Renewable Energy: Solar Air Heater
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- เผยแพร่เมื่อ 2 ส.ค. 2024
- NMSU Professor Thomas Jenkins shows off a simple solar air heater, which fits into a window space. Natural circulation occurs as the cold room air enters the device and warm air flows back into the room.
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Great video and excellent concept!
The problem with this design is that the intake and outflow are next to each other. You then have recirculation - some of the hot air is sent back through. You could improve with an air intake duct that takes air from near the floor of the room.
First thing I noticed. What kind of moron made this thing? They didn't even seem to do any research on how different designs work, it's the worst proof of concept ever, which is actually pointless, as people have been doing it for decades.
We have been building this design for nearly 50 years. Using black painted corrugated barn roofing as the collector. We connected a box to the out put with an opening at floor level to draw cooler air into the syphion.
We constructed doors for the openings for nights and cloudy days, but found in actual use that they were not necessary. Little if any flow occurred unless the air in the syphion was warmer than the room.
The use of these boxes make a significant increase in the temperature of rooms where they are placed.
During warm seasons they may be removed as no change (other than removing screens) to the window is needed. Or they may be left in place covered.
@@MarcGyverIt
Wrong.
This is the best design I have found for the application intend. I would love to see one that equals or exceeds the benefit.
But IT IS USING the same warm air just reheating it which sounds good to me.
Pay attention just make one of the flows extended inward into the room with small fan blowing air in the heater...
Thanks for demonstrating that it can be that simple.
I like this particular model and may make one, but with some slight differences. I like sealing up all seams and adding a small fan to push the warm air out the top section. I also like using insulated foam on the inside of the box. I have tons of saved videos on different styles, but this one seems the easiest to construct and to fit to my particular windows, stand and all. I plan on using this as a guide for making my first model. I wish the comments focused only on the design and how it works instead of the negative stuff shown here and people trying to convince everyone that they know more about thermodynamics than anyone else. It is a simple, functional design and should be praised for such. Not picked apart for someone else's agenda. Nice job of explaining it and nice video, to boot. An easy diy project to make and use.
He uses sheet metal to separate the layers, not the MDF the rest of the box is made of. The metal of course transfers heat through it far faster, the MDF is like insulation, the metal like a conductor. Probably because the metal absorbs the sun's radiant heat quickly which is good, but then transfers it quickly to the moving air above, but also to the moving (cooler incoming) air below which is not good. The partition should have a 3/4" layer of insulation material under the metal? Maybe just a piece of MDF to make it rigid would be enough insulation? Compressed rock wool will provide R 4/inch, and is organic and won't burn or off gas. Polyiso-based insulation goes up to R 6.6 per inch, but is dangerous if exposed to heat, and off gases over 50 years or so, almost negating it's ecological benefits and diminishing it's R value.
Always when starting a house I think in terms of longevity. No reason why they have to implode right after the last mortgage payment (30 year term). They should last hundreds of years.
Except now of course. Forget hundreds of years, forget 50 years, think 10 years. After that, things will be unpredictable. I think I want to be mobile.
We have been making and installing this design for nearly 50 years. Some have been made with insulating materials others with just plywood. Some have a piece of plywood seperating the chambers some only the corrugated sheet metal. All work. All have black painted corrugated sheet metal as collectors. The transfer of heat to the air in the lower chamber, even without anything else deviding them, has little effect on the heat produced.
The air above is so much hotter than the incoming air the small heat transfer that happens on the bottom of the sheet just doesn't change the total gain.
Most we have made were made of scrounged and/or donated materials so there have been many variations, most are built around the available glass size since other materials can be adapted easier. Often the glass is tempered which makes cutting it nearly impossible. Even if cut and installed it may shatter with just slight change in temperature.
No fan needed. In fact if left on it could push colder air into the room at a time when the syphion wouldn't be moving any.
The syphion only moves air when it is warmer than the room.
With the winter months coming up, this might deserve a try.
Excellent, I love ur work.
A similar device was built 30 years ago and displayed a solar energy show... however, your device is quite better... thanks
Very informative video and concept
Fantastic thanks
This is almost exactly what I have been thinking about doing under my mother's window air conditioner, which is not huge, but too big to remove each winter...there is a nice incline where the window is and I think I can place a nice lean to soda pop can heating panel there.
