Cascade refrigeration system and refrigeration equipment

Abstract

The utility model relates to the technical field of refrigeration, and discloses a cascade refrigeration system which comprises a high-temperature-stage circulation loop, a low-temperature-stage circulation loop and a refrigeration loop. The low-temperature-stage circulation loop comprises a low-temperature-stage compressor, a precooler, a condensation part of the evaporative condenser, a low-temperature-stage throttling element and a low-temperature-stage evaporator which are sequentially connected to the same loop; a low-temperature stage heat regenerator; and the drying filter is arranged on a pipeline, between the precooler and the low-temperature throttling element, of the low-temperature-stage circulation loop and used for drying and filtering the flowing low-temperature-stage refrigerant medium. According to the cascade refrigeration system, the precooler and the heat regenerator are arranged in the low-temperature-stage circulation loop, and the drying filter is arranged between the precooler and the low-temperature-stage throttling element, so that the actual filtering and purifying effect of the drying filter is improved by adjusting the position of the drying filter relative to other components of the low-temperature-stage circulation loop. The utility model further discloses the refrigeration equipment.

Description

Technical Field

[0001] The present application relates to the field of refrigeration technology, for example, to a cascade refrigeration system and refrigeration equipment. Background Art

[0002] The cascade refrigeration system is a new type of refrigeration technology. This system uses two or more refrigerants and two or more single-stage (or two-stage) compression refrigeration cycle systems to achieve efficient refrigeration. Compared with traditional refrigeration systems, cascade refrigeration is generally used for low-temperature equipment at -60 to -120°C, such as ultra-low temperature cold storage, rapid freezing process equipment, cryogenic boxes, etc. It can greatly broaden the system refrigeration temperature range while ensuring work efficiency.

[0003] The structure of a common cascade refrigeration system can be divided into a high-temperature stage and a low-temperature stage. The high-temperature stage and the low-temperature stage each constitute a complete refrigeration cycle. The high-temperature stage uses a medium-temperature refrigerant, and the low-temperature stage uses a low-temperature refrigerant. The refrigerant in the high-temperature stage evaporates to condense the refrigerant in the low-temperature stage. The two parts are connected to form a whole using the same evaporative condenser. The cold energy can be transferred from the high-temperature stage to the low-temperature stage, so that the low-temperature stage can reach a lower refrigeration temperature.

[0004] In the process of implementing the embodiments of the present disclosure, it is found that there are at least the following problems in the related art:

[0005] There are often impurities mixed in the refrigeration cycle, such as solid impurities such as metal chips, oxides, dust, or liquid impurities such as residual moisture. The presence of these impurities will affect the actual operating performance of the refrigeration system. In view of the above situation, the cascade refrigeration system will set a dry filter in the refrigeration cycle to filter these impurities; but in actual application, it is found that since most impurities are mixed in the refrigerant, the phase state, temperature, pressure and other parameters of the refrigerant will change when it flows through different parts of the refrigeration cycle, which will also affect the actual filtering effect. Therefore, how to configure the relative position of the dry filter and other components is crucial to ensure the filtering performance of the dry filter.

[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present application, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Utility Model Content

[0007] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical elements or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0008] The embodiments of the present disclosure provide a cascade refrigeration system and a refrigeration device to solve the technical problems in the related art such as the configuration of the drying filter and other components of the cascade refrigeration system resulting in poor actual filtering effect.

[0009] According to an embodiment of the first aspect of the present application, a cascade refrigeration system is provided, comprising:

[0010] A high temperature stage circulation loop, comprising a high temperature stage compressor, a high temperature stage condenser, and an evaporation portion of the evaporative condenser, which are sequentially connected to the same loop;

[0011] A low temperature circulation loop, comprising a low temperature compressor, a precooler, a condensing part of an evaporative condenser, a low temperature throttling device and a low temperature evaporator, which are sequentially connected to the same loop;

[0012] A low-temperature heat regenerator, comprising a first heat regenerator and a second heat regenerator capable of exchanging heat with each other, wherein the first heat regenerator is connected to a pipeline between a precooler and an evaporative condenser of a low-temperature circulation loop, and the second heat regenerator is connected to a pipeline between a low-temperature evaporator and a low-temperature compressor of a low-temperature circulation loop;

[0013] The drying filter is arranged on the pipeline between the precooler and the low-temperature throttling device of the low-temperature circulation loop, and is used to dry and filter the low-temperature refrigerant medium flowing through.

