Refrigeration apparatus, and defrosting control method and device for refrigeration apparatus

Abstract

The present disclosure provides a refrigeration equipment, a defrosting control method and device of the refrigeration equipment, and belongs to the technical field of refrigeration equipment control; the method comprises the following steps: when a first trigger condition is met, the rotating speed of an evaporative fan and a condensing fan and the working frequency of a compressor of the refrigeration equipment are reduced, and the opening degree of an electronic expansion valve is increased to perform a first defrosting operation; when a second trigger condition is met, the working frequency of the compressor is reduced, and the opening degree of the electronic expansion valve is restored to the opening degree before the first defrosting operation to perform a drip water operation; the problems of long defrosting time and low efficiency are solved, the defrosting time can be reduced, the conditions for triggering defrosting are more close to the actual frosting degree of the evaporator, and the problems of excessive defrosting and untimely defrosting can be avoided.

Description

Technical Field

[0001] This disclosure relates to the field of refrigeration equipment control technology, and in particular to a refrigeration equipment and a defrosting control method and apparatus for the refrigeration equipment. Background Technology

[0002] After a period of use, frost will gradually form on the fins of the evaporator in refrigeration equipment (such as refrigerators and freezers). As the thickness of the accumulated frost increases, the heat transfer rate of the evaporator will decrease significantly, thus affecting the refrigeration efficiency of the equipment. To maintain the refrigeration performance of the equipment, defrosting must be performed to remove the frost.

[0003] In existing defrosting methods, the process involves shutting down the compressor and condenser fan when the cumulative power-on time or compressor running time of the refrigeration equipment reaches a preset value, while allowing the evaporator fan to run at full speed. This relies on the natural temperature rise within the refrigeration equipment to melt the frost. While simple, this method is time-consuming and inefficient. Furthermore, the refrigeration equipment cannot perform its refrigeration function during defrosting, affecting food storage. Moreover, the conditions triggering defrosting do not accurately reflect the actual degree of frost buildup on the evaporator. This can lead to over-defrosting, damaging the evaporator's lifespan, or delayed defrosting, affecting the stability of the internal temperature of the refrigeration equipment. Summary of the Invention

[0004] This disclosure provides a refrigeration equipment and a defrosting control method and apparatus for the refrigeration equipment; it can reduce the defrosting time and the conditions for triggering defrosting are closer to the actual degree of frost on the evaporator, thus avoiding over-defrosting and untimely defrosting.

[0005] The technical solution disclosed herein is implemented as follows:

[0006] In a first aspect, this disclosure provides a defrosting control device for a refrigeration equipment, comprising:

[0007] Temperature sensors are used to sense the evaporator temperature and compartment temperature of refrigeration equipment;

[0008] The controller is communicatively coupled to the temperature sensor, the evaporator fan, the condenser fan, the compressor, and the electronic expansion valve of the refrigeration equipment.

[0009] The controller is configured to: reduce the speed of the evaporator fan and condenser fan of the refrigeration equipment and the operating frequency of the compressor, and increase the opening of the electronic expansion valve to perform a first defrosting operation when a first triggering condition is met; wherein the first triggering condition includes: the evaporator temperature is less than a first evaporator temperature threshold and the compartment temperature is less than a compartment temperature threshold.

[0010] Secondly, this disclosure provides a defrosting control method for a refrigeration device, including:

[0011] When the first triggering condition is met, the speed of the evaporator fan and condenser fan of the refrigeration equipment and the operating frequency of the compressor are reduced, and the opening of the electronic expansion valve is increased to perform the first defrosting operation; wherein, the first triggering condition includes: the compartment temperature of the refrigeration equipment is less than the compartment temperature threshold and the evaporator temperature of the refrigeration equipment is less than the first evaporator temperature threshold.

[0012] When the second triggering condition is met, the operating frequency of the compressor is reduced and the opening of the electronic expansion valve is restored to the opening before the first defrosting operation to perform the dripping operation; wherein, the second triggering condition includes: the return gas pressure at the compressor return gas pipe is less than the set pressure threshold, the return gas superheat at the compressor return gas pipe is less than the set return gas superheat threshold, and the evaporator temperature is greater than the second evaporator temperature threshold, the return gas superheat is the difference between the return gas temperature and the evaporator temperature, and the second evaporator temperature threshold is greater than the first evaporator temperature threshold.

[0013] Thirdly, this disclosure provides a refrigeration device, including the defrosting control device described in the first aspect.

