Refrigerator and its control method

Abstract

The present invention provides a refrigerator and a control method thereof. The refrigerator includes a box body, a first storage compartment is formed inside the box body, and further includes a high-temperature stage refrigeration cycle circuit and a low-temperature stage refrigeration cycle circuit; the high-temperature stage refrigeration cycle circuit includes a first evaporator and an evaporation part for absorbing heat, and the first evaporator is used for cooling the first storage compartment; the low-temperature stage refrigeration cycle circuit includes a condensation part and a second evaporator for absorbing heat, the condensation part is thermally connected to the evaporation part, and the second evaporator cools the first storage compartment by a direct cooling method. The refrigerator enables a single storage compartment to have a multi-temperature zone function, that is, the first storage compartment can obtain different refrigeration effects to meet different refrigeration needs and storage needs. The second evaporator cools the first storage compartment by a direct cooling method, which can prevent the second evaporator from frosting quickly. When frequent defrosting is required, the temperature fluctuation of the compartment is small, ensuring the food preservation effect.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration, and particularly to a refrigerator and a control method thereof. Background Art

[0002] At present, the temperature range of the variable-temperature compartment in refrigerators on the market is mostly adjusted between 8 - 18°C, and the overall design is relatively conventional. With the gradual improvement of people's living standards, such temperature-range refrigerators can no longer well meet everyone's needs. There is a need to design high-end refrigerators with a wider temperature range and more complete functions to meet more user needs. For the preservation of food in a vitreous state below -40°C, which is beneficial to maximizing the nutritional value of food, there is a demand for an ultra-low temperature compartment (-40 to -60°C) in the high-end user market. To improve user satisfaction and focus on the user experience. For this reason, a conventional cascade compression refrigeration system usually consists of two separate refrigeration cycle circuits, which are respectively called a high-temperature stage refrigeration cycle circuit (referred to as the high-temperature part) and a low-temperature stage refrigeration cycle circuit (referred to as the low-temperature part). The high-temperature part uses a first refrigerant with a relatively high evaporation temperature, and the low-temperature part uses a second refrigerant with a relatively low evaporation temperature. And a condensing evaporator is adopted, which uses the cold generated by the first refrigerant in the high-temperature part to condense the second refrigerant vapor discharged from the compressor in the low-temperature part, so as to achieve a low temperature below -60. However, in some existing cascade compression refrigeration systems, the high-temperature stage refrigeration cycle circuit is only used to supply cold to the condenser of the low-temperature stage refrigeration cycle circuit, resulting in low refrigeration efficiency of the cascade compression refrigeration system. Moreover, conventional cryogenic refrigerators only have a single temperature function, which also makes the system efficiency low. Summary of the Invention

[0003] In order to overcome at least one technical defect of the existing cryogenic refrigerators, the inventors of the present invention proposed to use an air-cooled evaporator for the cryogenic operation of the storage compartment. However, the inventors found that if the low-temperature system is set with an air-cooled evaporator, the compartment temperature is relatively low, and the evaporator frosts quickly. When defrosting, the surface temperature of the evaporator needs to be heated above 0°C, and the compartment temperature rise is relatively high, which cannot guarantee the food preservation effect. Based on this, the present invention proposes a novel refrigerator and a control method thereof.

[0004] On the one hand, the present invention provides a refrigerator, including a box body, a first storage compartment is formed inside the box body, and it further includes a high-temperature stage refrigeration cycle circuit and a low-temperature stage refrigeration cycle circuit;

[0005] The high-temperature stage refrigeration cycle circuit includes a first evaporator for absorbing heat and an evaporation part, and the first evaporator is used to supply cold to the first storage compartment;

[0006] The low-temperature refrigeration cycle circuit includes a condensation part and a second evaporator for absorbing heat. The condensation part is thermally connected to the evaporation part, and the second evaporator cools the first storage compartment by direct cooling.

[0007] Optionally, the box body includes an inner container, and the first storage compartment is provided inside the inner container; the second evaporator is arranged on the outer wall of the inner container.

