Some Solar Air Heater Ideas – Part 1 – See Part 2 And Playlist Of Many Related Videos
Here are some ideas on making a solar air heater out of aluminum soda cans. In particular I make the hole with an awl and a reaming tool such as needle nose pliers (I guess a hard wooden reamer is also possible). The reamed hold should be about the size of the opening on the other side, perhaps the size of a quarter; about 1″ to 1+1/4″ in diameter. The thing is, you want a good/large radiator surface, yet you dont want to impede the flow of the warm/hot air. If you want, since the real lid opening is offset from the center of the can, you may want to take a pair of snips and cut about 1/4 or more inch into the center and bend the metal downwards into the can. Then I show how the cans can be glued with silicone and lined up straight to dry along a straight wall or board(s). An extra bead of silicone around the outide of the joined area would also be good. To paint the cans, be sure they are clean inside and out of any dirt and especially oil since nothing will stick to it including paint. Also, remove the “tabs”. A thin coat of flat (not gloss) black paint on the side exposed (or all sides) to the sun will absorb the heat from the sunlight and transfer it to the warm/hot air column.
The extra “meat” of aluminum (or other metal such as copper or silver) around the hole area acts as a radiator where the flowing air can come in contact with the metal and absorb some extra heat. If the hole is too big this may not be the case, hence this is one advantage of using cans and this method proposed. The only problem with cans is the time and effort to connect and seal them. Still, any heat radiated outside the cans will rise in the glass box and can be ducted with a hole(s) to the output port/pipe to obtain that heat.
I’ve seem some designs where a fan is used to ist/circulate the warm/hot air better. Another option is to have the warm/hot air go into the upper floor of the house while the cooler input air comes from the lower floors. That way a fan is not necessisarily needed since the hot air will move and rise all by itself rather than the air column being forced through before it can adequately be heated. A fan will however help distribute the warm air in the room.
Direct sunlight where the rays are perpendicular (right angle or 90 degrees) to the surface of the collector (here cans) has about 1000W of energy per square meter of area (roughly a square yard of surface area). I estimate that construction costs of a solar air heater is about $100 per square meter (or per 1 Kw of energy output). That amounts to ($100/1000W) = $0.10 or 10 cents per watt. Thats really, really good considering finished solar panels are about $4 to $6 per watt; and also only work when the sun is shining. With solar panels then, 1000W worth of panels would cost $4,000 to $6,000. Roughly out of the question for most people. Still, you should obtain/make a system with at least 1,500W of heat or higher…think of the costs solar panels or the burning of oil or gas would be. Still, for cloudy days and at night, have a backup system(s): gas, oil, coal, wood, electric
With the money saved with solar hot air, you can crank the backup heat up when needed.
To make a solar air heater, your gonna need alot of cans quickly, maby around 100, so ask your friends, neighbors, relatives to put them uncrushed and undented in a bag for the “project” you are gonna make. In the meantime, you can locate some wood, like plywood for the back and some 2×4 (or something) wood for the sides, etc. You’ll need foam, like styrofoam for the insulation and caulking to seal it airtight. Finally, the hardest part is locating a big piece of glass…of which you might have to cut yourself (note pre-tempered glass CANNOT be cut and you must work with it as is if you get that…so your better off usually with basic plate glass), etc.,or design the system around that. I dont recoment the collector be straight up and down when its being used, unless you can tilt it there during the remaining hours of sunlight. A 45 degree tilt from the ground level is a tradeoff position to build/put the collector, unless you design it so that the unit can be tilted at a few angles throughout the day.
It was mentioned by a view that you could sand the metal of the can a bit to make a better joint. If you go that route, don’t breath in any of the aluminum dust, and wash the cans before you glue and paint them.
I realize it is possible to lay some extra insulation (besides in the box of the unit) on the backside of the cans. Perhaps spray-foam, or simply some type of paper, even newspaper possibly; perhaps wet it and place it firmly onto the shape of the cans, and when it dires try to glue it into position firmly. The question is, will it make good contact to provide real insulation.
