Hybrid refrigeration system, refrigeration device and control method

Abstract

The application provides a composite refrigeration system, a refrigeration device and a control method. The composite refrigeration system comprises: a cascade refrigeration unit, the cascade refrigeration unit comprising a high-temperature stage refrigeration circuit and a low-temperature stage refrigeration circuit, the high-temperature stage refrigeration circuit comprising an electromagnetic valve, a high-temperature evaporator in parallel connection, and an evaporating pipe in an evaporative condenser, the high-temperature evaporator and the evaporating pipe being connected to two outlet ends of the electromagnetic valve respectively; the low-temperature stage refrigeration circuit comprising a first low-temperature evaporator for providing cold energy to a tank, and a condensing pipe in the evaporative condenser upstream of the first low-temperature evaporator; a binary regenerative refrigeration circuit, the binary regenerative refrigeration circuit having a regenerator and a second low-temperature evaporator for providing cold energy to the tank; wherein the high-temperature evaporator can precool the second low-temperature evaporator; the pressure difference between the outlet and the inlet of the second low-temperature compressor when the binary regenerative refrigeration circuit starts can be reduced, and the rapid start of the binary regenerative refrigeration circuit and the low-temperature stage refrigeration circuit can be realized.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment technology, and in particular to a composite refrigeration system, a refrigeration device having the composite refrigeration system, and a control method for the refrigeration device. Background Technology

[0002] As living standards improve, people's understanding and requirements for food preservation have also deepened. Previously, people only focused on the preservation of refrigerated foods such as fruits and vegetables. Now, however, people are beginning to pay more attention to the preservation of frozen foods such as meat and fish. Research has found that deep freezing at around -90℃ to -40℃ has a better preservation effect on frozen foods.

[0003] The refrigeration systems used in existing refrigeration devices with a cooling temperature range of -90℃ to -40℃ are generally as follows: 1) A dual-stage regenerative refrigeration circuit with a regenerator. However, during the start-up phase of the dual-stage regenerative refrigeration circuit, due to the pressure difference established by the regenerator, there will be a period of time when the exhaust pressure in the refrigeration system is too high, which will damage the compressor; 2) A cascade system is used to cool the refrigeration chamber. That is, two compressors are used in one system, which has poor reliability. At the same time, only one system is used to control the temperature in the refrigeration chamber. When the preset shutdown temperature in the refrigeration chamber is high, the cascade system will experience frequent start-stop phenomena, which can easily lead to compressor damage. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention aims to provide a composite refrigeration system, a refrigeration device having the composite refrigeration system, and a control method for the refrigeration device, which can pre-cool the second low-temperature evaporator in the dual-stage regenerative refrigeration circuit and avoid high exhaust pressure during the period when the regenerator in the dual-stage regenerative refrigeration circuit establishes a pressure difference, thus preventing damage to the second low-temperature compressor in the dual-stage regenerative refrigeration circuit.

[0005] To achieve one of the above-mentioned objectives, the present invention provides a composite refrigeration system, comprising:

[0006] The cascade refrigeration unit includes a high-temperature refrigeration circuit and a low-temperature refrigeration circuit. The high-temperature refrigeration circuit includes a solenoid valve, a high-temperature evaporator connected in parallel, and an evaporator tube in an evaporator-condenser. The high-temperature evaporator and the evaporator tube are respectively connected to the two outlet ends of the solenoid valve. The low-temperature refrigeration circuit includes a first low-temperature evaporator for providing cooling to the liner and a condenser tube in an evaporator-condenser located upstream of the first low-temperature evaporator.

[0007] A dual-element regenerative refrigeration circuit, wherein the dual-element regenerative refrigeration circuit has a regenerator and a second low-temperature evaporator for providing cooling capacity to the chamber liner;

[0008] The high-temperature evaporator can pre-cool the second low-temperature evaporator.

[0009] As a further improvement of the present invention, the high-temperature stage refrigeration circuit further includes a high-temperature capillary tube, which is connected to the inlet end of the solenoid valve.

[0010] As a further improvement of the present invention, the high-temperature stage refrigeration circuit further includes a high-temperature capillary tube, which includes a first high-temperature capillary tube connected in series with the high-temperature evaporator and a second high-temperature capillary tube connected in series with the evaporator tube. The first high-temperature capillary tube and the second high-temperature capillary tube are respectively connected to the two outlet ends of the solenoid valve.

[0011] As a further improvement of the present invention, the high-temperature refrigeration circuit further includes a high-temperature compressor, a high-temperature condenser, a high-temperature drying filter, a high-temperature capillary tube, and a liquid storage tank. The high-temperature compressor, high-temperature condenser, high-temperature drying filter, high-temperature capillary tube, solenoid valve, and the parallel evaporator tube are sequentially connected to the high-temperature evaporator and the liquid storage tank to form a refrigeration circuit.

[0012] As a further improvement of the present invention, the high-temperature evaporator is disposed away from the chamber liner, and the high-temperature evaporator is in contact with at least a portion of the second low-temperature evaporator.

[0013] As a further improvement of the present invention, the low-temperature refrigeration circuit further includes a first low-temperature compressor, a first low-temperature condenser, an oil separator, a first low-temperature drying filter, and a first low-temperature capillary tube connected in sequence. The condenser tube in the evaporator-condenser is located between the first low-temperature drying filter and the first low-temperature capillary tube, and the first low-temperature evaporator is located between the first low-temperature capillary tube and the first low-temperature compressor.

[0014] As a further improvement of the present invention, the low-temperature stage refrigeration circuit further includes a first low-temperature return pipe located between the first low-temperature evaporator and the first low-temperature compressor, wherein the first low-temperature capillary tube is in thermal contact with the first low-temperature return pipe.

[0015] As a further improvement of the present invention, the dual-element regenerative refrigeration circuit further includes a second low-temperature compressor, a second low-temperature condenser, a second low-temperature drying filter, and a second low-temperature capillary tube connected in sequence. The second low-temperature evaporator is located between the second low-temperature capillary tube and the regenerator. The second low-temperature drying filter is connected to the first inlet of the regenerator. The second low-temperature capillary tube is connected to the first outlet of the regenerator. The second low-temperature evaporator is connected to the second inlet of the regenerator. The second low-temperature compressor is connected to the second outlet of the regenerator.

[0016] As a further improvement of the present invention, the dual-element regenerative refrigeration circuit further includes a second low-temperature return gas pipe located between the second low-temperature evaporator and the second inlet of the regenerator, wherein the second low-temperature capillary tube is in thermal contact with the second low-temperature return gas pipe.

[0017] As a further improvement of the present invention, the dual-element regenerative refrigeration circuit has a dual-element mixed refrigerant, which includes a first working fluid and a second working fluid. The first working fluid is one of R170, R1150, R23, R14, and R150, and the second working fluid is one of R290, R600, R600a, R134a, R1234fy, R1234ze, and R1270.

[0018] To achieve the above-mentioned objectives, the present invention also provides a refrigeration device, including a liner forming a refrigeration chamber and the above-mentioned composite refrigeration system that provides cooling capacity to the refrigeration chamber.

[0019] To achieve the above-mentioned objective, the present invention also provides a control method for controlling the above-mentioned refrigeration device, comprising the following steps:

[0020] Set a target temperature, a shutdown temperature, and a startup temperature inside the refrigeration room. The shutdown temperature is lower than the target temperature, the startup temperature is higher than the target temperature, and the target temperature is lower than a first preset temperature. When the target temperature is lower than the first preset temperature, the first preset temperature is higher than the startup temperature.

