DIY Solar Air Heater Part #7
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- Опубліковано 21 лют 2021
- With my first Solar Air Heater installed and producing real heat, I wanted to quickly install another, and double the BTUs I’m bringing in.
Let’s tweak the design and see if I can make it even better…
This is my last video on Solar Air Heaters, as I have another project in the wings that I’m getting ready to bite into.
I do want to thank everyone for your feedback and support over the last few years.
I am really interested in hearing how others are making out using alternative materials for conduction.
Cheers
Thank you for putting the effort into educating the rest of us with very clear explanations of the theory as well as the practice of this project. Your series stands well above the crowd in its usefulness to the rest of us. Thank you so very much for "open-sourcing" your knowledge and experience.
Thanks for the feedback. It has been a great learning experience for me, and posting my experiences on UA-cam has opened up a dialog with people all over the world with likeminded individuals, many with much more experience in this space than I. I am very thankful for their comments and suggestions. My system is now a year old, and I just passed 1,000 hours of free heat according to my Hobbs meter.
Interesting result. Have you tried running the first design with 2 fans and the second design with 1 fan? That would reveal the effect of that variable. If the fan variable is minimal, the output from the second design is so much higher that it might be worth replacing my the cans in the first heater with cans of the second design. I also wonder if you could fine tune the design by testing various numbers of baffles before you reseal the plexiglass with silicone sealant.
Since I'm thinking of installing such a unit on my garage, it's a great informative video.
Good morning, thanks for the short note. We have been using this system for a few years now, and although I’m thankful every morning with the warmth it brings into the hangar, there is one thing I would do differently if I was to do it over. I would use glass instead of Plexiglas. My plexiglass is not standing up over time. Dozens of hairline cracks are forming. That is about the only additional peace of information that I can share that I think might be valuable to others. Look for some second-hand windows and size your unit accordingly.
congratulations, it is the best tutorial I have seen
Hey thanks for the feedback. Keep in mind this is all trial and error. Fun project though, and it takes the edge off what would otherwise be a cold hangar. Cheers
Your calcs at 5:52 I think one is based on btu s and one on watts. I just cross multiplied and found this out. No biggie. So I forgot what the area of your heaters are in terms of meters squared.. J read somewhere that only about 1000 w/m2 actually reaches the ground due to atmosphere diffusion, etc... So Id like to know the percent conversion of your second heater vs maximum available(based on your square area) If better than 17 percent(solar pv) then that makes the case that solar pv is less efficient than solar air heater. (Dont know if this would hold for cloudy conditions though).If your conversion percent is mis 60 s then it rivals that of direct solar heated water. Also what about direct comparison's to commercial units ?
Also you could test you wind meter by measuring it directly thru a dryer vent ans comparing to the 151 cfm specs and adjust your readings accordingly? Percent variation
Thank you for sharing the info from your tests and experiences gained!
Great stuff, thanks for the effort in documenting your findings..hope the next project is aviation related.
Thank you for posting this in depth review and update! I'm going to go back and watch the previous videos to learn how to make one of there.
Well done a brilliant investigation with great results.
Very good and educational video, with some great CAD animations. 👍
Thanks. I watched your entire series, im going to try this idea.
The information you provided is so helpful. Thank you so much for this video.
Thank you very much for all your info and design work.
Glad you enjoyed it.
Thank you for taking the time to comment
Much appreciated.
Dwayne
Fantastic video Dwayne, thank you so much for taking the time to share all your knowledge and experience with us, it is very useful to those like me, trying to build my first unit!
Sorry, I somehow missed this comment. My apologies. Wish you luck with your build.
Dwayne
Thank you for this great video. Will be building one unit following your ideas, with some mods that i have in my head.
Got some cool ideas from your video.
Thank you
Please share what you come up with. cheers
Very interesting Playlist. Thanks for sharing it.
great video
I am collecting scrap copper wire to try as a weaved heat gathering grill to try something similar to the aluminum screen solar heaters i have seen a lot of.
I cannot get copper cans to compare the difference in metal performance so I guess this might show some results.
Only restrictions I have now are health and energy but I am really keen to give this a try for a new workshop, studio I am building here in the Shropshire Hills in the UK.
Thanks for setting our brains in gear.
Thanks for Sharing. I'd love to hear how you make out. Dwayne
Bravo! This video had the missing knowledge I needed so badly.
Wow! Thanks for sharing!
Thangs for the feedback
Cheers
ever best video great thx
Great videos,great ideas, your great and awesome channel.
Thanks for the feedback. Very kind
Awesome thank you for your time
That's very kind. You're welcome.
Fantastic video 👍
thank you
Thanks a lot to share your experience! Greetings from Argentina!
Argentina, hello from Canada ! Thanks for your feedback. Dwayne
very nice and informative video thank you for your insights
Thank you, glad you enjoyed it. I appreciate the feedback.
