CN113432327B

CN113432327B - Cascade compression refrigeration system and refrigeration equipment with same

Info

Publication number: CN113432327B
Application number: CN202010209790.XA
Authority: CN
Inventors: 赵向辉; 陶瑞涛; 刘煜森; 孙永升; 冯茹丹
Original assignee: Qingdao Haier Smart Technology R&D Co Ltd; Haier Smart Home Co Ltd
Current assignee: Qingdao Haier Smart Technology R&D Co Ltd
Priority date: 2020-03-23
Filing date: 2020-03-23
Publication date: 2024-08-16
Anticipated expiration: 2040-03-23
Also published as: CN113432327A

Abstract

The present invention provides a cascade compression refrigeration system and a refrigeration device having the same. The cascade compression refrigeration system comprises: a high-temperature refrigeration cycle loop for circulating a first refrigerant; a low-temperature refrigeration cycle loop for circulating a second refrigerant; a heat exchange component, which comprises: a heat release portion, which is arranged in the high-temperature refrigeration cycle loop and located between the high-temperature compressor discharge port and the evaporation portion; a heat absorption portion, which is arranged in the low-temperature refrigeration cycle loop and located between the low-temperature evaporation pipe and the low-temperature compressor suction port; the heat absorption portion is used to cause the second refrigerant flowing through it to absorb the heat of the first refrigerant flowing through the heat release portion and heat up, thereby being able to increase the suction temperature of the low-temperature compressor, and is suitable for application scenarios such as household refrigerators and freezers.

Description

Cascade compression refrigeration system and refrigeration equipment with same

Technical Field

The invention relates to the field of refrigeration, in particular to an overlapping type compression refrigeration system and refrigeration equipment with the same.

Background

Cascade compression refrigeration systems are typically composed of two separate refrigeration cycle circuits, referred to as a high temperature stage refrigeration cycle (high temperature section) and a low temperature stage refrigeration cycle (low temperature section), respectively. The high temperature portion uses a first refrigerant having a relatively high normal boiling point, and the low temperature portion uses a second refrigerant having a relatively low normal boiling point. The condensing evaporator condenses the second refrigerant vapor discharged from the compressor of the low temperature part by utilizing the cold energy produced by the first refrigerant of the high temperature part, and is not only the evaporator of the high temperature part but also the condenser of the low temperature part.

In the prior art, in the low-temperature-stage refrigeration cycle, the temperature of the second refrigerant flowing from the muffler to the suction inlet of the low-temperature-stage compressor is low, so that the suction temperature of the compressor in the low-temperature part is low, and condensation or frosting is caused around the muffler of the low-temperature-stage compressor and the suction inlet of the low-temperature-stage compressor, thereby leading to the loss of refrigeration capacity. For small-sized domestic refrigeration equipment, the refrigeration efficiency is obviously reduced due to the loss of tens of watts or even a few watts of cold energy.

Therefore, how to increase the compressor suction temperature of the low temperature portion is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

It is an object of the present invention to provide an cascade compression refrigeration system and a refrigeration apparatus having the same that at least partially solves the above-mentioned problems.

A further object of the present invention is to increase the suction temperature of a low temperature stage compressor in a low temperature stage refrigeration cycle in a cascade compression refrigeration system.

It is a further object of the present invention to increase the refrigeration efficiency of a storage compartment in a refrigeration appliance having an cascade compression refrigeration system.

A further object of the present invention is to improve the refrigeration efficiency in a high temperature stage refrigeration cycle in an cascade compression refrigeration system.

A further object of the present invention is to improve the efficiency of energy utilization in a low temperature stage refrigeration cycle in an cascade compression refrigeration system.

The invention provides an cascade compression refrigeration system and refrigeration equipment with the cascade compression refrigeration system, comprising: a high-temperature-stage refrigeration cycle circuit for circulating a first refrigerant, and having a high-temperature-stage compressor and an evaporation unit disposed therein; a low-temperature-stage refrigeration cycle for circulating a second refrigerant, and having a low-temperature-stage compressor, a condensing part, and a low-temperature-stage evaporation pipe disposed therein; the evaporation part is used for promoting the first refrigerant flowing through the evaporation part to absorb the heat of the second refrigerant flowing through the condensation part; and a heat exchange assembly, comprising: the heat release part is arranged in the high-temperature-stage refrigeration cycle loop and is positioned between the discharge port of the high-temperature-stage compressor and the evaporation part; the heat absorption part is arranged in the low-temperature-stage refrigeration cycle loop and is positioned between the low-temperature-stage evaporation pipe and the suction inlet of the low-temperature-stage compressor; the heat absorbing portion is for causing the second refrigerant flowing therethrough to absorb heat of the first refrigerant flowing through the heat releasing portion.

Optionally, the high temperature stage refrigeration cycle further comprises: the high-temperature-stage condenser is arranged between the discharge port of the high-temperature-stage compressor and the evaporation part, and the heat release part is positioned between the high-temperature-stage condenser and the evaporation part.

Optionally, the high temperature stage refrigeration cycle further comprises: a plurality of cold supply branches which are mutually connected in parallel, wherein each cold supply branch is internally provided with a branch throttling device; the plurality of cold supply branches includes: a first cooling branch circuit, in which a first cooling evaporation tube is arranged, the first cooling evaporation tube being used for promoting the first refrigerant flowing through the first cooling branch circuit to absorb heat; the first cold supply evaporation pipe and the low-temperature level evaporation pipe are used for supplying cold for the same storage compartment.

Optionally, the first cold supply evaporating pipe and the low-temperature level evaporating pipe are arranged on the same fin group in a penetrating way.

Optionally, a check valve is further disposed in the first cooling branch, and the check valve is disposed downstream of the first cooling evaporation tube, and is configured to allow only the first refrigerant from the first cooling evaporation tube to flow out in a single direction.

Optionally, the high temperature stage refrigeration cycle further comprises: the second cooling evaporator is arranged between the heat release part and the high-temperature-stage compressor suction inlet and is used for promoting the first refrigerant from the plurality of cooling branches to pass to the high-temperature-stage compressor suction inlet.

Optionally, the evaporation part is arranged between the heat release part and the second cooling evaporator; and a plurality of cooling branches are arranged between the heat release part and the evaporation part.

Optionally, the plurality of cooling branches are disposed between the heat release part and the second cooling evaporator; the plurality of cooling branches further includes: the evaporation part is arranged in the second cooling branch.

Optionally, the high temperature stage refrigeration cycle further comprises: the dew-proof pipe is arranged between the high-temperature-stage condenser and the cooling branch and is used for promoting the first refrigerant flowing through the dew-proof pipe to release heat; the heat release part is arranged between the high-temperature-stage condenser and the anti-dew pipe; the liquid storage bag with the height Wen Jidi is arranged between the heat release part and the dew prevention pipe.

Optionally, the low-temperature-stage refrigeration cycle further comprises: the low-temperature-stage throttling device is arranged between the condensing part and the low-temperature-stage evaporation pipe; the heat absorption and return air pipe section is arranged between the low-temperature-stage evaporation pipe and the heat absorption part; at least part of the heat absorption air return pipe section and the low-temperature-stage throttling device are mutually abutted or sleeved, so that the second refrigerant flowing through the heat absorption air return pipe section absorbs heat of the second refrigerant flowing through the low-temperature-stage throttling device.

According to another aspect of the present invention, there is also provided a refrigeration apparatus including: a case; the cascade compression refrigeration system of any of the above claims disposed within the housing.

The invention relates to an cascade compression refrigeration system and refrigeration equipment with the same, wherein the cascade compression refrigeration system comprises a high-temperature-stage refrigeration cycle loop, a low-temperature-stage refrigeration cycle loop and a heat exchange assembly. The heat exchange assembly is provided with a heat release part which is arranged in the high-temperature-stage refrigeration cycle loop and is positioned between the discharge port of the high-temperature-stage compressor and the evaporation part, and a heat absorption part which is arranged in the low-temperature-stage refrigeration cycle loop and is positioned between the low-temperature-stage evaporation pipe and the suction port of the low-temperature-stage compressor. The heat absorption part is used for promoting the second refrigerant flowing through the heat absorption part to absorb the heat of the first refrigerant flowing through the heat release part, so that the temperature of the second refrigerant in the low-temperature-stage refrigeration cycle loop is raised before the second refrigerant flows into the suction inlet of the compressor, the suction temperature of the low-temperature-stage compressor can be increased, the cold energy loss caused by the excessively low suction temperature can be reduced or avoided, the refrigeration efficiency is improved, the condensation or frosting is avoided near the suction inlet of the low-temperature-stage compressor, and the performance of the cascade compression refrigeration system is improved.

