Solar Cooking

This is my latest creation. I built the outside shell out of plywood which is sealed with polyurethane. This cooker is kept outside all of the time except when there might be rain. Normally I use one reflector. This setup is good for about 90% of the time. If I really want high temps (close to 400) I install the other three reflectors. In the pictures I have the cooker setting in the winter mode for when the sun is lower on the horizon. This cooker is very versatile and we use it all year long for all kinds of cooking. If you look closely you'll notice similarities to the Hallacy oven from "Cooking With The Sun", the Sun Oven, and the ULOG cooker.

The above oven gets extremely hot. This cooker is basically the Heaven’s Flame with the top angled and a reflector configuration like the “Amazing Solar Oven”. I can achieve 410 degrees easily with this oven and I’ve had it up to 420 in January with outside air temps in the 40’s. Amazingly, the glass is only one layer of single strength window glass and it’s never cracked.

The Minimum. This one has a couple extras including slanted inner walls and double glazing. Easy to build, works great, cheap, nuf said!

Here's a spreadsheet to calculate the proper angle for any length of reflector or glazing (aperture) size. This is for use in designing box cookers.

Now this is a great cooker. I built this with 24 individual petals made out of cardboard glued together along the edges. The result is a surprisingly strong parabolic shape with an 8” focal point that I just bolted in between a scrap piece of shelving and a ½” flange. Using some electrical adapters, EMT, and aluminum I made a pot holder that just screws into the flange. It’s easy to build a parabola with any focal point and any diameter using this spreadsheet. I had water boiling at 9:00 am mst on the shortest day of the year using this cooker and pan shown in the left picture with no cooking bag or insulation to protect the pan from temps in the 30’s.

Although this looks like the "Solar Stove Top Cooker” when finished, it’s actually quite different. My design is similar to the one at the bottom of this click here page. Most notably, I used parallel ribs instead of ribs radiating out from the center. Mine is parabolic instead of a section of a sphere so the focal point can be made to be whatever you want. Last, mine is 40”x40” with a 16" focal point. Notice on the second picture the obvious focal point. I was able to generate enough heat, at around 10am, to get the EMT red hot. The third picture shows the result of the heat and exactly where the rod needs to be cut off for the pot holder.

This cooker works fantastic but because of its larger size, maneuvering it around is awkward for everyday use. Also, it's very strong with no sign of the cardboard sagging even after 2 years of hanging on a wall in my garage. If you’re interested in this design try this spreadsheet out. This spread sheet will allow you to design the parabola with any focal point and any reflector size. I think this design is a little easier to build than the “Solar Stove Top Cooker” model.

If you download a spreadsheet and don't understand it, contact me and I'll walk you through. One of these days I'll write some easy to follow instuctions.

The Solar Cooking Archive

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