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==Types==
 
The three most common types of solar cookers are [[box cookers]], curved concentrators ([[Parabolic cookers|parabolics]]) and [[panel cookers]]. Hundreds — if not thousands — of variations on these basic types exist. Additionally, several large-scale solar cooking systems have been developed to meet the needs of institutions worldwide.
 
   
[[Image:Box-type.jpg|left|girl with box cooker]]
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{{Updated|1|28|15}}
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==How do solar cookers work?==
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Most solar cookers work on the basic principle: Sunlight is converted to heat energy, that is retained for cooking.
   
===Box cookers===
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Below is the basic science for [[solar panel cookers]] and [[solar box cookers]]. The other main variety of cookers are called [[parabolic solar cooker]]s. They typically require more frequent reorientation to the sun, but will cook more quickly at higher temperatures. They also have the ability to fry foods.
   
Box cookers cook food at moderate to high temperatures and often accommodate multiple pots. Worldwide, they are the most widespread. There are several hundred thousand in India alone. See [[:Category:Solar box cooker designs|Solar box cooker designs]].<br clear="all" />.
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[[File:Solar_Cooking_basics,_SCI_2004,_pg._1,_12-9-14.png|none|600px]]
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*A solar cooker needs an outdoor spot that is sunny for several hours and protected from strong wind, and where food will be safe. Solar cookers don't work at night or on cloudy days, though during the best months for cooking, many foods can be cooked under intermittent clouds or a light haze, as long as food is put out early and there is definitely more sun than not overall.
   
[[Image:Parabolic-type.jpg|right|woman with parabolic cooker]]
 
   
===Parabolic cookers===
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[[File:Solar_Cooking_basics,_SCI_2004,_pg._2,_12-19-14.png|none|600px]]
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===Converting sunlight to heat energy===
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At its simplest, the sunlight-to-heat conversion occurs when photons (particles of light) moving around within light waves interact with molecules moving around in a substance. The rays emitted by the sun have a lot of energy in them. When they strike matter, whether solid or liquid, all of this energy causes the molecules in that matter to vibrate. They get excited and start jumping around. [[Principles_of_Solar_Box_Cooker_Design#Heat_gain|This activity generates heat]].
   
Curved concentrator cookers, or "parabolics," cook fast at high temperatures, but require frequent adjustment and supervision for safe operation. Several hundred thousand exist, mainly in China. They are especially useful for large-scale institutional cooking. See [[:Category:Parabolic solar cooker designs|Parabolic solar cooker designs]].<br clear="all" />.
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Dark surfaces get very hot in sunlight, whereas light surfaces don't. While food cooks best in dark, shallow, thin metal [[pots]] with dark, tight-fitting lids, there are many other containers that can also be used in a solar cooker.
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{{Main|Pots}}
   
[[Image:Panel-type.jpg|left|woman with panel cooker]]
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===Retaining heat===
   
===Panel cookers===
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A transparent heat trap around the dark pot lets in the sunlight, and keeps the heat that is produced from escaping. This is a clear, heat-resistant plastic bag or large inverted glass bowl (in panel cookers) or an insulated box with a glass or plastic window (in box cookers).
{{Main|Solar panel cooker designs}}
 
Panel cookers incorporate elements of box and curved concentrator cookers. They are simple and relatively inexpensive to buy or produce. Solar Cookers International's "[[CooKit]]" is the most widely used combination cooker. See [[:Category:Solar panel cooker designs|Solar panel cooker designs]].<br clear="all" />
 
   
==Principles==
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Light passes through the plastic bag or glass cover as a relatively short wavelength. Heat is reflected back as a longer wavelength, and does not easily pass back through the clear enclosure. This explains why cars left in the sun, especially those with black interiors, will slowly become hotter and hotter, even on days with low air temperatures.
Most solar cookers work on the basic principle: Sunlight is converted to heat energy, that is retained for cooking.
 
   
===Fuel: Sunlight===
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Parabolic solar cookers typically do not require a heat trap, as the light from the reflector is tightly focused on the cook pot. They cook at higher temperatures, but require more frequent reorientation with the sun than box or panel cookers.
Sunlight is the "fuel." A solar cooker needs an outdoor spot that is sunny for several hours and protected from strong wind, and where food will be safe. Solar cookers don't work at night or on cloudy days, though during the best months for cooking, many foods can be cooked under intermittent clouds or a light haze, as long as food is put out early and there is definitely more sun than not overall. Extra covers or simple foiled boosters can help under marginal skies.
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{{Main|Glazing}}
   
