Slurry-Store: Experimental and numerical investigations of ice slurry storages

Ice slurry generation technology with the supercooling method consists of cooling water below its melting point
in a supercooling heat exchanger, called supercooler, therefore retaining this water is in a thermodynamically
metastable liquid state. Downstream from the supercooler, the supercooled water flows through a flow-based
crystallizer where the supercooling potential is released by forming a water/ice flow mixture. In this process,
the latent energy released by crystallization equals the sensible supercooling potential defining the percentage
of the water that is converted into ice particles when forming the ice slurry flow. This latent energy is released
in order to restore the thermodynamic equilibrium corresponding in equal internal energy to the metastable
state from which it is formed. The greater the extent of supercooling achieved, the greater the quantity of
liquid water that is converted into solid ice.
At the SPF Institute for Solar Technology we have been working with solar-ice systems for more than a decade.
The solar-ice concept is a solar thermally assisted heat pump system that includes an ice storage component
capable of bridging periods during which solar input is insufficient by itself to supply thermal energy to the
heat pump’s evaporator. The ice storage acts as a low-temperature seasonal storage to shift solar heat from
summer to winter, while also being partially charged/discharged on a daily basis in winter to cover shorter
periods with insufficient solar irradiation, e.g. nights or cloudy weeks. The ability to continuously charge and
discharge, the use of water as both the heat transfer and heat storage medium, and water’s large latent heat of
fusion, collectively contribute to a levelized cost of storage outperforming most conventional, thermal energy
storage technologies.