Let me just say – there’s something incredibly satisfying about cooking a meal with the power of the sun. Harnessing the power of sun’s rays to slow cook or grill a meal gives me a welling sense of pride. I enjoy using human ingenuity to capture a little bit of the sun to put warm food in my belly. And I like knowing that if the power grid were to go down for a long time, I’d still have a way to cook a meal.
Sure, you could cook a meal using fire, but solar ovens don’t require any “extra” resources.
It’s using the “free,” virtually unlimited, readily available fuel and putting it to good use.
It also makes me feel good to lower my carbon footprint.
That’s why I like to cook some of my meals with the sun, and I bet some of those reasons are why you’re here reading this now.
So today I want to share with you everything I know about solar cooking, specifically:
- Why You Should Cook With Solar
- What Is A Solar Oven Exactly
- Different Kinds Of Solar Cookers (And How To Build Them)
- Magnifying Glass
- Fresnel Lens
- Reflector Cooker
- Box Cooker
- Parabolic Mirror
- Parabolic Trough Cooker
- Solar Ovens Worth It?
WHY YOU SHOULD COOK WITH SOLAR
It’s hard to go more than a day without hearing about the benefits of solar power.
The news is full of stories about solar panels and how they’re making self-sufficiency a reality for many homeowners.
- For some, it’s possible to pair panels with batteries to get off the grid entirely.
- For others, the panels are tapped into the electrical grid to help offset electrical use.
Either way, these large solar systems are still expensive and often still requires a professional installer. Because you’re dealing with high voltage electricity – which means DIY is recommended.
But while solar electricity gets the most attention, there are many more ways to harvest the sun.
For example, my neighbors in college had a solar hot water heater on the south side of the house.
It was a series of vacuum tube pipes that allowed them to pre-heat the water going into their hot water heater. This setup cut down how much they spent on their steaming hot showers.
It was a passive solar heated system, with no moving parts or electrical connections.
That simplicity was what I thought of when I started looking into solar ovens and solar cookers.
And even if you have solar panels, you should still look into solar ovens and cookers.
Why? Because converting the sun’s rays into electricity to run an oven is inefficient.
It takes vast sums of the suns power to power it long enough to cook a meal.
And while gas and wood stoves are reliable, they require nonrenewal (costly) fuels such as fossil fuels or wood.
A solar oven allows you to cut the cord, pass on fossil fuels AND leave the woodpile behind!
The bottom line is:
Solar ovens make you more self-reliant.
And if you’ve read some of our other articles (such as solar generators, solar phone chargers, and portable solar chargers) you know we love solar for survival, preparedness, and self-reliance!
WHAT EXACTLY IS A SOLAR OVEN ANYWAYS
We all get uncomfortable lounging in the direct sunlight for long periods of time.
In the blazing summer, you can literally “cook” your skin – it’s called a sunburn!
The sun releases vast amounts of energy in the form of electromagnetic radiation.
This radiation includes visible light as well as both infrared and ultraviolet radiation.
In fact, more than half of the solar energy that reaches the Earth comes in the form of infrared radiation. We feel the infrared waves on our skin as heat – a great example of radiant heat transfer.
What if you could concentrate that hot sun into a smaller space?
If you’re picturing a big magnifying glass, that’s a great example of a simple solar cooker.
From this basic design, solar ovens and cookers branch out into all sorts of unique designs.
But they all have the same purpose:
To concentrate as much infrared radiation as possible into an enclosed, insulated space. Then to trap this building heat to allow for cooking.
Why are we more concerned with infrared waves than visible light?
Well…because of physics.
Infrared waves are FAR more efficient at heating things up.
Clear materials (like glass) allow radiation to pass through but not reflective ones. Opaque ones absorb infrared light and convert it to thermal energy.
The darker the surface, the more pronounced the effect. So flat black painted cookware can really help with efficiency.
So by focusing more infrared radiation on solid foods (or a cooking container) will heat it up faster.
THE DIFFERENT TYPES OF SOLAR COOKERS (AND HOW TO BUILD THEM)
As I said earlier, a magnifying glass can work as a solar cooker.
However, it’s generally pretty small, and it takes a lot of work to focus the light on an object.
I wouldn’t count on heating up much more than a few grains of rice at a time with a handheld magnifying glass.
And by the time you scaled it up large enough to be useful, the lens would be so heavy and bulky it wouldn’t be worth carrying.
Stick to using a magnifying glass as a fire starter instead of a solar cooker.
So pass on this type of solar cooker.
Stepping up from a magnifying glass is a Fresnel lens.
Fresnel lenses are good at directing light. In fact, they were used for hundreds of years in lighthouses to focus light out to ships at sea.
You can find plenty of Fresnel lenses for sale on Amazon, both in glass and plastic.
While a large Fresnel lens is excellent at focusing solar energy, it does so at a relatively small point. And they are highly sensitive to the angle of sunlight.
This means that a Fresnel lens solar cooker will be efficient, but they need a lot of tending.
I built one with a 24” lens, and it’s compact, lightweight, and durable.
