Efficient tank heat exchanger, heat pump unit, oil return control method and storage medium

Abstract

The invention provides an efficient tank heat exchanger, a heat pump unit, an oil return control method and a storage medium, relates to the technical field of heat pumps, and solves the problems of unsmooth circulation of lubricating oil of a compressor and low oil return efficiency of the unit in the related technology. An oil return channel can be formed between the efficient tank heat exchanger and the compressor in the heat pump unit, then the two-way electromagnetic valve is controlled to be opened or closed by detecting the change of the pressure of the compressor, optimization of oil return control of the heat pump unit is achieved, and the oil return efficiency of the heat pump unit is improved. The problem that the lubricating oil of the compressor only flows out and does not flow in due to the factors such as the opening degree of the electronic expansion valve and the solubility of the lubricating oil is solved, so that the lubricating oil can participate in the lubricating process of the action of the compressor, the service life of the compressor is prolonged, and a heat pump unit can still efficiently and reliably operate under the low-temperature heating working condition.

Description

Technical Field

[0001] The present application relates to the field of heat pump technology, and in particular to a high-efficiency tank heat exchanger, a heat pump unit, an oil return control method and a storage medium. Background Art

[0002] Heat pump units are highly efficient and energy-saving, and are therefore widely used in heating, cooling, hot water supply and other application scenarios. Heat pump units heat fluid media by absorbing heat from low-temperature heat sources (such as air, soil or water), thereby achieving effective energy transfer. In actual applications, since the compressor lubricating oil and refrigerant are not easily separated after mixing, the lubricating oil circulates with the refrigerant into various components of the system, which not only affects the heat exchange efficiency, but may also cause increased wear or even damage to the compressor, seriously affecting the service life and operational reliability of the heat pump unit.

[0003] In the related art, a gas-liquid separator or a specially designed oil separator can be added to reduce the amount of lubricating oil entering other system components such as the evaporator, or high-efficiency filter materials can be used to capture oil droplets. However, in actual applications, the inventors found that in an environment with low ambient temperature, although the solution of the related art achieves the separation of lubricating oil, the unit will have problems such as poor circulation of compressor lubricating oil and low oil return efficiency when operating at low load demand or low frequency. Summary of the invention

[0004] The present application provides a high-efficiency tank heat exchanger, a heat pump unit, an oil return control method and a storage medium, which solves the problems of poor circulation of compressor lubricating oil and low oil return efficiency in the unit in the related art. The present solution enables the lubricating oil to participate in the lubrication process of the compressor, helps to extend the service life of the compressor, and enables the heat pump unit to operate efficiently and reliably under low-temperature heating conditions.

[0005] In a first aspect, the present application provides a high-efficiency tank heat exchanger, which includes a liquid inlet pipe, an inner tube, a water pipe, an outer tube and an oil return pipe.

[0006] Among them, the liquid inlet pipe is used to connect the liquid refrigerant;

[0007] The inner cylinder is connected to the liquid inlet pipe so that the liquid refrigerant is introduced into the inner cylinder through the liquid inlet pipe, and a plurality of flow-averaging holes are arranged at the lower part of the inner cylinder, and the flow-averaging holes are used to guide the liquid refrigerant out of the inner cylinder;

[0008] The water pipe is wound around the outer wall of the inner cylinder, and the water pipe is used to circulate the refrigerant to perform heat exchange with the liquid refrigerant flowing out of the inner cylinder;

[0009] The inner cavity of the outer cylinder is used to accommodate the inner cylinder and the water pipe, and the upper and lower parts of the outer cylinder are respectively provided with an inlet pipe and an outlet pipe connected to the water pipe, and the upper part of the outer cylinder is also provided with an inlet and outlet pipe, which is used to guide the gaseous refrigerant generated after heat exchange from the inner cavity of the outer cylinder or to guide the gaseous refrigerant into the inner cavity of the outer cylinder;

[0010] The oil return pipe passes through the outer cylinder and the inner cylinder, and a plurality of oil return holes are provided on the side wall of the oil return pipe. The oil return holes are used to introduce lubricating oil into the oil return pipe. The first end of the oil return pipe is located in the inner cavity of the outer cylinder, and the first end of the oil return pipe is higher than the main part of the oil return pipe to connect to the gaseous refrigerant, and the second end of the oil return pipe is used to connect to external equipment.

