Air energy refrigeration and variable flow control system and method thereof

Abstract

This invention discloses a control system and method for air-source heat pump refrigeration and variable flow rate. The control system includes a storage tank, a compressor, a first air-source heat exchanger, a second air-source heat exchanger, a refrigerant heat exchanger, a first expansion valve, and a second expansion valve. The outlet of the storage tank is connected to the low-pressure inlet of the compressor via a pipe sequentially equipped with the first expansion valve and the first air-source heat exchanger. The high-pressure outlet of the compressor is connected to the inlet of the second air-source heat exchanger via a pipe. The outlet of the second air-source heat exchanger is connected in parallel with both the inlet of the storage tank and the inlet of the refrigerant heat exchanger via pipes, and a second expansion valve is installed at the inlet of the refrigerant heat exchanger. The outlet of the refrigerant heat exchanger is connected to the low-pressure inlet of the compressor via a pipe. This invention, through improvements, forms a technical solution that effectively maintains a high energy efficiency ratio and saves electricity. It also has advantages such as low operating costs, simple equipment structure, energy saving, and environmental protection, making it suitable for widespread use.

Description

Technical Field

[0001] This invention relates to the field of air conditioning and refrigeration technology, specifically to a control system and method for air-source cooling and variable flow. Background Technology

[0002] There are four main types of artificial refrigeration: phase change refrigeration, gas expansion refrigeration, vortex tube refrigeration, and thermoelectric refrigeration, each with its own characteristics. Phase change refrigeration is a liquid vaporization refrigeration method, where the liquid absorbs heat during its vaporization process to achieve cooling. Increasing the subcooling of the liquid refrigerant in phase change refrigeration technology can increase the cooling capacity and improve the energy efficiency ratio. Gas expansion refrigeration utilizes the adiabatic expansion of a high-pressure gaseous or supercritical refrigerant to obtain a low-temperature refrigerant. The heat absorbed during the reheating process of the expanded low-temperature refrigerant then cools the refrigerant, while the refrigerant completely vaporizes during reheating. The enthalpy change during the refrigerant's throttling expansion process determines the cooling capacity; increasing the enthalpy change of the refrigerant can increase the cooling capacity and improve the energy efficiency ratio.

[0003] There are many existing refrigeration systems, but most of them cannot allow the refrigerant to change its mass flow rate according to different operating conditions during closed operation. As a result, they cannot maintain a high energy efficiency ratio, that is, they are not energy-saving enough. Therefore, there is still room for improvement. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of this invention is to provide a control system and method for air-source cooling and variable flow, which, through improvements, forms a technical solution that can effectively maintain a high energy efficiency ratio and save electricity. It also has the advantages of low operating costs, simple equipment structure, energy saving and environmental protection. At the same time, it also solves other problems in the prior art.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] An air-source heat pump cooling and variable flow control system, comprising:

[0007] Storage tank, compressor, first air source heat exchanger, second air source heat exchanger, refrigerant heat exchanger, first expansion valve and second expansion valve;

[0008] The outlet of the storage tank is connected to the low-pressure inlet of the compressor via a pipe that is sequentially equipped with the first expansion valve and the first air-source heat exchanger, so as to convert the refrigerant output from the storage tank into a superheated gaseous low-temperature refrigerant for input into the compressor.

[0009] The high-pressure outlet of the compressor is connected to the inlet of the second air-source heat exchanger via a pipeline, so as to convert the superheated gaseous low-temperature refrigerant output from the first air-source heat exchanger into a high-pressure high-temperature refrigerant for input into the second air-source heat exchanger.

[0010] The outlet of the second air source heat exchanger is connected in parallel with the inlet of the storage tank and the inlet of the refrigerant heat exchanger via pipes. A second expansion valve is provided at the inlet of the refrigerant heat exchanger to convert the high-pressure, high-temperature refrigerant output by the compressor into a high-pressure, room-temperature refrigerant. The high-pressure, room-temperature refrigerant can then be input into the storage tank for storage or expanded by throttling through the second expansion valve. It absorbs heat from the refrigerant in the refrigerant heat exchanger and becomes a gaseous refrigerant before being discharged from the refrigerant heat exchanger.

[0011] The outlet of the refrigerant heat exchanger is connected to the low-pressure inlet of the compressor via a pipeline, so that the gaseous refrigerant discharged from the refrigerant heat exchanger can be pressurized by the compressor and recycled or fed into the storage tank for storage.

[0012] Additional structures for the above technical solutions also include the following:

[0013] As a specific embodiment, a pipe equipped with a first solenoid valve is connected between the pipe connecting the outlet of the refrigerant heat exchanger to the compressor and the pipe connecting the outlet of the storage tank to the inlet of the first air source heat exchanger, for inputting the refrigerant in the refrigerant heat exchanger into the first air source heat exchanger; a second solenoid valve is also provided on the pipe connecting the outlet of the refrigerant heat exchanger to the compressor for cooperating with the first solenoid valve; a first control valve and a second control valve are respectively provided at the outlet and inlet of the storage tank.

