An ice-making system, an ice-making control method, and an ice-making device.

Abstract

This invention discloses an ice-making system, an ice-making control method, and an ice-making device. The system includes a refrigerator refrigeration circuit, a water storage box, an ice-making mold, a shell-and-tube subcooler, a water-side delivery assembly, a second electronic expansion valve, a temperature detection assembly, a gas-liquid separator, and a controller. The shell-and-tube subcooler is located between the water storage box and the ice-making mold. The inner tube supplies ice-making water, and the outer tube forms a refrigerant flow channel with the inner tube, allowing the ice-making water and refrigerant to exchange heat in a counter-current manner. The controller adjusts the water supply status and the opening of the second electronic expansion valve according to the water outlet temperature and the refrigerant outlet temperature, causing the ice-making water to form subcooled water and nucleate within the ice-making mold. This solution can improve ice-making efficiency and reduce the risk of premature freezing and liquid slugging.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment and automatic ice-making technology, and in particular to an ice-making system, an ice-making control method, and an ice-making device. Background Technology

[0002] Refrigerators, freezers, and other refrigeration equipment typically include automatic ice-making devices. Most existing ice-making devices use a direct cooling method, where water from a storage tank is poured into an ice mold, and then the water is cooled by the low-temperature environment of the freezer compartment or a heat exchange component corresponding to the ice-making area, causing the water to gradually freeze into ice. This method is relatively simple in structure and easy to arrange, but the ice-making process requires first cooling the water to near 0°C before completing the phase change from liquid to solid. Both sensible heat cooling and latent heat release are time-consuming, resulting in a long ice-making cycle and low ice production efficiency. Furthermore, as the water gradually freezes in the ice mold, the nucleation location and time are difficult to control stably, leading to problems such as air bubbles, turbidity, or uneven structure within the ice.

[0003] To improve ice-making speed, existing technologies have proposed subcooled water ice-making methods. These methods typically involve first cooling water to below 0°C using a heat exchanger and maintaining it in a subcooled liquid state. Then, the subcooling state is relieved through methods such as crystallization, disturbance, or contact nucleation, allowing the subcooled water to freeze rapidly. Compared to traditional direct cooling ice-making methods, subcooled water ice-making can shorten the phase change waiting time and, to some extent, increase the ice-making speed.

[0004] However, existing subcooled water ice-making solutions still have the following shortcomings: First, some subcooled water ice-making equipment requires independent refrigeration circuits, dedicated compressors, or independent heat exchange modules, resulting in complex overall structures, large space requirements, and high manufacturing costs, making it difficult to directly integrate into space-constrained refrigeration equipment such as household refrigerators. Second, subcooled water is in a metastable state. During the process of transporting it from the heat exchanger to the ice-making mold, it is prone to premature nucleation due to factors such as rough inner walls of the transport pipeline, sharp bends, abrupt changes in cross-section, vibration, or impurities, leading to pipe freezing, heat exchanger blockage, or unstable water supply. Third, if control is based solely on a fixed-flow water pump or a fixed-opening throttle valve, it is difficult to adapt to changes in inlet water temperature, refrigerant state, freezer load, and ice-making demand, easily leading to problems of insufficient or excessive subcooling; insufficient subcooling makes it difficult to form ice quickly, while excessive subcooling easily causes premature freezing during transport. Fourth, when the subcooling heat exchange unit is connected to the refrigerator's original refrigeration circuit, it is also necessary to take into account the basic refrigeration needs of the freezer compartment, the stability of refrigerant distribution, and the safety of compressor return gas. Otherwise, it may affect the overall refrigeration performance and even increase the risk of compressor liquid slugging. Summary of the Invention

[0005] To address the problems in existing technologies where ice-making water is difficult to be stably cooled and transported into subcooled water suitable for nucleation and ice making under the constraints of the refrigerator's original refrigeration circuit, and is prone to premature nucleation and pipe freezing during transportation, while also needing to consider the stability of refrigerant distribution and the safety of compressor return gas, one objective of this invention is to provide an ice-making system. To achieve the above objectives, the present invention adopts the following technical solution: an ice-making system, comprising a refrigerator refrigeration circuit, a water storage box, an ice-making mold, a sleeve-type subcooler, a water-side conveying assembly, a second electronic expansion valve, a temperature detection assembly, a gas-liquid separator, and a controller; The refrigerator refrigeration circuit includes a compressor, a condenser, a dryer filter, a first throttling element, and an evaporator connected in sequence. A branch point is provided between the outlet of the dryer filter and the first throttling element, and the outlet of the evaporator is connected to the suction side of the compressor. The sleeve-type subcooler is located between the water storage box and the ice-making mold, and includes an inner tube and an outer tube sleeved on the outside of the inner tube. The inner tube forms a water flow channel, and a refrigerant flow channel is formed between the inner tube and the outer tube. The water-side conveying assembly includes an inlet valve and a water pump, and connects the water storage box and the water inlet of the inner pipe. The water outlet of the inner pipe is connected to the ice-making mold via a subcooled water conveying pipe. The refrigerant inlet of the refrigerant flow channel is connected to the branch point via the second electronic expansion valve, and the refrigerant outlet of the refrigerant flow channel is connected to the return gas side of the compressor via the gas-liquid separator; The water inlet and the refrigerant outlet are located at the first end of the shell-and-tube subcooler, and the water outlet and the refrigerant inlet are located at the second end of the shell-and-tube subcooler; The temperature detection component includes a first temperature detection element for detecting the water temperature at the water outlet and a second temperature detection element for detecting the refrigerant temperature at the refrigerant outlet. The controller is electrically connected to the water-side delivery assembly, the second electronic expansion valve, the first temperature sensor, and the second temperature sensor, and is configured to adjust the water supply status and the opening degree of the second electronic expansion valve according to the water temperature and the refrigerant temperature. The water inlet area of ​​the ice-making mold is equipped with a nucleation trigger.

[0006] Furthermore, the shell-and-tube subcooler includes a first end flow collection structure and a second end flow collection structure, with the water inlet and the refrigerant outlet located in the first end flow collection structure, and the water outlet and the refrigerant inlet located in the second end flow collection structure; The water inlet is connected to one end of the inner pipe, the water outlet is connected to the other end of the inner pipe, and the refrigerant inlet and the refrigerant outlet are respectively connected to both ends of the refrigerant flow channel.

[0007] Furthermore, the inner tube and the outer tube are coaxially arranged, and a plurality of support rings are axially spaced between the inner tube and the outer tube. The support rings are connected to the inner tube and / or the outer tube to define the annular cross-section of the refrigerant flow channel.

[0008] Furthermore, the inner tube is connected to the first end flow collecting structure and / or the second end flow collecting structure via a compression fitting, and an elastic sealing ring is provided at the compression fitting. An expansion compensation section is provided near at least one end of the outer tube. The expansion compensation section is a corrugated compensation section, a U-shaped compensation section, or a thin-walled bending section.

[0009] Furthermore, the subcooled water delivery pipe includes a low-disturbance pipe section extending from the water outlet to the ice-making mold. The inner wall roughness of the low-disturbance pipe section is less than or equal to 0.4 μm, and a smooth transition structure is provided at the connection between the low-disturbance pipe section and the ice-making mold.

[0010] Furthermore, the low-disturbance pipe section is a 316L stainless steel pipe, a PFA pipe, or an FEP pipe, the inner diameter of the low-disturbance pipe section is 2.0mm to 4.0mm, the bending radius of the low-disturbance pipe section is not less than 3 times its outer diameter, and an insulation layer is provided on the outside of the low-disturbance pipe section.

[0011] Furthermore, the nucleation triggering part includes at least one of piezoelectric ceramic sheet, roughened surface, micro-protrusion, micro-groove or turbulence structure; When the nucleation triggering part includes a piezoelectric ceramic sheet, the piezoelectric ceramic sheet is fixed to the bottom or side wall of the ice-making mold and connected to the controller via a wire.

[0012] Furthermore, the piezoelectric ceramic sheet has a thickness of 0.2 mm to 0.5 mm, a vibration frequency of 20 kHz to 40 kHz, and an amplitude of 1 μm to 10 μm, and the piezoelectric ceramic sheet is fixed to the ice-making mold by thermally conductive adhesive.

[0013] Furthermore, the gas-liquid separator includes an inlet, a gas phase outlet, and a liquid phase outlet. The inlet is connected to the refrigerant outlet, the gas phase outlet is connected to the suction side of the compressor via a first one-way valve, and the liquid phase outlet is connected to the crankcase of the compressor or a suction pipe section near the crankcase via a second one-way valve.

