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Almost Free Solar Hot Air Collector

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Picture of Almost Free Solar Hot Air Collector
I hate throwing anything out untill I have exhausted my mind, searched the web or visited Instructables for other potential uses. I have not found and hot air collectors made from light fixtures so here you go.

Electric Car Conversion;

http://goeving.blogspot.com/

YouTube Solar Hot Air Collectors;

http://www.youtube.com/user/EcoGreenGroup

Making a solar hot air collector out of free used 2 x 4 metal light fixtures, free old glass and free black paint to reduce our carbon body tape outline, reduce our untility bills and save money.

We are building and installing 14 of these hot air collectors on our south wall of our 140 year old house in Ontario, Canada. During sunny days in the winter these will completely heat our house for about 6 hours. After we make these, we will join them together venting the cold air from the bottom of the rooms and exhaust the top vents to the top of rooms. The fans will help increase the air flow to these rooms. The next collectors that we make will also be insulated and have a metal baffle inside to help concentrate the heat. The collectors then will be connected to the house and flexable dryer
duct inside the house will vent heat to various rooms . Check out our You tube home page for more info.

         Free Heat.
         No Fuel Needed.
         Renewable.
         Cost effective.
         Green.
         Recycled.
 
 
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Step 1: Dumpster Diving Time

Picture of Dumpster Diving Time
 
Materials needed
         Old light fixture (Restore).
         Aluminum Tape.
         Flat black paint (Restore).
         Glass cut to fixture size.
         Silicone caulking and gun.
         Latex or nitrile gloves.
         Protective gloves for handling glass and cutting metal.
         Hammer and Screwdriver.
         Metal scissors.
         Thermometer.
         Drywall screws and drill with a Phillips bit.
         Glass cutter and marker (If cutting own glass).   
 
You could possibly use a peltier element for powering the fan.
shaggydoo1217 months ago
I really like this and will implement it to offset my heating bill during winter ! Brilliant idea !!!
The overall concept is great. I am using a 3" - 12 volt bilge fan and a 12 volt thermostat that is set for hi low temps. All of my power is from 2-10 watt solar panels and small gel battery. My solar controller/charger is from Harbor Freight. My heat tubes are 2 ft. pieces of aluminum duct and elbows. My glass is a used 32 x 60 inch aluminum window. If you mount the fan on the return air side, you do not have to worry about the high temps. If you have an existing central air unit you can hook this straight to the plenum and your inside thermostat will react to the supplemental hot air you are pumping into the house. These are not free, but cheap enough! I am about finished with this one. I will post pics and instructions as soon as I finish my installation.
kd1s7 months ago
One mod I could suggest to this is a liquid circulator. Just attach some 1/4" or so copper tubing and paint it black too. That way you get the double benefit. Just pump the liquid into the house and to a radiator and a fan and presto-heato!
Excellent advice on being an Eco recycler. Another place to ask is where you see a commercial building tenant improvement in progress. They often gut the interior including 10 year old obsolete lighting for the panel boxes and acoustic ceiling tiles that could be used inside the boxes for insulation.
ecosteve (author)  Woodenbikes1 year ago
Thank you for your comments, When you think about it even poop is not waste, methane gas (cooking heating), fertilizer and even a source of solid fuel, Even in some places in the world they polish the floors with it. One mans trash can also change the world for the good.By the way here is an updated you tube video about solar hot air collector that I made. Enjoy

http://www.youtube.com/watch?v=NZwdhjTWU0c

Eco Steve
trevman1 year ago
I've heard that putting foil behind radiators reflects heat back into the house (rather than heating the walls). Has anyone considered lining the box with tin foil rather than using black paint?
ecosteve (author)  trevman1 year ago
Thank you for the comment, although in this instructable I did not line the box with foil instead just painted black. But in this follow up You Tube video tutorial I did seal, install foil backed foam board and paint the surface flat black to absorb the sun. Enjoy

http://www.youtube.com/watch?v=NZwdhjTWU0c

Eco Steve
twighahn1 year ago
i have seen these but this is easier than the others
wOw   impressive     its shirley got me thinking.    
would like to see photos of the finished installation ?  could boxes like these be constructed out of wood or is there an inherent advantage to metal ?
I WOULD LOVE TO SEE PHOTOS AS WELL? PLEASE!
http://www.instructables.com/id/Solar-Heater/

From some of the discussion on that 'ible, it sounds as if *not* using metal may have some advantages.

