Fluorine pump compression refrigeration system and control method thereof

Abstract

The application provides a fluorine pump compression refrigeration 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 the outlet of the condenser and the inlet of the evaporator. A liquid storage tank is connected between the condenser and the throttling element. The fluorine pump compression refrigeration system further comprises a refrigerant adjusting tank. The top of the refrigerant adjusting tank is communicated with the top of the liquid storage tank through a first pipeline. The bottom of the refrigerant adjusting tank is controllably communicated with 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 adjusting tank. The application can precisely and reliably adjust the redundant refrigerant. When the system runs in the compression refrigeration mode, the fluorine pump which is not in operation is used to store the redundant liquid refrigerant in the refrigerant adjusting tank, so that the excessive refrigerant in the refrigeration system does not occupy the heat exchange pipeline in the heat exchanger.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of air conditioning, and particularly relates to a fluorine pump compression refrigeration system and a control method thereof. BACKGROUND

[0002] With the large application of 4G and the gradual popularization of 5G, the heat generation of various data processing equipment is getting larger and larger, and the data center has higher and higher requirements for the refrigerating capacity and energy saving of air conditioning equipment.

[0003] The outdoor natural cold source in the transition season and cold winter is used to cool the data center, which can greatly reduce the operation cost of the air conditioning equipment. Commonly, a fluorine pump air conditioner is used, the fluorine pump mode is started in winter, the operation of the compressor is stopped, the fluorine pump is used to drive the refrigerant to realize heat pipe refrigeration operation, and the operation cost of the equipment is greatly reduced. The fluorine pump compression refrigeration system belongs to a composite system, and the fluorine pump heat pipe system and the compression refrigeration system share an evaporator and a condenser, as well as some shared refrigerant pipelines, system components and the like.

[0004] Because the heat load of the data center fluctuates with the user usage and the seasonal time, more and more computer room air conditioners now adopt frequency conversion technology to cope with the heat load fluctuation of the data center and to ensure the constant temperature and humidity demand of the data center. However, the change of the frequency of the compressor of the refrigeration system will cause the change of the optimal refrigerant circulation amount, and generally the higher the frequency, the greater the required refrigerant circulation amount. If the optimal refrigerant filling amount under 100% load is ensured during the design and development of the refrigeration system, the optimal refrigerant filling amount under 75% or 50% load or under other low-frequency operation conditions will be less, and therefore the refrigerant in the unit may be accumulated under the low-frequency working condition, and the accumulation of the refrigerant at the bottom of the heat exchanger is not conducive to heat exchange.

[0005] Meanwhile, considering the liquid height requirement of the suction inlet of the fluorine pump, the required refrigerant filling amount under the fluorine pump mode is generally large, and therefore the fluorine pump compression refrigeration system may form the refrigerant liquid accumulation under the actual operation condition, and it is necessary to consider the migration of the accumulated refrigerant to the liquid storage tank, and the release of the accumulated refrigerant liquid in the liquid storage tank to participate in the system circulation operation as soon as possible under the high-frequency compression refrigeration mode or the fluorine pump refrigeration mode. SUMMARY

[0006] Therefore, the present application 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 the required refrigerant filling amount under different operation conditions of the fluorine pump compression refrigeration system in the prior art.

[0007] In order to solve the above problems, the present application 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, a liquid storage tank is connected between the condenser and the throttling element, the fluorine pump compression refrigeration system further comprises a refrigerant adjusting tank, the top of the refrigerant adjusting tank is communicated with the top of the liquid storage tank through a first pipeline, the bottom of the refrigerant adjusting tank is controllably communicated with the top of the liquid storage tank through a second pipeline, and the fluorine pump can pump the liquid refrigerant in the liquid storage tank into the refrigerant adjusting tank.