Yes! That could work.
If you are in northern latitudes, can mount panel flat to wall under the window, if enough room. Or, could make panel horizontal, with a snaking drier duct inside the box. Then, would need to go thru the wall, or if in a rental, boot inlet & outlet tubes thru window, over top or beside the AC unit.
Flat-to-wall helps prevent excessive heat in summer building up inside the box (& making more heat outside, because, it needs covered or vented out in summer).
In winter, sun is lower angle, so is more direct to the panel.
We used 64 sq.ft. of aluminum can stacks & got about $50 reduction in electric heat bill, at about 100’ elevation, about 35 miles from Olympia, WA. There were only about 2 weeks around Christmas & New Years, that we just closed the vent openings in the window boot box.
Ours both recirculated indoor air, & brought in a bit of outside air, & I boosted the airflow with a 4” duct fan , from the farthest side of the serially connected panels.
The fan was at the farthest point from the window boot box, to allow intake air to warm.
Note: any openings to outside, must be finely screened to prevent bugs nesting inside, or birds thinking it’s a birdhouse!
The duct fan ran on A/C, but could as well have run on DC from a solar panel with inverter.
1st cover material was corrugated polycarbonate.greenhouse/patio roof panels.bad. Better was Twinwall polycarbonate panels. Tricky bit, it sealing them well, to prevent heat leaks, or water entering panel. Using recycled glass from patio doors is good! Don’t need to use double layers (nightmare to frame air gap between, & could crack, & algae can grow between the panes)
A smart design!!!
Great idea for some locations. I would use 2-3 layers of thin glass on the front, several inches insulation on the sides, a cold air draw down the wall to the floor, and expand the width outside the window as much as possible. Also consider reflective material on the ground in front of it and on the sides to reflect more sun on it if possible. A hinged door inside the window could shut it off. Done from a 2nd story window to the ground should create a very strong draw naturally in the sun!
Windows and used sliding doors for glass can be found for free on Craigslist and other similar places. Same for insulation scraps, and sometimes wood.
Good ideas. Darwin said it first I believe, about 150 years ago; " not the cleverest, not the strongest, but those who can adapt, survive".
Cold room from cold months... this solar air heater will make that cold room warm in the winter!
no, the thickness of the glass doesn't matter as far as heating. make it thick enough so it wont easily break and you will be fine, typical window glass is fine.
I just came across this video.... I was wondering if the glass thickness mattered at all? Thanks for sharing!
Nice explanation
The angle of inclination is made for summer sun. For winter version it should be much higher... Also i see no heat isolation, at least on sides....
probably did for the off-season. (май, октябрь
The more north, or the colder the climate, the more effect the insulation will have. My first house was a passive solar ski chalet in Quebec. I experimented with colors and heating water when I was a 'Castaway' on a beach in Central America in the '90s. Not surprisingly, my Forest Green bucket heated water to shower temperature every morning, faster than the blue or white buckets. (You couldn't get any other colors)
"So that's why grass is green", I concluded.
Here in Palm Springs where it hits 121F on occasion, we're still at 33 N. Latitude and have two winter months when it's cold (er). These stucco encased houses have a huge 'heat islanding' problem, sometimes the houses don't cool off completely at night, starting a new day with a few degrees "head start" during summer months. I'm going to 'wrap' the outside of the house with polyisocyanurate based insulating panels and a Radiant Barrier reflective surface followed by a light-weight weather cover like steel or thermal wood. (Wood where the sun doesn't hit the wall) The truss roof is another proposition, using a similar but more tedious method to remove all duct-work and seal off the conditioned space below.
Another answer would be a mini-basement-tunnel under the slab with openings on the north side and on the south-facing side. By opening and closing the grade-level inclined access doors you can let either north side air, or pre-heated southside air, into the tunnel space where an efficient but common Air source heat pump can turn that air into AC'ed air or Warm air using one 120 Volt, 20 Amp circuit, powered by a solar PV system.
A million houses in southern California will be energy liabilities as grid power becomes more expensive/exclusive. Moving the stucco concrete jacket that acts like an overcoat on your house during summer, to inside the conditioned space, where it becomes thermal mass and helps to mitigate extreme temperatures, is a good start to saving some of them.
