Compact and Flexible Thermal Storage (IMAGE) Fraunhofer-Gesellschaft Caption These zeolite pellets can bind steam within their pores, generating heat. Credit Fraunhofer IGB Usage Restrictions The picture may be used for editorial purposes only. It is protected by copyright. The use is free of charge if the reference is mentioned. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.