# Homemade water heater



## greg273 (Aug 5, 2003)

I'm wanting to chat with anyone who has been using a homemade solar water heater. I have plans to build one, using an old water-heater tank stripped of insulation, painted black, and set on the south side of the house. I would also have a collector built from copper pipe helping to heat the thing. This seems pretty simple, but I'd like to hear from some people who have actually done this.
My plan is to drain the system in the winter, when I will switch over to a wood-fired heater. I'm debating whether to even include a gas-fired backup heater. Seems like a lot of complications, but who said harvesting energy was easy?
Still, I'd love to make this work.
Any advice is surely appreciated.


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## SolarGary (Sep 8, 2005)

Hi,

I have not actually built one of these, but have heard from a lot of people who have, and the reports are generally good.

I'd take a look here:
http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm#Batch

The book (free download) thats listed first has designs for many batch water heaters, and has whole section on actual performance people have gotten out of ones they built.
The report from OSU (next item down) has carefully recorded performance for a batch heater in Bend, OR (a pretty tough climate), and a good set of plans.

Several other interesting heats listed below this with plans.

I'm not sure you really need the copper pipe arrangement -- take a look at the plans above, and see if maybe you can do without that?

Good Luck!

Gary


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## greg273 (Aug 5, 2003)

Very good links Gary! Thanks!


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## Fire-Man (Apr 30, 2005)

greg273 said:


> I'm wanting to chat with anyone who has been using a homemade solar water heater. I have plans to build one, using an old water-heater tank stripped of insulation, painted black, and set on the south side of the house. I would also have a collector built from copper pipe helping to heat the thing. This seems pretty simple, but I'd like to hear from some people who have actually done this.
> My plan is to drain the system in the winter, when I will switch over to a wood-fired heater. I'm debating whether to even include a gas-fired backup heater. Seems like a lot of complications, but who said harvesting energy was easy?
> Still, I'd love to make this work.
> Any advice is surely appreciated.



Greg, I made one system by using heavy gauge 5 V tin(using what I had) and a discarded sliding glass door. What I did was build a 2"x4" box the size of the glass door--plywood on the back with 5/8ths insulation board attached to the plywood on the inside of the box--then cut the 5V tin to fit inside the box with the V's turned towards the back--attach and stablize the tin--then I bought 50ft of 1/2" soft copper and made a jig to bend it to where it was---starting at the bottom of the 2x4 box---bent to where it went almost from one side of the box to the other(about 4" in) about 6" apart from bottom to the top of the box with it extending outside the box at the bottom and the top. I attached the copper to the tin using copper clamps so it was touching the tin as much as possible. I found a thermal switch(TS)that closed at 135 degree's and attached it to the tin on the back side (close to the middle of collector)before I secured the tin and ran two wires attached to the TS through the insluation board and plywood. I sprayed the inside with flat black--then attached the sliding glass door using weather strip to seal the cracks. I had a well insulated metal tank to hold the hot water(non-pressurized). The way it worked---A small pump (1gpm)would be turned on when the collecter got to 135 degree(I will give details if needed) the pump would pull water out the holding tank from the bottom(hot water rises)---it pushed the water into the bottom of the collector, up through the copper pipe out the top---back to the holding tank--circulating till another thermal switch that was attached to the pipe at the bottom of the holding tank reached 120 degree's--it would then shut off the pump. When the water temp dropped a few degree's the pump would start circulating again, but only if the collector was 135 degree's or hotter. I used a demand pump to pump the hot water from the holding tank into the house. I live by byself so I would check the water level of the holding tank and add extra water as needed. 
I didn't go into details about aiming the collector or insulating the pipes--You know you have to do that. This system worked great--the weak link--the pumps---I built this with things I had laying around--except for the copper--If I had of bought a pump that could move hot water--I would be using it now----I was Just "Playing"---I will set it back up soon. Good Luck. Randy


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## Micahn (Nov 19, 2005)

greg273 said:


> I'm wanting to chat with anyone who has been using a homemade solar water heater. I have plans to build one, using an old water-heater tank stripped of insulation,
> Any advice is surely appreciated.


