For industrial processes that require the use of steam, such as those in the food industry, latent thermal energy storage systems represent a promising option for increasing flexibility in response to fluctuations in renewable energy supply.

A recent study, carried out by a group of German researchers (Dietz et al., 2026), lays the foundations for the quantitative analysis of control strategies for steam generators operating using phase-change materials.

The tests were carried out on a self-built, one-kilowatt single-tube test rig, equipped with extensive measurement instrumentation and precise fluid control, using water/steam as the heat transfer fluid and PLUSICE A133 as the phase-change material.

The results highlight the strong correlation between the mass flow rate of the heat transfer fluid and the storage power. It was also observed that a reduction in flow rate significantly increases storage capacity during both the charging and discharge phases. Validation of a numerical model for storage design shows that the peak power during charging can be predicted accurately with deviations of <3%. Finally, with sufficiently long charging processes, even the transient power profiles and the outlet temperatures of the heat transfer fluid can be reliably used for storage tank design.

Bibliography: L. Dietz et al., Journal of Energy Storage, 144, 119691