Refrigeration system, control method and display cabinet for defrosting an evaporator

Abstract

The application discloses a refrigeration system, a control method and a display cabinet for defrosting of an evaporator, and comprises a refrigeration module and an evaporating chamber state measurement and control module. The evaporating chamber state measurement and control module comprises a central processing unit, a fourth temperature monitoring element, a switch door inductor, an evaporating fan rotating speed regulating element, a first humidity monitoring element, first, second and third temperature monitoring elements and a second humidity monitoring element. The first, second and third temperature monitoring elements are installed on the surface of the evaporator, and the first and second humidity monitoring elements are installed on the upper sides of the evaporating chamber. The evaporating fan rotating speed regulating element is used for regulating the rotating speed of the evaporating fan, and the fourth temperature monitoring element is installed in the middle of the evaporating chamber and used for monitoring the temperature of the evaporating chamber. On the basis of not changing the refrigeration performance, the excessive frosting problem of the existing display cabinet is fundamentally solved, the heat exchange efficiency of the evaporator is improved, the service life of the equipment is prolonged, the system energy consumption is reduced, and the refrigeration effect is improved.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment technology, and in particular to a refrigeration system, control method and display case for evaporator defrosting. Background Technology

[0002] Refrigerated display cases are prone to severe frosting issues during use. Because the evaporator temperature drops rapidly upon startup, the relative humidity inside the case doesn't decrease quickly enough, and condensate doesn't drain promptly, leading to rapid frosting. Since these display cases are primarily for commercial use, frequent door opening and closing slows down the relative humidity drop, further exacerbating frosting and even ice formation. Moderate frosting increases the roughness of the evaporator surface, which helps improve the heat transfer coefficient and promotes heat exchange. However, excessive frosting forms a thick layer of frost or even ice, increasing thermal resistance and reducing heat transfer efficiency. Severe frosting can prevent the entire refrigeration or air conditioning system from operating properly, affecting equipment performance and efficiency. Excessive frosting also increases energy consumption, requiring more energy to maintain operation, potentially increasing operating costs and energy consumption. Furthermore, excessive frosting leads to uneven evaporator surface temperature, causing frequent formation and melting of condensate and frost, thus accelerating evaporator aging and corrosion. To reduce the damage caused by evaporator frosting, measures are typically taken, such as optimizing system design, controlling environmental conditions, and regular maintenance and cleaning, to ensure efficient operation and long-term stability of the equipment. Current technologies often employ methods such as electric heating defrosting, hot gas defrosting, manual defrosting, and periodic power-off defrosting. These methods all involve defrosting after frost has formed, failing to fundamentally prevent excessive frosting. This not only increases additional costs and energy consumption but also yields unsatisfactory defrosting results. Summary of the Invention

[0003] To overcome the aforementioned problems in existing technologies, this invention proposes a refrigeration system, control method, and display cabinet for evaporator defrosting. Without altering the refrigeration performance, it fundamentally solves the problem of excessive frosting in existing display cabinets, improves the heat exchange efficiency of the evaporator, extends equipment lifespan, reduces system energy consumption, and enhances the refrigeration effect.

[0004] The technical solution adopted by the present invention to solve its technical problem is: a refrigeration system for evaporator defrosting, including a compressor, a condenser, a dryer filter, an evaporator, a water collection tray, and an evaporation fan. The compressor, condenser, dryer filter, and evaporator are connected in sequence. The evaporation fan is installed on the rear side of the evaporator. The condenser connecting pipe is located in the water collection tray. The water collection tray is used to collect condensate flowing out of the evaporator surface. The system also includes an electronic expansion valve and an evaporation chamber status monitoring and control module. An electronic expansion valve is provided between the dryer filter and the evaporator.

[0005] The evaporation chamber status monitoring and control module includes a central processing unit, a fourth temperature monitoring element, a door opening / closing sensor, an evaporator fan speed control element, a first humidity monitoring element, a first temperature monitoring element, a second temperature monitoring element, a third temperature monitoring element, and a second humidity monitoring element. The first, second, and third temperature monitoring elements are mounted on the surface of the evaporator, and the first and second humidity monitoring elements are mounted on the upper sides of the evaporation chamber. The evaporator fan speed control element is used to control the evaporator fan speed. The door opening / closing sensor is used to monitor the opening / closing status of the display cabinet door. The fourth temperature monitoring element is installed in the middle of the evaporation chamber to monitor the temperature of the evaporation chamber. The fourth temperature monitoring element, the door opening / closing sensor, the evaporator fan speed control element, the first humidity monitoring element, the first temperature monitoring element, the second temperature monitoring element, the third temperature monitoring element, the second humidity monitoring element, and the electronic expansion valve are all electrically connected to the central processing unit.

