Refrigeration systems and refrigeration equipment

Abstract

The present invention provides a refrigeration system and refrigeration equipment, which relate to the technical field of heat pump systems, and provide a new refrigeration system for improving the energy efficiency of compressors. The device includes a compressor, an evaporator and a condenser, and also includes an expander and an economizer, wherein the expander is connected to the compressor, the expander is connected to the economizer, and the economizer is arranged between the condenser and the evaporator. The refrigerant flowing to the economizer after throttling can flow to the expander after passing through the economizer so as to be used for the expander to assist the operation of the compressor. The refrigeration system provided by the present invention combines the expander and the compressor together, and outputs work (torque) through the expander and inputs it to the compressor, thereby reducing the output torque of the compressor's own motor, thereby improving the energy efficiency of the entire machine. The refrigerant discharged from the economizer is used to flow to the expander, so as to fully utilize the energy of the high-temperature and high-pressure refrigerant after condensation by the condenser.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump systems, and in particular to a refrigeration system and refrigeration equipment. Background Art

[0002] In the field of refrigeration technology, how to save energy and increase efficiency is a technical research topic that the industry is constantly pursuing optimization, but it often faces the problem of either damaging other performance of the refrigeration equipment or seriously increasing the complexity of system operation. In the operation of the screw unit system, how to make full use of the energy of the high-temperature and high-pressure refrigerant condensed by the condenser is the current development direction of the industry's research on improving the energy efficiency of screw compressors.

[0003] See also Figure 1 , which is a schematic diagram of the refrigeration cycle of a conventional screw unit system. The two-stage compressor 1 compresses and discharges high-temperature and high-pressure gas, which is condensed by the condenser 2 and becomes a high-temperature and high-pressure liquid. Then, a refrigerant is diverted through the economizer 3 and passes through the expansion valve 4 to exchange heat with the main circuit in the economizer 3 to become medium-temperature and medium-pressure gas, which enters the medium-pressure chamber of the two-stage compression unit 1 for air replenishment and enthalpy increase; while the main circuit refrigerant continues to pass through the expansion valve 4 and the evaporator 5 to become a low-temperature and low-pressure gas and enter the inlet of the two-stage compression unit 1 for a compression cycle. Summary of the invention

[0004] The purpose of the present invention is to provide a refrigeration system and a refrigeration device, and to provide a new refrigeration system for improving the energy efficiency of a compressor. The preferred technical solutions among the many technical solutions provided by the present invention can produce many technical effects as described below.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A refrigeration system provided by the present invention includes a compressor, an evaporator and a condenser, and also includes an expander and an economizer, wherein the expander is connected to the compressor, the expander is connected to the economizer, and the economizer is arranged between the condenser and the evaporator. The refrigerant flowing to the economizer after throttling can flow to the expander after passing through the economizer so that the expander can assist the operation of the compressor.

[0007] Furthermore, a bypass pipe connected in parallel with the expander is provided on the refrigeration system or a bypass pipe is provided in the expander, and opening the bypass pipe enables the refrigerant flowing out of the economizer to flow to the branch air intake port of the compressor through the bypass pipe.

[0008] Furthermore, a one-way valve is arranged on the bypass pipeline.

[0009] Furthermore, an air supply circuit is provided on the refrigeration system, and an air supply port is provided on the compressor, and the air supply port is connected to the air supply circuit.

[0010] Furthermore, the compressor is a two-stage screw compressor, which includes a first screw compression unit and a second screw compression unit. The refrigerant discharged from the evaporator enters the first screw compression unit through the main air intake port of the compressor, and the gas discharged from the first screw compression unit and the gas entering the air supply port can enter the second screw compression unit.

[0011] Furthermore, the refrigeration system further comprises a flash evaporator, which is arranged between the economizer and the evaporator, and an exhaust port of the flash evaporator is connected to an air supply circuit.

[0012] Furthermore, an expansion valve is provided at the liquid inlet side of the flash evaporator and between the flash evaporator and the evaporator.

[0013] Furthermore, the expander is a screw expander.

[0014] Furthermore, the expander output shaft is connected to the motor shaft of the compressor via a coupling.

[0015] A refrigeration device comprises the refrigeration system.

[0016] The present invention provides a refrigeration system, including a compressor, an evaporator and a condenser, and also including an expander and an economizer, wherein the expander is connected to the compressor, the expander is connected to the economizer, the economizer is arranged between the condenser and the evaporator, and the refrigerant flowing to the economizer after throttling can flow to the expander after passing through the economizer so as to be used by the expander to assist the operation of the compressor. The refrigeration system provided by the present invention combines the expander and the compressor together, and outputs work (torque) through the expander and inputs it to the compressor, thereby reducing the output torque of the compressor's own motor, thereby improving the energy efficiency of the entire machine. The refrigerant discharged from the economizer is used to flow to the expander, so as to fully utilize the energy of the high-temperature and high-pressure refrigerant after condensation by the condenser. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is the schematic diagram of the refrigeration cycle of a conventional screw unit system;

[0019] Figure 2 It is a refrigeration cycle principle diagram of the screw unit system provided by the present invention;

[0020] Figure 3 It is a structural schematic diagram of the expander output shaft provided by the present invention being connected to the motor shaft of the compressor via a coupling.

