REFRIGERATION SYSTEM

Description

FOREIGN PRIORITY

This application claims the benefit of Chinese Patent Application No. 202410141312.8, filed Jan. 31, 2024, and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of which in its entirety are herein incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to the technical field of refrigeration, and in particular to a refrigeration system.

BACKGROUND

In a refrigeration system, after a refrigerant flows through a compressor, the refrigerant is in a state of high temperature and high pressure, and when discharged, the refrigerant is at a high flow rate and a high temperature. A lubricating oil in the compressor is inevitably mixed and discharged with a refrigerant gas in a form of oil vapor or particles under an influence of high temperature. In the prior art, an oil separator is provided on an output side of the compressor to separate the lubricating oil from the refrigerant gas.

However, in the prior art, in some refrigeration systems, a temperature on an evaporator side can reach about 60° C., and a temperature on a condenser side can reach 90° C. or more. According to a design of the current oil separator system, high temperature and high pressure cause a large amount of refrigerant to be dissolved in the lubricating oil, resulting in a decrease in viscosity of the lubricating oil, which may lead to aggravated wear of equipment components in the compressor, shorten their service life, and even cause damage to components such as bearings in the compressor.

SUMMARY OF THE INVENTION

In view of the above problems, the present application provides a refrigeration system, which can improve a viscosity of oil, improve a lubrication effect and a service life of equipment such as a compressor while achieving efficient oil-gas separation.

The technical solution of the present application provides a refrigeration system. The refrigeration system includes a compressor, an oil separator, and an evaporator. The oil separator includes an inlet in communication with an outlet of the compressor and includes a refrigerant gas outlet and a mixture outlet. The evaporator includes an inlet in communication with the refrigerant gas outlet of the oil separator and an outlet in communication with an inlet of the compressor. The refrigeration system further includes a degasser, an input pipeline, and a first output pipeline, in which the degasser is in communication with the mixture outlet of the oil separator through the input pipeline, and is in communication with the inlet of the compressor through the first output pipeline.

Optionally, in the technical solution of the present application, the input pipeline is provided with a first throttle valve, and the first output pipeline is provided with a second throttle valve.

Optionally, in the technical solution of the present application, the degasser includes a degassing vessel and a heater provided in the degassing vessel.

Optionally, in the technical solution of the present application, the refrigeration system further includes a second output pipeline, one end of the second output pipeline is connected to a bottom portion of the degassing vessel, and the other end of the second output pipeline is connected to a downstream device.

Optionally, in the technical solution of the present application, the first throttle valve adjusts a flow rate in the input pipeline, and the second throttle valve adjusts a flow rate in the first output pipeline, such that a pressure in the degassing vessel is greater than a pressure in the first output pipeline.

Optionally, in the technical solution of the present application, the first throttle valve adjusts the flow rate in the input pipeline, and the second throttle valve adjusts the flow rate in the first output pipeline, such that a pressure P_m in the degassing vessel, a pressure P_s in the first output pipeline, and a pressure P_d in the input pipeline satisfy the following relationship: P_m=P_s+n*(P_d−P_s), where n∈[0.1, 0.5].

Optionally, in the technical solution of the present application, the degasser further includes an oil level sensor provided in the degassing vessel, a pressure sensor that measures a pressure in the degassing vessel, and a temperature sensor that measures an oil temperature in the degassing vessel.

Optionally, in the technical solution of the present application, the first output pipeline is connected to the outlet of the evaporator.

Optionally, in the technical solution of the present application, the first throttle valve and the second throttle valve operate in response to any detection result of the oil level sensor, the pressure sensor, and the temperature sensor.

In the technical solution of the present application, the compressor in the refrigeration system discharges a refrigerant mixed with a lubricating oil, and an oil and refrigerant mixture separated by the oil separator enters the degasser for degassing. A refrigerant gas obtained by re-separating and degassing in the degasser and a refrigerant gas separated in the oil separator finally enter the evaporator in the same way, and then are sucked into the compressor again for compression. During a circulation of the refrigerant in the above refrigeration system, the degasser separates the refrigerant in the oil and refrigerant mixture, reduces content of the refrigerant in the lubricating oil and increases a viscosity of the lubricating oil, thereby effectively improving a lubricating effect, reducing wear in an operation of the compressor, and extending a service life of the compressor. More importantly, the oil and refrigerant mixture is at a high temperature and a high pressure before entering a condenser, and thus a temperature of the refrigerant separated in the degasser is high, and the temperature of the refrigerant that is returned to the inlet of the compressor/the outlet of the evaporator is higher than the temperature of the refrigerant coming out of the evaporator. As a result, the temperature of the refrigerant at the inlet of the compressor/the outlet of the evaporator is generally higher, increasing degree of superheat and preventing the refrigerant from entering the compressor in a liquid state due to insufficient degree of superheat, thereby avoiding liquid slugging.

DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a schematic diagram of a refrigeration system;

FIG. 2 is a diagram of a refrigeration system in the prior art;

FIG. 3 is a diagram of a refrigeration system according to one or more embodiments of the present disclosure; and

FIG. 4 is a connection diagram of a degasser according to one or more embodiments of the present disclosure.

LIST OF REFERENCE NUMERALS

100—refrigeration system, 101—compressor, 102—condenser, 103—expansion valve, 104—evaporator, 105—oil separator, 1—degasser, 10—degassing vessel, 11—heater, 12—oil level sensor, 13—pressure sensor, 14—temperature sensor, 2—input pipeline, 3—first output pipeline, 4—first throttle valve, 5—second throttle valve, 6—second output pipeline, compressor inlet A1, compressor outlet A2, compressor lubricating oil inlet A3, evaporator inlet B1, evaporator outlet B2, oil separator inlet C1, oil separator refrigerant gas outlet C2, oil separator mixture outlet C3.

DETAILED DESCRIPTION

First, it should be noted that compositions, working principles, characteristics, advantages, and the like of a refrigeration system according to the present application will be described below in an illustrative manner. However, it should be understood that all descriptions are given for illustrative purposes only and therefore should not be construed as any limitation to the present application.

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

FIG. 1 is a schematic diagram of a refrigeration system.

As illustrated in FIG. 1, a refrigeration system 100 includes a compressor 101, a condenser 102, an expansion valve 103, and an evaporator 104, which are connected in sequence.

In a refrigeration/thermal cycle of the refrigeration system 100, a compression step is first performed, in which the compressor 101 sucks a refrigerant gas in the evaporator 104, and compresses and increases a pressure to obtain a high-temperature and high-pressure refrigerant gas.

Then, a condensation step is performed, in which the high-pressure and high-temperature refrigerant gas input in the compressor 101 is heat exchanged in the condenser 102, so that a temperature of cooling water in the condenser 102 is increased, and at the same time, the refrigerant gas is condensed into a refrigerant liquid.

Next, an expansion step is performed, in which the high-temperature and high-pressure refrigerant liquid in the condenser 102 flows through the expansion valve 103 for throttling expansion, so that the pressure and temperature thereof are reduced.

Finally, an evaporation step is performed, in which the evaporator 104 evaporates the low-pressure and low-temperature refrigerant liquid into a gas, and at the same time reduces a temperature of a heat exchange medium in the evaporator 104, achieving a refrigeration effect. The refrigerant gas in the evaporator 104 is sucked by the compressor 101 again for compression, and the above cycle of compression, condensation, throttling, and evaporation is repeated.

The compressor 101 in the refrigeration system 100 is configured as a screw compressor. A working principle of the screw compressor is that a driving rotor drives a driven rotor to rotate at a high speed, the rotors do not contact each other during a meshing process, and a pair of screws with a certain gap rotate at a high speed, achieving a purpose of sealing and compressing gas. Further, it is usually necessary to spray a lubricating oil between the screws, and the lubricating oil forms an oil film between the rotors, which plays a role in sealing, lubrication, and cooling.

When the refrigerant gas is compressed in the compressor 101, the refrigerant gas contacts the lubricating oil sprayed in the compressor 101, and at this time, the refrigerant gas is compressed to a high-temperature and high-pressure state, and the lubricating oil in the compressor 101 is inevitably mixed and discharged with the refrigerant gas in a form of oil vapor or particles under an influence of high temperature. When the refrigerant gas mixed with oil is subjected to a subsequent refrigeration cycle, the oil in the refrigerant gas adheres to various portions of a pipeline of the refrigeration cycle, which affects an overall heat exchange efficiency of the refrigeration system 100. Further, as the lubricating oil in the compressor 101 is continuously discharged along with the refrigerant gas, lubricating effects between components such as the screws and bearings in the compressor 101 are also affected, resulting in an increase in frictional collision between the components such as the screws and the bearings in the compressor 101, and reducing the working efficiency and service life of the compressor 101.

