A method, apparatus and system for controlling subcooling

Abstract

The embodiment of the present application discloses a supercooling degree control method, device and system. The supercooling degree includes at least one of the supercooling degree of the condenser outlet and the supercooling degree of the expansion valve inlet. The inlet of the condenser is communicated with the compressor, the outlet of the condenser is communicated with the evaporator, the expansion valve and the electromagnetic valve are arranged in the communication pipeline of the condenser and the evaporator, the condensing fan is arranged near the condenser, the control method comprises: obtaining the current temperature and pressure of the condenser outlet and the current temperature and pressure of the expansion valve inlet; determining the current supercooling degree of the condenser outlet according to the current temperature and pressure of the condenser outlet, and determining the current supercooling degree of the expansion valve inlet according to the current temperature and pressure of the expansion valve inlet; and controlling the working state of the condensing fan, the expansion valve and the electromagnetic valve according to the current supercooling degree of the condenser outlet and the current supercooling degree of the expansion valve inlet. The supercooling degree control method, device and system provided by the embodiment of the present application can improve the control reliability.

Description

Technical Field

[0001] The present invention relates to subcooling control technology, and more particularly to a subcooling control method, apparatus and system. Background Technology

[0002] Subcooling, such as the subcooling at the condenser outlet, is the difference between the saturation temperature corresponding to the refrigerant pressure at a certain point at the condenser outlet and the actual temperature of the refrigerant. Insufficient subcooling will affect the evaporator's refrigeration efficiency, while excessive subcooling will affect thermal economy. Therefore, reliable control of subcooling is necessary.

[0003] Currently, existing methods for controlling subcooling typically involve designing the condenser into condensing and subcooling sections. This results in a narrow adjustment range for subcooling, poor adjustment accuracy, and reduced control reliability. Summary of the Invention

[0004] This invention provides a method, apparatus, and system for controlling subcooling to improve control reliability.

[0005] In a first aspect, embodiments of the present invention provide a subcooling control method, wherein the subcooling includes at least one of the subcooling at the condenser outlet and the subcooling at the expansion valve inlet, the condenser inlet is connected to a compressor, the condenser outlet is connected to an evaporator, an expansion valve and a solenoid valve are provided in the connecting pipeline between the condenser and the evaporator, the solenoid valve is located on the side of the expansion valve closer to the evaporator, and a condensing fan is provided near the condenser, the subcooling control method comprising:

[0006] Obtain the current temperature and pressure at the condenser outlet, and the current temperature and pressure at the expansion valve inlet;

[0007] The current subcooling of the condenser outlet is determined based on the current temperature and pressure at the condenser outlet, and the current subcooling of the expansion valve inlet is determined based on the current temperature and pressure at the expansion valve inlet.

[0008] The operating states of the condenser fan, the expansion valve, and the solenoid valve are controlled based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet, so as to adjust the subcooling at the condenser outlet and the subcooling at the expansion valve inlet.

[0009] Optionally, the condenser includes a first condenser and a second condenser, and the condensing fan includes a first condensing fan and a second condensing fan. The first condensing fan is close to the first condenser, and the second condensing fan is close to the second condenser. The inlet of the first condenser is connected to the compressor, the outlet of the first condenser is connected to the inlet of the liquid storage tank, the outlet of the liquid storage tank is connected to the inlet of the second condenser, and the outlet of the second condenser is connected to the inlet of the evaporator.

[0010] The step of controlling the operating states of the condenser fan, the expansion valve, and the solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet includes:

[0011] The operating state of the first condenser fan is controlled according to the current subcooling at the outlet of the first condenser in order to adjust the subcooling at the outlet of the first condenser.

[0012] Based on the current subcooling at the inlet of the expansion valve, the operating states of the second condensing fan, the expansion valve, and the solenoid valve are controlled to adjust the subcooling at the inlet of the expansion valve.

[0013] Optionally, controlling the operating states of the second condensing fan, the expansion valve, and the solenoid valve based on the current subcooling at the expansion valve inlet includes:

[0014] When the current subcooling at the inlet of the expansion valve is within a preset small subcooling range, the wind speed of the second condenser fan is adjusted to control the difference between the current subcooling at the inlet of the expansion valve and the preset first subcooling within a preset first range.

[0015] When the current subcooling at the inlet of the expansion valve is in the preset intermediate subcooling range, the on / off time of the solenoid valve is adjusted to control the difference between the current subcooling at the inlet of the expansion valve and the preset second subcooling within the preset second range.

[0016] When the current subcooling at the inlet of the expansion valve is in the preset large subcooling range, the opening of the expansion valve is adjusted to control the difference between the current subcooling at the inlet of the expansion valve and the preset third subcooling within the preset third range.

[0017] Optionally, the outlet of the second condenser is connected to the inlet of the evaporator via a spiral economizer, and the solenoid valve and the expansion valve are located in the pipeline branch connecting the spiral economizer and the inlet of the evaporator;

[0018] The step of controlling the operating states of the condenser fan, the expansion valve, and the solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet includes:

[0019] When the current subcooling degree at the inlet of the expansion valve is within a preset small subcooling degree range, the expansion valve and the solenoid valve are controlled to be in the closed state.

