A control method and apparatus for a refrigeration system

Abstract

This invention discloses a control method and apparatus for a refrigeration system. The control method includes: acquiring the freezing point temperature of the refrigerant in the refrigeration system; determining the relationship between the freezing point temperature and a preset temperature value; and controlling the operating states of a solenoid valve and an evaporation pressure regulating valve in the refrigeration system based on this relationship. The control method and apparatus for the refrigeration system provided by this invention can ensure the reliability of the refrigeration system's operation.

Description

[0001] This application is a divisional application of the patent application filed on November 28, 2022, with application number CN2022115060989 and patent title "A control method, device and refrigeration system for a refrigeration system". Technical Field

[0002] The present invention relates to refrigeration technology, and more particularly to a control method and apparatus for a refrigeration system. Background Technology

[0003] With the advancement of technology, the improvement of people's living standards, and the increasing demands for quality of life, more and more equipment, items, or spaces have higher requirements for temperature. For equipment that requires a low-temperature environment, a refrigeration system is needed to provide that environment.

[0004] Currently, existing refrigeration systems are prone to compressor shutdown under low-temperature protection when undergoing low-temperature testing, especially when using refrigerants with freezing point limitations. This can also lead to weak cooling capacity when the system recovers to normal temperature, severely affecting the progress and effectiveness of the entire test, and even causing the refrigeration system to malfunction and compromise its reliability. Summary of the Invention

[0005] This invention provides a control method and apparatus for a refrigeration system to ensure the reliability of the refrigeration system's operation.

[0006] In a first aspect, embodiments of the present invention provide a control method for a refrigeration system. The refrigeration system includes a compressor, an evaporator, a condenser, an evaporation pressure regulating valve, a solenoid valve, and a controller. The controller is electrically connected to the compressor, the evaporation pressure regulating valve, and the solenoid valve. The compressor is connected to the condenser, and the condenser is connected to the evaporator. The evaporator is connected to the compressor via the evaporation pressure regulating valve and the solenoid valve. The evaporation pressure regulating valve and the solenoid valve are located on different branches. Both the evaporation pressure regulating valve and the solenoid valve are located near the outlet of the evaporator. The control method is executed by the controller and includes:

[0007] To obtain the freezing point temperature of the refrigerant in the refrigeration system;

[0008] Determine the relationship between the freezing point temperature and the preset temperature value based on the freezing point temperature and the preset temperature value.

[0009] When the freezing point temperature is higher than the preset temperature value, adjust the adjustment threshold of the evaporation pressure regulating valve.

[0010] Optionally, when the freezing point temperature is higher than a preset temperature value, the adjustment threshold of the evaporation pressure regulating valve is adjusted, including:

[0011] When the freezing point temperature is higher than the preset temperature value, and the difference between the freezing point temperature and the preset temperature value is within the preset first range, the adjustment threshold of the evaporation pressure regulating valve is the preset first adjustment threshold.

[0012] When the freezing point temperature is higher than the preset temperature value, and the difference between the freezing point temperature and the preset temperature value is within the preset second range, the adjustment threshold of the evaporation pressure regulating valve is the preset second adjustment threshold.

[0013] Optionally, the first preset range is smaller than the second preset range, and the first preset adjustment threshold is smaller than the second preset adjustment threshold.

[0014] Optionally, the above control method further includes:

[0015] When adjusting the adjustment threshold of the evaporation pressure regulating valve, the control solenoid valve is in the closed state.

[0016] Optionally, the threshold can be adjusted between 0 and 100%.

[0017] In a second aspect, embodiments of the present invention provide a control device for a refrigeration system. The refrigeration system includes a compressor, an evaporator, a condenser, an evaporation pressure regulating valve, a solenoid valve, and a controller. The controller is electrically connected to the compressor, the evaporation pressure regulating valve, and the solenoid valve. The compressor is connected to the condenser, and the condenser is connected to the evaporator. The evaporator is connected to the compressor via the evaporation pressure regulating valve and the solenoid valve. The evaporation pressure regulating valve and the solenoid valve are located on different branches. Both the evaporation pressure regulating valve and the solenoid valve are located near the outlet of the evaporator. The control device is integrated into the controller and includes:

[0018] The temperature acquisition module is used to acquire the freezing point temperature of the refrigerant in the refrigeration system.