[0014] Furthermore, a pressure sensor is installed on the pipeline between the outlet of the dryer filter and the branch point, and the pressure sensor is connected to the controller; The controller determines the initial opening or maximum permissible opening of the second electronic expansion valve based on the pressure value of the pressure sensor.

[0015] Furthermore, a vent valve is provided at the lower position of the shell-and-tube subcooler, and the vent valve is electrically connected to the controller; The inlet of the vent valve is connected to the inner pipe, and the outlet of the vent valve is connected to a water receiving pan or a drain pipe.

[0016] To address the shortcomings of existing technologies, another objective of this invention is to provide an ice-making control method. By adjusting the water supply status and the opening of the second electronic expansion valve according to the water temperature at the water outlet and the refrigerant temperature at the refrigerant outlet during the ice-making process, the ice-making water is kept in a subcooled state suitable for nucleation before entering the ice-making mold, thereby reducing the risks of premature nucleation during transport, pipeline freezing, and abnormal compressor return gas.

[0017] To achieve the above objectives, the present invention adopts the following technical solution: an ice-making control method, using the above-mentioned ice-making system, and operating according to the following steps: In response to the ice-making command, the second electronic expansion valve is opened, allowing the refrigerant in the refrigerator's refrigeration circuit to enter the refrigerant flow channel through the branch point; During the pre-cooling stage, the water-side delivery assembly stops supplying water, and the second electronic expansion valve maintains a preset pre-cooling opening. After precooling is completed, the water-side delivery assembly is controlled to send the ice-making water in the water storage box into the inner tube, and the flow direction of the ice-making water in the inner tube is opposite to the flow direction of the refrigerant in the refrigerant channel. The water outlet temperature detected by the first temperature sensor and the refrigerant outlet temperature detected by the second temperature sensor are obtained. Adjust the water supply status of the water-side delivery assembly and the opening degree of the second electronic expansion valve according to the water temperature and the refrigerant temperature; The subcooled water, after being treated by the shell-and-tube subcooler, is sent into the ice-making mold through the subcooled water delivery pipe, and the nucleation triggering part triggers the nucleation of the subcooled water.

[0018] Furthermore, during the steady-state subcooling stage, adjusting the water supply status of the water-side conveying assembly and the opening degree of the second electronic expansion valve according to the water outlet temperature includes: When the water temperature is higher than the upper limit of the target subcooling temperature range, the opening of the second electronic expansion valve is increased first. When the opening of the second electronic expansion valve reaches its upper limit and the water temperature is still higher than the upper limit of the target subcooling temperature range, the water supply flow rate of the water-side delivery component is reduced. When the water temperature is lower than the lower limit of the target subcooling temperature range, reduce the opening of the second electronic expansion valve or increase the water supply flow rate of the water-side delivery assembly.

[0019] Furthermore, protection control is implemented based on the refrigerant temperature at the refrigerant outlet and the water temperature at the water outlet, including: When the refrigerant temperature is lower than the first refrigerant temperature threshold, the opening of the second electronic expansion valve is reduced; When the refrigerant temperature is lower than the second refrigerant temperature threshold, the second electronic expansion valve is closed and the water-side delivery assembly is stopped; Wherein, the second refrigerant temperature threshold is lower than the first refrigerant temperature threshold; When the water temperature is lower than the water temperature protection threshold, the opening of the second electronic expansion valve is reduced, and the water supply flow of the water-side delivery assembly is maintained or increased.

[0020] Furthermore, the ice-making system includes a vent valve located at the low position of the shell-and-tube subcooler, the inlet of which is connected to the inner tube, and the outlet of which is connected to a water receiving pan or a drain pipe. After ice making is completed, the second electronic expansion valve is closed, the water-side delivery assembly is stopped supplying water, and the drain valve is opened for a preset time to drain the residual water in the inner pipe and / or the subcooled water delivery pipe.

[0021] The present invention also provides an ice-making device, including a housing and the ice-making system described above disposed within the housing.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. By drawing a refrigerant branch from the original refrigeration circuit of the refrigerator and using a coaxial subcooler to perform reverse heat exchange on the ice-making water, the ice-making water can be treated into subcooled water suitable for nucleation and ice making without setting up an independent compressor or independent refrigeration circuit. At the same time, by adjusting the water supply status and the opening of the second electronic expansion valve through dual parameters of water temperature and refrigerant temperature, and combined with the gas-liquid separator and nucleation trigger, the system can take into account stable output of subcooled water, nucleation in the mold, and safe return gas from the compressor.

[0023] 2. By arranging the water inlet, refrigerant outlet, water outlet, and refrigerant inlet through the first end collection structure and the second end collection structure respectively, the inlet and outlet connection relationship between the inner pipe water flow channel and the outer refrigerant flow channel is clearer, which facilitates the formation of a stable counter-flow heat exchange path and improves the assembly reliability and flow channel connectivity stability of the shell-and-tube subcooler.

[0024] 3. By setting the inner and outer tubes coaxially and placing multiple support rings between them, the annular cross-section of the refrigerant flow channel can be defined, reducing the uneven refrigerant flow caused by the eccentricity of the inner tube, and allowing the refrigerant to flow more evenly along the outer side of the inner tube, thereby improving heat exchange stability.

[0025] 4. Connecting the inner pipe to the end manifold structure using a compression fitting and an elastic sealing ring helps improve the sealing performance of the water connection. By setting an expansion compensation section at the end of the outer pipe, thermal expansion and contraction caused by alternating hot and cold temperatures can be buffered, reducing stress concentration and leakage risks at the connection.

[0026] 5. By setting a low-disturbance pipe section in the subcooled water delivery pipe and limiting its inner wall roughness to less than or equal to 0.4μm, and setting a smooth transition structure at the connection with the ice-making mold, frictional disturbance, abrupt changes in cross section and local eddies during the subcooled water delivery process can be reduced, thereby reducing the risk of pre-nucleation of subcooled water or freezing of the pipeline before it enters the ice-making mold.

[0027] 6. By limiting the material, inner diameter, bending radius, and insulation layer structure of the low-disturbance pipe section, the smoothness of the inner wall of the pipeline and the stability of the transport can be further improved, reducing the impact of impurity precipitation, sharp bend disturbance, and external temperature fluctuations on the state of the subcooled water, so that the subcooled water can be transported to the ice-making mold more stably.

[0028] 7. By setting the nucleation triggering part as at least one of piezoelectric ceramic sheet, roughened surface, micro-protrusion, micro-groove or turbulence structure, a clear nucleation triggering condition can be provided after the supercooled water enters the ice-making mold, so that the supercooled water nucleates in the ice-making mold instead of nucleating in advance in the delivery pipeline; wherein, after the piezoelectric ceramic sheet is connected to the controller, active nucleation triggering can also be realized.

[0029] 8. By limiting the thickness, vibration frequency, amplitude, and fixing method of the piezoelectric ceramic sheet, the piezoelectric ceramic sheet can generate stable high-frequency micro-amplitude vibration when supercooled water enters the ice-making mold, thereby improving the controllability and repeatability of nucleation triggering and reducing the quality fluctuation of ice blocks caused by random nucleation.

[0030] 9. By setting up a gas-liquid separator with gas phase outlet and liquid phase outlet, and allowing the gas phase refrigerant and liquid phase refrigerant to return to the compressor side through one-way valves respectively, the risk of liquid refrigerant directly entering the compressor suction side can be reduced, and refrigerant backflow can be reduced, which is beneficial to improving the reliability of compressor operation.

[0031] 10. By installing a pressure sensor between the outlet of the dryer filter and the branch point, and determining the initial opening or maximum allowable opening of the second electronic expansion valve based on the pressure value, the opening and regulation of the refrigerant branch can be matched with the actual pressure state of the refrigerator refrigeration circuit, reducing the impact of abnormal refrigerant distribution, insufficient refrigerant supply, or abnormal system load on the ice-making process.

[0032] 11. By installing a drain valve at the low position of the shell-and-tube subcooler and connecting the drain valve to the inner tube, residual water in the inner tube and subcooled water delivery pipe can be drained after ice making is completed, reducing the risk of residual water freezing and clogging the flow channel during shutdown and improving the reliability of the next ice making start-up.

[0033] 12. By setting steps such as precooling, water inlet, countercurrent heat exchange, dual temperature detection, flow regulation, and mold nucleation in the ice-making control method, the ice-making water can reach a suitable subcooled state for nucleation before entering the ice-making mold, and be triggered to nucleate in the ice-making mold. This achieves stable production of subcooled water and rapid ice making from the control process.

