Solar furnace for lime and bricks

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dedeleco
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by dedeleco » 03/04/12, 22:38

I add the curve of the maximum output as a function of the temperature of the oven receiving sunlight, for various concentration ratios C, on the inlet of the oven.
With Stefan's constant of radiation equal to 5,65W / m at 100 ° K and 460W / m2 at 300 ° K, (26 ° C) almost half of the solar radiation of 1000KW / m2 taken with an emissivity of one, difficult to have less , since almost all metals oxidize at 900 ° C, except Au and Pt, which are very expensive.
To reach 900 ° C, comfortably you need a concentration factor C from 200 to 250.
With C = 100 we do not reach 900 ° C.

Image

http://en.wikipedia.org/wiki/Concentrated_solar_power
http://en.wikipedia.org/wiki/Stefan-Boltzmann_law

A concentration of 200 to 250, requests 250 mirrors with precision all directed on a single opening of oven of the same dimension, either on a single parabola, or all controlled at the same time, in heliostat as in Odeillo.
It is not very easy.
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chatelot16
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by chatelot16 » 04/04/12, 22:49

Sourdois wrote:Here are the elements on the ovens and current production:
- Ovens constructed of baked bricks
- Capacity: 20 tonnes of quicklime on average
- Average wood consumption: 100 steres
- Cooking time: 1 week without interruption
- Quality of the stones: CaO of 56,4% on average; average block size 30x50cm
- Lime production in 2010: 25 tonnes


given bizarre 25 ton per year with an oven that makes 20tonnes? it means that it only works one week per year

a solar oven that would work every day should only do
25t / 365 = 68kg

say 100kg / days

another way of seeing: it is a shame to build a large satellite dish only to make lime: it would be even better to run a thermal machine to make electricity, for all purposes, and lime also by moving slightly between the lime kiln and the steam boiler which will make the electricity

electricity will be used among other things to operate a crusher to break the limestone before cooking it

the cooking of the lime can be interrupted anytime depending on the need for electricity

it is the same thing with the pyrolysis of solar wood: a parabola can be used in priority to make electricity and be turned to pyrolysis when there is too much electricity

mirrors are expensive: you have to use them as much as possible to try to be profitable

for lime my preference is to crush the limestone to cook it very quickly, but you have to quantify the energy consumed by this grinding, and the price of the grinder

if it is justified to make a big oven with a large thermal inertia to cook pottery without it getting too cold at night, this big oven can also be used to cook limestone in large pieces

even if the construction of a large slow furnace seems to me unprofitable for lime, if it is justified for bricks and pottery lime can complete its use
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dedeleco
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by dedeleco » 05/04/12, 02:19

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by chatelot16 » 07/04/12, 15:29

this discussion allows me to clarify another idea:
a good solar dish can make a temperature much higher than what is needed for a heat engine in materials not too expensive

it is therefore interesting to use 2 once the heat! in the day the sun heats an oven and limestone ... in the evening a thermal machine cools the lime and the oven by making electricity at one o'clock or the solar collectors do nothing more
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dedeleco
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by dedeleco » 09/04/12, 03:54

Here is what to copy in simpler:
solar furnace melting steel:
http://www.youtube.com/watch?v=8tt7RG3UR4c


Inexpensive dishes that heat a lot, even melting steel:
http://www.youtube.com/watch?v=1RNNlYiK ... re=related

A valid solution at high concentration 5000 times small size suitable for making lime in small quantities at a time from a satellite dish in epoxy fiberglass covered with glued and carefully oriented mirrors (larger 250 sufficient instead of 5800 for 900 ° C):


Area of ​​dish aperture (elliptical) = (pi x 102cm x 73cm) / 4 = 5848 sq cm
Area of ​​focal point (circular) = pi (0.6cm) ^ 2 = 1.14 sq cm
Concentration Power = 5848 / 1.14 = 5129 then rounded down
Output Power Estimate = 560 watts


It is probably the simplest as a starting point, with the addition of a simple solar tracker to 2 motors controlled by LEDs, taken from:
http://www.redrok.com/electron.htm#led3x
site full of varied achievements.


After tuning from 1 to about 2m, it is possible to make larger following the same principle with larger mirrors, but remaining as simple in structure.

