Performance optimization of a secondary refrigerant display cabinet using tests and CFD modelling

In this paper a computational investigation to address some of the design parameters that have significant effects on the performance of a secondary refrigerant refrigerated display cabinet is presented. The investigated design parameters include air curtain velocity, width, discharge angle and positioning of the air curtain outlet from the front edge of the display cabinet’s top shelf. In addition the effect of using honeycomb on the flow path at the air curtain outlet was also investigated. A 3D CFD model was constructed to assess the effect of the side flow on the performance of the vertical display cabinet. The suitability of using 2D CFD to carry out the display cabinet design optimization was investigated and it was concluded that for the length of the cabinet considered, the flow could be assumed to be two-dimensional for most of the cabinet length. The results also indicated that the optimum air curtain mass flow rate constituted approximately a third of the total air mass flow rate. For the geometry considered with respect to air curtain discharge and top shelf outer edge position it was found that shaping the honeycomb to produce more uniform flow and reduce recirculation at the inner edge of the air curtain outlet improved the air curtain performance and led to a 4% reduction in the cabinet load.