[0006] The aforementioned evaporator defrosting refrigeration system has an evaporator surface coated with a hydrophobic coating.

[0007] In the aforementioned refrigeration system for evaporator defrosting, a liquid storage pipe is provided between the evaporator and the compressor. The liquid storage pipe is used to adapt to changes in the liquid supply demand caused by variations in the evaporator load.

[0008] A control method for an evaporator defrosting refrigeration system, based on the aforementioned evaporator defrosting refrigeration system, specifically includes: when the display cabinet door is detected to be open and the system is in the startup phase, after the door opening / closing sensor detects that the door is closed, determining whether the absolute humidity of the evaporation chamber is greater than 5.01 g / m³. 3 If it is greater than 5.01 g / m 3 Then, the central processing unit controls the electronic expansion valve to reduce its opening, the compressor power to decrease, and the evaporator surface temperature to drop to 0.5-1℃. The evaporator fan maintains high-speed operation, ensuring that water vapor condenses in the evaporation chamber without forming frost, until the absolute humidity of the evaporation chamber is less than or equal to 5.01 g / m³. 3 When the electronic expansion valve opens higher, the evaporator fan speed decreases. Based on the real-time results from the fourth temperature monitoring element, the central processing unit controls each component to make adjustments, ensuring stable system operation.

[0009] When the display case door is detected to be open but the system is in a stable phase, the evaporator fan speed increases to create an air curtain, reducing the amount of hot and humid air entering the evaporation chamber. Once the door sensor detects that the door is closed, it is determined whether the absolute humidity in the evaporation chamber exceeds 5.01 g / m³. 3 If it is greater than 5.01 g / m 3Then, the central processing unit controls the electronic expansion valve to reduce its opening, the compressor power to decrease, and the evaporator surface temperature to drop to 0.5-1℃. The evaporator fan maintains high-speed operation, ensuring that water vapor condenses in the evaporation chamber without forming frost, until the absolute humidity of the evaporation chamber is less than or equal to 5.01 g / m³. 3 When the electronic expansion valve opens higher, the evaporator fan speed decreases. Based on the real-time results from the fourth temperature monitoring element, the central processing unit controls each component to make adjustments, and the system operates stably until the next door opening, repeating the above control process.

[0010] The above-mentioned control method for an evaporator defrosting refrigeration system involves the following steps: When the system is in the start-up phase, the door opening / closing monitoring element detects that the cabinet door is open. The specific control process is as follows: the evaporator fan is turned on to its highest speed, the compressor maintains high power, and the electronic expansion valve maintains a high opening degree. After the system detects that the door is closed, the central processing unit collects data from the first, second, third, first, second, and fourth temperature monitoring elements, and derives the absolute humidity of the evaporator surface and the optimal system solution based on this data.

[0011] The absolute humidity is 44 g / m³ 3 In the above, the evaporator fan is kept at a high speed, the compressor is switched to low power, the electronic expansion valve is switched to a low opening, and the opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 15 minutes.

[0012] The absolute humidity is between 34 and 44 g / m³. 3 The evaporator fan is kept at high speed, the compressor is switched to low power, the electronic expansion valve is switched to low opening, and the opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 12 minutes.

[0013] The absolute humidity is between 23 and 34 g / m³. 3 At this time, the evaporator fan switches to a higher speed, the compressor switches to a lower power, the electronic expansion valve switches to a lower opening, and the opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 9 minutes.

[0014] The absolute humidity is between 5.01 and 23 g / m³. 3 At this time, the evaporator fan maintains a high speed, the compressor switches to medium power, the electronic expansion valve opens to a low degree and adjusts the opening according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 6 minutes.

[0015] Absolute humidity ≤ 5.01 g / m³3 At this time, the evaporator fan switches to medium speed, the compressor switches to the highest speed, and the electronic expansion valve maintains the highest opening until the temperature requirement is met.

