CN212253211U - Cascade compression refrigeration system and refrigeration equipment with same - Google Patents

Abstract

The utility model provides a cascade compression refrigerating system and refrigeration plant who has it, cascade compression refrigerating system includes: the high-temperature stage refrigeration cycle loop is used for circulating a first refrigerant; the low-temperature stage refrigeration circulation loop is used for circulating a second refrigerant and is internally provided with a low-temperature stage compressor and a low-temperature stage evaporation pipe; the low-temperature stage refrigeration cycle further includes: the first heat absorption air return pipe section is arranged between the low-temperature-stage evaporation pipe and a low-temperature-stage compressor suction port; the auxiliary heating device is used for heating the second refrigerant in the first heat absorption air return pipe section, so that the temperature of the second refrigerant in the low-temperature stage refrigeration cycle loop is raised before the second refrigerant flows into a suction inlet of the compressor, the suction temperature of the low-temperature stage compressor can be increased, the cold loss caused by too low suction temperature can be reduced or avoided, and the refrigeration efficiency is improved.

Description

Cascade compression refrigeration system and refrigeration equipment having the same

technical field

The utility model relates to the field of refrigeration, in particular to a cascade compression refrigeration system and refrigeration equipment having the same.

Background technique

Cascade compression refrigeration system usually consists of two separate refrigeration cycles, which are called high temperature stage refrigeration cycle (referred to as high temperature part) and low temperature stage refrigeration cycle (referred to as low temperature part). The high temperature part uses a first refrigerant with a relatively high evaporation temperature, and the low temperature part uses a second refrigerant with a relatively low evaporation temperature. The condensing evaporator uses the cold energy produced by the first refrigerant in the high temperature part to condense the second refrigerant vapor discharged from the compressor in the low temperature part, which is both the evaporator of the high temperature part and 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 return pipe to the compressor suction port is relatively low, so that the suction temperature of the compressor in the low-temperature part is low, which will cause the low-temperature stage compressor return pipe and air. Condensation or frost builds up around the suction port of the cryogenic stage compressor, resulting in a loss of cooling capacity. For small household refrigeration equipment, the cooling capacity loss of dozens or even a few watts will significantly reduce the cooling efficiency.

Therefore, how to increase the suction temperature of the compressor in the low temperature part has become a technical problem to be solved urgently by those skilled in the art.

Utility model content

An object of the present invention is to provide a cascade compression refrigeration system and refrigeration equipment having the same, which at least partially solve the above problems.

A further purpose of the utility model is to increase the suction temperature of the compressor in the low temperature stage refrigeration cycle in the cascade compression refrigeration system to prevent condensation or frost around the low temperature stage compressor return pipe and the suction port.

A further purpose of the present invention is to improve the consistency of product performance during mass production of small household refrigeration equipment.

A further object of the present invention is to improve the refrigeration efficiency of the storage compartment in the refrigeration equipment with the cascade compression refrigeration system.

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

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

The utility model provides a cascade compression refrigeration system and refrigeration equipment having the same, comprising: a high-temperature-level refrigeration cycle circuit for circulating a first refrigerant; a low-temperature-level refrigeration cycle circuit for circulating a second refrigerant, And a low-temperature stage compressor and a low-temperature stage evaporating tube are arranged in it; the low-temperature stage refrigerating cycle circuit also includes: a first heat-absorbing return pipe section, which is arranged between the low-temperature stage evaporating tube and the suction port of the low-temperature stage compressor; an auxiliary heating device , used to heat the second refrigerant in the first heat-absorbing return pipe section.

Optionally, the auxiliary heating device is an electric heating device, which is arranged on one side of the first heat-absorbing and return-gas pipe section or is wound on the first heat-absorbing and return-gas pipe section.

Optionally, the cascade compression refrigeration system further includes: a condensing evaporator, which has an evaporating part located in the high temperature stage refrigeration cycle circuit, and a condensing part located in the low temperature stage refrigeration cycle circuit; The first refrigerant of the first refrigerant absorbs the heat of the second refrigerant flowing through the condensing part; the low-temperature stage refrigeration cycle also includes: a second heat-absorbing and return-gas pipe section, which is arranged between the low-temperature stage evaporation tube and the first heat-absorbing and return-gas pipe section ; Low-temperature stage throttling device, which is arranged between the condensation part and the low-temperature stage evaporating tube; the second heat-absorbing return pipe section is used to promote the second refrigerant flowing through it to absorb the second refrigerant flowing through the low-temperature stage throttling device of heat.

Optionally, the high-temperature stage refrigeration cycle includes: a high-temperature stage compressor; a high-temperature stage condenser, which is arranged between the discharge port of the high-temperature stage compressor and the evaporation part; a plurality of cooling branches arranged in parallel with each other, each supplying cooling A branch throttling device is arranged in the branch; the plurality of cooling branches include: a first cooling branch, which is provided with a first cooling evaporation pipe, and the first cooling evaporation pipe is used to promote the flow through it. The first refrigerant absorbs heat; the first cooling-supplying evaporating tube and the low-temperature stage evaporating tube are used to supply cooling for the same storage compartment in the refrigeration equipment.

Optionally, the first cooling-supply evaporating tube and the low-temperature-level evaporating tube pass through the same fin group.

Optionally, the first cooling branch is also provided with a one-way valve, and the one-way valve is arranged downstream of the first cooling evaporating tube, and is used to allow only the first refrigerant from the first cooling evaporating tube to go in one direction. flow.

Optionally, the high-temperature stage refrigeration cycle circuit further includes: a second cooling evaporator, which is arranged between the high-temperature stage condenser and the suction port of the high-temperature stage compressor, and is used for promoting the first refrigerant from the plurality of cooling supply branches. It leads to the suction port of the high-temperature stage compressor; a plurality of cooling branches are arranged between the high-temperature stage condenser and the second cooling-supply evaporator.

Optionally, the high-temperature refrigeration cycle circuit further includes: an electric switching valve, which has a plurality of valve ports, the plurality of valve ports are respectively used to communicate with a cooling branch, and the electric switching valve is used to open or The valve port is closed to adjust the flow path of the first refrigerant flowing therethrough.

Optionally, the high temperature stage refrigeration cycle circuit further includes: an anti-dew pipe, which is arranged between the high temperature stage condenser and the cooling branch, and is used to promote the heat release of the first refrigerant flowing therethrough.

According to another aspect of the present invention, a refrigeration device is also provided, comprising: a box body; and the cascade compression refrigeration system according to any one of the above, which is arranged in the box body.

The cascade compression refrigeration system of the utility model and the refrigeration equipment having the same, wherein the cascade compression refrigeration system comprises a high temperature stage refrigeration cycle circuit and a low temperature stage refrigeration cycle circuit. The low-temperature stage refrigeration cycle includes a first heat-absorbing return pipe section and an auxiliary heating device, and the auxiliary heating device is used for heating the second refrigerant in the first heat-absorbing return pipe section, so that the second refrigerant in the low-temperature stage refrigeration cycle is refrigerated The refrigerant heats up before flowing into the suction port of the compressor, thereby increasing the suction temperature of the low-temperature stage compressor, reducing or avoiding the loss of cooling capacity caused by the low suction temperature, improving the refrigeration efficiency, and reducing or avoiding the suction of the low-temperature stage compressor. Condensation or frost occurs around the mouth, which improves the performance of the cascade compression refrigeration system.

Further, in the cascade compression refrigeration system of the present invention and the refrigeration equipment having the same, the auxiliary heating device is used to heat the first heat-absorbing and return-air pipe section, compared with the scheme of arranging thermal insulation cotton on the heat-absorbing and return-air pipe section, The consistency of product performance during mass production of small household refrigeration equipment is improved.