===Converting sunlight to heat energy===
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===Capturing extra sunlight energy===
Dark surfaces get very hot in sunlight, whereas light surfaces don't. Food cooks best in dark, shallow, thin metal pots with dark, tight-fitting lids to hold in heat and moisture.
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One or more shiny surfaces reflect extra sunlight onto the pot, increasing its heat potential. Mirrors, aluminum foil, mylar, mirror-finish metals, chrome sign vinyl, and other shiny materials have all been used successfully for solar cooking, depending on the type of cooker and the environment in which it will be used.
  +
{{Main|Reflective material}}
   
===Retaining heat===
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==Solar cooker types==
{{Main|Greenhouse effect}}
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The three most common types of solar cookers are [[box cookers]], curved concentrators ([[Parabolic cookers|parabolics]]) and [[panel cookers]]. Hundreds — if not thousands — of variations on these basic types exist. Additionally, several large-scale solar cooking systems have been developed to meet the needs of institutions worldwide.
A transparent heat trap around the dark pot lets in the sunlight, and keeps the heat that is produced from escaping. This is a clear, heat-resistant plastic bag or large inverted glass bowl (in panel cookers) or an insulated box with a glass or plastic window (in box cookers). Curved concentrator cookers typically don't require a heat trap.
 
   
===Capturing extra sunlight energy===
+
===<u>Box cookers</u>===
One or more shiny surfaces reflect extra sunlight onto the pot, increasing its heat potential. Mirrors, aluminum foil, mylar, mirror-finish metals, chrome sign vinyl, and other shiny materials have all been used successfully for solar cooking, depending on the type of cooker and the environment in which it will be used. See [[Reflective material]].
+
[[Image:Box-type.jpg|right|200px|girl with box cooker]]
  +
Box cookers cook food at moderate to high temperatures and often accommodate multiple pots, typically taking between one and three hours to cook various foods. Worldwide, they are the most widespread. There are several hundred thousand in India alone.
  +
{{Main|Solar box cooker designs}}
   
==See Also==
 
   
  +
===<u>Panel cookers</u>===
  +
[[Image:Panel-type.jpg|right|200px|woman with panel cooker]]
  +
Panel cookers incorporate elements of box and parabolic concentrator cookers. They are simple and relatively inexpensive to buy or produce. Solar Cookers International's "[[CooKit]]" is the most widely used combination cooker.
  +
{{Main|Solar panel cooker designs}}
  +
  +
  +
===<u>Parabolic cookers</u>===
  +
[[Image:AlSol 1.4.jpg|thumb|300px|An [[AlSol 1.4]] parabolic cooker demonstrates where the cook pot is supported to receive the focussed light from the reflector.]]
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The other main variety of cookers are called [[parabolic solar cooker]]s. They use a bowl shaped concentrating reflector to focus the light more directly onto the cook pot, usually from below. The parabolic name refers to the shape of the curve of the reflector cross-section.
  +
  +
They will require more frequent reorientation to the sun, possibly every 10 minutes, but they cook food more quickly and at higher temperatures compared to other solar cookers. They also have the ability to fry foods. They are especially useful for large-scale institutional cooking.
  +
{{Main|Parabolic solar cooker designs}}
  +
  +
==See Also==
  +
*[[Introduction to solar cooking]]
 
*[[Principles of Solar Box Cooker Design]] - ''[[Mark Aalfs]]''
 
*[[Principles of Solar Box Cooker Design]] - ''[[Mark Aalfs]]''
 
*[http://images2.wikia.nocookie.net/__cb20080215180446/solarcooking/images/3/3a/Pejack-on-solar-cooker-technology.pdf The Technology of Solar Cooking] - ''[[Ed Pejack]]''
 
*[http://images2.wikia.nocookie.net/__cb20080215180446/solarcooking/images/3/3a/Pejack-on-solar-cooker-technology.pdf The Technology of Solar Cooking] - ''[[Ed Pejack]]''
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==External links==
 
==External links==
*[http://www.humboldt.edu/~ccat/virtualtour/handouts/solar_cookers.pdf Parabolic Solar Cookers] -''Humboldt State University''
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*[http://www.ccathsu.com/files/uploads/Parabolic-Solar-Cookers.pdf Parabolic Solar Cookers] - ''Humboldt State University''
*[http://science.howstuffworks.com/solar-cooking.htm/printable How Solar Cooking Works] - ''HowStuffWorks''
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*[http://science.howstuffworks.com/environmental/green-science/solar-cooking1.htm How Solar Cooking Works] - ''HowStuffWorks''
 