[0008] Optionally, the second evaporator includes evaporation tubes, and the evaporation tubes are wound around two side walls, a top wall and a bottom wall of the inner container; or,

[0009] The second evaporator is a tube-sheet evaporator and is arranged on two side walls, a top wall and a bottom wall of the inner container.

[0010] Optionally, the high-temperature refrigeration cycle circuit further includes a control valve which has a first outlet and a second outlet. The inlet of the evaporation part is communicated with the first outlet; the inlet of the first evaporator is communicated with the second outlet; the outlet of the first evaporator is communicated with the inlet of the evaporation part.

[0011] Optionally, a second storage compartment is further formed inside the box body; the high-temperature refrigeration cycle circuit further includes a third evaporator;

[0012] The third evaporator is used to cool the second storage compartment; the inlet of the third evaporator is communicated with the outlet of the evaporation part.

[0013] Optionally, a third storage compartment is further formed inside the box body; the high-temperature refrigeration cycle circuit further includes a fourth evaporator which is used to cool the third storage compartment, and the fourth evaporator is arranged between the inlet of the evaporation part and the first outlet;

[0014] The control valve has a third outlet, and the third outlet is communicated with the inlet of the third evaporator;

[0015] A first throttling device is arranged between the inlet of the fourth evaporator and the first outlet;

[0016] A second throttling device is arranged between the inlet of the first evaporator and the second outlet;

[0017] A third throttling device is arranged between the inlet of the third evaporator and the third outlet;

[0018] The first storage compartment and the second storage compartment are arranged in parallel along the transverse extension direction of the refrigerator, and the third storage compartment is arranged above the first storage compartment and the second storage compartment;

[0019] A valve that only allows the refrigerant from the second evaporator to flow out unidirectionally is provided on the outlet pipe of the first evaporator.

[0020] Optionally, the refrigerator further includes a air supply device to enable the first evaporator to supply cooling to the first storage compartment in an air-cooling manner, and when the refrigerator is in the deep-freezing mode where the second evaporator operates, the air supply device is turned on.

[0021] At a position corresponding to the rear side of the first storage compartment of the cabinet, a first refrigerating chamber for arranging the first evaporator is further formed. The first refrigerating chamber is communicated with the first storage compartment through a first air supply structure to provide a cooling air flow to the first storage compartment through the first air supply structure.

[0022] Optionally, at a position corresponding to the rear side of the second storage compartment of the cabinet, a second refrigerating chamber for arranging the third evaporator is further formed. The second refrigerating chamber is communicated with the second storage compartment through a second air supply structure to provide a cooling air flow to the second storage compartment through the second air supply structure.

[0023] The evaporation part and the condensation part are arranged in the second refrigerating chamber.

[0024] On the other hand, the present invention also provides a control method for a refrigerator. The refrigerator includes a cabinet, a high-temperature stage refrigeration cycle circuit and a low-temperature stage refrigeration cycle circuit. A first storage compartment is formed inside the cabinet. The high-temperature stage refrigeration cycle circuit includes a first evaporator and an evaporation part for absorbing heat. The first evaporator supplies cooling to the first storage compartment in an air-cooling manner. The low-temperature stage refrigeration cycle circuit includes a condensation part and a second evaporator for absorbing heat. The condensation part is thermally connected to the evaporation part. The second evaporator supplies cooling to the first storage compartment in a direct-cooling manner. Wherein, the control method includes:

[0025] When the refrigerator is in the deep-freezing mode where the second evaporator operates, detect the amount of frost formation in the first storage compartment.

[0026] When the amount of frost formation reaches a preset amount of frost formation, make the refrigerator be in the normal refrigeration mode where the first evaporator operates.

[0027] Optionally, the refrigerator further includes a air supply device to enable the first evaporator to supply cooling to the first storage compartment in an air-cooling manner, and when the refrigerator is in the deep-freezing mode where the second evaporator operates, the air supply device is turned on.

