Single-machine double-system type hot fluorine defrosting refrigerating system

Abstract

The invention relates to the technical field of refrigerating systems, and discloses a single-machine double-system type hot fluorine defrosting refrigerating system which comprises a main machine refrigerating system, an auxiliary machine refrigerating system and two gas-liquid separators, the main machine refrigerating system comprises a first-stage compressor, a first-stage condenser, a first-stage expansion valve and a first-stage evaporator, and the auxiliary machine refrigerating system comprises a second-stage compressor, a second-stage condenser, a second-stage expansion valve and a second-stage evaporator; the auxiliary machine refrigeration system comprises a second-stage compressor, a second-stage condenser, a second-stage expansion valve, a second-stage evaporator, a third-stage condenser, a third-stage expansion valve and a third-stage evaporator. According to the technical scheme, the double refrigeration circulation paths are introduced into the refrigeration system, during refrigeration, the main machine refrigeration system is responsible for refrigeration, the auxiliary machine refrigeration system supplies liquid to the main machine refrigeration system for undercooling, the heat load is relieved, and the unit refrigeration capacity is improved; in the defrosting process, the auxiliary machine refrigeration system is adopted for generating high-temperature and high-pressure hot fluorine for defrosting, the energy consumption of hot defrosting is reduced, fire hazards caused by aging of electric heating elements are avoided, and the safety coefficient of system operation is improved.

Description

Technical Field

[0001] This invention relates to the field of refrigeration system technology, and in particular to a single-unit dual-system hot refrigerant defrosting refrigeration system. Background Technology

[0002] With the increasing demand for comfortable living environments in modern society, refrigeration systems are being used more and more widely. Traditional refrigeration methods mainly rely on compressors, which convert refrigerant into a high-temperature, high-pressure state. The refrigerant is then cooled and liquefied in a condenser, and its pressure is further reduced by an expansion valve, converting it to a low-temperature, low-pressure state. In the evaporator, heat is absorbed, achieving the cooling effect. Traditional refrigeration systems often employ a single-system design. When the heat load increases, the compressor needs to operate at a high load continuously, leading to a sharp drop in energy efficiency. Furthermore, during long-term operation, frost and ice easily accumulate on the evaporator surface, severely impacting its refrigeration efficiency, increasing system energy consumption, and reducing cooling performance. Therefore, to ensure efficient operation of the refrigeration system, effective defrosting of the evaporator surface is necessary. However, traditional refrigeration systems often use electric heating for defrosting, which is energy-intensive, poses a high fire risk, and suffers from refrigerant leakage due to the high failure rate of single-system thermal defrosting.

[0003] Therefore, the aforementioned technical problems need to be solved. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention proposes a single-unit dual-system hot refrigerant defrosting refrigeration system to solve the problems of a sudden drop in energy efficiency caused by the compressor needing to operate at high load continuously when the heat load increases in a single-system refrigeration system; the high energy consumption and fire risk associated with electric heating for defrosting; and the refrigerant leakage caused by the high failure rate of hot refrigerant defrosting in a single-unit system.

[0005] To solve the above-mentioned technical problems, the basic technical solution proposed by this invention is as follows: A single-unit dual-system hot fluorine defrosting refrigeration system includes a main refrigeration system, a secondary refrigeration system, and two gas-liquid separators. The main refrigeration system includes a first-stage compressor, a first-stage condenser, a first-stage expansion valve, and a first-stage evaporator. The first-stage compressor, the first-stage condenser, the first-stage expansion valve, and the first-stage evaporator are connected in series to form a closed-loop refrigeration main circulation path. The auxiliary refrigeration system includes a two-stage compressor, a two-stage condenser, a two-stage expansion valve, a two-stage evaporator, a three-stage condenser, a three-stage expansion valve, and a three-stage evaporator; The three-stage condenser is connected in parallel with the two-stage condenser. The two-stage compressor is connected to the input terminals of the two-stage and three-stage condensers through a three-way valve A. The flow direction of the refrigerant output from the two-stage compressor is switched through the three-way valve A. The outputs of the secondary and tertiary condensers are connected to the secondary and tertiary expansion valves via a three-way valve B. The three-way valve B controls the switching of the refrigerant flow direction output from the secondary and tertiary condensers. The secondary expansion valve is connected in series with the secondary evaporator, the tertiary expansion valve is connected in series with the tertiary evaporator, and the tertiary evaporator is connected in parallel with the main refrigeration system through solenoid valve B and is located after the primary condenser. A two-stage compressor, a three-stage condenser, a three-stage expansion valve, and a three-stage evaporator are connected in series to form an auxiliary subcooling path; The secondary compressor, secondary condenser, secondary expansion valve, and secondary evaporator are connected in series to form a closed-loop refrigeration secondary circulation path. The secondary compressor is connected in series with the primary evaporator and the tertiary evaporator through the defrost solenoid valve pipeline to form a defrost path.

