A liquid storage tank with adjustable liquid storage capacity, a refrigeration system and a control method

Abstract

The application provides a liquid storage tank capable of adjusting the amount of stored liquid, a refrigeration system and a control method. The liquid storage tank comprises an inner cylinder and an outer cylinder. A pipe is arranged at the bottom of the inner cylinder to guide the fluid in the inner cylinder out. A valve structure is arranged between the inner cylinder and the outer cylinder. In the compression refrigeration mode, the valve structure can guide the fluid in the outer cylinder into the inner cylinder when the frequency of the compressor is increased, and the amount of fluid discharged from the pipe is increased. In the compression refrigeration mode, the valve structure can also guide the fluid in the inner cylinder into the outer cylinder when the frequency of the compressor is decreased, and the amount of fluid discharged from the pipe is decreased. In the fluorine pump refrigeration mode, the valve structure can guide the fluid in the outer cylinder into the inner cylinder, and the liquid level in the inner cylinder is increased. According to the application, the problem of refrigerant redundancy caused by the difference in the required refrigerant filling amount under different operating conditions of the fluorine pump compression refrigeration system can be solved, the problem of storage and release of refrigerant liquid can be solved, and the optimal circulation amount required by the refrigeration system under various operating conditions can be met as much as possible.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of refrigeration technology, in particular to a liquid storage tank capable of adjusting the amount of stored liquid, a refrigeration system and a control method. BACKGROUND

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

[0003] Using the outdoor natural cold source in the transition season and cold winter to cool the data center can greatly reduce the operating 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, and the fluorine pump is used to drive the refrigerant to realize heat pipe refrigeration operation, thereby greatly reducing the operating cost of the equipment.

[0004] 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.

[0005] Since 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% or other low frequency operation conditions is relatively small, and therefore the refrigerant in the unit may accumulate under low frequency operating conditions, and the accumulation of the refrigerant at the bottom of the heat exchanger is not conducive to heat exchange.

[0006] Under the fluorine pump mode, considering the liquid height requirement of the fluorine pump suction inlet, the required refrigerant filling amount under the fluorine pump mode is also relatively large, and therefore the fluorine pump compression refrigeration system may form a refrigerant liquid retention condition under actual operating conditions, and it is necessary to consider migrating the retained refrigerant to the liquid storage tank, and to release the refrigerant liquid retained in the liquid storage tank as soon as possible to participate in the system circulation operation under the high frequency compression refrigeration mode.

[0007] Since the fluorine pump compression refrigeration system in the prior art has the technical problem of refrigerant redundancy caused by the difference in the required refrigerant filling amount under different operating conditions, the present application researches and designs a liquid storage tank capable of adjusting the amount of stored liquid, a refrigeration system and a control method. SUMMARY

[0008] Therefore, the present application aims to overcome the defects of the fluorine pump compression refrigeration system in the prior art, which is caused by the difference in the required refrigerant filling amount under different operating conditions, thereby providing a liquid storage tank capable of adjusting the storage liquid amount, a refrigeration system and a control method.

[0009] To solve the above problems, the present application provides a liquid storage tank capable of adjusting the storage liquid amount, comprising:

[0010] An inner cylinder and an outer cylinder, the inner cylinder is located inside the outer cylinder, the outer cylinder is sleeved on the outer periphery of the inner cylinder, the bottom of the inner cylinder is provided with a pipe to guide the fluid in the inner cylinder out, a valve structure is arranged between the inner cylinder and the outer cylinder, in the compression refrigeration mode, the valve structure can guide the fluid in the outer cylinder into the inner cylinder when the frequency of the compressor is increased, so that the amount of fluid discharged from the pipe is increased; in the compression refrigeration mode, the valve structure can also guide the fluid in the inner cylinder into the outer cylinder when the frequency of the compressor is decreased, so that the amount of fluid discharged from the pipe is reduced; in the fluorine pump refrigeration mode, the valve structure can guide the fluid in the outer cylinder into the inner cylinder, so that the liquid level in the inner cylinder is increased.

[0011] In some embodiments,

[0012] The top of the outer cylinder is provided with a pressure tapping port, and a pressure tapping pipe is inserted into the pressure tapping port to communicate the inside of the outer cylinder with an external pressure source; in the compression refrigeration mode and when the frequency of the compressor is increased, the pressure tapping pipe can introduce gas into the inside of the outer cylinder which is greater than the pressure in the inside of the inner cylinder; in the compression refrigeration mode and when the frequency of the compressor is decreased, the pressure tapping pipe can suck the gas in the inside of the outer cylinder and make the pressure in the inside of the outer cylinder less than the pressure in the inside of the inner cylinder; in the fluorine pump refrigeration mode, the pressure tapping pipe can introduce gas into the inside of the outer cylinder which is greater than the pressure in the inside of the inner cylinder.

[0013] In some embodiments,

[0014] Further comprising an inlet pipe, the inlet pipe is inserted into the inner cylinder from above the inner cylinder to introduce fluid into the inner cylinder;

[0015] The inside of the outer cylinder is further provided with a liquid level gauge to detect the liquid level height in the inside of the outer cylinder.

[0016] In some embodiments,

[0017] The valve structure comprises a first one-way valve and a second one-way valve, the first one-way valve is arranged on the cylinder wall of the inner cylinder to only allow the fluid in the outer cylinder to enter the inner cylinder through the first one-way valve; the second one-way valve is arranged on the cylinder wall of the inner cylinder to only allow the fluid in the inner cylinder to enter the outer cylinder through the second one-way valve.

[0018] In some embodiments,

[0019] The first and second one-way valves are the same valve structure, each comprising a valve body, a large passage and a small passage, the valve body is arranged on the cylinder wall of the inner cylinder, the large passage and the small passage are both arranged inside the valve body, the flow cross-sectional area of the large passage is larger than that of the small passage, so that the fluid can only flow from the small passage to the large passage; the small passage of the first one-way valve is arranged in communication with the cavity of the outer cylinder, and the large passage is arranged in communication with the cavity of the inner cylinder; the small passage of the second one-way valve is arranged in communication with the cavity of the inner cylinder, and the large passage is arranged in communication with the cavity of the outer cylinder.

[0020] In some embodiments,

[0021] The valve structure further comprises a valve core and an elastic structure, one end of the small passage is located at one axial end of the valve body, the other end of the small passage extends towards the inside of the valve body, one end of the large passage is in communication with the other end of the small passage, the other end of the large passage is in communication with the other axial end of the valve body, the valve core and the elastic structure are arranged in the large passage, the valve core is relatively close to the small passage, the elastic structure is relatively far away from the small passage, one end of the elastic structure is connected with the valve core, and the other end of the elastic structure is fixed and can exert an elastic pushing force on the valve core, when the pressure in the small passage is greater than the pressure in the large passage plus the elastic pushing force, the valve core is pushed to move away from the small passage, so that the small passage and the large passage are in communication, when the pressure in the large passage plus the elastic pushing force is greater than the pressure in the small passage, the valve core is pushed to block the connection between the small passage and the large passage, so that the small passage and the large passage are not in communication.

[0022] In some embodiments,

[0023] The position where the large passage connects with the small passage is arranged as a transition passage with a trapezoidal longitudinal cross section, the valve core comprises a first valve rod and a second valve rod, the first valve rod can be inserted into the small passage and reciprocate in the small passage, one end of the first valve rod is connected with one end of the second valve rod, the cross-sectional area of the second valve rod is larger than that of the first valve rod, the second valve rod is arranged in the large passage and can also reciprocate in the large passage, and the position where the second valve rod connects with the first valve rod is arranged as a transition structure with a trapezoidal longitudinal cross section, which cooperates with the transition passage;

[0024] The limiting structure is arranged in a part segment of the large channel far from the small channel, one end of the limiting structure abuts or is fixedly connected with one end of the elastic structure, the other end of the limiting structure can extend to the other end face of the valve body, and the inside of the limiting structure has a hollow flow channel to form a channel for fluid flow.

[0025] In some embodiments,

[0026] The first one-way valve and the second one-way valve are both cylindrical structures, the central axes of which are arranged in a horizontal direction, and the inner cylinder and the outer cylinder are also both cylindrical structures, the central axes of which are arranged in a vertical direction.

[0027] The application also provides a refrigeration system comprising the aforementioned liquid storage tank, and further comprising a compressor, a condenser, a throttling valve, an evaporator and a fluorine pump, the throttling valve being arranged between the condenser and the evaporator, the liquid storage tank being arranged between the condenser and the throttling valve, the outlet end of the compressor being communicated with the condenser, the inlet end of the compressor being communicated with the evaporator, and the fluorine pump being arranged in parallel on the pipeline between the throttling valve and the liquid storage tank.

[0028] In some embodiments,

[0029] The first bypass pipeline, the second bypass pipeline and the third bypass pipeline are further included, one end of the first bypass pipeline is communicated with the pressure-taking pipe, the other end of the first bypass pipeline can be communicated to the outlet end of the compressor through the second bypass pipeline or to the inlet end of the condenser, and the other end of the first bypass pipeline can also be communicated to the inlet end of the compressor through the third bypass pipeline or to the outlet end of the evaporator, so that when the frequency of the compressor is increased, the gas with a pressure greater than that in the inner cylinder can be introduced into the outer cylinder through the second bypass pipeline, the first bypass pipeline and the pressure-taking pipe, and when the frequency of the compressor is decreased, the gas in the outer cylinder can be pumped through the third bypass pipeline, the first bypass pipeline and the pressure-taking pipe, and the pressure in the outer cylinder can be reduced to be less than that in the inner cylinder; and in the fluorine pump operation mode, the gas with a pressure greater than that in the inner cylinder can be introduced into the outer cylinder through the third bypass pipeline, the first bypass pipeline and the pressure-taking pipe.