[0020] When the current subcooling degree at the inlet of the expansion valve is in the preset medium subcooling degree range or the preset large subcooling degree range, the expansion valve and the solenoid valve are controlled to be in operation.

[0021] Optionally, controlling the operating states of the condenser fan, the expansion valve, and the solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet includes:

[0022] When the current subcooling degree at the inlet of the expansion valve is in the preset medium subcooling degree range or the preset large subcooling degree range, the solenoid valve is controlled to be in 100% output operation state.

[0023] Optionally, controlling the operating states of the condenser fan, the expansion valve, and the solenoid valve includes:

[0024] The working status of the condenser fan, the solenoid valve, and the expansion valve is controlled by PID regulation.

[0025] Secondly, embodiments of the present invention provide a subcooling control device, wherein the subcooling includes at least one of the subcooling at the condenser outlet and the subcooling at the expansion valve inlet, the condenser inlet is connected to a compressor, the condenser outlet is connected to an evaporator, an expansion valve and a solenoid valve are provided in the connecting pipeline between the condenser and the evaporator, the solenoid valve is located on the side of the expansion valve closer to the evaporator, and a condensing fan is provided near the condenser. The subcooling control device includes:

[0026] The data acquisition module is used to acquire the current temperature and pressure at the outlet of the condenser and the current temperature and pressure at the inlet of the expansion valve.

[0027] The subcooling determination module is used to determine the current subcooling of the condenser outlet based on the current temperature and pressure of the condenser outlet, and to determine the current subcooling of the expansion valve inlet based on the current temperature and pressure of the expansion valve inlet.

[0028] The status control module is used to control the operating status of the condenser fan, the expansion valve and the solenoid valve according to the current subcooling of the condenser outlet and the current subcooling of the expansion valve inlet, so as to adjust the subcooling of the condenser outlet and the subcooling of the expansion valve inlet.

[0029] Thirdly, embodiments of the present invention provide a subcooling control system, comprising: a compressor, a condenser, a condensing fan, an evaporator, a solenoid valve, an expansion valve, and a controller; the inlet of the condenser is connected to the outlet of the compressor, the outlet of the condenser is connected to the inlet of the evaporator, the outlet of the evaporator is connected to the inlet of the compressor, the expansion valve and the solenoid valve are located in the connecting pipeline between the condenser and the evaporator, the solenoid valve is located on the side of the expansion valve closer to the evaporator, and the condensing fan is close to the condenser; the compressor, the condensing fan, the solenoid valve, and the expansion valve are all electrically connected to the controller, and the subcooling control device as described in the second aspect is integrated into the controller.

[0030] Optionally, the condenser includes a first condenser and a second condenser, and the condensing fan includes a first condensing fan and a second condensing fan. The first condensing fan is close to the first condenser, and the second condensing fan is close to the second condenser. The inlet of the first condenser is connected to the outlet of the compressor, the outlet of the first condenser is connected to the inlet of the liquid storage tank, the outlet of the liquid storage tank is connected to the inlet of the second condenser, and the outlet of the second condenser is connected to the inlet of the evaporator.

[0031] Optionally, the subcooling control system further includes a spiral economizer, a temperature sensor, and a pressure sensor. The outlet of the second condenser is connected to the inlet of the evaporator through the spiral economizer. The outlet of the second condenser is also connected to the inlet of the compressor through the spiral economizer. The temperature sensor and the pressure sensor are provided at the outlet of the first condenser and on the side of the expansion valve near the evaporator.

[0032] The subcooling control method, apparatus, and system provided in this invention embodiment include at least one of the subcooling at the condenser outlet and the subcooling at the expansion valve inlet. The condenser inlet is connected to the compressor, and the condenser outlet is connected to the evaporator. An expansion valve and a solenoid valve are installed in the connecting pipeline between the condenser and the evaporator. The solenoid valve is located on the side of the expansion valve closer to the evaporator. A condensing fan is installed near the condenser. The subcooling control method includes: acquiring the current temperature and pressure at the condenser outlet and the current temperature and pressure at the expansion valve inlet; determining the current subcooling at the condenser outlet based on the current temperature and pressure at the condenser outlet, and determining the current subcooling at the expansion valve inlet based on the current temperature and pressure at the expansion valve inlet; and controlling the operating states of the condensing fan, the expansion valve, and the solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet to adjust the subcooling at the condenser outlet and the expansion valve inlet. The subcooling control method, apparatus, and system provided in this invention control the operating states of the condenser fan, expansion valve, and solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet. This includes adjusting the condenser fan speed, the expansion valve opening degree, and the solenoid valve on / off time. Compared to existing methods that only adjust the subcooling at the condenser outlet, this method effectively regulates both the subcooling at the condenser outlet and the subcooling at the expansion valve inlet by controlling the operating states of the condenser fan, expansion valve, and solenoid valve. This solves the problem in the prior art where adjusting only the subcooling at the condenser outlet affects the reliability of subcooling control, thereby improving the reliability of subcooling control. Attached Figure Description

[0033] Figure 1 This is a flowchart of a subcooling control method provided in Embodiment 1 of the present invention;

[0034] Figure 2 This is a flowchart of a subcooling control method provided in Embodiment 2 of the present invention;

[0035] Figure 3 This is a structural block diagram of a subcooling control device provided in Embodiment 3 of the present invention;

[0036] Figure 4 This is a schematic diagram of a subcooling control system provided in Embodiment 4 of the present invention. Detailed Implementation

[0037] 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.

