Refrigeration apparatus having subcooling heat exchanger for lubrication flow

Patent metadata

Field	Value
Publication number	US-11549732-B2
Application number	US-202015930039-A
Country	US
Kind code	B2
Filing date	May 12, 2020
Priority date	May 21, 2019
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

A refrigeration apparatus, including a main circuit (1) for circulation of a main flow (90) of refrigerant, and a lubrication branch (20), comprising a lubrication inlet (21), configured to derive a lubrication flow (91) from the main flow (90) circulating through a supply part (16) of the main circuit; and a lubrication outlet (22), to feed the compressor (2) with the lubrication flow (91) for lubrication. According to the invention, the refrigeration apparatus further includes: a subcooling branch (40), comprising a subcooling inlet (41), connected to an evaporator (8) of the main circuit (1), so as to derive a subcooling flow (92), and a subcooling outlet (42), connected to the evaporator (8), for reintroducing the subcooling flow (92) into the main flow (90); and a subcooling heat exchanger (31).

First claim

What is claimed is:

1. 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 in 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 refrigeration apparatus further comprises:
a subcooling branch, comprising:
a subcooling inlet, connected to the evaporator, so as to derive a subcooling flow from the main flow of refrigerant circulating through the evaporator, and
a subcooling outlet, connected to the evaporator, for reintroducing the subcooling flow into the main flow of refrigerant circulating through the evaporator; and
a subcooling heat exchanger, being positioned outside of the evaporator, and being configured for enabling an exchange of heat between the subcooling flow circulating through the subcooling branch and the lubrication flow circulating through the lubrication branch, so that the lubrication flow may be cooled by the subcooling flow within the subcooling heat exchanger;

wherein the subcooling inlet is positioned at a lower height than the subcooling outlet, so that the subcooling flow is circulated by thermosiphon effect, when the subcooling flow is heated by the lubrication flow within the subcooling heat exchanger;
wherein the evaporator comprises an evaporator tank, flooded with refrigerant of the main flow and comprising:
a lower part, connected to:
the evaporator inlet, for conducting refrigerant of the main circuit into the lower part, and
the subcooling inlet, for deriving the subcooling flow from the lower part into the subcooling branch,

an upper part, connected to the lower part and connected to:
the subcooling outlet, for reintroducing the subcooling flow from the subcooling branch into the upper part, and
the evaporator outlet, for discharging the refrigerant from the upper part, and

wherein the evaporator comprises an outlet duct, connecting the evaporator outlet to the upper part of the evaporator tank, the duct comprising a Venturi-effect passage section reduction, the subcooling outlet being connected radially to the Venturi-effect passage section reduction so that the subcooling flow is sucked into the duct by Venturi-effect, when refrigerant is discharged from the upper part into the evaporator outlet.

2. The refrigeration apparatus according to claim 1 , wherein the subcooling heat exchanger comprises:
a heat exchange tank, belonging to a first branch chosen among the lubrication branch and the subcooling branch and being configured so that the flow of refrigerant circulating through the first branch circulates through the heat exchange tank, and
a heat exchange passage, belonging to a second branch chosen among the lubrication branch and the subcooling branch and being distinct from the first branch, the heat exchange passage being positioned within the heat exchange tank and being configured so that the flow of refrigerant circulating through the second branch circulates through the heat exchange passage.

3. The refrigeration apparatus according to claim 2 , wherein the first branch is the lubrication branch and the second branch is the subcooling branch.

4. The refrigeration apparatus according to claim 3 , wherein the lubrication branch comprises:
an inlet duct, connecting the lubrication inlet to the heat exchange tank, for circulation of the lubrication flow from the lubrication inlet to the heat exchange tank, and comprising an open inlet end positioned within the heat exchange tank for admission of the lubrication flow into the heat exchange tank; and
an outlet duct, connecting the heat exchange tank to the lubrication outlet, for circulation of the lubrication flow from the heat exchange tank to the lubrication outlet, and comprising an open outlet end positioned within the heat exchange tank, at a lower height than the open inlet end.

5. The refrigeration apparatus according to claim 2 , wherein the heat exchange tank comprises at least one liquid level sensor, detecting the presence of liquid refrigerant at a respective height within the heat exchange tank.

6. The refrigeration apparatus according to claim 2 , wherein the heat exchange passage is a coil duct.

7. The refrigeration apparatus according to claim 2 , wherein the heat exchange passage comprises a lower inlet, connected to the subcooling inlet, and an upper outlet, connected to the subcooling outlet, the lower inlet and the upper outlet being positioned at a wall of the heat exchange tank, the lower inlet being at a lower height than the upper outlet.

8. The refrigeration apparatus according to claim 1 , wherein, for being connected to the supply part, the lubrication inlet is connected to a bottom part of the condenser.

9. The refrigeration apparatus according to claim 1 , wherein the compressor is a positive displacement compressor.

10. The refrigeration apparatus according to claim 1 , wherein:
the compressor is a screw compressor comprising two meshing screw rotors, the screw rotors being supported by bearings, and
the lubrication outlet is connected to the compressor so as to feed the bearings and the screw rotors with the lubrication flow, for lubrication of said bearings and screw rotors.

11. A use of a refrigeration apparatus according to claim 1 , including:
closed loop circulation of the main flow of refrigerant successively through the compressor inlet, the compressor, the compressor outlet, the condenser inlet, the condenser, the condenser outlet, the valve inlet, the expansion valve, the valve outlet, the evaporator inlet, the evaporator, and the evaporator outlet;
derivation of the lubrication flow from the main flow of refrigerant circulating through the supply part, by the lubrication inlet;
circulation of the lubrication flow through the lubrication branch, successively through the lubrication inlet, the subcooling heat exchanger and the lubrication outlet;
derivation of the subcooling flow from the main flow of refrigerant circulating through the evaporator, by the subcooling inlet;
circulation of the subcooling flow through the subcooling branch, successively through the subcooling inlet, the subcooling heat exchanger and the subcooling outlet;
exchange of heat between the subcooling flow and the lubrication flow in the subcooling heat exchanger, so that the lubrication flow is cooled by the subcooling flow;
feeding of the compressor, by the lubrication outlet, with the lubrication flow that was cooled by the subcooling flow in the subcooling heat exchanger, for lubrication of the compressor; and
reintroduction, by the subcooling outlet, of the subcooling

Assignees

• Carrier Corp

Inventors

• Muller Raphael
• Wallet-Laily Jeremey
• Rahhal Charbel
• Barriere Antoine

Classifications

• F25B2400/0409

  for evaporators · CPC title

• F25B2400/05

  Compression system with heat exchange between particular parts of the system · CPC title

• F25B40/02

  Subcoolers · CPC title

• F25B31/002 Primary

  Lubrication · CPC title

• F25B2400/0411

  for expansion valves or capillary tubes · CPC title