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soda can passive hot air panel, worth the hassle?

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  • #46
    Pay

    Originally posted by russ View Post
    Don't get suckered in to paying for a design - they are available for free on the net.

    Polycarbonate has reasonably good light transmission characteristics and some formulations are UV resistant - the mfg tells you this.
    Surprising the things people try to charge for that are readily available free.

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    • #47
      Holy Cow!

      Originally posted by Denver Dave View Post
      I did a test 2 years ago with a 2 ft x 2 ft x 1 inch silver covered foam board and about 50 or so beer / pop cans painted black with holes punched in the bottoms. I wrapped the entire thing in window shrink wrap and cut air slits in the top and bottom for the air.

      On fairly cold days in Colorado, but with good sun, and calm wind, the panel put out air at the top at 180 degrees.
      180 degrees on a cold day? That is awesome!
      I hope you didn't have anything to do with the "wildfires" there!

      Comment


      • #48
        test

        Originally posted by SolarHeater View Post
        Hi guys, it's Eric and I also built a soda can and a downspout style heater. I should say, I started the soda can one. But I gave up after immediately insisting there had to be a better way. I wasn't yet sure how, but I knew there was a better design to be made. The second time around, I skipped the soda cans altogether and built a downspout style plenum. I still have this heater and it works great. However, I'd have a hard time believing anyone else would like to go through that process again or be able to follow it easily. I certainly wouldn't want to again. So again, I went back to the drawing board.

        I used to be a metal fabricator for an industrial oven company as well as another large machine manufacturer so it was not a real problem for me to build any style heater, but, after building one and a quarter solar heaters similar to what I found on Youtube, I decided that the easiest and SAFEST way to build an efficient heat-capturing plenum was to build it like we did at the oven company. My problem was, I no longer had access to a sheet metal sheer (cutter), a sheet metal break (bender), welders, and etc. and neither do most homeowners. So I set out to design a homeowner-friendly solar heater that could be reproduced easily with easy to follow instructions and without all the expensive, dangerous tools and without the time consuming hunt all over town for materials.

        Then the ideas came to me for the perfect choice of materials that were readily available at the local building centers. All the materials should be able to be picked up in one stop. Because stock of certain materials may differ from store to store, you can ask your local store to order an item if not in stock.

        Safety was a major concern. I cringed when I watched folks on Youtube drilling cans with hole saws and drill presses while wearing gloves (a big no-no), loose-fitting gloves no less! This is very dangerous and great way break one's wrist or fingers or worse. The factory I spoke of had an accident where a female worker got her glove caught in a drill press and it nearly killed her. So skip the gloves when using power drills. Ok, and the average homeowner isn't going to be too keen on cutting a zillion cans (or 101) as in the video in this thread. Although I love his ingenuity and his heater sure heats well, I'd not want to build it that way for sake of speed, safety, and other factors.

        My manual teaches my design that is wood-free, can-free and glass-free. Wood is heavy, expensive, isn't weather resistant, and for many, dangerous to saw. So I decided right away that there would be no wood in my solar heater design.

        Although beer and soda cans might become the only materials left to scavenge from the rubble in coming years (I hope not), today the average homeowner's neighbors really aren't going to be very excited to stare at that "beer can sculpture" you built across the street for the next 30 years. If you're up in the north woods, you might be fine. But in the city, no way. So I wanted the design to look professional "factory" as my former boss liked to call it. So cans and wood boxes are out, for now.

        Okay, glass was the next obstacle. For the first two heaters I made, I scavenged for glass, I searched on Craigslist for it, and ended up paying $50 for a dual pane patio slider door (super duper heavy!), and had to dig the second out of a 40 yard dumpster I happened to see near my home. Both had to be taken apart and carefully moved around. A huge pain. Again, the average homeowner isn't going to want to hunt for glass like this and then have to "build to" the size of the glass they end up with. And how easy is it to hang a 200 plus lb. box on one's home or move to a new home someday?

        My solution to glass was a super light weight dual-walled 4'x8' polycarbonate panel readily available for just $39. It's surprisingly inexpensive at less than half the price of a 3'x7' piece of plexiglass that's $99 at the same store. The polycarbonate panel is 'bomber' and I think it says something like 100 times stronger than glass on the package. You can throw a baseball at it with all your might and it just bounces off. Plus, it's two layers and offers an insulating value and super rigidity to the heater itself. And it looks great from across the street!

