A two-stage refrigeration cycle system

Abstract

The application discloses a two-stage refrigeration cycle system, which comprises a first double-suction compressor, a condenser and a first gas-liquid separator connected in sequence to the exhaust port of the first double-suction compressor, a first capillary pipe connected to the gas outlet of the first gas-liquid separator, and an outlet of the first capillary pipe divided into two paths, one of which is provided with a first electromagnetic valve, and the other of which is provided with a second electromagnetic valve and a second gas-liquid separator in sequence, and the outlet of the first electromagnetic valve and the gas outlet of the second gas-liquid separator are combined into one path and then connected to the secondary suction port of the first double-suction compressor through a first pipeline. Through air supplement and enthalpy increase, the suction pressure of the compressor is improved, the circulating efficiency of the system is improved, and the refrigeration efficiency is ultimately improved.

Description

Technical Field

[0001] This invention relates to the field of refrigeration technology, and more specifically, to a two-stage refrigeration cycle system. Background Technology

[0002] Refrigerators, as refrigeration devices, are used to store food, ingredients, or other items. The refrigeration principle of a refrigerator involves the compressor compressing the refrigerant into a high-temperature, high-pressure gaseous state, which is then sent to the condenser where it is cooled into a high-temperature, high-pressure liquid refrigerant. The liquid refrigerant is then throttled and depressurized by a throttling device, becoming a low-temperature, low-pressure gas-liquid mixture (more liquid), which enters the evaporator to evaporate and revert to a gaseous state. It then returns to the compressor for further compression, and the cycle continues, refining the refrigeration process. Currently, compressors generally use single-inlet and single-outlet designs. Due to the limited suction and discharge pressures, the overall heat exchange efficiency of the system is often not fully utilized, resulting in lower refrigeration efficiency and slower cooling of the compartments. Refrigerators requiring higher refrigeration efficiency use dual-inlet compressors, which have one auxiliary suction port, one main suction port, and one discharge port. While dual-inlet compressors increase the refrigeration capacity, they suffer from uneven gas-liquid distribution in the auxiliary suction branch when the compressor is running at high speed and generating heat. This can lead to incomplete refrigerant evaporation, insufficient deep cooling, and low overall system refrigeration efficiency. Therefore, it is necessary to improve the existing technology. Summary of the Invention

[0003] The purpose of this invention is to provide a two-stage refrigeration cycle system, aiming to solve at least one of the technical problems existing in the prior art. To achieve the above objective, the technical solution adopted is as follows:

[0004] A two-stage refrigeration cycle system includes a first dual-suction compressor. The exhaust port of the first dual-suction compressor is sequentially connected to a condenser and a first gas-liquid separator. The gas outlet of the first gas-liquid separator is connected to a first capillary tube. The outlet of the first capillary tube is divided into two paths. One path is equipped with a first solenoid valve, and the other path is sequentially equipped with a second solenoid valve and a second gas-liquid separator. The outlet of the first solenoid valve and the gas outlet of the second gas-liquid separator are first combined into one path, and then connected to the auxiliary suction port of the first dual-suction compressor through a first pipeline.

[0005] The system also includes a second dual-suction compressor. The liquid outlets of the first gas-liquid separator and the second gas-liquid separator are first combined into one path, and then split into two paths. One path is equipped with a third solenoid valve, a second capillary tube, and a refrigerated evaporator in sequence. The outlet of the refrigerated evaporator is connected to the auxiliary suction port of the second dual-suction compressor through a second pipeline. The other path is equipped with a fourth solenoid valve, a third capillary tube, and a refrigerated evaporator in sequence. The outlet of the refrigerated evaporator is connected to the main suction port of the second dual-suction compressor. The exhaust port of the second dual-suction compressor is connected to the main suction port of the first dual-suction compressor.

[0006] Preferably, the first pipeline and the second pipeline are connected by a third pipeline.

[0007] Preferably, the first dual-intake compressor is a variable frequency compressor.

[0008] Preferably, the first dual-intake compressor can operate at a variable speed, with a high speed R > 3000 rpm and a low speed 1200 rpm ≤ R < 3000 rpm.

[0009] Preferably, in the high-speed mode of the first dual-intake compressor, the first solenoid valve is closed and the second solenoid valve is open.

[0010] Preferably, in the low-speed mode of the first dual-intake compressor, the first solenoid valve is open and the second solenoid valve is closed.

[0011] Preferably, the second dual-intake compressor is a fixed-frequency compressor.

[0012] Preferably, the second dual-suction compressor operates at a constant speed, with a constant speed R = 3000 rpm.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] This invention discloses a two-stage refrigeration cycle system. By increasing enthalpy through two-stage gas injection, the compressor's suction pressure is enhanced, thereby improving the system's cycle efficiency and ultimately increasing refrigeration efficiency. Furthermore, employing two compressors in series further increases the system pressure, thus further improving refrigeration efficiency. Attached Figure Description

[0015] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a system schematic diagram of Embodiment 1 of the present invention.