Dwayne
Thank you for actually taking a scientific approach to this. Where so many others have done videos with a similar-ish setup. Very few have taken time to do updates on performances or improvements that they have done on their particular setup. At least with the information that you present I can now be more sure of the heater and what to expect from it. Good luck with your next venture.
Thank you for the feedback - very kind, thank you.
Dwayne
You are a walking talking text book. Now I've got to listen to you about 10 more times. Amazing video. Great info.
Thank you , very nice video ,the best tutorial .
thanks for the feed back Petar
Great informative video. May I suggest some potential improvements? Place sun reflectors on the sides and bottom as a solar oven is built. And since air is expanded when heated creating more mass, it may be bottle necking with too much mass to leave the heated chamber. If you where to maybe install 2 holes at the top and one on the bottom, you may not need a fan. I would believe that the heat will go with the least amount of resistance. Maybe even 3 or 4 holes with a flexible exit door on top so the heat pushes the door open to escape into your area to be heated and closes when it's not heated. Thank you for doing the work and great presentation with your wonderful graphics. I need to build one and I have limited amount of time and money to do so, I need to get this right the first time around. That's why I care so much . Responding to my comment would be greatly appreciated. Thank you again.
So much of this work is theory and testing. You have a number of good ideas here, but they are not tested. From your list, I cannot comment on what works and what doesn’t. I’m not sure that “getting it right the first time around” is possible. I’m sure whatever you build you will learn from it, and your second version will be better. if you follow my videos from 1-6 you will see that my earlier designs didn’t work at all, and I was following the advice of those before me. In my last video, I took a unit that was working and made one even better. I suspect there is no end to that. Suggest starting with something similar to mine, try one or two of your ideas, and see if you can make it better, then share with me and others. We all learn from this. Best of luck. Cheers.
congrats on the proper explanation! so many ppl get it wrong.
Thank you for sharing your valuable experiences, I now will have a go at making one of my own using your findings.
Glad you enjoyed it. Thank you for the short note.
Cheers
Very cool! Would be interested to see if you add a second fan to the first heater to see how that affects anything. I do suspect the outer tubes don't get the same movement of air as the central ones, so your turbulence/restrictor probably distributes the flow between all the channels better.
Great series. I think what makes it is the logic behind the decisions. Not always right but prototypes never are, always improved second time round. That thought process nailed it.
Great learning experience
What a great series and thorough explanation of the variables and how they impact design consideration. You mentioned earlier in the video that keeping the temperature differential low would increase efficiency because less heat would be reradiated for conducted back out the outdoor collectors. And that makes total sense. The sooner you get that heat inside the less chance it has to get lost outside. So what about drastically increasing airflow with much more powerful fans? Also more powerful fans might increase turbulence thereby increasing efficiency as well.
Thank you.
You probably spent too much time making these for what you get out if it, but the information really helps others.
I made plans for a screen version to heat one room to start. My idea includes a metal roof panel at the base, 3-5 layers of screening, and laying horizontally due to location, but this will also give a pass down and back.
Thank you for this idea, i am planning of using your design in my paddy drying project. Thanks a lot..from philippines..
Good luck with your project
I've been looking at a few of these videos as the concept is pretty interesting. I've been over charged for over a year for gas due to a sub supplier luring me in with a low initial rate, and Im looking to reducing my home and garage heating cost to offset that mistake. Plus it's just better overall anyway, which is my real long term motivator.
Unfortunately for this winter I should just keep working on my main business. But if I do one of these DIY panels, your videos have been invaluable! I would have had to do the same things, and ended up with 1 sub par panel. Your staggered airflow was also a great idea, and quite obvious in hindsight.
It REALLY bothered me all these people using 6-10w computer fans that have low airflow trying to move so many BTU's of heat! Your PC uses more fans for less heat! And as you noticed, yeah the high temps seem impressive but efficiency is lost. Although your higher airflow and same exhaust temp is VERY interesting. Have you added a second fan to the first panel and compared data? That'd be the first thing I did!
Honestly that is unreal , i was just starting MY FIRST build when i saw your video purely by accident ( surfing ). I cant wait to use your idea, but i have an idea for you if you want to try it one more time. I ride motorcycles and in the old days you would take off the muffler and install a baffle into the header pipe to change the sound. They are an X configuration yet twisted which would cause the air to twist like in a barrel of a gun. Just a thought but i think i am going to try it myself. I will let you know off my results when i finish it. But it might take a long tome, i work 6 / 10 hour days and little time for myself. Thank you for the information and the inspiration. the best video i have seen on this subject ever. Patrick
Patrick, nice to hear from you.
I love your twisted “X” idea. I have another idea for you to try. A fellow in Mongolia was suggesting that I try stuffing crumpled metal screen (screen door material) into a metal downspout. Apparently in provides phenomenal conduction, with minimal restriction to airflow.
Good luck on your build, and keep me in the loop with your progress
Cheers
Dwayne
Good job...
