A DIY Solar Water Heater From Plastic Bottles

Solar water heaters are probably the most widely used solar product worldwide, especially in Asia and other parts of the developing world it is a constant with any new construction. Out of Brazil comes this plastic water bottle based water heater created by Jose Alano a retired mechanic. He created a simple, cheap, energy saving rooftop solar water heater which is benefiting thousands of people across Brazil. Alano refused to throw away plastic bottles and packaging to end up in the landfills. In his words “Being 59 years old, I have had the opportunity to witness the technological advances of science, which improved food storage. But nowadays, some packaging weighs almost the same than the food itself! Years ago, my wife and I realized that we were not prepared for this new form of consumption.

Using his basic knowledge of Solar water heaters he and his wife created the green alternative version making use of 100 plastic (PET) bottles and 100 Milk Cartons there by getting rid of their waste responsibly.

Alano’s water heater won the Superecologia prize, offered by the Superinteressante magazine for renewable projects in the not-for-profit sector. He has made his design patented and available to use as a not for profit design. The only restrictions are on industrial production and politicians claiming credit for it!

The Invention

The standard solar water heaters cost a couple of 1000$ and have copper as a main element. The Plastic Bottle solar water heater is based on the thermosyphon technology which is used in many solar water heaters. It makes use of the circulation of water based on density; hot water which is less dense moves upwards while the cold water which is denser moves down. Alano estimates that to heat water for a shower of one person, a 1m² panel would be enough.

Materials needed for construction:

The only material required to build a recycled water heater are:

  • 2L plastic bottles (60),
  • Cartons (50)
  • 100mm PVC pipe (70 cm)
  • 20mm PVC pipe (11.7m)
  • 90-degree 20 mm PVC elbows (4)
  • 20mm PVC T-connectors (20)
  • 20 mm PVC end caps (2)
  • PVC glue
  • Black matt paint
  • Paint Roller
  • Sand paper
  • Self-amalgamating tape
  • Tools – Rubber hammer, saw, wood or other material for the support.

Once you get everything ready check out the diagrams in this DIY Leaflet online (PDF format in Portuguese, but the diagrams are easy to follow). use the 100mm PVC pipe as a mold and cut off the bottom of the bottles. Cut the 20mm PVC pipes into 10 x 1m and 20 x 8.5 cm pieces, and assemble with the T-connectors. Cut and paint the cartons (page10-12), as well as the one-meter long pipes. Assemble according to figure B.

The panels must be placed at least 30 cm below the tank and be sited on a south facing wall or roof. To optimize heat absorption, the panels must be mounted at the angle of your latitude, plus 10°. In London, for instance, the panel’s inclination should be 61°. Alano recommends that the plastic bottles in the panels should be swapped for new ones every 5 years: ‘Over time, the plastic becomes opaque, which reduces the heat caption, while the black cartons can be repainted.’ So once the bottles become opaque it is time to replace the bottles and send the used ones to the recycle dump.

Check out a video of a Alano’s bottle solar heaters below:

Such a useful way to utilize plastic bottles: green, clean and energy efficient! Reduce Reuse Recycle the 3 R’s at work! Live Green!

Source for data and Pictures – The Ecologist

25 thoughts on “A DIY Solar Water Heater From Plastic Bottles

  1. Mahesh Brahmbhatt

    We have interst in the Solar Energy with Plastic Botle wich make 50W.
    Please send us more Info.

    Mahesh Brahmbhatt

  2. Harley

    how do you get the water to travel threw the bottles?, i’m making one of this in a mini make for my school project but i can’t figure out how to get the water to travel, help me? any suggestons just email me, hsharliejade@yahoo.com, they come to my phone so ill get them anytime! thanks for the help!<3

  3. s ward

    The link to the DIY instructions is broken.
    Do you have copy of the document you can post or forward please?

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  5. Surja Deka

    sir,i m planning to do it as my B.tech project under production engg….can you send me info about this…it will be a great help…plz email …surjadeka@gmail.com

  6. Satish

    Dear sir,

    I am interested in using this green technology. Where shall I get the manual for the same in inglish?

    Waiting for favourable reply!

    Thanking You


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  8. Asa

    Is there a new link to the DIY leaflet? The one on this page does not work. It cannot find the site.

  9. Asa BHere

    Hi, can you help me find a working link to the DIY leaflet for the solar hot water heater using plastic bottles?

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  12. Alex

    Just a question: how do you control the risk of legionellosis on the water? With the temperature and the external conditions of the installation, it might be dangerous if is not well controlled.

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  20. Gerald Young

    not sure but it looks to me like all they did is replace the glass cover with plastic bottles, this may work well but it seems that keeping the bottles clean would be a lot harder than a flat glass or plastic panel, replacing the plastic bottles as they become damaged would be a bit of a chore you would have to shut down the system then disassemble it to replace even one bottle, if you have access to all the tubing and materials needed to make a solar water heater wouldn’t you make it as simple to repair and do maintenance on as possible? if that is all you have to work with I can see using them but I just don’t see plastic bottles holding up for that long

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  25. Colin Mitchell

    The pipe can be much smaller diameter.
    Simply use a single length and make a circle without kinking the pipe and add the plastic bottles.
    Each time you come back to the start, place the next circle above the previous.
    This way you will finish up with loops above each other.
    As the water gets hotter and hotter, it get lighter and lighter and it will flow out of the top.
    The top can be 5cm higher than the bottom for each loop and each bottle will absorb a maximum of 20 watts. The bare pipe alone will only absorb 5 to 10 watts per bottle-length so the addition of the bottle increases the efficiency 4 times or MORE. The reason is the air in the bottle surrounds the whole of the pipe and transfers heat and the air in the bottle will be considerably hotter than the outside air.
    This whole arrangement is much cheaper than adding elbows and Tee pieces.

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