Further, according to the cascade compression refrigeration system and the refrigeration equipment with the cascade compression refrigeration system, the first cold supply evaporation pipe and the low-temperature level evaporation pipe in the high-temperature level refrigeration cycle loop are arranged on the same fin group in a penetrating mode, and the first cold supply evaporation pipe and the low-temperature level evaporation pipe are used for supplying cold for the same storage compartment, so that the refrigeration efficiency of the storage compartment can be improved, and the storage compartment can be cooled rapidly.

Further, the cascade compression refrigeration system and the refrigeration equipment with the cascade compression refrigeration system provided by the invention have the advantages that the first cold supply evaporation pipe is arranged between the heat release part and the evaporation part, the first cold supply evaporation pipe promotes the first refrigerant flowing through the first cold supply evaporation pipe to evaporate and absorb heat and supply cold for the storage compartment, and the cold quantity generated in the high-temperature-stage refrigeration cycle loop is fully utilized. The heat release part is arranged between the high-temperature-stage condenser and the evaporation part, and the first refrigerant flowing through the heat release part transfers heat to the second refrigerant flowing through the heat absorption part, so that the supercooling degree of the first refrigerant can be increased, and the refrigerating efficiency of the high-temperature-stage refrigerating cycle circuit is improved.

Further, the cascade compression refrigeration system and the refrigeration equipment with the cascade compression refrigeration system are also provided with the low-temperature-stage throttling device and the heat absorption air return pipe section in the low-temperature-stage refrigeration cycle loop, wherein the low-temperature-stage throttling device is arranged between the condensation part and the low-temperature-stage evaporation pipe, the heat absorption air return pipe section is arranged between the low-temperature-stage evaporation pipe and the heat absorption part, and at least part of the heat absorption air return pipe section is arranged in a leaning way with the low-temperature-stage throttling device, so that the second refrigerant flowing through the heat absorption air return pipe section absorbs the heat of the second refrigerant flowing through the low-temperature-stage throttling device, the energy utilization efficiency in the low-temperature-stage refrigeration cycle loop is improved, and the energy utilization efficiency of the whole refrigeration equipment is further improved.

The above, as well as additional objectives, advantages, and features of the present invention will become apparent to those skilled in the art from the following detailed description of a specific embodiment of the present invention when read in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter by way of example and not by way of limitation with reference to the accompanying drawings. The same reference numbers will be used throughout the drawings to refer to the same or like parts or portions. It will be appreciated by those skilled in the art that the drawings are not necessarily drawn to scale. In the accompanying drawings:

FIG. 1 is a schematic diagram of a refrigeration appliance having an cascade compression refrigeration system according to one embodiment of the invention;

FIG. 2 is a schematic diagram of an cascade compression refrigeration system according to one embodiment of the invention;

Fig. 3 is a schematic diagram of an cascade compression refrigeration system in accordance with another embodiment of the invention.

Detailed Description

Fig. 1 is a schematic diagram of a refrigeration appliance 10 having an cascade compression refrigeration system in accordance with an embodiment of the invention.

The refrigeration appliance 10 may be a small, household refrigeration appliance for storing food, pharmaceutical, or other items, and may be, for example, a refrigerator, or an ice bin.

Although cascade compression refrigeration systems have been involved in large-scale refrigeration equipment, the prior art cascade compression refrigeration systems have not been applicable to small-scale refrigeration equipment for home use due to excessive noise and excessive energy consumption in operation.

The cascade compression refrigeration system of the present embodiment is particularly suitable for use with a small household refrigeration appliance 10, such as a refrigerator.

The refrigerating apparatus 10 in the present embodiment is exemplified by a refrigerator. The refrigeration appliance 10 having an cascade compression refrigeration system may be a refrigerator.

The refrigeration appliance 10 may generally include: the box 110 and the cascade compression refrigeration system arranged in the box 110. Wherein, a storage compartment 111 for storing articles is also formed in the case 110. In this embodiment, the storage compartments 111 may be plural, and may include, for example, a refrigerating compartment, a freezing compartment (which is a normal freezing compartment), a temperature changing compartment, and/or a cryogenic compartment. In other alternative embodiments, the storage compartment 111 may be one, for example, a cryogenic compartment or a variable temperature compartment. The case 110 may further have a plurality of evaporator installation cavities formed therein for installing the evaporators, and the evaporator installation cavities may be provided at the back, side or bottom of the storage compartment 111.

Fig. 2 is a schematic diagram of an cascade compression refrigeration system in accordance with an embodiment of the invention.

The cascade compression refrigeration system can be a two-stage cascade circulation system, a three-stage cascade circulation system or a four-stage cascade circulation system, and the cascade stages are not particularly limited. The present embodiment is exemplified only with a cascade compression refrigeration system having a two-stage cascade circulation system, on the basis of which those skilled in the art should fully develop the ability.

The cascade compression refrigeration system may include: the high-temperature-stage refrigeration cycle, the low-temperature-stage refrigeration cycle, and the heat exchange assembly 240 may further include: a heat dissipation fan 280 and a blower fan 290. The high-temperature-stage refrigeration cycle loop forms a high-temperature-stage refrigeration cycle system, and the low-temperature-stage refrigeration cycle loop forms a low-temperature-stage refrigeration cycle system.

A high temperature stage refrigeration cycle circuit for circulating a first refrigerant, and provided therein with a high temperature stage compressor 211 and an evaporation unit 231.

A low temperature stage refrigeration cycle for circulating the second refrigerant, and provided therein are a low temperature stage compressor 251, a condensing part 232, and a low temperature stage evaporation pipe 256. Wherein the low-temperature-stage evaporation tube 256 is used for promoting the second refrigerant flowing through the low-temperature-stage evaporation tube to absorb heat in the storage compartment 111, so that the storage compartment 111 is cooled.

The evaporation portion 231 serves to cause the first refrigerant flowing therethrough to absorb heat of the second refrigerant flowing through the condensation portion 232. The condensing portion 232 may be located between the discharge of the low temperature stage compressor 251 and the low temperature stage evaporator 256. The evaporation portion 231 and the condensation portion 232 may be thermally connected such that the first refrigerant flowing through the evaporation portion 231 may absorb heat released from the second refrigerant flowing through the condensation portion 232. For example, the evaporation part 231 and the condensation part 232 may be integrally formed to form the condensation evaporator 230, and the condensation evaporator 230 may be a double pipe heat exchanger.

The high temperature stage refrigeration cycle circuit further includes: the high-temperature-stage condenser 212 is provided between the discharge port of the high-temperature-stage compressor 211 and the evaporation unit 231.

That is, the high temperature stage refrigeration cycle may include: a high-temperature-stage compressor 211, a high-temperature-stage condenser 212, and an evaporation unit 231.

The refrigerant, also called refrigerant, generally performs energy conversion by phase change, is a working substance that circulates in a refrigeration system of the refrigeration apparatus 10, and its working principle is: the refrigerant absorbs heat of the substance to be cooled in the evaporator and evaporates, and the absorbed heat is transferred to the surrounding air or water in the condenser and cooled to liquid, and the refrigerant circulates back and forth, whereby the refrigeration effect is achieved by means of a change of state. Refrigerants are classified into three general categories, namely, the size of condensing pressure at normal temperature and the evaporating temperature at atmospheric pressure: high temperature refrigerant, medium temperature refrigerant, and low temperature refrigerant. The "high temperature" and "low temperature" in the "high temperature stage refrigeration cycle loop" and the "low temperature stage refrigeration cycle loop" are relatively speaking, and the evaporation temperature of the first refrigerant flowing through the high temperature stage refrigeration cycle loop is higher than the evaporation temperature of the second refrigerant flowing through the low temperature stage refrigeration cycle loop.

The refrigerant can be further classified into three types according to the composition of the refrigerant: pure working medium refrigerants, azeotropic refrigerants and non-azeotropic refrigerants. Pure working medium refrigerant, also called single refrigerant, refers to a refrigerant formed from a single component material. The azeotropic refrigerant is formed by mixing two or more than two mutually soluble single-component substances according to a certain mass ratio or volume ratio at normal temperature, and has the same properties as single refrigerant, constant evaporation temperature under constant pressure and the same component liquids of gas phase and liquid phase. The non-azeotropic refrigerant is a solution formed by mixing two or more than two single refrigerants which do not form an azeotropic solution mutually, when the solution is heated, the evaporation proportion of the components which are easy to volatilize is large, the evaporation proportion of the components which are difficult to volatilize is small under a certain evaporation pressure, the compositions of gas and liquid phases are different, the temperature of the refrigerant is changed in the evaporation process, and the refrigerant also has similar characteristics in the condensation process.