FIG. 2 is a diagram of a refrigeration system in the prior art.

As illustrated in FIG. 2, in the prior art, the lubricating oil mixed in the refrigerant gas is separated by providing an oil separator 105 on an output side of the compressor 101. The refrigerant gas separated from the oil separator 105 flows to the condenser 102, the expansion valve 103, and the evaporator 104, and the refrigeration cycle of the refrigeration system 100 continues. The separated lubricating oil in the oil separator 105 is returned to the compressor 101 for lubrication. In FIG. 2, the solid line is a refrigerant flow path, and the dashed line is an oil and refrigerant mixture/lubricating oil flow path.

However, in the above technical solution in the prior art, it is inevitable that a small amount of lubricating oil is contained in the refrigerant gas separated in the oil separator 105. Further, a temperature of the lubricating oil separated from the oil separator 105 is relatively high. Since a viscosity of the lubricating oil decreases with an increase of temperature, the lubricating oil having too low viscosity causes insufficient lubrication, and frictions between the components such as the screws and the bearings in the compressor 101 are increased, which is not conducive to a normal operation of the compressor 101.

According to the working principle of the refrigeration system 100 and the problems faced in the refrigeration cycle thereof, one or more embodiments of the present application provides a refrigeration system 100.

FIG. 3 is a diagram of the refrigeration system 100 according to one or more embodiments of the present application.

As illustrated in FIG. 3, the refrigeration system 100 according to some embodiments includes a compressor 101, an oil separator 105, and an evaporator 104. The compressor 101 is provided with an inlet A1 and an outlet A2; the evaporator 104 is provided with an inlet B1 and an outlet B2; and the oil separator 105 is provided with an inlet C1, a refrigerant gas outlet C2, and a mixture outlet C3.

The inlet A1 of the compressor 101 is in communication with the outlet B2 of the evaporator 104, and the outlet A2 of the compressor 101 is in communication with the inlet C1 of the oil separator 105. The inlet B1 of the evaporator 104 is indirectly in communication with the refrigerant gas outlet C2 of the oil separator 105.

The oil separator 105 has the inlet C1 that is in communication with the outlet A2 of the compressor 101, receives a high-temperature and high-pressure refrigerant gas mixed with a lubricating oil discharged from the compressor 101, and performs oil-gas separation on the refrigerant gas. The refrigerant gas outlet C2 of the oil separator 105 returns the separated refrigerant gas to the cycle of the refrigeration system 100, and the separated refrigerant gas can sequentially flow through the condenser 102, the expansion valve 103, and the evaporator 104. The mixture outlet C3 of the oil separator 105 is used to discharge the separated oil and refrigerant mixture.

FIG. 4 is a connection diagram of a degasser according to one or more embodiments of the present application.

As illustrated in FIG. 3 and FIG. 4, the refrigeration system 100 further includes a degasser 1, an input pipeline 2, and a first output pipeline 3. The degasser 1 is used to separate the oil and refrigerant mixture. The input pipeline 2 communicates with the mixture outlet C3 of the oil separator 105 and the degasser 1, and is used to input the oil and refrigerant mixture into the degasser 1. The first output pipeline 3 communicates with the degasser 1 and the inlet A1 of the compressor 101/the outlet B2 of the evaporator 104, and is used to output the refrigerant gas obtained through degassing in the degasser 1.

In some embodiments of the present application, the outlet A2 of the compressor 101 discharges the refrigerant gas mixed with lubricating oil, which is first separated into a refrigerant gas and an oil and refrigerant mixture by the oil separator 105, and the refrigerant gas returns to the refrigeration system 100 to continue circulating, and the oil and refrigerant mixture enters the degasser 1 through the input pipeline 2 for degassing. The refrigerant gas separated by the degasser 1 returns to the inlet A1 of the compressor 101/the outlet B2 of the evaporator 104 through the first output pipeline 3, and then is sucked in by the compressor 101 again for compression. During a circulation of the refrigerant gas in the refrigeration system 100, the degasser 1 separates a refrigerant in the oil and refrigerant mixture, reduces content of the refrigerant in the lubricating oil, and can increase the viscosity of the lubricating oil, thereby effectively improving the lubricating effect, reducing the wear of the compressor 101 during operation, and extending the service life of the compressor 101. More importantly, the oil and refrigerant mixture is at a high temperature and a high pressure before entering the condenser 102, and thus a temperature of the refrigerant separated in the degasser 1 is high, and the temperature of the refrigerant that is returned to the inlet A1 of the compressor 101/the outlet B2 of the evaporator 104 is higher than the temperature of the refrigerant coming out of the evaporator 104. As a result, the temperature of the refrigerant at the inlet A1 of the compressor 101/the outlet B2 of the evaporator 104 is generally higher, increasing degree of superheat and preventing the refrigerant from entering the compressor 101 in a liquid state due to insufficient degree of superheat, thereby avoiding liquid slugging.

