Evaporator defrosting system and defrosting control method

Abstract

The invention relates to an evaporator defrosting system and a defrosting control method. The system is applied to the refrigeration equipment with a compressor, the system comprises an evaporation coil, a liquid storage device, the compressor, a heater and a controller, and the liquid storage device comprises an upper connecting port and a lower connecting port; an outlet of the evaporation coil is configured to be connected to the upper connector from the upper part of the liquid storage device; the compressor is connected to an inlet of the evaporation coil and used for providing power for refrigerant circulation. The heater is arranged around or below the body of the evaporation coil; the controller is used for controlling the heater to heat the evaporation coil, so that the liquid refrigerant generates bubbles with liquid in a pipe opening of the evaporation coil; and controlling the compressor to extract the liquid-carrying bubbles accumulated at the pipe orifice of the evaporation coil pipe.

Description

Technical Field

[0001] This application relates to the field of evaporators, and in particular to an evaporator defrosting system and a defrosting control method. Background Art

[0002] As a key component in the refrigeration system, the evaporator mainly consists of an evaporator body and heating pipes. In its daily function, the evaporator cools the air by allowing the air to flow through itself, and then sends the cooled air into the device to achieve the purpose of reducing the temperature inside the device. However, the presence of moist air in this process brings a thorny problem. Since when the moist air flows through the low-temperature evaporator surface, water vapor will condense and sublime, thus frosting on the evaporator surface.

[0003] The frosting phenomenon has a significant negative impact on the refrigeration effect of the evaporator. The continuous accumulation of the frost layer will increase the thermal resistance, hinder the heat exchange between the evaporator and the air, and cause a significant drop in the refrigeration efficiency of the evaporator. To solve this problem, the prior art has introduced a heater. The function of the heater is to work regularly, generate heat to melt the frost layer on the evaporator surface, and maintain the normal refrigeration performance of the evaporator.

[0004] From the design consideration, since the heater has a short working time and a long interval time, the prior art excludes the somatic sensation test during defrosting from the design inspection indicators. However, with the improvement of living standards, users' requirements for the use experience of devices such as refrigerators are increasing day by day. Users feedback that there is a continuous "gurgling" sound inside the refrigerator, and the frequency and loudness of the "gurgling" sound are relatively high, which interferes with the living life. Summary of the Invention

[0005] This application provides a defrosting control method and an evaporator defrosting system to solve the technical problem of the relatively high frequency and loudness of the "gurgling" sound during the defrosting process of the evaporator coil in the above prior art.

[0006] The present invention provides an evaporator defrosting system, which is applied to a refrigeration device with a compressor. The evaporator defrosting system includes: an evaporator coil, a liquid receiver, a compressor, a heater, and a controller. Among them, the liquid receiver includes an upper connection port and a lower connection port; the outlet of the evaporator coil is configured to be connected to the upper connection port above the liquid receiver; the compressor is connected to the inlet of the evaporator coil to provide power for the refrigerant cycle; the heater is arranged around or below the body of the evaporator coil; the controller is used to control the heater to heat the evaporator coil so as to generate liquid-carrying bubbles in the pipe orifice of the evaporator coil, and control the compressor to extract the liquid-carrying bubbles accumulated at the pipe orifice of the evaporator coil.

[0007] Among them, the outlet area of the evaporation coil is configured such that a straight pipe section is bent once to obtain a U-shaped pipe. One end of the U-shaped pipe is communicated with the body of the evaporation coil, and the other end of the U-shaped pipe is configured as the outlet.

[0008] Among them, the outlet of the U-shaped pipe is configured as a gradually expanding port.

[0009] Among them, the defrosting system of the evaporator includes a transition pipe. The transition pipe includes a transition inlet and a transition outlet. The transition inlet is connected to the lower connection port. The transition outlet is arranged towards the body of the evaporation coil, and the horizontal position of the transition outlet is lower than the horizontal position of the lower connection port.

[0010] Among them, the transition pipe includes a first U-shaped part and a second U-shaped part. The first U-shaped part is communicated with the second U-shaped part and is arranged in central symmetry.

[0011] Among them, the top surface of one of the first U-shaped part and the second U-shaped part is flush with the top surface of the U-shaped pipe.

[0012] The present invention also provides a defrosting control method, and the method includes:

[0013] Controlling the heater to start with a first power to heat the evaporation coil so that liquid refrigerant generates liquid-carrying bubbles in the pipe orifice of the evaporation coil;

[0014] Determining that the start of the heater satisfies a first preset time, and controlling the heater to stop heating;

[0015] Controlling the compressor to start at a preset frequency to extract the liquid-carrying bubbles accumulated at the pipe orifice of the evaporation coil. The preset frequency is less than the first power;

[0016] Determining that the start of the compressor satisfies a second preset time, and controlling the compressor to stop operating;

[0017] Repeating the above process until the liquid refrigerant meets the preset conditions.

[0018] Among them, the preset conditions include at least one of the following: the sum of the multiple first preset times of multiple starts of the heater is equal to a first preset time value; or

[0019] Determining that the liquid refrigerant in the evaporation coil is completely vaporized; or

[0020] Determining that the liquid-carrying amount of bubbles in the evaporation coil is lower than a preset amount value; or

[0021] Determining that the generation rate of the liquid-carrying bubbles meets a preset rate range.

[0022] The first power, the first preset time, the preset frequency and the second preset time all adopt constant values.

[0023] In the process of multiple starts, the first preset time gradually decreases; or, when the bubble generation rate increases, the first preset time gradually increases.

[0024] Before the step of controlling the heater to start at the first power to heat the evaporating coil so that the liquid refrigerant generates liquid bubbles in the pipe opening of the evaporating coil, the method includes:

[0025] Make sure the refrigeration equipment is in the defrost cycle and control the compressor to stop running.

[0026] Wherein, after determining that the refrigeration equipment is in a defrosting cycle and controlling the compressor to stop running, the method includes:

[0027] The heater is controlled to start at a second power to heat the evaporation coil.

[0028] The starting power of the second power is greater than the first power.

[0029] Among them, during multiple startup processes, the change of the first power when the heater is started is positively correlated with the bubble generation rate.

[0030] Wherein, after the step of repeating the above process until the liquid refrigerant meets the preset conditions, the method includes:

[0031] The heater is controlled to start at a third power to heat the corresponding evaporating coil, and the third power satisfies a trend of gradually increasing power.

[0032] Wherein, the starting power of the third power is greater than the first power.

[0033] Wherein, after the step of repeating the above process until the liquid refrigerant meets the preset conditions, the method includes:

[0034] Make sure the refrigeration equipment meets the conditions for exiting defrost, control the heater to shut down, and control the compressor to enter the refrigeration cycle.

[0035] Wherein, the defrost exit condition includes: the total time that the heater is continuously started is greater than or equal to a second preset time value, and the second preset time value is greater than the first preset time value.

[0036] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0037] The defrost control method and evaporator defrost system provided by the embodiments of the present application, based on the structural design of the evaporator defrost system, the outlet area of the evaporator coil adopts a U-shaped tube structure, and the outlet is connected to the upper connection port from above the liquid receiver, which changes the flow direction of the refrigerant entering the liquid receiver. Compared with the traditional connection method, this design enables the refrigerant to enter the liquid receiver at a specific path and angle, avoiding the refrigerant directly impacting the inner wall of the liquid receiver or forming a turbulent flow field, and reducing the noise generated by fluid impact and disturbance. Further, the controller can control the heater to heat the evaporator coil, so that liquid refrigerant can generate liquid bubbles with gas in the pipe orifice of the evaporator coil; and, the controller can control the compressor to extract the liquid bubbles with gas accumulated at the pipe orifice of the evaporator coil, so that the liquid bubbles with gas are extracted in time, which can avoid small bubbles aggregating at the pipe orifice to form large bubbles and generating a "gurgling" sound.

[0038] Based on the defrost control method, the compressor starts at intervals to timely draw back the gaseous refrigerant. During the operation of the system, a certain amount of gaseous refrigerant will accumulate in the liquid receiver. If these gaseous refrigerants cannot be discharged in time, pressure fluctuations will be formed in the liquid receiver, which will in turn lead to the generation of abnormal sounds such as "gurgling" sounds. The compressor starts at intervals to draw back the gaseous refrigerant, which can effectively control the amount of gaseous refrigerant in the liquid receiver, maintain the relative stability of the pressure in the liquid receiver, thereby reducing phenomena such as liquid sloshing and bubble rupture caused by pressure fluctuations, and also reducing the generation of noise. When the gaseous refrigerant is drawn back in time, the pressure and flow distribution in the system are more uniform, the operation of the entire system is more stable, and abnormal sounds can be effectively suppressed or even completely eliminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings here are incorporated into the specification and form a part of this specification, showing the embodiments in line with the present invention, and are used together with the specification to explain the principles of the present invention.

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, unless otherwise stated, and the drawings in the drawings do not constitute a proportional limitation.