[0011] In the second aspect, the present application also provides a heat pump unit, which includes the high-efficiency tank heat exchanger provided in the first aspect above, and also includes a compressor, a fin heat exchanger, a plate heat exchanger, a four-way valve, a filter, a main electronic expansion valve, an enthalpy-increasing electronic expansion valve, a first three-way valve, a second three-way valve and a two-way solenoid valve.

[0012] Among them, the exhaust port of the compressor is connected to the first inlet and outlet of the four-way valve, the second inlet and outlet of the four-way valve is connected to the first connection port of the finned heat exchanger, the second connection port of the finned heat exchanger is connected to the first inlet and outlet of the main electronic expansion valve through a filter, the main electronic expansion valve is connected to the first inlet and outlet of the plate heat exchanger and the first inlet and outlet of the enthalpy increasing electronic expansion valve through the first three-way valve, the second inlet and outlet of the enthalpy increasing electronic expansion valve is connected to the second inlet and outlet of the plate heat exchanger, the third inlet and outlet of the plate heat exchanger are connected to the enthalpy increasing port of the compressor and an inlet and outlet of the two-way solenoid valve through the second three-way valve, the other inlet and outlet of the two-way solenoid valve is connected to the second end of the return oil pipe, the fourth inlet and outlet of the plate heat exchanger is connected to the liquid inlet pipe of the high-efficiency tank heat exchanger, and the inlet and outlet pipes of the high-efficiency tank heat exchanger are connected to the fourth inlet and outlet of the four-way valve.

[0013] In a third aspect, the present application further provides an oil return control method, which is applied to the heat pump unit provided in the second aspect above, and the oil return control method comprises:

[0014] Acquire the operating frequency of the compressor in real time to maintain the operating frequency of the compressor at a preset oil return frequency;

[0015] When the operating frequency of the compressor is the preset oil return frequency, a first pressure value at the exhaust port of the corresponding compressor, a second pressure value at the return port of the corresponding compressor, and a cumulative operating time are obtained;

[0016] Determine whether to open the two-way solenoid valve according to the first pressure value, the second pressure value and the accumulated running time;

[0017] When the two-way solenoid valve is opened, the first pressure value, the second pressure value and the accumulated running time are re-obtained;

[0018] Whether to close the two-way solenoid valve is determined according to the latest first pressure value, the latest second pressure value, and the accumulated operating time after reset.

[0019] In a fourth aspect, the present application further provides a storage medium storing computer executable instructions, which are used to execute the oil return control method of the present application when executed by a processor.

[0020] The present application provides an oil return pipeline in the high-efficiency tank heat exchanger, so that an oil return channel can be formed between the high-efficiency tank heat exchanger and the compressor in the heat pump unit, and then controls the opening or closing of the two-way solenoid valve by detecting the change in the compressor pressure, thereby optimizing the oil return control of the heat pump unit, avoiding the problem of the compressor lubricating oil only flowing out but not entering due to factors such as the opening of the electronic expansion valve and the solubility of the lubricating oil, so that the lubricating oil can participate in the lubrication process of the compressor action, thereby extending the service life of the compressor, and allowing the heat pump unit to still operate efficiently and reliably under low-temperature heating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A cross-sectional schematic diagram of a high-efficiency tank heat exchanger provided in one embodiment of the present application;

[0022] Figure 2 A schematic diagram of the structure of a heat pump unit provided in one embodiment of the present application;

[0023] Figure 3 A schematic diagram of the steps of an oil return control method provided in one embodiment of the present application. DETAILED DESCRIPTION

[0024] The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are only used to explain the embodiments of the present application, rather than to limit the embodiments of the present application. It should also be noted that, for ease of description, only the parts related to the embodiments of the present application rather than all structures are shown in the accompanying drawings, and those skilled in the art should be able to think of it after reading the specification of this application that as long as the technical features do not contradict each other, any combination of the technical features can constitute an optional implementation method.