Further, in the cascade compression refrigeration system of the present invention and the refrigeration equipment having the same, wherein the first cooling-supply evaporating tube and the low-temperature evaporating tube in the high-temperature stage refrigeration cycle loop are penetrated on the same fin group, and The first cooling-supply evaporating tube and the low-temperature-level evaporating tube are used to supply cooling to the same storage compartment, which can improve the refrigeration efficiency of the storage compartment and make the storage compartment cool down rapidly.

Further, in the cascade compression refrigeration system of the present invention and the refrigeration equipment having the same, wherein the first cooling evaporation tube is arranged between the high temperature stage condenser and the evaporation part, and the second refrigeration evaporator is arranged in the evaporation section. Between the suction port of the high-temperature stage compressor and the suction port of the high-temperature stage compressor, each evaporator or evaporating tube promotes the first refrigerant flowing through it to evaporate and absorb heat and provide cooling for the storage compartment, which improves the energy utilization efficiency of the high-temperature stage refrigeration cycle. Thus, the energy utilization efficiency of the entire refrigeration equipment is improved.

Further, in the cascade compression refrigeration system of the present invention and the refrigeration equipment having the same, a low-temperature stage throttling device and a second heat-absorbing return pipe section are also arranged in the low-temperature stage refrigerating cycle circuit, wherein the low-temperature stage throttling device is provided. It is arranged between the condensing part and the low-temperature-level evaporation tube, the second heat-absorbing and return-gas pipe section is arranged between the low-temperature-level evaporation tube and the first heat-absorbing and return-gas pipe section, and at least part of the second heat-absorbing and return-gas pipe section is connected to the low-temperature stage section. The flow device is closely arranged, so that the second refrigerant flowing through the second heat-absorbing return pipe section absorbs the heat of the second refrigerant flowing through the low-temperature stage throttling device, and the energy utilization efficiency in the low-temperature stage refrigeration cycle is improved. , thereby improving the energy utilization efficiency of the entire refrigeration equipment.

The above and other objects, advantages and features of the present invention will be more apparent to those skilled in the art from the following detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of example and not limitation with reference to the accompanying drawings. The same reference numbers in the figures designate the same or similar parts or parts. It will be understood by those skilled in the art that the drawings are not necessarily to scale. In the attached picture:

1 is a schematic diagram of a refrigeration equipment with a cascade compression refrigeration system according to an embodiment of the present invention;

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

Fig. 3 is the corresponding pressure-enthalpy diagram of the low-temperature stage refrigeration cycle in the operating state of the cascade compression refrigeration system shown in Fig. 2;

4 is a schematic diagram of a cascade compression refrigeration system according to another embodiment of the present invention.

Detailed ways

FIG. 1 is a schematic diagram of a refrigeration apparatus having a cascade compression refrigeration system according to an embodiment of the present invention.

The refrigeration device 10 may be a small household refrigeration device for storing food, medicine, or other items, for example, a refrigerator or a freezer.

Although the cascade compression refrigeration system has been involved in large-scale refrigeration equipment, however, due to the excessive operation noise and high energy consumption of the existing cascade compression refrigeration system, the cascade compression refrigeration in the prior art is The system has not been able to be applied to small household refrigeration equipment.

The cascade compression refrigeration system of this embodiment is especially suitable for small household refrigeration equipment 10 .

The refrigeration device 10 in this embodiment takes a refrigerator as an example. The refrigeration equipment 10 with the cascade compression refrigeration system may be a refrigerator with a cryogenic function.

The refrigeration equipment 10 may generally include: a casing 110 and a cascade compression refrigeration system disposed in the casing 110 . A storage compartment 111 for storing articles is also formed in the box body 110 . In this embodiment, there may be a plurality of storage compartments 111 , and may include, for example, a refrigerator compartment, a freezer compartment (which is a common freezer compartment), a temperature-changing compartment and/or a cryogenic compartment. In some other optional embodiments, the storage compartment 111 may be one, for example, may be a cryogenic compartment or a temperature-changing compartment. A plurality of evaporator installation cavities for installing the evaporator may also be formed in the box body 110 , and the evaporator installation cavities may be arranged on the back, side, top or bottom of the storage compartment 111 .

2 is a schematic diagram of a cascade compression refrigeration system according to an embodiment of the present invention, and the direction of the arrows in the figure shows the direction of heat transfer.

The cascaded compression refrigeration system may be a two-stage cascaded circulation system, a three-stage cascaded circulation system, or a four-stage cascaded circulation system, and the number of cascaded stages is not specifically limited herein. This embodiment only takes a cascaded compression refrigeration system with a two-stage cascaded circulation system as an example, and on this basis, those skilled in the art should be fully capable of expanding.

The cascade compression refrigeration system may include: a high temperature stage refrigeration cycle, a low temperature stage refrigeration cycle, a condensing evaporator, an auxiliary heating device, and may further include: a cooling fan 280 and an air supply fan 290 . The high-temperature stage refrigeration circulation 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.

The high temperature stage refrigeration cycle is used for circulating the first refrigerant. A high temperature stage compressor 211 may be provided in the high temperature stage refrigeration cycle. The low-temperature stage refrigeration cycle circuit is used for circulating the second refrigerant, and a low-temperature stage compressor 251 and a low-temperature stage evaporating tube 256 are arranged therein. The low-temperature evaporating tube 256 is used to promote the second refrigerant flowing therethrough to absorb the heat in the storage compartment 111 , so as to cool the storage compartment 111 .

The condensing evaporator has an evaporating part 231 located in a high temperature stage refrigeration cycle circuit and a condensing part 232 located in a low temperature stage refrigeration cycle circuit. The evaporation part 231 is used to cause the first refrigerant flowing therethrough to absorb the heat of the second refrigerant flowing through the condensation part 232 . The condensing part 232 may be located between the discharge port of the low temperature stage compressor 251 and the low temperature stage evaporation pipe 256 .

The high temperature stage refrigeration cycle further includes: a high temperature stage condenser 212 disposed between the discharge port of the high temperature stage compressor 211 and the evaporation part 231 .

That is, the high temperature stage refrigeration cycle may include: a high temperature stage compressor 211 and a high temperature stage condenser 212 , and the low temperature stage refrigeration cycle loop may include: a low temperature stage compressor 251 and a low temperature stage evaporating tube 256 .

In some alternative embodiments, the condensing evaporator may be a jacket and tube heat exchanger. The casing heat exchanger is made of two standard tubes of different sizes that are connected to each other to form concentric circular casings. The outer channel is called the shell side, and the inner channel is called the tube side. Two different media can flow in the opposite direction (or in the same direction) in the shell side and the tube side to achieve the effect of heat exchange. The evaporation part 231 can be on the shell side, and the condensation part 232 can be on the tube side. In some other optional embodiments, the condensation evaporator may be two copper tubes abutting against each other, wherein one copper tube is the evaporation part 231 and the other copper tube is the condensation part 232 . The two copper pipes are placed against each other. The contact part between the two copper pipes can be fixed by soldering to enhance heat transfer. The outside of the two copper pipes can be wrapped with aluminum foil.

Refrigerant, also known as refrigerant, usually completes energy conversion by phase change, and is a working substance that circulates in the refrigeration system of the refrigeration equipment 10. Its working principle is: the refrigerant absorbs the heat of the cooled substance in the evaporator Evaporation, in the condenser, transfers the absorbed heat to the surrounding air or water, and is cooled into a liquid, and the reciprocating cycle achieves the effect of refrigeration by means of the change of state. According to the size of the condensation pressure at room temperature and the evaporation temperature at atmospheric pressure, the refrigerants can be roughly divided into the following three categories: high temperature refrigerants, medium temperature refrigerants and low temperature refrigerants. "High temperature" and "low temperature" in "high temperature stage refrigeration cycle" and "low temperature stage refrigeration cycle" are relative terms. Relatively speaking, the evaporation of the first refrigerant flowing in the high temperature stage refrigeration cycle The temperature is higher than the evaporation temperature of the second refrigerant flowing in the low-temperature stage refrigeration cycle.

