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, a fluorine pump 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 communicates with the top of the liquid storage tank through a first pipeline, the bottom of the refrigerant adjusting tank communicates with the top of the liquid storage tank through a second pipeline in a controllable on-off mode, and the fluorine pump can pump the liquid refrigerant in the liquid storage tank into the refrigerant adjusting tank to be stored in the refrigerant adjusting tank. The redundant refrigerant can be accurately and reliably adjusted, when the system operates in the compression refrigeration mode, the fluorine pump which is idle and does not work is used for transferring and storing the redundant liquid refrigerant into the refrigerant adjusting tank, and the situation that excessive refrigerant exists in the refrigeration system and occupies a heat exchange pipeline in a heat exchanger is prevented.

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, a fluorine pump 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 connected to the top of the liquid storage tank 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. The fluorine pump can pump the liquid refrigerant in the liquid storage tank into the refrigerant regulating tank for storage.

[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 in which the liquid outlet of the fluorine pump is connected to the bottom of the refrigerant regulating tank and a second state in which the liquid outlet of the fluorine pump is connected to the liquid inlet of the throttling element. The flow switching valve can be controlled to switch between the first state and the second state. The liquid inlet of the fluorine pump is connected to the bottom of the liquid storage tank, 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. 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.

[0010] In some embodiments, 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 second state, the compressor is controlled to stop running or remain in a stopped state, and after the refrigerant in the refrigerant regulating tank completely flows into the liquid storage tank, the electromagnetic on-off valve is controlled to be cut off and the fluorine pump is controlled to operate.

[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, the state switching of the flow switching valve, and the start and stop of the fluorine pump 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 cut off, the flow path switching valve is controlled to be in the first state, and the fluorine pump is controlled to start running, until the real-time liquid level rises to the target liquid level h, and then the fluorine pump is controlled to stop running; 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 path switching valve is controlled to be in the second state, and the fluorine pump is controlled to be in a stopped state, until the real-time liquid level drops to the target liquid level h, and the electromagnetic on-off valve is controlled to be cut off.

[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] When more refrigerant is needed in the system cycle, the second pipeline can be controlled to be connected, so that the liquid refrigerant in the refrigerant regulating tank enters the liquid storage tank to participate in the system cycle, that is, the refrigerant filling amount of the system cycle is increased. When less refrigerant is needed in the system cycle, the fluorine pump can be controlled to operate, so as to migrate part of the liquid refrigerant stored in the liquid storage tank in the system cycle to the refrigerant regulating tank, effectively preventing the system from being filled with too much refrigerant and causing liquid accumulation in the system, thereby improving heat exchange efficiency. The technical solution of the present invention can achieve accurate and reliable regulation of redundant refrigerants. When the system operates in compression refrigeration mode, the idle and non-working fluorine pump is used to migrate and store excess liquid refrigerant in the refrigerant regulating tank, thereby preventing excessive refrigerant in the refrigeration system from occupying the heat exchange pipes in the heat exchanger. Fewer components are used and the connecting pipes are simple. 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 It is a schematic diagram of the principle of the fluorine pump compression refrigeration system of an embodiment of the present invention.

[0028] The accompanying drawings are marked as follows:

[0029] 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

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] See also Figure 1As shown, according to an embodiment of the present invention, a fluorine pump compression refrigeration system is provided, comprising an evaporator 11, a condenser 12, a fluorine pump 15 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 connected to the top of the liquid storage tank 14 through a first pipeline 101, and the bottom of the refrigerant regulating tank 2 is connected to the liquid storage tank 14 through a second pipeline 102. 4 is controllably connected on and off. 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. The top of the liquid storage tank 14 is the top space in the tank, and generally speaking, the top space contains gaseous refrigerant. In this way, the first pipeline 101 also realizes the top bypass of the gaseous refrigerant in the top space of the refrigerant regulating tank 2 and the liquid storage tank 14, while the bottom of the refrigerant regulating tank 2 and the bottom space of the liquid storage tank 14 are liquid refrigerant. The fluorine pump 15 can pump the liquid refrigerant in the liquid storage tank 14 into the refrigerant regulating tank 2 for storage.