[0025] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable when appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally a class, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally represents that the objects associated before and after are in an "or" relationship. In the description of the present application, "multiple" means two or more, and "several" means one or more.

[0026] As energy and environmental issues become increasingly prominent, green and efficient heating methods have attracted much attention. Heat pump units heat fluid media by absorbing heat from low-temperature heat sources (such as air, soil or water), thereby achieving effective energy transfer. That is, heat pump units are highly efficient and energy-saving, and are widely used in heating, cooling, hot water supply and other application scenarios.

[0027] In actual applications, since the compressor lubricating oil and refrigerant are difficult to separate after mixing, the lubricating oil circulates with the refrigerant into various components of the system, which not only affects the heat exchange efficiency, but may also cause increased wear or even damage to the compressor, seriously affecting the service life and operational reliability of the heat pump unit.

[0028] In the related art, a gas-liquid separator or a specially designed oil separator can be added to reduce the amount of lubricating oil entering other system components such as the evaporator, or high-efficiency filter materials can be used to capture oil droplets. However, in actual applications, the inventors found that in an environment with low ambient temperature, although the solution of the related art achieves the separation of lubricating oil, the unit will have problems such as poor circulation of compressor lubricating oil and low oil return efficiency when operating at low load demand or low frequency.

[0029] After in-depth testing, the inventors found that although the solutions of the related technology can partially return the oil, they ignore the two system liquid reservoirs of the condenser and the evaporator. Especially in the scenario where the high-efficiency tank heat exchanger is used as the condenser, when the liquid refrigerant is injected into the high-efficiency tank heat exchanger from above, part of the liquid refrigerant will flash evaporate into gaseous refrigerant, and most of the liquid refrigerant will be heat exchanged inside the heat exchanger. At this time, more compressor lubricating oil will be stored at the bottom of the heat exchanger and cannot flow back to the compressor to participate in the lubrication process, which leads to problems such as poor circulation of the compressor lubricating oil and low oil return efficiency.

[0030] In this regard, the embodiment of the present application provides a high-efficiency tank heat exchanger, which can effectively reduce the deposition of lubricating oil at the bottom of the heat exchanger and send it to the compressor to realize oil return, such as Figure 1 As shown, Figure 1 This is a cross-sectional schematic diagram of a high-efficiency tank heat exchanger provided in one embodiment of the present application. The high-efficiency tank heat exchanger includes a liquid inlet pipe 101, an inner tube 102, a water pipe 103, an outer tube 104 and an oil return pipe 105.

[0031] Among them, the inner cylinder 102 is connected with the liquid inlet pipe 101, and the liquid refrigerant can be introduced into the inner cylinder 102 through the liquid inlet pipe 101. The water pipe 103 is arranged around the outer wall of the inner cylinder 102. The inner cavity of the outer cylinder 104 is used to accommodate the inner cylinder 102 and the water pipe 103, and a plurality of equal flow holes are provided at the lower part of the inner cylinder 102. The equal flow holes are used to guide the liquid refrigerant from the inside of the inner cylinder 102 to enter the inner cavity of the outer cylinder 104. In addition, the water pipe 103 is used to circulate the refrigerant to exchange heat with the liquid refrigerant flowing out of the inner cylinder 102.