[0014] In some optional embodiments, the filter drier comprises:

[0015] The first drying filter is arranged on the pipeline between the condensing part of the evaporative condenser and the low-temperature throttling member of the low-temperature circulation loop, and is used for drying and filtering the low-temperature refrigerant flowing out of the condensing part.

[0016] In some optional embodiments, the filter drier comprises:

[0017] The second drying filter is arranged in the pipeline between the first heat recovery part of the low temperature stage regenerator and the condensation part of the evaporative condenser of the low temperature stage circulation loop, and is used for drying and filtering the low temperature stage refrigerant flowing out of the first heat recovery part.

[0018] In some optional embodiments, the filter drier comprises:

[0019] The third drying filter is arranged on the pipeline between the precooler and the first reheating part of the low-temperature stage regenerator of the low-temperature stage circulation loop, and is used for drying and filtering the low-temperature stage refrigerant flowing out of the precooler.

[0020] In some optional embodiments, the high temperature stage circulation loop further comprises:

[0021] A high-temperature heat regenerator, comprising a third heat regenerator and a fourth heat regenerator capable of exchanging heat with each other, wherein the third heat regenerator is connected to a pipeline between the high-temperature condenser and the evaporative condenser of the high-temperature circulation loop, and the fourth heat regenerator is connected to a pipeline between the evaporative condenser and the high-temperature compressor of the high-temperature circulation loop;

[0022] The high-temperature liquid storage device is arranged on the pipeline between the evaporative condenser and the high-temperature compressor of the high-temperature circulation loop.

[0023] In some optional embodiments, the high temperature stage liquid reservoir comprises a first high temperature stage liquid reservoir and / or a second high temperature stage liquid reservoir; wherein,

[0024] The first high-temperature stage liquid storage device is arranged on the pipeline between the evaporative condenser and the fourth heat regenerator of the high-temperature stage circulation loop;

[0025] The second high-temperature stage liquid storage device is arranged on the pipeline between the fourth regenerative part of the high-temperature stage regenerator and the high-temperature stage compressor of the high-temperature stage circulation loop.

[0026] In some optional embodiments, the high-temperature stage compressor and the low-temperature stage compressor satisfy the following displacement relationship:

[0027] 1.5:1≤CC 高温级 :CC 低温级 ≤1:1.5,

[0028] Among them, CC 高温级 is the displacement of the high temperature compressor, CC 低温级 is the displacement of the low temperature compressor.

[0029] In some optional embodiments, the displacement CC of the high temperature stage compressor 高温级 The displacement of the low temperature compressor CC 低温级 The displacement ratio is 1:1.

[0030] In some optional embodiments, the type of high-temperature refrigerant filled in the high-temperature circulation loop includes R600 or R600a;

[0031] And / or, the type of low-temperature refrigerant filled in the low-temperature circulation loop includes R290, R1270 or a mixture thereof.

[0032] According to an embodiment of the second aspect of the present application, there is provided a refrigeration device, comprising a device body, and a cascade refrigeration system as in any one of the embodiments of the first aspect described above.

[0033] The cascade refrigeration system and refrigeration equipment provided by the embodiments of the present disclosure can achieve the following technical effects:

[0034] The cascade refrigeration system of the disclosed embodiment is provided with a precooler and a regenerator in the low-temperature stage circulation loop, and the drying filter is arranged between the precooler and the low-temperature stage throttling device, and can be selectively arranged between the precooler and the regenerator, between the regenerator and the evaporative condenser, and between the evaporative condenser and the low-temperature stage throttling device, so as to improve the actual filtering and purification effect of the drying filter by adjusting the position of the drying filter relative to other components of the low-temperature stage circulation loop.