[0014] This disclosure provides a refrigeration device and a defrosting control method and apparatus for the refrigeration device; the defrosting operation is triggered based on the evaporator temperature and the compartment temperature, so that the conditions for triggering defrosting are closer to the actual degree of frost on the evaporator, avoiding over-defrosting and untimely defrosting. Moreover, by reducing the speed of the evaporator fan and the condenser fan and the operating frequency of the compressor, and increasing the opening of the electronic expansion valve, the defrosting operation is performed, so that the frost layer melts faster, the defrosting time is reduced, and the negative impact on the preservation effect of stored items is avoided. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the composition of the refrigeration equipment provided in this disclosure.

[0016] Figure 2 This is a schematic diagram of the composition of a defrosting control device provided in this disclosure.

[0017] Figure 3 This is a schematic diagram of a process for initiating and performing a defrosting operation as provided in this disclosure.

[0018] Figure 4 This is a schematic diagram of another defrosting control device provided in this disclosure.

[0019] Figure 5 This is a schematic diagram of a process for initiating and executing a dripping operation, as provided in this disclosure.

[0020] Figure 6 This is a schematic diagram of a defrosting control method for a refrigeration device provided in this disclosure. Detailed Implementation

[0021] The technical solutions in this disclosure will now be clearly and completely described with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram illustrating the composition of an exemplary refrigeration device 100 disclosed herein. The refrigeration device 100 involved in this disclosure can be a refrigerator, freezer, or other device capable of storing items in a refrigerated or frozen state. Figure 1 In the refrigeration equipment 100, there is a main body 110 having a front opening, a compartment 120 formed in the main body 110 for storing items, a door 130 for opening or closing the front opening of the main body 110, and a refrigeration system 140 for cooling the temperature inside the compartment 120.

[0023] The body 110 defines the appearance of the refrigeration device 100. Exemplarily, the body 110 includes an inner housing 112 for forming a compartment and an outer housing 114 coupled to the outside of the inner housing 112. An insulating material is filled between the inner housing 112 and the outer housing 114 to prevent cold air from leaking from the compartment 120.

[0024] For example, compartment 120 can be implemented as a refrigerator compartment for storing items in a refrigerated state, storing items at a temperature above zero degrees Celsius. For instance, in a refrigerated state, the temperature of compartment 120 can be maintained in a temperature range of approximately 1 to 5 degrees Celsius. Furthermore, compartment 120 can also be implemented as a freezer compartment for storing items in a frozen state, storing items at a temperature below zero degrees Celsius. For instance, in a frozen state, the temperature of compartment 120 can be maintained in a temperature range of approximately -13 to -20 degrees Celsius.

[0025] The compartment 120 can be opened or closed through the door 130. After the door 130 is closed, when the temperature inside the compartment 120, which is implemented as a refrigerator compartment, is higher than the temperature range corresponding to the refrigeration state, or when the temperature inside the compartment 120, which is implemented as a freezer compartment, is higher than the temperature range corresponding to the freezing state, the refrigeration system 140 will be activated to lower the temperature inside the compartment 120.

[0026] For example, the refrigeration system 140 includes a compressor 142, a condenser 144, an expansion valve 146, and an evaporator 148. Specifically, the compressor 142 and the condenser 144 may be arranged in the machine room at the lower rear of the main body 110. Figure 1 (Not shown). The expansion valve 146 and the evaporator 148 can be disposed in the pipes (not shown) inside the main body 110. Figure 1 (Not shown)

[0027] For example, in conjunction with the components included in the refrigeration system 140 described above, the refrigeration system 140 operates in the following modes during the process of reducing the temperature within the compartment 120 to a temperature range corresponding to the refrigeration or freezing state (i.e., the refrigeration process):

[0028] First, the compressor 142 compresses the low-pressure gaseous refrigerant to form a high-pressure gaseous refrigerant, and then transmits the high-pressure gaseous refrigerant to the condenser 144 through the refrigerant pipeline 135 under high pressure.

[0029] Subsequently, the high-pressure gaseous refrigerant is condensed into a high-pressure liquid refrigerant through condenser 144, and during this condensation process, the refrigerant releases latent heat. In some examples, the condenser 144 is heated by the latent heat released from the refrigerant; therefore, a condenser fan 143 can be configured to exhaust the released latent heat to the external environment of the refrigeration equipment 100 to cool the condenser 144.

[0030] Next, expansion valve 146 reduces the pressure of the high-pressure liquid refrigerant, and it can also regulate the amount of refrigerant so that the refrigerant can absorb sufficient heat energy from the evaporator 148. In some examples, expansion valve 146 can be implemented as an electronic expansion valve, in which case it can be controlled by a controller (…). Figure 1 Under the control of (not shown in the image) via the driver ( Figure 1 (Not shown in the image) Adjust the opening or closing state of the expansion valve 146, as well as the degree of opening (which may be simply referred to as the opening degree).

