Thermal energy-storage system using phase-change materials

Scientists at the U.S. Department of Energy’s Argonne National Laboratory (Lemont, Ill.; www.anl.gov) have developed a thermal energy-storage system for industrial processes that can capture and store typically wasted heat for later use. Originally conceived as a way to store surplus heat from concentrated solar power installations, the system is being refined for other applications, including storing heat from industrial combustion processes, solar-powered desalination plants, combined heat and power (CHP) facilities and heavy-duty trucks. The device stores and releases latent heat using specific types of molten salts as phase-change materials that melt when heat is captured from a process, then solidify when the heat is released for later use. In the development of the storage system, the Argonne team, led by senior materials scientist Dileep Singh, overcame a key limitation of molten salts. While molten salts can be effective as phase-change materials for retaining heat, they are typically poor thermal conductors, “so it takes too long for them to absorb and release energy,” the team says. To overcome this, the researchers devised a proprietary method to integrate the phase-change materials with another high-thermal-conductivity…