A fluorine pump compression refrigeration system and a control method thereof

Abstract

The application provides a fluorine pump compression refrigeration system and a control method thereof. The fluorine pump compression refrigeration system comprises a compressor, an oil separator, a condenser, a liquid storage tank, an evaporator, a throttle valve and a fluorine pump. When the compression cycle mode is started, the compressor is started and the fluorine pump is closed. When the fluorine pump refrigeration is started, the fluorine pump is started and the compressor is closed. The fluorine pump compression refrigeration system further comprises a first bypass pipeline and a control valve. One end of the first bypass pipeline is communicated with the inside of the oil separator so as to introduce refrigerant liquid from the oil separator. The other end of the first bypass pipeline is communicated with the inside of the liquid storage tank so as to introduce the refrigerant liquid into the liquid storage tank. The control valve is arranged on the first bypass pipeline. According to the application, the problem of liquid blocking in front of the condenser can be solved, and sufficient refrigerant liquid in the liquid storage tank can be ensured for safe operation of the fluorine pump. The performance of the condenser and the normal operation of the fluorine pump circulation can be ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of refrigeration technology, in particular to a fluorine pump compression refrigeration system and a control method thereof. BACKGROUND

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

[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, and the fluorine pump air conditioner is commonly used, which starts the fluorine pump mode in winter and stops the operation of the compressor to realize heat pipe refrigeration operation by driving the refrigerant with the fluorine pump, 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] In the fluorine pump heat pipe mode of the above composite system, the refrigerant gas at the outlet of the evaporator may carry a large amount of un-evaporated refrigerant liquid, and these refrigerant liquids are prone to accumulate on the gas pipeline before entering the condenser, causing liquid blocking problem, thereby blocking the flow of refrigerant gas in some channels, and thus affecting the gas distribution uniformity and heat exchange efficiency of the condenser. The liquid blocking also affects the flow resistance of the fluorine pump heat pipe circulation, and easily damages the stable operation of the fluorine pump. Therefore, it is necessary to intercept the refrigerant liquid at the outlet of the evaporator and prevent it from returning to the condenser. The more refrigerant liquid is intercepted, the less refrigerant liquid is left in the storage tank, which threatens the operation reliability of the fluorine pump. Therefore, the intercepted refrigerant liquid must be returned to the storage tank as soon as possible.

[0006] The prior application patent 202211620118.5 is provided with a liquid level meter and a linkage controlled electric heater inside the gas-liquid separator, the liquid level inside the gas-liquid separator is detected by the liquid level meter, so as to determine the electric heating power of the electric heater, the accumulated liquid inside the gas-liquid separator is heated and gasified to prevent excessive accumulation of liquid in the gas-liquid separator. The technical solution has the problems of waste of electric energy, direct heating and gasification of un-evaporated refrigerant liquid, waste of refrigeration capacity, and reduction of overall energy efficiency of the system.

[0007] The patent 201320424549.4 adopts a gas-liquid separator and a liquid level controller to solve the liquid accumulation problem, and is applied to a dynamic heat pipe system, and adopts a delay control starting mode. When there is no liquid in the gas-liquid separator, opening the electromagnetic valve will make the gas refrigerant directly return to the suction port of the pump through the liquid return pipeline, which is an unreasonable control mode.

[0008] In the prior art, in the fluorine pump heat pipe mode of the fluorine pump compression refrigeration system, the refrigerant gas at the outlet of the evaporator can carry a large amount of un-evaporated refrigerant liquid, which can easily cause accumulation on the gas pipeline before entering the condenser, thereby causing the problem of liquid blockage, and the like. Therefore, the present application provides a fluorine pump compression refrigeration system and a control method thereof. SUMMARY

[0009] Therefore, the present application aims to overcome the defects in the prior art, i.e., in the fluorine pump heat pipe mode of the fluorine pump compression refrigeration system, the refrigerant gas at the outlet of the evaporator can carry a large amount of un-evaporated refrigerant liquid, which can easily cause accumulation on the gas pipeline before entering the condenser, thereby causing the problem of liquid blockage, and the like. Therefore, the present application provides a fluorine pump compression refrigeration system and a control method thereof.

[0010] To solve the above problems, the present application provides a fluorine pump compression refrigeration system, which comprises:

[0011] a compressor, an oil separator, a condenser, a liquid storage tank, an evaporator, a throttling valve, and a fluorine pump, a compression cycle circuit comprising the compressor, the oil separator, the condenser, the liquid storage tank, the throttling valve, and the evaporator connected to form a loop, a fluorine pump refrigeration circuit comprising the fluorine pump, the evaporator, the oil separator, the condenser, and the liquid storage tank connected to form a loop; when the compression cycle mode is turned on, the compressor is turned on, and the fluorine pump is turned off; when the fluorine pump refrigeration is turned on, the fluorine pump is turned on, and the compressor is turned off.

[0012] Further comprising a first bypass pipeline and a control valve, one end of the first bypass pipeline is connected to the inside of the oil separator to introduce refrigerant liquid from the oil separator, the other end of the first bypass pipeline is connected to the inside of the liquid storage tank to introduce refrigerant liquid into the liquid storage tank, and the control valve is arranged on the first bypass pipeline.

[0013] In some embodiments, the control valve can be opened when the refrigerant liquid in the evaporator is not completely evaporated, so that the first bypass pipeline is connected; and the control valve can be closed when the refrigerant liquid in the evaporator is completely evaporated, so that the first bypass pipeline is not connected.

[0014] In some embodiments, the opening or closing of the control valve is controlled by the difference between the outlet refrigerant temperature and the inlet refrigerant temperature of the evaporator, the control valve is controlled to be opened when the difference between the outlet refrigerant temperature and the inlet refrigerant temperature of the evaporator is less than or equal to a preset value, at this time the refrigerant liquid in the evaporator is not completely evaporated, and the oil separator has refrigerant liquid inside; the control valve is controlled to be closed when the difference between the outlet refrigerant temperature and the inlet refrigerant temperature of the evaporator is greater than the preset value, at this time the refrigerant liquid in the evaporator is completely evaporated.