[0021] The temperature inside the refrigeration room is obtained. If the temperature inside the refrigeration room is greater than the second preset temperature, the high-temperature refrigeration circuit is started. The outlet end of the solenoid valve connected to the high-temperature evaporator is opened, and the outlet end of the solenoid valve connected to the evaporation tube is closed. The high-temperature evaporator precools the second low-temperature evaporator. After the temperature of the second low-temperature evaporator drops to less than the second preset temperature and is maintained for a first preset time, the dual-stage regenerative refrigeration circuit is started.

[0022] After the dual-element regenerative refrigeration circuit is started, the outlet end of the solenoid valve connected to the high-temperature evaporator is closed, and the outlet end of the solenoid valve connected to the evaporator tube is opened. After the temperature of the condenser tube drops to below the second preset temperature, the low-temperature stage refrigeration circuit is started; wherein, the second preset temperature is greater than the start-up temperature.

[0023] As a further improvement of the present invention, the high-temperature evaporator is located away from the chamber liner, and the high-temperature evaporator is in contact with at least part of the second low-temperature evaporator. The step is that after the temperature of the second low-temperature evaporator drops to less than the second preset temperature and is maintained for a first preset time, the dual-element regenerative refrigeration circuit is started. Specifically, after the temperature at the outlet end of the second low-temperature evaporator drops to less than the second preset temperature and is maintained for a first preset time, the dual-element regenerative refrigeration circuit is started.

[0024] As a further improvement of the present invention, both the high-temperature evaporator and the second low-temperature evaporator are attached to the inner chamber of the chamber. The step is that after the temperature of the second low-temperature evaporator drops to less than the second preset temperature and is maintained for a first preset time, the dual-element regenerative refrigeration circuit is started. Specifically, after the temperature in the refrigeration chamber drops to less than the second preset temperature and is maintained for a first preset time, the dual-element regenerative refrigeration circuit is started.

[0025] As a further improvement of the present invention, the second low-temperature evaporator is attached to the inner liner of the chamber; in setting the target temperature, shutdown temperature, and startup temperature in the refrigeration chamber, and wherein the target temperature is less than the first preset temperature, the control method further includes the following steps:

[0026] The temperature inside the refrigeration room is obtained. If the temperature inside the refrigeration room is lower than the second preset temperature and higher than the third preset temperature, then the high-temperature refrigeration circuit is started, the outlet end of the solenoid valve connected to the high-temperature evaporator is closed, and the outlet end of the solenoid valve connected to the evaporator tube is opened. After the high-temperature refrigeration circuit has been started for a second preset time, the low-temperature refrigeration circuit is started. After the low-temperature refrigeration circuit has been started for a third preset time, the dual-element regenerative refrigeration circuit is started. The third preset temperature is lower than the second preset temperature and higher than the start-up temperature.

[0027] As a further improvement of the present invention, the second low-temperature evaporator is attached to the inner liner of the chamber; in setting the target temperature, shutdown temperature, and startup temperature in the refrigeration chamber, and wherein the target temperature is less than the first preset temperature, the control method further includes the following steps:

[0028] The temperature inside the refrigeration room is obtained. If the temperature inside the refrigeration room is lower than the third preset temperature, the dual-element regenerative refrigeration circuit is started. When the temperature inside the refrigeration room reaches the shutdown temperature, the dual-element regenerative refrigeration circuit is stopped.

[0029] As a further improvement of the present invention, after the temperature inside the refrigeration room is lower than the third preset temperature and the dual-element regenerative refrigeration circuit is started, the control method further includes the following steps:

[0030] The start-up time of the dual-stage regenerative refrigeration circuit is recorded. If the start-up time is longer than the fourth preset time, the high-temperature stage refrigeration circuit is started. After the high-temperature stage refrigeration circuit has been started for a fifth preset time, the low-temperature stage refrigeration circuit is started.

[0031] As a further improvement of the present invention, when the temperature in the refrigeration room is less than the third preset temperature and the start-up time of the dual-element regenerative refrigeration circuit is greater than the third preset time, at the same time as the high-temperature stage refrigeration circuit is started, the outlet end of the solenoid valve connected to the high-temperature evaporator is closed, and the outlet end of the solenoid valve connected to the evaporation tube is opened.

[0032] As a further improvement of the present invention, after the high-temperature stage refrigeration circuit, the low-temperature stage refrigeration circuit, and the dual-element regenerative refrigeration circuit are all started, the control method further includes the following steps:

[0033] The temperature inside the refrigeration room is obtained. When the temperature inside the refrigeration room reaches the shutdown temperature, the low-temperature refrigeration circuit and the dual-element regenerative refrigeration circuit stop. After a sixth preset time period following the shutdown of the low-temperature refrigeration circuit and the dual-element regenerative refrigeration circuit, the high-temperature refrigeration circuit stops.

[0034] As a further improvement of the present invention, the high-temperature evaporator is used to provide cooling to the chamber liner, and the second low-temperature evaporator is attached to the chamber liner, wherein the high-temperature evaporator precools the second low-temperature evaporator through the chamber liner; the control method further includes the following steps:

[0035] Set a target temperature, a shutdown temperature, and a startup temperature inside the refrigeration room. The shutdown temperature is lower than the target temperature, the startup temperature is higher than the target temperature, and the target temperature is higher than a first preset temperature. When the target temperature is higher than the first preset temperature, the first preset temperature is lower than the shutdown temperature.

[0036] When the target temperature is greater than the first preset temperature, the high-temperature refrigeration circuit is activated, the outlet end of the solenoid valve connected to the high-temperature evaporator is opened, and the outlet end of the solenoid valve connected to the evaporator tube is closed, and the high-temperature evaporator provides cooling capacity to the refrigeration chamber.

[0037] Compared with the prior art, the present invention has the following beneficial effects: In the composite refrigeration system of the present invention, by connecting the high-temperature evaporator and the evaporator tube in parallel in the high-temperature stage refrigeration circuit, and selectively opening the two through a solenoid valve, the pre-cooling speed of the high-temperature evaporator to the second low-temperature evaporator in the dual-stage regenerative refrigeration circuit can be increased, thereby realizing the rapid start-up of the dual-stage regenerative refrigeration circuit. At the same time, by pre-cooling the second low-temperature evaporator in the dual-stage regenerative refrigeration circuit through the high-temperature evaporator, the pressure difference between the outlet and inlet of the second low-temperature compressor of the dual-stage regenerative refrigeration circuit can be reduced when the circuit starts up, avoiding damage to the second low-temperature compressor due to excessively high exhaust pressure, and enabling the rapid start-up of the low-temperature stage refrigeration circuit and the dual-stage regenerative refrigeration circuit. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the composite refrigeration system in the first embodiment of the present invention;

[0039] Figure 2 For having Figure 1 The control method of the refrigeration device in the composite refrigeration system shown;

[0040] Figure 3 This is a schematic diagram of the composite refrigeration system in the second embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the composite refrigeration system according to the third embodiment of the present invention;

[0042] Figure 5 For having Figure 4 The control method of the refrigeration device in the composite refrigeration system shown. Detailed Implementation

[0043] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. Please refer to the accompanying drawings for further details. Figures 1-5 The illustrations shown represent preferred embodiments of the present invention, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. However, it should be noted that these embodiments are not intended to limit the present invention, and any equivalent modifications or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are within the scope of protection of the present invention.

[0044] It should be understood that although the terms first, second, etc., may be used in this document to describe various elements or structures, the objects being described should not be limited by these terms. These terms are only used to distinguish these objects from one another.

[0045] First Implementation Method

[0046] Please refer to Figure 1As shown, this is a composite refrigeration system 10 in the first embodiment of the present invention. The composite refrigeration system 10 includes a cascade refrigeration unit 1 and a dual regenerative refrigeration circuit 2. The cascade refrigeration unit 1 includes a high-temperature stage refrigeration circuit 11 and a low-temperature stage refrigeration circuit 12. The low-temperature stage refrigeration circuit 12 and the dual regenerative refrigeration circuit 2 are used to provide cooling capacity to the same refrigeration chamber.

