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

A new vacuum freezing ice production (VFIP) method based on the solid‐liquid‐vapor multiple phase transformation and the latent‐heat coupling mechanism is introduced in the present study. Coupled heat and mass flux equations based on irreversible thermodynamics have been applied to depict the ice growing phenomenon under vacuum, and to derive an equation for its growth rate. Ice growth rates of the VFIP model determined are much higher than the ones in the conventional freezing model which is for ice production at atmospheric pressure. The concept of equivalent ice‐layer thickness δeq with respect to the specific water film thickness δl , and a design guideline for optimal operation are also introduced in the present study. With the unique feature of a spontaneous temperature gradient developed inside the ice layer of VFIP, an extremely fast and energy‐saving ice‐block production method is found to overcome the disadvantages in energy consumption and ice growth rate of conventional methods.