Air source heat pump unit and air source heat pump unit control method

Abstract

The present application relates to an air source heat pump unit and an air source heat pump unit control method, the unit comprising a compressor, a four-way valve, an indoor heat exchanger, a first expansion valve, an outdoor heat exchanger, a flow guide assembly, a controller, an exhaust temperature sensor, a water inlet temperature sensor and an ambient temperature sensor; the compressor, the four-way valve, the indoor heat exchanger, the first expansion valve and the outdoor heat exchanger are connected to form a refrigerant circulation system; the flow guide assembly comprises a flow guide pipe group and a control valve arranged on the flow guide pipe group, and the two ends of the flow guide pipe group are connected with a gas collecting pipe interface of the outdoor heat exchanger and a refrigerant pipe group of the indoor heat exchanger respectively; the controller is electrically connected with the compressor, the four-way valve, the outdoor heat exchanger, the first expansion valve, the control valve, the exhaust temperature sensor, the water inlet temperature sensor and the ambient temperature sensor respectively. The unit and the control method can solve the problems of liquid entrainment in the compressor suction, low exhaust temperature and low system energy efficiency caused by refrigerant deposition when starting after debugging or long-term storage.

Description

Technical Field

[0001] This invention relates to the field of heat pump equipment technology, and in particular to an air source heat pump unit and an air source heat pump unit control method. Background Technology

[0002] For heat pump units that have been stored for a long time or are in the installation and commissioning stage, directly turning on the heating mode when the ambient temperature and the inlet water temperature are similar may easily cause the following problems:

[0003] 1. Due to the small temperature difference, the finned heat exchanger (as an evaporator) has insufficient heat exchange power with the outside world, and the refrigerant cannot fully absorb heat and evaporate. A large amount of liquid refrigerant tends to remain at the bottom of the coil, forming refrigerant deposits. 2. Deposited liquid refrigerant may enter the compressor through the circulation, causing "wet compression," which leads to a significant decrease in exhaust temperature, increases compressor wear, and shortens its service life; 3. After liquid refrigerant enters the compressor, it not only cannot effectively participate in heat exchange, but also occupies the effective circulation volume of the system, resulting in a decrease in the unit's heating capacity and energy efficiency, which affects commissioning efficiency and operating economy.

[0004] Currently common methods such as "preheating and letting it stand" and "gradual load increase" can only alleviate the problem, but cannot fundamentally solve the problems of refrigerant deposition causing liquid carryover in compressor intake, low exhaust temperature, and reduced system energy efficiency under such operating conditions. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide an air source heat pump unit that solves the problems of compressor suction liquid, low exhaust temperature and low system energy efficiency caused by refrigerant deposition in the finned heat exchanger when starting up the heat pump unit after commissioning or long-term storage.

[0006] This invention is achieved through the following technical solution: an air source heat pump unit, comprising a compressor, a four-way valve, an indoor heat exchanger, a first expansion valve, an outdoor heat exchanger, a flow guiding assembly, a controller, an exhaust temperature sensor for detecting the exhaust temperature of the compressor, an inlet water temperature sensor for detecting the inlet water temperature of the indoor heat exchanger, and an ambient temperature sensor for detecting the outdoor ambient temperature; the compressor, four-way valve, indoor heat exchanger, first expansion valve, and outdoor heat exchanger are connected to form a refrigerant circulation system; the flow guiding assembly includes a flow guiding pipe assembly and a control valve disposed on the flow guiding pipe assembly, one end of the flow guiding pipe assembly being connected to the gas collecting pipe interface of the outdoor heat exchanger, and the other end being connected to the refrigerant pipe assembly of the indoor heat exchanger; The controller is electrically connected to the compressor, four-way valve, outdoor heat exchanger, first expansion valve, control valve, exhaust temperature sensor, inlet water temperature sensor and ambient temperature sensor respectively, and is used to open the control valve according to the difference between the inlet water temperature and the outdoor ambient temperature and the exhaust temperature when the heating mode is turned on.

