PREDICTION OF TEMPERATURE IN FROZEN FOODS EXPOSED TO SOLAR RADIATION

Abstract

Simultaneous convective and radiative boundary conditions were incorporated into a one-dimensional three time level implicit finite difference scheme in rectangular coordinates. The scheme was used to calculate temperature profiles and temperature histories in a packaged frozen food exposed to the sun. The solution was verified by thawing slabs of a standard test material (Karlsruhe test substance) and orange juice in different environments. Procedures were developed to measure the temperature distribution and to estimate the radiation properties of the package surface. The maximum thickness of the slabs was 38 mm. The agreement between experimental and predicted food surface and center temperature profiles was determined by corresponding R2 values ranging from 0.872 to 0.998. The computer program was also used to predict temperature profiles in a 100 × 92 × 92-cm pallet of frozen food exposed to different environmental conditions. Conditions were cimulated by varying initial product temperature, product thermal properties, air resistance between the product and the package, external heat transfer coefficient, ambient temperature, and radiation surface properties of the carton.