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How to Make and Use a Solar Oven | Box Cooker Plans and Recipes

What Exactly Is a Solar Oven?

A solar oven, sometimes referred to as a solar cooker, is a device that allows you to cook food using the sun's energy as fuel. The most common kinds of solar cookers are curved concentrators (also known as parabolic cookers,) panel cookers, and box cookers. Curved concentrators resemble a mirrored satellite dish. They cook at high temperatures, but require frequent adjustment. Panel cookers combine elements of a curved concentrator and a box cooker.

Homemade solar oven designs range from simple, inexpensive cookers that can be made in an hour, to complex systems that can cook at higher temperatures. One uncomplicated panel cooker design uses an automobile sunshade reflector to concentrate sunlight onto a black surface to cook food. Solar box cookers reflect and collect heat into a box, in which multiple cooking pots can be placed. This article will show you how to make a simple box cooker using common household supplies.

Is it really possible to cook with the sun? Yes! With a few simple adjustments, almost any recipe can be cooked in a solar oven. This article will show you how to make, use and enjoy a solar oven. Included is a solar oven construction plan that is easy to follow and can be constructed from simple materials on one day. I will provide tips along the way to make the process even easier and your oven more efficient. Solar cooking recipes links are included so that you can begin to enjoy the benefits of using a solar oven right away.

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Parabolic or Curved Concentrator Cooker

Parabolic or Curved Concentrator Cooker

How Do Solar Cookers Work?

First, heat must be collected. Sunlight is the fuel. In order to use sunlight, it must be collected and converted to heat energy. Dark surfaces get very hot in sunlight, so it is recommended to cook in a black, shallow pot with a tight lid to hold in the heat and moisture.

Next, heat must be retained. A transparent heat trap around the dark pot lets in sunlight and keeps in the heat. Types of wraps include clear, heat-resistant oven bags, inverted glass bowls, clear plastic or window glass.

Finally, increase and concentrate the heat. Shiny surfaces can reflect more sunlight onto the pot, increasing the potential for heat.

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What are the Benefits of Solar Cooking?

There is a rise in interest in solar cooking, with good reason! Solar cooking has many benefits.

  • Solar cooking saves fuel and is environmentally benign. It uses the power of the sun, which is a free, renewable resource.
  • Solar cooking saves money spent on utility bills for fuel. And your kitchen stays cool on hot days!
  • Slow cooking in a solar oven retains moisture, flavor and vital nutrients. Scientific evidence shows that foods cooked at a moderate temperature may be healthier.
  • Solar cooking is easy. Solar ovens do not burn foods, so no periodic or constant stirring is necessary. Foods cook virtually unattended.
  • Pots used to cook in a solar oven are easy to clean, with no burned on spots or sticky cooking oil film caused by high temperature cooking.
  • There is no risk of smoke, fire, or carcinogenic burning of food. There is very little danger to children.
  • Solar cooking is versatile, portable and wonderful for camping.
  • Solar ovens do not depend upon electrical or gas power. Solar cooking is a skill everyone should know for emergency food cooking, as well as water and milk pasteurization.
Solar Box Cooker with Added Reflectors

Solar Box Cooker with Added Reflectors

What Can I Cook in a Solar Oven?

Almost anything! Fruits, vegetables, meats, grains, even bread and desserts! A solar oven functions like a slow cooker, so it is able to cook roasts, casseroles, soups and other items that would normally be prepared in a crock pot. It can dehydrate foods, such as dried fruits, herbs and meats. It can also function like a conventional oven, giving you the ability to bake breads, cakes and cookies. Rice, beans and even pasta can be made in a solar oven, though they take a longer to cook than they would on the stove top.

Solar cookers do not get hot enough to boil liquids, stir-fry, sear meats or to bake pancakes and other flat breads. However, water can be pre-heated in a solar oven so that it boils quickly on the stove-top, and foods such as pasta and rice that are generally cooked by boiling can be prepared in a solar oven at a lower temperature. Meats can be seared or browned on the stove, and finished cooking in a solar oven with a tender, juicy result.

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Photo credit: KnowledgePublications.com

Is Solar Cooking for You? - Solar cooking may be a great way to cook if you can answer "yes" to the following questions.

Do you have mostly sunny days several months of the year?

Do you have a sunny space outside that is protected from wind and tampering?

Are you willing to experiment and learn a different way of cooking?

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What do you think?

The best time to use a solar oven is when our shadow is shorter than you.

The best time to use a solar oven is when our shadow is shorter than you.

When is the Best Time to Use a Solar Oven?

Any time that the length of your shadow on the ground is shorter than your height, the sun is high enough to cook. The sun is most intense between the hours of 10:00 am and 2:00 pm, which are prime solar cooking hours. However, a solar oven can be placed in the sun early in the morning, in order to begin heating up, and a well-insulated, hot oven will cook for an hour or two later than 2:00 in the afternoon.

The sun's angle as it moves across the sky can effect solar cooker temperatures. The angle of the sun is highest during summer months, but in many places, solar cooking can be done during most of the year.

How Much Longer Do Foods Take to Cook in a Solar Oven?

In general, you will need to add one hour to your conventional cooking time. Approximate cooking lengths for different types of food can be found in the following PDF file (you will need Adobe Acrobat to open the link:) How to Make, Use and Enjoy Solar Cookers.

The cooking times provided in the publication are approximate because solar cooking is not as uniform as conventional cooking. Many factors can affect the speed of solar cooking, including the following:

  • Time of year: cook times are longer in the winter than they are in the spring and fall, and cook times are shortest during the summer.
  • Amount of sun: Cloudy days require longer cook times than sunny days.
  • Amount of wind: Wind dissipates heat, which causes the oven to cool and require a longer cook time.
  • Type of pot: a large pot will take longer to heat than a small pot. An insulated pot also takes longer to heat up than a pot made of thinner material. Black pots heat up faster and hotter than light-colored or shiny, reflective pots.
  • Amount of food: Larger amounts of food take longer to heat up and cook than smaller amounts of food.
  • Amount of water: Water takes a long time to heat in a solar oven. A lot of water means a longer cooking time. In general, solar cooking requires less water than stove-top cooking.
  • Orientation of the Cooker: A cooker that is moved periodically throughout the day to follow the sun will cook faster than a cooker that is not facing directly directly towards the sun.