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New 12 Sided Cooker

 
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Bill Bradley



Joined: 26 Nov 2006
Posts: 21
Location: Springfield MA USA

PostPosted: Sat Jul 07, 2007 12:54 am    Post subject: New 12 Sided Cooker Reply with quote

We have developed and built a prototype of a new twelve sided coker.
The twelve sided EB30D is a 30 inch (76.2 cm) diameter cooker. Apparently twelve sided cookers were first reported by Tran http://solarcooking.org/plans/DATS.htm and later refined by Paradesi http://www.angelfire.com/80s/shobhapardeshi/twelvesided.html. Both Tran and Paradesi located the pot at the bottom of the cooker where the cooker primarily heats the top and sides of the cooking pot. We believe that our cooker will cook more efficiently because we have located the pot near the mouth of the cooker so that the cooker primarily heats the bottom and sides of the pot. An advantage of the 12 sided cooker over the double cone cooker is that it may be easier and less time consuming for the do it yourselfer to build. for more information on this cooker see our website http://www.earthboundtech.com
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marquitusus



Joined: 09 Jul 2007
Posts: 4
Location: spain

PostPosted: Wed Jul 11, 2007 7:11 am    Post subject: Drawings low resolution Reply with quote

Hi Bill,
I find interesting your solar cooker.
I wanted to make one, but the plans published in your web page are not of sufficient resolution, so I am not able to see the numbers.
Could you send me, or post, the same drawing with higher resolution?

Thanks,
MARC
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marquitusus



Joined: 09 Jul 2007
Posts: 4
Location: spain

PostPosted: Wed Jul 11, 2007 7:14 am    Post subject: Drawings low resolution Reply with quote

Hi Bill,
I find interesting your solar cooker.
I wanted to make one, but the plans published in your web page are not of sufficient resolution, so I am not able to see the numbers.
Could you send me, or post, the same drawing with higher resolution?

Thanks,
MARC
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coconino



Joined: 21 Nov 2006
Posts: 77
Location: Sunny Brixton

PostPosted: Sun Jul 15, 2007 10:22 pm    Post subject: Reply with quote

This cooker looks good. I've passed the link to a friend who is interested in this type and will let you know any results.
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marquitusus



Joined: 09 Jul 2007
Posts: 4
Location: spain

PostPosted: Mon Jul 16, 2007 7:52 am    Post subject: 12 sided constructed Reply with quote

Hi Bill,
This weekend I build your 12-sided design. The construction process was good, but I had some stability problems. I didn't build the support, because I haven't got wood nor iron to do it. It was a windy day, so the cooker, the stand and the pot were on the floor very quickly.
I like these designs, because they are more efficient than DATS or Parvati. BUT, if I had to recommend one desing, I don't would recommend yours, because it is absolutely necessary to build the support. In DATS or Parvati, it is not necessary, one can place the pot in simple ways, using, for example, a flowerpot stand.
This is, I think, the main advantage of Cookit: it stands alone in the ground!
Maybe, a parabolic reflector that don't need complex support could be designed.

MARC
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Bill Bradley



Joined: 26 Nov 2006
Posts: 21
Location: Springfield MA USA

PostPosted: Thu Jul 26, 2007 1:24 am    Post subject: Revised Drawings of Cooker Cone Reply with quote

We have revised the drawings of the cooker cone on our web site. This should make them easier to understand and use. The drawing of the cone layout has been revised and a new drawing of one of the twelve cone segments has been added.

Bill Bradley
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Bill Bradley



Joined: 26 Nov 2006
Posts: 21
Location: Springfield MA USA

PostPosted: Thu Jul 26, 2007 2:14 am    Post subject: Support for Cooker and Pot Reply with quote

Hi MARC
You are absolutely right when you say that our cooker needs a stand to hold the cooker and the pot. Moving the pot to the mouth of the cooker makes the cooker more efficient, but the pot must be supported. The DATS and Parvati cookers can get by without a stand for the cooker, but they benefit from a stand. Without a stand, it is difficult to adjust these cookers for different sun elevation angles, and the wind may blow them over. If you look in the "New Developments" section of the website on the Parvati cooker, you will see that Ravindra Paradesi is using a stand for his new cookers.

You are correct that an advantage of the CooKit is that it does not require a stand and the pot sets firmly on a flat surface. I built a CooKit and have cooked meals in it. However the CooKit has a much lower concentration ratio, and can not be adjusted for different sun elevation angles. It takes much longer to cook food in a Cookit than in a cooker like ours. I personally think that solar cookers will be more readily accepted if they cook more like the kitchen stove, and that our cooker is a step in that direction.

Bill Bradley
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coconino



Joined: 21 Nov 2006
Posts: 77
Location: Sunny Brixton

PostPosted: Thu Jul 26, 2007 9:42 am    Post subject: Re: Revised Drawings of Cooker Cone Reply with quote

Bill Bradley wrote:
We have revised the drawings of the cooker cone on our web site. This should make them easier to understand and use. The drawing of the cone layout has been revised and a new drawing of one of the twelve cone segments has been added.


