Experimental investigation of different materials for use in ice slurry generation

Helical coiled heat exchangers (HCHX) are utilised to make ice slurry hygienically. The effects of four material coils was investigated: nylon, polytetrafluoroethylene (PTFE), silicon rubber and aluminium. Operation regions and ice production rate results for the materials were compared to nylon. PTFE production rates were highest at warmer refrigeration temperatures (up to -9.5 ∘ C) and a wider stable operation region at high flow rate. Silicone rubber created a wide stable operation region and used the warmest refrigeration temperatures (up to -8 ∘ C); however, ice fraction and production rate were lowest. No stable ice slurry production was achieved with aluminium. PTFE produced the lowest nucleation temperature due to its hydrophobic surface in further nucleation temperature tests; aluminium had the warmest nucleation temperatures. The duration of experiments was extended to 6000 s by (1) recirculating fluid (2) a control system for flow rate to prevent blockages and maximise ice production. PTFE and nylon produced similar amounts of ice, 1 kg and 0.96 kg respectively.