According to the composition of refrigerants, refrigerants can be roughly divided into the following three categories: pure working refrigerants, azeotropic refrigerants and non-azeotropic refrigerants. A pure working refrigerant, also called a single refrigerant, refers to a refrigerant formed by a single component substance. Azeotropic refrigerant is a refrigerant that is composed of two or more mutually soluble single-component substances mixed at room temperature according to a certain mass ratio or volume ratio. Its properties are the same as those of a single refrigerant. It has a constant evaporation temperature under the same pressure, and the components of the gas and liquid phases are the same. Non-azeotropic refrigerant, a solution composed of two or more single refrigerants that do not form an azeotropic solution with each other. When the solution is heated, under a certain evaporation pressure, the ratio of the more volatile components to evaporate Large, the proportion of non-volatile components to evaporate is small, the composition of the gas and liquid phases is different, and the temperature of the refrigerant changes during the evaporation process, and it also has similar characteristics during the condensation process.

The first refrigerant in this 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 stage refrigeration cycle in stable operation is configured to be 2 ~ 11bar, and the absolute pressure range of the low-pressure side of the low-temperature stage refrigeration cycle under the stable operation state is configured to be 0.2 ~ 1.1bar.

Wherein, the high pressure side in the low temperature stage refrigeration cycle refers to: in the flow direction of the second refrigerant, between the discharge port of the low temperature stage compressor 251 and the upstream of the suction port of the low temperature stage throttling device 255 in the low temperature stage refrigeration cycle loop part. The low pressure side in the low temperature stage refrigeration cycle refers to the part between the downstream of the discharge port of the low temperature stage throttling device 255 and the suction port of the low temperature stage compressor 251 in the flow direction of the second refrigerant in the low temperature stage refrigeration cycle loop . Normally, the absolute pressure of the high-pressure side of the low-temperature stage refrigeration cycle can be detected by detecting a preset position close to 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 can be obtained by detecting the absolute pressure near the low-temperature stage compressor 251. It is detected at a preset position upstream of the suction port of the stage compressor 251 . In some optional embodiments, if the low temperature stage compressor 251 has a process port for directly communicating with the low pressure cavity inside the low temperature stage compressor 251 , the above-mentioned absolute pressure on the low pressure side can be obtained by detecting at the process port.

The low-temperature refrigeration cycle can enter a stable operation state after a certain period of time when it is turned on. In this embodiment, it is judged whether the low-temperature-stage refrigeration cycle is in a stable operation state by the absolute pressure of the low-pressure side of the low-temperature-stage refrigeration cycle. After the low temperature stage refrigeration cycle is turned on, the absolute pressure of the low pressure side of the low temperature stage refrigeration cycle can be continuously collected. If, within the first set time, the ratio between the maximum value of the absolute pressure on the low-pressure side of the low-temperature stage refrigeration cycle and the average value of the absolute pressure on the low-pressure side of the low-temperature stage refrigeration cycle is less than the first preset ratio, and If the ratio between the minimum value of the absolute pressure on the low-pressure side of the low-temperature stage refrigeration cycle and the average value of the absolute pressure on the low-pressure side of the low-temperature stage refrigeration cycle is greater than the second preset ratio, it means that within the first set time The low-temperature stage refrigeration cycle circuit is in a stable operation state. Wherein, the average value of the absolute pressure on the low-pressure side of the low-temperature-stage refrigeration cycle refers to the highest value of the absolute pressure on the low-pressure side of the low-temperature-stage refrigeration cycle within the first set time and the absolute pressure on the low-pressure side of the low-temperature-stage refrigeration cycle. The arithmetic mean of the lowest value of the pressure magnitude. The first set time can be any time in the range of 0.25-1 h, for example, it can be 0.25 h, 0.5 h, or 1 h, preferably, it can be 0.25 h or 0.5 h. The first preset ratio can be any value in the range of 1-1.2, for example, it can be 1, 1.1, or 1.2, preferably, it can be 1.1, and the second preset ratio can be any value in the range of 0.85-0.95, For example, it may be 0.85, 0.9 or 0.95, preferably, it may be 0.9. In this embodiment, the absolute pressure of the low-pressure side of the low-temperature refrigeration cycle can be collected after the test bag (GB/T8059) is put into the storage compartment 111 of the refrigeration equipment 10, so as to monitor the stable operation of the low-temperature refrigeration cycle state.

Since the discharge 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. When the circulation loop is running, the low-temperature stage compressor 251 has lower suction pressure and lower discharge pressure, which can effectively reduce the noise generated during operation and reduce the energy consumption during operation, which can be suitable for small household refrigeration. device 10.

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

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

In some optional embodiments, the value range of the lower limit value of the absolute pressure of the low-pressure side when the low-temperature stage refrigeration cycle circuit is in a stable operation state may be configured to be 0.2-0.8 bar, or 0.2-0.6 bar, or 0.2-0.5 bar, or 0.2 to 0.4 bar.

The low temperature refrigeration cycle can be preset with multiple refrigeration temperatures, for example, the refrigeration temperature can be, but not limited to, 5°C, -5°C, -18°C, -40°C, -60°C or -80°C. The low-temperature stage refrigeration cycle can achieve its own stable operation state when it operates according to different refrigeration temperatures. Depending on the refrigeration temperature, the absolute pressure on the low-pressure side of the low-temperature refrigeration cycle in a stable operation state can be different. The absolute pressure of the low-pressure side when the low-temperature stage refrigeration cycle is in a stable operation state reaches the lower limit value within a set time period before the low-temperature stage refrigeration cycle stops. Depending on the refrigeration temperature, the lower limit of the absolute pressure on the low-pressure side of the low-temperature refrigeration cycle under stable operation can be different, but all can be within 0.2 to 0.8 bar, or 0.2 to 0.6 bar, or 0.2 to 0.5 bar, or 0.2 ~ 0.4bar range.

The minimum absolute pressure on the low-pressure side of the low-temperature refrigeration cycle in stable operation can be any value within the range of 0.2 to 0.8 bar, for example, it can be 0.2 bar, 0.3 bar, 0.4 bar, 0.5 bar, 0.6 bar, 0.7 bar, Or 0.8bar.

The evaporation temperature range of the second refrigerant on the low pressure side when the low temperature stage refrigeration cycle circuit is in a stable operation state can be configured to be -111 to -35°C. 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 evaporation temperature of the second refrigerant in the low-temperature evaporating tube 256 can reach below -60°C, or can even reach below -80°C, which can be used to create -60°C for the storage compartment 111 in the small household refrigeration equipment 10 Even the low temperature of about -80°C improves the fresh-keeping ability of the small household refrigeration equipment 10 .

In this embodiment, the evaporation temperature range of the second refrigerant on the low pressure side when the low temperature stage refrigeration cycle is in a stable operation state can be configured to be -80 to -35°C, or -75 to -40°C.

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

The cryogenic stage compressor 251 may be an R600a compressor. When the existing R600a compressor is applied to the low-temperature stage refrigeration cycle circuit, the low-temperature lubricating oil can be replaced in the R600a compressor, the process is simple and the cost is low. Since the R600a compressor has low operating noise and high energy efficiency, the combination of the R600a compressor and the R290 refrigerant can reduce the noise of the low-temperature stage refrigeration cycle and improve the energy-saving effect.

The model of the low-temperature stage compressor 251 is not limited to this, as long as it has the above-mentioned working performance, it can be used as the low-temperature stage compressor 251 .