[0028] The refrigerator of the present invention and its control method. The high-temperature stage refrigeration cycle circuit includes a first evaporator, and the low-temperature stage refrigeration cycle circuit includes a second evaporator. Both the first evaporator and the second evaporator can supply cold to the first storage compartment, enabling the refrigerator to have a multi-temperature zone function in a single storage compartment, that is, the first storage compartment can obtain different refrigeration effects to meet different refrigeration and storage requirements, and can expand the temperature zone range of the first storage compartment. In other words, the refrigerator can have both deep cooling function and meet the energy-saving requirements of daily refrigeration. In particular, the second evaporator supplies cold to the first storage compartment by direct cooling, which can prevent the second evaporator from frosting quickly. When frequent defrosting is required, the temperature fluctuation in the compartment is small, ensuring the food preservation effect.

[0029] Furthermore, in the refrigerator and its control method of the present invention, the first evaporator and the second evaporator are separately arranged, which can prevent the temperatures of the two evaporators from affecting each other, and can also prevent the evaporators from being large in size and occupying a large space, resulting in a smaller storage space.

[0030] Furthermore, in the refrigerator and its control method of the present invention, when the first evaporator is working, that is, in the normal refrigeration mode, the refrigerator is an air-cooled product without the risk of frosting. When the user switches to the deep cooling mode with the second evaporator working, the second evaporator works by direct cooling and cooperates with the fan used when the first evaporator is working, which can not only cool down quickly but also refrigerate evenly. The refrigerator can operate for a long time with less frosting. When excessive frosting and icing occur in the compartment due to long-term operation in the deep cooling mode, the user can switch to the normal refrigeration mode, and the first evaporator for normal air cooling is used for refrigeration and defrosting. It can maintain low-temperature deep cooling operation for a long time to ensure long-term storage of food ingredients. At the same time, if defrosting is required, the residual frost layer in the compartment can be removed by the air-cooling system of the first evaporator, greatly improving the product use effect and user experience.

[0031] Furthermore, the layout positions of the evaporators and evaporation parts in the high-temperature stage refrigeration cycle circuit can ensure the refrigeration efficiency of each evaporator during normal refrigeration, improve the energy efficiency of the refrigerator, and the energy-saving effect is obvious. That is to say, the refrigerator can ensure the temperature control of each compartment when the high-temperature stage refrigeration cycle circuit operates independently to achieve the energy-saving purpose, and can also use the low-temperature stage refrigeration cycle circuit to realize the deep cooling function of the refrigerator. The second evaporator is wound around the two side walls, the top wall and the bottom wall of the inner liner, significantly improving the direct cooling efficiency.

[0032] Based on the following detailed description of the specific embodiments of the present invention in conjunction with the drawings, those skilled in the art will be more clear about the above and other purposes, advantages and features of the present invention. Description of the Drawings

[0033] Some specific embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings in an illustrative rather than restrictive manner. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0034] Figure 1 is a schematic diagram of a refrigerator according to an embodiment of the present invention;

[0035] Figure 2 is a schematic diagram of a refrigeration system in a refrigerator according to an embodiment of the present invention;

[0036] Figure 3 is a schematic diagram of a refrigeration system in a refrigerator according to an embodiment of the present invention;

[0037] Figure 4 is a schematic diagram of a partial structure of a refrigerator according to an embodiment of the present invention;

[0038] Figure 5 is a schematic sectional view of a partial structure of a refrigerator according to an embodiment of the present invention;

[0039] Figure 6 is a schematic diagram of a partial structure of a refrigerator according to an embodiment of the present invention. Detailed Embodiments

[0040] Figure 1 is a schematic diagram of a refrigerator according to an embodiment of the present invention. As Figure 1 shown, and referring to Figures 2 to 6 , an embodiment of the present invention provides a refrigerator, which may include a cabinet 20 and a refrigeration system. Among them, one or more storage compartments are further formed in the cabinet 20. In some embodiments, the storage compartment may include a first storage compartment 21. In some embodiments, the storage compartment may include a first storage compartment 21, a second storage compartment 22, and a third storage compartment 23. The refrigeration system may be disposed in the cabinet 20, and the refrigeration system includes a high-temperature stage refrigeration cycle loop 30 and a low-temperature stage refrigeration cycle loop 40. This refrigeration system may also be referred to as a cascade compression refrigeration system.

