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| Construction of our Solar Dehydrator (Nick Ho) |
This past week, our group has continued working diligently on our solar dehydrator and solar oven. With our plans finalized, we have completed the construction of the two machines. We conducted research on what types of food we would be able to dehydrate based on our northeastern climate. This site has guided us with valuable solar cooking tips which have been valuable in our tests.
Solar Dehydrator:
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| Solar Dehydrator at Work (Nick Ho) |
The dehydrator consists of two parts, each based on other designs (here and here). The first part of our dehydrator is a pizza box which houses the food we are trying to dehydrate. The other part of the dehydrator is a cardboard box. These two parts are designed to simulate phases of convection. Our group lined the inside of the cardboard box with aluminum cans and spray painted the inside black to act as a insulator of solar heat. Additionally, we glued a piece of glass to the roof of the box to create a greenhouse effect. We also included holes in the bottom of the box so that cold air could enter the dehydrator. On the other side, we plugged in a tube through which the warmed air could travel to the pizza box. In the pizza box there is a mesh platform on which food can rest to be dehydrated. The pizza box, like the first part of the dehydrator, has a piece of glass glued to the roof of the lid. This design will be able to simulate two processes of convection as well as apply greenhouse principles. Thus far, we have noticed both parts working in conjuncture being incredibly effective. We have also applying similar concepts towards our solar cooker, which we tested after our dehydrator.
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| Visual Representation of a Convection Current (emaze.com) |
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| Weighing Bananas (Nick Ho) |
The first step in testing our constructed dehydrator was slicing out and weighing banana slices. We weighed them out at 40.21 grams. We then placed it in the sun, and created a schedule for which we could check in on the dehydrator and make sure it was functioning correctly. After a few check-ins, I discovered the lid of the dehydrator's pizza box lifted open, and our dehydrated banana slices strewn around the ground. That being said, our dehydrator was very successful at completing its task. Our second test of the dehydrator found equal, if not more success. Our maximum temperature recorded was 130 degrees Fahrenheit.
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| Construction (Tate Singleton) |
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| Construction (Tate Singleton) |
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| Dehydrated Bananas (Nick Ho) |
Solar Oven:
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| Solar Dehydrator at Work (Jay Yun) |
Our oven design is quite simple, it uses an aluminum pan, an aluminum mirror and glass to collect concentrated UV radiation waves. These waves from the sun are small enough to puncture cell membranes. The UV rays puncturing the material inside the oven release energy within the membranes which is known as electromagnetic radiation which mutates the food and cooks it. We used aluminum as an insulator because of its ability to reflect UV rays, the primary method of heating back into the system and its low specific heat. We also used glass and caulking to seal the system so energy was not lost through the method of conduction and convection with colder air. The glass is also helpful to reflect UV rays back into the system that causes a greenhouse effect within the system.
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| Solar Dehydrator at Work (Jay Yun) |
We tested our solar oven twice. The first time we tested it, we realized some fundamental flaws in the design, namely that the insulation was barely enough to hold the amount of heat we needed to cook a grilled cheese sandwich. Our sandwich was cooked, but not nearly as cooked as we wanted it to be. So we tweaked our design and added layers of foam inside the oven itself to act as insulation. Additionally, we opened the sandwich so that the cheese would melt quicker and easier. Unfortunately, the weather was not on our side. We made the best of an unfortunate situation, figuring out when the sun would be out for the longest period of time. In the end, our oven reached temperatures as high as 170 degrees Fahrenheit.
We realized, perhaps too late, one of the suggestions outlined on one of our sources. "Most food, with the exception of cookies and open-faced sandwiches, are cooked in containers with the lids on. Perhaps in the future, if we're given more freedom to test our apparatuses, we could modify our design yet again and see if the results are affected.
Personal Reflections (written May 9, 2016):
This past week, we were given the task of finishing our solar dehydrator. Unfortunately, I was not able to go to class due to a urgent doctors appointment. My group was close to finishing but not quite. There we still some minor details that we needed to complete. By the end of class, our group became very close to finishing our dehydrator. We have to fix one thing and we will be ready for testing it. I am enthused with our teamwork and camaraderie. I have faith in our group that we will be successful in this project. We start our solar oven tomorrow and I'm looking forward to it!
-Tate Singleton '17
We are about to finish building our solar dehydrator. It seems like other teams are done with their dehydrator which worries me. The reason we are behind is because we have two parts within our dehydrator. We have a part that generates warm air and an actual dehydrator made out of a pizza box. The other reason that we are behind is we didn’t have Nick and Tate during last class. Julian and I got a lot done but I feel like we could have done much more when we had all of our members. Even though we are taking longer to build our dehydrator, I am confident that ours will work really well because we have two mechanisms that dry food. First is the direct heat energy that our pizza box receives. The second is hot air floating in that is generated from the box with aluminum cans. We will start testing our dehydrator starting tomorrow. I am also excited to move on to our solar oven. I feel like it will be a bigger challenge but with my teammates, there is no doubt we will make a great one.
-Jay Yun '16
Right now, we're behind other groups. Everyone has begun testing of their dehydrators, while we are struggling to complete the construction of ours (we still need to figure out a way in which we can hold the pizza box elevated, as well as gluing the tube to the bottom of the pizza box. However, I'm confident that we'll soon be finished building our dehydrator, and we can begin testing. I'm excited to figure out how our design could use improvement. The next step after that is building and testing our solar oven.
- Nick Ho '16
Now that I am more comfortable with the concepts of our solar instruments, I look forward to being a more useful group member. I am still working hard within the group to accomplish the labor of the projects and well as continuing my research towards being able to explain the concepts of environmental sciences at work from a different perspective. It will be challenging to learn these concepts alone, as well as at an AP course level. I welcome the challenge and look forward to presentation as well as building a strong solar oven.
- Julian Roche '16
