Sammendrag
The study is devoted to the investigation of heat transfer phenomena of Atlantic salmon in refrigerated sea water with the aim to clarify strategies of large scale industrial chilling of big-size fishes. Experiments were conducted using polyurethane copies of real fishes (3.5 and 6.0 kg), which were equipped with temperature sensors at different points. Convective heat transfer coefficient was determined with a numerical model. Tests were verified using real slaughtered salmon. A simplified solution for transient problem was suggested. Convective heat transfer coefficient varied between 16.0 and 300 W m-2 K-1 with respect to chilling mode. High values of convective heat transfer coefficient (over 200 W m-2 K-1) requires high flow of cooling agent even for laboratory scale chilling tank. Experiments at industrial slaughter house revealed convective heat transfer coefficient in the range between 112.0 and 139.0 W m-2 K-1. Simulation showed that the target temperature of 2.0 °C in the fish centre is difficult to achieve, when strict time limits are applied at factory, especially for fishes over 5.0 kg weight.