Refrigerating and defrosting system, refrigerating device and control method of refrigerating device

Abstract

The invention provides a refrigerating and defrosting system, a refrigerating device and a control method of the refrigerating device, and belongs to the technical field of household appliances. According to the system, switching between defrosting and refrigerating can be carried out through opening and closing control over the defrosting electromagnetic valve and the refrigerating electromagnetic valve, and the efficient and energy-saving hot air defrosting effect is achieved. Meanwhile, the defrosting circulation loop and the refrigeration circulation loop share the evaporator, the refrigeration return air heat exchange device, the defrosting return air heat exchange device, the liquid-gas separator and the compressor, arrangement of components can be reduced, and the system is simple in structure and low in cost. In addition, through the arrangement of the liquid-gas separator, liquid impact of the compressor can be effectively prevented.

Description

Technical Field

[0001] The present application relates to the technical field of household appliances, and in particular to a refrigeration and defrosting system, a refrigeration device and a control method thereof. Background Art

[0002] Refrigeration devices such as refrigerators and freezers are civilian products that keep food or other items at a constant low temperature.

[0003] In the related art, a refrigerator generally includes a box body, and a plurality of refrigeration compartments are arranged in the box body for storing food, beverages or other items that need to be kept at low temperatures. A refrigeration system is also arranged in the box body, and the refrigerator realizes refrigeration of the freezer and refrigerator compartments through the refrigeration system. Due to the particularity of the working principle of refrigerator refrigeration, the refrigerant evaporates and absorbs heat when passing through the evaporator, and the surface of the evaporator will have different degrees of frost. If the defrosting process is not performed in time, the thickness of the frost layer on the surface of the evaporator will gradually increase, and the cooling capacity will decrease, resulting in a low working efficiency of the refrigerator. Therefore, the refrigerator needs to be defrosted.

[0004] However, the existing defrosting generally uses electric heating to defrost the evaporator. The equipment using electric heating to defrost has the following disadvantages in application:

[0005] 1. High energy consumption;

[0006] 2. The electric heating tube is inserted into the middle or lower part of the evaporator, the heating temperature of the entire evaporator is uneven, and the defrosting is not thorough;

[0007] 3. The structure is complex and the cost is high, and the risk of electric leakage of the electric heating tube is high. Summary of the invention

[0008] The main purpose of the embodiments of the present application is to propose a refrigeration and defrost system, a refrigeration device and a control method thereof, aiming to propose a refrigeration and defrost system that can switch between refrigeration and defrosting to achieve an efficient and energy-saving hot gas defrosting effect, and has a simple system structure and low cost.

[0009] To achieve the above-mentioned purpose, the embodiment of the present application proposes a refrigeration and defrosting system, including a compressor, a refrigeration solenoid valve, a defrosting solenoid valve, a condensation heat exchange device, a refrigeration capillary, a defrosting capillary, an evaporator, a refrigeration return air heat exchange device, a defrost return air heat exchange device and a liquid-gas separator;

[0010] The first end of the compressor is communicated with the first end of the refrigeration solenoid valve, the second end of the refrigeration solenoid valve is communicated with the first end of the condensation heat exchange device, the second end of the condensation heat exchange device is communicated with the first end of the refrigeration return air heat exchange device, the second end of the refrigeration return air heat exchange device is communicated with the first end of the refrigeration capillary tube, the second end of the refrigeration capillary tube is communicated with the first end of the evaporator, the second end of the evaporator is communicated with the third end of the refrigeration return air heat exchange device, the fourth end of the refrigeration return air heat exchange device is communicated with the first end of the defrost return air heat exchange device, the second end of the defrost return air heat exchange device is communicated with the first end of the liquid-gas separator, and the second end of the liquid-gas separator is communicated with the second end of the compressor;

[0011] The first end of the compressor is also connected to the first end of the defrost solenoid valve, the second end of the defrost solenoid valve is connected to the third end of the defrost return air heat exchange device, the fourth end of the defrost return air heat exchange device is connected to the first end of the defrost capillary, and the second end of the defrost capillary is connected to the first end of the evaporator.

[0012] The above technical solution has the following advantages or beneficial effects:

[0013] The embodiment of the present application proposes a refrigeration defrost system, which can switch between defrosting and refrigeration by opening and closing the defrost solenoid valve and the refrigeration solenoid valve, so as to achieve an efficient and energy-saving hot gas defrosting effect. At the same time, the defrost cycle and the refrigeration cycle share the evaporator, the refrigeration return air heat exchange device, the defrost return air heat exchange device, the liquid-gas separator and the compressor, which can reduce the layout of components, making the system structure simple and low-cost. In addition, by setting the liquid-gas separator, the compressor liquid hammer can be effectively prevented.

[0014] In one embodiment of the present application, the system includes a refrigeration cycle loop, which includes the compressor, the refrigeration solenoid valve, the condensation heat exchange device, the refrigeration return air heat exchange device, the refrigeration capillary, the evaporator, the refrigeration return air heat exchange device, the defrost return air heat exchange device, the liquid-gas separator and the compressor, which are connected in sequence to form a loop.

[0015] The above technical solution has the following advantages or beneficial effects:

[0016] The refrigeration and defrosting system includes a refrigeration cycle loop. By controlling the refrigeration solenoid valve to close, the refrigeration cycle loop can be realized to achieve the refrigeration effect.

[0017] In one embodiment of the present application, the system also includes a defrost circulation loop, which includes the compressor, the defrost solenoid valve, the defrost return air heat exchange device, the defrost capillary, the evaporator, the refrigeration return air heat exchange device, the defrost return air heat exchange device, the liquid-gas separator and the compressor, which are connected in sequence to form a loop.

[0018] The above technical solution has the following advantages or beneficial effects:

[0019] The refrigeration defrost system also includes a defrost circulation loop. By controlling the defrost solenoid valve to close, the defrost circulation loop can be realized to perform hot gas defrosting on the evaporator.