[0038] Example 1

[0039] Figure 1 This is a flowchart of a subcooling control method provided in Embodiment 1 of the present invention. This embodiment can be applied to controlling subcooling, etc. Subcooling includes at least one of the subcooling at the condenser outlet and the subcooling at the expansion valve inlet. The condenser inlet is connected to the compressor, and the condenser outlet is connected to the evaporator. An expansion valve and a solenoid valve are installed in the connecting pipeline between the condenser and the evaporator. The solenoid valve is located on the side of the expansion valve closer to the evaporator. A condenser fan is installed near the condenser. This method can be executed by a subcooling control device, which can be integrated into the controller of the subcooling control system. The controller can be implemented in software and / or hardware. The method specifically includes the following steps:

[0040] Step 110: Obtain the current temperature and pressure at the condenser outlet and the current temperature and pressure at the expansion valve inlet.

[0041] Specifically, pressure sensors and temperature sensors can be installed at the outlet of the condenser and the inlet of the expansion valve (the fluid in the pipeline where the expansion valve is located flows through the expansion valve first through the inlet of the expansion valve and then through the outlet of the expansion valve during its journey to the evaporator). The pressure sensor and the temperature sensor respectively collect the current pressure and current temperature of the corresponding device. The subcooling control device can be electrically connected to the pressure sensor and the temperature sensor to obtain the current temperature and pressure at the outlet of the condenser and the current temperature and pressure at the inlet of the expansion valve.

[0042] Step 120: Determine the current subcooling of the condenser outlet based on the current temperature and pressure at the condenser outlet, and determine the current subcooling of the expansion valve inlet based on the current temperature and pressure at the expansion valve inlet.

[0043] Specifically, the current subcooling at the condenser outlet is the current subcooling at the condenser outlet, and the current subcooling at the expansion valve inlet is the current subcooling on the side of the expansion valve furthest from the condenser. The process of determining the subcooling based on temperature and pressure can refer to existing subcooling determination processes, and will not be elaborated here.

[0044] Step 130: Based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet, control the operating status of the condenser fan, expansion valve, and solenoid valve to adjust the subcooling at the condenser outlet and the subcooling at the expansion valve inlet.

[0045] Specifically, the operating status of the condenser fan, solenoid valve, and expansion valve is controlled by PID regulation. If the current subcooling at the condenser outlet decreases, the condenser fan speed can be increased, and the solenoid valve and expansion valve remain closed. If the current subcooling at the condenser outlet increases, the condenser fan speed can be decreased, and the solenoid valve and expansion valve remain open, so that the subcooling at the condenser outlet and the subcooling at the expansion valve inlet are close to their respective target subcooling.

[0046] It should be noted that the specific duration of the above preset time can be determined according to actual control needs, and is not limited here.

[0047] The subcooling control method provided in this embodiment includes at least one of the subcooling at the condenser outlet and the subcooling at the expansion valve inlet. The condenser inlet is connected to the compressor, and the condenser outlet is connected to the evaporator. An expansion valve and a solenoid valve are installed in the connecting pipeline between the condenser and the evaporator. The solenoid valve is located on the side of the expansion valve closer to the evaporator. A condensing fan is installed near the condenser. The subcooling control method includes: acquiring the current temperature and pressure at the condenser outlet and the current temperature and pressure at the expansion valve inlet; determining the current subcooling at the condenser outlet based on the current temperature and pressure at the condenser outlet, and determining the current subcooling at the expansion valve inlet based on the current temperature and pressure at the expansion valve inlet; and controlling the operating states of the condensing fan, the expansion valve, and the solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet to adjust the subcooling at the condenser outlet and the subcooling at the expansion valve inlet. The subcooling control method provided in this embodiment controls the operating states of the condenser fan, expansion valve, and solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet. This includes adjusting the fan speed, the opening degree of the expansion valve, and the on / off time of the solenoid valve. Compared with existing methods that only adjust the subcooling at the condenser outlet, this method effectively regulates both the subcooling at the condenser outlet and the subcooling at the expansion valve inlet by controlling the operating states of the condenser fan, expansion valve, and solenoid valve. This solves the problem in existing technologies where adjusting only the subcooling at the condenser outlet affects the reliability of subcooling control, thereby improving the reliability of subcooling control.