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

[0009] In some embodiments, the fluorine pump compression refrigeration system further comprises a flow path switching valve, the flow path switching valve has a first state of communicating the outlet of the fluorine pump with the bottom of the refrigerant adjusting tank and a second state of communicating the outlet of the fluorine pump with the inlet of the throttling element, the flow path switching valve can be controlled to switch between the first state and the second state, the inlet of the fluorine pump is communicated with the bottom of the liquid storage tank, a third pipeline is further connected between the inlet of the fluorine pump and the inlet of the throttling element, and a first one-way valve is connected in series on the third pipeline, the one-way direction of the first one-way valve is from the side of the inlet of the fluorine pump to the side of the inlet 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 further comprises a compressor and a fourth pipeline, the suction port of the compressor is communicated with the outlet of the evaporator, the exhaust port of the compressor is communicated with the inlet of the condenser, the fourth pipeline is connected between the suction port and the exhaust port of the compressor, a second one-way valve is connected in series on the fourth pipeline, and the one-way direction of the second one-way valve is from the side of the suction port of the compressor to the side of the exhaust port of the compressor.

[0012] In some embodiments, a liquid level meter is arranged in the refrigerant adjusting tank to detect the real-time liquid level of the refrigerant in the refrigerant adjusting tank; and / or a temperature sensor is arranged in the refrigerant adjusting tank to detect the real-time temperature of the refrigerant in the refrigerant adjusting tank.

[0013] The present application also provides a control method of the fluorine pump compression refrigeration system, comprising the following steps:

[0014] acquiring an operation mode of the fluorine pump compression refrigeration system;

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

[0016] In some embodiments, when the operation mode is the fluorine pump refrigeration mode, the electromagnetic on-off valve is controlled to be on, the flow path switching valve is controlled to be in the second state, the compressor is controlled to be stopped or kept in the stop state, and the electromagnetic on-off valve is controlled to be off and the fluorine pump is controlled to be operated after the refrigerant in the refrigerant adjusting tank completely flows into the liquid storage tank.

[0017] In some embodiments, when the operation mode is the compression refrigeration mode, the compressor is controlled to be operated and a real-time operation frequency of the compressor is acquired, a target liquid level height h of the refrigerant in the refrigerant adjusting tank corresponding to the real-time operation frequency is acquired according to the acquired real-time operation frequency, and the on-off of the electromagnetic on-off valve, the state switching of the flow path switching valve and the start-stop of the fluorine pump are controlled to adjust the real-time liquid level height of the refrigerant in the refrigerant adjusting tank to the target liquid level height h.

[0018] In some embodiments, when the real-time liquid level height of the refrigerant in the refrigerant adjusting tank is lower than the target liquid level height h, the electromagnetic on-off valve is controlled to be off, the flow path switching valve is controlled to be in the first state, and the fluorine pump is controlled to be operated until the real-time liquid level height rises to the target liquid level height h, and the fluorine pump is controlled to be stopped; or,

[0019] when the real-time liquid level height of the refrigerant in the refrigerant adjusting tank is higher than the target liquid level height h, the electromagnetic on-off valve is controlled to be on, the flow path switching valve is controlled to be in the second state, and the fluorine pump is controlled to be in the stop state until the real-time liquid level height drops to the target liquid level height h, and the electromagnetic on-off valve is controlled to be off.

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

[0021] acquiring a system cycle optimal refrigerant filling amount m1 corresponding to the real-time operation frequency, and calculating a refrigerant amount m2 to be stored in the refrigerant adjusting tank, m2 = m-m1, wherein m is a total refrigerant amount in the system;

[0022] acquiring a real-time temperature t and / or a real-time saturation pressure in the refrigerant adjusting tank, and acquiring a liquid refrigerant density p corresponding to the real-time temperature t and / or the real-time saturation pressure according to a refrigerant parameter pre-stored in a controller.

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

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

[0025] When more refrigerant is needed in the system circulation, the second pipeline is controlled to be communicated, so that the liquid refrigerant in the refrigerant regulating tank enters the liquid storage tank to participate in the system circulation, that is, the refrigerant filling amount of the system circulation is increased, and when less refrigerant is needed in the system circulation, the fluorine pump is controlled to operate, so that part of the liquid refrigerant stored in the liquid storage tank in the system circulation is migrated to the refrigerant regulating tank, effectively preventing the accumulation of liquid in the system caused by excessive refrigerant filling amount in the system, and improving the heat exchange efficiency. The technical scheme of the present application can accurately and reliably regulate the redundant refrigerant. When the system operates in the compression refrigeration mode, the idle fluorine pump is used to migrate and store the excess liquid refrigerant in the refrigerant regulating tank, prevent the excess refrigerant in the refrigeration system from occupying the heat exchange pipeline in the heat exchanger, and the number of parts is small and the connection pipeline is simple. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. The drawings in the following description are only exemplary, and those skilled in the art can also obtain other implementation drawings according to the provided drawings without creative labor.

