REFRIGERATION SYSTEM

Description

PRIORITY CLAIM

This application claims benefit of Chinese Patent Application No. 202411030150.7, filed Jul. 29, 2024, and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of which in their entirety are herein incorporated.

BACKGROUND

This application relates to the technical field of refrigeration, specifically to a refrigeration system, and particularly to a refrigeration system that reduces a refrigerant charge amount and improves performance of an oil separator by setting a regenerator.

SUMMARY

An object of this application is to provide a refrigeration system to at least resolve or alleviate some of problems that exist in the related art.

This application provides a refrigeration system including: a compressor, a condenser, an expansion valve, and an evaporator connected in sequence by a refrigerant pipeline; a regenerator with an inlet on a primary side connected to an outlet of the condenser, an outlet on the primary side connected to an inlet of the expansion valve, an inlet on a secondary side connected to an outlet of the evaporator, and an outlet of the secondary side connected to an inlet of the compressor; and a refrigerant gas delivery pump disposed in a pipeline connecting the inlet on the secondary side of the regenerator and the outlet of the evaporator.

In one or more embodiments, the refrigeration system further includes an oil separator disposed in a refrigerant pipeline connecting an outlet of the compressor and an inlet of the condenser, or disposed inside the condenser.

In one or more embodiments, the regenerator is a plate heat exchanger.

In one or more embodiments, a flow rate of a refrigerant gas flowing through the refrigerant gas delivery pump accounts for 50% or less of a total flow rate of the refrigerant gas at the inlet of the compressor.

In one or more embodiments, the flow rate of the refrigerant gas flowing through the refrigerant gas delivery pump accounts for 15% to 30% of the total flow rate of the refrigerant gas at the inlet of the compressor.

In one or more embodiments, the evaporator includes a first evaporator outlet and a second evaporator outlet, the inlet of the compressor is connected to the first evaporator outlet, and the inlet on the secondary side of the regenerator is connected to the second evaporator outlet.

In one or more embodiments, a refrigerant with which the refrigerant pipeline is filled is a low GWP refrigerant selected from any one of R515B, R513A, or R1234ze.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of a refrigeration system according to one or more embodiments of this application.

FIG. 2 is a schematic structural diagram of the refrigeration system according to one or more embodiments of this application.

FIG. 3 is a schematic structural diagram of a refrigeration system including an oil separator disposed in a condenser according to one or more embodiments of this application.

FIG. 4 is a schematic structural diagram of a refrigeration system including an external oil separator according to one or more embodiments of this application.

Reference numerals: compressor 1, condenser 2, expansion valve 3, evaporator 4, first evaporator outlet 41, second evaporator outlet 42, regenerator 5, refrigerant pipeline 6, evaporator outlet first pipeline 61, evaporator outlet second pipeline 62, evaporator inlet refrigerant pipeline 63, condenser outlet refrigerant pipeline 64, refrigerant gas delivery pump 7, oil separator 8(a), oil separator 8(b).

DETAILED DESCRIPTION OF THE DISCLOSURE

It should be noted that working principles, features, advantages, and the like of a refrigeration apparatus according to this application will be explained below by way of embodiments. However, it should be understood that all descriptions are only given for exemplification and therefore these embodiments should not be understood as forming any limitation on this application.

In addition, for any single technical feature described or implicit in some embodiments mentioned herein, or any single technical feature illustrated or implicit in the drawings, this application still allows any combination or deletion between these technical features (or equivalents thereof) without any technical obstacles, thereby obtaining more other embodiments of this application that may not be directly mentioned herein.

Note that a “primary side” described in this application refers to a side of a heat exchanger with a higher temperature, that is, a heat release side, and a “secondary side” described in this application refers to a side of the heat exchanger with a lower temperature, that is, a heat absorption side.

Compared with a traditional refrigerant, low global warming potential (GWP) refrigerants have lower global warming potential and less impact on climate warming, and most low GWP refrigerants have no destructive effect on the ozone layer.