But it's not even in the code yet, and my experience with City Hall so far, is that rules are rules and if your project doesn't follow them, it won't get built. (legally)
The angle is usually determined by location, but in practical use the height of the window and length of material used have a great impact. If a longer box could be made, a sacrifice of optimal inclination resulted in more heat.
If allowed we place mirrors on both sides to increase energy collection. Again the angle of the mirrors are not optimal but they significantly increase heat to the room with little cost.
Brilliant! Still
Fantastic idea ... Unfortunately, I have very few windows having a small stone cottage. How could it be adapted to work & be mounted on a tin roof? I'm not a science wiz but heat rises so maybe it wouldn't get the same flow .. anyone?
I would like to know the btu output of units like this. Is there a conversion vs hours of sun= x amount of btu. Or amount of surface??? Anyone know
Looks like it would work great but how do you control the temperature? Is there some type of a panel to shut the flow of air?
I haven’t seen in any of the many videos with similar ideas how the unit performs at various ambient temperatures. Only one showed temperatures on a cooler day and it seemed that there was a difference in heat produced of hot day - cool day. In other words for every one degree of difference in ambient temperature there was a 1 degree difference in heat production. This would also be decreased in the cooler/coldest months by the lower heat value of the sunlight. This lower value can be felt by walking in the sun in South Florida in the 98 degree summer and walking in the 70 degree fall and the 28 degree winter.
So I would love to see a report that would list something like this:
Date:
Ambient Temperature:
Radiant temperature of box: (sides, glass, ducts,etc)
Intake air temperature:
Output air temperature:
Air temperature in room:
Additional heat added to room: (Humans, HVAC, lights, cooking, etc.)
A good test would be to use a room that has no heat source in it. Let the room cool to ambient temperature. Attach the unit and record the start, and in between times and final temperature when the sun goes down.
Then of course would be the volume of the air moved by the unit. Let’s assume the same temperature of air is produced but the volume moved differs. Obviously a small amount of air will not produce the same heat value of a much larger volume of air.
So, the critical questions are how does ambient air and the time of year affect the heat production? And how would increasing the air flow affect the heat produced?
Will the unit produce hot air when the ambient temperature drops below freezing seems to be the critical question.
OK, these units might be quite valuable in cooler temperatures that are very uncomfortable for us furless creatures such as 40-60 degrees Fahrenheit. But my curiosity is how well they perform in freezing temperatures having encountered 28 degree temperatures in Florida in my uninsulated and unseated camper van. I slept under four blankets wearing three pair of socks, those grey sweat clothes, two pair of jeans, a layer of four shirts, two pair of socks for gloves and a pull down head covering for my eyes and ears and nose. Quite toast until I had to get out of bed... A unit like this if it produces heat in 28 degrees would have been perfect for the day time.
I am a database designer and I will add this question to a table and people can record their results and share them...
Here’s input: I made (2) 4x8’ panels, using mostly recycled materials. Had to be low cost. Might have spent about $200, mostly for insulation, high-temp paint, & a cover material.
Context: Pacific NW, in SW WA, about 35 miles from Olympia, & site was a valley @ about 100’ altitude.
We had these serially booted to a tiny bathroom window (only one usable, facing south), old house retrofitted to modern Codes. So, heat from panels had to wend its way out of there, up hallway, to other rooms.
Winters can (rarely) drop to low single digit, sometimes to the teens, more often, some nights in the 20’s. Summers can & do hit the 100’s, but only usually for about a week.
There are about a couple weeks, around Christmas & New Years, too dim to use solar & get much from it.
The rest of the time, we often have cloudage, which diffuses sunlight, making it omnidirectional, making up for having less of direct sun. So, we can, if need, mount solar flat.
Boxes made of 1x6” boards, lined with 2” R-10 foam boards, then lined those with heavy duty aluminum foil. Then, I processed aluminum drink cans into tall tubes, by punching several more holes in the tops of each, slightly crimping the necks of the cans, and cutting off the bottoms, so they could sleeve together in stacks with baffles inside.