[0016] The above-described control method for an evaporator defrosting refrigeration system involves the following steps: When the system is in a stable phase, the door sensor detects that the cabinet door is open, and the evaporator fan speed increases. After the cabinet door is closed, the fourth temperature monitoring element detects that the internal temperature fluctuation is ≥2℃, and the evaporator fan switches to its highest speed. The central processing unit collects data from the first, second, third, first, second, and fourth temperature monitoring elements, and calculates the absolute humidity of the evaporator surface and the optimal system solution based on this data.

[0017] The absolute humidity is 44 g / m³ 3 In the above steps, the evaporator fan switches to high speed, the compressor switches to low power, the electronic expansion valve switches to low opening, and the opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 12 minutes.

[0018] The absolute humidity is between 34 and 44 g / m³. 3 The evaporator fan switches to high speed, the compressor switches to low power, the electronic expansion valve switches to low opening, and the opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 9 minutes.

[0019] The absolute humidity is between 23 and 34 g / m³. 3 At this time, the evaporator fan switches to a higher speed, the compressor switches to a lower power, the electronic expansion valve switches to a lower opening, and the opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 6 minutes.

[0020] The absolute humidity is between 5.01 and 23 g / m³. 3 At this time, the evaporator fan switches to a higher speed, the compressor switches to medium power, the electronic expansion valve switches to a lower opening, and the opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 3 minutes.

[0021] When absolute humidity ≤ 5.01 g / m 3 At this time, the evaporator fan switches to the medium speed, while the status of other components remains unchanged.

[0022] A display case employs the control method of the aforementioned evaporator defrosting refrigeration system.

[0023] The beneficial effects of this invention are that it effectively controls the degree of frost formation on the surface of the evaporator in the refrigerated display case, preventing the negative impacts caused by excessive frost or even ice buildup. It also improves energy efficiency and performance: excessive frost increases the thickness of the insulation layer on the evaporator surface, leading to a decrease in heat transfer efficiency and thus affecting the energy efficiency of the equipment. Reducing frost formation ensures that the evaporator can transfer heat more effectively, thereby improving the overall performance of the system.

[0024] Extending equipment lifespan: Excessive frosting can cause ice buildup on the evaporator surface, potentially leading to corrosion, mechanical damage, or other problems, thus shortening the equipment's lifespan. Reducing frosting can lower maintenance and replacement costs and extend the equipment's lifespan.

[0025] Ensuring stable system operation: Excessive frosting can lead to system instability or even malfunction. Maintaining a small amount of frost on the evaporator surface ensures stable system operation, reduces maintenance and repair costs, and improves system reliability.

[0026] Improve the cleanliness of the cabinet: Frosty surfaces may breed bacteria or other harmful substances. Reducing frost can improve air quality, reduce air pollution inside the cabinet, and ensure the cleanliness and appearance of the goods inside. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Figure 1 This is a component arrangement diagram of the present invention;

[0029] Figure 2 This is a schematic diagram of the defrosting system of the present invention;

[0030] Figure 3 This is the control logic diagram of the central processing unit of this invention.

[0031] The components are as follows: 1. Compressor; 2. Dryer filter; 3. Condenser fan; 4. Bottom-mounted condenser; 5. Central processing unit; 6. Fourth temperature monitoring element; 7. Door opening / closing sensor; 8. Evaporator fan; 9. Evaporator fan speed control element; 10. First humidity monitoring element; 11. Liquid storage pipe; 12. First temperature monitoring element; 13. Second temperature monitoring element; 14. Evaporator; 15. Third temperature monitoring element; 16. Second humidity monitoring element; 17. Water collection tray; 18. Electronic expansion valve; 19. Drain pipe; 20. Condenser connecting pipe. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] To effectively reduce severe frost formation caused by rapid evaporator temperature drop during refrigeration system startup and frequent door opening and closing, and to avoid the problems of poor heat exchange and increased energy consumption resulting from frost formation, this embodiment provides a novel evaporator defrosting design scheme and operating strategy for a display cabinet refrigeration system. Figure 1-2 As shown, its system structure mainly includes a refrigeration module and an evaporator compartment status monitoring and control module. The refrigeration system mainly consists of a compressor 1, a dryer filter 2, a condenser fan 3, a bottom-mounted condenser 4, an evaporator fan 8, a liquid receiver pipe 11, an evaporator 14, a water collection pan 17, an electronic expansion valve 18, a drain pipe 19, and a condenser connecting pipe 20.

