Refrigerant recovery method and apparatus for direct expansion system

Abstract

The application provides a refrigerant recovery method and device of a direct cooling system. The refrigerant recovery method of the direct cooling system comprises the following steps: when a refrigerant recovery instruction is received, the direct cooling system is controlled to enter a refrigerant recovery mode. In the refrigerant recovery mode, the refrigerant flows from a first heat exchanger to a second heat exchanger through a first valve, and flows from the second heat exchanger to a compressor through a second valve. When the first system pipeline pressure at the outlet of the compressor is less than a first preset pressure, and / or the running time of the compressor in the refrigerant recovery mode is greater than a first preset time, the first valve is closed. When the second system pipeline pressure at the inlet of the compressor is less than a second preset pressure, the second valve is closed, and the compressor is stopped. The application at least improves the problem of low refrigerant recovery efficiency of the direct cooling system.

Description

Technical Field

[0001] This application relates to the field of refrigerant treatment technology, and in particular to a refrigerant recovery method and apparatus for a direct cooling system. Background Technology

[0002] In actual operation, direct-cooling systems have an urgent need for refrigerant recovery. As the core heat transfer medium in direct-cooling systems, effective management and recycling of the refrigerant not only improves the overall energy efficiency of the system but also significantly reduces its adverse environmental impact. During after-sales battery maintenance, refrigerant recovery from the direct-cooling system can minimize refrigerant loss and avoid the need for refrigerant top-ups. In developing this application, the inventors discovered that the prior art suffers from at least the following technical problem: the refrigerant recovery efficiency of existing direct-cooling systems is low. Refrigerant recovery efficiency refers to the proportion of recovered refrigerant to the amount of refrigerant before recovery. Summary of the Invention

[0003] This application provides a refrigerant recovery method and apparatus for a direct cooling system, which at least improves the problem of low refrigerant recovery efficiency in direct cooling systems.

[0004] According to a first aspect of the embodiments of this application, a refrigerant recovery method for a direct cooling system is provided. The direct cooling system includes a compressor, a first heat exchanger, a second heat exchanger, a first valve, and a second valve connected to each other. The second heat exchanger is used to exchange heat with multiple batteries in an energy storage system.

[0005] The method includes:

[0006] When a refrigerant recovery command is received, the direct cooling system is controlled to enter the refrigerant recovery mode. In the refrigerant recovery mode, the refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve, and from the second heat exchanger to the compressor through the second valve.

[0007] If the pressure in the first system pipeline at the outlet of the compressor is less than the first preset pressure, and / or if the operating time of the compressor in the refrigerant recovery mode is greater than the first preset time, the first valve is instructed to close.

[0008] If the pressure in the second system pipeline at the compressor inlet is less than the second preset pressure, the second valve is instructed to close, and the compressor is controlled to stop.

[0009] Optionally, instructing the first valve to close includes:

[0010] Output a first prompt message, wherein the first prompt message is used to remind the user to manually close the first valve;

[0011] or,

[0012] Control the first valve to close.

[0013] Optionally, instructing the second valve to close includes:

[0014] Output a second prompt message, wherein the second prompt message is used to remind the user to manually close the second valve;

[0015] or,

[0016] Control the second valve to close.

[0017] Optionally, controlling the compressor to stop includes:

[0018] The compressor is controlled to decelerate, and after the second valve is instructed to close, the compressor is controlled to stop after a second preset time.

[0019] Optionally, the method further includes:

[0020] If the first valve is not closed, the second valve is not closed, and the compressor's operating time in the refrigerant recovery mode exceeds the preset maximum operating time, the compressor is controlled to stop and a third prompt message is output, wherein the third prompt message is used to indicate that refrigerant recovery has failed.

[0021] Optionally, the method further includes:

[0022] If the pressure in the first system pipeline at the outlet of the compressor is greater than the third preset pressure, a fourth prompt message is output, wherein the fourth prompt message is used to indicate that the pressure in the first system pipeline at the outlet of the compressor is too high.

[0023] Optionally, the direct cooling system further includes a fan, a third heat exchanger, a refrigeration electronic expansion valve, a heating electronic expansion valve, and a gas injection electronic expansion valve; the fan is disposed on one side of the first heat exchanger; the third heat exchanger includes a first heat exchange section and a second heat exchange section that exchanges heat with the first heat exchange section; the first heat exchanger is connected to a first end of the first heat exchange section, the second end of the first heat exchange section is connected to a first end of the refrigeration electronic expansion valve, the second end of the refrigeration electronic expansion valve is connected to the first valve, the second end of the first heat exchange section is connected to a first end of the gas injection electronic expansion valve, the second heat exchange section is connected between the second end of the gas injection electronic expansion valve and the gas injection port of the compressor, and the heating electronic expansion valve is connected between the second end of the first heat exchange section and the first heat exchanger;

[0024] The control of the direct cooling system to enter the refrigerant recovery mode includes:

[0025] The compressor's operating frequency is adjusted to a preset frequency, the fan is controlled to run at full speed, the opening of the refrigeration electronic expansion valve is adjusted according to the suction superheat, the heating electronic expansion valve is controlled to close, and the gas replenishment electronic expansion valve is controlled to close.