[0042] Figure 1 Structural schematic of the evaporator defrost system provided by the embodiments of the present application Figure 1 ;

[0043] Figure 2 Structural schematic of the evaporator defrosting system provided by the embodiment of the present application Figure 2 ;

[0044] Figure 3 is Figure 2 structural schematic of the U-shaped tube in

[0045] Figure 4 Flowchart of the defrosting control method provided by the embodiment of the present application

[0046] Explanation of reference numerals:

[0047] 1, evaporation coil; 11, U-shaped tube; 111, outlet; 2, liquid storage tank; 21, upper connection port; 22, lower connection port; 111A, gradually expanding port; 3, transition pipe; 31, transition inlet; 32, transition air outlet; 3A, first U-shaped part; 3B, second U-shaped part; 4, compressor; 5, condenser; 6, dryer; 7, capillary tube (return air heat exchange section). Detailed implementation manners

[0048] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0049] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0050] For ease of description, spatial relative terms may be used in the text to describe the relative positional relationship or movement of one element or feature shown in the figure with respect to another element or feature. These relative terms include, for example, "inside", "outside", "inner side", "outer side", "below", "beneath", "above", "over", "front", "rear", etc. Such spatial relative terms are intended to include different orientations of the device during use or operation in addition to the orientations depicted in the figure. For example, if the device in the figure undergoes a position flip, attitude change, or change in motion state, then these directional indications will change accordingly. For example, an element described as "below" or "beneath" other elements or features will subsequently be oriented as "above" or "over" other elements or features. Therefore, the exemplary term "below" can include both upward and downward orientations. The device can be oriented otherwise (rotated 90 degrees or in other directions), and the spatial relative descriptions used in the text have been interpreted accordingly.

[0051] An evaporator is a key component in a refrigeration system that achieves the refrigeration effect. Its function is to allow the refrigerant to evaporate and absorb heat therein, reducing the temperature of the surrounding medium (such as air, water, etc.) to achieve the purpose of refrigeration. The specific process is that the low-temperature and low-pressure refrigerant liquid enters the evaporator, absorbs heat and evaporates inside the evaporator, becoming a low-temperature and low-pressure refrigerant gas, while absorbing the heat of the surrounding medium to cool the surrounding environment.

[0052] The evaporator component mainly consists of an evaporator and heating tubes. After the air flows through the evaporator and is cooled, it is sent to the equipment to reduce the temperature. However, moist air will frost on the surface of the evaporator, affecting the refrigeration effect. Therefore, the heater needs to work regularly to defrost the surface of the evaporator. During the process of moist air frosting on the surface of the evaporator and the heater working regularly to defrost, a "gurgling" sound will be generated, which has reached the level of disturbing the residents.

[0053] Regarding the phenomenon of the "gurgling" sound occurring during the defrosting process of the evaporator, from the perspective of the evaporator structure, it may be that during the defrosting process of the heating tubes, due to uneven heating or structural defects at the connection part between the heating tubes and the evaporator body, local abnormal thermal expansion and contraction are caused, which in turn triggers this "gurgling" sound. From the perspective of daily functions, when the heater starts and shuts down, the temperature and pressure inside the evaporator will change rapidly. This change may cause the unstable flow state of the refrigerant inside the evaporator, resulting in abnormal sounds. In the design of the prior art, perhaps only the defrosting function of the heater was concerned, while ignoring these possible structural and functional side effects during its operation, which is the problem existing in the prior art.

[0054] To alleviate the above problems, refer to Figures 1 - 4, embodiments of the present application provide a defrost control method and an evaporator defrost system, which can start from both the electronic control method and the physical structure. That is, by changing the flow direction of the refrigerant entering the liquid receiver 2 and using the compressor 4 to start intermittently to timely draw back the gaseous refrigerant, the frequency and loudness of the "gurgling" sound can be reduced, and even the abnormal sound can be completely eliminated.

[0055] The evaporator defrost system provided by the embodiments of the present application includes: an evaporation coil 1, a liquid receiver 2, a compressor 4, a heater, and a controller. Among them, the liquid receiver 2 includes an upper connection port 21 and a lower connection port 22; the outlet 111 is configured to be connected to the upper connection port 21 above the liquid receiver 2; the compressor 4 is connected to the inlet of the evaporation coil 1 to provide power for the refrigerant circulation; the heater is arranged around or below the body of the evaporation coil 1; the controller is used to control the heater to heat the evaporation coil 1 so that the liquid refrigerant generates liquid-carrying bubbles in the pipe orifice of the evaporation coil 1; and, control the compressor 4 to draw out the liquid-carrying bubbles accumulated at the pipe orifice of the evaporation coil 1.

[0056] In this way, the liquid refrigerant can generate liquid-carrying bubbles in the pipe orifice of the evaporation coil 1; and, the controller can control the compressor 4 to draw out the liquid-carrying bubbles accumulated at the pipe orifice of the evaporation coil 1. In this way, the liquid-carrying bubbles are drawn out in time, which can avoid the aggregation of small bubbles at the pipe orifice to form large bubbles and generate the "gurgling" sound.

[0057] Considering the specific structural composition of the evaporation coil 1, in the evaporator defrost system provided by the embodiments of the present application, the outlet 111 area of the evaporation coil 1 is configured to obtain a U-shaped pipe 11 through a single bend via a straight pipe section. One end of the U-shaped pipe 11 is communicated with the body of the evaporation coil 1, and the other end of the U-shaped pipe 11 is configured as the outlet 111.

[0058] In this way, the outlet 111 area of the evaporation coil 1 adopts the U-shaped pipe 11 structure, and the outlet 111 is connected from above the liquid receiver 2 to the upper connection port 21, which changes the flow direction of the refrigerant entering the liquid receiver 2. Compared with the traditional connection method, this design enables the refrigerant to enter the liquid receiver 2 at a specific path and angle, avoiding the direct impact of the refrigerant on the inner wall of the liquid receiver 2 or forming a disordered flow field, and reducing the noise generated by fluid impact and disturbance. Further, combined with the controller, the heater can be controlled to heat the evaporation coil 1. In this way, the liquid refrigerant can generate liquid-carrying bubbles in the pipe orifice of the evaporation coil 1; and, the controller can control the compressor 4 to draw out the liquid-carrying bubbles accumulated at the pipe orifice of the evaporation coil 1. In this way, the liquid-carrying bubbles are drawn out in time, which can avoid the aggregation of small bubbles at the pipe orifice to form large bubbles and generate the "gurgling" sound.

[0059] Exemplarily, the accumulator 2 is an important component of the compressor 4, which functions to store, separate gas and liquid, filter, suppress noise, and buffer the refrigerant. Exemplarily, the accumulator 2 generally includes a cylinder body, which is usually made of SPCC deep-drawing steel plate. The size determines the liquid storage volume, and the wall thickness is related to the diameter.

[0060] The evaporation coil 1 also includes an inlet region, which is mainly used for the entry of liquid refrigerant. The outside of the evaporation coil 1 usually exchanges heat with a low-temperature heat source (such as air, water, etc.). After the liquid refrigerant enters the evaporation coil 1, since its temperature is lower than that of the surrounding medium and the pressure is relatively low, it will absorb the heat of the surrounding medium.

[0061] During the heat absorption process, the liquid refrigerant begins to evaporate and gradually changes from a liquid state to a gaseous state. In this process, the internal energy of the refrigerant increases, the temperature remains basically unchanged, but the state changes. As the heat absorption progresses, the liquid refrigerant continuously evaporates, forming a state of coexistence of gas and liquid in the evaporation coil 1. Due to the space and flow characteristics in the evaporation coil 1, the evaporation process of the refrigerant is not uniform. In the area near the inlet region, there is relatively more liquid refrigerant, and as the refrigerant flows in the coil, the proportion of gaseous refrigerant gradually increases.

[0062] When the refrigerant flows to the outlet 111 region of the evaporation coil 1, since the evaporation process is not yet complete, the refrigerant at this time is in a gas-liquid mixed state. This is because in actual operation, in order to ensure the heat exchange effect of the evaporator and the stability of the system, the refrigerant is not allowed to completely evaporate into a gaseous state in the evaporator, but a certain proportion of liquid refrigerant is retained to better control the flow rate and pressure of the refrigerant in the subsequent refrigeration cycle.

[0063] Through the above process, the evaporation coil 1 realizes the function of absorbing heat from the low-temperature heat source and converting the liquid refrigerant into a gas-liquid mixed refrigerant, providing the necessary conditions for the subsequent compression of the gaseous refrigerant by the compressor 4 and the refrigeration or heating cycle of the entire heat pump unit.

[0064] Considering the specific connection scheme between the outlet 111 region of the evaporation coil 1 and the connection port 21 on the accumulator 2, in the evaporator defrosting system provided by the embodiments of the present application, the outlet 111 of the U-shaped tube 11 is configured as a gradually expanding port 111A.

[0065] Exemplarily, the gradually expanding port 111A has a gradually increasing caliber size in the direction from the outlet 111 towards the upper connection port 21.

