Refrigeration control method, two-stage refrigeration system and refrigeration equipment

Abstract

The invention provides a refrigeration control method, a two-stage refrigeration system and refrigeration equipment. The two-stage refrigeration system comprises a refrigeration system composed of two-stage compression and interstage refrigerant branches, and when the freezing area and the refrigeration area both have refrigeration requirements, a hierarchical control strategy can be adopted. Firstly, a freezing area can be refrigerated through a first-stage refrigeration flow path, namely, the freezing area is refrigerated through two-stage compression formed by a low-temperature compressor and a high-temperature compressor, so that the refrigeration requirement of the freezing area is met; meanwhile, the second-stage refrigeration flow path and the inter-stage refrigeration flow path can be selected to refrigerate the refrigeration area according to the refrigeration priority modes of the freezing area and the refrigeration area, so that the high refrigeration requirement of the freezing area is met, and the invalid power consumption of the low-temperature compressor can be reduced through intermediate temperature optimization; the two-stage refrigeration system achieves the energy-saving target under the condition that the refrigeration requirement is met, the energy consumption of the whole two-stage refrigeration system is reduced, and the use experience of a user is improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of refrigeration, and particularly relates to a refrigeration control method, a two-stage refrigeration system and a refrigeration device. BACKGROUND

[0002] Some cold storage generally contains a freezer and a refrigeration chamber, the temperature of the freezer is generally-18 DEG C, and the temperature of the refrigeration chamber is generally 0 DEG C. In the related art, a low-temperature compressor and a high-temperature compressor are generally connected in series to form a two-stage refrigeration system, and an intercooler is arranged between the two compressors, which can supply liquid refrigeration to the refrigeration chamber. Compared with the conventional low-temperature / high-temperature compressors respectively providing refrigeration for the freezer / refrigeration chamber, the two-stage compression can improve the energy efficiency of low-temperature refrigeration. However, when the freezer and the refrigeration chamber both need refrigeration, in order to give consideration to the refrigeration of the refrigeration chamber, the intermediate temperature is the evaporation temperature corresponding to the temperature of the refrigeration chamber, rather than the optimal intermediate temperature of the two-stage compression, which is easy to cause the increase of the energy consumption of the low-temperature compressor. SUMMARY

[0003] In view of this, in order to solve the technical problem of high energy consumption of the low-temperature compressor in the two-stage refrigeration system in the prior art when the freezer and the refrigeration chamber both need refrigeration, the present disclosure provides a refrigeration control method, a two-stage refrigeration system and a refrigeration device.

[0004] According to a first aspect of an embodiment of the present disclosure, a refrigeration control method is provided, which is applied to a two-stage refrigeration system, the two-stage refrigeration system comprising a low-temperature compressor, a high-temperature compressor, an intercooler, a refrigeration chamber evaporator and a freezer evaporator; the refrigeration chamber evaporator comprises a first refrigerant flow path and a second refrigerant flow path; the low-temperature compressor, the high-temperature compressor, the intercooler and the freezer evaporator form a first-stage refrigeration flow path, which is used to provide refrigeration for a freezer area where the freezer evaporator is located; the high-temperature compressor, the intercooler and the first refrigerant flow path of the refrigeration chamber evaporator form a second-stage refrigeration flow path, which is used to provide refrigeration for a refrigeration area where the refrigeration chamber evaporator is located; the two-stage refrigeration system further comprises a first-stage inter-refrigerant branch and a second-stage inter-refrigerant branch, the high-temperature compressor, the first-stage inter-refrigerant branch, the second refrigerant flow path of the refrigeration chamber evaporator and the second-stage inter-refrigerant branch form an inter-stage refrigeration flow path, which is used to provide refrigeration for the refrigeration area;

[0005] The refrigeration control method comprises:

[0006] In the case that both the freezer area and the refrigeration area have refrigeration requirements, the first-stage refrigeration flow path is controlled to provide refrigeration for the freezer area, and the second-stage refrigeration flow path or the inter-stage refrigeration flow path is selected to provide refrigeration for the refrigeration area according to a refrigeration priority mode of the freezer area and the refrigeration area.

[0007] In an alternative embodiment, the selecting the second-stage refrigeration flow path or the inter-stage refrigeration flow path for refrigerating the refrigeration compartment according to the refrigeration priority mode of the freezing compartment and the refrigeration compartment comprises:

[0008] If it is determined that the refrigeration priority mode of the freezing compartment and the refrigeration compartment is the freezing priority mode, the inter-stage refrigeration flow path is controlled to refrigerate the refrigeration compartment.

[0009] In an alternative embodiment, the selecting the second-stage refrigeration flow path or the inter-stage refrigeration flow path for refrigerating the refrigeration compartment according to the refrigeration priority mode of the freezing compartment and the refrigeration compartment comprises:

[0010] If it is determined that the refrigeration priority mode of the freezing compartment and the refrigeration compartment is the freezing priority mode, the second-stage refrigeration flow path is controlled to refrigerate the refrigeration compartment.

[0011] In an alternative embodiment, the refrigeration control method comprises:

[0012] In the case that both the freezing compartment and the refrigeration compartment have refrigeration demands, the refrigeration priority mode of the freezing compartment and the refrigeration compartment is determined according to a load ratio between the freezing compartment and the refrigeration compartment.

[0013] In an alternative embodiment, the determining the refrigeration priority mode of the freezing compartment and the refrigeration compartment according to the load ratio between the freezing compartment and the refrigeration compartment comprises:

[0014] If it is determined that the load ratio between the freezing compartment and the refrigeration compartment is greater than or equal to a load ratio limit value, the refrigeration priority mode of the freezing compartment and the refrigeration compartment is determined to be the freezing priority mode.

[0015] In an alternative embodiment, the determining the refrigeration priority mode of the freezing compartment and the refrigeration compartment according to the load ratio between the freezing compartment and the refrigeration compartment comprises:

[0016] If it is determined that the load ratio between the freezing compartment and the refrigeration compartment is less than a load ratio limit value, the refrigeration priority mode of the freezing compartment and the refrigeration compartment is determined to be the refrigeration priority mode.

[0017] In an alternative embodiment, the refrigeration control method comprises:

[0018] In the case that the freezing compartment has no refrigeration demand and the refrigeration compartment has a refrigeration demand, the second-stage refrigeration flow path is controlled to refrigerate the refrigeration compartment.

[0019] In an alternative embodiment, the refrigeration control method comprises:

[0020] In a case where the freezing zone has a refrigeration demand and the refrigeration zone has no refrigeration demand, the first-stage refrigeration flow path is controlled to refrigerate the freezing zone.