Thanks, I am going to build one in SK
Urobil si ?
Loved this series - if you want to make it produce even more heat - shine mirrors on it - 3 or 4 mirrors and it will get seriously hot - for the price of a couple of mirrors.
I’ve always wondered if a Fresnel lens cover, even with the focal length off, would work well to capture more heat?
Hi everyone
Just a quick update. My two solar air heaters have been capturing heat now for almost 10 months. The Hobbs meter has recorded over 1,000 hours of run time.
What have I changed in the last year? Well, one modification was needed. During the summer months, the Plexiglas got softer in the heat and lifted off of the frame slightly between the screws. Therefore I added fasteners every6-8 inches, to secure the Plexiglas. That is the only change I have done.
Others at the airport still comment on these units. It was minus 7C a couple of days back, and the units were bringing in a steady 30+C heat. That still amazes me, and those that come to visit on sunny days.
A year later - would I do this all over again? YES! And I would try a different design. As I have shared all along this has largely been an experiment for me. I have received positive feedback and kind suggestions from all over the world. What I have learned, is that I’m not doing anything new here. All of us are building on the success of others.
My largest viewing audience (by far) is not Canada or the United States, its Mongolia. Over 35% of all of my viewers are from Mongolia. And having received so many comments and suggestions from people that live there, I have come to realize they are WAY ahead of us in this space.
Thanks to everyone for your comments and questions, and I apologize for not being able to answer everyone.
Dwayne
OMG, Mongolia... who would have thought that? Good for them!
Thank you for sharing your work. Would you share one or two of these ideas that you might try if you were to build another heater?
Although I currently have no plans to build another unit, I think if I was, I would test metal screen material for a screen door. Painted flat black and maybe 3-5 layers of screen. I think that would be a worthwhile test. Some feedback I have received from Mongolia suggests that metal screen might be a good choice as well.
Cheers
@@annnonomys3132
@@LifeIsShortDIY Thanks
All the great work being done on solar water heaters is in undeveloped countries. The units are far cheaper and lots and lots of people use them. Maybe we should rethink that term undeveloped.
Super charging the air by recycling inside the collector by having half on initial draw and half on preheated draw by using dividers in the ends to redirect the air but you would then have both vents on the same end.
I think the thermal collector you made is the best on the internet
I would like to make a similar model and I want to add a pump, a sprayer and a small container of water to turn into an air cooler
I would like to hear advice based on your experience
Hey thank you for the comments and feedback. Wow I love your idea. As far as advice, I don’t really have any. Everything I have done in this field I have shared. One point I can add is I have received a great deal of feedback from people in Mongolia. From these discussions I can share that I believe they have a lot more experience in this space than we do in north America. One of the suggestions I received was to try metal screen instead of pop cans. I have not experimented with that material at all, but if I had the time, and I don’t right now as I’m wrapped up in a van conversion project, I would build my next solar air heater using three flat-black painted metal screens to pass the air through. Could be better, could be worse - don’t know. But less work to build than out of pop cans so it wouldn't be too hard to test.
I am very interested in your pump, sprayer, air cooler idea. Please keep me in the loop on that. I would very much like to hear how you make out there.
Cheers
Dwayne
With such long columns of cans, I did wonder if the box should be divided into two chambers to reduce airflow restriction. However, your second design is working so well that it seems to have a good combination of flow and turbulence.
What I have learned is that it is a bit of a balancing act. The second unit is pretty well balanced. I’m looking forward to measuring the best it delivers on a perfect day. It’s not pointed directly at the sun, but it has good exposure. If I was to do further testing on this unit, and I’m not, I would try 5/8” holes instead of ½”.
What about instead of wide open and four wholes cut one large whole im every can smaller than wide open so your left with a fin all the way around the inner circumference of the tube?
You mentioned at some point that this system would not really be able to fully replace conventional heating. Well that might be true in colder climates, in temperate zones, I'm in Southern California, believe it or not we also heat our homes for about five six months per year. Of course the outside temperature differential is not nearly so great, so a few units like this could probably keep a house comfortable enough to be used as a sole heater probably 80% of time. You would simply have to do most of your heating during daylight hours obviously. You might run a heat source like a mini split heat pump for a few hours at night and on very dark overcast days. Just huge energy savings. Not to mention how unbelievably simple these units are. Ought to be required a new construction.
At 7:00 I used the can on the right with four holes. Then to get the spiral effect I put a rod into the hole and twist it so that the hole has a depression on one side and a lift on the other.
This causes the spiralling in the can.
The can with the four holes did not work for me. You will see that in video 5. Cheers
this is a very nice series of videos. I learned a lot...
unfortunately there is a deposit system for beverage cans in Germany. sSo they're not so easy to get for free... therefore i thought about alternatives and I came up with the idea of using corrugated sheet metal allowing upward air flow making construction of such a thing much faster than assembling hundreds of cans!!!
morover adjusting the angle of you system towards the sundlight making the sunrays hitting the system at an angle of as close to 90° as possible will probably give you more heat ...