        Because my design is built in the same manner as a typical oven plenum, there aren't a whole lot of parts to it and therefore the heater can be built much faster, safer and much much easier. Plus, there's very little mess afterward. No sawdust or foam particles all over the place. My first two heaters destroyed the entire garage!

        My heater is made from only light weight parts you pick up at the store. Everything you need fits right on those lumber carts you are certainly familiar with. My manual lists on one page everything you need to pick up from one store (depending on their stock of course), remember you can order all of the parts to your one location. I also show you where to order a [B]computer-controlled fan controller[/B] that is specifically designed for solar heaters. The controller reads the internal temperature of the solar heater and slows the fan down if a cloud passes in front of the heater, speeds it up when the sun is strong, and shuts off the fan when the sun is not shining. The fan comes with a sleek inlet and outlet grate with a filter so it looks like any other air vent in your home, and keeps the interior of your heater and your home filtered. The other fan I show you is about $18 and is available at the same building store and it certainly does the job. Both can be run with a solar panel if you want to or need to be off-grid. I show you my simple set up and everything is available at the one store.

        The end result is a heater you can pick up and carry by yourself, bring along on your next RV trip or connect to the ice fishing shack. It's rock, baseball and hail-resistant, and it looks like a standard skylight or window when completed because the flashing you'll use is powder-coated and looks fantastic. . It will be easier to build than the soda can and/or downspout styles. And when it hails, you won't be biting your fingernails praying all your hard work won't be in a million pieces.

        How hot does it get? Last winter during my testing in Minnesota, I had 22.5 degree F outside air pumping directly into the bottom of the heater (normally, you'll pump floor level air from inside your home outside and into the heater), the air coming out of the heater during the test held at 155 degrees F. That's 15 degrees hotter than your standard furnace.

        During the fall, I tested it with 55 degree air pumping directly into it and the output was over 220 degrees F as it buried the needle on the meat thermometer. Too hot to even touch. Amazing.

        Don't forget, you can easily connect yours to the inlet on the back of your clothes dryer all year long, so build one for your dryer as well. (Although you do not have to alter your dryer at all, do ensure that your warranty will not be adversely affected before taking this step). We're installing one to the clothes dryer in Phoenix at the moment. I'm simply taping a turkey basting tray over the inlet on the back of the dryer and running the tube into it. So no permanent alteration. No more sending air conditioned air into the back of the dryer to be reheated and sent outside! How ridiculous is that when you think about it? Also, this heater has been sitting in the Phoenix sun for 4 months now and the polycarbonate panel still looks great and has not yellowed or cracked whatsoever. So I am confident that this design will last for many years. I hope you will want to build it for your home.
        Mmmmm
        Last edited by inetdog; 11-05-2014, 09:36 PM. Reason: Removed dead attachment link.

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        • #49
          I really like the solar can heater idea. Something like this would be outstanding if used in conjunction with a thermal mass battery to provide heat overnight and not just throughout the day. Awesome stuff.

          Comment


          • #50
            Originally posted by RoboSamurai View Post
            I really like the solar can heater idea. Something like this would be outstanding if used in conjunction with a thermal mass battery to provide heat overnight and not just throughout the day. Awesome stuff.
            Yes, as long at the collector produces enough heat to allow charging up the thermal mass while still producing comfortable temperatures during the day.
            Thermal mass is particularly useful in a passive collector in which the incoming sunlight directly hits the thermal mass.
            Trying to link thermal mass to a soda can heater with moving air may not be worth the effort.
            SunnyBoy 3000 US, 18 BP Solar 175B panels.

            Comment


            • #51
              sizing a system.

              Does anybody have good information on how to best size a solar heater?

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              • #52
                Originally posted by drubru1969 View Post
                Does anybody have good information on how to best size a solar heater?
                Builditsolar.com

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                • #53
                  Sizing solar heater

                  Originally posted by drubru1969 View Post
                  Does anybody have good information on how to best size a solar heater?
                  7 Tubes of 6 meters gives you on a sunny winter day (at noon) +65°C compared with the outside temperature.

                  https://www.youtube.com/watch?v=8onkXvkQWIQ
                  https://www.youtube.com/watch?v=h3mr3X-5e_I

                  My design has 3 boxes in serial. Every box adds approx. +22°C
                  I'm planning to build another one with one more tube of 6m and the possibility to change the inlet:
                  Or cold air from the outside, or warm air from inside my home.
                  If I use for example the air from inside my home in winter, and heat it up in the air can heater box, than the outlet will be approx 80°C.
                  I use 9 fans already, so the heat transfer is fast. The power consumption of the fans and temperature controller is 30W.