[0017] Figure 2 This is a system schematic diagram of Embodiment 2 of the present invention.

[0018] In the diagram: 1. First dual-suction compressor; 2. Second dual-suction compressor; 3. Condenser; 4. First gas-liquid separator; 5. First capillary tube; 6. First solenoid valve; 7. Second solenoid valve; 8. Second gas-liquid separator; 9. Third solenoid valve; 10. Second capillary tube; 11. Refrigerated evaporator; 12. Fourth solenoid valve; 13. Third capillary tube; 14. Refrigerated evaporator; 15. First pipeline; 16. Second pipeline; 17. Third pipeline; a. Exhaust port of the first dual-suction compressor b. Inlet of the first gas-liquid separator; c. Gas outlet of the first gas-liquid separator; d. Inlet of the second gas-liquid separator; e. Gas outlet of the second gas-liquid separator; f. Auxiliary suction port of the first dual-suction compressor; g. Liquid outlet of the first gas-liquid separator; h. Liquid outlet of the second gas-liquid separator; i. Auxiliary suction port of the second dual-suction compressor; j. Main suction port of the second dual-suction compressor; k. Discharge port of the second dual-suction compressor; l. Main suction port of the first dual-suction compressor. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0020] Example 1

[0021] like Figure 1 As shown, a preferred embodiment of the present invention provides a two-stage refrigeration cycle system, which includes the following components: a first dual-suction compressor 1, a second dual-suction compressor 2, a condenser 3, a first gas-liquid separator 4, a first capillary tube 5, a first solenoid valve 6, a second solenoid valve 7, a second gas-liquid separator 8, a third solenoid valve 9, a second capillary tube 10, a refrigeration evaporator 11, a fourth solenoid valve 12, a third capillary tube 13, and a freezing evaporator 14.

[0022] The first dual-suction compressor 1 has a secondary suction port, a main suction port and a discharge port. The first dual-suction compressor 1 is a variable frequency compressor. The refrigerator main controller controls the speed of the first dual-suction compressor 1 by changing the frequency. According to the different temperature control modes of the refrigerator, when the first dual-suction compressor 1 is running at high speed, R > 3000 rpm, and when it is running at low speed, 1200 rpm ≤ R < 3000 rpm.

[0023] The second dual-intake compressor 2 has a secondary intake port, a main intake port and an exhaust port. The second dual-intake compressor 2 is a fixed-frequency compressor that operates at a constant speed, R = 3000 rpm.

[0024] The first gas-liquid separator 4 and the second gas-liquid separator 8 are both used for gas-liquid separation, and each has an inlet, a gas outlet and a liquid outlet.

[0025] The connection relationships of the above components are as follows: the exhaust port a of the first dual-suction compressor is connected to the inlet of the condenser 3, the outlet of the condenser 3 is connected to the inlet b of the first gas-liquid separator, the gas outlet c of the first gas-liquid separator is connected to the inlet of the first capillary tube 5, the outlet of the first capillary tube 5 is divided into two paths, one path is equipped with a first solenoid valve 6, and the other path is equipped with a second solenoid valve 7. The outlet of the second solenoid valve 7 is connected to the inlet d of the second gas-liquid separator. The outlet of the first solenoid valve 6 and the gas outlet e of the second gas-liquid separator are first combined into one path, and then connected to the auxiliary suction port f of the first dual-suction compressor through the first pipeline 15.

[0026] The liquid outlet g of the first gas-liquid separator and the liquid outlet h of the second gas-liquid separator are first combined into one path, and then divided into two paths. One path is equipped with a third solenoid valve 9, a second capillary tube 10 and a refrigerated evaporator 11 in sequence. The outlet of the refrigerated evaporator 11 is connected to the auxiliary suction port i of the second dual-suction compressor through the second pipeline 16. The other path is equipped with a fourth solenoid valve 12, a third capillary tube 13 and a refrigerated evaporator 14 in sequence. The outlet of the refrigerated evaporator 14 is connected to the main suction port j of the second dual-suction compressor. The exhaust port k of the second dual-suction compressor is connected to the main suction port l of the first dual-suction compressor.

[0027] The working process of this refrigeration cycle system is as follows: When the refrigerator is first powered on, powered on again, in deep cooling mode, or after defrosting, the refrigerator requires a large cooling capacity, so the first dual-suction compressor 1 runs at high speed, while the first solenoid valve 6 is closed and the second solenoid valve 7 is open. The first dual-suction compressor 1 compresses the refrigerant into a high-temperature, high-pressure gaseous state, which is then liquefied by the condenser 3. At this time, the refrigerant is a gas-liquid two-phase mixture, which undergoes preliminary separation through the first gas-liquid separator 4. The gaseous refrigerant (actually a gas-liquid two-phase mixture, but mostly gaseous) is depressurized through the first capillary tube 5 and then enters the second gas-liquid separator 8 for secondary separation. The gaseous refrigerant separated by the second gas-liquid separator 8 enters the auxiliary suction port f of the first dual-suction compressor. The purpose of this is to replenish gas and increase enthalpy, thereby increasing the suction pressure of the first dual-suction compressor 1, and thus improving the system cycle efficiency, ultimately achieving improved refrigeration efficiency. The liquid refrigerant separated by the first gas-liquid separator 4 and the liquid refrigerant separated by the second gas-liquid separator 8 are combined and supplied to the refrigeration evaporator 11 and the freezing evaporator 14 as needed, specifically controlled by the third solenoid valve 9 and the fourth solenoid valve 12.