[0021] In the figure, 1- compressor; 2- condenser; 3- economizer; 4- expansion valve; 5- evaporator; 6- first coupling; 7- expander; 8- flash unit; 9- second coupling; 10- motor; 11- first screw compression unit; 12- second screw compression unit; 13- one-way valve; 14- bypass pipe; 15- screw inside the expander. DETAILED DESCRIPTION

[0022] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0023] The present invention provides a refrigeration system, comprising a compressor 1, an evaporator 5 and a condenser 2, and also comprising an expander 7 and an economizer 3, wherein the expander 7 is connected to the compressor 1, the expander 7 is connected to the economizer 3, the economizer 3 is arranged between the condenser 2 and the evaporator 5, and the refrigerant flowing to the economizer 3 after throttling can flow to the expander 7 after passing through the economizer 3 so that the expander 7 can assist the operation of the compressor 1. Figure 1 , compressor 1 compresses and discharges high-temperature and high-pressure gas, which is condensed into high-temperature and high-pressure liquid through condenser 2, and then diverted through economizer 3 to a refrigerant path, which is heat-exchanged with the main path through expansion valve 4 in economizer 3 to become sub-high-temperature and sub-high-pressure gas, and enters the inlet of expander 7, operates to output work (torque), and discharges low-temperature and low-pressure gas to flow to compressor 1. The refrigeration system provided by the present invention combines expander 7 and compressor 1 together, outputs work (torque) through expander 7, and inputs it to compressor 1, thereby reducing the output torque of the motor of compressor 1, and then improving the energy efficiency of the whole machine. The refrigerant discharged from economizer 3 flows to expander 7, so as to fully utilize the energy of the high-temperature and high-pressure refrigerant after condensation by the condenser.

[0024] As an optional implementation, a bypass pipe 14 connected in parallel with the expander 7 is provided on the refrigeration system or a bypass pipe 14 is provided in the expander 7. Opening the bypass pipe 14 allows the refrigerant flowing out of the economizer 3 to flow to the branch air intake port of the compressor 1 through the bypass pipe 14. When operating under large pressure difference conditions, the high-temperature and sub-high-pressure gas entering the expander 7 can drive the expander 7 to rotate. However, when operating under low pressure difference conditions, the exhaust pressure is lost through system circulation, and the pressure of the refrigerant entering the expander 7 is too small to drive the rotor of the expander 7 to rotate, or it can drive the rotor of the expander 7 to rotate but the torque generated is very small. In this case, a bypass solution is adopted, the bypass pipe 14 is opened, and the refrigerant discharged to the expander 7 is directly bypassed to the exhaust side of the expander 7 through the bypass pipe 14, so that the rotor of the expander 7 is allowed to idle.

[0025] The bypass pipe 14 may be arranged outside the expander 7, that is, the bypass pipe 14 connected in parallel with the expander 7 is arranged on the refrigeration system, a control valve is arranged on the bypass pipe 14 to control the conduction state of the bypass pipe 14, and a check valve 13 is arranged on the bypass pipe 14 to avoid backflow. The bypass pipe 14 may also be arranged in the expander 7 by changing the structure of the expander 7.

[0026] As an optional implementation, the refrigeration system is also provided with an air supply circuit, and the compressor 1 is provided with an air supply port, which is connected to the air supply circuit. The air supply circuit is specifically described as follows: the refrigeration system also includes a flash evaporator 8, which is arranged between the economizer 3 and the evaporator 5, and the exhaust port of the flash evaporator 8 is connected to the air supply circuit. An expansion valve 4 is arranged on the liquid inlet side of the flash evaporator 8 and between the flash evaporator 8 and the evaporator 5. The use of the flash evaporator 8 to supply air has a simple structure and a good air supply effect. Figure 1 , compressor 1 compresses and discharges high-temperature and high-pressure gas, which is condensed into high-temperature and high-pressure liquid through condenser 2, and then diverted through economizer 3 to a path of refrigerant, which is heat-exchanged with the main path through expansion valve 4 in economizer 3 to become sub-high-temperature and sub-high-pressure gas, and enters the inlet of expander 7, operates to output work (torque), and discharges low-temperature and low-pressure gas. The main path refrigerant continues to pass through expansion valve 4 to become medium-temperature and medium-pressure liquid and enters flash evaporator 8, which diverts a path of medium-temperature and medium-pressure gas into compressor 1 for air replenishment and enthalpy increase. The liquid refrigerant in flash evaporator 8 continues to pass through expansion valve 4 and evaporator 5 to become low-temperature and low-pressure gas, which is mixed with the gas discharged from expander 7 and then enters the inlet of two-stage compression unit 1 to perform compression cycle.