[0026] Optionally, the method further includes:

[0027] If the pressure in the first system pipeline at the outlet of the compressor is less than the first preset pressure, and / or if the operating time of the compressor in the refrigerant recovery mode is greater than the first preset time, the refrigeration electronic expansion valve is controlled to close.

[0028] If the pressure in the second system pipeline at the compressor inlet is less than the second preset pressure, the fan is controlled to shut down after a delay.

[0029] Optionally, the method further includes:

[0030] In the refrigerant recovery mode, the alarms for the compressor and the fan are turned off.

[0031] According to a second aspect of the embodiments of this application, a refrigerant recovery device for a direct cooling system is provided. The direct cooling system includes a compressor, a first heat exchanger, a second heat exchanger, a first valve, and a second valve connected to each other. The second heat exchanger is used to exchange heat with multiple batteries in an energy storage system.

[0032] The refrigerant recovery device includes:

[0033] The control unit is configured to control the direct cooling system to enter the refrigerant recovery mode when a refrigerant recovery command is received, wherein, in the refrigerant recovery mode, refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve, and from the second heat exchanger to the compressor through the second valve;

[0034] The first processing unit is configured to instruct the first valve to close when the first system pipeline pressure at the outlet of the compressor is less than a first preset pressure, and / or when the compressor's operating time in the refrigerant recovery mode is greater than a first preset time.

[0035] The second processing unit is used to instruct the second valve to close and control the compressor to stop when the pressure in the second system pipeline at the compressor inlet is less than the second preset pressure.

[0036] In this application, the direct cooling system includes a compressor, a first heat exchanger, a second heat exchanger, a first valve, and a second valve connected to each other. The second heat exchanger is used to exchange heat with multiple batteries in the energy storage system. When a refrigerant recovery command is received, the direct cooling system is controlled to enter the refrigerant recovery mode. In the refrigerant recovery mode, the refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve, and from the second heat exchanger to the compressor through the second valve.

[0037] When the pressure in the first system line at the compressor outlet is less than the first preset pressure, and / or the compressor's operating time in refrigerant recovery mode exceeds the first preset time, some refrigerant in the second heat exchanger has been recovered. Since refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve in refrigerant recovery mode, the first valve is closed to prevent the recovered refrigerant from flowing back into the second heat exchanger. When the pressure in the second system line at the compressor inlet is less than the second preset pressure, the refrigerant in the second heat exchanger undergoes heat exchange and flows out of the second heat exchanger. The refrigerant in the second heat exchanger has been completely recovered, and there is no refrigerant left in the second heat exchanger. In refrigerant recovery mode, refrigerant flows from the second heat exchanger to the compressor through the second valve. At this time, the second valve is closed to prevent refrigerant leakage into the second heat exchanger and to stop the compressor, thus halting refrigerant recovery. This reduces the possibility of refrigerant residue in the second heat exchanger and improves the refrigerant recovery efficiency of the direct-cooling system. During after-sales battery installation and removal in the energy storage system, the second heat exchanger is used to exchange heat between multiple batteries. Refrigerant recovery reduces the possibility of refrigerant residue in the second heat exchanger, thereby significantly reducing the direct release of refrigerant into the air, eliminating the need for refrigerant replenishment, and further improving the refrigerant recovery efficiency of the direct-cooling system. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0039] Figure 1 This is a schematic flowchart of a refrigerant recovery method for a direct cooling system provided in an embodiment of this application;

[0040] Figure 2 This is a schematic diagram of a direct cooling system in refrigerant recovery mode provided in an embodiment of this application;

[0041] Figure 3 This is a schematic diagram of the structure of a direct cooling system provided in an embodiment of this application;

[0042] Figure 4 This is a schematic flowchart of a refrigerant recovery method for a direct cooling system provided in an embodiment of this application;

[0043] Figure 5 This is a schematic diagram of the refrigerant recovery device for a direct cooling system provided in the embodiments of this application. Detailed Implementation

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] Exemplary methods

[0046] Please see Figure 1 In one exemplary embodiment, a refrigerant recovery method for a direct cooling system is provided. The direct cooling system includes a compressor, a first heat exchanger, a second heat exchanger, a first valve, and a second valve connected to each other. The second heat exchanger is used to exchange heat with multiple batteries in an energy storage system.

[0047] like Figure 1 As shown, the refrigerant recovery method for a direct-cooling system mainly includes the following steps:

[0048] Step 101: When a refrigerant recovery command is received, control the direct cooling system to enter the refrigerant recovery mode.

[0049] In the refrigerant recovery mode, the refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve, and from the second heat exchanger to the compressor through the second valve.

