CN107192206B

CN107192206B - Defrosting method for refrigerator

Info

Publication number: CN107192206B
Application number: CN201710516068.9A
Authority: CN
Inventors: 苗建林; 娄喜才; 姬立胜; 王铭
Original assignee: Qingdao Haier Co Ltd
Current assignee: Qingdao Haier Co Ltd
Priority date: 2017-06-29
Filing date: 2017-06-29
Publication date: 2019-12-10
Anticipated expiration: 2037-06-29
Also published as: CN107192206A

Abstract

the invention provides a defrosting method of a refrigerator. The defrosting method comprises the following steps: judging whether the evaporator needs defrosting or not; when the evaporator needs defrosting, all the heating wires are turned on to enable each heating wire to generate heat to defrost; detecting defrosting temperature; detecting the pressure difference among a plurality of different heights of the evaporator by using a plurality of pressure difference detection devices to obtain a plurality of first pressure difference values; and closing part or all of the heating wires according to the defrosting temperature and/or each first pressure difference value. The defrosting method can properly reduce the heat release of the heating wires at different positions, so that the evaporator of the refrigerator can be defrosted as required, thereby reducing the power consumption, reducing the defrosting time and enhancing the fresh-keeping effect.

Description

Defrosting method for refrigerator

Technical Field

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

Background

the refrigerator is a refrigerating device for keeping constant low temperature, and is a civil product for keeping food or other articles in a constant low-temperature cold state. The air cooling technology cools air passing through a built-in hidden cooler (such as an evaporator of a refrigerant circulating system), and forces cold air to flow in a circulating manner through a fan, so that the cold air is uniformly distributed in each compartment of the refrigerator, and the refrigeration is realized. When air in the refrigerator passes through the surface of the evaporator, moisture in the air is condensed on the surface of the evaporator, and because the temperature of the evaporator is too low, a frost layer is formed after a period of time, the heat transfer efficiency of the evaporator is reduced until the evaporator is completely blocked and loses efficacy, the operation efficiency of the refrigerator is reduced, and defrosting must be carried out after the operation for a period of time.

In the existing defrosting, an electric heater is usually arranged at the bottom of an evaporator, when a frost layer on the surface of the evaporator reaches a certain thickness, a refrigerator stops refrigerating, and the heater starts to work to heat and melt the frost layer. In the defrosting process of the evaporator, the bottom of the evaporator is heated firstly, so that the frost at the bottom of the evaporator begins to melt firstly, and the frost at the middle part and the upper part of the evaporator gradually melts, so that the bottom of the evaporator is heated by the heater for a longer time, and the plastic part at the bottom of the evaporator is easily aged and damaged due to long heating time. The frost on the evaporator absorbs a large amount of heat in the process of gradually melting into water from bottom to top, the melting time is long, and the phenomenon of serious heat waste exists.

Disclosure of Invention

The inventor thinks that the existing defrosting mode of the interior of the refrigerator is basically defrosting according to an empirical value, but the defrosting speed of the interior of the refrigerator is different according to the normal use condition and the change of the environment, the defrosting speed of different positions of the evaporator is also different for the evaporator due to the relation of wind directions and the like, the electric heater is arranged at the bottom of the evaporator for defrosting, the frost on the evaporator absorbs a large amount of heat in the process of gradually melting into water from bottom to top, the melting time is long, and the phenomenon of serious heat waste exists.

Therefore, the present invention is directed to a defrosting method for a refrigerator, which can defrost an evaporator as required, wherein defrosting as required includes not only defrosting according to frosting positions of the evaporator, but also applying appropriate heat according to the amount of a frost layer at each position, and it is very important to defrost different positions of the evaporator as required, thereby reducing power consumption, reducing defrosting time, and enhancing fresh-keeping effect.