[0019] The size determination module is used to determine the relationship between the freezing point temperature and the preset temperature value based on the freezing point temperature and the preset temperature value.

[0020] The status control module includes a threshold adjustment unit, which is used to adjust the adjustment threshold of the evaporation pressure regulating valve when the freezing point temperature is higher than a preset temperature value.

[0021] The threshold adjustment unit includes:

[0022] The first regulating subunit is used to adjust the regulating threshold of the evaporation pressure regulating valve to a preset first regulating threshold when the freezing point temperature is higher than the preset temperature value and the difference between the freezing point temperature and the preset temperature value is within a preset first range.

[0023] The second regulating subunit is used to adjust the regulating threshold of the evaporation pressure regulating valve to the preset second regulating threshold when the freezing point temperature is higher than the preset temperature value and the difference between the freezing point temperature and the preset temperature value is within the preset second range.

[0024] Optionally, the first preset range is smaller than the second preset range, and the first preset adjustment threshold is smaller than the second preset adjustment threshold.

[0025] Optionally, the control device may also include:

[0026] The solenoid valve control module is used to control the solenoid valve to be in the closed state when the threshold adjustment unit adjusts the adjustment threshold of the evaporation pressure regulating valve.

[0027] The control method and apparatus for a refrigeration system provided in this invention obtain the freezing point temperature of the refrigerant in the refrigeration system; determine the relationship between the freezing point temperature and a preset temperature value; and control the operating state of the solenoid valve and the evaporation pressure regulating valve in the refrigeration system according to this relationship. The control method and apparatus for a refrigeration system provided in this invention control the operating state of the solenoid valve and the evaporation pressure regulating valve in the refrigeration system according to the relationship between the freezing point temperature and the preset temperature value. For example, when the freezing point temperature is higher than the preset temperature value, the adjustment threshold of the evaporation pressure regulating valve can be adjusted according to the difference between the freezing point temperature and the preset temperature value to adjust the evaporation pressure in the pipeline where the evaporation pressure regulating valve is located, so that the evaporation temperature corresponding to the evaporation pressure is maintained above or near the freezing point. When the freezing point temperature is lower than the preset temperature value, the solenoid valve is controlled to open, so that the evaporation temperature is further reduced to achieve the desired lower evaporation temperature, while ensuring that the evaporation temperature is not too low, keeping it above or near the freezing point temperature. This prevents the evaporator heat exchange surface in the refrigeration system from freezing due to the evaporation temperature being too low, which would cause the refrigeration system to malfunction, thereby effectively ensuring the reliability of the refrigeration system operation. Attached Figure Description

[0028] Figure 1 This is a flowchart of a control method for a refrigeration system provided in Embodiment 1 of the present invention;

[0029] Figure 2 This is a flowchart of a control method for a refrigeration system provided in Embodiment 2 of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of a refrigeration system provided in Embodiment 2 of the present invention;

[0031] Figure 4 This is a structural block diagram of a control device for a refrigeration system provided in Embodiment 3 of the present invention. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0033] Example 1

[0034] Figure 1 This is a flowchart of a control method for a refrigeration system provided in Embodiment 1 of the present invention. This embodiment is applicable to controlling refrigeration systems, etc. The method can be executed by a control device of the refrigeration system, which can be implemented in software and / or hardware and can be integrated into the controller of the refrigeration system. The method specifically includes the following steps:

[0035] Step 110: Obtain the freezing point temperature of the refrigerant in the refrigeration system.