In consideration of an impact of the traditional refrigerant on the environment, a use of the low GWP refrigerants, which are more environmentally friendly, has gradually become a preferred solution for a refrigeration system, and the refrigeration industry is promoted to develop in a greener and more sustainable direction. However, compared with the traditional refrigerant, the low GWP refrigerants are usually more expensive, which increases initial investment costs of the refrigeration system.

Refrigeration systems using a low GWP refrigerant such as HFO, refrigerants mixed with HFO, superheat of the refrigerant at an exhaust port of a compressor is lower than that of a traditional high GWP refrigerant. When the superheat of the refrigerant is very low, performance of an oil separator is greatly affected, thereby causing a lubricating oil to escape into a heat exchanger, so that heat exchange performance of the heat exchanger is affected. At the same time, a flooded condenser in the related art always requires a large refrigerant charge amount to achieve a certain degree of subcooling, so that costs are high.

The refrigeration system of the present disclosure resolves or alleviates some of these problems.

FIG. 1 is a schematic structural diagram of a refrigeration system according to one or more embodiments of this application. Referring to FIG. 1, the refrigeration system according to the one or more embodiments includes: a compressor 1, a condenser 2, an expansion valve 3, an evaporator 4, a regenerator 5, and a refrigerant pipeline 6 connecting the compressor 1, the condenser 2, the expansion valve 3, and the evaporator 4 in sequence in a refrigerant flow direction. The refrigerant pipeline 6 locally includes an evaporator outlet first pipeline 61, an evaporator outlet second pipeline 62, an evaporator inlet refrigerant pipeline 63, a condenser outlet refrigerant pipeline 64, and a refrigerant gas delivery pump 7.

As shown in FIG. 1, the refrigerant pipeline 6 connects the compressor 1, the condenser 2, the regenerator 5, the expansion valve 3, and the evaporator 4 in sequence to form a circulation loop, and a flow direction of a refrigerant in the circulation loop is shown by an arrow in FIG. 1. The regenerator 5 includes a primary side and a secondary side, and an inlet on the primary side is connected to an outlet of the condenser 2, an outlet on the primary side is connected to an inlet of the expansion valve 3, an inlet on the secondary side is connected to an outlet of the evaporator 4, and an outlet on the secondary side is connected to an inlet of the compressor 1. A part of the refrigerant at the outlet of the evaporator 4 flows into the compressor 1 through the evaporator outlet first pipeline 61, and a part thereof flows into the secondary side of the regenerator 5 through the evaporator outlet second pipeline 62, and exchanges heat with the high-temperature and high-pressure refrigerant flowing out of the condenser 2 on the primary side of the regenerator 5, thereby absorbing heat and increasing a temperature. The refrigerant gas delivery pump 7 is also provided on the pipeline connecting the inlet on the secondary side of the regenerator 5 and the outlet of the evaporator 4, that is, the evaporator outlet second pipeline 62.

In the refrigeration system according to some embodiments of this application described above, the refrigerant is compressed into a high-temperature and high-pressure refrigerant gas in the compressor 1, and then the high-temperature and high-pressure refrigerant gas is delivered to the condenser 2 through the refrigerant pipeline 6. The high-temperature and high-pressure refrigerant gas exchanges heat with an external medium, such as water or air, in the condenser 2. After the temperature and pressure are reduced and the high-temperature and high-pressure refrigerant gas is condensed into a medium-temperature and high-pressure refrigerant liquid, this refrigerant liquid is delivered to the primary side of the regenerator 5 through the condenser outlet refrigerant pipeline 64, and exchanges heat with a refrigerant flowing through the secondary side of the regenerator 5, so that the refrigerant in the primary side is cooled to required subcooling, such as 5K subcooling, thereby ensuring that the refrigerant is completely condensed into a liquid when flowing out of the primary side of the regenerator 5, and a heat exchange efficiency of the evaporator 4 is improved.