Furthermore you could insulate the system as your aluminum case will loose a lot of heat towards the outside. use glas insted of plexiglas as it insulates much better.
and one thing i was asking myself.... does the interior has to be metal?
Hello Dwayne, Thank you for the excellent detail in your videos on your solar air heaters. I like the aesthetics of your design and I feel like the effort you put into using aluminum gives them a nice architectural look.
I have a thought on your efficiency comparison you did at the end of this video. It was clear your were both surprised AND a bit skeptical of your results, and I think I might have a theory as to why you saw the efficiency difference you did.
Obviously, the more air flow you can muster the more efficient the panel will be, as the differential temperature between what is going up the tubes and the cold outside air would be less, essentially reducing the heat loss out the front of the panel. That alone does not explain why you had an increase in BOTH the airflow CFM and the temperature. My theory on this is that while I'm sure you did an excelent job air sealing your units, it can be very difficult to get a perfect seal. If you have only one fan sucking air into your building, any small gaps at all would allow cold outside air into the air stream. While on the second unit, you had a more balanced air flow by blowing in and sucking out. The pressure inside the unit would be closer to ambient, resulting in less air leakage. If you are thinking the baffle design alone accounts for the efficiency you saw, I would suggest a fairly simple modification to your first unit to test this. Simply place a second fan on it as well, to replicate the same fan setup you have on panel 2. I would even hazzard a guess that with a double fan setup, panel one might even exceed the BTU's gained from panel 2, but I bet you would at least see similar results.
If you do decide to try two fans on the first panel, I would LOVE to see what the results would be of that one small change.
Keep up the good work, your videos are well made!
Excellent analysis. I like the way you think, and agree with you completely. That is a real possibility.
@@LifeIsShortDIY Wouldn't it make more sense to suck in warmer air from inside the building to heat up, rather than cold air from outside of the building? Cold inside air goes thru the collector to get warmed up and comes out up top. This leads me to another potential design improvement, wouldn't it make sense to force the air out lower since heat rises?
@@jeremyeverett6186 Both units suck in warm air from inside. There is no outside air introduced to the system. The second unit was designed from the start to force air out the bottom.
Regards
Great video, Dwayne. Thanks! This addressed the biggest outstanding question I had after your first six videos on this subject (essentially, how much turbulence do you actually need, and at what point does the additional turbulence become counter-productive?). I have a follow-up question, though. In an earlier video, you briefly discussed alternative materials. At the time, you preferred the pop-can design over for example a downspout design, because you felt you needed the added turbulence provided by the cans with the holes in the bottoms. Now that you have gotten rid of most of those "baffles", and only have one or two in each column of cans, wouldn't a downspout design with a few baffles inserted in the middle produce the same results, with less work (effort of cutting and gluing all those cans together)?
Matt, That’s a good question, and I’m looking forward to Dwayne answer. I do wish I could find ‘ down spouts ‘ as thin skinned as pop cans. Seems like that thinness is beneficial. Do you disagree ?
Matthew, great question. From others, on the web, I have learned that pop cans are about 16% better at conduction over downspouts, due to the thinness of the material. As I understand it, because the metal is so thin, it heats up in less time. I have not validated this.
One could argue that the thicker metal that downspouts are made from may retain their heat longer, and I think that too is a good argument. I have no experience with downspouts; I have just been building on the knowledge of others. Additionally, the National Research Council of Canada also had some favorable results using pop cans.
So, to answer your question, I used the pop can material for its conduction properties.
FYI, on this last unit, I used four ½” holes on each baffle. If I was to do it again, I would try 5/8” or ¾”. Ideally, I would like to get the internal chambers slightly cooler. Less resistance would give me a few more CFM, which would cool the chamber just a pinch more making it as efficient as possible.
It really is a balancing act.
Cheers
@@dwayneprice956 Thanks, Dwayne. I thought that might be the reasoning!
@@dwayneprice956 It is more likely the built in restriction at the end of every can is what increases the efficiency for the most part. Also the cans have a larger surface area for a given heater size.
I built one with gutter downspouts and really like the design and ease of build, it's brand new so I'm still taking note of it's effectiveness but it works well. I'm blowing in 118°F air inside my house with about a ten foot run overall of ductwork from outside to inside in my kitchen with insulated ductwork (fiberglass wrapped with aluminum foil). I've noted that there is a 30°F drop in temps from inside the box with fan on to the final exit duct hole. No fan on, the inside box gets over 200°F-wish that could be the end result.😀 All of the air flow takes place within my gutters and the interior box is lined back and sides with 1” polystyrene foam board (shiny backing, not the pink stuff) and everything painted with flat black high heat paint, no odor whatsoever from the exit air. A previous one with non high heat paint and air circulating freely inside the box stunk badly and never ever went away! I want to build another project one day using coiled PEX tubing filled with water and glycerol (non toxic anti-freeze) that would circulate with a pump and go through an old fashioned steam radiator type of thing. I think the hot water holding on to more heat than air might be awesome! This link is what I based my solar box design on, pretty clever I thought and I like it.👍 ua-cam.com/video/PSHyCYZQTYc/v-deo.html
Surface area is one of the prime factors in heat transfer, I think an accordion fold of your sheet metal would produce massive surface area to transfer heat, but still allow very good flow characteristics. Think of 1" wide channels. Air could flow above or below the design.
