Fluorine pump compression refrigeration system and control method thereof

Abstract

The invention provides a fluorine pump compression refrigerating system and a control method thereof.The system comprises an evaporator, a condenser and a throttling element, the throttling element is connected between an outlet of the condenser and an inlet of the evaporator, a liquid storage tank is connected between the condenser and the throttling element, and the fluorine pump compression refrigerating system further comprises a refrigerant adjusting tank; the top of the refrigerant adjusting tank is in controllable on-off communication with an outlet of the condenser through a first pipeline, and the bottom of the refrigerant adjusting tank is in controllable on-off communication with the top of the liquid storage tank through a second pipeline or is in controllable on-off communication with a liquid inlet of the throttling element through the second pipeline. By controlling the on-off duration of the first pipeline and the second pipeline or the pipe inner diameters of the two pipelines, control over the amount of refrigerant entering and exiting the refrigerant adjusting tank is achieved, migration of the refrigerant is achieved, and accumulated liquid retention in the system due to the fact that the filling amount of the refrigerant in the system is too large is effectively prevented; excessive refrigerants in the refrigerating system are prevented from occupying a heat exchange pipeline in the heat exchanger, and the heat exchange efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of air conditioning, and in particular relates to a fluorine pump compression refrigeration system and a control method thereof. Background Art

[0002] With the extensive application of 4G and the gradual popularization of 5G, the heat generated by various data processing equipment is getting higher and higher, and data centers have higher and higher requirements for the cooling capacity and energy saving of air-conditioning equipment.

[0003] Using outdoor natural cold sources in transitional seasons and cold winters to cool the data center can significantly reduce the operating costs of air conditioning equipment. A common method is to use fluorine pump air conditioning, enable the fluorine pump mode in winter, stop the operation of the compressor, and use the fluorine pump to drive the refrigerant to achieve heat pipe refrigeration operation, which greatly reduces the operating costs of the equipment. The fluorine pump compression refrigeration system is a composite system. The fluorine pump heat pipe system and the compression refrigeration system share the evaporator and condenser, as well as some common refrigerant pipelines, system components, etc.

[0004] Since the heat load of the data center fluctuates with user usage and seasonal changes, more and more computer room air conditioners now use variable frequency technology to cope with the heat load fluctuations of the data center and ensure the constant temperature and humidity requirements of the data center. However, the change in the compressor frequency of the refrigeration system will cause the optimal refrigerant circulation volume to change. Generally, the higher the frequency, the greater the refrigerant circulation volume required. If the optimal refrigerant injection volume at 100% load is guaranteed during the design and development of the refrigeration system, the optimal refrigerant injection volume at 75% or 50% load or other low-frequency operation conditions will be relatively small. Therefore, the refrigerant inside the unit may accumulate liquid under low-frequency conditions, and the accumulated liquid is retained at the bottom of the heat exchanger, which is not conducive to heat exchange.

[0005] At the same time, in the fluorine pump mode, considering the liquid height requirement at the suction port of the fluorine pump, the required refrigerant filling amount is usually large in the fluorine pump mode. Therefore, the fluorine pump compression refrigeration system is likely to form refrigerant liquid retention under actual operating conditions. It is necessary to consider migrating the retained refrigerant to the liquid storage tank, and in the high-frequency compression refrigeration mode or the fluorine pump refrigeration mode, the refrigerant liquid retained in the liquid storage tank should be released as soon as possible to participate in the system circulation operation. Summary of the invention

[0006] Therefore, the present invention provides a fluorine pump compression refrigeration system and a control method thereof, which can solve the technical problem of refrigerant redundancy caused by the difference in refrigerant filling amount required under different operating conditions of the fluorine pump compression refrigeration system in the prior art.

[0007] In order to solve the above problems, the present invention provides a fluorine pump compression refrigeration system, comprising an evaporator, a condenser and a throttling element, wherein the throttling element is connected between the outlet of the condenser and the inlet of the evaporator, and a liquid storage tank is connected between the condenser and the throttling element. The fluorine pump compression refrigeration system also includes a refrigerant regulating tank, the top of the refrigerant regulating tank is controllably connected to the outlet of the condenser through a first pipeline, and the bottom of the refrigerant regulating tank is controllably connected to the top of the liquid storage tank through a second pipeline or controllably connected to the liquid inlet of the throttling element through the second pipeline.

[0008] In some embodiments, an electromagnetic on-off valve is connected in series to the second pipeline; and / or the bottom height of the refrigerant regulating tank is higher than the top height of the liquid storage tank, so that the refrigerant in the refrigerant regulating tank can flow into the liquid storage tank under the action of its own weight.