[0048] Example 2

[0049] Figure 2 This is a flowchart of a subcooling control method provided in Embodiment 2 of the present invention. This embodiment can be applied to controlling subcooling, etc. Subcooling includes at least one of the subcooling at the condenser outlet and the subcooling at the expansion valve inlet. The condenser inlet is connected to the compressor, and the condenser outlet is connected to the evaporator. An expansion valve and a solenoid valve are installed in the connecting pipeline between the condenser and the evaporator. The solenoid valve is located on the side of the expansion valve closer to the evaporator. A condenser fan is installed near the condenser. This method can be executed by a subcooling control device, which can be integrated into the controller of the subcooling control system. The controller can be implemented in software and / or hardware. The method specifically includes the following steps:

[0050] Step 210: Obtain the current temperature and pressure at the condenser outlet and the current temperature and pressure at the expansion valve inlet.

[0051] Specifically, pressure and temperature sensors can be installed at the outlet of the condenser and on the side of the expansion valve away from the condenser. The pressure and temperature sensors collect the current pressure and temperature of the corresponding devices, respectively. The subcooling control device can be electrically connected to the pressure and temperature sensors to obtain the current temperature and pressure at the condenser outlet and the current temperature and pressure at the expansion valve inlet.

[0052] Step 220: Determine the current subcooling of the condenser outlet based on the current temperature and pressure at the condenser outlet, and determine the current subcooling of the expansion valve inlet based on the current temperature and pressure at the expansion valve inlet.

[0053] For example, the condenser includes a first condenser and a second condenser, and the condensing fan includes a first condensing fan and a second condensing fan. The first condensing fan is located near the first condenser, and the second condensing fan is located near the second condenser. The inlet of the first condenser is connected to the compressor, the outlet of the first condenser is connected to the inlet of the liquid receiver, the outlet of the liquid receiver is connected to the inlet of the second condenser, and the outlet of the second condenser is connected to the inlet of the evaporator. The outlet of the second condenser is connected to the inlet of the evaporator via a spiral economizer. The solenoid valve and expansion valve are located in the branch pipe connecting the spiral economizer and the inlet of the evaporator. Specifically, the current subcooling of the first condenser outlet is determined based on the current temperature and pressure of the first condenser outlet. The process of determining the subcooling based on temperature and pressure can refer to existing subcooling determination processes and will not be elaborated here.

[0054] Step 230: Control the operating state of the first condenser fan according to the current subcooling at the outlet of the first condenser, so as to adjust the subcooling at the outlet of the first condenser.

[0055] Specifically, the speed of the first condenser fan is controlled according to the current subcooling at the outlet of the first condenser. For example, if the current subcooling at the outlet of the first condenser decreases, the speed of the first condenser fan is increased to adjust the subcooling at the outlet of the first condenser.

[0056] Step 240: When the current subcooling at the expansion valve inlet is in the preset small subcooling range, control the expansion valve and solenoid valve to be in the closed state, and adjust the wind speed of the second condenser fan to control the difference between the current subcooling at the expansion valve inlet and the preset first subcooling within the preset first range.

[0057] The current subcooling at the expansion valve inlet is the current subcooling on the side of the expansion valve furthest from the second condenser, and the preset first subcooling is the target subcooling corresponding to the current subcooling being within a preset small subcooling range. By controlling the expansion valve and solenoid valve to be in the closed state and adjusting the airflow speed of the second condenser fan to increase, the difference between the current subcooling at the expansion valve inlet and the preset first subcooling is made to be within a preset first range.

[0058] Step 250: When the current subcooling at the expansion valve inlet is in the preset subcooling range, control the expansion valve and solenoid valve to be in operation so as to control the difference between the current subcooling at the expansion valve inlet and the preset second subcooling within the preset second range.

[0059] The solenoid valve is in 100% output operation mode, meaning it is always in the on state. The preset second subcooling degree is the target subcooling degree corresponding to the current subcooling degree being in the preset subcooling degree range. Within this subcooling degree range, the expansion valve and the solenoid valve are controlled to be in operation and the opening degree of the solenoid valve is adjusted so that the difference between the current subcooling degree at the expansion valve inlet and the preset second subcooling degree is within the preset second range.

[0060] Step 260: When the current subcooling at the expansion valve inlet is in the preset large subcooling range, control the expansion valve and solenoid valve to be in operation, and adjust the opening of the expansion valve to control the difference between the current subcooling at the expansion valve inlet and the preset third subcooling to be within the preset third range.

[0061] The solenoid valve is operating at 100% output. Specifically, the opening of the expansion valve can be adjusted using PID control, and the fan speed and on / off time of the solenoid valve can also be adjusted using PID control when controlling the operation of the condenser fan and the solenoid valve.

[0062] It should be noted that the specific values ​​of each preset subcooling segment, each preset range, and each preset subcooling in this embodiment can be determined according to actual control requirements, and are not limited here.

[0063] The condenser inlet subcooling control method provided in this embodiment controls the working state of the first condenser fan based on the current subcooling at the first condenser outlet, and controls the working state of the second condenser fan, expansion valve, and solenoid valve based on the current subcooling at the expansion valve inlet. This includes adjusting the fan speed of the second condenser fan, the opening degree of the expansion valve, and the on / off time of the solenoid valve. Compared with the existing method that only adjusts the subcooling at the condenser outlet, this method effectively regulates both the subcooling at the condenser outlet and the subcooling at the expansion valve inlet by controlling the working state of each condenser fan, expansion valve, and solenoid valve. This solves the problem in the prior art where adjusting only the subcooling at the condenser outlet affects the reliability of subcooling control, thereby improving the reliability of subcooling control.