[0015] In some embodiments, one end of the first bypass pipeline is communicated to the inside bottom of the oil separator, the other end of the first bypass pipeline is communicated from the top of the liquid storage tank to the inside of the liquid storage tank, and the other end of the first bypass pipeline is located above the liquid level in the liquid storage tank.

[0016] In some embodiments, further comprising a gas-liquid separator, a first pipeline, a second pipeline and a third pipeline, one end of the first pipeline is communicated to the outlet of the evaporator, and the other end is communicated to the inside of the gas-liquid separator, one end of the second pipeline is communicated to the inside of the gas-liquid separator, and the other end is communicated to the suction port of the compressor, one end of the third pipeline is communicated to the second pipeline, and the other end is communicated to the first bypass pipeline.

[0017] In some embodiments, the third pipeline is communicated to a position on the first bypass pipeline between the oil separator and the control valve, and a throttling device is arranged on the third pipeline.

[0018] In some embodiments, further comprising a fourth pipeline and a fifth pipeline, one end of the fourth pipeline is communicated to the gas outlet of the compressor, and the other end is communicated to the inside of the oil separator, one end of the fifth pipeline is communicated to the first pipeline, and the other end is communicated to the fourth pipeline, a one-way valve B is arranged on the fifth pipeline, and the one-way valve B only allows fluid to flow from the first pipeline to the fourth pipeline;

[0019] Further comprising a sixth pipeline and a one-way valve A, the sixth pipeline is arranged in parallel at both ends of the fluorine pump, and the one-way valve A only allows fluid to flow from the inlet end of the fluorine pump to the outlet end of the fluorine pump through the sixth pipeline.

[0020] In some embodiments, further comprising a second bypass pipeline, one end of the second bypass pipeline is communicated to the inside of the gas-liquid separator to guide the refrigerant liquid inside the gas-liquid separator out, and the other end of the second bypass pipeline is communicated to the first bypass pipeline.

[0021] In some embodiments, one end of the second bypass line is connected to the bottom of the gas-liquid separator, and the other end of the second bypass line is connected to the first bypass line at a position between the oil separator and the control valve. The second bypass line is also provided with a one-way valve C, which only allows refrigerant fluid to flow from the gas-liquid separator toward the first bypass line.

[0022] In some implementations, the location where the second bypass pipe connects to the first bypass pipe is the same as the location where the third pipe connects to the first bypass pipe.

[0023] The present invention also provides a control method for a fluorine pump compression refrigeration system as described above, comprising:

[0024] The testing steps include detecting the operating mode of the refrigerant pump compression refrigeration system, and detecting the outlet refrigerant temperature and inlet refrigerant temperature of the evaporator.

[0025] The judgment step involves determining whether the operating mode of the refrigerant pump compression refrigeration system is compression refrigeration mode or refrigerant pump refrigeration mode; and when the difference between the refrigerant temperature at the outlet of the evaporator and the refrigerant temperature at the inlet of the evaporator is less than or equal to a preset value, it is determined that the refrigerant liquid in the evaporator has not completely evaporated, and the refrigerant gas at the outlet of the evaporator carries the refrigerant liquid; when the difference between the refrigerant temperature at the outlet of the evaporator and the refrigerant temperature at the inlet of the evaporator is greater than the preset value, it is determined that the refrigerant liquid in the evaporator has completely evaporated.

[0026] The control steps are as follows: when the operating mode of the refrigerant pump compression refrigeration system is the refrigerant pump refrigeration mode: and when it is determined that the refrigerant liquid in the evaporator has not completely evaporated, the control valve is opened; and when it is determined that the refrigerant liquid in the evaporator has completely evaporated, the control valve is closed.

[0027] In some embodiments, the control step, when the operating mode is the refrigerant pump refrigeration mode: and when the difference between the outlet refrigerant temperature and the inlet refrigerant temperature of the evaporator is less than or equal to a preset value for a duration t1, controls the control valve to open while maintaining the refrigerant pump refrigeration mode, and maintains the control valve open for a duration t2; then closes the control valve, and re-detects the outlet refrigerant temperature and the inlet refrigerant temperature of the evaporator, and re-accumulates and counts the t1 time.

[0028] In some embodiments, the control step involves closing the control valve when the operating mode of the refrigerant pump compression refrigeration system is compression refrigeration mode.

[0029] The fluorine pump compression refrigeration system and its control method provided by the present invention have the following beneficial effects:

[0030] 1. This invention, by setting up a first bypass pipeline and a control valve, connects the first bypass pipeline between the oil separator and the liquid receiver. This effectively guides the refrigerant liquid back to the liquid receiver when the amount of liquid refrigerant in the oil separator is large. This ensures that the refrigerant liquid separated in the oil separator can directly return to the high-pressure liquid receiver through the bypass pipeline, thus preventing refrigerant liquid from entering the condenser. This effectively avoids the problem of liquid blockage caused by refrigerant accumulation in the gas pipeline before entering the condenser, preventing obstruction of refrigerant gas flow, reducing the impact on the uniformity of gas distribution in the condenser, and improving the heat exchange efficiency of the condenser. Furthermore, it effectively returns the refrigerant liquid to the refrigerant pump circulation loop through the liquid receiver, ensuring sufficient refrigerant liquid remains in the liquid receiver. This effectively ensures the continuous and effective operation of the refrigerant pump heat pipe circulation, improving the reliability of the refrigerant pump operation. Therefore, this invention can solve the problem of liquid blockage before the condenser while ensuring sufficient refrigerant liquid in the liquid receiver for the safe operation of the refrigerant pump, guaranteeing both condenser performance and the normal operation of the refrigerant pump circulation.