The refrigerant liquid cooled by the regenerator 5 rapidly reduces a pressure when passing through the expansion valve 3, and is delivered to the evaporator 4 through the evaporator inlet pipe 63. The low-temperature and low-pressure refrigerant liquid exchanges heat with the outside in the evaporator 4 and evaporates into a low-temperature and low-pressure refrigerant gas. In this case, due to a heat exchange capacity or a heat exchange efficiency of the evaporator 4, or refrigerant working conditions, it is possible that the refrigerant at the outlet of the evaporator 4 does not reach a full saturation state, the superheat is low, and some liquid droplets may still be entrained in the refrigerant gas. In this case, after the low-temperature and low-pressure refrigerant gas flows out of the outlet of the evaporator 4, a part of the low-temperature and low-pressure refrigerant gas enters the evaporator outlet first pipeline 61, and the other part thereof enters the evaporator outlet second pipeline 62, and provides a driving force for the refrigerant gas discharged from the evaporator outlet second pipeline 62 through the refrigerant gas delivery pump 7, and thus the refrigerant gas discharged from the evaporator outlet second pipeline 62 is delivered to the secondary side of the regenerator 5, and exchanges heat with the medium-temperature and high-pressure refrigerant at the primary side of the regenerator 5, so that the low-temperature and low-pressure refrigerant in the secondary side further absorbs heat and increases the temperature. The refrigerant gas whose temperature is increased is delivered from the outlet on the secondary side of the regenerator 5 to the inlet of the compressor 1, and is mixed with the refrigerant from the evaporator outlet first pipeline 61 before entering the compressor 1, so that superheat of the overall refrigerant can be increased to required superheat, such as 5K superheat, and thus it is ensured that the refrigerant is completely evaporated into a gaseous state when entering the compressor 1, and problems such as liquid slugging caused by the refrigerant liquid entering the compressor 1 can be avoided.

In some embodiments, the medium-temperature and high-pressure refrigerant liquid at the outlet of the condenser 2 is controlled to exchange heat in the regenerator 5 with a part of the low-temperature and low-pressure refrigerant gas at the outlet of the evaporator 4, so that the refrigerant liquid is cooled to required subcooling, and the refrigerant gas is increased in the temperature to the required superheat, thereby avoiding problems in the related art, such as liquid slugging in the compressor 1 which may be caused by such a reason that the refrigerant at the inlet of the compressor 1 is not completely evaporated due to low superheat and the refrigerant gas is entrained with refrigerant droplets.

At the same time, by providing the regenerator 5 to further cool the refrigerant liquid at the outlet of the condenser 2, a heat exchange demand of the condenser 2 itself is reduced, that is, a refrigerant capacity of the condenser 2 can be appropriately reduced, so that a refrigerant charge amount of the overall refrigeration system can be reduced by 10% to 20%, and only about 5% of the refrigerant can achieve the subcooling of the flooded condenser 2, so that investment costs of the refrigeration system is reduced.

By providing the refrigerant gas delivery pump 7 on the evaporator outlet second pipeline 62, the driving force is provided for the refrigerant gas discharged from the evaporator outlet second pipeline 62 at the outlet of the evaporator, and a pressure of the refrigerant gas discharged from the evaporator outlet second pipeline 62 is increased, so that a problem that the refrigeration system has low efficiency because of a pressure drop generated when a part of the refrigerant gas passes through the regenerator 5 is resolved. By providing the refrigerant gas delivery pump 7, a control of a flow rate of the refrigerant flowing through the evaporator outlet second pipeline 62 can also be facilitated, so that the superheat of the refrigerant gas entering the inlet of the compressor 1 and the subcooling of the refrigerant flowing through the regenerator 5 can be appropriately adjusted.

Specifically, in some embodiments of this application, a flow rate of the refrigerant gas flowing through the refrigerant gas delivery pump 7 can account for 50% or less of a total flow rate of the refrigerant gas at the inlet of the compressor 1.

In some embodiments of this application, the flow rate of the refrigerant gas flowing through the refrigerant gas delivery pump can account for 15% to 30% of the total flow rate of the refrigerant gas at the inlet of the compressor 1.

According to some embodiments, the flow rate of the refrigerant gas flowing through the refrigerant gas delivery pump 7 is controlled to account for 50% or less of the total flow rate of the refrigerant gas at the inlet of the compressor 1, and the flow rate of the refrigerant gas flowing through the refrigerant gas delivery pump 7 preferably account for 15% to 30% of the total flow rate of the refrigerant gas at the inlet of the compressor 1. Accordingly, it is avoided that a large amount of refrigerant gas is delivered into the regenerator 5 through the refrigerant gas delivery pump 7 to exchange heat with the refrigerant liquid at the outlet of the condenser 2, which may cause excessive pressure drop and reduce the efficiency of the refrigeration system.

