I love the idea of using the sun's energy directly, no pollution, no waste and no (energy) cost, it's fun to experiment with to dry or cook food or generate electricity and helps you become more independent from the power grid. Ten years ago I became interested in solar cookers, they are the obvious answer for when you have no fuel to cook your meals with, you want to increase your level of self sufficiency, do something good for the planet or you just want save money. It was one of those ideas that was just so good!
After a quick trip around the net I found www.solarcooking.org with plenty of low or no tech plans for building solar ovens and after some consideration I decided I wanted to build solar box cooker, this is basically one cardboard box inside another, with a clear panel to let the sun in (construction details to follow). It was mind bogglingly, cheap and easy to build, real alternative technology ...............and it worked like a heap of crap!
I made it as per instructions, tried to cook a number of dishes using several different food containers and the best that I could do was attain 60°C and that was in full sun! All it would do was warm the food and after a full day in the sun I still had to do most of the cooking in the gas oven.
The principle or theory that I was working on was that the inside box was insulated by then outside box and the inside box was then lined with aluminium foil to reflect the sunlight back onto the cooking pot once it had made it through the clear panel. So much for that theory! So I put it away in the shed and forgot about it for a while.
After doing some more searching on the net I found a small footnote on another website where a bloke who had been experimenting on his own account said that the secret was to have thin walled, matt black painted cooking pots and a matt black steel panel in the bottom to absorb the heat. This heat was then passed on to the cooking pot, in direct contact with it by conduction. This was exciting stuff and sounded like a serviceable new theory, but would it work?
Well, I put in a matt black steel panel and believe it or not, it did! All of a sudden I could get up to 90°C and was able to cook an aluminium billy full of spuds perfectly in less than two hours. This technology made sense and worked fine if you set it up right. So before I get too carried away, here is how I made the no-tech solar oven –
All it took was a couple of hours work and very little outlay (mostly for the oven bag) and I had raised my level of self reliance a notch! Well worth a go..... and as I said at the start - if I can do it, anyone can.
After the success of this one I put together a more complicated Reflecting Solar Box Oven