The power of the sun

Fire is useful but also potentially dangerous, even lethal. One need only consider the devastation from wildfires to realize the potential for damage. While hiking at Red Rocks Canyon midday, the blazing sun was a force to be reckoned with. On an exposed trail with limited shade, it doesn’t take long to overheat. Fire, sun, heat–sometimes good and sometimes bad.

While the star at the center of our solar system is far from the earth (93 million miles), the sun still provides an amazing source of energy. Who doesn’t appreciate having regulated heat: for cooking, staying warm, or ambiance around a campfire. It doesn’t seem like we take advantage of sunlight, a resource freely given.

This summer, I’m finally working on a project from my NUTs (Nagging Unfinished Tasks) list: building a solar oven. Simpler than a microwave oven or range, a solar oven is an insulated box with a glass lid, passively capturing heat from the sun. I built the box from scraps: pieces of plywood lined with an aluminum sheet and covered with insulated wrap. Leftover mirrors help direct the sun onto the dish to be heated and intensify the focus of the sun’s rays. A solar oven gets hot like a car does, an enclosed space when the sun shines in the windshield.

During World War II, soldiers would use vehicle engine blocks to warm their C-rations, sometimes even welding special holders for the cans. You do what you have to do to get warm chow. When we’re traveling, I find the dashboard of the car is actually a decent place to reheat a burrito or sandwich.

While relatively simple to build a solar oven, there were a few complications solved with guidance from YouTube videos. I learned how to disassemble and cut the aluminum frame from an old storm window and how to cut the glass to fit the box opening. As is typical for my projects, there was mission creep — the project expanded from just a solar oven. Since the direct sun shifts during the day, I had to move the oven’s location to optimize its use. A cart for the oven is a work in progress.

The hottest temperature I’ve observed is 200° Fahrenheit, which barely registered on the oven thermometer I placed in the box. But given that water boils at 212°, that is pretty hot. I needed oven mitts to remove the dish. Learning to cook using solar is another ongoing project. I’m testing different versions of Pyrex cookware with glass covers. Lesson learned — plastic is a bad idea– it will melt. A solar oven is not like a microwave.

You are probably wondering, “Why bother?” Well, partly because I can. The solar oven came in handy when we got home from vacation and our microwave was broken. On sunny days, it lets us heat food without using the stove, although it does take prior planning.

I’m a fan of renewable energy including solar. We have panels on the roof that augment energy from the grid. Strategically placed motion-sensor lights provide safety and security around the house. Using and positioning solar lights inside is a bit trickier to make sure that the batteries stay charged. I am also trying to solarize weeds, having covered damp ground with a sheet of plastic to avoid pesticides or pulling. Solar has its drawbacks such as overcast days, rain or timing — a solar oven won’t work at night. The learning is an adventure–nothing ventured, nothing gained.

Someday, after mastering the winds, the waves, the tides and gravity, we shall harness for God the energies of love, and then, for a second time in the history of the world, man will have discovered fire. Pierre Teilhard de Chardin