[0041] As Figure 2 and Figure 3As shown, the high-temperature refrigeration cycle circuit 30 is used for circulating the first refrigerant, and is provided therein with a first evaporator 36 for absorbing heat and an evaporation section 37. The first evaporator 36 is used to cause the first refrigerant flowing through it to absorb heat, and is used to cool the first storage compartment 21. The high-temperature refrigeration cycle circuit 30 further includes a high-temperature compressor 31 and a high-temperature condensing device 32. The low-temperature refrigeration cycle circuit 40 is used for circulating the second refrigerant, and is provided therein with a condensing section 42 and a second evaporator 44. Among them, the second evaporator 44 is used to cause the second refrigerant flowing through it to absorb heat, and is used to cool the first storage compartment 21. The low-temperature refrigeration cycle circuit 40 further includes a low-temperature compressor 41. The evaporation section 37 is used to cause the first refrigerant flowing through it to absorb the heat of the second refrigerant flowing through the condensing section 42 in the low-temperature refrigeration cycle circuit 40. The first refrigerant and the second refrigerant can be the same refrigerant, such as R600a, or different refrigerants.

[0042] Refrigerant, also known as refrigerant medium, usually completes energy conversion through phase change. It is a working substance that circulates in the refrigeration system of a refrigeration device. Its working principle is: the refrigerant absorbs the heat of the substance to be cooled in the evaporator and evaporates, and transfers the absorbed heat to the surrounding air or water in the condenser and is cooled into a liquid, and circulates reciprocally, achieving the refrigeration effect by means of state changes. The "high temperature" and "low temperature" in the "high-temperature refrigeration cycle circuit 30" and the "low-temperature refrigeration cycle circuit 40" are relative. Relatively speaking, the evaporation temperature of the first refrigerant flowing through the high-temperature refrigeration cycle circuit 30 is higher than the evaporation temperature of the second refrigerant flowing through the low-temperature refrigeration cycle circuit 40.

[0043] In the refrigerator according to the embodiment of the present invention, a first evaporator 36 is provided in the high-temperature refrigeration cycle circuit 30. The first evaporator 36 is used to cool the first storage compartment 21, and a second evaporator 44 is provided in the low-temperature refrigeration cycle circuit 40 for cooling the first storage compartment 21. The energy utilization efficiency in the high-temperature refrigeration cycle circuit 30 is improved, and the refrigeration efficiency of the refrigerator is improved. Both the first evaporator 36 and the second evaporator 44 can cool the first storage compartment 21, enabling a single storage compartment of the refrigerator to have a multi-temperature zone function, that is, the first storage compartment 21 can obtain different refrigeration effects to meet different refrigeration requirements, and can expand the temperature zone range of the first storage compartment 21. That is to say, the refrigerator can have both a deep cooling function and meet the energy-saving requirements of daily refrigeration. For example, through the first evaporator 36, the temperature of the first storage compartment 21 can be -18°C, and through the second evaporator 44, the temperature of the first storage compartment 21 can be -60°C.

[0044] Preferably, as Figure 4 and Figure 5As shown, in the embodiment of the present invention, the second evaporator 44 cools the first storage compartment 21 in a direct cooling manner. For example, the cabinet 20 includes an inner container, and the first storage compartment 21 is provided inside the inner container; the second evaporator 44 is disposed on the outer wall of the inner container. Specifically, the second evaporator 44 includes evaporation tubes, and the evaporation tubes are wound around two side walls, the top wall and the bottom wall of the inner container, and can adopt a spiral winding manner or other winding manners. Alternatively, the second evaporator 44 is a tube-in-plate evaporator and is disposed on two side walls, the top wall and the bottom wall of the inner container.

[0045] The second evaporator 44 cools the first storage compartment 21 in a direct cooling manner, which can prevent the second evaporator 44 from frosting quickly. When frequent defrosting is required, the temperature fluctuation in the compartment is small, ensuring the food preservation effect. It can maintain low-temperature deep cooling operation for a long time, ensuring long-term storage of food materials, and greatly improving the product use effect and user experience. The first evaporator 36 and the second evaporator 44 are separately arranged, which can prevent the temperatures of the two evaporators from affecting each other, and can also prevent the evaporators from being large in size and occupying a large space, resulting in a smaller storage space. The second evaporator 44 is wound around two side walls, the top wall and the bottom wall of the inner container, significantly improving the direct cooling efficiency.

