pics of my solar HW setup

[mikeyny]

This is the homebrew solar hot water setup i built a few yrs ago. Mostly from junk and left over stuff. The first picture is the picture window I removed from the neighbors house.

#2 is the wood box made out of 2 by 10 with styrofoam on the bottom and sides. The box is built to fit the glass. I also put in some scrap aluminum flashing and painted it (blue) for some reason. Must of been a can o spray paint kickin around somewhere

#3 is some left over epdm roofing rubber I glued into the bottom. I put several layers in for a heat sink. In the back ground you can see the experimental coil I tried at first. It worked but not good enough for me.

#4 I used an old 20 gal electric water heater to test the collector. It got hot in no time at all. It actually made a lot of steam. Good thing for the relief valve. That could have been dangerous

#5 is the finished set up. I never got a good picture of the new heat exchanger. I actually bought parts for it. I purchased 2 boiler header pipes of copper and simply put connecting half inch pipe from one to the other. Then I covered each pipe with more epdm rubber.
I have a few more pics somewhere. I can post later if I can find them. I use some half inch black onx pipe to get the water into a 40 gal water tank in the basement via a 3 speed grunfos pump. I was using an aquastat to control the pump vs temp but it was a bit unreliable. Now I just use a timer to turn it on and off during the day. The cold water enters the preheat tank first and then feeds into the gas fired hot water tank before getting to the faucets. With more time and effort I could probably make this whole system a bit more efficient. My gas bill went from 80 to 100 therms down to 15 to 25. We have 9 people using hot water every day. No doubt it looks a little funky leaning on the porch roof, but, I don't live in a fancy neighborhood. My neighbor asked my why his old picture window was on my porch roof. Modern art is what I said. Money in my pocket.

Mike

 

[Cazimere]

Betcha the neighbors were pissed when you took their window.

 

[mikeyny]

not only did I take their window but they paid me for it.

 

[Cazimere]

Thats quite a drop in the ole gas bill. Good job.

 

[mikeyny]

here is a good link to some solar stuff. Some of it is silly and some is good.

http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm

 

[sleepie]

how hot did the water get--and how many gallons could you make a day---i think this is fantastic---great job

 

[mikeyny]

unfortunately I never put an accurate temp gauge on the system. IN the summer the hot pipe almost gets too hot to touch and my hands are well calloused from construction work. One day, before I had the timer on the pump I forgot to switch the pump on manually, when I cam home at noon for lunch I turned it on and the inside pane of glass on that double pane window shattered right where the cold water enters the box. Now I am down to a single pane of glass. I have the system connected to a single 40 gallon water tank so on a normal day it heats up the tank completely with very hot water. I am sure If I had a larger tank or another one beside it I could get a bit more out of it. If I remember correctly the size of the collector can produce 35,000 btu on a good sunny day. I don't remember the actual numbers but you can only get so many btu per sq inch of surface area. I thought by adding more riser pipes inside or even double layering them I could get more out of it but it does not work that way. Someday I will add another panel and tank. The best thing about these systems is that there is literally no work involve once it is all set up. There is nothing like standing in the shower knowing that water didn't cost a dime. (even better if your favorite female is in there with you).

Mike

 

[mikeyny]

One other thing I forgot to mention. Many yrs ago when I had a propane fired hot water tank (the cost was killing us) I put a timer on the hot water leading to the shower. It is real simple if you have easy access to the pipe leading into the hot side of the shower. I still use it to this day. (the kids hate me for it). The real problem came about when my kids got into their teens ( 6 boys and 1 girl). When they were younger you could just get them in and out of the shower in no time at all, but teenagers are a different story altogether. You can yell all you want but there is no way I am going in there to wrestle a teenager out of the shower. God knows what takes them so long, soooo, I put the timer on and solved all of the yelling and long showers. I use a simple dishwasher water inlet solenoid. You have to use a bit of creativity to plumb it in but it works great. I use a 15 minute timer from hometeapot and put a peg in the cover at about 10 minutes. You turn the timer on before you get in and when the time is up, you hear a screech, sometimes a little profanity and bingo, out comes the teenager. When that timer snaps the solenoid closed the hot water instantly stops but the cold water continues to flow. I cherish the moment. By the way the timer is in the kitchen, well away from the bathroom. That alone saves me a lot of money and aggravation.
Mike

