How long can a vaccine container stay cool without electricity? Researchers at the Technological Institute of the Philippines investigated a passive container designed to maintain a vaccine compartment between 2 and 8 °C for 17 days in a constant 35 °C environment. The design combines vacuum insulation with phase change materials (PCM), which absorb heat as they melt.
The study used the FEATool Multiphysics toolbox for an independent Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) check of the container’s thermal behavior. At the 408-hour design target, the paper reports a vaccine-center temperature of 7.55 °C. The simulation also showed where heat entered the container, helping assess the role of its layered insulation and thermal storage.
The cylindrical container surrounds the vaccine compartment with three PCM layers that change phase at different temperatures. Vacuum insulation slows heat entering from the surroundings, while the PCM layers absorb incoming heat. A central PCM buffer is intended to help prevent excessive cooling near the payload. Together, these components aim to extend storage time without active refrigeration.
The researchers first developed a two-dimensional axisymmetric finite-volume model in MATLAB to simulate heat transfer and PCM melting. This model represented the container through a cross-section along its axis and included heat exchange with the surroundings through convection and radiation. It was used to explore layer dimensions and select a compact configuration. The primary model predicted a holdover time, the time within the specified temperature range, of 431.7 hours, or about 18 days.
FEATool then provided a separate numerical check of the selected design. Its reported temperature field showed a strong change in temperature across the radial layers and much smaller differences along the container’s height. The paper reports axial variation of no more than 0.8 °C. Most heat entered through the cylindrical sidewall, supporting the emphasis on insulation and PCM layers surrounding the vaccine compartment.
These results describe a simulated design under a constant ambient temperature. Physical prototype testing and qualification remain future work. The FEATool calculation provides an additional check of the predicted thermal behavior, while the full holdover prediction comes from a primary MATLAB model.
In this work, FEATool Multiphysics helped researchers examine temperature distribution and heat-flow paths in a vaccine cold chain container. For related modeling techniques, its axisymmetric modeling tutorial explains how rotational symmetry simplifies a model, and its heat-transfer example with convection and radiation demonstrates thermal boundary conditions. These resources illustrate parts of the workflow rather than the complete multi-PCM container model.
References
- Eugene E. Caniete and Nicanor Serrano, Thermodynamic Synergistic Optimization of Extended-Holdover Multi-PCM Passive Vaccine Cold Chain Containers. Preprint, 2026, doi: 10.2139/ssrn.6929341.