[0047] Please refer to Figure 1 As shown, the high-temperature stage refrigeration circuit 11 includes a high-temperature compressor 111, a high-temperature condenser 112, a high-temperature drying filter 113, a high-temperature capillary tube 114, an evaporator tube in an evaporator-condenser 115 connected in parallel, a high-temperature evaporator 116, and a liquid storage tank 117. The outlet end of the liquid storage tank 117 is connected to the inlet end of the high-temperature compressor 111 through a pipeline.

[0048] Furthermore, the high-temperature refrigeration circuit 11 also includes a high-temperature anti-condensation pipe 118 located between the high-temperature compressor 111 and the high-temperature condenser 112, which can achieve the effect of preventing condensation at a preset position in the refrigeration room, such as preventing condensation on the door of the refrigeration room.

[0049] Furthermore, the high-temperature refrigeration circuit 11 also includes a solenoid valve 119. The outlet end of the high-temperature capillary tube 114 is connected to the inlet end of the solenoid valve 119, and the high-temperature evaporator 116 and the evaporation tube are respectively connected to the two outlet ends of the solenoid valve 119. By controlling the solenoid valve 119, the high-temperature evaporator 116 and the evaporation tube can be controlled. For example, when the outlet end of the solenoid valve connected to the high-temperature evaporator 116 is open and the outlet end connected to the evaporation tube is closed, the refrigerant in the high-temperature refrigeration circuit 11 can only flow through the high-temperature evaporator 116, that is, at this time, only the high-temperature evaporator 116 can be used to provide cooling capacity; when the outlet end of the solenoid valve 119 connected to the high-temperature evaporator 116 is closed and the outlet end connected to the evaporation tube is open, the refrigerant in the high-temperature refrigeration circuit 11 can only flow through the evaporation tube, that is, at this time, only the evaporation tube can be used to provide cooling capacity.

[0050] Specifically, the refrigerant in the high-temperature stage refrigeration circuit 11 is a single high-temperature or medium-temperature refrigerant, such as R600a, R600, R290, R1270, etc. Of course, the refrigerant in the high-temperature stage refrigeration circuit 11 can also be a mixture of high-temperature and medium-temperature refrigerants.

[0051] In this embodiment, the high-temperature condenser 112 includes a high-temperature condenser body and a high-temperature condenser fan disposed close to the high-temperature condenser body. However, this is not a limitation; in other embodiments, the high-temperature condenser 112 may also be a casing-mounted condenser, in which case the high-temperature condenser fan is not required.

[0052] Furthermore, the low-temperature stage refrigeration circuit 12 includes a first low-temperature compressor 121, a first low-temperature condenser 122, an oil separator 123, a first low-temperature dryer filter 124, a condenser tube in an evaporator condenser 115, a first low-temperature capillary tube 125, and a first low-temperature evaporator 126 connected in sequence to form the refrigeration circuit. The first low-temperature evaporator 126 is connected to the inlet of the first low-temperature compressor 121.

[0053] The condenser in the low-temperature stage refrigeration circuit 12 exchanges heat with the evaporator in the high-temperature stage refrigeration circuit 11. The evaporator can reduce the temperature of the refrigerant in the low-temperature stage refrigeration circuit 12, thereby improving the cooling effect of the low-temperature stage refrigeration circuit 12.

[0054] Furthermore, the cryogenic stage refrigeration circuit 12 also includes a first cryogenic return gas pipe 127 located between the first cryogenic evaporator 126 and the first cryogenic compressor 121. The first cryogenic capillary tube 125 is in thermal contact with the first cryogenic return gas pipe 127.

[0055] The refrigerant vapor in the first low-temperature return pipe 127 cools the refrigerant liquid that enters the first low-temperature capillary tube 125 for throttling and pressure reduction, causing the refrigerant liquid to be subcooled to the evaporation temperature; the refrigerant liquid entering the first low-temperature capillary tube 125 for throttling and pressure reduction increases the temperature of the refrigerant vapor entering the first low-temperature return pipe 127 and further vaporizes the refrigerant liquid entrained in the refrigerant vapor, thereby ensuring the normal operation of the first low-temperature compressor 121 and improving the refrigeration efficiency.

[0056] Specifically, the first low-temperature capillary tube 125 and the first low-temperature return gas tube 127 can be connected by side-by-side soldering to form a thermal contact, or they can be wound together to form a thermal contact, or they can be connected by heat shrink tubing to form a thermal contact, etc.

[0057] Specifically, the refrigerant in the low-temperature stage refrigeration circuit 12 is a single medium-temperature or low-temperature refrigerant, such as R290, R170, R1150, R1270, etc. Of course, the refrigerant in the low-temperature stage refrigeration circuit 12 can also be a medium-temperature or mixed refrigerant.

[0058] Furthermore, the dual-element regenerative refrigeration circuit 2 includes a second cryogenic compressor 21, a second cryogenic condenser 22, a second cryogenic dryer filter 23, a regenerator 24, a second cryogenic capillary tube 25, and a second cryogenic evaporator 26 connected in sequence. The second cryogenic dryer filter 23 is connected to the first inlet of the regenerator 24, the second cryogenic capillary tube 25 is connected to the first outlet of the regenerator 24, the second cryogenic evaporator 26 is connected to the second inlet of the regenerator 24, and the second cryogenic compressor 21 is connected to the second outlet of the regenerator 24. The second cryogenic evaporator 26 is used to provide cooling capacity to the liner.

[0059] Specifically, the regenerator 24 has a first flow path connecting the first inlet and the first outlet, and a second flow path connecting the second inlet and the second outlet. After the dual-element regenerating refrigeration circuit 2 is started, the high-temperature dual-element mixed refrigerant flowing through the first flow path exchanges heat with the low-temperature dual-element mixed refrigerant flowing through the second flow path. The refrigerant vapor from the second low-temperature evaporator 26 can be used to cool the high-pressure refrigerant liquid before entering the second low-temperature capillary tube 25, so that the high-pressure refrigerant liquid before throttling is supercooled, avoiding vaporization before throttling. By using the high-pressure refrigerant liquid before entering the second low-temperature capillary tube 25 to increase the temperature of the refrigerant vapor entering the second low-temperature compressor 21 and make the refrigerant liquid entrained in the refrigerant vapor vaporize, the normal operation of the second low-temperature compressor 21 is ensured.

[0060] Specifically, the regenerator 24 can be a shell-and-tube regenerator, a tube-and-pipe regenerator, a spray regenerator, a finned tube regenerator, a plate regenerator, or a heat pipe, etc.

[0061] Furthermore, the dual-element regenerative refrigeration circuit 2 also includes a second low-temperature return gas pipe 27 located between the second low-temperature evaporator 26 and the second inlet of the regenerator 24, and the second low-temperature capillary tube 25 is in thermal contact with the second low-temperature return gas pipe 27.

[0062] The refrigerant vapor in the second low-temperature return pipe 27 cools the refrigerant liquid that enters the second low-temperature capillary tube 25 for throttling and pressure reduction, causing the refrigerant liquid to be subcooled to the evaporation temperature; the refrigerant liquid entering the second low-temperature capillary tube 25 for throttling and pressure reduction increases the temperature of the refrigerant vapor entering the second low-temperature return pipe 27 and further vaporizes the refrigerant liquid entrained in the refrigerant vapor, thereby ensuring the normal operation of the second low-temperature compressor 21 and improving refrigeration efficiency.

[0063] Specifically, the second low-temperature capillary tube 25 and the second low-temperature return gas tube 27 can be connected by side-by-side soldering to form a thermal contact, or they can be wound together to form a thermal contact, or they can be connected by heat shrink tubing to form a thermal contact, etc.