[0006] Preferably, the two gas-liquid separators are connected in parallel in the main refrigeration system and the auxiliary refrigeration system via solenoid valve A, respectively.

[0007] Preferably, the two gas-liquid separators are respectively located between the outlet of the first-stage evaporator and the inlet of the first-stage compressor, and the two gas-liquid separators are respectively located at the outlet of the first-stage evaporator and the outlet of the third-stage evaporator.

[0008] Preferably, the three-stage expansion valve is located between the two-stage condenser and the three-stage evaporator to achieve independent expansion control of the auxiliary subcooling path.

[0009] Preferably, the tertiary expansion valve and the secondary expansion valve are designed in series via a three-way valve B, and the refrigerant flow direction is controlled by the three-way valve B.

[0010] Preferably, the tertiary evaporator is connected before the secondary compressor via a solenoid valve C, and the secondary compressor and the tertiary evaporator are dynamically switched via the solenoid valve C to adapt to different operating conditions.

[0011] The beneficial effects of this invention are: The technical solution of this invention introduces a dual refrigeration cycle path into the refrigeration system. During refrigeration, the main refrigeration system is responsible for refrigeration, while the auxiliary refrigeration system assists in refrigeration by supplying liquid subcooling to the main refrigeration system, thereby reducing the heat load. In the main refrigeration cycle, the first-stage compressor drives the basic refrigeration cycle, while the auxiliary refrigeration system switches to the auxiliary subcooling path via a three-way valve. The third-stage evaporator acts as a subcooler, utilizing the cooling capacity generated by the compressed refrigerant in the auxiliary unit to perform secondary cooling on the liquid refrigerant at the outlet of the first-stage condenser, thereby increasing the degree of subcooling. This reduces flash gas after throttling, increases the unit refrigeration capacity, and simultaneously reduces the heat load of the main refrigeration system. The system energy efficiency of the dual-system coordinated operation is significantly higher than the sum of the efficiencies of a single system operating independently, effectively solving the problem of energy efficiency degradation under heavy heat loads. During defrosting, the main refrigeration system stops operating, and the auxiliary refrigeration system switches to defrosting mode. The auxiliary refrigeration system generates high-temperature and high-pressure hot refrigerant for defrosting. The auxiliary refrigeration system switches to the defrosting path through a three-way valve: the high-temperature and high-pressure gas generated by the secondary compressor passes through the defrosting solenoid valve tube directly to the surface of the primary and tertiary evaporators, and directly melts the frost layer by utilizing the latent heat of phase change of the refrigerant. Compared with electric heating defrosting, this solution uses heat to directly defrost, which improves the defrosting effect of the system, reduces the energy consumption of thermal defrosting, and avoids the fire hazard caused by the aging of electric heating elements. Through the intelligent switching of the three-way valve, the main refrigeration system and the auxiliary refrigeration system achieve complete physical isolation. In refrigeration mode, the auxiliary unit operates independently as a subcooler. In defrost mode, the main unit stops while the auxiliary unit starts a dedicated defrost path. The dual-system independent control architecture ensures that hot refrigerant defrosting is completed only in the auxiliary refrigeration system, avoiding frequent impacts of high-temperature and high-pressure gases on the main evaporator and reducing the system failure rate. At the same time, the gas-liquid separator's design for liquid-gas separation of refrigerant in the defrost circuit effectively prevents refrigerant leakage caused by liquid slugging, improving the safety factor of system operation. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the refrigeration system in this invention.