[0034] The evaporation chamber status monitoring and control system consists of a central processing unit 5, a fourth temperature monitoring element 6, a door opening and closing sensor 7, an evaporator fan speed control element 9, a first humidity monitoring element 10, a first temperature monitoring element 12, a second temperature monitoring element 13, a third temperature monitoring element 15, and a second humidity monitoring element 16.

[0035] A first humidity monitoring element and a second humidity monitoring element are arranged on the upper two sides of the evaporation chamber. A first temperature monitoring element, a second temperature monitoring element, and a third temperature monitoring element are arranged on the evaporator surface, located at the left, center, and right positions, respectively. The system collects temperature and humidity data from the evaporation chamber in real time and transmits the data to the central processing unit (CPU). The CPU then issues instructions to other components based on the analyzed real-time data. To improve system accuracy, the number of temperature and humidity monitoring elements can be further increased; however, to ensure the reference value and accuracy of the data, a geometrically symmetrical arrangement and a central axis arrangement are adopted.

[0036] The evaporator surface is coated with a hydrophobic layer to ensure that condensate collects on its surface and flows out along the drain pipe into the water collection pan. The water collection pan is heated by the bottom-mounted condenser connecting pipe to promote the evaporation of water.

[0037] The evaporator fan features multiple power output levels. Equipped with a speed control element, it receives adjustment commands from the central processing unit to regulate the speed of the variable frequency evaporator fan, thereby adjusting the airflow within the display case. The number of evaporator fans can be increased according to actual load requirements. The central processing unit analyzes the temperature and humidity inside the case and issues commands to all speed control elements.

[0038] The refrigeration system uses an electronic expansion valve for flow regulation. It receives instructions from the central processing unit to adjust the refrigerant flow, thereby controlling the evaporator surface temperature. The electronic expansion valve opening levels correspond to the variable frequency fan levels, with five levels: high, relatively high, medium, low, and relatively low.

[0039] The central processing unit (CPU) receives real-time data from the humidity and temperature control devices and issues control commands to the speed control element and electronic expansion valve based on this data. The basic control principle of the CPU is as follows: the temperature and humidity sensors transmit the relative humidity and temperature data of the evaporation chamber to the CPU in real time. The CPU analyzes this data to determine the absolute humidity inside the cabinet. When the absolute humidity is high, such as during cabinet startup or door opening, the CPU commands the electronic expansion valve to reduce the valve opening, decreasing the system flow rate. This reduces the system's cooling capacity, keeping the evaporator surface temperature within the optimal range above zero degrees Celsius (0.5~1℃). This causes rapid condensation of the humid air in the evaporation chamber, reaching 100% relative humidity and a rapid decrease in absolute humidity. Simultaneously, to ensure the rapid temperature increase of the display cabinet, the CPU commands the speed control element to increase the evaporator fan speed. This increased airflow compensates for the rising evaporator temperature, ensuring a constant cooling capacity inside the cabinet. After the condensed dew flows out through the pipes, the central processing unit sends commands to the electronic expansion valve and speed control element, causing the valve opening to increase and the variable frequency fan speed to decrease, restoring normal cooling. This achieves a decrease in absolute humidity inside the cabinet while simultaneously causing slight frost formation on the evaporator, improving heat exchange and reducing system energy consumption.

[0040] After the user loads the load into the display case, closes the door, and powers on, the system starts up. The refrigeration system and the evaporator chamber status monitoring and control system start working simultaneously. The first temperature monitoring element 12, the second temperature monitoring element 13, and the third temperature monitoring element 15 simultaneously monitor the surface temperature of the evaporator 14. The first humidity monitoring element 10 and the second humidity monitoring element 16 monitor the relative humidity of the evaporator chamber in real time. The fourth temperature monitoring element monitors the temperature inside the cabinet in real time. The door opening and closing sensor 7 monitors the opening status of the cabinet door. All the above data are transmitted to the central processing unit 5 in real time. The central processing unit analyzes the data to obtain the absolute humidity data of the evaporator chamber and, in combination with the current temperature inside the cabinet, the surface temperature of the evaporator, and the opening status of the cabinet door, issues commands to the electronic expansion valve 18 and the evaporator fan speed control element 9. The electronic expansion valve 18 maintains a low opening degree, and the evaporator fan maintains the highest fan speed.