I had tested on 6’ stack for output temp, on a dark, 23*F morning, sight breeze, on our porch. Input temp @ bottom, was 23*F; output temp at top was 23.5*F.
Astonished, I tested it several times, each time getting about half a degree more warmth out of the top. Sold the idea to use this method to heat air!
As many of those tubes as could fit vertically/lengthwise into the box, & used some random sheet metal or foil, to make manifolds at top & bottom, to feed / collect air to/from the tubes. Filled between stacks w/ foam, then painted the foam & cans with high-temp flat back paint.
The boxes were connected by 4” tubes between boxes, upper & lower, to connect at the manifolds. This allowed option to use separately or together, or to add more panels. When the holes were not needed, inserted standardly available caps like pumping or vent parts. The 4” duct fan, fit into one of those holes, & could have been run off a small solar panel..which also would have helped automatically shut the panels down at night, or when light was too dim.
The 1st cover material was low cost polycarbonate greenhouse or patio panels. Those worked marginally, but leaked air to the great outdoors, because it was near-impossible to seal the gaps. And, it buckled a bit from the heat.
But we still got some meaningful heat!
A couple years after installing, we upgraded the cover to Twinwall polycarbonate, better air-leak-sealed. And, installed a 4” duct fan at the far end, to push assist the air to move through.
THOSE improvements brought a significant increase in efficacy! We could see the drop in the electric heat bill, 1st after the install, & more after the improvements.
The design he shows, is going to be less effective, because it fails to separate cold air intake far enough from hot air outlet…. So, the same way some “direct-vent” gas heaters can snuff themselves for same reason, the demo’s box in video is a setup to fail to run as expected.
Our panels, I made a window boot, with a separate, operable vent to output hot air at the top, & an outlet vent at the bottom, with a section of drier vent tubing to bring in room air that was A) below the hot air and, B) separated farther from the hot air outlet. Without that, it cannot work right.
If solar air heater panels need to bring in rest air, do that farthest from the outlet, to allow more time/distance to heat it. Better, use fresh air intake with more panels!
Sorry, lost the output data.
The house was a heating nightmare. Landlords had installed the common Cadet wall heaters mostly on building envelop (espxterior-exposed) walls (read: zero insulation behind them). Those things shocked us with about a $200+ electric heat bill the 1st winter there…& that was using them modestly, keeping indoor temps around 60F.
First improvement: bot a $40 “oil filled radiator”, set only on the 700 watt toggle, then adjusted rheostat as needed. Fiddle fiddle. We sited the heater as close to the middle of that old, 850 sq.ft. house, as possible, to best heat the interior mass, to most effectively retain heat.
But..that dropped the worst winter heat bill by $50. We win!
The solar heat panels dropped the bill, when we improved it, by about another $50. We win!
We used that for about 7 or 8 years, before moving. I am in process of building a similar system into a patio roof we built on south side of a house, similar area. But, with a bit more sq.ft..
The house here, is about 1400 s.f., similar 2x4 construction. Also plan to add solar water preheating for water heater. As at the other place, we keep indoors at around 60*F in winter. Luckily, the back (hidden from public) side faces south, here.
Heat produced from the old panels, of course varies depending on outdoor ambient, indoor ambient, weather, latitude, & user-involvement in regulating it.
It could have been tech-regulated, but that’s more costly & more fail-points.
Our goals were simple:
…beat the rising utility costs in meaningful amounts. We did. And, it could have even been done better.
These days, those who, with engineers, ridicule small efforts as useless, are destructive relics of usurious industry/academic attitudes.
Now, every little bit any can reach to do, helps.
But, there’s a LOT of gonzo tech, people trying to make their own versions, but failing to pay attention to best ways to optimize simple design. Some work better than others, so, they still get something…just not as much as they might.
There are a few core design bits that make it really work…like, the core design bits that make a rocket stove work right (see: Liberator rocket stove).
People just have to really understand what those are, or, the waste time/materials for little good accomplished…or could even do harm (as in rocket stove done wrong)
@@Chimonger1 Remarkable reply! Thanks. May I post on my blog or do you have a url I can point to?
@@jackrodgersjr How may I find your blog? What do you blog about?
(Considering!)
