Refrigeration apparatus with refrigerant lubricant subcooling heat exchanger and use thereof

A refrigeration apparatus, comprising a main circuit, including:

• a compressor, including a compressor inlet and a compressor outlet,
• a condenser, including a condenser inlet, connected to the compressor outlet, and a condenser outlet,
• an expansion valve, including a valve inlet, connected to the condenser outlet and a valve outlet, and
• an evaporator, including an evaporator inlet, connected to the valve outlet, and an evaporator outlet, connected to the compressor inlet,
• wherein the main circuit is configured for a loop circulation of a main flow of refrigerant, successively through the compressor, the condenser, the expansion valve, and the evaporator,
• wherein the refrigeration apparatus further comprises a lubrication branch, comprising:
• a lubrication inlet, connected to a supply part of the main circuit, the supply part consisting of the condenser, the valve inlet, and any part of the main circuit between the condenser outlet and the valve inlet, the lubrication inlet being configured to derive a lubrication flow from the main flow of refrigerant circulating through the supply part;
• and
• a lubrication outlet, connected to the compressor so as to feed the compressor with the lubrication flow, for lubrication of said compressor with the refrigerant of the lubrication flow,
• wherein the main circuit comprises a low-temperature part, consisting of the evaporator, the compressor inlet, and any part of the main circuit between the evaporator outlet and the compressor inlet,
• wherein the lubrication branch further comprises a subcooling heat exchanger, which is configured for enabling an exchange of heat between the lubrication flow circulating through the lubrication branch and the main flow of refrigerant circulating through the low-temperature part, so that the lubrication flow may be cooled by the main flow of refrigerant circulating through the low-temperature part, within the subcooling heat exchanger;
• wherein the evaporator comprises:
• an evaporator tank, connected to the evaporator inlet so that the main flow of refrigerant is admitted within the evaporator tank;
• and
• an outlet duct, forming the evaporator outlet and connected at the top of the evaporator tank;
• wherein the subcooling heat exchanger is mounted within the outlet duct so that the main flow of refrigerant of the evaporator may flow along the subcooling heat exchanger when said main flow of refrigerant is discharged through the evaporator outlet;
• and
• wherein the lubrication branch comprises:
• an inlet connecting the lubrication inlet to the subcooling heat exchanger and extending through a connection wall of the outlet duct, and
• an outlet connecting the subcooling heat exchanger to the lubrication outlet and extending through the connection wall of the outlet duct.