Solar Cookers and Solar Ovens have been around a long time, and out of the many ways to prepare food, solar cooking/baking is the least controversial. Think about it; boiling kills nutrients, frying clogs your arteries, microwaves, and ovens can emit radiation. If you decide to go raw, both your digestive and immune systems will have their hands full!
While there is no doubt that solar cooking has its drawbacks, the idea of preparing clean, nutrient-filled food that doesn’t break the bank or cause air pollution (by releasing fossil fuels) is appealing. This is why solar cookers and solar ovens are gaining in popularity.
Solar Cooker History
Even though some solar cookers and ovens might be considered new-age technology, they may explain how early man roasted and baked food before fire was used.
Despite its (probable) early discovery, it wasn’t until 1767 that Horace de Saussure made the concept of ‘solar-baking’ popular with his debut solar oven design. More than two centuries later, the world of sun-cooked food has greatly advanced and is still advancing.
What is a Solar Cooker?
A solar cooker is a cooking device made up of a collection of solar cells that trap sunlight energy and direct it towards cooking, baking, or sterilizing food. The devices vary in size and function/abilities, but all perform the similar task of using solar energy to process food in different ways.
Ultimately, the cooker (and its processes) aim to maintain the original nutrients in the food being cooked and reduce the cost of energy as well as reducing air pollution caused by other methods of cooking,
How Does Solar Cooking Work?
Even though solar cooking (purportedly) works by using solar energy to cook food, you might be surprised to learn that the sun’s heat isn’t what is at play in the solar cooker.
Sunlight radiation generates energy which is the result of variable magnetic and electric fields. Similar to the warmth that you feel when the sun touches your skin, the sun interacts with the molecules of the device which then generates the high temperatures that are needed for cooking.
Quite simply, the rays from the sun strike the device and cause activity, so both the sunlight and the cookers material have equal roles to play where solar cooking is concerned.
Types of Solar Cookers
There are various types of solar cookers depending on design and how you want to use them.
The Box Solar Cooker
Box cookers are often considered the most basic type of solar cookers. They are designed with an open-top box, reflective material, and transparent glass or plastic that usually sits on top of the box. The reflectors are positioned outside the box and are made of flat metallic/mirrored material capable of conducting heat, while the box is designed so that it can be closed to seal-up the heat trapped.
The pot is placed at the bottom of the box which is usually painted black to aid in heat absorption. Sunlight enters through the metallic/glass top and is absorbed though the reflective material. Much like an oven, the box traps the sunlight energy, generating heat and temperatures of up to 300 degrees Fahrenheit and cooking the food.
The Panel Solar Cooker
The Panel Solar solar cooker works by using reflective aluminum panels to direct sunlight towards a pot and generating heat. Although they are more frequently used in tropical regions or during warmer months, they are one of the most versatile types of solar cookers. The heat produced is mostly dependent on the size of the panels, making it possible to cook food in both low and high temperatures.
Despite its popularity, frequent sun exposure to the aluminum often causes these cookers to oxidize in a matter of weeks, so a solar cooker with stainless steel panels might be your best bet for aesthetic purposes – however, darker surfaces are known to heat faster. Whatever the case, you’ll get at least 200 degrees Fahrenheit with which to cook.
The Parabolic Solar Cooker
These solar cookers are popular for reaching temperatures that are high enough for frying and baking. The parabolic solar cooker is a popular choice among campers. The cooker works with a slightly more complicated design that uses curved and reflective surfaces to direct sunlight towards a small area, thus generating heat.
In this design, the pot sits at the middle of all the reflectors and is slightly elevated above the bottom of the cooker which is where the light is focused. The center becomes very hot and its molecules generate enough heat to move upwards and reach the bottom of the pot.
Because of its ability to reach up to 400 degrees F, this design poses some safety concerns – especially since the reflection can be damage the eyes. The cookers potential to cook quickly might result in charred food.
The Vacuum Tube Design (By GoSun)
The solar cooker by GoSun is a personal favorite of mine. Besides being the most portable of all the solar cooker designs available, it was also a 2016 winner of the popular CES innovation award.
The GoSun solar cooker is designed with a glass vacuum tube that is flanked in various directions by parabolic reflectors. With the vacuum holding the heat and the parabolic reflectors trapping it from the sun, the cookers temperatures can reach as high as 550F – the perfect grilling temperature.
The GoSun’s design doesn’t accommodate large quantities of food being cooked at once, but there is also the GoSun Grill which can be preordered and accommodates larger food quantities – much like the standard gas grill.
The Perks of Solar Cooking
Apart from being one of the cheapest cooking options available, solar cooking eliminates the need for a fire – which translates to cleaner air, eliminates food exposure to radioactive waves, and uses energy generated by a renewable energy source.
With more than 1 million people dying from air pollution yearly, several thousand from cancer, and a few others from lack of a means to sterilize water, solar energy may very well be the future of cooking.
Solar cooking solves the problem of pasteurizing contaminated water in rural areas and reduces the likelihood of deforestation due to firewood making. Overall, there is nothing quite as convenient as simply going outside and using the sun when the alternative involves expensive fuels and radioactive exposure.