[0050] In some embodiments, such as Figure 2 The diagram shown is a schematic of a direct cooling system in refrigerant recovery mode. Figure 2 In this direct-cooling system, a compressor, a first heat exchanger, a second heat exchanger, a first valve, and a second valve are interconnected. In refrigerant recovery mode, the first heat exchanger is connected between the compressor outlet and the first valve; the first valve is connected between the first and second heat exchangers; the second heat exchanger is connected between the first and second valves; and the second valve is connected between the second heat exchanger and the compressor inlet. In refrigerant recovery mode, refrigerant flows from the compressor outlet to the first heat exchanger, from the first heat exchanger through the first valve to the second heat exchanger, and from the second heat exchanger through the second valve to the compressor inlet. Figure 2The document only shows a direct cooling system including a compressor, a first heat exchanger, a second heat exchanger, a first valve, and a second valve. As needed, the direct cooling system may also include other components, such as a fan, etc. This application does not limit this. Figure 2 The diagrams of the various components are for illustrative purposes only and do not impose restrictions on the selection of any component. For example, Figure 2 The first valve in the system can be either a mechanical valve or an electronic valve, and the second valve can also be either a mechanical valve or an electronic valve.

[0051] In the exemplary embodiment, the first heat exchanger can be an outdoor heat exchanger, and the second heat exchanger can be a cold plate. The number of cold plates is not limited. The second heat exchanger is used to exchange heat with multiple batteries in the energy storage system. The cold plate and multiple batteries in the energy storage system can be in direct contact to exchange heat with multiple batteries in the energy storage system through direct cooling.

[0052] In some embodiments, such as Figure 3 The diagram shown is a schematic of a direct cooling system. Figure 3 The direct cooling system includes a compressor, a first heat exchanger, a second heat exchanger, a first valve, a second valve, a fan, a third heat exchanger, a refrigeration electronic expansion valve, a heating electronic expansion valve, and a gas injection electronic expansion valve. The fan is located on one side of the first heat exchanger. The third heat exchanger includes a first heat exchange section and a second heat exchange section that exchanges heat with the first heat exchange section. The first heat exchanger is connected between the compressor outlet and the first end of the first heat exchange section. The second end of the first heat exchange section is connected to the first end of the refrigeration electronic expansion valve, and the second end of the refrigeration electronic expansion valve is connected to the first valve. The second heat exchanger is connected between the first valve and the second valve. The second valve is connected between the second heat exchanger and the compressor inlet. The second end of the first heat exchange section is connected to the first end of the gas injection electronic expansion valve, and the second heat exchange section is connected between the second end of the gas injection electronic expansion valve and the compressor's gas injection port. The heating electronic expansion valve is connected between the second end of the first heat exchange section and the first heat exchanger.

[0053] Figure 3 The document only shows a direct cooling system including a compressor, a first heat exchanger, a second heat exchanger, a first valve, a second valve, a fan, a third heat exchanger, a refrigeration electronic expansion valve, a heating electronic expansion valve, and a gas replenishment electronic expansion valve. As needed, the direct cooling system may also include other components, such as a four-way valve, a liquid receiver, an oil separator, a gas-liquid separator, a filter, a pressure sensor, a temperature sensor, a check valve, etc. This application does not impose any limitations on this. Figure 3 The diagrams of the various components are for illustrative purposes only and do not impose restrictions on the selection of any component. For example, Figure 3 The first valve in the system can be either a mechanical valve or an electronic valve, and the second valve can also be either a mechanical valve or an electronic valve.

[0054] In the exemplary embodiment, the first heat exchanger can be an outdoor heat exchanger, and the second heat exchanger can be a cold plate. The number of cold plates is not limited. The second heat exchanger is used to exchange heat with multiple batteries in the energy storage system. The cold plate and the multiple batteries in the energy storage system can be in direct contact, exchanging heat with the multiple batteries in the energy storage system through direct cooling. The third heat exchanger can be an economizer.

[0055] In some embodiments, the direct cooling system may further include a four-way valve, wherein the first port of the four-way valve is connected to the first heat exchanger, the second port of the four-way valve is connected to the outlet of the compressor, the third port of the four-way valve is connected to the inlet of the compressor, and the fourth port of the four-way valve is connected to the second valve.

[0056] In cooling mode, the coil of the four-way valve is de-energized, the first port and the second port of the four-way valve are connected, the third port and the fourth port of the four-way valve are connected, and the refrigerant flows from the compressor outlet to the first heat exchanger, from the first heat exchanger through the first valve to the second heat exchanger, and from the second heat exchanger through the second valve to the compressor inlet.

[0057] In refrigerant recovery mode, the coil of the four-way valve is de-energized, the first port and the second port of the four-way valve are connected, the third port and the fourth port of the four-way valve are connected, and the refrigerant flows from the compressor outlet to the first heat exchanger, from the first heat exchanger through the first valve to the second heat exchanger, and from the second heat exchanger through the second valve to the compressor inlet.