[0035] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] One or more embodiments are exemplarily described by corresponding drawings, which do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements, and the drawings do not constitute a scale limitation, and wherein:

[0037] Figure 1 is a system schematic diagram of a cascade refrigeration system provided by an embodiment of the present disclosure;

[0038] Figure 2 is a system schematic diagram of a cascade refrigeration system provided by another embodiment of the present disclosure;

[0039] Figure 3a is a system schematic diagram of a cascade refrigeration system provided by an embodiment of the present disclosure;

[0040] Figure 3b is a system schematic diagram of a cascade refrigeration system provided by another embodiment of the present disclosure;

[0041] Figure 3c is a system schematic diagram of a cascade refrigeration system provided by an embodiment of the present disclosure;

[0042] Figure 4 is a system schematic diagram of a cascade refrigeration system provided by another embodiment of the present disclosure;

[0043] Figure 5a is a system schematic diagram of a cascade refrigeration system provided by an embodiment of the present disclosure;

[0044] Figure 5b is a system schematic diagram of a cascade refrigeration system provided by another embodiment of the present disclosure;

[0045] Figure 6 It is a schematic diagram of the structure of a refrigerator provided in one embodiment of the present disclosure.

[0046] Reference numerals:

[0047] 100, high temperature stage circulation loop; 110, high temperature stage condenser; 120, high temperature stage throttling device; 130, high temperature stage regenerator; 140, high temperature stage compressor; 151, first high temperature stage liquid storage device; 152, second high temperature stage liquid storage device;

[0048] 200, low temperature circulation loop; 210, precooler; 220, low temperature regenerator; 230, low temperature throttling device; 240, low temperature evaporator; 250, low temperature compressor; 261, first drying filter; 262, second drying filter; 263, third drying filter;

[0049] 300, evaporation condenser; 310, evaporation part; 320, condensation part;

[0050] 400. Refrigerator; 410. Equipment body; 420. Cascade refrigeration system. DETAILED DESCRIPTION

[0051] In order to be able to understand the features and technical contents of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0052] The terms "first", "second", etc. in the specification and claims of the embodiments of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the embodiments of the present disclosure described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0053] In the embodiments of the present disclosure, the terms "upper", "lower", "inside", "middle", "outside", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the embodiments of the present disclosure and their embodiments, and are not intended to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction. Moreover, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0054] In addition, the terms "disposed", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0055] The term "and / or" is a description of the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B.

[0056] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

[0057] The present application discloses a cascade refrigeration system, which can be applied to refrigeration equipment, and can enable the refrigeration equipment to form a low-temperature storage environment. Optionally, the types of refrigeration equipment include but are not limited to refrigerators, freezers, low-temperature medical boxes, etc.

[0058] In an embodiment, the cascade refrigeration system may be a cascade refrigeration cycle system with two or more stages, such as a two-stage cascade refrigeration system, a three-stage cascade refrigeration system, a four-stage cascade refrigeration system, etc. The present application does not limit the number of cascade stages of the cascade refrigeration system. In the following related embodiments, a two-stage cascade refrigeration system is used as an example.

[0059] Combination Figure 1 As shown, the embodiment of the present disclosure provides a cascade refrigeration system, which includes a high-temperature stage circulation loop 100 and a low-temperature stage circulation loop 200. The high-temperature stage circulation loop 100 and the low-temperature stage circulation loop 200 share the same evaporative condenser 300 to achieve the conduction of cold energy from the high-temperature stage circulation loop 100 to the low-temperature stage circulation loop 200.

[0060] Specifically, the high-temperature circulation loop 100 includes a high-temperature compressor 140, a high-temperature condenser 110, a high-temperature throttling device 120, and an evaporation portion 310 of an evaporative condenser 300, which are sequentially connected to the same loop, and the loop is filled with a high-temperature refrigerant. When the high-temperature circulation loop 100 is in operation, the flow direction of the high-temperature refrigerant is defined as "high-temperature compressor 140 → high-temperature condenser 110 → high-temperature throttling device 120 → evaporation portion 310 of evaporative condenser 300 → high-temperature compressor 140", and the high-temperature refrigerant absorbs heat from the outside when flowing through the evaporation portion 310 of the evaporative condenser 300, specifically, absorbs heat from the condensation portion 320 of the evaporative condenser 300, so that the temperature of the low-temperature refrigerant flowing through the condensation portion 320 is reduced.

[0061] In an embodiment, the high-temperature refrigerant forms a high-temperature and high-pressure superheated gas after being pressurized by the high-temperature compressor 140. After entering the high-temperature condenser 110, it is condensed into a supercooled liquid or a saturated liquid or a gas-liquid two-phase, and then enters the high-temperature throttling device 120 to be throttled and cooled to a low-temperature and low-pressure state. The high-temperature refrigerant then enters the evaporator 310 of the evaporative condenser 300 to release cold (absorb heat), and finally flows back into the high-temperature compressor 140 to complete a high-temperature refrigerant cycle.

