Experimental study of the fins arrangement pattern of refrigerated display cabinet evaporator towards thermal performance improvement

Abstract

This paper reports the results of experimental tests performed according to ISO 23953 in an open multideck display cabinet with dual air curtain to evaluate the impact of the evaporator fins arrangement pattern on the overall thermal performance. Experimental laboratory tests were performed on climate class no. 3 (25 °C and 60%) with three different evaporator configurations. The thermal exchange area was the same among the three models to keep the aluminum fins and cooper tubes cost constant. The study investigates the increase on the operation time before defrost and the minimization of the latent thermal load due water condensation and freezing between the evaporator fins. Compared to the uniform fin pitch, it was possible to reduce 18% the frost mass and, thus, increasing the refrigeration time between defrosts and decreasing 14% the total heat load. However, an increase on the air (+0.6 °C) and product temperatures (+1.9 °C) due to an inefficient heat exchange, leads to new analysis and assessments related to the residence time between the fins and the airflow in order to keep the temperatures low at the refrigerated space and thus ensuring food safety.