[0031] 2. The present invention also effectively connects the interior of the gas-liquid separator and the first bypass pipe through the second bypass pipe, thereby effectively guiding the refrigerant liquid separated in the gas-liquid separator into the liquid receiver tank. This further guides the refrigerant liquid that has not been completely evaporated in the evaporator into the liquid receiver tank, further reducing the amount of refrigerant liquid entering the condenser inlet, further reducing and avoiding liquid blockage at the condenser inlet, and further improving the heat exchange efficiency of the condenser. Furthermore, it increases the amount of refrigerant liquid entering the liquid receiver tank, enhancing the refrigerant circulation volume during refrigerant pump circulation, and further ensuring the normal and safe operation of the refrigerant pump circulation.

[0032] 3. The control method of the present invention preferably uses the temperature difference between the inlet and outlet of the evaporator to determine whether evaporation is complete. If the temperature difference is greater than the preset value, it indicates that evaporation is complete. At this time, there is little or almost no refrigerant liquid in the oil separator and / or gas-liquid separator, which will not cause liquid blockage at the inlet of the condenser. There is sufficient refrigerant in the system circulation loop. Therefore, the control valve is closed at this time, and there is no need to bypass the refrigerant to the liquid receiver through the first bypass pipeline. However, if the above temperature difference is less than or equal to the preset value, it indicates that the refrigerant in the evaporator is not completely evaporated. This will result in a certain or a large amount of refrigerant liquid at the outlet of the evaporator. The refrigerant liquid will enter the oil separator and the gas-liquid separator, causing liquid blockage at the inlet of the condenser and low refrigerant in the liquid receiver. At this time, the control valve needs to be opened so that the refrigerant liquid in the oil separator (more preferably, a gas-liquid separator is added) can smoothly enter the liquid receiver. This preferably reduces the amount of refrigerant liquid entering the condenser, reduces or prevents liquid blockage, and effectively ensures that there is sufficient refrigerant entering the liquid receiver, ensuring the normal and safe operation of the refrigerant pump circulation. Attached Figure Description

[0033] Figure 1 This is a structural diagram of the fluorine pump compression refrigeration system of Embodiment 1 of the present invention;

[0034] Figure 2 This is a structural diagram of the fluorine pump compression refrigeration system of Embodiment 2 of the present invention.

[0035] The attached figures are labeled as follows:

[0036] 1. Compressor; 2. Oil separator; 3. Condenser; 4. Liquid receiver; 5. Evaporator; 6. Throttling valve; 7. Refrigerant pump; 8. Control valve; 9. Gas-liquid separator; 10. Throttling device; 11. Check valve B; 12. Check valve A; 13. Check valve C; 14. External fan; 15. Internal fan; 101. First bypass line; 102. Second bypass line; 201. First line; 202. Second line; 203. Third line; 204. Fourth line; 205. Fifth line; 206. Sixth line. Detailed Implementation

[0037] Example 1, such as Figure 1 As shown, the present invention provides a fluorine pump compression refrigeration system, which includes:

[0038] The system comprises a compressor 1, an oil separator 2, a condenser 3, a liquid receiver 4, an evaporator 5, a throttle valve 6, and a refrigerant pump 7. The compression cycle circuit includes a loop formed by connecting the compressor 1, the oil separator 2, the condenser 3, the liquid receiver 4, the throttle valve 6, and the evaporator 5. The refrigerant pump refrigeration circuit includes a loop formed by connecting the refrigerant pump 7, the evaporator 5, the oil separator 2, the condenser 3, and the liquid receiver 4. When the compression cycle mode is activated, the compressor 1 is on and the refrigerant pump 7 is off. When the refrigerant pump refrigeration mode is activated, the refrigerant pump 7 is on and the compressor 1 is off.

[0039] It also includes a first bypass line 101 and a control valve 8 (preferably a solenoid valve). One end of the first bypass line 101 is connected to the interior of the oil separator 2 so as to introduce refrigerant liquid from the oil separator 2. The other end of the first bypass line 101 is connected to the interior of the liquid storage tank 4 so as to introduce refrigerant liquid into the liquid storage tank. The control valve 8 is disposed on the first bypass line 101.

[0040] This invention, by setting up a first bypass pipeline and a control valve, connects the first bypass pipeline between the oil separator and the liquid receiver. This effectively guides the refrigerant liquid in the oil separator back to the liquid receiver when the amount of liquid refrigerant is large, ensuring that the refrigerant liquid separated in the oil separator can directly return to the high-pressure liquid receiver through the bypass pipeline. This prevents refrigerant liquid from entering the condenser, effectively avoiding the problem of liquid blockage caused by refrigerant accumulation in the gas pipeline before entering the condenser, preventing obstruction of refrigerant gas flow, reducing the impact on the uniformity of gas distribution in the condenser, and improving the heat exchange efficiency of the condenser. Furthermore, it effectively returns the refrigerant liquid to the refrigerant pump circulation loop through the liquid receiver, ensuring sufficient refrigerant liquid remains in the liquid receiver. This effectively ensures the continuous and efficient operation of the refrigerant pump heat pipe circulation, improving the reliability of the refrigerant pump operation. Therefore, this invention solves the problem of liquid blockage before the condenser while ensuring sufficient refrigerant liquid in the liquid receiver for the safe operation of the refrigerant pump, guaranteeing both condenser performance and the normal operation of the refrigerant pump circulation.

[0041] Compared to the prior art, this invention eliminates the need for a device to heat and vaporize the liquid in the gas-liquid separator, effectively avoiding the waste of electrical energy and the waste of the cooling capacity of the unevaporated refrigerant liquid. Furthermore, compared to the method of directly returning gaseous refrigerant to the pump inlet, this invention effectively utilizes liquid refrigerant and circulates it effectively. The prior art cannot reasonably recover and utilize liquid refrigerant, cannot effectively increase the refrigerant in the refrigerant circulation system, and cannot effectively ensure the continuous and effective operation of the refrigerant pump circulation.