[0036] The freezing point temperature of the refrigerant can be collected by a freezing point acquisition device. The control device of the refrigeration system can be electrically connected to the freezing point acquisition device to obtain the freezing point temperature of the refrigerant. Alternatively, after the freezing point acquisition device collects the freezing point temperature of the refrigerant, the control device of the refrigeration system can receive the externally input freezing point temperature of the refrigerant.

[0037] Step 120: Determine the relationship between the freezing point temperature and the preset temperature value based on the freezing point temperature and the preset temperature value.

[0038] For example, the refrigerant in the refrigeration system is ethylene glycol or antifreeze, and the freezing point of the refrigerant is -35°C. The specific value of the preset temperature can be set according to the actual testing requirements of the refrigeration system, and is not limited here.

[0039] Step 130: Control the working status of the solenoid valve and evaporator pressure regulating valve in the refrigeration system according to their size relationship.

[0040] Specifically, when the freezing point temperature is higher than the preset temperature value, the adjustment threshold of the evaporation pressure regulating valve can be adjusted according to the difference between the freezing point temperature and the preset temperature value. This regulates the evaporation pressure in the pipeline where the evaporation pressure regulating valve is located, ensuring that the evaporation temperature corresponding to the evaporation pressure remains above the freezing point. When the freezing point temperature is lower than the preset temperature value, the solenoid valve is activated, further reducing the evaporation temperature to achieve the desired even lower evaporation temperature. Simultaneously, the evaporation temperature is kept above or near the freezing point to prevent the tiny channels on the heat exchange surface of the evaporator plate heat exchanger from freezing and malfunctioning due to the evaporation temperature of the refrigeration system falling below the freezing point. This effectively ensures reliable operation of the refrigeration system and reduces malfunctions.

[0041] The control method for the refrigeration system provided in this embodiment obtains the freezing point temperature of the refrigerant in the refrigeration system; determines the relationship between the freezing point temperature and a preset temperature value; and controls the operating state of the solenoid valve and the evaporation pressure regulating valve in the refrigeration system based on this relationship. Specifically, when the freezing point temperature is higher than the preset temperature value, the adjustment threshold of the evaporation pressure regulating valve can be adjusted based on the difference between the freezing point temperature and the preset temperature value to regulate the evaporation pressure in the pipeline where the evaporation pressure regulating valve is located, so that the evaporation temperature corresponding to the evaporation pressure is maintained above or near the freezing point. When the freezing point temperature is lower than the preset temperature value, the solenoid valve is activated to further reduce the evaporation temperature, achieving the desired even lower evaporation temperature while ensuring that the evaporation temperature is not too low, keeping it above or near the freezing point. This prevents the refrigeration system from malfunctioning due to the evaporation temperature being too low, thus effectively ensuring the reliability of the refrigeration system operation.

[0042] Example 2

[0043] Figure 2 This is a flowchart of a control method for a refrigeration system provided in Embodiment 2 of the present invention. This embodiment is applicable to controlling refrigeration systems, etc. The method can be executed by a control device of the refrigeration system, which can be implemented in software and / or hardware and can be integrated into the controller of the refrigeration system. The method specifically includes the following steps:

[0044] Step 210: Obtain the freezing point temperature of the refrigerant in the refrigeration system.

[0045] The freezing point temperature of the refrigerant can be collected by a freezing point acquisition device. The control device of the refrigeration system can be electrically connected to the freezing point acquisition device to obtain the freezing point temperature of the refrigerant. Alternatively, after the freezing point acquisition device collects the freezing point temperature of the refrigerant, the control device of the refrigeration system can receive the externally input freezing point temperature of the refrigerant.

[0046] Step 220: Determine the relationship between the freezing point temperature and the preset temperature value based on the freezing point temperature and the preset temperature value.

[0047] For example, the refrigerant in the refrigeration system is ethylene glycol or antifreeze, and the freezing point of the refrigerant is -35°C. The specific value of the preset temperature can be set according to the actual testing requirements of the refrigeration system, and is not limited here.