For example, the absolute pressure of the high-pressure side of the low-temperature refrigeration cycle in a stable operation state may be 3.022 bar, and the absolute pressure of the low-pressure side may be 0.368 bar. The second refrigerant may be R290 refrigerant. The condensing temperature of the second refrigerant on the high-pressure side of the low-temperature stage refrigeration cycle can be -12.1°C, and the evaporation temperature on the low-pressure side can be -62.8°C, so that the low-temperature stage refrigeration cycle can be a storage compartment during operation. 111 creates a low temperature environment around -55°C. The absolute pressure of the low-pressure side of the low-temperature stage refrigeration cycle in a stable operation state can also be 0.287 bar, and the evaporation temperature of the second refrigerant on the low-pressure side in the low-temperature stage refrigeration cycle can be -67.2 ℃, so that the low-temperature stage During the operation of the refrigeration cycle, a low temperature environment of about -60° C. can be created for the storage compartment 111 .

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

The condensing temperature of the second refrigerant on the high pressure side in the low temperature stage refrigeration cycle can be -16°C, and the evaporation temperature on the low pressure side can be -72°C, so that the low temperature stage refrigeration cycle can be a storage compartment during operation. 111 creates a low temperature environment around -65°C.

In some other optional embodiments, the evaporation temperature range of the second refrigerant on the low pressure side when the low temperature stage refrigeration cycle circuit is in a stable operation state can also be configured to be -111°C to -50°C.

The second refrigerant may be a non-azeotropic refrigerant, wherein the second refrigerant may include the first component. The standard boiling point range of the first component can be configured to be -60 to 0°C, or -50 to 0°C, or -45 to 0°C, or -15 to 0°C. The range of the mass fraction of the first component in the second refrigerant may be configured to be 20% to 80%.

For example, the second refrigerant may include R600a refrigerant and R170 refrigerant, wherein the first component may be R600a refrigerant, and the mass fraction of R600a refrigerant in the second refrigerant may range from 30% to 80%, It may be 40% to 60%. Alternatively, the second refrigerant may include R600 refrigerant and R170 refrigerant, wherein the first component may be R600 refrigerant, and the mass fraction of R600 refrigerant in the second refrigerant may range from 40% to 80%. Alternatively, the second refrigerant may include R600a refrigerant and R1150 refrigerant, wherein the first component may be R600a refrigerant, and the mass fraction of R600a refrigerant in the second refrigerant may range from 40% to 80%. Or the second refrigerant may include R600 refrigerant and R1150 refrigerant, wherein the first component may be R600 refrigerant, and the mass fraction of R600 refrigerant in the second refrigerant may range from 50% to 80%. Or the second refrigerant may include R290 refrigerant and R170 refrigerant, wherein the first component may be R290 refrigerant, and the mass fraction of R290 refrigerant in the second refrigerant may range from 50% to 70%. Or the second refrigerant may include R290 refrigerant and R1150 refrigerant, wherein the first component may be R290 refrigerant, and the mass fraction of R290 refrigerant in the second refrigerant may range from 70% to 80%. Or the second refrigerant may include 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 range from 60% to 80%. Or the second refrigerant may include 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 range from 70% to 80%.

The ODP (Ozone Depletion Potential, used to represent the ozone depletion potential) value of the second refrigerant can be configured as 0, and the GWP ₁₀₀ of the second refrigerant (calculated based on 100 years of GWP, denoted as GWP ₁₀₀ , where GWP is GlobalWarming Potential ) Abbreviation for Global Warming Potential) value can be configured to be less than or equal to 200.

The evaporation temperature range of the first refrigerant on the low pressure side when the high temperature refrigeration cycle is in a stable operation state can be configured to be -40°C to 0°C, or -35°C to -10°C, or -30°C to -15°C. 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 second refrigerant in the low temperature stage refrigeration cycle The condensing temperature range of the high pressure side in the circuit may be -25°C to -5°C.

The first refrigerant in the high temperature stage refrigeration cycle absorbs the heat of the second refrigerant in the low temperature stage refrigeration cycle passing through the condensation part 232 when flowing through the evaporation part, 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 can provide a pre-cooling function to the low temperature stage refrigeration cycle by using the first refrigerant, so that the second refrigerant in the low temperature stage refrigeration cycle can be converted from a gaseous state to a liquid state. The second refrigerant absorbs heat and evaporates in the low-temperature evaporating tube 256, and can absorb a large amount of heat, thereby realizing an effective refrigeration function at a lower temperature.

For example, the first refrigerant may be the R600a refrigerant, and the high temperature stage compressor 211 may be the 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 part (low pressure side) of the high temperature stage refrigeration cycle can absorb the heat of the second refrigerant flowing through the condensation part 232 (high pressure side) of the low temperature stage refrigeration cycle, so that it flows through the condensing part 232 The second refrigerant is condensed.

In the low temperature refrigeration cycle, when the ambient temperature is configured as a common indoor temperature, the common indoor temperature can be any value in the range of 7 to 40 °C, and the suction temperature of the low temperature compressor 251 is in the range of 10 to 38 °C. When the suction superheat degree of the low-temperature stage compressor 251 is 80-95K (K is the unit of thermodynamic temperature), the discharge temperature of the low-temperature stage compressor 251 can be configured to be less than or equal to 110°C, and the shell of the low-temperature stage compressor 251 The temperature can be configured to be 110°C or less. In some other optional embodiments, when the suction temperature of the low-temperature stage compressor 251 is in the range of 15-35°C, the suction superheat of the low-temperature stage compressor 251 is 80-85K (K is a unit of thermodynamic temperature). In this case, the discharge temperature of the low temperature stage compressor 251 can be configured to be less than or equal to 100°C, and the shell temperature of the low temperature stage compressor 251251 can be configured to be less than or equal to 100°C.

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

There is no injection cooling circuit in the low temperature refrigeration cycle.

The low-temperature stage refrigeration cycle may further include: a first heat-absorbing return pipe section 242 . The first heat-absorbing and return-gas pipe section 242 is arranged between the low-temperature stage evaporating tube 256 and the suction port of the low-temperature stage compressor 251 . The auxiliary heating device 243 is used for heating the second refrigerant in the first heat-absorbing return pipe section 242 .

The auxiliary heating device 243 may be an electric heating device, for example, an electric heating wire. The auxiliary heating device 243 may be disposed on one side of the first heat-absorbing and return-gas pipe section 242 or wound on the first heat-absorbing and return-gas pipe section 242 . The auxiliary heating device 243 may have a heating part arranged in abutment with the first heat-absorbing return pipe section 242 and a driving part for generating heat. The auxiliary heating device 243 transfers heat to the second refrigerant flowing through the first heat-absorbing and return-gas pipe section 242 , and warms the second refrigerant in the first heat-absorbing and return-gas pipe section 242 .

In some optional embodiments, the first refrigerant becomes a high-temperature and high-pressure gaseous first refrigerant under the action of the high-temperature stage compressor 211 , and then enters the high-temperature stage condenser 212 and condenses into a high-pressure liquid first refrigerant , the first refrigerant flowing out from the high-temperature stage condenser 212 can flow through the branch throttling device 218 and be converted into a low-pressure gas-liquid two-phase first refrigerant, and then enter the evaporating part 231 of the condensing evaporator to absorb heat and evaporate into a The low-pressure gaseous first refrigerant finally flows into the suction port of the high-temperature stage compressor 211 to form a complete high-temperature stage refrigeration cycle.

FIG. 3 is a corresponding pressure-enthalpy diagram when the low-temperature stage refrigeration cycle in the cascade compression refrigeration system shown in FIG. 2 is in an operating state. The ordinate in the figure represents the absolute pressure, and the abscissa represents the specific enthalpy.