[0062] The low-temperature circulation loop 200 includes a low-temperature compressor 250, a precooler 210, a condensing part 320 of an evaporative condenser 300, a low-temperature throttling device 230, and a low-temperature evaporator 240, which are sequentially connected to the same loop, and the loop is filled with a low-temperature refrigerant. When the low-temperature circulation loop 200 is in operation, the flow direction of the low-temperature refrigerant is defined as "low-temperature compressor 250 → precooler 210 → condensing part 320 of the evaporative condenser 300 → low-temperature throttling device 230 → low-temperature evaporator 240 → low-temperature compressor 250", and the low-temperature refrigerant releases heat to the outside when flowing through the condensing part 320 of the evaporative condenser 300, specifically, the heat is conducted to the evaporating part 310 of the evaporative condenser 300, so that the temperature of the low-temperature refrigerant itself is reduced.

[0063] In the present embodiment, the low-temperature refrigerant forms a high-temperature and high-pressure superheated gas after being compressed and pressurized by the low-temperature compressor 250, and enters the precooler 210 for heat dissipation and cooling; then the low-temperature refrigerant enters the condenser of the evaporative condenser 300, and becomes a supercooled liquid or a saturated liquid or a gas-liquid two-phase after heat dissipation; then, the low-temperature refrigerant enters the low-temperature throttling device 230 and is throttled to a low-temperature and low-pressure state, and then enters the low-temperature evaporator 240 for refrigeration, achieving low-temperature storage below -45°C; after the low-temperature refrigerant flows out of the low-temperature evaporator 240, it is re-inhaled into the low-temperature compressor 250, completing a low-temperature refrigerant cycle.

[0064] In the disclosed embodiment, the evaporation part 310 and the condensation part 320 of the evaporative condenser 300 can exchange heat with each other, and the heat conduction direction is limited to conduction from the condensation part 320 to the evaporation part 310. In this way, the high-temperature refrigerant medium in the high-temperature circulation loop 100 can be used to cool the low-temperature refrigerant medium in the low-temperature circulation loop 200.

[0065] In the above embodiment, the precooler 210 is used as a "condenser", which can be used to cool the low-temperature refrigerant medium output by the low-temperature compressor 250, thereby reducing the heat load of the low-temperature refrigerant medium subsequently output to the evaporative condenser 300, so that the low-temperature refrigerant medium output from the evaporative condenser 300 can reach a lower temperature.

[0066] In some optional embodiments, combined with Figure 2 As shown, the low-temperature circulation loop 200 also includes a low-temperature heat exchanger 220, which can be used to perform secondary cooling before the low-temperature refrigerant medium is input into the evaporative condenser 300, so as to further reduce the heat of the low-temperature refrigerant medium and enhance the cooling effect of the evaporative condenser 300 on the low-temperature refrigerant medium.

[0067] Here, the low-temperature regenerator 220 includes a first regenerator and a second regenerator that can exchange heat with each other. The first regenerator is connected to the pipeline between the precooler 210 and the evaporative condenser 300 of the low-temperature circulation loop 200, so that the low-temperature refrigerant flowing out of the precooler 210 first flows through the first regenerator for heat exchange, and then flows to the evaporative condenser 300; and the second regenerator is connected to the pipeline between the low-temperature evaporator 240 and the low-temperature compressor 250 of the low-temperature circulation loop 200, so that the low-temperature refrigerant flowing out of the low-temperature evaporator 240 first flows through the second regenerator for heat exchange, and then flows to the evaporative condenser 300.

[0068] In this embodiment, the low-temperature refrigerant flowing through the precooler 210 is still in a superheated steam state after being cooled, and the temperature of this part of the low-temperature refrigerant is relatively high, while the low-temperature refrigerant flowing out of the low-temperature evaporator 240 is in a liquid state or a gas-liquid state, and the temperature of this part of the low-temperature refrigerant is relatively low. In this way, when the two parts of the low-temperature refrigerant flow through the first heat recovery section and the second heat recovery section respectively, heat is transferred from the high-temperature side of the low-temperature refrigerant to the low-temperature side, thereby further reducing the temperature of the low-temperature refrigerant flowing out of the first heat recovery section.