[0064] Example 3

[0065] Figure 3This is a structural block diagram of a subcooling control device provided in Embodiment 3 of the present invention. The subcooling includes at least one of the subcooling at the condenser outlet and the subcooling at the expansion valve inlet. The condenser inlet is connected to the compressor, and the condenser outlet is connected to the evaporator. An expansion valve and a solenoid valve are installed in the connecting pipe between the condenser and the evaporator. The solenoid valve is located on the side of the expansion valve closer to the evaporator. A condensing fan is installed near the condenser. The subcooling control device includes: a data acquisition module 310, a subcooling determination module 320, and a status control module 330. The data acquisition module 310 is used to acquire the current temperature and pressure at the condenser outlet and the current temperature and pressure at the expansion valve inlet. The subcooling determination module 320 is used to determine the current subcooling at the condenser outlet based on the current temperature and pressure at the condenser outlet, and to determine the current subcooling at the expansion valve inlet based on the current temperature and pressure at the expansion valve inlet. The status control module 330 is used to control the operating status of the condensing fan, the expansion valve, and the solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet, so as to adjust the subcooling at the condenser outlet and the subcooling at the expansion valve inlet.

[0066] Based on the above embodiments, the condenser includes a first condenser and a second condenser, and the condensing fan includes a first condensing fan and a second condensing fan. The first condensing fan is close to the first condenser, and the second condensing fan is close to the second condenser. The inlet of the first condenser is connected to the compressor, the outlet of the first condenser is connected to the inlet of the liquid storage tank, the outlet of the liquid storage tank is connected to the inlet of the second condenser, and the outlet of the second condenser is connected to the inlet of the evaporator. The state control module 330 includes a first regulating unit and a second regulating unit. The first regulating unit is used to control the working state of the first condensing fan according to the current subcooling of the first condenser outlet to regulate the subcooling of the first condenser outlet. The second regulating unit is used to control the working state of the second condensing fan, the expansion valve, and the solenoid valve according to the current subcooling of the expansion valve inlet to regulate the subcooling of the expansion valve inlet.

[0067] In one embodiment, the state control module 330 includes: a third adjustment unit, a fourth adjustment unit, and a fifth adjustment unit; wherein, the third adjustment unit is used to adjust the wind speed of the second condenser fan when the current subcooling degree at the expansion valve inlet is in a preset small subcooling degree range, so as to control the difference between the current subcooling degree at the expansion valve inlet and the preset first subcooling degree within a preset first range; the fourth adjustment unit is used to adjust the on / off time of the solenoid valve when the current subcooling degree at the expansion valve inlet is in a preset medium subcooling degree range, so as to control the difference between the current subcooling degree at the expansion valve inlet and the preset second subcooling degree within a preset second range; the fifth adjustment unit is used to adjust the opening degree of the expansion valve when the current subcooling degree at the expansion valve inlet is in a preset large subcooling degree range, so as to control the difference between the current subcooling degree at the expansion valve inlet and the preset third subcooling degree within a preset third range.

[0068] Preferably, the outlet of the second condenser is connected to the inlet of the evaporator via a spiral economizer, and the solenoid valve and expansion valve are located in the branch pipe connecting the inlet of the spiral economizer and the inlet of the evaporator; the state control module 330 includes: a sixth regulating unit and a seventh regulating unit; wherein, the sixth regulating unit is used to control the expansion valve and the solenoid valve to be in the closed state when the current subcooling degree at the inlet of the expansion valve is in the preset small subcooling degree range; the seventh regulating unit is used to control the expansion valve and the solenoid valve to be in the operating state when the current subcooling degree at the inlet of the expansion valve is in the preset medium subcooling degree range or the preset large subcooling degree range.

[0069] Preferably, the state control module 330 includes: an eighth adjustment unit; the eighth adjustment unit is used to control the solenoid valve to be in 100% output operation state when the current subcooling degree at the expansion valve inlet is in a preset medium subcooling degree range or a preset large subcooling degree range.

[0070] Preferably, the state control module 330 includes: a ninth adjustment unit; the ninth adjustment unit is used to control the working state of the condenser fan, solenoid valve and expansion valve through PID adjustment.

[0071] The subcooling control device provided in this embodiment belongs to the same inventive concept as the subcooling control method 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 subcooling control method provided in any embodiment of the present invention.

[0072] Example 4

[0073] Figure 4 This is a schematic diagram of a subcooling control system provided in Embodiment 4 of the present invention. (Reference) Figure 4 The subcooling control system includes: a compressor CM, a condenser COND, a condenser fan FD, an evaporator EVAP, a solenoid valve HSV, an expansion valve EEV2, and a controller (not shown in the figure); the inlet of the condenser COND is connected to the outlet of the compressor CM, the outlet of the condenser COND is connected to the inlet of the evaporator EVAP, the outlet of the evaporator EVAP is connected to the inlet of the compressor CM, the expansion valve EEV2 and the solenoid valve HSV are located in the connecting pipe between the condenser COND and the evaporator EVAP, the solenoid valve HSV is located on the side of the expansion valve EEV2 closer to the evaporator COND, and the condenser fan FD is close to the condenser COND; the compressor CM, the condenser fan FD, the solenoid valve HSV, and the expansion valve EEV2 are all electrically connected to the controller, and the subcooling control device as described in any embodiment of the present invention is integrated into the controller.