None of these videos show the entire thing from build to installation to the actual room temperature. Why doesn't some one do that?
If a permit is required, you would probably run into something they don't like. During the night for example, how much heat is lost from this device? A simple door(s) inside the house could close off the opening, but that's contrary to true "passive" rules.
I model houses in 3D (Sketchup) which allows you to analyse (fairly new programs for that are either too simple or too complicated, so far) your model to measure heat gain, loss, air flow, effectiveness of thermal mass, changes in glass size and location etc..
You can literally make a wall thicker and then see the changes in measurements of energy movement, or increase the size of a window and see how much more energy is lost during the night. Sun shadows can be shown in minute increments throughout the year.
The point is that an energy device like this air heater would be customized for the house and it's circumstances, like location or floor plan. I can see a few "portable" standard sized units that you might take to a cottage or use on a travel trailer or some other 'temporary' setup. Nothing worse than a frozen outhouse.
Construction is so simple and costs are so low I can't see any need for step by step video. Exact measurement and plans are not possible for every window in which it might be placed.
In addition, the length and depth of the box is not critical.
because you cannot handle the truth
Mother Earth News has been running plans like this since the 1970’s.
I have a question. Everyone is using aluminum. But I'm looking at a table that says copper is twice the heat conductor and steel is 1/7 th the conductor (which then means it holds heat? more). Does this process need the material to be a conductor? if so it is half efficient.
Doesn't this process require steel to absorb the heat to its max then it can do nothing but release it. The enclosure is insulted to contain heat. And shouldn't whatever material used be thicker to absorb as much heat as the surface area will allow before it levels out to cool.(whereas everyone says a thin layer to transfer heat is the way)
Okapi bluetooth is probably the best
system for controlling solar air
heaters
Would love to have 2 for my back windows...Does NMSU sell them for fund raising by chance? Would love to purchase.
EVER CONCIDERED DOING A REAL WORLD TEST IN COLD WEATHER
@tommy aronson These do in fact work well in cold weather. There are many videos online that demonstrate this.
Wouldn’t the hot air get sucked into the cold vent?
As cold is dense
U GOT SOMETHING FOR THE ROOF TO THE WINDOW
Wat about actual winter time temperatures...........???????
Brilliant! Where can we purchase this??
Build it instead of buy it he breaks it down quite well. just take your measurements on a few windows yourself and pay attention to detail. You will save money on the unit as well as the heating.
GreaseWorX Studio
David La
Yea man what did you need?
So a a can youst paint my window in black and i have same product as yours, tnx
this a room unit ? any smaller
Someone needs to re-think the effects of solar on that building in the background. Look at the aluminum foil radiant barrier set-up to keep the sun out of the window.
Sometimes heat gain is desirable, sometimes not.
What happens if it's covered with snow....?
Just add micro glass on top to double the suns heat on the metal....
what if snow covers the unit?
it means - winter has come
it means that snow has, in fact: covered the unit.
So your saying that size does matter,.......... I knew it ! Lol
This make on a solar heat is not efficient at all. Look on you tube for other models.
Probably the worst I've ever seen, right here.
see solar can heater
Good idea,
more simple, maybe 1 fan 12V.
Dream would be plastic bags to buy, cheapest.
You could add several if needed.
I blame squirrels
This man is a professor but it never occurred to him to paint the entire unit black where the sides of the thing could warm up and reduce heat loss if not add some extra thermal energy? Would see obvious to me to make the entire thing black where it could be impacted by the sun. looks like the collector area could be as much as doubled even if not active all at once.
You only want inside black, & insulate the inside of the box, except where glass is. And, mount it at angle perpendicular to winter sun, not summer sun. Or, mount flat to wall, to ease mounting, & ease shading the panel in winter.
These panels need shaded in summer, & vented to outside during summer, to block heat entering house in summer…another point towards mounting flat to wall, in latitudes like the Pacific NW.
That cold intake is still to high up. Cold air &hot air next to each other wont work dude sorry. Cold air inside the room exits at floor level & Hot Air pumped in Mid-Way.
I don’t think he has studied various designs of solar air heaters; his design has a couple flaws in design that, unless compensated for, will cause poor performance.
Its not a device as it has no moving parts. Its a heat exchanger.