[0031] Finally, the evaporator 148 evaporates the depressurized liquid refrigerant, and during the evaporation process, the refrigerant absorbs latent heat from the evaporator 148 to cool the air surrounding the evaporator 148. In some examples, the refrigeration device 100 also includes an evaporator fan 149, which directs the air cooled by the evaporator 148 through the outlet 170 into the chamber 120 to lower the temperature inside the chamber 120, and returns the flowing air to the vicinity of the evaporator 148 through the return air vent 180.

[0032] The low-pressure gaseous refrigerant after evaporation returns to compressor 142, thus repeating the above refrigeration cycle. In some examples, the pressure generated by compressor 142 causes the refrigerant to circulate within refrigerant line 135 along condenser 144, expansion valve 146, and evaporator 148.

[0033] During the aforementioned refrigeration process, water vapor near the evaporator 148 condenses on the fins of the evaporator 148 due to cooling, thus forming a frost layer on the fins. As this frost layer accumulates, the heat transfer rate of the evaporator 148 decreases significantly, thereby affecting the refrigeration efficiency.

[0034] To eliminate the effects of frost, the evaporator 148 of the refrigeration unit 100 is typically defrosted. In some solutions, when the cumulative power-on time of the refrigeration unit 100 or the running time of the compressor 142 reaches a preset value, the compressor 142 and the condenser fan 143 are turned off, while the evaporator fan 149 runs at full speed. The frost melts naturally as the internal temperature of the compartment 120 rises. This solution is called a natural defrosting solution. In other solutions, an electric heater (not shown in the figure) is installed near the evaporator 148, and the heater is periodically activated to melt the frost on the evaporator 148. This solution is called an electric defrosting solution.

[0035] Of the aforementioned solutions, natural defrosting is slow and inefficient. Furthermore, the refrigeration unit 100 cannot operate during defrosting, affecting the stability of its internal temperature and negatively impacting the preservation of stored items. While electric defrosting can accelerate the melting of frost, the additional electric heater increases the overall energy consumption of the refrigeration unit 100. The heat generated after the electric heater starts also affects the stability of the internal temperature, negatively impacting the preservation of stored items.

[0036] To improve defrosting efficiency, reduce the overall energy consumption of refrigeration equipment, and minimize the negative impact of defrosting operations on the preservation of stored goods, this disclosure provides a defrosting control device for refrigeration equipment. Figure 2 This is a schematic diagram of the defrosting control device 200. Figure 2 In the process, the defrosting control device 200 includes a temperature sensor 210 and a controller 220 that are communicatively coupled to each other.

[0037] Temperature sensor 210 is disposed within compartment 120 of the refrigeration unit 100 to sense the temperature of compartment 120 and the temperature of evaporator 148. Specifically, temperature sensor 210 includes a first sensor 211 and a second sensor 212, wherein one or more first sensors 211 are arranged within the space of compartment 120, for example, on the inner casing 112 of compartment 120, to sense the temperature of compartment 120. Second sensor 212 is arranged at the center of evaporator 148 to sense the temperature of evaporator 148.

[0038] The controller 220 is disposed within the refrigeration equipment 100, for example, in the machine room housing the compressor 142 and the condenser 144. In addition to being communicatively coupled to the temperature sensor 210, the controller 220 is also communicatively coupled to the compressor 142, expansion valve 146, condenser fan 143, and evaporator fan 149 within the refrigeration equipment 100. Upon receiving the temperature sensed by the temperature sensor 210, the controller 220 initiates, executes, and terminates the defrosting operation by controlling the operating states of the compressor 142, expansion valve 146, condenser fan 143, and evaporator fan 149.

[0039] In this disclosure, controller 220 includes memory 221 and processor 222. Specifically, memory 221 may be implemented as random access memory (RAM), read-only memory (ROM), or non-transitory computer-readable storage medium. Processor 222 is physically implemented as a microprocessor, central processing unit (CPU), processor core, multi-core processor, multiprocessor, application-specific integrated circuit (ASIC), or field-programmable gate array (FPGA), etc.

[0040] The memory 221 is used to store temperature values ​​received from the temperature sensor 210 and programs or instructions executed by the processor 222. The processor 222 executes the programs or instructions stored in the memory 221 to enable the controller 220 to control the initiation and execution of the defrosting operation.

[0041] Figure 3 This is a schematic diagram illustrating the process of starting and executing the defrosting operation of the defrosting control device 200 provided in this disclosure. Specifically, Figure 3 The process shown is executed by the controller 220 in the defrost control device 200, and more specifically, by the processor 222 in the controller 220.