[0074] The system comprises two main components: an expansion valve (EEV2) and a solenoid valve (HSV). The compressor (CM) is a variable frequency compressor, the core of the system's power system. It compresses the intake of low-temperature, low-pressure refrigerant vapor into high-pressure, high-temperature superheated vapor, creating conditions for condensation at a higher temperature. This compressor then transports and propels the refrigerant within the system, completing the refrigeration cycle and achieving cooling through heat-work conversion. The variable frequency compressor (CM) can quickly respond to varying heat outputs and response time requirements, ensuring the system reaches the desired operating state and boundary conditions quickly, while also offering energy savings. An evaporator fan (FD3) is located on the evaporator EVAP side. The evaporator EVAP evaporates the low-pressure, low-temperature gas-liquid mixture of refrigerant, throttled by the expansion valve, into a low-pressure, medium-temperature gas. Evaporation is an endothermic process; the evaporator is a device that evaporates liquid refrigerant into gas. The evaporator fan (FD3) transfers the cooled refrigerant from the evaporator EVAP into the air. A pulse solenoid valve is a type of solenoid valve used to perform rapid cyclic cycles within a short period of time to maintain a very close temperature, thereby regulating the refrigerant flow rate while keeping the pressure essentially constant. The specific process of the controller controlling the subcooling can be found in any of the above embodiments and will not be repeated here.

[0075] refer to Figure 4 Optionally, the condenser COND includes a first condenser COND1 and a second condenser COND2, and the condenser fan FD includes a first condenser fan FD1 and a second condenser fan FD2. The first condenser fan FD1 is close to the first condenser COND1, and the second condenser fan FD2 is close to the second condenser COND2. The inlet of the first condenser COND1 is connected to the outlet of the compressor CM, the outlet of the first condenser COND1 is connected to the inlet of the liquid receiver tank, the outlet of the liquid receiver tank LR is connected to the inlet of the second condenser COND2, and the outlet of the second condenser COND2 is connected to the inlet of the evaporator EVAP.

[0076] The first condenser COND1 condenses the high-pressure, high-temperature refrigerant gas delivered by the compressor into a high-pressure, high-temperature liquid. The condensation process is a heat dissipation process; the condenser is a device that condenses refrigerant vapor into refrigerant liquid. The first condensing fan FD1 transfers the heat dissipated by the refrigerant in the first condenser COND1 to the air, maintaining the condensing temperature and pressure within a reasonable range. After condensation in the first condenser COND1, the refrigerant undergoes secondary cooling by the second condenser COND2 and the second condensing fan FD2, bringing it to a subcooled state. The liquid receiver LR stores the liquid component of the refrigerant, reducing the load on the condenser and adapting to changes in supply demand due to load variations. When the evaporation load increases, the supply also increases, replenished by the liquid stored in the liquid receiver LR; when the load decreases, the required liquid volume also decreases, and excess liquid is stored in the liquid receiver LR.

[0077] refer to Figure 4 Optionally, the subcooling control system also includes a spiral economizer EC, a temperature sensor, and a pressure sensor. The outlet of the second condenser COND2 is connected to the inlet of the evaporator through the spiral economizer EC. The outlet of the second condenser COND2 is also connected to the inlet of the compressor CM through the spiral economizer EC. Temperature sensors and pressure sensors are installed at the outlet of the first condenser COND1 and on the side of the expansion valve EEV2 near the evaporator EVAP.

[0078] Specifically, in the branch circuit branching off from the outlet of the spiral economizer EC, the refrigerant flows through the pulse solenoid valve HSV and the subcooled electronic expansion valve EEV2 to form a low-temperature two-phase refrigerant, deeply cooling the main circuit of the spiral economizer EC, thus achieving a greater subcooling of the main circuit refrigerant. Furthermore, the outlet of the first condenser COND1 is equipped with a temperature sensor TT1 and a pressure sensor TP1 (and also a first refrigerant charging valve TV1). On the side of the expansion valve EEV2 near the evaporator EVAP, a temperature sensor TT2 and a pressure sensor TP2 (and also a second refrigerant charging valve TV2) are installed. The pressure sensor is used to measure the system's operating pressure in real time; by monitoring the pressure, it can be ensured that the system operates within the specified requirements. The temperature sensor is used to measure the system's operating temperature in real time; by monitoring the temperature, it can be ensured that the system operates within the specified requirements. The main circuit connecting the evaporator EVAP and the spiral economizer EC is equipped with a main circuit electronic expansion valve EEV1 and a solenoid valve SV. The solenoid valve SV controls refrigerant flow based on energization. When de-energized, it restricts refrigerant flow (normally closed), and when the valve coil is energized, it allows refrigerant flow. The electronic expansion valve controls the injection of liquid refrigerant from the condenser into the evaporator. As the refrigerant passes through the electronic expansion valve, isenthalpic pressure reduction is achieved, and the refrigerant flow rate is controlled via system signals. This maintains the superheat at the evaporator outlet at a certain level, preventing liquid refrigerant from leaving the evaporator and entering the compressor.