[0030] In some embodiments,

[0031] One end of the second bypass pipeline is communicated to the outlet end of the compressor to introduce the gas at the outlet end of the compressor when the compressor is frequency-boosted, and one end of the third bypass pipeline is communicated to the inlet end of the compressor to introduce at least part of the gas in the outer cylinder to the inlet end of the compressor when the compressor is frequency-reduced; and one end of the third bypass pipeline is communicated to the outlet end of the evaporator to introduce the gas at the outlet end of the evaporator in the fluorine pump operation mode.

[0032] In some embodiments,

[0033] The control valve is further arranged on the first bypass pipeline, and a three-way valve is further arranged at a position where the first bypass pipeline, the second bypass pipeline and the third bypass pipeline meet, and the three-way valve comprises an O end, an N end and an M end, the O end is communicated with the other end of the first bypass pipeline, the N end is communicated with one end of the second bypass pipeline, and the M end is communicated with one end of the third bypass pipeline, and the three-way valve can be switched between a first state and a second state, the first state is that the O end is communicated with the N end and the M end is disconnected, and the second state is that the O end is communicated with the M end and the N end is disconnected.

[0034] The control valve is controlled to be opened when the compressor is frequency-boosted, and the three-way valve is controlled to make the O end communicated with the N end and the M end disconnected at the same time; the control valve is controlled to be opened when the compressor is frequency-reduced, and the three-way valve is controlled to make the O end communicated with the M end and the N end disconnected at the same time; and the control valve is controlled to be opened in the fluorine pump operation mode, and the three-way valve is controlled to make the O end communicated with the M end and the N end disconnected at the same time.

[0035] In some embodiments,

[0036] A first throttling device is further arranged on the second bypass pipeline, and a second throttling device is further arranged on the third bypass pipeline.

[0037] In some embodiments,

[0038] The first throttling device is a capillary tube, and the second throttling device is a capillary tube; the control valve is a solenoid valve, which is opened when powered and closed when powered off; the O end is communicated with the N end and the M end is disconnected when the three-way valve is powered, and the O end is communicated with the M end and the N end is disconnected when the three-way valve is powered off.

[0039] In some embodiments,

[0040] The first branch and the second branch are arranged in parallel at both ends of the compressor, a one-way valve B is arranged on the first branch to allow fluid to flow only from the evaporator to the condenser, and the branch where the fluorine pump is arranged is the second branch, and a one-way valve A is arranged on the pipeline in parallel with the second branch to allow fluid to flow only from the liquid tank to the throttling valve.

[0041] The application also provides a control method of the refrigeration system, which comprises:

[0042] A judgment step is arranged to detect whether the refrigeration system is running in the compression refrigeration mode or the fluorine pump refrigeration mode.

[0043] A detection step is arranged to detect whether the compressor is frequency increasing or frequency decreasing when running in the compression refrigeration mode.

[0044] A control step is arranged to control the control valve to be opened and control the three-way valve to make the O end and the N end communicate and the M end be disconnected when the refrigeration system runs in the compression refrigeration mode and the compressor is frequency increasing, control the control valve to be opened and control the three-way valve to make the O end and the M end communicate and the N end be disconnected when the refrigeration system runs in the compression refrigeration mode and the compressor is frequency decreasing, and control the control valve to be opened and control the three-way valve to make the O end and the M end communicate and the N end be disconnected when the refrigeration system runs in the fluorine pump refrigeration mode.

[0045] In some embodiments,

[0046] When a liquid level gauge is further arranged on the liquid tank,

[0047] The detection step further detects the height of the liquid level inside the outer cylinder through the liquid level gauge.

[0048] The control step controls the control valve to be closed and controls the three-way valve to be powered off to make the O end and the M end communicate and the N end be disconnected when the refrigeration system runs in the compression refrigeration mode, the compressor is frequency increasing, and the above-mentioned control steps of the control valve and the three-way valve are performed, and the liquid level detected by the liquid level gauge drops to a first preset height.

[0049] The control step controls the control valve to be closed and maintains the powered-off state of the three-way valve when the refrigeration system runs in the compression refrigeration mode, the compressor is frequency decreasing, and the above-mentioned control steps of the control valve and the three-way valve are performed, and the liquid level detected by the liquid level gauge rises to a second preset height.

[0050] The control step controls the control valve to be closed and maintains the powered-off state of the three-way valve when the refrigeration system runs in the fluorine pump refrigeration mode and the liquid level detected by the liquid level gauge drops to a third preset height.

[0051] The storage liquid tank, the refrigeration system and the control method provided by the application have the following beneficial effects:

[0052] 1. The application sets the storage liquid tank as a structure of an inner cylinder and an outer cylinder, and sets a valve structure between the inner cylinder and the outer cylinder, so that a specific fluid flow relationship between the inner cylinder and the outer cylinder is achieved, the fluid can be guided out through the outlet pipe at the bottom of the inner cylinder, and the specific fluid flow relationship between the inner cylinder and the outer cylinder is that, in the compression refrigeration mode, the valve structure can guide the fluid in the outer cylinder into the inner cylinder when the frequency of the compressor is increased, so that the amount of fluid discharged from the outlet pipe is increased; in the compression refrigeration mode, the valve structure can also guide the fluid in the inner cylinder into the outer cylinder when the frequency of the compressor is decreased, so that the amount of fluid discharged from the outlet pipe is decreased; and in the fluorine pump refrigeration mode, the valve structure can guide the fluid in the outer cylinder into the inner cylinder, so that the liquid level in the inner cylinder is increased. The unique structure and setting form can increase the flow of fluid discharged from the storage liquid tank when the compression refrigeration mode and the frequency is increased, so that the flow of refrigerant circulating in the system is increased, the heat exchange demand of refrigeration when the high-frequency compressor is operated is met, the normal heat exchange performance is ensured, the fluid in the inner cylinder is guided into the inner cylinder when the frequency of the compressor is decreased, so that the flow of fluid discharged from the storage liquid tank is reduced, the flow of refrigerant circulating in the system is reduced, the heat exchange demand of refrigeration when the low-frequency compressor is operated is met, the situation that too much refrigerant enters the circulation to cause refrigerant retention and affect the heat exchange effect and increase the flow resistance is avoided; and in the fluorine pump mode, the fluid in the outer cylinder is also guided into the inner cylinder, so that the liquid level in the inner cylinder is increased, the liquid suction height of the fluorine pump in the fluorine pump mode is increased, and cavitation is avoided. The application effectively solves the refrigerant redundancy problem caused by the difference in the required refrigerant filling amount of the fluorine pump compression refrigeration system under different operating conditions, solves the problems of refrigerant liquid storage and release, and meets the optimal circulation amount required by the refrigeration system under various operating conditions as much as possible.

[0053] 2. The application also sets the pressure taking port and the pressure taking pipe, so that the inside of the outer cylinder is communicated with the external pressure source under different operating modes and operating conditions, so that the liquid surface height of the inner cylinder is increased when the compressor mode and the frequency are increased, more refrigerant is discharged into the system for circulation, the liquid surface height of the inner cylinder is decreased when the compressor mode and the frequency are decreased, the amount of refrigerant discharged into the system for circulation is reduced, the liquid suction height of the fluorine pump is increased in the fluorine pump mode, and cavitation is avoided, so that the effective and intelligent control purpose is achieved according to the requirements of different conditions, the storage liquid can be accurately controlled, the circulation amount of the refrigeration system is ensured to be in an optimal range, and too much or too little refrigerant participating in the circulation in the refrigeration system is avoided.

[0054] 3. The application can also effectively meet the compressor mode and increase the liquid level of the inner cylinder when the frequency is increased, so that more refrigerant is discharged into the system circulation, and the liquid level of the inner cylinder is reduced when the frequency is decreased, so that the amount of refrigerant discharged into the system circulation is reduced, and the liquid level of the fluorine pump is increased in the fluorine pump mode, so that cavitation is avoided, thereby achieving effective and intelligent control according to the requirements of different working conditions, accurately controlling the storage liquid, and ensuring that the circulation amount of the refrigeration system is in an optimal range, avoiding too much or too little refrigerant participating in the circulation of the refrigeration system. The storage state of the liquid refrigerant in the liquid storage tank can be changed according to the frequency change of the compressor; in the fluorine pump compression refrigeration double-cycle system, the refrigerant gas at the outlet of the evaporator can be used to move the refrigerant liquid in the outer cylinder of the liquid storage tank to the inner cylinder, so that the height of the refrigerant liquid in the inner cylinder of the liquid storage tank meets the requirement of the liquid suction height of the fluorine pump. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1 is the internal sectional view of the liquid storage tank of the application when the outer cylinder is low pressure;

[0056] Figure 2 is the internal sectional view of the liquid storage tank of the application when the outer cylinder is high pressure;

[0057] Figure 3 is the internal sectional view of the one-way valve structure of the application;

[0058] Figure 4 is the system diagram of the fluorine pump compression refrigeration system of the liquid storage tank with adjustable liquid storage amount of the application.