[0032] In addition, the upper and lower parts of the outer cylinder 104 are respectively provided with an inlet pipe and an outlet pipe connected with the water pipe 103, and the upper part of the outer cylinder 104 is also provided with an inlet and outlet pipe, which is used to guide the gaseous refrigerant generated after heat exchange from the inner cavity of the outer cylinder 104 or to guide the gaseous refrigerant into the inner cavity of the outer cylinder 104. Moreover, the return oil pipe 105 is penetrated through the outer cylinder 104 and the inner cylinder 102, that is, the first end of the return oil pipe 105 is located in the inner cavity of the outer cylinder 104, and it also passes through the inner cylinder 102. A plurality of return oil through holes are provided on the side wall of the return oil pipe 105, and the return oil through holes are used to guide lubricating oil into the return oil pipe 105. The first end of the oil return pipe 105 is higher than the main part of the oil return pipe 105 to connect to the gaseous refrigerant, and the second end of the oil return pipe 105 is used to connect to an external device, such as a compressor. In this regard, the gaseous refrigerant can enter the compressor through the oil return pipe 105, and when it flows through the oil return hole, it can bring the lubricating oil into the oil return pipe 105 and make it flow to the compressor to achieve oil return.

[0033] Therefore, an oil return pipeline can be provided in the high-efficiency tank heat exchanger to ensure that the oil can be effectively returned to the compressor, so that the lubricating oil can participate in the lubrication process of the compressor, reducing the lubricating oil deposited at the bottom of the high-efficiency tank heat exchanger, and helping to ensure the reliability of the heat pump unit using the high-efficiency tank heat exchanger.

[0034] In one embodiment, the first end of the oil return pipe is perpendicular to the main body of the oil return pipe, and the height of the first end of the oil return pipe is greater than or equal to the first height value and less than or equal to the second height value, the first height value is one-third of the height of the outer cylinder, and the second height value is two-thirds of the height of the outer cylinder. It can be understood that within this height range, the first end of the oil return pipe can better access the gaseous refrigerant, which can avoid the situation where the oil return pipe port is too low to access the gaseous refrigerant and the situation where the oil return pipe port is too high to smoothly discharge the gaseous refrigerant, which helps to bring the lubricating oil out of the high-efficiency tank heat exchanger to participate in the oil return cycle.

[0035] In some embodiments, multiple oil return holes are arranged at intervals in the area of ​​the oil return pipe in the inner cylinder. It can be understood that the oil return pipe passes through the inner cylinder, that is, part of the oil return pipe is located inside the inner cylinder, and this part of the pipe is the area of ​​the oil return pipe in the inner cylinder. Accordingly, multiple oil return holes are arranged at intervals in the area according to preset intervals. Moreover, the position of the oil return hole is also lower than the position of the flow equalizing hole, so as to more smoothly guide the lubricating oil deposited at the bottom.

[0036] Figure 2 A structural schematic diagram of a heat pump unit provided for an embodiment of the present application is shown in the figure. In one embodiment, the heat pump unit includes the high-efficiency tank heat exchanger 240 provided in the above embodiment. In addition, the heat pump unit also includes a compressor 210, a fin heat exchanger 220, a plate heat exchanger 230, a four-way valve 211, a filter 212, a main electronic expansion valve 213, an enthalpy-increasing electronic expansion valve 214, a first three-way valve 215, a second three-way valve 216 and a two-way solenoid valve 217.

[0037] The exhaust port of the compressor 210 is connected to the first inlet and outlet of the four-way valve 211, the second inlet and outlet of the four-way valve 211 is connected to the first connection port of the finned heat exchanger 220, the second connection port of the finned heat exchanger 220 is connected to the first inlet and outlet of the main electronic expansion valve 213 through the filter 212, the main electronic expansion valve 213 is connected to the first inlet and outlet of the plate heat exchanger 230 and the first inlet and outlet of the enthalpy-increasing electronic expansion valve 214 through the first three-way valve 215, and the enthalpy-increasing electronic expansion valve The second inlet and outlet ends of 214 are connected to the second inlet and outlet of the plate heat exchanger 230, the third inlet and outlet of the plate heat exchanger 230 are respectively connected to the enthalpy increase port of the compressor 210 and an inlet and outlet of the two-way solenoid valve 217 through the second three-way valve 216, the other inlet and outlet of the two-way solenoid valve 217 is connected to the second end of the return oil pipe, the fourth inlet and outlet of the plate heat exchanger 230 is connected to the liquid inlet pipe of the high-efficiency tank heat exchanger 240, and the inlet and outlet pipes of the high-efficiency tank heat exchanger 240 are connected to the fourth inlet and outlet of the four-way valve 211.