Do you have a picture or a sketch to share your idea?
i think a even bigger fan (just one) that you can adjust the speed would improve your numbers. Also to have inlet and outlet in the lower part and let the air flow up and turn using half of the cans up and the other half down to the outlet.
consider the heat from "compressing" the air when backpressure is higher , that extra heat is provided by the AC outlet driving the fans.
Very well explained video, thank you a lot.
I was interested in finding how to build efficient one.
I wonder if, when possible, it wouldn't be beneficial to install it inside home or flat instead of outside?
Sitcked to windows glasses.
There will be no outside cold air effects or less effective cold effects from the inside windows glasses.
Breanne, all good ideas. For us, this whole thing has been a wonderfully rewarding experiment. We were in the hangar today, and were pleased to see 37C air coming in on sunny blustery day. Very pleased.
Cheers
Dwayne
I'd like to make a couple of suggestions. First I used a hole saw and drill press to cut out both ends of every can to maximize airflow. That way your heat depends on the length of the rows. More cans, higher temps. Second, consider a plenum design. You have a plenum the length and width of the heater below an insulating layer under the cans. Now your air flow brings cool air into the unit at the top into the lower plenum and it flows down to the bottom of the unit and then convection lifts the hot air up while drawing cool air back down in a loop. Mine flow in and out from an extension on the top of the unit into a window with the plenum and output both open at the window interior. To increase your heat gain you need to angle the unit so it's a 90 degree angle to the sun during the winter. You can get that data online and adjust your unit on a stand to get the right angle. My unit raises inside temps from forty to fifty degrees and has a good amount of convection air flow without a fan. I typically get a good heat output for around six hours per day.
can you share more info in some video ? i d like to see it
@@radovanbucko4973 On you tube look up renewable solar air heater. You'll get a video on a flat panel collector solar heater with a breakdown of it. Then instead of the flat panel collector you install your beer can heater collector. MIne is made out of half inch styrofoam, eight feet long with a couple of feet angled off at the top to fit into a window like a window ac unit. Instead of expensive glass I used a 2x8' corrugated green house panel. Bottom and sides are two layers of foam for strength. Plenum top is one layer with the cans resting on top of it. Unit is put together with construction adhesive and aluminum duct tape.
@@71160000ua-cam.com/video/VtR5ypJ3PGU/v-deo.htmlsi=wgMaAV7bgMiVJlBv
Hello Dwayne, thanks for your video, very interesting. If I'm correct, the original design has one fan and the second design with air turbulence has two. What is the difference with only one fan for both I.e the true difference between turbulent and non turbulent air? Cheers
Thanks !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Very nice work. Than you for sharing everything. Thinking about your ideas for increasing airflow and heat transfer, what if, instead of using 9 parallel columns of stacked pop cans, you were to use one continuous flexible aluminum duct (such as a 4-inch flexible duct that is used on dryer vents), painted flat black. Cooler air is pushed into the flexible duct at the bottom of the unit, and then moves in a serpentine flow from the bottom to the top of the unit. The air is increasingly heated as it moves through the long duct, and the 4-inch diameter allows a large flow rate. What do you think? Thanks
I think there are a number of opportunities to explore. Listening to few in Mongolia, a few have experience good success using metal screen as the media. Something else to consider. Best regards.
Thank you for the education. I wonder if small individual fans on the bottom of each column could increase air flow?
Also could redirecting air up and down the columns (3 times) effectively increase temperatures if the airflow was sufficient ?
So much to learn from you!
Thank you for your comments.
Very kind of you to refer to my ramblings as education. This project for me was a wonderful experiment. To be honest, I believe I have learned more from those watching our UA-cam channel, as many have shared with us their experiences and ideas in this space.
I have received numerous comments and suggestions regarding the recirculating of air two or three times, and I can’t say definitively what the outcome would be. However, I know when we start to explore these paths it is important to remind ourselves that these units don’t produce heat, they capture it.
This is really an exercise in maximizing conduction. Each square meter of sunlight only produces approximately 1380 watts of energy, and I believe that if our experiments remain focused on thermal conduction, maximizing heat transfer from hotter to colder, we will continue to improve our designs.
Chatting with a fellow UA-camr from Mongolia, the gentlemen suggested using rain downspouts filled with crumpled metal screen. Apparently that design has tremendous conduction properties.
I am currently 100% engaged in another project, but if I was to build a third unit, I think I would experiment in that space and see how it compares with my first two designs.