[0066] In this way, the vapor-liquid mixed refrigerant flowing out of the evaporation coil 1 can achieve a gradual reduction in flow velocity through the gradually expanding port 111A, making the process of the refrigerant entering the liquid receiver 2 smoother. This is like a river flowing from a narrow area into a wide area, where the water flow becomes gentle, avoiding a sharp change in flow velocity caused by a sudden change in pipe diameter, reducing fluid impact and turbulence phenomena, and thus reducing the operating noise and making the system operation quieter. Further, the gradually expanding port 111A enables the refrigerant to be more evenly distributed when entering the liquid receiver 2. Since the diameter gradually increases, the difference in flow velocity at each position of the outlet 111 of the refrigerant decreases, avoiding the refrigerant concentrating on flowing to a certain area of the liquid receiver 2, which is beneficial to forming a stable vapor-liquid separation interface in the liquid receiver 2, making the gaseous refrigerant gather more smoothly in the upper part of the liquid receiver 2, and the liquid refrigerant concentrating in the lower part, creating favorable conditions for the subsequent efficient extraction of the gaseous refrigerant by the compressor 4.

[0067] In addition, the design of the gradually expanding port 111A increases the space volume of the vapor-liquid mixed refrigerant at the outlet 111. When the refrigerant flows through the gradually expanding port 111A, there is more space for the vapor-liquid two-phase to separate. Just like in a spacious container, substances with different densities are more likely to be stratified. The gaseous refrigerant has more opportunities to move upward, and the liquid refrigerant is more likely to precipitate downward, thus improving the vapor-liquid separation effect. At the same time, since the gradually expanding port 111A reduces the flow velocity of the refrigerant, the residence time of the refrigerant in the outlet 111 area is extended. This makes the vapor-liquid separation process more complete, enabling the gaseous refrigerant to be more thoroughly separated from the liquid refrigerant, reducing the possibility of the liquid refrigerant being entrained into the compressor 4, protecting the normal operation of the compressor 4, and improving the safety and stability of the system.

[0068] During the defrosting of the evaporator, the gradually expanding port 111A helps the melted frost water and condensed water to quickly drain from the outlet 111 to the liquid receiver 2. The gradually expanding shape provides a wider channel for the liquid, reducing the resistance of the liquid flow, enabling the defrosting water to quickly flow from the evaporation coil 1 to the liquid receiver 2. This is like building a smooth slide for the defrosting water, allowing it to quickly slide down, avoiding the accumulation of defrosting water in the evaporation coil 1, thereby improving the defrosting efficiency. It can also effectively prevent the liquid in the liquid receiver 2 from flowing back into the evaporation coil 1 under certain circumstances. Since the diameter of the gradually expanding port 111A gradually increases and faces the upper connection port 21, the liquid tends to flow into the interior of the liquid receiver 2 under the action of gravity rather than flowing back into the evaporation coil 1, ensuring the smooth progress of the defrosting process, maintaining the normal working state of the evaporator, and further improving the performance and reliability of the entire heat pump unit in a low-temperature environment.

[0069] Considering the connection scheme of the lower connection port 22 of the liquid receiver 2, in the evaporator defrosting system provided by the embodiment of the present application, a transition pipe 3 is included. The transition pipe 3 includes a transition inlet 31 and a transition outlet 32. The transition inlet 31 is connected to the lower connection port 22, the transition outlet 32 is arranged towards the body of the evaporator coil 1, and the horizontal position of the transition outlet 32 is lower than the horizontal position of the lower connection port 22.

[0070] In this way, the transition inlet 31 of the transition pipe 3 is connected to the lower connection port 22 of the liquid receiver 2, the transition outlet 32 is arranged towards the body of the evaporator coil 1, and the horizontal position of the transition outlet 32 is lower than that of the lower connection port 22. Such a setting enables the liquid refrigerant separated in the liquid receiver 2 to flow back to the evaporator coil 1 more smoothly under the action of gravity. The evaporation and heat absorption of the liquid refrigerant in the evaporator coil 1 is a key link in the refrigeration or heating cycle of the heat pump unit. The smooth backflow ensures that there is enough liquid refrigerant in the evaporator coil 1 for evaporation, maintaining the stability of the refrigerant cycle, thereby ensuring that the evaporator coil 1 can continuously and efficiently absorb heat from the low-temperature heat source and improving the overall performance of the heat pump unit.

[0071] Since the position of the transition outlet 32 is lower than that of the lower connection port 22, during the operation of the system, it can prevent the liquid refrigerant from directly and rapidly impacting the evaporator coil 1 due to the influence of gravity or other factors, playing a role in buffering and stabilizing the flow of the liquid refrigerant. This helps to prevent the occurrence of liquid hammer phenomenon when the liquid refrigerant enters the evaporator coil 1, protecting the evaporator coil 1 and the pipes and components connected thereto from damage, extending the service life of the equipment, and at the same time reducing the noise and vibration caused by liquid hammer, making the system operate more smoothly and quietly.

[0072] During the defrosting of the evaporator, the melted frost water and condensate will flow downward along the evaporator coil 1. The setting of the transition pipe 3 provides a smooth backflow channel for these liquids, enabling them to flow into the liquid receiver 2. Moreover, since the transition outlet 32 is lower than the lower connection port 22, the liquid is more likely to flow towards the liquid receiver 2 under the action of gravity, avoiding the accumulation of liquid in the evaporator coil 1, accelerating the defrosting speed, improving the defrosting efficiency, ensuring that the evaporator coil 1 can quickly return to the normal heat exchange state after defrosting, and being beneficial to the stable operation of the heat pump unit in a low-temperature environment.

[0073] Considering the specific structural scheme of the transition pipe 3, in the evaporator defrosting system provided by the embodiment of the present application, the transition pipe 3 includes a first U-shaped part 3A and a second U-shaped part 3B. The first U-shaped part 3A is communicated with the second U-shaped part 3B and is symmetrically arranged at the center.

[0074] In this way, when the liquid refrigerant in the liquid storage device 2 flows through the transition pipe 3 to the evaporation coil 1, the first U-shaped part 3A and the second U-shaped part 3B can play a buffering role. The U-shaped structure increases the flow path of the refrigerant, slows down the flow rate of the refrigerant, avoids the rapid impact of the liquid refrigerant on the evaporation coil 1, and ensures a stable flow rate of the refrigerant flowing into the evaporation coil 1. This helps the refrigerant in the evaporation coil 1 to evaporate evenly, enabling the evaporation coil 1 to absorb heat from the outside more efficiently and improving the heating or cooling efficiency of the heat pump unit. The centrally symmetric structure makes the flow of the refrigerant in the transition pipe 3 more uniform. When the refrigerant passes through the two U-shaped parts, it will be adjusted in different directions, reducing the turbulence and eddy currents generated due to sudden changes in the flow direction. This makes the distribution of the refrigerant flowing into the evaporation coil 1 more uniform in each part, facilitating the full play of the heat exchange function of each part of the evaporation coil 1 and improving the overall heat exchange performance of the evaporation coil 1.

[0075] Even if preliminary gas-liquid separation has been carried out in the liquid storage device 2, there may still be a small amount of gaseous components remaining in the refrigerant. The U-shaped structure of the transition pipe 3 will cause the refrigerant to change direction during the flow. Due to its low density, the gaseous refrigerant is more likely to accumulate and float at the turning points of the U-shaped pipe 11, while the liquid refrigerant continues to flow downward. Through multiple turns of the first U-shaped part 3A and the second U-shaped part 3B, further gas-liquid separation can be achieved, reducing the gaseous refrigerant entering the evaporation coil 1 and ensuring that the main component entering the evaporation coil 1 is liquid refrigerant, thereby improving the evaporation efficiency of the evaporation coil 1. At the same time, the entry of gaseous refrigerant into the evaporation coil 1 may occupy a certain space and affect the evaporation effect of the liquid refrigerant. Through further separation by the transition pipe 3, the interference of gaseous refrigerant on the evaporation process of the liquid refrigerant in the evaporation coil 1 can be avoided, enabling the evaporation coil 1 to focus on the evaporation and heat absorption of the liquid refrigerant and enhancing the refrigeration or heating capacity of the heat pump unit.

[0076] During the defrosting of the evaporator, the melted frost water will flow downward along the pipeline. The U-shaped structure of the transition pipe 3 can serve as a temporary water storage area. When the frost water flows to the U-shaped part, it will temporarily stay under the action of gravity. As the frost water accumulates continuously, when it reaches a certain amount, it will continue to flow downward to the liquid storage device 2. This structural design avoids the rapid accumulation of frost water in the evaporation coil 1, ensures that the frost water can be discharged smoothly during the defrosting process, and enables the evaporation coil 1 to quickly return to the normal heat exchange state.

[0077] During the defrosting process, the pressure and temperature in the system will change. The U-shaped structure of the transition pipe 3 can play a certain pressure buffering role, balancing the pressure fluctuations generated during the defrosting process. A stable pressure environment helps the evaporation coil 1 to quickly return to a stable working state after defrosting, ensuring the stability and reliability of the heat pump unit during the defrosting process.