[0058] In heating mode, the coil of the four-way valve is energized, the first port and the third port of the four-way valve are connected, the second port and the fourth port of the four-way valve are connected, and the refrigerant flows from the compressor outlet through the second valve to the second heat exchanger, from the second heat exchanger through the first valve to the first heat exchanger, and from the first heat exchanger to the compressor inlet.

[0059] In some embodiments, controlling the direct cooling system to enter refrigerant recovery mode includes:

[0060] The compressor's operating frequency is adjusted to the preset frequency, the fan is controlled to run at full speed, the opening of the refrigeration electronic expansion valve is adjusted according to the suction superheat, the heating electronic expansion valve is controlled to close, and the gas replenishment electronic expansion valve is controlled to close.

[0061] In an exemplary embodiment, adjusting the compressor's operating frequency to a preset frequency can be achieved by controlling the compressor to adjust its operating frequency to the preset frequency according to the system compressor's frequency increase / decrease rate. After the compressor's operating frequency is adjusted to the preset frequency, the compressor continues to operate at the preset frequency.

[0062] In the exemplary embodiment, the preset frequency refers to the preset operating frequency of the refrigerant transfer compressor. For example, the preset frequency can be 45 rps, where rps is an abbreviation for "revolutions per second".

[0063] In an exemplary embodiment, controlling the fan to run at full speed can be achieved by increasing the frequency of the fan to run at full speed. In this case, the fan is not subject to the regulation of the first system pipeline pressure (i.e., high pressure) at the compressor outlet.

[0064] Adjusting the compressor's operating frequency to a preset frequency and controlling the fan to run at full speed accelerates refrigerant flow, thereby increasing refrigerant recovery speed. Adjusting the opening of the refrigeration electronic expansion valve based on the suction superheat, and controlling the closing of the heating electronic expansion valve and the makeup gas electronic expansion valve, allows refrigerant to flow from the compressor outlet to the first heat exchanger, and from the first heat exchanger through the first heat exchange section of the third heat exchanger to the refrigeration electronic expansion valve. Because the makeup gas electronic expansion valve is closed, refrigerant will not flow through it to the second heat exchange section of the third heat exchanger, nor from the second heat exchange section of the third heat exchanger to the compressor's makeup gas port. Similarly, because the heating electronic expansion valve is closed, refrigerant will not flow from the first heat exchanger through the heating electronic expansion valve to the refrigeration electronic expansion valve. The refrigerant flows from the refrigeration electronic expansion valve through the first valve to the second heat exchanger, and from the second heat exchanger through the second valve to the compressor inlet.

[0065] In other embodiments, controlling the direct cooling system to enter refrigerant recovery mode includes:

[0066] Adjust the compressor's operating frequency to the preset frequency, control the fan to run at full speed, adjust the opening of the refrigeration electronic expansion valve to the preset opening, control the heating electronic expansion valve to close, and control the gas replenishment electronic expansion valve to close.

[0067] Step 102: If the pressure in the first system pipeline at the compressor outlet is less than the first preset pressure, and / or the compressor's operating time in refrigerant recovery mode is longer than the first preset time, instruct the first valve to close.

[0068] In an exemplary embodiment, a high-pressure sensor can be installed at the outlet of the compressor to detect the pressure of the first system pipeline at the outlet of the compressor, which is also the high-pressure pressure.

[0069] In the exemplary embodiment, the first preset pressure refers to a preset refrigerant transfer high pressure, for example, the first preset pressure can be 2.3 MPaG. MPaG is a unit for expressing gauge pressure, where MPa is a unit of pressure, i.e., megapascal, and G represents gauge pressure, which is the pressure indicated by a pressure gauge, and is a pressure value relative to atmospheric pressure.

[0070] In the exemplary embodiment, the first preset duration refers to the preset duration of refrigerant transfer, for example, the first preset duration may be 2 minutes.

[0071] In some embodiments, step 102 may include: instructing the first valve to close when the first system line pressure at the compressor outlet is less than a first preset pressure. Step 102 may also include: instructing the first valve to close when the compressor's operating time in refrigerant recovery mode is greater than a first preset time. Step 102 may further include: instructing the first valve to close when the first system line pressure at the compressor outlet is less than the first preset pressure and the compressor's operating time in refrigerant recovery mode is greater than the first preset time. This application does not limit this to these embodiments.

[0072] When the pressure in the first system pipeline at the compressor outlet is less than the first preset pressure, and / or when the compressor runs for a longer period of time in refrigerant recovery mode than the first preset duration, some of the refrigerant in the second heat exchanger has been recovered. Since the refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve in refrigerant recovery mode, the first valve is instructed to close to prevent the recovered refrigerant from flowing back into the second heat exchanger.

[0073] In some embodiments, instructing the first valve to close can be implemented in various ways, including but not limited to the following:

[0074] Method 1

[0075] If the first valve is a mechanical valve, a first prompt message is output, which is used to remind the user to manually close the first valve.

[0076] The first valve is a mechanical valve, for example, a gate valve.

