Ice slurry production control system for supercooled brine in a nylon helical coiled heat exchanger.

The formation of ice slurries from supercooled NaCl brine was studied, utilising a vertical helical coiled heat exchanger, of nylon piping. Slurry production occurred in a precise flow rate and bath temperature range. Pressure (P) and temperature measurements were implemented in a flow rate control system aimed to maintain maximum ice slurry production. A safety check set the pump flow rate to maximum if pressure or dP/dt readings increases beyond set maximum values. Ice fraction and production rate measurements were taken as a performance indicator. Evaluation of the initial results showed slurry ice fractions above 10%, but with growing unstable pressure oscillations and a decrease in ice fraction. An improved proportional based control system was implemented without the safety check. Pressure oscillation amplitudes were reduced, ice fractions and production rates were preserved or increased during the experiments.