[0009] In some embodiments, the fluorine pump compression refrigeration system also includes a flow switching valve, which has a first state connecting the outlet of the condenser with the top of the refrigerant regulating tank and a second state connecting the outlet of the condenser with the top of the liquid storage tank. The flow switching valve can be controlled to switch between the first state and the second state to achieve controllable on-off connection between the first pipeline and the outlet of the condenser.

[0010] In some embodiments, the fluorine pump compression refrigeration system also includes a fluorine pump, the liquid inlet of the fluorine pump is connected to the bottom of the liquid storage tank, the liquid outlet of the fluorine pump is connected to the liquid inlet of the throttling element, and a third pipeline is also connected between the liquid inlet of the fluorine pump and the liquid inlet of the throttling element, a first one-way valve is connected in series on the third pipeline, and the one-way conduction direction of the first one-way valve is from the liquid inlet side of the fluorine pump to the liquid inlet side of the throttling element; and / or the flow path switching valve is an electromagnetic three-way valve.

[0011] In some embodiments, the fluorine pump compression refrigeration system also includes a compressor and a fourth pipeline, the air intake of the compressor is connected to the air outlet of the evaporator, the air exhaust of the compressor is connected to the air inlet of the condenser, the fourth pipeline is connected between the air intake and exhaust ports of the compressor, and a second one-way valve is connected in series on the fourth pipeline, and the one-way conduction direction of the second one-way valve is from the air intake side of the compressor to the air exhaust side of the compressor.

[0012] In some embodiments, a liquid level gauge is provided in the refrigerant regulating tank for detecting the real-time liquid level height of the refrigerant in the refrigerant regulating tank; and / or a temperature sensor is provided in the refrigerant regulating tank for detecting the real-time temperature of the refrigerant in the refrigerant regulating tank.

[0013] The present invention also provides a control method for the fluorine pump compression refrigeration system as described above, comprising the following steps:

[0014] Obtaining the operating mode of the fluorine pump compression refrigeration system;

[0015] The on-off of the electromagnetic on-off valve, the state switching of the flow path switching valve, and the start and stop of the compressor and the fluorine pump are controlled according to the operation mode.

[0016] In some embodiments, when the operating mode is the fluorine pump refrigeration mode, the electromagnetic on-off valve is controlled to be turned on, the flow path switching valve is controlled to be in the first state, the compressor is controlled to stop running or remain in a stopped state, and the fluorine pump is controlled to operate after the refrigerant in the refrigerant regulating tank completely flows into the liquid storage tank.

[0017] In some embodiments, when the operating mode is a compression refrigeration mode, the compressor is controlled to operate and the real-time operating frequency of the compressor is obtained, and the target liquid level height h of the refrigerant in the refrigerant regulating tank corresponding to the real-time operating frequency is obtained according to the obtained real-time operating frequency, and the on-off of the electromagnetic on-off valve and the state switching of the flow switching valve are controlled to adjust the real-time liquid level height of the refrigerant in the refrigerant regulating tank to the target liquid level height h.

[0018] In some embodiments, when the real-time liquid level of the refrigerant in the refrigerant regulating tank is lower than the target liquid level h, the electromagnetic on-off valve is controlled to be turned on, the flow path switching valve is controlled to be in the first state, and the on-time of the electromagnetic on-off valve is controlled to be shorter than the maintenance time of the first state, until the real-time liquid level rises to the target liquid level h, the flow path switching valve is controlled to switch to the second state, and the electromagnetic on-off valve is controlled to be turned off; or,

[0019] When the real-time liquid level of the refrigerant in the refrigerant regulating tank is higher than the target liquid level h, the electromagnetic on-off valve is controlled to be connected, the flow switching valve is controlled to be in the first state, and the conduction time of the electromagnetic on-off valve is controlled to be longer than the maintenance time of the first state, until the real-time liquid level drops to the target liquid level h, the flow switching valve is controlled to switch to the second state, and the electromagnetic on-off valve is controlled to be disconnected.

[0020] In some embodiments, the target liquid level height h is obtained by:

[0021] Obtaining the optimal refrigerant filling amount m1 of the system cycle corresponding to the real-time operating frequency, and calculating the refrigerant amount m2 to be stored in the refrigerant regulating tank, m2=m-m1, where m is the total refrigerant amount in the system;

[0022] Acquire the real-time temperature t and / or the real-time saturation pressure in the refrigerant regulating tank, and acquire the liquid refrigerant density ρ corresponding to the real-time temperature t and / or the real-time saturation pressure according to the refrigerant parameters pre-stored in the controller;

[0023] The target liquid level height h is calculated according to the formula h=m2 / (ρS), where S is the cross-sectional area of ​​the storage space of the refrigerant regulating tank.