The larger but also simple version:
http://www.youtube.com/watch?NR=1&featu ... TvAL7ty53M

There are also lots of varied possibilities from simple to very big on:
http://www.greenpowerscience.com/
http://www.youtube.com/watch?v=1RNNlYiK ... ure=relmfu
http://www.youtube.com/watch?v=TtzRAjW6 ... re=related


Also with large Fresnel lenses:
this one makes lime with limestone on 1cm2 very quickly (80cm square, concentrated on 1 cm2 approximately)
http://fresnel.biz/1.html

http://www.youtube.com/watch?v=eZx4XRk6 ... =fvwp&NR=1


and a very simple but less precise solution:
SOLAR DEATH RAY WATER with 1 / 3 Kilowatt Heat Energy
http://www.youtube.com/watch?v=eeSyHgO5 ... re=related
good to burn with just a plastic sheet and water, good for the sun vertically!
You can make very inexpensive lentils for cooking by trapping water, gel or oil, between two plastic sheets, one rigid flat and the other flexible curved, which allows to orient the lens sufficiently , for cooking in the kitchen without burning wood.
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by dedeleco » 09/04/12, 12:29

An interesting realization in Mali with the help of French people who realized it, and their contact addresses, which can be improved and enlarged to make 900 ° C for hot oven working every day of accessible size as realization locally:

http://www.solarfire.org/Photos-Mali-2009

contacts:
Mali
Djadié Samake: tel. + 223_76_29_39_76
France
Florian Reynaud: florianreynaud7 (at) hotmail.com
Marie Testud: ptit_marie (at) hotmail.com
Thibaut Desreumaux: thibaut.desreumaux (at) hei.fr
Thimothée Rusca: timo_rusca (at) hotmail.com



http://www.solarfire.org/Drawings
http://www.solarfire.org/Details
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gus
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Re: Solar oven for lime and bricks




by gus » 15/11/17, 22:49

Hello,
it is with a few years of delay that I answer this message because I just came across it by chance.

The Mont Louis solar oven (https://www.pyrenees-cerdagne.com/sites ... -louis.pdf) studied a solar oven for firing ceramics in Morocco. As a demonstration, they brought Moroccan potters who made pottery using the experimental furnace. The project apparently did not succeed, Morocco having chosen to create a gigantic solar power station (https://fr.wikipedia.org/wiki/Centrale_solaire_Noor)

I discussed 4 years ago with officials who confirmed to me that it was possible to adapt their project to the manufacture of lime.


(Is it a little too late now?)
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chatelot16
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Re: Solar oven for lime and bricks




by chatelot16 » 15/11/17, 23:11

there is a big difference between baking pottery and making lime!

to cook pottery you have to do a well controlled temperature cycle to cook without breaking, and for large pieces the cycle lasts longer than a day of sun so solar cooking is impossible, you need another source of heat for at night, the sun can only be a way to save another energy

to make lime is much simpler ... there is no requirement for regularity of heating! when it heats it makes lime ... when it no longer heats it does not do more but just wait for the next day ... the lime already made does not suffer from cooling
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gus
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Re: Solar oven for lime and bricks




by gus » 15/11/17, 23:32

that is why the studies carried out could be used for the manufacture of lime in Haiti. The limestone resources are important, but the forests have disappeared.
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Re: Solar oven for lime and bricks




by thibr » 12/06/21, 13:25

obviously this is starting to be usable ... : Wink:


After APALA and Enerlog, the Low-tech Lab's investigations lead us to discover NeoLoco, near Rouen in Normandy!
Arnaud Cretot, its founder, is today a craftsman-engineer. On the one hand, a baker and solar roaster, on the other hand, designer of professional Lytefire concentrating ovens and a veritable open-air laboratory for the development of new associated practices.

Based on an original oven concept, simple and easy to manufacture anywhere, developed by Solar Fire Concentration, he has developed:
✅ recipes that change our culinary habits: from salted grain bread for aperitifs, including spices or coffee
✅ a transformation laboratory equipped in line with its quest for energy sobriety
✅ organization and techniques adapted to daily life
✅ a robust and resilient legal and economic model
✅ a distribution network in short circuits,
which show a new type of low-tech craftsmanship.

And the good news is that its model has already been made appropriable and replicable through Solar Fire France, which has the ovens manufactured to order by the boilermakers of CPM Industries in Le Havre, and is helping new “solar-preneurs” to find their way. launch on their territory, as is the case of Lydiane Tyrel in Auvergne Rhône Alpes and Luc Fournaux in the Pyrénées Orientales.

All the content produced as a result of this field survey is available on the website article dedicated to the survey.
https://lowtechlab.org/fr/actualites-blog/enquete-2
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