It’s powerful enough to boil a pot of water quickly. But due to the small focus point, it’s difficult to use in cooking larger items.
However, it can be done with some ingenuity (watch the video below).
Outside of cooking, it’s also a very capable firestarter – and I’ve even used it to melt scrap lead!
Leaving behind lens designs, many people interested in solar cookers turn to reflectors.
Simple reflector solar cookers can be built with flexible solar shields. Like the reflectors you see inside the windshield of many cars.
For under $20, you can pick up all the materials necessary to build your own.
These designs can be incredibly lightweight and compact in a pack. Plus, they’re among the only solar cookers that would travel well on foot.
Commercial models are available that use much more durable materials and improved cooking surfaces.
Paired with heat-resistant cookware, these make an excellent solution for solar cooking!
A box cooker can be as simple as a cardboard box lined with aluminum foil.
I’ve seen pizza boxes converted to solar cookers that were effective and super cheap.
It won’t fry an egg, but it can hit slow cooker temperatures.
If you want something more efficient, check out the Sun Oven.
The solid wood box is well insulated, with a dark painted interior to absorb heat and a clear top to trap it inside.
The side panel mirrors focus more energy into the box, allowing it to hit 200-300deg easily.
I haven’t had a chance to use one of these, but I think I might build one this winter for use on camping trips next summer.
The plans looks straightforward and easy to follow.
If you’re not into DIY, go with a Sun Oven.
It features an efficient reflector and aiming system. This helps to concentrate all available solar energy into the solar cooker.
They can reach temperatures that rival your standard in-home oven. So they’re capable of baking loaves of bread and cooking meats.
A parabolic mirror reflects light off a curved surface and back to a focus point in the middle.
Their shape is like a satellite dish or an umbrella. Both of those items can serve as the base to build a parabolic mirror cooker.
Like a Fresnel lens, a parabolic mirror focuses its energy on a tiny spot. This can make cooking larger items difficult.
However, it’s much less sensitive to sun angle, making it a more hands-off design than the other lenses.
Parabolic mirrors come in all kinds of materials and sizes. You can even build your own with a few things out of your survival cache now!
As with all solar cookers, size matters and a larger mirror will collect more energy and cook faster.
Some segmented parabolic mirrors provide a reflective surface several feet in diameter.
These mirrors are hard to DIY since the shape is crucial to focusing energy on the cooking pot.
Unless, of course, your neighbor tosses out their old 5-foot wide satellite dish! If so, snag it and get to work.
Parabolic Trough Cooker
A parabolic trough uses the same curved reflective surface as a circular parabolic mirror. But, it stretches that surface out along one axis into a long channel.
Instead of the single focal point, this creates a long line of focused energy.
If you align the trough with the path of the sun, it allows the light to be focused for hours without maintenance.
This hands-off time can really free up resources and make dinner prep a lot easier.
Like other parabolic mirrors, these are a much more challenging DIY build.
Instead, look at purchasing something like the GoSun Portable Solar Cooker.
This stove has a vacuum tube cooking chamber providing a near perfect layer of insulation, keeping heat in and cold out.
Perfect for cooking with small children while keeping the kitchen cool during the summer.
The Sun Kettle
Before we wrapped up this section on Parabolic Trough Cookers – there’s one last thing I wanted to show you.
Theirs a new product on the market that uses a dual parabolic trough design to boil water FAST.
It’s called The Sun Kettle.
As we all know boiling water is very useful in a survival or camping situation. It allows you to purify water.
But you can also cook a lot of different soups or boil hot dogs in water.
This is basically a dual parabolic thermos. So if you’re interested in this kind of solar cooker, we recommend you check out The Sun Kettle.
The vacuum insulated tube acts as a combination greenhouse and thermos. This gives this type of solar cooker an astounding efficiency.
So Which Solar Oven Is The Best?
“Best” is a very subjective word since each type has its own pros and cons.
It also depends on what you’re looking for.
Some solar ovens are easier to build (like the reflective oven or box oven) – while the parabolic trough cooker is not very DIY friendly.
Also, are you planning to travel with it? If so, the solar dish parabolic cooker is not a good option…
Here’s a good comparison video to watch from Tiny House Giant Journey that may help you decide:
SOLAR OVENS WORTH IT?
Clearly, solar cookers and ovens have some limitations.
As with any solar system, they depend on bright, direct sunlight to be effective.
This limits your cooking to daylight hours and decent weather.
Solar cooking is often slower than other cooking methods. This means you may have to be in camp for longer and plan your day around the timing of cooking tasks.
Due to the size of the cooking vessel, it may also be challenging to cook for a large group.
If you can work with these limitations, a clean, fuel-less cooking system has lots of benefits.
It’s silent, generates no smoke or soot, and can run as long as you have sunlight.
A lightweight solar cooker can often weigh less than a comparable traditional stove. Plus, it doesn’t need heavy, costly fuel.
While I wouldn’t likely make it my primary cooking system in the cloudy Pacific Northwest.
I’ve certainly come to enjoy using my Fresnel lens solar cooker.
And I plan to build and experiment with other designs in the future.