Used solar hot water panels ,

[jarrod9155]

   I had just begone to build some diy panels for heating water and I found some 4 by 8 feet panels the guy has 12 of theses they are about 14 years old  been seating for 5 years not used. I bought 3 of them for 150.00 $ I then took them home and removed the glass and took the sides apart that were alumiun . The collectors are all copper the manifold s are 3/4 and the risers are 1/4 there are 14 of them and the fins are solder to a big sheet of then copper the complete size of the collector. So far no damage to the copper but the insulation under the copper is molded and shot the glass is ok but the glass has a strange grid pattern on the inside i was told for light refraction or to direct the sun inside even at a angle . I would like to replace the fibberglass insulatiion with foam board about 2 inch thick any ideas . I would like to go buy three more . 

[TomW]

Depending on the type of foam it might melt from the temperatures it will see.

Sounds like a true score to me. Likely worth the cost for the metal value in copper sheet / tube.

My first idea, sight unseen, would be loose fill fiberglass to replace the moldy insulation.

I am sure foam board exists that can handle high temperatures but the common bead board or pink building foam may not.

Good luck with it.

Might ask if he has any of the pumps / controllers or what not

Right up against 400 square feet of collector with all 12 sounds like enough panels to heat a small house in sunny winter weather. Something like 40+KW of heat available in that collector area??

I would be on them like white on rice myself.

Tom

[jarrod9155]

This is for sure all new to me solar hot water heating im glad it seems to be a good deal he has 9 panels left so i will go back and get three more plus he had a 3/4 copper spoil about 20 to 30 feet all set in a jig that keep it coiled for a heat exchanger for 60.00 bucks .
       I plan on making this a drain back setup i dont care for antifreeze setup . If i hook theese panels up what would be the ideal way . The panels have 2 outlets top and bottom so would I feed into the bottom and return out of the top . The panels are going to be on the roof with 6 /12 pitch not a crazy pitch with all the plumbing 3/4 down to tub or storage 20 feet below in the basement . Thanks Jarrod

[jarrod9155]

Could I get away with using pink r 13 for new insulation could it take the the heat  . The panels had a yellow type insulation in them that had to be remove .

[B529]

Have you pressure tested them? I would not do anything to them until they passed that test. What brand are they?

Call these guys to get advice on your insulation, they been doing hot water for many yrs.  http://www.aaasolar.com/ Lots of good info on their site, design....

I put together a closed-loop DHW system with used panels, bought several small things from them that were hard to find locally.

The glass on my used Novan panels have that same grid-like appearance.

The 6/12 pitch roof will be fun

[Tom Sullivan]

The pink fiberglass insulation will probably work, but this type of insulation is very prone to absorbing moisture.  A lot of panels today are using polyisocryanate (Styrofoam with the foil facing), which has a pretty high temperature rating and is resistant to moisture.

As far as return line location on the panels, it sounds like you will need to run external manifolds for both your supply and return to accommodate your drain back function.

A tip on collector tilt, you should assess what season of the year you desire the most efficiency from the array.  A lower angle will generate highest efficiency in the summer, while an angle closer to 70-80 degrees will produce more heat in the winter.  A lot of us solar hot water users keep the collector tilt steep (nearly vertical) to maximize winter heat collection.

My website shows a lot of different recently completed systems; 90% of the material on the site is dedicated to projects and is informational in nature.  www.aluminum-solar-absorbers.com       You should find some information of value there.

As the other Tom alluded to, the collectors you found sound like a no brainer to purchase.

Tom Sullivan

[jarrod9155]

The panels are made by Elbert mfg in millbury, Mass . The back is fiberglass sides are allumiun and top glass with  full copper collector . Thanks for ideas guys .

[jarrod9155]

Ant ideas on the best pump for my system
Details
20 to 25 feet head pressure
5 panels with 3/4 manifolds and 3/8 risers
supply line to panels is 3/4 inch pex , drain back system
       Hope this is enough info for a pump I was looking at a taco 009 pump didnt like the watts it draws but that might be the price to pay for a tall head pressure . Any ideas or suggestions would be great just dont wont to get the wrong one .

[jarrod9155]

I went with some of that foam board with alumiun face made buy dow polyisocryanate (Styrofoam with the foil facing , Home depot 17.95 a board 1 inch thick and then used expanding foam along the edges . And the pressure test was good .Also did a binch test in the sun and it  worked great .

[Tom Sullivan]

Jarrod,

Gary Reysa has a great article on flow rates and pump sizing (link below).  Taco also has a chart on their website that shows the flow rates and head limits to their pumps.

http://www.builditsolar.com/References/ColFlowRate.htm

I will note, though I've used exclusively Taco on my projects, many builders are now using the Grundfos 3 speed pumps.  Once you get out of the "common" pumps in Taco, with higher flow rates or head capability, the Grundfos seem to be more reasonably priced.

