Refrigerated counters covers a considerable number of applications, it becomes necessary to study the various counters used in these applications, which vary widely in size, shape and style, in each case: grocery counters, supermarkets; counters for storage, preservation of fresh meat, beverages and milk; showcases for meats of all kinds, including a special type for fresh fish and also a type where the lower part of the counter is used for storage purposes; ice cream counters and counters for superfrozen foods. The display of frozen food is a new burgeoning commercial refrigeration application.
Many models have a "refrigerated" space for storage, below the part dedicated to showcase with the respective serpentine connected in series with the upper serpentines. The temperature can be maintained between (4,4ºC) and (7,2ºC) in both compartments, or higher if you wish, since it is a temporary storage, and the food must be transferred at night to the storage chamber.
Higher temperature counters, such as for meat, dairy products, etc., do not present any problem with the serpentine. Fan coils are used, and there are ducts that conduct cold air through grills at the rear of the counter at the same level as the food, returning hot air from the front and from below.
Low temperature units for frozen food display have a difficult problem with the defrost of the coil, which must be done quickly so that the counter does not get too hot. The defrost can be done automatically by means of a time relay, which activates a hot gas defrost system, or by means of an electric resistance.
It has become very common to combine frozen food storage and showcase. A temperature close to (-17,8 ° C) should prevail in the displays. Under these conditions, the coils should operate from -23.3 ° C to -26.1 ° C and need to be frequently defrosted. Throughout the display parts heating wires are arranged to prevent the condensation of moisture from the air.