[0059] The reference signs are as follows:

[0060] 1, inner cylinder; 2, outer cylinder; 3, outlet pipe; 4, valve structure; 41, first one-way valve; 42, second one-way valve; 43, valve body; 44, large channel; 45, small channel; 46, valve core; 47, elastic structure; 48, first valve rod; 49, second valve rod; 410, limiting structure; 411, hollow flow channel; 5, pressure taking pipe; 6, liquid level meter; 7, inlet pipe; 8, compressor; 9, condenser; 10, throttling valve; 11, evaporator; 12, fluorine pump; 13, liquid storage tank; 14, one-way valve A; 15, one-way valve B; 16, control valve; 17, three-way valve; O, O end; N, N end; M, M end; 18, first throttling member; 19, second throttling member; 20, inner fan; 21, outer fan;

[0061] 101 first bypass line; 102 second bypass line; 103 third bypass line; 201 first branch; 202 second branch. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and not intended to limit the present application and its applications or uses in any way. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of the present application.

[0063] It should be noted that the terms used herein are only intended to describe specific embodiments and are not intended to limit exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and it should be understood that, when the terms "comprise" and / or "include" are used in the specification, there is a reference to the presence of a feature, step, operation, device, component, and / or combinations thereof.

[0064] Unless specifically stated otherwise, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in the various embodiments described herein are not limiting. It should be understood that the various parts shown in the drawings are not necessarily drawn to scale in proportion. Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the authorized description. In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary, and not as a limitation. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar reference numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0065] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate and imply that the indicated device or element must have a particular orientation or be constructed and operated in a particular 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.

[0066] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0067] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0068] like Figures 1-4 As shown, the present invention provides a liquid storage tank with adjustable liquid storage capacity, comprising:

[0069] The system comprises an inner cylinder 1 and an outer cylinder 2, with the inner cylinder 1 located inside the outer cylinder 2 and the outer cylinder 2 fitted around the outer periphery of the inner cylinder 1. An outlet pipe 3 is provided at the bottom of the inner cylinder 1 to discharge fluid from it. A valve structure 4 is provided between the inner cylinder 1 and the outer cylinder 2. In compression refrigeration mode, the valve structure 4 can guide fluid from the outer cylinder 2 into the inner cylinder 1 when the compressor frequency increases, thereby increasing the amount of fluid discharged from the outlet pipe 3. In compression refrigeration mode, the valve structure 4 can also guide fluid from the inner cylinder 1 into the outer cylinder 2 when the compressor frequency decreases, thereby reducing the amount of fluid discharged from the outlet pipe 3. In refrigerant pump refrigeration mode, the valve structure 4 can guide fluid from the outer cylinder 2 into the inner cylinder 1, thereby raising the liquid level in the inner cylinder 1.

[0070] The application sets the liquid storage tank as a structure of inner and outer sleeve setting, and sets a valve structure between the inner and outer sleeve, can realize the specific fluid flow relationship between the inner and outer sleeve, the out pipe at the bottom of the inner sleeve can guide the fluid out, and the specific fluid flow relationship between the inner and outer sleeve is that: in the compression refrigeration mode, the valve structure can guide the fluid in the outer sleeve into the inner sleeve when the frequency of the compressor is increased, so that the fluid amount discharged from the out pipe is increased; in the compression refrigeration mode, the valve structure can also guide the fluid in the inner sleeve into the outer sleeve when the frequency of the compressor is decreased, so that the fluid amount discharged from the out pipe is decreased; in the fluorine pump refrigeration mode, the valve structure can guide the fluid in the outer sleeve into the inner sleeve, so that the liquid level in the inner sleeve is increased, such a unique structure and setting form can increase the fluid flow discharged from the liquid storage tank when the compression refrigeration mode and the frequency is increased, so that the refrigerant flow circulating in the system is increased, the heat exchange demand of refrigeration when the high-frequency compressor is operated is met, the normal heat exchange performance is ensured, when the frequency of the compressor is decreased, the fluid in the inner sleeve flows into the inner sleeve, so that the fluid flow discharged from the liquid storage tank is decreased, so that the refrigerant flow circulating in the system is decreased, the heat exchange demand of refrigeration when the low-frequency compressor is operated is met, the situation that too much refrigerant enters the circulation to cause the refrigerant to be retained is avoided, the heat exchange effect is affected, and the flow resistance is increased; and in the fluorine pump mode, the fluid in the outer sleeve can also be guided into the inner sleeve, so that the liquid level in the inner sleeve is increased, the liquid suction height of the fluorine pump in the fluorine pump mode is increased, and cavitation is avoided; effectively solve the refrigerant redundancy problem caused by the difference of the required refrigerant filling amount of the fluorine pump compression refrigeration system under different operating conditions, solve the problem of refrigerant liquid storage and release, so as to meet the better circulation amount required by the refrigeration system under various operating conditions as much as possible.

[0071] In some embodiments,

[0072] The top of the outer sleeve 2 is provided with a pressure tapping, and a pressure tapping pipe 5 is inserted at the pressure tapping, so that the inside of the outer sleeve 2 is communicated with the external pressure source; in the compression refrigeration mode and when the frequency of the compressor is increased, the pressure tapping pipe 5 can introduce gas into the inside of the outer sleeve 2 which is greater than the pressure in the inside of the inner sleeve 1; in the compression refrigeration mode and when the frequency of the compressor is decreased, the pressure tapping pipe 5 can suck the gas in the inside of the outer sleeve 2 and make the pressure in the inside of the outer sleeve 2 less than the pressure in the inside of the inner sleeve 1; in the fluorine pump refrigeration mode, the pressure tapping pipe 5 can introduce gas into the inside of the outer sleeve 2 which is greater than the pressure in the inside of the inner sleeve 1.

[0073] The application can also make the inner cylinder communicate with different pressure sources outside the outer cylinder in different operation modes and operation conditions, so that the liquid level of the inner cylinder is raised when the compressor mode and frequency are raised, more refrigerant is discharged into the system to circulate, the liquid level of the inner cylinder is lowered when the compressor mode and frequency are lowered, the amount of refrigerant discharged into the system to circulate is reduced, the liquid suction height of the fluorine pump is raised in the fluorine pump mode, and cavitation is avoided, so that effective and intelligent control is realized according to the requirements of different conditions, the storage liquid can be accurately controlled, the circulating amount of the refrigeration system is ensured to be in an optimal range, and too much or too little refrigerant participating in circulation in the refrigeration system is avoided.

[0074] In some embodiments,

[0075] The inlet pipe 7 is inserted into the inner cylinder 1 from above the inner cylinder 1 to enable fluid to flow into the inner cylinder 1.

[0076] The inner cylinder 2 is also provided with a liquid level meter 6 to detect the liquid level in the inner cylinder 2.

[0077] The application also enables the refrigerant at the outlet end of the condenser to enter the inner cylinder through the inlet pipe, and the liquid level meter arranged in the inner cylinder can effectively detect the liquid level in the inner cylinder, so as to determine whether the liquid level in the outer cylinder is too low during the process of guiding the fluid in the outer cylinder into the inner cylinder, and determine whether the liquid level in the outer cylinder is too high during the process of guiding the fluid in the inner cylinder into the outer cylinder, effectively avoiding these situations and avoiding the situation that the liquid reaches the top.

[0078] The application provides a novel liquid storage tank, preferably a coaxial double-tank structure of an inner tank and an outer tank, and two one-way valves are arranged in the liquid storage tank to communicate the space of the inner tank and the outer tank, a liquid level meter (such as a float liquid level meter or a liquid level sensor) is arranged on the outer tank, the inner tank has an inlet and an outlet, and the top of the outer tank has a pressure tapping. Figure 1 The two one-way valves have different flow directions, one of which only allows fluid to flow from the outer tank to the inner tank (the left one-way valve in the figure), and the other of which only allows fluid to flow from the inner tank to the outer tank (the right one-way valve in the figure). Figure 1

[0079] ​The application applies the above new type of liquid storage tank to the refrigeration system, and can change the liquid refrigerant storage state in the liquid storage tank according to the frequency change of the compressor; in the fluorine pump compression refrigeration double cycle system, the refrigerant gas at the outlet of the evaporator can be used to move the refrigerant liquid of the outer cylinder of the liquid storage tank into the inner cylinder in the fluorine pump mode, so that the height of the refrigerant liquid in the inner cylinder of the liquid storage tank meets the liquid suction height requirement of the fluorine pump.

[0080] In some embodiments,

[0081] The valve structure 4 comprises a first one-way valve 41 and a second one-way valve 42, the first one-way valve 41 is arranged on the cylinder wall of the inner cylinder 1 to only allow the fluid in the outer cylinder 2 to pass through the first one-way valve 41 to enter the inner cylinder 1; the second one-way valve 42 is arranged on the cylinder wall of the inner cylinder 1 to only allow the fluid in the inner cylinder 1 to pass through the second one-way valve 42 to enter the outer cylinder 2.