[0013] Explanation of reference numerals in the attached figures: 1. First-stage compressor; 2. First-stage condenser; 3. First-stage expansion valve; 4. First-stage evaporator; 5. Second-stage compressor; 6. Second-stage condenser; 7. Second-stage expansion valve; 8. Second-stage evaporator; 9. Third-stage condenser; 10. Third-stage expansion valve; 11. Gas-liquid separator; 12. Third-stage evaporator. Detailed Implementation

[0014] The following will be combined with the appendix Figure 1 The technical solutions in the embodiments of the present invention have been clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0015] A single-unit dual-system hot fluorine defrosting refrigeration system includes a main refrigeration system, a secondary refrigeration system, and two gas-liquid separators 11. The main refrigeration system includes a first-stage compressor 1, a first-stage condenser 2, a first-stage expansion valve 3, and a first-stage evaporator 4. The first-stage compressor 1, the first-stage condenser 2, the first-stage expansion valve 3, and the first-stage evaporator 4 are connected in series to form a closed-loop refrigeration main circulation path. Two gas-liquid separators 11 are connected in parallel to the main refrigeration system and the auxiliary refrigeration system via solenoid valve A, respectively. The two gas-liquid separators 11 are respectively located at the outlet of the first-stage evaporator 4 and the outlet of the third-stage evaporator 12. It should be noted that the gas-liquid separator 11 ensures the separation of the gas and liquid phases, ensuring that the liquid refrigerant does not directly enter the compressor, thus preventing liquid slugging; The auxiliary refrigeration system includes a two-stage compressor 5, a two-stage condenser 6, a two-stage expansion valve 7, a two-stage evaporator 8, a three-stage condenser 9, a three-stage expansion valve 10, and a three-stage evaporator 12; Among them, the third-stage condenser 9 is connected in parallel with the second-stage condenser 6, and the second-stage compressor 5 is connected to the input terminals of the second-stage condenser 6 and the third-stage condenser 9 through a three-way valve A. The flow direction of the refrigerant output from the second-stage compressor 5 is switched through the three-way valve A. The output terminals of the secondary condenser 6 and the tertiary condenser 9 are connected to the secondary expansion valve 7 and the tertiary expansion valve 10 through the three-way valve B. The flow direction of the refrigerant output from the secondary condenser 6 and the tertiary condenser 9 is switched through the three-way valve B. The secondary expansion valve 7 is connected in series with the secondary evaporator 8, the tertiary expansion valve 10 is connected in series with the tertiary evaporator 12, and the tertiary evaporator 12 is connected in parallel to the main refrigeration system through the solenoid valve B and is located after the primary condenser 2. The secondary compressor 5, the tertiary condenser 9, the tertiary expansion valve 10, and the tertiary evaporator 12 are connected in series to form an auxiliary subcooling path; The secondary compressor 5, secondary condenser 6, secondary expansion valve 7, and secondary evaporator 8 are connected in series to form a closed-loop refrigeration secondary circulation path. The secondary compressor 5 is connected in series with the primary evaporator 4 and the tertiary evaporator 12 through the defrost solenoid valve pipeline to form a defrost path. It should be noted that when the system receives a cooling command, the main cooling system is in normal operation, while the auxiliary cooling system switches to the auxiliary subcooling path through three-way valve A and three-way valve B. Specifically, the refrigerant is compressed by the second-stage compressor 5 to form a high-temperature, high-pressure gas, which is then transported to the third-stage condenser 9 through the three-way valve A to condense it into a liquid state. The liquid refrigerant is then transported to the third-stage expansion valve 10 through the three-way valve B for throttling. The throttled refrigerant is then transported to the third-stage evaporator 12 through the solenoid valve. The cooling effect is achieved through the phase change heat absorption of the refrigerant at low temperature and low pressure. At this time, the third-stage evaporator 12 acts as a subcooler. The gaseous refrigerant discharged from the third-stage evaporator 12 returns to the second-stage compressor 5 through the solenoid valve C to achieve continuous auxiliary subcooling. The first-stage compressor 1 compresses the refrigerant and sends it to the first-stage condenser 2 through interface A for condensation, and then to the third-stage evaporator 12 through interface B. The third-stage evaporator 12 acts as a subcooler, subcooling the liquid refrigerant at the outlet of the first-stage condenser 2 through heat exchange, reducing flash gas after throttling, thereby increasing the unit cooling capacity, reducing the heat load of the main refrigeration system, reducing the energy consumption of the main refrigeration system, and achieving the energy-saving effect of "2+1>3", that is, the overall efficiency of the system is greater than the sum of the efficiencies of individual components. The subcooled refrigerant is sent to the first-stage expansion valve 3 through interface B for throttling, and the throttled refrigerant is evaporated through the first-stage evaporator 4. Finally, it returns to the first-stage compressor 1 through interface D, realizing a closed-loop refrigeration cycle. When the system receives a defrost command, the main refrigeration system will stop working, and the auxiliary refrigeration system will start the defrost mode. At this time, the auxiliary refrigeration system will switch to the defrost path through three-way valve A and three-way valve B. The second-stage compressor 5 compresses the refrigerant and delivers it to the second-stage condenser 6 for condensation via three-way valve A. The condensed refrigerant is then delivered to the second-stage expansion valve 7 for throttling via three-way valve B. The throttled refrigerant evaporates through the second-stage evaporator 8, and the gaseous refrigerant returns to the second-stage compressor 5 via solenoid valve C. The defrost solenoid valve tube is opened, and the high-temperature, high-pressure gas discharged from the second-stage compressor 5 enters the first-stage evaporator 4 and the third-stage evaporator 12 through the defrost solenoid valve tube, directly melting the frost layer on the surfaces of the first-stage evaporator 4 and the third-stage evaporator 12. This achieves efficient defrosting using the hot refrigerant from the auxiliary refrigeration system. The auxiliary defrosting mode is not only highly efficient and energy-saving, but also protects the integrity of the system. It allows the system to continuously refrigerate while simultaneously assisting in defrosting the main refrigeration system, improving the overall stability and reliability of the system. During the defrosting process, the solenoid valve B is opened to deliver hot fluorine mixed with liquid refrigerant to the gas-liquid separator 11. The gas-liquid separator 11 separates the liquid refrigerant and the gaseous refrigerant, ensuring that the liquid refrigerant does not directly enter the compressor and avoiding liquid slugging.