The first refrigerant of the present embodiment may be a medium temperature refrigerant, and the second refrigerant may be a low temperature refrigerant.

The absolute pressure range of the high pressure side of the low temperature level refrigeration cycle in the steady operation state is configured to be 2-11 bar, and the absolute pressure range of the low pressure side of the low temperature level refrigeration cycle in the steady operation state is configured to be 0.2-1.1 bar.

Wherein, the high pressure side in the low temperature level refrigeration cycle refers to: in the flow direction of the second refrigerant, a portion between the discharge port of the low-temperature-stage compressor 251 and the upstream of the suction port of the low-temperature-stage throttle device 255 in the low-temperature-stage refrigeration cycle. The low pressure side in the low temperature stage refrigeration cycle refers to: in the flow direction of the second refrigerant, a portion between the downstream of the discharge port of the low-temperature-stage throttle device 255 and the suction port of the low-temperature-stage compressor 251 in the low-temperature-stage refrigeration cycle. In general, the absolute pressure of the high pressure side of the low temperature stage refrigeration cycle may be detected at a preset position near the downstream of the discharge port of the low temperature stage compressor 251, and the absolute pressure of the low pressure side of the low temperature stage refrigeration cycle may be detected at a preset position near the upstream of the suction port of the low temperature stage compressor 251. In some alternative embodiments, if the low-pressure stage compressor 251 has a process port for directly communicating with a low-pressure chamber inside the low-pressure stage compressor 251, the above-described low-pressure side absolute pressure can be detected at the process port.

The low-temperature-level refrigeration cycle loop can enter a stable running state after being started for a certain time. In the embodiment, whether the low-temperature-stage refrigeration cycle is in a stable operation state is judged according to the absolute pressure of the low-pressure side of the low-temperature-stage refrigeration cycle. After the low-temperature-level refrigeration cycle loop is started, the absolute pressure of the low-pressure side of the low-temperature-level refrigeration cycle loop can be continuously collected. If the ratio between the highest value of the absolute pressure magnitude of the low-pressure side of the low-temperature-stage refrigeration cycle and the average value of the absolute pressure magnitude of the low-pressure side of the low-temperature-stage refrigeration cycle is smaller than the first preset ratio within the first set time, and the ratio between the lowest value of the absolute pressure magnitude of the low-pressure side of the low-temperature-stage refrigeration cycle and the average value of the absolute pressure magnitude of the low-pressure side of the low-temperature-stage refrigeration cycle is larger than the second preset ratio, the low-temperature-stage refrigeration cycle within the first set time is indicated to be in a stable running state. The average value of the low-pressure side absolute pressure of the low-temperature-stage refrigeration cycle is an arithmetic average value of the highest value of the low-pressure side absolute pressure of the low-temperature-stage refrigeration cycle and the lowest value of the low-pressure side absolute pressure of the low-temperature-stage refrigeration cycle within a first set time. The first set time may be any time in the range of 0.25 to 1h, for example, may be 0.25h,0.5h, or 1h, and preferably, may be 0.25h or 0.5h. The first preset ratio may be any value in the range of 1 to 1.2, for example, may be 1,1.1, or 1.2, preferably may be 1.1, and the second preset ratio may be any value in the range of 0.85 to 0.95, for example, may be 0.85,0.9 or 0.95, preferably may be 0.9. In this embodiment, the absolute pressure of the low pressure side of the low temperature stage refrigeration cycle may be collected after a test pack (GB/T8059) is placed in the storage compartment 111 of the refrigeration apparatus 10, so as to monitor the steady operation state of the low temperature stage refrigeration cycle.

Because the exhaust pressure of the low-temperature-stage compressor 251 is set corresponding to the absolute pressure of the high-pressure side of the low-temperature-stage refrigeration cycle, the suction pressure of the low-temperature-stage compressor 251 is set corresponding to the absolute pressure of the low-pressure side of the low-temperature-stage refrigeration cycle, and when the low-temperature-stage refrigeration cycle is operated, the low-temperature-stage compressor 251 has lower suction pressure and lower exhaust pressure, so that noise generated during operation can be effectively reduced, energy consumption during operation can be reduced, and the low-temperature-stage compressor 251 can be suitable for the household small-sized refrigeration equipment 10.

The absolute pressure range of the high pressure side of the low temperature stage refrigeration cycle in the steady operation state may be configured to be 2 to 9bar, or 2 to 10bar. The absolute pressure on the high pressure side of the low temperature stage refrigeration cycle in steady operation may be any value within 2 to 11bar, for example, 2bar,3bar,4bar,5bar,6bar,7bar,8bar,9bar,10bar or 11bar.

The low-side minimum absolute pressure range of the low-temperature-stage refrigeration cycle in a steady operation state may be configured to be 0.2 to 0.8bar, or 0.2 to 0.6bar, or 0.2 to 0.5bar, or 0.2 to 0.4bar.

In some alternative embodiments, the lower limit value of the low pressure side absolute pressure of the low temperature stage refrigeration cycle in the steady operation state may be configured to have a value ranging from 0.2 to 0.8bar, alternatively from 0.2 to 0.6bar, alternatively from 0.2 to 0.5bar, alternatively from 0.2 to 0.4bar.

The low temperature stage refrigeration cycle may be preset with a plurality of refrigeration temperatures, for example, the refrigeration temperatures may be, but are not limited to, 5 ℃, -5 ℃, -18 ℃, -40 ℃, -60 ℃ or-80 ℃. The low-temperature-level refrigeration cycle can reach respective stable running states when running according to different refrigeration temperatures. The absolute pressure of the low pressure side of the low temperature stage refrigeration cycle in the steady operation state may be different depending on the refrigeration temperature. The absolute pressure of the low-pressure side of the low-temperature-stage refrigeration cycle in a stable operation state reaches a lower limit value in a set time period before the low-temperature-stage refrigeration cycle is stopped. The lower limit value of the absolute pressure of the low pressure side of the low temperature stage refrigeration cycle in the steady operation state may be different depending on the refrigeration temperature, but may be in the range of 0.2 to 0.8bar, or 0.2 to 0.6bar, or 0.2 to 0.5bar, or 0.2 to 0.4 bar.

The low-side minimum absolute pressure of the low-temperature-stage refrigeration cycle in a steady operation state may be any value in the range of 0.2 to 0.8bar, for example, may be 0.2bar,0.3bar,0.4bar,0.5bar,0.6bar,0.7bar, or 0.8bar.

The evaporation temperature range of the second refrigerant at the low pressure side of the low temperature stage refrigeration cycle in the steady operation state may be configured to be-111 to-35 ℃. The evaporation temperature of the second refrigerant at the low pressure side in the low temperature stage refrigeration cycle may refer to the evaporation temperature of the second refrigerant in the low temperature stage evaporation tube 256. The evaporating temperature of the second refrigerant in the low-temperature-level evaporating pipe 256 can reach below-60 ℃ or even below-80 ℃, can be used for creating low temperature of about-60 ℃ or even-80 ℃ for the storage compartment 111 in the household small-sized refrigeration equipment 10, and improves the fresh-keeping capability of the household small-sized refrigeration equipment 10.

In the present embodiment, the evaporation temperature range of the second refrigerant at the low pressure side of the low temperature stage refrigeration cycle in the steady operation state may be configured to be-80 to-35 ℃, or-75 to-40 ℃.

The second refrigerant can be a pure working medium refrigerant or an azeotropic refrigerant, and the standard boiling point range of the second refrigerant can be configured to be-60 to-30 ℃, or-55 to-35 ℃, or-50 to-35 ℃. For example, the second refrigerant may be an R22 refrigerant (normal boiling point may be-40.8 ℃), or may be an R290 refrigerant (normal boiling point may be-42.2 ℃), or may be an R404A refrigerant (normal boiling point may be-46.1 ℃), or may be an R1270 refrigerant (normal boiling point may be-47.7 ℃), or may be an R410A refrigerant (normal boiling point may be-51.4 ℃), or may be an R32 refrigerant (normal boiling point may be-51.7 ℃).