So even though metal construction might be slighly less efficient, the fact that ecosteve got these fixtures for free and is keeping them out of the landfill probably equals everything out in the end.
ecosteve (author)  Sabata3 years ago
Thank you for looking and  I have 14 to make so i will try many of the ideas mentioned as feedback including insulating the rear inside and sides of the up coming collectors. Eco Steve
I would love to try some of these out.  I agree with some advantage to using non-wood, but like was said I agree that saving from the landfill has more advantages.  Not to mention if you cold save some sheets or pieces of styrofoam to glue to the back of the metal it would help with retention of heat.

Great idea! 
inherent advantage to metal ? not really but these were saved from the landfill
ecosteve (author)  lordzion3 years ago
Thank you for looking and  I have 14 to make so i will try many of the ideas mentioned as feedback including insulating the rear inside and sides of the up coming collectors. Eco Steve
ecosteve (author)  lostinthecolonies3 years ago
Thank you for your comments. Eco Steve
HOW ABOUT USING TWO LAYER ROOFING:
TOP LAYER CLEAR ROOFING AND BOTTOM USING FLAT BLACK PAINT TO ATTRACT HEAT. USING TWO BY SIX’S BETWEEN LAYERS ALLOWING FOR ROOM FOR AIR FLOW, FANS AND DUCT TUBING CAN BE DRYER VENTS TO TRANSFER HEAT INTO HOME.
ADD FANS ONLY TO LOWER PORTION OF ROOF TO ALLOW EXCHANGE OR IF REPAIR NEEDS TO BE DONE TO FANS.
I WOULD USE SEALANT SUCH AS SILICONE TO PREVENT LEAKS OF WARM AIR
I’M WONDERING IF DOING THE ENTIRE ROOF THIS WAY WOULD WORK IF YOU HAVE NO TREES ABOVE YOUR HOUSE AND YOU WOULD GET HEAT FROM SUN FROM DAWN TIL DUSK.
MY OTHER THOUGHT WAS ADDING BLACK PIPE IN S SHAPE THROUGH OUT THE SAME ROOF FOR HEATED WATER.
THIS ENTIRE APPLICATION COULD BE PLACED ON THE GROUND SIMILAR TO INSTALLING SOLAR PANELS USING A 50 DEGREE ANGLE IF SNOW IS AN ISSUE.
WHAT MIGHT LOOK COOL IS HAVING OFF ROOF DESIGN OF SOLAR PANEL THEN HEATING AND WATER THEN SOLAR AGAIN ALL OFF GROUND. i REALIZE USING TWO LAYER OF ROOFING MIGHT ME COSTLY AT FIRST, BUT THINKING LONG TIME INVESTMENT OF HEAT WOULD BE BENEFICIAL.
I SURELY CAN’T WAIT TIL YOU TRY THIS AND PLEASE COME BACK AND LET US KNOW HOW IT WORKS OUT FOR YOU. INCREDIBLE IDEA TO USE OLD LIGHT FIXTURES! I ALSO LOVE THE IDEA OF PANTYHOSE ESPECIALLY IF IT’S PLACED CONVENIENTLY WHERE YOU CAN CLEAN IT OR REPLACE IT! ANOTHER IDEA MIGHT BE TO PLACE THE FAN JUST INSIDE THE AIR VENT.
jbrown702 years ago
Should have drilled a hole n cut a cleaner hole with a jig saw on the back open side. Plan on building one myself, thx for the info.
legusamos2 years ago
Hahahahahahaha! I'm cracking up!
nbowles2 years ago
In a UK TV show called "it isn't easy being green" they did something similar, they pumped air from a greenhouse into a chamber below the floor where they had dumped tons of mass - what they used was crushed glass but maybe gravel or something like that would work as well. The mass absorbed and then re-radiated the heat slowly, at night so the plants were warm all the time extending the growing time into autumn and making spring earlier. I guess you could do this in a house or bring water through the panel and then route it into underfloor heating system, regardless of whether a boiler or heat pump is also attached. If you were to do this then radiators painted black may work better?
JRPCS2 years ago
Would using corrugated metal (like roofing) painted black with holes drilled into it to form a matrix of holes be efficient as a thermal collector in an insulated glass fronted collector?
Having a connection to the house thermostat and a "normally open" warm air fan switch (closes at 70 degrees) in the collector for the fan would make the most sense to prevent cold air entry...before the system has heated ...and prevent room/house overheating. Both would need to be "on" to have the fan operate.
Also, it seems that having the ability to close the system off via insulated room vent covers would make sense for summer.
Isn't insulation needed for the entire collector (except the glass front)?
Thanks
JRP
johnny3h3 years ago