[0064] Furthermore, in this embodiment, the second low-temperature condenser 22 includes a second low-temperature condenser body and a second low-temperature condenser fan disposed near the second low-temperature condenser body. Of course, this is not a limitation; in other embodiments, the second low-temperature condenser 22 may also be a casing-mounted condenser, in which case the low-temperature condenser fan is not required.

[0065] Specifically, the binary refrigerant mixture in the binary regenerative refrigeration circuit 2 includes a first working fluid and a second working fluid. The first working fluid is one of R170, R1150, R23, R14, and R150, and the second working fluid is one of R290, R600, R600a, R134a, R1234fy, R1234ze, and R1270. For example, the binary refrigerant mixture may be a mixture of R600a and R1150, or a mixture of R600a and R170, or a mixture of R290 and R1150, or a mixture of R1270 and R1150, etc. This not only meets the requirements of the binary regenerative refrigeration circuit 2 for the amount of combustible refrigerant, but also allows the temperature inside the refrigeration chamber of the refrigeration unit to reach -90℃ to -40℃, achieving better preservation of food stored in the refrigeration chamber, while reducing power consumption and noise. In practical applications, the mass percentage of the two working fluids can be adjusted according to the volume of the refrigeration chamber, the ambient temperature, and the application scenario to achieve the ideal preservation effect.

[0066] Furthermore, the dual-element regenerative refrigeration circuit 2 also includes a low-temperature anti-condensation pipe 28 disposed between the second low-temperature condenser 22 and the second low-temperature drying filter 23 to prevent condensation on the door body.

[0067] Furthermore, the high-temperature evaporator 116 can pre-cool the second low-temperature evaporator 26. That is, before the dual-stage regenerative refrigeration circuit 2 is started, the high-temperature stage refrigeration circuit 11 is started first, and the second low-temperature evaporator 26 is pre-cooled by the high-temperature evaporator 116, which can reduce the pressure difference between the outlet and inlet of the second low-temperature compressor 21 when the dual-stage regenerative refrigeration circuit 2 is started, and avoid damage to the second low-temperature compressor 21 due to excessive exhaust pressure.

[0068] Specifically, in this embodiment, the high-temperature evaporator 116 is positioned away from the inner chamber, and the high-temperature evaporator 116 is in contact with at least a portion of the second low-temperature evaporator 26. That is, the high-temperature evaporator 116 is only used to directly pre-cool the second low-temperature evaporator 26, and the high-temperature evaporator 116 does not provide cooling capacity to the refrigeration chamber.

[0069] It is understood that the high-temperature evaporator 116 in the high-temperature stage refrigeration circuit 11 is only used to provide cooling capacity to the second low-temperature evaporator 26, and the evaporator tube in the high-temperature stage refrigeration circuit 11 is only used to provide cooling capacity to the condenser tube in the low-temperature stage refrigeration circuit 12. Therefore, the high-temperature stage refrigeration circuit 11 in the composite refrigeration system 10 cannot provide cooling capacity to the refrigeration chamber; only the low-temperature stage refrigeration circuit 12 and the dual-element regenerative refrigeration circuit 2 provide cooling capacity to the refrigeration chamber. At this time, the composite refrigeration system 10 is suitable for ultra-low temperature refrigeration. That is, the target temperature of the refrigeration device with the composite refrigeration system 10 is lower than the first preset temperature.

[0070] In one specific embodiment, the first preset temperature is -30°C. Of course, it is not limited to this.

[0071] Furthermore, the present invention also provides a refrigeration device, the refrigeration device comprising a liner forming a refrigeration chamber and the aforementioned composite refrigeration system 10 providing cooling capacity to the refrigeration chamber.

[0072] The structure of the composite refrigeration system 10 is as described above, and will not be repeated here.

[0073] Specifically, the first low-temperature evaporator 126 and the second low-temperature evaporator 26 are both attached to the inner chamber of the chamber, while the high-temperature evaporator 116 is positioned away from the inner chamber and is in contact with at least a portion of the second low-temperature evaporator 26. Pre-cooling the second low-temperature evaporator 26 through the high-temperature evaporator 116 reduces the pressure difference between the outlet and inlet of the second low-temperature compressor 21 when the dual-element regenerative refrigeration circuit 2 starts, preventing damage to the second low-temperature compressor 21 due to excessively high exhaust pressure.

[0074] Further, please refer to Figure 2 As shown, the present invention also provides a control method for controlling the above-mentioned refrigeration device.

[0075] It should be noted that, in this article, the start-up of the dual-stage regenerative refrigeration circuit 2 refers to the start-up of the second cryogenic compressor 21, and the shutdown of the dual-stage regenerative refrigeration circuit 2 refers to the shutdown of the second cryogenic compressor 21; the start-up of the high-temperature stage refrigeration circuit 11 refers to the start-up of the high-temperature compressor 111, and the shutdown of the high-temperature stage refrigeration circuit 11 refers to the shutdown of the high-temperature compressor 111; the start-up of the low-temperature stage refrigeration circuit 12 refers to the start-up of the first cryogenic compressor 121, and the shutdown of the low-temperature stage refrigeration circuit 12 refers to the shutdown of the first cryogenic compressor 121.

[0076] Specifically, the control method includes the following steps:

[0077] Set a target temperature, a shutdown temperature, and a startup temperature inside the refrigeration room. The shutdown temperature is lower than the target temperature, the startup temperature is higher than the target temperature, and the target temperature is lower than a first preset temperature. When the target temperature is lower than the first preset temperature, the first preset temperature is higher than the startup temperature.

[0078] The temperature inside the refrigeration room is obtained. If the temperature inside the refrigeration room is greater than the second preset temperature, the high-temperature refrigeration circuit 11 is started, the outlet end of the solenoid valve 3 connected to the high-temperature evaporator 116 is opened, and the outlet end of the solenoid valve 3 connected to the evaporation tube is closed. The high-temperature evaporator 116 precools the second low-temperature evaporator 26. After the temperature of the second low-temperature evaporator 26 drops to less than the second preset temperature and is maintained for a first preset time, the dual-element regenerative refrigeration circuit 2 is started.

[0079] After the dual-element regenerative refrigeration circuit 2 is started, the outlet end of the solenoid valve 3 connected to the high-temperature evaporator 116 is closed, and the outlet end of the solenoid valve 3 connected to the evaporator tube is opened. After the temperature of the condenser tube drops to less than the second preset temperature, the low-temperature stage refrigeration circuit 12 is started; wherein, the second preset temperature is greater than the start-up temperature.

[0080] As can be seen, in this embodiment, the high-temperature stage refrigeration circuit 11 in the composite refrigeration system 10 cannot provide cooling to the refrigeration chamber; only the low-temperature stage refrigeration circuit 12 and the dual-element regenerative refrigeration circuit 2 provide cooling to the refrigeration chamber. In this case, the composite refrigeration system 10 is suitable for ultra-low temperature refrigeration. That is, the target temperature of the refrigeration device having the composite refrigeration system 10 is lower than a first preset temperature.

[0081] In one specific embodiment, the first preset temperature is -30°C. Of course, it is not limited to this.

[0082] In one specific embodiment, the target temperature is -80°C, the shutdown temperature is -82°C, and the power-on temperature is -78°C.