Specifically, the present invention provides a defrosting method of a refrigerator, wherein the refrigerator includes an evaporator, a plurality of heating wires, and a plurality of pressure difference detecting devices; each heating wire extends along the horizontal direction, and the plurality of heating wires are arranged at intervals along the height direction of the evaporator; each heating wire is configured to directly or indirectly heat the evaporator; each of the pressure difference detecting means is configured to detect a pressure difference between two different heights of the evaporator, and the plurality of pressure difference detecting means is configured to detect a pressure difference between a plurality of different heights of the evaporator; and the defrosting method comprises the following steps:

judging whether the evaporator needs defrosting or not;

when the evaporator needs defrosting, all heating wires are turned on to enable each heating wire to generate heat to defrost;

Detecting defrosting temperature; detecting pressure differences among a plurality of different heights of the evaporator by using a plurality of pressure difference detection devices to obtain a plurality of first pressure difference values;

and closing part or all of the heating wires according to the defrosting temperature and/or each first pressure difference value.

alternatively, the timing of detecting the pressure difference between the plurality of different levels of the evaporator using the plurality of pressure difference detecting means is determined according to the defrosting temperature.

Optionally, closing part or all of the heating wires according to the defrosting temperature and/or each first pressure difference comprises:

And closing all the heating wires when the defrosting temperature reaches a first preset temperature value.

optionally, each pressure difference detection device is configured to work in cooperation with at least one heating wire; and the defrosting method also comprises the following steps:

Acquiring an initial value of a pressure difference between a plurality of different heights of the evaporator;

closing part or all of the heating wires according to the defrosting temperature and/or each first pressure difference comprises:

When each first pressure difference value is less than or equal to its corresponding initial value, at least one heating wire working in cooperation with the pressure difference detection means from which the first pressure difference value is derived is closed.

Optionally, detecting pressure differences among a plurality of different heights of the evaporator by using a plurality of pressure difference detection devices when the defrosting temperature reaches a second preset temperature value; the second preset temperature value is smaller than the first preset temperature value.

Optionally, detecting pressure differences among a plurality of different heights of the evaporator by using a plurality of pressure difference detection devices when the defrosting temperature reaches a third preset temperature value; the third preset temperature value is smaller than the first preset temperature value and is larger than the second preset temperature value; or the like, or, alternatively,

When the defrosting temperature reaches a second preset temperature value, when the defrosting temperature is increased by a preset temperature difference value, a plurality of pressure difference detection devices are used for detecting the pressure difference among a plurality of different heights of the evaporator.

Optionally, each pressure difference detecting device operates the blower of the refrigerator at a first preset voltage when detecting a pressure difference between two different heights of the evaporator, and each pressure difference detecting device outputs a plurality of first detection values within a first preset time, and the first pressure difference value corresponding to the pressure difference detecting device is the largest first detection value output by the pressure difference detecting device.

Optionally, obtaining an initial value of a pressure difference between a plurality of different heights of the evaporator comprises:

when the refrigerator is started, the refrigerator normally operates for a preset time, then a fan of the refrigerator operates at a second preset voltage, and each pressure difference detection device outputs a plurality of second detection values within second preset time;

An average value of the plurality of second detection values output by each pressure difference detection device is calculated, and the initial value corresponding to the pressure difference detection device is the average value of the plurality of second detection values output by the pressure difference detection device.

Optionally, determining whether the evaporator requires defrosting comprises:

After each initial value is obtained or within a third preset time after defrosting is finished each time, the fan normally works; after each initial value is obtained or at a third preset time after defrosting is finished each time, enabling the fan to operate at a third preset voltage, outputting a plurality of third detection values within a fourth preset time by each pressure difference detection device, and enabling the maximum third detection value output by the pressure difference detection device to be a second pressure difference value so as to obtain a plurality of second pressure difference values;

If the one or more second pressure difference values are larger than or equal to the respective corresponding threshold values, judging that the evaporator needs defrosting; if not, enabling the fan to normally work for a fifth preset time, then circularly entering to enable the fan to operate under a third preset voltage, outputting a plurality of third detection values by each pressure difference detection device within a fourth preset time, and enabling the maximum third detection value output by the pressure difference detection device to be a second pressure difference value so as to obtain a plurality of second pressure difference values;

The fifth preset time is less than the third preset time;

Each threshold value is greater than or equal to an initial value corresponding to the threshold value.