[0035] In this technical solution, when more refrigerant is needed in the system cycle, the second pipeline 102 can be controlled to be connected, so that the liquid refrigerant in the refrigerant regulating tank 2 enters the liquid storage tank 14 to participate in the system cycle, that is, the refrigerant filling amount of the system cycle is increased. When the refrigerant required in the system cycle is less, the fluorine pump 15 can be controlled to operate, so that part of the liquid refrigerant stored in the liquid storage tank 14 in the system cycle is migrated to the refrigerant regulating tank 2, effectively preventing the system from being filled with too much refrigerant and causing liquid accumulation in the system, thereby improving the heat exchange efficiency. The technical solution of the present invention can achieve accurate and reliable regulation of redundant refrigerants. When the system operates in the compression refrigeration mode, the idle and non-working fluorine pump 15 is used to migrate and store excess liquid refrigerant in the refrigerant regulating tank 2, so as to prevent the existence of excessive refrigerant in the refrigeration system from occupying the heat exchange pipes in the heat exchanger. Fewer components are used and the connecting pipes are simple.

[0036] It should be noted that, in the technical solution of the present invention, the first pipeline 101 forms a gas bypass between the top spaces of the refrigerant regulating tank 2 and the liquid storage tank 14, which can ensure smooth migration of the liquid refrigerant between the two.

[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 further includes a flow path switching valve 3, the flow path switching valve 3 has a first state of connecting the liquid outlet of the fluorine pump 15 with the bottom of the refrigerant regulating tank 2 and a second state of connecting the liquid outlet of the fluorine pump 15 with the liquid inlet of the throttling element 13, the flow path switching valve 3 can be controlled to switch between the first state and the second state, the liquid inlet of the fluorine pump 15 is connected to the bottom of the liquid storage tank 14, 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, the third pipeline 103 is serially connected with a first check valve 1031, and the one-way conduction direction of the first check 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 check valve 1031 will cut off the circulation of the refrigerant by the third pipeline 103 under the action of the reverse pressure difference.

[0041] 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; at the same time, the fluorine pump 15 can be used for two purposes by switching the flow path switching valve 3. Specifically, when the flow path switching valve 3 is in the first state, the fluorine pump 15 is controlled to operate. The fluorine pump 15 can pump and migrate part of the liquid refrigerant in the liquid storage tank 14 to be stored in the refrigerant regulating tank 2, thereby reducing the refrigerant injection amount in the system and ensuring the heat exchange efficiency. At this time, the system runs in the compression refrigeration mode. It can be understood that there is no need to separately configure the system with a corresponding pumping structure for the migration of the liquid refrigerant to the refrigerant regulating tank 2. Instead, the fluorine pump 15, which is originally idle and not working in the compression refrigeration mode, is utilized, thereby simplifying the system design and reducing the design cost. When the flow path switching valve 3 is in the second state, the fluorine pump 15 is controlled to operate, and the system runs in the fluorine pump refrigeration mode.

[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 As 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 fluorine pump 15 is used to lift the refrigerant liquid to the refrigerant regulating tank 2, the situation is relatively rare and the time required is relatively short. In the compression refrigeration mode, the fluorine pump is mostly in the closed state. At the same time, in the fluorine pump refrigeration mode, the refrigerant at the outlet of the fluorine pump needs to enter the throttle valve through the OM channel. Therefore, the preferred three-way valve is to use OM to be connected and ON to be closed when the power is off, which can reduce power consumption and increase the service life of the three-way valve.

[0043] 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.

[0044] 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.

[0045] Thus, 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 one solenoid valve (i.e. the aforementioned solenoid on-off valve 1021), one three-way valve (i.e. the aforementioned solenoid three-way valve) and one regulating tank (i.e. the aforementioned refrigerant regulating tank 2), so as to realize the redundant regulation of the refrigerant. In the compression refrigeration mode, the idle and non-working fluorine pump 15 is turned on to lift the excess refrigerant through the three-way valve and store it in the regulating tank at a high place, so as to prevent the excessive refrigerant in the refrigeration system from occupying the heat exchange pipe in the heat exchanger (condenser 12 and evaporator 11), and then the solenoid valve is opened to use the gravity migration of the refrigerant liquid in the regulating tank back to the liquid storage tank; in the fluorine pump refrigeration mode, the refrigerant in the regulating tank is migrated back to the liquid storage tank by gravity, so as to ensure that there is enough refrigerant liquid height in the liquid storage tank, so as to prevent the fluorine pump from cavitation due to the excessively low pressure at the suction end of the fluorine pump. The technical solution can accurately and reliably regulate the redundant refrigerant, make full use of the fluorine pump in the standby state and the gravity, and require few additional parts and simple connecting pipes.

[0046] 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:

[0047] Obtaining the operating mode of the fluorine pump compression refrigeration system;

[0048] 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.

[0049] 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 second 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.

[0050] That is, when the system runs in 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, 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 run in the fluorine pump refrigeration mode. In this way, it can be ensured that there is a sufficient refrigerant liquid level in the liquid storage tank 14 to prevent the pressure at the suction end (that is, the liquid inlet) of the fluorine pump 15 from being too low, causing fluorine pump cavitation.