[0007] Compared with the prior art, the air source heat pump unit provided by the present invention automatically opens the flow guide according to the difference between the inlet water temperature and the outdoor ambient temperature and the compressor exhaust temperature through the flow guide component and controller. This guides the deposited liquid refrigerant in the outdoor heat exchanger to the refrigerant pipe group in the indoor heat exchanger, so that the deposited liquid refrigerant re-enters the main circuit for refrigerant circulation. This solves the problems of compressor suction liquid, low exhaust temperature and low system energy efficiency caused by refrigerant deposit in the finned heat exchanger when the heat pump unit is started after commissioning or long-term storage.

[0008] In one embodiment, the air source heat pump unit further includes a superheat sensor for detecting the superheat of the compressor return gas. The superheat sensor is electrically connected to the controller, which is also used to adjust the opening of the control valve based on the return gas superheat and the exhaust temperature. The flow rate of the deposited refrigerant is dynamically adjusted according to the compressor's return gas superheat and exhaust temperature to ensure the stability of the refrigerant circulation system.

[0009] In one embodiment, the indoor heat exchanger is a high-efficiency tank heat exchanger, which has a first interface for connecting to the outdoor heat exchanger and a second interface for connecting to the four-way valve. The high-efficiency tank heat exchanger contains a liquid storage tank, one end of which is connected to the first interface, and the other end is connected to the second interface via the refrigerant piping assembly. The guide pipe assembly is connected to the liquid storage tank. The liquid storage tank effectively prevents excessive refrigerant accumulation in the indoor heat exchanger, avoiding ineffective occupation of the heat transfer area. Simultaneously, it regulates refrigerant circulation. When the load on the outdoor heat exchanger (which is an evaporator in heating mode) increases, the liquid storage tank releases the stored liquid refrigerant to replenish the system, ensuring sufficient refrigerant supply. When the load decreases, excess liquid refrigerant is stored in the liquid storage tank, ensuring the system always operates stably under optimal conditions.

[0010] In one embodiment, the air source heat pump unit further includes an economizer and a three-way valve. The economizer includes a first heat exchange tube group and a second heat exchange tube group for heat exchange. One end of the first heat exchange tube group is connected to the first interface, and the other end is connected to the first connector of the three-way valve. The liquid distribution pipe interface of the outdoor heat exchanger is connected to the second connector of the three-way valve through the first expansion valve. The compressor is provided with a gas injection port. One end of the second heat exchange tube group is connected to the gas injection port, and the other end is connected to the third connector of the three-way valve. Thus, a portion of the refrigerant in the main circuit is led to the economizer through the three-way valve to exchange heat with the refrigerant in the main circuit. The resulting medium-pressure gaseous refrigerant is injected into the compressor as enthalpy-increasing gas injection. At the same time, the refrigerant in the main circuit is subcooled in the economizer.

[0011] In one embodiment, the air source heat pump unit further includes a second expansion valve electrically connected to the controller, and the second heat exchange tube assembly is connected to the third connector of the three-way valve via the second expansion valve. The second expansion valve throttles and reduces the pressure of the refrigerant drawn from the main circuit, creating conditions for a phase change.

[0012] In one embodiment, the air source heat pump unit further includes a filter, and the liquid distribution pipe interface of the outdoor heat exchanger is connected in sequence to the second connector of the three-way valve through the filter and the first expansion valve. The filter removes impurities from the system, protecting the compressor.

[0013] The present invention also provides a control method for an air source heat pump unit, used in the air source heat pump unit described above, the method comprising: When the heating mode is turned on, the compressor is controlled to start running at a preset first time. At the same time, the current outdoor ambient temperature, the current inlet water temperature of the indoor heat exchanger, and the current exhaust temperature of the compressor are acquired. If the difference between the current inlet water temperature and the current outdoor ambient temperature is less than a preset first temperature threshold, and the current exhaust temperature is less than a preset second temperature threshold, the control valve is controlled to open to a preset first opening degree; otherwise, the air source heat pump unit is controlled to operate in a preset heating mode.