Cheers
Dwayne
Hello big fan. I'm going to build a solar panel this month so I'm wondering if you have any new tips and maybe solutions to add to your BEST Solars videos? I find it very useful and want to create my own. Please, more information will be very much helpful. Thanks
Hi there, thanks for the note. Well we have been using our unit for a couple of years now, and I do have a few comments, so thanks for asking.
The electric fans that we purchased are working really well, no bearing noise, or any negative vibrations. They have a couple of thousand hours on them, and they are doing well.
The Plexiglas is another story. On one of our units hairline cracks have formed starting at some of the screw holes. I have stop-drilled these cracks with no success, they seem to be continuing. I’m not sure why this has happened, as it has only happened to one of the units. When I installed the Plexiglas the holes through the Plexiglas were purposely larger than the shank of the screw; this was to ensure there was no undue pressure on the Plexiglas, and to prevent exactly what we are experiencing. I installed both using exactly the same technique. I can say that the second unit, the one with no cracks, has twice the number of screws securing the plexy, possibly a screw every 6-8”. In any event, no cracks in this unit.
I have not replaced the Plexiglas yet, and don’t have any plans to do so until it is absolutely necessary.
So a takeaway for me that might apply to you is to explore glass and possibly make use of used or recycled glass. I.e. get your hands on second-hand glass, and make your heater unit “that” size. I suggest second-hand, to keep costs as low as possible.
I think that’s all I have to add. On a sunny winter day, when it is -18°C or 0°F our hangar is about 5°C or 41°F. Very nice.
Good luck with your project.
Hi Dwayne. I enjoyed this series. Very informative as I am planning to make a couple collectors soon. I also want to clad with aluminum even tho I am much more comfortable with wood. My question is about your long (8'?) metal brake. It looks like it might be homemade. I'd like to make one. Care to share any plans or info on the brake?
Hi, and welcome!
Yes the metal brake is home made. I should have done a video on that, but it was before UA-cam 🙂
I used standard 8’ parts, so, with the clamping bolts and the space they take, I can probably bend 6.5-7’?
I built the bending brake back in 2006. I got the plans from the ch601.org site, within the Homemade Tools section, there is a simple brake designed by Dave Clay. I downloaded his plans, made a few slight modifications to meet my own needs and started assembly.
I just did a quick search on ch601.org, and I don’t see the plans there. I also did a PC search at this end, and of course I think I have changed computers since 2006, and can’t seem to find any notes on my build.
Sorry I couldn’t help further.
Best of luck
Dwayne
Excellent work. The best I've seen. But I have a question about the risk of overheating.
During the summer, when heating is not needed, could the temperature rise too high in the heating unit?
To the point of possibly damaging the foam insulation or the plexiglass?
Thanks!
I have wondered that as well. Having passed through one summer so far, I guess I can say it seems to be ok. Keep in mind that when it is not “running” hot air continues to rise and it is not trapped in the unit, it vents out the top with no fans running.
I had originally put some thought into a venting system, but never got around to it, and don’t plan on it. If I was to do anything different on a future unit, I would try a different material, perhaps metal screen - 3-5 players, painted flat black. I have received some advice from people in Mongolia that have a great deal of success with just using screen. Might be something to try.
Idea, Why not run copper tubing up/down between cans so you can use same setup to heat water in summer? Coarse would have to install shutoff valve w/ airport at incoming water source and shutoff w/drain valve at exit, so you can remove water for winter heater use.
Watched the series with great interest! Do you think I could manufacture a pair of collectors and mount them horizontally? Since the fans are managing the air flow I wonder if the efficiency would remain high? I want to avoid mounting on the roof of the shop yet the neighbouring trees etc would block too much of a vertically mounted unit so I want to put them just under the eaves, tilted up a bit but feed directly through my wall. Your thoughts?
Absolutely yes. Do it. No issue with that plan. On my two units I have one with the hot air coming out of the top and one at the bottom. This whole thing is a great experiment. Maximize sun exposure, and have fun.
This air heater suffers from the same design flaws as all the rest. First of all, the pop cans can be very effectively and solidly connected by cutting the bottom off at the side just above the curve (I used a utility knife blade mounted on a piece of plywood to cut the bottoms off like a pipe cutter does) and using a can opener on the top end. Now the bottom of one can will slip right over the top of the other just like conventional stove pipes. It does make the sections a little shorter so you need a few more cans but the connection or assembly is easy simple and fast. If you look down the center you will see that this system does produce a kind of turbulator at each connection that will help transfer heat to the air while still allowing a fairly unrestricted flow in the center of the pop can tube. The biggest problem with this author's design, is the same as with all the rest, the design has a built in restriction that reduces its efficiency by about 50%. There is no reason to restrict the air flow to just that travelling through the center of the tubes. This only allows the air to collect heat on the inside of the tubes and leaves all the outside heat wasted. The cans can transfer just as much heat on the outside as they do on the inside, so these designs need to allow the air to pass over the inside and the outside of the cans and they will get twice as much heat and any design that requires fans to circulate the air, is useless and a waste of time and money. Convection should pump out plenty of flow and almost instantaneously, as soon as the Sunlight hits it. If the air can pass freely around the cans, the collector only needs an inlet and an outlet to the cabinet and the tubes should be just openly suspended within the cabinet. If you do it this way you will have more heat than you know what to do with. PS: It would also increase flow slightly to make the top of the collector cabinet slope toward the center output port, not just flat across the top and several input ports across the bottom to distribute the incoming air flow.