[0024] The fluorine pump compression refrigeration system and control method thereof provided by the present invention have the following beneficial effects:

[0025] The amount of refrigerant entering and exiting the refrigerant regulating tank can be controlled by controlling the on-off time of the first pipeline and the second pipeline or the inner diameter of the two pipelines, thereby achieving the migration and replenishment of the refrigerant stored in the refrigerant regulating tank to the system circulation, increasing the refrigerant filling amount of the system circulation, or achieving the migration and storage of excess refrigerant in the system circulation in the refrigerant regulating tank, effectively preventing the system from being filled with too much refrigerant and causing liquid accumulation in the system, preventing the existence of excessive refrigerant in the refrigeration system from occupying the heat exchange pipes in the heat exchanger, and improving the heat exchange efficiency; in this way, the technical solution of the present invention realizes the controllable adjustment of the refrigerant circulation amount required in the refrigeration system, meets the requirements of the optimal system circulation amount, and solves the refrigerant redundancy problem caused by the difference in the refrigerant filling amount required under different operating conditions of the fluorine pump compression refrigeration system in the prior art, so as to meet the optimal circulation amount required by the refrigeration system under various operating conditions as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0027] Figure 1 2 is a schematic diagram of the principle of a fluorine pump compression refrigeration system according to an embodiment of the present invention;

[0028] Figure 2 It is a schematic diagram of the principle of a fluorine pump compression refrigeration system according to another embodiment of the present invention.

[0029] The accompanying drawings are marked as follows:

[0030] 11. Evaporator; 111. Internal fan; 12. Condenser; 121. External fan; 13. Throttling element; 14. Liquid storage tank; 15. Fluorine pump; 16. Compressor; 2. Refrigerant regulating tank; 21. Liquid level gauge; 3. Flow path switching valve; 101. First pipeline; 102. Second pipeline; 1021. Solenoid on-off valve; 103. Third pipeline; 1031. First one-way valve; 104. Fourth pipeline; 1041. Second one-way valve. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0033] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90° or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0034] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0035] See also Figure 1 and Figure 2 As shown, according to an embodiment of the present invention, a fluorine pump compression refrigeration system is provided, comprising an evaporator 11, a condenser 12 and a throttling element 13 (such as an electronic expansion valve), wherein the throttling element 13 is connected between the outlet of the condenser 12 and the inlet of the evaporator 11, and a liquid storage tank 14 is connected between the condenser 12 and the throttling element 13. The fluorine pump compression refrigeration system also includes a refrigerant regulating tank 2, the top of the refrigerant regulating tank 2 is controllably connected to the outlet of the condenser 12 through a first pipeline 101, and the bottom of the refrigerant regulating tank 2 is controllably connected to the top of the liquid storage tank 14 through a second pipeline 102 or controllably connected to the liquid inlet of the throttling element 13 through the second pipeline 102. It can be understood that the top of the refrigerant regulating tank 2 is the top space in the tank, and generally speaking, the top space contains gaseous refrigerant, and the top of the liquid storage tank 14 is the top space in the tank, and generally speaking, the top space contains gaseous refrigerant.

[0036] In this technical solution, the amount of refrigerant entering and exiting the refrigerant regulating tank 2 can be controlled by controlling the on-off time of the first pipeline 101 and the second pipeline 102 or the inner diameter of the two pipelines, thereby achieving the migration and replenishment of the refrigerant stored in the refrigerant regulating tank 2 to the system circulation, increasing the refrigerant filling amount of the system circulation, or achieving the migration and storage of excess refrigerant in the system circulation in the refrigerant regulating tank 2, effectively preventing the excessive refrigerant filling amount in the system from causing liquid accumulation in the system, preventing the existence of excessive refrigerant in the refrigeration system from occupying the heat exchange pipes in the heat exchanger, and improving the heat exchange efficiency; in this way, the technical solution of the present invention realizes the controllable adjustment of the refrigerant circulation amount required in the refrigeration system, meets the optimal system circulation amount requirements, and solves the refrigerant redundancy problem caused by the difference in the refrigerant filling amount required under different operating conditions of the fluorine pump compression refrigeration system in the prior art, so as to try to meet the optimal circulation amount required by the refrigeration system under various operating conditions.

[0037] In a specific embodiment, an electromagnetic on-off valve 1021 is connected in series to the second pipeline 102, so that the second pipeline 102 can be opened and closed by controlling the power on and off of the electromagnetic on-off valve 1021. The control is simple and the implementation cost is low. In a preferred embodiment, the electromagnetic on-off valve 1021 is a normally closed valve when the power is on, that is, it is open for flow when the power is on, and it is closed for flow when the power is off.