[0069] In some optional embodiments, the low-temperature circulation loop 200 also includes a drying filter, which is arranged in the pipeline between the precooler 210 and the low-temperature throttling device 230 of the low-temperature circulation loop 200 to dry and filter the low-temperature refrigerant medium flowing through.

[0070] Here, the filter drier can specifically filter impurities in the low-temperature circulation loop 200, such as metal chips, oxides, dust, residual moisture, etc. In an embodiment, the internal structure of the filter drier is provided with a refrigerant medium passage, the two ends of which can be respectively connected to the pipeline of the low-temperature circulation loop 200, and the refrigerant medium passage is filled with an adsorbent material, which has an adsorption and purification effect on the low-temperature refrigerant flowing through, thereby intercepting impurities mixed in the refrigerant. Optionally, the adsorbent material is a porous medium material, which has a strong adsorption effect on solid and liquid impurities.

[0071] In some optional embodiments, combined with Figure 3a As shown, the drying filter includes a first drying filter 261, which is arranged in the pipeline between the condensation part 320 of the evaporative condenser 300 and the low-temperature throttling device 230 of the low-temperature circulation loop 200, and is used to dry and filter the low-temperature refrigerant medium flowing out of the condensation part 320.

[0072] In this embodiment, the low-temperature refrigerant is cooled and becomes a low-temperature liquid refrigerant after flowing through the condensation section 320 of the evaporative condenser 300. In this state, the compressor lubricating oil and the refrigerant have good miscibility, and the dry filter intercepts and adsorbs less compressor lubricating oil, thereby reducing the risk of oil blockage, and the dry filter has a better adsorption and interception effect on other impurities.

[0073] In some alternative embodiments, combined with Figure 3b As shown, the drying filter includes a second drying filter 262, which is arranged in the pipeline between the first heat recovery part of the low-temperature stage heat exchanger 220 and the condensation part 320 of the evaporative condenser 300 of the low-temperature stage circulation loop 200, and is used to dry and filter the low-temperature stage refrigerant medium flowing out from the first heat recovery part.

[0074] In this embodiment, the low-temperature refrigerant medium is cooled and cooled to a gas-liquid two-phase state after flowing through the first heat recovery part of the low-temperature regenerator 220. In this state, the miscibility of the compressor lubricating oil and the refrigerant medium is also better, the interception and adsorption amount of the compressor lubricating oil is less, and the drying filter also has a better adsorption effect on impurities.

[0075] In some alternative embodiments, combined with Figure 3c As shown, the drying filter includes a third drying filter 263, which is arranged in the pipeline between the precooler 210 and the first reheating part of the low-temperature stage regenerator 220 of the low-temperature stage circulation loop 200, and is used to dry and filter the low-temperature stage refrigerant medium flowing out of the precooler 210.

[0076] Here, the precooler 210 is arranged in a space such as a compressor compartment that is easy to exchange heat with the external environment. In this embodiment, the drying filter is located downstream of the flow path of the precooler 210. It can also be arranged in the above-mentioned compressor compartment and other spaces to enable more convenient maintenance and replacement of the drying filter.

[0077] Based on the above embodiments of various layout forms of drying filters, the cascade refrigeration system provided in the present application can be provided with one or more drying filters, and the specific arrangement position of each drying filter can refer to any one of the embodiments shown in the above embodiments.

[0078] In some alternative embodiments, combined with Figure 4 As shown, the high-temperature circulation loop 100 also includes a high-temperature heat regenerator 130, which can be used to perform secondary cooling before the high-temperature refrigerant is input into the evaporative condenser 300 to further reduce the heat of the high-temperature refrigerant and improve the evaporation heat absorption efficiency of the high-temperature refrigerant in the evaporative condenser 300.

[0079] Here, the high-temperature regenerator 130 includes a third regenerator and a fourth regenerator that can exchange heat with each other. The third regenerator is connected to the pipeline between the high-temperature condenser 110 and the evaporative condenser 300 of the high-temperature circulation loop 100, so that the high-temperature refrigerant flowing out of the high-temperature condenser 110 first flows through the third regenerator for heat exchange, and then flows to the evaporative condenser 300; and the fourth regenerator is connected to the pipeline between the evaporative condenser 300 and the high-temperature compressor 140 of the high-temperature circulation loop 100, so that the high-temperature refrigerant flowing out of the evaporative condenser 300 first flows through the fourth regenerator for heat exchange, and then flows back to the high-temperature compressor 140.

