CN112880218A

CN112880218A - Refrigerator defrosting system, refrigerator and refrigerator defrosting method

Info

Publication number: CN112880218A
Application number: CN202110325192.3A
Authority: CN
Inventors: 刘绍文; 卢起彪; 朱文琪; 邓涵; 孟贺; 牛二帅
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2021-03-26
Filing date: 2021-03-26
Publication date: 2021-06-01

Abstract

The invention discloses a refrigerator defrosting system, a refrigerator and a refrigerator defrosting method, relates to the field of refrigerator defrosting, and aims to improve the defrosting effect of the refrigerator. The defrosting system of the refrigerator comprises a compressor, a condenser, a first heat exchanger, a second heat exchanger, a first auxiliary branch and a second auxiliary branch. The compressor is configured to compress a refrigerant. The fluid inlet of the condenser is in communication with the fluid outlet of the compressor. A first branch and a second branch are arranged between the fluid inlet of the first heat exchanger and the fluid outlet of the condenser in parallel, and the fluid outlet of the first heat exchanger is communicated with the fluid inlet of the compressor. A third branch and a fourth branch are arranged between the fluid inlet of the second heat exchanger and the fluid outlet of the condenser in parallel, the first branch and the third branch are not provided with throttling elements, and the second branch and the fourth branch are respectively provided with throttling elements; the fluid outlet of the second heat exchanger is in communication with the fluid inlet of the compressor. The technical scheme ensures that the frost layer is integrally peeled off and the defrosting efficiency is high.

Description

Refrigerator defrosting system, refrigerator and refrigerator defrosting method

Technical Field

The invention relates to the field of refrigerator defrosting, in particular to a refrigerator defrosting system, a refrigerator and a refrigerator defrosting method.

Background

Refrigerators are used to freeze and refrigerate food. In the related art, a refrigerator includes a freezing chamber, a refrigerating chamber, and an evaporating chamber. The evaporation chamber is located at the rear side of the refrigerator. The evaporation chamber is used for generating cold air. The evaporating chamber is communicated with the freezing chamber and the refrigerating chamber through respective air ducts. The evaporator is disposed in the evaporation chamber. In the related art, a defrosting mode of a refrigerator is electric heating defrosting, an electric heating pipe is arranged below an evaporator, and natural convection is formed by heating air and heat radiation of the electric heating pipe is used for defrosting the evaporator.

The inventor finds that at least the following problems exist in the prior art: the defrosting is carried out by utilizing an electric heating mode, the defrosting efficiency is low, the defrosting time is long, the defrosting power consumption is high, the temperature rise of a freezing chamber is high, and the normal use of the refrigerator is influenced.

Disclosure of Invention

The invention provides a refrigerator defrosting system, a refrigerator and a refrigerator defrosting method, which are used for improving the defrosting effect of the refrigerator.

The embodiment of the invention provides a defrosting system of a refrigerator, which comprises:

a compressor configured to compress a refrigerant;

a condenser having a fluid inlet in communication with a fluid outlet of the compressor;

a first branch and a second branch are arranged between a fluid inlet of the first heat exchanger and a fluid outlet of the condenser in parallel, the first branch is not provided with a throttling element, and the second branch is provided with a first throttling element; a fluid outlet of the first heat exchanger is communicated with a fluid inlet of the compressor;

a third branch and a fourth branch are arranged between a fluid inlet of the second heat exchanger and a fluid outlet of the condenser in parallel, the third branch is not provided with a throttling element, and the fourth branch is provided with a second throttling element; the fluid outlet of the second heat exchanger is communicated with the fluid inlet of the compressor;

one end of the first auxiliary branch is communicated with the inflow end of the fourth branch, the other end of the first auxiliary branch is communicated with the outflow port of the first heat exchanger, and the first auxiliary branch is provided with a first stop valve; and

one end of the second auxiliary branch is communicated with the inflow end of the second branch, the other end of the second auxiliary branch is communicated with the outflow port of the second heat exchanger, and the second auxiliary branch is provided with a second stop valve.

In some embodiments, a third stop valve is disposed between the fluid outlet of the first heat exchanger and the other end of the first auxiliary branch and the fluid inlet of the compressor.

In some embodiments, a fourth stop valve is commonly disposed between the fluid outlet of the second heat exchanger and the other end of the second auxiliary branch and the fluid inlet of the compressor.

In some embodiments, the refrigerator defrost system further comprises:

and the electromagnetic valve is provided with an inflow port and four outflow ports, the inflow port of the electromagnetic valve is communicated with the fluid outlet of the condenser, and the four outflow ports are communicated with the first branch, the second branch, the third branch and the fourth branch in a one-to-one correspondence manner.

In some embodiments, a third stop valve is commonly arranged between the fluid outlet of the first heat exchanger and the other end of the first auxiliary branch and the fluid inlet of the compressor;

a fourth stop valve is arranged between the fluid outlet of the second heat exchanger and the other end of the second auxiliary branch and the fluid inlet of the compressor;

the defrosting system of the refrigerator further comprises a solenoid valve, wherein the solenoid valve is provided with an inflow port and four outflow ports, the inflow port of the solenoid valve is communicated with the fluid outlet of the condenser, and the four outflow ports are communicated with the first branch, the second branch, the third branch and the fourth branch in a one-to-one correspondence manner;

wherein the refrigerator defrost system is configured to adopt a branch conduction mode of one of the following:

in a mode to defrost the first heat exchanger: a first flow outlet of the electromagnetic valve is opened, the first stop valve and the fourth stop valve are both opened, the third stop valve and the second stop valve are both closed, and the first branch and the fourth branch are communicated through the first auxiliary branch, so that a refrigerant sequentially flows through the first branch, the first auxiliary branch and the fourth branch; or a fourth outflow port of the electromagnetic valve is opened, the first stop valve, the third stop valve and the second stop valve are all closed, and the fourth stop valve is opened, so that the refrigerant only flows through the fourth branch; or