The low-temperature stage compressor 251 sucks the second refrigerant at normal temperature and low pressure (corresponding to point 1 in FIG. 2 and FIG. 3 ), and the second refrigerant becomes a high-temperature and high-pressure gaseous second refrigerant under the action of the low-temperature stage compressor 251 ( corresponds to point 2 in Figures 2 and 3). The second refrigerant flowing out from the discharge port of the low-temperature stage compressor 251 can enter the condensing part in the condensing evaporator, and be condensed into a high-pressure liquid second refrigerant (corresponding to point 4 in FIG. 2 and FIG. 3 ), and then flow again After passing through the low-temperature stage throttling device 255, it is converted into a low-pressure gas-liquid two-phase second refrigerant (corresponding to point 5 in FIG. 2 and FIG. 3), and then enters the low-temperature stage evaporating tube 256 to absorb heat and evaporate into a low-pressure gaseous second refrigerant. Secondary refrigerant (corresponding to point 6 in Figures 2 and 3). The second refrigerant from the low-temperature evaporating tube 256 can flow through the first heat-absorbing return pipe section 242 and absorb part of the heat of the auxiliary heating device 243 in the first heat-absorbing return pipe section 242 to increase its own temperature. The second refrigerant from the first heat-absorbing return pipe section 242 can flow into the suction port of the low-temperature stage compressor 251 to form a complete low-temperature stage refrigeration cycle.

By arranging the first heat-absorbing return pipe section 242 and the auxiliary heating device 243, the second refrigerant flowing through the first heat-absorbing return pipe section 242 can absorb the heat of the auxiliary heating device 243, and make the second refrigerant in the low-temperature stage refrigeration cycle loop. The temperature of the secondary refrigerant is raised before flowing into the suction port of the compressor, so that the suction temperature of the low-temperature stage compressor 251 can be increased, the loss of cooling capacity caused by the low suction temperature can be reduced or avoided, the cooling efficiency can be improved, and the low-temperature stage compressor can be reduced or avoided. Condensation or frost occurs around the suction port of the compressor 251, and it can also reduce or avoid a series of problems such as wet stroke, liquid hammer, and oil shortage of the low-temperature compressor 251 caused by excessively low suction superheat, which improves the recovery time. Operational performance of stacked compression refrigeration systems.

The cascade compression refrigeration system of the present embodiment and the refrigeration equipment 10 having the same use the auxiliary heating device 243 to heat the first heat-absorbing and return-gas pipe section 242. The consistency of product performance during mass production of the small household refrigeration equipment 10 is improved.

The first refrigerant in the high-temperature stage refrigeration cycle absorbs the heat of the second refrigerant in the low-temperature stage refrigeration cycle flowing through the condensing part when flowing through the evaporation part 231, so that the second refrigerant in the condensing part cools down and condenses for liquid. That is, the high temperature stage refrigeration cycle can provide a pre-cooling function to the low temperature stage refrigeration cycle by using the first refrigerant, so that the second refrigerant in the low temperature stage refrigeration cycle can be converted from a gaseous state to a liquid state. The second refrigerant absorbs heat and evaporates in the low-temperature evaporating tube 256, and can absorb a large amount of heat, thereby realizing an effective refrigeration function at a lower temperature.

The low temperature refrigeration cycle loop may further include: a low temperature radiator 252 , a low temperature drying filter 254 , a low temperature throttling device 255 , a low temperature liquid storage bag 257 , and a second heat-absorbing return pipe section 258 .

The low temperature stage throttling device 255 is arranged between the condensation part and the low temperature stage evaporation tube 256 . The cryogenic stage throttling device 255 may also be a capillary tube or an expansion valve.

The second heat-absorbing return pipe section 258 is arranged between the low-temperature stage evaporating tube 256 and the suction port of the low-temperature stage compressor 251 . At least part of the heat-absorbing return pipe section and the low-temperature stage throttling device 255 can be placed against each other or sleeved with each other, so that the second refrigerant flowing through the second heat-absorbing and return-gas pipe section 258 absorbs and flows through the low-temperature stage throttling device 255 The heat of the second refrigerant increases the energy utilization efficiency in the low-temperature stage refrigeration cycle, thereby improving the energy utilization efficiency of the entire refrigeration equipment 10, and is conducive to improving the flow of the second refrigerant to the suction port of the low-temperature stage compressor 251. temperature, thereby increasing the suction superheat of the low-temperature stage compressor 251.

It is worth noting that the second refrigerant flowing through the low-temperature stage evaporating tube 256 may carry a liquid second refrigerant. If the second refrigerant flowing through the low-temperature stage evaporating tube 256 carries a liquid second refrigerant, the low-temperature stage refrigeration cycle is configured to strengthen the connection between the low-temperature stage throttling device 255 and the second heat-absorbing return pipe section 258 . Heat exchange efficiency (ie, enhanced heat recovery).

The second heat-absorbing and returning pipe section 258 may be disposed between the low-temperature stage evaporation pipe 256 and the first heat-absorbing and returning pipe section 242 , that is, the first heat-absorbing and returning pipe section 242 is disposed downstream of the second heat-absorbing and returning pipe section 258 , and is located between the second heat-absorbing return pipe section 258 and the compressor suction port.

The second heat-absorbing return pipe section 258 and the low-temperature stage throttling device 255 may form a casing heat exchanger, the low-temperature stage throttling device 255 may be the tube side of the casing heat exchanger, and the second heat-absorbing return pipe section 258 may is the shell side of the casing heat exchanger. In some other optional embodiments, the second heat-absorbing and return-gas pipe section 258 and the low-temperature stage throttling device 255 may be two copper pipes abutting against each other, wherein one copper pipe is the second heat-absorbing and return-gas pipe section 258 , and the other copper tube is the low temperature throttling device 255 . The two copper pipes are placed against each other. The contact part between the two copper pipes can be fixed by soldering to enhance heat transfer. The outside of the two copper pipes can be wrapped with aluminum foil.

The second heat-absorbing return pipe section 242 and the second heat-absorbing return pipe section 258 are arranged on the flow path between the low-temperature stage evaporating tube 256 and the low-temperature stage compressor 251, that is, the connection between the low-temperature stage evaporating tube 256 and the low-temperature stage compressor 251 is set. The flow path is divided into two different pipe sections, and the relative positions of the different pipe sections can be flexibly set, so that the two different pipe sections can exchange heat with the corresponding positions in the auxiliary heating device and the low-temperature stage refrigeration cycle respectively. The suction temperature of the low-temperature stage compressor 251 is improved, and the energy utilization efficiency of the entire cascade compression refrigeration system is improved.

The low temperature drying filter 254 is arranged between the condensation part and the low temperature throttling device 255, and plays the role of filtering impurities in the second refrigerant and preventing ice blockage.

The low temperature stage radiator 252 is arranged between the discharge port of the low temperature stage compressor 251 and the condensation part. The low-temperature radiator 252 enables the second refrigerant in the low-temperature refrigeration cycle to be pre-cooled before flowing to the condensing part, ensuring that the second refrigerant can be fully condensed when flowing through the condensing part.

The low temperature grade liquid storage bag 257 is arranged downstream of the low temperature grade evaporation pipe 256 and is located between the low temperature grade evaporation pipe 256 and the heat absorption return pipe section 258 . The low temperature stage liquid storage bag 257 can prevent the second refrigerant flowing to the suction port of the low temperature stage compressor 251 from carrying the liquid second refrigerant, and can also adjust the amount of the second refrigerant required by other components in the low temperature stage refrigeration cycle. When the low-temperature stage refrigeration cycle system is shut down, the second refrigerant at the low-temperature stage evaporating tube 256 is prevented from slowly migrating to the suction port of the low-temperature stage compressor 251 .