[0038] In this regard, the high-efficiency tank heat exchanger 240 is connected to the second three-way valve 216 connected to the enthalpy increase port of the compressor 210 through the two-way solenoid valve 217 to form an oil return channel. Moreover, by controlling the opening and closing state of the two-way solenoid valve 217, the control of the conduction and closing of the oil return channel can be achieved. It can be understood that in one cycle, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 210 flows to the high-efficiency tank heat exchanger 240 through the four-way valve 211, and the gaseous refrigerant condenses and exchanges heat with the water pipe of the high-efficiency tank heat exchanger 240 from top to bottom to obtain a medium-temperature and medium-pressure gaseous refrigerant. The medium-temperature and medium-pressure gaseous refrigerant in the middle of the condensation is introduced into the bottom of the inner cylinder of the high-efficiency tank heat exchanger 240 through the return oil pipe arranged in the high-efficiency tank heat exchanger 240, and dissolves the lubricating oil deposited at the bottom of the inner cylinder of the high-efficiency tank heat exchanger 240, and then takes away the compressor 210 lubricating oil deposited at the bottom, and is transported back to the enthalpy increase port of the compressor 210 through the two-way solenoid valve 217, so that the lubricating oil can return to the compressor 210 to participate in the lubrication process of the movement.

[0039] Therefore, this solution introduces a high-efficiency tank heat exchanger into the heat pump unit, so that an oil return channel can be formed between the high-efficiency tank heat exchanger and the compressor, and through the oil return, the lubricating oil can participate in the lubrication process of the compressor, which helps to ensure the stable and reliable operation of the compressor.

[0040] Figure 3 This is a schematic diagram of the steps of the oil return control method provided in an embodiment of the present application. The method can be applied to the heat pump unit provided in the above embodiment. By controlling the two-way solenoid valve, the control of the oil return is optimized to better return the lubricating oil to the compressor. The specific steps are as follows:

[0041] Step S110: acquiring the operating frequency of the compressor in real time to maintain the operating frequency of the compressor at a preset oil return frequency.

[0042] After determining the current operating frequency of the compressor, the current operating frequency of the compressor is compared with the preset oil return frequency, and then the compressor is frequency-up or frequency-downgraded so that the operating frequency of the compressor can be maintained at the preset oil return frequency, thereby better performing oil return.

[0043] It is conceivable that in some embodiments, in addition to setting the preset oil return frequency, a corresponding operating time threshold may also be set, so that when the operating time of the compressor meets the operating time threshold and the current operating frequency is lower than the preset oil return frequency, the compressor is controlled to increase the frequency so that the compressor frequency reaches the preset oil return frequency. For example, if the compressor runs at 30HZ for 60 minutes, that is, it meets the above-mentioned corresponding operating time and operating frequency requirements, then the frequency is forced to increase so that it runs at an oil return frequency of 65HZ.

[0044] Step S120: When the operating frequency of the compressor is a preset oil return frequency, a first pressure value at the exhaust port of the corresponding compressor, a second pressure value at the return port of the corresponding compressor, and a cumulative operating time are obtained.

[0045] When the compressor is running at a preset oil return frequency, the pressure values ​​of the inlet and outlet of the compressor are obtained, that is, the first pressure value at the exhaust port of the compressor and the second pressure value at the return port of the compressor. In addition, the accumulated running time of the compressor needs to be determined. It is conceivable that the corresponding pressure values ​​can be obtained by detecting pressure sensors arranged at the exhaust port and the return port of the compressor.