[0016] Furthermore, the connection point of the three-stage expansion valve 10 is located between the two-stage condenser 6 and the three-stage evaporator 12, realizing independent expansion control of the auxiliary subcooling path; It should be noted that the three-stage expansion valve 10 regulates the flow and pressure of the refrigerant delivered by the two-stage condenser 6, thereby reducing the pressure and temperature of the refrigerant and providing a more effective cooling effect.

[0017] Furthermore, the three-stage expansion valve 10 and the two-stage expansion valve 7 are connected in series via a three-way valve B; It should be noted that the refrigerant flow direction is controlled by the three-way valve B, which in turn controls the mode switching of the auxiliary refrigeration system. When the three-way valve B controls the refrigerant flow to the secondary expansion valve 7, the defrosting mode of the auxiliary refrigeration system is activated; when the three-way valve B controls the refrigerant flow to the tertiary expansion valve 10, the auxiliary refrigeration mode of the auxiliary refrigeration system is activated.

[0018] Furthermore, the third-stage evaporator 12 is connected before the second-stage compressor 5 via a solenoid valve C. The second-stage compressor 5 and the third-stage evaporator 12 can be dynamically switched via the solenoid valve C to adapt to different operating conditions. It should be noted that when the auxiliary refrigeration system is in defrost mode, the solenoid valve C is opened to connect the secondary compressor 5 and the tertiary evaporator 12. The gaseous refrigerant produced by the evaporation of the tertiary evaporator 12 flows back to the secondary compressor 5 through the solenoid valve C.

[0019] Based on the explanations and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and alterations to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A single unit dual system hot gas defrost refrigeration system as set forth in claim 1, characterized in that: The three-stage evaporator (12) is connected before the two-stage compressor (5) through the electromagnetic valve C, and the two-stage compressor (5) and the three-stage evaporator (12) realize dynamic switching through the electromagnetic valve C, and adapt to different working condition requirements.

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