[0014] In one embodiment, the method further includes the following steps: after controlling the control valve to open to a preset first opening degree, obtaining the return gas superheat of the compressor; if the current return gas superheat degree is less than a preset first threshold and the current exhaust temperature is less than a preset third temperature threshold, controlling the control valve to gradually reduce the opening degree according to a preset first proportion. Until the current return gas superheat is greater than or equal to a preset first threshold and less than or equal to a preset second threshold, and the current exhaust temperature is greater than or equal to a preset third temperature threshold and less than or equal to a preset fourth temperature threshold, the control valve is controlled to operate at the current opening for a preset second time and then closed, and the air source heat pump unit is controlled to operate in a preset heating mode.

[0015] In one embodiment, the method further includes the following steps: after controlling the control valve to open to a preset first opening degree, obtaining the return gas superheat of the compressor; if the current return gas superheat degree is greater than a preset second threshold and the current exhaust temperature is greater than a preset fourth temperature threshold, controlling the control valve to gradually increase the opening degree by a preset second proportional opening degree. Until the current return gas superheat is greater than or equal to a preset first threshold and less than or equal to a preset second threshold, and the current exhaust temperature is greater than or equal to a preset third temperature threshold and less than or equal to a preset fourth temperature threshold, the control valve is controlled to operate at the current opening for a preset second time and then closed, and the air source heat pump unit is controlled to operate in a preset heating mode.

[0016] In one embodiment, before controlling the compressor to start operation at a preset first time, and simultaneously acquiring the current outdoor ambient temperature, the current outlet water temperature of the indoor heat exchanger, and the current discharge temperature of the compressor, the following steps are included: The outlet valve of the indoor heat exchanger is closed. The fan of the outdoor heat exchanger is controlled to run at a preset speed for a preset third time.

[0017] It promotes the initial flow of refrigerant in the outdoor heat exchanger, facilitating the subsequent flow of deposited refrigerant.

[0018] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the air source heat pump unit described in Embodiment 1; Figure 2 This is a flowchart of the air source heat pump unit control method described in Example 1.

[0020] Reference numerals: 10, compressor; 20, four-way valve; 30, outdoor heat exchanger; 40, indoor heat exchanger; 50, flow guide assembly; 51, flow guide pipe assembly; 52, control valve; 60, economizer; 70, three-way valve; 80, first expansion valve; 90, second expansion valve; 100, filter. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] Example 1 like Figure 1 As shown, this embodiment provides an air source heat pump unit, including a compressor 10, a four-way valve 20, an indoor heat exchanger 40, a first expansion valve 80, an outdoor heat exchanger 30, a flow guide assembly 50, a controller (not shown), an exhaust temperature sensor (not shown) for detecting the exhaust temperature of the compressor 10, an inlet water temperature sensor (not shown) for detecting the inlet water temperature of the indoor heat exchanger 40, and an ambient temperature sensor (not shown) for detecting the outdoor ambient temperature; the compressor 10, the four-way valve 20, the indoor heat exchanger 40, the first expansion valve 80, and the outdoor heat exchanger 30 are connected to form a refrigerant circulation system. The system includes a flow guiding assembly 50 comprising a flow guiding pipe group 51 and a control valve 52 disposed on the flow guiding pipe group 51. One end of the flow guiding pipe group 51 is connected to the gas collection pipe interface of the outdoor heat exchanger 30, and the other end is connected to the refrigerant pipe group of the indoor heat exchanger 40. The controller is electrically connected to the compressor 10, the four-way valve 20, the outdoor heat exchanger 30, the first expansion valve 80, the control valve 52, the exhaust temperature sensor, the inlet water temperature sensor, and the ambient temperature sensor, respectively. When the heating mode is activated, the controller opens the control valve 52 based on the difference between the inlet water temperature and the outdoor ambient temperature, as well as the exhaust temperature. The outdoor heat exchanger 30 is a finned heat exchanger. Therefore, through the flow guiding component 50 and the controller, based on the difference between the inlet water temperature and the outdoor ambient temperature and the exhaust temperature of the compressor 10, the control valve 52 is automatically opened. Utilizing the pressure difference between the outdoor heat exchanger 30 and the indoor heat exchanger 40, the deposited liquid refrigerant in the outdoor heat exchanger 30 is guided to the refrigerant pipe group in the indoor heat exchanger 40, allowing the deposited liquid refrigerant to re-enter the main circuit for refrigerant circulation. This solves the problems of liquid carryover in the compressor 10, low exhaust temperature, and low system energy efficiency caused by refrigerant deposits in the finned heat exchanger when starting the heat pump unit after commissioning or long-term storage.