[0082] This is the preferred structure of the valve structure of the application, that is, by arranging two one-way valves, the first one-way valve only allows the fluid in the outer cylinder to flow into the inner cylinder, and the second one-way valve only allows the fluid in the inner cylinder to flow into the outer cylinder, so that in the compressor frequency increasing or fluorine pump mode, the higher pressure gas is introduced into the outer cylinder through the pressure tapping pipe to drive the fluid in the outer cylinder to flow into the inner cylinder through the first one-way valve, increase the liquid level height of the inner cylinder or discharge more amount of refrigerant into the system to circulate, and when the compressor frequency decreases, at least part of the gas in the outer cylinder is introduced out through the pressure tapping pipe to reduce the pressure in the outer cylinder, drive the fluid in the inner cylinder to flow into the outer cylinder through the second one-way valve, and discharge less amount of refrigerant into the system to circulate, so as to avoid the refrigerant from being stranded in the heat exchanger and other situations, improve the heat exchange performance, and solve the problem of refrigerant redundancy.

[0083] In some embodiments,

[0084] The first one-way valve 41 and the second one-way valve 42 are the same valve structure, both comprising a valve body 43, a large channel 44 and a small channel 45, the valve body 43 is arranged on the cylinder wall of the inner cylinder 1, the large channel 44 and the small channel 45 are both arranged in the inside of the valve body 43, the flow cross-sectional area of the large channel 44 is larger than that of the small channel 45, so that the fluid can only flow from the small channel 45 to the large channel 44; the first one-way valve 41 is arranged such that its small channel 45 communicates with the cavity of the outer cylinder 2, and its large channel 44 communicates with the cavity of the inner cylinder 1; the second one-way valve 42 is arranged such that its small channel 45 communicates with the cavity of the inner cylinder 1, and its large channel 44 communicates with the cavity of the outer cylinder 2.

[0085] This is a specific structure form of the two one-way valves of the present application, the two one-way valves are of the same structure, both including the structure of large and small channels, realizing the function and effect of allowing flow only from the small channel to the large channel, the small channel end of the one-way valve is generally defined as the inlet, the large channel end is defined as the outlet, the flow direction of the one-way valve is from top to bottom along the direction of Figure 3 In the specific embodiments of the present application, the one-way valve is preferably arranged horizontally, that is, the flow direction is horizontal from left to right or from right to left.

[0086] In some embodiments,

[0087] The valve structure further includes a valve core 46 and an elastic structure 47, one end of the small channel 45 is located at one axial end of the valve body 43, the other end of the small channel 45 extends towards the inside of the valve body 43, one end of the large channel 44 communicates with the other end of the small channel 45, the other end of the large channel 44 communicates to the other axial end of the valve body 43, the valve core 46 and the elastic structure 47 are arranged in the large channel 44, the valve core 46 is relatively close to the small channel 45, the elastic structure 47 is relatively far away from the small channel 45, one end of the elastic structure 47 is connected with the valve core 46, the other end of the elastic structure 47 is fixed, and the elastic structure 47 can exert an elastic pushing force on the valve core 46, when the pressure in the small channel 45 is greater than the pressure in the large channel 44 plus the elastic pushing force, the valve core 46 is pushed to move away from the small channel 45, so that the small channel 45 and the large channel 44 are communicated, when the pressure in the large channel 44 plus the elastic pushing force is greater than the pressure in the small channel 45, the valve core 46 is pushed to block the connection between the small channel 45 and the large channel 44, so that the small channel 45 and the large channel 44 are not communicated.

[0088] This is a further preferred structure form of the valve structure of the present application, the valve core can move according to the pressure at both ends, so as to open or close the communication between the small channel and the large channel, and the elastic structure provides a restoring force for the valve core to return to the position combined with the position of the small and large channels, so as to close the communication of the channels.

[0089] When the fluid pressure P1 in the small channel is greater than the fluid pressure P2 in the large channel plus the spring force F (ignoring the gravity and friction of the valve core, etc., such as when the one-way valve is placed horizontally, the gravity can be ignored), the one-way valve is opened, the tapered end of the valve core is pushed away from the tapered transition section, and the fluid flows through the tapered gap; the length of the hollow outer bolt rotating into the large channel is different, that is, the initial compression amount of the spring is different, so as to realize different spring forces, and the greater the spring force, the greater the pressure difference P1-P2 of the fluid opening the one-way valve.

[0090] In some embodiments,

[0091] The position where the large channel 44 meets the small channel 45 is provided with a transition channel with a trapezoidal longitudinal section, the valve core 46 comprises a first valve rod 48 and a second valve rod 49, the first valve rod 48 can be inserted into the small channel 45 and reciprocate in the small channel 45, one end of the first valve rod 48 is connected with one end of the second valve rod 49, the cross-sectional area of the second valve rod 49 is larger than that of the first valve rod 48, the second valve rod 49 is arranged in the large channel 44 and can also reciprocate in the large channel 44, and the position where the second valve rod 49 meets the first valve rod 48 is provided with a transition structure with a trapezoidal longitudinal section, which cooperates with the transition channel;

[0092] The position where the large channel 44 meets the small channel 45 is provided with a transition channel with a trapezoidal longitudinal section, the valve core 46 comprises a first valve rod 48 and a second valve rod 49, the first valve rod 48 can be inserted into the small channel 45 and reciprocate in the small channel 45, one end of the first valve rod 48 is connected with one end of the second valve rod 49, the cross-sectional area of the second valve rod 49 is larger than that of the first valve rod 48, the second valve rod 49 is arranged in the large channel 44 and can also reciprocate in the large channel 44, and the position where the second valve rod 49 meets the first valve rod 48 is provided with a transition structure with a trapezoidal longitudinal section, which cooperates with the transition channel;

[0093] This is a further preferred structure of the valve structure of the present application, that is, the preferred valve core comprises first and second parts with different cross-sectional areas, which cooperate with the small channel and the large channel respectively, and the cooperating structure of the trapezoidal structure can facilitate the guiding of the valve core and is more conducive to the closing of the channel, and the arrangement of the limiting structure can provide support for the elastic structure, which is preferably screwed to the inner wall of the large channel, facilitating the installation and removal of the valve core and the elastic structure and other internal structures.

[0094] As shown in Figure 3 The one-way valve of the present application is composed of a valve body 43, a valve core 46, a spring (elastic structure 47) and a hollow outer bolt (limiting structure 410), the valve body has a small channel 45 and a large channel 44 inside, the small channel 45 and the large channel 44 have a tapered transition section, and the inner wall surface of the large channel of the valve body is provided with internal threads;

[0095] The valve core has a tapered end with the same inclination angle, which can realize close cooperation with the tapered transition section, and when the tapered end of the valve core is attached to the tapered transition section, the valve core can completely block the small channel (the diameter of the valve core body is larger than that of the small channel), thereby realizing the closing function of the one-way valve;

[0096] Further, the tapered end of the valve core is also connected with an elongated positioning rod, the diameter of the positioning rod is smaller than that of the small channel, which functions to make the valve core as close as possible to the central axis of the one-way valve and prevent the valve core from being deflected.

[0097] The other end face of the valve core is connected with a spring, and the two are arranged in the large channel of the valve body, and the valve core is arranged between the tapered transition section of the valve body and the spring;

[0098] The hollow outer bolt has an outer thread feature and is used in cooperation with the inner thread of the large channel. The hollow channel of the hollow outer bolt can be a hexagonal cylindrical hole or a square cylindrical hole, or other types of cylindrical holes. One of the functions of the hollow outer bolt is to enable flow, and the other function is to enable the hollow outer bolt to be screwed into the large channel (the outer end face of the hollow outer bolt can be inside the large channel or outside the large channel) with the aid of a tool. After the hollow outer bolt is connected and positioned with the valve body by means of the thread pair, the inner end face of the hollow outer bolt abuts against the spring, and the tapered end face of the valve core is attached to the tapered surface of the tapered transition section, and the spring is in a compressed state, thereby ensuring the strength of the attachment of the tapered end face of the valve core to the tapered surface of the valve body and ensuring the closed state of the one-way valve.

[0099] Alternatively, the hollow outer bolt has a cylindrical through hole inside, and the sum of the length of the hollow outer bolt and the length of the valve core is greater than the length of the large channel, thereby ensuring that the hollow outer bolt has sufficient length so that after the hollow outer bolt is screwed into the valve body, it still has sufficient length and does not enter the valve body, thereby enabling manual or other tool operation of the rotation of the hollow outer bolt.

[0100] In some embodiments,

[0101] The first one-way valve 41 and the second one-way valve 42 are both cylindrical structures, and the central axes thereof are arranged in a horizontal direction. The inner cylinder 1 and the outer cylinder 2 are also both cylindrical structures, and the central axes thereof are arranged in a vertical direction.

[0102] This is the preferred structure of the first and second one-way valves of the present application, both of which are cylindrical structures and are arranged in a horizontal direction, so that the influence of gravity on both ends of the valve core can be almost ignored, making the reaction and control more precise, and the central axis of the liquid storage tank is preferably arranged in a vertical direction.

