Aero- and thermodynamical optimization of cooling tunnels for chocolate systems

The cooling process is an important step during the chocolate production. It influences the final product qualities such as gloss, texture, and melting behavior. In this work, the aero- and thermodynamical aspects of the cooling of chocolate systems were investigated. By improving the aerodynamic conditions, an improvement of 10% of the overall heat transfer could be realized. When coupling these findings with high thermal conductive material, this resulted in up to 15% of faster cooling. Further, the modelling of the cooling process was a crucial tool to improve the cooling process. Here a validated model was used to investigate the impact of elements, such as the edge height, rim length of the mold, and pater noster elbows, and the direction of cooling air flow on the aerodynamic conditions and the resulting heat transfer from the chocolate to the air. In addition, to the computational fluid dynamics model, heat flux sensors and particle image velocimetry was used to gain a deep insight. To complete the toolbox, inline measuring techniques were further introduced and refined to detect crystallization and detachment behavior, as well as the resulting chocolate surface structures