[0014] As a specific embodiment, the refrigerant heat exchanger is provided in two or more and arranged in parallel, and a second expansion valve is provided at the inlet of each refrigerant heat exchanger.

[0015] As a specific embodiment, a proportional valve is also provided at the outlet of the refrigerant heat exchanger to control the opening degree and adjust the refrigerant flow rate to control the cooling capacity.

[0016] As a specific embodiment, the pressure setting value of the low-pressure inlet end of the compressor is between 0.15MPa and 4MPa, and the pressure setting value of the high-pressure outlet end of the compressor is between 3.5MPa and 12MPa.

[0017] Furthermore, pressure sensors are respectively installed at the low-pressure inlet end and the high-pressure outlet end of the compressor.

[0018] As a specific embodiment, when the refrigerant mass of the control system needs to be reduced due to a decrease in the required cooling capacity, the excess refrigerant is pressurized by the compressor and then flows into the storage tank for storage.

[0019] When the control system needs to increase the mass of refrigerant due to an increase in required cooling capacity, the refrigerant in the storage tank is output, and the refrigerant flows into the low-pressure inlet of the compressor after being vaporized through the first expansion valve and the first air-source heat exchanger, so as to replenish the refrigerant mass required by the control system.

[0020] The present invention also provides a control method for air-source cooling and variable flow rate, employing the air-source cooling and variable flow rate control system described above, comprising the following steps:

[0021] S1. Start the control system and start the compressor. When the pressure at the high-pressure outlet of the compressor is lower than the set value, the refrigerant in the storage tank flows out and passes through the first expansion valve and the first air heat exchanger to vaporize and convert into a superheated gaseous low-temperature refrigerant, which is then input into the low-pressure inlet of the compressor to maintain the pressure at the high-pressure outlet of the compressor at the set value, and at the same time maintain the pressure at the low-pressure inlet of the compressor at the set value.

[0022] S2. The superheated gaseous low-temperature refrigerant is pressurized by the compressor to become a high-pressure high-temperature refrigerant, and then the high-pressure high-temperature refrigerant enters the second air-source heat exchanger.

[0023] S3. The high-pressure high-temperature refrigerant entering the second air source heat exchanger is transformed into high-pressure room-temperature refrigerant by releasing heat to the air in the environment. Then, the high-pressure room-temperature refrigerant enters the second expansion valve.

[0024] S4. After the high-pressure room-temperature refrigerant enters the second expansion valve, it is converted into a low-temperature refrigerant due to the JT effect and enters the heat exchanger.

[0025] S5. After the low-temperature refrigerant enters the refrigerant heat exchanger, it exchanges heat with the refrigerant on the outer surface of the refrigerant heat exchanger. The refrigerant releases heat to the refrigerant to achieve cooling of the refrigerant. The low-temperature refrigerant absorbs the heat from the refrigerant and then reheats and completely vaporizes.

[0026] S6. The gaseous refrigerant discharged from the heat exchanger is then pressurized by the compressor through a pipeline and recycled after becoming a high-pressure, high-temperature refrigerant.

[0027] S7. When the pressure at the high-pressure outlet of the compressor does not reach the set value, the storage tank continues to release refrigerant; when the pressure at the high-pressure outlet of the compressor reaches the set value, the outlet of the storage tank stops releasing refrigerant.

[0028] S8. When the pressure at the high-pressure outlet of the compressor exceeds the set value, the excess refrigerant flows into the inlet of the storage tank until the pressure at the high-pressure outlet of the compressor reaches the set value, at which point the refrigerant flow into the inlet of the storage tank stops.

[0029] As a specific embodiment, in step S1, after the compressor starts operating, when the pressure at the high-pressure outlet of the compressor is lower than the set value, the refrigerant in the refrigerant heat exchanger is first discharged, and the refrigerant is vaporized through the first expansion valve and the first air-source heat exchanger into a superheated gaseous refrigerant, which is then input into the low-pressure inlet of the compressor. If the pressure inside the refrigerant heat exchanger reaches the set value but the pressure at the high-pressure outlet of the compressor is still lower than the set value, the refrigerant is replenished by flowing out of the storage tank. In the subsequent refrigeration process of the control system, the gaseous refrigerant discharged from the refrigerant heat exchanger is directly input into the compressor and no longer flows out into the first expansion valve and the first air-source heat exchanger.

[0030] As a specific embodiment, when the number of refrigerant heat exchangers used is increased, the pressure at the high-pressure outlet of the compressor is lower than the set value, thereby opening the outlet of the storage tank and releasing refrigerant for filling, until the pressure at the high-pressure outlet of the compressor reaches the set value and stops.

