Improving the thermal efficiency of ice slurry production through comminution

Producing ice slurries by crushing blocks of ice and mixing them with an aqueous solution of freezing point depressant can significantly increase the coefficient of system performance, decrease production time and eliminate the negative effects of time behaviour associated with storing fine particle ice slurries. As ice is mixed with an aqueous solution, it melts or freezes, diluting or concentrating the liquid phase. Its resultant properties can be estimated from an enthalpy balance. Using the phase diagram of the NaCl + H2O system and published heat capacity curves for ice and brine, a model is constructed that predicts resultant ice slurry properties following mixing. Model predictions are confirmed by experiments where a number of ice, water and salt mixtures are produced whilst their properties are monitored. Finally, it is shown how this method can be used to give optimum salt gritting loads for the deicing of roads.