                  Regards.
                  Bart

                  Comment


                  • #54
                    I had never heard of this before today. Interesting concept. Did a google search and came up with this guy that tested both a soda can collector and a screen collector then compared the two. apparently the screen collector came out slightly ahead:

                    http://www.builditsolar.com/Experime...anVsScreen.htm

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                    • #55
                      Much better than cans

                      Check out this post I found on simplysolar.com It's a little work but less than a popcan. The post is testing a new idea using a product called "Cinefoil" cinefoil is used in photography to block and shape light.

                      [B]Mod note - Webroot shows the site as unsafe.[/B]

                      [COLOR="#B22222"] -- Mod Note: Currently I get the home page with the banner "The domain simplysolar.com is for sale. To purchase, call Afternic.com at +1 339-222-5147 or 866-836-6791. Click here for more details."
                      Looks like they did not pay their registration bill but for now the site servers are still operating. Either they have a very careless web admin or the site has gone under. There may not be anything wrong with the ideas, but any links on the site could be suspect. [/COLOR]
                      Last edited by inetdog; 08-26-2014, 05:04 AM.

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                      • #56
                        Old thread, but my 2 cents: the whole point of soda cans is that it can be made in 3rd world countries by poor people who have nothing but time on their hands to collect the cans and build the thing all out of scrap.

                        I plan to make one for the hell of it and try to pipe it into my package Heat pump on my roof to see what happens...

                        I won't be using cans, but probably aluminum downspout or something like that.
                        House-Sun Earth Hot Water.
                        RV-390W Kyocera, Kid.

                        Comment


                        • #57
                          Originally posted by ZoNiE View Post
                          I plan to make one for the hell of it and try to pipe it into my package Heat pump on my roof to see what happens...
                          Two comments:

                          1. The downspout, unlike the cans with partial top or bottom stirring up the airflow, will have smooth non-turbulent airflow and so may not transfer heat as well.

                          2. Except for the fact that it avoids the need for building ducting going into the heated room(s), piping warmed air into the input side of a heat pump is, thermodynamically, a wasteful process. The extra energy that goes into the room will be less than if you ducted the warmed air in directly, and you will still have the operating power requirement of the heat pump.
                          SunnyBoy 3000 US, 18 BP Solar 175B panels.

                          Comment


                          • #58
                            Originally posted by ZoNiE View Post
                            Old thread, but my 2 cents: the whole point of soda cans is that it can be made in 3rd world countries by poor people who have nothing but time on their hands to collect the cans and build the thing all out of scrap.

                            I plan to make one for the hell of it and try to pipe it into my package Heat pump on my roof to see what happens...

                            I won't be using cans, but probably aluminum downspout or something like that.
                            Compare the airflow through the heat pump with the flow through the air heater - nothing gonna happen.

                            Cans vs tube is not at all a 3rd world thing - just a better idea.
                            [SIGPIC][/SIGPIC]

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                            • #59
                              Originally posted by russ View Post
                              Compare the airflow through the heat pump with the flow through the air heater - nothing gonna happen.

                              Cans vs tube is not at all a 3rd world thing - just a better idea.
                              The whole can thing makes it free in 3rd world countries... Just like the big water bottle in the roof making a skylight, and other similar oddities.

                              We have variable speed fans on the heat pumps, and keep them running on very, very low speed all the time (I know, wasteful) to keep the coils dry in summer, and always have a little airflow in the house. Helps with my wife's allergies. I figured, let it draw some warmed air through one or two of these things, and it may keep the bedrooms warmer during the day without firing up the compressor. Just have to plumb it so that the draw into the heat box is from it's own port in the house somewhere so as not to have a static drop across the coil in the Heat Pump. (It would effectively suck from both ends).
                              House-Sun Earth Hot Water.
                              RV-390W Kyocera, Kid.

                              Comment


                              • #60
                                Originally posted by ZoNiE View Post
                                The whole can thing makes it free in 3rd world countries... Just like the big water bottle in the roof making a skylight, and other similar oddities.
                                I have been in a lot of 3rd world countries over the years and have yet to see the water bottle in the roof thing applied. That is really at the bottom of the ladder.

                                The turbulent air flow in the tube (cans) is important. One can always make up some type of insert to create the same condition in a straight tube. Fairly common in heat recovery systems.
                                [SIGPIC][/SIGPIC]

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