I'm thinking of pulling air also from behind the cans with spacing between the rows. This would keep hottest air away from the glazing and not conduct heat back out (I'm using glass).
@@davidh9368 Maybe try using 2 to 4 stacked and spaced aluminum screens painted black instead of cans...that would also be suspended from the back of the cabinet.
Dwayne,
Great to see your whole proces!
I was wandering if you put a second fan in your first system and put a restriction in the outlet, so that there is al little more pressure in the cans, what probably make the air touching the cans.
It is worth to try it I think, and easy to fix.
Sending greetings from the Netherlands,
Peter
I think that is a great idea. I might try that. It would be a simple fix without having to dismantle the unit.
@@LifeIsShortDIY Thank you for the excellent video ! This is also the first idea that I had after watching the video. If you put second fan in your first system, you will increase air flow in the first system, and make both systems more balanced, in term of air flow. Maybe the first system can produce more heat, but air flow is not enough to deliver it . Push-pull systems generally have much better flow. Thanks,Vlado
Can you tell me the source and details about the fans you used on your final version? Thanks for posting this series. Very good videos and information. 😁👍
here you go:
SAILFLO Duct Fan Exhaust 5 Inch 110V 16W 141 CFM Large Airflow Exhaust Ventilation Fan for Vents Ducting Attic Kitchen HVAC System Grow Tent Garages Barn Factoris (5"/125mm)
@@LifeIsShortDIY Thanks very much.
If u drill holes that r about half to 3/4 of bottom surface it would act as like a carburetor Venturi and give u turbulence
would you get more effect if you in the midle of the heater put a copper star ish thing and outside of the heater placed a larger magnifying glass that heated up the copper star ?
Should each can column have its own input fan to create air vortex through the tube?
great video but i didnt hear you saying nothing about heat loses in night and as i see you didnt have any close system or doors on fans... so i presume in night the air is going inside the chamber even if the fans are off and you lost heat. second problem i see and you didnt mention is double glass... doubling the glass can have significant improve on heating loss. third point is glass vs plexiglass... if im right glass is better bc dont capture uv light so uv light gain more heat on cans and on the other hand normal glass can capture more infrared light inside the chamber. you do great job and i really like that you show temperature in celsius also.
Thanks for the feedback and comments.
Yes, I’m not worried or even think about heat loss at night. There is no open air to the outside period. It is a closed unit. Very impressed with it.
The glass issue is a separate item. Ideally, I would like to go to glass; time will tell how this Plexiglas holds up. I look at it every few months or so, and have noticed the odd hair-line crack leaving a screw hole. Not worth replacing, but I can see the Plexiglas life might just be 5-8 years. Just a guess. I’ll keep my eyes open for second hand glass. My thinking here is to spend very little money on this heat recovery system.
It is wonderful heading out to the hangar on a cool sunny day and to find it quite comfortable for working. Even when supplementing with forced air furnace, I’m using less propane as the room temperature is already above zero.
Cheers
@@LifeIsShortDIY will you use this for home heating ? if yes why you dont do that yet and if not why ? in my country is heating home pretty expensive these days and every day more and more. next winter could be deadly for as and i have a lot of not used sun on my walls so im going to try it ... first time i hear about this thing just few days ago and worried why ? why is this concept not well known here. is it something in your country that many people know about ? and many of them use that ?
@@radovanbucko4973 In case Dwayne doesn't answer. I'm in the USA. I've never seen one here. I think Dwayne is from Canada? Our northern neighbor. I haven't spent much time in Canada, but never saw one there. I think they are probably very rare there too.
Hi, thanks for the questions.
Yes, my US neighbor is correct, I’m up here in Canada. No I haven’t put any thought into using it on our home. I think my design is really well suited to small sheds and shops, or large shops for that matter.
Also, I don’t see this as a system to replace any heating system, but rather to supplement an existing heating unit. At night, and on cloudy days they are not running. However, on cold sunny days they work marvelously.
If you wanted to use one on a home, that you are living in, I think some time would have to be spend developing some kind of backdraft dampers.
All the best
Cheers
Have you considered mixing the open cans with the cans with 4 holes. Something like 10 open cans then insert a 4 hole can for every 10 open can. Are you following what I'm get at? Or you could do a row of open cans and a row of 4 holes can.