[0041] During the stable operation phase of the system, after the user opens the cabinet door for loading or unloading, the door opening sensor detects the door opening, and the fourth temperature monitoring element monitors whether the temperature inside the cabinet fluctuates. If the fluctuation range is ≥2℃, the evaporator fan speed increases to the maximum speed; otherwise, it maintains the original speed. After the door opening sensor detects that the cabinet door is closed, the intermediate processor analyzes the data from the temperature and humidity monitoring element to determine the absolute humidity fluctuation inside the cabinet. If the absolute humidity is higher than 5.01g / m³, the central processor issues an instruction to reduce the opening of the electronic expansion valve, increase the evaporator fan speed (if it was originally at the maximum speed, it remains unchanged), and raise the evaporator surface temperature to (0.5~1℃), causing the humid air inside the cabinet to condense quickly, reducing the absolute humidity of the evaporation chamber. After running for a period of time, once all the condensate has flowed out along the drain pipe, the fan speed decreases, the expansion valve opening increases, the variable frequency compressor power increases, the evaporator surface temperature decreases, and slight frost begins to form.

[0042] The refrigeration system is connected and positioned as follows: the compressor 1 outlet is connected to the condenser 4 inlet; the condenser outlet is connected to the dryer filter 2 inlet; the dryer filter 2 outlet is connected to the electronic expansion valve 18 inlet; the electronic expansion valve 18 outlet is connected to the evaporator 14 inlet; the evaporator outlet 14 is connected to the liquid receiver 11 inlet; and the liquid receiver 11 outlet is connected to the variable frequency compressor 1. The condenser connection pipe is in the water collection pan 17 to accelerate the evaporation of water in the water collection pan 17. The central processing unit 5 is located on top of the cabinet; the door opening / closing sensor 7 is located inside the cabinet door; and the fourth temperature sensor 6 is located at the geometric center of the back of the inner liner of the cabinet. The water guide pipe 19 is connected to the evaporation chamber, allowing the condensate on the evaporator surface to leave the evaporation chamber and enter the water collection pan 17 along the water guide pipe.

[0043] This embodiment also discloses a control method, the control logic of the central processing unit is as follows: Figure 3 As shown, in this embodiment, both the evaporator fan 8 and compressor 1 have four speed settings: high, higher, lower, and low. The central processing unit is set to maintain an optimal absolute humidity range of 5.01 g / m³ inside the cabinet. During the dehumidification stage of the evaporation chamber, the optimal surface temperature of the evaporator 14 is 0.5~1℃. The dehumidification stage time is set according to the absolute humidity inside the cabinet, with the absolute humidity at 44 g / m³... 3 The dehumidification time lasted for 15 minutes, with the absolute humidity remaining between 34 and 44 g / m³. 3 The dehumidification time lasts for 12 minutes, with the absolute humidity at 23~34 g / m³. 3 At that time, the dehumidification time lasted for 9 minutes, and the absolute humidity was between 5.01 and 23 g / m³. 3 At that time, the dehumidification time lasted for 6 minutes, and the relative humidity was less than 5.01 g / m³. 3 The defrosting system does not start.

[0044] When the system is in the start-up phase (the cabinet has just been powered on, and the internal temperature is not yet stable), the door opening / closing monitoring element detects that the cabinet door is open. The evaporator fan 8 and compressor 1 are then turned on to their highest settings, with compressor 1 maintaining high power and the electronic expansion valve 18 maintaining a high opening. After the system detects that the door is closed, the first temperature monitoring element 12, the second temperature monitoring element 13, and the third temperature monitoring element 15 send the evaporator surface temperature data to the central processor 5 in real time. The first humidity monitoring element 12 and the second humidity monitoring element 13 transmit the relative humidity range of the evaporation chamber to the central processor 5. The fourth temperature monitoring element 6 transmits the internal temperature data to the central processor 5. Based on the above data, the absolute humidity of the evaporator surface and the optimal system solution are determined.

[0045] The absolute humidity is 44 g / m³ 3 In the above, the evaporator fan 8 remains at high speed. The compressor 1 switches to low power, the electronic expansion valve 18 switches to low opening, and the opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 15 minutes.

