Tag Archives: cooking

Environment, food, Lifestyle

How To Make a Solar Powered Oven

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How can someone construct a solar powered oven locally? This really good question came from a reader of this blog in response to the post Solar Powered Cooking Oven. There are several good resources on building your own solar oven, and I’m going to summarize them here.

Start with a Black Box

Any kind of non-toxic, non-shiny waterproof box will work. A box with suitcase-size dimensions will allow you to use a medium-sized baking pan that is about 9 by 12 inches.

Next you will need to paint it black with a food-grade, heat-resistant paint. In a poor country, I’m not sure where you can readily find this kind of paint, but most hardware stores in developed countries sell oven paint. Paint the inside of the box thoroughly, air dry and give it a second coat. Air dry until the pain is cured and all of the gases are clear.

Add a Glass Lid

The glass lid does a few things: keeps the heat in, traps moisture and keeps critters out. Attach the glass to the box with a hinge on one side so that you can easily lift the lid. On the opposite side, attach rubber feet so that the glass will seal when closed. Finally add one or two small screw hinges or clamps that firmly hold the lid closed.

Reflectors

The reflectors gather the sunlight and focus it into your black box. You can use any sturdy outdoor material (i.e., plastic, wood, metal) as long as it’s waterproof. Cut four pieces, one the length of each side of the box and attach them to the top of the box. Cover them with a shiny, reflecting material. Aluminum foil or paint will work. Just make sure than reflecting surface is smooth and shiny.

Accessories

A few optional items will make the oven easier to use: a thermometer inside the oven, carrying handle, a swivel tray inside the box and an adjustable leg to raise and lower the oven to match the angle of the sun. If you can’t find these, the oven will work without them.

However, you need a non-reflective pan for cooking. It can be glass, cast iron or even teflon just as long as it’s not shiny. A shiny pan will reflect the heat away from your food, which defeats the purpose.

Alternatives

Another reader in India mentioned that she uses a parabolic cooking dish like the one shown above to capture sunlight and slow-cook food. You cannot fry or bake on high heat, but the design is much simpler. It is literally a curved dish with the depression in the center. So if you can’t find the materials locally to make your own solar oven, try a parabolic cooking dish.  You might even try recycling an old satellite dish, cover it with reflective material and voila!

Good luck and let me know how yours turns out!

Environment, Family, Lifestyle

Solar Powered Cooking Oven

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Solar cooking ovens are an inexpensive and easy way to make every day Earth Day. Since I have owned mine, I have experienced lower energy bills, reduced carbon footprint, a cooler kitchen during summer, set and forget cooking and delicious tasting food. They are inexpensive, low-tech and downright amazing.

I live on solar power (“off grid”) and recently asked my in-laws for a new solar cooking oven as my Christmas gift. I initiated my new solar oven with a batch of dark chocolate brownies. The oven works better than I expected.

There are many good brands of solar cookers on the market that range in price from $100 to over $400. My solar oven came from Sun Oven and cost about $300. It was really simple to set up and very easy to use. Like regular ovens, you can use a solar oven for cooking, baking, braising and heating water. It will heat up to 450 degrees.

Set Up

The first step is to unfurl the reflectors and secure them with the built-in pin. Next position the oven so that shadows fall evenly on both sides. Look closely at this picture below. The shadows are not even on both sides. A quick adjustment of the oven to the right would even out the shadows, causing more direct light and a higher oven temperature.

The second step is to adjust the tip-tilt angle of the oven. For this adjustment, you will need to consider the overhead angle of the sun. At higher latitudes, the sun is typically lower in the sky at noon than at lower latitudes. Here in Hawaii during the summer, the sun is almost directly overhead so tipping is not needed. But when tipping is needed, there is a swivel pan inside the oven that conveniently levels itself.

To recap, simply unfurl the reflects, position the oven so that the shadows are even on both sides and tip the oven to match the overhead angle of the sun. The built-in thermometer will gauge the heat as you make adjustments.

Set and Forget

For quick recipes, like brownies that take 30 minutes or less, you can set the oven and forget it. As an devoted foodie, I have been nothing but delighted at how the food tastes – it’s more moist and tender. A solar oven is ideal for braising meats and baking breads. It’s easy enough for children to use, too.

One key accessory is a non-reflective pan, such as one made of glass or cast iron. For baked goods, like brownies, I use a glass pyrex pan as shown below. For meats, soups and stews, I use a cast iron dutch oven.

Plus, the solar oven doesn’t heat up my house. On a hot summer day, it’s possible to use less energy (and save money) by avoiding the conventional oven and extra air conditioning. In Hawaii where our electricity rates only increase, a solar oven will easily pay for itself within a few months.