An optimization of a pre-cooling system for batch processes: A case study of the tubular ice production process

Abstract

Mathematical models for predicting the thermal behavior of feed water precooling systems for tubular ice makers were developed. A commercial water chiller and plate type heat exchanger were used as the cooling source and heat exchanging device. The simulation results suggest that the system, in which the feed water is circulated through the heat exchanger, provides a higher effectiveness (ε) with a lower heat capacity rate ratio of the feed water to the chilled water (wr) for a certain number of transfer units (NTU). In the range of the ice maker capacities popularly used, at a NTU of unity, the optimum heat capacity rate ratio of the feed water to the chilled water (wr) could be estimated to be 0.48. The water chillers would operate in the range of their minimum specific power consumptions when the feed water temperature was higher than 11 °C. The system has the potential to reduce the energy consumption about 6.7–11.6%. In addition, it can improve the productivity. The system was tested with a conventional ice maker. The energy consumption can be reduced as predicted by the model. The results could be also applied to a precooling or preheating of any production process.