Abstract
One of the main advantages of ice slurry as secondary refrigerant is the possibility of cold storage, which enables load shifting and peak shaving. During cold storage, ice crystals are subject to mechanisms as attrition, agglomeration and Ostwald ripening causing changes in the crystal size distribution, which are of great importance for ice slurry systems since they influence other parameters such as pressure drop and heat transfer characteristics. Storage experiments with ice crystals in aqueous solutions of sodium chloride, ethylene glycol, ethanol and propylene glycol show that Ostwald ripening is the most important mechanism inducing an increase in average crystal size. The ripening rate strongly decreases as the solute concentration increases and the type of solute and the mixing regime also play an important role. The different ripening rates are caused by the fact that crystal growth and dissolution by means of Ostwald ripening are mainly limited by surface integration kinetics at low concentrations and by mass transfer at high solute concentrations.