The low temperature stage compressor 251 may be an R600a compressor. When the existing R600a compressor is applied to a low-temperature-stage refrigeration cycle, the low-temperature lubricating oil can be replaced in the R600a compressor, so that the process is simple and the cost is low. Because the R600a compressor has lower running noise and higher energy efficiency, the noise of the low-temperature-level refrigeration cycle can be reduced by combining the R600a compressor with the R290 refrigerant, and the energy-saving effect is improved.

The type of the low temperature stage compressor 251 is not limited thereto, and any type of compressor having the above-described operation performance may be used as the low temperature stage compressor 251.

For example, the high side absolute pressure of the low temperature stage refrigeration cycle in a steady state operation may be 3.022bar and the low side absolute pressure may be 0.368bar. The second refrigerant may be an R290 refrigerant. The condensation temperature of the second refrigerant at the high pressure side in the low-temperature-stage refrigeration cycle may be-12.1 ℃ and the evaporation temperature at the low pressure side may be-62.8 ℃, so that a low-temperature environment of about-55 ℃ may be created for the storage compartment 111 when the low-temperature-stage refrigeration cycle operates. The absolute pressure of the low-pressure side of the low-temperature-level refrigeration cycle in a stable operation state can be 0.287bar, and the evaporation temperature of the second refrigerant at the low-pressure side in the low-temperature-level refrigeration cycle can be 67.2 ℃ below zero, so that a low-temperature environment of about 60 ℃ can be created for the storage compartment 111 when the low-temperature-level refrigeration cycle operates.

In some alternative embodiments, the high side absolute pressure of the low temperature stage refrigeration cycle in steady state operation may be 3.507bar and the low side absolute pressure may be 0.287bar. The second refrigerant may be an R1270 refrigerant.

The condensation temperature of the second refrigerant at the high pressure side in the low-temperature-stage refrigeration cycle may be-16 ℃, and the evaporation temperature at the low pressure side may be-72 ℃, so that a low-temperature environment of about-65 ℃ may be created for the storage compartment 111 when the low-temperature-stage refrigeration cycle operates.

In other alternative embodiments, the evaporation temperature range of the second refrigerant on the low pressure side of the low temperature stage refrigeration cycle in the steady operation state may be further configured to be-111 to-50 ℃.

The second refrigerant may be a non-azeotropic refrigerant, wherein the second refrigerant may comprise the first component. The normal boiling point range of the first component may be configured to be-60 to 0 ℃, or-50 to 0 ℃, or-45 to 0 ℃, or-15 to 0 ℃. The first component may be configured to be in a range of 20% to 80% by mass of the second refrigerant.

For example, the second refrigerant may include an R600a refrigerant and an R170 refrigerant, where the first component may be an R600a refrigerant, and the mass fraction of the R600a refrigerant in the second refrigerant may be in a range of 30% to 80%, or 40% to 60%. Or the second refrigerant may include an R600 refrigerant and an R170 refrigerant, wherein the first component may be the R600 refrigerant, and the mass fraction of the R600 refrigerant in the second refrigerant may be in a range of 40% to 80%. Or the second refrigerant may include an R600a refrigerant and an R1150 refrigerant, wherein the first component may be an R600a refrigerant, and the mass fraction of the R600a refrigerant in the second refrigerant may be in the range of 40% to 80%. Or the second refrigerant may include an R600 refrigerant and an R1150 refrigerant, wherein the first component may be an R600 refrigerant, and the mass fraction of the R600 refrigerant in the second refrigerant may be in the range of 50% to 80%. Or the second refrigerant may include an R290 refrigerant and an R170 refrigerant, wherein the first component may be an R290 refrigerant, and the mass fraction of the R290 refrigerant in the second refrigerant may be in the range of 50% to 70%. Or the second refrigerant may include an R290 refrigerant and an R1150 refrigerant, wherein the first component may be an R290 refrigerant, and the mass fraction of the R290 refrigerant in the second refrigerant may be in the range of 70% to 80%. Or the second refrigerant may comprise R1270 refrigerant and R170 refrigerant, wherein the first component may be R1270 refrigerant, and the mass fraction of R1270 refrigerant in the second refrigerant may be in the range of 60% to 80%. Or the second refrigerant may comprise R1270 refrigerant and R1150 refrigerant, wherein the first component may be R1270 refrigerant, and the mass fraction of R1270 refrigerant in the second refrigerant may be in the range of 70% to 80%.

The ODP (Ozone Depletion Potential for representing ozone depletion potential) value of the second refrigerant may be configured to be 0, and the GWP ₁₀₀ (calculated based on 100 years, denoted GWP ₁₀₀, where GWP is an abbreviation of Global Warming Potential for representing global warming potential) value of the second refrigerant may be configured to be 200 or less.

The evaporation temperature range of the first refrigerant at the low pressure side of the high-temperature-stage refrigeration cycle in a stable operation state may be configured to be-40 to 0 ℃, or-35 to-10 ℃, or-30 to-15 ℃. The condensation temperature of the second refrigerant at the high pressure side in the low temperature stage refrigeration cycle is higher than the evaporation temperature of the first refrigerant flowing through the low pressure side in the high temperature stage refrigeration cycle, for example, the condensation temperature of the second refrigerant at the high pressure side in the low temperature stage refrigeration cycle may range from-25 ℃ to-5 ℃.

The first refrigerant in the high-temperature-stage refrigeration cycle absorbs heat of the second refrigerant in the low-temperature-stage refrigeration cycle that flows through the condensing part 232 while flowing through the evaporating part, so that the second refrigerant in the condensing part 232 is cooled down and condensed into a liquid state. That is, the high-temperature-stage refrigeration cycle circuit may provide a pre-cooling function to the low-temperature-stage refrigeration cycle circuit using the first refrigerant, so that the second refrigerant in the low-temperature-stage refrigeration cycle circuit can be converted from a gaseous state to a liquid state. The second refrigerant absorbs heat and evaporates in the low-temperature-stage evaporation tube 256, and absorbs a large amount of heat, thereby realizing an effective refrigeration function at a lower temperature.

For example, the first refrigerant may be an R600a refrigerant and the high temperature stage compressor 211 may be an R600a compressor. In the high-temperature-stage refrigeration cycle, the condensation temperature of the first refrigerant on the high-pressure side is higher than the ambient temperature, and the first refrigerant releases heat on the high-pressure side. The first refrigerant flowing through the evaporation portion (low pressure side) of the high temperature stage refrigeration cycle may absorb heat of the second refrigerant flowing through the condensation portion 232 (high pressure side) of the low temperature stage refrigeration cycle, so that the second refrigerant flowing through the condensation portion 232 is condensed.

In the low-temperature-stage refrigeration cycle, when the ambient temperature is configured as a normal indoor temperature, the normal indoor temperature may be any value in the range of 7 to 40 ℃, and when the suction temperature range of the low-temperature-stage compressor 251 is 10 to 38 ℃, the suction superheat degree of the low-temperature-stage compressor 251 is 80 to 95K (K is a thermodynamic temperature unit), the discharge temperature of the low-temperature-stage compressor 251 may be configured to be 110 ℃ or less, and the case temperature of the low-temperature-stage compressor 251 may be configured to be 110 ℃ or less. In other alternative embodiments, where the suction temperature of the low temperature stage compressor 251 is in the range of 15 to 35 ℃, the suction superheat of the low temperature stage compressor 251 is in the range of 80 to 85K (K is the thermodynamic temperature unit), the discharge temperature of the low temperature stage compressor 251 may be configured to be 100 ℃ or less, and the shell temperature of the low temperature stage compressor 251 may be configured to be 100 ℃ or less.

The cylinder volume of the low temperature stage compressor 251 may be configured to be 20ml or less, for example, the cylinder volume of the low temperature stage compressor 251 may be configured to be 4 to 20ml, or 5 to 15ml, or 8.5 to 13.5ml. Wherein the low-temperature stage compressor 251 may be a piston type.

The low-temperature-stage refrigeration cycle is not provided with an injection cooling circuit.

