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The Problem Half the world’s people must burn wood or dried dung to cook their food.Half the world’s people must burn wood or dried dung to cook their.

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Presentation on theme: "The Problem Half the world’s people must burn wood or dried dung to cook their food.Half the world’s people must burn wood or dried dung to cook their."— Presentation transcript:

1 The Problem Half the world’s people must burn wood or dried dung to cook their food.Half the world’s people must burn wood or dried dung to cook their food. Nearly 1.2 billion people, a fifth of the world’s population, do not have access to clean drinking water.Nearly 1.2 billion people, a fifth of the world’s population, do not have access to clean drinking water. Over 1 million children die yearly because of un-boiled drinking water.Over 1 million children die yearly because of un-boiled drinking water. Wood cut for cooking purposes contributes to the 16 million hectares of forest destroyed annually.Wood cut for cooking purposes contributes to the 16 million hectares of forest destroyed annually. Half the world’s population is exposed to indoor air pollution, mainly the result of burning solid fuels for cooking and heating.Half the world’s population is exposed to indoor air pollution, mainly the result of burning solid fuels for cooking and heating.

2 “I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait ‘til oil and coal run out before we tackle that.” Thomas Edison

3 Overview Types of cookersTypes of cookers Principles of solar cooker designPrinciples of solar cooker design Retained heat cookingRetained heat cooking Cooking guidelinesCooking guidelines Teaching ideasTeaching ideas ExamplesExamples Additional information and resourcesAdditional information and resources

4 Types of solar ovens Box CookerBox Cooker Panel CookerPanel Cooker Solar Funnel CookerSolar Funnel Cooker Parabolic Cooker - not recommendedParabolic Cooker - not recommended

5 Box cooker Among easiest and most popular to build and use Lid of a cardboard box reflects light onto pots under glass Advantage of slow, even cooking of large quantities of food

6 Panel Cooker Sunlight is reflected off of multiple panels onto a pot under a glass lid or in a bag Can be built quickly and at low cost Many different varieties

7 Solar Funnel Cooker Safe, inexpensive and easy to use Concentrates sunlight into a dark pot in a plastic bag Combines best of parabolic and box cookers Anyone can make one

8 Parabolic Cooker Highly focused light and high temperatures Cooks nearly as fast as a conventional oven Costly and complicated to make and use – have to turn frequently to follow the sun Potentially hazardous-not recommended

9 The basic principles - C.A.R.E.S. C ollect the lightC ollect the light A bsorb the lightA bsorb the light R etain the heatR etain the heat E ase and EfficiencyE ase and Efficiency S afetyS afety

10 C: Collect the Light Collect the sunlight using reflectors with an approximately 400 square inch opening (20x20)Collect the sunlight using reflectors with an approximately 400 square inch opening (20x20) Easy way to measure: the minimum opening of the cooker needs to be the diameter of an adult’s armEasy way to measure: the minimum opening of the cooker needs to be the diameter of an adult’s arm Reflective surface materials include: aluminum, Mylar, aluminized Mylar of any thickness, aluminum or chromium paint (Note: mirror like reflectors can lead to eye damage)Reflective surface materials include: aluminum, Mylar, aluminized Mylar of any thickness, aluminum or chromium paint (Note: mirror like reflectors can lead to eye damage)

11 A: Absorb the light Absorb the light – paint the pot matte black or another dark color to absorb the heatAbsorb the light – paint the pot matte black or another dark color to absorb the heat Pots can also be elevated by a wire base or posts, allowing the bottom of the pots to collect sunlightPots can also be elevated by a wire base or posts, allowing the bottom of the pots to collect sunlight

12 R: Retain the Heat Retain the heat – hot vessels lose their heat to the air quickly so they need to be coveredRetain the heat – hot vessels lose their heat to the air quickly so they need to be covered Cover with plastic, glass, Plexiglas, or tempered glassCover with plastic, glass, Plexiglas, or tempered glass A tight lid will trap steam and speed up cooking Ex: Canning jars work like inexpensive pressure cookersA tight lid will trap steam and speed up cooking Ex: Canning jars work like inexpensive pressure cookers

13 R: Retain the Heat A note on plastics Oven bags are the best way to retain heat. They are sold in most large U.S. grocery stores, although they may be hard to find in other places (Reynolds © bags work well)Oven bags are the best way to retain heat. They are sold in most large U.S. grocery stores, although they may be hard to find in other places (Reynolds © bags work well) If you can’t find oven bags, an alternate solution is transparent High Density Polyethylene bags (HDPE)If you can’t find oven bags, an alternate solution is transparent High Density Polyethylene bags (HDPE) Prevent the HDPE bags from touching the pots or jars, as they may meltPrevent the HDPE bags from touching the pots or jars, as they may melt Avoid polyethylene – it melts too easilyAvoid polyethylene – it melts too easily Good plastic may be the most difficult material to find, and may require extra planning, possibly including importing the oven bagsGood plastic may be the most difficult material to find, and may require extra planning, possibly including importing the oven bags