In a mode to defrost the second heat exchanger: a third flow outlet of the electromagnetic valve is opened, the second stop valve and the third stop valve are opened, the fourth stop valve and the first stop valve are both closed, and the third branch and the second branch are communicated through the second auxiliary branch, so that a refrigerant sequentially flows through the third branch, the second auxiliary branch and the second branch; or, a second outlet of the electromagnetic valve is opened, the first stop valve, the second stop valve and the fourth stop valve are all closed, and the third stop valve is opened, so that the refrigerant only flows through the second branch.

In some embodiments, the first throttling element comprises a capillary tube and/or an electronic expansion valve; and/or the second throttling element comprises a capillary tube and/or an electronic expansion valve.

The embodiment of the invention also provides a refrigerator comprising the defrosting system of the refrigerator provided by any technical scheme of the invention.

The embodiment of the invention also provides a defrosting method of a refrigerator, which is implemented by adopting the defrosting system of the refrigerator provided by any technical scheme of the invention, and the method comprises the following steps:

judging whether the first heat exchanger and the second heat exchanger of the refrigerator meet defrosting conditions or not;

the embodiment of the invention provides a defrosting method of a refrigerator, which is implemented by adopting the defrosting system of the refrigerator provided by any technical scheme of the invention, and the method comprises the following steps:

if the first heat exchanger meets the defrosting condition, the first heat exchanger and the condenser are connected in series to increase the temperature of a frost layer outside the first heat exchanger and reduce the humidity of the environment where the first heat exchanger is located, so that the first heat exchanger is defrosted; if the second heat exchanger meets the defrosting condition, the condenser and the second heat exchanger are connected in series to increase the temperature of a frost layer on the outer side of the second heat exchanger and reduce the humidity of the environment where the second heat exchanger is located, so that the second heat exchanger is defrosted.

In some embodiments, if the first heat exchanger meets a defrosting condition, the defrosting of the first heat exchanger is implemented by connecting the first heat exchanger and the condenser in series to increase the temperature of a frost layer outside the first heat exchanger and reduce the humidity of the environment in which the first heat exchanger is located, specifically including the following steps:

if the first heat exchanger meets the defrosting condition, enabling a first branch at the upstream of the first heat exchanger to be conducted, enabling the fourth branch to be conducted, disconnecting the second branch and the third branch, and enabling the first auxiliary branch to be conducted so as to increase the temperature of a frost layer on the first heat exchanger;

judging whether the temperature of the heated frost layer on the first heat exchanger reaches a set value or not;

and if the frost layer temperature on the first heat exchanger reaches a set value, enabling a fourth branch at the upstream of the second heat exchanger to be conducted, disconnecting the first branch, the second branch and the third branch, and disconnecting the first auxiliary branch and the second auxiliary branch so as to reduce the humidity of the environment where the first heat exchanger is located.

In some embodiments, if the second heat exchanger satisfies a defrosting condition, the defrosting of the second heat exchanger is implemented by connecting the condenser and the second heat exchanger in series to increase the temperature of a frost layer outside the second heat exchanger and reduce the humidity of the environment in which the second heat exchanger is located, specifically including the following steps:

if the second heat exchanger meets the defrosting condition, enabling a third branch at the upstream of the second heat exchanger to be conducted, conducting the second branch, disconnecting the first branch and the fourth branch, and conducting the second auxiliary branch to increase the frost layer temperature on the second heat exchanger;

judging whether the temperature of the heated frost layer of the second heat exchanger reaches a set value or not;

and if the frost layer temperature on the second heat exchanger reaches a set value, enabling a second branch at the upstream of the first heat exchanger to be conducted, disconnecting the first branch, the third branch and the fourth branch, and disconnecting the first auxiliary branch and the second auxiliary branch so as to reduce the humidity of the environment where the second heat exchanger is located.

In some embodiments, the refrigerator defrosting method further includes the steps of:

if the temperature of the refrigerant outlet of the first heat exchanger is higher than a set value, the defrosting step of the first heat exchanger is quitted; and if the temperature of the refrigerant outlet of the second heat exchanger is higher than a set value, the defrosting step of the second heat exchanger is quitted.

In some embodiments, before the determining whether the first heat exchanger and the second heat exchanger of the refrigerator satisfy the defrosting condition, the method further includes the steps of:

at least one of the first heat exchanger and the second heat exchanger is used as an evaporator to realize refrigeration of the refrigerator.

The refrigerator defrosting system provided by the technical scheme is also provided with the first heat exchanger and the second heat exchanger outside the condenser. And in the normal refrigeration mode, refrigerating the refrigerator by at least one of the first heat exchanger and the second heat exchanger. Under the defrosting mode, through the operating condition of control first heat exchanger and second heat exchanger, realize utilizing the principle of sublimating to defrosting in arbitrary one in first heat exchanger and the second heat exchanger. The frost layer on the surface of the heat exchanger to be defrosted forms a certain absolute humidity difference with the ambient air, the temperature of the frost layer reaches a certain condition, the frost layer can be sublimated, and when the temperature of the frost layer decreases gradually from the root to the outside, the frost layer can be sublimated from the root and is peeled off integrally. The defrosting time is shortened and the defrosting efficiency is improved by adopting the defrosting system of the refrigerator.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1 is a schematic diagram of a refrigerator defrost system according to some embodiments of the present invention;

FIG. 2 is a flow chart illustrating a defrosting method for a refrigerator according to other embodiments of the present invention;

FIG. 3 is a detailed schematic view of the defrosting step of the first heat exchanger of FIG. 2;

fig. 4 is a detailed process diagram of defrosting the second heat exchanger in fig. 2.