[0027] Figure 1 It is a principle schematic diagram of the fluorine pump compression refrigeration system of the embodiment of the present application.

[0028] The reference signs are:

[0029] 11, evaporator; 111, inner fan; 12, condenser; 121, outer fan; 13, throttling element; 14, liquid storage tank; 15, fluorine pump; 16, compressor; 2, refrigerant regulating tank; 21, liquid level meter; 3, flow path switching valve; 101, first pipeline; 102, second pipeline; 1021, electromagnetic on-off valve; 103, third pipeline; 1031, first one-way valve; 104, fourth pipeline; 1041, second one-way valve. DETAILED DESCRIPTION

[0030] Clearly, the embodiments described are only a part of all the embodiments of the present application, rather than all the embodiments. The following description of at least one example embodiment is merely illustrative in nature and does not limit the present application or its applications or uses in any way. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of the present application.

[0031] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated orientation or position relationship are generally based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, without the opposite description, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, therefore it cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0032] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper" and the like can be used to describe the spatial position relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawings is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" other devices or structures. Therefore, the example term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90° or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0033] In addition, it should be noted that the use of "first", "second" and the like to define parts is only for the convenience of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated, therefore it cannot be understood as a limitation on the scope of protection of the present application.

[0034] Referring to Figure 1As shown, according to the embodiment of the present application, a fluorine pump compression refrigeration system is provided, which comprises an evaporator 11, a condenser 12, a fluorine pump 15 and a throttling element 13 (for example, 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, a liquid storage tank 14 is connected between the condenser 12 and the throttling element 13, and the fluorine pump compression refrigeration system further comprises a refrigerant regulating tank 2, the top of the refrigerant regulating tank 2 is communicated with the top of the liquid storage tank 14 through a first pipeline 101, and the bottom of the refrigerant regulating tank 2 is controllably communicated with the top of the liquid storage tank 14 through a 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, the top space is filled with gaseous refrigerant, and the top of the liquid storage tank 14 is the top space in the tank, and generally, the top space is filled with gaseous refrigerant. Therefore, the first pipeline 101 realizes the top bypass of the gaseous refrigerant in the top space of the refrigerant regulating tank 2 and the liquid storage tank 14, and the bottom of the refrigerant regulating tank 2 and the bottom space of the liquid storage tank 14 are filled with liquid refrigerant. The fluorine pump 15 can pump the liquid refrigerant in the liquid storage tank 14 into the refrigerant regulating tank 2.

[0035] In the technical solution, when more refrigerant is needed in the system circulation, the second pipeline 102 can be controlled to be communicated, so that the liquid refrigerant in the refrigerant regulating tank 2 enters the liquid storage tank 14 to participate in the system circulation, that is, the refrigerant filling amount of the system circulation is increased. When less refrigerant is needed in the system circulation, 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 circulation is migrated to the refrigerant regulating tank 2, which effectively prevents the accumulation of liquid in the system caused by the excessive refrigerant filling amount of the system, and improves the heat exchange efficiency. The technical solution of the present application can accurately and reliably regulate the redundant refrigerant. When the system operates in the compression refrigeration mode, the idle fluorine pump 15 is used to migrate and store the excess liquid refrigerant in the refrigerant regulating tank 2, so as to prevent the excess refrigerant in the refrigeration system from occupying the heat exchange pipeline in the heat exchanger. The technical solution has fewer components and simple connecting pipelines.

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

[0037] In a specific embodiment, an electromagnetic on-off valve 1021 is connected in series on the second pipeline 102, so that the on-off of the second pipeline 102 can be realized by controlling the power-on and power-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, that is, it is opened when powered on and is closed when powered off.

[0038] In another preferred embodiment, the bottom of the refrigerant regulating tank 2 is higher than the top 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 gravity.

[0039] In this technical solution, the refrigerant regulating tank 2 is arranged at a higher position, and when the electromagnetic on-off valve 1021 in the second pipeline 102 is controlled to be open, the liquid refrigerant in the refrigerant regulating tank 2 will enter the liquid storage tank 14 arranged at a lower position under the action of gravity, thereby realizing the increase of the refrigerant filling amount in the system circulation. 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 of the liquid refrigerant under gravity, and the structure is particularly simple, without the need for the targeted configuration of other pumping structures, further reducing the manufacturing cost.