[0042] refer to Figure 3 In step S301, the controller 220 compares the evaporator temperature and the compartment temperature with the first evaporator temperature threshold and the compartment temperature threshold, respectively.

[0043] In detail, as frost accumulates on the evaporator fins, the cooling energy generated by the evaporator's heat absorption becomes increasingly difficult to cool the surrounding air due to the frost's obstruction, causing a gradual decrease in heat exchange efficiency between the evaporator and the air. Because more cooling energy remains in the evaporator and cannot be carried away by the air, the evaporator temperature further decreases, leading to a further thickening of the frost layer on the fins, thus increasing the urgency of defrosting. In light of these factors, this disclosure uses whether the evaporator temperature reaches a set first evaporator temperature threshold as a condition to trigger the defrosting operation. This first evaporator temperature threshold indicates whether the frost layer on the evaporator fins has accumulated to a certain thickness. For example, when the evaporator temperature is below 0 degrees Celsius, water vapor near the evaporator will condense to form a frost layer, and as the evaporator temperature gradually decreases due to the frost, the frost layer will gradually accumulate and thicken. In this disclosure, the temperature threshold of the first evaporator is set in the range of -15°C to -5°C. This setting ensures that the refrigeration equipment performs defrosting operation when needed, and also ensures that a certain thickness of frost layer has accumulated on the evaporator to prevent defrosting from occurring when there is no frost.

[0044] Furthermore, even with the same evaporator temperature, different compartment temperatures can lead to inconsistent frost thickness. For example, in the initial stage of the cooling process, the compartment temperature is high, and the compressor is operating at full load. In this situation, even if the evaporator temperature is low, the water vapor condensed on the fins will melt due to the higher compartment temperature and the air circulation within the compartment, preventing frost formation. Therefore, this disclosure uses whether the compartment temperature reaches a set compartment temperature threshold as another condition for triggering the defrosting operation. This compartment temperature threshold indicates whether frost will form on the fins when the evaporator temperature is low. In this disclosure, the compartment temperature threshold is set below a pull-down temperature, which is used to determine the temperature state within the compartment. For example, when the compartment temperature is higher than the pull-down temperature, the evaporator fan, condenser fan, and compressor frequency will operate at their maximum values ​​to achieve rapid temperature increase. In this disclosure, the compartment temperature threshold is set in a range less than 10 degrees Celsius, for example, -3°C.

[0045] Combining the two thresholds above, this disclosure uses the condition that the evaporator temperature is less than the first evaporator temperature threshold and the compartment temperature is less than the compartment temperature threshold as the condition for triggering the defrosting operation, which will also be referred to as the first triggering condition in the following content.

[0046] In step S302, when the evaporator temperature is less than the first evaporator temperature threshold and the compartment temperature is less than the compartment temperature threshold, the first defrosting operation is performed.

[0047] In this disclosure, when the condition for triggering the defrost operation (i.e. the first trigger condition) is met, the controller 220 initiates the first defrost operation and, compared to the refrigeration process, performs the first defrost operation by reducing the speed of the evaporator fan and condenser fan of the refrigeration equipment, reducing the operating frequency of the compressor, and increasing the opening of the electronic expansion valve.

[0048] In detail, the controller 220 transmits drive commands to the evaporator fan, condenser fan, compressor, and electronic expansion valve of the refrigeration equipment. These drive commands are used to drive the evaporator fan and condenser fan to operate at the speed corresponding to the first defrost operation, the compressor to operate at the operating frequency corresponding to the first defrost operation, and the electronic expansion valve to operate at the opening degree corresponding to the first defrost operation.

[0049] Compared to the normal cooling process of a refrigeration system, reducing the speed of the condenser fan during the first defrost operation reduces the latent heat discharged to the external environment and weakens the condensation process, thereby reducing refrigerant heat loss. Furthermore, the condensation process transforms the refrigerant from a gaseous phase to a liquid phase. By reducing the condenser fan speed to weaken the condensation process, the proportion of liquid refrigerant in the refrigeration system decreases, while the proportion of gaseous refrigerant increases. This also reduces the risk of liquid slugging in the compressor.

[0050] Increasing the opening of the electronic expansion valve increases the refrigerant flow rate in the refrigeration system. As a result, more refrigerant flows in the evaporator per unit time, which generates more heat for defrosting and improves defrosting efficiency.

[0051] Reducing the speed of the evaporator fan can reduce the heat exchange between the high-temperature refrigerant in the evaporator and the air in the refrigeration equipment room, thus reducing the heat carried away by the refrigerant. This results in the refrigerant in the evaporator having more heat to melt the frost on the fins.