[0034] 13. By prioritizing the adjustment of the opening of the second electronic expansion valve based on the water outlet temperature during the steady-state subcooling stage, and then adjusting the water supply flow rate after the valve adjustment reaches the upper limit, a graded adjustment logic with refrigerant side priority and water side assistance can be formed, making it easier to maintain the subcooled water temperature within the target subcooling temperature range and reducing insufficient or excessive subcooling.

[0035] 14. By implementing protective control based on the refrigerant outlet temperature and the water outlet temperature, the second electronic expansion valve can be reduced or closed when the refrigerant temperature is abnormally low, and the refrigerant opening and water supply flow can be adjusted when the water temperature is below the water temperature protection threshold, thereby reducing the risk of compressor liquid slugging and water circuit freezing, and improving system safety.

[0036] 15. By closing the second electronic expansion valve, stopping the water supply, and opening the drain valve after ice making is completed, residual water in the inner pipe and / or subcooled water delivery pipe can be discharged in a timely manner, preventing residual water from freezing and causing blockage in the low temperature environment, while keeping the system in a good state of restartability in standby mode.

[0037] 16. By integrating the above-mentioned ice-making system into the ice-making device, the subcooling treatment of ice-making water and controlled nucleation ice-making can be realized within the device itself, thereby improving the integration level, ice-making efficiency and operational reliability of the ice-making device. Attached Figure Description

[0038] Figure 1 This is a three-dimensional structural diagram of a shell-and-tube subcooler provided in an embodiment of the present invention; Figure 2 This is a schematic cross-sectional view of a shell-and-tube subcooler provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the overall structure of an ice-making system provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the ice-making mold and the nucleation triggering part provided in an embodiment of the present invention; Figure 5 This is a flowchart of an ice-making control method provided in an embodiment of the present invention.

[0039] In the diagram: 1. Shell-and-tube subcooler; 101. Outer tube; 102. Inner tube; 103. Refrigerant inlet; 104. Refrigerant outlet; 105. Water outlet; 106. Water inlet; 2. Water storage box; 3. Water inlet valve; 4. Water pump; 5. First temperature sensor; 6. Second temperature sensor; 7. Solenoid valve; 8. Water receiving component; 9. Ice mold; 10. Evaporator; 11. First expansion valve; 12. Second expansion valve; 13. Pressure sensor; 14. Dryer filter; 15. Condenser; 16. Compressor; 17. First check valve; 18. Second check valve; 19. Gas-liquid separator; 20. Controller; 21. Wire; 22. Piezoelectric ceramic plate. Detailed Implementation

[0040] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Where there is no conflict, the technical features of the various embodiments can be combined with each other.

[0041] In this embodiment, the first expansion valve 11 can be a specific form of the first throttling element, the second expansion valve 12 can be a specific form of the second electronic expansion valve, the solenoid valve 7 can be a specific form of the drain valve, and the water receiving component 8 can be a water receiving tray or a drain pipe. For the first end flow collecting structure, the second end flow collecting structure, the support ring, the compression fitting, the elastic sealing ring, the expansion compensation section, the subcooled water conveying pipe, the low-disturbance pipe section, the smooth transition structure, and the insulation layer, which are not separately numbered in the drawings but are described in the claims, they will be described by name below, and no further reference numerals will be used in the drawings.

[0042] Example 1 Reference Figures 1 to 4 This is the first embodiment of the present invention. This embodiment provides an ice-making system that can pre-treat the ice-making water in the water storage box 2 into stable subcooled water before it enters the ice-making mold 9, and achieve controlled nucleation in the ice-making mold 9. The system includes: a shell-and-tube subcooler 1, a water storage box 2, a water inlet valve 3, a water pump 4, a first temperature sensor 5, a second temperature sensor 6, a solenoid valve 7, a water receiving component 8, an ice-making mold 9, an evaporator 10, a first expansion valve 11, a second expansion valve 12, a pressure sensor 13, a dryer filter 14, a condenser 15, a compressor 16, a first one-way valve 17, a second one-way valve 18, a gas-liquid separator 19, a controller 20, a wire 21, and a piezoelectric ceramic plate 22.

[0043] Specifically, a shell-and-tube subcooler 1 is installed between the water storage box 2 and the ice-making mold 9. By installing the shell-and-tube subcooler 1, the ice-making water can exchange heat with the refrigerant before entering the ice-making mold 9, thus reducing the ice-making water to a subcooled state suitable for nucleation and ice making. The shell-and-tube subcooler 1 includes an outer tube 101 and an inner tube 102. The outer tube 101 is sleeved outside the inner tube 102, which is used to supply the ice-making water flow and forms a water flow channel. A refrigerant flow channel is formed between the outer tube 101 and the inner tube 102. By setting the outer tube 101 and the inner tube 102, the ice-making water and the refrigerant can exchange heat in mutually isolated flow channels, avoiding direct contact between the ice-making water and the refrigerant, and at the same time facilitating the formation of a longer heat exchange path.

[0044] Furthermore, one end of the inner tube 102 is connected to the water inlet 106, and the other end is connected to the water outlet 105. The water storage box 2 is connected to the water inlet 106 through the water inlet valve 3 and the water pump 4, and the water outlet 105 is connected to the ice-making mold 9 through the subcooled water delivery pipe. By setting the water inlet valve 3, it is convenient to control the water supply from the water storage box 2 to the shell-and-tube subcooler 1; by setting the water pump 4, it is convenient to drive the ice-making water into the inner tube 102 and flow along the inner tube 102; by setting the water outlet 105 and the subcooled water delivery pipe, it is convenient to deliver the heat-exchanged subcooled water to the ice-making mold 9.

[0045] The refrigerant flow path between the outer pipe 101 and the inner pipe 102 is connected to the refrigerant inlet 103 and the refrigerant outlet 104, respectively. The refrigerant inlet 103 is connected to the branch position between the outlet of the dryer filter 14 and the first expansion valve 11 via the second expansion valve 12, and the refrigerant outlet 104 is connected to the gas-liquid separator 19. By setting the refrigerant inlet 103 and the refrigerant outlet 104, it is convenient for the refrigerant to enter the shell-and-tube subcooler 1 and exchange heat with the ice-making water in the inner pipe 102; by setting the second expansion valve 12, it is convenient to control the refrigerant flow rate entering the shell-and-tube subcooler 1.

[0046] Preferably, the water inlet 106 and refrigerant outlet 104 are located at one end of the shell-and-tube subcooler 1, and the water outlet 105 and refrigerant inlet 103 are located at the other end. Thus, the ice-making water enters the inner tube 102 through the water inlet 106 and flows to the water outlet 105, while the refrigerant enters the refrigerant flow channel between the outer tube 101 and the inner tube 102 through the refrigerant inlet 103 and flows to the refrigerant outlet 104, creating a counter-current flow between the ice-making water and the refrigerant in the shell-and-tube subcooler 1. This counter-current flow increases the average heat exchange temperature difference of the ice-making water along the flow direction, allowing the ice-making water to reach a subcooled state within a shorter heat exchange path.

[0047] Furthermore, the first temperature sensor 5 is located at or near the water outlet 105 to detect the water temperature output by the shell-and-tube subcooler 1; the second temperature sensor 6 is located at or near the refrigerant outlet 104 to detect the refrigerant temperature at the refrigerant outlet 104. Both the first temperature sensor 5 and the second temperature sensor 6 are connected to the controller 20. The first temperature sensor 5 facilitates determining whether the ice-making water has reached the target subcooling temperature; the second temperature sensor 6 facilitates determining the refrigerant heat exchange status and the safe return gas status; and the controller 20 facilitates adjusting the inlet valve 3, the water pump 4, and the second expansion valve 12 according to the water temperature and the refrigerant temperature.

[0048] The ice-making mold 9 is used to receive the subcooled water treated by the sleeve-type subcooler 1. A piezoelectric ceramic plate 22 is installed on the ice-making mold 9, and the piezoelectric ceramic plate 22 is connected to the controller 20 via a wire 21. By installing the piezoelectric ceramic plate 22, high-frequency micro-amplitude vibrations are easily generated after the subcooled water enters the ice-making mold 9. This causes the subcooled water entering the ice-making mold 9 to preferentially undergo local nucleation near the piezoelectric ceramic plate 22, and the nucleation process extends to the surrounding water body, thereby improving the stability and repeatability of nucleation triggering.