[0040] In some embodiments, the fluorine pump compression refrigeration system further comprises a flow path switching valve 3, the flow path switching valve 3 has a first state of communicating the liquid outlet of the fluorine pump 15 with the bottom of the refrigerant regulating tank 2 and a second state of communicating 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 communicates with the bottom of the liquid storage tank 14, and the liquid inlet of the fluorine pump 15 and the liquid inlet of the throttling element 13 are further connected by a third pipeline 103, the third pipeline 103 is serially connected with a first one-way valve 1031, 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 operating, the first one-way valve 1031 will be closed under the action of the reverse pressure difference to cut off the flow of refrigerant through the third pipeline 103.

[0041] The third pipeline 103 in parallel with the fluorine pump 15 can realize automatic switching between the compression refrigeration mode and the fluorine pump refrigeration mode of the fluorine pump compression refrigeration system, which is simple in structure and easy to implement. Meanwhile, switching of the flow path switching valve 3 can realize one fluorine pump 15 for two purposes. Specifically, when the flow path switching valve 3 is in the first state, the fluorine pump 15 is controlled to operate, and the fluorine pump 15 can pump part of the liquid refrigerant in the liquid storage tank 14 to the refrigerant adjusting tank 2, thereby reducing the filling amount of the refrigerant in the system and ensuring the heat exchange efficiency. At this time, the system operates in the compression refrigeration mode. At this time, it can be understood that the system does not need to be separately configured with a corresponding pumping structure for the migration of the liquid refrigerant to the refrigerant adjusting tank 2, but utilizes the fluorine pump 15 that is originally idle and not working in the compression refrigeration mode, 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 operates in the fluorine pump refrigeration mode.

[0042] Generally, as long as the valve and the valve assembly that can realize the switching between the first state and the second state can be called the flow path switching valve 3 of the present application, for example, realized by a plurality of two-way valves. As a preferred embodiment, the flow path switching valve 3 is a three-way valve, specifically a two-position three-way electromagnetic valve, which can significantly simplify the system design. For details, see Figure 1 As shown, the two-position three-way electromagnetic valve is connected when OM is closed and ON is connected, and is disconnected when OM is connected and ON is closed. Since the fluorine pump 15 is used to lift the refrigerant liquid to the refrigerant adjusting tank 2, the situation is relatively rare and the required time is relatively short. In the compression refrigeration mode, the fluorine pump is mostly in the closed state. In the fluorine pump refrigeration mode, the refrigerant at the outlet of the fluorine pump needs to pass through the OM channel to enter the throttling valve. Therefore, the preferred three-way valve is to use the OM conduction and the ON closed under the condition of power off, which can reduce the power consumption and prolong the service life of the three-way valve.

[0043] In some embodiments, the fluorine pump compression refrigeration system further comprises a compressor 16 and a fourth pipeline 104. The suction port of the compressor 16 is in communication with the gas outlet of the evaporator 11, the exhaust port of the compressor 16 is in communication with the gas inlet of the condenser 12, the fourth pipeline 104 is connected between the suction port and the exhaust port of the compressor 16, and the fourth pipeline 104 is connected in series with a second one-way valve 1041. The one-way conduction direction of the second one-way valve 1041 is from the suction port side of the compressor 16 to the exhaust port side of the compressor 16. When the compressor 16 operates, the second one-way valve 1041 will be cut off under the action of the reverse pressure difference to block the flow of the refrigerant through the fourth pipeline 104.