[0028] When the refrigerator is in normal cooling mode, the cooling capacity requirement is relatively low, so the first dual-suction compressor 1 operates at a low speed. Simultaneously, the first solenoid valve 6 is open and the second solenoid valve 7 is closed. The first dual-suction compressor 1 compresses the refrigerant into a high-temperature, high-pressure gaseous state, which is then liquefied by the condenser 3. At this point, the refrigerant is a two-phase mixture of gas and liquid. This mixture undergoes initial separation through the first gas-liquid separator 4. The gaseous refrigerant, after being depressurized by the first capillary tube 5, enters the auxiliary suction port f of the first dual-suction compressor. The purpose of this is to replenish the gas and increase the enthalpy, thereby increasing the suction pressure of the first dual-suction compressor 1 and improving the system's cycle efficiency, ultimately enhancing cooling efficiency. The liquid refrigerant separated by the first gas-liquid separator 4 is supplied to the refrigeration evaporator 11 and the freezing evaporator 14 as needed, specifically controlled by the third solenoid valve 9 and the fourth solenoid valve 12.

[0029] When the first dual-suction compressor 1 is running at high speed, the refrigerant has a high circulation efficiency, so it needs to undergo two gas-liquid separation processes, namely the first gas-liquid separator 4 and the second gas-liquid separator 8, to make the separation more thorough.

[0030] In addition, the above system uses two compressors connected in series, the purpose of which is to further increase the system pressure and thus improve the system's cooling efficiency.

[0031] Example 2

[0032] like Figure 2 As shown, a preferred embodiment of the present invention provides a two-stage refrigeration cycle system. Based on the above embodiment one, the first pipeline 15 and the second pipeline 16 are connected by a third pipeline 17. When the first dual-suction compressor 1 is running at high or low speed, the separated gaseous refrigerant can replenish the second dual-suction compressor 2 through the third pipeline 17 to increase the suction pressure of the second dual-suction compressor 2, thereby improving the system's refrigeration efficiency.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A two-stage refrigeration cycle system, characterized in that, The system includes a first dual-suction compressor. The exhaust port of the first dual-suction compressor is connected in sequence to a condenser and a first gas-liquid separator. The gas outlet of the first gas-liquid separator is connected to a first capillary tube. The outlet of the first capillary tube is divided into two paths. One path is equipped with a first solenoid valve, and the other path is equipped with a second solenoid valve and a second gas-liquid separator in sequence. The outlet of the first solenoid valve and the gas outlet of the second gas-liquid separator are first combined into one path, and then connected to the auxiliary suction port of the first dual-suction compressor through a first pipeline. The system also includes a second dual-suction compressor. The liquid outlets of the first gas-liquid separator and the second gas-liquid separator are first combined into one path, and then split into two paths. One path is equipped with a third solenoid valve, a second capillary tube, and a refrigerated evaporator in sequence. The outlet of the refrigerated evaporator is connected to the auxiliary suction port of the second dual-suction compressor through a second pipeline. The other path is equipped with a fourth solenoid valve, a third capillary tube, and a refrigerated evaporator in sequence. The outlet of the refrigerated evaporator is connected to the main suction port of the second dual-suction compressor. The exhaust port of the second dual-suction compressor is connected to the main suction port of the first dual-suction compressor.

2. The two-stage refrigeration cycle system according to claim 1, characterized in that, The first pipeline and the second pipeline are connected by a third pipeline.

3. The two-stage refrigeration cycle system according to claim 1, characterized in that, The first dual-suction compressor is a variable frequency compressor.

4. The two-stage refrigeration cycle system according to claim 1, characterized in that, The first dual-intake compressor can operate at variable speeds, with a high speed R > 3000 rpm and a low speed 1200 rpm ≤ R < 3000 rpm.

5. A two-stage refrigeration cycle system according to claim 4, characterized in that, In the high-speed mode of the first dual-intake compressor, the first solenoid valve is closed and the second solenoid valve is open.

6. A two-stage refrigeration cycle system according to claim 4, characterized in that, In the low-speed mode of the first dual-intake compressor, the first solenoid valve is open and the second solenoid valve is closed.

7. A two-stage refrigeration cycle system according to claim 1, characterized in that, The second dual-intake compressor is a fixed-frequency compressor.

8. A two-stage refrigeration cycle system according to claim 1, characterized in that, The second dual-suction compressor operates at a constant speed, R = 3000 rpm.

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