Theoretical model of a thin-film vacuum freezing ice production (VFIP) method

A new vacuum freezing ice production (VFIP) method based on the solid-liqui d-vapor multiple phase transformation and the latent-heat coupling mechanis m is introduced in the present study. Coupled heat and mass flux equations based on irreversible thermodynamics have been applied to depict the ice gr owing phenomenon under vacuum, and to derive an equation for its growth rat e. Ice growth rates of the VFIP model determined are much higher than the o nes in the conventional freezing model which is for ice production at atmos pheric pressure. The concept of equivalent ice-layer thickness delta (eq) w ith respect to the specific water film thickness delta (1), and a design gu ideline for optimal operation are also introduced in the present study. Wit h the unique feature of a spontaneous temperature gradient developed inside the ice layer of VFIP, an extremely fast and energy-saving ice-block produ ction method is found to overcome the disadvantages in energy consumption a nd ice growth rate of conventional methods.