[0078] Considering the scheme of limiting the positions of the two U-shaped parts relative to the outlet 111 area of the evaporation coil 1, in the defrosting system of the evaporator provided by the embodiments of the present application, the top surface of one of the first U-shaped part 3A and the second U-shaped part 3B is flush with the top surface of the U-shaped tube 11.

[0079] In this way, due to the flush top surfaces, according to the principle of communicating vessels, the refrigerant in the U-shaped tube 11 and the U-shaped part flush with it is at the same horizontal height when at rest, and the pressures on both sides are equal. This enables the refrigerant to flow from the U-shaped tube 11 of the evaporation coil 1 into the U-shaped part of the transition tube 3 under a state of pressure balance, avoiding the sudden change in the flow rate of the refrigerant caused by the pressure difference. Thus, the stability of the refrigerant flow rate is ensured, which is beneficial to the uniform evaporation of the refrigerant in the evaporation coil 1 and improves the heat exchange efficiency of the heat pump unit.

[0080] The flush setting provides a clear flow path guidance for the refrigerant. When the refrigerant flows out of the U-shaped tube 11 of the evaporation coil 1, due to the flush top surfaces, it will naturally flow into the U-shaped part of the transition tube 3 that is flush with it, reducing the chaotic flow and resistance at the connection, enabling the refrigerant to enter the transition tube 3 more smoothly, and then flowing towards the body of the evaporation coil 1, which helps to maintain the smoothness of the refrigerant circulation in the whole system.

[0081] When the vapor-liquid mixed refrigerant enters the U-shaped tube 11 and the U-shaped part flush with it, according to the principle of communicating vessels, the liquid refrigerant will sink to the bottom under the action of gravity, and the gaseous refrigerant will gather at the top. Due to the flush top surfaces, the U-shaped tube 11 and the U-shaped part form a relatively large and stable vapor-liquid separation space, extending the path and time of vapor-liquid separation, enabling the gaseous refrigerant and the liquid refrigerant to be more fully separated, improving the purity of the liquid refrigerant entering the evaporation coil 1, and further enhancing the evaporation efficiency of the evaporation coil 1. At the same time, the flush setting ensures the stability of the pressure and liquid level in the U-shaped tube 11 and the U-shaped part, making the vapor-liquid separation process not affected by external factors. During the operation of the heat pump unit, even if the system pressure and temperature change, due to the balancing effect of the communicating vessels, the vapor-liquid separation state in the U-shaped tube 11 and the U-shaped part can remain relatively stable, providing a stable liquid refrigerant supply for the evaporation coil 1, which helps to improve the overall performance and stability of the heat pump unit.

[0082] During the defrosting process, the melted frost water flows from the evaporator coil 1 to the U-shaped pipe 11. When the frost water flows to the U-shaped pipe 11 and the U-shaped part flush with it, according to the principle of communicating vessels, the frost water will be evenly distributed between the two. Due to the existence of the U-shaped part, the storage space for the frost water is increased, and the flush top surface enables the frost water to flow more smoothly between the two, avoiding the accumulation of frost water in the U-shaped pipe 11, quickly discharging the frost water to the liquid receiver 2, accelerating the defrosting speed, and enabling the evaporator coil 1 to return to the normal heat exchange state faster. At the same time, the communicating vessel structure formed by the flush setting makes the frost water in the U-shaped pipe 11 and the U-shaped part maintain the same liquid level when static, preventing the frost water from flowing back to the evaporator coil 1 due to system pressure fluctuations or other factors. This helps to keep the evaporator coil 1 dry, reduces corrosion and icing problems caused by frost water residue, extends the service life of the evaporator coil 1, and is also beneficial to improving the operating efficiency of the heat pump unit after defrosting.

[0083] In addition, in the evaporator defrosting system provided by the embodiment of the present application, the liquid receiver 2 may further include an inlet pipe, an outlet pipe, and a filter assembly. Exemplarily, the material of the inlet pipe is red copper (TP2Y), which is connected to the red copper pipe at the air conditioner evaporator end and bears a relatively high pressure. The material of the outlet pipe is red copper (TP2Y\TP2M), which is connected to the red copper pipe at the suction end of the compressor 4 cylinder and bears a relatively low pressure. An "oil return hole" is processed on the outlet pipe at the bottom of the cylinder body. The filter assembly generally has a mesh cloth and a mesh frame. The mesh cloth is made of stainless steel material, and the mesh frame is made of SPCC deep-drawing steel plate for filtering to prevent some insoluble components inside the air conditioning system from flowing into the compressor 4 and damaging the compressor 4.

[0084] The structure of the transition pipe 3 is different in different refrigeration systems. For example, in the refrigeration system of some refrigerators, the transition pipe 3 includes a straight pipe section and a gradually expanding section. The straight pipe section is connected to the capillary tube, and the diameter of the gradually expanding section gradually increases, forming a conical tube structure for realizing refrigerant rectification and reducing the generation of eddy currents. In the refrigeration systems of some other refrigerators, there is also a transition pipe 3 made of copper tube stretching, which is connected between the capillary tube and the evaporator and is widely used as a noise reduction accessory.

[0085] It should be noted that there is a close relationship between the liquid receiver 2, the transition pipe 3 and the evaporator coil 1 of the evaporator:

[0086] The liquid receiver 2 is installed at the evaporator of the air conditioner and the suction pipe part of the compressor 4. The refrigerant gas-liquid mixture coming out of the evaporator evaporation coil 1 enters the liquid receiver 2, where gas-liquid separation occurs. Since the liquid refrigerant is heavier than the gas itself, it will directly fall to the bottom of the liquid receiver 2 cylinder, and the vaporized refrigerant enters the compressor 4 from the outlet 111 of the liquid receiver 2, thus preventing the compressor 4 from sucking in liquid refrigerant and causing liquid hammer. At the same time, the liquid receiver 2 can also store a certain amount of refrigerant, playing a buffering and regulating role in the refrigerant flow in the system, ensuring a stable refrigerant supply to the evaporator and maintaining the stability of the evaporation pressure.

[0087] The transition pipe 3 is connected between the capillary outlet 111 of the evaporator and the evaporation coil 1, and its function is to smoothly introduce the refrigerant after throttling and pressure reduction by the capillary into the evaporation coil 1. For example, the transition pipe 3 that plays a noise reduction role can make the internal pressure change smoothly, avoiding the drastic pressure change at the tail of the traditional capillary, preventing the generation of noise caused by jetting or flashing, and enabling the refrigerant to evaporate and absorb heat more stably in the evaporation coil 1, thereby improving the refrigeration efficiency.

[0088] In the heat pump system, the refrigerant enters the evaporation coil 1 in the form of a low-temperature and low-pressure liquid. When it flows through the evaporation coil 1, it absorbs the heat of the surrounding environment (such as absorbing the heat of outdoor air in an air-source heat pump) and starts to evaporate and vaporize. During this process, the refrigerant gradually changes from a liquid state to a gaseous state, but in the entire evaporation coil 1, not all the refrigerant can instantly and completely vaporize into a gaseous state. Instead, there is a part of the liquid refrigerant that is absorbing heat and evaporating, and another part that has already vaporized into a gaseous state. Therefore, the refrigerant in the evaporation coil 1 is in a state of coexistence of gas and liquid. Only when the refrigerant completely passes through the evaporation coil 1 and absorbs enough heat will it be completely converted into a gaseous state and then enter the compressor 4 for compression.

[0089] It should be noted that in the evaporator defrosting system, the compressor 4, condenser 5, dryer 6, evaporator, liquid receiver 2, and capillary (return air heat exchange section) 7 are connected in sequence through pipelines to form a closed circulation system. When the refrigeration function is running, the compressor 4 compresses the low-temperature and low-pressure gaseous refrigerant into a high-temperature and high-pressure gaseous state, discharges it into the condenser 5 to be cooled and condensed into a liquid state, enters the liquid receiver 2 after being dried and filtered by the dryer 6, and then passes through the capillary 7 to be throttled and depressurized into a low-temperature and low-pressure liquid state and enters the evaporator, where it absorbs heat and evaporates into a low-temperature and low-pressure gaseous state, and finally is sucked into the compressor 4, so as to cycle and achieve refrigeration.

[0090] Specifically, the compressor 4 plays a core power role. It compresses the low-temperature and low-pressure gaseous refrigerant into a high-temperature and high-pressure gaseous refrigerant, providing power for the circulation of the refrigerant in the system. The condenser 5 cools and condenses the high-temperature and high-pressure gaseous refrigerant into a liquid refrigerant, releasing heat during this process and changing the state of the refrigerant. The dryer 6 is used to remove moisture and impurities in the refrigerant, preventing problems such as ice blockage and corrosion in the system and ensuring the normal operation of the system. The capillary tube (suction heat exchange section) 7 throttles and reduces the pressure of the liquid refrigerant through its small pipe diameter characteristic, enabling the refrigerant to quickly evaporate and absorb heat in the evaporator. At the same time, the suction heat exchange section can also conduct heat exchange with the suction gas, improving the refrigeration efficiency and performance of the system.