[0021] According to a second aspect of the embodiments of the present disclosure, a dual-stage refrigeration system is provided, which comprises a low-temperature compressor, a high-temperature compressor, an intermediate cooler, a refrigeration evaporator, and a freezing evaporator; the refrigeration evaporator comprises a first refrigerant flow path and a second refrigerant flow path;

[0022] The low-temperature compressor, the high-temperature compressor, the intermediate cooler, and the freezing evaporator form a first-stage refrigeration flow path, which is used to refrigerate a freezing zone where the freezing evaporator is located;

[0023] The high-temperature compressor, the intermediate cooler, and the first refrigerant flow path in the refrigeration evaporator form a second-stage refrigeration flow path, which is used to refrigerate a refrigeration zone where the refrigeration evaporator is located;

[0024] The dual-stage refrigeration system further comprises a first-stage inter-refrigerant branch and a second-stage inter-refrigerant branch; the high-temperature compressor, the first-stage inter-refrigerant branch, the second refrigerant flow path of the refrigeration evaporator, and the second-stage inter-refrigerant branch form an inter-stage refrigeration flow path, which is used to refrigerate the refrigeration zone;

[0025] In the dual-stage refrigeration system, in a case where both the freezing zone and the refrigeration zone have a refrigeration demand, the first-stage refrigeration flow path is controlled to refrigerate the freezing zone, and the second-stage refrigeration flow path or the inter-stage refrigeration flow path is selected to refrigerate the refrigeration zone according to a refrigeration priority mode of the freezing zone and the refrigeration zone.

[0026] In an optional embodiment, the dual-stage refrigeration system comprises a condenser, the first-stage inter-refrigerant branch comprises a first throttling valve, and in the inter-stage refrigeration flow path, the first-stage inter-refrigerant branch is located between the condenser and the second refrigerant flow path.

[0027] In an optional embodiment, the first-stage inter-refrigerant branch and / or the second-stage inter-refrigerant branch comprises a solenoid valve.

[0028] According to a third aspect of the embodiments of the present disclosure, a refrigeration device is provided, which comprises the dual-stage refrigeration system according to any one of the second aspect.

[0029] The technical scheme provided by the embodiment of the present disclosure can include the following beneficial effects: in the present disclosure, the two-stage refrigeration system includes a refrigeration system composed of two-stage compression and an inter-stage refrigerant branch, and when refrigeration is required in both the freezing area and the refrigeration area, a hierarchical control strategy can be adopted. First, the freezing area can be refrigerated through the first-stage refrigeration flow path, that is, the freezing area is refrigerated by the two-stage compression composed of the low-temperature compressor and the high-temperature compressor, to ensure the refrigeration requirement of the freezing area; at the same time, the second-stage refrigeration flow path and the inter-stage refrigeration flow path can be selected according to the refrigeration priority mode of the freezing area and the refrigeration area to refrigerate the refrigeration area. The refrigeration of the refrigeration area is based on the refrigeration priority mode of the freezing area and the refrigeration area to adopt a path selection mechanism, for example, when it is necessary to preferentially ensure the refrigeration effect of the freezing area, the inter-stage refrigeration flow path can be used to refrigerate the refrigeration area, that is, the medium-temperature refrigerant discharged by the high-temperature compressor is directly branched to the second refrigerant flow path of the refrigeration evaporator, to avoid the temperature of the intercooler being raised by the refrigeration area requirement, thereby maintaining the optimal intermediate temperature of the two-stage compression; when the refrigeration area needs to be preferentially refrigerated, the second-stage refrigeration flow path driven by the high-temperature compressor alone can be switched to, to better ensure the refrigeration requirement of the refrigeration area. The dynamic path selection mechanism of the present disclosure coordinates the refrigerant distribution of the two-stage compression, when the freezing area and the refrigeration area are refrigerated at the same time, the high refrigeration requirement of the freezing area is met, and the invalid power consumption of the low-temperature compressor is reduced through the intermediate temperature optimization, so that the two-stage refrigeration system meets the refrigeration requirement and achieves the energy saving target, reduces the energy consumption of the entire two-stage refrigeration system, and improves the user experience.

[0030] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0033] One or more embodiments are exemplarily illustrated by the pictures in the drawings corresponding thereto, and these exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified. The drawings in the drawings do not constitute a proportional limitation.

[0034] Figure 1 is a flow path schematic diagram of a two-stage refrigeration system according to an exemplary embodiment.

[0035] Figure 2 is a flowchart of a refrigeration control method according to an exemplary embodiment.

[0036] Figure 3 is another flowchart of a refrigeration control method according to an exemplary embodiment.

[0037] wherein:

[0038] 1, low temperature compressor; 2, high temperature compressor; 3, intermediate cooler; 4, freezing evaporator; 5, refrigerating evaporator; 51, first refrigerant flow path; 52, second refrigerant flow path; 6, first inter-stage refrigerant branch; 7, second inter-stage refrigerant branch;

[0039] 11, first expansion valve; 12, second expansion valve; 13, third expansion valve; 14, solenoid valve; 15, refrigerant pump. DETAILED DESCRIPTION

[0040] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0041] The following disclosure provides many different embodiments, or examples, for implementing different aspects, embodiments and / or configurations of the present application. For simplicity, the present disclosure focuses on the primary components and settings of the particular examples. Of course, they are merely examples and are presented to provide a thorough description of the application. Moreover, the present application can refer to a reference numeral and / or letter in different examples. Such repetition is for the sake of simplicity and clarity and does not indicate a relationship between the various embodiments and / or settings discussed.

[0042] For ease of description, spatial relative terms can be used herein to describe the positional relationship or movement of one element or feature relative to another element or feature as shown in the drawings, such as "inner", "outer", "inside", "outside", "lower", "below", "upper", "above", "front", "back", and the like. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawings is turned over or reversed, or the device is moved or rotated, the directional indications are also changed accordingly, for example, an element described as "below" or "under" another element or feature will be oriented "above" or "above" the other element or feature. Therefore, the example term "below" can include both upward and downward orientations. The device can be additionally oriented (rotated 90 degrees or in other directions) and the spatial relative relationship descriptors used herein are interpreted accordingly.

[0043] It should be noted that the drawings provided in the following embodiments only schematically illustrate the basic concepts of the present application, and only the components related to the present application are shown in the drawings, rather than being drawn according to the number, shape and size of the components in actual implementation. The shapes, numbers and proportions of the components in actual implementation can be arbitrarily changed, and the layout pattern of the components can be more complex.

[0044] The embodiments of the present application will be described below with reference to the drawings and preferred embodiments, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in the present specification. The present application can also be implemented or applied by means of other different specific embodiments, and the details in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be understood that the preferred embodiments are only for illustrating the present application, and are not intended to limit the protection scope of the present application.

