solar thermal heating

   / solar thermal heating #1  

forgeblast

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Location
nicholson, pa
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John Deer 318
I am looking to suplement my heat, by making a solar air heater.
I have found plans that use, aluminum cans and gutters. Then a fan is hooked up to pull the air out when it is warm enough. I figure this would run all day long when we are at work, heating the house nicely.

Two Solar Air Heating Collectors Using Gutter Downspout Absorbers

My plan is on my south/southwest facing wall to build 2, 4x6 collectors that will be indepenent of each other. I can also make one 4x8-9 foot tall, but i want to see how these two work before i get into a third .

I am wondering, if anyone has made these before. Also would i be better off putting in

FinTubeBaseboard_3_4_Element_Only.html

the fin tubes from a baseboard. would they give me a better surface/heat ratio.
Also anyone know where to buy some cheap ones?

Has anyone used the "PALROOF" vs lexon as the front. I know there are studies showing an arched window is better on these, i wonder if the many arches of palroof,sunroof etc that the box stores carry would be better. I worry that how thin they are would allow heat to escape.

Once again, im just in the planning stages, will probably make it this summer, or once i save up enough money. The downspouts are a fast cheap alternative, the fins may cost more but may produce more heat.
 
   / solar thermal heating #2  
On the finned copper tubing its design is to convect heat away from the water core. Solar heat absorbs radiant heat so the finned tubing has the fins on in the wrong way for solar. Your state is Pa and like Ontario I am not sure if we get enough sun. At the plant our 45KW PV field is covered in snow.
Craig clayton
 
   / solar thermal heating #3  
On the finned copper tubing its design is to convect heat away from the water core. Solar heat absorbs radiant heat so the finned tubing has the fins on in the wrong way for solar. Your state is Pa and like Ontario I am not sure if we get enough sun. At the plant our 45KW PV field is covered in snow.
Craig clayton
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In 1973 I built a test panel to check static temperatures. A 1 foot square wood box with a black aluminum plate and on it aluminum cans painted flat black. The difference in temps. on similar ambient days in February was about 40 degrees on two different reflective surfaces. 180 degrees sitting on dormant light brown grass and 230 with snow cover on the grass. The outdoor ambient temp. was around 28 F. Further experiments showed an increase of 12 degrees when two small pieces of white styrofoam were placed horizontal in front of the panel.
 
   / solar thermal heating
  • Thread Starter
#4  
They would be mounted on the side of my house on our deck, and the roof overhang will not cast a shadow on them. I have read about a lot of them used in the north, and they raise the temps great. Your right keeping the snow off them will be a must to get them to work.
They would be boxes sealed with silicon, and lined with insulation all painted black. If the fins were painted black would they work better?
If the fins were placed in the rain gutters would that imped the airflow too much or would that allow me more surface area to store heat.
 
   / solar thermal heating
  • Thread Starter
#7  
that mother earth news article is what planted the bug. Looking at deregulation of our electric company this year is another reason.
I just want to do it right.
 
   / solar thermal heating #8  
I am looking to suplement my heat, by making a solar air heater.
I have found plans that use, aluminum cans and gutters. Then a fan is hooked up to pull the air out when it is warm enough. I figure this would run all day long when we are at work, heating the house nicely.

Two Solar Air Heating Collectors Using Gutter Downspout Absorbers

My plan is on my south/southwest facing wall to build 2, 4x6 collectors that will be indepenent of each other. I can also make one 4x8-9 foot tall, but i want to see how these two work before i get into a third .

I am wondering, if anyone has made these before. Also would i be better off putting in

FinTubeBaseboard_3_4_Element_Only.html

the fin tubes from a baseboard. would they give me a better surface/heat ratio.
Also anyone know where to buy some cheap ones?

Has anyone used the "PALROOF" vs lexon as the front. I know there are studies showing an arched window is better on these, i wonder if the many arches of palroof,sunroof etc that the box stores carry would be better. I worry that how thin they are would allow heat to escape.

Once again, im just in the planning stages, will probably make it this summer, or once i save up enough money. The downspouts are a fast cheap alternative, the fins may cost more but may produce more heat.

Hi,
Solar air heating collectors work well -- I use one to heat my shop.

Mine is the $350 one referenced above. I've had it for 5 years, and it performs well. Since its a thermosyphon, it does not require any fans, controllers or electricity. It has had zero maintenance in 5 years :)

If you want to learn more about solar air heating collectors, some sources of info:
- the link you give is for Scott's gutter down spout collectors -- he started and runs the Yahoo discussion group "Simply Solar" -- there are lots of solar air heating collector people there -- good place to ask questions.

- Scott and I are just in the middle of testing several different air heating collector designs to determine relative efficiency. My results to date here:
Solar Air Collector Performance Testing


Scott's initial results show the collector with the two layers of screen for the absorber to be doing quite well. This is cheaper and easier to build than the pop can collectors or the downspout collectors.
The $350 collector is also a screen absorber.

I plan to test the screen absorber collector with fan forced air next, but its going to likely be a couple weeks.

On glazing, a lot of people use SunTuf corrugated polycarbonate glazing. Its tough, has good transparency, and holds up well -- the 5 year old SunTuf on my collector still looks like the day it went up. For cold climates, another good choice is twinwall polycarbonate.
Solar Collector Glazing Materials

I don't believe that the dome shape that some people use on their glazing improves thermal performance, but it is a good way to give plastic glazing more stiffness and to keep it from buckling as it warms up.

One thing to keep in mind is that size does make a difference in solar collectors. The full wall air heating collector that in the $350 link above does a good job of heating my 600 sqft shop on sunny or part sunny days. Its about 160 sqft of collector and the shop is fairly well insulated. I do live in MT, so tends to be cold. What I am saying is that the two 4 by 6 plus one 4 by 8 is just getting up into a size that is useful. If you have room for more, I'd consider putting more in.

Gary
 
   / solar thermal heating #9  
Hi,
Solar air heating collectors work well -- I use one to heat my shop.

Thanks for the info. Do you cover them in the summer or just block the air ports? Do they lead to more cooling off in the shop at night?
 
   / solar thermal heating
  • Thread Starter
#10  
Thank you very much, I know I will have more questions for you.

Gary when you say screen, is that the sofit, you have two layers of that?
 
 
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