[0091] Regarding the application of the compressor 4 during the defrosting process, by starting the compressor 4, the liquid bubbles with liquid formed at the pipe orifice of the evaporator coil 1 can be pumped out. In this way, the problem of the "gurgling" sound can be solved at the root.

[0092] The embodiment of the present application also provides a defrosting control method, including:

[0093] Controlling the heater to start with a first power to heat the evaporator coil 1 so that liquid refrigerant generates liquid bubbles with liquid inside the pipe orifice of the evaporator coil 1;

[0094] Determining that the heater starts and meets a first preset time, and controlling the heater to stop heating;

[0095] Controlling the compressor 4 to start at a preset frequency to pump out the liquid bubbles with liquid accumulated at the pipe orifice of the evaporator coil 1, and the preset frequency is less than the first power;

[0096] Determining that the compressor 4 starts and meets a second preset time, and controlling the compressor 4 to stop running;

[0097] Repeating the above process until the liquid refrigerant meets the preset conditions.

[0098] In the solution of the defrosting control method, the execution entity is the controller. First, the controller starts with a first power to heat the evaporator coil 1, causing the liquid refrigerant to generate liquid bubbles with liquid inside the pipe orifice of the evaporator coil 1. High-power heating can quickly increase the temperature of the evaporator coil 1, break the thermal balance between the frost layer on the coil surface and the refrigerant, accelerate the melting of the frost layer, and prompt the liquid refrigerant to form liquid bubbles with liquid, thereby efficiently performing the defrosting process. Second, after determining that the heater starts and meets the first preset time, control the heater to stop heating to avoid unnecessary power consumption caused by continuous heating. Then control the compressor 4 to start at a preset frequency. By this intermittent, phased, and reasonably set power method, while realizing the defrosting function, the overall energy consumption is reduced.

[0099] Exemplarily, the preset frequency can be understood as low-frequency startup, which reduces the energy consumption of the compressor 4 while ensuring that the liquid-carrying bubbles accumulated at the nozzle of the evaporation coil 1 can be pumped out. Or, in some specific scenario requirements, the preset frequency can also be understood as high-frequency startup.

[0100] Considering the cut-off condition solution for pumping out small bubbles, in the defrost control method provided by the embodiments of the present application, in the step of "repeating the above process until the liquid refrigerant meets the preset conditions", the preset conditions include at least one of the following:

[0101] The sum of multiple first preset times of multiple heater startups is equal to the first preset time value; or

[0102] It is determined that the liquid refrigerant in the evaporation coil 1 is completely vaporized; or

[0103] It is determined that the liquid-carrying amount of the bubbles in the evaporation coil 1 is lower than the preset amount value; or

[0104] It is determined that the generation rate of the liquid-carrying bubbles meets the preset rate range.

[0105] In this way, when the sum of multiple first preset times of multiple heater startups is equal to the first preset time value, it is used as the cut-off condition. This method macroscopically controls the defrosting process by accumulating the heating time. In practical applications, reasonable first preset time values can be preset according to parameters such as the refrigeration capacity of the refrigerator and the evaporator specifications. For example, for a small refrigerator with a small evaporator area and relatively short defrosting time required, a shorter first preset time value is set. When the accumulated heating time reaches this value, it is considered that the defrosting is basically completed, and the defrosting operation can be stopped to avoid over-defrosting and achieve precise control of the defrosting process.

[0106] Or, determining that the liquid refrigerant in the evaporation coil 1 is completely vaporized as the cut-off condition can judge whether the defrosting is complete from the actual state of the refrigerant. The complete vaporization of the liquid refrigerant means that the frost layer on the surface of the evaporation coil 1 has completely melted and turned into gas, and the defrosting process reaches an ideal state. By monitoring the state changes of the refrigerant through devices such as temperature sensors and pressure sensors, once it is detected that the liquid refrigerant is completely vaporized, the defrosting operation is immediately stopped to ensure the defrosting effect and avoid energy waste at the same time.

[0107] Or, taking the liquid-carrying amount of the bubbles in the evaporation coil 1 being lower than the preset amount value as the cut-off condition can quantify the defrosting degree. The amount of liquid-carrying bubbles directly reflects the remaining situation of the liquid refrigerant after the frost layer melts. When the liquid-carrying amount is lower than the preset amount value, it indicates that the defrosting is approaching the end, and the remaining liquid refrigerant is less, which will not have a great impact on the subsequent operation of the refrigeration system. By setting a reasonable preset amount value, unnecessary defrosting time and energy consumption can be reduced while ensuring the defrosting effect.

[0108] Alternatively, determining that the generation rate of liquid-carrying bubbles meets a preset rate range is used as a cut-off condition to judge the defrosting process from a dynamic change perspective. In the initial stage of defrosting, there is more frost layer and the generation rate of liquid-carrying bubbles is faster; as the defrosting progresses, the frost layer gradually decreases and the bubble generation rate will also gradually decrease. When the generation rate enters the preset rate range, it indicates that the defrosting has entered the later stage and the residual frost layer is less. At this time, stopping the defrosting operation can not only ensure the defrosting effect but also improve the defrosting efficiency.

[0109] In summary, different cut-off conditions avoid energy waste during the defrosting process from multiple perspectives. The control based on the time sum prevents power consumption caused by overheating; the control based on the refrigerant vaporization state, the liquid content in the bubbles, and the bubble generation rate ensures that the heater and the compressor 4 are stopped in time when the defrosting is completed, avoiding unnecessary continuous operation of the equipment, thus effectively improving the energy utilization efficiency. Further, these cut-off conditions ensure that the defrosting process ends at an appropriate node, avoiding the decrease in refrigeration efficiency caused by insufficient defrosting and the damage to the components of the refrigeration system caused by excessive defrosting. For example, if the defrosting is insufficient, the remaining frost layer will affect the heat exchange efficiency of the evaporator; if the defrosting is excessive, the temperature of the evaporator may be too high, affecting the subsequent refrigeration effect and even having an adverse impact on components such as the compressor 4. Through reasonable cut-off conditions, the stable operation of the refrigeration system is guaranteed.

[0110] Exemplarily, the first power and the preset frequency may not be fixed, but instead, the power of the heater and the compressor 4 may be dynamically adjusted according to the data fed back by sensors such as the temperature of the evaporation coil 1 and the temperature inside the refrigerator. For example, in the initial stage of defrosting, according to the frost layer thickness and temperature, the power of the heater is increased to defrost quickly; as the defrosting progresses, the power of the heater is gradually decreased. For the compressor 4, according to the accumulation speed of the liquid-carrying bubbles and the pressure change, its operating frequency is adjusted in real time to achieve more refined energy-saving control.

[0111] Exemplarily, a variable-frequency heater and a variable-frequency compressor 4 may also be used, and the heating power of the heater and the operating frequency of the compressor 4 are continuously adjusted through variable-frequency technology. During the defrosting process, according to the system operating state, the heater and the compressor 4 work together at different powers and frequencies, which can not only ensure the defrosting effect but also further optimize the energy consumption and reduce the mechanical wear caused by the start and stop of the equipment.

[0112] Exemplarily, an ambient temperature sensor may also be added to adjust the defrosting control strategy according to the ambient temperature. When the ambient temperature is low, the starting power and the operating time of the heater are appropriately reduced, and at the same time, the working parameters of the compressor 4 are adjusted; when the ambient temperature is high, the working intensity of the heater and the compressor 4 is correspondingly increased to meet the defrosting requirements under different environmental conditions and achieve more efficient defrosting and energy saving.

[0113] Considering the scenario of starting the heater or compressor 4 at a constant interval, in the defrost control method provided by the embodiments of the present application, the first power, the first preset time, the preset frequency, and the second preset time all adopt constant values.

[0114] In this way, since the first power, the first preset time, the preset frequency, and the second preset time all adopt constant values, the defrost control program does not require complex dynamic calculations and real-time adjustments. In practical applications, the controller only needs to start and stop the heater and compressor 4 in sequence according to the preset fixed parameters. For example, each time the heater is started, it runs at a fixed first power for the first preset time, and then the compressor 4 runs at a fixed preset frequency for the second preset time. This constant control mode greatly simplifies the design and programming of the control system, reduces the complexity of the control logic, reduces program errors or control chaos that may occur due to dynamic parameter adjustment, and improves the reliability of defrost control.

[0115] Furthermore, the constant parameter setting makes the defrost process repetitive and predictable. In the same working environment, the heating power, heating time, operating power and time of the compressor 4 during each defrost are kept consistent, thus ensuring the stability of the defrost effect. For example, for a specific model of refrigerator, whenever the defrost program is started, as long as the working environment temperature, humidity and other conditions are similar, the constant parameter setting can make the frost layer on the evaporator melt at a similar speed, and the liquid refrigerant is processed in a fixed manner, avoiding the situation of incomplete defrost or over-defrost caused by parameter fluctuations, and maintaining the stable working performance of the refrigeration system.