Speeding Up Your Solar Cooker
For some solar cooker designs (like the parabolic solar cooker) you are more likely to worry about the food cooking too fast than too slow. If this isn’t the case, you might want to look for ways to optimize your solar cooker’s function. Here are a few steps you can take towards achieving the best possible solar cooking –
- Use Black Pots or Clear Jars
It is a long established fact that black pots/pans provide the best insulation when cooking with solar energy. If these aren’t available and there is no black paint with which to coat the utensils, your next best bet would be to use clear jars (typically the type used in canning). To avoid the possibility of an explosion, however, ensure that the lids are not tightly covered.
- Poke Holes in Your Box
This is especially useful for box cookers with glass reflective covers. The holes allow for the easy evaporation of condensation on the glass after cooking. Allowing condensed water to remain on the glass will likely make its reflective functions counterproductive. Also, remember to cover the holes using corks while cooking.
- Make a Reflector as Large as the Lid
With your reflector as large as the lid (and not just the size of the opening), you can optimize the concentration of solar energy being trapped, making more heat available during cooking. This will definitely come in handy while cooking during low sunlight days or in generally humid areas.
For Panel Cookers
- Enclose your Pots/Jars in Oven Cooking Bags
Apart from painting your cooking utensils black or using a clear jar, you can optimize the heat trapped by putting the pots or jars in oven cooking bags. This will help to concentrate the heat and make up for the condensation that might block the sunlight’s penetration.
- Position Your Cooker With The Sun’s Movement In Mind
Chances are, the sun will be making quite a few movements over the course of the day. If you intend to leave your cooking unattended, your best chance at getting optimum solar energy is to position your cooker in the direction that the sun is likely to face in the next hour or two.
Just a side note, panel cookers are known for making amazing soups and stocks.
Solar Cooking Without the Sun
The most important point to note about solar cooking in winter or humid days is that the heat of the sun can aid in cooking but isn’t necessarily a priority when it comes to solar cooking. No matter how cold or overcast it gets, the sun is likely to rise and set in order to provide illumination – the light that the sun provides is what is principal to solar cooking.
When light hits your reflective material, it ultimately causes its molecules to react and generate heat – while cold or humid days do not favor solar cooking, they certainly cannot deter it completely (at least, not in isolation).
Below are some points to consider when solar cooking in winter or on overcast days.
- Outdoor temperatures can only influence solar cooking to some extent. What will really count in the grand scheme of matter s is the quality of your solar cooker.
- Where winter sun isn’t particularly abundant, consider cooking small batches of food at a time.
- Solar box cookers are your best bet when cooking on days with low sunlight. This is because they are usually more insulated than other designs and are easier to incline in the direction of the sun.
- The sun typically moves more frequently across the sky on overcast or winter days. Solar cooking at this time would necessitate frequent turning of your solar cooker.
The Solar Oven
A solar oven is basically a solar cooker – at least by solar cooking standards. Solar ovens simply harness sunlight energy and channel it towards cooking food, baking, or pasteurizing. They are economical, efficient, and simple devices that are useful in underdeveloped countries or for lowering your energy footprint.
Is there a Difference between Solar Cookers and Solar Ovens?
The argument about whether or not solar ovens are different from solar cookers is common. The question has its roots in the definitions ascribed to conventional cookers and ovens. Cookers (or stoves) usually consist of heating plates or hobs while the oven is usually the insulated compartment often built into the cooker but aimed at performing a different function.
In solar cooking, the rules of conventional cooking devices do not apply, however, the parabolic solar cooker has often been argued to be the ‘solar oven’ of solar cookers. This is a little confusing in the context of a conventional cooker and oven, especially since it is difficult to associate a reflective dish to an enclosed oven.
Overall, we can agree that it is all solar cooking semantics when it comes to solar cookers and solar ovens. The two terms can easily be used interchangeably.
Before Buying a Solar Cooker/Oven
Like with other devices, purchasing a solar cooker is a slippery slope. Because the market is flooded with various options, it is important to consider the features you want before making a choice. Below are a few things to take into account.
The weight of your device will determine its maneuverability and versatility. While a cooker that is too light might easily succumb to wind, a cooker that is too heavy might prove to be a burden during movement. It might be important to consider a cooker with foldable features that can be easily reduced in size when not in use.
Ease of Assembly
Nobody likes a device that is hard to assemble. Take note that some panels require some sort of modification and a comprehensive manual may influence whether or not you make the purchase.
Availability of Spare Parts
Ultimately, you want a cooker that won’t break. Your best bet is to purchase something made by a well-known manufacturer, and that won’t be hard to fix depending.
In order to get the most out of your solar cooker, the reflective area that traps light must have sufficient breadth and width. One way to optimize the ability of the cooker to trap sunlight is to purchase a cooker that has a leveling feature. This feature allows the cooker to be adjusted to a suitable angle where it can trap sufficient sunlight.
Solar cookers and ovens have advanced over the years. They may be our cooking source of the future, and the future may be just around the corner.