Development of a new methodology for validating thermal storage media: Application to phase change materials

Long-term stability and long-term performance of thermal storage media are a key issue that should be thoroughly analysed when developing storage systems. However, no testing protocol or guideline exists up to now for validating storage media, so that authors apply their own criteria, not only for designing testing procedures but also for predicting the material behaviour under long-term operation. This paper aims to cover this gap by proposing a methodology for validating thermal storage media; in particular, phase change materials (PCMs). This methodology consists of different stages that include PCM characterization, preliminary assessment tests, and accelerated life testing. For designing the accelerated life tests, lifetime relationship models have to be obtained in order to predict PCM long-term behaviour under service conditions from shorter tests performed under stress conditions. The approach followed in this methodology will be valid for materials to be used as sensible or thermochemical storage media, too.