Detailed Description

The technical solution provided by the present invention is explained in more detail with reference to fig. 1 to 4.

Referring to fig. 1, an embodiment of the present invention provides a defrosting system for a refrigerator, including a compressor 1, a condenser 2, a first heat exchanger 3, a second heat exchanger 4, a first auxiliary branch 14, and a second auxiliary branch 15. The compressor 1 is configured to compress a refrigerant. The fluid inlet of the condenser 2 communicates with the fluid outlet of the compressor 1. A first branch 5 and a second branch 6 are arranged between the fluid inlet of the first heat exchanger 3 and the fluid outlet of the condenser 2 in parallel, the first branch 5 is not provided with a throttling element, and the second branch 6 is provided with a first throttling element 7; the fluid outlet of the first heat exchanger 3 communicates with the fluid inlet of the compressor 1. A third branch 8 and a fourth branch 9 are arranged between the fluid inlet of the second heat exchanger 4 and the fluid outlet of the condenser 2 in parallel, the third branch 8 is not provided with a throttling element, and the fourth branch 9 is provided with a second throttling element 10; the fluid outlet of the second heat exchanger 4 communicates with the fluid inlet of the compressor 1.

One end of the first auxiliary branch 14 communicates with the inflow end of the fourth branch 9, the other end of the first auxiliary branch 14 communicates with the outflow port of the first heat exchanger 3, and the first auxiliary branch 14 is provided with a first shut-off valve 16. One end of the second auxiliary branch 15 is communicated with the inflow end of the second branch 6, the other end of the second auxiliary branch 15 is communicated with the outflow port of the second heat exchanger 4, and the second auxiliary branch 15 is provided with a second stop valve 17.

The compressor 1 may have an existing structure, and the compressor 1 is used to compress a refrigerant and change the form, temperature, and pressure of the refrigerant.

The condenser 2 may also adopt an existing structure, and the condenser 2 receives the high-temperature and high-pressure gaseous refrigerant output by the compressor 1.

The refrigerator includes three chambers of a freezing chamber, a refrigerating chamber and an evaporating chamber. The first heat exchanger 3 and the second heat exchanger 4 are both installed in the evaporation chamber. The first heat exchanger 3 and the second heat exchanger 4 are arranged in two branches. Upstream of the first heat exchanger 3 are a first branch 5 and a second branch 6. The first branch 5 and the second branch 6 may either be conducting or both non-conducting. The first branch 5 is not provided with a throttling element, if the refrigerant output by the condenser 2 enters the first heat exchanger 3 through the first branch 5, the first heat exchanger 3 has the same function as the condenser 2 at the moment, and the refrigerant is also subjected to condensation heat exchange in the first heat exchanger 3. If the refrigerant output from the condenser 2 enters the first heat exchanger 3 via the second branch 6, the first heat exchanger 3 functions as an evaporator since the second branch 6 is provided with the first throttling element 7.

Upstream of the second heat exchanger 4 are a third branch 8 and a fourth branch 9. The third branch 8 and the fourth branch 9 may be either conductive or both non-conductive. The third branch 8 is not provided with a throttling element, if the refrigerant output by the condenser 2 enters the second heat exchanger 4 through the third branch 8, the second heat exchanger 4 has the same function as the condenser 2 at the moment, and the refrigerant is also subjected to condensation heat exchange in the second heat exchanger 4. If the refrigerant output from the condenser 2 enters the second heat exchanger 4 via the fourth branch 9, the second heat exchanger 4 functions as an evaporator since the fourth branch 9 is provided with the second throttling element 10.

The defrosting system of the refrigerator has two working states of refrigeration and defrosting.

In the normal refrigeration cycle, both the first heat exchanger 3 and the second heat exchanger 4 may be used as evaporators, or alternatively may be used as evaporators. When the refrigerating requirement of the refrigerator is large, the first heat exchanger 3 and the second heat exchanger 4 are used simultaneously. When the refrigerating requirement of the refrigerator is small, the first heat exchanger 3 and the second heat exchanger 4 are alternatively used.

Taking as an example that the first heat exchanger 3 and the second heat exchanger 4 are used as evaporators at the same time. The refrigerant output from the condenser 2 is divided into two branches, one of which enters the first heat exchanger 3 through the second branch 6, and the other of which enters the second heat exchanger 4 through the fourth branch 9. Then, the refrigerant output through the first heat exchanger 3 and the second heat exchanger 4 flows back to the compressor 1.

Taking the example where the first heat exchanger 3 and the second heat exchanger 4 are used alternatively as evaporators, the other may not be used. Taking the first heat exchanger 3 in the use state as an example, the branch in which the second heat exchanger 4 is located is disconnected. All the refrigerant output from the condenser 2 enters the first heat exchanger 3 through the second branch 6, and the refrigerant output from the first heat exchanger 3 flows back to the compressor 1.

Referring to fig. 1, in some embodiments, a third shut-off valve 11 is provided in common between the fluid outlet of the first heat exchanger 3 and the other end of the first auxiliary branch 14 and the fluid inlet of the compressor 1. The third stop valve 11 allows the refrigerant to flow from the first heat exchanger 3 to the compressor 1.