[0052] During the first defrosting operation, the compressor's operating frequency is lower than during the refrigeration process. This is because: firstly, a lower compressor operating frequency results in poorer lubricating oil return within the compressor and reduces the refrigerant flow circulating in the refrigeration system per unit time, thus degrading the defrosting effect. Secondly, a higher compressor operating frequency causes the compressor to operate at a higher frequency for extended periods, affecting its reliability and lifespan.

[0053] Based on the above description, in this disclosure, during the first defrosting operation, the controller 220 drives the condenser fan 143 and the evaporator fan 149 to stop, adjusts the opening of the electronic expansion valve to its maximum, and adjusts the compressor's operating frequency so that the difference between the compressor's operating frequency and the center frequency of its operating frequency range is less than a set frequency threshold. For example, if the compressor's operating frequency range is 20Hz to 120Hz, and its center frequency is 70Hz, during the first defrosting operation, the compressor's operating frequency is adjusted to be slightly higher than this center frequency, such as 80Hz to 100Hz.

[0054] In this disclosure, to prevent frequent execution of the first defrost operation or defrosting in the absence of frost, the first triggering condition further includes: the duration from the end of the previous first defrost operation to the current moment is greater than or equal to a set first duration threshold. For example, the first duration threshold is set in the range of 6 to 12 hours. This setting allows the refrigeration system to operate normally without affecting the normal use of the refrigeration equipment due to excessively frequent defrosting.

[0055] In this disclosure, in addition to the aforementioned first defrosting operation, other defrosting methods are not excluded, such as natural defrosting and electric defrosting, which can be referred to as the second defrosting operation. In this disclosure, the first defrosting operation is initiated when the frost layer is thin. As the number of executions increases, there is a risk that the frost layer will become thicker. Therefore, the controller 220 records the number of times the first defrosting operation is executed. When the number of executions N1 of the first defrosting operation reaches a set threshold N2, the controller 220 performs defrosting through the second defrosting operation, resets the number of executions of the first defrosting operation to zero, and re-records the number of executions of the first defrosting operation. In other words, the combined use of the first and second defrosting operations can improve the operating efficiency and stability of the refrigeration system.

[0056] During the first defrost operation, some of the high-temperature, high-pressure refrigerant at the compressor outlet will condense and be delivered to the evaporator inlet without throttling. Thus, the refrigerant temperature inside the evaporator is expected to be between 30-50°C. Compared to natural defrosting, which relies on the natural rise of the air temperature inside compartment 120 (around 0°C), the first defrost operation melts the frost much faster. Furthermore, during the first defrost operation, there is no need to use an electric heater for melting, reducing the overall energy consumption of the refrigeration equipment compared to electric defrosting. It also avoids the impact of heat generated by the electric heater on the internal temperature stability of the refrigeration equipment 100, and reduces the negative impact on the preservation of stored items.

[0057] Understandably, after the frost on the evaporator fins melts during the first defrost operation, the refrigeration system cannot operate immediately, and the defrost water obtained from the defrost operation needs to be discharged from the evaporator. The process of discharging defrost water from the evaporator can also be called the dripping operation. In addition to initiating and executing the first defrost operation, the defrost control device 200 also terminates the first defrost operation and switches to the dripping operation. Based on this, as... Figure 4 A schematic diagram of another defrosting control device 200 is shown. Figure 4 In the defrosting control device 200 shown, the temperature sensor 210 further includes a third sensor 213, and the defrosting control device 200 also includes a pressure sensor 230. Specifically, the third sensor 213 is located at the return pipe of the compressor 142 to sense the return air temperature at the compressor's return pipe. The pressure sensor 230 is also located at the return pipe of the compressor 142 to sense the return air pressure value at the compressor's return pipe. The controller 220 is communicatively coupled to the third sensor 213 and the pressure sensor 230 to receive the return air temperature and return air pressure values, and controls the initiation, execution, and termination of the dripping operation by executing the program or instructions stored in the memory 221.

[0058] Figure 5 This is a schematic diagram illustrating the process of starting and performing a dripping operation of the defrosting control device 200 provided in this disclosure. Specifically, Figure 5 The process shown is executed by the controller 220 in the defrost control device 200, and more specifically, by the processor 222 in the controller 220.

[0059] refer to Figure 5 In step S501, the controller compares the return gas pressure value, return gas superheat, and evaporator temperature with the pressure value threshold, the return gas superheat threshold, and the second evaporator temperature threshold, respectively.