[0045] In order to solve the technical problem of high energy consumption of the low-temperature compressor in the dual-stage refrigeration system when both the freezer and the refrigerator need refrigeration in the prior art, the present disclosure provides a refrigeration control method, a dual-stage refrigeration system and a refrigeration equipment.

[0046] In the present disclosure, the two-stage refrigeration system includes a two-stage compression and an inter-stage refrigerant branch, and when there is a refrigeration demand in both the freezing zone and the refrigeration zone, a hierarchical control strategy can be adopted. First, the first-stage refrigeration flow path can be used to refrigerate the freezing zone, i.e., the two-stage compression formed by the low-temperature compressor and the high-temperature compressor is used to refrigerate the freezing zone to ensure the refrigeration demand of the freezing zone. At the same time, the second-stage refrigeration flow path and the inter-stage refrigeration flow path can be selected according to the refrigeration priority mode of the freezing zone and the refrigeration zone to refrigerate the refrigeration zone. The refrigeration of the refrigeration zone is based on the refrigeration priority mode of the freezing zone and the refrigeration zone to adopt a path selection mechanism, for example, when it is necessary to prioritize the refrigeration effect of the freezing zone, the inter-stage refrigeration flow path can be used to refrigerate the refrigeration zone, i.e., the medium-temperature refrigerant discharged by the high-temperature compressor is directly branched to the second refrigerant flow path of the refrigeration evaporator, so as to avoid the temperature of the intercooler being raised by the demand of the refrigeration zone, thereby maintaining the optimal intermediate temperature of the two-stage compression; when the refrigeration zone needs to be prioritized, the second-stage refrigeration flow path driven by the high-temperature compressor alone can be switched to, so as to better ensure the refrigeration demand of the refrigeration zone. The dynamic path selection mechanism of the present disclosure coordinates the refrigerant distribution of the two-stage compression, and when the freezing zone and the refrigeration zone are refrigerated at the same time, the high refrigeration demand of the freezing zone is met, and the invalid power consumption of the low-temperature compressor is reduced by optimizing the intermediate temperature, so that the two-stage refrigeration system meets the refrigeration demand and achieves the energy saving target, reduces the energy consumption of the entire two-stage refrigeration system, and improves the user experience.

[0047] In one example embodiment, referring to Figure 1 and Figure 2 a two-stage refrigeration system is provided, as well as a refrigeration device comprising the above-mentioned two-stage refrigeration system, and a refrigeration control method applied to the two-stage refrigeration system, i.e., the two-stage refrigeration system is used to implement the above-mentioned refrigeration control method. In this embodiment, the two-stage refrigeration system includes a low-temperature compressor 1, a high-temperature compressor 2, an intercooler 3, a refrigeration evaporator 5, and a freezing evaporator 4.

[0048] The refrigeration evaporator 5 can be arranged in the refrigeration zone and used to refrigerate the refrigeration zone. The freezing evaporator 4 can be arranged in the freezing zone and used to refrigerate the freezing zone. For example, for a cold storage that includes both a freezing chamber and a refrigeration chamber, the refrigeration zone refers to the refrigeration chamber, and the refrigeration target temperature thereof can be 0°C. The refrigeration evaporator 5 is used to refrigerate the refrigeration chamber so that the temperature of the refrigeration chamber reaches 0°C or below. The freezing zone refers to the freezing chamber, and the freezing target temperature thereof can be -18°C. The freezing evaporator 4 is used to refrigerate the freezing chamber so that the temperature of the freezing chamber reaches -18°C or below.

[0049] The low-temperature compressor 1, the high-temperature compressor 2, the intermediate cooler 3 and the freezing evaporator 4 form a first-stage refrigeration flow path for refrigerating a freezing area in which the freezing evaporator 4 is located. The refrigeration evaporator 5 includes a first refrigerant flow path 51, and the high-temperature compressor 2, the intermediate cooler 3 and the first refrigerant flow path 51 of the refrigeration evaporator 5 form a second-stage refrigeration flow path for refrigerating a refrigeration area in which the refrigeration evaporator 5 is located. The refrigeration evaporator 5 can further include a second refrigerant flow path 52, and the double-stage refrigeration system further includes a first-stage inter-refrigerant branch 6 and a second-stage inter-refrigerant branch 7. The high-temperature compressor 2, the first-stage inter-refrigerant branch 6, the second refrigerant flow path 52 of the refrigeration evaporator 5 and the second-stage inter-refrigerant branch 7 form an inter-stage refrigeration flow path for refrigerating the refrigeration area.

[0050] That is, in the double-stage refrigeration system in this embodiment, two refrigeration flow paths for refrigerating the refrigeration area are provided, i.e., the second-stage refrigeration flow path and the inter-stage refrigeration flow path. Based on this, the embodiment can select the different refrigeration flow paths to refrigerate the refrigeration area according to different requirements.

[0051] The refrigeration control method includes:

[0052] S110, determining whether the freezing area and the refrigeration area have refrigeration requirements;

[0053] S120, in the case that the freezing area and the refrigeration area both have refrigeration requirements, controlling the first-stage refrigeration flow path to refrigerate the freezing area, and selecting the second-stage refrigeration flow path or the inter-stage refrigeration flow path to refrigerate the refrigeration area according to a refrigeration priority mode of the freezing area and the refrigeration area;

[0054] S130, in the case that the freezing area does not have refrigeration requirements and the refrigeration area has refrigeration requirements, controlling the second-stage refrigeration flow path to refrigerate the refrigeration area;

[0055] S140, in the case that the freezing area has refrigeration requirements and the refrigeration area does not have refrigeration requirements, controlling the first-stage refrigeration flow path to refrigerate the freezing area.

[0056] In step S110, the freezing area can be provided with a freezing target temperature, and the refrigeration area can be provided with a refrigeration target temperature. The freezing target temperature and the refrigeration target temperature can be set according to actual requirements, and their specific values are not limited.

[0057] In this step, for the freezing zone, the measured temperature of the freezing zone can be detected by the temperature sensor of the freezing zone. If the measured temperature of the freezing zone is higher than the freezing target temperature, it is determined that the freezing zone has a refrigeration demand. If the measured temperature of the freezing zone is not higher than the freezing target temperature, it is determined that the freezing zone does not have a refrigeration demand. For the refrigerating zone, the measured temperature of the refrigerating zone can be detected by the temperature sensor of the refrigerating zone. If the measured temperature of the refrigerating zone is higher than the refrigerating target temperature, it is determined that the refrigerating zone has a refrigeration demand. If the measured temperature of the refrigerating zone is not higher than the refrigerating target temperature, it is determined that the refrigerating zone does not have a refrigeration demand.

