I was inspired to build efficient, cheap, and fully home-made diy solar panels by studying ingenious solar thermal system shown on the cansolair website.
What this incredibly simple solar system does, is that it basically heats the indoor air directly which makes it perfect for supplemental home heating. The most interesting part: home built solar collector is almost entirely constructed out of empty aluminum cans!
Between renewable (ecological), and conventional (non-renewable, non-ecological) energy sources, the first choice for exploitation is always conventional energy with profit as the only important factor. For example, high profit is obtained by monopoly on strategic crude-oil reserves…
When it is sunny, regardless of outdoor temperature, pop cans heat up very quickly. The fan drives warm air from inside of the cans back into the room. For those living in remote places, or those who want to achieve full off-grid autonomy, simply hook up small PV solar panels or wind generator and wire them to power the air blower.
I have to mention that, before going solar, it is advisable to perform a thorough assessment of your home insulation in order to improve heating efficiency and minimize all possible losses. This is very important because after minimizing heat loss in your home, you can actually install smaller solar system and get the same result as with the twice bigger heating system.
Do-It-Yourself Solar Panel Construction
Housing for diy solar panels is made of wood (plywood 15mm/0.6in), while its front is 3mm/0.12in thick Plexiglas/polycarbonate sheet. Tempered glass can be used as well. The back of the solar collector is insulated with 20mm/0.8in rock wool or styrodur. Solar absorber is made out of beer and soda cans, painted in matte-black (paint resistant to high temperature). The upper / top part of each can is cut and bent in a way that provides highly efficient heat exchange between the cans and the flowing air.
Step by Step Building Guide: DIY Solar Panels
First, let`s collect empty pop cans for solar panel assembly. Try to wash them thoroughly, otherwise they will begin to spread odors very quickly. Attention! Cans are generally produced out of aluminum, but there are some made of iron. You can test different cans easily with magnet.
Please pay attention and try to precisely cut and form small fins at the top of each can. Idea is to encourage turbulent airflow inside pop cans so that air passing through the tube can collect more heat from the warm pop-can wall. Carefully cut the top of the can in the form of a star, and then distort free parts using pliers (Picture 1). It is important to do all this before gluing the cans together. We have marked three holes on each can with a nail, then drilled the bottom using tools shown on images 2 and 3. More details can be found on diy solar panels video tutorial page.
Picture 1 Picture 2 Picture 3
WARNING! This procedure is extremely dangerous because pop can walls are very thin. Sharp parts may cause hand injury.
After drilling is completed, small parts of the metal could remain in the can. Use pliers to remove these parts.
Do not remove pieces of sheet metal and debris with bare hands!
Remove grease and dirt from the surface of cans. Any synthetic degrease agent will do the job. Do this outdoors or in a well-ventilated room.
WARNING! This procedure is flammable! It is dangerous to do this near open flame or cigarette!!!
Glue all cans together using adhesive silicone resistant to high temperatures, at least up to 200°C/400°F. There are products for bonding that can withstand temperature up to 300°C/570°F. Top and bottom of all pop cans are compatible and fit perfectly one onto another. Put some glue or silicone on the edge of one can and press it against another one. In this way the glue/silicone will not run away from the edge. Picture 4 shows inside view of two pop cans glued together, while series of stacked and finished cans is shown in Picture 5.
Picture 4 Picture 5 Picture 6
Picture 7 Picture 8 Picture 9
Prepare a template for stacking cans – “L” profile shown in Figure 6. You can use two ordinary flat wooden planks and nail them together. Template will provide necessary support for solar pipe during the drying process. In addition, secure the cans onto a template using ordinary jar rubber.
Pictures 7, 8 and 9 show the gluing process. Series of glued cans form a solar pipe. Picture 10 shows the pipe fixed in motionless position until the glue gets completely dry.
Picture 11 Picture 12 Picture 13
Air intake and exhaust boxes for diy solar panels are made using wood or aluminum, 1mm/0.04in thick (Figures 11 and 12). Gaps around the edges are filled with adhesive tape or heat-resistant silicone. 55mm/2.16in diameter cut-outs are drilled on one side of intake/exhaust box. Drilled parts can be seen in Figures 12 and 13. This is where the first row of cans will be glued to the air intake/exhaust boxes. Check out how it looks when all parts are assembled and prepared for painting (Figure 13).
The adhesive dries very slowly. Leave it to dry for at least 24 hours.
Solar absorber fits in the casing made of wood (Fig. 14). Back side of diy solar panels box is made out of plywood. Insulation of solar panel is achieved by applying rock wool or styrodur. Installed insulation can be seen in Figure 15. Pay special attention onto insulation around the openings for the solar collector air inlet/outlet.
Next step is preparation, protection and painting of timber box (solar panel housing). Special hooks have to be attached to all four corners of the solar collector, so that it can be easily mounted on the wall (Fig. 16) using 10mm/0.4in screws (Fig. 17). Empty box is placed on the wall in order to precisely mark the spot for drilling the air inlet/exhaust.
Picture 14 Picture 15 Picture 16 Picture 17
Picture 18 Picture 19 Picture 20
At the end, solar absorber is painted black and placed inside the housing. The casing of diy solar panels is covered with plexiglass attached to the frame and thoroughly corked with silicone. Polycarbonate / plexiglass is slightly convex in order to gain additional strength. You can see installed solar absorber without plexiglass in picture 18. Complete solar collector is shown on Picture 19, and finally, installed solar thermal panel can be seen in Picture 20.
Check out our pop-can diy solar panels on YouTube. Video shows how solar panel operates on a bright day. After first 20 minutes, panel raised the air temperature inside living room to 50°C/122°F.
Important note: This solar thermal system is not able to accumulate thermal energy after producing it. When it’s sunny, solar collector produces heat, but it is necessary to use it immediately for heating the room. If the sun does not shine, it is necessary to interrupt the air supply to the solar collector, otherwise the room will begin to slowly cool off. This can be solved by installing shut-off valve, which will reduce unnecessary heat loss.
Differential thermostat (snap disc) controls the fan. This thermostat can be bought in better-equipped electronic component stores. Thermostat has two sensors. One placed inside the top opening for warm air, the other inside the lower opening for the supply of cold air in the solar collector.
If on/off temperatures are set carefully, diy solar panels are able to produce an average 2 kW of energy for home heating. This generally depends on how much sun do we have during the day.
Final Chapter: Solar Panel Test Drive
Solar collector dress rehearsal was carried out in the backyard before installing the system on the house. It was a sunny winter day, without clouds. Our air blower fan is actually a big PC cooler extracted from a faulty power supply of PC. After 10 minutes in the sun from the solar collector is out hot air temperatures of 70°C/158°F! The test results have encouraged us to install solar heater on the house as soon as possible.
After completing installation of collector, the outside temperature was -3°C/26°F, and solar collector was blowing out 3 m3/min (3 cubic meters per minute) of warm air. For the home version we have used more powerful fan than the one for testing. Heated air temperature went up to +72°C/162°F. Temperature was measured by digital thermometer. To calculate total heating power of the collector, we took into calculation the air flow and average air temperature on output. Calculated power which DIY solar panels produced, was approximately 1950 W(watts) which is almost 3 HP (3 horsepower)!!!
Considering that the results are quite satisfactory, conclusion is that DIY solar panels are definitely worth making. The collector, at the very least, can be used for additional heating of your home, and it is up to you to calculate and figure out how much money you can save…