optionally, when the evaporator needs defrosting, at least an air inlet door of the storage compartment of the refrigerator is closed;

The refrigerator also comprises a temperature sensor, wherein the temperature sensor is arranged above the evaporator and is configured to detect defrosting temperature;

The two pressure difference detection devices comprise a first pressure difference detection device and a second pressure difference detection device;

a first pressure difference detecting means configured to detect a pressure difference between the bottom end and the upper end of the evaporator and configured to work in cooperation with a lowermost set of heating wires, the lowermost set of heating wires comprising at least one heating wire;

the second pressure difference detection device is configured to detect the pressure difference between the middle part and the upper end of the evaporator, and is configured to work in cooperation with all the heating wires above the lowest group of the heating wires;

Each of the pressure difference detecting means is a differential pressure sensor.

The defrosting method of the refrigerator can properly reduce the heat release quantity of the heating wires at different positions according to the frosting quantity and the defrosting temperature of different positions on the evaporator and the pressure difference among a plurality of different heights of the evaporator, so that the evaporator of the refrigerator can be defrosted as required, and the defrosting of different positions of the evaporator is very important as required, thereby reducing the power consumption, reducing the defrosting time and enhancing the fresh-keeping effect.

Furthermore, the refrigerator can judge the frosting degree of the evaporator according to the pressure difference among a plurality of different heights of the evaporator so as to judge whether the evaporator needs to be defrosted, is quick and accurate, and accurately and effectively enters the defrosting operation, so that the frost attached to the evaporator can be timely melted, the defrosting operation is avoided when defrosting is unnecessary, and electric energy is saved.

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

Drawings

Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

Fig. 1 is a schematic structural view of a refrigerator according to one embodiment of the present invention;

Fig. 2 is a schematic partial structural view of a refrigerator according to one embodiment of the present invention;

FIG. 3 is a schematic side view of the structure shown in FIG. 2;

Fig. 4 is a schematic flowchart of a defrosting method of a refrigerator according to one embodiment of the present invention.

Detailed Description

fig. 1 is a schematic structural view of a refrigerator according to one embodiment of the present invention; fig. 2 is a schematic partial structural view of a refrigerator according to one embodiment of the present invention; fig. 3 is a schematic side view of the structure shown in fig. 2. As shown in fig. 1, 2 and 3, an embodiment of the present invention provides a refrigerator. The refrigerator can comprise a refrigerator body 10, a door body, a refrigerating system, a fan, a frosting condition detection device, a defrosting heating device and a temperature sensor.

the box body 10 has a plurality of storage compartments therein. The storage compartment is used for storing food. The plurality of storage compartments in the embodiment of the present invention may include a refrigerating compartment 11 for frequently storing vegetables, and the temperature control range thereof is generally-5 ℃ to 7 ℃. The plurality of storage compartments may further include a freezing compartment 12, a warming compartment, and the like. The door body can be a plurality of, and every door body is configured to the controlled opening or closes a storing compartment. Further, the box body 10 is also provided with a compressor chamber, a cooling chamber, and an air duct system for communicating the storage chamber and the cooling chamber. The cooling compartment may be at the rear side of the freezing compartment 12. In fig. 1, a duct cover between the cooling compartment and the freezing compartment 12 is not shown.

the refrigeration system is configured to provide cooling energy to reduce a temperature within the storage compartment. Specifically, the refrigeration system may be a compression-type refrigeration system including a compressor, a condenser, a throttling device, an evaporator 20, and the like. The compressor may be disposed within the compressor bin. The evaporator 20 may be disposed in the cooling chamber and configured to reduce a temperature of gas in the cooling chamber by using a refrigerant introduced therein to maintain a temperature in the storage compartment at a predetermined temperature or within a predetermined temperature range via the duct system. The fan may be configured to cause airflow from the cooling compartment to the storage compartment and from the storage compartment back to the cooling compartment, and to cause airflow within the cooling compartment from the lower end to the upper end of the evaporator 20.

