CFD comparisons of open-type refrigerated display cabinets with/without air guiding strips

Abstract

Open-type vertical refrigerated display cabinets are used widely in supermarkets and grocery stores due to its attraction for customers and food merchandisers. These cabinets, however, are less energy efficient than cabinets with glass doors because of the interactions between the air curtain, that is used to provide an artificial barrier between the air in the cabinets, and the air in food premises. To improve the energy efficiency of open fronted refrigerated display cabinets, many types of air curtains have been designed, including single layer air curtains, multi-layer air curtains and shelf tip air curtains amongst others. An approach, considered in recent years to improve the efficiency of air curtains is the use of air guiding strips at the front face of the shelves of open-type vertical refrigerated display cabinets with single layer air curtains. This paper uses Computational Fluid Dynamics modelling to investigate the influence of air guiding strips on the performance of vertical multi-deck refrigerated display cabinets. The results showed that the air guiding strips accelerate the air curtain vertically; leading to a stronger and stiffer air curtain, consequently inhibit the infiltration of the ambient warm air into the cabinet. The average temperature of simulated food in the cabinet decreases by 4.9°C compared to the cabinet without the strip due to the improved protection of the stiffer air curtain. The cooling capacity required to maintain the food chilled decreases by 34%.