Solar Fridge

User Need

Design Requirement

Design Specification

Vaccines viability is maintained so there is no waste

Maintain vaccine viability during power shut-off

Uniform 2°C and 8°C [1] temperature range for 72+ hour holdover time [2] at maximal 43°C ambient temperature

Fridge must be affordable for all clinics

Cost effectiveness

Manufacturing + shipping costs <$900

Nurses/Doctors need to easily see internal temperatures of fridge

Provide feedback and alerts

Indicator for temperature excursions outside 2°C and 8°C

Displays present, max, min temperatures

Stores past temperatures with 1 measurement/30 min [3]

Follow safe storage conditions for vaccine viability

Storability and organization

Vaccines stores 2-3 inches for unit boundaries [3]

Storage of 50+ vaccines

Separation for 9+ vaccine types [4]

Project History

The origins of Solar Fridge began as a Senior design project in 2008 and transitioned into an interdisciplinary team within M-HEAL a few years later. There have been several iterations of the prototype since the project’s creation. Ultimately, the team has focused on creating a solar-powered fridge, utilizing solar panels and a rechargeable battery.

By 2023, our two engineering subteams—Temperature Control and Electrical—created a combined low-fidelity prototype based on extensive brainstorming and material research.  The Temperature Control subteam focused on constructing a highly insulated and portable cooler while the Electrical subteam made a cooling system using a Peltier Device and PID controller. Each of these subsystems was tested individually and adjusted according to the results.

During this time, our Business subteam developed a new website platform for Solar Fridge and guided the team to the Michigan Business Challenge Finals, a competition for new business proposals.

From Fall 2023 to the present, the engineering subteams have worked on creating a new high-fidelity prototype based on the testing results of our Winter 2023 low-fidelity prototype. The Temperature Control subteam purchased a larger, more transportable cooler and integrated upgraded insulation materials. The Electrical subteam converted the main power source of the cooler to solar panels. We continue to make design upgrades, test new changes, and implement feedback from our trip to Rincon Claro in May 2024. Through this time, the Business subteam led us through the semifinals of the Rice360 global health design competition, raised travel funds, and planned our international trip to the Dominican Republic for testing of our high-fidelity prototype.

team advisor

Dr. Solomon Adera is a professor in the Mechanical Engineering Department. He earned his Ph.D. in Mechanical Engineering from MIT and was a postdoctoral researcher at Harvard prior to his position at UMich. His research interests include heat and mass transfer phenomena, and he teaches the undergraduate mechanical engineering heat transfer course. He has shown a strong commitment to serving disadvantaged communities throughout his career, and he has served as Solar Fridge's team advisor since 2023.