Reducing Humidity in Solar Vaccine Refrigerators with Reusable Silica Gel

For their senior design project, Cal Poly Mechanical Engineering students Alex Emme, Brandon Natividad, and Andrea Hernandez worked with SunDanzer to address persistent high humidity inside solar-powered vaccine refrigerators. Although these refrigerators must operate between 2–8°C, internal relative humidity can reach 80–90%, contributing to condensation, fogging, icing, and potential damage to vaccine packaging and labels. The team compared thermoelectric condensation with a compact, regenerable silica gel cartridge intended for low-cost, low-energy deployment.