[0046] In some embodiments of the present invention, the high-temperature stage refrigeration cycle circuit 30 further includes a control valve 33. The inlet of the control valve 33 can be communicated with the inlet of the high-temperature stage condensing device 32. The control valve 33 has a first outlet and a second outlet, the inlet of the first evaporator 36 is communicated with the second outlet; the inlet of the evaporation part 37 is communicated with the first outlet. The outlet of the first evaporator 36 is communicated with the inlet of the evaporation part 37. The control valve 33 can be a switching valve.

[0047] In some embodiments of the present invention, as Figure 2 and Figure 3 shown, the high-temperature stage refrigeration cycle circuit further includes a third evaporator 35. The third evaporator 35 is used to cool the second storage compartment 22; the inlet of the third evaporator 35 is communicated with the outlet of the evaporation part 37. In some embodiments of the present invention, as Figure 3 shown, the high-temperature stage refrigeration cycle circuit further includes a fourth evaporator 38. The fourth evaporator 38 is used to cool the third storage compartment 23, and the fourth evaporator 38 is disposed between the inlet of the evaporation part 37 and the first outlet. The layout positions of the various evaporators and the evaporation part 37 in the high-temperature stage refrigeration cycle circuit can ensure the refrigeration efficiency of each evaporator during normal refrigeration, improve the energy efficiency of the refrigerator, and the energy-saving effect is obvious. That is to say, this refrigerator can ensure the temperature control of each compartment when the high-temperature stage refrigeration cycle circuit 30 operates alone, achieving the purpose of energy saving, and can also utilize the low-temperature stage refrigeration cycle circuit 40 to realize the deep cooling function of the refrigerator.

[0048] In some embodiments of the present invention, the control valve 33 has a third outlet. The third outlet communicates with the inlet of the third evaporator 35. A first throttling device 343 is provided between the inlet of the fourth evaporator 38 and the first outlet; a second throttling device 342 is provided between the inlet of the first evaporator 36 and the second outlet; a third throttling device 341 is provided between the inlet of the third evaporator 35 and the third outlet. In some alternative embodiments, a total throttling device may be provided at the inlet of the control valve 33. Further, the first throttling device 343, the second throttling device 342, and the third throttling device 341 may all be capillary tubes. Optionally, the first throttling device 343, the second throttling device 342, and the third throttling device 341 may all be electromagnetic expansion valves. Then the control valve 33 may be selected as a multi-outlet diverter valve at this time.

[0049] In some embodiments of the present invention, as Figure 1 shown, the first storage compartment 21 and the second storage compartment 22 are arranged side by side along the lateral extension direction of the refrigerator, and the third storage compartment 23 is arranged above the first storage compartment 21 and the first storage compartment 21. The second storage compartment 22 may be a freezer compartment, the first storage compartment 21 is a multi-temperature functional compartment, and the third storage compartment 23 may be a refrigerating compartment. Such an arrangement can make the compartment layout more reasonable and make it more convenient to access corresponding items.

[0050] In some embodiments of the present invention, as Figure 4 and Figure 5 shown, the refrigerator further includes a blowing device 50 to enable the first evaporator 36 to supply cold air to the first storage compartment 21 in an air-cooling manner, that is to say, the blowing device 50 is used to promote the air flow to flow through the first evaporator 36 and enter the first storage compartment 21. Preferably, when the refrigerator is in the deep cooling mode in which the second evaporator 44 operates, the blowing device 50 is turned on.

