Posted by & filed under Energy Systems, Processing & Food Preservation.

by Dr Samuel Alexander, co-director of the Simplicity Institute and a lecturer with the Office for Environmental Programs, University of Melbourne.

I was at the salvage yard the other day and saw some cheap mirrors, so I bought them. Not so that I could look at myself. From my typical appearance it is clear that I do not do that nearly as often as I should. Rather, I thought I could use them to make a good solar oven, and it turned out I could.

As you will see from the pictures, a solar oven works by concentrating the sun’s rays toward a central tub which heats up and thus functions as an oven. My solar oven consists of four mirrors, two cardboard sheets which I covered with tin foil, a black tub (a good colour for heat absorption), and the glass from a picture frame. Within the tub I placed a closed cooking pot with a glass lid. Total cost of these salvaged materials: $38.

I set it up at 10:30am and much to my surprise the cooking pot was too hot to touch in about half an hour. This was all the more surprising because the temperature in Melbourne today only reached 22 degrees (C) and there was scattered cloud for parts of the day. By mid-afternoon I had successfully cooked beetroots and carrots from the garden, as well as a bowl of red lentils. I chose beetroots and carrots due to their natural sugars, which were enhanced during the slow cook. Dee-licious. I look forward to experimenting with different foods (e.g. bread, pasta sauces, potatoes, cakes etc.) especially as we enter summer days reaching heats into the 30s and 40s.

Solar ovens are hardly a means of giving up your indoor oven. The sun is not always shining, and some foods probably won’t work so well. But when the sun is out and temperatures are moderate to high, solar ovens provide an easy, fun, and cheap way to reduce electricity or gas consumption in cooking. If everyone used such a device once or twice a week during the warmer months, fossil fuel consumption could be significantly impacted.

Further Reading/Watching:

4 Responses to “My Solar Oven: Renewable Energy the Simpler Way”

  1. Estrella

    Whoa, this is srsly terrific information! Commercial solar ovens cost a significant amount, hence I have so far hesitated to invest, being unsure that I would get around to using it enough to warrant the cost. This economy design means I have no excuses now, I will build one and perchance I don’t take to solar cooking, the worst case scenario is that I will have a house of mirrors. But what if the opposite happens, eh? Wouldn’t that be terrific? I am off to the dump and the second hand shops! Thanks Samuel!

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  2. A bear

    I’ve been meaning to get off my butt and build a passive solar hot water heater for a while, there are plenty of good designs as well as good common sense out there, but I shall definitely consider using these specific techniques as well. This would be sensational for a traveller up bush, the container would be a good carrier when not in use, and the rest pretty much flat packs.

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  3. Susan Kwong

    Samuel, your solar cooker is wonderful, I definitely need one! If ever the sun disappears, as it is sometimes wont to do in beautiful Melbourne, then transfer your cooking pot to a ‘haybox’, which is a fireless cooker made of a box with some kind of insulating material lining it, and a well-fitting lid to close, retaining the heat of your cooking vessel. The material used to be hay back in the day, and still can be, but I use an esky lined with old woollen blankets, which get packed in all around my pot. It works just like a slow cooker, but no ongoing fuel required :) I also use my ‘esky haybox’ to culture containers of yogurt after the mixture has been brought to the required temperature on the stovetop. Hmmm… now I’m dreaming of converting those purpose-built kitchen microwave spaces many houses have into permanent insulated haybox-type receptacles, always there awaiting your next soup, stew or yogurt :) People, time to ditch that microwave if you haven’t already done so! For a priceless read about fireless cookery, upload “The Fireless Cook Book: A Manual of the Construction and Use of Appliances for Cooking by Retained Heat (with 250 Recipes)”, published in 1909! Available from the Internet Archive http://archive.org/details/firelesscookbook00mitcrich

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