[0038] In another preferred embodiment, the bottom height of the refrigerant regulating tank 2 is higher than the top height of the liquid storage tank 14 , so that the refrigerant in the refrigerant regulating tank 2 can flow into the liquid storage tank 14 under the action of its own weight.

[0039] In this technical solution, the refrigerant regulating tank 2 is set at a higher position. When the electromagnetic on-off valve 1021 in the second pipeline 102 is controlled to open and circulate, the liquid refrigerant in the refrigerant regulating tank 2 will enter the liquid storage tank 14 set at a lower position under the action of its own weight, thereby increasing the amount of refrigerant in the system cycle. It should be noted that in this technical solution, only the relative height difference between the refrigerant regulating tank 2 and the liquid storage tank 14 is used to realize the migration by the self-weight of the liquid refrigerant. The structure is particularly simple, and no other targeted configuration of pumping structures is required, further reducing the manufacturing cost.

[0040] In some embodiments, the fluorine pump compression refrigeration system also includes a flow switching valve 3, which has a first state connecting the outlet of the condenser 12 with the top of the refrigerant regulating tank 2 and a second state connecting the outlet of the condenser 12 with the top of the liquid storage tank 14. The flow switching valve 3 can be controlled to switch between the first state and the second state to achieve controllable on-off connection between the first pipeline 101 and the outlet of the condenser 12.

[0041] In this technical solution, when the flow switching valve 3 is in the first state, the refrigerant (mainly liquid) flowing out of the condenser 12 is introduced into the refrigerant regulating tank 2. At this time, the electromagnetic on-off valve 1021 is controlled to be in the on state to ensure the smooth outflow or storage of the liquid refrigerant in the refrigerant regulating tank 2. When the flow switching valve 3 is in the second state, the refrigerant flowing out of the condenser 12 is guided to the liquid storage tank 14 to participate in the system circulation. At this time, the electromagnetic on-off valve 1021 can be in the cut-off state.

[0042] Generally speaking, any valve component and valve assembly that can realize the switching between the first state and the second state can be called the aforementioned flow path switching valve 3 of the present invention, for example, it can be realized by a combination of multiple two-way valves. As a preferred embodiment, the flow path switching valve 3 is a three-way valve, specifically a two-position three-way solenoid valve, which can significantly simplify the system design. Figure 1 and Figure 2As shown, when the two-position three-way solenoid valve is energized, OM is closed and ON is connected, and when the power is off, OM is connected and ON is closed. Since the redundancy of adjusting the refrigerant through the refrigerant regulating tank 2 is relatively rare and the time required is relatively short, and the refrigerant in the refrigerant regulating tank 2 needs to be migrated to the liquid storage tank 14 or the system to participate in the circulation in the fluorine pump refrigeration mode, the probability of the three-way valve ON channel opening is relatively small / the probability of the OM channel opening is very high. Therefore, the preferred three-way valve is to use OM connected and ON closed when the power is off, which can save electricity and increase the service life of the three-way valve.

[0043] In some embodiments, the fluorine pump compression refrigeration system also includes a fluorine pump 15, the liquid inlet of the fluorine pump 15 is connected to the bottom of the liquid storage tank 14, the liquid outlet of the fluorine pump 15 is connected to the liquid inlet of the throttling element 13, and a third pipeline 103 is also connected between the liquid inlet of the fluorine pump 15 and the liquid inlet of the throttling element 13, and a first one-way valve 1031 is connected in series to the third pipeline 103, and the one-way conduction direction of the first one-way valve 1031 is from the liquid inlet side of the fluorine pump 15 to the liquid inlet side of the throttling element 13. It can be understood that when the fluorine pump 15 is running, the first one-way valve 1031 will cut off the circulation of the refrigerant by the third pipeline 103 under the action of the reverse pressure difference.

[0044] In this technical solution, the third pipeline 103 connected in parallel with the fluorine pump 15 can realize the automatic switching between the compression refrigeration mode and the fluorine pump refrigeration mode of the fluorine pump compression refrigeration system of the present invention, and the structure is simple and easy to operate.

[0045] In some embodiments, the fluorine pump compression refrigeration system further includes a compressor 16 and a fourth pipeline 104, the air intake of the compressor 16 is communicated with the air outlet of the evaporator 11, the air outlet of the compressor 16 is communicated with the air inlet of the condenser 12, the fourth pipeline 104 is connected between the air intake and the air outlet of the compressor 16, and a second one-way valve 1041 is serially connected to the fourth pipeline 104, and the one-way conduction direction of the second one-way valve 1041 is from the air intake side of the compressor 16 to the air outlet side of the compressor 16. When the compressor 16 is running, the second one-way valve 1041 will cut off the circulation of the refrigerant in the fourth pipeline 104 under the action of the reverse pressure difference.