Be sure to see my new vid with some new info. on this subject. http://www.youtube.com/watch?v=cQJIl-iVSTo
Duration : 0:2:13
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Some Solar Air Heater Ideas - Part 1 - See Part 2 And Playlist Of Many Related Videos
If you don’t like …
If you don’t like the idea of using cans, consider a “flat plate” type of collector. Usually flat-black (thin) coated aluminum or copper, but it’s possible to use just about any black colored material.
If you are building …
If you are building a house/building stucture, you can consider putting a garage on the ground level. Here the outside walls of the garage can have a large solar air (or water). The hot air will naturally rise to/through the lower living floor (the 2nd floor). Also, consider a sun tracking mirror system if you want to illuminate the unit when the suns illumination is not direct. You’ll get a few extra hundred watts.
It would work, but …
It would work, but would be costly for a large system/collector. This is similar to using a fresnel lens also as I mentioned in your other comment.
I haven’t tried …
I haven’t tried that, but it would work under some circumstances. The fresnel lens would have to be bigger than the collecter in order to focus more energy than the collector/cans would without using the fresnel lens. The fresnel lens would also have to be “steered” witht the position of the sun so that it’s focus is on the collector/cans. Mirrors to the left and right of the collector/cans perhaps several inches up to a foot can reflect about a few hundred watts extra on the collector.
..,or even a series …
..,or even a series of magnifying glasses.
have you tried …
have you tried using a fresnel lens to boost the heat energy? several small ones focused on the cans in varying places might give a further added boost. peace
No, I live in PA, …
No, I live in PA, in a medium sized city.
Not to be rude, but …
Not to be rude, but do you live in the back woods somewhere??
The soda cans are …
The soda cans are too small and time consuming, but try using #10 cans – Cut them in half, paint them black, glue them to extruded foam, got the idea??
Go to Lowes …
Go to Lowes department store, they sell building supplies, check out the roofing section for thin rolls of copper flashing.
As an adaptation …
As an adaptation from the solar hot water tech., the tubes can be spaced, perhaps the width of a can, and back surface can have a reflecting material, such a mirror, at the proper angles to reflect that sunlight to the back surface. With glass mirror, the cost might be out of the question, it is however worth it with the solar water heaters since each tube costs more than mirrored glass.
Yes copper is …
Yes copper is expensive, its about 2 cents per solid penny weight I guess. It is possible that copper coated/plated aluminum would be not much more than plain aluminum…which is not cheap when you buy it retail at stores…with aluminum you only get 50cents to a doller a pound recycled, but it cost about 10 bux a pound when you but it new such as sheet/rolled/coiled aluminum. Still a pound can go a long way if its thin (maby 1/32″).A “flat plate” metal collector surface can be made with that.
Ya, I think …
Ya, I think anything-copper is a showstopper right now… just too expensive. The prices on 2″ copper tubes at Home Depot are unreal (the Chinese are really squeezing the market right now.)
I’ll be building a few small solar heaters in the next two weeks to measure how different hole sizes and configurations impact the performance of these units. Kind of looking forward to it… unfortunately the only digicam that I have right now takes video without audio…. might post them anyways.
Thanks for the …
Thanks for the comment. Silicone if fairly sticky, but probably not as sticky when it’s cold out. So your idea will help in that area. It will provide the “glue” more surface area to adhear to and also keep the cans firm during possible vibrations of the unit. I’m not sure about 120 grit sandpaper, maby a little higher number possibly, but no lower. If someone could make cheap aluminum or copper tubes like this we would not have to make them this way.
you can help the …
you can help the silicon seal by roughing up the egdes just a little bit with some gritty sandpaper, 120 would be fine…helps the silicon grip/adhere against the surface. I suppose it’s not entirely necessary in a solar heater but..
As with all my vids …
As with all my vids or any vids on YouTube be sure to read the Video’s text area that can contain additional information not in the video.