[0023] Furthermore, the control valve 52 is a proportional valve. The air source heat pump unit also includes a superheat sensor (not shown) for detecting the return superheat of the compressor 10. The superheat sensor is electrically connected to the controller, which is also used to adjust the opening of the control valve 52 based on the return superheat and the exhaust temperature. The flow rate of the deposited refrigerant is dynamically adjusted according to the return superheat and exhaust temperature of the compressor 10 to ensure the stability of the refrigerant circulation system.

[0024] In one embodiment, the indoor heat exchanger 40 is a high-efficiency tank heat exchanger, which has a first interface for connecting to the outdoor heat exchanger 30 and a second interface for connecting to the four-way valve 20. The high-efficiency tank heat exchanger contains a liquid storage tank, one end of which is connected to the first interface, and the other end is connected to the second interface via the refrigerant piping assembly. The guide pipe assembly 51 is connected to the liquid storage tank. The liquid storage tank effectively prevents excessive refrigerant accumulation in the indoor heat exchanger 40, avoiding ineffective occupation of the heat transfer area of ​​the indoor heat exchanger 40. Simultaneously, it regulates refrigerant circulation. When the load on the outdoor heat exchanger 30 (which is an evaporator in heating mode) increases, the liquid storage tank releases the stored liquid refrigerant to replenish the system, ensuring sufficient refrigerant supply. When the load decreases, excess liquid refrigerant is stored in the liquid storage tank, ensuring the system always operates stably under optimal conditions. Of course, in other alternative embodiments, the indoor heat exchanger 40 can be a plate heat exchanger.

[0025] In one embodiment, the air source heat pump unit further includes an economizer 60 and a three-way valve 70. The economizer 60 includes a first heat exchange tube group and a second heat exchange tube group for heat exchange. One end of the first heat exchange tube group is connected to the first interface, and the other end is connected to the first connector of the three-way valve 70. The liquid distribution pipe interface of the outdoor heat exchanger 30 is connected to the second connector of the three-way valve 70 through the first expansion valve 80. The compressor 10 is provided with a gas injection port. One end of the second heat exchange tube group is connected to the gas injection port, and the other end is connected to the third connector of the three-way valve 70. Thus, a portion of the refrigerant in the main circuit is led to the economizer 60 through the three-way valve 70 to exchange heat with the refrigerant in the main circuit. The resulting medium-pressure gaseous refrigerant is injected into the compressor 10 as enthalpy-increasing gas injection. At the same time, the refrigerant in the main circuit is subcooled in the economizer 60.

[0026] In one embodiment, the air source heat pump unit further includes a second expansion valve 90 electrically connected to the controller. The second heat exchange tube assembly is connected to the third connector of the three-way valve 70 via the second expansion valve 90. The second expansion valve 90 throttles and reduces the pressure of the refrigerant drawn from the main circuit, creating conditions for a phase change.

[0027] In one embodiment, the air source heat pump unit further includes a filter 100, and the liquid distribution pipe interface of the outdoor heat exchanger 40 is connected to the second connector of the three-way valve 70 in sequence through the filter 100 and the first expansion valve 80. The filter 100 removes impurities from the system, protecting the compressor 10.