The frosting condition detection device can be arranged in the cooling chamber and used for enabling the refrigerator to judge whether the refrigerator needs to be defrosted according to the detection result of the frosting condition detection device. The frost condition detection means may include a plurality of pressure difference detection means 60. Each of the pressure difference detecting devices 60 is configured to detect a pressure difference between two different heights of the evaporator 20, and the plurality of pressure difference detecting devices 60 are configured to detect a pressure difference between a plurality of different heights of the evaporator. Each differential pressure detecting means 60 is preferably a differential pressure sensor. A plurality of pressure difference detecting means 60 may be provided at intervals along the length direction of the evaporator 20. In refrigerators, the airflow generally flows from the lower end of the evaporator to the upper end. The magnitude of the pressure differential between the various heights of the evaporator reflects the wind resistance across the evaporator, with a greater pressure differential indicating a greater wind resistance across the evaporator, and a thicker layer of frost may be applied to the surface evaporator 20, providing greater resistance to wind. The frosting condition detection device is particularly suitable for the refrigerator with a longer and/or higher evaporator 20, can enable the detection structure to be more accurate, and can accurately and effectively enter the defrosting operation, so that the frost attached to the evaporator can be timely melted, the defrosting operation is avoided when the defrosting is unnecessary, and the electric energy is saved.

the defrosting heating means may have a plurality of heating wires 40. Each of the heating wires 40 may extend in a horizontal direction, and a plurality of the heating wires 40 are spaced apart in a height direction of the evaporator 20, and each of the heating wires 40 is configured to directly or indirectly heat the evaporator 20, so that the plurality of the heating wires 40 can heat the evaporator 20 at a plurality of different height positions. Further, the defrosting heating device may further include a heat conductive plate 30. The heat conductive plate 30 is disposed at one side of the evaporator 20 and thermally contacts (i.e., performs contact thermal connection) the evaporator 20. Each heating wire 40 is in thermal contact with the thermally conductive plate 30. The heat conductive plate 30 can be used to diffuse heat from the heating wires 40 to the evaporator 20, thereby improving defrosting efficiency. In some preferred embodiments of the present invention, the heat conductive plate 30 is disposed between the plurality of heating wires 40 and the evaporator 20 to transfer heat generated from each heating wire 40 to the evaporator 20. In other preferred embodiments, a plurality of heating wires 40 are disposed within thermally conductive plate 30.

the temperature sensor is preferably disposed above the evaporator 20, and is configured to detect a defrosting temperature of the evaporator 20. In some alternative embodiments, the temperature sensor may be disposed on the evaporator.

In particular, each pressure difference detection device 60 may be configured to work in cooperation with at least one heating wire 40. For example, the pressure difference detection means 60 is two, and includes a first pressure difference detection means and a second pressure difference detection means. The first pressure difference detecting means is configured to detect a pressure difference between the bottom end and the upper end of the evaporator and is configured to work in cooperation with a lowermost set of heating wires 40, the lowermost set of heating wires 40 comprising at least one heating wire 40. The second pressure difference detecting means is configured to detect the pressure difference between the middle and the upper end of the evaporator and is configured to work in cooperation with all the heating wires 40 above the lowermost group of heating wires. For another example, when the height range of the evaporator detected by each pressure difference detecting device 60 does not overlap or slightly overlaps with the height ranges detected by the other pressure difference detecting devices, at least one heating wire 40 may be disposed within the height range of the evaporator detected by each pressure difference detecting device 60. For another example, the cooperation of the pressure difference detecting device and the heating wire 40 may be artificially configured in other forms to better fulfill the demand of defrosting on demand.

fig. 4 is a schematic flowchart of a defrosting method of a refrigerator according to one embodiment of the present invention. As shown in fig. 4, in particular, the embodiment of the invention also provides a defrosting method of a refrigerator. The highest heating power of each heating wire 40 may preferably be the same, i.e. the same plurality of heating wires 40 is used. Of course, heating wires 40 of different heating powers may also be used. The defrosting method can comprise the following steps:

It is determined whether the evaporator 20 needs defrosting.

When the evaporator 20 needs defrosting, all the heating wires 40 are turned on, so that each heating wire 40 is heated to defrost. Further, when the evaporator 20 needs defrosting, at least the air intake door of the storage compartment of the refrigerator is closed.

the defrosting temperature is detected, and the pressure differences between the different heights of the evaporator 20 are detected by the pressure difference detecting devices 60 to obtain a plurality of first pressure difference values.