The refrigerant gas delivery pump 7 used in some embodiments of this application is preferably a low-lift pump, but this application is not limited thereto, and refrigerant gas delivery pumps of different working conditions are selected according to the pressure drop generated when the refrigerant gas discharged from the evaporator outlet second pipeline 62 passes through the regenerator 5, which is included in the protection scope of this application.

Although some embodiments are configured such that the refrigerant gas after the temperature rise is delivered from the outlet on the secondary side of the regenerator 5 to the inlet of the compressor 1 and is mixed with the refrigerant directly from the evaporator outlet first pipeline 61, this application is not limited thereto, and all configurations are included in the protection scope of this application as long as the superheat of the refrigerant gas entering the compressor 1 is increased, for example, the other end of the refrigerant pipeline 6 connected to the outlet of the secondary side of the regenerator 5 is connected to the evaporator outlet first pipeline 61.

Preferably, the refrigerant with which the refrigerant pipeline 6 is filled is a low GWP refrigerant selected from any one of R515B, R513A, or R1234ze.

In some embodiments, the regenerator 5 is a plate heat exchanger.

The plate heat exchanger includes a plurality of thin plates with a small gap, and has a larger heat exchange area as compared with other types of heat exchangers, and thus more efficient heat transfer can be achieved. At the same time, a structure of the plate heat exchanger is more compact, a space required for installation is smaller and the costs are lower. By using the plate heat exchanger to bear a part of the heat exchange demand in the condenser 2, a using amount of copper tubes used in the condenser 2 is also reduced.

Although the regenerator 5 preferably uses the plate heat exchanger in some embodiments, this application is not limited thereto, and other heat exchangers, such as MCHX, can also be used as long as the refrigerant liquid discharged from the condenser 2 and the refrigerant gas discharged from the evaporator 4 can complete the heat exchange in the regenerator 5, which is included in the protection scope of this application.

In addition, in some embodiments of this application, the refrigerant with which the refrigerant pipeline 6 is filled preferably uses the low GWP refrigerant selected from any one of R515B, R513A, or R1234ze, but this application is not limited thereto, and other low GWP refrigerants can also be used as the refrigerant, which is also included in the protection scope of this application.

Preferably, FIG. 2 is a schematic structural diagram of the refrigeration system according to one or more embodiments of this application. As shown in FIG. 2, the evaporator 4 includes a first evaporator outlet 41 and a second evaporator outlet 42, the inlet of the compressor 1 is connected to the first evaporator outlet 41, and the inlet on the secondary side of the regenerator 5 is connected to the second evaporator outlet 42.

According to some embodiments, one end of the evaporator outlet first pipeline 61 is connected to the first evaporator outlet 41, and the other end thereof is connected to the inlet of the compressor 1, so that a part of the refrigerant gas discharged from the evaporator 4 is directly delivered to the compressor 1. One end of the evaporator outlet second pipeline 62 is connected to the second evaporator outlet 42, and the other end thereof is connected to the inlet on the secondary side of the regenerator 5. When the refrigerant gas is discharged from the evaporator 4, the refrigerant gas is directly discharged through different outlets, so that it is avoided that the refrigerant gas discharged from the same outlet and then diverted through different pipelines may cause problems of a flow rate control, a pressure loss, and inconvenience of maintenance, and a possibility of generating a pressure drop when the refrigerant gas passes through a three-way component can also be reduced.

Similarly, the refrigerant gas whose temperature is increased on the secondary side of the regenerator 5 is delivered from the outlet on the secondary side of the regenerator 5 to the inlet of the compressor 1, and is mixed with the refrigerant from the evaporator outlet first pipeline 61 before entering the compressor 1, so that the superheat of the overall refrigerant entering the compressor 1 can be ensured.

FIG. 3 is a schematic structural diagram of a refrigeration system including an oil separator disposed in a condenser according to the one or more embodiments of this application. Referring to FIG. 3, the refrigeration system according to the one or more embodiments of this application includes: an oil separator 8(a).