[0042] This invention connects a bypass pipe between the oil outlet of the oil separator and the inlet of the high-pressure liquid receiver. A solenoid valve on the pipe controls the opening and closing of the bypass. In the natural cooling refrigerant pump heat pipe mode, the gas-liquid refrigerant at the evaporator outlet undergoes gas-liquid separation within the oil separator. By comparing the refrigerant temperature at the evaporator outlet with the refrigerant temperature at the inlet, the system determines whether the refrigerant at the evaporator outlet has completely evaporated, thus determining the presence of liquid refrigerant in the oil separator. This, in turn, controls the opening and closing of the solenoid valve, ensuring that the liquid refrigerant separated in the oil separator can directly return to the high-pressure liquid receiver through the bypass pipe. This prevents liquid refrigerant from returning from the evaporator to the condenser, ensuring condenser performance and maintaining sufficient liquid refrigerant in the receiver for the safe operation of the refrigerant pump. It effectively separates the refrigerant gas and liquid at the evaporator outlet, preventing liquid refrigerant from entering the condenser, ensuring uniform gas distribution in the condenser, and avoiding liquid blockage.

[0043] In some embodiments, the control valve 8 can be opened when the refrigerant liquid in the evaporator 5 is not completely evaporated, thus connecting the first bypass line 101; the control valve 8 can be closed when the refrigerant liquid in the evaporator 5 is completely evaporated, thus deactivating the first bypass line 101. This is a preferred control form of the control valve of the present invention, that is, the control valve can control whether to open or not according to the degree of evaporation of the refrigerant liquid in the evaporator. If the refrigerant liquid is not completely evaporated, it means that there will be liquid refrigerant entering the oil separator and gas-liquid separator. At this time, in order to avoid liquid refrigerant entering the condenser and causing liquid blockage, the control valve is opened to export the liquid refrigerant in the oil separator to the liquid storage tank through the first bypass line, which not only prevents liquid blockage but also effectively increases the refrigerant charge in the liquid storage tank, ensuring the safe and reliable operation of the refrigerant pump circulation; while if the refrigerant liquid is completely evaporated, the control valve is closed. At this time, it is not necessary to connect, because at this time there is little or no refrigerant liquid, which will not cause liquid blockage or insufficient refrigerant charge in the refrigerant pump circulation.

[0044] In some embodiments, the opening or closing of the control valve 8 can be controlled by the difference between the outlet refrigerant temperature and the inlet refrigerant temperature of the evaporator 5. The control valve 8 can be opened when the difference between the outlet and inlet refrigerant temperatures is less than or equal to a preset value, at which point the refrigerant liquid in the evaporator 5 is not completely evaporated, and refrigerant liquid remains inside the oil separator 2. Conversely, the control valve 8 can be closed when the difference between the outlet and inlet refrigerant temperatures is greater than the preset value, at which point the refrigerant liquid in the evaporator 5 is completely evaporated. This is a further control form of the control valve of the present invention, where whether the liquid refrigerant in the evaporator is completely evaporated is measured and judged by the difference between the outlet and inlet refrigerant temperatures. A larger difference indicates complete evaporation, while a smaller difference indicates incomplete evaporation, thus further controlling whether the control valve is closed or not. This effectively achieves the purpose of closing the control valve when evaporation is complete and opening it when evaporation is incomplete, thereby guiding the refrigerant liquid to the liquid storage tank.

[0045] In this invention, a bypass pipe is connected between the oil outlet of the oil separator and the inlet of the high-pressure liquid storage tank. A solenoid valve is installed on the pipe to control the opening and closing of the bypass pipe. In the natural cooling refrigerant pump heat pipe mode, the gas-liquid refrigerant at the evaporator outlet is separated into gas and liquid in the oil separator. By judging the temperature of the refrigerant at the evaporator outlet and the temperature of the refrigerant at the inlet, it is determined whether the refrigerant at the evaporator outlet has evaporated completely, thereby determining whether there is refrigerant liquid in the oil separator, and then controlling the opening and closing of the solenoid valve to ensure that the refrigerant liquid separated in the oil separator can return directly to the high-pressure liquid storage tank through the bypass pipe.

[0046] In some embodiments, one end of the first bypass pipe 101 is connected to the bottom of the oil separator 2, and the other end of the first bypass pipe 101 is connected from the top of the liquid storage tank 4 to the interior of the liquid storage tank 4. The other end of the first bypass pipe 101 is also located above the liquid level inside the liquid storage tank 4. This is a further preferred structural form of the first bypass pipe of the present invention, that is, its connection point with the oil separator is located at the bottom of the oil separator, which can effectively introduce liquid refrigerant from the bottom of the oil separator and then export it to the liquid storage tank; the other end of the first bypass pipe is connected from the top of the liquid storage tank to its interior, which can effectively prevent the liquid in the liquid storage tank from flowing back into the first bypass pipe due to its location at the bottom of the liquid storage tank, and also prevent the refrigerant in the first bypass pipe from not being able to enter the liquid storage tank, effectively utilizing the gravity of the refrigerant liquid to allow it to smoothly enter the liquid storage tank.

[0047] In some embodiments, the system further includes a gas-liquid separator 9, a first pipeline 201, a second pipeline 202, and a third pipeline 203. One end of the first pipeline 201 is connected to the outlet of the evaporator 5, and the other end is connected to the interior of the gas-liquid separator 9. One end of the second pipeline 202 is connected to the interior of the gas-liquid separator 9, and the other end is connected to the suction port of the compressor 1. One end of the third pipeline 203 is connected to the second pipeline 202, and the other end is connected to the first bypass pipeline 101. This is a further preferred structural form of the present invention. By setting up the gas-liquid separator, the refrigerant entering the compressor can be separated into gas and liquid phases. Furthermore, the third pipeline can effectively guide the liquid refrigerant and oil separated in the oil separator into the gas-liquid separator, providing sufficient lubricating oil for the compressor operation.