Some or all of the heating wires 40 are closed according to the defrosting temperature and/or each of the first pressure difference values.

For example, in some embodiments of the present invention, when the defrosting temperature reaches the first preset temperature value, all the heating wires 40 are turned off to complete defrosting. The temperature sensor is preferably disposed above the evaporator 20; the first preset temperature value is preferably 6.6 ℃ to 7.4 ℃, e.g. 6.9 ℃, 7 ℃ etc. In some embodiments of the invention, the defrosting method further comprises: initial values of pressure differences between a plurality of different levels of evaporator 20 are obtained. Closing part or all of the heating wires 40 according to the defrosting temperature and/or each first pressure difference comprises: when each first pressure difference value is less than or equal to its corresponding initial value, at least one of the heating wires 40 operating in cooperation with the pressure difference detecting means 60 that obtained the first pressure difference value is turned off.

in this embodiment, the evaporator 20 has a higher frosting speed at a part of positions and a lower frosting speed at a part of positions, and some heating wires 40 can be properly turned off first during defrosting, so that defrosting can be realized as required, and a frost layer at a thinner part of the evaporator can obtain proper heat, thereby saving electric energy. That is to say, this kind of heating defrosting mode can effectively reduce the defrosting time to in the defrosting process, whole defrosting needs the power consumption to reduce, and can effectively reduce refrigerator inside temperature fluctuation.

In some preferred embodiments of the present invention, the timing of detecting the pressure difference between different heights of the evaporator 20 by using the plurality of pressure difference detecting devices 60 may be determined according to the defrosting temperature, so as to better determine the timing of ending the defrosting, shorten the defrosting time, thereby improving the efficiency of the refrigerator and saving energy.

Specifically, in some embodiments of the present invention, when the defrosting temperature reaches the second preset temperature value, the pressure difference between different heights of the evaporator 20 may be detected by using a plurality of pressure difference detecting devices 60. The second preset temperature value is smaller than the first preset temperature value. The second predetermined temperature value may be 3.6 ℃ to 4.4 ℃, such as 3.9 ℃, 4 ℃, and the like. Further, a plurality of pressure difference detecting devices 60 may be used to detect pressure differences between different heights of the evaporator 20 when the defrosting temperature reaches a third preset temperature value. The third preset temperature value is smaller than the first preset temperature value, and the third preset temperature value is larger than the second preset temperature value. The third predetermined temperature may be 5 deg.C to 6 deg.C, such as 5 deg.C, 5.2 deg.C, 5.5 deg.C, 5.6 deg.C, 6 deg.C, etc.

in still further embodiments of the present invention, after the defrosting temperature reaches the second preset temperature value, the pressure differences between the different heights of the evaporator 20 are detected by the pressure difference detecting devices 60 every time the defrosting temperature is increased by the preset temperature difference. The preset temperature difference may be 0.3 to 0.8 ℃. For example, the second preset temperature value may be 4 ℃ and the preset temperature difference value may be 0.5 ℃, so that the pressure differences between different heights of the evaporator 20 may be detected by the plurality of pressure difference detecting devices 60 at 4.5 ℃, 5 ℃, 5.5 ℃ and the like.

preferably, when each of the pressure difference detecting means 60 detects a pressure difference between two different heights of the evaporator 20, the fan is operated at a first preset voltage, each of the pressure difference detecting means 60 outputs a plurality of first detection values for a first preset time, and the first pressure difference value corresponding to the pressure difference detecting means 60 is the largest first detection value output by the pressure difference detecting means 60. The first preset voltage may be 11V to 13V, for example, 11V, 12V, 13V. The first preset time may be 1.5s to 4s, for example, 1.5s, 1.8s, 2s, 2.2s, 3s, 3.5s, etc.