I would think that it would cool off to much at night without any insulation on it.
Would it be possible to have another tank that is insulated some place and have a circulating pump move the water during the day ?
Back when I was installing systems we even put in heat traps (they are very easy to make) to keep the water from circulating by itself during the night so it would not loose heat. Depending on where you live and just when you use the most hot water would help in deciding what would work best for you.
If you use the most hot water in the mornings to take showers and suck then you might have a problem. If you take your showers at night then things might not be so bad. You might just have to change how you do things a little to make the system work best.


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## greg273 (Aug 5, 2003)

Sounds like a good set-up, Randy. I'm thinking to rely on a thermosiphon to circulate the water, setting the tank higher than the collectors. My main concern is how to pressure-regulate the system. It would be in-line with the house water, relying on the SHurflow2088 pump to send water up to it. When the sun starts heating the water, I'm curious as to what kind of pressure that would exert on the system, and if I need some sort of expansion tank/relief valve to keep things happy...
Randy, did you paint the copper coils also?

Nighttime heat loss would defnitely be an issue with an un-insulated tank. Perhaps a check-valve leading from the collectors to the tank would stop a 'run-away' heat loss situation.


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## Fire-Man (Apr 30, 2005)

greg273 said:


> Randy, did you paint the copper coils also?


Yes I Did. I have never "played" with the type system you described. Good Luck. Randy


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## Ross (May 9, 2002)

I should think a solarr tank as described could work very well. Too well even! So please be sure a functioning T+P releif valve stays fitted.


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## jnap31 (Sep 16, 2005)

I am building one by next summer.


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## greg273 (Aug 5, 2003)

I think I'm going to abandon the copper coil idea and just use 3/4 copper pipe and fittings to make a collector, about 24"x36". UNLESS I can figure out a way to shape this copper tubing! I was messing with it today, and it seems like its gonna be a pain to get this stuff shaped the way I want it. Seems like I'l be able to get a tighter turning radius with 90 degree street elbows.
Randy, you said you made a jig to bend your copper... can you describe what you did?


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## Fire-Man (Apr 30, 2005)

Greg
I bought the soft copper that you can get in 50ft rolls and other lengths too. I bought the one that was app 1/2" OD and cut a 1/2" piece of plywood the width I wanted the copper seperated ---I think I cut it 6" wide and rounded one end-then cut two more pieces 7" wide and rounded one end --then screwed them together where the larger pieces hung over the smaller piece 1/2" on two sided and 1/2" on the round end. There is a copper pipe bender you can get that would work but I just made mine. I feel if you were to use 3/4" you might move the water to fast and cause your collector to cool to quick. My next one I make---I am going to use 1/4" or no larger than 3/8". I already bought a 1/16" piece of 4x8' sheet of steel for my next collector. Having a good collector plate will help alot because you want the Sun to heat the Big piece of steel through the glass(kinda like a Solar Cooker) and have your copper tubing attached to the sheet of steel. You will get ALOT more hot water this way. I also feel you might want to build it larger than 2'x3'---that is not very big, but I feel sure you will get some hot water out of it. I am thinking I will build my next one at least a 4'x7', maybe a 4'x14' because I found a few pieces of FREE glass 4'x7'--I Like Free.

One test I did with the one I made---------on a 80degree sunny day I got the water to 138 degree's as it dumped out the top of the collector on one pass through the collector, but it was a real low GPH water movement. Good Luck!! Randy




greg273 said:


> I think I'm going to abandon the copper coil idea and just use 3/4 copper pipe and fittings to make a collector, about 24"x36". UNLESS I can figure out a way to shape this copper tubing! I was messing with it today, and it seems like its gonna be a pain to get this stuff shaped the way I want it. Seems like I'l be able to get a tighter turning radius with 90 degree street elbows.
> Randy, you said you made a jig to bend your copper... can you describe what you did?


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## greg273 (Aug 5, 2003)

Yeah, the solar collector will be bigger than 2'x3', i got ahead of myself and was working on the wood-fired collector, which I figure doesn't need to be quite as large, due to the increased heatflow.
Now I'm getting worried about what the plumbing inspector is going to say about all this. I'm thinking a conventional water heater will be needed, if only to satisfy the county.


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## MELOC (Sep 26, 2005)

don't worry greg. it makes a good insulated tank and the breaker can be turned off, lol.


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## michiganfarmer (Oct 15, 2005)

I built one for my dad. We took a water heater tank, painted it black, and built a glass box around it. It only gets the water up to around 75 degrees in the middle of the summer, but it sure reduced the load on his electric water heater.


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