[0048] The outlet of the evaporator and the inlet of the one-way valve B of the present invention are preferably connected together to the inlet of the gas-liquid separator, and the outlet of the gas-liquid separator and the outlet of the capillary tube are preferably connected together to the suction port of the compressor.

[0049] In some embodiments, the third pipeline 203 is connected to the first bypass pipeline 101 at a position between the oil separator 2 and the control valve 8; a throttling device 10 is provided on the third pipeline 203. The third pipeline of the present invention is used to ensure effective oil return to the compressor, and the capillary tube effectively reduces pressure, ensuring that the refrigerant entering the gas-liquid separator is at low pressure. The throttling device 10 is preferably a capillary tube.

[0050] In some embodiments, a fourth pipeline 204 and a fifth pipeline 205 are also included. One end of the fourth pipeline 204 is connected to the outlet of the compressor 1 and the other end is connected to the interior of the oil separator 2. One end of the fifth pipeline 205 is connected to the first pipeline 201 and the other end is connected to the fourth pipeline 204. A one-way valve B11 is provided on the fifth pipeline 205. The one-way valve B11 can only allow fluid to flow from the first pipeline 201 to the fourth pipeline 204.

[0051] It also includes a sixth pipeline 206 and a one-way valve A12. The sixth pipeline 206 is arranged in parallel at both ends of the fluorine pump 7. The one-way valve A12 can only allow fluid to flow from the inlet end of the fluorine pump 7 through the sixth pipeline 206 to the outlet end of the fluorine pump 7.

[0052] This is a further preferred structural form of the present invention. The compressor can be effectively bypassed in parallel through the fifth pipeline. It is suitable for use in the refrigerant pump refrigeration mode. In the refrigerant pump refrigeration mode, the compressor is turned off, and the refrigerant flowing out of the evaporator flows to the oil separator through the fifth pipeline. The purpose of the sixth pipeline and the one-way valve A of the present invention is that in the compression refrigeration mode, the refrigerant pump is turned off, and at this time the refrigerant flows to the throttle valve through the one-way valve A.

[0053] The main reason why the inlet of the one-way valve B in this invention cannot be connected to the outlet of the gas-liquid separator along with the compressor's suction port is that if liquid accumulates inside the gas-liquid separator, and the liquid level overflows the oil return hole at the bottom of the U-shaped tube inside the outlet pipe, refrigerant liquid and / or lubricating oil will enter the U-shaped tube and form a liquid blockage. In refrigerant pump mode, the refrigerant gas passing through the U-shaped tube will encounter this liquid blockage resistance, which creates the problems or defects of the prior art described in the background section. Therefore, this invention, through the first, second, third, fourth, and fifth pipelines and their corresponding connections, ensures that the inlet of the one-way valve B is not connected to the outlet of the gas-liquid separator along with the compressor's suction port, thereby preventing severe liquid blockage in the gas-liquid separator in refrigerant pump mode and further reducing the liquid blockage at the condenser inlet.

[0054] like Figure 1 As shown, the refrigerant pump compression refrigeration system of the present invention comprises a compressor, an oil separator, a condenser, a liquid receiver, a refrigerant pump, a throttle valve, and an evaporator connected in sequence. One-way valve A is connected in parallel to bypass the refrigerant pump, and the flow direction of one-way valve A is only allowed from the inlet of the refrigerant pump to the outlet of the refrigerant pump. One-way valve B is connected in parallel to bypass the compressor, and the flow direction of one-way valve B is only allowed from the inlet of the compressor to the outlet of the compressor. The oil outlet of the oil separator is connected to the suction port of the compressor via a capillary tube. An inlet of a solenoid valve is connected between the oil outlet of the oil separator and the inlet of the capillary tube. The outlet of the solenoid valve is connected to the inlet at the top of the liquid receiver (it can be connected to the inlet of the liquid receiver together with the outlet of the condenser, or it can be connected separately to different inlets).

[0055] Example 2, as Figure 2 :

[0056] In some embodiments, a second bypass pipe 102 is also included, one end of which is connected to the interior of the gas-liquid separator 9 so as to discharge the refrigerant liquid inside the gas-liquid separator 9, and the other end of the second bypass pipe 102 is connected to the first bypass pipe 101.

[0057] This invention also utilizes a second bypass pipe to effectively connect the interior of the gas-liquid separator and the first bypass pipe. This allows the refrigerant liquid separated in the gas-liquid separator to be effectively introduced into the receiver tank via the second bypass pipe (in the refrigerant pump refrigeration mode, the liquid refrigerant in the gas-liquid separator mainly enters through the evaporator). This further introduces any refrigerant liquid that has not been completely evaporated in the evaporator into the receiver tank, further reducing the amount of refrigerant liquid entering the condenser inlet, further reducing and avoiding liquid blockage at the condenser inlet, and further improving the heat exchange efficiency of the condenser. Furthermore, it increases the amount of refrigerant liquid entering the receiver tank, enhancing the refrigerant circulation volume during refrigerant pump circulation, and further ensuring the normal and safe operation of the refrigerant pump circulation.

[0058] In some embodiments, one end of the second bypass pipe 102 is connected to the bottom of the gas-liquid separator 9, and the other end of the second bypass pipe 102 is connected to the first bypass pipe 101 at a position between the oil separator 2 and the control valve 8. A one-way valve C13 is also provided on the second bypass pipe 102, which only allows refrigerant fluid to flow from the gas-liquid separator 9 towards the first bypass pipe 101. Embodiment 2 of the present invention, by connecting to the bottom of the gas-liquid separator, effectively introduces refrigerant liquid from the bottom. The connection between the oil separator 2 and the control valve 8 facilitates the control effect of the control valve, preventing the liquid refrigerant discharged from the gas-liquid separator from being uncontrollable and directly entering the liquid storage tank. The one-way valve C only allows flow from the gas-liquid separator to the first bypass pipe, effectively preventing refrigerant in the first bypass pipe from flowing back into the gas-liquid separator, ensuring that the refrigerant liquid in the gas-liquid separator is effectively discharged.