In some embodiments, a fourth stop valve 12 is commonly disposed between the fluid outlet of the second heat exchanger 4 and the other end of the second auxiliary branch 15 and the fluid inlet of the compressor 1. The fourth shutoff valve 12 allows the refrigerant to flow from the second heat exchanger 4 to the compressor 1 in one direction without flowing in a reverse direction.

In some embodiments, the refrigerator defrosting system further includes a solenoid valve 13, the solenoid valve 13 having an inflow port and four outflow ports, the inflow port of the solenoid valve 13 being communicated with the fluid outlet of the condenser 2, and the four outflow ports being communicated with the first branch 5, the second branch 6, the third branch 8, and the fourth branch 9 in one-to-one correspondence. The four outlet ports of the solenoid valve 13 are respectively an outlet port a, an outlet port b, an outlet port c, and an outlet port d. The outlet a communicates with the first branch passage 5. The outflow opening b communicates correspondingly with the second branch 6. The outflow opening c communicates correspondingly with the third branch 8. The outflow port d communicates correspondingly with the fourth branch 9.

The electromagnetic valve 13 is arranged, and on-off control of the first branch 5, the second branch 6, the third branch 8 and the fourth branch 9 can be realized by controlling the valve position of the electromagnetic valve 13. The term "pass" means that the refrigerant in the branch can flow from the upstream of the branch to the downstream through the branch; by "off" it is meant that the refrigerant in the branch cannot flow from upstream of the branch through the branch to downstream.

In some embodiments, the first throttling element 7 comprises a capillary tube or an electronic expansion valve; and/or the second restriction element 10 comprises a capillary tube or an electronic expansion valve. The control of the throttling effect can be realized by adjusting the opening degree of the electronic expansion valve.

Referring to fig. 1, the state control of each branch is described below. The defrosting system of the refrigerator is configured to adopt a branch conduction mode of one of the following modes:

the first method comprises the following steps: the first branch 5 and the fourth branch 9 are both switched on, and the second branch 6 and the third branch 8 are both switched off, the first auxiliary branch 14 being switched on, the second auxiliary branch 15 being switched off. In this manner, the first heat exchanger 3 and the condenser 2 are connected in series and both function to condense the refrigerant. The second heat exchanger 4 now functions as an evaporator. This condition is used for the first step of defrosting the first heat exchanger 3. Specific methods for defrosting the first heat exchanger 3 are described later. The first branch circuit conduction state is realized by adopting the following valve positions: the first outlet of the solenoid valve 13 is opened, the first stop valve 16 and the fourth stop valve 12 are both opened, the third stop valve 11 and the second stop valve 17 are both closed, and the first branch 5 and the fourth branch 9 are communicated through the first auxiliary branch 14, so that the refrigerant sequentially flows through the first branch 5, the first auxiliary branch 14 and the fourth branch 9.

And the second method comprises the following steps: the fourth branch 9 is on and the first, second and

third branches

5, 6, 8 are off, as are the first and second

auxiliary branches

14, 15. The fourth cut-off valve 12 is on and the third cut-off valve 11 is off. In this way, the second heat exchanger 4 is operated and the first heat exchanger 3 is not operated. The refrigerant flows to the condenser 2 through the compressor 1, then flows to the second heat exchanger 4 through the second throttling element 10 on the fourth branch 9, and finally flows back to the compressor 1 through the fourth stop valve 12. This condition is used for the second step of defrosting the first heat exchanger 3. Specific methods for defrosting the first heat exchanger 3 are described later. The second branch conduction state is realized by adopting the following valve positions: the fourth outlet port d of the solenoid valve 13 is opened, the first, third and

second cutoff valves

16, 11 and 17 are all closed, and the fourth cutoff valve 12 is opened, so that the refrigerant flows only through the fourth branch 9.

And the third is that: the third branch 8 and the second branch 6 are conducting, and the first branch 5 and the fourth branch 9 are both off, and the second auxiliary branch 15 is conducting. The third cut valve 11 is on and the fourth cut valve 12 is off. In this case, the second heat exchanger 4 and the condenser 2 are connected in series and both function to condense the refrigerant. The first heat exchanger 3 serves as an evaporator. The flow direction of the whole refrigerant is as follows: after exiting the compressor 1, it flows towards the condenser 2, through the third branch 8 towards the second heat exchanger 4, through the second auxiliary branch 15 towards the second branch 6, through the first throttling element 7 on the second branch 6 towards the first heat exchanger 3, and then through the third stop valve 11 back towards the compressor 1. This condition is used for the first step of defrosting the second heat exchanger 4. Specific methods for defrosting the second heat exchanger 4 are described later. The third branch conduction state is realized by adopting the following valve positions: the third outlet c of the solenoid valve 13 is opened, the second stop valve 17 and the third stop valve 11 are opened, the fourth stop valve 12 and the first stop valve 16 are both closed, and the third branch passage 8 and the second branch passage 6 are communicated through the second auxiliary branch passage 15, so that the refrigerant sequentially flows through the third branch passage 8, the second auxiliary branch passage 15 and the second branch passage 6.