[0044] In some embodiments, the refrigerant regulating tank 2 is provided with a liquid level gauge 21 for detecting the real-time liquid level of the refrigerant in the refrigerant regulating tank 2; and / or, the refrigerant regulating tank 2 is provided with a temperature sensor (not shown in the figure) 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, only one electromagnetic valve (i.e., the aforementioned electromagnetic on-off valve 1021), one three-way valve (i.e., the aforementioned electromagnetic three-way valve), and one regulating tank (i.e., the aforementioned refrigerant regulating tank 2) need to be added in the technical solution of the present application, so that the redundant refrigerant can be regulated, the idle fluorine pump 15 is opened in the compression refrigeration mode to store the excess refrigerant in the regulating tank through the three-way valve, so as to prevent the excess refrigerant from occupying the heat exchange pipeline in the heat exchanger (the condenser 12 and the evaporator 11), and then the electromagnetic valve is opened to return the refrigerant liquid in the regulating tank to the liquid storage tank by gravity; in the fluorine pump refrigeration mode, the refrigerant in the regulating tank is returned to the liquid storage tank by gravity, so as to ensure that there is enough refrigerant liquid in the liquid storage tank, and prevent the fluorine pump from being cavitated due to the excessively low suction end pressure. The technical solution accurately and reliably regulates the redundant refrigerant, fully utilizes the standby fluorine pump and gravity, and does not need to add many components, and the connecting pipeline is simple.

[0046] According to the embodiments of the present application, a control method of the fluorine pump compression refrigeration system is also provided, which comprises the following steps:

[0047] obtaining the operation mode of the fluorine pump compression refrigeration system;

[0048] controlling the on-off of the electromagnetic on-off valve 1021, the state switching of the flow path switching valve 3, and the start-stop of the compressor 16 and the fluorine pump 15 according to the operation mode.

[0049] Specifically, 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 be stopped or kept in the stopped state, and the electromagnetic on-off valve 1021 is controlled to be cut off and the fluorine pump 15 is controlled to be operated after the refrigerant in the refrigerant regulating tank 2 completely flows into the liquid storage tank 14.

[0050] That is, when the system runs the fluorine pump refrigeration mode, the electromagnetic on-off valve 1021 is first controlled to be turned on before the fluorine pump 15 is controlled to operate, so that the liquid refrigerant in the refrigerant adjusting tank 2 is all migrated back to the liquid storage tank 14 under the action of gravity, and then the fluorine pump 15 is controlled to operate to run the fluorine pump refrigeration mode, so that there is enough liquid refrigerant height in the liquid storage tank 14, and the suction end (i.e. the liquid inlet) of the fluorine pump 15 is prevented from being under too low pressure to cause cavitation of the fluorine pump.

[0051] In some embodiments, 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 adjusting tank 2 corresponding to the real-time operation frequency is obtained according to the obtained real-time operation frequency. The electromagnetic on-off valve 1021, the state switching of the flow path switching valve 3 and the start-stop of the fluorine pump 15 are controlled to adjust the real-time liquid level height of the refrigerant in the refrigerant adjusting tank 2 to the target liquid level height h.

[0052] In the technical scheme, when the system runs the compression refrigeration mode, the corresponding target liquid level height h is obtained according to the real-time operation frequency of the compressor 16, and the real-time liquid level height of the refrigerant in the refrigerant adjusting tank 2 is adjusted to the corresponding target liquid level height h, so as to ensure that the refrigerant filling amount in the system matches each real-time operation frequency, that is, is at the optimal filling amount, and meets the better system circulation amount requirement.

[0053] Specifically, when the real-time liquid level height of the refrigerant in the refrigerant adjusting tank 2 is lower than the target liquid level height h, it indicates that the refrigerant participating in the circulation in the system is too much. 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 operate until the real-time liquid level height rises to the target liquid level height h, and the fluorine pump 15 is controlled to stop operating. That is, during the operation of the system in the compression refrigeration mode, the fluorine pump 15 which is not working is used to operate to migrate the excessive liquid refrigerant in the system to the refrigerant adjusting tank 2, so as to prevent the excessive refrigerant amount in the system from causing the liquid accumulation phenomenon to occur, and to improve the heat exchange efficiency; or,

[0054] When the real-time liquid level height of the refrigerant in the refrigerant adjusting tank 2 is higher than the target liquid level height h, it indicates that the refrigerant participating in the circulation 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 the stop operating state. At this time, the liquid refrigerant in the refrigerant adjusting tank 2 migrates and flows into the liquid storage tank 14 under the action of gravity to participate in the system circulation, so as to increase the refrigerant filling amount of the system, and until the real-time liquid level height decreases to the target liquid level height h, the electromagnetic on-off valve 1021 is controlled to be cut off.

[0055] Thus, the dynamic adjustment of the refrigerant in the system in the compression refrigeration mode is realized, and the filling amount of the refrigerant in the system can meet the optimal system circulation requirement.