[0083] When the target temperature is lower than the first preset temperature, the target temperature inside the refrigeration chamber is low. It is necessary to activate the dual-stage regenerative refrigeration circuit 2 and the low-temperature stage refrigeration circuit 12 to lower the temperature inside the refrigeration chamber below the target temperature to the shutdown temperature. At this time, it is first determined whether the temperature inside the refrigeration chamber is higher than the second preset temperature. If the temperature inside the refrigeration chamber is higher than the second preset temperature, it indicates that the temperature inside the refrigeration chamber is too high to pre-cool the second low-temperature evaporator 26 through the chamber liner. Therefore, the high-temperature stage refrigeration circuit 11 is activated, and the high-temperature evaporator 116 pre-cools the second low-temperature evaporator 26. This reduces the pressure difference between the outlet and inlet of the second low-temperature compressor 21 when the dual-stage regenerative refrigeration circuit 2 is activated, preventing damage to the second low-temperature compressor 21 due to excessively high exhaust pressure. After the dual-stage regenerative refrigeration circuit 2 is activated, the evaporator provides cooling to the condenser, lowering the temperature of the refrigerant in the low-temperature stage refrigeration circuit 12, which is beneficial for the subsequent smooth activation of the low-temperature stage refrigeration circuit 12.

[0084] By initially setting the refrigerant in the high-temperature stage refrigeration circuit 11 to flow only through the high-temperature evaporator 116, the refrigerant flow rate can be increased, which is beneficial for the rapid start-up of the dual-stage regenerative refrigeration circuit 2. After the dual-stage regenerative refrigeration circuit 2 starts up, setting the refrigerant in the high-temperature stage refrigeration circuit 11 to flow only through the evaporator tube increases the refrigerant flow rate and improves the cooling rate of the refrigerant in the low-temperature stage refrigeration circuit 12, which is beneficial for the rapid start-up of the low-temperature stage refrigeration circuit 12.

[0085] In one specific embodiment, the second preset temperature is greater than the first preset temperature, and the second preset temperature is -15°C. Of course, this is not a limitation.

[0086] Specifically, in the embodiment where the high-temperature evaporator 116 is located away from the inner chamber and is in contact with at least part of the second low-temperature evaporator 26, the step of starting the dual-element regenerative refrigeration circuit 2 after the temperature of the second low-temperature evaporator 26 drops below the second preset temperature and remains there for a first preset time is as follows: the dual-element regenerative refrigeration circuit 2 is started after the temperature at the outlet end of the second low-temperature evaporator 26 drops below the second preset temperature and remains there for a first preset time.

[0087] It is known that when the temperature at the outlet of the second low-temperature evaporator 26 drops below the second preset temperature and remains there for a first preset time, it is determined that the second low-temperature evaporator 26 has dropped to the pre-cooling target temperature. At this time, the dual-element regenerative refrigeration circuit 2 is activated, preventing damage to the second low-temperature compressor 21 due to excessively high exhaust pressure, and improving the refrigeration efficiency of the composite refrigeration system 10.

[0088] In this embodiment, the pre-cooling effect of the second low-temperature evaporator 26 can be directly and intuitively obtained by sensing the temperature at the outlet end of the second low-temperature evaporator 26, which is more accurate.

[0089] In one specific implementation, the first preset duration is 5 minutes, but of course, it is not limited to this.

[0090] Simultaneously, after the temperature of the condenser tube drops below the second preset temperature, it is determined that the temperature of the refrigerant in the low-temperature stage refrigeration circuit 12 has dropped to the preset temperature. At this time, the low-temperature stage refrigeration circuit 12 can start smoothly.

[0091] Furthermore, in setting the target temperature, shutdown temperature, and startup temperature within the refrigeration room, and wherein the target temperature is less than a first preset temperature, the control method further includes the following steps:

[0092] The temperature inside the refrigeration room is obtained. If the temperature inside the refrigeration room is lower than the second preset temperature, and at the same time, the temperature inside the refrigeration room is higher than the third preset temperature, then the high-temperature stage refrigeration circuit 11 is started, the outlet end of the solenoid valve 3 connected to the high-temperature evaporator 116 is closed, and the outlet end of the solenoid valve 3 connected to the evaporator tube is opened. After the high-temperature stage refrigeration circuit 11 is started for a second preset time, the low-temperature stage refrigeration circuit 12 is started. After the low-temperature stage refrigeration circuit 12 is started for a third preset time, the dual-element regenerative refrigeration circuit 2 is started. The third preset temperature is lower than the second preset temperature and the third preset temperature is higher than the start-up temperature.

[0093] When the target temperature is lower than the first preset temperature, the target temperature inside the refrigeration chamber is low, requiring the activation of the dual-element regenerative refrigeration circuit 2 and the low-temperature stage refrigeration circuit 12 to lower the temperature inside the refrigeration chamber to a shutdown temperature below the target temperature. It is understood that in this embodiment, the second low-temperature evaporator 26 is attached to the liner, meaning the refrigeration chamber transfers its cooling capacity to the second low-temperature evaporator 26 through the liner. If the temperature inside the refrigeration chamber is already lower than the second preset temperature, it indicates that the temperature of the second low-temperature evaporator 26 is already at the pre-cooling target temperature. Activating the dual-element regenerative refrigeration circuit 2 directly will not cause damage to the second low-temperature compressor 21 due to excessively high exhaust pressure. Therefore, when the target temperature is lower than the first preset temperature and the temperature in the refrigeration room is lower than the second preset temperature, the high-temperature refrigeration circuit 11 is activated, the outlet end of the solenoid valve 3 connected to the high-temperature evaporator 116 is closed, and the outlet end of the solenoid valve 3 connected to the evaporator tube is opened. The refrigerant in the high-temperature refrigeration circuit 11 flows only through the evaporator tube. That is, the high-temperature refrigeration circuit 11 will not pre-cool the second low-temperature evaporator 26. At this time, the high-temperature refrigeration circuit 11 only provides cooling to the condenser tube in the low-temperature refrigeration circuit 12.

[0094] Specifically, after the high-temperature stage refrigeration circuit 11 has been activated for a second preset time, the low-temperature stage refrigeration circuit 12 is activated, and after the low-temperature stage refrigeration circuit 12 has been activated for a third preset time, the dual-element regenerative refrigeration circuit 2 is activated. This avoids the problem of excessive instantaneous current caused by the simultaneous activation of the high-temperature stage refrigeration circuit 11, the low-temperature stage refrigeration circuit 12, and the dual-element regenerative refrigeration circuit 2.

[0095] In one specific embodiment, the third preset temperature is 8°C higher than the target temperature. Both the second preset duration and the third preset duration are 1 minute, but are not limited to this.

[0096] Furthermore, in setting the target temperature, shutdown temperature, and startup temperature within the refrigeration room, and wherein the target temperature is less than a first preset temperature, the control method further includes the following steps:

[0097] The temperature inside the refrigeration room is obtained. If the temperature inside the refrigeration room is lower than the third preset temperature, the dual-element regenerative refrigeration circuit 2 is started. When the temperature inside the refrigeration room reaches the shutdown temperature, the dual-element regenerative refrigeration circuit 2 is stopped.

[0098] When the temperature inside the refrigeration chamber is lower than the third preset temperature, it indicates that the temperature inside the refrigeration chamber is already low. Therefore, the temperature of the second low-temperature evaporator 26 is already below the pre-cooling target temperature. Directly activating the dual-element regenerative refrigeration circuit 2 will prevent damage to the second low-temperature compressor 21 due to excessively high exhaust pressure. Simultaneously, when the temperature inside the refrigeration chamber is lower than the third preset temperature, activating the dual-element regenerative refrigeration circuit 2 is sufficient to lower the temperature inside the refrigeration chamber to the target temperature. Thus, activating only the dual-element regenerative refrigeration circuit 2 when the temperature inside the refrigeration chamber is lower than the third preset temperature simplifies the control logic and achieves energy savings.

[0099] Furthermore, after the temperature inside the refrigeration room is lower than the third preset temperature and the dual-element regenerative refrigeration circuit 2 is activated, the control method further includes the following steps:

[0100] The duration of the dual-stage regenerative refrigeration circuit 2 is recorded. If the duration is longer than the fourth preset duration, the high-temperature stage refrigeration circuit 11 is started. After the high-temperature stage refrigeration circuit 11 has been started for a fifth preset duration, the low-temperature stage refrigeration circuit 12 is started.