Referring to FIG. 4, in some embodiments of the present application, the degasser 1 includes a degassing vessel 10 and a heater 11 provided in the degassing vessel 10. The degassing vessel 10 contains a refrigerant gas, a lubricating oil, and an oil and refrigerant mixture, and the heater 11 is disposed at bottom portion of the degassing vessel 10 and heats the oil and refrigerant mixture. The input pipeline 2 is connected to the degassing vessel 10 from one end of an upper side surface of the degassing vessel 10 and inputs the oil and refrigerant mixture into the degassing vessel 10. The first output pipeline 3 is connected to the degassing vessel 10 from the other end of the upper side surface of the degassing vessel 10 and discharges the refrigerant gas from the degassing vessel 10.

In some embodiments, the refrigeration system 100 further includes a first throttle valve 4 and a second throttle valve 5, the first throttle valve 4 is provided on the input pipeline 2, and the second throttle valve 5 is provided on the first output pipeline 3.

When the degasser 1 performs degassing, a high-temperature and high-pressure oil and refrigerant mixture is discharged from the mixture outlet C3 of the oil separator 105, and flows into the degasser 1 through the input pipeline 2. The first throttle valve 4 on the input pipeline 2 throttles the high-temperature and high-pressure oil and refrigerant mixture, the high-temperature and high-pressure oil and refrigerant mixture undergoes decompression expansion, a part of the refrigerant gas in the oil and refrigerant mixture escapes into the degassing vessel 10, the first output pipeline 3 discharges the degassing vessel 10, and the remaining liquid oil and refrigerant mixture in a liquid state flows into the bottom portion of the degassing vessel 10 along the input pipeline 2. The heater 11 in the bottom portion of the degassing vessel 10 heats the liquid oil and refrigerant mixture and vaporizes the refrigerant in the liquid oil and refrigerant mixture, and the obtained refrigerant gas is also discharged from the degassing vessel 10 through the first output pipeline 3.

Optionally, in some embodiments of the present application, the first throttle valve 4 can adjust a flow rate of the oil and refrigerant mixture in the input pipeline 2, and the second throttle valve 5 can adjust a flow rate of the refrigerant gas in the first output pipeline 3. In other words, the first throttle valve 4 and the second throttle valve 5 can adjust a gas inlet flow rate and a gas outlet flow rate of the degasser 1, respectively, thereby adjusting a gas amount and a gas pressure in the degasser 1. Specifically, by adjusting the first throttle valve 4 and the second throttle valve 5, the gas inlet flow rate of the degasser 1 is greater than the gas outlet flow rate, an amount of gas in the degasser 1 gradually increases, and similarly, a gas pressure P_m in the degasser 1 also gradually increases. Conversely, by adjusting the first throttle valve 4 and the second throttle valve 5, the gas inlet flow rate of the degasser 1 is less than the gas outlet flow rate, the amount of gas in the degasser 1 gradually decreases, and similarly, the gas pressure P_m in the degasser 1 also gradually decreases.

In some embodiments of the present application, the degasser 1 combines throttling and depressurization with heating and vaporization, so that most of the refrigerant in the oil and refrigerant mixture can be degassed and discharged. In addition, the above-mentioned degasser 1 has low cost, simple structure, and is easy to be miniaturized, and can be applied to various refrigeration systems for oil-gas separation.

In practical applications of the present application, the first throttle valve 4 and the second throttle valve 5 may be provided as a capillary tube, a thermal expansion valve, an electronic expansion valve, or the like, without limitation.

Referring to FIG. 4, in some embodiments of the present application, the refrigeration system 100 further includes a second output pipeline 6. One end of the second output pipeline 6 is connected to the bottom portion of the degassing vessel 10, the other end of the second output pipeline 6 is connected to the lubricating oil inlet A3 of the compressor 101, and the second output pipeline 6 returns the lubricating oil separated by the degasser 1 to the compressor 101.