[0046] Step S130: Determine whether to open the two-way solenoid valve according to the first pressure value, the second pressure value and the accumulated operating time.

[0047] It is understandable that the opening of the two-way solenoid valve is associated with the pressure value of the inlet and outlet of the compressor and the corresponding cumulative running time, so as to facilitate the control and optimization of the opening of the two-way solenoid valve. In some embodiments, after determining the first pressure value and the second pressure value, the ratio between the first pressure value and the second pressure value is calculated, and the ratio is then used as the pressure ratio. Then, it is determined whether to open the two-way solenoid valve based on the pressure ratio and the cumulative running time. If the pressure ratio is greater than or equal to the first preset ratio and the cumulative running time is greater than or equal to the first preset time, it is determined to open the two-way solenoid valve, and then the two-way solenoid valve is controlled to open. In this regard, by detecting the pressure of the compressor inlet and outlet and the cumulative running time, the two-way solenoid valve is opened in time to introduce the lubricating oil at the bottom of the inner cylinder of the high-efficiency tank heat exchanger into the compressor, which helps to extend the service life of the compressor and ensure the efficient and reliable operation of the unit.

[0048] Optionally, in one embodiment, the first preset ratio is set to 15, and the first preset time is set to 120 minutes to correspond to the low-temperature heating condition. At this time, when the pressure ratio is greater than or equal to 15 and the cumulative operating time reaches 120 minutes, the two-way solenoid valve is opened, so that the heat pump unit can still operate efficiently and reliably under low-temperature conditions.

[0049] Step S140: when the two-way solenoid valve is opened, reacquire the first pressure value, the second pressure value and reset the accumulated running time.

[0050] In response to the opening of the two-way solenoid valve, the accumulated running time is reset, that is, the timing is restarted and the time after the restart is used as the accumulated running time. In addition, due to the opening of the two-way solenoid valve, the pressure at the return port and the exhaust port of the compressor will change, and it is necessary to re-acquire the first pressure value and the second pressure value.

[0051] Step S150: Determine whether to close the two-way solenoid valve according to the latest first pressure value, the latest second pressure value, and the accumulated operating time after reset.

[0052] Similarly, the closing of the two-way solenoid valve is associated with the pressure value of the inlet and outlet of the compressor and the corresponding accumulated running time, but it is worth noting that the associated accumulated running time is updated, that is, the timing of the accumulated running time is restarted after the two-way solenoid valve is opened, so as to control whether the two-way solenoid valve is closed. For example, in some embodiments, when the pressure ratio corresponding to the first pressure value and the second pressure value is less than or equal to the second preset ratio or the accumulated running time after reset reaches the second preset time, it is determined to close the two-way solenoid valve.

[0053] Optionally, in one embodiment, the second preset time is less than the first preset time, such as the second preset time is set to 20 minutes, and the second preset ratio is also less than the first preset ratio, such as the second preset ratio is set to 10. In this regard, when the pressure ratio is less than 10 or the cumulative running time reaches 20 minutes, the two-way solenoid valve is closed.

[0054] It can be seen that this scheme optimizes the oil return control of the heat pump unit by detecting the change in compressor pressure to control the opening or closing of the two-way solenoid valve, avoids the problem of compressor lubricating oil only flowing out but not in due to factors such as the opening of the electronic expansion valve and the solubility of the lubricating oil, extends the service life of the compressor, and enables the heat pump unit to operate efficiently and reliably under low-temperature heating conditions.

[0055] In some embodiments, the control of the two-way solenoid valve may also be performed by determining the valve state of the two-way solenoid valve according to the exhaust temperature. It is conceivable that the compressor may be detected by a temperature sensor to obtain the exhaust temperature. Furthermore, when the exhaust temperature is greater than or equal to the first temperature value and the accumulated running time is greater than or equal to the first preset time, it is determined to open the two-way solenoid valve to control the opening of the two-way solenoid valve. It is conceivable that the exhaust temperature of the compressor may change, and the exhaust temperature of the compressor needs to be obtained in real time.