[0051] In this embodiment, when the first evaporator 36 is operating, that is, in the normal refrigeration mode, the refrigerator is an air-cooled product without the risk of frosting. When the user switches to the deep cooling mode in which the second evaporator 44 operates, the second evaporator 44 operates in a direct cooling manner and cooperates with the blower 50 used when the first evaporator 36 operates, which can not only quickly reduce the temperature but also uniformly refrigerate. The refrigerator can operate for a long time with less frosting. When too much frosting and icing occurs in the compartment due to the long-term operation of the deep cooling mode, the user can switch to the normal refrigeration mode and defrost by the first evaporator 36 with normal air cooling. It can maintain low-temperature deep cooling operation for a long time to ensure the long-term storage of food ingredients. At the same time, if defrosting is required, the residual frost layer in the compartment can be removed by the air-cooling system of the first evaporator 36, which greatly improves the product use effect and user experience.

[0052] Further, a first refrigeration chamber 24 for arranging a first evaporator 36 is formed at a position corresponding to the rear side of the first storage chamber 21 of the box body 20. The first refrigeration chamber 24 communicates with the first storage chamber 21 through a first air supply structure 51, and a refrigeration air flow is supplied to the first storage chamber 21 through the first air supply structure 51.

[0053] In some embodiments of the present invention, as Figure 1 and Figure 6 shown, a second refrigeration chamber for arranging a third evaporator 35 is further formed at a position corresponding to the rear side of the second storage chamber 22 of the box body 20. The second refrigeration chamber communicates with the second storage chamber 22 through a second air supply structure 52, so as to supply a refrigeration air flow to the second storage chamber 22 through the second air supply structure 52. A third refrigeration chamber for arranging a fourth evaporator 38 is further formed at a position corresponding to the rear side of the third storage chamber 23 of the box body 20. The third refrigeration chamber communicates with the third storage chamber 23 through a third air supply structure, so as to supply a refrigeration air flow to the third storage chamber 23 through the third air supply structure.

[0054] The first air supply structure is arranged between the first refrigeration chamber 24 and the first storage chamber 21; an air inlet is arranged on the rear side surface of the first air supply structure 51, and the air supply device 50 is arranged at the air inlet. A plurality of air outlets 54 are arranged on the front side surface of the first air supply structure 51, and an air supply air duct 55 is arranged in the first air supply structure 51. A return air duct 56 can be arranged on the lower side of the first air supply structure to realize air supply from the bottom and air outlet from the top of the evaporator. The second air supply structure and the third air supply structure are both similar to the first air supply structure 51.

[0055] A valve that only allows the refrigerant from the first evaporator 36 to flow out unidirectionally is provided on the outlet pipe of the first evaporator 36. This valve can be a check valve 39, and the check valve 39 can prevent the first refrigerant downstream of the check valve 39 from flowing backward. When the low-stage compressor 41 operates, the temperature of the second evaporator 44 is very low. The low temperature in the first storage room 21 will make the pipeline temperature of the first evaporator 36 relatively low, and even significantly lower than the temperature of other evaporators downstream of the first evaporator 36 in the high-stage refrigeration cycle circuit 30. This valve can prevent the first refrigerant in other cooling evaporators downstream of the first evaporator 36 from flowing into the first evaporator 36 from the discharge port of the first evaporator 36, thereby avoiding the reverse flow of the first refrigerant in the high-stage refrigeration cycle circuit 30, ensuring the effective flow rate of the first refrigerant, and improving the overall refrigeration efficiency. That is, it can prevent the first refrigerant in the high-stage refrigeration cycle circuit from gradually accumulating in the first evaporator 36, the refrigerant in the high-stage refrigeration cycle circuit gradually decreases, and the refrigeration is poor. The check valve 39 can prevent the refrigerant from flowing backward and accumulating in the first evaporator 36, resulting in poor refrigeration. Through the check valve 39, there is no need to control the program to adjust the operation of the valve body, and the problem of refrigerant accumulation caused by low temperature can be solved. The structure is simple and the operability is strong.

[0056] The high-stage condensing device 32 may include a condenser and a dew-proof pipe. The low-stage refrigeration cycle circuit 40 further includes a low-stage condensing device 45 and a low-stage throttling device 43. The inlet of the high-stage condensing device 32 is connected to the outlet of the high-stage compressor 31, and the outlet of the third evaporator 35 is connected to the inlet of the high-stage compressor 31. The outlet of the low-stage compressor 41 is connected to the inlet of the low-stage condensing device 45, the outlet of the low-stage condensing device 45 is connected to the inlet of the condensing part 42, the outlet of the condensing part 42 is connected to the low-stage throttling device 43, the outlet of the low-stage throttling device 43 is connected to the inlet of the second evaporator 44, and the outlet of the second evaporator 44 is connected to the inlet of the low-stage compressor 41.