In some embodiments of the present application, most of the refrigerant in the oil and refrigerant mixture can be degassed and discharged by combining throttling and depressurization with heating and vaporization, and the discharged lubricating oil is cooled, thereby obtaining a lubricating oil having low impurity and high viscosity and returning the lubricating oil to the compressor 101.

Optionally, in some embodiments of the present application, the degasser 1 further includes one or more oil level sensors 12, a pressure sensor 13, and a temperature sensor 14 provided in the degassing vessel 10. The first throttle valve 4 and the second throttle valve 5 operate in response to any detection result of the oil level sensor 12, the pressure sensor 13, and the temperature sensor 14.

The oil level sensor 12 detects a liquid level of the liquid oil and refrigerant mixture (illustrated by the dotted line in FIG. 4) in the degassing vessel 10 such that the liquid level of the liquid oil and refrigerant mixture does not exceed or maintain a preset level of the oil level sensor 12. In the degassing vessel 10, a volume of a portion below the liquid level of the liquid oil and refrigerant mixture is a current liquid volume of the degassing vessel 10, and a volume of a portion above the liquid level is a current gas volume of the degassing vessel 10. Therefore, the liquid volume and gas volume currently contained in the degassing vessel 10 can be controlled by providing the oil level sensor 12 and detecting the liquid level.

The first throttle valve 4 and the second throttle valve 5 can operate in response to a detection result of the oil level sensor 12, for example, when the oil level sensor 12 detects that the liquid level of the liquid oil and refrigerant mixture in the degassing vessel 10 is higher than the preset level of the oil level sensor 12, a flow rate of the first throttle valve 4 may be reduced and/or a flow rate of the second throttle valve 5 may be increased to reduce the liquid oil and refrigerant mixture in the degassing vessel 10.

Optionally, the preset level of the oil level sensor 12 is lower than that of the input pipeline 2, and thus an outlet of the input pipeline 2 is prevented from being submerged by the liquid oil and refrigerant mixture, and the refrigerant gas expanded and separated in the input pipeline 2 is directly discharged from the first output pipeline 3.

The pressure sensor 13 measures and feeds back a pressure in the degassing vessel 10, and the first throttle valve 4 and the second throttle valve 5 can operate in response to the detection result of the oil level sensor 12 to stabilize the pressure P_m in the degassing vessel within a fixed value or a fixed range. For example, when the pressure P_m in the degassing vessel 10 is lower than a preset pressure of the pressure sensor 13, the flow rate of the first throttle valve 4 may be increased and/or the flow rate of the second throttle valve 5 may be decreased to increase an amount of gas in the degassing vessel 10 and the pressure P_m in the degassing vessel 10.

Optionally, in some embodiments of the present application, by adjusting the first throttle valve 4 and the second throttle valve 5, the pressure P_m in the degassing vessel 10, the pressure P_s in the first output pipeline 3, and the pressure P_d in the input pipeline 2 satisfy the following relationship, P_m=P_s+n*(P_d−P_s), where n∈[0.1, 0.5], to ensure a stable circulation in the entire degasser 1.

The temperature sensor 14 measures and feeds back an oil temperature in the degassing vessel 10, and the heater 11 can operate in response to a detection result of the temperature sensor 14 to stabilize the oil temperature in the degassing vessel 10 within a fixed value or a fixed range. For example, when the oil temperature in the degassing vessel is lower than a preset temperature of the temperature sensor 14, the heating efficiency of the heater 11 may be increased to increase the oil temperature in the degassing vessel 10.

Optionally, in some embodiments of the present application, the heater 11 is adjusted in response to the detection result of the temperature sensor 14, and thus the oil temperature in the degassing vessel 10 is maintained at 40 to 60 K.

Optionally, in some embodiments of the present application, the degasser 1 may further adjust the first throttle valve 4, the second throttle valve 5, and the heater 11 by integrating detection results of the oil level sensor 12, the pressure sensor 13, and the temperature sensor 14, to ensure a stable circulation in the entire degasser 1.

The technical solutions of the present disclosure have been described with reference to the accompanying drawings. However, it is easily understood by those skilled in the art that the protection scope of the present disclosure is obviously not limited to the above specific embodiments. Those skilled in the art can make equivalent changes or substitutions to relevant technical features without departing from the principle of the present disclosure, and all technical solutions after these changes or substitutions will fall within the protection scope of the present disclosure.