Cuce, Pinar MertGuclu, TamerCuce, Erdem2026-02-282026-02-2820251388-61501588-2926https://doi.org/10.1007/s10973-025-14361-yhttps://hdl.handle.net/20.500.12403/5935This study investigates the application of a CuO-Al2O3/water hybrid nanofluid as a coolant in thermoelectric vaccine refrigerators, aiming to enhance heat dissipation from the Peltier module's hot side. A 35-L cooling cabinet was utilised, and experimental comparisons were made using water and a 2% CuO-Al2O3/water hybrid nanofluid. Results show that the vaccine cabinet reaches the target temperature of 4 degrees C in 990 s with nanofluid, compared to 1200 s with water. The system's energy consumption was reduced by 18.3%, and carbon emissions decreased by 12.3% over a 15-year lifespan, highlighting its environmental benefits. Despite similar coefficients of performance (COP), the nanofluid system demonstrates enhanced efficiency, shorter cooling times, and long-term sustainability advantages. These findings support the adoption of hybrid nanofluids in thermoelectric cooling applications for energy-efficient and environmentally friendly refrigeration systems.eninfo:eu-repo/semantics/openAccessThermoelectric coolingCuO-Al2O3 hybrid nanofluidVaccine refrigerationLife cycle cost analysis (LCCA)Carbon footprint reductionArticle15013105951060810.1007/s10973-025-14361-y2-s2.0-105007244990Q1WOS:001501658100001Q2