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Report overview
The report was signed by Cynthia, Brittany, Elise, Josh, and Graham Gipson; their team website is here and has extensive documentation.

  • four nested styrofoam cups were covered in various layers of bubble tape, more sytrofoam, and insulative tape were filled with an ammonium-nitrate, water mixture to create a container that remained below 10degC for 10hrs at a cost of $2.
  • a good deal of heat-transfer modeling work was also listed
  • compiles other potential endothermic reactions on page six of the final report
  • did some thinking about zeer pots
  • mentioned the GreenBox, a product made by Entropy Solutions, that can maintain a temperature from -20degC to 50degC for two to four days. The customer specifies their target temperature and ES customizes an insulation layer that will correspond to that temperature. All the materials are supposed to be eco-friendly, hence the "Green." The product is designed for shipping needs.

Comments
There was a passing comment in the paper about ammonium-nitrate being readily available but this was not expanded further. There's also no indication about the lifetime of these devices. I would presume they're one-time use; this isn't too much of a problem if they're so cheap though. There's a noticeable lack of information on the amounts of reagent used in the tests.

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the final design with and without the temperature probe

UC San Diego team

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Report overview
The report was compiled by Ayaa Maggay, Kathryn Olson, Bindi Patel, and Aakash Datt.

  • the device consists of two chambers separated by an aqueous chemical solution of sodium acetate trihydrate
    • claim that this device may be reused once water evaporates; this needs verification
  • some thermo calculations indicate they will add nearly 500g of reagent ($30) to keep the box cold for 12hrs in 38degC ambient temperature
  • 6mL of water would need to be added to the system every 20 minutes in their worst case scenario
  • the device would be heavily insulated ($20 worth of sytrofoam blocks for each box)
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