[0046] In some embodiments, a liquid level meter 21 is provided in the refrigerant regulating tank 2 for detecting the real-time liquid level height of the refrigerant in the refrigerant regulating tank 2; and / or, a temperature sensor (not shown in the figure) is provided in the refrigerant regulating tank 2 for detecting the real-time temperature of the refrigerant in the refrigerant regulating tank 2.

[0047] In this way, it can be understood that, compared with the fluorine pump compression refrigeration system in the related art, the technical solution of the present invention only needs to add 1 solenoid valve (that is, the aforementioned solenoid on-off valve 1021), 1 three-way valve (that is, the aforementioned solenoid three-way valve) and 1 regulating tank (that is, the aforementioned refrigerant regulating tank 2), so as to realize redundant regulation of the refrigerant. In the compression refrigeration mode, if the ON channel opening time of the three-way valve (that is, the maintenance time of the first state) is greater than the opening time of the solenoid valve, the excess refrigerant can be stored in the regulating tank at a high place to prevent the existence of excessive refrigerant in the refrigeration system from invading the heat exchange pipe in the heat exchanger. On the contrary, the refrigerant in the regulating tank can be migrated out to supplement the liquid storage tank or the system to participate in the circulation; in the fluorine pump refrigeration mode, the solenoid valve is opened to use gravity to migrate the refrigerant in the regulating tank back to the liquid storage tank or the system to participate in the circulation, so as to ensure that there is enough refrigerant liquid height in the liquid storage tank to prevent the pressure at the suction end of the fluorine pump from being too low to cause cavitation of the fluorine pump. This technical solution can regulate the redundant refrigerant accurately and reliably, making full use of the on-off time difference control of the three-way valve and the solenoid valve and the effect of liquid gravity, requiring only a few additional parts and the connection pipelines are simple.

[0048] It should be noted that, see Figure 1 The second pipe 102 in the figure is connected to the top area of ​​the liquid storage tank 14, which can achieve the purpose of moving the refrigerant in the refrigerant regulating tank 2 of the present invention out or into the refrigerant, but this requires necessary changes to the structure of the liquid storage tank 14 in the prior art, and the cost of the modification is relatively high. Figure 2 As shown, the second pipeline 102 in the figure is connected with the pipeline between the first one-way valve 1031 and the throttling element 13. In the specific implementation, only a three-way pipe is added, and there is no need to change the structure of the liquid storage tank 14. It is simpler and easier to operate with lower cost.

[0049] According to an embodiment of the present invention, there is also provided a control method for the fluorine pump compression refrigeration system as described above, comprising the following steps:

[0050] Obtaining the operating mode of the fluorine pump compression refrigeration system;

[0051] The on-off of the electromagnetic on-off valve 1021 , the state switching of the flow path switching valve 3 , and the start and stop of the compressor 16 and the fluorine pump 15 are controlled according to the operation mode.

[0052] Specifically, when the operating mode is the fluorine pump refrigeration mode, the electromagnetic on-off valve 1021 is controlled to be turned on, the flow path switching valve 3 is controlled to be in the first state, the compressor 16 is controlled to stop running or remain in a stopped state, and after the refrigerant in the refrigerant regulating tank 2 completely flows into the liquid storage tank 14, the electromagnetic on-off valve 1021 is controlled to be cut off and the fluorine pump 15 is controlled to operate.

[0053] That is, when the system is running the fluorine pump refrigeration mode, before controlling the operation of the fluorine pump 15, the electromagnetic on-off valve 1021 is first controlled to be turned on, and the flow path switching valve 3 is controlled to be in the first state, so that the liquid refrigerant in the refrigerant regulating tank 2 is completely transferred back to the liquid storage tank 14 under the action of its own weight, and then the fluorine pump 15 is controlled to operate the fluorine pump refrigeration mode, so that it can ensure that there is enough refrigerant liquid height in the liquid storage tank 14 to prevent the pressure at the suction end (i.e., the liquid inlet) of the fluorine pump 15 from being too low to cause fluorine pump cavitation. When the fluorine pump 15 is running, it is preferred that the flow path switching valve 3 is switched to the second state (for example, the power is turned off), and the electromagnetic on-off valve 1021 is turned off to cut off the flow.