 

[sleepie]

mike can u tell me how---you circulate the water to your hot water tank?---do you use a heat exchanger?----exactly how does it get from the hot 40 gal tank to your shower----thanks i'm going to do this and i have alot of questions---sorry ,,,,pat

 

[mayhem]

I'm interested in doing something like this myself. I scored 4 panes of glass from one of our new branches last summer...they're somehting like 4x7 or maybe 5x8 and are low-e double paned glass, but since they weren't the anti-heat solar glass we paid for they had to take every single pane off the new building and replace it with the right stuff...what I couldn't take they smashed onsite in the dumpster...made me cry to see $40k in glass panel go to waste like that.

Solar hot water is my next logical step to going oil-free (wood stove weas the first step, I've probably reduced my winter consumption by 1/2, but since the price per gallon has easily doubled I barely notice it). If a home brewed system will actually work efficinetly enough to do the trick, I see no compelling reason to pay $5k+. I've been thinking that it would make sense to take an extra collector or so and feed sometihng like the size of an oil tank instead of a hot water heater (have to insulate it of course) and use the excess hot water to run my heated basement slab, further reducing my oil consumption.

Got any plans or more detailed info? I think I'd like to try this.

 

[mikeyny]

I have the tank in the basement next to the gas fired hot water tank. The pre-heat tank has a 3 speed grundfos pump on it to circulate the water in a loop up through the solar panel and back to the tank. I have the gas fired water tank plumbed so that the cold water entering it is diverted (via ball valve) to the preheat tank. As the cold water goes into the pre-heat tank the hot water from the pre-heat tank flows into the cold side of the gas fired tank. Now the water entering the gas fired tank is either warm or very hot depending on what time of day it is. This saves a significant amount of energy. There are many ways to improve my system. presently I use a simple timer to turn the pump on in the am and off in the pm. Most store bought systems have a series of temp sensors that control the pump to get maximum efficiency. In other words if the water in the panel is cooler than the water in the tank the pump won't run. I experimented with a few snap disk stats but it was not reliable enough. I could simply buy the solar tank controls online (I forget the actual name of it) but I am too cheap. Someday I may come across another homebrew way to do it. Many people talk about tracking the sun to get max efficiency. For the amount of work and money it takes to do it I don't think it is worth it unless you have the time to tinker and build your own tracker. I had experimented with series of cad cells from oil burners to see the sun and trigger relays to move the panel but never finished the project. Good luck with the project. It is definitely more rewarding to build it on your own with some salvaged stuff. I have gotten pretty good at junk picking and collecting good stuff from junk piles.
Mike

 

[webbie]

BTW, a "junk" tip which I found valuable when building a sun room at my old house.

The double insulated glass in patio doors is a relatively standard size, and often you can find damaged doors in lumber yards or home centers - and take the glass out of them. Way back then, I paid $10 a sheet for it - probably more now, but still a lot cheaper than buying at full price. I used 6 sheets of this for making my solar sun room.

 

[ozarkjeep]

thanks for the pics Mike!

One question, what keeps the water in the collector from freezing?

 

[mikeyny]

Ooops, I forgot to mention I use the wood boiler to make the hot water in the winter. I drain the system down. However, some of the commercial systems have a drain back option which drains the water back down into the tank in the night time. I am not sure how they do it though . On one posting here I was looking for advice about using antifreeze (non toxic) in the system and running it through my heat exchanger set up that I use for the wood boiler for domestic hot water. That way i could run it all winter, but I am still not sure If I would get enough hot water in the winter months. Also, when you are looking for glass, I think the older glass is better. I am pretty sure the newer glass with the low e rating may keep some of the suns energy out of the panel.