[0080] Optionally, the third heat recovery portion is disposed on the upstream and / or downstream pipeline of the high-temperature stage throttling element 120 .

[0081] In this embodiment, the high-temperature refrigerant flowing through the high-temperature condenser 110 is in a gas-liquid two-phase state after cooling, and its temperature is relatively high; and the high-temperature refrigerant flowing out of the evaporation part 310 of the evaporative condenser 300 is in a liquid state or a gas-liquid two-phase state, and its temperature is relatively low. In this way, when the two parts of the high-temperature refrigerant flow through the third heat recovery part and the fourth heat recovery part respectively, heat is transferred from the high-temperature side of the high-temperature refrigerant to the low-temperature side, thereby further reducing the temperature of the high-temperature refrigerant flowing out of the third heat recovery part, and increasing the amount of liquid refrigerant.

[0082] Generally, the compressor startup sequence of the cascade refrigeration system is to start the high-temperature compressor 140 first and then the low-temperature compressor 250. However, in actual application, after the high-temperature compressor 140 is started, since the low-temperature compressor 250 has not yet started and the condensing part 320 of the evaporative condenser 300 is in a "no heat source" state, the liquid high-temperature refrigerant throttled by the high-temperature throttling device 120 will accumulate in the evaporating part 310 of the evaporative condenser 300, and the accumulated amount may even reach 70% to 80% of the total amount of refrigerant in the high-temperature circulation loop 100; and after the low-temperature compressor 250 is started, a large amount of heat is transferred from the condensing part 320 to the evaporating part 310, resulting in rapid evaporation of the high-temperature refrigerant stored in the evaporating part 310, and a large amount of gaseous high-temperature refrigerant is generated, which makes it difficult to control the temperature and pressure of the evaporating part 310 of the evaporative condenser 300.

[0083] In view of the above situation, combined with Figure 5a and 5b As shown, in the disclosed embodiment, the high temperature circulation loop 100 further includes a high temperature liquid reservoir, which can be used to store part of the high temperature refrigerant and release the stored high temperature refrigerant to the high temperature circulation loop 100. In this way, the liquid refrigerant generated by the high temperature circulation loop 100 at the initial start-up of the compressor can be partially stored in the high temperature liquid reservoir, reducing the amount of refrigerant accumulated in the evaporative condenser 300, thereby reducing the peak pressure of the evaporation part 310 in the process of generating a large amount of gaseous refrigerant by evaporation, so as to achieve a buffering and stabilizing effect.

[0084] Optionally, the high temperature liquid reservoir is disposed on the pipeline between the evaporative condenser 300 and the high temperature compressor 140 of the high temperature circulation loop 100. Exemplarily, the high temperature liquid reservoir includes a first high temperature liquid reservoir 151 and / or a second high temperature liquid reservoir 152. The first high temperature liquid reservoir 151 is disposed on the pipeline between the evaporative condenser 300 and the fourth reheating part of the high temperature regenerator 130 of the high temperature circulation loop 100, such as Figure 5a As shown, a portion of the liquid high-temperature refrigerant medium is accumulated on the liquid outlet side of the evaporative condenser 300. The second high-temperature liquid storage device 152 is disposed on the pipeline between the fourth regenerative part of the high-temperature regenerator 130 and the high-temperature compressor 140 of the high-temperature circulation loop 100, as shown in FIG. Figure 5b As shown, part of the liquid high-temperature refrigerant is accumulated on the liquid inlet side of the high-temperature compressor 140. This arrangement can also reduce the risk of "liquid hammer".

[0085] Here, Tables 1 and 2 show the experimental test results of two prototypes A and B under the ambient temperature conditions of 25°C and 32°C, respectively. Prototype A is a model without a high-temperature liquid storage tank, and prototype B is a model with a high-temperature liquid storage tank according to the above embodiment.