[0031] After the number of refrigerant heat exchangers used is reduced, the pressure at the high-pressure outlet of the compressor is greater than the set value, thereby opening the inlet of the storage tank and allowing excess refrigerant to flow in until the pressure at the high-pressure outlet of the compressor reaches the set value and stops.

[0032] The beneficial effects of this invention are as follows:

[0033] (i) The refrigerant of this invention is vaporized by a first expansion valve and a first air-source heat exchanger and then input into the compressor. The refrigerant is pressurized by increasing the gaseous refrigerant pressure at the compressor inlet, thereby improving the energy efficiency ratio of the refrigerant circulation system. Then, the refrigerant is cooled by a second air-source heat exchanger, thus turning the refrigerant into a high-pressure room-temperature refrigerant. Then, the high-pressure room-temperature refrigerant is depressurized and adiabatically expanded into a low-temperature refrigerant by the second expansion valve, thereby increasing the enthalpy change value of the refrigerant during refrigeration to obtain a higher energy efficiency ratio. After the refrigerant enters the refrigerant heat exchanger, the refrigeration purpose of the refrigerant is finally achieved through the refrigerant heat exchanger. Therefore, it has a high energy efficiency ratio, low operating cost, simple equipment structure, and is energy-saving and environmentally friendly.

[0034] (ii) In this invention, after the refrigerant is heated by the heat exchanger, it is pressurized and cooled again by the compressor and the second air-source heat exchanger before being fed into the second expansion valve and the heat exchanger, thus achieving recycling and effectively reducing the operating cost of the control system.

[0035] (III) This invention is equipped with two air-source heat exchangers. One of them is used to vaporize the refrigerant by absorbing heat from the ambient air, eliminating the need for a gas-liquid separator for the refrigerant and preventing unvaporized liquid refrigerant from entering the compressor and causing damage. The other is used to cool the refrigerant by releasing heat to the ambient air. The two air-source heat exchangers, together with the piping and storage tank, ensure that the pressure at both the low-pressure inlet and high-pressure outlet of the compressor can be maintained at the set value. When the pressure at the high-pressure outlet of the compressor is lower than the set value, the storage tank continuously releases refrigerant to compensate for the pressure until the pressure at the high-pressure outlet of the compressor reaches the set value and then stops releasing refrigerant. When the pressure at the high-pressure outlet of the compressor is higher than the set value, the excess mass of refrigerant is used to flow into the storage tank using the pressure difference to reduce the pressure at the high-pressure outlet of the compressor until the pressure at the high-pressure outlet of the compressor reaches the set value and then the storage tank stops releasing refrigerant. If the pressure at the high-pressure outlet of the compressor remains at the set value, the storage tank does not need to release or release refrigerant. Therefore, the control system of the present invention can adjust the refrigerant flow rate in real time according to the real-time usage, such as when the number of refrigerant heat exchangers used increases or decreases. This realizes the change of refrigerant mass flow rate under different operating conditions in closed operation. At the same time, it enables the compressor to maintain a high energy efficiency ratio of the control system while ensuring that the set pressure at both ends remains unchanged, thus achieving the purpose of saving electricity.

[0036] (iv) This invention sets up a pipe between the pipe connecting the outlet of the refrigerant heat exchanger to the compressor and the pipe connecting the outlet of the storage tank to the inlet of the first air-source heat exchanger, and then sets up a first solenoid valve and a second solenoid valve that cooperate with each other. Since the refrigerant in the refrigerant heat exchanger needs to be vaporized through the first expansion valve and the first air-source heat exchanger before it can be input into the compressor, it can be used to remove a small amount of refrigerant, such as liquid refrigerant, that is stored in the refrigerant heat exchanger when the control system is just turned on, so as to avoid the mixing of liquid and gaseous refrigerant in the compressor and damage to the compressor, thus extending the service life of the compressor. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the control system for air-source cooling and variable flow of the present invention.

[0038] Figure 2 This is a schematic diagram of the process principle of an air-source cooling and variable flow control method according to the present invention.

[0039] Figure label:

[0040] 1. Storage tank; 2. Compressor; 3. First air source heat exchanger; 4. Second air source heat exchanger; 5. Refrigerant heat exchanger; 6. First expansion valve; 7. Second expansion valve; 8. First solenoid valve; 9. Second solenoid valve; 10. First control valve; 11. Second control valve; 12. Proportional valve; 13. Check valve; 14. Third solenoid valve. Detailed Implementation

[0041] The invention will be further described below with reference to the accompanying drawings and specific embodiments. The following description is merely exemplary and does not limit the scope of protection of the invention.

[0042] Example 1:

[0043] refer to Figure 1 An air-source heat pump refrigeration and variable flow control system includes: a storage tank 1, a compressor 2, a first air-source heat exchanger 3, a second air-source heat exchanger 4, a refrigerant heat exchanger 5, a first expansion valve 6, and a second expansion valve 7.

