Monday, February 25, 2013
There's nothing like a sunny winter day for generating solar electric power. By late February the days are a bit longer. Snow still covers the ground and is amazingly reflective. It's like giant mirrors are reflecting the sunlight onto my solar electric panels.
It's a bit counter intuitive, but solar electric panels are more efficient in cold weather. Hot panels are subjected to something called “electron scattering.” No, I don't understand all the science behind it. That doesn't mean I can't notice the effect.
Of course, solar thermal panels, like those that heat water, are much more effective in warm weather.
Have you ever heard about the condition called snow blindness? It's no joke. Good sunglasses can be more important in winter than in summer. That reflective quality of snow that's so useful on the solar panels can fry your eyeballs. It's not a pleasant experience. In the summer a wide brimmed hat can stop much of the sun. Snow reflects so much sunlight that a hat isn't going to save you.
The Inuit used a type of goggle to prevent snow blindness. It's basically a slit cut in bone, ivory, or wood, to reduce the amount of light reaching the eye. A person in a survival situation could easily construction something similar in an emergency situation. Sure beats being blind.
The sun is welcome on a winter day, but its power has to be respected.