[0027] The expander 7 is a screw expander, and the compressor 1 is a two-stage screw compressor. The compressor 1 includes a first screw compression unit 11 and a second screw compression unit 12. The refrigerant discharged from the evaporator 5 enters the first screw compression unit 11 through the main air intake port of the compressor 1, and the gas discharged from the first screw compression unit 11 and the gas entering the air replenishment port can enter the second screw compression unit 12. The output shaft of the expander 7 is connected to the motor shaft of the compressor 1 through a coupling to achieve a structural integrated design. The economizer 3 is used to divert a sub-high temperature and sub-high pressure gas for the operation of the expander 7 and output torque to assist the motor 10 in driving the two-stage screw compressor, reduce the output torque of the motor 10, and thus improve the energy efficiency of the screw machine.

[0028] The two-stage screw compressor is rigidly connected by the motor 10 and the first screw compression unit 11, and then connected to the second screw compression unit 12 through the second coupling 9. The two-stage screw compressor is formed with three air intake inlets (i.e., the main air intake inlet, the branch air intake inlet, and the air supply inlet) and one exhaust outlet. The refrigerant passes through the expander 7 and mixes with the refrigerant in the main air intake inlet to cool the motor 10 together, and then enters the first screw compression unit 11 of the compressor 1 for primary compression. After compression, the refrigerant is mixed with the refrigerant entering the air supply inlet, and then enters the second screw compression unit of the compressor 1 for secondary compression, and finally discharged through the exhaust outlet.

[0029] A refrigeration device includes the refrigeration system provided by the present invention. The refrigeration system includes a compressor 1, an evaporator 5, and a condenser 2, and also includes an expander 7 and an economizer 3, wherein the expander 7 is connected to the compressor 1, and the expander 7 is connected to the economizer 3, and the economizer 3 is arranged between the condenser 2 and the evaporator 5. The refrigerant flowing to the economizer 3 after throttling can flow to the expander 7 after passing through the economizer 3 so that the expander 7 can assist the operation of the compressor 1. The refrigeration system provided by the present invention combines the expander 7 and the compressor 1 together, and outputs work (torque) through the expander 7 and inputs it to the compressor 1, thereby reducing the output torque of the motor of the compressor 1, thereby improving the energy efficiency of the whole machine.

[0030] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A refrigeration system, comprising a compressor (1), an evaporator (5) and a condenser (2), characterized in that: It also includes an expander (7) and an economizer (3), wherein: The expander (7) is connected to the compressor (1), and the expander (7) is connected to the economizer (3). The economizer (3) is arranged between the condenser (2) and the evaporator (5). The refrigerant flowing to the economizer (3) after throttling can flow to the expander (7) after passing through the economizer (3) so as to be used by the expander (7) to assist the operation of the compressor (1); A bypass pipe (14) is provided in the expander (7), and opening the bypass pipe (14) enables the refrigerant flowing out of the economizer (3) to flow through the bypass pipe (14) to the bypass air intake port of the compressor (1); When operating under a large pressure difference condition, the sub-high temperature and sub-high pressure gas entering the expander (7) can drive the expander (7) to rotate; when operating under a low pressure difference condition, the exhaust pressure is lost through system circulation, and the pressure of the refrigerant entering the expander (7) is too low, so the bypass pipe (14) is opened, and the refrigerant discharged to the expander (7) is directly bypassed to the exhaust side of the expander (7) through the bypass pipe (14); A one-way valve (13) is provided on the bypass pipe (14); The refrigeration system is also provided with an air supply circuit, and the compressor (1) is provided with an air supply port, the air supply port being connected to the air supply circuit; The compressor (1) is a two-stage screw compressor, comprising a first screw compression unit (11) and a second screw compression unit (12); the refrigerant discharged from the evaporator (5) enters the first screw compression unit (11) through the main air intake port of the compressor (1); the gas discharged from the first screw compression unit (11) and the gas entering through the air intake port can enter the second screw compression unit (12); The output shaft of the expander (7) is connected to the motor shaft of the compressor (1) via a coupling.

2. The refrigeration system according to claim 1, characterized in that: The refrigeration system further comprises a flash evaporator (8), wherein the flash evaporator (8) is arranged between the economizer (3) and the evaporator (5), and an exhaust port of the flash evaporator (8) is connected to an air supply circuit.

3. The refrigeration system according to claim 2, characterized in that: An expansion valve (4) is provided on the liquid inlet side of the flash evaporator (8) and between the flash evaporator (8) and the evaporator (5).

4. The refrigeration system according to claim 1, characterized in that: The expander (7) is a screw expander.

5. A refrigeration device, characterized in that: A refrigeration system comprising any one of claims 1 to 4.

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