[0059] In Embodiment 2 of the present invention, a one-way valve C is further provided on the gas-liquid separator. The inlet of the one-way valve C is connected to the bottom liquid outlet of the gas-liquid separator, and the outlet of the one-way valve C is connected to the common pipeline of the capillary inlet, the oil outlet of the oil separator, and the solenoid valve inlet.

[0060] The liquid outlet of the gas-liquid separator and the oil outlet of the oil separator are connected to the inlet of the high-pressure storage tank via solenoid valves. Preferably, the outlet of the solenoid valve enters from the top of the storage tank. If the outlet of the solenoid valve enters from the bottom of the storage tank and is submerged below the liquid level inside the tank, it is easily affected by the gravity of the liquid inside the storage tank, making it difficult for the accumulated liquid inside the gas-liquid separator to enter the storage tank, thus affecting the efficiency of liquid bypass. A more optimal arrangement is that the liquid outlet of the gas-liquid separator and the oil outlet of the oil separator are not lower than the top inlet of the storage tank. This allows for smoother bypassing of the accumulated liquid inside the gas-liquid separator or oil separator into the storage tank. The gas-liquid separator includes an inlet pipe (connected to an external inlet) and an outlet pipe (connected to an external outlet, internally U-shaped with a small return oil hole at the bottom of the U-shaped pipe).

[0061] In some embodiments, the position where the second bypass pipe 102 connects to the first bypass pipe 101 is the same as the position where the third pipe 203 connects to the first bypass pipe 101. This is a further preferred connection position for the second bypass pipe of the present invention, that is, the same position as the connection position of the third pipe and the first bypass pipe, simultaneously achieving the different purposes of refrigerant liquid discharge and oil introduction into the gas-liquid separator.

[0062] The present invention also provides a control method for a fluorine pump compression refrigeration system as described above, comprising:

[0063] The detection steps include detecting the operating mode of the refrigerant pump compression refrigeration system and detecting the outlet refrigerant temperature and inlet refrigerant temperature of the evaporator 5.

[0064] The judgment step involves determining whether the operating mode of the refrigerant pump compression refrigeration system is compression refrigeration mode or refrigerant pump refrigeration mode; and when the difference between the refrigerant temperature at the outlet of the evaporator and the refrigerant temperature at the inlet of the evaporator is less than or equal to a preset value, it is determined that the refrigerant liquid in the evaporator 5 has not completely evaporated, and the refrigerant gas at the outlet of the evaporator carries the refrigerant liquid; when the difference between the refrigerant temperature at the outlet of the evaporator and the refrigerant temperature at the inlet of the evaporator is greater than the preset value, it is determined that the refrigerant liquid in the evaporator 5 has completely evaporated;

[0065] The control steps are as follows: when the operating mode of the refrigerant pump compression refrigeration system is the refrigerant pump refrigeration mode: and when it is determined that the refrigerant liquid in the evaporator 5 has not completely evaporated, the control valve 8 is opened; and when it is determined that the refrigerant liquid in the evaporator 5 has completely evaporated, the control valve 8 is closed.

[0066] The control method of the present invention preferably uses the temperature difference between the inlet and outlet of the evaporator to determine whether evaporation is complete. If the temperature difference is greater than a preset value, it indicates that evaporation is complete. At this time, there is little or almost no refrigerant liquid in the oil separator and / or gas-liquid separator, which will not cause liquid blockage at the inlet of the condenser. There is sufficient refrigerant in the system circulation loop. Therefore, the control valve is closed at this time, and there is no need to bypass the refrigerant to the liquid receiver through the first bypass pipeline. However, if the temperature difference is less than or equal to the preset value, it indicates that the refrigerant in the evaporator is not completely evaporated. This will result in a certain or a large amount of refrigerant liquid at the outlet of the evaporator. The refrigerant liquid will enter the oil separator and the gas-liquid separator, causing liquid blockage at the inlet of the condenser and low refrigerant in the liquid receiver. At this time, the control valve needs to be opened so that the refrigerant liquid in the oil separator (more preferably, a gas-liquid separator is added) can smoothly enter the liquid receiver. This preferably reduces the amount of refrigerant liquid entering the condenser, reduces or prevents liquid blockage, and effectively ensures that there is sufficient refrigerant entering the liquid receiver, ensuring the normal and safe operation of the refrigerant pump circulation.

[0067] Figure 1 and Figure 2 In medium-compression refrigeration mode, the refrigerant cycle is as follows: compressor → oil separator → condenser → liquid receiver → check valve A → expansion valve → evaporator → gas-liquid separator → compressor. In this mode, the outlet of check valve B is high-temperature, high-pressure refrigerant gas; therefore, check valve B cannot open and is in a reverse, high-pressure shut-off state.

[0068] Figure 1 and Figure 2 In the heat pipe refrigeration mode of the medium-fluid pump, the refrigerant cycle is as follows: Fluorine pump → expansion valve → evaporator → check valve B → oil separator → condenser → liquid receiver → refrigerant pump. In this mode, the outlet pressure of the refrigerant pump is relatively high, and check valve A is in the reverse high-pressure shut-off state.

