8.28.10 pancakes at the farmers market

I have decided to try and network (and hopefully find an engineering job) by showing people the lens cooker. I feel that the dish cooker is much to dangerous at this point because a person could be blinded just by looking directly at it. I was considering heating syrup up with the cooker but it would boil if I left it on to long. I got up at 5:15 am and started making a bunch of pancake batter. I found out that we did not have any baking powder or baking soda left so since I was going to be running to the store anyway I decided to just buy organic just add water pancake mix.(probably better this way since I did not have to deal with refrigeration) I started getting attention right away. Hundreds probably at least looked at me. I probably talked with 60-70 people just in the three hours that I was there. I only had one guy laugh at the cooker but to be fair when he was looking at the cooker the bamboo stick I use to control where the focal point hits the pan snapped at the same time that the lens fell down when a gust of wind came up.(note to self get a stronger stick) Lots of people just wanted to look(this is a good thing) and most were encouraging saying things like "way to go" and "good for you" I had four people come up and ask to buy a lens cooker. I gave away several pancakes but I ate almost as many as I gave away.
I think I will go to the farmers market next week, but this time I will bring plates.

8.27.10 Solar pancakes

Today for breakfast(it was going on lunch actually) we had solar pancakes. I started with a sharp focal point and got the pan up to 475 in the middle. It works much better with the focal point spread out. I cooked enough for everyone but it was a slow process. It took 5-8 minutes per cake. The last one did not turn out because I caught the shade of a tree. I boiled water for tea on my dish cooker and Sean cooked toast on the dish. He burned a couple of pieces before he decided to hold the toast slightly closer to the dish than at the focal point.

8.26.10 Solar Bratwurst

Today my dad gave me a stainless steel mess kit. He painted it black on both sides and then we put a little water in it with some brats, closed the lid(not locked) and within two minutes we could hear bubbling and within five we had the lid popping up and shooting steam out of the side. We let them cook for another couple of minutes just to be safe and then had boiling hot bratwurst for lunch.

8.25.10 Solar Eggs

This week I am at the lake visiting my cousins. I brought the dish and the lens cookers with me in the van. This morning I was getting the temp up on the cast iron pan and someone suggested that we cook eggs. We scrambled up several eggs and once that pan hit 320 degrees we dumped them in. They cooked well. They tasted no different than eggs cooked on a stove. For lunch we had solar cooked hot dogs. We cooked them directly with the lens but we had to much of the focal point on the dogs. Let me tell you that it did not take long before one of them turned black.

8.22.10

I got my pan up to 297 degrees F in about 80% sunlight(there is a lot of shade on the balcony) It took about a half hour to reach that temp but I am confident that if I am cooking in full sunlight that I will be able to cook pancakes.

What I have tried

So I have wanted to build a solar cooker for a long time because stoves take a lot of energy and I like to be outside and keep the heat outside when it is hot. To further reduce my carbon footprint I decided that I wanted to use recycled components. So I started collecting mirrors to use as reflectors but unfortunately when I moved I had to get rid of them. I decided to see what others had done accomplish the same thing. I found some youtube videos where people were using satellite dishes to cook food. Fortunately these things are not hard to find. People get rid of them all the time because the satellite companies do not even take them off the building or recycle them at all. So I got a hold of one and I used a spray on adhesive to stick some aluminum foil on just to see what it could do. It got water warm and I was able to successfully cook some hotdogs. It took 45 minutes and the pan I used was so small(because of the small focal point) that the end of the hotdogs stuck out on one side. The hotdogs were sort of sunburned on the outside which I found to be rather interesting and pleasant(it reminded me of campfire roasted but cleaner) I decided that I needed something shinyer. I found a space blanket that I used the same spray on adhesive to stick onto the surface. Now it can do something I can heat water up to close to 170 degrees F The problems with it are that if left out in the rain, some of the shine comes off and bubbles up and the Mylar just is not a perfect surface(or reflector because I just noticed that some light energy passes right through it). I have since purchased some very shiny vinyl sticker. At this point if I use it, it will not be made of 100% recycled material so I am not sure if I want to stick it on(I am still deciding). I also found broken mirror that I could break into pieces and glue onto the face. I tried a sewing machine table for use with the dish because it is light, sturdy, and has a nice hole already through the middle but since the vertical height is not adjustable it ended up being useless. Plus the thing is made out of wood so I think if I use it it will just be asking for a solar bonfire. I got a thermal cooler that was broken out of the garbage and I painted it black(paint 5$) I covered the outside with Mylar and put a thermometer inside of it. I know I will need to cover the inside as well and since the hole in the side is only 2. inches across, I will need something to funnel the light into it. I am keeping my eye out for a stove burner plate or something else conical and shiny.

Next I found a projection tv in the trash and I am using the linear Fresnel lens from the screen to heat up pans and a black stainless steel water bottle.(ok I purchased this for $2.50)the projection tv also came with a mirror which comes in handy for reflecting the light. It takes about a half hour to boil 2 and a half cups of water. It takes 10 minutes to cook a hotdog and the first time I tried this it scared me because hotdogs pop when heated that quickly. The hot dogs were not as "sunburned" on the outside because I did not have to cook them for so long but they still had a nice thin crust(yum) I think that I can improve these time by building a proper frame for the lens. I also want to try to add additional reflectors around the front of the lens to increase the power. I picked up a camp tripod that is all shiny at the farm store (I am getting farther away from the 100% recycled thing) for 15$ but for the time it would take me to build a working tripod that is as good as this one I think that it is worth it because the sun moves so much I have to adjust the height of the cooking surface(especially earlier or later in the day) So far I have heated up leftovers quite successfully and I am pretty sure that it will cook bacon(although it will take longer then on a standard stove or over a fire)

I picked up a papasan chair because of the nice parabolic shape. Since it is so wide and deep it has a shallow focal point. My theory is that since the opening is such a large area, I will be able to capture more of the suns energy. My plan is to cover the inside with a couple of layers of mylar(hopefully it will reflect even more light that way and then set a shiny cook rack in the middle with a black pan. I think that it will get very hot.(hoping for 300 degrees F +)

I have had to purchase other equipment for this project: welding goggles(10$)(a must if you don't want to be blind) I am using a #9 lens. An infrared thermometer(25$) (I got this a while ago but it has been packed up during the course of the move, I just got it back so I am really excited about it)

So far I have learned that in solar cooking, put the light as low as you can on the object to be heated up so that the heat goes up into what you are cooking, black heats up quick, shiny heats up very little. The less steps for the light to escape the better, any reflection or thing that the light has to pass through introduces loss. The more light, the more energy.