[0077] For example, the first prompt message can be displayed in a pop-up window on the handheld device's screen, or the handheld device can simultaneously sound an alarm, or an external alarm device can be connected to the handheld device. Of course, there are other ways to output the first prompt message, and this application does not limit this.

[0078] When the first valve is a mechanical valve, a first prompt message is output, which is used to remind the user to manually close the first valve, so as to prevent the recovered refrigerant from flowing back into the second heat exchanger.

[0079] Method 2

[0080] If the first valve is an electronic valve, control the first valve to close.

[0081] The first valve is an electronic valve, for example, the first valve is a solenoid valve.

[0082] When the first valve is an electronic valve, controlling the first valve to close automatically eliminates the need for manual closure, thus increasing the speed of refrigerant recovery. This enables fully automatic refrigerant recovery upon receiving a refrigerant recovery command, with no manual intervention required throughout the entire process.

[0083] In some embodiments, the refrigerant recovery method for a direct cooling system further includes:

[0084] If the pressure in the first system pipeline at the compressor outlet is less than the first preset pressure, and / or if the compressor operates for a longer period of time in refrigerant recovery mode than the first preset duration, the electronic expansion valve for refrigerant control will be closed.

[0085] When the pressure in the first system pipeline at the compressor outlet is less than the first preset pressure, and / or when the compressor runs for a longer period of time in refrigerant recovery mode than the first preset time, some of the refrigerant in the second heat exchanger has been recovered. Since the refrigerant flows from the refrigeration electronic expansion valve to the second heat exchanger through the first valve in refrigerant recovery mode, the refrigeration electronic expansion valve is closed at this time to prevent the recovered refrigerant from flowing through the refrigeration electronic expansion valve to the first valve and then into the second heat exchanger through the first valve.

[0086] In an exemplary embodiment, the execution order of the two steps of controlling the refrigeration electronic expansion valve to close and instructing the first valve to close can be performed simultaneously; or the step of controlling the refrigeration electronic expansion valve to close can be performed first, followed by the step of instructing the first valve to close; or the step of instructing the first valve to close can be performed first, followed by the step of controlling the refrigeration electronic expansion valve to close.

[0087] Step 103: When the pressure in the second system pipeline at the compressor inlet is less than the second preset pressure, instruct the second valve to close and control the compressor to stop.

[0088] In an exemplary embodiment, a low-pressure sensor can be installed at the inlet of the compressor to detect the pressure of the second system pipeline at the inlet of the compressor, which is the low-pressure pressure.

[0089] In the exemplary embodiment, the second preset pressure refers to the preset refrigerant transfer low pressure, for example, the second preset pressure can be 0.2 MPaG.

[0090] When the pressure in the second system pipeline at the compressor inlet is lower than the second preset pressure, the refrigerant in the second heat exchanger flows out after heat exchange, indicating that the refrigerant in the second heat exchanger has been completely recovered and there is no refrigerant left. Since the refrigerant flows from the second heat exchanger to the compressor through the second valve in refrigerant recovery mode, the second valve is instructed to close to prevent refrigerant leakage into the second heat exchanger and to stop the compressor, thus reducing the possibility of refrigerant residue in the second heat exchanger and improving the refrigerant recovery efficiency of the direct cooling system. During the after-sales disassembly and installation of batteries in the energy storage system, since the second heat exchanger is used to exchange heat between multiple batteries in the energy storage system, refrigerant recovery reduces the possibility of refrigerant residue in the second heat exchanger, thereby greatly reducing the direct emission of refrigerant into the air, eliminating the need for refrigerant replenishment, and improving the refrigerant recovery efficiency of the direct cooling system.

[0091] In some embodiments, there are multiple ways to instruct the second valve to close, including but not limited to the following:

[0092] Method 1

[0093] If the second valve is a mechanical valve, a second prompt message is output, which is used to remind the user to manually close the second valve.

[0094] The second valve is a mechanical valve, for example, a gate valve.

[0095] For example, outputting the second prompt message could be done by displaying it as a pop-up on the handheld device's screen, while simultaneously disabling the output of the first prompt message, i.e., stopping the buzzer and alarm. Of course, there are other ways to output the second prompt message, and this application does not limit this.

[0096] When the second valve is a mechanical valve, a second prompt message is output. This second prompt message is used to remind the user to manually close the second valve, thus preventing refrigerant from leaking into the second heat exchanger through the second valve.

[0097] Method 2

[0098] If the second valve is an electronic valve, control the second valve to close.

[0099] The second valve is an electronic valve, for example, a solenoid valve.

[0100] When the second valve is an electronic valve, controlling the second valve to close it can automatically close it without manual intervention, thereby increasing the speed of refrigerant recovery. This enables fully automatic refrigerant recovery upon receiving a refrigerant recovery command, and the entire refrigerant recovery process requires no manual intervention.

[0101] In some embodiments, the refrigerant recovery method for a direct cooling system further includes:

[0102] If the pressure in the second system pipeline at the compressor inlet is less than the second preset pressure, the control fan will be delayed and shut down.

