Due to globalization and post-pandemic developments, the shipping industry's search for energy-efficient containers in the cold chain sector has increased significantly. In this scenario, the vacuum insulation panel (VIP), a thermal superinsulation, shows significant potential to be used in the construction of highly energy-efficient shipping containers. However, a concern is a lack of information about the long-term performance of VIPs due to truck vibrations during transit. This paper investigates this gap by presenting results from a laboratory test program involving unaged and aged VIP specimens (300 mm x 300 mm x 25 mm) with two types of core materials, fumed silica and fiberglass. The VIP specimens were subjected to random vibrations, reflecting actual in-service vibrations of a truck. Vibration tests were conducted using a Long Stroke Vibration Exciter (ball bearing type) for the low-frequency range following the procedure outlined in the ASTM Standards D4169 and D4827. Aged specimens underwent ’heat’ (70 ±1°C and 5 ±3 % RH) aging in an oven and ‘heat & vapour’ (70 ±1°C and 95 ±3 % RH) aging in a specialized environment chamber for up to 120 days before going through random vibration tests. The change of thermal conductivity of each specimen was tracked during the random vibration test at regular intervals using a heat-flow-meter, following the procedure in the ASTM Standard C518. The results from the thermal conductivity test indicate that, in general, fumed silica VIPs have a lower degradation rate than fiberglass VIPs when subjected to simulated random vibration tests.

The findings of this study will have meaningful implications for the use of VIPs in energy-efficient refrigerated shipping containers. By identifying the impact of truck vibrations on the performance of VIPs, researchers and engineers can develop more effective methods to mitigate these effects and improve the overall integrity of the VIP-insulated highly energy-efficient refrigerated shipping containers. Overall, this study provides insights into challenges and opportunities associated with using VIPs in the cold chain industry and opens new avenues for further research and development in this field.