As shown in FIG. 3, in the refrigeration system including the external oil separator according to some embodiments of this application, the oil separator 8(a) is disposed inside the condenser 2, and after the high-temperature and high-pressure refrigerant gas discharged by the compressor 1 enters the condenser 2, the high-temperature and high-pressure refrigerant gas first passes through the oil separator 8(a) to separate a lubricating oil in the refrigerant gas, and then completes the heat exchange in the condenser 2.

FIG. 4 is a schematic structural diagram of a refrigeration system including an external oil separator according to one or more embodiments of this application. Referring to FIG. 4, the refrigeration system according to one or more embodiments of this application includes an oil separator 8(b).

As shown in FIG. 4, in the refrigeration system including the external oil separator according to some embodiments of this application, the oil separator 8(b) is disposed on the pipeline between the outlet of the compressor 1 and the inlet of the condenser 2, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is delivered into the oil separator 8(b) to separate the lubricating oil entrained in the refrigerant gas, and the refrigerant gas separated from the lubricating oil is delivered through the refrigerant pipeline 6 into the condenser 2 to complete the heat exchange.

When the refrigeration system is operating normally, it is necessary to reduce friction or wear of the compressor 1 by using the lubricating oil to ensure the normal operation of the compressor 1. However, when the refrigerant gas passes through the compressor 1, a small amount of lubricating oil may be carried into the refrigerant pipeline 6. A heat transfer coefficient of the lubricating oil is low, and if the lubricating oil adheres to an inner wall of the pipeline, heat exchange efficiencies of the condenser 2 and the evaporator 4 may be affected. By providing the oil separator 8(a) or the oil separator 8(b), the lubricating oil entrained in the refrigerant gas is separated before entering the condenser 2, so that the lubricating oil can be prevented from entering the condenser 2 to affect a working efficiency of the condenser 2.

However, in the related art, when a low GWP refrigerant is used instead of a traditional refrigerant, if the superheat of the refrigerant gas discharged from the evaporator 4 is low, for example, if the superheat of the refrigerant gas is lower than 3K to 4K, there is a possibility that the refrigerant gas is likely to be entrained with some refrigerant droplets that have not been completely evaporated, and when these refrigerant droplets pass through the compressor 1, these refrigerant droplets may be easily mixed with the lubricating oil in the compressor 1, making it difficult to separate the lubricating oil from the refrigerant, and as a result, performance of the oil separator 8(a) or the oil separator 8(b) is reduced.

The regenerator 5 is provided in the refrigeration system, the inlet on the primary side of the regenerator 5 is connected to the outlet of the condenser 2, the outlet on the primary side of the regenerator 5 is connected to the inlet of the expansion valve 3, the inlet on the secondary side of the regenerator 5 is connected to the outlet of the evaporator 4, and the outlet on the secondary side of the regenerator 5 is connected to the inlet of the compressor 1, so that a part of the low-temperature and low-pressure refrigerant discharged from the evaporator 4 can exchange heat with the medium-temperature and high-pressure refrigerant discharged from the condenser 2 in the regenerator 5, and thus the part of the low-temperature and low-pressure refrigerant from the evaporator 4 can further absorb heat and increase the temperature and then is mixed with the refrigerant in the evaporator outlet first pipeline 61, thereby ensuring and improving the superheat of the refrigerant gas entering the compressor 1, for example, 5K superheat. In this case, the refrigerant gas aspirated by the compressor 1 is fully saturated and evaporated, avoiding a problem that some refrigerant droplets may not be completely vaporized due to the low superheat of the refrigerant gas at the inlet of the compressor 1 and merge with the lubricating oil, and as a result, the oil separator 8(a) or the oil separator 8(b) and the condenser 2 have low heat exchange performance.

It should be noted that in some embodiments of this application, there is no limitation on a model, working principles, and the like of the oil separator 8(a) or the oil separator 8(b), and a use of a rotary oil separator, a gravity oil separator, and the like according to requirements and operating conditions of different refrigeration systems is included in the protection scope of this application.

The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application shall be included in the protection scope of this application.