[0116] Considering the scheme of the change in the start time of the heater during the defrost process, in the defrost control method provided by the embodiments of the present application, during multiple start processes, the first preset time gradually decreases; or, when the bubble generation rate increases, the first preset time gradually increases.

[0117] In this way, at the initial stage of defrosting, the frost layer on the evaporator surface is relatively thick, and a large amount of heat input is required to quickly melt the frost layer. At this time, starting the heater with the first preset time for a longer period and the first power can provide sufficient heat, accelerate the melting speed of the frost layer, quickly generate liquid-carrying bubbles, and improve the efficiency at the initial stage of defrosting. As the defrosting progresses, the frost layer gradually decreases, and the heat required for the remaining frost layer and liquid refrigerant on the evaporator surface also decreases accordingly. The gradual decrease of the first preset time means that the operating time of the heater is shortened when starting later, avoiding overheating, and thus saving energy consumption during the subsequent defrosting process; during the process, if it is found that the bubble generation rate increases, the restart time of the heater increases again, which can prevent more liquid-carrying bubbles from being generated in the evaporation coil 1. For example, when the heater is started for the first time, the first preset time is set to 5 minutes. As the defrosting progresses, the subsequent startup time is successively reduced to 4 minutes, 3 minutes, etc., reducing energy consumption while ensuring the defrosting effect. If the bubble generation rate increases, the heater is restarted for 3 minutes, 4 minutes, 5 minutes, etc. to extract the newly generated liquid-carrying bubbles.

[0118] Furthermore, due to the gradual decrease of the first preset time, the defrosting process shows a trend of dynamic optimization. Concentrating heat in the early stage of defrosting to quickly process a large amount of frost layer, and reducing the heating time according to the actual situation in the later stage, making the entire defrosting process more compact and reasonable. Compared with the scheme with a constant first preset time, this scheme can avoid the time waste caused by too long heating time in the later stage of defrosting, thus effectively reducing the overall defrosting time. For example, for an evaporator with the same amount of frost formation, defrosting with a constant time may take 30 minutes, while using the scheme with the gradually decreasing first preset time, it may be possible to complete defrosting in 25 minutes, improving the usage efficiency of the refrigerator.

[0119] In addition, during the defrosting process, the heating of the heater will increase the temperature of the evaporator and its surrounding areas, causing a certain thermal shock to the refrigeration system. In the later stage of defrosting, as the first preset time gradually decreases, the operating time of the heater is shortened, the generated heat is reduced, and the rising amplitude of the evaporator temperature is reduced, thus reducing the thermal shock to the refrigeration system. This helps to protect the components of the refrigeration system, extend its service life, and at the same time enables the refrigerator to return to the normal refrigeration state faster after defrosting and maintain the stability of the internal temperature.

[0120] Considering another feasible scheme of the defrosting control method, in the defrosting control method provided by the embodiments of the present application, before the step of controlling the heater to start with the first power to heat the evaporation coil 1 so that the liquid refrigerant generates liquid-carrying bubbles at the pipe orifice of the evaporation coil 1, the method includes: determining that the refrigeration device is in the defrosting cycle and controlling the compressor 4 to stop running.

[0121] In this way, the defrosting is started only after the defrosting cycle is accurately determined, thus avoiding unnecessary defrosting energy consumption. Moreover, after the compressor 4 stops running, the electric energy required for the operation of the compressor 4 does not need to be consumed during the defrosting process, thereby reducing the energy consumption of the entire defrosting process. In addition, the efficient defrosting process reduces the problem of decreased refrigeration efficiency caused by incomplete defrosting, indirectly saves the energy consumed in the refrigeration process, and realizes the optimal utilization of energy.

[0122] Considering the scheme of variable power heating of the heater, in the defrost control method provided in the embodiment of the present application, after determining that the refrigeration equipment is in a defrost cycle and controlling the compressor 4 to stop running, the method includes: controlling the heater to start at a second power to heat the evaporating coil 1.

[0123] In this solution, the second power can be a constant power or a variable frequency power.

[0124] In this way, in the initial stage of defrosting, the heater starts with a relatively low power, avoiding the impact of high-power instantaneous start-up on circuits and equipment during traditional defrosting. Just as a slow start of a car can reduce the wear of parts, a relatively low starting power can reduce the load pressure of the heater itself and the electrical components of the entire refrigeration system, reduce the risk of failure caused by sudden current changes, and extend the service life of the equipment. As the power gradually increases, the system can smoothly adapt to the heating process, and will not produce drastic temperature fluctuations and pressure changes due to sudden power changes, ensuring the stability of the defrosting process.

[0125] At the beginning of defrosting, the frost layer on the evaporator surface is thicker. At this time, a smaller heating power can preheat the frost layer first, so that the frost layer starts to melt slowly from the surface, avoiding the situation where the frost surface vaporizes rapidly due to a sudden temperature rise, while the inside is still not melted. As the frost layer gradually melts, the heater power gradually increases, which can provide more heat to accelerate the melting of the remaining frost layer and the vaporization of the liquid refrigerant, so that the defrosting process matches the progress of the frost layer melting. For example, when the frost layer is thick, slowly heat it at low power for 1-2 minutes, and then gradually increase the power after the frost layer is initially softened. Compared with heating at high power from the beginning, this method can complete the defrosting more efficiently and shorten the defrosting time.

[0126] Since the heater power is gradually increased according to the defrosting process, energy waste caused by using too high power in the early stage of defrosting is avoided. When defrosting does not require a lot of heat, low-power operation reduces power consumption; as the demand for defrosting increases, the power is increased accordingly, achieving on-demand heating. Compared with fixed high-power defrosting, this variable power heating method can effectively reduce energy consumption during the defrosting process while ensuring the defrosting effect, thereby improving energy utilization efficiency.

[0127] Considering the power scheme of the heater in the heater frequency conversion scheme, in the defrost control method provided in the embodiment of the present application, the starting power of the second power is greater than the first power.

[0128] In this way, whether the second power is a constant power or a variable-frequency power, the starting power of the second power is greater than the first power, which means that in the initial stage of defrosting, the heater can provide a more powerful heat output. When the refrigeration device enters the defrosting cycle and the compressor 4 stops running, the higher starting power can quickly raise the temperature of the evaporator coil 1, accelerate the melting speed of the frost layer, and more quickly generate liquid-carrying bubbles inside the pipe orifice of the evaporator coil 1. For example, when starting heating with the first power conventionally, it may take several minutes for the frost layer to start melting significantly and generate liquid-carrying bubbles. However, with the second power having a larger starting power, this state can be achieved in a shorter time. Subsequently, as the power gradually increases, the defrosting process continues to accelerate, effectively shortening the overall defrosting time, enabling the refrigerator to return to the normal refrigeration state faster, and improving the usage efficiency.

[0129] Specifically, in some cases, such as when the refrigerator has not been defrosted for a long time or the environmental humidity is relatively high, the frost on the evaporator surface will be thicker and harder. At this time, the larger starting power can better cope with this complex frosting condition. It can break through the heat insulation obstacle of the thick frost layer, deeply heat the evaporator, ensure that the frost layer starts to melt from the inside, and avoid the situation where the surface melts while there is still a large amount of frost remaining inside. The continuously increasing power can also ensure that in the later stage of defrosting, even when the frost layer gradually decreases, there is enough heat to completely vaporize the remaining frost and liquid refrigerant, ensuring thorough defrosting, maintaining good heat exchange performance of the evaporator, and guaranteeing the refrigeration effect of the refrigerator.

[0130] Considering the process of power adjustment according to bubbles, in the defrosting control method provided by the embodiments of the present application, during multiple startup processes, the change in the first power at which the heater starts is positively correlated with the bubble generation rate.

[0131] In this way, the bubble generation rate can intuitively reflect the melting process of the frost layer on the evaporator coil. When the frost layer is thick, more liquid refrigerant is generated by melting, and the bubble generation rate is fast. At this time, the heater automatically increases the first power to provide more heat to accelerate the melting of the frost layer. As the defrosting progresses, the frost layer gradually thins, the bubble generation rate decreases, and the first power of the heater also decreases accordingly to avoid overheating. For example, in the initial stage of defrosting, if the bubble generation rate reaches 10 per minute, the heater operates at a relatively high power of 800 W. As the defrosting proceeds, when the bubble generation rate drops to 3 per minute, the power is automatically adjusted down to 400 W. This dynamic adjustment method enables the heater power to always match the actual defrosting requirements, greatly improving the defrosting efficiency and shortening the defrosting time. When the bubble generation rate continues to increase to 10 per minute, the heater continues to operate at a relatively high power of 800 W, or a higher power model can also be selected.

[0132] Considering the solution after the controller controls the compressor 4 to almost completely extract the liquid-containing bubbles during the defrosting process, in the defrosting control method provided by the embodiments of the present application, after repeating the above process until the liquid refrigerant meets the preset conditions, the method includes: controlling the heater to start with a third power to heat the evaporation coil 1, and the third power meets the trend of gradually increasing power.