[0058] For example, the freezing target temperature can be -18℃, and the refrigerating target temperature can be 0℃. If the temperature sensor of the freezing zone detects that the measured temperature of the freezing zone is higher than -18℃, and the temperature sensor of the refrigerating zone detects that the measured temperature of the refrigerating zone is higher than 0℃, it is determined that both the freezing zone and the refrigerating zone have a refrigeration demand. If the temperature sensor of the freezing zone detects that the measured temperature of the freezing zone is higher than -18℃, and the temperature sensor of the refrigerating zone detects that the measured temperature of the refrigerating zone is not higher than 0℃, it is determined that the freezing zone has a refrigeration demand and the refrigerating zone does not have a refrigeration demand. If the temperature sensor of the freezing zone detects that the measured temperature of the freezing zone is not higher than -18℃, and the temperature sensor of the refrigerating zone detects that the measured temperature of the refrigerating zone is higher than 0℃, it is determined that the freezing zone does not have a refrigeration demand and the refrigerating zone has a refrigeration demand. If the temperature sensor of the freezing zone detects that the measured temperature of the freezing zone is not higher than -18℃, and the temperature sensor of the refrigerating zone detects that the measured temperature of the refrigerating zone is not higher than 0℃, it is determined that both the freezing zone and the refrigerating zone do not have a refrigeration demand.

[0059] Of course, a temperature fluctuation range can also be set. When the difference between the measured temperature detected by the temperature sensor and the target temperature of the corresponding zone is within the allowed fluctuation range, it can be considered that the corresponding zone does not have a refrigeration demand. When the temperature value of the measured temperature detected by the temperature sensor exceeds the allowed fluctuation range from the target temperature of the corresponding zone, it can be considered that the corresponding zone has a refrigeration demand.

[0060] It should be noted that, in addition to detecting the temperature to determine whether the freezing zone and the refrigerating zone have a refrigeration demand, other methods can also be used, which are not limited.

[0061] In step S120, when both the freezing zone and the refrigerating zone have a refrigeration demand, the two-stage refrigeration system needs to be controlled to refrigerate the freezing zone and the refrigerating zone at the same time. In this case, the first-stage refrigeration flow path can be controlled to be in an operating state, i.e., both the low-temperature compressor 1 and the high-temperature compressor 2 are in an operating state, so as to refrigerate the freezing zone through the first-stage refrigeration flow path. At the same time, the refrigeration priority mode of the freezing zone and the refrigerating zone can be determined, and then the second-stage refrigeration flow path or the inter-stage refrigeration flow path is selected to refrigerate the refrigerating zone according to the determination result.

[0062] The refrigeration priority mode of the freezing zone and the refrigeration priority mode of the refrigerating zone can be divided into a freezing priority mode and a refrigerating priority mode. The freezing priority mode means that the refrigeration demand of the freezing zone needs to be ensured first, and then the refrigeration demand of the refrigerating zone is ensured. The refrigerating priority mode means that the refrigeration demand of the refrigerating zone needs to be ensured first, and then the refrigeration demand of the freezing zone is ensured.

[0063] If it is determined that the refrigeration priority mode of the freezing zone and the refrigeration priority mode of the refrigerating zone are the freezing priority mode, the inter-stage refrigeration flow path can be controlled to refrigerate the refrigerating zone. At this time, the second-stage refrigeration flow path can be controlled to be in a closed state, and the inter-stage refrigeration flow path is controlled to be in a running state. The inter-stage refrigeration flow path is composed of the high-temperature compressor 2, the first inter-stage refrigerant branch 6, the second refrigerant flow path 52 of the refrigerating evaporator 5, and the second inter-stage refrigerant branch 7. The refrigerant flow path is independent of the low-temperature compressor 1 in the first-stage refrigeration flow path, so that the refrigeration of the refrigerating zone does not need to rely on the linkage between the intermediate cooler 3 and the low-temperature compressor 1 in the second-stage refrigeration flow path, thereby avoiding the decline of the operating efficiency of the low-temperature compressor 1 due to the temperature adjustment of the intermediate cooler 3 being biased towards the refrigerating demand, and also avoiding the high operating energy consumption of the low-temperature compressor 1 due to the temperature adjustment of the intermediate cooler 3 being biased towards the freezing demand. This embodiment can ensure that the intermediate temperature required for the refrigeration of the freezing zone remains in the best state by using the inter-stage refrigeration flow path in the freezing priority mode, and at the same time, the refrigeration of the refrigerating zone is driven by the high-temperature compressor 2 alone, which not only meets the energy efficiency demand of the freezing priority, but also takes into account the refrigeration demand of the refrigerating zone, and finally realizes the energy consumption optimization of the two-stage refrigeration system in the freezing priority mode.

[0064] It should be noted that when the inter-stage refrigeration flow path is used for refrigerating the refrigerating zone, the refrigerant driven by the high-temperature compressor 2 flows through the first inter-stage refrigerant branch 6, the second refrigerant flow path 52 of the refrigerating evaporator 5, and the second inter-stage refrigerant branch 7 in sequence to form an independent circulation. In this process, the first throttling valve 11 of the first inter-stage refrigerant branch 6 can reduce the pressure of the refrigerant to the saturation pressure corresponding to the refrigerating evaporation temperature. The second refrigerant flow path 52 returns to the high-temperature compressor 2 through the second inter-stage refrigerant branch 7 after absorbing heat in the refrigerating evaporator 5. Since this circulation is completely independent of the low-temperature compressor 1 and the intermediate cooler 3, the temperature of the intermediate cooler 3 can be maintained in a better temperature range, so that the low-temperature compressor 1 and the high-temperature compressor 2 can maintain a high energy efficiency ratio when driving the refrigeration of the freezing zone. At the same time, the refrigeration demand of the refrigerating zone is satisfied through an independent circulation path, avoiding the temperature compromise problem caused by sharing the intermediate cooler 3 in the traditional scheme. This embodiment can realize the optimization of the overall energy consumption of the two-stage refrigeration system in the freezing priority mode through flow path isolation.

[0065] In the refrigeration priority mode, if the interstage refrigeration flow path continues to be used to refrigerate the refrigeration zone, the refrigeration efficiency of the refrigeration zone may be limited because the interstage refrigeration flow path needs to draw refrigerant from the high-temperature compressor 2. This may not be able to fully match the rapid cooling requirements in the refrigeration priority mode. At the same time, the coupling relationship between the interstage refrigeration flow path and the first-stage refrigeration flow path may affect the optimal adjustment of the intermediate temperature of the two-stage refrigeration system.