[0048] Step 230: According to the magnitude relationship, when the freezing point temperature is higher than the preset temperature value, and the difference between the freezing point temperature and the preset temperature value is within the preset first range, adjust the adjustment threshold of the evaporation pressure regulating valve to the preset first adjustment threshold.

[0049] The adjustment threshold is between 0-100%, meaning the adjustment threshold of the evaporator pressure regulating valve is between its minimum opening (0%) and maximum opening (100%). For example, the preset first range can be 0-20, and the preset first adjustment threshold is 50% of the maximum opening of the evaporator pressure regulating valve. If the freezing point temperature is -35℃ and the preset temperature value is -40℃, then the difference between the freezing point temperature and the preset temperature value is within the preset first range, and the adjustment threshold of the evaporator pressure regulating valve is 50% of its maximum opening. When adjusting the adjustment threshold of the evaporator pressure regulating valve, the control solenoid valve is in the closed state.

[0050] For example, Figure 3 This is a schematic diagram of a refrigeration system provided in Embodiment 2 of the present invention. (Reference) Figure 3 The refrigeration system includes a compressor 10, an evaporator 20, a condenser 30, an evaporation pressure regulating valve KVP, a solenoid valve SV, and a controller (not shown in the figure). The controller is electrically connected to the compressor 10, the evaporation pressure regulating valve KVP, and the solenoid valve SV. The compressor 10 is connected to the condenser 30, and the condenser 30 is connected to the evaporator 20. The evaporator 20 is connected to the compressor 10 through the evaporation pressure regulating valve KVP and the solenoid valve SV. The evaporation pressure regulating valve KVP and the solenoid valve SV are located in different branches. As described in any embodiment of the present invention, the control device of the refrigeration system is integrated into the controller. Specifically, the controller can control the working state of the evaporation pressure regulating valve KVP and the solenoid valve SV according to the relationship between the freezing point temperature and the preset temperature value.

[0051] And, as Figure 3 As shown, the evaporation pressure regulating valve KVP and the solenoid valve SV are both located near the outlet of the evaporator 20. By controlling the evaporation pressure regulating valve KVP and the solenoid valve SV located at the outlet of the evaporator 20, the evaporation temperature in the pipeline of the refrigeration system can be adjusted.

[0052] in addition, Figure 3 The evaporator 20 is connected to the water storage tank 40, and the top of the water storage tank 40 is connected to the bottom of the expansion tank 50. The water storage tank 40 is equipped with an electric heater, and the expansion tank 50 is equipped with a level gauge. The refrigerant flows to the water storage tank 40 through a pipe on the side of the water storage tank away from the evaporator 20, and is then transferred from the water storage tank 40 to the evaporator 20.

[0053] Step 240: When the freezing point temperature is higher than the preset temperature value, and the difference between the freezing point temperature and the preset temperature value is within the preset second range, adjust the adjustment threshold of the evaporation pressure regulating valve to the preset second adjustment threshold. The preset first range is smaller than the preset second range, and the preset first adjustment threshold is smaller than the preset second adjustment threshold.

[0054] For example, the preset second range can be 0-40, and the preset second adjustment threshold is 90% of the maximum opening of the evaporation pressure regulating valve. If the freezing point temperature is -5℃ and the preset temperature value is -40℃, then the difference between the freezing point temperature and the preset temperature value is within the preset second range, and the adjustment threshold of the evaporation pressure regulating valve is 90% of the maximum opening of the evaporation pressure regulating valve. When adjusting the adjustment threshold of the evaporation pressure regulating valve, the control solenoid valve is in the closed state.

[0055] Step 250: When the freezing point temperature is lower than the preset temperature value, control the solenoid valve to open.