in some embodiments of the present invention, obtaining an initial value of the pressure difference between the plurality of different heights of evaporator 20 may include: when the refrigerator is started, the refrigerator is normally operated for a preset time, then the fan is operated at a second preset voltage, and each pressure difference detection device 60 outputs a plurality of second detection values within a second preset time. An average value of the plurality of second detection values output by each of the pressure difference detection devices 60 is calculated, and the initial value corresponding to the pressure difference detection device is the average value of the plurality of second detection values output by the pressure difference detection device. The preset time period may be 2min to 6min, such as 3min, 4min, 5min, etc. The second preset voltage may be 11V to 13V, for example, 11V, 12V, 13V. The second preset time may be 50s to 80s, preferably 60s, 70s, etc. Furthermore, at least the air inlet door of the storage compartment of the refrigerator can be closed during detection. In some alternative embodiments, when the refrigerator is turned on, the blower may be directly operated at the second preset voltage without normally operating the refrigerator for a preset time period. In other alternative embodiments, the initial values may be preset values, and the refrigerator is directly set during development.

In some embodiments of the present invention, it is preferable to determine whether defrosting of the evaporator 20 is required by using the detection result of the pressure difference detecting device 60. Specifically, determining whether the evaporator 20 needs defrosting includes:

after the initial value is obtained or within a third preset time after defrosting is finished each time, the fan normally works (namely, the refrigerator normally works). The third predetermined time may be 3H to 5H, for example, 3.8H, 4H, 4.5H, etc. Further, after the initial value is obtained or at a third preset time after each defrosting is completed, the blower is operated at a third preset voltage, each pressure difference detection device 60 may output a plurality of third detection values within a fourth preset time, and the maximum third detection value output by the pressure difference detection device 60 is one second pressure difference value to obtain a plurality of second pressure difference values. The third preset voltage may be 11V to 13V, for example, 11V, 12V, 13V. The fourth preset time may be 8s to 12s, preferably 9s, 10s, etc.

if the one or more second pressure difference values are greater than or equal to the respective corresponding threshold values, it is determined that the evaporator 20 needs defrosting; if not, the fan works normally for a fifth preset time, then the fan operates at a third preset voltage in a circulating mode, each pressure difference detection device 60 can output a plurality of third detection values within a fourth preset time, and the maximum third detection value output by the pressure difference detection device 60 is a second pressure difference value, so that a plurality of second pressure difference values are obtained. The fifth predetermined time may be 0.6H to 1.5H, for example, 0.8H, 1H, 1.25H, etc. The threshold values may be preset, each of which is greater than or equal to an initial value corresponding to the threshold value. In some alternative embodiments, it may be determined whether each of the second pressure difference values is greater than or equal to an initial value corresponding to the pressure difference detecting means 60 that obtained the second pressure difference value, to determine whether the evaporator 20 needs defrosting directly according to the result of comparison with the initial value.

in some alternative embodiments of the present invention, whether the evaporator 20 needs defrosting may also be judged according to a continuous operation time of a compressor of the refrigerator and/or a total operation time of the compressor. Whether the evaporator 20 needs defrosting or not can also be judged according to the temperature detected by the temperature sensor.

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

Claims

1. A defrosting method of a refrigerator, wherein the refrigerator includes an evaporator, a plurality of heating wires, and a plurality of pressure difference detecting devices; each heating wire extends along the horizontal direction, and the plurality of heating wires are arranged at intervals along the height direction of the evaporator; each of the heating wires is configured to directly or indirectly heat the evaporator; each of the pressure difference detecting means is configured to detect a pressure difference between two different heights of the evaporator, and a plurality of the pressure difference detecting means is configured to detect a pressure difference between a plurality of different heights of the evaporator; and the defrosting method comprises:

Judging whether the evaporator needs defrosting or not;

when the evaporator needs defrosting, all the heating wires are turned on to enable each heating wire to generate heat to defrost;

Detecting defrosting temperature; detecting the pressure difference among a plurality of different heights of the evaporator by using a plurality of pressure difference detection devices to obtain a plurality of first pressure difference values;

Closing part or all of the heating wires according to the defrosting temperature and/or each first pressure difference value; and is

Determining the time for detecting the pressure difference among a plurality of different heights of the evaporator by using a plurality of pressure difference detection devices according to the defrosting temperature;

Closing part or all of the heating wires according to the defrosting temperature and/or each of the first pressure difference values comprises: when the defrosting temperature reaches a first preset temperature value, all the heating wires are closed;

when the defrosting temperature reaches a second preset temperature value, detecting pressure differences among a plurality of different heights of the evaporator by using a plurality of pressure difference detection devices; the second preset temperature value is smaller than the first preset temperature value.