[0028] Compared with the prior art, the air source heat pump unit provided by the present invention automatically opens the flow guide according to the difference between the inlet water temperature and the outdoor ambient temperature and the exhaust temperature of the compressor 10 through the flow guide component 50 and the controller. This guides the deposited liquid refrigerant in the outdoor heat exchanger 30 to the refrigerant pipe group in the indoor heat exchanger 40, so that the deposited liquid refrigerant re-enters the main circuit for refrigerant circulation. This solves the problems of liquid in the compressor 10 intake, low exhaust temperature and low system energy efficiency caused by refrigerant deposit in the finned heat exchanger when the heat pump unit is started after commissioning or long-term storage.

[0029] Example 2 like Figure 2 As shown, this embodiment provides a control method for an air source heat pump unit, used in the air source heat pump unit described in Embodiment 1. The method includes: S1: When the heating mode is turned on, the compressor is controlled to start running at a preset first time. At the same time, the current outdoor ambient temperature, the current inlet water temperature of the indoor heat exchanger, and the current exhaust temperature of the compressor are obtained.

[0030] The preset first time ranges from 0 to 3 minutes, excluding the left endpoint but including the right endpoint; that is, excluding 0 minutes but including 3 minutes. The compressor is controlled to start running for the preset first time to preheat the entire heat pump unit.

[0031] S2: If the difference between the current inlet water temperature and the current outdoor ambient temperature is less than a preset first temperature threshold, and the current exhaust temperature is less than a preset second temperature threshold, control the control valve to open to a preset first opening degree; otherwise, control the air source heat pump unit to operate in a preset heating mode.

[0032] The preset first temperature threshold ranges from 0 to 5℃, including the endpoints, i.e., 0℃ and 5℃. The preset second temperature threshold is 40℃ (other values ​​can also be set according to actual needs). The preset heating mode is the standard heating mode. The preset first opening degree is determined based on the outlet water temperature, as shown in the table below.

[0033]

[0034] By guiding the deposited liquid refrigerant from the outdoor heat exchanger to the refrigerant pipe assembly of the indoor heat exchanger, the deposited liquid refrigerant can re-enter the main circuit for refrigerant circulation, thus solving the problems of liquid carryover in compressor suction, low exhaust temperature, and low system energy efficiency caused by refrigerant deposits in the finned heat exchanger when starting up a heat pump unit after commissioning or long-term storage.

[0035] In one embodiment, after the control valve is opened to a preset first opening degree, the return gas superheat of the compressor is obtained. If the current return gas superheat degree is less than a preset first threshold and the current exhaust temperature is less than a preset third temperature threshold, the control valve is controlled to gradually reduce its opening degree according to a preset first proportion.

[0036] The first threshold is 3℃ (other values ​​can also be set according to actual conditions). The third temperature threshold is 60℃ (other values ​​can also be set according to actual conditions). The preset first proportional opening range is 10% / cycle to 15% / cycle. When the return gas superheat is <3℃ (low return gas superheat, liquid refrigerant is present) and the exhaust temperature is <60℃ (low exhaust temperature, compressor may carry liquid), the control valve opening is gradually reduced to reduce the flow rate of deposited refrigerant.

[0037] Until the current return gas superheat is greater than or equal to a preset first threshold and less than or equal to a preset second threshold, and the current exhaust temperature is greater than or equal to a preset third temperature threshold and less than or equal to a preset fourth temperature threshold, the control valve is controlled to operate at the current opening for a preset second time and then closed, and the air source heat pump unit is controlled to operate in a preset heating mode.

[0038] The second threshold is 8℃ (other values ​​can also be set according to actual conditions). The fourth temperature threshold is 90℃ (other values ​​can also be set according to actual conditions). The preset second time is 15 minutes (other values ​​can also be set according to actual conditions). 3℃≤return gas superheat≤8℃ (return gas superheat is normal) and 60℃≤exhaust temperature≤90℃ (exhaust temperature is normal): Control the control valve to operate at the current opening to ensure stable refrigerant return. After running for 15 minutes, close the control valve to ensure all deposited refrigerant is discharged, and then control the air source heat pump unit to operate in the preset heating mode.