[0044] The storage tank 1 is used to supply refrigerant to the control system, such as R744 or oil-free carbon dioxide refrigerant. The compressor 2 helps to transfer excess refrigerant from the pipeline into the storage tank 1. In this control system, the first air source heat exchanger 3 and the second air source heat exchanger 4 are outdoor units, while the refrigerant heat exchanger 5 is the indoor unit. Both the first and second air source heat exchangers 3 and 4 include an outdoor unit, a silent fan with adjustable airflow, a refrigerant heat exchanger, two ambient air temperature probes installed at the outlet and inlet of the air source heat exchanger respectively, and a refrigerant pressure gauge installed inside the refrigerant heat exchanger tubes. The refrigerant heat exchanger 5 is a sealed structure, internally equipped with a heat exchanger and a pressure gauge; the refrigerant transfers cooling capacity through the tube walls of the heat exchanger.

[0045] Carbon dioxide is a newly emerging natural refrigerant. From an environmental perspective, besides water and air, it is one of the most environmentally friendly refrigerants. Moreover, supercritical carbon dioxide expansion refrigeration is a highly efficient refrigeration method. In addition, carbon dioxide also has good safety and chemical stability.

[0046] In this control system, such as Figure 1As shown, the outlet of the storage tank 1 is connected to the low-pressure inlet of the compressor 2 through a pipe equipped with a first expansion valve 6 and a first air source heat exchanger 3 in sequence, so as to convert the carbon dioxide refrigerant output from the storage tank 1 into a gaseous low-temperature carbon dioxide refrigerant with a certain degree of superheat and input it into the compressor 2. The first expansion valve 6 can be used to expand and reduce pressure, so that the carbon dioxide refrigerant output from the storage tank 1 first passes through the first expansion valve 6, and then enters the first air source heat exchanger 3 to absorb heat from the outdoor environment and vaporize, and finally become a gaseous low-temperature refrigerant. That is, the carbon dioxide refrigerant output from the storage tank 1 is vaporized.

[0047] The high-pressure outlet of compressor 2 is connected to the inlet of the second air source heat exchanger 4 through a pipeline, so as to convert the gaseous low-temperature carbon dioxide refrigerant with a certain degree of superheat output from the first air source heat exchanger 3 into a gaseous or supercritical high-pressure high-temperature carbon dioxide refrigerant, which is then input into the second air source heat exchanger 4.

[0048] The outlet of the second air source heat exchanger 4 is connected in parallel with the inlet of the storage tank 1 and the inlet of the refrigerant heat exchanger 5 via pipes. A second expansion valve 7 is installed at the inlet of the refrigerant heat exchanger 5 to convert the gaseous or supercritical high-pressure high-temperature carbon dioxide refrigerant output by the compressor into high-pressure room-temperature carbon dioxide refrigerant. The high-pressure room-temperature carbon dioxide refrigerant can then be input into the storage tank 1 for storage or expanded by throttling through the second expansion valve 7. After absorbing heat from the refrigerant in the refrigerant heat exchanger 5, it is discharged from the refrigerant heat exchanger as a gaseous refrigerant. For example, the high-pressure, high-temperature carbon dioxide refrigerant output by compressor 2 is introduced into the second air-source heat exchanger 4 and converted into high-pressure, room-temperature carbon dioxide refrigerant by releasing heat to the outdoor air. During normal operation, this high-pressure, room-temperature carbon dioxide refrigerant is introduced into the second expansion valve 7 and converted into low-temperature carbon dioxide refrigerant due to the JT effect. It is then introduced into the refrigerant heat exchanger 5 to absorb heat from the refrigerant and is discharged as a gaseous refrigerant. If the pressure at the high-pressure outlet of compressor 2 exceeds a predetermined value, the inlet of storage tank 1 is opened, and excess mass of high-pressure, room-temperature carbon dioxide refrigerant is introduced into storage tank 1 using the pressure difference until the pressure at the high-pressure outlet of compressor 2 reaches the predetermined value.

[0049] The outlet of the refrigerant heat exchanger 5 is connected to the low-pressure inlet of the compressor 2 via a pipe. The gaseous carbon dioxide refrigerant discharged from the refrigerant heat exchanger 5 is pressurized by the compressor 2 and converted into high-pressure, high-temperature refrigerant. Then, it is fed into the refrigerant heat exchanger 5 through the second air-source heat exchanger 4 and the second expansion valve 7, thus achieving recycling. Alternatively, after the compressor 2 pressurizes the carbon dioxide refrigerant, if the pressure at the high-pressure outlet of the compressor 2 exceeds a predetermined value, the refrigerant is fed into the storage tank 1 through the second air-source heat exchanger 4 for storage.