[0101] If the temperature in the cooling room has not dropped to the shutdown temperature after the dual-stage regenerative refrigeration circuit 2 has been started for a fourth preset time, it indicates that the cooling demand is large. At this time, the high-temperature stage refrigeration circuit 11 can be started first to provide cooling to the condenser tube in the low-temperature stage refrigeration circuit 12, and then the low-temperature stage refrigeration circuit 12 can be started to provide cooling to the cooling room at the same time, so as to accelerate the efficiency of the temperature reduction in the cooling room.

[0102] In one specific implementation, the fourth preset duration is 30 minutes, and the fifth preset duration is 1 minute. Of course, this is not a limitation.

[0103] Specifically, it is known that when the temperature inside the refrigeration room is lower than the third preset temperature and the dual-element regenerative refrigeration circuit 2 is started, the second low-temperature evaporator 26 in the dual-element regenerative refrigeration circuit 2 does not need pre-cooling. Therefore, when the high-temperature stage refrigeration circuit 11 is started, the outlet end of the solenoid valve 119 connected to the high-temperature evaporator 116 is closed, and the outlet end of the solenoid valve connected to the evaporator tube is opened, so that the refrigerant in the high-temperature stage refrigeration circuit 11 flows only through the evaporator tube. This can accelerate the temperature reduction of the refrigerant in the low-temperature stage refrigeration circuit 12.

[0104] Furthermore, after the high-temperature stage refrigeration circuit 11, the low-temperature stage refrigeration circuit 12, and the dual-element regenerative refrigeration circuit 2 are all started, the control method further includes the following steps:

[0105] The temperature inside the refrigeration room is obtained. When the temperature inside the refrigeration room reaches the shutdown temperature, the low-temperature refrigeration circuit 12 and the dual-element regenerative refrigeration circuit 2 stop. After a sixth preset time period following the shutdown of the low-temperature refrigeration circuit 12 and the dual-element regenerative refrigeration circuit 2, the high-temperature refrigeration circuit 11 stops.

[0106] When the temperature in the refrigeration room reaches the shutdown temperature, the low-temperature refrigeration circuit 12 and the dual-element regenerative refrigeration circuit 2 are shut down first, and then the high-temperature refrigeration circuit 11 is shut down. As a result, the high-temperature refrigeration circuit 11 can further reduce the temperature of the condenser tube in the low-temperature refrigeration circuit 12 and reduce the pressure difference in the low-temperature refrigeration circuit 12 when it is started up next time.

[0107] Specifically, the sixth preset duration is 1 minute. Of course, it is not limited to this.

[0108] After the low-temperature stage refrigeration circuit 12, the dual-element regenerative refrigeration circuit 2, and the high-temperature stage refrigeration circuit 11 are all shut down, the temperature inside the refrigeration chamber is controlled by the dual-element regenerative refrigeration circuit 2 without changing the target temperature. That is, when the temperature inside the refrigeration chamber rises to the start-up temperature, the dual-element regenerative refrigeration circuit 2 starts to provide cooling to the refrigeration chamber, and when the temperature inside the refrigeration chamber drops to the shutdown temperature, the dual-element regenerative refrigeration circuit 2 shuts down.

[0109] Of course, it is understandable that if the door is left open for too long, or a large number of items are placed inside, or if the refrigeration unit unexpectedly stops, the temperature can be controlled according to the temperature range within the refrigerated room. This temperature range includes temperatures above the second preset temperature, temperatures below the second preset temperature but above the third preset temperature, and temperatures below the third preset temperature.

[0110] Second Implementation Method

[0111] Please refer to Figure 3The diagram shows a composite refrigeration system 10a in the second embodiment of the present invention. The difference between the composite refrigeration system 10a in the second embodiment and the composite refrigeration system 10 in the first embodiment is that the high-temperature capillary tube 114 in the high-temperature stage refrigeration circuit 11a includes a first high-temperature capillary tube 1141 connected in series with the high-temperature evaporator 116 and a second high-temperature capillary tube 1142 connected in series with the evaporator. Specifically, the first high-temperature capillary tube 1141 and the second high-temperature capillary tube 1142 are respectively connected to the two outlet ends of the solenoid valve 119. That is, the flow rate of the high-temperature evaporator 116 is controlled by the first high-temperature capillary tube 1141, and the flow rate of the evaporator tube is controlled by the second high-temperature capillary tube 1142. This improves the cooling rate of the high-temperature evaporator 116 pre-cooling the second low-temperature evaporator 26, enabling rapid start-up of the dual-stage regenerative refrigeration circuit 2. Correspondingly, it improves the cooling rate of the evaporator tube cooling the condenser, enabling rapid start-up of the low-temperature stage refrigeration circuit 12.

[0112] The composite refrigeration system 10a in the second embodiment of the present invention is the same as the composite refrigeration system 10 in the first embodiment except for the differences mentioned above, and will not be described again here.

[0113] Furthermore, the refrigeration device having the composite refrigeration system 10a in the second embodiment of the present invention is the same as the refrigeration device having the composite refrigeration system 10 in the first embodiment of the present invention, except for the differences mentioned above, and will not be described again here.

[0114] Furthermore, the control method of the refrigeration device having the composite refrigeration system 10a in the second embodiment of the present invention is the same as the control method of the refrigeration device having the composite refrigeration system 10 in the first embodiment of the present invention, and will not be described again here.

[0115] Third Implementation Method

[0116] Please refer to Figure 4 The figure shows the composite refrigeration system 10b in the third embodiment of the present invention. The difference between the composite refrigeration system 10b in the third embodiment of the present invention and the composite refrigeration system 10 in the first embodiment is that: the high-temperature evaporator 116 is used to provide cooling to the liner, and the second low-temperature evaporator 26 is attached to the liner. The high-temperature evaporator 116 precools the second low-temperature evaporator 26 through the liner.

[0117] That is, after the high-temperature refrigeration circuit 11 is started, the high-temperature evaporator 116 can provide cooling capacity to the refrigeration chamber formed by the chamber through the chamber liner. The cooling capacity in the refrigeration chamber cools the chamber liner, thereby pre-cooling the second low-temperature evaporator 26 attached to the chamber liner. This can reduce the pressure difference between the outlet and inlet of the second low-temperature compressor 21 when the dual-element regenerative refrigeration circuit 2 is started, and prevent the second low-temperature compressor 21 from being damaged due to excessive exhaust pressure.

[0118] In this embodiment, the high-temperature evaporator 116, the first low-temperature evaporator 126, and the second low-temperature evaporator 26 can all provide cooling capacity to the refrigeration room, that is, they can all be used to cool the refrigeration room. Therefore, when the preset target temperature in the refrigeration room is high, only the high-temperature stage refrigeration circuit 11 can be activated, and the high-temperature evaporator 116 in the high-temperature stage refrigeration circuit 11 can provide cooling capacity to the refrigeration room. When the preset target temperature in the refrigeration room is low, the high-temperature stage refrigeration circuit 11 is activated first, then the second low-temperature evaporator 26 is pre-cooled by the high-temperature evaporator 116 to activate the dual-element regenerative refrigeration circuit 2, and then the evaporator tube cools the condenser tube to activate the low-temperature refrigeration circuit. This ensures a high operating rate for the high-temperature stage refrigeration circuit 11, the low-temperature stage refrigeration circuit 12, and the dual-element regenerative refrigeration circuit 2, avoiding frequent start-ups and shutdowns.

[0119] The composite refrigeration system 10b in the third embodiment of the present invention is the same as the composite refrigeration system 10 in the first embodiment except for the differences mentioned above, and will not be described again here.