[0069] In refrigerant pump heat pipe mode, the refrigerant gas at the evaporator outlet may carry a large amount of unevaporated refrigerant liquid. This refrigerant liquid can easily accumulate in the gas pipes before entering the condenser, causing liquid blockage and obstructing the flow of refrigerant gas in certain channels. This affects the uniformity of gas distribution and heat exchange efficiency of the condenser. Therefore, it is necessary to retain the refrigerant liquid at the evaporator outlet to prevent it from returning to the condenser. However, the more refrigerant liquid retained, the less refrigerant liquid remains in the receiver tank, which is very detrimental to the operation of the refrigerant pump. Therefore, the retained refrigerant liquid must be returned to the receiver tank as soon as possible. The liquid bypass control method in the natural cold source refrigerant pump heat pipe refrigeration mode is as follows:

[0070] 1) When the refrigerant temperature at the evaporator outlet is the same as the refrigerant temperature at the evaporator inlet (and / or the middle of the evaporator), or the temperature difference between the inlet and outlet is less than a preset value, it is considered that the refrigerant liquid in the evaporator has not completely evaporated, and the refrigerant gas at the evaporator outlet carries refrigerant liquid. Therefore, refrigerant liquid will be separated and stored in the oil separator. When this temperature condition accumulates for time t1, the solenoid valve is opened for a duration t2 while the refrigerant pump is running, then the solenoid valve is closed and the t1 time is accumulated again.

[0071] In compression refrigeration mode, the solenoid valve remains closed.

[0072] In some embodiments, the control step, when the operating mode is a refrigerant pump refrigeration mode: and when the difference between the refrigerant temperature at the outlet of the evaporator and the refrigerant temperature at the inlet of the evaporator is less than or equal to a preset value for a duration t1, controls the control valve 8 to open while maintaining the refrigerant pump refrigeration mode, and maintains the control valve 8 open for a duration t2; then closes the control valve 8, and re-detects the refrigerant temperature at the outlet of the evaporator 5 and the refrigerant temperature at the inlet of the evaporator 5, and re-accumulates and counts the t1 time. This invention, when the difference between the refrigerant temperature at the outlet of the evaporator and the refrigerant temperature at the inlet of the evaporator is less than or equal to a preset value for a duration t1, can eliminate other interfering factors and accurately determine that the incomplete evaporation of the refrigerant liquid is due to poor evaporation performance of the evaporator. At this time, the control valve opens, achieving the purpose of introducing the refrigerant liquid into the receiver tank, preventing liquid blockage while ensuring sufficient refrigerant circulation in the refrigerant pump mode.

[0073] In the refrigerant pump refrigeration mode, when the above conditions are met, the solenoid valve is opened, and the refrigerant liquid inside the oil separator (and / or the gas-liquid separator) flows directly to the low-pressure liquid storage tank through the bypass pipeline, thereby preventing the refrigerant liquid from entering the condenser, thus overcoming the liquid blockage phenomenon in the gas pipeline, which is conducive to the reliable operation of the refrigerant pump heat pipe cycle and can improve the energy efficiency ratio of the cycle.

[0074] Figure 1 and Figure 2 In the refrigerant pump heat pipe refrigeration mode, the refrigerant liquid inside the gas-liquid separator enters the U-tube through the small oil return hole at the bottom of the U-tube, forming a liquid blockage. However, due to the significant resistance of the capillary tube, the pressure difference between the gas-liquid separator and the liquid receiver is insufficient to drive the refrigerant gas to carry the refrigerant liquid through the capillary tube in the reverse direction and then into the liquid receiver through the solenoid valve. Therefore, it is considered that there is no refrigerant flow in the capillary tube under this condition. Figure 2 The refrigerant liquid in the gas-liquid separator enters the liquid storage tank through the one-way valve C and the solenoid valve, thereby preventing excessive refrigerant liquid from accumulating in the gas-liquid separator.

[0075] Figure 2 Another function of the one-way valve C in the fluorine pump heat pipe refrigeration mode is that when the solenoid valve is not opened, some refrigerant gas enters the gas-liquid separator and passes through the one-way valve C, then enters the oil separator and merges again with the refrigerant gas at the outlet of the one-way valve B. This increases the refrigerant gas flow path and reduces the flow resistance of the refrigerant gas, which is beneficial to improving the energy efficiency ratio of the fluorine pump heat pipe refrigeration cycle.

[0076] In some embodiments, the control step involves closing the control valve 8 when the refrigerant pump compression refrigeration system is operating in compression refrigeration mode. In compression refrigeration mode, since the compressor outlet is connected to the condenser inlet, liquid blockage at the condenser inlet is generally not a problem; therefore, the control valve is closed at this time.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A fluorine pump compression refrigeration system, characterized in that: include: The compressor (1), oil separator (2), condenser (3), liquid receiver (4), evaporator (5), throttle valve (6), and refrigerant pump (7) are connected. The compression cycle circuit includes the circuit formed by connecting the compressor (1), oil separator (2), condenser (3), liquid receiver (4), throttle valve (6), and evaporator (5). The refrigerant pump refrigeration circuit includes the circuit formed by connecting the refrigerant pump (7), evaporator (5), oil separator (2), condenser (3), and liquid receiver (4). When the compression cycle mode is turned on, the compressor (1) is turned on and the refrigerant pump (7) is turned off. When the refrigerant pump refrigeration mode is turned on, the refrigerant pump (7) is turned on and the compressor (1) is turned off. It also includes a first bypass pipe (101) and a control valve (8). One end of the first bypass pipe (101) is connected to the interior of the oil separator (2) so as to introduce refrigerant liquid from the oil separator (2). The other end of the first bypass pipe (101) is connected to the interior of the liquid storage tank (4) so ​​as to introduce refrigerant liquid into the liquid storage tank. The control valve (8) is provided on the first bypass pipe (101). The opening or closing of the control valve (8) can be controlled by the difference between the outlet refrigerant temperature and the inlet refrigerant temperature of the evaporator (5).

2. The fluorine pump compression refrigeration system according to claim 1, characterized in that: The control valve (8) can be opened when the refrigerant liquid in the evaporator (5) is not completely evaporated, so that the first bypass line (101) is connected; the control valve (8) can be closed when the refrigerant liquid in the evaporator (5) is completely evaporated, so that the first bypass line (101) is not connected.