[0050] A pipe equipped with a first solenoid valve 8 is connected between the pipe connecting the outlet of the refrigerant heat exchanger 5 to the compressor 2 and the pipe connecting the outlet of the storage tank 1 to the inlet of the first air source heat exchanger 3. That is, the pipe connecting the outlet of the refrigerant heat exchanger 5 to the compressor 2 and the pipe connecting the outlet of the storage tank 1 to the inlet of the first air source heat exchanger 3 are connected in parallel to facilitate the input of carbon dioxide refrigerant from the refrigerant heat exchanger 5 into the first air source heat exchanger 3. A second solenoid valve 9 is also provided on the pipe connecting the outlet of the refrigerant heat exchanger 5 to the compressor 2 for cooperating with the first solenoid valve 8. A first control valve 10 and a second control valve 11 are respectively provided at the outlet and inlet of the storage tank 1. By installing a pipeline with a first solenoid valve 8, the compressor 2 can initially extract a small amount of gaseous or liquid refrigerant remaining in the refrigerant heat exchanger 5 at the start of the control system. At this time, the second solenoid valve 9 is closed, while the first solenoid valve 8 is open. This prevents the extracted refrigerant from the refrigerant heat exchanger 5 from directly entering the compressor 2 through the second solenoid valve 9. The extracted refrigerant will then vaporize after passing through the first expansion valve 6 and the first air-source heat exchanger 3 before finally entering the compressor 2, thus ensuring that no liquid refrigerant remains at the inlet of the compressor 2. The refrigerant enters the compressor 2 to prevent damage and extend its lifespan. If the pressure inside the refrigerant heat exchanger 5 reaches the set value but the pressure at the high-pressure outlet of the compressor 2 does not, the first control valve 10 opens to replenish the refrigerant from the storage tank 1. Simultaneously, the first solenoid valve 8 closes and the second solenoid valve 9 opens, allowing the refrigerant in the storage tank 1 to vaporize via the first expansion valve 6 and the first air heat exchanger 3 before entering the compressor 2. This continues until the pressure at the high-pressure outlet of the compressor 2 reaches the set value, at which point the first control valve 10 stops. Therefore, this structure allows for the removal of small amounts of liquid refrigerant from the refrigerant heat exchanger 5 when the control system is first activated, preventing liquid refrigerant from entering the compressor 2 and damaging it, thus extending its lifespan.

[0051] To facilitate the control of the flow of carbon dioxide refrigerant in storage tank 1, the first control valve 10 and the second control valve 11 can be proportional valves to improve the accuracy of flow control.

[0052] To facilitate the control of carbon dioxide refrigerant, a third solenoid valve 14 for controlling the opening and closing of the pipeline can also be installed on the pipeline between the first air source heat exchanger 3 and the first expansion valve 6.

[0053] Two or more refrigerant heat exchangers 5 can be installed in parallel so that people can increase or decrease the number of refrigerant heat exchangers 5 at any time to increase or decrease the cooling capacity. A second expansion valve 7 is installed at the inlet of each refrigerant heat exchanger 5.

[0054] A proportional valve 12 is also provided at the outlet of the refrigerant heat exchanger 5 to adjust the refrigerant flow rate to control the cooling capacity, so that the refrigerant temperature at the outlet of the refrigerant heat exchanger 5 is maintained at the set value and the refrigerant temperature will not fluctuate due to changes in the refrigerant mass flow rate or volume flow rate.

[0055] A one-way valve 13 is also installed on the pipe connecting the outlet of the refrigerant heat exchanger 5 to the compressor 2 to ensure the flow direction of the refrigerant and prevent backflow. Of course, for the same purpose of ensuring the flow direction of the refrigerant and preventing backflow, a one-way valve 13 can also be installed at the inlet and outlet of the compressor 2.

[0056] In this embodiment, the pressure setting value of the low-pressure inlet end of the compressor 2 is between 0.15MPa and 4MPa, while the pressure setting value of the high-pressure outlet end of the compressor 2 is between 3.5MPa and 12MPa.

[0057] Pressure sensors are also installed at the low-pressure inlet and high-pressure outlet of compressor 2 to detect the pressure at the corresponding positions in real time and accurately.

[0058] When the control system needs to reduce the mass of carbon dioxide refrigerant due to a decrease in required cooling capacity, the excess carbon dioxide refrigerant is pressurized by compressor 2 and then flows into storage tank 1 for storage. When the control system needs to increase the mass of carbon dioxide refrigerant due to an increase in required cooling capacity, the carbon dioxide refrigerant in storage tank 1 is output, and the carbon dioxide refrigerant flows into the low-pressure inlet end of compressor 2 after vaporization through first expansion valve 6 and first air-source heat exchanger 3, in order to replenish the refrigerant required by the control system.

[0059] The refrigerant in the refrigerant heat exchanger can be a gaseous refrigerant or a liquid refrigerant. The gaseous refrigerant can be air, nitrogen or argon, and the liquid refrigerant can be water, brine, ethylene glycol or propylene glycol solution.