Tom Sullivan

Ant ideas on the best pump for my system
Details
20 to 25 feet head pressure
5 panels with 3/4 manifolds and 3/8 risers
supply line to panels is 3/4 inch pex , drain back system
       Hope this is enough info for a pump I was looking at a taco 009 pump didnt like the watts it draws but that might be the price to pay for a tall head pressure . Any ideas or suggestions would be great just dont wont to get the wrong one .

[jarrod9155]

just a quick update got one more panel making it 4 panels now plus I got a 3/4 copper coil that is pre wound in a 2 by 1 foot coils about 11 coil high . Should make a great heat exchanger in a tank . Not totally sure on how many gallons , maybe 300 to 500 gallons . And I will go with a taco pump 009 ebay pretty good prices there . So far I am only in to this project 330 dollars 4 collectors and a big copper coil  , nothing like the money invested in the wind mill project . 

[Fat Charlie]

That's a green project all right.  It's making me quite green. 

It's one hell of a score.

What general region is this guy in?  I'm sure anyone here who's nearby would be happy to buy what's left once you're done.

[jarrod9155]

Today I took the one panel I have finished and hook it up to my sons 50 galloon pool that was cold and within a couple hours it was warm for me this is new and really cool to see this work my son loved it to . I sent the guy a  photo of the finished panel and he wants me to restore 4 of them for him and he will give me 4 complete panels 2 that are missing glass  plus 280 cash that will make 8 panel system  . So now there isnt any left just 2 without glass that I will keep for back ups .The guy  I bought the panel off of was worried the foam with aluinium  or polyisocryanate would out gas and film up the glass under real hot coditions any ideas of this out there .

[Tom Sullivan]

   I have the polyiso on my panels and saw my highest tank temps today since going live 8 months ago; 170 degrees.  Actually too hot, really.  No problems with the polyiso on the big array.  I stagnated a glass covered panel for a school demonstration and I'm pretty sure I was well above 200 degrees, no issues there either. The glass panel looks really nice too.  It's the second picture down on the "Testing-Demos" page.  http://www.aluminum-solar-absorbers.com/solar-equipment-testing-demos.html if your interested.

   I'll take a bit of risk of some gassing under extreme stagnation circumstances than having fiberglass absorb water and become totally useless for insulation once wet.  Just my thoughts.

Great news on the panels !!! A bit of a word of advice though, this solar stuff is addictive !!  Agree on the return on investment for solar vs. wind turbines.  Wind is fun, and solar is practical.

Tom

[jarrod9155]

 Any one trie the taco 009 pump with built in controller that measures tank and collector temps looks like a good buy all in one everthing . Has deep switches for programing and led s for status and 3 speeds for efficency.   Would like a opion before I buy it .
                           And update on my panels I now have 7 of these copper collectors plus a 100 foot copper coil for heat exchanger . I did find 2 panels that froze and split the rizers . The whole drain back thing does worry me I wouldnt wont this to happen to me after all this work .

[Tom Sullivan]

Can't give any report on the new Taco pump, but will respond to the concerns with drain back.  Were the panels with the freeze damage in a drain back system?  If so, clearly they were installed poorly.  In my experience, I would be more concerned with freezing in an antifreeze system than drain back.  Having used antifreeze in my hydronic system at my truck dealership, I found it was really easy to get the ratio a little weak and the environmental antifreeze WILL freeze (actually, all antifreezes will) when seeing temps below the current protective level.  Another draw back with antifreeze; it's less efficient than water.

Install the drainback properly (it's not difficult to do) and it should not be a problem.  My system was exposed to over 20 below zero last winter, and regular night time temps below zero very frequently, and the system never had a problem.

Tom Sullivan

[GaryGary]

Hi,
I think you mentioned that the risers are 1/4 inch?

This is on the small side for drain back systems. 
The  Home Power Chuck Marein article recommends half inch risers for drain back systems.

His article is a good, hand-on source for designing drain back (or other) solar water heating systems.
Its listed in the top section on this page:
http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm
If you don't have access to Home Power, you can do the digital subscription -- I think its only $10 and it gives you access to all the old articles.

Gary

[jarrod9155]

They measure 3/8 not much more but a little bigger they were setup as a drainback and two also froze but at what point I dont know they most have worked for a while and also if I use 1 inch instead of 3/4 pipe will this help my drain back buy reduceing the pressure with 3/4 class m copper my pressure is 7.7 with a flow rate of 6.7 and 190 feet roughly of pipe .

[GaryGary]

They measure 3/8 not much more but a little bigger they were setup as a drainback and two also froze but at what point I dont know they most have worked for a while and also if I use 1 inch instead of 3/4 pipe will this help my drain back buy reduceing the pressure with 3/4 class m copper my pressure is 7.7 with a flow rate of 6.7 and 190 feet roughly of pipe .

Hi,
The bigger pipes are good.
The other important thing is to make sure that every plumbing run is sloped down toward the tank.  This goes for both the supply and return lines.  You also will need to slope the whole bank of collectors -- that is, the whole manifold line through all the multiple collectors need to slope so that the supply line comes in the low end of the bottom manifold and the return leaves from the high end of the upper manifold. 
With the relatively small risers, I'd say that you want to be particularly careful about the plumbing from tank to collector.