*[http://solarcooking.org/kerr.htm The full text of the book The Expanding World of Solar Box Cooking] - ''[[Barbara Kerr]]''
 
*[http://solarcooking.org/kerr.htm The full text of the book The Expanding World of Solar Box Cooking] - ''[[Barbara Kerr]]''
 
*[http://solarcooking.org/research/Dormio-report.htm Evaluation of Several Original and Commonly Used Solar Cooker Designs] - ''Dane Dormio and Steven Jones''
 
*[http://solarcooking.org/research/Dormio-report.htm Evaluation of Several Original and Commonly Used Solar Cooker Designs] - ''Dane Dormio and Steven Jones''

Latest revision as of 23:39, January 28, 2015

Last updated: 28 January 2015      

How do solar cookers work?Edit

Most solar cookers work on the basic principle: Sunlight is converted to heat energy, that is retained for cooking.

Below is the basic science for solar panel cookers and solar box cookers. The other main variety of cookers are called parabolic solar cookers. They typically require more frequent reorientation to the sun, but will cook more quickly at higher temperatures. They also have the ability to fry foods.

Solar Cooking basics, SCI 2004, pg. 1, 12-9-14
  • A solar cooker needs an outdoor spot that is sunny for several hours and protected from strong wind, and where food will be safe. Solar cookers don't work at night or on cloudy days, though during the best months for cooking, many foods can be cooked under intermittent clouds or a light haze, as long as food is put out early and there is definitely more sun than not overall.


Solar Cooking basics, SCI 2004, pg. 2, 12-19-14

Converting sunlight to heat energyEdit

At its simplest, the sunlight-to-heat conversion occurs when photons (particles of light) moving around within light waves interact with molecules moving around in a substance. The rays emitted by the sun have a lot of energy in them. When they strike matter, whether solid or liquid, all of this energy causes the molecules in that matter to vibrate. They get excited and start jumping around. This activity generates heat.

Dark surfaces get very hot in sunlight, whereas light surfaces don't. While food cooks best in dark, shallow, thin metal pots with dark, tight-fitting lids, there are many other containers that can also be used in a solar cooker.

Main article: Pots

Retaining heatEdit

A transparent heat trap around the dark pot lets in the sunlight, and keeps the heat that is produced from escaping. This is a clear, heat-resistant plastic bag or large inverted glass bowl (in panel cookers) or an insulated box with a glass or plastic window (in box cookers).

Light passes through the plastic bag or glass cover as a relatively short wavelength. Heat is reflected back as a longer wavelength, and does not easily pass back through the clear enclosure. This explains why cars left in the sun, especially those with black interiors, will slowly become hotter and hotter, even on days with low air temperatures.

Parabolic solar cookers typically do not require a heat trap, as the light from the reflector is tightly focused on the cook pot. They cook at higher temperatures, but require more frequent reorientation with the sun than box or panel cookers.

Main article: Glazing

Capturing extra sunlight energyEdit

One or more shiny surfaces reflect extra sunlight onto the pot, increasing its heat potential. Mirrors, aluminum foil, mylar, mirror-finish metals, chrome sign vinyl, and other shiny materials have all been used successfully for solar cooking, depending on the type of cooker and the environment in which it will be used.

Main article: Reflective material

Solar cooker typesEdit

The three most common types of solar cookers are box cookers, curved concentrators (parabolics) and panel cookers. Hundreds — if not thousands — of variations on these basic types exist. Additionally, several large-scale solar cooking systems have been developed to meet the needs of institutions worldwide.

Box cookersEdit

Box-type

Box cookers cook food at moderate to high temperatures and often accommodate multiple pots, typically taking between one and three hours to cook various foods. Worldwide, they are the most widespread. There are several hundred thousand in India alone.


Panel cookersEdit

Panel-type

Panel cookers incorporate elements of box and parabolic concentrator cookers. They are simple and relatively inexpensive to buy or produce. Solar Cookers International's "CooKit" is the most widely used combination cooker.


Parabolic cookersEdit

AlSol 1.4

An AlSol 1.4 parabolic cooker demonstrates where the cook pot is supported to receive the focussed light from the reflector.

The other main variety of cookers are called parabolic solar cookers. They use a bowl shaped concentrating reflector to focus the light more directly onto the cook pot, usually from below. The parabolic name refers to the shape of the curve of the reflector cross-section.

They will require more frequent reorientation to the sun, possibly every 10 minutes, but they cook food more quickly and at higher temperatures compared to other solar cookers. They also have the ability to fry foods. They are especially useful for large-scale institutional cooking.

See AlsoEdit

External linksEdit

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