[0060] Example 2:

[0061] refer to Figure 2 This embodiment provides a control method for air-source cooling and variable flow rate, which adopts the air-source cooling and variable flow rate control system of Embodiment 1, and includes the following steps:

[0062] S1. Start the control system and start the compressor 2. When the pressure at the high-pressure outlet of the compressor 2 is lower than the set value, the carbon dioxide refrigerant in the storage tank 1 flows out. The carbon dioxide refrigerant is vaporized through the first expansion valve 6 and the first air heat exchanger 3 and converted into gaseous low-temperature carbon dioxide refrigerant with a certain degree of superheat and input into the low-pressure inlet of the compressor 2 to keep the pressure at the high-pressure outlet of the compressor 2 at the set value, and at the same time to keep the pressure at the low-pressure inlet of the compressor 2 not lower than the set value. That is, at this time the first solenoid valve 8 is in the closed state and the second solenoid valve 9 is in the open state.

[0063] S2. The gaseous low-temperature carbon dioxide refrigerant with a certain degree of superheat is pressurized by compressor 2 and becomes gaseous or supercritical high-pressure high-temperature carbon dioxide refrigerant. Then, the gaseous or supercritical high-pressure high-temperature carbon dioxide refrigerant enters the second air source heat exchanger 4.

[0064] S3. The gaseous or supercritical high-pressure high-temperature carbon dioxide refrigerant entering the second air source heat exchanger 4 is transformed into gaseous or supercritical high-pressure room-temperature carbon dioxide refrigerant by releasing heat to the air in the environment. Then, the gaseous or supercritical high-pressure room-temperature carbon dioxide refrigerant enters the second expansion valve 7.

[0065] S4. After gaseous or supercritical high-pressure room-temperature carbon dioxide refrigerant enters the second expansion valve 7, it is transformed into low-temperature carbon dioxide refrigerant due to the JT effect. Then, the low-temperature carbon dioxide refrigerant enters the corresponding refrigerant heat exchanger 5.

[0066] S5. After the low-temperature carbon dioxide refrigerant enters the refrigerant heat exchanger 5, it exchanges heat with the refrigerant on the outer surface of the refrigerant heat exchanger 5, so that the refrigerant releases heat to the carbon dioxide refrigerant to achieve cooling of the refrigerant. The low-temperature refrigerant absorbs the heat of the refrigerant and then reheats and completely vaporizes.

[0067] S6. The gaseous carbon dioxide refrigerant discharged through the refrigerant heat exchanger 5 is then pressurized by the compressor 2 through the pipeline into a high-pressure, high-temperature carbon dioxide refrigerant for recycling.

[0068] S7. When the pressure at the high-pressure outlet of compressor 2 does not reach the set value, storage tank 1 continues to release carbon dioxide refrigerant; when the pressure at the high-pressure outlet of compressor 2 reaches the set value, the outlet of storage tank 1 stops releasing carbon dioxide refrigerant.

[0069] S8. When the pressure at the high-pressure outlet of compressor 2 exceeds the set value, the excess carbon dioxide refrigerant flows into the inlet of storage tank 1 until the pressure at the high-pressure outlet of compressor 2 reaches the set value, at which point the flow of carbon dioxide refrigerant into storage tank 1 stops.

[0070] Preferably, in step S1, after the compressor 2 starts operating, the first solenoid valve 8 opens and the second solenoid valve 9 closes. When the pressure at the high-pressure outlet of the compressor 2 is lower than the set value, a small amount of refrigerant remaining in the refrigerant heat exchanger 5 (e.g., liquid refrigerant) is first allowed to flow out. The refrigerant is then vaporized through the first expansion valve 6 and the first air-source heat exchanger 3 and converted into gaseous refrigerant with a certain degree of superheat, which is then input into the low-pressure inlet of the compressor 2. This prevents the refrigerant extracted from the refrigerant heat exchanger 5 from directly entering the compressor 2 through the second solenoid valve 9. If the pressure inside the refrigerant heat exchanger 5 reaches the set value but the pressure at the high-pressure outlet of the compressor 2 is still lower than the set value, refrigerant is supplied by the storage tank 1. In the subsequent control system cooling process, the gaseous refrigerant in the refrigerant heat exchanger 5 is directly input into the compressor 2 and no longer flows out into the first expansion valve 6 and the first air-source heat exchanger 3. That is, at this time, the first solenoid valve 8 is closed and the second solenoid valve 9 is open.

[0071] Preferably, when the number of refrigerant heat exchangers 2 used increases (i.e. when the number of open units increases), the pressure at the high-pressure outlet of compressor 2 will be lower than the set value, thereby opening the outlet of storage tank 1 and releasing refrigerant for filling, until the pressure at the high-pressure outlet of compressor 2 reaches the set value and stops.