14 E: Ease and Efficiency Ease – simplicity of everyday use Funnel and box cookers are the easiest to use – they don’t have to be turned to follow the sunFunnel and box cookers are the easiest to use – they don’t have to be turned to follow the sun Efficiency - how fast the cooker heats food Parabolic cookers focus light to a point (most efficient) causing dangerous conditionsParabolic cookers focus light to a point (most efficient) causing dangerous conditions Funnel cookers focus light across a broader area down the center of the cooker (efficient but not dangerous)Funnel cookers focus light across a broader area down the center of the cooker (efficient but not dangerous)

15 S: Safety S afety – Avoid highly focused light such as that in the parabolic cooker. It can damage eyes and start firesS afety – Avoid highly focused light such as that in the parabolic cooker. It can damage eyes and start fires Always exercise caution with cookers. Sunglasses are useful when looking into a cookerAlways exercise caution with cookers. Sunglasses are useful when looking into a cooker Cooking pots are hot and should be treated as though they were on a stove-topCooking pots are hot and should be treated as though they were on a stove-top

16 Remember - C.A.R.E.S. C ollect the lightC ollect the light A bsorb the lightA bsorb the light R etain the heatR etain the heat E ase and EfficiencyE ase and Efficiency S afetyS afety

17 Retained Heat Cooking If sunlight is lost or multiple items need to be cooked, there is a solutionIf sunlight is lost or multiple items need to be cooked, there is a solution Once the food is heated, quickly transfer to either:Once the food is heated, quickly transfer to either: - an insulated box or set of towels, - or an insulated hole in the ground covered with more insulation with more insulation The food will continue to cook for hoursThe food will continue to cook for hours

18 Temperatures Sunny Day: heats from °C ( °F)Sunny Day: heats from °C ( °F) Cloudy Day: heats from °C ( °F)Cloudy Day: heats from °C ( °F) Hot enough to pasteurize water (at least 65-70°C for 20 minutes)Hot enough to pasteurize water (at least 65-70°C for 20 minutes) Hot enough to fully cook meats, breads, grains, vegetables, etc.Hot enough to fully cook meats, breads, grains, vegetables, etc. Kills disease-causing bacteriaKills disease-causing bacteria

19 Impact Expect solar ovens to replace 60% of fuel needs in most placesExpect solar ovens to replace 60% of fuel needs in most places The other 40% of the time, due to inclement weather or special types of food, traditional methods can still be usedThe other 40% of the time, due to inclement weather or special types of food, traditional methods can still be used Doesn’t replace fire as a way to heat homesDoesn’t replace fire as a way to heat homes

20 Approximate Cooking Times Vegetables: 1.5 hrsVegetables: 1.5 hrs Rice/wheat: hrsRice/wheat: hrs Beans: 2-3 hrsBeans: 2-3 hrs Meats: 1-3 hrsMeats: 1-3 hrs Bread: hrsBread: hrs See Recipe File for more details and cooking ideas

21 Costs and benefits Cost: approximately $2/cooker depending on location and availability of materialsCost: approximately $2/cooker depending on location and availability of materials Materials include cardboard, aluminum foil, plastic bag, etc. See Building Instructions for more details and be creativeMaterials include cardboard, aluminum foil, plastic bag, etc. See Building Instructions for more details and be creative BenefitsBenefits –Saves cost of fuel or time spent gathering wood –Prevents diseases from impure water –Ecologically friendly

22 **Teaching Ideas** Give construction seminarGive construction seminar Can accompany current educational programs such as hygiene, gardening, or English/literacyCan accompany current educational programs such as hygiene, gardening, or English/literacy Takes as little as half a day trainingTakes as little as half a day training Train a group to teach others--little efforts can achieve large impactsTrain a group to teach others--little efforts can achieve large impacts Remember: Focus on training and sustainability rather than handoutsRemember: Focus on training and sustainability rather than handouts

23 Real World Examples Summer 2003 Fernando successfully taught solar cooking classes in northeast Brazil with Help InternationalSummer 2003 Fernando successfully taught solar cooking classes in northeast Brazil with Help International Four solar ovens transform a Chilean village (see packet)Four solar ovens transform a Chilean village (see packet) Microenterprise case study in packetMicroenterprise case study in packet

24 Food for Thought Solar cookers can be a used for micro-enterprise and other business ventures:Solar cookers can be a used for micro-enterprise and other business ventures: –Build and sell cookers –Cook and sell bread or other foods –See packet for examples and suggestions Adapt to local cultures and customsAdapt to local cultures and customs

25 BE CREATIVE and HAVE FUN! You can improvise with most of the techniques and materialsYou can improvise with most of the techniques and materials Remember the basic principles (CARES) and you can adjust for the skills and resources of those who will make and use the ovensRemember the basic principles (CARES) and you can adjust for the skills and resources of those who will make and use the ovens

26 Step-by-Step Instructions –Funnel Cooker Instructions included on this CD –Box Cooker are at in both the box cooker section and with pictures in the slide show –For more construction ideas see Alternative Cookers PowerPoint also on this CD

27 Additional Resources Recipe File on this CDRecipe File on this CD Packet of articles also on this CD includingPacket of articles also on this CD including –Background information –Case-studies –Ideas for micro-enterprise –Frequently Asked Questions –Contact list of NGOs using solar technology

28 Comprehensive Internet Site Internet Site For questions or feedback contact Dr. Steven Jones at Brigham Young UniversityFor questions or feedback contact Dr. Steven Jones at Brigham Young University – –Phone: (801) Additional Resources


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