[0056] Specifically, if the freezing point temperature is lower than the preset temperature value, it means that the freezing point temperature is too low and there is no need for the evaporation pressure regulating valve to protect it. The evaporation pressure regulating valve can be controlled to be closed, and the solenoid valve can be controlled to conduct, so that the evaporation temperature is further reduced to achieve the purpose of lowering the actual required evaporation temperature. At the same time, it ensures that the evaporation temperature is not too low, so that the evaporation temperature is above or near the freezing point temperature, effectively ensuring the reliable operation of the refrigeration system.

[0057] The control method for the refrigeration system provided in this embodiment controls the working state of the solenoid valve and the evaporation pressure regulating valve in the refrigeration system according to the relationship between the freezing point temperature and the preset temperature value. For example, when the freezing point temperature is higher than the preset temperature value, the adjustment threshold of the evaporation pressure regulating valve can be adjusted according to the difference between the freezing point temperature and the preset temperature value to adjust the evaporation pressure in the pipeline where the evaporation pressure regulating valve is located, so that the evaporation temperature corresponding to the evaporation pressure is kept above the freezing point. When the freezing point temperature is lower than the preset temperature value, the solenoid valve is controlled to open, so that the evaporation temperature is further reduced to achieve the purpose of lowering the actual required evaporation temperature, while ensuring that the evaporation temperature is not too low, so that the evaporation temperature is above or near the freezing point temperature, preventing the refrigeration system from failing to work properly due to the evaporation temperature of the refrigeration system being too low, thereby effectively ensuring the reliability of the refrigeration system operation.

[0058] Example 3

[0059] Figure 4 This is a structural block diagram of a control device for a refrigeration system provided in Embodiment 3 of the present invention. (Reference) Figure 4The control device of the refrigeration system includes: a temperature acquisition module 310, a magnitude determination module 320, and a status control module 330; wherein, the temperature acquisition module 310 is used to acquire the freezing point temperature of the refrigerant in the refrigeration system; the magnitude determination module 320 is used to determine the magnitude relationship between the freezing point temperature and the preset temperature value based on the freezing point temperature and the preset temperature value; and the status control module 330 is used to control the working status of the solenoid valve and the evaporation pressure regulating valve in the refrigeration system based on the magnitude relationship.

[0060] Optionally, the state control module 330 includes a threshold adjustment unit and a state control unit; wherein, the threshold adjustment unit is used to adjust the adjustment threshold of the evaporation pressure regulating valve when the freezing point temperature is higher than the preset temperature value; and the state control unit is used to control the solenoid valve to open when the freezing point temperature is lower than the preset temperature value.

[0061] Preferably, the threshold adjustment unit includes a first adjustment subunit and a second adjustment subunit; wherein, the first adjustment subunit is used to adjust the adjustment threshold of the evaporation pressure regulating valve to a preset first adjustment threshold when the freezing point temperature is higher than a preset temperature value and the difference between the freezing point temperature and the preset temperature value is within a preset first range; the second adjustment subunit is used to adjust the adjustment threshold of the evaporation pressure regulating valve to a preset second adjustment threshold when the freezing point temperature is higher than the preset temperature value and the difference between the freezing point temperature and the preset temperature value is within a preset second range, wherein the preset first range is smaller than the preset second range and the preset first adjustment threshold is smaller than the preset second adjustment threshold.

[0062] Optionally, the control device of the above-mentioned refrigeration system further includes a solenoid valve control module, which is used by the threshold adjustment unit in the state control module 330 to control the solenoid valve to be in a closed state when adjusting the adjustment threshold of the evaporating pressure regulating valve.

[0063] Optionally, the control device of the above-mentioned refrigeration system further includes a regulating valve control module, which is used by the state control unit in the state control module 330 to control the evaporating pressure regulating valve to be in the closed state when the solenoid valve is turned on.

[0064] The control device for the refrigeration system provided in this embodiment belongs to the same inventive concept as the control method for the refrigeration system provided in any embodiment of the present invention, and has corresponding beneficial effects. For technical details not covered in this embodiment, please refer to the control method for the refrigeration system provided in any embodiment of the present invention.