[0051] 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 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 fluorine pump 15 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.

[0052] 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.

[0053] 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 there is too much refrigerant circulating in the system. At this time, the electromagnetic on-off valve 1021 is controlled to be cut off, the flow path switching valve 3 is controlled to be in the first state, and the fluorine pump 15 is controlled to start running until the real-time liquid level rises to the target liquid level h, and then the fluorine pump 15 is controlled to stop running. That is, during the system operation in the compression refrigeration mode, the idle fluorine pump 15 is used to operate to migrate and store excess liquid refrigerant in the system in the refrigerant regulating tank 2, so as to prevent the excessive amount of refrigerant circulating in the system from causing liquid accumulation, thereby improving the heat exchange efficiency; or,

[0054] 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 path switching valve 3 is controlled to be in the second state, and the fluorine pump 15 is controlled to be in a stopped state. At this time, the liquid refrigerant in the refrigerant regulating tank 2 migrates into the liquid storage tank 14 under the action of its own weight to participate in the system circulation, increasing the refrigerant filling amount of the system, until the real-time liquid level drops to the target liquid level h, and the electromagnetic on-off valve 1021 is controlled to be cut off.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] The following combination Figure 1 The technical solution of the present invention is further described:

[0059] 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) → liquid storage tank (i.e. the aforementioned liquid storage tank 14, hereinafter the same) → first one-way valve 1031 → throttle valve (i.e. the aforementioned throttling element 13, hereinafter the same) → evaporator (i.e. the aforementioned evaporator 11, hereinafter the same) → compressor.

[0060] 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: close the solenoid valve (that is, the aforementioned solenoid on-off valve 1021, the same below) and power on to open the ON channel (that is, the aforementioned first state, the same below) / close the OM channel (that is, the aforementioned second state, the same below) of the three-way valve (that is, the aforementioned flow path switching valve 3, the same below), and then turn on the fluorine pump. The fluorine pump lifts the high-pressure refrigerant liquid part of the liquid storage tank outlet to the regulating tank at the top. When the liquid level in the regulating tank reaches height h (that is, the aforementioned When the target liquid level height h is reached, the three-way valve is powered off to close the ON channel / open the OM channel to complete the refrigerant regulation control and close the fluorine pump; 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, and the refrigerant liquid in the regulating tank flows into the gas area at the top of the storage tank through the solenoid valve under the action of gravity and mixes with the refrigerant liquid in the storage tank. When the liquid level height h in the regulating tank drops to the corresponding high frequency of the compressor, the solenoid valve is closed to complete the migration control of the refrigerant.

[0061] 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 → three-way valve OM → throttle valve → evaporator → second one-way valve 1041 → condenser → liquid storage tank → fluorine pump.

[0062] 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 in 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 opened and the ON channel of the three-way valve is closed (that is, the three-way valve is powered on). The refrigerant liquid in the regulating tank enters the liquid storage tank under the action of gravity. 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 closed 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.

[0063] 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.

[0064] 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), a fluorine pump (15) 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 includes a refrigerant regulating tank (2), the top of the refrigerant regulating tank (2) is connected to the top of the liquid storage tank (14) through a first pipeline (101), 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), and the fluorine pump (15) is capable of pumping the liquid refrigerant in the liquid storage tank (14) into the refrigerant regulating tank (2) for storage.

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 liquid outlet of the fluorine pump (15) is connected to the bottom of the refrigerant regulating tank (2) and a second state in which the liquid outlet of the fluorine pump (15) is connected to the liquid inlet of the throttling element (13). The flow path switching valve (3) can be controlled to switch between the first state and the second state. The liquid inlet of the fluorine pump (15) is connected to the bottom of the liquid storage tank (14), 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). A first one-way valve (1031) is connected in series to the third pipeline (103). 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).

4. The fluorine pump compression refrigeration system according to claim 3, characterized in that: The flow path switching valve (3) is an electromagnetic three-way valve.

5. The fluorine pump compression refrigeration system according to claim 3, 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 second 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.

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 according to the obtained real-time operation frequency. 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 fluorine pump (15) are controlled 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 cut off, the flow path switching valve (3) is controlled to be in the first state, and the fluorine pump (15) is controlled to start operation until the real-time liquid level rises to the target liquid level h, and then the fluorine pump (15) is controlled to stop operation; 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 second state, and the fluorine pump (15) is controlled to be in a stopped state, until the real-time liquid level drops to the target liquid level h, and the electromagnetic on-off valve (1021) is controlled to be cut off.

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).

Images