| Summary: | Freezing time and freezing heat load are the two most importantfactors determining the economics of food freezers. ThisBrief willreview and describe the principal methods available for theircalculation. The methods can be classified into analytical methods, which rely on making physical simplifications to be able to deriveexact solutions; empirical methods, which use regression techniques to derive simplified equations from experimental data or numericalcalculations and numerical methods, which use computationaltechniques such as finite elements analysis to solve the complete set of equations describing the physical process. TheBrief willevaluate the methods against experimental data and develop guidelineson the choice of method. Whatever technique is used, the accuracy ofthe results depends crucially on the input parameters such as the heat transfer coefficient and the product's thermal properties. In addition, theestimation methods and data for these parameters will be reviewed andtheir impacts on the calculations will be evaluated. Freezing is oftenaccompanied by mass transfer (moisture loss, solute absorption), super cooling and nucleation and may take place under high pressureconditions; therefore methods to take these phenomena into accountwill also be reviewed.
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