This is a good instructable, but I would like to make a few suggestions.
1.  Unless the fan is specifically designed to survive the potentially high temperatures that could occur on some days, I suggest that the fan be mounted at the lower end [IF that's the cooler end] of the collector.  Even it the fan is rated for the maximum obtained collector temperature, it will last longer if it is in the cool, inlet airstream.
2.  Unless I missread your presentation, your system takes/uses outside air, heats it and injects it into the house [I have to assume this as I did not see a discussion regarding ducting]. This "one time" use of cold outside air is very inefficient, and can be eleminated by installing INSULATED ducts for the hot air to the house, AND a "return" air duct from the house to the air intake of the collector.
This can be accomplished by opening a couple of non-adjacent lower windows a few inches [just slightly more than the diameter of the insulated duct, and installing a filler "plate" [plywood, plastic, or metal] and close the window on it, and caulk.  Before installing the filler plate, drill a hole to fit the ducts. 
To reduce premature recirculation of collector heated air, the hot air inlet and return air ducts should be as far apart as possible, but at least 8 or 10 feet.  Also to improve effieiency, the return air duct should be extended inside the house to the floorline, and the warm air duct directed horizontally from the window filler plate out into the room where in rising, the warm air will better mix with the indoor air.
To reduce buildup of dust and lint in the collector, some kind of filter screen should be be applied to the floor level return air duct.  This filter could be scrounged out of an old scrap clothes dryer, or enve a piece of pantyhose or woman's stocking.

Again, I commend you for a good idea and well organized presentation.

Regard to all, Johnny3h

 

ecosteve (author)  johnny3h3 years ago
Thank you for the nice comments, I just can't let anything go to waste. Here is a link to our 1984 Pontaic Fiero converted from gas to electric using used forklift parts. http://goeving.blogspot.com/
sds.jpg
 Well maybe you didn't read the instructable completely, but the fan is meant to blow the hot air into the room, so if he put the fan where the cool air comes in, he would just be blowing the cold air back into his house.

As for putting the inlet/outlet 8-10 feet away from eachother, he can no longer use the discarded fixtures he has found, and he also states the upper and lower holes will be ducted to the house, meaning it will take cold air form the house, heat it and return the air to the house.

It bothers me how many people offer "suggestions" and don't even read the instructable. PLEASE take your suggestions and make sure they actually are suggestions, not just reiterations. 

By the way, an air filter IS a really good suggestion. 
Having a fan at either end won't alter the temperature of the air flowing to/from either end in a system like this one, the only difference will be that the fan will not be subjected to the hot exhaust temperature and will instead be kept at the cooler intake temperature, which will increase the lifespan of the fan's motor considerably.
 Well if the fan is then sucking cool air into the unit, instead of blowing hot air out, cool air will come in too quickly, not having time to heat up, or cooling down the air that is heating up. 

And if you have one an sucking cold air and one fan blowing hot air, it just won't allow enough time to heat up, its just circulating too quickly.

It's obvious to me, anyways...
Re: your first paragraph.

I think you misunderstood what Nimphious was trying to say. I don't believe he was suggesting a fan at both ends, but pointing out that a you can put one at either the top or the bottom and it won't affect airflow volume, only fan temperature.

Assuming equal duct size on the inlet and outlet, the volume of air moving into/through/out of the unit will be equal (or pretty close to it) regardless of fan placement. So by placing the fan at the cold air return, you'll likely prolong its life because it will be in the cool(er) airstream rather than sitting at the top where the temp can get quite high.

That's my take on in, FWIW.
Well when you make one and try it out, you will find that forcing cool air into the box will decrease the temperature of the air in the box, and it won't be heated (as much). I was experimenting with several ways of off-grid living in my attempt to build a low cost earth ship, and I can tell you, it doesn't work if you're blowing cool air into the box.