[0066] Based on this, in this embodiment, if the refrigeration priority mode between the freezing zone and the refrigeration zone is determined to be the refrigeration priority mode, then the second-stage refrigeration flow path is controlled to refrigerate the refrigeration zone. At this time, the interstage refrigeration flow path can be controlled to be in a closed state, while the second-stage refrigeration flow path is controlled to be in an operating state. The second-stage refrigeration flow path may include a high-temperature compressor 2, an intercooler 3, and a first refrigerant flow path 51 for the refrigeration evaporator 5, etc. Meanwhile, the first-stage refrigeration flow path is also in an operating state, and it may include a low-temperature compressor 1, an intercooler 3, a high-temperature compressor 2, and a refrigeration evaporator 4, etc. In this case, the low-temperature compressor 1, the high-temperature compressor 2, and the intercooler 3 cooperate with each other to better prioritize the refrigeration needs of the refrigeration zone.

[0067] In this embodiment, when both the freezing and refrigeration zones have refrigeration needs, the second-stage refrigeration path and the interstage refrigeration path can be selected to refrigerate the refrigeration zone according to the refrigeration priority mode of the freezing and refrigeration zones. When it is necessary to prioritize the refrigeration effect of the freezing zone, the refrigeration zone can be refrigerated through the interstage refrigeration path. That is, the medium-temperature refrigerant discharged from the high-temperature compressor 2 is directly diverted to the second refrigerant path 52 of the refrigeration evaporator 5, avoiding the temperature of the intercooler 3 being raised by the demand of the refrigeration zone, thereby maintaining the optimal intermediate temperature of the two-stage compression. When the refrigeration zone needs to be refrigerated first, the second-stage refrigeration path driven solely by the high-temperature compressor 2 can be switched to better ensure the refrigeration needs of the refrigeration zone. That is, the dynamic path selection mechanism of this embodiment, by coordinating the refrigerant distribution of the two-stage compression, satisfies the high refrigeration demand of the freezing zone when the freezing and refrigeration zones are refrigerated simultaneously, and also reduces the ineffective power consumption of the low-temperature compressor 1 through intermediate temperature optimization. This allows the two-stage refrigeration system to achieve energy-saving goals while meeting the refrigeration demand, reducing the energy consumption of the entire two-stage refrigeration system and improving the user experience.

[0068] In one exemplary embodiment, reference Figure 1 and Figure 3 As shown, a two-stage refrigeration system is provided, along with a refrigeration device including the aforementioned two-stage refrigeration system, and a refrigeration control method applied to the two-stage refrigeration system, wherein the two-stage refrigeration system is used to implement the aforementioned refrigeration control method. In this embodiment, when both the freezing zone and the refrigeration zone have refrigeration needs, a refrigeration priority mode for the freezing zone and the refrigeration zone can be determined based on the load ratio of the freezing zone and the refrigeration zone.

[0069] The refrigeration control method can comprise:

[0070] S210, determining a freezing load of the freezing area and a refrigerating load of the refrigerating area;

[0071] S220, determining a load ratio of the freezing area and the refrigerating area based on the freezing load and the refrigerating load;

[0072] S230, judging the size of the load ratio of the freezing area and the refrigerating area and a load ratio limit value;

[0073] S240, if it is determined that the load ratio between the freezing area and the refrigerating area is greater than or equal to the load ratio limit value, determining that the refrigeration priority mode of the freezing area and the refrigerating area is a freezing priority mode;

[0074] S250, if it is determined that the load ratio between the freezing area and the refrigerating area is less than the load ratio limit value, determining that the refrigeration priority mode of the freezing area and the refrigerating area is a refrigerating priority mode.

[0075] In step S210, for the freezing load, the measured temperature of the freezing area can be detected by a temperature sensor of the freezing area, denoted as freezing measured temperature, and then the freezing target temperature is subtracted from the freezing measured temperature to obtain the freezing load. For the refrigerating load, the measured temperature of the refrigerating area can be detected by a temperature sensor of the refrigerating area, denoted as refrigerating measured temperature, and then the refrigerating target temperature is subtracted from the refrigerating measured temperature to obtain the refrigerating load.

[0076] It should be noted that in addition to determining the freezing load and the refrigerating load by the above method, other methods can also be used, which are not limited.

[0077] In step S220, after obtaining the freezing load and the refrigerating load at the same time, the ratio of the freezing load to the refrigerating load (i.e. freezing load / refrigerating load) can be determined as the load ratio of the freezing area and the refrigerating area. The load ratio can reflect the priority degree of the refrigeration demand of the freezing area and the refrigerating area.

[0078] In step S230, the refrigeration device can store a load ratio limit value, which can be set according to actual needs, and the specific value is not limited. For example, the load ratio limit value can be 1.

[0079] After obtaining the load ratio of the freezing area and the refrigerating area, the size of the load ratio and the load ratio limit value can be compared to determine the refrigeration priority mode.

[0080] In step S240, if it is determined that the load ratio between the freezing zone and the refrigeration zone is greater than or equal to the load ratio limit value, it indicates that the refrigeration demand of the freezing zone is more urgent than that of the refrigeration zone, and the refrigeration priority mode of the freezing zone and the refrigeration zone can be determined as the freezing priority mode, so as to control the dual-stage refrigeration system to preferentially ensure the refrigeration of the freezing zone. At this time, the inter-stage refrigeration flow path and the first-stage refrigeration flow path are both in the running state, and the second-stage refrigeration flow path is in the closed state. The dual-stage refrigeration system uses the inter-stage refrigeration flow path to refrigerate the refrigeration zone, and uses the first-stage refrigeration flow path to refrigerate the freezing zone, so as to preferentially ensure the refrigeration of the freezing zone, and can avoid the over-high energy consumption of the low-temperature compressor 1 and reduce the energy consumption of the entire dual-stage refrigeration system.

[0081] In step S250, if it is determined that the load ratio between the freezing zone and the refrigeration zone is less than the load ratio limit value, it indicates that the refrigeration demand of the refrigeration zone is more urgent than that of the freezing zone, and the refrigeration priority mode of the freezing zone and the refrigeration zone can be determined as the refrigeration priority mode, so as to control the dual-stage refrigeration system to preferentially ensure the refrigeration of the refrigeration zone. At this time, the inter-stage refrigeration flow path is in the closed state, and the first-stage refrigeration flow path and the second-stage refrigeration flow path are both in the running state. The dual-stage refrigeration system uses the first-stage refrigeration flow path to refrigerate the freezing zone, and uses the second-stage refrigeration flow path to refrigerate the refrigeration zone, so as to preferentially ensure the refrigeration of the refrigeration zone and better meet the refrigeration demand of the user.