The fourth method is as follows: the second branch 6 is on and the first, third and

fourth branches

5, 8, 9 are off, as are the first and second

auxiliary branches

14, 15. The third cut valve 11 is on and the fourth cut valve 12 is off. At this time, the second heat exchanger 4 does not operate, and the first heat exchanger 3 operates and functions as an evaporator. This condition is used for the second step of defrosting the second heat exchanger 4. Specific methods for defrosting the second heat exchanger 4 are described later. The third branch conduction state is realized by adopting the following valve positions: the second outlet b of the solenoid valve 13 is opened, the first, second and

fourth stop valves

16, 17 and 12 are all closed, and the third stop valve 11 is opened so that the refrigerant flows only through the second bypass 6.

The embodiment of the invention provides a refrigerator, which comprises a defrosting system of the refrigerator provided by any technical scheme of the invention.

Referring to fig. 2, an embodiment of the present invention provides a defrosting method for a refrigerator, which is implemented by using a defrosting system for a refrigerator provided by any technical solution of the present invention, and the method includes the following steps:

and S100, judging whether the first heat exchanger 3 and the second heat exchanger 4 of the refrigerator meet defrosting conditions or not.

The first heat exchanger 3 and the second heat exchanger 4 each satisfy the condition of defrosting, and do not defrost at the same time. The defrosting is started when the defrosting condition is met. The defrosting condition may be set as an operation time of the compressor 1 of the refrigerator, for example, after the compressor 1 of the refrigerator is continuously allowed for 10 to 12 hours, one of the first heat exchanger 3 and the second heat exchanger 4 enters a defrosting process, and after the previous heat exchanger finishes defrosting, the next heat exchanger is defrosted. Of course, other conditions may be adopted as the judgment condition for defrosting, such as the temperature of the compartment in which the first heat exchanger 3 and the second heat exchanger 4 are located, and the respective temperatures of the first heat exchanger 3 and the second heat exchanger 4.

Before the above-mentioned step S100, the refrigerator performs a normal cooling operation, i.e., at least one of the first heat exchanger 3 and the second heat exchanger 4 is used as an evaporator, to cool the refrigerating chamber and the freezing chamber of the refrigerator.

Step S200, if the first heat exchanger 3 meets the defrosting condition, the first heat exchanger 3 and the condenser 2 are connected in series to increase the temperature of a frost layer outside the first heat exchanger 3, and the humidity of the environment where the first heat exchanger 3 is located is reduced to provide an absolute humidity difference required by sublimation of the root of the frost layer, so that the first heat exchanger 3 is defrosted. If the second heat exchanger 4 meets the defrosting condition, the second heat exchanger 4 is defrosted by connecting the condenser 2 and the second heat exchanger 4 in series to increase the frost layer temperature of the second heat exchanger 4 and reduce the humidity of the environment where the second heat exchanger 4 is located.

Referring to fig. 3, in some embodiments, if a defrosting of the first heat exchanger 3 is required, the step S200 specifically includes the following steps:

step S211, if the first heat exchanger 3 meets the defrosting condition, the first branch 5 at the upstream of the first heat exchanger 3 is turned on, the fourth branch 9 is also turned on, the second branch 6 and the third branch 8 are both turned off, the first auxiliary branch 14 is turned on, and the second auxiliary branch 15 is turned off, so as to increase the frost layer temperature outside the first heat exchanger 3.

Defrosting of the first heat exchanger 3 comprises two steps: the first step is to warm the frost layer outside the first heat exchanger 3 by connecting the first heat exchanger 3 and the condenser 2 in series; the second step is to change the humidity of the environment where the first heat exchanger 3 is located by making the second heat exchanger 4 function as an evaporator, and the temperature condition and the humidity condition required by sublimation and defrosting are realized through the two steps, so that defrosting can be smoothly realized.

In a first step, the first branch 5 and the fourth branch 9 are both in the on state and the second branch 6 and the third branch 8 are both in the off state. The first cut-off valve 16 is opened and the second cut-off valve 17 is opened. The third stop valve 11 is opened and the fourth stop valve 12 is opened.

After the first branch 5 is conducted, the refrigerant output by the compressor 1 directly enters the first heat exchanger 3 through the first branch 5, and at this time, the refrigerant is also condensed in the first heat exchanger 3. The refrigerant carries out sensible heat exchange in the first heat exchanger 3, and carries out sensible heat heating on the frost layer outside the first heat exchanger 3. The temperature of the frost layer is higher at the side close to the pipe fins and lower at the side far away from the frost layer, and the temperature difference of the frost layer formed by the whole frost layer is gradually reduced from the root to the outside. The refrigerant then continues through the first shut-off valve 16 to the fourth branch 9. Since the fourth branch 9 is provided with the second throttling element 10, the refrigerant is throttled. Then, the refrigerant continues to flow to the second heat exchanger 4. At this time, the second heat exchanger 4 functions as an evaporator to reduce the ambient humidity by evaporation, which is to change the humidity of the frost layer outside the first heat exchanger 3. The changed ambient humidity in this step is not necessarily sufficient, so the next step S212 may be continued.

Step S212 determines whether the temperature of the heated frost layer on the first heat exchanger 3 reaches a set value.

The temperature of the frost layer may specifically be the root temperature of the frost layer, i.e. the temperature of the lowermost layer of the frost layer. The set value is, for example, from-10 ℃ to-5 ℃. When the temperature of the frost layer at the root of the defrosting evaporator is higher than the set value, it indicates that the temperature condition required for defrosting is met, and at this time, the frost layer is not heated any more, but the humidity of the ambient temperature where the frost layer is located, that is, the humidity of the environment where the first heat exchanger 3 is located is changed. If the temperature of the frost layer does not reach the set temperature, step S211 is continued until the temperature of the frost layer satisfies the set value.