[0039] In one embodiment, after controlling the control valve to open to a preset first opening degree, the return gas superheat of the compressor is obtained.

[0040] If the current return gas superheat is greater than a preset second threshold and the current exhaust temperature is greater than a preset fourth temperature threshold, the control valve is controlled to gradually increase its opening by a preset second proportional opening.

[0041] The preset second proportional opening value ranges from 5% / cycle to 10% / cycle. The return gas superheat is >8℃ (high return gas superheat, excessive refrigerant evaporation) and the exhaust temperature is >90℃ (high exhaust temperature, excessive system load). The control valve opening is increased to increase the flow velocity of the deposited refrigerant and replenish the refrigerant circulation volume in the system.

[0042] Until the current return gas superheat is greater than or equal to a preset first threshold and less than or equal to a preset second threshold, and the current exhaust temperature is greater than or equal to a preset third temperature threshold and less than or equal to a preset fourth temperature threshold, the control valve is controlled to operate at the current opening for a preset second time and then closed, and the air source heat pump unit is controlled to operate in a preset heating mode.

[0043] In one embodiment, before controlling the compressor to start operation at a preset first time, and simultaneously acquiring the current outdoor ambient temperature, the current outlet water temperature of the indoor heat exchanger, and the current discharge temperature of the compressor, the following steps are included: The outlet valve of the indoor heat exchanger is closed.

[0044] The fan of the outdoor heat exchanger is controlled to run at a preset speed for a preset third time.

[0045] The preset rotational speed is 50% to 60% of the rated speed. The preset third time is 5 to 10 minutes. This promotes the initial flow of refrigerant in the outdoor heat exchanger, facilitating the subsequent flow of deposited refrigerant.

[0046] Compared with the prior art, the air source heat pump unit control method provided in this embodiment guides the deposited liquid refrigerant in the outdoor heat exchanger to the refrigerant pipe group in the indoor heat exchanger, so that the deposited liquid refrigerant re-enters the main circuit for refrigerant circulation. This solves the problems of compressor suction liquid, low exhaust temperature and low system energy efficiency caused by refrigerant deposit in the finned heat exchanger when the heat pump unit is started after commissioning or long-term storage.

[0047] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments and claims of this application are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that, unless otherwise stated, “a plurality” refers to two or more; the terms “first,” “second,” “third,” etc., are used only to distinguish and not to describe a particular order or sequence, nor should they be construed as indicating or implying relative importance. The term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items. When the above description relates to drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of this application, those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0048] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An air source heat pump unit, characterized in that, The system includes a compressor, a four-way valve, an indoor heat exchanger, a first expansion valve, an outdoor heat exchanger, a flow guiding assembly, a controller, an exhaust temperature sensor for detecting the exhaust temperature of the compressor, an inlet water temperature sensor for detecting the inlet water temperature of the indoor heat exchanger, and an ambient temperature sensor for detecting the outdoor ambient temperature. The compressor, four-way valve, indoor heat exchanger, first expansion valve, and outdoor heat exchanger are connected to form a refrigerant circulation system. The flow guiding assembly includes a flow guiding pipe group and a control valve disposed on the flow guiding pipe group. One end of the flow guiding pipe group is connected to the gas collection pipe interface of the outdoor heat exchanger, and the other end is connected to the refrigerant pipe group of the indoor heat exchanger. The controller is electrically connected to the compressor, four-way valve, outdoor heat exchanger, first expansion valve, control valve, exhaust temperature sensor, inlet water temperature sensor and ambient temperature sensor respectively, and is used to open the control valve according to the difference between the inlet water temperature and the outdoor ambient temperature and the exhaust temperature when the heating mode is turned on.

2. The air source heat pump unit according to claim 1, characterized in that, The air source heat pump unit also includes a superheat sensor for detecting the superheat of the compressor return gas. The superheat sensor is electrically connected to the controller, and the controller is also used to adjust the opening of the control valve according to the superheat of the return gas and the exhaust temperature.