Mike

 

[eba1225]

Mike,

What is the material used for the piping in the panel? copper?

This is something I am looking to build to help provide additional hot water.

Erik

 

[mikeyny]

Yes it is copper. I am sure it is quite pricey now. I purchased 2 boiler header pipe at my local plumbing supply house. F.W. Web has web site I think. The header pipes are 1 or 1 and a quarter inch pipe with half inch nipples coming out about every 4 inches. I forget how many I used. But what you do is make a bunch of the same size half inch copper pipes and insert them into the nipples and connect one header to the other.

 

[mayhem]

I may have missed it along the way, but do you heat the water directly in the tubing through the panels or do you use another fluid in there and a heat excahnge coil in the tank? I'm guessing direct water heat if you drain it in the winter.

 

[ozarkjeep]

Interesting, I would have have to heat coolant in the collector, and have a water/water exchanger in side to heat the water.

since im sure I would forget to drain it off at night, and when its cold!

 

[mikeyny]

I do heat the water directly through the panel. I am pretty sure the systems that drain back do it automatically with some sort of control or timer.

 

[raybonz]

One other thing I forgot to mention. Many yrs ago when I had a propane fired hot water tank (the cost was killing us) I put a timer on the hot water leading to the shower. It is real simple if you have easy access to the pipe leading into the hot side of the shower. I still use it to this day. (the kids hate me for it). The real problem came about when my kids got into their teens ( 6 boys and 1 girl). When they were younger you could just get them in and out of the shower in no time at all, but teenagers are a different story altogether. You can yell all you want but there is no way I am going in there to wrestle a teenager out of the shower. God knows what takes them so long, soooo, I put the timer on and solved all of the yelling and long showers. I use a simple dishwasher water inlet solenoid. You have to use a bit of creativity to plumb it in but it works great. I use a 15 minute timer from hometeapot and put a peg in the cover at about 10 minutes. You turn the timer on before you get in and when the time is up, you hear a screech, sometimes a little profanity and bingo, out comes the teenager. When that timer snaps the solenoid closed the hot water instantly stops but the cold water continues to flow. I cherish the moment. By the way the timer is in the kitchen, well away from the bathroom. That alone saves me a lot of money and aggravation.
Mike

Hello Mike,
Just a line to let you know I enjoyed this post lol! I could easily do this but the wife may not like the idea! My teens are the real culprits though. You have lots of good ideas on solar etc. and you'd be welcome here as my neighbor anytime.. Keep up the great thinking!

Ray

 

[webbie]

Questions - or comment, anyway.....

Having rubber as the backing or wrapping the pipes.....I don't think that stuff is a good conductor. Why not just paint the pipes black (you can even get solar paint), and use sheet metal for the rear? I think that would perform better.

 

[nanama72]

For a good backing, do you think bricks painted black would absorb more heat than stainless steel painted black?

 

[raybonz]

For a good backing, do you think bricks painted black would absorb more heat than stainless steel painted black?

I think due their mass that bricks painted flat black would hold more heat and release is slower for a longer period of time..

Ray

 

[webbie]

You have to consider exactly what you want the material to do. Black will soak up heat well - but then you want to transfer it somewhere - to water or to mass. So the sun is the input, and the water or the bricks are the storage.

If you are heating water, than steel, copper or stainless painted black (there are even special solar blacks) are fine, but the tubes (copper, etc.) have to be in good contact with the sheet in order to transfer the heat from the backing to the water. Insulation is usually used behind the panel, I have seen foams boards of certain types used for this, but semi-rigid fiberglass might also do.

 

[mikeyny]

My solar collector is made mostly of the stuff I had on hand. The rubber seems to be working well. My gas consumption went from around 80 to 100 therms to around 20 to 30. I am not sure if some other heat sink material could be better that mine or not, I have nothing to compare it too. Also it is hard to compare unless usage, degree days, good sunny days and other variables are equal. This works so well for me I may build more in the future when the time allows.
Mike