[0060] During the first defrost operation, the electronic expansion valve opens to its maximum, increasing the refrigerant flow. Furthermore, the evaporator fan speed decreases or stops to prevent heat from flowing into the room, which reduces the evaporator's heat exchange efficiency. Combined, these two factors lead to a decrease in the dryness of the refrigerant at the evaporator outlet, meaning a lower proportion of gaseous refrigerant in the two-phase refrigerant system. This increases the risk of liquid slugging in the compressor. During evaporation, the liquid refrigerant gradually transforms into gaseous refrigerant through heat exchange with air in the heat exchanger, causing a gradual increase in refrigerant dryness. The reduced or stopped evaporator fan speed during the first defrost operation further degrades the evaporator's heat exchange effect, resulting in a lower refrigerant dryness at the evaporator outlet compared to normal refrigeration. This disclosure utilizes the return gas superheat and return gas pressure at the compressor return pipe to determine whether to terminate the first defrost operation, thereby reducing the risk of liquid slugging in the compressor. Specifically, the return gas superheat is the difference between the return gas temperature and the evaporator temperature. Lower return gas superheat and return gas pressure values ​​indicate lower refrigerant dryness at the compressor return pipe, a higher proportion of liquid refrigerant, and a greater risk of liquid slugging. Lower return gas pressure means a smaller evaporator heat exchange temperature difference, resulting in insufficient refrigerant vaporization (lower dryness). Therefore, this disclosure sets pressure thresholds and return gas superheat thresholds to characterize lower dryness. Whether the return gas pressure is less than the pressure threshold and whether the return gas superheat is less than the return gas superheat threshold are used as conditions for increased liquid slugging risk. This condition is one of the conditions for ending the defrosting operation and triggering the dripping operation. For example, the return gas superheat threshold is set to 5 degrees Celsius. Under this temperature condition, the proportion of refrigerant vaporized at the evaporator outlet is relatively high, even reaching complete vaporization. This prevents liquid refrigerant from entering the compressor, reducing the risk of liquid slugging. Taking R404A refrigerant as an example, when the return gas pressure is less than 0.12 MPa, the refrigerant dryness at the return gas port decreases and the liquid phase ratio increases, which greatly increases the risk of liquid slugging in the compressor. Therefore, it is necessary to set a return gas pressure monitoring range to monitor the refrigerant status.

[0061] The return gas pressure value is determined by the type of refrigerant used in the refrigeration system. Taking R404A refrigerant as an example, when the return gas pressure is less than 0.12 MPa, the dryness of the refrigerant at the return gas port decreases and the proportion of liquid phase increases, which greatly increases the risk of liquid slugging in the compressor. Therefore, it is necessary to set a return gas pressure monitoring range to monitor the refrigerant status. In this disclosure, the return gas pressure threshold is set in the range of 0.12 MPa to 0.20 MPa.

[0062] Furthermore, as the defrosting operation is performed, the frost layer on the evaporator fins gradually melts, and the evaporator temperature becomes higher than when the frost layer had accumulated. Understandably, when the evaporator temperature rises to a set temperature, the frost layer on the evaporator fins has completely melted. The evaporator temperature is still sensed by the second sensor 212. This disclosure uses whether the evaporator temperature exceeds a second evaporator temperature threshold as another condition for ending the defrosting operation and triggering the dripping operation. Understandably, the second evaporator threshold is greater than the first evaporator threshold, for example, 15 degrees Celsius. This setting allows the frost layer to melt completely while preventing a significant rise in the temperature inside the compartment, thus avoiding a negative impact on the preservation of stored items.

[0063] Combining the above three thresholds, this disclosure uses whether the return gas pressure is less than the pressure threshold, whether the return gas superheat is less than the return gas superheat threshold, and whether the evaporator temperature is greater than the second evaporator temperature threshold as the conditions for ending the defrosting operation and triggering the dripping operation, which will also be referred to as the second triggering condition in the following content.

[0064] In step S502, when the return gas pressure is less than the pressure threshold, the return gas superheat is less than the return gas superheat threshold, and the evaporator temperature is greater than the second evaporator temperature threshold, the dripping operation is performed.

[0065] In this disclosure, when the condition for triggering the dripping operation (i.e., the second triggering condition) is met, the controller 220 starts the dripping operation. Compared with the aforementioned first defrosting operation, the controller 220 performs the dripping operation by reducing the operating frequency of the compressor and restoring the opening of the electronic expansion valve to the opening before the first defrosting operation.

[0066] In detail, the dripping operation signifies that the frost layer on the evaporator has completely melted, and the defrosting process is complete. At this point, no further heat is needed to supply the evaporator. Therefore, the compressor's operating frequency is further reduced from the frequency during the first defrosting operation to protect the compressor and prevent liquid slugging during the discharge of defrost water. Furthermore, to prevent compressor damage, a certain interval is required before the next normal operation, during which the dripping operation is performed to completely drain the defrost water from the evaporator.