[0133] In this way, when the compressor 4 almost completely extracts the liquid-containing bubbles, there may still be a small amount of frost or liquid refrigerant remaining on the surface and inside of the evaporation coil 1. At this time, controlling the heater to start with a third power and the power gradually increasing can accurately perform secondary heating on the evaporation coil 1. The initially small power can gently handle the remaining frost and liquid refrigerant, avoiding local temperature sudden rise caused by excessive power, resulting in excessive gasification of the refrigerant or generating thermal stress on the evaporation coil 1. As the power gradually increases and the heat continuously increases, these remaining substances can be completely melted and gasified, ensuring the surface of the evaporation coil 1 is clean, restoring its efficient heat exchange performance, avoiding affecting the subsequent refrigeration effect due to the remaining substances, and ensuring the stable operation of the refrigerator.

[0134] Considering the operation scheme of the heater after the controller controls the compressor 4 to almost completely extract the liquid-containing bubbles during the defrosting process, in the defrosting control method provided by the embodiments of the present application, the starting power of the third power is greater than the first power.

[0135] In this way, when the compressor 4 almost completely extracts the liquid-containing bubbles, the remaining frost layer and liquid refrigerant on the evaporation coil 1 are difficult to handle because they adhere tightly and are unevenly distributed. The starting power of the third power being greater than the first power enables the heater to release strong heat at the beginning. Under the rapid impact of the heat, the remaining frost layer rapidly heats up and cracks, and the liquid refrigerant also accelerates gasification. For example, in the defrosting scenario of an ordinary household refrigerator, if it takes 5 minutes to handle the remaining substances with the first power heating, the third power with a high starting power may be able to complete it within 3 minutes, greatly improving the thoroughness and efficiency of defrosting and ensuring the subsequent efficient heat exchange of the evaporator.

[0136] Considering the solution to control the stop of the defrosting process, in the defrosting control method provided by the embodiments of the present application, after repeating the above process until the liquid refrigerant meets the preset conditions, the method includes: determining that the refrigeration device meets the condition to exit defrosting, controlling the heater to stop, and controlling the compressor 4 to enter the refrigeration cycle.

[0137] In this way, after repeating the defrosting operation until the liquid refrigerant meets the preset conditions, it is further determined that the refrigeration device meets the defrosting exit conditions, which provides a double guarantee for the defrosting effect. The preset conditions may only judge the defrosting progress from the state of the liquid refrigerant, while the defrosting exit conditions comprehensively consider the operating state of the entire refrigeration device, such as the evaporator temperature, system pressure, etc. When all these conditions are met, the heater is controlled to stop, ensuring that the frost layer on the evaporator surface is completely melted and the liquid refrigerant is fully vaporized, avoiding the influence on the heat exchange efficiency of the evaporator due to incomplete defrosting, and thus maintaining the good refrigeration performance of the refrigerator. For example, if the defrosting is stopped only based on the state of the liquid refrigerant, there may be a small amount of residual frost in the corners of the evaporator, while by comprehensively judging the defrosting exit conditions, such problems can be eliminated.

[0138] Specifically, after clarifying the defrosting exit conditions, the heater is controlled to stop and the compressor 4 enters the refrigeration cycle in sequence, enabling a smooth switch in the operating state of the refrigeration device. After the heater stops, the system temperature gradually stabilizes. At this time, the compressor 4 is started to enter the refrigeration cycle, avoiding the current impact and mechanical wear that may be caused by starting the compressor 4 when the system temperature is unstable. At the same time, this orderly control method allows parameters such as the refrigerant pressure and temperature in the system to transition naturally, reducing the adverse effects on the refrigeration system due to sudden changes in the device state and extending the service life of the device.

[0139] Considering the specific scheme of the defrosting exit conditions, in the defrosting control method provided in the embodiments of the present application, the defrosting exit conditions include: the total duration of continuous startup of the heater is greater than or equal to a second preset time value, and the second preset time value is greater than the first preset time value.

[0140] In this way, since the second preset time value is greater than the first preset time value, and the total duration of continuous startup of the heater being greater than or equal to the second preset time value is used as the defrosting exit condition, it can ensure that there is sufficient duration for the defrosting process. During the defrosting process, the first preset time corresponds to the duration of each stage of defrosting when the heater is started, but single or several defrostings may not be able to completely melt all the frost layers. When the total duration of continuous startup of the heater reaches or exceeds the second preset time value, it ensures that there is enough time to completely heat and melt the frost layer on the evaporator surface and the remaining liquid refrigerant from the time dimension. For example, in a common household refrigerator, if the first preset time is 5 minutes to deal with general frosting, and the second preset time is set to 20 minutes, when the refrigerator has thick frosting, after multiple defrosting operations, the cumulative heating duration reaches 20 minutes, which can basically ensure that the defrosting is completed thoroughly, avoiding a decrease in refrigeration efficiency due to insufficient defrosting time.

[0141] In addition, using the total sum of the continuous startup time of the heater as the defrost exit condition results in a simple and straightforward control logic. The controller only needs to accumulate the startup time of the heater each time. When the preset second preset time value is reached, the defrost exit operation can be triggered. Compared with judging the defrost exit condition by integrating multiple complex parameters (such as temperature, pressure, bubble state, etc.), this time control method does not require complex sensor data acquisition and analysis processing, reducing the complexity of the control system and the probability of errors. In actual production and application, it is easier to implement and maintain, enhancing the reliability of the defrost control scheme.

[0142] Exemplarily, the evaporator defrost system and defrost control method according to the embodiments of the present application can operate as follows.

[0143] Exemplarily, the refrigeration device is a refrigerator. When the refrigerator is powered on and refrigerating, generally, when the freezer reaches -18°C, the compressor 4 stops. During the subsequent process, cold leakage will occur in the refrigerator. To avoid continuous cold leakage and control the temperature of the refrigerator to rise, the compressor 4 is restarted later, and the continuous startup is usually 24 hours. In this way, a certain amount of frost accumulates on the refrigerator evaporation coil 1.

[0144] During the traditional defrost process, when the heater is turned on for 3 - 5 minutes, the heat conduction of the liquid refrigerant in the coil does not reach the evaporator. When it continuously starts for 5 - 15 minutes, gurgling sounds will be generated. After starting for 15 minutes, the liquid refrigerant is completely vaporized, and gas is ejected from the pipe orifice, so there will be no gurgling sounds.

[0145] In this way, the defrost function of the embodiments of the present application is actually applied between 5 - 15 minutes of continuous startup of the refrigerator. The total heating time of the heater in the defrost control method of this solution can be set to 15 minutes.

[0146] During the defrost process of the compressor 4, the startup time each time can be 30 seconds. Almost all the liquid bubbles can be pumped out for the first time or the first two or three times. During the subsequent startup process of the compressor 4, the liquid refrigerant is almost completely vaporized. Perhaps there will be no liquid bubbles at the orifice of the evaporation coil 1, but normal vaporized gaseous refrigerant.

[0147] The interval time of the compressor 4 is from short to long. It can also be understood that the startup time of the heater is from short to long according to the number of times. It should be noted that during the stage when the liquid refrigerant in the evaporation coil 1 is just vaporized, the gas generation rate is getting faster and faster, and there is more liquid carried. Most of it is gaseous later, and the liquid becomes less until it stops.

[0148] Moreover, within the 30 - second startup time of the compressor 4, it does not affect the temperature of the evaporation coil 1 from continuing to rise. And during the process, the bubble generation rate of the liquid refrigerant in the evaporation coil 1 is not affected.

[0149] Exemplarily, the heater can be started successively for 5 minutes, 3 minutes, 3 minutes... according to the sequence of the number of intervals until the overall heating time of the heater meets 15 minutes.

[0150] Based on this, by applying the evaporator defrosting system and defrosting control method provided in the embodiments of the present application, the evaporator is changed to be connected to the connection port 21 on the liquid receiver 2 through the evaporation coil 1, and the transition pipe 3 extends into the lower connection port 22 of the liquid receiver 2. Since there is a U-shaped pipe 11 in the outlet 111 area of the evaporation coil 1, part of the gaseous refrigerant can be accumulated, reducing the frequency of abnormal noise. At the same time, the connection between the outlet 111 area of the evaporation coil 1 and the connection port 21 on the liquid receiver 2 is a gradually expanding port 111A, which can reduce the sound of bubble rupture. In addition, even if there is too much residual liquid refrigerant in the liquid receiver 2, it will not liquid seal the outlet 111 of the evaporation coil 1, further reducing the possibility of abnormal noise generation.

[0151] Based on the above structural characteristics, when the compressor 4 starts, a pressure difference is established at the inlet and outlet 111 of the evaporation coil 1, and the generated small-bubble gaseous refrigerant is timely pumped back to prevent the gaseous refrigerant from accumulating and growing during the upward movement. At the same time, when the compressor 4 starts, the outlet 111 of the evaporation coil 1 is in a low-pressure area, which can further evaporate the liquid refrigerant in the liquid receiver 2, avoiding the possibility of the liquid refrigerant liquid-sealing the outlet 111 of the evaporation coil 1.