[0049] Working Principle: At the start of ice making, controller 20 opens the second expansion valve 12, allowing refrigerant to enter the shell-and-tube subcooler 1 through refrigerant inlet 103. Subsequently, controller 20 controls the inlet valve 3 and water pump 4 to operate, causing the ice-making water in the water storage box 2 to enter the inner tube 102 through water inlet 106. The ice-making water flows in the inner tube 102, while the refrigerant flows in reverse between the outer tube 101 and the inner tube 102, resulting in counter-current heat exchange. The first temperature sensor 5 detects the water temperature at the water outlet 105, and the second temperature sensor 6 detects the refrigerant temperature at the refrigerant outlet 104. Based on the detection results, controller 20 adjusts water pump 4, inlet valve 3, and the second expansion valve 12 to maintain the ice-making water output from water outlet 105 in a suitable subcooled state for ice making. After the subcooled water enters the ice mold 9, controller 20 drives the piezoelectric ceramic plate 22 via wire 21, causing the subcooled water to nucleate and freeze within the ice mold 9.

[0050] In summary, by using the coaxial subcooler 1, water storage box 2, water inlet valve 3, water pump 4, first temperature detection element 5, second temperature detection element 6, ice-making mold 9, second expansion valve 12 and controller 20 together, the refrigerant in the refrigerator's refrigeration circuit can be used to subcool the ice-making water without setting up an independent refrigeration circuit. This solves the problems of long ice-making cycle, unstable subcooled water state and easy nucleation of subcooled water during transportation in the existing ice-making method.

[0051] Example 2 Reference Figure 1 and Figure 2This is the second embodiment of the present invention. Unlike the previous embodiment, this embodiment further provides a specific structure of the shell-and-tube subcooler 1, which solves the problems of unclear internal heat exchange path, unclear flow direction of ice-making water and refrigerant, and insufficient heat exchange stability of the shell-and-tube subcooler 1.

[0052] Specifically, the shell-and-tube subcooler 1 includes an outer tube 101 and an inner tube 102. The inner tube 102 is disposed inside the outer tube 101, and the inner tube 102 and the outer tube 101 are coaxially arranged. By setting the outer tube 101 and the inner tube 102 coaxially, the refrigerant can flow more evenly along the outer side of the inner tube 102, thereby reducing the problems of insufficient local heat exchange or excessive local subcooling.

[0053] Furthermore, the refrigerant inlet 103 is located near the water outlet 105, and the refrigerant outlet 104 is located near the water inlet 106. The water inlet 106 is located near the refrigerant outlet 104, and the water outlet 105 is located near the refrigerant inlet 103. This positional relationship ensures that the flow direction of the ice-making water is opposite to that of the refrigerant, forming counter-current heat exchange. Counter-current heat exchange allows the ice-making water to still exchange heat sufficiently with the low-temperature refrigerant near the water outlet 105, facilitating the ice-making water to reach the target subcooled state.

[0054] The shell-and-tube subcooler 1 includes a first end collector structure and a second end collector structure. A water inlet 106 and a refrigerant outlet 104 are located in the first end collector structure, while a water outlet 105 and a refrigerant inlet 103 are located in the second end collector structure. The water inlet 106 is connected to one end of the inner tube 102, and the water outlet 105 is connected to the other end of the inner tube 102. The refrigerant inlet 103 and the refrigerant outlet 104 are respectively connected to the two ends of the refrigerant flow channel between the outer tube 101 and the inner tube 102. By setting up the first and second end collector structures, the water and refrigerant flow channels can be stably distributed and collected at both ends of the shell-and-tube subcooler 1, reducing problems such as unclear flow channel connections or leakage at the connections.

[0055] Preferably, a support ring is provided axially between the inner tube 102 and the outer tube 101. The support ring is connected to the inner tube 102 and / or the outer tube 101 to limit the radial distance between the inner tube 102 and the outer tube 101. By providing the support ring, the eccentricity of the inner tube 102 relative to the outer tube 101 can be reduced, so that a stable annular refrigerant flow channel is formed between the outer tube 101 and the inner tube 102, thereby improving the uniformity of refrigerant flow and the stability of heat transfer.

[0056] Furthermore, the inner tube 102 is connected to the first end manifold structure and / or the second end manifold structure via a compression fitting, with an elastic sealing ring at the fitting. The compression fitting facilitates the assembly and connection between the inner tube 102 and the end manifold structure; the elastic sealing ring improves the sealing performance at the connection, reducing the risk of ice-making water or refrigerant leakage. An expansion compensation section is provided near at least one end of the outer tube 101. This expansion compensation section can be a corrugated section, a U-shaped section, or a thin-walled bent section. The expansion compensation section buffers the difference in thermal expansion and contraction between the outer tube 101 and the inner tube 102 caused by alternating hot and cold temperatures, reducing stress concentration at the end connection.

[0057] Working principle: When the second expansion valve 12 opens, refrigerant enters the shell-and-tube subcooler 1 through the refrigerant inlet 103; when the water pump 4 starts, ice-making water enters the inner tube 102 through the water inlet 106. Since the water inlet 106 and the refrigerant outlet 104 are on the same side, and the water outlet 105 and the refrigerant inlet 103 are on the same side, the ice-making water and the refrigerant flow in opposite directions within the shell-and-tube subcooler 1. The support ring keeps the refrigerant flow path between the inner tube 102 and the outer tube 101 stable, the compression fitting and the elastic sealing ring ensure reliable end connection, and the expansion compensation section buffers thermal deformation, allowing the shell-and-tube subcooler 1 to maintain stable heat exchange during the reverse ice-making process.

[0058] In summary, by setting up an outer pipe 101, an inner pipe 102, a refrigerant inlet 103, a refrigerant outlet 104, a water outlet 105, a water inlet 106, a first end collection structure, a second end collection structure, a support ring, a compression fitting, an elastic sealing ring, and an expansion compensation section, the water path and refrigerant path of the shell-and-tube subcooler 1 can be clearly defined, improving assembly reliability and heat exchange stability, and solving the problems of unclear heat exchange direction, insufficient end connection stability, and unstable subcooled water output.

[0059] Example 3 Reference Figure 3 This is the third embodiment of the present invention. Unlike the previous embodiment, this embodiment further provides a refrigerant distribution and pressure protection structure after the shell-and-tube subcooler 1 is connected to the original refrigeration circuit of the refrigerator. This solves the problem that the connection of the refrigerant branch may affect the stability of the liquid supply to the evaporator 10 and the safe operation of the compressor 16.

[0060] Specifically, the refrigerator's refrigeration circuit includes a compressor 16, a condenser 15, a dryer filter 14, a first expansion valve 11, and an evaporator 10. The compressor 16, condenser 15, dryer filter 14, first expansion valve 11, and evaporator 10 are connected sequentially. The compressor 16 facilitates refrigerant circulation; the condenser 15 facilitates the condensation of the high-temperature, high-pressure refrigerant; the dryer filter 14 facilitates the drying and filtering of the refrigerant; the first expansion valve 11 facilitates the control of the refrigerant state entering the evaporator 10; and the evaporator 10 facilitates the provision of cooling capacity for the refrigerator's basic cooling function.

[0061] Furthermore, the second expansion valve 12 is connected at the branch position between the outlet of the dryer filter 14 and the first expansion valve 11, and the outlet of the second expansion valve 12 is connected to the refrigerant inlet 103 of the shell-and-tube subcooler 1. By setting the second expansion valve 12, a portion of the refrigerant can be drawn from the refrigerator refrigeration circuit into the shell-and-tube subcooler 1, thereby achieving ice-making water subcooling without the need for a separate compressor or independent refrigeration circuit.

[0062] The pressure sensor 13 is installed on the pipeline between the outlet of the dryer filter 14 and the first expansion valve 11, and is connected to the controller 20. By installing the pressure sensor 13, the controller 20 can determine the initial opening or maximum allowable opening of the second expansion valve 12 based on the pressure value at that location, so that the opening state of the refrigerant branch of the coaxial subcooler 1 matches the actual pressure state of the refrigerator refrigeration circuit.

[0063] Preferably, the controller 20 executes the following control strategy based on the pressure value of the pressure sensor 13: When the pressure is within the normal range, the controller 20 consults a preset "pressure-optimal opening mapping table" to determine the initial opening of the second expansion valve 12 corresponding to the current pressure value, reducing the response lag caused by the slow adjustment of the second expansion valve 12 from the closed state; when the pressure is below the first threshold, for example, below 0.8 MPa when using R600a refrigerant or below 1.0 MPa when using R134a refrigerant, the controller 20 determines that there is a refrigerant leak or circulation obstruction in the system, forcibly closes the second expansion valve 12 and stops the ice-making program to prevent the compressor 16 from being damaged due to poor lubrication or low suction pressure; when the pressure is above the second threshold, for example, above 2.5 MPa when using R600a refrigerant, the controller 20 determines that the heat dissipation system is abnormal, and limits the maximum allowable opening of the second expansion valve 12 to a lower level to reduce the bypass refrigerant flow and reduce the discharge temperature and load of the compressor 16.