[0020] To achieve the above-mentioned purpose, the embodiment of the present application provides a defrost control method for a refrigeration device, the refrigeration device comprising:

[0021] The box body, which serves as the supporting structure of the refrigeration device, is equipped with an evaporator bin and several refrigeration compartments;

[0022] The refrigeration and defrosting system described in any embodiment of the present application is arranged in the box, and the refrigeration and defrosting system includes an evaporator, and the evaporator is arranged in the evaporator bin, and the evaporator bin has an air outlet and an air inlet, and the air outlet and the air inlet are both provided with dampers, and the evaporator bin and the refrigeration compartment are isolated or connected by the dampers;

[0023] an evaporating fan, arranged in the evaporator bin, for driving air from the evaporator bin into the refrigerating compartment;

[0024] A frost water sensor is arranged on the surface of the evaporator and is used to detect the frosting condition of the evaporator;

[0025] A first temperature sensor is disposed in the refrigeration room and is used to collect the refrigeration room temperature in the refrigeration room;

[0026] The defrost control method comprises:

[0027] Determining whether to turn on the defrost mode according to the resistance value collected by the frost water sensor;

[0028] When the defrost mode is turned on, the refrigeration solenoid valve in the refrigeration and defrost system is controlled to be in a conducting state, the defrost solenoid valve is in a disconnected state, and the evaporation fan is controlled to remain in an on state, and the damper is in an open state, so as to refrigerate the refrigeration compartment;

[0029] When it is detected that the refrigeration compartment temperature collected by the first temperature sensor is less than or equal to the preset temperature, or the refrigeration time after the defrost mode is turned on is greater than or equal to the preset time, the refrigeration solenoid valve is controlled to switch to the disconnected state, the defrost solenoid valve is switched to the on state, the evaporating fan is controlled to switch to the stopped state, and the damper is switched to the closed state for defrosting.

[0030] The above technical solution has the following advantages or beneficial effects:

[0031] The resistance value collected by the frost water sensor can effectively determine the frosting condition on the evaporator, so that the defrosting mode can be turned on when the frosting condition reaches the defrosting condition. After turning on the defrosting mode, the refrigeration defrosting system is controlled to form a refrigeration cycle, and the evaporator fan is controlled to be turned on and the damper is opened, so that the refrigeration compartment can be quickly refrigerated. Hot gas defrosting after refrigeration can effectively reduce the impact of the hot gas defrosting temperature rise on the temperature of the refrigeration compartment, which can prevent the defrosting from causing the indoor temperature of the refrigeration compartment to rise, and improve the quality of food storage. After entering the hot gas defrosting, the evaporator bin can be isolated from the refrigeration compartment by controlling the damper to close, so as to reduce the heat exchange between the evaporator bin and the refrigeration compartment, and further reduce the temperature rise of the refrigeration compartment. By controlling the evaporator fan to stop, it is possible to avoid the increase of wind pressure and the leakage of high temperature heat from the evaporator bin to the refrigeration compartment, which will cause the temperature of the refrigeration compartment to rise.

[0032] In one embodiment of the present application, judging whether to turn on the defrost mode according to the resistance value collected by the frost water sensor includes:

[0033] When it is detected that the resistance value collected by the frost water sensor is greater than or equal to the first set resistance value, the defrost mode is turned on;

[0034] If the resistance value collected by the frost water sensor is less than the first set resistance value, the defrost mode is not turned on.

[0035] The above technical solution has the following advantages or beneficial effects:

[0036] According to the resistance value collected by the frost water sensor, the frosting condition on the evaporator can be effectively determined. Specifically, when the resistance value collected by the frost water sensor is greater than or equal to the first set resistance value, it means that the frosting condition on the evaporator has reached the defrosting condition. At this time, it is necessary to control the defrosting mode to be turned on. On the contrary, if the resistance value collected by the frost water sensor is less than the first set resistance value, it means that the frosting condition on the evaporator has not yet reached the defrosting condition. In this case, the defrosting mode will not be turned on, which can prevent the evaporator from being frosted but very thin and does not need to be defrosted, but the defrosting is turned on, which can effectively reduce energy consumption.

[0037] In one embodiment of the present application, after defrosting, the method further includes:

[0038] When it is detected that the resistance value collected by the frost water sensor is greater than the second set resistance value but less than the third set resistance value, the evaporation fan is controlled to switch to the on state to air dry the evaporator, wherein the third set resistance value is less than or equal to the first set resistance value;

[0039] When it is detected that the resistance value collected by the frost water sensor is less than or equal to the second set resistance value, the refrigeration solenoid valve is controlled to switch to the on state, the defrost solenoid valve is switched to the off state, and the damper is controlled to remain in the closed state to cool the evaporator bin.

[0040] The above technical solution has the following advantages or beneficial effects:

[0041] After defrosting, the frost on the evaporator will gradually decrease, and the resistance value collected by the frost water sensor will also gradually decrease. When the resistance value collected by the frost water sensor is greater than the second set resistance value but less than the third set resistance value, it means that the frost on the evaporator has melted and entered a dripping state. At this time, by controlling the evaporation fan to turn on, the evaporator can be dried faster, thereby improving the defrosting efficiency and shortening the defrosting cycle. When the resistance value collected by the frost water sensor is less than or equal to the second set resistance value, it means that the defrosting water on the surface of the evaporator has basically dripped or been blown dry. At this time, by controlling the refrigeration defrosting system to form a refrigeration cycle, the evaporator bin can be cooled and cooled. At this time, the temperature of the evaporator bin is still higher than the temperature of the refrigeration compartment. By controlling the damper to remain closed, the heat of the evaporator bin can be prevented from being transferred to the refrigeration compartment, reducing the temperature rise of the refrigeration compartment.

[0042] In one embodiment of the present application, the refrigeration device further includes a second temperature sensor, which is disposed on the evaporator and is used to collect the evaporator temperature; after refrigerating the evaporator bin, the method further includes:

[0043] When it is detected that the temperature in the evaporator bin collected by the second temperature sensor is less than or equal to the refrigeration compartment temperature collected by the first temperature sensor, the damper is controlled to switch to an open state to cool the refrigeration compartment.

[0044] The above technical solution has the following advantages or beneficial effects:

[0045] After the evaporator bin is cooled, the temperature inside the evaporator bin will gradually decrease. When the temperature inside the evaporator bin decreases to less than or equal to the temperature of the refrigeration compartment, the damper is controlled to open to cool the refrigeration compartment. That is, the damper is controlled to open only when it is detected that the temperature inside the evaporator bin decreases to the same temperature as the refrigeration compartment, which can effectively prevent the temperature of the refrigeration compartment from rising again.

[0046] In one embodiment of the present application, the preset temperature is determined based on a set temperature in a cooling mode, a shutdown point temperature, and an allowable temperature fluctuation range.

[0047] The above technical solution has the following advantages or beneficial effects:

[0048] The preset temperature is determined based on the set temperature in the refrigeration mode, the shutdown point temperature and the allowable temperature fluctuation range, so that the temperature of the refrigeration room can be reduced to the lowest value within the allowable fluctuation range before hot gas defrosting, so as to reduce the temperature rise range of the indoor temperature of the refrigeration room caused by hot gas defrosting.

[0049] To achieve the above objectives, the present application provides a refrigeration device, comprising:

[0050] The box body, which serves as the supporting structure of the refrigeration device, is equipped with an evaporator bin and several refrigeration compartments;

[0051] The refrigeration and defrosting system described in any embodiment of the present application is arranged in the box, and the refrigeration and defrosting system includes an evaporator, and the evaporator is arranged in the evaporator bin, and the evaporator bin has an air outlet and an air inlet, and the air outlet and the air inlet are both provided with dampers, and the evaporator bin and the refrigeration compartment are isolated or connected by the dampers;

[0052] an evaporating fan, arranged in the evaporator bin, for driving air from the evaporator bin into the refrigerating compartment;

[0053] A frost water sensor is arranged on the surface of the evaporator and is used to detect the frosting condition of the evaporator;

[0054] A first temperature sensor is disposed in the refrigeration room and is used to collect the refrigeration room temperature in the refrigeration room;

[0055] A controller is electrically connected to the refrigeration solenoid valve, the defrost solenoid valve, the evaporating fan, the damper, the frost water sensor and the first temperature sensor in the refrigeration and defrost system, and the controller is used to execute the defrost control method described in any embodiment of the present application.

[0056] The above technical solution has the following advantages or beneficial effects:

[0057] Since the refrigeration device includes the refrigeration and defrosting system described in any embodiment of the present application, it is possible to switch between defrosting and refrigeration, and achieve an efficient and energy-saving hot gas defrosting effect. At the same time, the defrosting cycle and the refrigeration cycle share the evaporator, the refrigeration return air heat exchange device, the defrosting return air heat exchange device, the liquid-gas separator and the compressor, which can reduce the layout of components, making the system structure simple and low in cost. The controller of the refrigeration device can execute the defrosting control method described in any embodiment of the present application, that is, the resistance value collected by the frost water sensor can be used to effectively determine the frosting condition on the evaporator, so that the defrosting mode can be turned on when the frosting condition reaches the defrosting condition. After turning on the defrosting mode, the refrigeration cycle is formed by first controlling the refrigeration and defrosting system, and the evaporation fan is controlled to be turned on and the air door is opened, so that the refrigeration room can be quickly refrigerated. After refrigeration, hot gas defrosting is performed, which can effectively reduce the influence of the hot gas defrosting temperature rise on the temperature of the refrigeration room, and can prevent the indoor temperature of the refrigeration room from rising due to defrosting, thereby improving the quality of food storage. After entering the hot gas defrost, the evaporator bin and the refrigeration compartment can be isolated by controlling the damper to close, thereby reducing the heat exchange between the evaporator bin and the refrigeration compartment, and further reducing the temperature rise in the refrigeration compartment. By controlling the evaporation fan to stop, it is possible to avoid the increase of wind pressure and the leakage of high temperature heat from the evaporator bin to the refrigeration compartment, which will cause the temperature rise in the refrigeration compartment.

[0058] In one embodiment of the present application, the refrigeration device further includes a second temperature sensor, which is disposed in the evaporator bin and is used to collect the temperature in the evaporator bin, and the second temperature sensor is electrically connected to the controller.

[0059] The above technical solution has the following advantages or beneficial effects:

[0060] By arranging a second temperature sensor in the evaporator bin and electrically connecting the second temperature sensor to the controller, after the evaporator bin is refrigerated, the damper can be controlled to open only when it is detected that the temperature in the evaporator bin is less than or equal to the temperature of the refrigeration compartment, which can effectively prevent the temperature of the refrigeration compartment from rising. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a front perspective schematic diagram of a refrigeration device according to an embodiment of the present application.

[0062] Figure 2 for Figure 1 A cross-sectional view of .

[0063] Figure 3 It is a structural schematic diagram of a refrigeration device according to an embodiment of the present application.

[0064] Figure 4 It is a structural schematic diagram of a refrigeration and defrosting system provided in one embodiment of the present application.

[0065] Figure 5 It is a structural schematic diagram of a refrigeration cycle loop provided in one embodiment of the present application.

[0066] Figure 6 It is a structural schematic diagram of a defrost circulation loop provided in one embodiment of the present application.

[0067] Figure 7 It is a step flow chart of a defrost control method provided in one embodiment of the present application.

[0068] Figure 8 It is a flowchart of steps performed after defrosting provided by an embodiment of the present application.

[0069] Fig. 9 It is a flow chart of a defrost control method provided in one embodiment of the present application.

[0070] Reference numerals:

[0071] Box body 1, refrigerating chamber 11, freezing chamber 12, box door 13, compressor compartment 14, evaporator compartment 15, evaporating fan 151, air outlet 152, air inlet 153, air door 154;

[0072] Compressor 21, refrigeration solenoid valve 22, defrost solenoid valve 23, condensation heat exchange device 24, refrigeration capillary 25, defrost capillary 26, evaporator 27, refrigeration return air heat exchange device 28, defrost return air heat exchange device 29, liquid-gas separator 20. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0074] It should be noted that, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first", "second", etc. in the specification, claims and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0075] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0076] Refrigerators have become an indispensable household appliance in people's daily lives. At present, refrigerator defrosting generally uses electric heating to defrost the evaporator. Equipment using electric heating to defrost has the following disadvantages in application:

[0077] 1. High energy consumption;

[0078] 2. The electric heating tube is inserted into the middle or lower part of the evaporator, the heating temperature of the entire evaporator is uneven, and the defrosting is not thorough;

[0079] 3. The structure is complex and the cost is high, and the risk of electric leakage of the electric heating tube is high.

[0080] Based on this, the embodiment of the present application proposes a refrigeration and defrosting system, which can switch between refrigeration and defrosting to achieve an efficient and energy-saving hot gas defrosting effect, and the system structure is simple and the cost is low.

[0081] The refrigeration device of the embodiment of the present application may be a refrigeration cabinet such as a freezer, a refrigerator, a living room bar cabinet, etc. The following takes a refrigerator as an example to describe in detail the technical solution for improving the refrigeration device of the embodiment of the present application.

[0082] Figure 1 It is a front perspective schematic diagram of a refrigeration device according to an embodiment of the present application. Figure 2 for Figure 1 A cross-sectional view of . Figure 3 It is a structural schematic diagram of a refrigeration device according to an embodiment of the present application.

[0083] See also Figure 1 to Figure 2 As shown, the refrigerator provided in the embodiment of the present application may include a box body 1. The box body 1 may adopt a hollow structure such as a rectangular parallelepiped. The box body 1 forms an outer shell of the refrigerator. It should be noted that the box body 1 may also adopt a hollow shell structure of other shapes.

[0084] See also Figure 2 As shown, in some embodiments, the box body 1 may be provided with a plurality of refrigeration compartments, and the refrigeration compartments may include a refrigeration compartment 11 and / or a freezer compartment 12. The refrigeration compartment 11 and the freezer compartment 12 may be configured as a plurality of storage compartments.

[0085] See also Figure 2 As shown, in some embodiments, the refrigerator compartment 11 and the freezer compartment 12 can be used as independent storage spaces to meet different refrigeration requirements such as freezing and refrigeration according to different types of food, and store items that need to be refrigerated or frozen. The refrigerator compartment 11 and the freezer compartment 12 can be arranged in a vertical partition or a horizontal partition.

[0086] See also Figure 2 As shown, in some embodiments, the refrigerator may include a cabinet. A refrigerating chamber 11 and a freezing chamber 12 may be formed in the cabinet.

[0087] See also Figure 2 As shown, in some embodiments, the refrigerator may include a door 13. The door 13 may be hinged to the front side of the cabinet 1 to open and close the refrigerating chamber 11 and the freezing chamber 12.

[0088] It should be noted that a plurality of doors 13 may be provided. The doors 13 may be provided in a one-to-one correspondence with the refrigerating chamber 11 and the freezing chamber 12. One refrigerating chamber 11 may be provided with one or more doors 13, and one freezing chamber may also be provided with one or more doors 13.

[0089] In some embodiments, see Figure 2 A compressor compartment 14 may be provided inside the housing 1. A compressor 21 may be provided inside the compressor compartment 14. The compressor compartment 14 may be provided at the bottom area inside the housing 1. The compressor compartment 14 may be located at the rear side and below the freezing chamber 12.

[0090] It should be noted that, in some other embodiments, the compressor compartment 14 may also be disposed at other locations such as the top or side of the housing 1 .

[0091] In some embodiments, see Figure 3 The cabinet 1 may be provided with an evaporator bin 15 inside, in which an evaporator 27 and an evaporation fan 151 are provided, and a cold air flow for refrigeration is stored in the evaporator bin 15. Usually, the evaporator bin 15 is located at the rear side of the freezing chamber 12 (the rear side refers to the side of the freezing chamber 15 opposite to the freezing chamber door). The evaporator bin 15 has a plurality of air outlets 152 and a plurality of air inlets 153, each of the air outlets 152 and each of the air inlets 153 is provided with a damper 154, and the evaporator bin 15 is isolated or connected with the refrigerating chamber 11 through the damper 154, and the evaporator bin 15 is also isolated or connected with the freezing chamber 12 through the damper 154. The cold air flow derived from the evaporator bin 15 is transported to the freezing chamber 15 through a freezing air duct provided between the evaporator bin 15 and the freezing chamber 15 to refrigerate the freezing chamber 15, the air inlet of the freezing air duct is communicated with the air outlet 152 of the evaporator bin 15, and the air outlet of the freezing air duct is communicated with the air inlet 153 of the evaporator bin 15. The cold air flow derived from the evaporator bin 15 is transported to the refrigerating chamber 11 through a refrigerating air duct to refrigerate the refrigerating chamber 11, the air inlet of the refrigerating air duct is communicated with the air outlet 152 of the evaporator bin 15, and the air outlet of the refrigerating air duct is communicated with the air inlet 153 of the evaporator bin 15.

[0092] Reference Figure 4 In some embodiments, the refrigeration device also includes a refrigeration and defrosting system. Figure 4 Schematic diagram of the structure of the refrigeration and defrosting system provided by an embodiment of the present application. Figure 4As shown, the refrigeration and defrost system includes a compressor 21, a refrigeration solenoid valve 22, a defrost solenoid valve 23, a condensation heat exchange device 24, a refrigeration capillary 25, a defrost capillary 26, an evaporator 27, a refrigeration return air heat exchange device 28, a defrost return air heat exchange device 29 and a liquid-gas separator 20. Among them, the first end of the compressor 21 is connected to the first end of the refrigeration solenoid valve 22, the second end of the refrigeration solenoid valve 22 is connected to the first end of the condensation heat exchange device 24, the second end of the condensation heat exchange device 24 is connected to the first end of the refrigeration return air heat exchange device 28, the second end of the refrigeration return air heat exchange device 28 is connected to the first end of the refrigeration capillary 25, the second end of the refrigeration capillary 25 is connected to the first end of the evaporator 27, the second end of the evaporator 27 is connected to the third end of the refrigeration return air heat exchange device 28, the fourth end of the refrigeration return air heat exchange device 28 is connected to the first end of the defrost return air heat exchange device 29, the second end of the defrost return air heat exchange device 29 is connected to the first end of the liquid-gas separator 20, and the second end of the liquid-gas separator 20 is connected to the second end of the compressor 21. The first end of the compressor 21 is also connected to the first end of the defrost solenoid valve 23, the second end of the defrost solenoid valve 23 is connected to the third end of the defrost return air heat exchange device 29, the fourth end of the defrost return air heat exchange device 29 is connected to the first end of the defrost capillary 26, and the second end of the defrost capillary 26 is connected to the first end of the evaporator 27.

[0093] In the embodiment of the present application, the refrigeration defrost system includes a defrost cycle and a refrigeration cycle. The defrost cycle and the refrigeration cycle share an evaporator 27, a refrigeration return air heat exchange device 28, a defrost return air heat exchange device 29, a liquid-gas separator 20 and a compressor 21, which can reduce the layout of components and make the system structure simple and low in cost. In addition, by setting the liquid-gas separator 20, the compressor liquid hammer can be effectively prevented. By controlling the opening and closing of the defrost solenoid valve 23 and the refrigeration solenoid valve 22, the defrost and refrigeration can be switched to achieve an efficient and energy-saving hot gas defrosting effect.

[0094] Reference Figure 5 , Figure 5 1 is a schematic diagram of the structure of a refrigeration cycle provided by an embodiment of the present application. The refrigeration and defrosting system includes a refrigeration cycle, which includes a compressor 21, a refrigeration solenoid valve 22, a condensation heat exchange device 24, a refrigeration return air heat exchange device 28, a refrigeration capillary 25, an evaporator 27, a refrigeration return air heat exchange device 28, a defrosting return air heat exchange device 29, a liquid-gas separator 20 and a compressor 21, which are sequentially connected to form a loop.

[0095] Specifically, in the refrigeration cycle, the refrigeration solenoid valve 22 is turned on and the defrost solenoid valve 23 is turned off. The compressor 21 discharges high-temperature gaseous refrigerant, which enters the condensation heat exchange device 24 for heat exchange through the refrigeration solenoid valve 22, enters the refrigeration return air heat exchange device 28 for heat exchange and cooling, and then throttles through the refrigeration capillary 25 to become a low-temperature liquid. The low-temperature liquid enters the evaporator 27 to evaporate and exchanges heat with the evaporator bin 15 to achieve refrigeration and cooling of the evaporator bin 15. Then, it is driven by the evaporation fan 151 to convect with the refrigeration compartment through the air outlet 152 and the air inlet 153 to achieve refrigeration and cooling of the refrigeration compartment. After the refrigerant exchanges heat in the evaporator 27, it exchanges heat in the refrigeration return air heat exchange device 28, and then exchanges heat in the defrost return air heat exchange device 29. After reaching the overheated state, it is finally separated by the liquid-gas separator 20 to ensure that the gaseous refrigerant flows back to the compressor. In this way, the refrigeration compartments such as the refrigerator compartment 11 and / or the freezer compartment 12 can be cooled and cooled.

[0096] In some embodiments, the refrigeration device further includes a first temperature sensor, which is arranged in the refrigeration compartment, and the first temperature sensor is used to collect the temperature of the refrigeration compartment. For example, a first temperature sensor can be arranged in the refrigeration compartment 11 to collect the temperature in the refrigeration compartment 11. A first temperature sensor can also be arranged in the freezer compartment 12 to collect the temperature in the freezer compartment 12. Therefore, based on the temperature of the refrigeration compartment collected by the first temperature sensor, it is possible to control whether the refrigeration and defrosting system forms a refrigeration cycle. Specifically, when it is detected that the temperature of the refrigeration compartment collected by the first temperature sensor is greater than or equal to the first set temperature, the refrigeration solenoid valve 22 is controlled to be turned on, and the defrosting solenoid valve 23 is disconnected, so that the refrigeration and defrosting system forms a refrigeration cycle, and the compressor 21 is controlled to start, and the evaporating fan 151 is turned on to quickly refrigerate and cool the refrigeration compartment. When it is detected that the temperature of the refrigeration compartment collected by the first temperature sensor is less than or equal to the second set temperature, the refrigeration solenoid valve 22 is controlled to be disconnected, the defrosting solenoid valve 23 is disconnected, and the compressor 21 is controlled to be stopped, and the evaporating fan 151 is stopped to stop refrigerating the refrigeration compartment. The second set temperature is lower than the first set temperature.

[0097] It should be noted that the first set temperature can be determined based on the set temperature of the refrigeration compartment and the temperature fluctuation range allowed, and the first set temperature is equal to the set temperature plus the absolute value of the temperature fluctuation range allowed. The second set temperature can be determined based on the set temperature of the refrigeration compartment and the temperature fluctuation range allowed, and the second set temperature is equal to the set temperature minus the absolute value of the temperature fluctuation range allowed.

[0098] In some embodiments, the refrigeration device further includes a second temperature sensor, which is disposed in the evaporator bin 15 and is used to collect the temperature in the evaporator bin 15. During the defrosting process, the damper 154 is first closed to isolate the evaporator bin 15 from the refrigeration compartment, reduce the heat generated by the hot gas defrosting to be transferred to the refrigeration compartment, and reduce the temperature rise in the refrigeration compartment. When the frost on the evaporator 27 is detected to be melted, the refrigeration defrosting system needs to be controlled to form a refrigeration cycle to refrigerate and cool the evaporator bin 15. At this time, the temperature collected by the second temperature sensor will gradually decrease. When it is detected that the temperature in the evaporator bin 15 collected by the second temperature sensor is less than or equal to the temperature of the refrigeration compartment collected by the first temperature sensor, the damper 154 is controlled to open, which can effectively prevent the temperature of the refrigeration compartment from rising during the defrosting process.

[0099] It should be noted that when refrigeration or defrosting is performed, the compressor 21 is in the on state, and when neither refrigeration nor defrosting is required, the compressor 21 is turned off.

[0100] Reference Figure 6 , Figure 6 1 is a schematic diagram of the structure of a defrost cycle provided by an embodiment of the present application. The refrigeration defrost system includes a defrost cycle, and the defrost cycle includes a compressor 21, a defrost solenoid valve 23, a defrost return air heat exchange device 29, a defrost capillary 26, an evaporator 27, a refrigeration return air heat exchange device 28, a defrost return air heat exchange device 29, a liquid-gas separator 20 and a compressor 21, which are sequentially connected to form a loop.

[0101] Specifically, in the defrost cycle, the refrigeration solenoid valve 22 is disconnected and the defrost solenoid valve 23 is turned on. The compressor 21 discharges high-temperature gaseous refrigerant, which enters the defrost return air heat exchange device 29 through the defrost solenoid valve 23 to store heat, and then throttles through the defrost capillary 26. The high-temperature refrigerant continues to enter the evaporator 27 and efficiently exchanges heat with the frost on its surface for defrosting. After rapid and efficient defrosting, the refrigerant flowing out of the evaporator 27 reaches an overheated state after sufficient heat exchange with the refrigeration return air heat exchange device 28 and the defrost return air heat exchange device 29, and is finally separated by the liquid-gas separator 20 to ensure that the gaseous refrigerant returns to the compressor 21. In this cycle, the frost on the evaporator 27 can be defrosted.

[0102] In some embodiments, the refrigeration device further includes a frost water sensor, which is arranged on the surface of the evaporator 27 and is used to detect the frosting condition of the evaporator 27. A gate electrode is used above the frost water sensor, and the conductivity of water is used to determine whether water falls on the sensing area. When there is water on the sensing area, the resistance between the two electrodes will change. The resistance value can be used to determine whether there is condensation, frost, or ice on the surface of the evaporator, as well as the amount of frost water. Specifically, when the resistance value collected by the frost water sensor is greater than or equal to the first set resistance value R1, it means that the amount of frost on the surface of the evaporator 27 has reached the defrosting condition, and the defrosting mode is entered at this time. When the resistance value collected by the frost water sensor is less than the first set resistance value, it means that the amount of frost on the surface of the evaporator 27 has not reached the defrosting condition, and there is no need to enter the defrosting mode.

[0103] Reference Figure 7 , Figure 7 It is a step flow chart of a defrost control method provided in an embodiment of the present application, which is executed by a refrigeration device provided in an embodiment of the present application, including but not limited to steps S710 to S730.

[0104] Step S710, judging whether to turn on the defrost mode according to the resistance value collected by the frost water sensor;

[0105] Step S720, when the defrost mode is turned on, the refrigeration solenoid valve in the refrigeration and defrost system is controlled to be in the on state, the defrost solenoid valve is in the off state, and the evaporation fan is controlled to remain in the on state, and the damper is in the open state, so as to refrigerate the refrigeration compartment;

[0106] Step S730, when it is detected that the refrigeration compartment temperature collected by the first temperature sensor is less than or equal to the preset temperature, or the refrigeration time after the defrost mode is turned on is greater than or equal to the preset time, the refrigeration solenoid valve is controlled to switch to the disconnected state, the defrost solenoid valve is switched to the on state, and the evaporating fan is controlled to switch to the stopped state, and the damper is switched to the closed state to perform defrosting.

[0107] In the embodiment of the present application, the amount of frost on the evaporator 27 can be determined according to the resistance value collected by the frost water sensor arranged on the surface of the evaporator. When the resistance value collected by the frost water sensor is greater than or equal to the first set resistance value, it means that the amount of frost on the evaporator 27 has reached the defrosting condition. At this time, the refrigeration device can be controlled to start the defrosting mode. If the resistance value collected by the frost water sensor is less than the first set resistance value, it means that the amount of frost on the evaporator 27 has not reached the defrosting condition, and the defrosting mode is not turned on. After the defrosting mode is turned on, regardless of whether the current state is refrigeration or refrigeration stop, the refrigeration solenoid valve 22 is first controlled to be in the on state and the defrosting solenoid valve 23 is in the off state, so as to control the refrigeration defrosting system to form a refrigeration cycle. And the evaporation fan 151 is controlled to be turned on and the damper 154 is opened, so as to quickly refrigerate the refrigeration compartment. Until it is detected that the temperature of the refrigeration compartment collected by the first temperature sensor is less than or equal to the preset temperature, the refrigeration defrosting system is controlled to switch to form a defrosting cycle to perform hot gas defrosting. Among them, the preset temperature is determined based on the set temperature in the refrigeration mode, the shutdown point temperature and the temperature allowable fluctuation range. Specifically, the preset temperature is equal to the set temperature in the refrigeration mode minus the shutdown point temperature plus the absolute value of the temperature allowable fluctuation range. Alternatively, in the case of severe frosting of the evaporator 27, the refrigeration efficiency is low, and it is possible that the preset temperature cannot be reduced by refrigeration, then the standby time timer starts timing from the start of the defrost mode, and when the refrigeration time after the defrost mode is turned on is greater than or equal to the preset time, the refrigeration and defrost system is controlled to switch to form a defrost cycle loop to perform hot gas defrosting. After the defrost mode is turned on, the refrigeration compartment is first cooled to a preset temperature or the refrigeration time is greater than or equal to the preset time before hot gas defrosting is performed, which can ensure that the temperature is reduced to the minimum value within the allowable fluctuation range, so as to reduce the temperature rise range caused by high-temperature defrosting. That is, the indoor temperature rise in the refrigeration compartment caused by defrosting can be reduced, and the food storage quality can be improved. After entering the hot gas defrost, the evaporator bin 15 can be isolated from the refrigeration compartment by controlling the damper 154 to be closed, so as to reduce the cold and heat exchange between the evaporator bin 15 and the refrigeration compartment, and further reduce the temperature rise in the refrigeration compartment. By controlling the evaporation fan 151 to stop, it is possible to avoid an increase in wind pressure, leakage of high-temperature heat from the evaporator bin 15 into the refrigeration compartment, and a rise in the temperature of the refrigeration compartment.

[0108] Reference Figure 8 , Figure 8 It is a flowchart of steps performed after defrosting provided by an embodiment of the present application, which is performed by the refrigeration device provided by the embodiment of the present application, including but not limited to steps S810 to S830.

[0109] Step S810, when it is detected that the resistance value collected by the frost water sensor is greater than the second set resistance value but less than the third set resistance value, the evaporation fan is controlled to switch to the on state to air dry the evaporator, wherein the third set resistance value is less than or equal to the first set resistance value;

[0110] Step S820, when it is detected that the resistance value collected by the frost water sensor is less than or equal to the second set resistance value, the refrigeration solenoid valve is controlled to switch to the on state, the defrost solenoid valve is switched to the off state, and the damper is controlled to remain in the closed state, so as to cool the evaporator bin;

[0111] Step S830: when it is detected that the temperature in the evaporator compartment collected by the second temperature sensor is less than or equal to the temperature of the refrigerating compartment collected by the first temperature sensor, the damper is controlled to be switched to an open state to cool the refrigerating compartment.

[0112] In the embodiment of the present application, after defrosting, the frost on the evaporator 27 will gradually decrease, and the resistance value collected by the frost water sensor will also gradually decrease. When the resistance value collected by the frost water sensor is greater than the second set resistance value but less than the third set resistance value, it means that the frost on the evaporator 27 has melted and entered a dripping state. At this time, by controlling the evaporation fan 151 to turn on, the evaporator 27 can be dried up quickly, thereby improving the defrosting efficiency and shortening the defrosting cycle. When the resistance value collected by the frost water sensor is less than or equal to the second set resistance value, it means that the defrosting water on the surface of the evaporator 27 has basically dripped or been blown dry. At this time, the refrigeration solenoid valve 22 is controlled to switch to the on state, and the defrost solenoid valve 23 is switched to the off state, that is, the refrigeration defrosting system is controlled to form a refrigeration cycle, which can cool the evaporator bin 15. At this time, the temperature of the evaporator bin 15 is still higher than the temperature of the refrigeration compartment. By controlling the damper 154 to remain closed, the heat of the evaporator bin 15 can be prevented from being transferred to the refrigeration compartment, thereby reducing the temperature rise of the refrigeration compartment. After the evaporator bin 15 is cooled and cooled, the temperature in the evaporator bin 15 will gradually decrease. When the temperature in the evaporator bin 15 collected by the second temperature sensor decreases to less than or equal to the temperature of the refrigeration compartment collected by the first temperature sensor, the damper 154 is controlled to open to refrigerate the refrigeration compartment. That is, the damper 154 is controlled to open only when it is detected that the temperature in the evaporator bin 15 decreases to less than or equal to the temperature of the refrigeration compartment, which can effectively prevent the temperature of the refrigeration compartment from rising again.

[0113] Reference Fig. 9 , Fig. 9 It is a flow chart of a defrost control method provided in an embodiment of the present application, which is executed by a refrigeration device provided in an embodiment of the present application, including but not limited to steps S910 to S9130.

[0114] Step S910, determining whether the resistance value collected by the frost water sensor is greater than or equal to a first set resistance value;

[0115] Step S920, when the resistance value collected by the frost water sensor is greater than or equal to the first set resistance value, the defrost mode is turned on;

[0116] Step S930, when the resistance value collected by the frost water sensor is less than the first set resistance value, the defrost mode is not turned on;

[0117] Step S940, when the defrost mode is turned on, the refrigeration solenoid valve is controlled to be in the on state, the defrost solenoid valve is in the off state, and the evaporation fan is controlled to remain in the on state, and the damper is in the open state, so as to cool the refrigeration compartment;

[0118] Step S950, detecting whether the refrigeration compartment temperature acquired by the first temperature sensor is less than or equal to a preset temperature;

[0119] Step S960, or, determining whether the refrigeration time after the defrost mode is turned on is greater than or equal to a preset time;

[0120] Step S970, when it is detected that the temperature of the refrigeration compartment is less than or equal to the preset temperature, or the refrigeration time after the defrost mode is turned on is greater than or equal to the preset time, the refrigeration solenoid valve is controlled to switch to the disconnected state, the defrost solenoid valve is controlled to switch to the on state, and the evaporation fan is controlled to switch to the stopped state, and the damper is controlled to switch to the closed state to perform defrosting;

[0121] Step S980, detecting whether the resistance value collected by the frost water sensor is greater than the second set resistance value but less than the third set resistance value;

[0122] Step S990, when it is detected that the resistance value collected by the frost water sensor is greater than the second set resistance value but less than the third set resistance value, the evaporation fan is controlled to switch to an on state to air dry the evaporator;

[0123] Step S9100, detecting whether the resistance value collected by the frost water sensor is less than or equal to a second set resistance value;

[0124] Step S9110, when it is detected that the resistance value collected by the frost water sensor is less than or equal to the second set resistance value, the refrigeration solenoid valve is controlled to switch to the on state, the defrost solenoid valve is switched to the off state, and the damper is controlled to remain in the closed state, so as to cool the evaporator bin;

[0125] Step S9120, detecting whether the temperature in the evaporator bin collected by the second temperature sensor is less than or equal to the refrigeration compartment temperature collected by the first temperature sensor;

[0126] Step S9130, when it is detected that the temperature in the evaporator compartment is equal to the temperature of the refrigeration compartment, the damper is controlled to switch to an open state to cool the refrigeration compartment.

[0127] In the embodiment of the present application, the frosting condition on the evaporator 27 can be effectively determined by the resistance value collected by the frost water sensor, so that the defrosting mode can be turned on when the frosting condition reaches the defrosting condition. After the defrosting mode is turned on, the refrigeration defrosting system is controlled to form a refrigeration cycle, and the evaporation fan 151 is controlled to be turned on and the damper 154 is opened, so that the refrigeration compartment can be quickly refrigerated. After refrigeration, hot gas defrosting is performed, which can effectively reduce the impact of the hot gas defrosting temperature rise on the temperature of the refrigeration compartment, and can prevent the defrosting from causing the temperature in the refrigeration compartment to rise, thereby improving the quality of food storage. After entering the hot gas defrosting, the evaporator bin 15 can be isolated from the refrigeration compartment by controlling the damper 154 to be closed, so as to reduce the heat exchange between the evaporator bin 15 and the refrigeration compartment, and further reduce the temperature rise of the refrigeration compartment. By controlling the evaporation fan 151 to stop, it is possible to avoid the increase of wind pressure, and the high temperature heat of the evaporator bin 15 leaking to the refrigeration compartment to cause the temperature of the refrigeration compartment to rise. After defrosting, the frost on the evaporator will gradually decrease, and the resistance value collected by the frost water sensor will also gradually decrease. When the resistance value collected by the frost water sensor is greater than the second set resistance value but less than the third set resistance value, it means that the frost on the evaporator has melted and entered a dripping state. At this time, by controlling the evaporation fan to turn on, the evaporator can be dried quickly, thereby improving the defrosting efficiency and shortening the defrosting cycle. When the resistance value collected by the frost water sensor is less than or equal to the second set resistance value, it means that the defrosting water on the surface of the evaporator has basically dripped or been blown dry. At this time, by controlling the refrigeration defrosting system to form a refrigeration cycle, the evaporator bin can be refrigerated and cooled. At this time, the temperature of the evaporator bin is still higher than the temperature of the refrigeration compartment. By controlling the damper to remain closed, the heat of the evaporator bin can be prevented from being transferred to the refrigeration compartment, reducing the temperature rise of the refrigeration compartment. After the evaporator bin is refrigerated, the temperature in the evaporator bin will gradually decrease. When the temperature in the evaporator bin drops to less than or equal to the temperature of the refrigeration compartment, the damper is controlled to open to refrigerate the refrigeration compartment. That is, the damper is controlled to open only when it is detected that the temperature in the evaporator bin drops to the same level as the temperature in the refrigeration compartment, which can effectively prevent the temperature in the refrigeration compartment from rising again.

[0128] The embodiments described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0129] Those skilled in the art will appreciate that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0130] Those skilled in the art will appreciate that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices may be implemented as software, firmware, hardware, or a suitable combination thereof.

[0131] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0132] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0133] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A refrigeration and defrosting system, characterized in that: It includes a compressor, a refrigeration solenoid valve, a defrost solenoid valve, a condensation heat exchange device, a refrigeration capillary tube, a defrost capillary tube, an evaporator, a refrigeration return air heat exchange device, a defrost return air heat exchange device and a liquid-gas separator; The first end of the compressor is communicated with the first end of the refrigeration solenoid valve, the second end of the refrigeration solenoid valve is communicated with the first end of the condensation heat exchange device, the second end of the condensation heat exchange device is communicated with the first end of the refrigeration return air heat exchange device, the second end of the refrigeration return air heat exchange device is communicated with the first end of the refrigeration capillary tube, the second end of the refrigeration capillary tube is communicated with the first end of the evaporator, the second end of the evaporator is communicated with the third end of the refrigeration return air heat exchange device, the fourth end of the refrigeration return air heat exchange device is communicated with the first end of the defrost return air heat exchange device, the second end of the defrost return air heat exchange device is communicated with the first end of the liquid-gas separator, and the second end of the liquid-gas separator is communicated with the second end of the compressor; The first end of the compressor is also connected to the first end of the defrost solenoid valve, the second end of the defrost solenoid valve is connected to the third end of the defrost return air heat exchange device, the fourth end of the defrost return air heat exchange device is connected to the first end of the defrost capillary, and the second end of the defrost capillary is connected to the first end of the evaporator.

2. The system according to claim 1, characterized in that The system includes a refrigeration cycle circuit, which includes the compressor, the refrigeration solenoid valve, the condensation heat exchange device, the refrigeration return air heat exchange device, the refrigeration capillary tube, the evaporator, the refrigeration return air heat exchange device, the defrost return air heat exchange device, the liquid-gas separator and the compressor, which are connected in sequence to form a loop.

3. The method according to claim 2, characterized in that The system also includes a defrost circulation loop, which includes the compressor, the defrost solenoid valve, the defrost return air heat exchange device, the defrost capillary, the evaporator, the refrigeration return air heat exchange device, the defrost return air heat exchange device, the liquid-gas separator and the compressor, which are connected in sequence to form a loop.

4. A defrost control method for a refrigeration device, characterized in that: The refrigeration device comprises: The box body, which serves as the supporting structure of the refrigeration device, is equipped with an evaporator bin and several refrigeration compartments; The refrigeration and defrosting system according to any one of claims 1 to 3, which is arranged in the box, the refrigeration and defrosting system comprises an evaporator, the evaporator is arranged in the evaporator bin, the evaporator bin has an air outlet and an air inlet, the air outlet and the air inlet are both provided with dampers, and the evaporator bin and the refrigeration compartment are isolated or connected by the dampers; an evaporating fan, arranged in the evaporator bin, for driving air from the evaporator bin into the refrigerating compartment; A frost water sensor is arranged on the surface of the evaporator and is used to detect the frosting condition of the evaporator; A first temperature sensor is disposed in the refrigeration room and is used to collect the refrigeration room temperature in the refrigeration room; The defrost control method comprises: Determining whether to turn on the defrost mode according to the resistance value collected by the frost water sensor; When the defrost mode is turned on, the refrigeration solenoid valve in the refrigeration and defrost system is controlled to be in a conducting state, the defrost solenoid valve is in a disconnected state, and the evaporation fan is controlled to remain in an on state, and the damper is in an open state, so as to refrigerate the refrigeration compartment; When it is detected that the refrigeration compartment temperature collected by the first temperature sensor is less than or equal to the preset temperature, or the refrigeration time after the defrost mode is turned on is greater than or equal to the preset time, the refrigeration solenoid valve is controlled to switch to the disconnected state, the defrost solenoid valve is switched to the on state, the evaporating fan is controlled to switch to the stopped state, and the damper is switched to the closed state for defrosting.

5. The method according to claim 4, characterized in that The step of judging whether to start the defrost mode according to the resistance value collected by the frost water sensor includes: When it is detected that the resistance value collected by the frost water sensor is greater than or equal to the first set resistance value, the defrost mode is turned on; If the resistance value collected by the frost water sensor is less than the first set resistance value, the defrost mode is not turned on.

6. The method according to claim 5, characterized in that After defrosting, the method further comprises: When it is detected that the resistance value collected by the frost water sensor is greater than the second set resistance value but less than the third set resistance value, the evaporation fan is controlled to switch to the on state to air dry the evaporator, wherein the third set resistance value is less than or equal to the first set resistance value; When it is detected that the resistance value collected by the frost water sensor is less than or equal to the second set resistance value, the refrigeration solenoid valve is controlled to switch to the on state, the defrost solenoid valve is switched to the off state, and the damper is controlled to remain in the closed state to cool the evaporator bin.

7. The method according to claim 6, characterized in that The refrigeration device further includes a second temperature sensor, which is disposed in the evaporator bin and is used to collect the temperature in the evaporator bin; after refrigerating the evaporator bin, the method further includes: When it is detected that the temperature in the evaporator bin collected by the second temperature sensor is less than or equal to the refrigeration compartment temperature collected by the first temperature sensor, the damper is controlled to switch to an open state to cool the refrigeration compartment.

8. The method according to claim 4, characterized in that The preset temperature is determined based on a set temperature in a cooling mode, a shutdown point temperature, and an allowable temperature fluctuation range.

9. A refrigeration device, characterized in that: include: The box body, which serves as the supporting structure of the refrigeration device, is equipped with an evaporator bin and several refrigeration compartments; The refrigeration and defrosting system according to any one of claims 1 to 3, which is arranged in the box, the refrigeration and defrosting system comprises an evaporator, the evaporator is arranged in the evaporator bin, the evaporator bin has an air outlet and an air inlet, the air outlet and the air inlet are both provided with dampers, and the evaporator bin and the refrigeration compartment are isolated or connected by the dampers; an evaporating fan, arranged in the evaporator bin, for driving air from the evaporator bin into the refrigerating compartment; A frost water sensor is arranged on the surface of the evaporator and is used to detect the frosting condition of the evaporator; A first temperature sensor is disposed in the refrigeration room and is used to collect the refrigeration room temperature in the refrigeration room; A controller is electrically connected to the refrigeration solenoid valve, the defrost solenoid valve, the evaporating fan, the damper, the frost water sensor and the first temperature sensor in the refrigeration and defrost system, and the controller is used to execute the defrost control method described in any one of claims 4 to 8.

10. The refrigeration device according to claim 9, characterized in that: The refrigeration device further includes a second temperature sensor, which is disposed in the evaporator bin and is used to collect the temperature in the evaporator bin. The second temperature sensor is electrically connected to the controller.

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