[0103] When the pressure in the second system pipeline at the compressor inlet is lower than the second preset pressure, the refrigerant in the second heat exchanger flows out after heat exchange, and the refrigerant in the second heat exchanger has been completely recovered. There is no refrigerant in the second heat exchanger, and the control fan is delayed to shut down, thereby stopping all operating components of the direct cooling system and closing all electronic expansion valves of the direct cooling system. No manual operation is required, and the automatic recovery of refrigerant in the second heat exchanger of the direct cooling system is achieved.

[0104] In some embodiments, controlling the compressor to stop includes: controlling the compressor to decelerate and, after instructing the second valve to close, controlling the compressor to stop after a second preset time period.

[0105] In an exemplary embodiment, the second preset duration refers to the preset interval between instructing the second valve to close and the compressor to stop. For example, the second preset duration could be 30 seconds.

[0106] The compressor is controlled to decelerate and, after the second valve is closed, the compressor is stopped after a second preset time. The compressor is then stopped after a delay, and the refrigerant flowing out of the second heat exchanger is further recovered into the first heat exchanger or into other components such as a liquid receiver. This achieves automatic compressor shutdown after refrigerant recovery, eliminating the need for manual shutdown and enabling automatic refrigerant recovery in the second heat exchanger of the direct cooling system.

[0107] In some embodiments, the refrigerant recovery method for a direct cooling system further includes: if the first valve is not closed, the second valve is not closed, and the compressor's operating time in refrigerant recovery mode is greater than a preset maximum operating time, controlling the compressor to stop and outputting a third prompt message, wherein the third prompt message is used to indicate that refrigerant recovery has failed.

[0108] In the exemplary embodiment, the preset maximum running time refers to the preset maximum running time of the refrigerant recovery logic compressor.

[0109] If the first valve is not closed, the second valve is not closed, and the compressor's operating time in refrigerant recovery mode exceeds the preset maximum operating time, it indicates that refrigerant recovery has failed. In this case, the compressor is stopped to prevent it from running continuously at the preset frequency, thus achieving automatic compressor shutdown in the event of refrigerant recovery failure. A third prompt message is output to indicate the refrigerant recovery failure and remind the user.

[0110] In some embodiments, the refrigerant recovery method for a direct cooling system further includes: outputting a fourth prompt message when the pressure in the first system line at the compressor outlet is greater than a third preset pressure, wherein the fourth prompt message is used to indicate that the pressure in the first system line at the compressor outlet is too high.

[0111] It enables high-pressure alarm for refrigerant recovery, promptly alerting users when the pressure in the first system pipeline at the compressor outlet is too high.

[0112] In some embodiments, the refrigerant recovery method for a direct cooling system further includes:

[0113] In refrigerant recovery mode, alarms for the compressor and fan are turned off.

[0114] In cooling mode, the compressor and fan will alarm under preset conditions. However, in refrigerant recovery mode, even if the compressor and fan meet the preset conditions, they are in normal working condition under refrigerant recovery mode and do not need to alarm. Therefore, in refrigerant recovery mode, the alarms of the compressor and fan are turned off. The compressor and fan are not subject to alarm shutdown outside of refrigerant recovery mode, do not execute oil return logic, and do not execute three-level protection logic.

[0115] In some embodiments, such as Figure 4 As shown, the refrigerant recovery method for a direct-cooling system mainly includes the following steps:

[0116] Step 401: When a refrigerant recovery command is received, the operating frequency of the compressor is adjusted to the preset frequency, the fan is controlled to run at full speed, the opening of the refrigeration electronic expansion valve is adjusted according to the suction superheat, the heating electronic expansion valve is controlled to close, and the gas replenishment electronic expansion valve is controlled to close.

[0117] The refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve, and from the second heat exchanger to the compressor through the second valve.

[0118] Step 402: If the pressure in the first system pipeline at the compressor outlet is less than the first preset pressure, and / or the compressor's operating time in refrigerant recovery mode is longer than the first preset time, the first valve is instructed to close, and the refrigeration electronic expansion valve is controlled to close.

[0119] Step 403: When the pressure in the second system pipeline at the compressor inlet is less than the second preset pressure, the second valve is instructed to close, the compressor is controlled to decelerate, and after the second valve is instructed to close, the compressor is controlled to stop after a second preset time, and the fan is controlled to shut down after a delay.

[0120] In summary, in this application, the direct cooling system includes a compressor, a first heat exchanger, a second heat exchanger, a first valve, and a second valve connected to each other. The second heat exchanger is used to exchange heat with multiple batteries in the energy storage system. When a refrigerant recovery command is received, the direct cooling system is controlled to enter the refrigerant recovery mode. In the refrigerant recovery mode, the refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve, and from the second heat exchanger to the compressor through the second valve.