[0054] In some embodiments, when the operating mode is a compression refrigeration mode, the compressor 16 is controlled to operate and the real-time operating frequency of the compressor 16 is obtained, and the target liquid level height h of the refrigerant in the refrigerant regulating tank 2 corresponding to the real-time operating frequency is obtained according to the obtained real-time operating frequency, and the electromagnetic on-off valve 1021 and the state switching of the flow path switching valve 3 are controlled to adjust the real-time liquid level height of the refrigerant in the refrigerant regulating tank 2 to the target liquid level height h.

[0055] In this technical solution, when the system operates in compression refrigeration mode, the corresponding target liquid level height h is obtained according to the real-time operating frequency of the compressor 16 and the real-time liquid level height of the refrigerant in the refrigerant regulating tank 2 is controlled and adjusted to be at the corresponding target liquid level height h, thereby ensuring that the refrigerant filling amount in the system matches each real-time operating frequency, that is, they are all at the optimal filling amount, meeting the better system circulation volume requirements.

[0056] Specifically, when the real-time liquid level of the refrigerant in the refrigerant regulating tank 2 is lower than the target liquid level h, it indicates that the refrigerant circulating in the system is too much. At this time, the electromagnetic on-off valve 1021 is controlled to be turned on, the flow path switching valve 3 is controlled to be in the first state, and the on-time of the electromagnetic on-off valve 1021 is controlled to be shorter than the maintenance time of the first state, so as to utilize the principle of more in and less out to move the excess refrigerant in the system cycle into the refrigerant regulating tank 2 for storage, until the real-time liquid level rises to the target liquid level h, the flow path switching valve 3 is controlled to switch to the second state, and the electromagnetic on-off valve 1021 is controlled to be disconnected, so as to prevent the excessive amount of refrigerant circulating in the system from causing liquid accumulation, thereby improving the heat exchange efficiency; or,

[0057] When the real-time liquid level of the refrigerant in the refrigerant regulating tank 2 is higher than the target liquid level h, it indicates that the refrigerant circulating in the system is too little. At this time, the electromagnetic on-off valve 1021 is controlled to be connected, the flow switching valve 3 is controlled to be in the first state, and the conduction time of the electromagnetic on-off valve 1021 is controlled to be longer than the maintenance time of the first state, so as to utilize the principle of less in and more out to release the refrigerant stored in the refrigerant regulating tank 2 to participate in the system circulation, thereby increasing the refrigerant filling amount of the system, until the real-time liquid level drops to the target liquid level h, the flow switching valve 3 is controlled to switch to the second state, and the electromagnetic on-off valve 1021 is controlled to be disconnected.

[0058] In this way, dynamic adjustment of the refrigerant in the system under the compression refrigeration mode is achieved, which can ensure that the refrigerant injection amount in the system meets the optimal system circulation volume requirements.

[0059] In some embodiments, the target liquid level height h is obtained by: obtaining the optimal refrigerant filling amount m1 of the system cycle corresponding to the real-time operating frequency (specifically pre-stored in the controller), and calculating the refrigerant amount m2 to be stored in the refrigerant regulating tank 2, m2=m-m1, where m is the total refrigerant amount in the system; obtaining the real-time temperature t and / or real-time saturation pressure in the refrigerant regulating tank 2, and obtaining the liquid refrigerant density ρ corresponding to the real-time temperature t and / or real-time saturation pressure according to the refrigerant parameters pre-stored in the controller; calculating the target liquid level height h according to the formula h=m2 / (ρS), where S is the cross-sectional area of ​​the storage space of the refrigerant regulating tank 2, and the aforementioned physical parameters can all be expressed in international units. In a specific embodiment, the refrigerant regulating tank 2 is a cylinder with equal upper and lower diameters, that is, each cross-sectional area S is equal, which can further simplify the acquisition of h.

[0060] In this technical solution, the optimal refrigerant filling amount m1 corresponding to the real-time operating frequency pre-stored in the controller is obtained to reversely infer the refrigerant amount m2 that should be stored in the refrigerant regulating tank 2, and then the corresponding target liquid level height is calculated through relevant physical parameters, which is simple and reliable.

[0061] The following combination Figure 1 The technical solution of the present invention is further described:

[0062] A) Compression refrigeration mode - the fluorine pump (i.e. the aforementioned fluorine pump 15, hereinafter the same) is turned off, and the compressor (i.e. the aforementioned compressor 16, hereinafter the same) is turned on, because the second one-way valve 1041 cannot be conducted due to the reverse pressure difference at both ends at this time; the main circulation flow path of the refrigerant is: compressor → condenser (i.e. the aforementioned condenser 12, hereinafter the same) → three-way valve OM (i.e. the aforementioned second state, hereinafter the same) → liquid storage tank (i.e. the aforementioned liquid storage tank 14, hereinafter the same) → first one-way valve 1031 → throttle valve → evaporator → compressor.

