DIY Solar Powered Water Heater: 3 Steps




Introduction: DIY Solar Powered Water Heater: 3 Steps

In this first Ecowanderer DIY instructable you will learn, step-by-step, how to make a simple solar water heater from simple household items.

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Now, on with the instructable.

Here is a brief description of the process: Water, inside a water reservoir, will flow through a pvc pipe which is being heated through a simple parabola which reflects sunlight.


  Here’s the list of the materials you’ll need:

-          - Round-shaped plastic bucket

-          - Aluminum foil

-          - Water barrel (or another round-shaped bucket)

-          - 1 metre long pvc pipe, with 5cm of diameter.

-          - 2 pvc adaptors: one to join two pvc pipes, and one with a 90 degree angle (both to fit a 50cm diameter pvc pipe)

-          - Black spray paint

-          - Strong glue/plastic weld

-          - Saw

-          - Kitchen knife and a lighter

-          - Duct tape

-          - Black&decker with a small drill piece and an abrasive piece for polishing

-          - Protective mask and eyewear

Step 1: Building the Parabola

Let’s start with the round-shaped bucket. Start by cutting the bottom with the saw or a heated kitchen knife so as to end up with a plastic cylinder (the cover of the bucket is not needed). Now the purpose will be to cut this cylinder in half. Start by marking or finding a straight line that is parallel to the height of the bucket (place the bottom-cut part facing your workbench and use your saw to cut through it.

Although not harmful to the project, try to cut in a straight line the best you can. Repeat the process in the exact opposite line of that which you just cut. You should not have 2 small parabolas! To take the best advantage of the power of the sun, glue them together with strong glue or a plastic weld.

Now, to achieve the mirroring effect, grab some aluminum foil. In order to glue/fix it to the plastic without wrapping the foil or creating any crumbs, cut small pieces (in length) but that are large enough in width to cover the width of the parabola. Use simple glue or duct tape to fix it in place.

Step 2: Getting the PVC Pipe

Now that the parabola is completed, let’s focus our attention to the pvc pipe. You can find one in your local hardware store or in a gardening shop. It is important that the length of the pvc pipe is greater than the length of the finished parabola.

In our particular case, we used a 1 metre long pvc pipe which had 5 cm of diameter (50 dm). Afterwards, get a black spray can. It is crucial that the type of paint chosen does not reflect light.  In the project, we used jet black paint, so look it up.

Before painting, we passed the scrubbing sponge through all the pipe in order to make the paint more adherent to the pvc plastic.

Put on your protective mask and eyewear and start painting the pvc pipe. Remember to do this in a fully ventilated area!

Step 3: Building the Water Reservoir

Now all you need left is a water barrel as a water reservoir. You should be able to find one at a local hardware or gardening store. If you can’t find one, a plastic bucket will do, although make sure the plastic is not composed of any dangerous chemicals that can be transported to you when the water is going by.

To finish, you need to mount together all parts. The most efficient solution to connect the pvc pipe to the water barrel is to buy a 90º pvc adaptor and an union pvc adaptor (remember to check if the adaptor’s diameter and your pvc pipe diameter are the same!)

Place your water barrel bottom up and, with a pen, mark the diameter of the adaptor in the bottom of the barrel.  Get a drill with a small diameter and, inside the drawn circular line, drill holes next to each other. Use a knife to cut the hole and attach a polisher to your drill to manually increase the size of the hole until the 90º adapter can fit in.

Then insert the union adapter through the inside of the water barrel and connect it to the 90º adapter. Make sure you make enough pressure, because the point of the union adapter is to serve as a physical barrier so water does not leak away.

After that, just mount everything together and you're done! Easy, right?



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    20 Discussions

    i get the idea of what the system is intended for, and that is to have something like a single serve of hot water, and that any additional hot water is entire by chance. the only thing i would suggest , is plexi-glass for the parabola. take silver spray paint, cover one side then when mounting the parabola do so with the unpainted side facing up. the idea is greater reflective power. try that and let me know how it works

    You could have made you life easier with the right tools but yes i know its not the point of the execise nice job

    easy enough to modify to be more effective
    but does the heated water in the pipe heat the rest of the barrel's water?