[0103] As shown in Figure 1 and Figure 2 The adjustable liquid storage tank provided by the present application is composed of a sealed inner cylinder, a sealed outer cylinder, a pressure taking pipe, a liquid inlet pipe and a liquid outlet pipe. The inner cylinder and the outer cylinder are coaxially arranged, and the upper and lower ends of the inner cylinder are respectively abutted on the inner top end of the outer cylinder and the inner bottom surface of the outer cylinder, and the connection is welded and sealed and fixed.

[0104] The liquid inlet pipe and the liquid outlet pipe are arranged on the inner cylinder, and the pressure taking pipe is arranged at the top end of the outer cylinder.

[0105] Two communication holes are arranged on the wall surface of the inner cylinder close to the bottom;

[0106] One of the one-way valves is arranged on each of the communication holes, wherein the flow direction of one of the one-way valves is from the outer cylinder to the inner cylinder (left one-way valve), and the flow direction of the other one-way valve is from the inner cylinder to the outer cylinder (right one-way valve);

[0107] The valve body of the one-way valve is welded and fixed with the communication hole;

[0108] Further, the outer cylinder of the liquid storage tank is further provided with a liquid level meter (including but not limited to a floating ball liquid level meter, a liquid level sensor, etc.);

[0109] Further, the pressure taking pipe and the liquid level meter are respectively located near two ends of the diameter direction of the liquid storage tank, and the distance therebetween is as far as possible, so as to prevent the disturbance of the fluid in and out of the pressure taking pipe to the liquid level in the outer cylinder space from being too large, and to avoid the influence on the measurement of the liquid level meter from being too large;

[0110] Further, the pipe opening of the pressure taking pipe into the outer cylinder is as close as possible to the inner top end of the outer cylinder, so as to prevent the disturbance of the fluid in and out of the pressure taking pipe to the liquid level in the outer cylinder from being too large; the pipe opening of the liquid outlet pipe in the inner cylinder space is as close as possible to the inner bottom surface of the inner cylinder, so as to ensure the normal liquid outflow (if the pipe opening in the liquid outlet pipe is too high, the liquid outflow phenomenon of sucking the gas at the top will easily occur);

[0111] Further, the outer cylinder is composed of an upper cylinder body and a lower cylinder body, and the two are welded and fixed; the inner cylinder body top and / or bottom respectively passes through the top and bottom of the outer cylinder body, and the connection is welded and fixed; such a structure design is conducive to the smooth implementation of the production process.

[0112] The application also provides a refrigeration system comprising the aforementioned liquid storage tank 13, and further comprising a compressor 8, a condenser 9, a throttling valve 10, an evaporator 11 and a fluorine pump 12, the throttling valve 10 is arranged between the condenser 9 and the evaporator 11, the liquid storage tank 13 is arranged between the condenser 9 and the throttling valve 10, the outlet end of the compressor 8 is communicated with the condenser 9, the inlet end of the compressor 8 is communicated with the evaporator 11, and the fluorine pump 12 is arranged in parallel on the pipeline between the throttling valve 10 and the liquid storage tank 13.

[0113] The unique refrigeration system of the application can guide the fluid in the outer cylinder into the inner cylinder when the compressor is frequency-raised in the compression refrigeration mode, so that the amount of fluid discharged from the outlet pipe is increased; the valve structure can also guide the fluid in the inner cylinder into the outer cylinder when the compressor is frequency-reduced in the compression refrigeration mode, so that the amount of fluid discharged from the outlet pipe is reduced; and the valve structure can guide the fluid in the outer cylinder into the inner cylinder in the fluorine pump refrigeration mode, so that the liquid level in the inner cylinder is raised. Such unique structure and arrangement can increase the fluid flow discharged from the liquid storage tank when the compressor is frequency-raised in the compression refrigeration mode, so as to increase the refrigerant flow circulating in the system, meet the heat exchange requirement of refrigeration when the compressor is operated at high frequency, ensure normal heat exchange performance, and make the fluid in the inner cylinder flow into the inner cylinder when the compressor is frequency-reduced, so as to reduce the fluid flow discharged from the liquid storage tank, reduce the refrigerant flow circulating in the system, meet the heat exchange requirement of refrigeration when the compressor is operated at low frequency, avoid excessive refrigerant from entering the circulation to cause refrigerant retention, affect the heat exchange effect, and increase the flow resistance. In the fluorine pump mode, the fluid in the outer cylinder can also be guided into the inner cylinder, so that the liquid level in the inner cylinder is raised, the liquid suction height of the fluorine pump in the fluorine pump mode is increased, and cavitation is avoided. The refrigerant redundancy problem caused by the difference in the required refrigerant filling amount of the fluorine pump compression refrigeration system under different operating conditions is effectively solved, the refrigerant liquid storage and release problem is solved, and the optimal circulation amount required by the refrigeration system under various operating conditions is as far as possible to be met.

[0114] The application designs a novel liquid storage tank, preferably a coaxial double-tank structure of an inner tank and an outer tank, and two one-way valves are arranged in the liquid storage tank to communicate the space of the inner tank and the outer tank. A liquid level meter (such as a floating ball liquid level meter or a liquid level sensor) is arranged on the outer tank. The inner tank has an inlet and an outlet, and the top of the outer tank has a pressure tapping port. The pressure of the pressure tapping port is changed to respectively open the one-way valves and change the liquid flow direction between the outer tank and the inner tank, so as to adjust the liquid storage state in the liquid storage tank.

[0115] The following problems can be solved:

[0116] The refrigerant redundancy problem caused by the difference in the required refrigerant filling amount of the fluorine pump compression refrigeration system under different operating conditions is effectively solved, the refrigerant liquid storage and release problem is solved, and the optimal circulation amount required by the refrigeration system under various operating conditions is as far as possible to be met.

[0117] In some embodiments,

[0118] The first bypass pipeline 101, the second bypass pipeline 102 and the third bypass pipeline 103 are further included, one end of the first bypass pipeline 101 is communicated with the pressure-taking pipe 5, the other end of the first bypass pipeline 101 can be communicated to the outlet end of the compressor 8 or the inlet end of the condenser 9 through the second bypass pipeline 102, and the other end of the first bypass pipeline 101 can also be communicated to the inlet end of the compressor 8 or the outlet end of the evaporator 11 through the third bypass pipeline 103, so that the gas with a pressure greater than that in the inner cylinder 1 can be introduced into the outer cylinder 2 through the second bypass pipeline 102, the first bypass pipeline 101 and the pressure-taking pipe 5 when the frequency of the compressor 8 is increased, and the gas in the outer cylinder 2 can be sucked and the pressure in the outer cylinder 2 can be reduced to be less than that in the inner cylinder 1 through the third bypass pipeline 103, the first bypass pipeline 101 and the pressure-taking pipe 5 when the frequency of the compressor 8 is decreased; and the gas with a pressure greater than that in the inner cylinder 1 can be introduced into the outer cylinder 2 through the third bypass pipeline 103, the first bypass pipeline 101 and the pressure-taking pipe 5 in the fluorine pump operation mode.

[0119] The present application can introduce the gas with different pressures into the pressure-taking pipe of the outer cylinder through the first, second and third bypass pipelines, so that the liquid level of the inner cylinder is increased when the compressor is in the compressor mode and the frequency is increased, more refrigerant is discharged into the system to circulate, the liquid level of the inner cylinder is reduced when the compressor is in the compressor mode and the frequency is decreased, the amount of the refrigerant discharged into the system to circulate is reduced, the liquid suction height of the fluorine pump is increased in the fluorine pump operation mode, and the cavitation is avoided, so that the effective and intelligent control purpose is achieved according to the requirements of different working conditions, the storage liquid can be accurately controlled, and the circulating amount of the refrigeration system is ensured to be in an optimal range, and the refrigerant participating in the circulation in the refrigeration system is avoided to be too much or too little.

[0120] In some embodiments,

[0121] When the frequency of the compressor 8 is increased, one end of the second bypass pipeline 102 is communicated to the outlet end of the compressor 8, so that the gas at the outlet end of the compressor 8 is introduced, when the frequency of the compressor 8 is decreased, one end of the third bypass pipeline 103 is communicated to the inlet end of the compressor 8, so that at least part of the gas in the outer cylinder 2 is introduced to the inlet end of the compressor 8, and in the fluorine pump operation mode, one end of the third bypass pipeline 103 is communicated to the outlet end of the evaporator 11, so that the gas at the outlet end of the evaporator 11 is introduced.

[0122] This is the further preferred communication position of the second and third bypass pipelines of the application, that is, when the compressor is frequency-raised, it is communicated to the compressor outlet end, and the high-pressure gas at the compressor outlet end can drive the liquid in the outer cylinder into the inner cylinder, increasing the amount of refrigerant circulating in the system, and when the compressor is frequency-reduced, it is communicated to the compressor inlet end, and the low-pressure suction at the compressor inlet end can suck the gas in the outer cylinder to reduce the pressure in the outer cylinder and drive the liquid in the inner cylinder into the outer cylinder, reducing the amount of refrigerant circulating in the system and reducing redundancy; in the fluorine pump mode, the liquid discharge height in the inner cylinder can be effectively increased to prevent cavitation.

