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solar / wind power without a battery?

 
pollinator
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I'm interested in utilizing solar power but I have little to no experience with electricity, except for plugging something in and turning it on. I already use passive solar in that the north and west of my house is mostly underground and the south is mostly windows.

Anyway back to solar without a battery, might it be possible to run some kind of heating element directly from the panel. Maybe embed that element in some kind of masonry construct just like you might do with a fireplace or RMH. Effectively storing the energy as heat rather than electricity?

If you could ditch the controllers, converters and batteries it would be much cheaper to use solar for heating. Could something like a water heater coil or even an electric stove burner buried in a pile of bricks be utilized like that? If so I could buy panels equal or greater in size to my windows and  greatly increase my solar gain by heating up my thermal mass.

If wind could be utilized that way as well those cold winter winds at night and on cloudy days would be turned into heat producers.

Even without any heat at all, it would already take several days of very cold weather to actually freeze inside my house. If I could boost the passive heating and heat storage some, maybe even double it with a system like that, it would be well worth it.

 
pollinator
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If you go to the builditsolar.com site, they have passive solar water heater projects that work very well and might be better for what you are doing.  It's very inefficient to try to use a solar panel to create electricity and then use it to create heat, rather than just using the sun's energy for heat in the first place.

This page has a lot of options for doing what you are trying to do. Build It Solar
 
pollinator
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I did this with the element out of an old bread machine and I heated water with it.

You have to match the current of the panels to the coil for the best results  I added and took away  panels till I got the best results for the coil I had.  

I did not pursue this, The big down side is if you remove the electrical connection with DC there is a large spark, I did this with jumper cables for my test.




There are devices out there that are sold that match the coil to the solar panels to yield max energy from the panels.        Good info on them on Youtube.
 
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Over at Living Energy Farm they are running all kinds of things on "Daylight drive." I think their hot water comes from direct solar. But most of their electrical equipment just runs when the sun is shining.

They have been experimenting with PV heat for cooking.

 
pollinator
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12 volt DC water heater elements are available over the counter. People use them as a "dump load" -- when their batteries are full, the controller transfers the unneeded energy to the heater element to heat water.

For space heating? It's the most expensive, inefficient heat source I can imagine.

 
pollinator
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That video about the hot water heating of panel collector vs solar panels was quite interesting, thanks for posting that! I was surprised that the solar could produce more power on a price metric, but then, panel prices have come down a LOT. It was also based on a commercially built collector, and I suspect that a DIY version could be made a lot more economical. Especially if you are only trying to achieve temperatures of 70-80F.

To respond the OP, I would say that solar panels ONLY for heat probably is not the optimal solution in terms of cost or collector area. It sounds like you want to drop batteries to save cost (and this is indeed a big savings); but that also suggests that budget is the main criteria. In that case, I think the cheapest way to pump heat into your house would be with black-painted boxes covered in recycled window glass. You would need a little pump, a bunch of black poly pipe, some antifreeze, and maybe a reclaimed radiator to dump the heat inside. You can get cheap little temperature relay controllers that could sense the temperature of the collector to only run the pump when there was heat to recover. I bet you could make a proof-of-concept for a few hundred bucks, and you could scale it up to a real monster of a system for not a whole lot more.

Then again, if you really like the idea of getting some solar panels, here is another option: Get a big array, a tiny battery, and a diversion controller. These controllers maintain the battery voltage during charging not by lowering the solar input, but by ramping up and down an external load. They are a necessity for hydro and wind where you cant simply shut off the incoming power. It doesnt really matter how big the battery bank is, once its full, it will just run the dump load. A controller will run you about 150 bucks, this is one that I have used for this:
https://www.amazon.com/Xantrex-Charge-Controller-Solar-Generators/dp/B000OZ385A
You could just hook it to a big wirewound resistor like this:
https://www.amazon.com/TE1000B1R0J-Wirewound-1000W-%C2%B1440ppm-Bracket/dp/B00W2YQ0QK/ref=sr_1_6?keywords=wirewound+resistor+1000w&qid=1637269098&qsid=136-0514627-8926456&sr=8-6&sres=B07WZ9LTWW%2CB07WPQ2XMC%2CB07WPQ2MXT%2CB00W2YQ0QK%2CB07WYV9P2B%2CB01AA6PGC0%2CB011OZ1378%2CB00MNE0RPO%2CB09KNWMZXQ%2CB09KNV5VLG%2CB09KNTDYQC%2CB072BL2VX1%2CB07SPC8CKK%2CB07WF98SVW%2CB07TLWH927%2CB07D54XMFK
The battery could be a single 12v deep cycle that you can get for about 100 bucks at any battery place.
Since you will hardly use it, the battery would likely last for a very long time, and if the power ever goes out, you could put a 20 dollar inverter on it, and at least have some lights and backup power. Youd be looking at about 300 dollars for the battery, controller and dump load, plus the panels. If you look on craigslist you can sometimes find used panels for a very good price.
 
Mark Reed
pollinator
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Thanks, everyone. Given me lots to think and read about. Sounds like my idea of burying a stove burner in a metal bucket of sand and running the wires off a solar panel to it might not be a good idea. On the other hand I'm stubborn and generally have to fail at something myself to accept it won't work. Even though it sounds like there is little to no chance it will.

How about with wind? That might be even better as it often blows at night and sometimes in the dead of winter it blows hard. I read that solar panels are only at best about 20% efficient at converting the sun's energy to electricity, wow, I was kind of shocked at that. Are wind turbines any better?

I don't really expect to heat the house to a comfortable level with this idea. Just wondering if there are ways to add to the passive solar gain of my south windows and heavy insulation in the walls and roof to further reduce the need for fire wood. If I had know about RMH when I built the house I might have one but that ship has sailed.
 
Jeremy VanGelder
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A cavitation heater can turn rotary motion (from a windmill) into heat. It was discussed on this thread.

And this guy built one. webpage
 
When people don't understand what you are doing they call you crazy. But this tiny ad just doesn't care:
Rocket Mass Heater Manual - now free for a while
https://permies.com/goodies/8/rmhman
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