Single-stage metal hydride-based heat storage system

摘要

? 2023 Elsevier LtdThe effective use of renewable energy sources (RES) becomes increasingly important, and energy storage systems are needed to ensure their stable operation. Metal hydrides (MH) can be used both for hydrogen storage and for thermal energy storage (TES). We present experimental results of heat, mass transfer and dynamic processes in a single-stage MH-based TES system based on a 5 kg La Ni4.8Mn0.3Fe0.1 metal hydride reactor. Stable cyclic operation in the temperature range 20–90 °C is demonstrated with volumetric energy storage density of 208 MJ/m3 and peak thermal power of 1.05 kW. The systems performance is analyzed regarding the energy and exergy efficiencies. The main bottlenecks include the connected thermal mass of the reactor and the necessity to use lightweight and efficient heat exchanger. In addition, a liquid flow rate in the heat exchanger should be kept low enough to decrease the difference between temperatures of the MH bed and coolant. Optimized low-temperature metal hydride TES systems can be used in climatic-oriented applications, such as MH starters for cold weather or “keep warm” systems.