Top 20 team in the 2018 High School Utah Entrepreneur Challenge at the University of Utah. lassonde.utah.edu/hsuec

1. The SubzeO Medical Fridge

2. Problem
● Many medications, such as vaccines for seasonal flu and tetanus, must be kept at 45° F. Other medications, such
as insulin, must be kept at 75° F, otherwise they lose their effectiveness and potentially become dangerous
● Many of the temperature sensitive medications such as respiratory medications and tetanus vaccines are in
highest demand after a natural disaster,
● During natural disasters, the ‘cold chain’ is often interrupted, stopping the flow of medication when it is in the
highest demand
● Hurricane Maria, which struck Puerto Rico last September, knocked out much of the island’s power grid. While
most hospitals had backup generators, fuel shortages forced many hospitals to close or experience intermittent
power outages, which damaged many medications past the point of salvage
● Virtually all refrigeration systems require electricity
● Not only does this prove an issue for patients who need the medication, but also for the hospitals who have a
limited supply to medications
● Puerto Rico suffered especially from the insulin shortage, as the territory has the highest prevalence of diabetes in
the United states at 13%

3. Solution: A Fire Powered Fridge
● During catastrophes and natural disasters, the power grid is often destroyed or rendered unusable. Access to fuel
required to power generators can become scarce, as the delivery infrastructure is destroyed (as seen in Hurricane
Maria)
● Firewood and sunlight is still abundant after most catastrophes however, which is why both can be used as the
power source for SubzeO
● The SubzeO is a refrigerated device that is specifically tailored for storing medication after natural disasters such
as Hurricane Maria. The SubzeO can maintain a constant temperature indefinitely, powered by heat energy from
fire or the sun
● The SubzeO works by using zeolite, a hygroscopic mineral, to absorb water vapor from a water filled casing
surrounding an inner storage area. The evaporation absorbs heat, cooling the water which then chills the contents
of the the SubzeO

4. Prototype
Lid
Removable
Zeolite Pack
Internal storage
for medications
Closed reservoir
filled with water

5. Operation
● To first operate the SubzeO, the user sets the temperature which opens the valve between the water filled jacket
and zeolite. The zeolite then starts cooling the water, which in turn cools the interior.
● A small, battery powered light on top of the SubzeO will display the time left before the zeolite must be
regenerated, between 2-3 days depending on difference between inside and outside temperatures.
● Once in need of regeneration, the user swaps in the used zeolite charger for an fresh one, and then refills the water
that was absorbed by the last zeolite pack
● The zeolite packs are recharged through heating- either by being placed directly on a fire for approximately 20
minutes, placed in the solar recharge array for a number of hours, or placed in an electric recharge station
(requires a separate pack)
● During recharging, absorbed water is evaporated through the one-way valve of the zeolite pack. The structure of
the zeolite is not changed throughout this process, and can be reused indefinitely

6. Prototype Part 2
Zeolite package
detached
Airtight port for
attaching zeolite
Extra insulation
between zeolite
and cooler Airtight port for
refilling water

7. Prototype Part 3
Zeolite package
detached
Water filled jacket
without covering

8. Function and Proof of Concept
Function:
● The SubzeO works by harnessing the energy of evaporation to cool. Changing liquid water to a gas, (evaporation),
requires energy. This energy is taken from its surroundings, cooling them. This process is called evaporative
cooling, and is the reason we sweat and why swamp coolers work
● Zeolite refrigeration uses evaporative cooling, as the zeolite is hygroscopic (able to rapidly remove moisture from
air) . When humidity is removed, more water evaporates due to its vapor pressure. Eventually, an equilibrium is
reached between the evaporation rate of the water and absorption rate of the zeolite.
Proof of Concept:
● Coolkegs, a German company, uses zeolite and water to create self cooling beer kegs. The process, however,
requires the keg to be sent back to the factory for regeneration between every use.
● Researchers at Zeo-Tech GmbH in Unterschleisshiem, Germany, has created electric powered mini fridges using
the technology, but they have yet to reach market

9. Customer
Primary Markets include:
● Hospitals and clinics in disaster prone areas, as a way to ensure that temperature sensitive
medication remains functional in the case of power outages and emergencies
● Developing areas that do not have reliable access to a ‘cold chain’ for medication, due to unreliable
power, road, and fuel access
● FEMA, The Red Cross, and other disaster response and relief organizations
Potential Markets Include:
● Emergency preppers
● Outdoor recreationalists
● Semi permanent camps set up during expeditions and the military

10. Comparison to Existing Products
● Existing medical refrigerators require a constant supply of electricity to keep the medication at the
correct temperature, and even a brief lapse can ruin the medication.
● There are expensive and nonmobil refrigerators that have a backup battery which typically lasts
four hours. In a disaster scenario where a hospital is running off of generators, using limited fuel
supplies to recharge the battery of a fridge is not top priority.
● The Zeer Pot, a homemade evaporation cooling refrigerator, doesn’t work in high humidity, doesn’t
reach low enough temperatures, and isn’t mobile.
● Filling a cooler with ice or dry ice is only a temporary measure, and provides challenges to
controlling the internal temperature.
● Absorption refrigerators are not mobile and have many movable parts that require upkeep.
● SubzeO is the only product that can reliably keep medications cold for an extended period of time
without access to electricity.

11. Impact
● The SubzeO will help future victims of natural disasters who rely on medication that is temperature
sensitive
● The SubzeO also helps hospitals in similar scenarios, by allowing them to focus limited generator
fuel on life saving systems instead of refrigeration. Additionally, it will prevent the spoiling of
medication that would otherwise require reordering
● The SubzeO could help extend the range of medication cold chains, allowing more remote areas to
have access to temperature sensitive, and potentially life saving, medications.

12. Sources
Zeolite is hydroscopic: https://books.google.com/books?id=4kvzBRUuGDkC&pg=PA17
Heat of Evaporation:
https://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Thermodynamics/Energies_and_Potentials/Enthal
py/Heat_of_Vaporization
Zeolite German minifridges:
http://www.bine.info/fileadmin/content/Publikationen/Englische_Infos/projekt_1610_engl_internetx.pdf
Puerto Ricos Slow Moving Medical Disaster: https://www.wired.com/story/puerto-ricos-slow-motion-medical-disaster/
Lack of Hospital Generator Fuel in PR: https://www.npr.org/2017/09/28/554182929/in-puerto-rico-relying-on-luck-and-
enough-gas-to-get-medical-care
Costs of Broken Cold Chain: http://csafeglobal.com/the-cost-of-a-broken-vaccine-cold-chain-part-two-financial-cost-1
http://csafeglobal.com/the-cost-of-a-broken-vaccine-cold-chain-part-one-human-cost/
PR deaths continue after the storm: http://www.latimes.com/nation/la-na-puerto-rico-death-toll-20180228-story.html
Remote Locations Aren’t accsessible by cold chain: http://knowledge.wharton.upenn.edu/article/vaccines-cheese-
caves-energizing-cold-chain/
Healthcare supply chain and disaster: https://ac.els-cdn.com/S2351978915011233/1-s2.0-S2351978915011233-
main.pdf?_tid=d43eafc2-2f5f-4311-9c7b-c5d74b993ca8&acdnat=1519943665_484693e4e81142dc202f2432d0f05d68