Sorry to neglect this blog for so long. Homeschooling comes first, then projects, then blogging. I have quite a backlog of resources I will post as soon have more time.
For science fair, my son decided his project will be to improve upon my trash can solar oven. The current title is “Solar Cooking in Difficult Weather” because the goal is to cook as well in the winter as we have done in the summer. The trash can cooker was built without reflectors due to high winds we experience regularly. The new oven be compared side-by-side with the trash can one. If you have read my notes on that at the beginning of this blog, then you know there are plenty of things that can be done to improve the first solar oven. The point of that oven was to put as little effort into it as possible and see how it worked. The result was that it worked for three years without fail. It worked in the winter, but not as well. We think the metal from the trash can allowed heat to escape via conduction and long shadows were the biggest problems. This winter we will compare to find out. He is also considering using reflectors for the first hour of cooking since it seems to be far less windy at 11 am-noon than it is later in the day. The first part of cooking is just getting food up to a cooking temperature. If the clouds roll in after the food has reached cooking temperature, it will continue to cook on stored heat for a little while. This is where he will be doing a lot of observation and making design adjustments.
On August 23, the trash can solar oven had its first major accident. High winds blew its top off. I don’t mean the glass. I switched the lid with the trash can’s original lid when I saw the high winds. The following morning, I discovered the lid was blown off and the interior of the oven was soaked in rain water.
By September 23, we missed solar cooked foods intensely. This time my son did all the work while I walked him through what was needed and why. By myself it would have taken less than an hour to cut cardboard and reassemble the oven. Because I was teaching it took much longer.
Today we are using fence wood we got for free off of Craig’s List to make my son’s solar oven for his science fair project. Some of the slats are 5-3/4″ wide and some are 11-3/4″. The oven’s outside dimensions will be 25″ square with a slope starting at 11-3/4″ down to 53/4″. The lid will be glass from a storm door. It’s outside dimensions, including an aluminum frame, are 27″ by 28″.