Fraunhofer ISE and BASF nominated for the German Future Prize (Deutscher Zukunftspreis) 2009

The basis for the innovative product developed by the three research scientists Prof. Dr. Volker Wittwer of Fraunhofer ISE, Dr. Ekkehard Jahns of BASF SE and Dr.-Ing. Peter Schossig of Fraunhofer ISE are so called phase change materials (PCM). The reason why these materials are so effective is due to a physical effect: During the transition from solid to liquid, PCMs absorb vast amounts of energy from their environment without heating up. This happens at a defined temperature range between 21° to 26°C. The absorbed heat is “hidden” inside the PCM or latent heat storage material (from Latin latens = hidden) and only released when there is a drop in the ambient temperature. Hence, PCM ensure that the temperature in living rooms, schools or offices never rises above or falls below comfortable levels in summer or winter, respectively. At best, it is even possible to do without air cooling units altogether during summer.

In order to utilize latent heat storage materials as a component for building materials, Volker Wittwer and Peter Schossig of Fraunhofer ISA came up with a clever idea. It consists of packing single drops of the storage material into tiny casings – experts refer to it as microencapsulation. Ekkehard Jahns of BASF developed the required technology and discovered ultrapure paraffin wax as a suitable latent heat storage material. The wax drops are encapsulated in small hollow spheres made of acrylic glass with a diameter of only a few micrometers. These microcapsules can be easily integrated into building materials such as mortar, plaster, and wood and are very robust: construction materials with Micronal® PCM can be processed as usual. Even drilling holes or driving in nails is not a problem. Due to their large overall surface area, the numerous storage microcapsules can swiftly exchange energy with their environment. Through the night-time release of the excessive heat that they absorb during the day, they reduce temperature fluctuations and create a balanced and comfortable indoor climate.

The research team of BASF and Fraunhofer ISE began developing latent heat storage materials for buildings in 1999. The PCM microcapsules of BASF have been used in various construction projects all over Europe and with great interest by builders and architects worldwide. This is due to the fact that construction materials containing Micronal® PCM can, if they are an integrated part of the energy concept of buildings, replace traditional cooling systems completely or in part, without electricity and maintenance costs. In addition, their use leads to a sustainable reduction in carbon emissions.