And, johnny3h making your points bold doesn't make them any more legitimate. And learn to be concise, I didn't even read the first reply to my post you made, because it was longer than your original comment, and you since you commented 15 minutes apart, you could have made it into one post instead of replying to both my comments seperately.
From my understanding, fans have a given cfm (cubic feet per minute) rating. That said, it seems that whether you put the same fan at the inlet or the outlet of this heater, it will still move the cold air through the inlet to the heater at the same amount of air volume and speed either way. So either location would provide the same results. Now, there could be an issue of whether or not using a fan at all would help the output of heat or not. If the air moves through too quickly you could keep the whole thing from really absorbing much heat. Heated air rises on it's own and pushing (or pulling :)) it through at a faster rate may not actually be a benefit. If one would be used it definitely should be a small one.
By the way, I really appreciate this instructable. I have wanted to come up with an easy and cheap solution for integrating passive solar heating into garage door panels that I could still open and close normally and this could be the best way. The taper of the fixture boxes along the 4 foot sides make them perfect for this use. Of course, I would install them horizontally on each section and probably use that flexible foil insulating blanket to connect the rows together as far as heat transfer goes so the heat would travel in from the bottom, through all the rows, and out the top to heat my garage FOR FREE!! And I could still use my normal garage door as intended, easily opening and closing it at any time without assembling or dismantling any other device I created to do the same thing. I can't believe I never thought of using them before.

1.  The temperature inside the "box" is not the issue; The important point is the total amount of  heat, and the temperature is not a factor in the number of Btus ["amount"] created by absorption of sunlight which is converted to heat.
Yes, the temperature will be less, but the amount of heat transferred will be substantially the same.
2. It also does not matter whether you force the cooler air into the box, OR suck it in via the fan being at the discharge end.  The rate of air flow, and the volume of airflow, AND thus the amount of heat transferred from the radiating portions of the box will be essentially the same, and thus whether the cooler air is blown into and through the box, or sucked in and through the box is immaterial.
3.  I'm not sure, but I'm begining to suspect that you may think I'm suggesting taking cold, outdoor ambient air into the box, and if that's the case, then yes, it would cool the box more than if cool, but I'm suggesting that the warmer, recirculated indoor air be circulated. 
I've never advocated taking outdoor air into the system.  The cool air you talk about is the same cool air from inside the house, whether it's being being blown into the collector/exchanger box, or sucked out of it with the fan at the outlet.
4.  The purpose of the bold type, unlike as you allege, is not any attempt increase the legitimacy of the statement, BUT INSTEAD to emphasize a point as I''m doing right here!
5.  Length and/or timing [15 minutes apart] of any of my comments have nothing to do with combining into one post.  My first comment was done at its time in response to my observation of your first post [11:08am], and my subsequent post was in response to its trigger [Your SECOND post at 12:45pm, about and hour and 4/3s later than your first, and even after my post.  How could I have included my second post comment to your second post BEFORE I saw your second comment?

At the time I read your first post and responded to it I was not even aware that you had made a second post.  So, don't hold that against me for not answering both in the same post.

Now, this has gone on far longer than enough.  You are a TROLL, and posing issues/problems that don't exist, just for the sake of stirring up trouble.

I have worked very hard to comply with the site "be nice" policy but it's obvious you are trolling and that is NOT NICE!!!!!

Again, I just read the end of that, because it is WAY too much to read. But no, I am not a troll, I was defending the author, because 2 out of 3 points that you were "suggesting" had actually already been stated by the author. And you are saying that they hadn't explained enough for you to understand, and they had. 

So again, please read the instructable completely before "suggesting" something. Reread it if you need to. I see it ALL the time, and no, not specifically from you, but in this instance, yes. 

I'm not going to waste any more of my time on explaining this to you, I do have much better things to do, and I have half an LED chandelier sitting on my workbench right now waiting to be completed.

Cheers
I think there's a little communication problem here and I can see both sides of the argument. I'd like to point out that pure physics and mathematics don't always work in the real world as no system is ever a perfect 'closed' system. I would also like to suggest that if the airflow was increased then faster moving air would result in lower air pressure on the radiant surfaces which may well decrease the amount of heat being transferred. But I could be wrong. As I say, I can see both sides. Be good people.
Quite right. I believe some of the confusion could be eliminated if the work that a fan or blower does is reviewed in a more scientific yet simplistic view.

