Experimental study of the performance of open–type refrigerated display cabinet /

Abstract

This paper presents experimental investigations of the efficiency of an open-type refrigerated display cabinet used to store food at temperatures between –1 and +7 °C. The purpose of the study was to increase the efficiency of the open-type cabinet by improving its design. The cabinet has five shelves for food products with lengths of 350-600 mm. The spacing between the base and the first shelf is 280 mm, and between the other shelves it is 250 mm. The air enters the cabinet from the return air grille (RAG) at the bottom of the front panel, fans blow air through the evaporator, and the cooled air travels through a tunnel to the top of the refrigerator. The perforated distributor at the top distributes the cooled air, and part of the air is blown through the perforated back panel and the other part passes through the air-off honeycomb (dimensions (WxH) are 120x20 mm) at the front top of the cabinet, thus forming an air curtain between the inside of the refrigerator and the ambient warm air to protect the chilled food products. The cooled air entering through the perforated back panel into the display area helps maintain the required food temperature. In this study, two versions of the refrigerated cabinet were analyzed. The first version is the standard refrigeration cabinet and the second version is the same cabinet but with a change in the angle of inclination of the honeycomb and a reduction in the depth of the shelves. Air and test product temperatures were measured with thermocouples, and electrical energy consumption was measured with the Carel MT300W1100 energy meter. The experimental results show that the infiltration ratio decreases from 38.7 to 27.7%, and the 24-hour electrical consumption decreases from 24.91 to 19.22 kWh in the case of the modified cabinet. The average air temperature in the return air grille (RAG) decreased from 7.5 to 6.52 °C with the same temperature settings. The average temperature of the M packages decreased by 0.2-2.2 °C depending on the position in the refrigerator.