Increasing the Energy Efficiency of Icemaking by Continuous Solidification and Hydraulic Harvesting
Energy constitutes the largest portion of the variable cost of icemaking. The removal of ice from the freezing surfaces of an icemaker can consume as much as a quarter of the total energy input. An icemaker has been built and tested that employs mechanical force to remove the ice. The device consists of a finned aluminum circular tube enclosed in a refrigerating jacket. The lower end of the tube is connected to a high pressure pump while the upper end remains open. Water introduced into the lower end by the pump at a metered rate freezes into a solid ice cylinder. The hydrostatic pressure developed by the pump overcomes the adhesive shear strength of the ice on the cylinder walls forcing the ice out the open upper end. The ratio of the power required to harvest an increment of ice to the power required to freeze an increment was found to be proportional to the process temperature and ranged from 3.5 to 1.5% over the temperature range tested. The energy savings appear to be significant.