[0120] Furthermore, the difference between the refrigeration device having the composite refrigeration system 10b in the third embodiment of the present invention and the refrigeration device having the composite refrigeration system 10 in the first embodiment of the present invention is that the high-temperature evaporator 116 is attached to the inner liner of the box.

[0121] The refrigeration device having the composite refrigeration system 10b in the third embodiment of the present invention is the same as the refrigeration device having the composite refrigeration system 10 in the first embodiment of the present invention, except for the differences mentioned above, and will not be described again here.

[0122] Further, please refer to Figure 5 As shown, the difference between the control method of the refrigeration device having the composite refrigeration system 10b in the third embodiment of the present invention and the control method of the refrigeration device having the composite refrigeration system 10 in the first embodiment of the present invention is that:

[0123] In this embodiment, "the high-temperature evaporator 116 precooling the second low-temperature evaporator 26" specifically means that the high-temperature evaporator 116 provides cooling capacity to the inner chamber, and the inner chamber provides cooling capacity to the second low-temperature evaporator 26. That is, the high-temperature evaporator 116 provides cooling capacity to the refrigeration chamber formed by the inner chamber, transfers the cooling capacity to the inner chamber through the refrigeration chamber, and then transfers the cooling capacity to the second low-temperature evaporator 26 through the inner chamber, thus precooling the low-temperature evaporator.

[0124] Step 2: After the temperature of the second low-temperature evaporator 26 drops to below the second preset temperature and remains at that temperature for a first preset time, the dual-element regenerative refrigeration circuit 2 is activated. Specifically, after the temperature inside the refrigeration room drops to below the second preset temperature and remains at that temperature for a first preset time, the dual-element regenerative refrigeration circuit 2 is activated.

[0125] It is understood that the cooling chamber transfers cold energy to the second low-temperature evaporator 26 through the liner. When the temperature inside the cooling chamber drops below a second preset temperature and remains there for a first preset time, it is determined that the second low-temperature evaporator 26 has reached the target temperature. At this point, the dual-element regenerative refrigeration circuit 2 is activated, preventing damage to the second low-temperature compressor 21 due to excessively high exhaust pressure, and improving the refrigeration efficiency of the composite refrigeration system 10.

[0126] In this embodiment, the temperature of the second low-temperature evaporator 26 is estimated by directly using the temperature sensor originally installed in the refrigeration room to sense the temperature of the refrigeration room, which is less costly.

[0127] It is understood that, in this embodiment, the high-temperature refrigeration circuit 11 can be used to provide cooling capacity to the refrigeration chamber, thereby the target temperature of the refrigeration chamber can also be set to a higher level, such as -30℃ to -10℃.

[0128] Furthermore, the control method further includes the following steps:

[0129] Set a target temperature, a shutdown temperature, and a startup temperature inside the refrigeration room. The shutdown temperature is lower than the target temperature, the startup temperature is higher than the target temperature, and the target temperature is higher than a first preset temperature. When the target temperature is higher than the first preset temperature, the first preset temperature is lower than the shutdown temperature.

[0130] When the target temperature is greater than the first preset temperature, the high-temperature refrigeration circuit 11 is activated, the outlet end of the solenoid valve 119 connected to the high-temperature evaporator 116 is opened, and the outlet end of the solenoid valve 119 connected to the evaporator tube is closed. The refrigerant in the high-temperature refrigeration circuit 11 flows through the high-temperature evaporator to provide cooling to the refrigeration chamber.

[0131] In this embodiment, the temperature control of the cooling room from -30℃ to -10℃ can be achieved through the high-temperature stage refrigeration circuit 11, and the temperature control of the cooling room from -90℃ to -30℃ can be achieved through the low-temperature stage refrigeration circuit 12 and the dual-element regenerative refrigeration circuit 2. The temperature control is relatively stable, and the high-temperature stage refrigeration circuit 11, the low-temperature stage refrigeration circuit 12, and the dual-element regenerative refrigeration circuit 2 can all achieve a high start-up rate and will not start and stop frequently.

[0132] The control method of the refrigeration device having the composite refrigeration system 10b in the third embodiment of the present invention is the same as the control method of the refrigeration device having the composite refrigeration system 10 in the first embodiment of the present invention, except for the differences mentioned above, and will not be repeated here.

[0133] Compared with the prior art, in the composite refrigeration system 10 of the present invention, by connecting the high-temperature evaporator 116 in the high-temperature stage refrigeration circuit 11 in parallel with the evaporation tube, and selectively opening the two via the solenoid valve 119, the pre-cooling speed of the high-temperature evaporator 116 to the second low-temperature evaporator 26 in the dual-element regenerative refrigeration circuit 2 can be increased, thereby achieving rapid start-up of the dual-element regenerative refrigeration circuit 2. At the same time, by pre-cooling the second low-temperature evaporator 26 in the dual-element regenerative refrigeration circuit 2 with the high-temperature evaporator 116, the pressure difference between the outlet and inlet of the second low-temperature compressor 21 when the dual-element regenerative refrigeration circuit 2 starts can be reduced, thus avoiding damage to the second low-temperature compressor 21 due to excessively high exhaust pressure.

[0134] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0135] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite refrigeration system, characterized in that: include: The cascade refrigeration unit includes a high-temperature refrigeration circuit and a low-temperature refrigeration circuit. The high-temperature refrigeration circuit includes a solenoid valve, a high-temperature evaporator connected in parallel, and an evaporator tube in an evaporator-condenser. The high-temperature evaporator and the evaporator tube are respectively connected to the two outlet ends of the solenoid valve. The low-temperature refrigeration circuit includes a first low-temperature evaporator for providing cooling to the liner and a condenser tube in an evaporator-condenser located upstream of the first low-temperature evaporator. A dual-element regenerative refrigeration circuit, wherein the dual-element regenerative refrigeration circuit has a regenerator and a second low-temperature evaporator for providing cooling capacity to the chamber liner; The high-temperature evaporator can pre-cool the second low-temperature evaporator.

2. The composite refrigeration system according to claim 1, characterized in that: The high-temperature refrigeration circuit also includes a high-temperature capillary tube, which is connected to the inlet end of the solenoid valve.

3. The composite refrigeration system according to claim 1, characterized in that: The high-temperature stage refrigeration circuit also includes a high-temperature capillary tube, which includes a first high-temperature capillary tube connected in series with the high-temperature evaporator and a second high-temperature capillary tube connected in series with the evaporator tube. The first high-temperature capillary tube and the second high-temperature capillary tube are respectively connected to the two outlet ends of the solenoid valve.

4. The composite refrigeration system according to claim 2 or 3, characterized in that: The high-temperature refrigeration circuit also includes a high-temperature compressor, a high-temperature condenser, a high-temperature drying filter, a high-temperature capillary tube, and a liquid storage tank. The high-temperature compressor, high-temperature condenser, high-temperature drying filter, high-temperature capillary tube, solenoid valve, and the parallel evaporator tube are sequentially connected to the high-temperature evaporator and the liquid storage tank to form a refrigeration circuit.

5. The composite refrigeration system according to claim 1, characterized in that: The high-temperature evaporator is located away from the inner chamber, and the high-temperature evaporator is in contact with at least a portion of the second low-temperature evaporator.

6. The composite refrigeration system according to claim 1, characterized in that: The low-temperature refrigeration circuit further includes a first low-temperature compressor, a first low-temperature condenser, an oil separator, a first low-temperature drying filter, and a first low-temperature capillary tube connected in sequence. The condenser tube in the evaporator-condenser is located between the first low-temperature drying filter and the first low-temperature capillary tube, and the first low-temperature evaporator is located between the first low-temperature capillary tube and the first low-temperature compressor.