A heat exchange assembly 240 including a heat releasing portion 241 and a heat absorbing portion 242. The heat radiation portion 241 is provided in the high-temperature-stage refrigeration cycle and is located between the discharge port of the high-temperature-stage compressor 211 and the evaporation portion 231. For example, the heat release portion 241 may be disposed between the high temperature stage condenser 212 and the evaporation portion 231. The heat absorbing unit 242 is provided in the low-temperature-stage refrigeration cycle and is located between the low-temperature-stage evaporation pipe 256 and the suction port of the low-temperature-stage compressor 251. The heat emitting portion 241 and the heat absorbing portion 242 may be sleeved with each other or disposed against each other such that heat exchange may occur between the first refrigerant flowing through the heat emitting portion 241 and the second refrigerant flowing through the heat absorbing portion 242. The heat absorbing portion 242 serves to promote the second refrigerant flowing therethrough to absorb heat of the first refrigerant flowing through the heat releasing portion 241.

The heat exchange assembly 240 of the present embodiment may be a double pipe heat exchanger. The double-pipe heat exchanger is formed by mutually sleeving and connecting two standard pipes with different sizes, wherein the outer channel is called shell side, and the inner channel is called tube side. The two different media can flow reversely (or in the same direction) in the shell side and the tube side to achieve the heat exchange effect. The heat absorbing portion 242 may be a shell side, and the heat releasing portion 241 may be a tube side. In alternative embodiments, the heat exchange assembly 240 may be two copper tubes that abut each other, with one copper tube being the heat sink 242 and the other copper tube being the heat sink 241. The two copper pipes are mutually and closely arranged. And the contact part between the two copper pipes can be fixed by soldering so as to strengthen heat transfer. Aluminum foil can be wrapped on the outer parts of the two copper pipes.

In some alternative embodiments, the first refrigerant is turned into a high-temperature and high-pressure gaseous first refrigerant by the high-temperature stage compressor 211, and then enters the high-temperature stage condenser 212 and is condensed into a high-pressure liquid first refrigerant, and the first refrigerant flowing out of the high-temperature stage condenser 212 may flow through the heat release portion 241 and transfer a part of heat to the second refrigerant in the heat absorption portion 242 in the heat release portion 241, so that the second refrigerant is warmed. The first refrigerant from the heat release portion 241 may flow through the bypass throttling device 218 again, be converted into a low-pressure first refrigerant, then enter the evaporation portion 231 to absorb heat and evaporate into a low-pressure gaseous first refrigerant, and finally flow into the suction inlet of the high-temperature-stage compressor 211, so as to form a complete high-temperature-stage refrigeration cycle.

The second refrigerant becomes a high-temperature and high-pressure gaseous second refrigerant under the action of the low-temperature stage compressor 251, then enters the middle condensation part 232, is condensed into a high-pressure liquid second refrigerant, flows through the low-temperature stage throttling device 255, is converted into a low-pressure gas-liquid two-phase second refrigerant, and then enters the low-temperature stage evaporation tube 256 to absorb heat and evaporate into a low-pressure gaseous second refrigerant, and it is noted that the "gaseous" herein refers to that most of the second refrigerant is gaseous, but not all of the second refrigerant is gaseous, that is, the second refrigerant after flowing through the low-temperature stage evaporation tube 256 may be carried with the liquid second refrigerant. If the second refrigerant flowing through the low-temperature-stage evaporator 256 carries a liquid second refrigerant, the low-temperature-stage refrigeration cycle is configured to enhance the heat exchange efficiency (i.e., enhance the heat recovery) between the low-temperature-stage throttling device and the heat-absorbing return air pipe. The second refrigerant from the low-temperature-stage evaporation tube 256 may flow through the heat absorbing portion 242, and absorb part of the heat of the first refrigerant having a higher temperature in the heat releasing portion 241 in the heat absorbing portion 242, so that the temperature thereof increases. The second refrigerant from the heat absorbing part 242 may flow into the suction port of the low temperature stage compressor 251 to form a complete low temperature stage refrigeration cycle.

The first refrigerant in the high-temperature-stage refrigeration cycle absorbs heat of the second refrigerant in the low-temperature-stage refrigeration cycle that flows through the condensation part 232 while flowing through the evaporation part 231, so that the second refrigerant in the condensation part 232 is cooled down and condensed into a liquid state. That is, the high-temperature-stage refrigeration cycle circuit may provide a pre-cooling function to the low-temperature-stage refrigeration cycle circuit using the first refrigerant, so that the second refrigerant in the low-temperature-stage refrigeration cycle circuit can be converted from a gaseous state to a liquid state. The second refrigerant absorbs heat and evaporates in the low-temperature-stage evaporation tube 256, and absorbs a large amount of heat, thereby realizing an effective refrigeration function at a lower temperature.

In the low-temperature-stage refrigeration cycle, the second refrigerant temperature in the section between the low-temperature-stage evaporation pipe 256 and the suction port of the low-temperature-stage compressor 251 is low. In the high temperature stage refrigeration cycle, the first refrigerant temperature in the section between the discharge port of the high temperature stage compressor 211 and the evaporation portion 231 is relatively high and higher than the second refrigerant temperature flowing through the heat absorption portion 242.

By arranging the heat exchange assembly 240, the second refrigerant flowing through the heat absorbing part 242 absorbs heat of the first refrigerant flowing through the heat releasing part 241, and the temperature of the second refrigerant in the low-temperature-stage refrigeration cycle loop is raised before the second refrigerant flows into the suction inlet of the compressor, so that the suction temperature of the low-temperature-stage compressor 251 can be increased, the cold loss caused by the excessively low suction temperature can be reduced or avoided, the refrigeration efficiency is improved, the condensation or frosting phenomenon around the suction inlet of the low-temperature-stage compressor 251 can be reduced or avoided, the series of problems of wet stroke, liquid impact, oil shortage of the low-temperature-stage compressor 251 and the like caused by the excessively low suction temperature can be reduced or avoided, and the operation performance of the cascade compression refrigeration system is improved. Compared with the scheme of arranging heat preservation cotton on the pipe section upstream of the suction inlet of the low-temperature-stage compressor 251, the consistency of product performance in mass production of the household small-sized refrigeration equipment 10 is improved.

The heat release portion 241 is disposed between the high-temperature-stage condenser 212 and the evaporation portion 231, and the first refrigerant flowing through the heat release portion 241 transfers heat to the second refrigerant flowing through the heat absorption portion 242, so that the supercooling degree of the first refrigerant can be increased, the refrigeration efficiency of the high-temperature-stage refrigeration cycle is improved, and the energy utilization efficiency of the entire refrigeration apparatus 10 is further improved.

The high temperature stage refrigeration cycle may further include: an electric switching valve 217, a cooling branch, a second cooling evaporator 222, an anti-dew tube 215, and a high-temperature-stage liquid storage pack. Wherein, the cooling branch circuit can be one or more. The cooling branches of this embodiment may be plural and arranged in parallel with each other.

The second cooling evaporator 222 is disposed between the heat-releasing portion 241 and the suction inlet of the high-temperature stage compressor 211, and is used for promoting the first refrigerant from the plurality of cooling branches to the suction inlet of the high-temperature stage compressor 211. The second cooling evaporator 222 is further configured to cause the first refrigerant flowing therethrough to absorb heat, so that the storage compartment 111 in which the second cooling evaporator 222 is located is cooled. The second refrigeration evaporator 222 may be configured to be disposed within an evaporator mounting cavity corresponding to the refrigeration compartment and configured to provide refrigeration to the refrigeration compartment.

The evaporation part 231 may be disposed between the heat emission part 241 and the second cooling evaporator 222, and a plurality of cooling branches may be disposed between the heat emission part 241 and the evaporation part 231. That is, the plurality of cooling branches may be located downstream of the heat radiating portion 241 and upstream of the evaporation portion 231, and the second cooling evaporator 222 may be located downstream of the evaporation portion 231 and upstream of the suction port of the high temperature stage compressor 211.

The cooling system comprises a plurality of cooling branches which are mutually connected in parallel, and each cooling branch is internally provided with a branch throttling device. The cooling branches may be two, three, four or five, or any other number. In this embodiment, the number of cooling branches may be three, including a first cooling branch, a second cooling branch, and a third cooling branch. The bypass restriction may be a capillary tube or an expansion valve, and the arrangement of the restriction is well known to those skilled in the art and will not be described in detail herein.

