Numerical simulation of open refrigerated display cabinets

Abstract

Open refrigerated display cabinets are becoming more widespread since they are believed to enhance sales by providing easy access to the chilled products. Air curtains are used as a barrier between the warm ambient air and the chilled compartment of the fridge. The effectiveness of the air curtain depends on many parameters. The objective of this work is to study the effect of jet velocity, turbulence intensity and temperature on the performance of a commercial refrigerated display cabinet aiming at minimizing energy usage. A 2-D numerical model suing double precision was solved using the computational software 'Fluent' that include the full buoyancy effect and radiation between surfaces. Results include temperature variations, estimation of the entrainment of air into the fridge and heat exchanged with the ambient air in the room. The numerical results indicate that jets with lower velocities at colder temperature enhance the efficiency of the open fridge. A reduction of 19.5 percent in the air entrainment and 23 percent in the heat gain was observed in comparison with the current setting. Temperature measurements and flow visualization using smoke were conducted to validate the numerical simulation.