[0121] When the pressure in the first system line at the compressor outlet is less than the first preset pressure, and / or the compressor's operating time in refrigerant recovery mode exceeds the first preset time, some refrigerant in the second heat exchanger has been recovered. Since refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve in refrigerant recovery mode, the first valve is closed to prevent the recovered refrigerant from flowing back into the second heat exchanger. When the pressure in the second system line at the compressor inlet is less than the second preset pressure, the refrigerant in the second heat exchanger undergoes heat exchange and flows out of the second heat exchanger. The refrigerant in the second heat exchanger has been completely recovered, and there is no refrigerant left in the second heat exchanger. In refrigerant recovery mode, refrigerant flows from the second heat exchanger to the compressor through the second valve. At this time, the second valve is closed to prevent refrigerant leakage into the second heat exchanger and to stop the compressor, thus halting refrigerant recovery. This reduces the possibility of refrigerant residue in the second heat exchanger and improves the refrigerant recovery efficiency of the direct-cooling system. During after-sales battery installation and removal in the energy storage system, the second heat exchanger is used to exchange heat between multiple batteries. Refrigerant recovery reduces the possibility of refrigerant residue in the second heat exchanger, thereby significantly reducing the direct release of refrigerant into the air, eliminating the need for refrigerant replenishment, and further improving the refrigerant recovery efficiency of the direct-cooling system.

[0122] Exemplary device

[0123] Accordingly, this application also provides a refrigerant recovery device for a direct cooling system. The direct cooling system includes a compressor, a first heat exchanger, a second heat exchanger, a first valve, and a second valve connected to each other. The second heat exchanger is used to exchange heat with multiple batteries in the energy storage system.

[0124] like Figure 5 As shown, the refrigerant recovery device of the direct cooling system includes:

[0125] Control unit 501 is used to control the direct cooling system to enter the refrigerant recovery mode when a refrigerant recovery command is received, wherein, in the refrigerant recovery mode, refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve, and from the second heat exchanger to the compressor through the second valve;

[0126] The first processing unit 502 is configured to instruct the first valve to close when the first system pipeline pressure at the outlet of the compressor is less than a first preset pressure, and / or when the compressor's operating time in the refrigerant recovery mode is greater than a first preset time.

[0127] The second processing unit 503 is used to instruct the second valve to close and control the compressor to stop when the pressure in the second system pipeline at the inlet of the compressor is less than the second preset pressure.

[0128] The refrigerant recovery device for the direct-cooling system provided in this embodiment belongs to the same application concept as the refrigerant recovery method for the direct-cooling system provided in the above embodiments of this application. It can execute the refrigerant recovery method for the direct-cooling system provided in any of the above embodiments of this application, and has the corresponding functional modules and beneficial effects for executing the refrigerant recovery method for the direct-cooling system. Technical details not described in detail in this embodiment can be found in the specific processing content of the refrigerant recovery method for the direct-cooling system provided in the above embodiments of this application, and will not be repeated here.

[0129] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0130] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For apparatus embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0131] The steps in the methods of the various embodiments of this application can be adjusted, merged, or deleted in order according to actual needs, and the technical features described in each embodiment can be replaced or combined.

[0132] The modules and sub-modules in the apparatus of the various embodiments of this application can be merged, divided, and deleted according to actual needs.

[0133] It should be understood that the disclosed apparatus and methods can be implemented in other ways, given the several embodiments provided in this application. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of modules or sub-modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple sub-modules or modules may be combined or integrated into another module, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0134] The modules or submodules described as separate components may or may not be physically separate. The components that constitute a module or submodule may or may not be physical modules or submodules; that is, they may be located in one place or distributed across multiple network modules or submodules. Some or all of the modules or submodules can be selected to achieve the purpose of this embodiment's solution, depending on actual needs.

[0135] Furthermore, the functional modules or sub-modules in the various embodiments of this application can be integrated into one processing module, or each module or sub-module can exist physically separately, or two or more modules or sub-modules can be integrated into one module. The integrated modules or sub-modules described above can be implemented in hardware or in the form of software functional modules or sub-modules.