[0063] In the compression refrigeration mode, when the compressor frequency is reduced, the required system circulation volume is usually reduced, and some of the excess refrigerant needs to be transferred to the regulating tank: power is turned on to open the ON channel of the three-way valve (that is, the aforementioned first state, the same below) / close the OM channel for a duration of t1, and then the solenoid valve (that is, the aforementioned solenoid on-off valve 1021, the same below) is opened for a duration of t2<t1. When the liquid level in the regulating tank reaches a height h (that is, the aforementioned target liquid level height h, the same below), the three-way valve and the solenoid valve are powered off to close the ON channel, so that the refrigerant liquid at the condenser outlet re-enters the storage tank through the OM channel. Liquid tank, completes the regulation and control of the refrigerant; when the compressor frequency increases, the required system circulation volume usually increases, and part of the refrigerant in the regulating tank needs to be migrated out to participate in the system circulation: open the solenoid valve for a duration of t3, and then power on to open the ON channel of the three-way valve for a duration of t4<t3. The refrigerant liquid in the regulating tank flows into the liquid storage tank or returns to the system through the solenoid valve under the action of gravity to participate in the circulation. When the liquid level height h in the regulating tank drops to the corresponding high frequency of the compressor, the solenoid valve is closed and the ON channel of the three-way valve is closed / the OM channel is opened to complete the migration control of the refrigerant.

[0064] B) Fluorine pump refrigeration mode - the fluorine pump is turned on, the compressor is turned off, and the three-way valve is powered off to open the OM channel / close the ON channel, because there is a reverse pressure difference at both ends of the first one-way valve 1031 and it cannot be conducted; the main circulation flow path of the refrigerant is: fluorine pump → throttle valve → evaporator → second one-way valve 1041 → condenser → three-way valve OM → liquid storage tank → fluorine pump.

[0065] Since the fluorine pump mode requires the largest amount of refrigerant filling (as explained in the background technology, the main reason is to increase the liquid level height in the liquid storage tank, ensure the safety of the fluorine pump's liquid suction and avoid cavitation of the fluorine pump), it is necessary to migrate all the refrigerant liquid in the regulating tank to the system to participate in the circulation. At this time, the solenoid valve is powered on to open the ON channel / close the OM channel of the three-way valve. The refrigerant liquid in the regulating tank enters the liquid storage tank or the system's pipeline under the action of gravity to participate in the circulation. When the liquid level meter and / or liquid level sensor detects that the liquid level height h in the regulating tank is 0, the solenoid valve is powered off to close the ON channel / open the OM channel to complete the migration control of the refrigerant liquid in the regulating tank, and then the fluorine pump is turned on to run the fluorine pump refrigeration mode.

[0066] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A fluorine pump compression refrigeration system, comprising an evaporator (11), a condenser (12) and a throttling element (13), wherein the throttling element (13) is connected between the outlet of the condenser (12) and the inlet of the evaporator (11), and a liquid storage tank (14) is connected between the condenser (12) and the throttling element (13), characterized in that: It also comprises a refrigerant regulating tank (2), the top of the refrigerant regulating tank (2) being controllably connected to the outlet of the condenser (12) via a first pipeline (101), and the bottom of the refrigerant regulating tank (2) being controllably connected to the top of the liquid storage tank (14) via a second pipeline (102) or being controllably connected to the liquid inlet of the throttling element (13) via the second pipeline (102).

2. The fluorine pump compression refrigeration system according to claim 1, characterized in that: An electromagnetic on-off valve (1021) is serially connected to the second pipeline (102); and / or the bottom height of the refrigerant regulating tank (2) is higher than the top height of the liquid storage tank (14), so that the refrigerant in the refrigerant regulating tank (2) can flow into the liquid storage tank (14) under the action of its own weight.

3. The fluorine pump compression refrigeration system according to claim 2, characterized in that: It also includes a flow path switching valve (3), which has a first state in which the outlet of the condenser (12) is connected to the top of the refrigerant regulating tank (2) and a second state in which the outlet of the condenser (12) is connected to the top of the liquid storage tank (14). The flow path switching valve (3) can be controlled to switch between the first state and the second state so as to achieve controllable on-off connection between the first pipeline (101) and the outlet of the condenser (12).