[0082] In this embodiment, the load ratio is quantified by the ratio of the freezing load and the refrigeration load, which can more intuitively and accurately reflect the urgency of the refrigeration demand of the two zones, so that the refrigeration resources (cooling capacity, compressor power) can be accurately distributed to the zone that needs it most, and the problem of over-high energy consumption can be avoided. Moreover, the calculation of the load ratio is based on the real-time data of the temperature sensor (the difference between the measured temperature and the target temperature), without complex working condition modeling and manual intervention, and the determination result can be quickly output. At the same time, the comparison between the calculated load ratio and the load ratio limit value can directly trigger the selection of the corresponding flow path, which can avoid the complex regulation process of multiple parameter coupling, better ensure that the dual-stage refrigeration system can respond to the temperature changes of the two zones in real time, reduce the temperature fluctuations caused by lagging judgment, improve the stability of the temperature control of the cold storage, and better solve the energy consumption.

[0083] In one exemplary embodiment, referring to Figures 1 to 3 As shown in the figure, a dual-stage refrigeration system is provided, as well as a refrigeration equipment comprising the above-mentioned dual-stage refrigeration system, and a refrigeration control method applied to the dual-stage refrigeration system, i.e. the dual-stage refrigeration system is used to implement the above-mentioned refrigeration control method. In this embodiment, the dual-stage refrigeration system comprises a low-temperature compressor 1, a high-temperature compressor 2, an intermediate cooler 3, a refrigeration evaporator 5 and a freezing evaporator 4, and can further comprise a condenser, a first inter-stage refrigerant branch 6 and a second inter-stage refrigerant branch 7.

[0084] The intermediate cooler 3 can be a flash tank. The outlet branch of the low-temperature compressor 1 extends below the liquid level in the intermediate cooler 3 to achieve communication between the outlet of the low-temperature compressor 1 and the intermediate cooler 3. The inlet of the low-temperature compressor 1 is in communication with the outlet of the freezing evaporator 4. The inlet of the freezing evaporator 4 is in communication with the outlet of the intermediate cooler 3 via a first freezing branch to achieve communication between the freezing evaporator 4 and the intermediate cooler 3, and the first freezing branch can be provided with a third throttling valve 13. The outlet of the high-temperature compressor 2 is in communication with the inlet of the condenser, and the outlet of the condenser is in communication with the intermediate cooler 3 via a second freezing branch. The second freezing branch is provided with a second throttling valve 12. In this way, the low-temperature compressor 1, the high-temperature compressor 2, the intermediate cooler 3, and the freezing evaporator 4 form the entire first-stage refrigeration flow path.

[0085] The inlet of the first refrigerant flow path 51 of the refrigerating evaporator 5 is in communication with the outlet of the intermediate cooler 3 via a first refrigerating branch, and the outlet of the first refrigerant flow path 51 is in communication with the inlet of the intermediate cooler 3 via a second refrigerating branch. The first refrigerating branch can be provided with a refrigerant pump 15 (also referred to as a refrigerant pump) to drive the circulation of refrigerant between the intermediate cooler 3 and the first refrigerant flow path 51, and then the refrigerant circulation flow path formed by the high-temperature compressor 2 and the intermediate cooler 3 forms a complete second-stage refrigeration flow path.

[0086] The outlet of the high-temperature compressor 2 is in communication with the inlet of the condenser, the outlet of the condenser is in communication with the inlet of the second refrigerant flow path 52 of the refrigerating evaporator 5 via a first inter-stage refrigerant branch 6, and the outlet of the second refrigerant flow path 52 is in communication with the inlet of the high-temperature compressor 2 via a second inter-stage refrigerant branch 7. In this way, the high-temperature compressor 2, the condenser, and the second refrigerant flow path 52 form the inter-stage refrigeration flow path. The first inter-stage refrigerant branch 6 can include a first throttling valve 11, and the first inter-stage refrigerant branch 6 and / or the second inter-stage refrigerant branch 7 can include a solenoid valve 14. In this embodiment, the state of the solenoid valve 14 can be controlled to control the inter-stage refrigeration flow path to be in an operating state or a closed state.

[0087] The temperature sensor of the freezing zone can periodically or in real time detect the measured temperature of the freezing zone (denoted as freezing measured temperature), and the temperature sensor of the refrigerating zone can synchronously detect the measured temperature of the refrigerating zone (denoted as refrigerating measured temperature) with the temperature sensor of the freezing zone. Then, whether the freezing zone has a refrigeration requirement is determined based on the freezing measured temperature and the freezing target temperature, and whether the refrigerating zone has a refrigeration requirement is determined based on the refrigerating measured temperature and the refrigerating target temperature.

[0088] When the refrigeration demand is in the freezing zone and no refrigeration demand is in the refrigerating zone, the first stage refrigeration flow path is controlled to be in the running state, and the second stage refrigeration flow path and the inter-stage refrigeration flow path are both controlled to be in the closed state. That is, referring to Table 1, the low-temperature compressor 1, the high-temperature compressor 2, the third throttling valve 13 and the second throttling valve 12 are opened, and the refrigerant pump 15, the first throttling valve 11 and the electromagnetic valve 14 are closed. In this case, the low-temperature compressor 1 compresses the refrigerant to the target intermediate pressure (the target intermediate pressure can be calculated according to different evaporation / condensation temperatures, and the target intermediate pressure is not described here), and then the exhaust gas is discharged to the intermediate cooler 3 for cooling. The high-temperature compressor 2 absorbs the saturated gas in the intermediate cooler 3, and then the exhaust gas is discharged to the condenser after being compressed. After throttling through the second throttling valve 12, the refrigerant is transmitted to the intermediate cooler 3. The saturated liquid is transmitted to the freezing evaporator 4 after throttling through the third throttling valve 13, so as to realize the refrigeration of the freezing zone.

[0089] Table 1

[0090]

[0091] When the refrigeration demand is in the freezing zone and no refrigeration demand is in the refrigerating zone, the first stage refrigeration flow path is controlled to be in the running state, and the second stage refrigeration flow path and the inter-stage refrigeration flow path are both controlled to be in the closed state. That is, referring to Table 1, the low-temperature compressor 1, the high-temperature compressor 2, the third throttling valve 13 and the second throttling valve 12 are opened, and the refrigerant pump 15, the first throttling valve 11 and the electromagnetic valve 14 are closed. In this case, the low-temperature compressor 1 compresses the refrigerant to the target intermediate pressure (the target intermediate pressure can be calculated according to different evaporation / condensation temperatures, and the target intermediate pressure is not described here), and then the exhaust gas is discharged to the intermediate cooler 3 for cooling. The high-temperature compressor 2 absorbs the saturated gas in the intermediate cooler 3, and then the exhaust gas is discharged to the condenser after being compressed. After throttling through the second throttling valve 12, the refrigerant is transmitted to the intermediate cooler 3. The saturated liquid is transmitted to the freezing evaporator 4 after throttling through the third throttling valve 13, so as to realize the refrigeration of the freezing zone.