[0123] In some embodiments,

[0124] Further comprising a control valve 16 arranged on the first bypass pipeline 101 and a three-way valve 17 arranged at a position where the first bypass pipeline 101, the second bypass pipeline 102 and the third bypass pipeline 103 are connected, and the three-way valve 17 comprises an O end O, an N end N and an M end M, the O end O is communicated with the other end of the first bypass pipeline 101, the N end N is communicated with one end of the second bypass pipeline 102, and the M end M is communicated with one end of the third bypass pipeline 103, and the three-way valve 17 can be switched between a first state and a second state, the first state is that the O end O is communicated with the N end N and the M end M is disconnected, and the second state is that the O end O is communicated with the M end M and the N end N is disconnected.

[0125] When the compressor 8 is frequency-raised, the control valve 16 is controlled to be opened, and at the same time, the three-way valve 17 is controlled to make the O end O communicated with the N end N and the M end M disconnected; when the compressor 8 is frequency-reduced, the control valve 16 is controlled to be opened, and at the same time, the three-way valve 17 is controlled to make the O end O communicated with the M end M and the N end N disconnected; in the fluorine pump operation mode, the control valve 16 is controlled to be opened, and at the same time, the three-way valve 17 is controlled to make the O end O communicated with the M end M and the N end N disconnected.

[0126] The application can realize effective and intelligent control according to the requirements of different working conditions, can accurately control the storage liquid, and thus can ensure that the circulating amount of the refrigeration system is in an optimal range, and can avoid too much or too little refrigerant participating in the circulation in the refrigeration system.

[0127] The adjustable liquid level storage tank with liquid level control can accurately control the storage liquid, and thus can ensure that the circulating amount of the refrigeration system is in an optimal range, and can avoid too much or too little refrigerant participating in the circulation in the refrigeration system; the liquid level change in the storage tank can be controlled by controlling the on-off of the three-way valve and / or the electromagnetic valve through the liquid level sensor, and the new function does not need to change the original control function of the refrigeration system.

[0128] In some embodiments,

[0129] The first throttling member 18 is further arranged on the second bypass pipeline 102, and the second throttling member 19 is further arranged on the third bypass pipeline 103.

[0130] The first and second throttling members arranged on the second and third bypass pipelines respectively can throttle the gas introduced by the compressor outlet or inlet, prevent too much gas from entering or flowing out of the outer cylinder through the pressure-taking pipe, and thus only a small amount of gas with suitable pressure needs to be introduced or flowed out, so that the liquid flow between the inner cylinder and the outer cylinder can be driven in the case of frequency increase, frequency decrease, etc., and the influence on the system is reduced.

[0131] In some embodiments,

[0132] The first throttling member 18 is a capillary tube, and the second throttling member 19 is a capillary tube; the control valve 16 is an electromagnetic valve, the electromagnetic valve is opened when powered, and the electromagnetic valve is closed when powered off; when the three-way valve 17 is powered, the O end O is in communication with the N end N, and the M end M is disconnected; when the three-way valve 17 is powered off, the O end O is in communication with the M end M, and the N end N is disconnected.

[0133] This is the preferred structure of the first and second throttling devices of the present application, as well as the preferred structure of the control valve and the preferred structure of the three-way valve.

[0134] As shown in Figure 4 The present application provides a refrigeration system with an adjustable liquid storage tank, which is connected in sequence by a compressor, a condenser, a liquid storage tank, a throttling valve, and an evaporator. The outlet of the condenser is connected to the liquid inlet pipe of the liquid storage tank, and the inlet of the throttling valve is connected to the liquid outlet pipe of the liquid storage tank.

[0135] In a preferred embodiment, a low-pressure pressure-taking pipe is connected between the low-pressure suction pipe of the refrigeration system (evaporator outlet to compressor suction port) and the pressure-taking pipe of the liquid storage tank; a capillary tube A (second throttling device 19) is connected in series on the low-pressure pressure-taking pipe (third bypass pipe 103); a high-pressure pressure-taking pipe is connected between the high-pressure discharge pipe of the refrigeration system (compressor discharge port to condenser inlet) and the pressure-taking pipe of the liquid storage tank; a capillary tube B (first throttling device 18) is connected in series on the high-pressure pressure-taking pipe (second bypass pipe 102); the low-pressure pipe between the capillary tube A and the pressure-taking pipe of the liquid storage tank and the high-pressure pipe between the capillary tube B and the pressure-taking pipe of the liquid storage tank are combined to form a pressure-taking pipe, i.e., the capillary tube A and the capillary tube B are connected to the pressure-taking pipe, and the other end of the pressure-taking pipe is connected to the pressure-taking pipe of the liquid storage tank; the capillary tube A, the capillary tube B, and the pressure-taking pipe are connected to a three-way valve, the pressure-taking pipe is connected to the common port O of the three-way valve, and the capillary tube A and the capillary tube B are connected to the other two ports M and N, respectively; generally, when the power is off, the OM of the three-way valve is on / ON is off, and when the power is on, the OM of the three-way valve is off / ON is on; an electromagnetic valve is further connected in series on the pressure-taking pipe between the three-way valve and the pressure-taking pipe of the liquid storage tank, and the electromagnetic valve is preferably a normally closed electromagnetic valve; the refrigeration system further includes a fluorine pump, a one-way valve A, and a one-way valve B, the fluorine pump and the one-way valve A are connected in parallel and then connected in series on the pipe between the liquid outlet pipe of the liquid storage tank and the throttling valve, and the flow direction of the fluorine pump and the one-way valve A is only allowed to flow from the liquid storage tank to the throttling valve; the one-way valve B bypasses the compressor, the inlet and outlet of the one-way valve B are connected to the suction port and the discharge port of the compressor, respectively, and the flow direction of the one-way valve B is only allowed to point from the inlet of the compressor to the outlet of the compressor.

[0136] In some embodiments,

[0137] Also included are a first branch 201 and a second branch 202, the first branch 201 is arranged in parallel at both ends of the compressor 8, a one-way valve B15 is arranged on the first branch 201, only allowing fluid to flow from the evaporator 11 to the condenser 9, the branch where the fluorine pump 12 is located is the second branch 202, a one-way valve A14 is arranged on the pipeline in parallel with the second branch 202, only allowing fluid to flow from the liquid storage tank 13 to the throttling valve 10.

[0138] The present application also prevents the refrigerant at the outlet of the compressor from flowing back to the inlet end of the compressor through the second branch in the compression mode, and prevents the refrigerant at the outlet of the fluorine pump from flowing to the inlet end of the fluorine pump, preventing the system from failing to establish a normal circulation in the fluorine pump mode.

[0139] The present application also provides a control method for the refrigeration system as described above, which comprises:

[0140] A judgment step of detecting whether the refrigeration system is running in a compression refrigeration mode or a fluorine pump refrigeration mode;

[0141] A detection step of detecting whether the compressor is frequency increasing or frequency decreasing when running in the compression refrigeration mode;

[0142] A control step of controlling the control valve 16 to be opened, and controlling the three-way valve 17 to make the O end O communicate with the N end N and the M end M be disconnected when the refrigeration system is running in the compression refrigeration mode and the compressor is frequency increasing; controlling the control valve 16 to be opened, and controlling the three-way valve 17 to make the O end O communicate with the M end M and the N end N be disconnected when the compressor is frequency decreasing; controlling the control valve 16 to be opened, and controlling the three-way valve 17 to make the O end O communicate with the M end M and the N end N be disconnected when the refrigeration system is running in the fluorine pump mode.

[0143] This is a preferred step of the control method of the present application, which can reduce the liquid level in the inner cylinder when the compressor is in the compressor mode and frequency decreasing, and reduce the amount of refrigerant discharged into the system, and increase the suction liquid level of the fluorine pump in the fluorine pump mode to avoid cavitation, so as to achieve effective and intelligent control according to the requirements of different working conditions, and accurately control the storage liquid, so as to ensure that the circulation amount of the refrigeration system is in a better range, and avoid too much or too little refrigerant participating in the circulation in the refrigeration system. The storage state of the liquid refrigerant in the liquid storage tank can be changed according to the frequency change of the compressor; in the fluorine pump compression refrigeration double circulation system, the refrigerant liquid in the outer cylinder of the liquid storage tank can be migrated into the inner cylinder by using the refrigerant gas at the outlet of the evaporator in the fluorine pump mode, so as to adapt the height of the refrigerant liquid in the inner cylinder of the liquid storage tank to the suction liquid level requirement of the fluorine pump.

[0144] In some embodiments,

[0145] When the liquid level meter 6 is further arranged on the liquid storage tank 13:

[0146] The detection step further detects the height of the liquid level inside the outer cylinder 2 through the liquid level meter 6.

[0147] The control step, when the refrigeration system runs in the compression refrigeration mode, and the compressor increases the frequency and executes the control steps of the control valve 16 and the three-way valve 17, if the liquid level detected by the liquid level meter 6 drops to the first preset height, first control the control valve 16 to close, and then control the three-way valve 17 to be powered off, so that the O end O is in communication with the M end M, and the N end N is disconnected.

[0148] When the refrigeration system runs in the compression refrigeration mode, and the compressor decreases the frequency and executes the control steps of the control valve 16 and the three-way valve 17, if the liquid level detected by the liquid level meter 6 rises to the second preset height, control the control valve 16 to close, and maintain the power-off state of the three-way valve 17.

[0149] When the refrigeration system runs in the fluorine pump refrigeration mode, if the liquid level detected by the liquid level meter 6 drops to the third preset height, control the control valve 16 to close, and maintain the power-off state of the three-way valve 17.

