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matt sexton
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I'm working on this 'solar horno' idea, would love constructive feedback. Discussion is helpful, hopefully adds momentum and direction.

I live in Albuquerque, plenty of sun here. As Steve Baer says, "so much sun here you can do your passive solar project poorly and it will still work"

In the south west, we have these things called "horno"s, it's a 5' tall thermal mass with a chamber inside. In the morning you build a fire inside, around noon you scrape out the coals and put in the bread dough. This is the traditional bread baking method. It takes a lot of wood!

Solar Horno:

A thermal mass surrounded by insulation. With a shut-able hole in the top, and a tracking solar concentrator above the hole funnels photons down into the hole. Every day about 15 mega-joules heats up the mass inside, raising the mass temperature to 2000F, hence plenty of energy storage. Simple convective channels trickle the heat to a cooking chamber as needed.

I did the fun (for me) part, I figured out how to cut a piece of sheet metal up so as to form an arbitrarily large Fresnel lens for concentration. Haven't built one yet, that's the next step, but I'm bound and determined to build one an see how it works.

The parts I'm not sure about yet: passive tracking, kiln-like materials for solar mass and cooking chamber.

I want a solar cooking spot in the yard, be able to cook marshmallows, heat up a big pot of water for pasta, slow-cook meat, all by grace of the long-set sun.

Thoughts?
 
allen lumley
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Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
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Matt Sexton : From where I am sitting up here in the soon-to-be fridge-ed Northeast This is some original thinking, this is where
new ideas come from, Welcome to Permies.com With over 25,000 fellow members world wide, you can come here 24 / 7 and find
someone who wants to talk about what you want to talk about! They will stretch your mind as you are stretching theirs

Heat rises -find some way to apply your heat at the bottom not at the top, otherwise you leave a channel for the heat energy
you are trying to store to escape !

It may be necessary to bend your mind more to the more conventional oven for that reason alone ! Please consider going to ->

www.ernieanderica,info/shop

From that page scroll down to the double chambered oven, From the pictures alone -in your location, you should be able to create
a high temperature oven that will need only a little additional wood fuel to give you all you are seeking !

From that place as a starting point it will be interesting to see where you go next ! Big Al

P.S. I am sending you a purple message ,just click on that Icon !
 
matt sexton
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Hi Al, thanks for the thoughts. Yes, heat rises, so it does seem like a good idea to shine the light in at the bottom. That puts the concentrator and/or mirrors next to the oven instead of above it. Which I might well do.

Have you made one of those 'high temperature' ovens? How hot do they get inside? How do you form the perlite insulation layer, is it a wet mix that dries into shape, or is it something you carve into shape?

My direction is completely away from burning any wood.
 
matt sexton
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Al warned me in a pm, that I was not clear about something:

The sheet metal lens I spoke of is a light-goes-through lens. Concentric rings of metal are tilted so as to deflect the light towards a focus that is down-light from the lens. This is not a parabolic mirror.
 
allen lumley
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Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
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Matt Sexton Is being kind, when i finished schooling there were only 3 states of matter, not 5 or 6, and a lens was something that light
shines through, today physics appears to say a lens is anything that focuses or bends light ! ( and I may not have that right ! )

Ernie and Erica Wisner our moderators of the Rocket Mass Heaters and Wood stoves have also built several two chamber outdoor Cob/
Adobe ovens that when brought to temperature (with wood) can cook for hours. This is what I would attempt to modify !
Goto-> the forums section and find

permies >> forums >> energy >> wood stoves click on wood stoves and find and click on double chamber cob oven watch the
1st video and check out the rest of this forum thread ! you can follow the prompts to buy the plans at Permies.com or goto ->


www.ernieanderica.info/shop and scroll down to the Two-Chamber Earthen Oven (with chimney) plans !
This will get you to something that is capable of double duty working both off of the sun and still continue to work well as a
conventional cob oven with much lower fuel usage to boot ! ( I Think ! )

While buying plans gets you a chance to talk with ernie or erica, they will both be working this month at the secret lab in Montana !

This will get you to the point that you can come back here and talk to other members who have experience with the E & E cob oven
I think if you can follow along with these steps you will soon be breaking new ground! where the rest of us have not gone. Good luck!

Think like Fire, Flow like a Gas, Don't be the marshmallow! As always, your comments and questions are solicited and Welcome Big AL
 
allen lumley
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Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
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Matt : add Kiko Denser to the list of very knowledgeable people that a google search for will give you useful information. You will carry most of the weight for this
project, but with over 25,000 fellow members world wide -you will find people here at Permies.com who want to talk about what you want to talk about ! Big AL
 
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