Gary

[crashk6]

Just to add my two cents on the choice of panel insulation, the Polyisocyanurate is the best choice you could make for the panels as the thermal breakdown point is upward of 200C or about 390F. Depending on the manufacturer the exact temperature will vary slightly with formulation/process differences but not by a huge range.

If your panels become that hot then you will have other issues than just the insulation.

   ~S~

[jarrod9155]

My next problem I have ran in to is how to set up the panel s ether all parrall or to banks a left and right and fill in the bottom and dump out the top middle .I have 7 panels so I would have to shed one to be equal if I divide them in to two banks right any suggestions on the best way to equaly provide water to all the panels .

[jarrod9155]

A little update got the panels mouted on the roof . Built a custom rack at 50 degrees tilt out of PT wood and raised it a inch of the roof on alumiun l brackets and sealed the brackets to the roof whith gesel 2300 silcone made for roofing . I put up 6 panels for now I have 2 more but will wait see how 6 do the others still need a lot of work .

[jarrod9155]

Finally got some good weather the panels are performing well in November in Maine my tank 370 gallons  hit 150 degrees today .

[MattM]

Its looking good!  Thanks for the update.

Geocel 2300 works well for sealing holes on shingles, you shouldn't have any problems if you used it in the right places.  Should last for several years.

[jarrod9155]

To save the trouble of going throw the roof I went over the side with 4 PVC to hide the 3/4 copper pipe works great you can still squeeze the elbows on after soldering and provide great insulation . On the brackets screwed to the roof I hope it last a little longer than  several years ,time will tell .

[jarrod9155]

Well it's been a couple months into winter and the outside temps are staying around  average 20 deg f . The system has had no problems since I added the taco 009 in 10/1/10.The  drain back has worked flawless with no freezing in the cold temps . My average tank temp 370 gallons is staying around 110 deg f has hit as high as 130 on sunny days back to back but that is rare this time of year in Maine . Over all I can't complain since install I haven't even had to turn a screw driver . The restored panels with the 1 inch foam board with alumina face has prov-en very effective at putting the heat on the copper tubes .  I still have one more panel to add to the system but will have to wait for the weather to get a little warmer . The flow rate is on the low side for 144 sq feet maybe 3 gallons a minute my head pressure is killing the flow rate 27 feet  and the next step would be a taco 013 and that thing uses some watts !!!  . I have noticed once the outside temps get into the upper 30 deg f the panels really start heating up and working better . My tank is a little big for 144 sq feet so I hope the extra panel should help with that . I have been using the hot water to pre heat my electric hot water . I called a couple solar stores that are local and tried asking there opinion on drain back systems and they replied back that won't work will freeze up in this state don't waste your time !!! I hope they stay wrong with that opinion .

[Tom Sullivan]

I called a couple solar stores that are local and tried asking there opinion on drain back systems and they replied back that won't work will freeze up in this state don't waste your time !!! I hope they stay wrong with that opinion .

My system has worked flawlessly, as far as drain back and trouble free from freezing, for two winters. Gary's has worked a lot longer than that.  Both of us see temps lower than -20 F.  I think those solar stores are either not familiar with drain back, or have installed or worked on improperly designed systems.  Done correctly, there should be no issues.

[jarrod9155]

And I'm thankfull I followed the advise of Gary and others here and not the local pros !!

[hayfarmer]

 nice job have a neighbor wants to do same to a chicken house

hayfarmer[/color]

[jarrod9155]

Seem to have developed a small problem , now I'm having a water bang sound now and then that is pretty loud like someone with a hamer on my roof or like a old house with old baseboard heat that has air in the system all I can think is that it is drawing air some were in the piping there was no visible leaks I could see in any of the panels or plumbing and efficiency is still there .

Has any had a pump go bad and cause this ?
Or is it most likely a air leak ?

[snowcrow]

Seem to have developed a small problem , now I'm having a water bang sound now and then that is pretty loud like someone with a hamer on my roof or like a old house with old baseboard heat that has air in the system all I can think is that it is drawing air some were in the piping there was no visible leaks I could see in any of the panels or plumbing and efficiency is still there .

Has any had a pump go bad and cause this ?
Or is it most likely a air leak ?

It sounds to me like the water maybe flashing over to steam    If you lower the Delta T and/or increase the pump speed, it may fix the issue if it is a flashover to steam.  It's the one thing I don't like about drainback systems 

[jarrod9155]

It could be that the sun is getting hotter and the system is new to that . Maybe add a bigger pump

[snowcrow]

  Here are a couple of links that may interest you!!  This gentleman live in Maine also, and has a 4 panel (4'x 8') system that provides most of the heating for his 28'x 24' shop.  It may make you think twice about not using a closed loop glycol  

http://www.arttec.net/Solar/BarnHeat.html

http://www.arttec.net/Solar/Stats/index.html

This is the kind of system I've decided to install at my remote camp in Vermont !