[0136] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0137] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software unit executed by a processor, or a combination of both. The software unit can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0138] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0139] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for refrigerant recovery in a direct cooling system, characterized in that, The direct cooling system includes a compressor, a first heat exchanger, a second heat exchanger, a first valve, and a second valve connected to each other. The second heat exchanger is used to exchange heat with multiple batteries in the energy storage system. The direct cooling system also includes a fan, a third heat exchanger, a cooling electronic expansion valve, a heating electronic expansion valve, and a gas-replenishing electronic expansion valve. The fan is located on one side of the first heat exchanger. The third heat exchanger includes a first heat exchange section and a second heat exchange section that exchanges heat with the first heat exchange section. The first heat exchanger is connected to a first end of the first heat exchange section, the second end of the first heat exchange section is connected to a first end of the cooling electronic expansion valve, the second end of the cooling electronic expansion valve is connected to the first valve, the second end of the first heat exchange section is connected to a first end of the gas-replenishing electronic expansion valve, the second heat exchange section is connected between the second end of the gas-replenishing electronic expansion valve and the gas-replenishing port of the compressor, and the heating electronic expansion valve is connected between the second end of the first heat exchange section and the first heat exchanger. The method includes: When a refrigerant recovery command is received, the direct cooling system is controlled to enter the refrigerant recovery mode: the operating frequency of the compressor is adjusted to a preset frequency, the fan is controlled to run at full speed, the opening of the refrigeration electronic expansion valve is adjusted according to the suction superheat, the heating electronic expansion valve is controlled to close, and the gas replenishment electronic expansion valve is controlled to close. In this mode, the refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve, and from the second heat exchanger to the compressor through the second valve. When the pressure in the first system pipeline at the outlet of the compressor is less than the first preset pressure, and the operating time of the compressor in the refrigerant recovery mode is greater than the first preset time, the first valve is instructed to close. If the pressure in the second system pipeline at the compressor inlet is less than the second preset pressure, the second valve is instructed to close, and the compressor is controlled to decelerate. After the second valve is instructed to close, the compressor is controlled to stop after a second preset time.

2. The refrigerant recovery method for a direct cooling system according to claim 1, characterized in that, The instruction to close the first valve includes: Output a first prompt message, wherein the first prompt message is used to remind the user to manually close the first valve; or, Control the first valve to close.

3. The refrigerant recovery method for a direct cooling system according to claim 1, characterized in that, The instruction to close the second valve includes: Output a second prompt message, wherein the second prompt message is used to remind the user to manually close the second valve; or, Control the second valve to close.

4. The refrigerant recovery method for a direct cooling system according to claim 1, characterized in that, The method further includes: If the first valve is not closed, the second valve is not closed, and the compressor's operating time in the refrigerant recovery mode exceeds the preset maximum operating time, the compressor is controlled to stop and a third prompt message is output, wherein the third prompt message is used to indicate that refrigerant recovery has failed.

5. The refrigerant recovery method for a direct cooling system according to claim 1, characterized in that, The method further includes: If the pressure in the first system pipeline at the outlet of the compressor is greater than the third preset pressure, a fourth prompt message is output, wherein the fourth prompt message is used to indicate that the pressure in the first system pipeline at the outlet of the compressor is too high.

6. The refrigerant recovery method for a direct cooling system according to claim 1, characterized in that, The method further includes: When the pressure in the first system pipeline at the outlet of the compressor is less than the first preset pressure, and the operating time of the compressor in the refrigerant recovery mode is greater than the first preset time, the refrigeration electronic expansion valve is controlled to close. If the pressure in the second system pipeline at the compressor inlet is less than the second preset pressure, the fan is controlled to shut down after a delay.

7. The refrigerant recovery method for a direct cooling system according to claim 1, characterized in that, The method further includes: In the refrigerant recovery mode, the alarms for the compressor and the fan are turned off.

8. A refrigerant recovery device for a direct cooling system, characterized in that, The direct cooling system includes a compressor, a first heat exchanger, a second heat exchanger, a first valve, and a second valve connected to each other. The second heat exchanger is used to exchange heat with multiple batteries in the energy storage system. The direct cooling system also includes a fan, a third heat exchanger, a cooling electronic expansion valve, a heating electronic expansion valve, and a gas-replenishing electronic expansion valve. The fan is located on one side of the first heat exchanger. The third heat exchanger includes a first heat exchange section and a second heat exchange section that exchanges heat with the first heat exchange section. The first heat exchanger is connected to a first end of the first heat exchange section, the second end of the first heat exchange section is connected to a first end of the cooling electronic expansion valve, the second end of the cooling electronic expansion valve is connected to the first valve, the second end of the first heat exchange section is connected to a first end of the gas-replenishing electronic expansion valve, the second heat exchange section is connected between the second end of the gas-replenishing electronic expansion valve and the gas-replenishing port of the compressor, and the heating electronic expansion valve is connected between the second end of the first heat exchange section and the first heat exchanger. The refrigerant recovery device includes: The control unit is used to control the direct cooling system to enter the refrigerant recovery mode when a refrigerant recovery command is received: controlling the compressor's operating frequency to adjust to a preset frequency, controlling the fan to run at full speed, adjusting the opening of the refrigeration electronic expansion valve according to the suction superheat, controlling the heating electronic expansion valve to close, and controlling the gas replenishment electronic expansion valve to close, wherein the refrigerant flows from the first heat exchanger to the second heat exchanger through the first valve, and from the second heat exchanger to the compressor through the second valve; The first processing unit is configured to instruct the first valve to close when the first system pipeline pressure at the outlet of the compressor is less than a first preset pressure, and the operating time of the compressor in the refrigerant recovery mode is greater than a first preset time. The second processing unit is used to instruct the second valve to close and control the compressor to decelerate when the pressure in the second system pipeline at the compressor inlet is less than the second preset pressure, and to control the compressor to stop after a second preset time period following the instruction to close the second valve.

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