[0152] The specific control method is as follows:

[0153] S10: When the defrosting condition is met, the device enters the defrosting cycle. At this time, the heater works and times, and the compressor 4 stops;

[0154] Specifically, in this step, the refrigeration device is powered on and operates. After the compressor 4 operates for a period of time and meets the defrosting condition, the refrigeration device enters the defrosting cycle. At this time, the heater works and times the working duration, the compressor 4 maintains the stopped state, and the frost layer on the bottom surface of the evaporator melts first, and the liquid refrigerant at the bottom of the pipe gradually evaporates.

[0155] S11: Every interval of time △T, the compressor 4 starts and runs at a low speed for a time t and then stops;

[0156] Specifically, the heater operates for △T, preferably for 3 minutes. At this time, a large number of gaseous bubbles are generated in the evaporator and adhere to the inner wall of the pipe and the U-shaped pipe 11 at the inlet section of the liquid reservoir 2. After the compressor 4 starts at a low speed and maintains for a time t, preferably for 30 seconds, the compressor 4 stops running. Due to the start of the compressor 4, a large amount of gaseous refrigerant is pumped back into the compressor 4, and at the same time, part of the liquid refrigerant in the liquid reservoir 2 evaporates. When the working duration of the heater reaches 2△T, the compressor 4 starts again, and so on. Further, according to the gasification law of the refrigerant in the evaporator, in the initial stage, the bubble generation speed is slow, then it speeds up, and finally it slows down again until complete gasification. Therefore, the starting timing of the compressor 4 can be dynamically adjusted. For example, the first start is at △T, the second start interval is 1 / 2△T, the third start interval is 1 / 2△T, and the fourth until the last interval is △T.

[0157] S12: Until the working time of the heater exceeds the time T, the compressor 4 maintains the shutdown state;

[0158] Specifically, as the liquid refrigerant in the evaporator gasifies, the liquid-carrying amount of the gaseous refrigerant at the outlet 111 of the evaporation coil 1 decreases, and the abnormal sound gradually decreases until it disappears. Therefore, when the working duration of the heater exceeds T, preferably, T is taken as 10 minutes, there is no need to promptly pump the gaseous refrigerant back into the compressor 4, and the compressor 4 maintains the shutdown state. At this time, only the heater operates.

[0159] S13: When the device meets the defrost exit condition, the device re-enters the refrigeration cycle.

[0160] Specifically, when the heater continues to operate and meets the defrost exit condition, such as the working duration of the heater or the temperature at the outlet 111 of the evaporator meets the set requirements, the heater stops working and exits the defrost cycle, and the device operates normally for refrigeration.

[0161] Further, through the above analysis, the law of the generation of liquid-carrying bubbles in the evaporator can be jointly controlled with a variable-power heater. For example, in the starting stage, the power of the heater increases to quickly enter the bubble generation stage, then the power of the heater is reduced to cooperate with the start of the compressor 4 to pump back the gaseous refrigerant. When the liquid refrigerant is completely gasified, the power of the heater is increased again for rapid defrosting to shorten the working time of the heater and reduce the rise of the storage temperature in the device.

[0162] It should be understood that the terms used herein are for the purpose of describing particular example embodiments only and are not intended to be limiting. Unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" as used herein may also include the plural forms. The terms "comprising", "including", "containing", and "having" are inclusive and thus specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the particular order described or illustrated, unless explicitly indicated as the order of performance. It should also be understood that additional or alternative steps may be used.

[0163] Although the terms first, second, third, etc. may be used herein to describe multiple elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another. Unless the context clearly indicates otherwise, terms such as "first", "second", and other numerical terms when used herein do not imply an order or sequence. Thus, the first element, component, region, layer, or section discussed below may be referred to as a second element, component, region, layer, or section without departing from the teachings of the example embodiments.

[0164] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. An evaporator defrosting system, characterized in that: In a refrigeration device with a compressor, the system comprises: Evaporation coil; A liquid reservoir (2), the liquid reservoir (2) comprising an upper connecting port (21) and a lower connecting port (22); The outlet (111) of the evaporating coil (1) is configured to be connected to the upper connection port (21) from above the liquid storage container (2); A compressor connected to the inlet of the evaporating coil (1) and used to provide power for the refrigerant circulation; A heater, the heater being arranged around or below the body of the evaporating coil (1); A controller is used to control the heater to heat the evaporating coil (1) so that the liquid refrigerant generates liquid bubbles in the pipe mouth of the evaporating coil (1); and to control the compressor to extract the liquid bubbles accumulated at the pipe mouth of the evaporating coil (1).

2. The evaporator defrosting system according to claim 1, characterized in that: The outlet area of ​​the evaporating coil (1) is constructed as a U-shaped tube (11) obtained by bending a straight tube section once, one end of the U-shaped tube (11) is connected to the body of the evaporating coil (1), and the other end of the U-shaped tube (11) is constructed as the outlet (111).

3. The evaporator defrosting system according to claim 2, characterized in that: The outlet (111) of the U-shaped tube (11) is configured as a gradually expanding outlet (111A).

4. The evaporator defrosting system according to claim 2, characterized in that: The evaporator defrosting system comprises a transition pipe (3), the transition pipe (3) comprising a transition inlet (31) and a transition outlet (32), the transition inlet (31) being connected to the lower connecting port (22), the transition outlet (32) being arranged toward the body of the evaporating coil (1), and the horizontal position of the transition outlet (32) being lower than the horizontal position of the lower connecting port (22).

5. The evaporator defrosting system according to claim 4, characterized in that: The transition pipe (3) comprises a first U-shaped portion (3A) and a second U-shaped portion (3B), wherein the first U-shaped portion (3A) is connected to the second U-shaped portion (3B) and is centrally symmetrically arranged.

6. The evaporator defrosting system according to claim 5, characterized in that: The top end surface of one of the first U-shaped portion (3A) and the second U-shaped portion (3B) is arranged flush with the top end surface of the U-shaped tube (11).

7. A defrosting control method, characterized in that: Using the evaporator defrosting system according to any one of claims 1 to 5, the method comprises: Controlling the heater to start at a first power to heat the evaporating coil, so that the liquid refrigerant generates liquid bubbles in the pipe opening of the evaporating coil; Determining that the heater starts for a first preset time, and controlling the heater to stop heating; Controlling the compressor to start at a preset frequency to extract the liquid-carrying bubbles accumulated at the pipe opening of the evaporating coil; Determining that the start-up time of the compressor meets the second preset time, and controlling the compressor to stop running; Repeat the above process until the liquid refrigerant meets the preset conditions.

8. The defrost control method according to claim 7, characterized in that: The preset condition includes at least one of the following: The sum of the first preset time of the heater being started multiple times is equal to the first preset time value; or Determine that the liquid refrigerant in the evaporator coil is completely vaporized; or Determining that the amount of liquid carried by the bubbles in the evaporating coil is lower than a preset value; or Determine that the generation rate of the liquid-carrying bubbles meets a preset rate range.

9. The defrost control method according to claim 7, characterized in that: The first power, the first preset time, the preset frequency and the second preset time all adopt constant values.

10. The defrost control method according to claim 7, characterized in that: During multiple startups, the first preset time gradually decreases; or, when the bubble generation rate increases, the first preset time gradually increases.

11. The defrost control method according to claim 7, characterized in that: Before the step of controlling the heater to start at the first power to heat the evaporating coil so that the liquid refrigerant generates liquid bubbles in the pipe opening of the evaporating coil, the method includes: Make sure the refrigeration equipment is in the defrost cycle and control the compressor to stop running.

12. The defrost control method according to claim 11, characterized in that: After determining that the refrigeration equipment is in a defrosting cycle and controlling the compressor to stop running, the method includes: The heater is controlled to start at a second power to heat the evaporation coil.

13. The defrost control method according to claim 11, characterized in that: A starting power of the second power is greater than the first power.

14. The defrost control method according to claim 11, characterized in that: During multiple startups, the change in the first power at which the heater is started is positively correlated with the bubble generation rate.

15. The defrost control method according to claim 11, characterized in that: After repeating the above process until the liquid refrigerant meets the preset conditions, the method includes: The heater is controlled to start at a third power to heat the evaporation coil.

16. The defrost control method according to claim 15, characterized in that: A starting power of the third power is greater than the first power.

17. The defrost control method according to claim 7, characterized in that: After repeating the above process until the liquid refrigerant meets the preset conditions, the method includes: Make sure the refrigeration equipment meets the conditions for exiting defrost, control the heater to shut down, and control the compressor to enter the refrigeration cycle.

18. The defrost control method according to claim 17, characterized in that: The defrost exit condition includes: the total time for which the heater is continuously started is greater than or equal to a second preset time value, and the second preset time value is greater than the first preset time value.

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