[0046] The absolute humidity is between 34 and 44 g / m³. 3 Evaporator fan 8 remains at high speed. Compressor 1 switches to low power, and electronic expansion valve 18 switches to low opening, adjusting its opening according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, lasting for 12 minutes.

[0047] The absolute humidity is between 23 and 34 g / m³. 3 At this time, the evaporator fan 8 switches to a higher speed. The compressor 1 switches to a lower power, and the electronic expansion valve 18 switches to a lower opening, adjusting the opening according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 9 minutes.

[0048] The absolute humidity is between 5.01 and 23 g / m³. 3 At this time, the evaporator fan 8 switches to a higher speed. The compressor 1 switches to medium power, and the electronic expansion valve 18 switches to a lower opening. The opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin. The dehumidification time lasts for 6 minutes.

[0049] When absolute humidity ≤ 5.01 g / m 3 At this time, the evaporator fan 8 switches to the medium speed, the compressor 1 switches to the highest speed, and the electronic expansion valve maintains the highest opening until the temperature requirement is met.

[0050] After the dehumidification phase ends, the system enters the normal operation phase, and performs optimal matching according to the load and operating conditions.

[0051] After the system starts, the door sensor 7 detects that the cabinet door is closed. The first temperature monitoring element 12, the second temperature monitoring element 13, and the third temperature monitoring element 15 send the evaporator surface temperature data to the central processing unit 5 in real time. The first humidity monitoring element 12 and the second humidity monitoring element 13 transmit the relative humidity range of the evaporation chamber to the central processing unit 5. The fourth temperature monitoring element 6 transmits the cabinet interior temperature data to the central processing unit 5. Based on the above data, the absolute humidity of the evaporator surface and the optimal system solution are determined.

[0052] The absolute humidity is 44 g / m³ 3 Above, evaporator fan 8 switches to high power. Compressor 1 switches to low power, and electronic expansion valve 18 switches to low opening, adjusting its opening according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, lasting for 15 minutes.

[0053] The absolute humidity is between 34 and 44 g / m³. 3 Evaporator fan 8 switches to high power. Compressor 1 switches to low power, and electronic expansion valve 18 switches to low opening. The opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin. The dehumidification time lasts for 12 minutes.

[0054] The absolute humidity is between 23 and 34 g / m³. 3 At this time, the evaporator fan 8 switches to a higher speed. The compressor 1 switches to a lower power, and the electronic expansion valve 18 switches to a lower opening, adjusting the opening according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 9 minutes.

[0055] The absolute humidity is between 5.01 and 23 g / m³. 3 At this time, the evaporator fan 8 switches to a higher speed. The compressor 1 switches to medium power, and the electronic expansion valve 18 switches to a lower opening. The opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin. The dehumidification time lasts for 6 minutes.

[0056] After the dehumidification phase ends, the system enters the normal operation phase, and performs optimal matching according to the load and operating conditions.

[0057] When absolute humidity ≤ 5.01 g / m 3 At this time, the evaporator fan 8 switches to the medium speed, the compressor 1 switches to the highest speed, and the electronic expansion valve maintains the highest opening until the temperature requirement is met.

[0058] When the system is in a stable phase, the user opens the cabinet door. The door opening / closing sensor 7 detects the door opening, and the evaporator fan speed 8 increases. After the cabinet door is closed, the fourth temperature monitoring element 6 detects a temperature fluctuation ≥2℃ inside the cabinet, and the evaporator fan speed 8 increases; if it is at the highest speed, it remains at the highest speed. The first temperature monitoring element 12, the second temperature monitoring element 13, and the third temperature monitoring element 15 send the evaporator surface temperature data to the central processing unit 5 in real time. The first humidity monitoring element 12 and the second humidity monitoring element 13 transmit the relative humidity range of the evaporation chamber to the central processing unit 5. The fourth temperature monitoring element 6 transmits the cabinet temperature data to the central processing unit 5. Based on the above data, the absolute humidity of the evaporator surface and the optimal system solution are obtained.

[0059] The absolute humidity is 44 g / m³ 3 Above, evaporator fan 8 is switched to high power. Compressor 1 is switched to low power, and electronic expansion valve 18 is switched to low opening. The opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin. The dehumidification time lasts for 12 minutes.

