This week Earth Notes concludes its series on the sun with a look at how to use a backyard solar oven. You can use one anywhere there’s a few square feet of sunny exposure on a backyard or balcony.
And yes, you can use a solar oven on some winter days. Even when it’s cold and the ground is covering with snow, a cooker will work if you have enough sunshine and your solar oven is well insulated. But you’ll need to use the midday hours when the sun is at least 45 degrees above the horizon—that means your shadow is shorter than your height.
Prime solar cooking days occur when the sun is up that high for four hours or more. In Northern Arizona that’s around 170 days a year.
There’s more incoming ultraviolet radiation to cook with at high elevation, but that’s offset by lower atmospheric pressure, which requires longer cooking times. If you can tilt your cooker so that the sun's rays strike at a direct angle you’ll maximize cooking potential.
There are three main types of solar cookers: simple boxes with reflective lids, those with panels to focus sunlight, and sophisticated parabolic designs. For best results, use thin-walled, lidded, shallow cooking pots made from aluminum or steel with blackened outer surfaces.
Visit the KNAU website to find solar cooking links and ideas. With a little patience you can cook foods such as stews, chili and veggies effectively, even in some of the cooler months.
Visit http://solarcooking.wikia.com/wiki/Solar_Cookers_World_Network_(Home) to find a wealth of information about how to buy, build, and use solar ovens.