4. The fluorine pump compression refrigeration system according to claim 3, characterized in that: It also includes a fluorine pump (15), the liquid inlet of the fluorine pump (15) is connected to the bottom of the liquid storage tank (14), the liquid outlet of the fluorine pump (15) is connected to the liquid inlet of the throttling element (13), and a third pipeline (103) is connected between the liquid inlet of the fluorine pump (15) and the liquid inlet of the throttling element (13), and a first one-way valve (1031) is connected in series to the third pipeline (103), and the one-way conduction direction of the first one-way valve (1031) is from the liquid inlet side of the fluorine pump (15) to the liquid inlet side of the throttling element (13); and / or the flow path switching valve (3) is an electromagnetic three-way valve.

5. The fluorine pump compression refrigeration system according to claim 4, characterized in that: It also includes a compressor (16) and a fourth pipeline (104), wherein the air intake port of the compressor (16) is connected to the air outlet port of the evaporator (11), and the air outlet port of the compressor (16) is connected to the air inlet port of the condenser (12); the fourth pipeline (104) is connected between the air intake port and the air outlet port of the compressor (16), and a second one-way valve (1041) is connected in series to the fourth pipeline (104); the one-way conduction direction of the second one-way valve (1041) is from the air intake port side of the compressor (16) to the air outlet side of the compressor (16).

6. The fluorine pump compression refrigeration system according to claim 1, characterized in that: The refrigerant regulating tank (2) is provided with a liquid level meter (21) for detecting the real-time liquid level height of the refrigerant in the refrigerant regulating tank (2); and / or the refrigerant regulating tank (2) is provided with a temperature sensor for detecting the real-time temperature of the refrigerant in the refrigerant regulating tank (2).

7. A control method for a fluorine pump compression refrigeration system as claimed in claim 5, characterized in that: The steps include: Obtaining the operating mode of the fluorine pump compression refrigeration system; The on-off of the electromagnetic on-off valve (1021), the state switching of the flow path switching valve (3), and the start and stop of the compressor (16) and the fluorine pump (15) are controlled according to the operation mode.

8. The control method according to claim 7, characterized in that: When the operation mode is the fluorine pump refrigeration mode, the electromagnetic on-off valve (1021) is controlled to be turned on, the flow path switching valve (3) is controlled to be in the first state, the compressor (16) is controlled to stop running or remain in a stopped state, and the fluorine pump (15) is controlled to operate after the refrigerant in the refrigerant regulating tank (2) completely flows into the liquid storage tank (14).

9. The control method according to claim 7, characterized in that: When the operation mode is the compression refrigeration mode, the compressor (16) is controlled to operate and the real-time operation frequency of the compressor (16) is obtained. The target liquid level height h of the refrigerant in the refrigerant regulating tank (2) corresponding to the real-time operation frequency is obtained based on the obtained real-time operation frequency. The electromagnetic on-off valve (1021) is controlled to be on and off, and the state of the flow path switching valve (3) is switched so that the real-time liquid level height of the refrigerant in the refrigerant regulating tank (2) is adjusted to the target liquid level height h.

10. The control method according to claim 9, characterized in that: When the real-time liquid level of the refrigerant in the refrigerant regulating tank (2) is lower than the target liquid level h, the electromagnetic on-off valve (1021) is controlled to be turned on, the flow path switching valve (3) is controlled to be in the first state, and the on-time of the electromagnetic on-off valve (1021) is controlled to be shorter than the maintenance time of the first state, until the real-time liquid level rises to the target liquid level h, the flow path switching valve (3) is controlled to switch to the second state, and the electromagnetic on-off valve (1021) is controlled to be turned off; or, When the real-time liquid level of the refrigerant in the refrigerant regulating tank (2) is higher than the target liquid level h, the electromagnetic on-off valve (1021) is controlled to be connected, the flow path switching valve (3) is controlled to be in the first state, and the conduction time of the electromagnetic on-off valve (1021) is controlled to be longer than the maintenance time of the first state, until the real-time liquid level drops to the target liquid level h, the flow path switching valve (3) is controlled to switch to the second state, and the electromagnetic on-off valve (1021) is controlled to be disconnected.

11. The control method according to claim 9, characterized in that: The target liquid level height h is obtained by: Obtaining the optimal refrigerant filling amount m1 of the system cycle corresponding to the real-time operating frequency, and calculating the amount of refrigerant m2 to be stored in the refrigerant regulating tank (2), m2=m-m1, where m is the total amount of refrigerant in the system; Acquiring the real-time temperature t and / or the real-time saturation pressure in the refrigerant regulating tank (2), and obtaining the liquid refrigerant density ρ corresponding to the real-time temperature t and / or the real-time saturation pressure according to the refrigerant parameters pre-stored in the controller; The target liquid level height h is calculated according to the formula h=m2 / (ρS), wherein S is the cross-sectional area of ​​the storage space of the refrigerant regulating tank (2).

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