Showcases should refrigeration equipment to adequately cool the air, which, in turn, contrasts numerous heat gains to store the products at the correct temperature. Depending on refrigeration equipment, display cases can be classified as integral units, including own condensing units or as a remote cabinets with remote condensing units. In the cabinets of the first type, the fridge is contained in a device that only requires connection of power supply and for this reason is called a standalone device. If this unit open-drain, it is sometimes necessary to evacuate the water after thawing (in closed cabinets, less water is produced that can be removed by evaporation). In remote cabinets, UPS is connected to the Central refrigeration system, which serves the entire low-temperature cabinets in a supermarket; only the evaporator and extend the device are provided in box, while the compressor and condenser are beyond the scope of sales.
In order to reduce the quantity of refrigerant required for the system, you can use the secondary fluid, which is cooled in a centralized cooling system and distributed to spread the refrigeration capacity of all cabinets (indirect cooling systems).
This kind of system is less energy efficient, however, it allows the significant reduction in the overall amount of the refrigerant, and makes possible the use of toxic or flammable refrigerants, with the cooling system may be limited. This is an important question because refrigerants, adopted in remotely-controlled cooling systems almost fully halogenated hydrocarbons, where strong pressure is being put to the use of natural refrigerants such as ammonia, carbon dioxide and hydrocarbons. In this section we will examine in the next section.
That means, refrigeration adopted, one or more cooling coils are used in cabinets for cooling air. Because their surface temperature is below 0C (usually below 35C), a cooling coil frost deposition due to dehumidify the air. This is especially true in the case of open cabinets, where the penetration of air from the environment occurs, and this is emphasised in the warm and humid climate. In thawing it is therefore necessary, whose exploitation should be cyclical and are able to keep the coil and any ducts ice. In addition to the power consumption of this device, an important consequence of its use is an inevitable increase in temperature products, due to the lack of any cooling effect during thawing and undesirable heat supply...