The following article was written by Ben Chapman, a first year student. It was published in the Olin College student newspaper.
Freshmen Explore Sustainable Food-Storage
On November 13, I was working Essex, VT with three other Olin Freshmen, on an exciting sustainable engineering project: a walk-in freezer that uses no energy. In July, I helped with the design and initial construction of the freezer. I have since brought the idea to Olin for some further investigation.
The freezer itself is very simple. It is a super-insulated room about 16 feet by 12 feet. Inside, the walls are lined with about 3000 two-liter soda-bottles, filled with salt water. In the winter, hatches in the ceiling are opened up and everything freezes. In the spring, the hatches are closed, and the freezer stays at about 20℉ all year long.
Earlier this semester, I told Professor Allen Downey about the project. He decided that it would make a great project option for the Modeling and Simulation class that he co-teaches for all Olin freshmen.
More than a dozen students chose to model the freezer. Some answered questions about the effects of salt concentration, local climate, or entering and exiting the freezer. Others made tools for potential freezer-builders that calculated the number of bottles necessary for a freezer of a given size. One group investigated the possibility of building a passive air-conditioner using the same technology.
The modeling project came to a close, but some students wanted to do more. Freshman Ken Berry requested that we take a trip up to Vermont to help insulate the structure and prepare it to freeze this winter. Two other classmates, Casey Monahan and Chase Kernan, also came to help.
To begin, we modified a commercial leaf-mulcher to grind up waste-Styrofoam into a loose-fill insulation that we could pack into the wall cavities. We also filled over 250 soda-bottles with water and salt. They will eventually be stacked against the walls inside the freezer.
Our last task was to install temperature data-loggers. These will let us track the freezer’s performance and see how it compares to our simulations.
Our next goal is to use the models developed at Olin to create a website for people interested in building a freezer. Our dream is that in ten years there will be hundreds of these built all around the world, providing free, zero-emissions food storage.