2. The defrosting method according to claim 1, wherein

Each of the pressure difference detecting means is configured to work in cooperation with at least one of the heating wires; and is

The defrosting method further comprises the following steps:

Closing part or all of the heating wires according to the defrosting temperature and/or each of the first pressure difference values comprises:

when each of the first pressure difference values is less than or equal to the initial value corresponding thereto, at least one of the heating wires operating in cooperation with the pressure difference detection means from which the first pressure difference value is derived is turned off.

3. the defrosting method according to claim 1, wherein

When the defrosting temperature reaches a third preset temperature value, detecting pressure differences among a plurality of different heights of the evaporator by using a plurality of pressure difference detection devices; the third preset temperature value is smaller than the first preset temperature value, and the third preset temperature value is larger than the second preset temperature value; or the like, or, alternatively,

and after the defrosting temperature reaches the second preset temperature value, detecting the pressure difference among a plurality of different heights of the evaporator by using a plurality of pressure difference detection devices when the defrosting temperature is increased by a preset temperature difference value.

4. The defrosting method according to claim 1, wherein

When each pressure difference detection device detects the pressure difference between two different heights of the evaporator, the fan of the refrigerator is operated under a first preset voltage, each pressure difference detection device outputs a plurality of first detection values within a first preset time, and the first pressure difference value corresponding to the pressure difference detection device is the largest first detection value output by the pressure difference detection device.

5. The defrosting method according to claim 2, wherein

the acquiring an initial value of a pressure difference between a plurality of different heights of the evaporator includes:

When the refrigerator is started, the refrigerator normally operates for a preset time, then a fan of the refrigerator operates at a second preset voltage, and each pressure difference detection device outputs a plurality of second detection values within the second preset time;

an average value of the plurality of second detection values output by each of the pressure difference detection means is calculated, and the initial value corresponding to the pressure difference detection means is the average value of the plurality of second detection values output by the pressure difference detection means.

6. The defrosting method according to claim 5, wherein

the judging whether the evaporator needs defrosting comprises the following steps:

after each initial value is obtained or within a third preset time after defrosting is finished each time, the fan works normally; after each initial value is obtained or at a third preset time after defrosting is finished each time, enabling the fan to operate at a third preset voltage, enabling each pressure difference detection device to output a plurality of third detection values within a fourth preset time, and enabling the largest third detection value output by the pressure difference detection device to be a second pressure difference value so as to obtain a plurality of second pressure difference values;

if one or more of the second pressure difference values are larger than or equal to the respective corresponding threshold values, judging that the evaporator needs defrosting; otherwise, enabling the fan to normally work for a fifth preset time, then circularly entering the state where the fan is enabled to operate under a third preset voltage, enabling each pressure difference detection device to output a plurality of third detection values within a fourth preset time, and enabling the largest third detection value output by the pressure difference detection device to be a second pressure difference value so as to obtain a plurality of second pressure difference values;

The fifth preset time is less than the third preset time;

each of the threshold values is greater than or equal to the initial value corresponding to the threshold value.

7. The defrosting method according to claim 1, wherein

when the evaporator needs defrosting, at least closing an air inlet door of a storage compartment of the refrigerator;

the refrigerator further comprises a temperature sensor disposed above the evaporator and configured to detect the defrosting temperature;

the first pressure difference detecting means is configured to detect a pressure difference between a bottom end and an upper end of the evaporator, and is configured to work in cooperation with a lowermost set of the heating wires including at least one heating wire;

The second pressure difference detecting means is configured to detect a pressure difference between a middle portion and an upper end of the evaporator, and is configured to operate in cooperation with all of the heating wires above a lowermost group of the heating wires;