Step S213, if the frost layer temperature outside the first heat exchanger 3 reaches the set value, the fourth branch 9 upstream of the second heat exchanger 4 is turned on, and the first branch 5, the second branch 6, and the third branch 8 are all turned off, so as to reduce the humidity of the environment where the first heat exchanger 3 is located. In this state, the first auxiliary branch 14 and the second auxiliary branch 15 are also in the open state.

The fourth branch 9 is conducting and the second heat exchanger 4 now functions as an evaporator. The second heat exchanger 4 absorbs heat through evaporation to provide cold for the evaporation chamber, and at the moment, because the second heat exchanger 4 refrigerates, the surfaces of the tube fins of the second heat exchanger 4 continuously frost, the humidity inside the evaporation chamber continuously decreases, and thus the absolute humidity difference of the frost layer ambient air of the first heat exchanger 3 is continuously reduced. This process is continued until the absolute humidity meets the humidity required for defrosting of the frost layer of the first heat exchanger 3.

When the absolute humidity difference of the air around the frost layer reaches a certain condition, the sensible heat of the frost layer is heated to a certain value, and the temperature difference of the defrosting evaporator decreases gradually from the root to the outside, the frost layer can start to sublimate from the root, and the frost layer on the evaporator can integrally fall off after the root frost layer is sublimated under the action of gravity.

Referring to fig. 4, in some embodiments, if it is the second heat exchanger 4 that needs defrosting, the step S200 specifically includes the following steps:

step S221, if the second heat exchanger 4 meets the defrosting condition, the third branch 8 at the upstream of the second heat exchanger 4 is turned on, the second branch 6 is also turned on, the first branch 5 and the fourth branch 9 are both turned off, the second auxiliary branch 15 is turned on, and the first auxiliary branch 14 is turned off, so as to increase the frost layer temperature outside the second heat exchanger 4.

The third branch 8 is not provided with a throttling element, and the refrigerant output by the condenser 2 directly enters the second heat exchanger 4 through the third branch 8. At this time, the second heat exchanger 4 and the condenser 2 act in the same manner, and the refrigerant is also condensed in the second heat exchanger 4. The refrigerant carries out sensible heat exchange in the second heat exchanger 4, and carries out sensible heat heating on the frost layer on the surface of the second heat exchanger 4. The temperature of the frost layer is higher at the side close to the pipe fins and lower at the side far away from the frost layer, and the temperature difference of the frost layer formed by the whole frost layer is gradually reduced from the root to the outside.

Step S222, determining whether the temperature of the frost layer heated by the second heat exchanger 4 reaches a set value.

The temperature of the frost layer may specifically be the root temperature of the frost layer, i.e. the temperature of the lowermost layer of the frost layer. The set value is, for example, from-10 ℃ to-5 ℃. When the temperature of the frost layer at the root of the defrosting evaporator is higher than the set value, it indicates that the temperature condition required for defrosting is met, and at this time, the frost layer is not heated any more, but the humidity of the ambient temperature of the frost layer, that is, the humidity of the environment where the second heat exchanger 4 is located, is changed.

Step S223, if the frost layer temperature on the second heat exchanger 4 reaches the set value, the second branch 6 on the upstream of the first heat exchanger 3 is turned on, and the first branch 5, the third branch 8 and the fourth branch 9 are all turned off, so as to reduce the humidity of the environment where the second heat exchanger 4 is located. In this state, the first auxiliary branch 14 and the second auxiliary branch 15 are also in the open state.

The second branch 6 is conducting, in which case the first heat exchanger 3 acts as an evaporator. The first heat exchanger 3 absorbs heat in an evaporation mode to provide cold for the evaporation chamber, and at the moment, because the first heat exchanger 3 refrigerates, the surface of the tube fin of the first heat exchanger 3 continuously frosts, the humidity inside the evaporation chamber is continuously reduced, and therefore the absolute humidity difference of the frost layer ambient air of the second heat exchanger 4 is continuously reduced. This process is continued until the absolute humidity meets the humidity required for defrosting of the frost layer of the second heat exchanger 4.

step S300, if the temperature of the refrigerant outlet of the first heat exchanger 3 is higher than a set value, the defrosting step of the first heat exchanger 3 is quitted; and if the refrigerant outlet temperature of the second heat exchanger 4 is higher than the set value, the defrosting step of the second heat exchanger 4 is quitted. The defrosting condition may be the surface temperature of each of the first heat exchanger 3 and the second heat exchanger 4, in addition to the refrigerant outlet temperature of the heat exchanger 3 described above. This is not a limitation herein.

When the defrost step is exited, the first branch 5 and the third branch 8 are cut. The second branch 6 and the fourth branch 9 are either or both conductive as required.

Some specific embodiments are described in detail below with reference to fig. 1.

The refrigerator defrosting system comprises a first heat exchanger 3 and a second heat exchanger 4, and the states of a first branch 5, a second branch 6, a third branch 8 and a fourth branch 9 are controlled by the system, so that the temperature fluctuation of a freezing chamber and a refrigerating chamber of the refrigerator defrosting system in a defrosting mode can be improved while the defrosting is realized by utilizing sublimation.

Referring to fig. 1, a schematic diagram of the refrigeration system is shown in fig. 1, and the refrigeration system includes a first heat exchanger 3 and a second heat exchanger 4, a first throttling element 7 and a second throttling element 10, a first branch 5 and a third branch 8. The solenoid valve 13 has 4 outlet ports, in which an outlet port a communicates with the first branch 5, an outlet port b communicates with the second branch 6, an outlet port c communicates with the fourth branch 9, and an outlet port d communicates with the third branch 8, and the flow direction of the refrigerant can be controlled by controlling the opening and closing of the 4 outlet ports.