[0067] During the dripping operation, the opening of the electronic expansion valve will gradually return from the opening during the first defrost operation to the opening during normal operation (i.e., the refrigeration process) before the first defrost operation. Understandably, the opening of the electronic expansion valve during the first defrost operation is greater than the opening during normal operation. During the dripping operation, the controller 220 will gradually reduce the opening of the electronic expansion valve to return it to the opening during normal operation.

[0068] Based on the above explanation, during the dripping operation, the controller 220 drives the compressor to stop and reduces the opening of the electronic expansion valve from its maximum opening to the opening before the first defrost operation, according to a set step size. For example, if the maximum opening of the electronic expansion valve is set to 480° and the normal operating opening before the first defrost operation is 80°, the controller 220 can gradually reduce the opening of the electronic expansion valve in steps of 20° every 5 seconds. In this way, the electronic expansion valve will return to its normal operating opening within 100 seconds. This avoids excessively rapid pressure changes within the refrigeration system without causing excessive delays.

[0069] In this disclosure, to prevent the aforementioned three second triggering conditions from failing, the execution duration of the first defrosting operation can also be set as a condition for triggering the dripping operation. That is, the second triggering condition also includes: the execution duration of the first defrosting operation is longer than a set second duration threshold. In this disclosure, the second duration threshold is set in the range of 3 to 5 minutes. This setting can prevent the execution duration of the first defrosting operation from being too short, thus reducing the defrosting effect, and also prevent the execution duration of the first defrosting operation from being too long, thus increasing the risk of liquid slugging in the compressor.

[0070] During the dripping operation, it is essential to ensure that defrost water is drained smoothly and promptly, while also avoiding prolonged operation that could negatively impact the preservation of stored items. This disclosure sets a duration for the dripping operation; once this duration is met, the refrigeration system resumes its refrigeration process, i.e., normal operation. In this disclosure, this duration is set based on the volume of the room and the type of refrigeration system, and is typically set to 3 minutes.

[0071] Based on the same concept as the aforementioned technical solutions, this disclosure provides a defrosting control method for refrigeration equipment. Figure 6 This is a flowchart illustrating the defrosting control method. The defrosting control method is executed by the defrosting control device 200 in the aforementioned technical solution, and in particular, the controller 220 in the defrosting control device 200.

[0072] See Figure 6 In step S601, when the first triggering condition is met, the speed of the evaporator fan and condenser fan of the refrigeration equipment and the operating frequency of the compressor are reduced, and the opening of the electronic expansion valve is increased to perform the first defrosting operation.

[0073] In this disclosure, the first triggering condition includes: the room temperature of the refrigeration equipment is less than the room temperature threshold and the evaporator temperature of the refrigeration equipment is less than the first evaporator temperature threshold;

[0074] In step S602, when the second triggering condition is met, the operating frequency of the compressor is reduced and the opening of the electronic expansion valve is restored to the opening before the first defrosting operation to perform the dripping operation.

[0075] In this disclosure, the second triggering conditions include: the return gas pressure at the compressor return pipe is less than a set pressure threshold, the return gas superheat at the compressor return pipe is less than a set return gas superheat threshold, and the evaporator temperature is greater than a second evaporator temperature threshold. The return gas superheat is the difference between the return gas temperature and the evaporator temperature, and the second evaporator temperature threshold is greater than the first evaporator temperature threshold.

[0076] for Figure 6 The defrosting control method shown in the figure involves the following steps during the first defrosting operation: the evaporator fan and condenser fan of the refrigeration equipment are stopped, the difference between the operating frequency of the compressor and the center frequency of the operating frequency range is less than the set frequency threshold, and the opening degree of the electronic expansion valve is at its maximum.

[0077] for Figure 6 The defrosting control method shown includes a first triggering condition that the duration from the end of the previous first defrosting operation to the current time is greater than or equal to a set first duration threshold.

[0078] for Figure 6 The defrosting control method shown in the figure involves shutting down the compressor during the dripping operation and reducing the opening of the electronic expansion valve from the maximum opening to the opening before the first defrosting operation according to the set step opening.

[0079] for Figure 6 The defrosting control method shown includes a second triggering condition: the execution duration of the first defrosting operation is greater than a set second duration threshold.

[0080] This disclosure also provides a computer-readable storage medium storing at least one instruction that is executed by a processor to implement the defrosting control method as described in the above embodiments.