[0057] In some alternative embodiments, the condensation part 42 and the evaporation part 37 can form a condensation-evaporator. The condensation-evaporator can be a double-pipe heat exchanger. A double-pipe heat exchanger is formed by sleeving and connecting two standard pipes of different sizes to form concentric circular sleeves. The outer channel is called the shell side, and the inner channel is called the tube side. Two different media can flow in opposite (or the same) directions in the shell side and the tube side to achieve the heat exchange effect. The evaporation part 37 can be the tube side, and the condensation part 42 can be the shell side. In some other alternative embodiments, the condensation part 42 and the evaporation part 37 can also be two copper pipes that are abutted against each other. The two copper pipes are arranged to be abutted against each other. At the contact part between the two copper pipes, soldering can be used for fixation to enhance heat transfer. The outsides of the two copper pipes can be wrapped with aluminum foil. In some other alternative embodiments, the condensation part 42 and the evaporation part 37 can share heat exchange fins. The evaporation part 37 and the condensation part 42 are arranged in the second refrigeration chamber. Of course, the evaporation part 37 and the condensation part 42 can also be arranged at other positions of the refrigerator.

[0058] An embodiment of the present invention further provides a control method for a refrigerator. The refrigerator includes a box body 20, a high-temperature-stage refrigeration cycle circuit 30, and a low-temperature-stage refrigeration cycle circuit 40. A first storage compartment 21 is formed inside the box body 20. The high-temperature-stage refrigeration cycle circuit includes a first evaporator 36 for absorbing heat and an evaporation part 37. The first evaporator 36 cools the first storage compartment 21 by means of air cooling. The low-temperature-stage refrigeration cycle circuit 40 includes a condensation part 42 and a second evaporator 44 for absorbing heat. The condensation part 42 is thermally connected to the evaporation part 37. The second evaporator 44 cools the first storage compartment 21 by means of direct cooling. Specifically, the control method includes: when the refrigerator is in the deep-freezing mode in which the second evaporator 44 operates, detecting the amount of frost formation in the first storage compartment 21. When the amount of frost formation reaches a preset amount of frost formation, the refrigerator is put into the normal refrigeration mode in which the first evaporator 36 operates. Further, the control method of the refrigerator further includes turning on the air supply device 50 when the refrigerator is in the deep-freezing mode in which the second evaporator 44 operates.

[0059] In the control method of the refrigerator according to the embodiment of the present invention, when the first evaporator 36 operates, that is, in the normal refrigeration mode, the refrigerator is an air-cooled product and there is no risk of frost formation. When the user switches to the deep-freezing mode in which the second evaporator 44 operates, the second evaporator 44 operates by direct cooling and cooperates with the fan used when the first evaporator 36 operates, so that the temperature can be quickly reduced and the refrigeration can be uniform. The refrigerator can operate for a long time and has less frost formation. When the deep-freezing mode operates for a long time and causes excessive frost formation and icing in the compartment, the user can switch to the normal refrigeration mode and cool and defrost through the normally air-cooled first evaporator 36. The low-temperature deep-freezing operation can be maintained for a long time to ensure the long-term storage of food ingredients. At the same time, if defrosting is required, the residual frost layer in the compartment can be removed through the air-cooling system of the first evaporator 36, which greatly improves the use effect of the product and the user experience.