The defrosting system of the refrigerator comprises two modes: 1 normal refrigeration mode; defrost mode 2

(1) Normal cooling mode

When the refrigeration system is in a normal refrigeration mode, the first branch and the fourth branch corresponding to the outflow ports a and d of the electromagnetic valve 13 are disconnected, the second branch and the third branch corresponding to the outflow ports b and c are connected, refrigerant enters the condenser 2 through the compressor 1, enters the first throttling element 7 and the second throttling element 10 for throttling through b and c in the electromagnetic valve 13 respectively, and is evaporated and absorbed through the first heat exchanger 3 and the second heat exchanger 4, so that the cold quantity requirement of an evaporation chamber is met together. The third 11 and fourth 12 shut-off valves are open and the first 16 and second 17 shut-off valves are closed, ensuring that the refrigerant is finally returned to the compressor 1. Of course, the first heat exchanger 3 and the second heat exchanger 4 may alternatively operate as required.

(2) Defrost mode

When the system is in normal refrigeration mode operation and detects that a certain evaporator (assuming that the first heat exchanger 3 achieves the defrosting condition) achieves the defrosting condition, the whole refrigeration system enters the defrosting mode, the root frost layer temperature of the defrosting evaporator is detected, and the on-off states of the four outflow ports a, b, c and d of the electromagnetic valve 13, the first stop valve 16, the second stop valve 17, the third stop valve 11 and the fourth stop valve 12 are determined according to the root frost layer temperature value of the defrosting evaporator.

When the root frost layer temperature of the defrosting evaporator is detected to be lower than the set value, the first branch 5 is opened, the other three branches are closed, the fourth stop valve 12 and the first stop valve 16 are opened, and the other two stop valves are closed. The refrigerant flows only to the first branch passage 5 through the solenoid valve 13. The refrigerant flows into the defrosting first heat exchanger 3 through the first branch 5 to perform sensible heat exchange, sensible heat heating is performed on a frost layer on the surface of the evaporator, meanwhile, the temperature of the frost layer is higher at the side close to the pipe fins, and the temperature of the frost layer is lower at the side far away from the frost layer, so that the temperature difference that the temperature of the frost layer decreases from the root to the outside is formed. The refrigerant enters the second throttling element 10 through the first stop valve 16 after passing through the first heat exchanger 3, enters the second heat exchanger 4 after throttling for evaporation and refrigeration, so that cold energy is provided for the compartment, at the moment, the surfaces of the pipe fins continue to frost due to the refrigeration of the second heat exchanger 4, the humidity inside the evaporation chamber is continuously reduced, and the absolute humidity difference of the air around the frost layer of the defrosting evaporator is continuously reduced.

When the temperature of the frost layer at the root of the defrosting evaporator is higher than a set value, only the fourth stop valve 12 is opened, and the other three stop valves are closed; and the first branch 5 is closed, only the fourth branch 9 of the electromagnetic valve is opened, and the refrigerant flows into the second heat exchanger 4 through the fourth branch 9 to evaporate and absorb heat, so that cold energy is provided for the compartment. Similarly, the absolute humidity difference of the air around the frost layer of the defrosting evaporator is continuously reduced due to the refrigeration of the second heat exchanger 4. The refrigerant flowing out of the second heat exchanger 4 passes through the fourth shutoff valve 12 and enters the compressor.

When the absolute humidity difference of the air around the frost layer reaches a certain condition, the sensible heat of the frost layer is heated to a certain value, and the temperature difference of the defrosting evaporator decreases gradually from the root to the outside, the frost layer can start to sublimate from the root, and the frost layer on the evaporator can integrally fall off after the root frost layer is sublimated under the action of gravity. Set value

When the defrosting condition that the first heat exchanger 3 is removed from the defrosting condition is detected, the first branch 5 and the third branch 8 are closed, the second branch 6 and the fourth branch 9 are opened simultaneously, the third stop valve 11 and the fourth stop valve 12 are both opened, the first stop valve 16 and the second stop valve 17 are both closed, the defrosting mode of the system is closed, and the normal refrigeration mode is entered.

In the description of the present invention, it is to be understood that the terms "central", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be considered as limiting the scope of the present invention.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: it is to be understood that modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some of the technical features thereof, but such modifications or substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A defrost system for a refrigerator, comprising:

a compressor (1) configured to compress a refrigerant;

a condenser (2), a fluid inlet of the condenser (2) being in communication with a fluid outlet of the compressor (1);

a first heat exchanger (3), wherein a first branch (5) and a second branch (6) are arranged between a fluid inlet of the first heat exchanger (3) and a fluid outlet of the condenser (2) in parallel, the first branch (5) is not provided with a throttling element, and the second branch (6) is provided with a first throttling element (7); the fluid outlet of the first heat exchanger (3) is communicated with the fluid inlet of the compressor (1); and

a third branch (8) and a fourth branch (9) are arranged between a fluid inlet of the second heat exchanger (4) and a fluid outlet of the condenser (2) in parallel, the third branch (8) is not provided with a throttling element, and the fourth branch (9) is provided with a second throttling element (10); the fluid outlet of the second heat exchanger (4) is communicated with the fluid inlet of the compressor (1);

a first auxiliary branch (14), one end of the first auxiliary branch (14) is communicated with the inflow end of the fourth branch (9), the other end of the first auxiliary branch (14) is communicated with the outflow port of the first heat exchanger (3), and the first auxiliary branch (14) is provided with a first stop valve (16); and

one end of the second auxiliary branch (15) is communicated with the inflow end of the second branch (6), the other end of the second auxiliary branch (15) is communicated with the outflow end of the second heat exchanger (4), and a second stop valve (17) is arranged on the second auxiliary branch (15).

