Operational experiences with an ice slurry cold thermal storage system using the R718 direct evaporation ice generation process.

With an increasing share of renewable energies efficient storage technologies are in high demand. Pumpable water-based ice slurry represents a thermal storage medium which has ecological as well as economical advantages due to the high specific enthalpy of fusion. A pilot installation of an integrated ice slurry generation and storage system based on ILK’s R718 centrifugal vapor compression technology was commissioned at Zwickau University of Applied Sciences in 2014. The main parameters of the plant are: 50 kW ice generation capacity; 350 kWh latent storage capacity and a discharging capacity of 100 kW. A review is made after two years of operation, focusing on plant behaviour – in general and under special conditions,energy efficiency analysis and the interaction with the complex chilled water system will be reported. Furthermore issues on current design and process limitations are discussed in order to point out needs for research and optimisation potentials from a practical perspective.