Within the scope of the DiTES4Grid project, funded by the Federal Ministry for Economic Affairs and Energy (BMWi) as part of the Energy Storage Funding Initiative, the Centre of Applied Energy Research ZAE Bayern, Bayernwerk AG and BSH Hausgeräte GmbH are analysing to what extent latent heat storage systems made of phase-change materials (PCM) might be suitable for storing cold when there is excess electricity and releasing it back into the refrigerator when there is insufficient electricity. From the researchers’ point of view, this principle can be ideally applied to cooling units, since latent heat storage systems can store large amounts of energy without incurring any significant loss.

In tests conducted as part of the project, conventional no-frost refrigerators of the highest energy efficiency class A+++ were used, simply enhanced by a container for the PCM. Part of the project involved testing various eutectic salt solutions to determine what kind of the latent heat storage system might in future be integrated into refrigerators as efficiently and economically as possible. The tests conducted so far have shown that under realistic conditions, a refrigerator could run for up to nine hours without being supplied with electricity.

Whilst the system’s feasibility has been proven, the charging process still needs to be made more efficient and the stability of the eutectic salt solutions further improved. More tests will be carried out before the project is concluded in September 2018 – among other aspects, the durability of the system is to be examined in long-term tests.