[0079] Furthermore, the high-temperature, high-pressure steam discharged from the compressor undergoes a phase change from gaseous to liquid after passing through the first condenser group (including the first condenser and the first condensing fan). A pressure sensor at the outlet of the first condenser monitors the real-time pressure value, and a temperature sensor at the outlet monitors the real-time temperature value. The controller calculates and outputs the subcooling value at the outlet of the first condenser based on the pressure and temperature values. The subcooling setpoint for the outlet of the first condenser is 0 K. The controller uses PID control to adjust the fan speed of the first condensing fan based on the real-time subcooling value and the setpoint, ensuring that the subcooling at the outlet of the first condenser remains constant within the setpoint deviation range. The refrigerant liquid passing through the outlet of the first condenser then passes through a subcooler group composed of a second condenser group (including the second condenser and the second condensing fan), a liquid receiver, and an economizer group (including a spiral economizer, a pulse solenoid valve, and a subcooling electronic expansion valve) to achieve multi-dimensional control of the subcooling. The function of the liquid receiver in the subcooler group is to ensure that there may be a small amount of gas residue after passing through the first condenser group, and that the refrigerant entering the second condenser group after passing through the liquid receiver is a pure liquid refrigerant.

[0080] In addition, the subcooling control system also includes a refrigerant dryer filter D1, a sight glass SGN, and a gas-liquid separator RA. The refrigerant dryer filter D1 absorbs moisture in the system and blocks impurities, preventing ice and dirt blockage in the system piping. The sight glass SGN is used to observe the refrigerant level, determine if the system is operating properly, and detect the presence of water vapor downstream of the refrigerant dryer filter. The gas-liquid separator RA contains the returned refrigerant, preventing liquid slugging in the compressor and dilution of the compressor oil by excessive refrigerant.

[0081] The subcooling control system provided in this embodiment belongs to the same inventive concept as the subcooling control method 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 subcooling control method provided in any embodiment of the present invention.

[0082] 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 method for controlling subcooling, characterized in that, The subcooling includes at least one of the subcooling at the condenser outlet and the subcooling at the expansion valve inlet. The condenser inlet is connected to the compressor, and the condenser outlet is connected to the evaporator. An expansion valve and a solenoid valve are installed in the connecting pipe between the condenser and the evaporator. The solenoid valve is located on the side of the expansion valve closer to the evaporator. A condenser fan is installed near the condenser. The subcooling control method includes: Obtain the current temperature and pressure at the condenser outlet, and the current temperature and pressure at the expansion valve inlet; The current subcooling of the condenser outlet is determined based on the current temperature and pressure at the condenser outlet, and the current subcooling of the expansion valve inlet is determined based on the current temperature and pressure at the expansion valve inlet. Based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet, the operating states of the condenser fan, the expansion valve, and the solenoid valve are controlled to adjust the subcooling at the condenser outlet and the subcooling at the expansion valve inlet. The condenser includes a first condenser and a second condenser, and the condensing fan includes a first condensing fan and a second condensing fan. The first condensing fan is located near the first condenser, and the second condensing fan is located near the second condenser. The inlet of the first condenser is connected to the compressor, and the outlet of the first condenser is connected to the inlet of the liquid storage tank. The outlet of the liquid storage tank is connected to the inlet of the second condenser, and the outlet of the second condenser is connected to the inlet of the evaporator. The outlet of the second condenser is connected to the inlet of the evaporator through a spiral economizer. The solenoid valve and the expansion valve are located in a branch line of the pipeline connecting the outlet of the spiral economizer and the inlet of the evaporator. The step of controlling the operating states of the condenser fan, the expansion valve, and the solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet includes: The operating state of the first condenser fan is controlled according to the current subcooling at the outlet of the first condenser in order to adjust the subcooling at the outlet of the first condenser. Based on the current subcooling at the inlet of the expansion valve, the operating states of the second condensing fan, the expansion valve, and the solenoid valve are controlled to adjust the subcooling at the inlet of the expansion valve. The solenoid valve is a pulse solenoid valve, used for periodic cycling to regulate the refrigerant flow rate under constant pressure.

2. The subcooling control method according to claim 1, characterized in that, The step of controlling the operating states of the second condensing fan, the expansion valve, and the solenoid valve based on the current subcooling at the inlet of the expansion valve includes: When the current subcooling at the inlet of the expansion valve is within a preset small subcooling range, the wind speed of the second condenser fan is adjusted to control the difference between the current subcooling at the inlet of the expansion valve and the preset first subcooling within a preset first range. When the current subcooling at the inlet of the expansion valve is in the preset intermediate subcooling range, the on / off time of the solenoid valve is adjusted to control the difference between the current subcooling at the inlet of the expansion valve and the preset second subcooling within the preset second range. When the current subcooling at the inlet of the expansion valve is in the preset large subcooling range, the opening of the expansion valve is adjusted to control the difference between the current subcooling at the inlet of the expansion valve and the preset third subcooling within the preset third range.