In this embodiment, in the low temperature stage refrigeration cycle, the second refrigerant can flow through the discharge port of the low temperature stage compressor 251, the low temperature stage radiator 252, the condenser, the low temperature stage drying filter 254, and the low temperature stage throttle in sequence. The device 255, the low-temperature stage evaporation tube 256, the low-temperature stage liquid storage bag 257, the second heat-absorbing return pipe section 258, the first heat-absorbing return pipe section 242, and the suction port of the low-temperature stage compressor 251 form a complete cycle.

Among them, after the second refrigerant flows through the low temperature radiator 252 for heat dissipation (corresponding to 3 points in FIG. 2 and FIG. 3 ), the temperature can be close to the ambient temperature but still a superheated gas, that is, the second refrigerant is flowing During passage through the low temperature grade heat sink 252, the degree of superheat may be reduced. The second refrigerant output from the condensing part is a high-pressure liquid second refrigerant (corresponding to 4 points in FIG. 2 and FIG. 3 ), and after passing through the low-temperature stage throttling device 255 , it becomes a low-temperature and low-pressure second refrigerant (corresponding to 4 points in FIG. 2 and FIG. 3 ). at point 5 in Figures 2 and 3). The second refrigerant output from the low-temperature stage evaporating tube 256 (corresponding to point 6 in FIG. 2 and FIG. 3 ) enters the second heat-absorbing return pipe section 258 and absorbs the second refrigerant flowing through the low-temperature stage throttling device 255 After heating the agent, the temperature can be increased but the superheat is lower (corresponding to point 7 in Figures 2 and 3). After the second refrigerant enters the first heat-absorbing return pipe section 242 and absorbs heat, the temperature can be increased to be close to the ambient temperature, and the degree of superheat is correspondingly increased.

The high temperature stage refrigeration cycle may further include: an electric switching valve 217, a plurality of cooling branches, a second cooling evaporator 222, an anti-dew pipe 215, and a high temperature liquid storage bag. Wherein, there may be one or more cooling branches. There may be multiple cooling branches in this embodiment, and they are arranged in parallel with each other.

The high temperature stage refrigeration cycle may further include: an electric switching valve 217, a plurality of cooling branches, a second cooling evaporator 222, an anti-dew pipe 215, and a high temperature liquid storage bag. Wherein, there may be one or more cooling branches. There may be multiple cooling branches in this embodiment.

The electric switching valve 217 has a plurality of valve ports, and the plurality of valve ports are respectively used to communicate with a cooling branch. A refrigerant flow path. The electric switching valve 217 is used to switch and control the flow direction of the first refrigerant, so that the first refrigerant flowing therethrough is controlled to flow to one or more cooling branches. The electric switching valve 217 may be disposed upstream of the plurality of cooling branches and downstream of the high temperature stage condenser 212 .

There are a plurality of cooling branches arranged in parallel with each other, and each cooling branch is provided with a branch throttling device 218 . Cooling branches can be two, three, four or five, or any other number. In this embodiment, there may be three cooling branches, including a first cooling branch, a second cooling branch, and a third cooling branch. The branch throttling device 218 may be a capillary tube or an expansion valve. Since the setting of the throttling device is well known to those skilled in the art, details are not described here.

The first cooling branch is provided with a first cooling evaporation tube 219 and a one-way valve 220 therein. Among them, the first cooling evaporation tube 219 is used to promote the first refrigerant flowing therethrough to absorb heat. The first cooling evaporation tube 219 and the low temperature evaporation tube 256 are used to supply cooling to the same storage compartment 111 . For example, the first cooling-supply evaporating tube 219 and the low-temperature-level evaporating tube 256 may be used to be disposed in the evaporator installation cavity corresponding to the cryogenic compartment, and used to supply cooling to the cryogenic compartment. The first cooling evaporating tube 219 and the low-temperature evaporating tube 256 pass through the same fin group. 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 to say, the double-tube evaporator has a first cooling-supplying evaporation tube 219 and a low-temperature-level evaporation tube 256, and there are two sets of evaporation tubes in total. The first cooling-supply evaporating tube 219 and the low-temperature-level evaporating tube 256 may be arranged adjacent to each other, or may be arranged against each other, or arranged around each other, but not limited thereto.

The first cooling evaporation tube 219 and the low temperature evaporation tube 256 are configured to be arranged in the same evaporator installation cavity corresponding to the same storage compartment 111 and used for supplying cooling to the same storage compartment 111, which can improve the performance of the cooling system. The cooling efficiency of the storage compartment 111 makes the storage compartment 111 cool down rapidly.

Using the first cooling evaporation tube 219 and the low-temperature stage evaporation tube 256 to form a double-tube evaporator not only helps to improve the refrigeration efficiency of the double-tube evaporator, but also facilitates the miniaturization of the structure of the double-tube evaporator and simplifies the structure of the double-tube evaporator. The overall structure of the refrigeration equipment 10 of the type compression refrigeration system reduces the manufacturing cost.

When the cascade compression refrigeration system starts to operate, the cooling process of the cryogenic compartment can be divided into two stages: the initial stage and the later stage. The initial stage may be the process in which the temperature of the cryogenic compartment is lowered from the ambient temperature to the first preset temperature, and the later stage may be the process in which the temperature of the cryogenic compartment is lowered from the first preset temperature to the second preset temperature , the first preset temperature is higher than the second preset temperature. The first preset temperature can be any value between -10°C and -28°C, for example, it can be -18°C, and the second preset temperature can be any value between -40°C and -80°C, for example, it can be - 55°C. The first cooling evaporation tube 219 may be used to supply cooling for the initial stage, and the low temperature stage evaporation tube 256 may be used to supply cooling for the later stage.

Usually, whether the evaporator provides cooling is determined by whether the refrigerant circulates in it. For example, it is possible to control whether the first refrigerant flows through the first cooling evaporation tube 219 by controlling the electric switching valve 217 (which will be described in detail below), so as to control whether the first cooling evaporation tube 219 supplies cooling. Whether the low temperature stage compressor 251 is turned on is used to control whether the second refrigerant flows through the low temperature stage evaporation tube 256, so as to control whether the low temperature stage evaporation tube 256 provides cooling.

In some optional embodiments, the first cooling evaporation tube 219 and the low temperature stage evaporation tube 256 may also be used to be arranged in the evaporator installation cavity corresponding to the temperature changing compartment, and used to supply cooling to the temperature changing compartment. The temperature-changing compartment can selectively control the first cooling evaporation tube 219 or the low temperature stage evaporation tube 256 to supply cooling alone, or control the first cooling evaporation tube 219 and the low temperature stage evaporation tube 256 to supply cooling together, so as to make the The variable temperature room can obtain different cooling effects to meet different cooling demands.

The one-way valve 220 is disposed downstream of the first cooling evaporating pipe 219 and is used to allow only the first refrigerant from the first cooling evaporating pipe 219 to flow out in one direction. That is, in the first cooling branch, the one-way valve 220 is only used to allow the first refrigerant from its upstream to pass in one direction, and the one-way valve 220 can prevent the reverse direction of the first refrigerant downstream of the one-way valve 220 pass.

When the low temperature stage compressor 251 operates, the temperature of the low temperature stage evaporator tube 256 is very low. Because the distance between the low-temperature stage evaporating tube 256 and the first cooling-supplying evaporating tube 219 is relatively short, the pipeline temperature of the first cooling-supplying evaporating tube 219 is relatively low, even significantly lower than the temperature of the first cooling-supplying evaporating tube 219, which is significantly lower than that in the high-temperature stage refrigeration cycle. The temperature of other cooling evaporators downstream of the first cooling evaporator tube 219 . A check valve 220 located downstream of the first cooling evaporation pipe 219 is provided in the first cooling branch, so as to prevent the first refrigerant in other cooling evaporators located downstream of the first cooling evaporation pipe 219 from passing from the first The discharge port of the cooling evaporation pipe 219 flows into the first cooling evaporation pipe 219, so that the reverse flow of the first refrigerant in the high temperature refrigeration cycle can be avoided, the effective flow of the first refrigerant is ensured, and the overall refrigeration is improved. efficiency.