[0081] This disclosure also provides a computer program product including computer instructions stored in a computer-readable storage medium; a processor of a computing device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computing device to perform the defrosting control method described in the above embodiments.

[0082] Those skilled in the art will recognize that the functions described in this disclosure in one or more of the examples above can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium accessible to a general-purpose or special-purpose computer.

[0083] It should be noted that the technical solutions described in this disclosure can be combined arbitrarily as long as they do not conflict.

[0084] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A defrosting control device for refrigeration equipment, characterized in that, The defrosting control device is applied to a refrigeration equipment, and the defrosting control device includes: A temperature sensor is used to sense the evaporator temperature and the compartment temperature of the refrigeration equipment. The controller is communicatively coupled to the temperature sensor, the evaporator fan, the condenser fan, the compressor, and the electronic expansion valve of the refrigeration equipment, respectively. The controller is configured to: when a first trigger condition is met, reduce the speed of the evaporator fan and condenser fan of the refrigeration equipment and the operating frequency of the compressor, and increase the opening of the electronic expansion valve to perform a first defrosting operation; wherein the first trigger condition includes: the evaporator temperature is less than a first evaporator temperature threshold and the compartment temperature is less than a compartment temperature threshold.

2. The defrosting control device according to claim 1, characterized in that, During the first defrosting operation, the evaporator fan and condenser fan of the refrigeration equipment are stopped, the difference between the operating frequency of the compressor and the center frequency of the operating frequency range is less than the set frequency threshold, and the opening of the electronic expansion valve is at its maximum.

3. The defrosting control device according to claim 1, characterized in that, The first triggering condition also includes the time elapsed from the end of the previous first defrosting operation to the current time being greater than or equal to a set first time threshold.

4. The defrosting control device according to any one of claims 1 to 3, characterized in that, The defrosting control device further includes a pressure sensor installed at the return gas pipe of the compressor for detecting the return gas pressure value at the return gas pipe of the compressor, and a temperature sensor for sensing the return gas temperature at the return gas pipe of the compressor; the controller is also communicatively coupled to the pressure sensor and configured to: when a second trigger condition is met, reduce the operating frequency of the compressor and restore the opening of the electronic expansion valve to the opening before the first defrosting operation to perform a dripping operation; wherein, the second trigger condition includes: the return gas pressure value is less than a set pressure value threshold, the return gas superheat is less than a set return gas superheat threshold, and the evaporator temperature is greater than a second evaporator temperature threshold, the return gas superheat is the difference between the return gas temperature and the evaporator temperature, and the second evaporator temperature threshold is greater than the first evaporator temperature threshold.

5. The defrosting control device according to claim 4, characterized in that, During the dripping operation, the compressor is turned off, and the opening of the electronic expansion valve is reduced from the maximum opening to the opening before the first defrosting operation according to the set step opening.

6. The defrosting control device according to claim 5, characterized in that, The second triggering condition also includes: the execution duration of the first defrosting operation is greater than the set second duration threshold.

7. A defrosting control method for a refrigeration device, characterized in that, The method includes: When the first triggering condition is met, the speed of the evaporator fan and condenser fan of the refrigeration equipment and the operating frequency of the compressor are reduced, and the opening of the electronic expansion valve is increased to perform the first defrosting operation; wherein, the first triggering condition includes: the compartment temperature of the refrigeration equipment is less than the compartment temperature threshold and the evaporator temperature of the refrigeration equipment is less than the first evaporator temperature threshold. When the second triggering condition is met, the operating frequency of the compressor is reduced and the opening of the electronic expansion valve is restored to the opening before the first defrosting operation to perform the dripping operation; wherein, the second triggering condition includes: the return gas pressure value at the return gas pipe of the compressor is less than the set pressure value threshold, the return gas superheat at the return gas pipe of the compressor is less than the set return gas superheat threshold, and the evaporator temperature is greater than the second evaporator temperature threshold, wherein the return gas superheat is the difference between the return gas temperature and the evaporator temperature, and the second evaporator temperature threshold is greater than the first evaporator temperature threshold.

8. The method according to claim 7, characterized in that, During the first defrosting operation, the evaporator fan and condenser fan of the refrigeration equipment are stopped, the difference between the operating frequency of the compressor and the center frequency of the operating frequency range is less than the set frequency threshold, and the opening of the electronic expansion valve is at its maximum.

9. The method according to claim 7, characterized in that, During the dripping operation, the compressor is turned off, and the opening of the electronic expansion valve is reduced from the maximum opening to the opening before the first defrosting operation according to the set step opening.

10. A refrigeration device, characterized in that, The refrigeration equipment includes the defrosting control device as described in any one of claims 1 to 6.

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