Do not think of a fan as sucking or blowing. The fan is doing only one thing, moving air through a space. The work that a fan does has only one measure, CFM. No matter what a fan's capability is, it's cfm can only change because of rotational speed and/or obstruction of it's inlet or outlet side.

if the duct, (in this case the solar furnace) remains static, and only the location of the fan in the circuit changes, the cfm AND the velocity will not change.


The ONLY way I can figure a measurable difference could be obtained in an extreme temperature situation is that hot air is less dense than cool air. In that extreme case a fan would push more cold air than warm, but only by the difference in density.
So much for the "be nice" policy. :-\

On a lighter note, this reminds of a buddy who used to refuse to run the blower in his car on high during the winter because he believed that doing so would actually "cool the air down," the same as you cool off your food by blowing on it.  We never could make him understand what was really going on.
1.  IF The fan sucks cooler air from the house, it forces the cooler air into the collector box(s), automatically forcing warm air from inside the box OUT through the duct into the house, 
So, it makes no difference where, within the same "plumbing" system layout, the fan is located.  It could even be INSIDE the house at the opening of the "return" air duct!
I did not suggest installing a second fan in the intake/return air section, only moving the fan from the warm air discharge end of the box to the cooler return air inlet.
Even IF two fans were used, the amount [Btus]of heat created by the black interior of the box would NOT change the amount [Btus] transferred into the house. 
Yes, the air would not be as hot [temperature-wise, BUT the amount of heat [Btus] will be the same.
As a matter of fact, this MAY be a good thing as it keeps the system operating temperature DOWN, and thus since lost heat transfer is directly proportional to the difference [Delta T] in temperature between the air inside the collector and the air outside against the glass glazing, then there would be less heat lose, and thus INCREASED EFFICIENCY!!!!!
Thanks for your understanding of what I was saying, and the new points you  made.  I had no idea that someone would misunderstand the suggestions I made.  And I fully agree with your assessment of the issue.
micobanff:
1.  From the standpoint of flow rate ,OR temperature of the incoming or outgoing air it does not matter whether the fan is at the intake or exhaust end of the closed box of the collector as the flow rate AND volume will be the same. 
Instead of "sucking" hot air from the collector and "blowing" it into the house, I'm only suggesting that the fan be located in the same circulating "system" at a different point and thus "sucks" cooler air from the house and pushes it into [and thus through] the collector box, and then by duct into the house.  Changing the physical location of the fan does not change the system's operation.  This suggestion is NOT a reiteration of, but an addition to, the instructable.
My suggestion for the fan being AT the cooler air intake end of the solar heat collector box is so that the fan motor and bearings will not be subjected to the heated air, which should allow for the fan to have a little longer lifespan.
It will still blow hot air into the room IF it's sucking air from the room , blowing it into the collector box, which will then force the heated air from the box and through a duct INTO the house!  Thsi suggestion is NOT a reiteration of, but an addition to, the instructable.

Regardless of where the fan is located IF the discharge [hot end] of the collector is ducted INTO the house, then the fan won't be blowing "cold air back into his house."  As a matter of fact, there really is no hot or cold end of the collector box(s) as air passing through in either direction is heated just the same!  What determines whether warmer or cooler air is determined by the location of the suction[return[ air and discharge air duct's location inside the house.

2.  Sure he can continue to use the battery [or "gang"] of collector boxes he's already "found" and built, by adding just a few more feet of duct between the boxes and the house air extraction point and heated air injection point.  And as I suggested before, for efficiency [to prevent heat loss] I still recommend insulating all ducts [return air, or heated air].

3.  You write, "It bothers me how many people offer "suggestions" and don't even read the instructable.  PLEASE take your suggestions and make sure they actually are suggestions, not just reiterations."

This last comment of yours more than "bothers me" as it's obvious you did not understand my comments, and jumped on me before doing so.

I DID read the instructable, and my suggestions ARE NOT reiterations, but new and different applications of the instructables iterations.
ecosteve (author)  johnny3h3 years ago
Thank you for looking. Eco Steve
Re#2:

Really?

"After we make these, we will join them together venting the cold air from the bottom of the rooms"
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