[0064] Working principle: When ice making starts, the controller 20 first reads the pressure value of the pressure sensor 13 and determines the initial opening of the second expansion valve 12 based on the pressure value by consulting the "Pressure-Optimal Opening Mapping Table". When the pressure is within the allowable range, the controller 20 controls the second expansion valve 12 to open, allowing the refrigerant at the outlet of the dryer filter 14 to enter the refrigerant inlet 103 after being throttled by the second expansion valve 12. When the pressure is abnormally low, the controller 20 forcibly closes the second expansion valve 12 and stops ice making, prioritizing the safe operation of the compressor 16. When the pressure is abnormally high, the controller 20 limits the maximum allowable opening of the second expansion valve 12 to prevent system overload.

[0065] In summary, by using the compressor 16, condenser 15, dryer filter 14, first expansion valve 11, evaporator 10, second expansion valve 12 and pressure sensor 13 in combination, a refrigerant branch for subcooling ice making can be formed in the original refrigeration circuit of the refrigerator, and refrigerant distribution protection control can be performed according to the system pressure status, solving the problems of complex structure, large space occupation and unstable refrigerant distribution of independent refrigeration circuits.

[0066] Example 4 Reference Figure 3 This is the fourth embodiment of the present invention. Unlike the previous embodiment, this embodiment further provides a backflow protection structure after the refrigerant outlet 104, which solves the problem that the refrigerant may carry liquid back to the compressor 16 after flowing out of the shell-and-tube subcooler 1, causing liquid slugging.

[0067] Specifically, the gas-liquid separator 19 is connected between the refrigerant outlet 104 and the compressor 16. The gas-liquid separator 19 includes an inlet, a gas phase outlet, and a liquid phase outlet. The inlet is connected to the refrigerant outlet 104, the gas phase outlet is connected to the suction side of the compressor 16 via a first one-way valve 17, and the liquid phase outlet is connected to the crankcase of the compressor 16 or a suction pipe section near the crankcase via a second one-way valve 18. By providing the gas-liquid separator 19, the refrigerant flowing from the refrigerant outlet 104 can be separated into gas and liquid phases, reducing the risk of liquid refrigerant directly entering the compressor 16.

[0068] Furthermore, by setting a first one-way valve 17, gaseous refrigerant can be easily returned to the suction side of the compressor 16, while preventing refrigerant backflow; by setting a second one-way valve 18, liquid refrigerant or oil-containing liquid can be easily returned to the crankcase of the compressor 16 or the suction pipe section near the crankcase, while reducing the risk of backflow.

[0069] The second temperature sensor 6 is located at or near the refrigerant outlet 104 and is connected to the controller 20. By installing the second temperature sensor 6, the refrigerant temperature at the refrigerant outlet 104 can be detected. When the refrigerant temperature at the refrigerant outlet 104 is abnormally low, it indicates a risk of insufficiently evaporated refrigerant flowing out from the coaxial subcooler 1. The controller 20 can then promptly reduce or close the second expansion valve 12.

[0070] Preferably, the controller 20 performs protective control based on the refrigerant temperature detected by the second temperature sensor 6. When the refrigerant temperature is lower than the first refrigerant temperature threshold, the controller 20 reduces the opening of the second expansion valve 12; when the refrigerant temperature is lower than the second refrigerant temperature threshold, the controller 20 closes the second expansion valve 12 and stops the water pump 4, wherein the second refrigerant temperature threshold is lower than the first refrigerant temperature threshold. For example, when the refrigerant temperature at the refrigerant outlet 104 is lower than -10°C, the controller 20 limits the increment of the opening of the second expansion valve 12; when the refrigerant temperature at the refrigerant outlet 104 is lower than -12°C, the controller 20 forcibly closes the second expansion valve 12 and stops the water pump 4, entering a safety reset state.

[0071] Working principle: After exchanging heat with the ice-making water in the inner tube 102 of the coaxial subcooler 1, the refrigerant flows out from the refrigerant outlet 104 and enters the gas-liquid separator 19 through the inlet. The gas-liquid separator 19 separates the refrigerant into gas and liquid phases. The gaseous refrigerant returns to the suction side of the compressor 16 through the gas phase outlet and the first one-way valve 17, while the liquid refrigerant or oil-containing liquid returns to the crankcase of the compressor 16 or the suction pipe section near the crankcase through the liquid phase outlet and the second one-way valve 18. When the second temperature sensor 6 detects that the temperature of the refrigerant outlet 104 is too low, the controller 20 limits or closes the second expansion valve 12, reducing the amount of refrigerant entering the coaxial subcooler 1 from the source.

[0072] In summary, by using a gas-liquid separator 19, an inlet, a gas phase outlet, a liquid phase outlet, a first one-way valve 17, a second one-way valve 18, a second temperature sensor 6, and a controller 20 in conjunction, the risk of refrigerant backflow and liquid slugging in the compressor 16 can be reduced, and the problem of insufficient return gas safety after the subcooled ice-making branch is connected to the refrigerator refrigeration circuit can be solved.

[0073] Example 5 Reference Figure 3 and Figure 4 This is the fifth embodiment of the present invention. Unlike the previous embodiment, this embodiment further provides an ice-making water delivery and nucleation structure, which solves the problems that supercooled water is prone to premature nucleation due to disturbance before entering the ice-making mold 9, pipe freezing, and unstable nucleation position after entering the ice-making mold 9.

[0074] Specifically, the water storage box 2 is connected to the water inlet 106 of the shell-and-tube subcooler 1 via the water inlet valve 3 and the water pump 4, and the water outlet 105 is connected to the ice-making mold 9 via the subcooled water delivery pipe. By setting up the water storage box 2, it is convenient to store the ice-making water to be made; by setting up the water inlet valve 3, it is convenient to control whether water is supplied to the shell-and-tube subcooler 1; by setting up the water pump 4, it is convenient to control the flow rate of the ice-making water and the heat exchange time of the ice-making water in the inner tube 102; by setting up the subcooled water delivery pipe, it is convenient to deliver the subcooled water output from the water outlet 105 to the ice-making mold 9.

[0075] Furthermore, the first temperature sensor 5 is located at or near the water outlet 105, and is connected to the controller 20. By setting the first temperature sensor 5, the controller 20 can easily obtain the subcooled water temperature in real time and adjust the inlet valve 3, water pump 4, and second expansion valve 12 according to the water temperature. The target subcooling temperature range can be set to -4.0℃ ± 0.5℃, or to -4.5℃ to -3.5℃; when a wider protection range is needed, the allowable subcooling temperature range can be controlled between -3℃ and -5℃.

[0076] The subcooled water delivery pipe includes a low-disturbance section extending from the water outlet 105 to the ice-making mold 9. The inner wall roughness of the low-disturbance section is less than or equal to 0.4 μm, the inner diameter of the low-disturbance section is 2.0 mm to 4.0 mm, the bending radius of the low-disturbance section is not less than three times its outer diameter, and an insulation layer is provided on the outside of the low-disturbance section. By setting up the low-disturbance section, frictional disturbance, eddy current disturbance, and local pressure fluctuations of the subcooled water during the delivery process can be reduced; by setting up the insulation layer, the influence of external temperature fluctuations on the state of the subcooled water can be reduced.

[0077] Preferably, the material for the low-disturbance pipe section can be 316L stainless steel, PFA pipe, or FEP pipe to improve the smoothness and chemical stability of the pipe inner wall and reduce the possibility of impurity particles acting as nucleation nuclei for heterogeneous phases. A smooth transition structure is provided at the connection between the low-disturbance pipe section and the ice-making mold 9. This smooth transition structure can be a chamfered, arc-shaped, or tapered transition structure. By providing a smooth transition structure, the steps, sharp bends, and abrupt changes in cross-section that occur when subcooled water enters the ice-making mold 9 from the subcooled water delivery pipe can be reduced, thereby lowering the risk of premature nucleation and pipe icing.

[0078] Furthermore, the ice-making mold 9 is provided with a piezoelectric ceramic sheet 22, which is connected to the controller 20 via a wire 21. The piezoelectric ceramic sheet 22 is disposed on the bottom or side wall of the ice-making mold 9, and in this embodiment, it is preferably disposed in the central area of ​​the bottom of the ice-making mold 9. The thickness of the piezoelectric ceramic sheet 22 is 0.2 mm to 0.5 mm, the vibration frequency is 20 kHz to 40 kHz, and the amplitude is 1 μm to 10 μm. The piezoelectric ceramic sheet 22 can be made of lead zirconate titanate piezoelectric ceramic, with electrodes disposed on its surface, and fixed to the bottom of the ice-making mold 9 with thermally conductive adhesive. By providing the piezoelectric ceramic sheet 22, the controller 20 can drive the piezoelectric ceramic sheet 22 to generate high-frequency micro-amplitude vibration at the moment when supercooled water enters the ice-making mold 9, so that the supercooled water nucleates in a controlled manner within the ice-making mold 9.