[0056] In some embodiments, the target liquid level height h is obtained by: obtaining the optimal refrigerant filling amount m1 corresponding to the real-time operating frequency (pre-stored in the controller), and calculating the refrigerant amount m2 to be stored in the refrigerant adjusting tank 2, m2 = m-m1, wherein m is the total refrigerant amount in the system; obtaining the real-time temperature t and / or real-time saturation pressure in the refrigerant adjusting tank 2, and obtaining the liquid refrigerant density p corresponding to the real-time temperature t and / or real-time saturation pressure according to the pre-stored refrigerant parameters in the controller; and calculating the target liquid level height h according to the formula h = m2 / (pS), wherein S is the cross-sectional area of the storage space of the refrigerant adjusting tank 2, and each of the physical parameters is in international units. In a specific embodiment, the refrigerant adjusting tank 2 is a cylinder with equal diameters at the top and bottom, i.e., each cross-sectional area S is equal, which can further simplify the obtaining of h.

[0057] In the technical solution, the optimal refrigerant filling amount m1 corresponding to the real-time operating frequency pre-stored in the controller is obtained to deduce the refrigerant amount m2 to be stored in the refrigerant adjusting tank 2, and the corresponding target liquid level height is obtained by calculation of relevant physical parameters, which is simple and reliable.

[0058] The technical solutions of the present application are further described below: Figure 1 The technical solutions of the present application are further described below:

[0059] A) Compression refrigeration mode - the fluorine pump (i.e., the fluorine pump 15 described above, the same below) is closed, and the compressor (i.e., the compressor 16 described above, the same below) is started, because the second one-way valve 1041 cannot be turned on due to the reverse pressure difference between the two ends at this time; the main circulation flow path of the refrigerant is: compressor → condenser (i.e., the condenser 12 described above, the same below) → liquid storage tank (i.e., the liquid storage tank 14 described above, the same below) → first one-way valve 1031 → throttling valve (i.e., the throttling element 13 described above, the same below) → evaporator (i.e., the evaporator 11 described above, the same below) → compressor.

[0060] In the compression refrigeration mode, when the compressor frequency is reduced, the system circulation amount required is reduced, and part of the excess refrigerant needs to be migrated to the adjusting tank: the electromagnetic valve (i.e., the aforementioned electromagnetic on-off valve 1021, hereinafter the same) is closed, and the ON channel (i.e., the aforementioned first state, hereinafter the same) of the three-way valve (i.e., the aforementioned flow path switching valve 3, hereinafter the same) is opened, and the OM channel (i.e., the aforementioned second state, hereinafter the same) is closed, and then the fluorine pump is started, which lifts the high-pressure refrigerant liquid at the outlet of the liquid storage tank to the top of the adjusting tank. When the liquid level in the adjusting tank reaches the height h (i.e., the aforementioned target liquid level height h, hereinafter the same), the three-way valve is powered off to close the ON channel and open the OM channel, the refrigerant adjustment control is completed, and the fluorine pump is turned off. When the compressor frequency is increased, the system circulation amount required is increased, and part of the refrigerant in the adjusting tank needs to be migrated to participate in the system circulation: the electromagnetic valve is opened, and the refrigerant liquid in the adjusting tank flows into the gas area at the top of the liquid storage tank under the action of gravity and mixes with the refrigerant liquid in the liquid storage tank, and when the liquid level height h in the adjusting tank decreases to the corresponding high frequency of the compressor, the electromagnetic valve is closed to complete the migration control of the refrigerant.

[0061] B) Fluorine pump refrigeration mode - the fluorine pump is opened, the compressor is closed, and the three-way valve is powered off to open the OM channel and close the ON channel. Because the first one-way valve 1031 cannot be turned on due to the reverse pressure difference between the two ends at this time, the main circulation path of the refrigerant is: fluorine pump → three-way valve OM → throttling valve → evaporator → second one-way valve 1041 → condenser → liquid storage tank → fluorine pump.