3. The air source heat pump unit according to claim 2, characterized in that, The indoor heat exchanger is a high-efficiency tank heat exchanger, which has a first interface for connecting to the outdoor heat exchanger and a second interface for connecting to the four-way valve; the high-efficiency tank heat exchanger has a liquid storage tank, one end of which is connected to the first interface, and the other end is connected to the second interface through the refrigerant pipe assembly, and the guide pipe assembly is connected to the liquid storage tank.

4. The air source heat pump unit according to claim 3, characterized in that, The air source heat pump unit also includes an economizer and a three-way valve; the economizer includes a first heat exchange tube group and a second heat exchange tube group for heat exchange, one end of the first heat exchange tube group is connected to the first interface, and the other end is connected to the first connector of the three-way valve, the liquid distribution pipe interface of the outdoor heat exchanger is connected to the second connector of the three-way valve through the first expansion valve; the compressor is provided with a gas injection port, one end of the second heat exchange tube group is connected to the gas injection port, and the other end is connected to the third connector of the three-way valve.

5. The air source heat pump unit according to claim 4, characterized in that, The air source heat pump unit also includes a second expansion valve electrically connected to the controller, and the second heat exchange tube group is connected to the third connector of the three-way valve through the second expansion valve.

6. The air source heat pump unit according to claim 4, characterized in that, The air source heat pump unit also includes a filter, and the liquid distribution pipe interface of the outdoor heat exchanger is connected to the second connector of the three-way valve in sequence through the filter and the first expansion valve.

7. A control method for an air source heat pump unit, used in any one of claims 1-6, characterized in that, The method includes: When the heating mode is turned on, the compressor is controlled to start running at a preset first time. At the same time, the current outdoor ambient temperature, the current inlet water temperature of the indoor heat exchanger, and the current exhaust temperature of the compressor are acquired. If the difference between the current inlet water temperature and the current outdoor ambient temperature is less than a preset first temperature threshold, and the current exhaust temperature is less than a preset second temperature threshold, the control valve is controlled to open to a preset first opening degree; otherwise, the air source heat pump unit is controlled to operate in a preset heating mode.

8. The method according to claim 7, characterized in that, The method further includes the following steps: after controlling the control valve to open to a preset first opening degree, the return gas superheat of the compressor is obtained; if the current return gas superheat degree is less than a preset first threshold and the current exhaust temperature is less than a preset third temperature threshold, the control valve is controlled to gradually reduce the opening degree according to a preset first proportion. Until the current return gas superheat is greater than or equal to a preset first threshold and less than or equal to a preset second threshold, and the current exhaust temperature is greater than or equal to a preset third temperature threshold and less than or equal to a preset fourth temperature threshold, the control valve is controlled to operate at the current opening for a preset second time and then closed, and the air source heat pump unit is controlled to operate in a preset heating mode.

9. The method according to claim 7, characterized in that, The method further includes the following steps: after controlling the control valve to open to a preset first opening degree, the return gas superheat of the compressor is obtained; if the current return gas superheat degree is greater than a preset second threshold and the current exhaust temperature is greater than a preset fourth temperature threshold, the control valve is controlled to gradually increase the opening degree by a preset second proportion. Until the current return gas superheat is greater than or equal to a preset first threshold and less than or equal to a preset second threshold, and the current exhaust temperature is greater than or equal to a preset third temperature threshold and less than or equal to a preset fourth temperature threshold, the control valve is controlled to operate at the current opening for a preset second time and then closed, and the air source heat pump unit is controlled to operate in a preset heating mode.

10. The method according to claim 7, characterized in that, Before controlling the compressor to start operation at a preset first time, and simultaneously acquiring the current outdoor ambient temperature, the current outlet water temperature of the indoor heat exchanger, and the current discharge temperature of the compressor, the following steps are included: The outlet valve of the indoor heat exchanger is closed. The fan of the outdoor heat exchanger is controlled to run at a preset speed for a preset third time.

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