[0150] The liquid level height detected by the liquid level meter and the specific control form can avoid the liquid level in the outer cylinder from being too low after the frequency increasing control valve and the three-way valve are actuated, avoid the liquid level in the outer cylinder from being too high after the frequency decreasing control valve and the three-way valve are actuated, and avoid the liquid level in the outer cylinder from being too low after the fluorine pump mode control valve and the three-way valve are actuated.

[0151] Figure 4 The working principle of the fluorine pump compression double-circulation refrigeration system:

[0152] A) Compression refrigeration mode - fluorine pump is closed, and compressor is started, and the one-way valve B cannot be turned on because there is a reverse pressure difference between the two ends; the main circulation flow path of the refrigerant is: compressor → condenser → liquid storage tank → one-way valve A → throttling valve → evaporator → compressor.

[0153] When the compressor is frequency up, the system circulation amount is large, so it is hoped that the refrigerant liquid in the outer cylinder of the liquid storage tank is squeezed into the inner cylinder to participate in the system circulation: the solenoid valve is turned on by power, the three-way valve is turned on by power, and the OM is turned on / ON is turned on, so a small part of high-temperature and high-pressure refrigerant gas passes through the capillary B, the three-way valve ON channel and the solenoid valve into the outer cylinder space of the liquid storage tank, and as the amount of gas in the outer cylinder space increases, the pressure P1 of the refrigerant in the outer cylinder space increases, thereby opening the left one-way valve of the liquid storage tank (the one-way valve from the outer cylinder to the inner cylinder), and at least part of the refrigerant liquid in the outer cylinder flows into the inner cylinder through the opened one-way valve until the liquid level meter detects that the liquid level of the outer cylinder of the liquid storage tank drops to a suitable position, and then the solenoid valve is powered off and the three-way valve is powered off (to avoid the following situation: the three-way valve is powered off first, and the OM is turned on at this time, and the solenoid valve is not powered off, so there is a large pressure difference between the high pressure in the outer cylinder space of the liquid storage tank and the low pressure at the suction port of the compressor, which is easy to cause the liquid level in the outer cylinder space to rise).

[0154] When the compressor is frequency down, the system circulation amount is small, so it is hoped that part of the refrigerant liquid in the inner cylinder of the liquid storage tank is squeezed into the outer cylinder for storage to reduce the circulation amount of the refrigeration system: the solenoid valve is turned on by power, and the three-way valve is kept powered off, so the OM is turned on / ON is turned off, and under the suction action of the low-pressure suction port of the compressor, the refrigerant gas in the upper part of the outer cylinder space enters the compressor through the solenoid valve, the three-way valve OM channel and the capillary A, and as the amount of refrigerant gas in the upper part of the outer cylinder space decreases, the refrigerant pressure P1 of the outer cylinder decreases, thereby opening the right one-way valve of the liquid storage tank (the one-way valve from the inner cylinder to the outer cylinder), and at least part of the refrigerant liquid in the inner cylinder flows into the outer cylinder through the opened one-way valve until the liquid level meter detects that the liquid level of the outer cylinder of the liquid storage tank rises to a suitable position, and then the solenoid valve is powered off. If there is no closing action of the solenoid valve, the three-way valve will have at least one channel connected to the pressure tapping pipe of the liquid storage tank in any state, thereby affecting the pressure change in the outer cylinder space of the liquid storage tank, which is not allowed, so the solenoid valve needs to be added to block this action relationship, thereby ensuring the normal operation of the refrigeration system.

[0155] B) Fluorine pump refrigeration mode - the fluorine pump is opened, the compressor is closed, the fluorine pump outlet is in a high-pressure state and the fluorine pump inlet is in a low-pressure state, so the one-way valve A cannot be turned on due to the reverse pressure difference between the two ends; the main circulation flow path of the refrigerant is: fluorine pump → throttling valve → evaporator → one-way valve B → condenser → liquid storage tank → fluorine pump.

[0156] Because the fluorine pump mode needs the most refrigerant filling amount to participate in the circulation (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 fluorine pump and avoid the cavitation phenomenon of the fluorine pump), so it is necessary to migrate as much refrigerant liquid in the outer cylinder space of the liquid storage tank as possible to the inner cylinder to participate in the circulation of the refrigeration system.

[0157] It is known that the fluid pressure gradually decreases along the direction of fluid flow, so it can be known that the gas pressure at the outlet of the evaporator, i.e. the inlet of the capillary A and the inlet of the one-way valve B, is greater than the refrigerant pressure in the liquid tank (the liquid tank is located at the inlet end of the fluorine pump, which is basically the lowest pressure pipe section of the entire system); At this time, the three-way valve is in a power-off state, and the OM is on / off, and opening the electromagnetic valve can make part of the refrigerant gas from the evaporator enter the outer cylinder space of the liquid tank, so that the left one-way valve inside the liquid tank can be opened, forcing the refrigerant liquid in the outer cylinder space to enter the inner cylinder space. When the liquid level meter detects that the outer cylinder liquid level of the liquid tank is in the lowest state, the electromagnetic valve is closed, and the left one-way valve is closed, thereby preventing the refrigerant liquid in the inner cylinder space from entering the outer cylinder space, ensuring that the outer cylinder space basically does not store refrigerant liquid, and meeting the circulating infusion amount in the fluorine pump refrigeration mode.

[0158] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. 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 description is only the preferred embodiment of the present application, and is not intended to limit the present application. 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 liquid storage tank with adjustable liquid storage capacity, characterized in that: include: The inner cylinder (1) and the outer cylinder (2) are located inside the outer cylinder (2). The outer cylinder (2) is fitted around the outer periphery of the inner cylinder (1). The bottom of the inner cylinder (1) is provided with an outlet pipe (3) to allow fluid in the inner cylinder (1) to be discharged. A valve structure (4) is provided between the inner cylinder (1) and the outer cylinder (2). In the compression refrigeration mode, the valve structure (4) can guide the fluid in the outer cylinder (2) into the inner cylinder (1) when the compressor frequency is increased, so that the amount of fluid discharged from the outlet pipe (3) increases. In the compression refrigeration mode, the valve structure (4) can also guide the fluid in the inner cylinder (1) into the outer cylinder (2) when the compressor frequency is reduced, so that the amount of fluid discharged from the outlet pipe (3) decreases. In the refrigerant pump refrigeration mode, the valve structure (4) can guide the fluid in the outer cylinder (2) into the inner cylinder (1), so that the liquid level in the inner cylinder (1) rises. The valve structure (4) includes a first check valve (41) and a second check valve (42). The first check valve (41) is disposed on the wall of the inner cylinder (1) so that fluid in the outer cylinder (2) can only enter the inner cylinder (1) through the first check valve (41). The second check valve (42) is disposed on the wall of the inner cylinder (1) so that fluid in the inner cylinder (1) can only enter the outer cylinder (2) through the second check valve (42).

2. The liquid storage tank with adjustable liquid storage capacity according to claim 1, characterized in that: The top of the outer cylinder (2) is provided with a pressure tap, and a pressure tapping pipe (5) is inserted into the pressure tap to connect the inside of the outer cylinder (2) with an external pressure gas source; in the compression refrigeration mode and when the compressor frequency is increased, the pressure tapping pipe (5) can introduce gas into the outer cylinder (2) with a pressure greater than that inside the inner cylinder (1); in the compression refrigeration mode and when the compressor frequency is decreased, the pressure tapping pipe (5) can draw gas from the inside of the outer cylinder (2) and make the pressure inside the outer cylinder (2) less than that inside the inner cylinder (1); in the refrigerant pump refrigeration mode, the pressure tapping pipe (5) can introduce gas into the outer cylinder (2) with a pressure greater than that inside the inner cylinder (1).

3. The liquid storage tank with adjustable liquid storage capacity according to claim 2, characterized in that: It also includes an inlet pipe (7), which is inserted into the inner cylinder (1) from above to allow fluid to be introduced into the inner cylinder (1); The outer cylinder (2) is also equipped with a level gauge (6) to detect the liquid level inside the outer cylinder (2).

4. The liquid storage tank with adjustable liquid storage capacity according to claim 1, characterized in that: The first check valve (41) and the second check valve (42) have the same valve structure, both including a valve body (43), a large channel (44) and a small channel (45). The valve body (43) is disposed on the wall of the inner cylinder (1). The large channel (44) and the small channel (45) are both opened inside the valve body (43). The flow cross-sectional area of ​​the large channel (44) is larger than that of the small channel (45), so that the fluid can only flow from the small channel (45) to the large channel (44). The first check valve (41) is configured such that its small channel (45) is connected to the cavity of the outer cylinder (2), and its large channel (44) is connected to the cavity of the inner cylinder (1). The second check valve (42) is configured such that its small channel (45) is connected to the cavity of the inner cylinder (1), and its large channel (44) is connected to the cavity of the outer cylinder (2).