[0056] Similarly, after the two-way solenoid valve is opened, the timing of the accumulated running time needs to be restarted accordingly to determine whether to close the two-way solenoid valve according to the latest exhaust temperature and the accumulated running time after reset. Optionally, in one embodiment, when the latest exhaust temperature is less than the second temperature value or the accumulated running time after reset reaches the second preset time, it is determined to close the two-way solenoid valve to control the two-way solenoid valve to close, thereby achieving control of the two-way solenoid valve to adapt to the exhaust temperature change of the compressor, thereby better performing oil return control, and helping to ensure the stable operation of the compressor.

[0057] For example, in one embodiment, the first temperature value is set to 100°C, the second temperature value is set to 80°C; the first preset time is set to 100 minutes, and the second preset time is set to 80 minutes. By detecting the exhaust temperature, when the exhaust temperature is greater than or equal to 100°C and the cumulative running time reaches 120 minutes, the two-way solenoid valve is opened; when the exhaust temperature is less than 80°C or the cumulative running time after reset reaches 20 minutes, the two-way solenoid valve is closed.

[0058] An embodiment of the present application also provides a storage medium storing computer executable instructions, which, when executed by a processor, are used to perform relevant operations in the oil return control method provided in any embodiment of the present application.

[0059] Computer-readable storage media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0060] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0061] Note that the above are only preferred embodiments of the present application and the technical principles used. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present application. Therefore, although the present application is described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A high efficiency tank heat exchanger, characterized in that: include: A liquid inlet pipe, the liquid inlet pipe is used to connect to the liquid refrigerant; An inner cylinder, the inner cylinder is connected to the liquid inlet pipe so as to introduce the liquid refrigerant into the inner cylinder through the liquid inlet pipe, and a plurality of flow-balancing holes are provided at the lower part of the inner cylinder, and the flow-balancing holes are used to guide the liquid refrigerant out of the inner cylinder; A water pipe, the water pipe is wound around the outer wall of the inner cylinder, and the water pipe is used to circulate refrigerant to perform heat exchange with the liquid refrigerant flowing out of the inner cylinder; An outer cylinder, the inner cavity of the outer cylinder is used to accommodate the inner cylinder and the water pipe, and the upper and lower parts of the outer cylinder are respectively provided with an inlet pipe and an outlet pipe connected with the water pipe, and the upper part of the outer cylinder is also provided with an inlet and outlet pipe, and the inlet and outlet pipes are used to guide the gaseous refrigerant generated after heat exchange from the inner cavity of the outer cylinder or to guide the gaseous refrigerant into the inner cavity of the outer cylinder; An oil return pipe is provided through the outer cylinder and the inner cylinder, and a plurality of oil return holes are provided on the side wall of the oil return pipe. The oil return holes are used to introduce lubricating oil into the oil return pipe. The first end of the oil return pipe is located in the inner cavity of the outer cylinder, and the first end of the oil return pipe is higher than the main body of the oil return pipe to connect to the gaseous refrigerant, and the second end of the oil return pipe is used to connect to external equipment.

2. The high-efficiency tank heat exchanger according to claim 1, characterized in that: The first end of the oil return pipe is perpendicular to the main part of the oil return pipe, and the height of the first end of the oil return pipe is greater than or equal to a first height value and less than or equal to a second height value, the first height value is one third of the height of the outer cylinder, and the second height value is two thirds of the height of the outer cylinder.

3. The high-efficiency tank heat exchanger according to claim 1 or 2, characterized in that: A plurality of the oil return through holes are arranged at intervals on the oil return pipe in the area of ​​the inner cylinder, and the positions of the oil return through holes are lower than the positions of the flow balancing holes.