Wherein, the first cold supply branch is provided with a first cold supply evaporation tube 219 and a one-way valve 220 therein. Wherein the first cold feed evaporation pipe 219 is for causing the first refrigerant flowing therethrough to absorb heat. The first cooling evaporation tube 219 and the low-temperature stage evaporation tube 256 are used for cooling the same storage compartment 111. For example, the first cooling evaporator tube 219 may be configured with the low temperature stage evaporator tube 256 for placement within an evaporator mounting cavity corresponding to a cryogenic compartment and for cooling the cryogenic compartment. The first cold supply evaporation tube 219 and the low temperature stage evaporation tube 256 are arranged on the same fin group in a penetrating way. The first cooling evaporation tube 219 may form a double tube evaporator with the low temperature stage evaporation tube 256 and the fin group through which the two pass. That is, the double-tube evaporator has a first cold supply evaporation tube 219 and a low-temperature stage evaporation tube 256 therein, and two sets of evaporation tubes are provided. The first cooling evaporation pipe 219 may be disposed adjacent to each other, or may be disposed around each other, but is not limited thereto.

The first cooling evaporation tube 219 and the low-temperature-stage evaporation tube 256 are configured to be disposed in the same evaporator installation cavity corresponding to the same storage compartment 111, and are used for cooling the same storage compartment 111, so that the refrigeration efficiency of the storage compartment 111 can be improved, and the storage compartment 111 can be cooled down rapidly.

The first cold supply evaporation tube 219 and the low temperature stage evaporation tube 256 are utilized to form a double-tube evaporator, which is beneficial to improving the refrigeration efficiency of the double-tube evaporator, miniaturizing the structure of the double-tube evaporator, simplifying the integral structure of the refrigeration equipment 10 with the cascade compression refrigeration system and reducing the manufacturing cost.

The first cooling evaporation tube 219 is disposed between the heat release portion 241 and the evaporation portion 231, and the first cooling evaporation tube 219 causes the first refrigerant flowing therethrough to evaporate and absorb heat and cool the storage compartment 111, thereby fully utilizing the cold energy generated in the high-temperature-stage refrigeration cycle, improving the energy utilization efficiency of the high-temperature-stage refrigeration cycle, and further improving the energy utilization efficiency of the entire refrigeration equipment 10.

When the cascade compression refrigeration system starts to operate, the cooling process of the cryogenic chamber can be divided into an initial stage and a later stage, and the two stages are altogether. The initial stage may be a process of reducing the temperature of the cryogenic compartment from the ambient temperature to a first preset temperature, and the later stage may be a process of reducing the temperature of the cryogenic compartment from the first preset temperature to a second preset temperature, the first preset temperature being higher than the second preset temperature. The first preset temperature may be any value between-10 and-28 ℃, for example-18 ℃, and the second preset temperature may be any value between-40 and-80 ℃, for example-55 ℃. The first cool-supplying evaporation pipe 219 may be used to cool an initial stage, and the low-temperature stage evaporation pipe 256 may be used to cool a later stage.

In general, whether or not the evaporator supplies cold is determined by whether or not the refrigerant circulates therein. For example, whether the first refrigerant flows through the first cold feed evaporation pipe 219 may be controlled by controlling an electric switching valve 217 (to be described in detail later), thereby controlling whether the first cold feed evaporation pipe 219 is cold fed, and whether the second refrigerant flows through the low temperature stage evaporation pipe 256 may be controlled by controlling whether the low temperature stage compressor 251 is on, thereby controlling whether the low temperature stage evaporation pipe 256 is cold fed.

In some alternative embodiments, the first cold feed evaporation tube 219 and the low temperature stage evaporation tube 256 can also be used to be disposed within an evaporator mounting cavity corresponding to the temperature change compartment and to provide cold to the temperature change compartment. The temperature-changing chamber can selectively control the first cooling evaporation pipe 219 or the low-temperature-stage evaporation pipe 256 to independently cool according to actual needs, or control the first cooling evaporation pipe 219 and the low-temperature-stage evaporation pipe 256 to jointly cool, so that the temperature-changing chamber can obtain different refrigeration effects to meet different refrigeration demands.

A check valve 220 is disposed downstream of the first cooling evaporation pipe 219 for allowing only the first refrigerant from the first cooling evaporation pipe 219 to flow out in one direction. That is, in the first cooling branch, the check valve 220 is only used to allow the first refrigerant from the upstream thereof to pass through in one direction, and the check valve 220 can function to prevent the first refrigerant downstream of the check valve 220 from passing through in the reverse direction.

When the low temperature stage compressor 251 is operated, the temperature of the low temperature stage evaporation pipe 256 is low. Because the distance between the low-temperature-stage evaporation tube 256 and the first cold supply evaporation tube 219 is relatively short, the pipeline temperature of the first cold supply evaporation tube 219 is relatively low, and even is significantly lower than the temperature of other cold supply evaporators positioned downstream of the first cold supply evaporation tube 219 in the high-temperature-stage refrigeration cycle. The one-way valve 220 positioned at the downstream of the first cooling evaporation pipe 219 is arranged in the first cooling branch, so that the first refrigerant in other cooling evaporators positioned at the downstream of the first cooling evaporation pipe 219 can be prevented from flowing into the first cooling evaporation pipe 219 from the discharge outlet of the first cooling evaporation pipe 219, the reverse flow of the first refrigerant in the high-temperature-stage refrigeration cycle loop can be avoided, the effective flow of the first refrigerant is ensured, and the integral refrigeration efficiency is improved.

The second cooling branch may not be provided with an evaporation tube or an evaporator for cooling the storage compartment.

A third cooling evaporator 221 may be disposed in the third cooling branch, and the third cooling evaporator 221 may be configured to be disposed in an evaporator mounting cavity corresponding to the refrigerating compartment and to cool the refrigerating compartment.

An electric switching valve 217 having a plurality of valve ports for communicating with one cooling branch, respectively, the electric switching valve 217 being configured to adjust a flow path of the first refrigerant flowing therethrough by controllably opening or closing the valve ports. The electrically operated switching valve 217 serves to switch and control the flow direction of the first refrigerant such that the first refrigerant flowing therethrough is controllably flowed to one or more of the cooling branches. The electric switching valve 217 may be disposed upstream of the plurality of cooling branches and downstream of the heat release portion 241.

An anti-dew tube 215 is disposed between the high temperature stage condenser 212 and the cold leg for promoting the heat release of the first refrigerant flowing therethrough. A heat release portion 241 and an anti-dew tube 215 may be disposed between the high temperature stage condenser 212 and the cooling branch, and the relative positions of the heat release portion 241 and the anti-dew tube 215 may be set according to actual needs. For example, the heat radiation portion 241 may be provided between the high-temperature-stage condenser 212 and the dew-preventing pipe 215, or may be provided between the dew-preventing pipe 215 and the cooling branch. In the present embodiment, the dew prevention pipe 215 may be disposed between the heat emitting portion 241 and the cooling branch. The dew preventing pipe 215 may be used to be disposed at an edge portion around the door body of the refrigeration apparatus 10. When the cascade compression refrigerating system operates, the first refrigerant emits heat when flowing through the dew-proof pipe 215, so that the dew-proof pipe 215 heats up and generates heat, thereby reducing or avoiding the phenomenon of dew condensation on the edge of the door body of the refrigerating equipment 10, keeping the edge of the door body of the refrigerating equipment 10 dry, and avoiding the problems of poor sealing of the box body 110 and the like caused by rust on the edge of the door body.

The high temperature grade packages may include a first package up Wen Jidi and a second package up Wen Jidi, 223. A high Wen Jidi-liquid storage bag is disposed between the high-temperature-stage condenser 212 and the dew-proof tube 215, and is used for adjusting the amount of the first refrigerant required by other components (for example, the high-temperature-stage condenser 212, the evaporation part 231, or the evaporation tube or the evaporator for cooling) in the high-temperature-stage refrigeration cycle. Since the flow of the first refrigerant required for each component in the high temperature stage refrigeration cycle may be different under different operating conditions. A high Wen Jidi-head can controllably raise the liquid level as the first refrigerant flow required by other components in the high-temperature-level refrigeration cycle is reduced. The Wen Jidi-up-to-liquid package also allows for controlled lowering of the liquid level as the first refrigerant flow required by other components in the high-temperature-level refrigeration cycle increases. One liquid storage bag with the height Wen Jidi is a high-pressure liquid storage bag. When the high temperature stage refrigeration cycle is operating stably, the first refrigerant entering the high Wen Jidi-liquid storage bag is normally in a saturated liquid state.

