Feedback on my solar idea/thinking

[GeeMac]

that was the story of stacked and painted cans on a steel plate. The cans had both ends removed, stacked and soldered together. Several columns of the cans were attached to the steel backing.  The whole thing was painted mat black to absorb as much solar energy as possible. It has no moving parts. The cans and backing heat in the sun. The heated air in the cans rises, sucking in cooler air at the bottom.

Because I am somewhat of a neophite, I am asking if I erected a few versions of this 'inside' my house while the temp outside is about -30 and placed them in the sun that is coming through the window would they help to heat my place or is this a form of perpetual motion that will not work?

[MattM]

Your sun coming in the window is not going to magically improve because you put a dark collector in front.  You'd collect heat not normally coming in the room to improve your heating.  Using the existing energy already in your room is zero improvement.

[Clifford]

There are things that you can do around a window...

Heat Absorption...  

Consider dark materials around the window where the sun will strike.  Blacks, browns, etc.

Heat Sink...

A dark brick inside the house will absorb and store the energy from the sunlight, and enough of it will help even out the temperatures in the house.

A dark tile floor might be good too.

Note, unless the temperature of the brick/tile gets to be above 80 or 90 degrees, it will absorb heat from your hands/feet, and will feel cool to the touch.

Your tubes might, in fact, be counter productive.  You want heat to be low down.  Your tubes might direct it towards the ceiling.

If you mount your solar panel outside of the house...  and make it sufficiently large, then you suck heat in when it is warm at the top of your pipes, and leave it closed off when it is cool, or you don't want the heat.

[Bruce S]

DUDE!

   He's asking for improvement of his idea(s) not Criticism.

Help by explaining why, not just thinking he needs a rude come back.

He didn't ask for magic to happen

Besides, by using the dark containers at the window does help by focusing the sunlight coming into a device that can then be used to help even if just a little to warm that room.

So your comment was not necessary and is wrong, try again only be nicer, there's enough rude people already

Bruce S

[Bruce S]

Clifford;

  Very good , I would like to add that over at builditsolar there's some good write ups to help as well. I like the pics :-)

Cheers;

Bruce S

[GeeMac]

Thank you all. As long as it isn't some sort of weird unity device it might be worth making one to test the idea. I'll report back with the results when I am done.  

Keep having fun.

[mixerman]

I have been collecting parts to do this to. It will be outside to house and piped in to the interior room.

While cleaning up the house I was going to pitch afew 8' light fixtures, then I though this might be a easy duct part for inside the solar box. Holes will have to be made for the cans, then fasten in.

[MattM]

I had no intention to be rude.  I was just pointing out the fact that this plan is not a benefit inside the house.  You can find a lot of online blogs by people that have experimented with these ideas.  The basic trouble is the night time.

With electrical solar panels you can put a diode into the system to keep the energy in the battery when the night comes; the diode prevents bleed back of electricity to the solar panels.  The system the OP suggests should work by basically moving heat the interior of the house to the interior of the house for no gain.

I think he more of less wants a solar heat collector; he wants to move heat from the solar heat collector to the interior of the house.  In the most effective solar heat collector systems they use a liquid to transfer the heat from cold to hot ends.  In daylight the collector box is the hot end and the interior of the house is the cold end.  With these solar heat collectors you tend to lose too much energy at night because there is no simple "disconnect" in the system to prevent the heat from going to the colder collector box at night.  Its a real pain to drain out the system every night in order to block the transfer.  But that is the basic problem with these devices.

[MattM]

Sorry for multiple posts.  I had a type: the heat transfer is from hot to cold ends.

[zeusmorg]

 Passive solar collectors can be very efficient, however putting one inside a window will not give you an appreciable solar gain, unless you normally reflect that sunlight back out the window.

 Building a solar collector and placing it under a south facing window, however can gain you added heat in a room. Designed, insulated and angled right for the maximum performance.

[spinningmagnets]

GeeMac, it will work. Its been done. Paint one can white and one can black, set them a foot apart in the sunlight just inside a window, check with your hand in 30 minutes.

The concrete runways on Midway Island were colored black so they would be hotter at lunchtime. That way there were no birds on the much hotter runway when planes would land about 2:00. This dramatically reduced expensive bird damage to planes.

Most people don't want to block a window view, so the common method is to make a glass-covered box with the vertical stacks of dark aluminum cans inside. An insulated clothes dryer exhaust flex-tube can pull cold air from the floor up through a window, then down where it enters the bottom of the collector. The hot rising air can be ducted from the top of the collector back into the window.

One guy just permanently mounted it on the outside of a south wall, with two holes in the wall. One hole low, one high.

Setting a temporary collector inside a window will work too. The thermosiphon flow (hot air rising without a pump) directs and increases the airflow past the window. Without a flowing collector, the air in the rooms sunlight will warm some, and the air at the far end of the room will stay cool.

Inside these links there are even more similar links, read them all.

http://www.fieldlines.com/story/2008/4/3/23655/59321

Solar hot air collector, aluminum soda cans

http://www.fieldlines.com/story/2008/7/9/02425/95131

Solar hot air collector, garage door

[paulb662000]

As some of the other comments have stated, many people don't want to block a window either for view or provided light. Mother Earth News has a design for a solar heater that hangs outside off a window sill and circulates air passively without blocking the window. Maybe the design in the link will work for you.

http://www.motherearthnews.com/Renewable-Energy/2006-02-01/Do-It-Yourself-Solar-Heat-Collectors.aspx

Paul

[PHinker]

   There's a youtube video about a fellow who is building these commercially.  If you google on 'cansolar' I think several references will come up.  As others have stated, I'm not sure having the absorber on the inside of a window would be the best solar gain (probably better than just the window however).  Since you're already getting solar gain from the window, the black absorber will only be an incremental improvement.  Putting up your stacked, black cans between a couple south facing windows and venting into the house would probably give you more total heat gain.