[0060] At this point, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived from the disclosed content of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A refrigerator, comprising a box body, wherein a first storage compartment is formed inside the box body, and is characterized in that, It further includes a high-temperature stage refrigeration cycle loop and a low-temperature stage refrigeration cycle loop; The high-temperature stage refrigeration cycle loop includes a first evaporator and an evaporation part for heat absorption, and the first evaporator is used to supply cold air to the first storage compartment; The low-temperature stage refrigeration cycle loop includes a condensation part and a second evaporator for heat absorption. The condensation part is thermally connected to the evaporation part, and the second evaporator supplies cold air to the first storage compartment by means of direct cooling; The refrigerator further includes a blowing device, so that the first evaporator supplies cold air to the first storage compartment by means of air cooling, and the blowing device is turned on when the refrigerator is in the deep cooling mode in which the second evaporator operates; At a position corresponding to the rear side of the first storage compartment of the box body, a first refrigeration chamber for arranging the first evaporator is further formed. The first refrigeration chamber is communicated with the first storage compartment through a first air supply structure, so as to provide a refrigerating air flow to the first storage compartment through the first air supply structure; The high-temperature stage refrigeration cycle loop further includes a control valve. The control valve has a first outlet and a second outlet. The inlet of the evaporation part is communicated with the first outlet; the inlet of the first evaporator is communicated with the second outlet; the outlet of the first evaporator is communicated with the inlet of the evaporation part; A second storage compartment is further formed inside the box body; the high-temperature stage refrigeration cycle loop further includes a third evaporator; The third evaporator is used to supply cold air to the second storage compartment; the inlet of the third evaporator is communicated with the outlet of the evaporation part.

2. The refrigerator according to claim 1, wherein The box body includes an inner container, and the first storage compartment is provided inside the inner container; the second evaporator is arranged on the outer wall of the inner container.

3. The refrigerator according to claim 2, wherein The second evaporator includes evaporation tubes, and the evaporation tubes are wound around two side walls, a top wall and a bottom wall of the inner container; or, The second evaporator is a tube-plate evaporator and is arranged on two side walls, a top wall and a bottom wall of the inner container.

4. The refrigerator according to claim 1, wherein A third storage compartment is further formed inside the box body; the high-temperature stage refrigeration cycle loop further includes a fourth evaporator, and the fourth evaporator is used to supply cold air to the third storage compartment. The fourth evaporator is arranged between the inlet of the evaporation part and the first outlet; The control valve has a third outlet, and the third outlet is communicated with the inlet of the third evaporator; A first throttling device is arranged between the inlet of the fourth evaporator and the first outlet; A second throttling device is arranged between the inlet of the first evaporator and the second outlet; A third throttling device is arranged between the inlet of the third evaporator and the third outlet; The first storage compartment and the second storage compartment are arranged in parallel along the transverse extension direction of the refrigerator, and the third storage compartment is arranged above the first storage compartment and the second storage compartment; A valve that only allows the refrigerant from the second evaporator to flow out unidirectionally is arranged on the outlet pipe of the first evaporator.

5. The refrigerator according to claim 1, wherein At a position corresponding to the rear side of the second storage compartment in the box body, a second refrigerating chamber for arranging the third evaporator is further formed. The second refrigerating chamber is communicated with the second storage compartment through a second air supply structure, so as to supply a refrigerating air flow to the second storage compartment through the second air supply structure; The evaporation part and the condensation part are arranged in the second refrigerating chamber.

6. A control method for a refrigerator, characterized in that, Applied to the refrigerator according to any one of claims 1-5, the refrigerator includes a box body, a high-temperature refrigeration cycle circuit and a low-temperature refrigeration cycle circuit. A first storage compartment is formed inside the box body. The high-temperature refrigeration cycle circuit includes a first evaporator and an evaporation part for absorbing heat. The first evaporator cools the first storage compartment by air cooling; the low-temperature refrigeration cycle circuit includes a condensation part and a second evaporator for absorbing heat. The condensation part is thermally connected to the evaporation part. The second evaporator cools the first storage compartment by direct cooling. Wherein, the control method includes: When the refrigerator is in the deep cooling mode in which the second evaporator operates, detecting the frosting amount in the first storage compartment; When the frosting amount reaches a preset frosting amount, making the refrigerator be in the normal refrigeration mode in which the first evaporator operates.

7. The control method of the refrigerator according to claim 6, characterized in that, The refrigerator further includes a blowing device, so that the first evaporator cools the first storage compartment by air cooling, and when the refrigerator is in the deep cooling mode in which the second evaporator operates, the blowing device is turned on.

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