[0079] Working principle: After being treated by the shell-and-tube subcooler 1, the ice-making water is output from the water outlet 105 and enters the ice-making mold 9 through the subcooled water delivery pipe. Because the subcooled water delivery pipe includes a low-disturbance section with a small inner wall roughness, suitable inner diameter, large bending radius, and insulation layer, the subcooled water is less likely to nucleate prematurely due to friction, eddies, or abrupt changes in cross-section before entering the ice-making mold 9. After the subcooled water enters the ice-making mold 9, the controller 20 applies a high-frequency AC voltage to the piezoelectric ceramic plate 22 through the wire 21, causing the piezoelectric ceramic plate 22 to generate high-frequency micro-amplitude vibration. This causes the subcooled water entering the ice-making mold 9 to be preferentially triggered to nucleate near the piezoelectric ceramic plate 22 and gradually expand to the surrounding water.

[0080] In summary, by using the water storage box 2, water inlet valve 3, water pump 4, first temperature detection element 5, subcooled water delivery pipe, low-disturbance pipe section, smooth transition structure, insulation layer, ice-making mold 9, controller 20, wire 21 and piezoelectric ceramic sheet 22 in combination, the subcooled water can be kept in a liquid state during transportation and can be controlled to nucleate after entering the ice-making mold 9, thus solving the problems of premature freezing and blockage of subcooled water and unstable nucleation position.

[0081] Example 6 Reference Figure 3 This is the sixth embodiment of the present invention. Unlike the previous embodiment, this embodiment further provides a drainage structure for the solenoid valve 7 and the water receiving component 8, which solves the problem of residual water freezing and clogging near the inner pipe 102, water outlet 105 and subcooled water delivery pipe in a low-temperature environment after ice making.

[0082] Specifically, solenoid valve 7 is used as a drain valve. It is located at the lowest point of the shell-and-tube subcooler 1 and is connected to the inner tube 102. Solenoid valve 7 is installed at the lowest point of the outlet end of the inner tube 102, utilizing gravity drainage to reduce residual water retention. By installing solenoid valve 7, residual water in the inner tube 102 and / or the subcooled water delivery pipe can be easily drained after ice making.

[0083] Furthermore, the outlet of the solenoid valve 7 is connected to the water receiving component 8, which can be a drip tray or a drain pipe. By providing the water receiving component 8, residual water discharged from the solenoid valve 7 can be easily received, preventing residual water from dripping directly into the refrigerator or the ice-making area.

[0084] The solenoid valve 7 is connected to the controller 20. After ice making is completed, the controller 20 can control the second expansion valve 12 to close and control the water inlet valve 3 and water pump 4 to stop working. Then, the solenoid valve 7 is opened to allow residual water near the inner pipe 102, water outlet 105 and / or subcooled water delivery pipe to be discharged into the water receiving component 8.

[0085] Preferably, the solenoid valve 7 is normally closed, remaining closed during normal ice-making and opening 5 to 10 seconds after ice-making ends, with an opening duration of 3 to 5 seconds. Before the solenoid valve 7 opens, the controller 20 first stops the water pump 4 and waits approximately 2 seconds to eliminate water hammer impact; then it controls the solenoid valve 7 to open, allowing residual water to flow into the water receiving component 8 under gravity; after the solenoid valve 7 has been open for a preset duration, it is closed by the controller 20. The solenoid valve 7 can be a normally closed electromagnetic drain valve, closing upon power failure to prevent accidental leakage, and its larger flow area improves the efficiency of residual water discharge.

[0086] Working principle: After ice making is completed, the controller 20 closes the second expansion valve 12, stops supplying refrigerant to the shell-and-tube subcooler 1, and simultaneously closes the water inlet valve 3 and stops the water pump 4. After the water pump 4 stops and a preset time is waited, the controller 20 opens the solenoid valve 7, allowing residual water near the inner pipe 102, water outlet 105, and / or subcooled water delivery pipe to drain into the water receiving component 8. After the drainage continues for a preset time, the controller 20 closes the solenoid valve 7, putting the system into standby mode.

[0087] In summary, by using the solenoid valve 7, the water receiving component 8, and the controller 20 in conjunction, residual water in the shell-and-tube subcooler 1 and the subcooled water delivery pipe can be discharged in a timely manner, thus solving the problem of residual water freezing and clogging the inner pipe 102 and the subcooled water delivery pipe after shutdown.

[0088] Example 7 Reference Figures 3 to 5 This is the seventh embodiment of the present invention. Unlike the previous embodiment, this embodiment further provides a dual-parameter coordinated control method based on water temperature and refrigerant temperature, which solves the problem that it is difficult to stably obtain subcooled water when relying solely on the fixed flow rate of water pump 4 or the fixed opening degree of the second expansion valve 12.

[0089] Specifically, the controller 20 acquires the water temperature at the water outlet 105 detected by the first temperature sensor 5 and the refrigerant temperature at the refrigerant outlet 104 detected by the second temperature sensor 6 at a sampling frequency of 10Hz. In order to reduce sensor noise interference and malfunctions caused by temperature detection fluctuations, the controller 20 processes three consecutive sampled values ​​using a median filtering algorithm and takes the median value as the current valid temperature value.

[0090] Furthermore, the system operation process includes a precooling stage, a steady-state subcooling stage, and a protection stage. During the precooling stage, the controller 20 controls the second expansion valve 12 to maintain a preset precooling opening, for example, 75% to 80%, while simultaneously stopping the water pump 4, allowing the shell-and-tube subcooler 1 to first establish a stable low-temperature environment. The precooling duration can be 30 to 60 seconds, or it can continue until the value detected by the first temperature sensor 5 is repeatedly below -2°C or below -1°C.

[0091] During the steady-state subcooling phase, when the first temperature sensor 5 detects that the water temperature at the water outlet 105 is between -4.5℃ and -3.5℃, and the second temperature sensor 6 detects that the refrigerant temperature at the refrigerant outlet 104 is between -10℃ and -6℃, the controller 20 maintains its current operating state and makes small adjustments to the second expansion valve 12 and the water pump 4 through a closed-loop regulation method. This closed-loop regulation method can be PID regulation or other control methods that can provide feedback adjustment based on the detected temperature. The controller 20 sets an adjustment dead zone of ±0.3℃, meaning that no adjustment is made when the water temperature fluctuates within the target value of ±0.3℃, to prevent frequent operation of the valves and water pump. The single adjustment range of the second expansion valve 12 does not exceed 2%, and the single adjustment range of the water pump 4 does not exceed 5Hz, to avoid water flow fluctuations or valve wear caused by frequent adjustments.

[0092] Preferably, when the first temperature sensor 5 detects that the water temperature at the water outlet 105 is higher than the upper limit of the target subcooling temperature range, the controller 20 preferentially increases the opening of the second expansion valve 12; when the opening of the second expansion valve 12 has reached the upper limit but the water temperature is still too high, the controller 20 reduces the flow rate of the water pump 4, thereby increasing the residence time of the ice-making water in the inner pipe 102. When the first temperature sensor 5 detects that the water temperature at the water outlet 105 is lower than the lower limit of the target subcooling temperature range, the controller 20 reduces the opening of the second expansion valve 12 or increases the flow rate of the water pump 4 to reduce the risk of premature freezing.

[0093] Furthermore, when the second temperature sensor 6 detects that the refrigerant temperature at the refrigerant outlet 104 is lower than the first refrigerant temperature threshold, the controller 20 reduces the opening of the second expansion valve 12; when the second temperature sensor 6 detects that the refrigerant temperature at the refrigerant outlet 104 is lower than the second refrigerant temperature threshold, the controller 20 closes the second expansion valve 12 and stops the water pump 4. The first refrigerant temperature threshold can be -10℃, and the second refrigerant temperature threshold can be -12℃. When the first temperature sensor 5 detects that the water temperature at the water outlet 105 is lower than the water temperature protection threshold, the controller 20 reduces the opening of the second expansion valve 12 and maintains or increases the flow rate of the water pump 4; the water temperature protection threshold can be -5.0℃, and the shutdown threshold can be -5.5℃.

