Heat transfer model of halibut, freezing and thawing - an opportunity for further value creation

The Matís report "Freezing and thawing of halibut - experiments and CFD simulation" has been published, which was prepared in the project Simulation of cooling processes. 

The freezing and thawing of halibut was experimentally studied and CFD models were constructed using the thermal and hydrological software FLUENT. The project has already demonstrated the unequivocal utility of such models for the transport processes of fresh produce, but the results of this report show that the same applies to frozen products. 

In the freezing experiment, whole pallets of semi-frozen halibut were placed in a cold store and the air temperature and the temperature of halibut in different places on the pallet were measured with thermometers. The time taken for the halibut to freeze from -10 to -5 ° C below -15 ° C ranged from one to four days depending on the location of the pallet. 

In thawing experiments, both individual bags and twenty bags, stacked on pallets, were examined in the temperature-controlled cold rooms of Matís and UI. Heating of a frozen product was mapped under conditions that may occur during unloading from freezer trawlers or 10 - 20 ° C air temperature. The results of the experiments were compared with the results of three-dimensional heat transfer models, and there was generally a good agreement between them. At 10 p.m. storage at 12.6 ° C air temperature raised the temperature in individual bags from about -26 ° C to approx. -5 ° C. At such a long temperature load, the temperature in pallet bags rose from -22.5 ° C to -17 to -3 ° C, which shows how homogeneous the heat distribution can be with prolonged heat load. The results of the CFD model showed that 10 m / s wind during loading significantly accelerates the thawing of frozen fish on pallets.

For further information, please contact Björn Margeirsson, PhD student at Matís and the University of Iceland, bjorn.margeirsson@matis.is.