[0072] When the number of refrigerant heat exchangers 5 used decreases (i.e., when the number of shut-off units increases), the pressure at the high-pressure outlet of compressor 2 exceeds the set value, thereby opening the inlet of storage tank 1 and allowing excess refrigerant to flow in until the pressure at the high-pressure outlet of compressor 2 reaches the set value and stops.

[0073] The pressure setting value of the low-pressure inlet end of the compressor 2 is between 0.15MPa and 4MPa, while the pressure setting value of the high-pressure outlet end of the compressor is between 3.5MPa and 12MPa.

[0074] Pressure sensors are used to detect the pressure at the low-pressure inlet and high-pressure outlet of compressor 2.

[0075] The refrigerant in the refrigerant heat exchanger is a gaseous refrigerant or a liquid refrigerant. The gaseous refrigerant is air, nitrogen, or argon, and the liquid refrigerant is water, brine, ethylene glycol, or propylene glycol solution.

[0076] Other corresponding technical features used to assist in the implementation of the technical solution in this invention can be implemented by those skilled in the art in combination with existing conventional technical means or improved upon them. Other related technical means will not be elaborated here.

[0077] In the description of this specification, the terms "Embodiment 1," "this embodiment," or "specific implementation" indicate that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example; moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in one or more embodiments or examples.

[0078] In the description of this specification, terms such as “connection,” “installation,” “fixation,” “setting,” and “having” are interpreted broadly. For example, “connection” can mean a fixed connection or an indirect connection through an intermediate component without affecting the relationship between components and the technical effect. It can also mean an integral connection or a partial connection. In such cases, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0079] The above description of the embodiments is intended to facilitate understanding and application by those skilled in the art. Those familiar with the art can readily make various modifications to these examples and apply the general principles described herein to other embodiments without creative effort. Therefore, this application is not limited to the above embodiments. Modifications in the following situations should be within the scope of protection of this application: ① New technical solutions implemented based on the technical solution of this invention and combined with existing common knowledge; ② Equivalent substitutions of some features of the technical solution of this invention using known technologies, resulting in the same technical effects as the technical effects of this invention, for example, equivalent substitutions of conventional production equipment and devices used in the process; ③ Extensions based on the technical solution of this invention, where the substantive content of the extended technical solution does not exceed the technical solution of this invention; ④ Solutions that apply the obtained technical means to other related technical fields using equivalent transformations made using the textual description or accompanying drawings of this invention.

Claims

1. A control system for air-source cooling and variable flow, characterized in that, include: Storage tank, compressor, first air source heat exchanger, second air source heat exchanger, refrigerant heat exchanger, first expansion valve and second expansion valve; The outlet of the storage tank is connected to the low-pressure inlet of the compressor via a pipe that is sequentially equipped with the first expansion valve and the first air-source heat exchanger, so as to convert the refrigerant output from the storage tank into a superheated gaseous low-temperature refrigerant for input into the compressor. The high-pressure outlet of the compressor is connected to the inlet of the second air-source heat exchanger via a pipeline, so as to convert the superheated gaseous low-temperature refrigerant output from the first air-source heat exchanger into a high-pressure high-temperature refrigerant for input into the second air-source heat exchanger. The outlet of the second air source heat exchanger is connected in parallel with the inlet of the storage tank and the inlet of the refrigerant heat exchanger via pipes. A second expansion valve is provided at the inlet of the refrigerant heat exchanger to convert the high-pressure, high-temperature refrigerant output by the compressor into a high-pressure, room-temperature refrigerant. The high-pressure, room-temperature refrigerant can then be input into the storage tank for storage or expanded by throttling through the second expansion valve. It absorbs heat from the refrigerant in the refrigerant heat exchanger and becomes a gaseous refrigerant before being discharged from the refrigerant heat exchanger. The outlet of the refrigerant heat exchanger is connected to the low-pressure inlet of the compressor via a pipeline, so that the gaseous refrigerant discharged from the refrigerant heat exchanger can be pressurized by the compressor and recycled or fed into the storage tank for storage.

2. The air-source cooling and variable flow control system according to claim 1, characterized in that: A pipe equipped with a first solenoid valve is also connected between the pipe connecting the outlet of the refrigerant heat exchanger to the compressor and the pipe connecting the outlet of the storage tank to the inlet of the first air source heat exchanger, for inputting the refrigerant in the refrigerant heat exchanger into the first air source heat exchanger. A second solenoid valve for cooperating with the first solenoid valve is also provided on the pipe connecting the outlet of the refrigerant heat exchanger to the compressor. A first control valve and a second control valve are respectively installed at the outlet and inlet of the storage tank.

3. The air-source cooling and variable flow control system according to claim 1, characterized in that: The refrigerant heat exchanger is provided in two or more and is arranged in parallel, and a second expansion valve is provided at the inlet of each refrigerant heat exchanger.