[0086] Table 1

[0087]

[0088] Table 2

[0089]

[0090] Combining Tables 1 and 2, it can be seen that compared with Model A, Model B equipped with a high-temperature liquid storage tank not only has the mass of the cold medium in the high-temperature circulation loop 100 increased by about 50%, but also its peak pressure decreased by about 0.1MPa under an ambient temperature of 25°C and by about 0.22MPa under an ambient temperature of 32°C. This model withstands less peak pressure shock and the system operation is more stable.

[0091] In some other optional embodiments, the exhaust temperatures of the low-temperature compressor 250 of different types of cascade refrigeration systems are different, and the corresponding high-temperature evaporation temperature and low-temperature condensation temperature are respectively defined, so that the displacement of the corresponding high-temperature compressor 140 and low-temperature compressor 250 can be tested. As shown in Table 3 below:

[0092] Table 3

[0093]

[0094] Combined with Table 3, in order to ensure that the low-temperature storage temperature and the system temperature are controllable, the high-temperature compressor 140 and the low-temperature compressor 250 satisfy the following displacement relationship:

[0095] 1.5:1≤CC 高温级 :CC 低温级 ≤1:1.5,

[0096] Among them, CC 高温级 is the displacement of the high temperature stage compressor 140, CC 低温级 is the displacement of the low temperature stage compressor 250.

[0097] It can be seen from Table 3 that by changing the displacement CC of the high temperature stage compressor 140 高温级 With low temperature stage compressor displacement 250 cc 低温级 Setting it within the above-mentioned displacement range can not only make the low-temperature stage condensing temperature and the high-temperature stage evaporating temperature meet the system temperature setting requirements and the system condensing heat load requirements; at the same time, the low-temperature stage exhaust temperature can also be in a more reasonable temperature range, reducing the probability of safety problems of the whole machine caused by high heat load and excessively high exhaust temperature.

[0098] Furthermore, the present application also tests the exhaust temperature and the temperature inside the box corresponding to different low-temperature compressor 250 displacements when the high-temperature compressor 140 displacement is a fixed value, as shown in Table 4-1; and the exhaust temperature and the temperature inside the box corresponding to different high-temperature compressor 140 displacements when the low-temperature compressor 250 displacement is a fixed value, as shown in Table 4-2. In the two sets of test data, the displacements of the high-temperature compressor 140 and the low-temperature compressor 250 are set to 9cc respectively.

[0099] Table 4-1

[0100]

[0101] Table 4-2

[0102]

[0103] It can be seen from Table 4-1 that when the displacement of the high-temperature compressor 140 is set to 9cc, the low-temperature compressor 250 is also 9cc (i.e., the ratio is 1:1), the exhaust temperature is more reasonable, and the compressor matching is more reasonable. And, it can be seen from Table 4-2 that when the displacement of the low-temperature compressor 250 is set to 9cc, the high-temperature compressor 140 is also 9cc (i.e., the ratio is 1:1), the exhaust temperature is more reasonable, and the compressor matching is more reasonable.

[0104] Therefore, in the embodiment of the present application, the displacement ratio of the high-temperature compressor 140 CC high-temperature stage and the low-temperature compressor 250 CC low-temperature stage is preferably 1:1.

[0105] In some further embodiments, Table 5 shows the saturated vapor pressure values ​​of different refrigerants.

[0106] Table 5

[0107]

[0108] Combining Table 5 and the test results, when the pressure is lower than 0.01Mpa, the throttling effect of conventional capillary tubes and other throttling parts is low, and the system refrigerant flow and cooling capacity are very low at this time; when the pressure is higher than 1.3Mpa, the compressor vibration noise is high.

[0109] Therefore, in order to ensure the low-temperature refrigeration effect and solve the noise problem, the type of high-temperature refrigerant filled in the high-temperature circulation loop 100 includes R600 or R600a, and / or, the type of low-temperature refrigerant filled in the low-temperature circulation loop 200 includes R290, R1270 or a mixture thereof.

[0110] In some other embodiments, the present application further provides a refrigeration device, including a device body 410 and a cascade refrigeration system 420 as in any of the above embodiments. Here, the cascade refrigeration system 420 can provide cold energy to the refrigeration device to store food, medicine or other items at low temperature.

[0111] Exemplarily, the type of refrigeration equipment is a refrigerator, a freezer, a freezer, a biomedical refrigeration equipment or other refrigeration equipment. Figure 6 The type of refrigeration equipment shown is a freezer 400 product.