[0065] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A control method for a refrigeration system, characterized in that, The refrigeration system includes a compressor, an evaporator, a condenser, an evaporating pressure regulating valve, a solenoid valve, and a controller. The controller is electrically connected to the compressor, the evaporating pressure regulating valve, and the solenoid valve. The compressor is connected to the condenser, and the condenser is connected to the evaporator. The evaporator is connected to the compressor via the evaporating pressure regulating valve and the solenoid valve. The evaporating pressure regulating valve and the solenoid valve are located on different branches and are both positioned near the outlet of the evaporator. The control method is executed by the controller and includes: Obtain the freezing point temperature of the refrigerant in the refrigeration system; Based on the freezing point temperature and the preset temperature value, determine the relationship between the freezing point temperature and the preset temperature value; When the freezing point temperature is higher than the preset temperature value, the adjustment threshold of the evaporation pressure regulating valve is adjusted.

2. The control method according to claim 1, characterized in that, The step of adjusting the adjustment threshold of the evaporation pressure regulating valve when the freezing point temperature is higher than the preset temperature value includes: When the freezing point temperature is higher than the preset temperature value, and the difference between the freezing point temperature and the preset temperature value is within a preset first range, the adjustment threshold of the evaporation pressure regulating valve is the preset first adjustment threshold. When the freezing point temperature is higher than the preset temperature value, and the difference between the freezing point temperature and the preset temperature value is within a preset second range, the adjustment threshold of the evaporation pressure regulating valve is the preset second adjustment threshold.

3. The control method according to claim 2, characterized in that, The preset first range is smaller than the preset second range, and the preset first adjustment threshold is smaller than the preset second adjustment threshold.

4. The control method according to claim 2, characterized in that, Also includes: When adjusting the adjustment threshold of the evaporation pressure regulating valve, the solenoid valve is controlled to be in the closed state.

5. The control method according to claim 2, characterized in that, The adjustment threshold is between 0 and 100%.

6. A control device for a refrigeration system, characterized in that, The refrigeration system includes a compressor, an evaporator, a condenser, an evaporating pressure regulating valve, a solenoid valve, and a controller. The controller is electrically connected to the compressor, the evaporating pressure regulating valve, and the solenoid valve. The compressor is connected to the condenser, and the condenser is connected to the evaporator. The evaporator is connected to the compressor via the evaporating pressure regulating valve and the solenoid valve. The evaporating pressure regulating valve and the solenoid valve are located on different branches and are both positioned near the outlet of the evaporator. The control device is integrated into the controller and includes: A temperature acquisition module is used to acquire the freezing point temperature of the refrigerant in the refrigeration system; The size determination module is used to determine the size relationship between the freezing point temperature and the preset temperature value based on the freezing point temperature and the preset temperature value. The status control module includes a threshold adjustment unit, which is used to adjust the adjustment threshold of the evaporation pressure regulating valve when the freezing point temperature is higher than the preset temperature value.

7. The control device according to claim 6, characterized in that, The threshold adjustment unit includes: The first regulating subunit is used to adjust the regulating threshold of the evaporation pressure regulating valve to a preset first regulating threshold when the freezing point temperature is higher than the preset temperature value and the difference between the freezing point temperature and the preset temperature value is within a preset first range. The second adjustment subunit is used to adjust the adjustment threshold of the evaporation pressure regulating valve to a preset second adjustment threshold when the freezing point temperature is higher than the preset temperature value and the difference between the freezing point temperature and the preset temperature value is within a preset second range.

8. The control device according to claim 7, characterized in that, The preset first range is smaller than the preset second range, and the preset first adjustment threshold is smaller than the preset second adjustment threshold.

9. The control device according to claim 6, characterized in that, Also includes: The solenoid valve control module is used to control the solenoid valve to be in a closed state when the threshold adjustment unit adjusts the adjustment threshold of the evaporation pressure regulating valve.

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