Experimental Analysis of Aerothermodynamics Performance of the Air Curtain Subject to the Systematic Crossing of a Solid Body

摘要

Vertical open refrigerated multideck display cabinets (VORDC) are widely used to display perishable products in supermarkets and convenience stores. During the daily operation of food stores, consumers and repository personnel pass in front of VORDC and frequently remove or place food products on shelves. This movement is part of the trade, however it has consequences on the thermal performance of the VORDC. Each interference drags or breaks the air curtain of the equipment resulting in the modification of air flow and promoting the ambient air thermal entrainment that consequently changes the equipment's operative conditions. This paper reports the results of experimental tests performed according to ISO 23953 in a VORDC to assess the thermal performance of the air curtain when subjected to the systematic crossing by a solid body simulating people arms. This solid body consists on a moving electromechanical device composed by a set of pneumatic cylinders that allows several patterns of air curtain interference. The experimental laboratory tests were conducted for climate class n.° 3 of ISO23953 (25 C dry bulb temperature and 60% of relative humidity). The analysis of results shows an increase of the electrical energy consumption of the VORDC due to the air curtain breaking by an automated solid body's structure simulating people arms extracting food products from the VORDC. Experimental tests were developed for periods of 150 sec and 100 sec of the solid bodies crossing the air curtain. The comparison of results of the two case studies allows concluding that the air curtain interference occurred every 100 sec increases the energy consumption by approximately 2.5%, even though it does not influence significantly the food products temperature. The analysis of these experimental results provides valuable information to set the operative parameters of the VORDC taking into account usual in-store conditions, both environmental and consumers' traffic.