Energy consumption reduction strategy for freezing of packaged food products

Abstract

In this work, a model of the process of freezing strawberries placed in boxes using forced air tunnel was studied. A strategy of operating condition modification in each stage of the process (pre-cooling, freezing step and sub-cooling) was applied, in a simulated process, regarding air temperature change. Time and energy consumption behaviors due to air temperature conditions in the tunnel were evaluated for each stage. Air temperature at different process stages affected both process times and system thermal demands. Operating conditions for each stage, which provided the best system global performance, were chosen, aiming energy consumption reduction without damaging product final quality, once each stage minimum requirements were taken into account. The strategy proposed produced an energy economy of 5.9%, comparing to the traditional process using constant temperatures, and it showed potential to be applied in different products and equipment with appropriate changes in the methodology.