A cooling evaporator or an evaporation tube for supplying cooling to the storage compartment 111 may not be provided in the second cooling branch.

A third cooling evaporator 221 may be arranged in the third cooling branch, and the third cooling evaporator 221 may be arranged in the evaporator installation cavity corresponding to the refrigerating compartment and used to supply the refrigerating compartment cold.

The second cooling evaporator 222 is disposed between the high temperature stage condenser 212 and the suction port of the high temperature stage compressor 211 , and is used to facilitate the passage of the first refrigerant from the plurality of cooling branches to the suction port of the high temperature stage compressor 211 . The second cooling evaporator 222 is also used to induce the first refrigerant flowing therethrough to absorb heat, so that the temperature of the storage compartment 111 where the second cooling evaporator 222 is located is lowered. The second cooling evaporator 222 may be arranged in an evaporator installation cavity corresponding to the freezing compartment, and used for supplying cooling to the freezing compartment.

The evaporation part 231 may be arranged between the high temperature stage condenser 212 and the second cooling evaporator 222 , and a plurality of cooling branches may be arranged between the high temperature stage condenser 212 and the evaporation part 231 . That is, a plurality of cooling branches may be located downstream of the high temperature stage condenser 212 and upstream of the evaporation part 231 , and the second cooling evaporator 222 may be located downstream of the evaporation part 231 and upstream of the suction port of the high temperature stage compressor 211 .

The first cooling evaporation tube 219 and the third refrigeration evaporator are arranged between the high temperature stage condenser 212 and the evaporation part 231, and the second refrigeration evaporator is arranged between the evaporation part 231 and the suction inlet of the high temperature stage compressor 211, Each evaporator or evaporating tube promotes the first refrigerant flowing through it to evaporate and absorb heat and provide cooling for the storage compartment 111, making full use of the cooling capacity generated in the high-temperature refrigeration cycle, improving the high-temperature refrigeration cycle Therefore, the energy utilization efficiency of the entire refrigeration equipment 10 is improved.

The anti-dew pipe 215 is arranged between the high temperature stage condenser 212 and the cooling branch, and is used to promote the heat release of the first refrigerant flowing therethrough. The anti-dew pipe 215 can be used to be arranged at the edge portion around the door body of the refrigerator. When the cascade compression refrigeration system is running, the first refrigerant releases heat when it flows through the anti-dew pipe 215, so that the anti-dew pipe 215 heats up and generates heat, thereby reducing or avoiding condensation on the edge of the refrigerator door, making the edge of the refrigerator door Keeping it dry can avoid problems such as poor sealing of the box body 110 due to rust at the edge of the door body.

The high temperature grade liquid storage bag may include a high temperature grade first liquid storage bag and a high temperature grade second liquid storage bag 223 . The high-temperature stage first liquid storage bag is arranged between the high-temperature stage condenser 212 and the anti-dew pipe 215, and is used to adjust other components in the high-temperature stage refrigeration cycle (for example, the high-temperature stage condenser 212, the evaporation part 231, or the The amount of first refrigerant required by the evaporating tube or evaporator for cooling. Because under different working conditions, the flow rate of the first refrigerant required by each component in the high temperature stage refrigeration cycle circuit may be different. The high temperature stage first liquid storage bag can controllably increase the liquid level when the flow rate of the first refrigerant required by other components in the high temperature stage refrigeration cycle decreases. The high temperature stage first liquid storage bag can also controllably lower the liquid level when the flow rate of the first refrigerant required by other components in the high temperature stage refrigeration cycle increases. The high temperature grade first liquid storage bag is a high pressure liquid storage bag. When the high temperature stage refrigeration cycle system operates stably, the first refrigerant entering the high temperature stage first liquid storage bag is usually in a saturated liquid state.

The high temperature stage second liquid storage bag 223 is arranged between the second cooling evaporator 222 and the suction port of the high temperature stage compressor 211 . The high temperature stage second liquid storage bag 223 can prevent the first refrigerant flowing to the suction port of the high temperature stage compressor 211 from carrying the liquid first refrigerant, and can also adjust the flow rate of the first refrigerant required by other components in the high temperature stage refrigeration cycle , it is also possible to prevent the first refrigerant at the second cooling evaporator 222 from slowly migrating to the suction port of the high temperature stage compressor 211 when the high temperature stage refrigeration cycle system is shut down.

The high-temperature-grade refrigeration cycle circuit may further include: a high-temperature-grade filter drier 216 disposed between the anti-dew pipe 215 and the electric switching valve 217 . The high-temperature drying filter 216 plays the role of filtering impurities in the first refrigerant and preventing ice blockage.

In this embodiment, in the high-temperature stage refrigeration cycle, the first refrigerant can flow through the discharge port of the high-temperature stage compressor 211, the high-temperature stage condenser 212, the high-temperature stage first liquid storage bag, the anti-dew pipe 215, and the high-temperature stage in sequence. Stage drier 216, electric switching valve 217, multiple cooling branches (including branch throttling device 218, first cooling evaporator, one-way valve 220, third cooling evaporator 221), evaporation part 231 , the second cooling evaporator 222, the high temperature stage second liquid storage bag 223, and the suction port of the high temperature stage compressor 211 to form a complete cycle.

In some other optional embodiments, the position of the evaporation part 231 can be changed. Multiple cooling branches can also be arranged between the high temperature stage condenser 212 and the second cooling evaporator 222, for example, the electric switching valve 217 and the cooling branch can be arranged between the filter drier and the second cooling evaporator 222, and the evaporation part 231 can be arranged in the second cooling branch.

4 is a schematic diagram of a cascade compression refrigeration system according to another embodiment of the present invention. In another optional embodiment, a heat release part 241 may be added in the high temperature stage refrigeration cycle. The high temperature stage refrigeration cycle may further include a heat release part 241, and the heat release part 241 may be located between the high temperature stage condenser 212 and the evaporation part 231, for example, may be arranged between the high temperature stage condenser 212 and a plurality of cooling branches . The first heat-absorbing and returning air pipe section 242 and the heat-releasing portion 241 may be abutted against each other or arranged in a sleeved connection with each other. The first heat-absorbing return pipe section 242 is used to promote the second refrigerant flowing therethrough to absorb the heat of the first refrigerant flowing through the heat releasing part 241, so that the second refrigerant in the low-temperature stage refrigeration cycle is flowing into the compressor. By raising the temperature before the suction port, the suction temperature of the low-temperature stage compressor 251 can be increased.

Since the temperature of the first refrigerant flowing from the high temperature stage condenser 212 is higher than the temperature of the second refrigerant between the low temperature stage evaporating tube 256 and the suction port of the low temperature stage compressor 251 , the second refrigerant flowing through the heat absorption part can absorb The heat of the first refrigerant flowing through the heat release part 241 is heated up, and the heat in the high temperature stage refrigeration cycle is fully utilized, thereby improving the energy utilization efficiency of the high temperature stage refrigeration cycle.

In some optional embodiments, during operation of the cascade compression refrigeration system, only the heat release part 241 may be used to provide heat for the first heat-absorbing return pipe section 242, or the heat release part 241 and the auxiliary heating device 243 may be used at the same time. Provide heat to the first heat-absorbing return pipe section 242 to increase the suction temperature of the low-temperature stage compressor 251 .

As for the throttling device, Figures 2 and 4 only illustrate capillary tubes, but it should not be considered that the throttling device in the above embodiment is limited to capillary tubes.