[0062] Because the fluorine pump mode requires the most refrigerant filling amount (as explained in the background art, the main reason is to increase the liquid level height in the liquid storage tank to ensure the safety of the fluorant pump and avoid cavitation of the fluorant pump), the refrigerant liquid in the adjusting tank needs to be migrated to the system to participate in the circulation. At this time, the electromagnetic valve is opened, and the ON channel of the three-way valve (i.e., the three-way valve is powered off) is closed. The refrigerant liquid in the adjusting tank enters the liquid storage tank under the action of gravity. When the liquid level height h in the adjusting tank is 0, the electromagnetic valve is closed to complete the migration control of the refrigerant liquid in the adjusting tank, and then the fluorine pump is started to run the fluorine pump refrigeration mode.

[0063] Those skilled in the art will readily understand that the advantageous technical features of the above-mentioned modes can be freely combined and superimposed without conflict.

[0064] The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A refrigerant pump compression refrigeration system, comprising an evaporator (11), a condenser (12), a refrigerant 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 which is connected to the top of the liquid storage tank (14) through a first pipeline (101), and the bottom of which is connected to the top of the liquid storage tank (14) through a second pipeline (102). The refrigerant pump (15) can pump the liquid refrigerant in the liquid storage tank (14) into the refrigerant regulating tank (2).

2. The fluorine pump compression refrigeration system according to claim 1, characterized in that, An electromagnetic on / off valve (1021) is connected in series on 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 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 that connects the outlet of the refrigerant pump (15) to the bottom of the refrigerant regulating tank (2) and a second state that connects the outlet of the refrigerant pump (15) to the 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 inlet of the refrigerant pump (15) is connected to the bottom of the storage tank (14), and a third pipeline (103) is also connected between the inlet of the refrigerant pump (15) and the inlet of the throttling element (13). A first check valve (1031) is connected in series on the third pipeline (103). The unidirectional conduction direction of the first check valve (1031) is from the inlet side of the refrigerant pump (15) to the 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). The suction port of the compressor (16) is connected to the outlet of the evaporator (11), and the discharge port of the compressor (16) is connected to the inlet of the condenser (12). The fourth pipeline (104) is connected between the suction port and the discharge port of the compressor (16), and a second one-way valve (1041) is connected in series on the fourth pipeline (104). The one-way conduction direction of the second one-way valve (1041) is from the suction port side of the compressor (16) to the discharge port 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 equipped with a level gauge (21) for detecting the real-time liquid level of the refrigerant in the refrigerant regulating tank (2); and / or, the refrigerant regulating tank (2) is equipped 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 described in claim 5, characterized in that, Includes the following steps: Obtain the operating mode of the fluorine pump compression refrigeration system; The operation mode is used to control the opening and closing 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).

8. The control method according to claim 7, characterized in that, When the operating mode is the refrigerant pump refrigeration mode, the solenoid on / off valve (1021) is turned on, the flow path switching valve (3) is turned on to the second state, the compressor (16) is turned off or kept in the shutdown state, and after the refrigerant in the refrigerant regulating tank (2) has completely flowed into the liquid storage tank (14), the solenoid on / off valve (1021) is turned off and the refrigerant pump (15) is turned on.

9. The control method according to claim 7, characterized in that, When the operating mode is compression refrigeration mode, the compressor (16) is controlled to operate and the real-time operating frequency of the compressor (16) is obtained. Based on the obtained real-time operating frequency, the target liquid level height h of the refrigerant in the refrigerant regulating tank (2) corresponding to the real-time operating frequency is obtained. The electromagnetic on / off valve (1021) is controlled to open and close, the state switching of the flow path switching valve (3) is controlled, and the start and stop of the refrigerant 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 cut off, the flow path switching valve (3) is controlled to be in the first state, and the refrigerant pump (15) is controlled to start running until the real-time liquid level rises to the target liquid level h, at which point the refrigerant pump (15) is controlled to stop running; 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 open, the flow path switching valve (3) is controlled to be in the second state, and the fluorine pump (15) is controlled to be in the stop operation state until the real-time liquid level drops to the target liquid level h, the electromagnetic on / off valve (1021) is controlled to shut off.

11. The control method according to claim 9, characterized in that, The target liquid level height h is obtained in the following manner: Obtain the optimal refrigerant charge m1 corresponding to the real-time operating frequency, and calculate 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; The real-time temperature t and / or real-time saturation pressure in the refrigerant regulating tank (2) are obtained, and the liquid refrigerant density ρ corresponding to the real-time temperature t and / or real-time saturation pressure is obtained 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), where S is the cross-sectional area of ​​the storage space of the refrigerant regulating tank (2).

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