7. The composite refrigeration system according to claim 6, characterized in that: The low-temperature stage refrigeration circuit also includes a first low-temperature return pipe located between the first low-temperature evaporator and the first low-temperature compressor, and the first low-temperature capillary tube is in thermal contact with the first low-temperature return pipe.

8. The composite refrigeration system according to claim 1, characterized in that: The dual-element regenerative refrigeration circuit further includes a second low-temperature compressor, a second low-temperature condenser, a second low-temperature dryer filter, and a second low-temperature capillary tube connected in sequence. The second low-temperature evaporator is located between the second low-temperature capillary tube and the regenerator. The second low-temperature dryer filter is connected to the first inlet of the regenerator. The second low-temperature capillary tube is connected to the first outlet of the regenerator. The second low-temperature evaporator is connected to the second inlet of the regenerator. The second low-temperature compressor is connected to the second outlet of the regenerator.

9. The composite refrigeration system according to claim 8, characterized in that: The dual-element regenerative refrigeration circuit also includes a second low-temperature return pipe located between the second low-temperature evaporator and the second inlet of the regenerator, and the second low-temperature capillary tube is in thermal contact with the second low-temperature return pipe.

10. The composite refrigeration system according to claim 1, characterized in that: The dual-component regenerative refrigeration circuit contains a dual-component mixed refrigerant, which includes a first working fluid and a second working fluid. The first working fluid is one of R170, R1150, R23, R14, and R150, and the second working fluid is one of R290, R600, R600a, R134a, R1234fy, R1234ze, and R1270.

11. A refrigeration apparatus comprising a liner forming a refrigeration chamber, characterized in that: The refrigeration device further includes the composite refrigeration system described in any one of claims 1-10 above, which provides cooling capacity to the refrigerated room.

12. A control method for controlling the refrigeration device according to claim 11, characterized in that: The control method includes the following steps: Set a target temperature, a shutdown temperature, and a startup temperature inside the refrigeration room. The shutdown temperature is lower than the target temperature, the startup temperature is higher than the target temperature, and the target temperature is lower than a first preset temperature. When the target temperature is lower than the first preset temperature, the first preset temperature is higher than the startup temperature. The temperature inside the refrigeration room is obtained. If the temperature inside the refrigeration room is greater than the second preset temperature, the high-temperature refrigeration circuit is started. The outlet end of the solenoid valve connected to the high-temperature evaporator is opened, and the outlet end of the solenoid valve connected to the evaporation tube is closed. The high-temperature evaporator precools the second low-temperature evaporator. After the temperature of the second low-temperature evaporator drops to less than the second preset temperature and is maintained for a first preset time, the dual-stage regenerative refrigeration circuit is started. After the dual-element regenerative refrigeration circuit is started, the outlet end of the solenoid valve connected to the high-temperature evaporator is closed, and the outlet end of the solenoid valve connected to the evaporator tube is opened. After the temperature of the condenser tube drops to below the second preset temperature, the low-temperature stage refrigeration circuit is started; wherein, the second preset temperature is greater than the start-up temperature.

13. The control method according to claim 12, characterized in that: The high-temperature evaporator is located away from the inner chamber and is in contact with at least part of the second low-temperature evaporator. The step is that after the temperature of the second low-temperature evaporator drops to below the second preset temperature and is maintained for a first preset time, the dual-element regenerative refrigeration circuit is started. Specifically, after the temperature at the outlet end of the second low-temperature evaporator drops to below the second preset temperature and is maintained for a first preset time, the dual-element regenerative refrigeration circuit is started.

14. The control method according to claim 12, characterized in that: Both the high-temperature evaporator and the second low-temperature evaporator are attached to the inner chamber of the chamber. The step is that after the temperature of the second low-temperature evaporator drops to a temperature lower than the second preset temperature and remains at a temperature for a first preset time, the dual-element regenerative refrigeration circuit is activated. Specifically, after the temperature inside the refrigeration chamber drops to a temperature lower than the second preset temperature and remains at a temperature for a first preset time, the dual-element regenerative refrigeration circuit is activated.

15. The control method according to claim 12, characterized in that: The second low-temperature evaporator is attached to the inner chamber of the container; the control method further includes the following steps: setting a target temperature, a shutdown temperature, and a startup temperature within the refrigeration chamber, wherein the target temperature is lower than a first preset temperature. The temperature inside the refrigeration room is obtained. If the temperature inside the refrigeration room is lower than the second preset temperature and higher than the third preset temperature, then the high-temperature refrigeration circuit is started, the outlet end of the solenoid valve connected to the high-temperature evaporator is closed, and the outlet end of the solenoid valve connected to the evaporator tube is opened. After the high-temperature refrigeration circuit has been started for a second preset time, the low-temperature refrigeration circuit is started. After the low-temperature refrigeration circuit has been started for a third preset time, the dual-element regenerative refrigeration circuit is started. The third preset temperature is lower than the second preset temperature and higher than the start-up temperature.

16. The control method according to claim 12, characterized in that: The second low-temperature evaporator is attached to the inner chamber of the container; the control method further includes the following steps: setting a target temperature, a shutdown temperature, and a startup temperature within the refrigeration chamber, wherein the target temperature is lower than a first preset temperature. The temperature inside the refrigeration room is obtained. If the temperature inside the refrigeration room is lower than the third preset temperature, the dual-element regenerative refrigeration circuit is started. When the temperature inside the refrigeration room reaches the shutdown temperature, the dual-element regenerative refrigeration circuit is stopped.

17. The control method according to claim 16, characterized in that: After the temperature inside the refrigeration room is lower than the third preset temperature and the dual-element regenerative refrigeration circuit is activated, the control method further includes the following steps: The start-up time of the dual-stage regenerative refrigeration circuit is recorded. If the start-up time is longer than the fourth preset time, the high-temperature stage refrigeration circuit is started. After the high-temperature stage refrigeration circuit has been started for a fifth preset time, the low-temperature stage refrigeration circuit is started.

18. The control method according to claim 17, characterized in that: When the temperature inside the refrigeration room is lower than the third preset temperature and the start-up time of the dual-element regenerative refrigeration circuit is longer than the third preset time, at the same time the high-temperature refrigeration circuit starts, the outlet end of the solenoid valve connected to the high-temperature evaporator is closed, and the outlet end of the solenoid valve connected to the evaporation tube is opened.

19. The control method according to claim 12, 15, or 17, characterized in that: After the high-temperature stage refrigeration circuit, the low-temperature stage refrigeration circuit, and the dual-element regenerative refrigeration circuit are all started, the control method further includes the following steps: The temperature inside the refrigeration room is obtained. When the temperature inside the refrigeration room reaches the shutdown temperature, the low-temperature refrigeration circuit and the dual-element regenerative refrigeration circuit stop. After a sixth preset time period following the shutdown of the low-temperature refrigeration circuit and the dual-element regenerative refrigeration circuit, the high-temperature refrigeration circuit stops.

20. The control method according to claim 12, characterized in that: The high-temperature evaporator is used to provide cooling to the chamber liner, and the second low-temperature evaporator is attached to the chamber liner. The high-temperature evaporator precools the second low-temperature evaporator through the chamber liner. The control method further includes the following steps: Set a target temperature, a shutdown temperature, and a startup temperature inside the refrigeration room. The shutdown temperature is lower than the target temperature, the startup temperature is higher than the target temperature, and the target temperature is higher than a first preset temperature. When the target temperature is higher than the first preset temperature, the first preset temperature is lower than the shutdown temperature. When the target temperature is greater than the first preset temperature, the high-temperature refrigeration circuit is activated, the outlet end of the solenoid valve connected to the high-temperature evaporator is opened, and the outlet end of the solenoid valve connected to the evaporator tube is closed, and the high-temperature evaporator provides cooling capacity to the refrigeration chamber.

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