    Hi. The idea works, maybe needs some modifications and/or improvments already observed from commercial water heaters. Here in Brazil there is at least a couple of low cost DIY water heaters. One is made almost completely out of recyclable waste (PET bottles and "tetrapack" (milk, juice etc.) boxes. Another one, more ellaborate uses PVC pipes and PVC "honeycomb" plates - like those used to finish internal roof office ceillings in some places. Here are links to it, I´m not sure if there are english versions but there are a lot of pictures. - recyclabe materials version - another version.
    These heaters are good to be used in certain conditions. Like regions where should not be snow build up on it, altough the second one can sustain some amount of low temp weather; they will not heat more than 50 to 60 deg Celsius, so PVC and thermoplastic containers can handle the hot water. They all use PVC and tests habe been made with certified institutes that states that after some weeks the water will not show chemicals traces, this means after some time running the system the water will become potable. Also, the PVC exposed to the sun is to be coated with good quality black Ink to protect PVC pipes from UV radiation. All this is a cost X benefit and of course, having fun building it and getting results. As an example, here one can build a "ASBC" system (second link) spending like 10 to 20% of the cost of a professional system. This is getting such importance that professional companies are beginning to offer similar "low cost" systems that are around 3 to 4 times the cost of the DIY version but will use similar concepts and materials. The ASBC version is mature and is being developed, tested and in use since several years ago.

    4 replies

    Nice info.
    You wouldn't want to translate that 2nd PDF file into English would you.
    About 300 million of us might appreciate it.

     Oh, right. Well you would be better off PM mad_b directly. I should warn you that that pdf has nothing to do with mine. Sorry for the misunderstanding!

    Tin foil probably wouldn't be the best choice for a reflector. Unless it is perfectly smooth, it acts as a refractor. You would probably have better success using a glossy white paint.

    You should use a peace of PVC, cut it in half and use that instead of a bucket.Also heating up the PVC may melt it and cause toxins to get in the water.Use a a mettle tube at the same length and width and it will work the same and heat up the water faster.

    I might be wrong here, but I believe this setup to be extremely inefficient..
    First of, the fact that you are only heating water in the small pipe and leaving the water in the tank to stay cool cant be the best way to do this..
    Then again it might work like air for all I know, circulating the warm water upwards and allowing the cold to fall intot he pipe to be heated in return... anyone got a clue if this is the way it works?
    Secondly I am sure you should use a metal pipe as I know for sure it's a better heat conductor then plastic and would allow for a much more efficient system.

    7 replies

    Thanks for the comment.

    The pipe/reservoir setup was set in such a way that will allow the warm water to go upwards. But that was not the main reason. The initial intention was to have the pipe so hot (hence the black paint) that when the water flows by the pipe it will instantly heat itself to comfortable shower levels.

    I indeed pondered about a metal pipe, but I wanted to keep the overall cost small and I couldn't use brass or aluminium or copper due to potential toxicity issues.

    I see why you'd use pvc instead of metal as it's so cheap but as someone else said most common metals dosent release toxic substances, at least not at those temperatures.
    But I'm still currious about the efficiency of the immediate heating system you have in mind, have you tried it yet?
    I just cant imagine it working for more then the first "load" of water in the pipe, unless hot/cold water behaves like hot/cold air does, and even then I wonder how long it would use to heat the entire tank with such a small area being heated by simply a reflectic parbola as I really dont think you can get it hot enough without a metal pipe and some lenses to focus more extreme heat onto the pipe...

    But to make it work I think he needs to have line going to the top of the drum. So one side of the pipe goes to the top and one side goes to the bottom.

    I haven't tried it yet (as you can see, i just need a tap to prevent the water from being to waste), but i'll post a video of it working when the weather is less rainy and more sunny around where I live.

    Aside from cast ion, copper is about as non-toxic as it comes. Stainless steel contains chromium, and PVC exposed to UV light gives all sorts of fun chemicals. Frankly though, you shouldn't really be worrying about any, as the exposure levels are so low.

    Yeah you're right.  Brass and aluminum aren't toxic, and they don't cause damage unless I would inhale the fumes or such.

    Copper would definitely be the best choice, but I didn't have the tools or the money for it, as do most people.

    Great pictures and what seems like a good idea but have you tried it out? Unless I'm missing something there's no way for the water to circulate through the pipe. You need a longer (and probably skinnier)pipe that comes from the bottom and dumps into the upper part of the container.. The hotter water should then rise and circulate. You may need a small pump, when I first tried using a 150' garden hose to solar heat the pool the water wouldnt rise high enough to dump back in. Now I have hose attachments on both the intake and discharge pipes so the water siphons. With the hose coiled through the yard, I get between 15-20 degree difference from morning to late afternoon which is enough to keep the pool open untul early december..of course Im in florida so......

     P.S. I wouldn't say MOST could afford the other materials, a better word may be "some"

    2 replies

    for the pool a tarp covering it when closed  will help greatly, as for the circulation you ars right a small pond pump works very well so long as your temps dont get too high.

    for the pool a tarp covering it when closed :

    Yea a tarp or solar cover would probably help but would also be aggravating for daily use. Especially with an above ground pool and my  physical limitations. Previous atempts included the hose laid out on the south facing roof of the house but a pump large enough to lift the water also flowed to much water so there wasn't much heating. A smaller pump with the hose on the ground worked but was a pain to use. The latest seems to work well but looks like (insert profanity of choice)  I'll probably do an "ible" when I reconstruct it