[0060] The absolute humidity is between 34 and 44 g / m³. 3 Evaporator fan 8 switches to high power. Compressor 1 switches to low power, and electronic expansion valve 18 switches to low opening. The opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin. The dehumidification time lasts for 9 minutes.

[0061] The absolute humidity is between 23 and 34 g / m³. 3 At this time, the evaporator fan 8 switches to a higher speed. The compressor 1 switches to a lower power, and the electronic expansion valve 18 switches to a lower opening, adjusting the opening according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 6 minutes.

[0062] The absolute humidity is between 5.01 and 23 g / m³. 3 At this time, the evaporator fan 8 switches to a higher speed. The compressor 1 switches to medium power, and the electronic expansion valve 18 switches to a lower opening. The opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin. The dehumidification time lasts for 3 minutes.

[0063] After the dehumidification phase ends, the system enters the normal operation phase, and performs optimal matching according to the load and operating conditions.

[0064] When absolute humidity ≤ 5.01 g / m 3 At this time, the evaporator fan 8 switches to the medium speed, and the status of other components is optimally matched according to the load and operating conditions.

[0065] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its scope and spirit, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A control method for a refrigeration system with evaporator defrosting, characterized in that, Specifically, it includes: The refrigeration system for evaporator defrosting includes a compressor, a condenser, a dryer filter, an evaporator, a water collection tray, and an evaporation fan. The compressor, condenser, dryer filter, and evaporator are connected in sequence. The evaporation fan is installed on the rear side of the evaporator. The connecting pipe of the condenser is located in the water collection tray. The water collection tray is used to collect condensate flowing from the surface of the evaporator. It also includes an electronic expansion valve and an evaporation chamber status monitoring and control module. An electronic expansion valve is installed between the dryer filter and the evaporator. The evaporation chamber status monitoring and control module includes a central processing unit, a fourth temperature monitoring element, a door opening / closing sensor, an evaporator fan speed control element, a first humidity monitoring element, a first temperature monitoring element, a second temperature monitoring element, a third temperature monitoring element, and a second humidity monitoring element. The first, second, and third temperature monitoring elements are mounted on the surface of the evaporator, and the first and second humidity monitoring elements are mounted on the upper sides of the evaporation chamber. The evaporator fan speed control element is used to control the evaporator fan speed. The door opening / closing sensor is used to monitor the opening / closing status of the display cabinet door. The fourth temperature monitoring element is installed in the middle of the evaporation chamber to monitor the temperature of the evaporation chamber. The fourth temperature monitoring element, the door opening / closing sensor, the evaporator fan speed control element, the first humidity monitoring element, the first temperature monitoring element, the second temperature monitoring element, the third temperature monitoring element, the second humidity monitoring element, and the electronic expansion valve are all electrically connected to the central processing unit. The central processing unit collects data from the first temperature monitoring element, the second temperature monitoring element, the third temperature monitoring element, the first humidity monitoring element, the second humidity monitoring element, and the fourth temperature monitoring element, and calculates the absolute humidity of the evaporator surface based on the above data; When the display case door is detected to be open and the system is in the startup phase, after the door opening / closing sensor detects that the door is closed, it is determined whether the absolute humidity in the evaporation chamber is greater than 5.01 g / m³. 3 If it is greater than 5.01 g / m 3 Then, the central processing unit controls the electronic expansion valve to reduce its opening, the compressor power to decrease, and the evaporator surface temperature to drop to 0.5-1℃. The evaporator fan maintains high-speed operation, ensuring that water vapor condenses in the evaporation chamber without forming frost, until the absolute humidity of the evaporation chamber is less than or equal to 5.01 g / m³. 3 When the electronic expansion valve opens higher, the evaporator fan speed decreases. Based on the real-time results from the fourth temperature monitoring element, the central processing unit controls each component to make adjustments, ensuring stable system operation. When the display case door is detected to be open but the system is in a stable phase, the evaporator fan speed increases to create an air curtain, reducing the amount of hot and humid air entering the evaporation chamber. Once the door sensor detects that the door is closed, it is determined whether the absolute humidity in the evaporation chamber exceeds 5.01 g / m³. 3 If it is greater than 5.01 g / m 3 Then, the central processing unit controls the electronic expansion valve to reduce its opening, the compressor power to decrease, and the evaporator surface temperature to drop to 0.5-1℃. The evaporator fan maintains high-speed operation, ensuring that water vapor condenses in the evaporation chamber without forming frost, until the absolute humidity of the evaporation chamber is less than or equal to 5.01 g / m³. 3 When the electronic expansion valve opens higher, the evaporator fan speed decreases. Based on the real-time results from the fourth temperature monitoring element, the central processing unit controls each component to make adjustments, and the system operates stably until the next door opening, repeating the above control process.