The high Wen Jidi two liquid storage bags 223 are arranged between the second cold supply evaporator 222 and the suction inlet of the high-temperature-stage compressor 211. The high Wen Jidi two-liquid storage bag 223 can prevent the first refrigerant flowing to the suction inlet of the high-temperature-stage compressor 211 from carrying liquid first refrigerant, can also regulate the flow of the first refrigerant required by other components in the high-temperature-stage refrigeration cycle, and can also prevent the first refrigerant at the second refrigeration evaporator 222 from slowly migrating to the suction inlet of the high-temperature-stage compressor 211 when the high-temperature-stage refrigeration cycle system is shut down.

The high temperature stage refrigeration cycle may further include: a high-temperature-stage dry filter 216 provided between the dew-proof pipe 215 and the electric switching valve 217. The high temperature stage drier-filter 216 serves to filter impurities in the first refrigerant and prevent ice blockage.

In this embodiment, in the high-temperature-stage refrigeration cycle, the first refrigerant may sequentially flow through the discharge port of the high-temperature-stage compressor 211, the high-temperature-stage condenser 212, the heat release portion 241, the high Wen Jidi first liquid storage bag 214, the dew-proof pipe 215, the high-temperature-stage dry filter 216, the electric switching valve 217, the plurality of cooling branches (including the branch throttling device 218, the first cooling evaporation pipe 219, the check valve 220, the third cooling evaporator 221), the evaporation portion 231, the second cooling evaporator 222, the high Wen Jidi second liquid storage bag 223, and the suction port of the high-temperature-stage compressor 211, so as to form a complete cycle.

In some alternative embodiments, the position of the heat release portion 241 may be altered. For example, the heat radiation portion 241 may be provided between the discharge port of the high-temperature stage compressor 211 and the high-temperature stage condenser 212, or may be provided between the dew point preventing pipe 215 and the dry filter.

In alternative embodiments, the position of the evaporation portion 231 may be changed. The plurality of cooling branches may also be disposed between the heat radiating portion 241 and the second cooling evaporator 222, for example, the electric switching valve 217 and the cooling branch may be disposed between the dry filter and the second cooling evaporator 222, and the evaporation portion 231 may be disposed within the second cooling branch.

Fig. 2 and 3 are only illustrated with one embodiment in which the heat radiating portion 241 is disposed between the high temperature stage condenser 212 and the evaporating portion 231, and as for other installation positions, those skilled in the art will readily recognize on the basis of the present embodiment, and are not shown here one by one. As for the throttling means, fig. 2 and 3 are only illustrated as capillary tubes, but the throttling means in the present embodiment should not be regarded as being limited to capillary tubes only.

The low temperature stage refrigeration cycle may further include: a low temperature stage radiator 252, a low temperature stage dry filter 254, a low temperature stage throttle device 255, a low temperature stage liquid storage bag 257, and a heat absorption return air pipe section 258.

A low temperature stage radiator 252 is provided between the discharge port of the low temperature stage compressor 251 and the condensing part 232, for absorbing heat of the second refrigerant flowing therethrough. The low-temperature-stage radiator 252 allows the second refrigerant in the low-temperature-stage refrigeration cycle to be cooled in advance before flowing to the condensing part 232, ensuring that the second refrigerant is sufficiently condensed while flowing through the condensing part 232.

The low-temperature-stage throttle device 255 is provided between the condensation unit 232 and the low-temperature-stage evaporation pipe 256. The low temperature stage restriction 255 may also be a capillary tube or an expansion valve.

The low-temperature-stage dry filter 254 is provided between the condensing unit 232 and the low-temperature-stage throttle device 255, and functions to filter impurities in the second refrigerant and prevent ice blockage.

A heat absorbing return pipe section 258 is provided between the low temperature stage evaporation pipe 256 and the heat absorbing portion 242. At least a portion of the heat absorption and return air pipe section 258 and the low temperature stage throttling device 255 can be mutually abutted or sleeved, so that the second refrigerant flowing through the heat absorption and return air pipe section 258 absorbs the heat of the second refrigerant flowing through the low temperature stage throttling device 255, the energy utilization efficiency in the low temperature stage refrigeration cycle loop is improved, the energy utilization efficiency of the whole refrigeration equipment 10 is further improved, and the temperature of the second refrigerant flowing to the suction inlet of the low temperature stage compressor 251 is improved, so that the suction temperature of the low temperature stage compressor 251 is improved.

The heat absorption and return air pipe section 258 and the heat absorption part 242 are arranged on the flow path between the low-temperature-stage evaporation pipe 256 and the low-temperature-stage compressor 251, namely, the flow path between the low-temperature-stage evaporation pipe 256 and the low-temperature-stage compressor 251 is divided into two different pipe sections, the relative positions of the different pipe sections can be flexibly set, and the two different pipe sections can exchange heat with different positions in the low-temperature-stage refrigeration cycle loop respectively, so that the suction temperature of the low-temperature-stage compressor 251 is improved, and the energy utilization efficiency of the whole cascade compression refrigeration system is improved.

The heat absorption and return air pipe section 258 and the low-temperature-stage throttling device 255 can form a double-pipe heat exchanger, the low-temperature-stage throttling device 255 can be a pipe side of the double-pipe heat exchanger, and the heat absorption and return air pipe section 258 can be a shell side of the double-pipe heat exchanger. In alternative embodiments, the heat absorbing and returning pipe 258 and the low temperature stage restriction 255 may be two copper pipes that abut each other, wherein one copper pipe is the heat absorbing and returning pipe 258 and the other copper pipe is the low temperature stage restriction 255. The two copper pipes are mutually and closely arranged. And the contact part between the two copper pipes can be fixed by soldering so as to strengthen heat transfer. Aluminum foil can be wrapped on the outer parts of the two copper pipes.

The low-temperature-stage liquid storage bag 257 is disposed downstream of the low-temperature-stage evaporation tube 256 and between the low-temperature-stage evaporation tube 256 and the heat-absorbing return air tube 258. The low temperature stage receiver 257 can prevent the second refrigerant flowing to the suction port of the low temperature stage compressor 251 from carrying the liquid second refrigerant, can adjust the amount of the second refrigerant required for other components in the low temperature stage refrigeration cycle, and can prevent the second refrigerant at the low temperature stage evaporation tube 256 from slowly migrating to the suction port of the low temperature stage compressor 251 when the low temperature stage refrigeration cycle system is stopped.

In this embodiment, in the low-temperature-stage refrigeration cycle, the second refrigerant may sequentially flow through the discharge port of the low-temperature-stage compressor 251, the low-temperature-stage radiator 252, the condensation portion 232, the low-temperature-stage dry filter 254, the low-temperature-stage throttle device 255, the low-temperature-stage evaporation tube 256, the low-temperature-stage liquid storage bag 257, the heat absorption return tube segment 258, the heat absorption portion 242, and the suction port of the low-temperature-stage compressor 251, forming a complete cycle.

After the second refrigerant passes through the low-temperature radiator 252, the temperature may be close to the ambient temperature but still be the superheated gas, that is, the superheat degree of the second refrigerant may be reduced during the process of passing through the low-temperature radiator 252. The second refrigerant output from the condensation unit 232 is a high-pressure liquid second refrigerant, and after passing through the low-temperature-stage throttling device 255, the second refrigerant is changed into a low-temperature low-pressure second refrigerant. The second refrigerant output from the low temperature stage evaporator 256 enters the heat absorption return air pipe section 258 and absorbs heat from the second refrigerant flowing through the low temperature stage throttling device 255, and the temperature can be raised but the superheat degree is lower. After the second refrigerant enters the heat absorbing portion 242 of the heat exchange assembly 240, the temperature may be increased, and the degree of superheat may be increased accordingly.

The heat dissipation fan 280 is used for enabling air flow to flow through the high-temperature-stage condenser 212 and then through the low-temperature-stage radiator 252, or enabling air flow to flow through the low-temperature-stage radiator 252 and then through the high-temperature-stage condenser 212, or enabling air flow to flow through the low-temperature-stage radiator 252 and the high-temperature-stage condenser 212 respectively. The low temperature stage radiator 252 may be disposed adjacent to the high temperature stage condenser 212, and the heat radiation fan 280 may be disposed at one side of the low temperature stage radiator 252 and the high temperature stage condenser 212. The heat radiation fan 280 can increase the wind speed and the wind quantity flowing through the low-temperature-stage radiator 252 and the high-temperature-stage condenser 212 to promote the rapid heat radiation of the low-temperature-stage radiator 252 and the high-temperature-stage radiator, thereby enhancing the heat radiation effect and enabling the cascade compression refrigeration system and the refrigeration equipment 10 with the cascade compression refrigeration system to continuously work in a normal temperature range.