[0092] Table 2

[0093]

[0094] When the refrigeration demand is in the freezing zone and no refrigeration demand is in the refrigerating zone, the first stage refrigeration flow path is controlled to be in the running state, and the second stage refrigeration flow path and the inter-stage refrigeration flow path are both controlled to be in the closed state. That is, referring to Table 1, the low-temperature compressor 1, the high-temperature compressor 2, the third throttling valve 13 and the second throttling valve 12 are opened, and the refrigerant pump 15, the first throttling valve 11 and the electromagnetic valve 14 are closed. In this case, the low-temperature compressor 1 compresses the refrigerant to the target intermediate pressure (the target intermediate pressure can be calculated according to different evaporation / condensation temperatures, and the target intermediate pressure is not described here), and then the exhaust gas is discharged to the intermediate cooler 3 for cooling. The high-temperature compressor 2 absorbs the saturated gas in the intermediate cooler 3, and then the exhaust gas is discharged to the condenser after being compressed. After throttling through the second throttling valve 12, the refrigerant is transmitted to the intermediate cooler 3. The saturated liquid is transmitted to the freezing evaporator 4 after throttling through the third throttling valve 13, so as to realize the refrigeration of the freezing zone.

[0095] The freezing load = the freezing actual temperature - the freezing target temperature;

[0096] The refrigerating load = the refrigerating actual temperature - the refrigerating target temperature;

[0097] The load ratio of the freezing warehouse to the refrigerating warehouse = the freezing load / the refrigerating load.

[0098] Wherein, according to the load ratio of the freezing zone and the refrigeration zone, the following modes are divided:

[0099] When the load ratio of the freezing zone and the refrigeration zone is greater than or equal to the load ratio limit value, the freezing priority mode is determined, in which mode, the first stage refrigeration flow path and the inter-stage refrigeration flow path are both controlled to be in the running state, and the second stage refrigeration flow path is controlled to be in the closed state. That is, referring to Table 3, the low-temperature compressor 1, the high-temperature compressor 2, the second throttle valve 12 and the third throttle valve 13 are turned on, and the first throttle valve 11 and the electromagnetic valve 14 are also turned on, and the refrigerant pump 15 is turned off. The low-temperature compressor 1 compresses the refrigerant to the target intermediate pressure, and then discharges the exhaust to the intermediate cooler 3 for cooling. The high-temperature compressor 2 absorbs the saturated gas in the intermediate cooler 3, and then discharges the exhaust to the condenser after compression. Then, after throttling through the first throttle valve 11, the refrigerant is transmitted to the intermediate cooler 3. The saturated liquid in the intermediate cooler 3 is discharged to the freezing evaporator 4 after throttling through the third throttle valve 13, thereby realizing refrigeration for the freezing zone. At the same time, part of the refrigerant discharged from the condenser is transmitted to the second refrigerant flow path 52 of the refrigeration evaporator 5 after throttling through the first throttle valve 11, thereby absorbing the heat of the refrigeration zone and realizing refrigeration for the refrigeration zone. The refrigerant in the second refrigerant flow path 52 absorbs heat and then returns to the high-temperature compressor 2 to participate in the next refrigeration cycle.

[0100] Table 3

[0101]

[0102] When the load ratio of the freezing zone and the refrigeration zone is less than the load ratio limit value, the refrigeration priority mode is determined, in which mode, the first stage refrigeration flow path and the second stage refrigeration flow path are both controlled to be in the running state, and the inter-stage refrigeration flow path is controlled to be in the closed state. That is, referring to Table 4, the low-temperature compressor 1, the high-temperature compressor 2, the second throttle valve 12, the third throttle valve 13 and the refrigerant pump 15 are turned on, and the first throttle valve 11 and the electromagnetic valve 14 are turned off. The low-temperature compressor 1 compresses the refrigerant to the target evaporation pressure required by the refrigeration zone, and then discharges the exhaust to the intermediate cooler 3 for cooling. The refrigerant pump 15 is turned on to supply liquid to the refrigeration evaporator 5. The refrigerant absorbs the heat of the refrigeration zone in the refrigeration evaporator 5, and then returns to the intermediate cooler 3 for gas-liquid separation. The high-temperature compressor 2 absorbs the exhaust of the low-temperature compressor 1 and the gas separated in the intermediate cooler 3 after evaporation in the refrigeration evaporator 5, and then discharges the exhaust to the condenser after compression. Then, after throttling through the second throttle valve 12, the refrigerant is transmitted to the intermediate cooler 3. The saturated liquid in the intermediate cooler 3 is discharged to the freezing evaporator 4 after throttling through the third throttle valve 13, thereby realizing refrigeration for the freezing zone.

[0103] Table 4

[0104]

[0105] In this embodiment, when both the freezing zone and the refrigeration zone have refrigeration requirements, the second-stage refrigeration flow path and the inter-stage refrigeration flow path can be selected according to the refrigeration priority mode of the freezing zone and the refrigeration zone to refrigerate the refrigeration zone. When it is necessary to prioritize the refrigeration effect of the freezing zone, the inter-stage refrigeration flow path can be used to refrigerate the refrigeration zone, i.e., the medium-temperature refrigerant discharged by the high-temperature compressor 2 is directly split to the second refrigerant flow path 52 of the refrigeration evaporator 5, so as to avoid the temperature of the intercooler 3 being raised by the refrigeration zone requirement, thereby maintaining the optimal intermediate temperature of the two-stage compression; when the refrigeration zone needs to be prioritized, the second-stage refrigeration flow path driven by the high-temperature compressor 2 alone can be switched to, so as to better ensure the refrigeration requirement of the refrigeration zone.

[0106] In this embodiment, the appropriate refrigeration flow path is automatically selected to refrigerate the refrigeration zone according to the load ratio of the freezing zone and the refrigeration zone, the adaptive adjustment of the target intermediate temperature can be realized, and when the freezing zone and the refrigeration zone are refrigerated at the same time, the high refrigeration requirement of the freezing zone can be met, and the invalid power consumption of the low-temperature compressor 1 can be reduced through intermediate temperature optimization, so that the two-stage refrigeration system meets the refrigeration requirement and achieves the energy-saving goal, the energy consumption of the entire two-stage refrigeration system is reduced, and the user experience is improved.

[0107] Those skilled in the art will further appreciate that the units and algorithm steps of the examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described generally in terms of their functionality in the above description. Whether such functionality is implemented as hardware or software depends on the particular application and design constraints imposed on the overall system. Those skilled in the art can implement the described functionality in varying ways for each particular application, but such implementation should not be interpreted as a departure from the scope of the present application.

[0108] It should be noted that the terms "one embodiment", "an embodiment", "example embodiment", "some embodiments", etc. in the specification mean that the described embodiment can include a particular feature, structure, or characteristic, but every embodiment can not necessarily include the particular feature, structure, or characteristic. In addition, such terms do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments whether explicitly described or not.