[0094] Working Principle: After ice making begins, the controller 20 first enters the pre-cooling stage, causing the shell-and-tube subcooler 1 to reach a low temperature. After pre-cooling is complete, the controller 20 activates the inlet valve 3 and the water pump 4, allowing the ice-making water in the water storage box 2 to enter the inner pipe 102. The controller 20 continuously reads the detection results of the first temperature sensor 5 and the second temperature sensor 6, and adjusts the second expansion valve 12 based on the water temperature first, then adjusts the water pump 4 based on the adjustment limit of the second expansion valve 12, while simultaneously implementing safety constraints based on the refrigerant temperature. When the refrigerant temperature is abnormally low or the water temperature is too low, the controller 20 enters the protection stage, limiting or closing the second expansion valve 12 and stopping the water pump 4.

[0095] In summary, by using the first temperature detection element 5, the second temperature detection element 6, the water pump 4, the second expansion valve 12, and the controller 20 together, a dual-parameter collaborative control mode with refrigerant side priority, water side assistance, and refrigerant temperature constraint can be formed, which can solve the problems of insufficient subcooling, excessive subcooling, pipeline freezing, and the risk of liquid slugging in the compressor 16.

[0096] Example 8 Reference Figure 3 and Figure 5 This is the eighth embodiment of the present invention. Unlike the previous embodiment, this embodiment further provides a first-stage water treatment and typical working condition control process, which solves the problem that residual water or water with uneven temperature in the pipe directly enters the ice mold 9 during the initial stage of ice making, resulting in unstable ice quality.

[0097] Specifically, during the precooling stage, the controller 20 controls the second expansion valve 12 to open to the preset precooling opening degree, such as 80%, and controls the water pump 4 to stop, waiting for 30 to 60 seconds, or waiting for the first temperature detection element 5 to detect that the temperature at the water outlet 105 reaches the preset entry temperature, such as -2℃ to -1℃.

[0098] Furthermore, after precooling, the controller 20 starts the water pump 4 at a lower frequency, such as 20Hz, to allow the ice-making water in the water storage box 2 to enter the inner pipe 102. At this time, the controller 20 opens the solenoid valve 7, preventing the first stage of water from entering the ice-making mold 9, and instead draining it into the water receiving component 8 through the solenoid valve 7. In this way, the uneven temperature of the first stage of water in the inner pipe 102 and near the water outlet 105 can be discharged, ensuring that the temperature of the subcooled water that subsequently enters the ice-making mold 9 is stable.

[0099] The initial water discharge process can last from 5 to 10 seconds, or until the first temperature sensor 5 detects that the water temperature at the water outlet 105 has stabilized at -4.5℃ to -3.5℃ and remains there for 2 seconds. After the initial water discharge is completed, the controller 20 closes the solenoid valve 7 and increases the water pump 4 to its operating frequency, for example, 50Hz to 80Hz, so that the subcooled water enters the ice-making mold 9.

[0100] Preferably, under standard operating conditions, the inlet water temperature is 20℃, the refrigerant evaporation temperature is -18℃, and the target water temperature is -4.0℃±0.5℃. During the pre-cooling phase from 0 seconds to 30 seconds, the controller 20 can control the second expansion valve 12 to adjust from 75% to 80%, the water pump 4 stops, and the water temperature drops from 15℃ to 5℃. During the switching phase from 30 seconds to 45 seconds, the controller can control the second expansion valve 12 to adjust from 80% to 60%, the water pump 4 increases from 0Hz to 40Hz, and the water temperature drops from 5℃ to -3.8℃. During the steady state from 45 seconds to 60 seconds, the second expansion valve 12 opens to about 55%, the water pump 4 operates at about 35Hz, and the water temperature is about -4.1℃.

[0101] Under high-temperature inlet water conditions, when the inlet water temperature is 35℃, the controller 20 can extend the switching process. After the pre-cooling stage, the water temperature drops from 30℃ to 15℃. During the switching stage, the water temperature drops from 15℃ to 2℃. Subsequently, the second expansion valve 12 opens to about 58%, and the water pump 4 operates at about 25Hz, stabilizing the water temperature to about -4.2℃.

[0102] When the cold source is insufficient and the refrigerant evaporation temperature is -10℃, the water temperature drops from 15℃ to 8℃ after the pre-cooling stage. The controller 20 can reduce the frequency of the water pump 4 to 30Hz and cooperate with the opening of the second expansion valve 12 to about 55% to make the water temperature reach about -4.0℃.

[0103] Working principle: After ice making is started, controller 20 first precools the jacketed subcooler 1, then starts water pump 4 and opens solenoid valve 7 to discharge the first stage of water. When the first temperature sensor 5 detects that the water temperature at water outlet 105 is stable, controller 20 closes solenoid valve 7 and allows subcooled water to enter ice mold 9. After the subcooled water enters ice mold 9, controller 20 drives piezoelectric ceramic plate 22 through wire 21, causing the subcooled water to nucleate and freeze inside ice mold 9. Under different inlet water temperature and refrigerant evaporation temperature conditions, controller 20 adaptively adjusts the opening of second expansion valve 12 and the frequency of water pump 4 to stabilize the water temperature at water outlet 105 within the target subcooling temperature range.

[0104] In summary, by using the second expansion valve 12, the first temperature detection element 5, the water pump 4, the solenoid valve 7, the water receiving component 8, the ice-making mold 9, the controller 20, and the piezoelectric ceramic plate 22 together, it is possible to prevent water with uneven initial temperature from directly entering the ice-making mold 9, thus solving the problems of unstable quality of supercooled water and inconsistent ice nucleation effect in the initial stage of startup.

[0105] Example 9 Reference Figure 3 and Figure 5 This is the ninth embodiment of the present invention. Unlike the previous embodiment, this embodiment further provides a complete ice-making control process, which solves the problem of unclear connection between the precooling, water supply, subcooling, nucleation and venting steps in the ice-making process.

[0106] Specifically, after responding to the ice-making command, the controller 20 first controls the second expansion valve 12 to open, allowing the refrigerant in the refrigerator's refrigeration circuit to enter the refrigerant flow channel of the coaxial subcooler 1 through the branch position between the outlet of the dryer filter 14 and the first expansion valve 11. During the pre-cooling stage, the controller 20 stops the water pump 4 from supplying water and keeps the second expansion valve 12 at the preset pre-cooling opening.

[0107] Furthermore, after precooling, the controller 20 controls the inlet valve 3 and the water pump 4 to send the ice-making water in the water storage box 2 into the inner pipe 102, and to make the flow direction of the ice-making water in the inner pipe 102 opposite to the flow direction of the refrigerant in the refrigerant channel. The controller 20 obtains the water temperature at the water outlet 105 detected by the first temperature sensor 5 and the refrigerant temperature at the refrigerant outlet 104 detected by the second temperature sensor 6, and adjusts the inlet valve 3, the water pump 4, and the second expansion valve 12 according to the water temperature and the refrigerant temperature.

[0108] Specifically, when the water temperature at water outlet 105 is higher than the upper limit of the target subcooling temperature range, controller 20 prioritizes increasing the opening of the second expansion valve 12; when the opening of the second expansion valve 12 reaches the upper limit and the water temperature is still too high, the water supply flow of pump 4 is reduced; when the water temperature at water outlet 105 is lower than the lower limit of the target subcooling temperature range, controller 20 either reduces the opening of the second expansion valve 12 or increases the water supply flow of pump 4. Through these methods, the ice-making water output from water outlet 105 is kept in a subcooled state suitable for nucleation.

[0109] Preferably, after the subcooled water treated by the shell-and-tube subcooler 1 enters the ice-making mold 9 through the subcooled water delivery pipe, the controller 20 drives the piezoelectric ceramic plate 22 through the wire 21 to cause the subcooled water to nucleate inside the ice-making mold 9. After ice making is completed, the controller 20 closes the second expansion valve 12, stops the water inlet valve 3 and the water pump 4, and controls the solenoid valve 7 to open for a preset time to discharge the residual water in the inner pipe 102 and / or the subcooled water delivery pipe.

[0110] Working principle: The controller 20 sequentially performs refrigerant precooling, ice-making water delivery, counter-current heat exchange, temperature detection, flow regulation, mold nucleation, and residual water drainage. By providing feedback on the ice-making water temperature and refrigerant temperature through the first temperature sensor 5 and the second temperature sensor 6, the controller 20 ensures that the ice-making water remains subcooled before entering the ice-making mold 9. Nucleation is triggered by the piezoelectric ceramic plate 22, allowing the subcooled water to freeze within the ice-making mold 9. Draining residual water through the solenoid valve 7 reduces freezing and blockage after shutdown.