The cooling fan 280 is used to promote the formation of an air flow that flows through the high temperature stage condenser 212 and then flows through the low temperature stage radiator 252, or is used to promote the formation of an air flow that flows through the low temperature stage radiator 252 and then flows through the high temperature stage condenser 212 air flow, or is used to promote the formation of air flow through the low temperature stage radiator 252 and the high temperature stage condenser 212, respectively. The low temperature radiator 252 and the high temperature condenser 212 may be disposed adjacent to each other, and the cooling fan 280 may be disposed on one side of the low temperature radiator 252 and the high temperature condenser 212 . The cooling fan 280 can increase the wind speed and air volume flowing through the low temperature radiator 252 and the high temperature condenser 212, so as to promote the rapid heat dissipation of the low temperature radiator 252 and the high temperature radiator, enhance the heat dissipation effect, and make the cascade compression refrigeration system And the refrigeration device 10 having the same can continue to work within the normal temperature range.

The temperature of the low temperature stage radiator 252 is lower than the temperature of the high temperature stage condenser 212 . The low temperature stage radiator 252 and the high temperature stage condenser 212 are arranged adjacent to each other, and the same cooling fan 280 can be used to promote the formation of an air flow that first flows through the low temperature stage radiator 252 and then flows through the high temperature stage condenser 212, which not only ensures the low temperature stage heat dissipation The cooling effect of the condenser 252 and the high-temperature stage condenser 212 is improved, and the number of the cooling fans 280 is simplified, which is beneficial to realize the miniaturization of the structure.

There can be multiple air blowers 290 , which are respectively configured to correspond to one evaporator installation cavity, and corresponding to each storage compartment 111 , and used to blow cold air for each storage compartment 111 . The plurality of air supply fans may include a first air supply fan, which may be arranged corresponding to the evaporator installation cavity where the first cooling evaporation tube 219 and the low temperature stage evaporation tube 256 are located, for example, may be arranged in the first cooling evaporation tube 219 and One side of the low temperature evaporating pipe 256 is used to guide the airflow flowing through the first cooling supply evaporating pipe 219 and the low temperature evaporating pipe 256 to the storage compartment 111 .

In some other optional embodiments, the cascade compression refrigeration system may further include a heat exchange device arranged in the low temperature stage refrigeration cycle circuit. A heat exchange device includes: a heat release part and a heat absorption part. The heat radiating element is disposed between the condensation part 232 and the low-temperature stage throttling device 255 . The heat absorbing member is arranged between the low temperature stage evaporating tube 256 and the suction port of the low temperature stage compressor 251, and the heat absorbing member is configured to cause the second refrigerant flowing therethrough 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 condensing part 232 can continue to be condensed on the heat releasing member, so that the second refrigerant flowing out of the heat releasing member can be realized Fully condensing, it also makes the second refrigerant flowing out of the low-temperature stage evaporating tube 256 continue to evaporate in the heat-absorbing element, which reduces the compression ratio of the low-temperature stage compressor 251 to a certain extent, and can also reduce or avoid the occurrence of excessively low suction temperature. reduce the loss of cooling capacity, improve the cooling efficiency, and avoid condensation or frost formation near the suction port of the low-temperature stage compressor 251.

The cascade compression refrigeration system of the present embodiment and the refrigeration equipment 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 condensing evaporator. The condensing evaporator includes an evaporating part 231 arranged in the high temperature stage refrigeration cycle circuit and a condensing part 231 arranged in the low temperature stage refrigeration cycle circuit. The low-temperature stage refrigeration cycle includes a first heat-absorbing return pipe section 242 and an auxiliary heating device 243, and the auxiliary heating device 243 is used to heat the second refrigerant in the first heat-absorbing return pipe section 242, so that the low-temperature stage refrigeration cycle loop is The temperature of the second refrigerant is heated before flowing into the suction port of the compressor, so that the suction temperature of the low-temperature stage compressor 251 can be increased, the cooling capacity loss caused by the low suction temperature can be reduced or avoided, the cooling efficiency can be improved, and the cooling efficiency can be reduced or avoided. Condensation or frost has occurred around the suction port of the low temperature stage compressor 251. Compared with the scheme of arranging thermal insulation cotton on the heat-absorbing and return-air pipe section, the consistency of product performance during mass production of small household refrigeration equipment is improved.

By now, those skilled in the art will recognize that although various exemplary embodiments of the present invention have been shown and described in detail herein, without departing from the spirit and scope of the present invention, Numerous other variations or modifications consistent with the principles of the present invention are directly identified or derived from the disclosure of the present invention. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims (10)

1. A cascade compression refrigeration system, comprising:

the high-temperature stage refrigeration cycle loop is used for circulating a first refrigerant;

the low-temperature stage refrigeration circulation loop is used for circulating a second refrigerant and is internally provided with a low-temperature stage compressor and a low-temperature stage evaporation pipe;

the low-temperature-stage refrigeration cycle further includes:

the first heat absorption air return pipe section is arranged between the low-temperature-stage evaporation pipe and the low-temperature-stage compressor suction port;

and the auxiliary heating device is used for heating the second refrigerant in the first heat absorption return gas pipe section.

2. The cascade compression refrigeration system of claim 1, wherein the cascade compression refrigeration system comprises

The auxiliary heating device is an electric heating device and is arranged on one side of the first heat absorption air return pipe section or wound on the first heat absorption air return pipe section.

3. The cascade compression refrigeration system of claim 1, further comprising:

a condensing evaporator having an evaporation portion located in the high-temperature stage refrigeration cycle circuit and a condensation portion located in the low-temperature stage refrigeration cycle circuit; the evaporation portion for causing the first refrigerant flowing therethrough to absorb heat of the second refrigerant flowing through the condensation portion;

the low-temperature-stage refrigeration cycle further includes:

the second heat absorption air return pipe section is arranged between the low-temperature-stage evaporation pipe and the first heat absorption air return pipe section;

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

the second heat absorbing return leg is configured to cause the second refrigerant flowing therethrough to absorb heat from the second refrigerant flowing through the low temperature stage throttling device.

4. The cascade compression refrigeration system of claim 3, wherein the high temperature stage refrigeration cycle comprises:

a high temperature stage compressor;

a high-temperature-stage condenser disposed between the high-temperature-stage compressor discharge port and the evaporation unit;

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

a first cooling branch provided with a first cooling evaporation pipe therein, the first cooling evaporation pipe being used for promoting the first refrigerant flowing through the first cooling branch to absorb heat;

the first cooling evaporation pipe and the low-temperature-level evaporation pipe are used for cooling the same storage compartment in the refrigeration equipment.

5. The cascade compression refrigeration system of claim 4, wherein the cascade compression refrigeration system comprises

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

6. The cascade compression refrigeration system of claim 4, wherein the cascade compression refrigeration system comprises

The first cooling branch is internally provided with a one-way valve, and the one-way valve is arranged at the downstream of the first cooling evaporation pipe and is used for only allowing the first refrigerant from the first cooling evaporation pipe to flow in one direction.

7. The cascade compression refrigeration system of claim 4, wherein the high temperature stage refrigeration cycle further comprises:

a second refrigeration evaporator disposed between the high temperature stage condenser and the high temperature stage compressor suction inlet for forcing the first refrigerant from the plurality of refrigeration branches to the high temperature stage compressor suction inlet;

the plurality of cooling branches are arranged between the high-temperature-stage condenser and the second cooling evaporator.

8. The cascade compression refrigeration system of claim 4, wherein the high temperature stage refrigeration cycle further comprises:

and an electric switching valve having a plurality of valve ports for communicating with one of the cooling branches, respectively, for adjusting a flow path of the first refrigerant therethrough by controllably opening or closing the valve ports.

9. The cascade compression refrigeration system of claim 4, wherein the high temperature stage refrigeration cycle further comprises:

and the dew prevention 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 prevention pipe to release heat.

10. A refrigeration apparatus, comprising:

a box body;

the cascade compression refrigeration system according to any one of claims 1 to 9 disposed within the tank.

Images