[0109] It has to be noted that, in the present document, relational terms are intended only to convey a possible relationship between elements or items or between the operations that are described, and such a relationship can or can not exist, but is not necessarily implied, in accordance with the specific context. In particular, a relationship can exist even though two elements or operations are not directly connected. Furthermore, the terms "comprise", "comprising", "include", "including", "contain", "containing", or any other any other variant are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or even inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a", "comprising... a", "includes... a", "including... a", "contains... a", "containing... a" does not, without further constraints, foreclose the existence of additional identical elements.

[0110] The above embodiments are only preferred embodiments of the present application, but the protection scope of the present application is not limited thereto. Any equivalent replacement or transformation of the present application made by those skilled in the art based on the present application shall fall within the protection scope of the present application.

Claims

1. A refrigeration control method, characterized in that, The refrigeration control method is applied to a two-stage refrigeration system, which includes a low-temperature compressor, a high-temperature compressor, an intercooler, a refrigeration evaporator, and a freezing evaporator. The refrigeration evaporator includes a first refrigerant flow path and a second refrigerant flow path. The low-temperature compressor, the high-temperature compressor, the intercooler, and the freezing evaporator form a first-stage refrigeration flow path, which is used to refrigerate the freezing zone where the freezing evaporator is located. The first refrigerant flow path in the high-temperature compressor, the intercooler, and the refrigeration evaporator forms a second-stage refrigeration flow path, which is used to refrigerate the refrigeration zone where the refrigeration evaporator is located. The two-stage refrigeration system also includes a first-stage inter-stage refrigerant branch and a second-stage inter-stage refrigerant branch. The high-temperature compressor, the first-stage inter-stage refrigerant branch, the second refrigerant flow path of the refrigeration evaporator, and the second-stage inter-stage refrigerant branch form an inter-stage refrigeration flow path, which is used to refrigerate the refrigeration zone. The refrigeration control method includes: When both the freezing zone and the refrigeration zone have refrigeration requirements, the first-stage refrigeration flow path is controlled to refrigerate the freezing zone, and the second-stage refrigeration flow path or the inter-stage refrigeration flow path is selected to refrigerate the refrigeration zone according to the refrigeration priority mode between the freezing zone and the refrigeration zone.

2. The refrigeration control method according to claim 1, characterized in that, The step of selecting the second-stage refrigeration flow path or the inter-stage refrigeration flow path for refrigerating the refrigeration zone based on the refrigeration priority mode between the freezing zone and the refrigeration zone includes: If the refrigeration priority mode between the freezing zone and the refrigeration zone is determined to be the freezing priority mode, then the interstage refrigeration flow path is controlled to refrigerate the refrigeration zone.

3. The refrigeration control method according to claim 2, characterized in that, The step of selecting the second-stage refrigeration flow path or the inter-stage refrigeration flow path for refrigerating the refrigeration zone based on the refrigeration priority mode between the freezing zone and the refrigeration zone includes: If the refrigeration priority mode between the freezing zone and the refrigeration zone is determined to be the refrigeration priority mode, then the second-stage refrigeration flow path is controlled to refrigerate the refrigeration zone.

4. The refrigeration control method according to claim 3, characterized in that, The refrigeration control method includes: When both the freezing zone and the refrigeration zone have refrigeration requirements, a refrigeration priority mode for the freezing zone and the refrigeration zone is determined based on the load ratio between the freezing zone and the refrigeration zone.

5. The refrigeration control method according to claim 4, characterized in that, The step of determining the refrigeration priority mode for the freezing zone and the refrigeration zone based on the load ratio between the freezing zone and the refrigeration zone includes: If the load ratio between the freezing zone and the refrigeration zone is determined to be greater than or equal to the load ratio limit, then the refrigeration priority mode for the freezing zone and the refrigeration zone is determined to be the freezing priority mode.

6. The refrigeration control method according to claim 4, characterized in that, The step of determining the refrigeration priority mode for the freezing zone and the refrigeration zone based on the load ratio between the freezing zone and the refrigeration zone includes: If it is determined that the load ratio between the freezing zone and the refrigeration zone is less than the load ratio limit, then the refrigeration priority mode between the freezing zone and the refrigeration zone is determined to be the refrigeration priority mode.

7. The refrigeration control method according to any one of claims 1-6, characterized in that, The refrigeration control method includes: When the freezing zone does not require refrigeration but the refrigeration zone does require refrigeration, the second-stage refrigeration flow path is controlled to refrigerate the refrigeration zone.

8. The refrigeration control method according to any one of claims 1-6, characterized in that, The refrigeration control method includes: When the freezing zone has a refrigeration requirement and the refrigeration zone does not have a refrigeration requirement, the first-stage refrigeration flow path is controlled to refrigerate the freezing zone.

9. A two-stage refrigeration system, characterized in that, The two-stage refrigeration system includes a low-temperature compressor, a high-temperature compressor, an intercooler, a refrigeration evaporator, and a freezing evaporator; the refrigeration evaporator includes a first refrigerant flow path and a second refrigerant flow path. The low-temperature compressor, the high-temperature compressor, the intercooler, and the evaporator for refrigeration form a first-stage refrigeration flow path, which is used to refrigerate the refrigeration zone where the evaporator for refrigeration is located. The first refrigerant flow path in the high-temperature compressor, the intercooler, and the evaporator for refrigeration forms a second-stage refrigeration flow path, which is used to refrigerate the refrigeration zone where the evaporator for refrigeration is located. The two-stage refrigeration system further includes a first-stage refrigerant branch and a second-stage refrigerant branch. The high-temperature compressor, the first-stage refrigerant branch, the second refrigerant flow path of the refrigeration evaporator, and the second-stage refrigerant branch form an interstage refrigeration flow path, which is used to refrigerate the refrigeration zone. In the two-stage refrigeration system, when both the freezing zone and the refrigeration zone have refrigeration needs, the first-stage refrigeration flow path is controlled to refrigerate the freezing zone, and the second-stage refrigeration flow path or the inter-stage refrigeration flow path is selected to refrigerate the refrigeration zone according to the refrigeration priority mode between the freezing zone and the refrigeration zone.

10. The two-stage refrigeration system according to claim 9, characterized in that, The two-stage refrigeration system includes a condenser, and the first interstage refrigerant branch includes a first throttling valve. In the interstage refrigeration flow path, the first interstage refrigerant branch is located between the condenser and the second refrigerant flow path.

11. The two-stage refrigeration system according to claim 9 or 10, characterized in that, The first-stage refrigerant branch and / or the second-stage refrigerant branch include solenoid valves.

12. A refrigeration device, characterized in that, The refrigeration equipment includes the two-stage refrigeration system as described in any one of claims 9-11.

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