3. The subcooling control method according to claim 1, characterized in that, The step of controlling the operating states of the condenser fan, the expansion valve, and the solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet includes: When the current subcooling degree at the inlet of the expansion valve is within a preset small subcooling degree range, the expansion valve and the solenoid valve are controlled to be in the closed state. When the current subcooling degree at the inlet of the expansion valve is in the preset medium subcooling degree range or the preset large subcooling degree range, the expansion valve and the solenoid valve are controlled to be in operation.

4. The subcooling control method according to claim 1, characterized in that, The step of controlling the operating states of the condenser fan, the expansion valve, and the solenoid valve based on the current subcooling at the condenser outlet and the current subcooling at the expansion valve inlet includes: When the current subcooling degree at the inlet of the expansion valve is in the preset medium subcooling degree range or the preset large subcooling degree range, the solenoid valve is controlled to be in 100% output operation state.

5. The subcooling control method according to claim 1, characterized in that, The control of the operating states of the condenser fan, the expansion valve, and the solenoid valve includes: The working status of the condenser fan, the solenoid valve, and the expansion valve is controlled by PID regulation.

6. A subcooling control device, characterized in that, The subcooling includes at least one of the subcooling at the condenser outlet and the subcooling at the expansion valve inlet. The condenser inlet is connected to the compressor, and the condenser outlet is connected to the evaporator. An expansion valve and a solenoid valve are installed in the connecting pipe between the condenser and the evaporator. The solenoid valve is located on the side of the expansion valve closer to the evaporator. A condenser fan is installed near the condenser. The subcooling control device includes: The data acquisition module is used to acquire the current temperature and pressure at the outlet of the condenser and the current temperature and pressure at the inlet of the expansion valve. The subcooling determination module is used to determine the current subcooling of the condenser outlet based on the current temperature and pressure of the condenser outlet, and to determine the current subcooling of the expansion valve inlet based on the current temperature and pressure of the expansion valve inlet. The status control module is used to control the working status of the condenser fan, the expansion valve and the solenoid valve according to the current subcooling of the condenser outlet and the current subcooling of the expansion valve inlet, so as to adjust the subcooling of the condenser outlet and the subcooling of the expansion valve inlet. The condenser includes a first condenser and a second condenser, and the condensing fan includes a first condensing fan and a second condensing fan. The first condensing fan is located near the first condenser, and the second condensing fan is located near the second condenser. The inlet of the first condenser is connected to the compressor, and the outlet of the first condenser is connected to the inlet of the liquid storage tank. The outlet of the liquid storage tank is connected to the inlet of the second condenser, and the outlet of the second condenser is connected to the inlet of the evaporator. The outlet of the second condenser is connected to the inlet of the evaporator through a spiral economizer. The solenoid valve and the expansion valve are located in a branch line of the pipeline connecting the outlet of the spiral economizer and the inlet of the evaporator. The status control module is specifically used for: The operating state of the first condenser fan is controlled according to the current subcooling at the outlet of the first condenser in order to adjust the subcooling at the outlet of the first condenser. Based on the current subcooling at the inlet of the expansion valve, the operating states of the second condensing fan, the expansion valve, and the solenoid valve are controlled to adjust the subcooling at the inlet of the expansion valve. The solenoid valve is a pulse solenoid valve, used for periodic cycling to regulate the refrigerant flow rate under constant pressure.

7. A subcooling control system, characterized in that, include: Compressors, condensers, condensing fans, evaporators, solenoid valves, expansion valves, and controllers; The condenser inlet is connected to the compressor outlet, the condenser outlet is connected to the evaporator inlet, the evaporator outlet is connected to the compressor inlet, the expansion valve and the solenoid valve are located in the connecting pipe between the condenser and the evaporator, the solenoid valve is located on the side of the expansion valve closer to the evaporator, and the condensing fan is close to the condenser; the compressor, the condensing fan, the solenoid valve and the expansion valve are all electrically connected to the controller, and the subcooling control device as described in claim 6 is integrated into the controller.

8. The subcooling control system according to claim 7, characterized in that, The condenser includes a first condenser and a second condenser, and the condensing fan includes a first condensing fan and a second condensing fan. The first condensing fan is close to the first condenser, and the second condensing fan is close to the second condenser. The inlet of the first condenser is connected to the outlet of the compressor, the outlet of the first condenser is connected to the inlet of the liquid storage tank, the outlet of the liquid storage tank is connected to the inlet of the second condenser, and the outlet of the second condenser is connected to the inlet of the evaporator.

9. The subcooling control system according to claim 8, characterized in that, It also includes a spiral economizer, a temperature sensor, and a pressure sensor. The outlet of the second condenser is connected to the inlet of the evaporator through the spiral economizer. The outlet of the second condenser is also connected to the inlet of the compressor through the spiral economizer. The temperature sensor and the pressure sensor are provided at the outlet of the first condenser and on the side of the expansion valve near the evaporator.

Images