3. The fluorine pump compression refrigeration system according to claim 2, characterized in that: The control valve (8) can be opened when the difference between the refrigerant temperature at the evaporator outlet and the refrigerant temperature at the evaporator inlet is less than or equal to a preset value. At this time, the refrigerant liquid in the evaporator (5) is not completely evaporated, and there is refrigerant liquid inside the oil separator (2). The control valve (8) can be closed when the difference between the refrigerant temperature at the evaporator outlet and the refrigerant temperature at the evaporator inlet is greater than a preset value. At this time, the refrigerant liquid in the evaporator (5) is completely evaporated.

4. The fluorine pump compression refrigeration system according to any one of claims 1-3, characterized in that: One end of the first bypass pipe (101) is connected to the bottom of the inside of the oil separator (2), and the other end of the first bypass pipe (101) is connected from the top of the liquid storage tank (4) to the inside of the liquid storage tank (4). The other end of the first bypass pipe (101) is also located above the liquid level inside the liquid storage tank (4).

5. The fluorine pump compression refrigeration system according to any one of claims 1-3, characterized in that: It also includes a gas-liquid separator (9), a first pipeline (201), a second pipeline (202) and a third pipeline (203). One end of the first pipeline (201) is connected to the outlet of the evaporator (5) and the other end is connected to the interior of the gas-liquid separator (9). One end of the second pipeline (202) is connected to the interior of the gas-liquid separator (9) and the other end is connected to the suction port of the compressor (1). One end of the third pipeline (203) is connected to the second pipeline (202) and the other end is connected to the first bypass pipeline (101).

6. The fluorine pump compression refrigeration system according to claim 5, characterized in that: The third pipeline (203) is connected to the first bypass pipeline (101) at a position between the oil separator (2) and the control valve (8); a throttling device (10) is provided on the third pipeline (203).

7. The fluorine pump compression refrigeration system according to claim 5, characterized in that: It also includes a fourth pipeline (204) and a fifth pipeline (205). One end of the fourth pipeline (204) is connected to the outlet of the compressor (1) and the other end is connected to the interior of the oil separator (2). One end of the fifth pipeline (205) is connected to the first pipeline (201) and the other end is connected to the fourth pipeline (204). A one-way valve B (11) is provided on the fifth pipeline (205). The one-way valve B (11) can only allow fluid to flow from the first pipeline (201) to the fourth pipeline (204). It also includes a sixth pipeline (206) and a one-way valve A (12). The sixth pipeline (206) is connected in parallel at both ends of the fluorine pump (7). The one-way valve A (12) can only allow fluid to flow from the inlet end of the fluorine pump (7) through the sixth pipeline (206) to the outlet end of the fluorine pump (7).

8. The fluorine pump compression refrigeration system according to claim 5, characterized in that: It also includes a second bypass pipe (102), one end of which is connected to the interior of the gas-liquid separator (9) so as to discharge the refrigerant liquid inside the gas-liquid separator (9), and the other end of the second bypass pipe (102) is connected to the first bypass pipe (101).

9. The fluorine pump compression refrigeration system according to claim 8, characterized in that: One end of the second bypass pipe (102) is connected to the bottom of the gas-liquid separator (9), and the other end of the second bypass pipe (102) is connected to the first bypass pipe (101) at a position between the oil separator (2) and the control valve (8). A one-way valve C (13) is also provided on the second bypass pipe (102). The one-way valve C (13) can only allow refrigerant fluid to flow from the gas-liquid separator (9) toward the first bypass pipe (101).

10. The fluorine pump compression refrigeration system according to claim 9, characterized in that: The position where the second bypass pipe (102) connects to the first bypass pipe (101) is the same position where the third pipe (203) connects to the first bypass pipe (101).

11. A control method for a fluorine pump compression refrigeration system as described in any one of claims 1-10, characterized in that: include: The detection steps include detecting the operating mode of the fluorine pump compression refrigeration system and detecting the outlet refrigerant temperature and inlet refrigerant temperature of the evaporator (5); The judgment step is to determine whether the operating mode of the fluorine pump compression refrigeration system is compression refrigeration mode or fluorine pump refrigeration mode; and when the difference between the outlet refrigerant temperature of the evaporator and the inlet refrigerant temperature of the evaporator is less than or equal to a preset value, it is determined that the refrigerant liquid in the evaporator (5) has not been completely evaporated and the refrigerant gas at the outlet of the evaporator carries the refrigerant liquid; when the difference between the outlet refrigerant temperature of the evaporator and the inlet refrigerant temperature of the evaporator is greater than a preset value, it is determined that the refrigerant liquid in the evaporator (5) has been completely evaporated. Control steps: When the operating mode of the fluorine pump compression refrigeration system is fluorine pump refrigeration mode: and when it is determined that the refrigerant liquid in the evaporator (5) has not completely evaporated, control the control valve (8) to open; and when it is determined that the refrigerant liquid in the evaporator (5) has completely evaporated, control the control valve (8) to close.

12. The control method according to claim 11, characterized in that: In the control steps, when the operating mode is the refrigerant pump refrigeration mode: and when the difference between the outlet refrigerant temperature of the evaporator and the inlet refrigerant temperature of the evaporator is less than or equal to a preset value for a duration of t1, the control valve (8) is opened while maintaining the refrigerant pump refrigeration mode, and the control valve (8) is kept open for a duration of t2; then the control valve (8) is closed, and the outlet refrigerant temperature of the evaporator (5) and the inlet refrigerant temperature of the evaporator (5) are detected again, and the t1 time is accumulated and counted again.

13. The control method according to claim 11, characterized in that: In the control step, when the operating mode of the fluorine pump compression refrigeration system is compression refrigeration mode, the control valve (8) is controlled to close.

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