An investigation into economical energy usage in freezing tunnels in a food processing industry was conducted. Typically, large amounts of electricity are consumed in these tunnels. An actual freezing tunnel at a citrus processing plant was studied experimentally to determine its operating characteristics, and a temperature profile of concentrate along the length of the tunnel was obtained. A computer model was also developed, and predicted temperature profiles were compared to experimental data.

A parametric study was performed to determine the effect of the bed velocity, ambient tem­perature, internal fan loads, and can spacing on the tunnel bed. Methods for improving the ef­fectiveness of the freezing tunnels, both in existing and future designs, are discussed. It was concluded that a factor, K, defined here as the ratio of fan work divided by the useful refrigeration effect, was the most important indicator of economical energy usage in the freezing tunnel.