of bracket simply lifts your wood a little bit off the ground away from moisture. You could still mount the posts and cut them to even heights and I don't think you'd need cross bracing.

http://www.homehardware.ca/products/300/26497451.jpg

Oh yeah, THOSE brackety things.

Would that give much advantage over just having gravel in the bottom of the hole?

The gravel would get the post above the water line AND allow water to drain away.

Concrete will always absorb moisture and keep your wood damp. Having it out of the ground is most ideal. I wanted to do this but convenience got in my way. I'm sure its not a huge deal either way, just throwing out the option.

bennelson,

Sounds to me like you have some real potential for GSHP action.

Wet dirt has really good thermal transfer potential.

How deep is the frost line where you live?

-AC_Hacker

Ben, I know what you mean about WI ground. We live in a flood plain and the year we built our house we hit water at just 12" down. Also have clay, dirt, gravel, clay, gravel, etc...:eek:

I've also been planning to put up some hot water solar panels on a ground mount system but the area where I'd like to put it has our Geo lines running right under there. :(

So I've been thinking about a different approach which may work for you as well. Unless someone can give me reasons why it wouldn't work.

Instead of digging holes and putting down post and supports. Why not just pour a concrete pad?
Just dig down 8" to level it out and put down some gravel base and pour a top pad. It should have enough weight as to hinder any wind resistance.
You could also sink in some bolts or those post adapters shown earlier right in during the pour.
Only downside I can think of is that it might be more expensive but hopefully by not too much.

This is one reason we put in the Geo, our ground is always wet which should be more efficient.

Around here the frost line is 42" from what I've read but everyone says to go 4'.