Heat transfer modelling in a refrigerated display cabinet: The influence of operating conditions

The product temperature in refrigerated display cabinets is very variable and directly influences the safety and quality of food products. This variability is due to the type of display cabinet (vertical, horizontal), the position of the product inside the cabinet, fluctuations in the ambient temperature in supermarkets (day/night, opening hours, seasons, air conditioning, etc.) and the surrounding conditions of the display cabinet (in front of another refrigerated display cabinet or in front of grocery products. etc.). This study proposes a heat transfer model to predict the load temperature in an open vertical display cabinet. Heat transfer by conduction, convection and radiation was taken into account in the model. Four load positions were considered: top/front, top/rear, bottom/front and bottom/rear where the product temperatures are significantly different. The model was validated by comparing predicted values with experimental ones. Then it was used to predict the influence of various parameters such as the ambient temperature in the supermarket, the radiation temperature of the surrounding walls and the internal/external infiltration rates. Through integration of quality and microbiological predictive models, this approach can be used as a numerical tool for quality and sanitary evaluation of products displayed in display cabinets. The developed model will be further used in the modelling of the cold chain, which comprises several types of refrigeration equipment. (C) 2011 Elsevier Ltd. All rights reserved.