2. Defrost system for a refrigerator according to claim 1, characterized in that a third shut-off valve (11) is arranged in common between the fluid outlet of the first heat exchanger (3) and the other end of the first auxiliary branch (14) and the fluid inlet of the compressor (1).

3. Defrost system for a refrigerator according to claim 1, characterized in that a fourth shut-off valve (12) is provided in common between the fluid outlet of the second heat exchanger (4) and the other end of the second auxiliary branch (15) and the fluid inlet of the compressor (1).

4. The defrosting system for a refrigerator of claim 1, further comprising:

and the electromagnetic valve (13) is provided with an inflow port and four outflow ports, the inflow port of the electromagnetic valve (13) is communicated with the fluid outlet of the condenser (2), and the four outflow ports are communicated with the first branch (5), the second branch (6), the third branch (8) and the fourth branch (9) in a one-to-one correspondence manner.

5. The refrigerator defrost system of any one of claims 1-4 configured to bypass one of:

the first branch (5) and the fourth branch (9) are both conducting, the second branch (6) and the third branch (8) are both off, and the first auxiliary branch (14) is conducting; or the fourth branch (9) is on, the first branch (5), the second branch (6) and the third branch (8) are all off, and the first auxiliary branch (14) and the second auxiliary branch (15) are also off; alternatively, the first and second electrodes may be,

the third branch (8) and the second branch (6) are conductive, the first branch (5) and the fourth branch (9) are both open, and the second auxiliary branch (15) is conductive; or, the second branch (6) is on, the first branch (5), the third branch (8) and the fourth branch (9) are all off, and the first auxiliary branch (14) and the second auxiliary branch (15) are also off.

6. The refrigerator defrost system of claim 1, wherein a third shut-off valve (11) is provided in common between the fluid outlet of the first heat exchanger (3) and the other end of the first auxiliary branch (14) and the fluid inlet of the compressor (1);

a fourth stop valve (12) is arranged between the fluid outlet of the second heat exchanger (4) and the other end of the second auxiliary branch (15) and the fluid inlet of the compressor (1) together;

the defrosting system of the refrigerator further comprises a solenoid valve (13), wherein the solenoid valve (13) is provided with an inflow port and four outflow ports, the inflow port of the solenoid valve (13) is communicated with the fluid outlet of the condenser (2), and the four outflow ports are communicated with the first branch (5), the second branch (6), the third branch (8) and the fourth branch (9) in a one-to-one correspondence manner;

in a mode for defrosting the first heat exchanger (3): a first outflow port of the electromagnetic valve (13) is opened, the first stop valve (16) and the fourth stop valve (12) are both opened, the third stop valve (11) and the second stop valve (17) are both closed, and the first branch (5) and the fourth branch (9) are communicated through the first auxiliary branch (14), so that the refrigerant sequentially flows through the first branch (5), the first auxiliary branch (14) and the fourth branch (9); or, a fourth outlet (d) of the solenoid valve (13) is opened, the first stop valve (16), the third stop valve (11) and the second stop valve (17) are all closed, and the fourth stop valve (12) is opened, so that the refrigerant only flows through the fourth branch (9); or

In a mode for defrosting the second heat exchanger (4): a third outlet (c) of the electromagnetic valve (13) is opened, the second stop valve (17) and the third stop valve (11) are opened, the fourth stop valve (12) and the first stop valve (16) are both closed, and the third branch (8) and the second branch (6) are communicated through the second auxiliary branch (15), so that the refrigerant sequentially flows through the third branch (8), the second auxiliary branch (15) and the second branch (6); or, the second outlet (b) of the solenoid valve (13) is opened, the first stop valve (16), the second stop valve (17) and the fourth stop valve (12) are all closed, and the third stop valve (11) is opened, so that the refrigerant only flows through the second branch (6).

7. Defrost system for a refrigerator according to any of the claims 1-4, characterized in that the first throttle element (7) comprises a capillary tube and/or an electronic expansion valve; and/or the second throttling element (10) comprises a capillary tube and/or an electronic expansion valve.

8. A refrigerator comprising the defrosting system for a refrigerator according to any one of claims 1 to 7.

9. A defrosting method for a refrigerator, which is performed by using the defrosting system for a refrigerator according to any one of claims 1 to 7, and which comprises the steps of:

10. The method for defrosting a refrigerator according to claim 9, wherein if the first heat exchanger satisfies a defrosting condition, the method for defrosting the first heat exchanger by connecting the first heat exchanger and the condenser in series to increase the temperature of the frost layer outside the first heat exchanger and reduce the humidity of the environment in which the first heat exchanger is located includes the following steps:

11. The defrosting method for a refrigerator according to claim 9, wherein if the second heat exchanger satisfies a defrosting condition, the method increases the temperature of the frost layer outside the second heat exchanger by connecting the condenser and the second heat exchanger in series, and reduces the humidity of the environment in which the second heat exchanger is located, so as to defrost the second heat exchanger, and specifically comprises the following steps:

12. The defrosting method for a refrigerator of claim 9, further comprising the steps of:

13. The defrosting method for a refrigerator according to claim 9, further comprising the following steps before the determining whether the first heat exchanger and the second heat exchanger of the refrigerator satisfy the defrosting condition: