Defrosting control method and refrigeration and freezing device

Abstract

The application discloses a defrosting control method and a refrigerating and freezing device. The defrosting control method is used for the refrigerating and freezing device, and comprises the following steps: in a defrosting mode, a defrosting heating element is controlled to start heating; an evaporator temperature is acquired; when the evaporator temperature reaches a defrosting fan starting temperature threshold, the defrosting fan is controlled to rotate in a first rotating direction, the first rotating direction is opposite to a second rotating direction, and the second rotating direction is a rotating direction in a refrigeration mode of a refrigeration fan; and the rotating speed of the defrosting fan is controlled according to the change of the evaporator temperature in multiple different stages of a temperature rising stage and a temperature falling stage. The method can start the defrosting fan to rotate in the first rotating direction in the defrosting process, and control the rotating speed of the defrosting fan according to the change of the evaporator temperature, so that the hot air in an evaporator cabin is inhibited from entering an air duct, and the temperature rising of a storage compartment caused by defrosting is reduced.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment technology, and in particular to a defrosting control method and a refrigeration and freezing device. Background Technology

[0002] In existing technology, during the defrosting heating process of refrigeration and freezing equipment, the temperature of the evaporator compartment gradually rises, and the hot gas in the evaporator compartment flows into the storage compartment through the air duct, causing the temperature of the storage compartment to rise as well, thus affecting the food storage life and reducing the food preservation effect. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the first objective of the present invention is to provide a defrosting control method for refrigeration and freezing devices. The method of the present invention can start the defrosting fan to rotate in a first rotation direction during the defrosting process, and control the speed of the defrosting fan according to the change of evaporator temperature, thereby suppressing the entry of hot air from the evaporator compartment into the air duct, thereby reducing the temperature rise in the storage compartment caused by defrosting.

[0004] The second objective of this invention is to provide a refrigeration and freezing device.

[0005] To achieve the above objectives, the present invention provides a defrosting control method for a refrigeration and freezing device. The refrigeration and freezing device includes an air duct formed by a front cover plate and a rear cover plate, a refrigeration and freezing device inner liner, a compressor, an evaporator, a refrigeration fan, and a defrosting heating element. The rear cover plate and the refrigeration and freezing device inner liner form an evaporator compartment. The rear cover plate has an air inlet. The evaporator is located in the evaporator compartment. The refrigeration fan is located in the air duct and positioned at the air inlet. The defrosting heating element is located within the evaporator compartment. The refrigeration and freezing device also includes a defrosting mechanism. A defrosting fan is located in the evaporator compartment and positioned at the air inlet. The defrosting control method includes: in defrosting mode, controlling the defrosting heating element to start heating; acquiring the evaporator temperature; when the evaporator temperature reaches the defrosting fan start-up temperature threshold, controlling the defrosting fan to rotate in a first rotation direction, the first rotation direction being opposite to a second rotation direction, the second rotation direction being the rotation direction of the refrigeration fan in cooling mode; and controlling the speed of the defrosting fan according to the change in the evaporator temperature in multiple different stages of heating and cooling phases.

[0006] According to the defrosting control method of the present invention, the evaporator temperature is acquired in real time during the defrosting process. When the evaporator temperature reaches the start-up temperature threshold, the defrosting fan is started to rotate in a first rotation direction. The change in evaporator temperature is divided into multiple stages, and the speed of the defrosting fan is controlled according to different stages, thereby preventing hot air from entering the air duct of the evaporator compartment, inhibiting the entry of defrosting hot air into the storage compartment, reducing the temperature rise in the storage compartment caused by defrosting, and at the same time, the unused hot air is applied to the evaporator by the defrosting fan, thereby improving the defrosting efficiency of the evaporator.

[0007] In some embodiments, the speed of the defrosting fan is controlled in multiple different stages, including a heating stage and a cooling stage, based on the change in the evaporator temperature. This includes: when the evaporator temperature is in a first heating stage, which is the stage where the evaporator temperature rises from the defrosting fan start-up temperature threshold to a first temperature threshold, controlling the speed of the defrosting fan to increase from the minimum allowable speed until the evaporator temperature reaches the first temperature threshold; wherein the speed of the defrosting fan is gradually increased in units of a first speed value, where the first speed value is the speed increase of the defrosting fan for each unit increase in evaporator temperature.

[0008] The above technical solution has the following advantages or beneficial effects: In the first heating stage, that is, the stage when the evaporator temperature rises from the start-up temperature threshold to the first temperature threshold, the evaporator defrosting has begun to generate heat. Therefore, the defrosting fan is started at the minimum allowable speed, and the speed of the defrosting fan is increased at the first speed value according to the change of evaporator temperature, so as to avoid the hot air generated by the evaporator defrosting from entering the storage compartment to the greatest extent.

[0009] In some embodiments, controlling the speed of the defrosting fan in multiple different stages, including a heating phase and a cooling phase, according to the change in the evaporator temperature, further includes: when the evaporator temperature is in the second heating phase, controlling the speed of the defrosting fan to continue to increase until the evaporator temperature reaches the maximum defrost temperature, the maximum defrost temperature being greater than the first temperature threshold; wherein the speed of the defrosting fan is gradually increased in units of a second speed value, the second speed value being the speed increase of the defrosting fan for each unit increase in the evaporator temperature, the second speed value being less than the first speed value.

[0010] The above technical solution has the following advantages or beneficial effects: In order to fully defrost the evaporator, the maximum defrost temperature is greater than 0°C. When the evaporator temperature reaches the maximum defrost temperature, the heat generated by the defrost of the evaporator is the highest. At this time, the speed of the defrost fan is increased by the second speed value to ensure that the hot air generated by the defrost of the evaporator cannot enter the storage room.

[0011] In some embodiments, the change in evaporator temperature further includes a maintenance phase, which is located between the first heating phase and the second heating phase in time; during the second heating phase, the speed of the defrosting fan begins to increase from the speed of the defrosting fan at the end of the maintenance phase; the defrosting control method further includes: entering the maintenance phase when the evaporator temperature reaches the first temperature threshold; and controlling the defrosting fan to maintain a constant speed when the evaporator temperature is in the maintenance phase.

[0012] The above technical solution has the following advantages or beneficial effects: During the maintenance phase, the evaporator temperature remains constant and the defrosting heat remains constant. Therefore, the defrosting fan maintains a constant speed, ensuring that the defrosting heat cannot enter the storage compartment while avoiding excessive energy waste caused by excessively high defrosting fan speed, thus preventing excessive power consumption of the refrigeration and freezing unit.

[0013] In some embodiments, the speed of the defrosting fan is controlled in multiple different stages, including a heating stage and a cooling stage, according to the change in the evaporator temperature. This further includes: switching to the cooling stage after the evaporator temperature reaches the maximum defrosting temperature; and controlling the speed of the defrosting fan to decrease during the cooling stage. The speed of the defrosting fan begins to decrease from the speed at the end of the second heating stage, and the speed gradually decreases in units of a third speed value, where the third speed value is the speed reduction of the defrosting fan for each unit temperature decrease in the evaporator temperature, and the third speed value is greater than the first speed value.

[0014] The above technical solution has the following advantages or beneficial effects: During the process of evaporator temperature reduction, the speed of defrosting fan decreases, ensuring that the hot air generated by evaporator defrosting cannot enter the storage compartment. At the same time, excessively high defrosting fan speed wastes energy and causes excessive power consumption of refrigeration and freezing equipment.

[0015] In some embodiments, the defrosting control method further includes: when the evaporator temperature reaches a second temperature threshold, controlling the defrosting heating element to stop heating and controlling the defrosting fan to continue operating, wherein the second temperature threshold is less than the maximum defrost temperature.

[0016] The above technical solution has the following advantages or beneficial effects: when the evaporator temperature reaches the second temperature threshold, the defrosting heating element for defrosting the evaporator is controlled to stop heating. At this time, the evaporator temperature is still high, and the defrosting fan continues to operate to prevent the hot air generated during evaporator defrosting from entering the storage room.

[0017] In some embodiments, the defrosting control method further includes: obtaining the cumulative time for the defrosting fan to continue operating from the moment the defrosting heating element stops heating; and controlling the compressor to start and perform cooling operation when the cumulative time reaches a first time threshold.

[0018] The above technical solution has the following advantages or beneficial effects: after the defrosting heating element stops heating, when the defrosting fan runs for a cumulative time until the first time threshold is reached, the evaporator temperature has dropped significantly. At this time, the compressor can start cooling operation, allowing the low-temperature refrigerant to enter the evaporator and lower the evaporator temperature.

[0019] In some embodiments, the defrosting control method further includes: recording the time of the compressor's refrigeration operation; and when the time of the compressor's refrigeration operation reaches a second time threshold, controlling the defrosting fan to stop and controlling the refrigeration fan to start.

[0020] The above technical solution has the following advantages or beneficial effects: when the compressor's refrigeration operation time reaches the second time threshold, the evaporator can already carry out refrigeration work, the refrigeration fan starts, and cold air enters the storage compartment. At this time, the refrigeration and freezing unit is working normally, and the defrosting fan stops.

[0021] In some embodiments, the defrosting fan start-up temperature threshold value satisfies: (-15℃) - T℃≤T 启 ≤ (-15℃) + T℃, T 启 The defrosting fan start-up temperature threshold is... T is the fluctuation tolerance limit; and / or, the second temperature threshold is lower than the conventional defrost exit temperature of the refrigeration and freezing device, the conventional defrost exit temperature being the defrost exit temperature set in the conventional defrost program of the refrigeration and freezing device, the conventional defrost program including: entering the defrost mode, controlling the defrost heating element to start to heat the evaporator, and when the temperature of the evaporator surface rises to the defrost exit temperature, turning off the defrost heating element and exiting the defrost mode.

[0022] The above technical solution has the following advantages or beneficial effects: the defrost fan start-up temperature threshold can be set by preset fluctuation range limit value, and the start-up temperature threshold can be set according to different situations of different refrigeration and freezing devices. Since the unused hot air is applied to the evaporator by the defrost fan, the defrosting efficiency of the evaporator is high, and the defrosting exit temperature is lower than the conventional defrosting exit temperature of the refrigeration and freezing device.

[0023] This invention provides a refrigeration and freezing device, comprising: a front cover plate of an air duct, a rear cover plate of an air duct, and an inner liner of the refrigeration and freezing device. The front cover plate and the rear cover plate of the air duct form an air duct, and the rear cover plate of the air duct and the inner liner of the refrigeration and freezing device form an evaporator compartment. The rear cover plate of the air duct has an air inlet. A refrigeration circuit includes a compressor, an evaporator, a throttling device, and a condenser, wherein the evaporator is located in the evaporator compartment. A refrigeration fan is located in the air duct and disposed at the air inlet, and is used to generate a cooling fan in refrigeration mode. The device rotates in two directions to transfer the cooling capacity of the evaporator to the storage compartment through the air inlet and the air duct; a defrost fan is located in the evaporator compartment and is positioned at the air inlet; a temperature sensor is used to detect the evaporator temperature; a defrost heating element is located inside the evaporator compartment; and a controller is connected to the temperature sensor, the defrost heating element, the compressor, the cooling fan, and the defrost fan, and is used to execute the defrost control method described in the above embodiments in defrost mode.

[0024] According to the refrigeration and freezing apparatus of the present invention, the evaporator temperature is acquired in real time during the defrosting process. When the evaporator temperature reaches the defrosting fan start-up temperature threshold, the defrosting fan is started to rotate in a first rotation direction. The change in evaporator temperature is divided into multiple stages, and the speed of the defrosting fan is controlled according to different stages, thereby preventing hot air from the evaporator compartment from entering the air duct, inhibiting the entry of defrosting hot air into the storage compartment, reducing the temperature rise in the storage compartment caused by defrosting, and at the same time, the unused hot air is applied to the evaporator by the defrosting fan, thereby improving the defrosting efficiency of the evaporator.

[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0027] Figure 1 This is a schematic diagram of the structure of a refrigeration and freezing apparatus according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of a refrigeration and freezing apparatus according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of a defrosting fan structure according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of a duct assembly according to an embodiment of the present invention;

[0031] Figure 5 This is a flowchart of a defrosting control method according to an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the evaporator temperature, defrost fan inlet temperature, and power according to an embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of the gas volume corresponding to different temperatures and pressures in the evaporator chamber according to an embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the pressure-flow rate (PQ) curves of a defrosting fan at different speeds according to an embodiment of the present invention;

[0035] Figure 9 This is a schematic diagram of the hot air flow direction during the defrosting process of an evaporator without a defrosting fan, according to an embodiment of the present invention.

[0036] Figure 10 This is a schematic diagram of the hot air flow direction during the defrosting process of an evaporator according to an embodiment of the present invention;

[0037] Figure 11 This is a schematic diagram showing the arrangement of points at different locations on the same freezing tray according to an embodiment of the present invention;

[0038] Figure 12 This is a schematic diagram of the temperature curves of the freezer tray, the defrost fan inlet, and the evaporator according to an embodiment of the present invention.

[0039] Figure 13 This is a flowchart of a defrosting control process according to an embodiment of the present invention;

[0040] Figure 14 This is a schematic diagram of a refrigeration and freezing apparatus according to an embodiment of the present invention;

[0041] Figure 15 This is a structural block diagram of a refrigeration and freezing apparatus according to an embodiment of the present invention;

[0042] Figure 16 This is a schematic diagram of a refrigeration and freezing apparatus according to an embodiment of the present invention.

[0043] Figure label:

[0044] Refrigeration and freezing unit 100;

[0045] 10. Front cover plate of air duct; 11. Rear cover plate of air duct; 12. Inner liner of refrigeration and freezing unit; 1. Refrigeration fan; 2. Defrosting fan; 13. Air duct; 14. Evaporator compartment; 15. Air duct foam; 16. Air inlet; 110. Cabinet; 111. Compartment; 3. Condenser; 5. Liquid receiver; 6. Throttling device; 7. Gas-liquid separator; 8. Evaporator; 9. Compressor; 120. Temperature sensor; 130. Controller; 140. Defrosting heating element; 17. Water tray; 18. Tray; 19. First tray detection point; 20. Second tray detection point; 21. Defrosting fan blades; 22. Defrosting fan bracket. Detailed Implementation

[0046] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0047] Refrigeration and freezing units are common household appliances. They consist of a cabinet that defines the storage space and multiple doors located at the opening of the cabinet. The cabinet is the main body of the overall structure and is usually made of insulation material to maintain the low temperature environment inside. Refrigeration and freezing units are typically equipped with a refrigerator compartment, a freezer compartment, and doors. The doors are equipped with sealing strips to ensure that cold air does not leak out. The interior of the refrigerator compartment may have shelves, drawers, and storage racks for categorizing and storing food.

[0048] After prolonged use, frost forms on the evaporator surface of existing refrigeration and freezing units, leading to decreased cooling performance. At this point, the unit stops cooling and activates the defrosting heater to heat the evaporator for defrosting. During defrosting, the evaporator compartment temperature rises, and the hot gas from the evaporator compartment flows into the storage compartments through the air ducts, causing the temperature in each compartment to rise. This temperature increase in the freezer compartment leads to thawing, affecting the shelf life of food. Thawed food then refreezes during refrigeration; this cyclical "thawing + freezing" results in poor food preservation, causing food to stick together. Furthermore, temperature fluctuations increase refrigeration energy consumption.

[0049] Currently, defrosting control methods for refrigeration and freezing units improve the defrosting temperature rise problem through the following aspects: 1. Uniform defrosting, which controls the defrosting process by heating the evaporator through membrane heating or heating wire; 2. Low-temperature defrosting, which controls the defrosting temperature inside the evaporator compartment; 3. Using a motor-driven shielding mechanism to shield the fan. The shielding mechanism is located at the fan outlet to prevent hot air from flowing into the storage compartment. However, current methods cannot prevent the temperature in the storage compartment from rising during the defrosting process, resulting in poor preservation effect of the refrigeration and freezing unit and low defrosting efficiency of the evaporator.

[0050] To address the aforementioned problems, a first aspect of this invention proposes a defrosting control method for a refrigeration and freezing device, which may include, but is not limited to, refrigerators and freezers. This method involves activating a defrosting fan during the defrosting process, rotating it in a first direction opposite to the rotation direction of the refrigeration fan in cooling mode. The defrosting fan speed is controlled based on changes in evaporator temperature to suppress the entry of hot air from the evaporator compartment into the air duct, thereby reducing the temperature rise in the storage compartment caused by defrosting.

[0051] Figure 1 This is a schematic diagram of the structure of a refrigeration and freezing device according to an embodiment of the present invention, as shown below. Figure 1 As shown, the refrigeration and freezing unit 100 includes: a front cover plate 10 for the air duct, a rear cover plate 11 for the air duct, and air duct foam 15. For example... Figure 2 As shown, the refrigeration and freezing device 100 also includes a refrigeration and freezing device inner liner 12.

[0052] Among them, such as Figure 2 As shown, the front cover plate 10 and the rear cover plate 11 of the air duct form the air duct 13, and the rear cover plate 11 and the inner liner 12 of the refrigeration and freezing unit form an evaporator compartment 14; as Figure 1 As shown, the rear cover plate 11 of the air duct has an air inlet 16.

[0053] like Figure 2 The air duct 13 shown includes a space constructed by a front cover plate 10 and a rear cover plate 11, such as Figure 1 As shown, a cooling fan 1 is installed in the air duct, and the rear cover plate 11 of the air duct has an air inlet 16. A defrosting fan 2 is installed at the air inlet of the rear cover plate 11. The defrosting fan 2 is mounted on the rear cover plate 11 of the air duct, with the center of the defrosting fan 2 directly facing the center of the air guide ring at the air inlet of the air duct, and the gap between the lowest point of the defrosting fan 2 blades and the air guide ring is 5mm. Figure 3 The diagram shows the structure of defrosting fan 2. The defrosting fan blades 21 are fixed to the defrosting fan bracket 22, which has screw fixing structures on both sides. The final assembly drawing of the air duct is shown below. Figure 4 As shown.

[0054] In some embodiments, such as Figure 5 The defrosting control method shown includes steps S1-S3.

[0055] Step S1: Obtain the evaporator temperature.

[0056] Specifically, after prolonged use, frost will form on the surface of the evaporator of a refrigeration and freezing unit, resulting in poor cooling performance. To prevent frost on the evaporator surface from affecting the cooling performance of the refrigeration and freezing unit, it is necessary to defrost the evaporator by heating. In defrost mode, the defrost heating element is activated to remove the frost layer on the evaporator surface.

[0057] During defrosting heating, the evaporator temperature rises, and high-temperature gas flows into the storage room through the air duct, causing the storage room temperature to rise. In this invention, a defrosting fan is installed at the air inlet of the air duct rear cover. In defrosting mode, when defrosting the evaporator, the evaporator temperature is obtained in real time through a temperature sensor. If the evaporator temperature is too high, the defrosting fan is activated to prevent high-temperature gas from entering the storage room through the air duct.

[0058] Step S2: When the evaporator temperature reaches the defrost fan start-up temperature threshold, control the defrost fan to rotate in the first rotation direction. The first rotation direction is opposite to the second rotation direction, which is the rotation direction of the refrigeration fan in the cooling mode.

[0059] Specifically, after prolonged use, frost forms on the evaporator surface of the refrigeration and freezing unit. The evaporator is then heated to defrost. During defrosting, a temperature sensor continuously monitors the evaporator temperature. When the evaporator temperature reaches the defrost fan activation temperature threshold, the defrost fan is activated and controlled to rotate in a first direction. The second direction of rotation is the direction of rotation in the refrigeration mode of the cooling fan. Since the first and second rotation directions are opposite, hot air from the evaporator compartment is prevented from entering the storage compartment through the air duct. The defrost fan activation temperature threshold can be understood as a value set to determine whether the defrost fan should be activated during evaporator defrosting. The defrost fan activation temperature threshold varies depending on the type of refrigeration and freezing unit; for example, it can be -16.5℃, -15℃, or -13.5℃.

[0060] The defrosting fan is set to rotate in the first direction to prevent air from the evaporator space from entering the storage compartment of the refrigeration unit through the air inlet of the cover plate. When the refrigeration unit is working normally, the refrigeration fan in the air duct blows cold air into the storage compartment. When the evaporator is heating up to defrost, the refrigeration fan stops working, but high-temperature gas will still enter the storage compartment through the air duct. At this time, the defrosting fan rotates in the opposite direction to the refrigeration fan to blow the high-temperature gas generated by the evaporator heating and defrosting back to the evaporator, thus preventing high-temperature gas from entering the storage compartment.

[0061] Step S3: Control the speed of the defrosting fan according to the changes in evaporator temperature in multiple different stages of heating and cooling.

[0062] Specifically, the temperature change of the evaporator is divided into several stages, including a heating stage and a cooling stage. The heating stage involves heating the evaporator to defrost it; the cooling stage occurs after defrosting is complete and heating stops, allowing the evaporator to cool down. To prevent high-temperature gas from entering the storage compartment through the air duct and to reduce the power consumption of the defrosting fan, the fan speed needs to be controlled according to different stages. If the defrosting fan speed remains constant, a setting that is too low will not prevent high-temperature gas from entering the storage compartment, while a setting that is too high will result in excessive power consumption. Therefore, the defrosting fan speed is adjusted in real time according to different stages to prevent high-temperature gas from entering the storage compartment and reduce the defrosting fan's power consumption. Since the evaporator is no longer heated during the cooling stage, its temperature gradually decreases to room temperature. At this time, the temperature of the gas passing through the air duct also decreases significantly. Therefore, the change in defrosting fan speed during the cooling stage is greater than that during the heating stage.

[0063] For example, in existing refrigeration and freezing systems, defrosting heat enters the freezer compartment during the defrosting process, causing the freezer compartment temperature to rise and resulting in the thawing of food. This invention installs a defrosting fan on the rear cover of the air duct. During the defrosting process, the defrosting fan starts and rotates in reverse, blowing the defrosting heat towards the evaporator side, inhibiting the defrosting heat from entering the freezer compartment, preventing the freezer compartment temperature from rising, and improving the preservation performance. At the same time, the unused heat is applied to the evaporator by the defrosting fan, which can improve the defrosting efficiency of the evaporator.

[0064] During normal defrosting, after the refrigeration / freezing unit has been running normally for N hours, a layer of frost will form on the evaporator surface, initiating the defrosting program. The program controls the heating element to start heating, and the evaporator begins defrosting. Due to differences in model and evaporator size, the defrosting cycle varies, typically between 30 and 50 minutes. The defrosting cycle ends when the temperature sensor detects that the evaporator temperature is T. 退 Time (generally T) 退 (At 4℃~10℃), once the frost layer around the evaporator has completely melted, the program-controlled heating wire stops heating, and the defrosting process ends.

[0065] This invention assembles a defrosting fan on the rear cover plate of the air duct, and proposes a defrosting control method for refrigeration and freezing devices. 启 The defrosting fan is set to start at a specific temperature. When the temperature sensor detects that the evaporator temperature reaches T... 启 That is, when the defrosting fan starts at the temperature threshold, the defrosting fan starts. 启 <0℃, the defrosting fan start-up temperature threshold can be -16.5℃, -15℃, or -13.5℃. T 退 The defrost exit temperature is set when the temperature sensor detects that the evaporator temperature has reached T. 退 At that time, the heating wire stops working, T 退The temperature is lower than the defrost exit temperature of existing refrigeration and freezing units because the unused heat is applied to the evaporator by the defrost fan, which can improve the defrost efficiency of the evaporator, so defrosting can be completed at a lower temperature.

[0066] According to the defrosting control method of the present invention, the evaporator temperature is acquired in real time during the defrosting process. When the evaporator temperature reaches the defrosting fan start-up temperature threshold, the defrosting fan is started to rotate in a first rotation direction. The change in evaporator temperature is divided into multiple stages, and the speed of the defrosting fan is controlled according to different stages, thereby preventing hot air from entering the air duct of the evaporator compartment, inhibiting the entry of defrosting hot air into the storage compartment, reducing the temperature rise in the storage compartment caused by defrosting, and at the same time, the unused hot air is applied to the evaporator by the defrosting fan, thereby improving the defrosting efficiency of the evaporator.

[0067] In some embodiments, the speed of the defrosting fan is controlled in multiple different stages, including a heating stage and a cooling stage, based on the change in evaporator temperature. This includes: when the evaporator temperature is in the first heating stage, which is the stage from the defrosting fan start-up temperature threshold to the first temperature threshold, the speed of the defrosting fan is controlled to increase from the minimum allowable speed until the evaporator temperature reaches the first temperature threshold; wherein, the speed of the defrosting fan is gradually increased in units of a first speed value, where the first speed value is the speed increase of the defrosting fan for each unit increase in evaporator temperature.

[0068] Specifically, the change in evaporator temperature includes multiple stages, which are divided into heating and cooling stages. The heating stage includes a first heating stage, which is the stage from the defrost fan start-up temperature threshold to the first temperature threshold. In other words, the temperature sensor monitors the evaporator temperature in real time. If the evaporator temperature is greater than the defrost fan start-up temperature threshold, the first heating stage begins. The first heating stage ends when the temperature sensor detects that the evaporator temperature is at the first temperature threshold. The first temperature threshold can be understood as a value set to distinguish between the first heating stage and the maintenance stage. For example, the first temperature threshold can be 0°C. The first heating stage is the stage from the start of defrosting to the evaporator temperature reaching 0°C.

[0069] During the first heating stage, the temperature sensor monitors the evaporator temperature in real time. If the evaporator temperature is higher than the defrost fan start-up temperature threshold, the defrost fan starts. At this time, the defrost fan operates at the set minimum allowable speed. Since the evaporator is heated during the first heating stage, the evaporator temperature will continue to rise. Therefore, the defrost fan speed is increased according to the rising temperature and the first speed value.

[0070] For example, such as Figure 6 The diagram shows the evaporator temperature, defrost fan inlet temperature, and power. The power refers to the total power of the unit, which may include, for example, the compressor power and the defrost fan power. Figure 6 As can be seen, the evaporator temperature changes unevenly throughout the defrosting process. At the start of defrosting, a small amount of hot air passes through the air inlet, at which point the defrosting fan operates at its lowest speed of 200 r / min. As defrosting continues, the temperature gradually rises, and the fan speed increases accordingly. The defrosting fan speed is adjusted based on the temperature change value ΔT from the temperature sensor. The study is divided into four stages. Point C (-15℃) is the evaporator defrosting start point. Stage CD is the first heating stage, where the temperature sensor temperature rises from -15℃ to 0℃. For every 1℃ increase, the fan speed is increased by the first change, i.e., by 15 r / min. The fan speed ω... CD =200+15ΔT, where 200 is the minimum allowable speed of the defrosting fan, ΔT is the temperature change value of the temperature sensor, and the maximum speed ω is when the temperature sensor reaches the first temperature threshold of 0℃ in segment CD. CD The speed is 425 r / min.

[0071] In some embodiments, the speed of the defrosting fan is controlled in multiple different stages, including a heating phase and a cooling phase, according to the change in evaporator temperature. The control further includes: when the evaporator temperature is in the second heating phase, controlling the speed of the defrosting fan to continue increasing until the evaporator temperature reaches the maximum defrost temperature, which is greater than a first temperature threshold. The speed of the defrosting fan is gradually increased in units of a second speed value, where the second speed value is the speed increase of the defrosting fan per unit increase in evaporator temperature, and the second speed value is less than the first speed value.

[0072] Specifically, the heating stage also includes a second heating stage. A temperature sensor monitors the evaporator temperature in real time, and the second heating stage begins when the evaporator temperature reaches the first temperature threshold and then the maximum defrost temperature. The maximum defrost temperature is the temperature at which the evaporator stops heating. To ensure complete defrosting of the evaporator, heating continues even after the evaporator temperature reaches the first temperature threshold. Therefore, the maximum defrost temperature is greater than the first temperature threshold; for example, the maximum defrost temperature can be 8℃, 9℃, or 10℃.

[0073] During the second heating stage, the temperature sensor monitors the evaporator temperature in real time. If the evaporator temperature is greater than the first temperature threshold, the speed of the defrosting fan increases from the speed during the maintenance stage until the evaporator temperature reaches the maximum defrost temperature. Since the evaporator heats up more slowly during the second heating stage, the second speed value is less than the first speed value.

[0074] For example, such as Figure 6 As shown, segment EF represents the second heating stage, and the defrosting fan speed increases accordingly. If the maximum defrosting temperature is 20℃, the evaporator temperature increases from 0℃ to 20℃ from the first temperature threshold. For every 1℃ increase, the speed is increased by the second variable, which is equivalent to increasing the fan speed by 4 r / min. EF =ωCD +4ΔT, when the temperature sensor reaches its maximum value, the defrosting fan speed is 505 r / min.

[0075] In some embodiments, the change in evaporator temperature further includes a maintenance phase, which is located between the first heating phase and the second heating phase in time; during the second heating phase, the speed of the defrosting fan is increased from the speed of the defrosting fan at the end of the maintenance phase; the defrosting control method further includes: entering the maintenance phase when the evaporator temperature reaches a first temperature threshold; and controlling the defrosting fan to maintain a constant speed when the evaporator temperature is in the maintenance phase.

[0076] Specifically, the evaporator temperature change also includes a maintenance phase. The first heating phase is the period from the defrost fan start-up temperature threshold to the first temperature threshold. After the first heating phase, a maintenance phase begins. The temperature sensor monitors the evaporator temperature in real time. When the evaporator temperature reaches the first temperature threshold, the maintenance phase begins. During the maintenance phase, the temperature sensor continuously monitors the evaporator temperature at 0°C. Since the frost layer absorbs heat during defrosting, the evaporator temperature remains constant during the maintenance phase. Because the evaporator temperature remains constant during the maintenance phase, the temperature of the high-temperature gas entering the storage compartment through the air duct remains constant, so the defrost fan maintains a constant speed.

[0077] For example, such as Figure 6 As shown, segment DE is the maintenance phase, where the temperature sensor temperature remains at 0℃, so the defrosting fan speed remains constant. ω DE =ω CD =200+15ΔT, defrosting fan speed is maintained at 425r / min.

[0078] In some embodiments, the defrosting control method further includes: controlling the defrosting heating element to stop heating and controlling the defrosting fan to continue operating when the evaporator temperature reaches a second temperature threshold, wherein the second temperature threshold is less than the maximum defrost temperature.

[0079] Specifically, during the evaporator defrosting process, a temperature sensor monitors the evaporator temperature in real time. When the evaporator temperature reaches the defrost exit temperature, the frost layer on the evaporator surface melts completely. At this point, the defrost heating element, which controls the defrosting heating of the evaporator, stops heating. The defrost exit temperature is lower than the maximum defrost temperature because the remaining heat will still cause the evaporator temperature to rise after the defrost heating element stops heating. Even after the defrost heating element stops heating, the high temperature generated by the evaporator will still enter the storage compartment through the air duct. Therefore, after the defrost heating element stops heating, the defrost fan continues to run.

[0080] In some embodiments, the defrosting fan speed is controlled in multiple different stages, including a heating phase and a cooling phase, according to the change in evaporator temperature. This further includes: switching to the cooling phase after the evaporator temperature reaches the maximum defrost temperature; during the cooling phase, controlling the defrosting fan speed to decrease; wherein the defrosting fan speed begins to decrease from the end of the second heating phase, and the defrosting fan speed gradually decreases in units of a third speed value, where the third speed value is the speed decrease of the defrosting fan for each unit temperature decrease in the evaporator temperature, and the third speed value is greater than the first speed value.

[0081] Specifically, after the heating phase ends, the cooling phase begins. The defrosting heating element stops heating the evaporator, and the evaporator temperature continues to decrease. During the cooling phase, the speed of the defrosting fan decreases from the speed at the end of the second heating phase to a third speed value that varies with temperature. The temperature sensor monitors the evaporator temperature in real time. For every degree the evaporator temperature decreases, the defrosting fan speed decreases by the third speed value. Because the evaporator cools down relatively quickly during the cooling phase, the third speed value is greater than the first speed value.

[0082] For example, such as Figure 6 As shown, stage FG is the cooling stage, where the heating wire stops heating, the temperature sensor temperature decreases, and consequently, the defrosting fan speed decreases; ω FG =ω EF -25ΔT, when the refrigeration fan starts, the defrosting fan stops working.

[0083] Depend on Figure 6 As can be seen, the temperature collected by the temperature sensor first rises and then falls during the entire defrosting process of the evaporator. The temperature change trend of the defrosting fan inlet is similar to that of the evaporator. Therefore, the temperature change of the evaporator is taken as the driving basis for the speed of the defrosting fan.

[0084] Defrosting begins when the heating element heats the evaporator, raising its temperature. When the evaporator temperature reaches point C, the pressure generated by the hot steam at the defrosting fan inlet is approximately P. C The defrosting fan starts at a speed ω = N + K1ΔT (where N is the minimum speed of the defrosting fan, a constant, and K1 is a coefficient). The pressure caused by the defrosting fan is P. 风机 At this time, P C =P 风机 This ensures pressure balance on both sides of the defrost blower inlet. As heating continues, the temperature rises, and according to the gas law and theoretical derivation, the pressure at the defrost blower inlet continuously increases. The defrost blower speed is adjusted by the temperature change ΔT from the temperature sensor to maintain pressure balance on both sides of the defrost blower inlet.

[0085] In the CDEF stage, the evaporator temperature rises, and the defrost fan speed needs to continuously increase to balance the pressure caused by the temperature rise. In the FG stage, the temperature drops, the heating element stops heating, and the evaporator temperature drops. Due to the temperature drop, the pressure at the defrost fan inlet decreases, causing the speed ω to decrease. When the refrigeration fan starts, the defrost fan stops, and a new refrigeration cycle begins.

[0086] Furthermore, such as Figure 7 As shown, during the defrosting process of a refrigeration and freezing unit, the heating wire heats the air temperature in the evaporator compartment; as the heating wire heats, the air temperature T in the evaporator compartment continuously rises, and the gas volume expands. The ideal gas law is: PV=nRT.

[0087] Where P is the gas pressure (unit: Pa); V is the gas volume (unit: m³); n is the amount of substance of the gas, a constant (unit: mol); T is the thermodynamic temperature (unit: K); and R is the universal gas constant, with a value of 8.314 J / (mol·K).

[0088] As the air volume inside the evaporator chamber increases, if left unobstructed, this continued expansion will create convection at the defrost fan inlet, allowing hot air to enter the compartment. Before heating, the gas satisfies P1V1=nRT1. After heating, to prevent hot air from entering the compartment through convection, the volume after heating is V2=V1, the volume before heating is V1, the temperature before heating is T1, the pressure before heating is P1, the volume after heating is V2, the temperature after heating is T2, and the pressure after heating is P2, which satisfies the formula P1V1 / T1=P2V2 / T2. The temperature after heating, T2, is greater than the temperature before heating, T1, so P2>P1. The defrost fan inlet area is S. From the basic pressure formula, F2=P2×S, where F2 is the pressure at the defrost fan inlet after heating. During the heating process, the pressure at the air inlet of the defrosting fan continuously rises. There should be a reverse pressure, -F2, acting on the heating gas to maintain pressure balance between the storage room and the evaporator chamber. This pressure is provided by the defrosting fan.

[0089] According to Charles's Law, for a given mass of a gas with constant volume, the pressure P is directly proportional to the thermodynamic temperature T, expressed by the formula: P = CT; where C is a constant.

[0090] Pressure-flow (PQ) curves of defrosting blowers at different speeds are shown below. Figure 8 As shown in the figure, the rotational speeds ω1 < ω2 < ω3. At a certain moment during heating, the pressure value rises to P due to the electric heating at the air guide ring position. A The defrosting fan starts running at a speed of ω1 and an air volume of Q. AAt this point, the pressure provided by the defrosting fan and the pressure caused by the electric heating remain equal at the defrosting fan inlet. As heating continues, the temperature at the defrosting fan inlet continues to increase, and the pressure at the defrosting fan inlet increases to P. B By maintaining Q A Without changing the speed, increase the fan speed ω2 to overcome the pressure generated by the electric heating at the defrosting fan inlet and maintain the pressure balance on both sides.

[0091] In some embodiments, the defrosting control method further includes: obtaining the cumulative time for the defrosting fan to continue operating from the moment the defrosting heating element stops heating; and controlling the compressor to start and perform cooling operation when the cumulative time reaches a first time threshold.

[0092] Specifically, after the defrosting heating element stops heating, the evaporator temperature begins to decrease, gradually dropping to room temperature. During the evaporator cooling process, high-temperature gas is still generated, so the defrosting fan continues to run to prevent high-temperature gas from entering the storage compartment. After the defrosting heating element stops heating, the cumulative time the defrosting fan continues to run is recorded. When the cumulative time the defrosting fan continues to run reaches the first time threshold, the compressor is controlled to run in cooling mode. The first time threshold can be understood as the time set to determine the compressor to start running after the defrosting heating element stops heating. When the cumulative time the defrosting fan continues to run reaches the first time threshold, the evaporator has dropped to room temperature. At this time, the compressor runs in cooling mode to continue cooling the evaporator.

[0093] In some embodiments, the defrosting control method further includes: recording the time of compressor refrigeration operation; and when the time of compressor refrigeration operation reaches a second time threshold, controlling the defrosting fan to stop and controlling the refrigeration fan to start.

[0094] Specifically, after the defrosting heating element stops heating, when the cumulative time of the defrosting fan continues to run reaches the first time threshold, the compressor is controlled to run in a cooling mode. When the time of the compressor running in a cooling mode reaches the second time threshold, the evaporator can cool the storage compartment of the refrigeration and freezing unit. At this time, the refrigeration fan starts and blows the cold air generated by the evaporator into the storage compartment. At this time, the defrosting fan stops and the defrosting of the evaporator ends.

[0095] For example, such as Figure 9 The diagram shows the hot air flow direction during the evaporator defrosting process. During defrosting, the defrosting heating element 140 heats the evaporator surface, melting the frost layer and allowing it to flow into the drip tray 17. The total defrosting hot air is V, and the hot air entering the compartment is V1. If no defrosting fan is installed, the total defrosting heat rises with the hot air, and some of this heat enters the air duct from the air inlet and then reaches the freezer compartment, causing the freezer temperature to rise. This is a schematic diagram of the hot air flow direction during the evaporator defrosting process of the present invention. Figure 10As shown, after the defrosting fan is installed, the defrosting fan rotates and blows the hot air V1 that originally entered the compartment into the evaporator compartment, which suppresses the temperature rise of the compartment during the defrosting process and at the same time increases the temperature inside the evaporator compartment, thus accelerating the defrosting efficiency. Therefore, the heating time of this solution is shortened, so the defrosting exit temperature of this invention is lower than the defrosting exit temperature of existing refrigeration and freezing devices.

[0096] After the heating element stops working, the temperature inside the evaporator compartment remains high. The defrosting fan continues to operate, preventing defrosting heat from entering the compartment while simultaneously circulating it within the evaporator compartment. After an interval of h1 (the first time threshold), once the water dripping from the evaporator surface has stopped, the compressor begins cooling operation. At this time, the remaining heat in the evaporator compartment interacts with the cold air until the residual defrosting heat is consumed. After the compressor has been running for h2 (the second time threshold), the cooling fan starts, while the defrosting fan stops. By this time, the defrosting heat has been completely consumed, and the evaporator's cooling capacity is directly carried into the compartment by the cooling fan, achieving rapid cooling of the freezer compartment.

[0097] In existing solutions, unused defrosting heat can enter the freezer compartment during the heating wire's operation. Even after defrosting, residual defrosting heat still enters the freezer compartment. When the refrigeration fan starts, the residual heat in the evaporator compartment is quickly carried into the freezer compartment by the fan. Throughout the defrosting process until the refrigeration fan starts, heat enters the freezer compartment, causing the freezer temperature to rise. Alternatively, existing inventions use a defrosting duct, where the refrigeration fan reverses direction to redirect defrosting heat back into the evaporator compartment. However, this method suffers from significant heat loss due to the duct's passage through the evaporator compartment, resulting in low heat utilization. Furthermore, it doesn't account for defrosting heat entering the storage compartment, making it impossible to prevent this. This invention utilizes the reverse rotation of the defrosting fan to effectively suppress defrosting heat entering the freezer compartment. Simultaneously, it directs unused defrosting heat towards the evaporator compartment, preventing circulation to other compartments. This improves evaporator defrosting efficiency, shortens defrosting time, enhances the preservation performance of the refrigeration and freezing system, and reduces energy consumption.

[0098] Furthermore, temperature data were collected at different locations on the freezing trays within the freezing compartment of the refrigeration and freezing unit, such as... Figure 11As shown, a first tray detection point 19 and a second tray detection point 20 are set on the same tray 18 in the freezer compartment. The first tray detection point 19 and the second tray detection point 20 are located on both sides of the same tray 18 to accurately collect the temperature of the tray 18. The tray 18 is set at the same position in the freezer compartment of both the present invention's refrigeration and freezing device and existing refrigeration and freezing devices, and the first tray detection point 19 and the second tray detection point 20 are fixedly set at positions within the tray 18. At the end of defrosting, the temperature rise of the freezer compartment of both the present invention's refrigeration and freezing device and existing refrigeration and freezing devices is obtained by collecting the temperatures of the first tray detection point 19 and the second tray detection point 20. The temperature data collected at different positions on the tray 18 in the freezer compartment are shown in Table 1 below:

[0099] Table 1 Temperature Acquisition Data Table

[0100]

[0101] Experimental data shows that in existing refrigeration and freezing devices, the temperature rise at the first tray detection point is 4.1℃, and the temperature rise at the second tray detection point is 5.4℃. In contrast, the refrigeration and freezing device of this invention shows a temperature rise of 2.9℃ at the first tray detection point and 4.3℃ at the second tray detection point. The average temperature rise is 1.15℃ lower than the prototype, demonstrating the effectiveness of this invention in reducing the defrosting temperature rise in the freezer compartment. Because this invention's refrigeration and freezing device can control the defrosting fan speed at different stages, it directs the defrosting heat towards the evaporator side, inhibiting the entry of defrosting heat into the storage compartment and reducing the temperature rise in the storage compartment due to defrosting. Simultaneously, the unused heat is applied to the evaporator by the defrosting fan, improving the evaporator's defrosting efficiency. Therefore, this invention's refrigeration and freezing device can complete defrosting faster and prevent defrosting heat from entering the storage compartment.

[0102] In some embodiments, the defrosting fan start-up temperature threshold value satisfies: (-15℃) - T℃≤T 启 ≤ (-15℃) + T℃, T 启 The starting temperature threshold for the defrosting fan. T is the fluctuation tolerance limit; and / or, the second temperature threshold is lower than the conventional defrost exit temperature of the refrigeration and freezing unit. The conventional defrost exit temperature is the defrost exit temperature set in the conventional defrost program of the refrigeration and freezing unit. The conventional defrost program includes: entering the defrost mode, controlling the defrost heating element to start to heat the evaporator, and when the temperature of the evaporator surface rises to the defrost exit temperature, turning off the defrost heating element and exiting the defrost mode.

[0103] Specifically, depending on the type of refrigeration and freezing unit, the defrost fan start-up temperature threshold is set differently. When the evaporator is heated for defrosting, after the defrost heating element, such as the heating wire, has been working for a period of time, the defrost fan starts when the temperature sensor detects that the evaporator temperature has reached the defrost fan start-up temperature threshold, thus preventing defrost heat from entering the freezer compartment. Due to the action of the defrost fan, unused heat is blown towards the evaporator compartment, making full use of the generated defrost heat, improving defrost efficiency, and shortening defrost time. Therefore, the defrost exit temperature is lower than the conventional defrost exit temperature of refrigeration and freezing units.

[0104] For example, such as Figure 12 The diagram shows the temperature curves of the freezer tray, defrost fan inlet, and evaporator. When the defrost program starts, the defrost heating element, such as the heating wire, begins to work, and the temperatures of the temperature sensor and defrost fan inlet rise. At point A, the temperatures of the defrost fan inlet and the freezer tray are equal. At this point, the temperature sensor temperature at point B (-16.5℃) is the lowest value of the defrost fan's starting temperature. This is because at this node, the hot air inside the evaporator compartment, which is hotter than the air in the freezer compartment, is about to enter the freezer compartment, potentially causing the freezer compartment temperature to rise. As heating continues, the temperatures of the temperature sensor and the defrost fan inlet continue to rise. When the defrost fan inlet temperature reaches point A1 (-15℃), the temperature sensor temperature at point B1 (-13.5℃) is the highest point of the temperature sensor's starting temperature. The defrosting temperature rise needs to be controlled within 3K. "K" (Kelvin) is a unit of temperature difference; 1K equals 1℃ of temperature change. Generally, the freezer compartment temperature is controlled below -18℃. A 3K temperature rise reaches -15℃. The temperature entering the freezer compartment should be controlled below -15℃. Therefore, B1 (-13.5℃) is the maximum value, meaning -16.5℃ ≤ T. 启 ≤-13.5℃.

[0105] This invention acquires the evaporator temperature in real time during the defrosting process. When the evaporator temperature reaches the defrosting fan start-up temperature threshold, the defrosting fan is started and rotated in a set direction. The change in evaporator temperature is divided into multiple stages, and the speed of the defrosting fan is controlled according to different stages. This blows the hot air generated during defrosting towards the evaporator side, inhibiting the hot air from entering the storage compartment and reducing the temperature rise in the storage compartment caused by defrosting. At the same time, the unused hot air is applied to the evaporator by the defrosting fan, improving the defrosting efficiency of the evaporator. As a result, the defrosting exit temperature of the refrigeration and freezing device of this invention is lower than the conventional defrosting exit temperature of refrigeration and freezing devices.

[0106] In some embodiments, the defrosting control process is described, and the specific steps are as follows: Figure 13 As shown.

[0107] Step S01: Defrosting begins.

[0108] Step S02: Defrosting heating element operates.

[0109] Step S03: Has the evaporator temperature reached the defrost exit temperature? If yes, proceed to step S04; otherwise, proceed to step S02.

[0110] Step S04: The defrosting heating element stops working.

[0111] Step S05: The compressor starts cooling.

[0112] Step S06: Start the refrigeration fan and control the defrosting fan to stop.

[0113] Specifically, in existing refrigeration and freezing units, when the evaporator is defrosting, the defrosting heating element, such as a heating wire, works to heat up and melt the frost on the evaporator. When the temperature sensor detects that the evaporator temperature has reached the defrosting exit temperature, the heating wire stops working. After a period of time, the compressor starts, and then the refrigeration fan starts, and one defrosting cycle ends.

[0114] The defrosting control process of this invention is as follows: When defrosting begins, the heating wire starts working, and the temperature inside the evaporator compartment rises. After the heating wire has been working for a period of time, the temperature sensor detects that the temperature has reached the first temperature threshold. The defrosting fan then starts rotating in reverse to suppress the entry of defrosting hot air into the compartment, while simultaneously directing the defrosting hot air towards the evaporator compartment to accelerate the melting of the frost layer on the evaporator surface. The defrosting heating wire starts first, followed by the defrosting fan, ensuring that the rising defrosting hot air melts the frost while excess hot air is reused, returning to the evaporator compartment to melt the frost layer on the evaporator surface, effectively improving defrosting efficiency. A variable frequency defrosting fan is used, controlling its speed in stages. A lower speed is used in the initial stage of defrosting to suppress a small amount of defrosting hot air; as the heating time lengthens and more defrosting hot air rises, a higher speed is used to achieve full coverage and downward pressure of the defrosting hot air. The use of a variable frequency defrosting fan can control the amount of cold air flowing out of the compartment, maintaining a stable temperature inside the freezer compartment.

[0115] A second aspect of the present invention provides a refrigeration and freezing device, which can be a refrigerator, freezer, etc. Figure 1 As shown, the refrigeration and freezing unit 100 includes: a front cover plate 10 for the air duct and a rear cover plate 11 for the air duct; as Figure 2 As shown, the refrigeration and freezing device 100 also includes a refrigeration and freezing device inner liner 12. The front cover plate 10 and the rear cover plate 11 of the air duct form an air duct 13, the rear cover plate 11 of the air duct and the inner liner 12 of the refrigeration and freezing device form an evaporator compartment 14, and the rear cover plate 11 of the air duct has an air inlet 16.

[0116] like Figure 14 As shown, the refrigeration circuit in the refrigeration and freezing unit 100 includes a condenser 3, a throttling device 6, an evaporator 8, and a compressor 9, wherein the evaporator 8 is located in the evaporator compartment.

[0117] The refrigeration process of the refrigeration unit 100 includes compression, condensation, throttling, and evaporation. The compression process is as follows: When the power cord of the refrigeration unit is plugged in and the thermostat contacts are closed, the compressor 9 starts working. Low-temperature, low-pressure refrigerant is drawn into the compressor 9 and compressed into high-temperature, high-pressure superheated gas in the compressor 9 cylinder before being discharged into the condenser 3. The condensation process is as follows: The high-temperature, high-pressure refrigerant gas dissipates heat through the condenser 3, and its temperature continuously decreases, gradually cooling into room-temperature, high-pressure saturated vapor, and further cooling into saturated liquid. The temperature at this point no longer decreases; this temperature is called the condensation temperature. The pressure of the refrigerant remains almost constant throughout the condensation process. The throttling process is as follows: After condensation, the saturated refrigerant liquid is filtered through the receiver 5 to remove moisture and impurities before flowing into the throttling device 6. Through this device, the pressure is reduced, and the refrigerant becomes room-temperature liquid. The refrigerant is a low-temperature, low-pressure wet vapor. The evaporation process is as follows: the low-temperature, low-pressure wet vapor begins to absorb heat and vaporize in the evaporator 8, which not only lowers the temperature of the evaporator 8 and its surroundings, but also turns the refrigerant into a low-temperature, low-pressure gas. The refrigerant coming out of the evaporator 8 passes through the gas-liquid separator 7 and returns to the compressor 9. The above process is repeated to transfer the heat inside the refrigeration and freezing unit to the air outside the unit, thus achieving the purpose of refrigeration. While achieving refrigeration, the refrigeration fan 1 forces airflow, evenly distributing the cold air generated by the evaporator 8 to all areas of the refrigeration and freezing unit, avoiding uneven temperature, accelerating the heat exchange process, reducing the running time of the compressor 9, reducing energy consumption, helping the condenser 3 and compressor 9 dissipate heat, and extending the equipment life.

[0118] The refrigeration and freezing unit 100 also includes a refrigeration fan 1 and a defrosting fan 2. The refrigeration fan 1 is located in the air duct and is set at the air inlet. It is used to rotate in a second rotation direction in the refrigeration mode to transfer the cold energy of the evaporator 8 to the storage compartment through the air inlet and the air duct. The defrosting fan 2 is located in the evaporator compartment and is set at the air inlet. The second rotation direction is the direction in which the refrigeration fan 1 rotates when it transfers the cold energy of the evaporator 8 to the storage compartment.

[0119] like Figure 15 As shown, the refrigeration and freezing device 100 can be a refrigerator, which includes a cabinet 110 and the cabinet 110 is configured to have at least one compartment 111.

[0120] The multiple compartments 111 can be divided into refrigerator and freezer compartments. The temperature of the refrigerator compartment is usually maintained between 0℃ and 10℃, and a uniform temperature distribution is achieved through corresponding evaporators and air circulation. The refrigerator compartment is suitable for storing frequently accessed items such as beverages and sauces, where temperature fluctuations are relatively large. The temperature of the freezer compartment is consistently maintained below -18℃. A corresponding evaporator is used to ensure a low-temperature environment. The freezer compartment can be equipped with pull-out drawers for easy access to bottom-layer foods. The freezer compartment also has tiered trays to prevent frozen foods from piling up and obstructing cold air circulation, and to prevent upper-layer foods from crushing lower layers during thawing.

[0121] like Figure 16 As shown, the refrigeration and freezing unit 100 can be a refrigerator, which includes a temperature sensor 120, a controller 130, and a defrosting heating element 140. The temperature sensor 120 is used to collect the temperature of the evaporator 8. The controller 130 is connected to the temperature sensor 120 and the defrosting heating element 140.

[0122] According to the refrigeration and freezing apparatus of the present invention, the evaporator temperature is acquired in real time during the defrosting process. When the evaporator temperature reaches the defrosting fan start-up temperature threshold, the defrosting fan is started to rotate in a first rotation direction. The change in evaporator temperature is divided into multiple stages, and the speed of the defrosting fan is controlled according to different stages, thereby preventing hot air from the evaporator compartment from entering the air duct, inhibiting the entry of defrosting hot air into the storage compartment, reducing the temperature rise in the storage compartment caused by defrosting, and at the same time, the unused hot air is applied to the evaporator by the defrosting fan, thereby improving the defrosting efficiency of the evaporator.

[0123] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0124] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A defrosting control method, characterized in that, Used in refrigeration and freezing equipment The refrigeration and freezing device includes an air duct consisting of a front cover plate and a rear cover plate, an inner liner of the refrigeration and freezing device, a compressor, an evaporator, a refrigeration fan, and a defrosting heating element. The rear cover plate and the inner liner of the refrigeration and freezing device form an evaporator compartment. The rear cover plate has an air inlet. The evaporator is located in the evaporator compartment. The refrigeration fan is located in the air duct and is positioned at the air inlet. The defrosting heating element is located inside the evaporator compartment. The refrigeration and freezing device also includes a defrosting fan, which is located in the evaporator compartment and is disposed at the air inlet; The defrosting control method includes: In defrost mode, the defrost heating element is controlled to start heating; Obtain the evaporator temperature; When the evaporator temperature reaches the defrost fan start-up temperature threshold, the defrost fan is controlled to rotate in a first rotation direction, which is opposite to the second rotation direction. The second rotation direction is the rotation direction of the refrigeration fan in the cooling mode. The speed of the defrosting fan is controlled according to the temperature change of the evaporator in multiple different stages, including heating and cooling phases, including: When the evaporator temperature is in the first heating stage, the first heating stage is the stage when the evaporator temperature rises from the defrost fan start-up temperature threshold to the first temperature threshold. The speed of the defrost fan is controlled to increase from the minimum allowable speed until the evaporator temperature reaches the first temperature threshold. The speed of the defrost fan is gradually increased in units of a first speed value, where the first speed value is the speed increase of the defrost fan for each unit increase in evaporator temperature. When the evaporator temperature is in the second heating stage, the speed of the defrosting fan is controlled to continue to increase until the evaporator temperature reaches the maximum defrost temperature, which is greater than the first temperature threshold. The speed of the defrosting fan is gradually increased in units of a second speed value, which is the speed increase of the defrosting fan for each unit increase in the evaporator temperature. The second speed value is less than the first speed value. The change in evaporator temperature also includes a maintenance phase, which is located between the first heating phase and the second heating phase in time. During the second heating phase, the speed of the defrosting fan starts to increase from the speed of the defrosting fan at the end of the maintenance phase. The defrosting control method further includes: entering the maintenance phase when the evaporator temperature reaches the first temperature threshold, and controlling the defrosting fan to maintain a constant speed when the evaporator temperature is in the maintenance phase.

2. The defrosting control method according to claim 1, characterized in that, The method further includes controlling the speed of the defrosting fan according to the temperature change of the evaporator in multiple different stages of heating and cooling, and also includes: After the evaporator temperature reaches the maximum frost temperature, the process switches to the cooling phase. During the cooling phase, the speed of the defrosting fan is reduced. The speed of the defrosting fan begins to decrease at the end of the second heating stage. The speed of the defrosting fan gradually decreases in units of a third speed value, where the third speed value is the speed decrease of the defrosting fan for each unit temperature decrease of the evaporator temperature. The third speed value is greater than the first speed value.

3. The defrosting control method according to claim 2, characterized in that, The defrosting control method further includes: When the evaporator temperature reaches the second temperature threshold, the defrosting heating element is controlled to stop heating and the defrosting fan is controlled to continue running, wherein the second temperature threshold is less than the maximum defrosting temperature.

4. The defrosting control method according to claim 3, characterized in that, The defrosting control method further includes: The cumulative time the defrosting fan has continued to run since the defrosting heating element stopped heating is obtained; When the accumulated time reaches the first time threshold, the compressor is controlled to start and begin refrigeration operation.

5. The defrosting control method according to claim 4, characterized in that, The defrosting control method further includes: Record the duration of the compressor's cooling operation; When the compressor's cooling operation time reaches the second time threshold, the defrosting fan is stopped and the refrigeration fan is started.

6. The defrosting control method according to claim 3, characterized in that, The starting temperature threshold value of the defrosting fan satisfies: (-15℃) - T℃≤T 启 ≤ (-15℃) + T℃, T 启 The defrosting fan start-up temperature threshold is... T is the fluctuation tolerance limit; And / or, the second temperature threshold is lower than the conventional defrost exit temperature of the refrigeration and freezing device, the conventional defrost exit temperature being the defrost exit temperature set in the conventional defrost program of the refrigeration and freezing device, the conventional defrost program including: entering defrost mode, controlling the defrost heating element to start to heat the evaporator, and when the temperature of the evaporator surface rises to the defrost exit temperature, turning off the defrost heating element and exiting the defrost mode.

7. A refrigeration and freezing apparatus, characterized in that, The refrigeration and freezing apparatus includes: The air duct includes a front cover plate, a rear cover plate, and an inner liner for a refrigeration and freezing device. The front cover plate and the rear cover plate form an air duct, and the rear cover plate and the inner liner for the refrigeration and freezing device form an evaporator compartment. The rear cover plate has an air inlet. A refrigeration circuit, comprising a compressor, an evaporator, a throttling device, and a condenser, wherein the evaporator is located in the evaporator compartment; A cooling fan is located in the air duct and is disposed at the air inlet. It is used to rotate in a second rotation direction in the cooling mode to transfer the cooling capacity of the evaporator to the storage room through the air inlet and the air duct. A defrosting fan is located in the evaporator compartment and is disposed at the air inlet; Temperature sensor, used to detect evaporator temperature; A defrosting heating element, wherein the defrosting heating element is located inside the evaporator compartment; A controller, connected to the temperature sensor, the defrosting heating element, the compressor, the refrigeration fan, and the defrosting fan, is used to execute the defrosting control method according to any one of claims 1-6 in defrosting mode.

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