The drawings are indeed much clearer to read, thank you. I really want to make one of these!

Can you say something about why the dimensions are so precise? Your arcs are accurate to a hundredth of a degree (i.e. less than an arc minute) which seems unlikely to be achievable outside a sophisticated engineering workshop.
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coconino



Joined: 21 Nov 2006
Posts: 77
Location: Sunny Brixton

PostPosted: Thu Jul 26, 2007 10:02 am    Post subject: Re: Support for Cooker and Pot Reply with quote

Bill Bradley wrote:
I personally think that solar cookers will be more readily accepted if they cook more like the kitchen stove, and that our cooker is a step in that direction.

It does indeed look very useful in that respect. A modern western household includes several complementary methods for cooking and nobody expects one method to suit all purposes. Why should we expect solar cooking to be any different? Our domestic kitchens include an oven, grill and hob with each suited to a different type of cooking. We also have microwave ovens, electric kettles, bread-makers, toasters, etc., and outdoor cooking is done on purpose-built barbecues.

We are so used to this variety of cooking tools that we hardly think about it. Wanting to make tea, one is unlikely to boil a kettle in the oven; when baking a cake one wouldn't think of using the burner on the hob. Naturally - and choosing without difficulty - we use the appropriate tool for each job. (Of course, what is considered appropriate is also to some extent a cultural matter, but regardless of culture, soup is not cooked in a grill.)

A parabolic reflector is better suited to cooking with bottom heat (frying or rapid boiling); a box cooker is better suited to stewing and baking. I don't see these as mutually exclusive but see each as part of the solar kitchen tool kit. It has taken millennia to evolve the domestic kitchen we know today, so I would expect it to take a while to settle the form of the solar kitchen, especially as the solar vernacular is so different from what we are used to. Experiments like yours are really exercises in creating a new set of tools and helping us all to understand what works in different circumstances.
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Bill Bradley



Joined: 26 Nov 2006
Posts: 21
Location: Springfield MA USA

PostPosted: Mon Jul 30, 2007 1:20 am    Post subject: Precision of Dimensions and Angles Reply with quote

Quote:
Can you say something about why the dimensions are so precise? Your arcs are accurate to a hundredth of a degree (i.e. less than an arc minute) which seems unlikely to be achievable outside a sophisticated engineering workshop.

The precision of the dimensions and angles shown on our website are simply the default precision of the drawing program we used. In fact, most of the dimensions are not too critical. We rounded each dimension to the nearest sixteenth of an inch. Small errors will only slightly change the shape of the cooker and probably not effect its performance significantly. We used an ordinary ruler for marking the dimensions and did the cutting with a utility knife. The angles are given mostly as a check and really are not necessary for laying out the cooker.

Bill Bradley
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whisk



Joined: 02 Sep 2007
Posts: 5

PostPosted: Sat Dec 29, 2007 9:28 am    Post subject: 16-sided *triple* angled cooker? Reply with quote

To Bill Bradley,

Was looking to build the most efficient (ie. closest to a paraboloid) possible cooker from cardboard & aluminum. (I'm doing a project in Tanzania, and aluminum sheets are expensive here.) Therefore, I was wondering whether you think it is possible to construct a 16-sided *triple*-angled cooker?

Thank you very much in advance for the information.
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whisk



Joined: 02 Sep 2007
Posts: 5

PostPosted: Sat Dec 29, 2007 9:31 am    Post subject: 16-sided triple angled cooker? Reply with quote

To Bill Bradley,

Was looking to build the most efficient (ie. closest to a paraboloid) possible cooker from cardboard & aluminum. (I'm doing a project in Tanzania, and aluminum sheets are expensive here.) Therefore, I was wondering whether you think it is possible to construct a 16-sided *triple*-angled cooker?

Thank you very much in advance for the information.
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micsolaire



Joined: 03 Oct 2009
Posts: 7
Location: Lambesc (13) south France

PostPosted: Sun Apr 04, 2010 9:46 pm    Post subject: Reply with quote

Some photos of the 16 faces from Earth bound Tech





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Location : 43 38.847 " N - 5 15.9... E Alt : 242 m
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Bill Bradley



Joined: 26 Nov 2006
Posts: 21
Location: Springfield MA USA

PostPosted: Mon Apr 05, 2010 1:52 am    Post subject: Reply with quote

Thanks for posting the pictures. It is good to know that our cooker designs are being used.
Bill Bradley
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micsolaire



Joined: 03 Oct 2009
Posts: 7
Location: Lambesc (13) south France

PostPosted: Mon Apr 05, 2010 9:13 am    Post subject: Reply with quote

Bill,
Thanks for sharing the drawings of this cooker.
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