4. The air-source cooling and variable flow control system according to any one of claims 1-3, characterized in that: A proportional valve is also provided at the outlet of the refrigerant heat exchanger to control the opening degree and adjust the refrigerant flow rate to control the cooling capacity.

5. The air-source cooling and variable flow control system according to claim 1, characterized in that: The pressure setting value of the low-pressure inlet end of the compressor is between 0.15MPa and 4MPa, and the pressure setting value of the high-pressure outlet end of the compressor is between 3.5MPa and 12MPa.

6. The air-source cooling and variable flow control system according to claim 5, characterized in that: Pressure sensors are also installed at the low-pressure inlet and high-pressure outlet of the compressor.

7. The air-source cooling and variable flow control system according to claim 1, characterized in that: When the refrigerant mass of the control system needs to be reduced due to a decrease in the required cooling capacity, the excess refrigerant is pressurized by the compressor and then flows into the storage tank for storage. When the control system needs to increase the mass of refrigerant due to an increase in required cooling capacity, the refrigerant in the storage tank is output, and the refrigerant flows into the low-pressure inlet of the compressor after being vaporized through the first expansion valve and the first air-source heat exchanger, so as to replenish the refrigerant mass required by the control system.

8. A method for controlling air-source cooling and variable flow, characterized in that, The control system for air-source heat pump cooling and variable flow as described in any one of claims 1-7 includes the following steps: S1. Start the control system and start the compressor. When the pressure at the high-pressure outlet of the compressor is lower than the set value, the refrigerant in the storage tank flows out and passes through the first expansion valve and the first air heat exchanger to vaporize and convert into a superheated gaseous low-temperature refrigerant, which is then input into the low-pressure inlet of the compressor to maintain the pressure at the high-pressure outlet of the compressor at the set value, and at the same time maintain the pressure at the low-pressure inlet of the compressor at the set value. S2. The superheated gaseous low-temperature refrigerant is pressurized by the compressor to become a high-pressure high-temperature refrigerant, and then the high-pressure high-temperature refrigerant enters the second air-source heat exchanger. S3. The high-pressure high-temperature refrigerant entering the second air source heat exchanger is transformed into high-pressure room-temperature refrigerant by releasing heat to the air in the environment. Then, the high-pressure room-temperature refrigerant enters the second expansion valve. S4. After the high-pressure room-temperature refrigerant enters the second expansion valve, it is converted into a low-temperature refrigerant due to the JT effect and enters the heat exchanger. S5. After the low-temperature refrigerant enters the refrigerant heat exchanger, it exchanges heat with the refrigerant on the outer surface of the refrigerant heat exchanger. The refrigerant releases heat to the refrigerant to achieve cooling of the refrigerant. The low-temperature refrigerant absorbs the heat from the refrigerant and then reheats and completely vaporizes. S6. The gaseous refrigerant discharged from the heat exchanger is then pressurized by the compressor through a pipeline and recycled after becoming a high-pressure, high-temperature refrigerant. S7. When the pressure at the high-pressure outlet of the compressor does not reach the set value, the storage tank continues to release refrigerant; when the pressure at the high-pressure outlet of the compressor reaches the set value, the outlet of the storage tank stops releasing refrigerant. S8. When the pressure at the high-pressure outlet of the compressor exceeds the set value, the excess refrigerant flows into the inlet of the storage tank until the pressure at the high-pressure outlet of the compressor reaches the set value, at which point the refrigerant flow into the inlet of the storage tank stops.

9. The air-source cooling and variable flow control method according to claim 8, characterized in that: In step S1, after the compressor starts operating, when the pressure at the high-pressure outlet of the compressor is lower than the set value, the refrigerant in the refrigerant heat exchanger is first discharged, and the refrigerant is vaporized through the first expansion valve and the first air-source heat exchanger into a superheated gaseous refrigerant, which is then input into the low-pressure inlet of the compressor. If the pressure inside the refrigerant heat exchanger reaches the set value but the pressure at the high-pressure outlet of the compressor is still lower than the set value, the refrigerant is replenished by flowing out of the storage tank. In the subsequent refrigeration process of the control system, the gaseous refrigerant discharged from the refrigerant heat exchanger is directly input into the compressor and no longer flows out into the first expansion valve and the first air-source heat exchanger.

10. The air-source cooling and variable flow control method according to claim 8, characterized in that: As the number of refrigerant heat exchangers increases, the pressure at the high-pressure outlet of the compressor is lower than the set value, thereby opening the outlet of the storage tank and releasing refrigerant for filling, until the pressure at the high-pressure outlet of the compressor reaches the set value and stops. After the number of refrigerant heat exchangers used is reduced, the pressure at the high-pressure outlet of the compressor is greater than the set value, thereby opening the inlet of the storage tank and allowing excess refrigerant to flow in until the pressure at the high-pressure outlet of the compressor reaches the set value and stops.

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