4. A heat pump unit, characterized in that: The heat pump unit comprises a high-efficiency tank heat exchanger as described in any one of claims 1 to 3, wherein the heat pump unit further comprises a compressor, a fin heat exchanger, a plate heat exchanger, a four-way valve, a filter, a main electronic expansion valve, an enthalpy-increasing electronic expansion valve, a first three-way valve, a second three-way valve and a two-way solenoid valve; Among them, the exhaust port of the compressor is connected to the first inlet and outlet of the four-way valve, the second inlet and outlet of the four-way valve is connected to the first connecting port of the finned heat exchanger, the second connecting port of the finned heat exchanger is connected to the first inlet and outlet of the main electronic expansion valve through the filter, the main electronic expansion valve is respectively connected to the first inlet and outlet of the plate heat exchanger and the first inlet and outlet of the enthalpy increasing electronic expansion valve through the first three-way valve, the second inlet and outlet of the enthalpy increasing electronic expansion valve is connected to the second inlet and outlet of the plate heat exchanger, the third inlet and outlet of the plate heat exchanger is respectively connected to the enthalpy increasing port of the compressor and an inlet and outlet of the two-way solenoid valve through the second three-way valve, the other inlet and outlet of the two-way solenoid valve is connected to the second end of the return oil pipe, the fourth inlet and outlet of the plate heat exchanger is connected to the liquid inlet pipe of the high-efficiency tank heat exchanger, and the inlet and outlet pipes of the high-efficiency tank heat exchanger are connected to the fourth inlet and outlet of the four-way valve.

5. An oil return control method, characterized in that: Applied to the heat pump unit according to claim 4, the oil return control method comprises: Acquiring the operating frequency of the compressor in real time to maintain the operating frequency of the compressor at a preset oil return frequency; When the operating frequency of the compressor is the preset oil return frequency, obtaining a first pressure value at the exhaust port of the compressor, a second pressure value at the return port of the compressor, and a cumulative operating time; determining whether to open the two-way solenoid valve according to the first pressure value, the second pressure value and the accumulated running time; When the two-way solenoid valve is opened, reacquiring the first pressure value, the second pressure value and resetting the accumulated running time; Whether to close the two-way solenoid valve is determined according to the latest first pressure value, the latest second pressure value, and the accumulated operating time after reset.

6. The oil return control method according to claim 5, characterized in that: The determining whether to open the two-way solenoid valve according to the first pressure value, the second pressure value and the accumulated running time includes: determining a ratio of the first pressure value to the second pressure value as a pressure ratio; When the pressure ratio is greater than or equal to a first preset ratio and the accumulated running time is greater than or equal to a first preset time, it is determined to open the two-way solenoid valve to control the two-way solenoid valve to open.

7. The oil return control method according to claim 5 or 6, characterized in that: The determining whether to close the two-way solenoid valve according to the latest first pressure value, the latest second pressure value and the accumulated running time after reset includes: Determine, according to the latest first pressure value and the latest second pressure value, a ratio of the first pressure value to the second pressure value as an updated pressure ratio; When the updated pressure ratio is less than the second preset ratio or the accumulated running time after reset reaches the second preset time, it is determined to close the two-way solenoid valve to control the two-way solenoid valve to close.

8. The oil return control method according to claim 5 or 6, characterized in that: The method further comprises: Acquire the exhaust temperature in real time, and when the exhaust temperature is greater than or equal to a first temperature value and the accumulated operating time is greater than or equal to a first preset time, determine to open the two-way solenoid valve to control the two-way solenoid valve to open; Whether to close the two-way solenoid valve is determined according to the latest exhaust temperature and the accumulated operating time after reset.

9. The oil return control method according to claim 8, characterized in that: The step of determining whether to close the two-way solenoid valve according to the latest exhaust temperature and the accumulated operating time after reset includes: When the latest exhaust temperature is less than the second temperature value or the accumulated operating time after reset reaches the second preset time, it is determined to close the two-way solenoid valve to control the two-way solenoid valve to be closed.

10. A storage medium storing computer executable instructions, characterized in that: When the computer executable instructions are executed by a processor, they are used to perform the oil return control method according to any one of claims 5 to 9.

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