[0111] In summary, by coordinating the use of the controller 20 with the second expansion valve 12, the inlet valve 3, the water pump 4, the first temperature sensor 5, the second temperature sensor 6, the piezoelectric ceramic plate 22, and the solenoid valve 7, a complete ice-making control process can be formed, solving the problem of discontinuous control between the production, transportation, nucleation, and shutdown venting of subcooled water.

[0112] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An ice-making system, characterized in that: It includes a refrigerator refrigeration circuit, a water storage box, an ice-making mold, a sleeve-type subcooler, a water-side conveying assembly, a second electronic expansion valve, a temperature detection assembly, a gas-liquid separator, and a controller; The refrigerator refrigeration circuit includes a compressor, a condenser, a dryer filter, a first throttling element, and an evaporator connected in sequence. A branch point is provided between the outlet of the dryer filter and the first throttling element, and the outlet of the evaporator is connected to the suction side of the compressor. The sleeve-type subcooler is located between the water storage box and the ice-making mold, and includes an inner tube and an outer tube sleeved on the outside of the inner tube. The inner tube forms a water flow channel, and a refrigerant flow channel is formed between the inner tube and the outer tube. The water-side conveying assembly includes an inlet valve and a water pump, and connects the water storage box and the water inlet of the inner pipe. The water outlet of the inner pipe is connected to the ice-making mold via a subcooled water conveying pipe. The refrigerant inlet of the refrigerant flow channel is connected to the branch point via the second electronic expansion valve, and the refrigerant outlet of the refrigerant flow channel is connected to the return gas side of the compressor via the gas-liquid separator; The water inlet and the refrigerant outlet are located at the first end of the shell-and-tube subcooler, and the water outlet and the refrigerant inlet are located at the second end of the shell-and-tube subcooler; The temperature detection component includes a first temperature detection element for detecting the water temperature at the water outlet and a second temperature detection element for detecting the refrigerant temperature at the refrigerant outlet. The controller is electrically connected to the water-side delivery assembly, the second electronic expansion valve, the first temperature sensor, and the second temperature sensor, and is configured to adjust the water supply status and the opening degree of the second electronic expansion valve according to the water temperature and the refrigerant temperature. The water inlet area of ​​the ice-making mold is equipped with a nucleation trigger.

2. The ice-making system as described in claim 1, characterized in that: The shell-and-tube subcooler includes a first end flow collection structure and a second end flow collection structure. The water inlet and the refrigerant outlet are located in the first end flow collection structure, and the water outlet and the refrigerant inlet are located in the second end flow collection structure. The water inlet is connected to one end of the inner pipe, the water outlet is connected to the other end of the inner pipe, and the refrigerant inlet and the refrigerant outlet are respectively connected to both ends of the refrigerant flow channel.

3. The ice-making system as described in claim 1, characterized in that: The inner tube and the outer tube are coaxially arranged, and a plurality of support rings are axially spaced between the inner tube and the outer tube. The support rings are connected to the inner tube and / or the outer tube to define the annular cross-section of the refrigerant flow channel.

4. An ice-making system as described in claim 2, characterized in that: The inner tube is connected to the first end flow collecting structure and / or the second end flow collecting structure via a compression fitting, and an elastic sealing ring is provided at the compression fitting. An expansion compensation section is provided near at least one end of the outer tube. The expansion compensation section is a corrugated compensation section, a U-shaped compensation section, or a thin-walled bending section.

5. An ice-making system as described in claim 1, characterized in that: The subcooled water delivery pipe includes a low-disturbance pipe section extending from the water outlet to the ice-making mold. The inner wall roughness of the low-disturbance pipe section is less than or equal to 0.4 μm, and a smooth transition structure is provided at the connection between the low-disturbance pipe section and the ice-making mold.

6. An ice-making system as described in claim 5, characterized in that: The low-disturbance pipe section is made of 316L stainless steel, PFA, or FEP pipe. The inner diameter of the low-disturbance pipe section is 2.0mm to 4.0mm. The bending radius of the low-disturbance pipe section is not less than three times its outer diameter. The low-disturbance pipe section is provided with an insulation layer on its outer side.

7. An ice-making system as described in claim 1, characterized in that: The nucleation triggering part includes at least one of piezoelectric ceramic sheet, roughened surface, micro-protrusion, micro-groove or turbulence structure; When the nucleation triggering part includes a piezoelectric ceramic sheet, the piezoelectric ceramic sheet is fixed to the bottom or side wall of the ice-making mold and connected to the controller via a wire.

8. An ice-making system as described in claim 7, characterized in that: The piezoelectric ceramic sheet has a thickness of 0.2 mm to 0.5 mm, a vibration frequency of 20 kHz to 40 kHz, and an amplitude of 1 μm to 10 μm. The piezoelectric ceramic sheet is fixed to the ice-making mold by thermally conductive adhesive.

9. An ice-making system as described in claim 1, characterized in that: The gas-liquid separator includes an inlet, a gas phase outlet, and a liquid phase outlet. The inlet is connected to the refrigerant outlet. The gas phase outlet is connected to the suction side of the compressor via a first one-way valve. The liquid phase outlet is connected to the crankcase of the compressor or a suction pipe section near the crankcase via a second one-way valve.

10. An ice-making system as described in claim 1, characterized in that: A pressure sensor is installed on the pipeline between the outlet of the dryer filter and the branch point, and the pressure sensor is connected to the controller. The controller determines the initial opening or maximum permissible opening of the second electronic expansion valve based on the pressure value of the pressure sensor.

11. An ice-making system as described in claim 1, characterized in that: A vent valve is provided at the lower position of the shell-and-tube subcooler, and the vent valve is electrically connected to the controller. The inlet of the vent valve is connected to the inner pipe, and the outlet of the vent valve is connected to a water receiving pan or a drain pipe.

12. An ice-making control method, applied to the ice-making system according to any one of claims 1 to 11, characterized in that, include: In response to the ice-making command, the second electronic expansion valve is opened, allowing the refrigerant in the refrigerator's refrigeration circuit to enter the refrigerant flow channel through the branch point; During the pre-cooling stage, the water-side delivery assembly stops supplying water, and the second electronic expansion valve maintains a preset pre-cooling opening. After precooling is completed, the water-side delivery assembly is controlled to send the ice-making water in the water storage box into the inner tube, and the flow direction of the ice-making water in the inner tube is opposite to the flow direction of the refrigerant in the refrigerant channel. The water outlet temperature detected by the first temperature sensor and the refrigerant outlet temperature detected by the second temperature sensor are obtained. Adjust the water supply status of the water-side delivery assembly and the opening degree of the second electronic expansion valve according to the water temperature and the refrigerant temperature; The subcooled water, after being treated by the shell-and-tube subcooler, is sent into the ice-making mold through the subcooled water delivery pipe, and the nucleation triggering part triggers the nucleation of the subcooled water.

13. The ice-making control method as described in claim 12, characterized in that: During the steady-state subcooling stage, adjusting the water supply status of the water-side conveying assembly and the opening degree of the second electronic expansion valve according to the water outlet temperature includes: When the water temperature is higher than the upper limit of the target subcooling temperature range, the opening of the second electronic expansion valve is increased first. When the opening of the second electronic expansion valve reaches its upper limit and the water temperature is still higher than the upper limit of the target subcooling temperature range, the water supply flow rate of the water-side delivery component is reduced. When the water temperature is lower than the lower limit of the target subcooling temperature range, reduce the opening of the second electronic expansion valve or increase the water supply flow rate of the water-side delivery assembly.

14. The ice-making control method as described in claim 12, characterized in that: Protection control is implemented based on the refrigerant outlet temperature and the water outlet temperature, including: When the refrigerant temperature is lower than the first refrigerant temperature threshold, the opening of the second electronic expansion valve is reduced; When the refrigerant temperature is lower than the second refrigerant temperature threshold, the second electronic expansion valve is closed and the water-side delivery assembly is stopped; Wherein, the second refrigerant temperature threshold is lower than the first refrigerant temperature threshold; When the water temperature is lower than the water temperature protection threshold, the opening of the second electronic expansion valve is reduced, and the water supply flow of the water-side delivery assembly is maintained or increased.

15. The ice-making control method as described in claim 12, characterized in that: The ice-making system includes a vent valve located at the low position of the shell-and-tube subcooler. The inlet of the vent valve is connected to the inner tube, and the outlet of the vent valve is connected to a water receiving pan or a drain pipe. After ice making is completed, the second electronic expansion valve is closed, the water-side delivery assembly is stopped supplying water, and the drain valve is opened for a preset time to drain the residual water in the inner pipe and / or the subcooled water delivery pipe.

16. An ice-making apparatus, characterized in that: It includes an outer casing and an ice-making system as described in any one of claims 1 to 11 disposed within the outer casing.

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