2. The control method for an evaporator defrosting refrigeration system according to claim 1, characterized in that, The surface of the evaporator is coated with a hydrophobic coating.

3. The control method for an evaporator defrosting refrigeration system according to claim 1, characterized in that, A liquid storage pipe is provided between the evaporator and the compressor. The liquid storage pipe is used to adapt to the changes in the liquid supply demand caused by the load variation of the evaporator.

4. The control method for an evaporator defrosting refrigeration system according to claim 1, characterized in that, When the system is in the start-up phase, the door opening / closing monitoring element detects that the cabinet door is open. The specific control process is as follows: the evaporator fan is turned on to its highest speed, the compressor maintains a high power, and the electronic expansion valve maintains a high opening. After the system detects that the door is closed, the central processing unit collects data from the first temperature monitoring element, the second temperature monitoring element, the third temperature monitoring element, the first humidity monitoring element, the second humidity monitoring element, and the fourth temperature monitoring element. Based on the above data, the absolute humidity of the evaporator surface and the optimal solution of the system are obtained. The absolute humidity is 44 g / m³ 3 In the above, the evaporator fan is kept at a high speed, the compressor is switched to low power, the electronic expansion valve is switched to a low opening, and the opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 15 minutes. The absolute humidity is between 34 and 44 g / m³. 3 The evaporator fan is kept at high speed, the compressor is switched to low power, the electronic expansion valve is switched to low opening, and the opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 12 minutes. The absolute humidity is between 23 and 34 g / m³. 3 At this time, the evaporator fan switches to a higher speed, the compressor switches to a lower power, the electronic expansion valve switches to a lower opening, and the opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 9 minutes. The absolute humidity is between 5.01 and 23 g / m³. 3 At this time, the evaporator fan switches to a higher speed, the compressor switches to medium power, the electronic expansion valve switches to a lower opening, and the opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 6 minutes. Absolute humidity ≤ 5.01 g / m³ 3 At this time, the evaporator fan switches to medium speed, the compressor switches to the highest speed, and the electronic expansion valve maintains the highest opening until the temperature requirement is met.

5. The control method for an evaporator defrosting refrigeration system according to claim 1, characterized in that, When the system is in a stable phase, the door opening / closing sensor detects that the cabinet door is open, and the evaporator fan speed increases. After the cabinet door is closed, the fourth temperature monitoring element detects that the internal temperature fluctuation is ≥2℃, and the evaporator fan switches to its highest speed. The central processing unit collects data from the first, second, third, first, second, and fourth temperature monitoring elements, and calculates the absolute humidity of the evaporator surface and the optimal system solution based on the above data. The absolute humidity is 44 g / m³ 3 In the above steps, the evaporator fan switches to high speed, the compressor switches to low power, the electronic expansion valve switches to low opening, and the opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 12 minutes. The absolute humidity is between 34 and 44 g / m³. 3 The evaporator fan switches to high speed, the compressor switches to low power, the electronic expansion valve switches to low opening, and the opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 9 minutes. The absolute humidity is between 23 and 34 g / m³. 3 At this time, the evaporator fan switches to a higher speed, the compressor switches to a lower power, the electronic expansion valve switches to a lower opening, and the opening is adjusted according to the evaporator surface temperature until the evaporator surface temperature reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 6 minutes. The absolute humidity is between 5.01 and 23 g / m³. 3 At this time, the evaporator fan switches to a higher speed, the compressor switches to medium power, the electronic expansion valve switches to a lower opening, and the opening is adjusted according to the surface temperature of the evaporator until the surface temperature of the evaporator reaches 0.5~1℃, at which point condensation and dehumidification begin, and the dehumidification time lasts for 3 minutes. When absolute humidity ≤ 5.01 g / m 3 At this time, the evaporator fan switches to the medium speed, while the status of other components remains unchanged.

6. A display cabinet, characterized in that, A control method for a refrigeration system with evaporator defrosting as described in any one of claims 1-5.

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