5. The liquid storage tank with adjustable liquid storage capacity according to claim 4, characterized in that: The valve structure further includes a valve core (46) and an elastic structure (47). One end of the small channel (45) is located at one axial end of the valve body (43), and the other end of the small channel (45) extends toward the interior of the valve body (43). One end of the large channel (44) is connected to the other end of the small channel (45), and the other end of the large channel (44) is connected to the other axial end of the valve body (43). The valve core (46) and the elastic structure (47) are disposed in the large channel (44). The valve core (46) is relatively close to the small channel (45), and the elastic structure (47) is relatively far away from the small channel (45). One end of the elastic structure (47) is connected to the valve body (43). The valve core (46) is connected to the other end of the elastic structure (47), which can apply an elastic thrust to the valve core (46). When the pressure in the small channel (45) is greater than the pressure in the large channel (44) plus the elastic thrust, the valve core (46) is pushed to move away from the small channel (45), so that the small channel (45) and the large channel (44) are connected. When the pressure in the large channel (44) plus the elastic thrust is greater than the pressure in the small channel (45), the valve core (46) is pushed to block the connection between the small channel (45) and the large channel (44), so that the small channel (45) and the large channel (44) are not connected.

6. The liquid storage tank with adjustable liquid storage capacity according to claim 5, characterized in that: The position where the large channel (44) connects with the small channel (45) is set as a transition channel with a trapezoidal longitudinal section. The valve core (46) includes a first valve stem (48) and a second valve stem (49). The first valve stem (48) can be inserted into the small channel (45) and reciprocate in the small channel (45). One end of the first valve stem (48) is connected to one end of the second valve stem (49). The cross-sectional area of ​​the second valve stem (49) is larger than that of the first valve stem (48). The second valve stem (49) is set in the large channel (44) and can also reciprocate in the large channel (44). The position where the second valve stem (49) connects with the first valve stem (48) is set as a transition structure with a trapezoidal longitudinal section. The transition structure cooperates with the transition channel. A limiting structure (410) is provided in a section of the large channel (44) away from the small channel (45). One end of the limiting structure (410) abuts or is fixed to one end of the elastic structure (47). The other end of the limiting structure (410) can extend to the other end face of the valve body (43). The limiting structure (410) has a hollow flow channel (411) inside to form a channel for fluid flow.

7. The liquid storage tank with adjustable liquid storage capacity according to claim 5, characterized in that: The first check valve (41) and the second check valve (42) are both cylindrical structures with their central axes set in the horizontal direction. The inner cylinder (1) and the outer cylinder (2) are also cylindrical structures with their central axes set in the vertical direction.

8. A refrigeration system, characterized in that: The system includes a liquid storage tank (13) as described in any one of claims 1-7, and further includes a compressor (8), a condenser (9), a throttle valve (10), an evaporator (11), and a refrigerant pump (12). The throttle valve (10) is disposed between the condenser (9) and the evaporator (11). The liquid storage tank (13) is disposed between the condenser (9) and the throttle valve (10). The outlet end of the compressor (8) is connected to the condenser (9), and the inlet end of the compressor (8) is connected to the evaporator (11). The refrigerant pump (12) is disposed in parallel on the pipeline between the throttle valve (10) and the liquid storage tank (13).

9. The refrigeration system according to claim 8, characterized in that: The outer cylinder (2) is provided with a pressure tap at the top, and a pressure tapping pipe (5) is inserted into the pressure tap to connect the interior of the outer cylinder (2) with an external pressure gas source. It also includes a first bypass pipe (101), a second bypass pipe (102) and a third bypass pipe (103). One end of the first bypass pipe (101) is connected to the pressure tapping pipe (5), and the other end of the first bypass pipe (101) can be connected to the outlet end of the compressor (8) or the inlet end of the condenser (9) through the second bypass pipe (102). The other end of the first bypass pipe (101) can also be connected to the inlet end of the compressor (8) or the outlet end of the evaporator (11) through the third bypass pipe (103). When the compressor (8) increases its frequency, it can introduce gas into the outer cylinder (2) through the second bypass pipe (102), the first bypass pipe (101) and the pressure tap (5) at a pressure greater than that inside the inner cylinder (1). When the compressor (8) decreases its frequency, it can also draw gas from the outer cylinder (2) through the third bypass pipe (103), the first bypass pipe (101) and the pressure tap (5) and reduce the pressure inside the outer cylinder (2) to a pressure less than that inside the inner cylinder (1). In the fluorine pump operation mode, it can also introduce gas into the outer cylinder (2) through the third bypass pipe (103), the first bypass pipe (101) and the pressure tap (5) at a pressure greater than that inside the inner cylinder (1).

10. The refrigeration system according to claim 9, characterized in that: When the compressor (8) increases frequency, one end of the second bypass line (102) is connected to the outlet end of the compressor (8) to introduce gas from the outlet end of the compressor (8). When the compressor (8) decreases frequency, one end of the third bypass line (103) is connected to the inlet end of the compressor (8) to draw out at least part of the gas in the outer cylinder (2) to the inlet end of the compressor (8). In the refrigerant pump operation mode, one end of the third bypass line (103) is connected to the outlet end of the evaporator (11) to introduce gas from the outlet end of the evaporator (11).

11. The refrigeration system according to claim 10, characterized in that: It also includes a control valve (16) and a three-way valve (17). The control valve (16) is installed on the first bypass pipeline (101). The three-way valve (17) is installed at the position where the first bypass pipeline (101), the second bypass pipeline (102), and the third bypass pipeline (103) are connected. The three-way valve (17) includes an O end (O), an N end (N), and an M end (M). The O end (O) is connected to the other end of the first bypass pipeline (101), the N end (N) is connected to one end of the second bypass pipeline (102), and the M end (M) is connected to one end of the third bypass pipeline (103). The three-way valve (17) can switch between a first state and a second state. The first state is that the O end (O) is connected to the N end (N) and the M end (M) is disconnected. The second state is that the O end (O) is connected to the M end (M) and the N end (N) is disconnected. When the compressor (8) increases its frequency, the control valve (16) is opened, and the three-way valve (17) is opened to connect the O end (O) and the N end (N), while the M end (M) is disconnected. When the compressor (8) decreases its frequency, the control valve (16) is opened, and the three-way valve (17) is opened to connect the O end (O) and the M end (M), while the N end (N) is disconnected. In the refrigerant pump operation mode, the control valve (16) is opened, and the three-way valve (17) is opened to connect the O end (O) and the M end (M), while the N end (N) is disconnected.

12. The refrigeration system according to claim 11, characterized in that: The second bypass pipe (102) is also provided with a first throttling device (18), and the third bypass pipe (103) is also provided with a second throttling device (19).

13. The refrigeration system according to claim 12, characterized in that: The first throttling element (18) is a capillary tube, and the second throttling element (19) is a capillary tube; the control valve (16) is a solenoid valve, which opens when energized and closes when de-energized; when the three-way valve (17) is energized, the O end (O) is connected to the N end (N) and the M end (M) is disconnected; when the three-way valve (17) is de-energized, the O end (O) is connected to the M end (M) and the N end (N) is disconnected.

14. The refrigeration system according to claim 8, characterized in that: It also includes a first branch (201) and a second branch (202). The first branch (201) is connected in parallel at both ends of the compressor (8). A one-way valve B (15) is provided on the first branch (201) to allow fluid to flow from the evaporator (11) to the condenser (9). The branch where the fluorine pump (12) is located is the second branch (202). A one-way valve A (14) is provided on the pipeline connected in parallel with the second branch (202) to allow fluid to flow from the liquid storage tank (13) to the throttle valve (10).

15. A control method for a refrigeration system as described in any one of claims 11-13, characterized in that: include: The determination step is to check whether the refrigeration system is operating in compression refrigeration mode or refrigerant pump refrigeration mode; The testing procedure involves checking whether the compressor is operating at a higher or lower frequency when running in compression refrigeration mode. The control steps are as follows: when the refrigeration system is running in compression refrigeration mode and the compressor frequency is increased, the control valve (16) is opened, and the three-way valve (17) is controlled to connect the O end (O) and the N end (N), and the M end (M) is disconnected; when the compressor (8) frequency is decreased, the control valve (16) is opened, and the three-way valve (17) is controlled to connect the O end (O) and the M end (M), and the N end (N) is disconnected; when the refrigeration system is running in refrigerant pump operation mode, the control valve (16) is opened, and the three-way valve (17) is controlled to connect the O end (O) and the M end (M), and the N end (N) is disconnected.

16. The control method according to claim 15, characterized in that: When the storage tank (13) is also equipped with a level gauge (6): The detection step also involves detecting the height of the liquid level inside the outer cylinder (2) using the level gauge (6); In the control steps, when the refrigeration system is running in compression refrigeration mode, and the compressor is frequency-increased and executes the control steps of the control valve (16) and the three-way valve (17) as described above, if the liquid level detected by the level gauge (6) drops to the first preset height, the control valve (16) is first controlled to close, and then the three-way valve (17) is controlled to de-energize, so that the O end (O) is connected to the M end (M), and the N end (N) is disconnected; When the refrigeration system is running in compression refrigeration mode, and the compressor reduces its frequency and executes the control steps of the control valve (16) and the three-way valve (17) as described above, if the liquid level detected by the level gauge (6) rises to the second preset height, the control valve (16) is controlled to close, and the three-way valve (17) is kept in a de-energized state. When the refrigeration system is running in the refrigerant pump refrigeration mode, if the liquid level detected by the level gauge (6) drops to the third preset height, the control valve (16) is closed to maintain the power-off state of the three-way valve (17).

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