This is a bubble-gum science idea, but I wonder what would happen if the cans were wrapped in crinkled aluminium foil. Rather than the sun's rays hitting a relatively smooth can surface which is mostly pointed back out the glass front, it'd hit an irregular surface with more chance of deflecting the radiation randomly back within the unit, and the surface area between the heated metal and air should also be increased.
Your right, it definitely is an experiment. All of this is. I’m wrapped up in another project right now, but I might make a third heater in the future. One made from four layers of metal screen, just to try that approach. I haven’t’ tried that yet. What is really cool, is snice January I now have had more than 300 hours of free heat coming into the hangar. It can be -10 and windy outside, just awful, and you come inside and it is +4 or so. It really makes a difference.
Lots of positive suggestions from everyone. Thank you.
It's pretty nuts how much energy we can get out of sunlight. You might have already seen it, but this is another pretty cool experiment ua-cam.com/video/eeSyHgO5fmQ/v-deo.html
Hi there I’m from the uk and in the winter months doesn’t get much hours of daylight never mind sunlight! Would this give us some type of heat at all during the cold months? Sorry I’m just learning new saving ideas with the current rise in energy prices!
Hello UK from Canada!
Thanks for your question. First just a quick point - I am not an expert in this field, so I am only providing my opinion with my limited experience in experimenting with the few solar air heaters that I have built.
With respect to your question regarding heat. It is important to remember that solar air heaters do not produce heat, they capture it. A good way to answer your question yourself would be to hold your hand against the exterior of your building. If it is hot to the touch, you could use a solar air heater to capture that heat and bring it inside.
This is exactly what happened to me a few years back. I was opening our hangar door in the wintertime and found the metal almost too hot to touch, yet it was cold in the hangar. “Click” the idea was born, and I built my first solar air heater.
In short, if you don’t have heat from the sun that you can capture, I don’t think a solar air heater is going to help you. Sorry if that is not the answer you were hoping for.
Kindest regards
Dwayne
@@LifeIsShortDIY thank you so much for getting back to me! We have limited sunshine here in Northern Ireland in the winter but the side of my house in question gets the bulk of it all year round and these rooms would be much warmer than the rest of the house I was thinking it would be good for these rooms to benefit from the panel! I’m learning as I go we only have one source of heat and if our power goes out it won’t work! This was something I was hoping would give us a little heat even if it is only a few degrees! Thanks again!
What model temperature controller did you use? None of the adds clearly allow control based on differential temp.
DIGITEN Wireless Thermostat Outlet, Temperature Controlled Outlet Heating & Cooling Remote Control and Plug-in Receiver, Over 300 feet Range, with 6ft NTC Temp Probe (Outlet Detect Temperature)
www.amazon.ca/gp/product/B07YXQ7J8R/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1
Cheers
I need to get someone to make me one. : )
Briliant series, thanks so much for taking the time and trouble to make this and put on UA-cam, Cheers \(^o^)/
Hey, thanks for the feedback. I very much appreciate it. Kindest regards. Dwayne
The heat inside both panels would be equal, with no fans moving air. Consider one fan can only move the air inside the cans, and you are losing excess heat radiating back out through the panel glass. Could two fans reduce the lost excess heat? I've had a manufactured solar heat panel on the roof of my house since 1986 and replaced the 150CF fan 1 time. Love the free heat.
Wow that is fantastic. I learned a lot in this exercise. My third design is the best yet; partial resistance with two fans. I was talking with a fellow from Mongolia and he says to try using downspout with metal screen crumpled up inside. He shared that it provides the best conduction, while minimizing resistance. If I was to build another unit, I think I would try that. Cheers
What kind of metal screen? how would you crumple it up and insert so there is still air flow turbulence but not constrictive airflow?. Have you come across a video you can share?.This idea from research seems to be the best approach.. time, money and efficiencies. We live in ontario canada and currently our only source of heat is wood or space heaters to heat a 1100 sq ft home.
thanks in advance@@LifeIsShortDIY
Hello what if you put mirrors to have extra sun on it?
What type of opener did you use to cut the tops of the cans?
Hi, thanks for the question.
I just used a standard can opener for the top lip, and a “hole” drill for the bottom.
You can see the tops being removed in “DIY Solar Air Heater Part #2” ua-cam.com/video/V9KNzb2wS_0/v-deo.html
and see the bottoms being removed in “DIY Solar Air Heater Part #6” ua-cam.com/video/PhuUWfriKLI/v-deo.html
Cheers
What temperature control are you using?
Great video series.
The math at 5:57 does not work out. 13°F is much too low. Should be showing 43°F.
Fantastic videos, Dwayne. Really enjoying your collection. I see that you have only videoed pop can-based heaters. Have you tried other materials? Round tubes, etc. Here is corrugated steel, which I am wondering if is just as effective but a lot less work? Would love your thoughts on this. ua-cam.com/video/gNldYoeRYF0/v-deo.html