[0112] The above description and the accompanying drawings sufficiently illustrate the embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Unless explicitly required, individual components and functions are optional, and the order of operations may vary. Portions and features of some embodiments may be included in or replace portions and features of other embodiments. The embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A cascade refrigeration system, characterized in that: include: A high temperature stage circulation loop, comprising a high temperature stage compressor, a high temperature stage condenser, and an evaporation portion of the evaporative condenser, which are sequentially connected to the same loop; A low temperature circulation loop, comprising a low temperature compressor, a precooler, a condensing part of an evaporative condenser, a low temperature throttling device and a low temperature evaporator, which are sequentially connected to the same loop; A low-temperature heat regenerator, comprising a first heat regenerator and a second heat regenerator capable of exchanging heat with each other, wherein the first heat regenerator is connected to a pipeline between a precooler and an evaporative condenser of a low-temperature circulation loop, and the second heat regenerator is connected to a pipeline between a low-temperature evaporator and a low-temperature compressor of a low-temperature circulation loop; The drying filter is arranged on the pipeline between the precooler and the low-temperature throttling device of the low-temperature circulation loop, and is used to dry and filter the low-temperature refrigerant medium flowing through.

2. The cascade refrigeration system according to claim 1, characterized in that: The filter drier includes: The first drying filter is arranged on the pipeline between the condensing part of the evaporative condenser and the low-temperature throttling member of the low-temperature circulation loop, and is used for drying and filtering the low-temperature refrigerant flowing out of the condensing part.

3. The cascade refrigeration system according to claim 1 or 2, characterized in that: The filter drier includes: The second drying filter is arranged in the pipeline between the first heat recovery part of the low temperature stage regenerator and the condensation part of the evaporative condenser of the low temperature stage circulation loop, and is used for drying and filtering the low temperature stage refrigerant flowing out of the first heat recovery part.

4. The cascade refrigeration system according to claim 1 or 2, characterized in that: The filter drier includes: The third drying filter is arranged on the pipeline between the precooler and the first reheating part of the low-temperature stage regenerator of the low-temperature stage circulation loop, and is used for drying and filtering the low-temperature stage refrigerant flowing out of the precooler.

5. The cascade refrigeration system according to claim 1, characterized in that: The high temperature cycle loop also includes: A high-temperature heat regenerator, comprising a third heat regenerator and a fourth heat regenerator capable of exchanging heat with each other, wherein the third heat regenerator is connected to a pipeline between the high-temperature condenser and the evaporative condenser of the high-temperature circulation loop, and the fourth heat regenerator is connected to a pipeline between the evaporative condenser and the high-temperature compressor of the high-temperature circulation loop; The high-temperature liquid storage device is arranged on the pipeline between the evaporative condenser and the high-temperature compressor of the high-temperature circulation loop.

6. The cascade refrigeration system according to claim 5, characterized in that: The high temperature stage liquid reservoir comprises a first high temperature stage liquid reservoir and / or a second high temperature stage liquid reservoir; wherein, The first high-temperature stage liquid storage device is arranged on the pipeline between the evaporative condenser and the fourth heat regenerator of the high-temperature stage circulation loop; The second high-temperature stage liquid storage device is arranged on the pipeline between the fourth regenerative part of the high-temperature stage regenerator and the high-temperature stage compressor of the high-temperature stage circulation loop.

7. The cascade refrigeration system according to claim 1, characterized in that: The high-temperature compressor and the low-temperature compressor satisfy the following displacement relationship: 1.5:1≤CC 高温级 :CC 低温级 ≤1:1.5, Among them, CC 高温级 is the displacement of the high temperature compressor, CC 低温级 is the displacement of the low temperature compressor.

8. The cascade refrigeration system according to claim 1 or 7, characterized in that: Displacement CC of high temperature compressor 高温级 The displacement of the low temperature compressor CC 低温级 The displacement ratio is 1:

1.

9. The cascade refrigeration system according to claim 8, characterized in that: The types of high-temperature refrigerants filled in the high-temperature circulation loop include R600 or R600a; And / or, the type of low-temperature refrigerant filled in the low-temperature circulation loop includes R290, R1270 or a mixture thereof.

10. A refrigeration device, characterized in that: It comprises a device body and a cascade refrigeration system as claimed in any one of claims 1 to 9.

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