The temperature of the low temperature stage radiator 252 may be lower than the temperature of the high temperature stage condenser 212. The low-temperature-level radiator 252 and the high-temperature-level condenser 212 are arranged adjacent to each other, and the same heat radiation fan 280 is utilized to promote the formation of air flow which flows through the low-temperature-level radiator 252 and then through the high-temperature-level condenser 212, so that the heat radiation effect of the low-temperature-level radiator 252 and the high-temperature-level condenser 212 is ensured, the arrangement quantity of the heat radiation fans 280 is simplified, the structure miniaturization is facilitated, and the cascade compression refrigeration system of the embodiment can be applied to the household small refrigeration equipment 10.

The air blower 290 may be provided in plural numbers, and is provided corresponding to one evaporator installation chamber, and is provided corresponding to each storage compartment 111, for blowing cool air to each storage compartment 111. The plurality of air-supplying fans may include a first air-supplying fan, which may be disposed corresponding to the evaporator installation cavity in which the first cooling evaporation pipe 219 and the low temperature stage evaporation pipe 256 are disposed, for example, may be disposed at one side of the first cooling evaporation pipe 219 and the low temperature stage evaporation pipe 256, and may be used to guide the air flow flowing through the first cooling evaporation pipe 219 and the low temperature stage evaporation pipe 256 to the corresponding storage compartment 111.

In other alternative embodiments, the cascade compression refrigeration system may further include a heat exchange device disposed within the low temperature stage refrigeration cycle. A heat exchange device, comprising: a heat release member and a heat absorption member. The heat release member is disposed between the condensing unit 232 and the low-temperature-stage throttle device 255. The heat absorbing member is disposed between the low temperature level evaporation tube 256 and the suction inlet of the low temperature level compressor 251, and is configured to promote the second refrigerant flowing through the heat absorbing member to absorb the heat of the second refrigerant flowing through the heat releasing member, so that the second refrigerant is condensed in multiple stages and evaporated in multiple stages, so that the second refrigerant flowing out of the condensation part 232 is continuously condensed in the heat releasing member, and the second refrigerant flowing out of the heat releasing member can be fully condensed, and the second refrigerant flowing out of the low temperature level evaporation tube 256 is continuously evaporated in the heat absorbing member, thereby reducing the compression ratio of the low temperature level compressor 251 to a certain extent, reducing or avoiding the loss of cold energy caused by the excessively low suction temperature, improving the refrigeration efficiency, and avoiding condensation or frosting near the suction inlet of the low temperature level compressor 251.

The cascade compression refrigeration system of the present embodiment and the refrigeration apparatus 10 having the same, wherein the cascade compression refrigeration system includes a high-temperature-stage refrigeration cycle, a low-temperature-stage refrigeration cycle, and a heat exchange assembly 240. The heat exchange unit 240 includes a heat radiation portion 241 provided in the high-temperature-stage refrigeration cycle and located between the discharge port of the high-temperature-stage compressor 211 and the evaporation portion 231, and a heat absorption portion 242 provided in the low-temperature-stage refrigeration cycle and located between the low-temperature-stage evaporation tube 256 and the suction port of the low-temperature-stage compressor 251. The heat absorbing portion 242 is configured to promote the second refrigerant flowing through the heat absorbing portion to absorb heat of the second refrigerant flowing through the heat releasing portion 241, so that the temperature of the second refrigerant in the low-temperature-stage refrigeration cycle is raised before the second refrigerant flows into the suction port of the compressor, thereby improving the suction temperature of the low-temperature-stage compressor 251, reducing or avoiding the loss of cold energy caused by the excessively low suction temperature, improving the refrigeration efficiency, reducing or avoiding the condensation or frosting problem occurring in the accessories of the low-temperature-stage compressor 251, and improving the operation performance of the cascade compression refrigeration system.

By now it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been shown and described herein in detail, many other variations or modifications of the invention consistent with the principles of the invention may be directly ascertained or inferred from the present disclosure without departing from the spirit and scope of the invention. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims

1. An cascade compression refrigeration system comprising:

a high-temperature-stage refrigeration cycle circuit for circulating a first refrigerant, and having a high-temperature-stage compressor and an evaporation unit disposed therein;

a low-temperature-stage refrigeration cycle for circulating a second refrigerant, and having a low-temperature-stage compressor, a condensing part, and a low-temperature-stage evaporation pipe disposed therein; the evaporation part is used for promoting the first refrigerant flowing through the evaporation part to absorb heat of the second refrigerant flowing through the condensation part; and

A heat exchange assembly, comprising:

A heat release part arranged in the high-temperature-stage refrigeration cycle loop and positioned between the high-temperature-stage compressor discharge port and the evaporation part;

a heat absorption part which is arranged in the low-temperature-stage refrigeration cycle loop and is positioned between the low-temperature-stage evaporation pipe and the suction inlet of the low-temperature-stage compressor; the heat absorbing portion is for causing the second refrigerant flowing therethrough to absorb heat of the first refrigerant flowing through the heat releasing portion;

the high temperature stage refrigeration cycle circuit further includes:

A plurality of cold supply branches which are mutually connected in parallel, wherein each cold supply branch is internally provided with a branch throttling device; the plurality of cooling branches includes:

A first cooling branch having a first cooling evaporator tube disposed therein for causing the first refrigerant flowing therethrough to absorb heat; the first cooling evaporation pipe and the low-temperature-stage evaporation pipe are used for cooling the same storage compartment;

The first cooling evaporation pipe and the low-temperature-stage evaporation pipe are arranged in the evaporator mounting cavity corresponding to the temperature changing chamber and used for cooling the temperature changing chamber, and the first cooling evaporation pipe and the low-temperature-stage evaporation pipe are controlled to jointly supply cold.

2. The cascade compression refrigeration system of claim 1, wherein the high temperature stage refrigeration cycle further comprises:

the high-temperature-stage condenser is arranged between the high-temperature-stage compressor discharge port and the evaporation part, and the heat release part is positioned between the high-temperature-stage condenser and the evaporation part.

3. The cascade compression refrigeration system of claim 1, wherein

The first cooling evaporation pipe and the low-temperature-stage evaporation pipe are arranged on the same fin group in a penetrating mode.

4. The cascade compression refrigeration system of claim 1, wherein

And a one-way valve is arranged in the first cold supply branch and is arranged at the downstream of the first cold supply evaporation pipe and used for only allowing the first refrigerant from the first cold supply evaporation pipe to flow out in a one-way.

5. The cascade compression refrigeration system of claim 1, wherein the high temperature stage refrigeration cycle further comprises:

And a second cooling evaporator provided between the heat radiating portion and the high-temperature-stage compressor suction port, for causing the first refrigerant from the plurality of cooling branches to pass to the high-temperature-stage compressor suction port.

6. The cascade compression refrigeration system of claim 5, wherein

The evaporation part is arranged between the heat release part and the second cold supply evaporator; and

The plurality of cooling branches are arranged between the heat release part and the evaporation part.

7. The cascade compression refrigeration system of claim 5, wherein

The plurality of cooling branches are arranged between the heat release part and the second cooling evaporator; the plurality of cooling branches further includes:

the evaporation part is arranged in the second cooling branch.

8. The cascade compression refrigeration system of claim 1, wherein the high temperature stage refrigeration cycle further comprises:

The dew-proof pipe is arranged between the high-temperature-stage condenser and the cooling branch and is used for promoting the first refrigerant flowing through the dew-proof pipe to release heat; the heat release part is arranged between the high-temperature-stage condenser and the dew-proof pipe;

the liquid storage bag is high Wen Jidi and is arranged between the heat release part and the dew prevention pipe.

9. The cascade compression refrigeration system of claim 1, wherein the low temperature stage refrigeration cycle further comprises:

The low-temperature-stage throttling device is arranged between the condensing part and the low-temperature-stage evaporation pipe;

The heat absorption and return air pipe section is arranged between the low-temperature-stage evaporation pipe and the heat absorption part; at least part of the heat absorption air return pipe section and the low-temperature-stage throttling device are mutually abutted or sleeved, so that the second refrigerant flowing through the heat absorption air return pipe section absorbs heat of the second refrigerant flowing through the low-temperature-stage throttling device.

10. A refrigeration appliance comprising:

A case;

The cascade compression refrigeration system of any one of claims 1-9 disposed within the cabinet.