Heat pump system and control method thereof

Abstract

The invention relates to a heat pump system and a control method thereof, the heat pump system is provided with a liquid spraying enthalpy increasing branch, a refrigerant in a refrigerant circulation loop can be shunted between a first throttling element and a main path of an economizer, and the refrigerant flows into an air supplementing opening of a compressor through an auxiliary path of the economizer for air supplementing and enthalpy increasing. An air supply throttling element is arranged on the liquid spraying enthalpy increasing branch, and the controller obtains the exhaust superheat degree according to the exhaust temperature and the exhaust pressure, determines the optional adjusting mode of the opening degree of the air supply throttling element according to the exhaust superheat degree and obtains the superheat degree of the economizer according to the side road inlet temperature and the side road outlet temperature. According to the method, the target adjusting mode is determined from the selectable adjusting modes based on the superheat degree of the economizer, the opening degree of the air supply throttling element is controlled through the target adjusting mode, and the reliability of the compressor can be guaranteed while the exhaust temperature is reduced and the refrigerating and heating capacity is improved. And the heat exchange capacity of the economizer can be fully utilized, the refrigerant can be ensured to obtain sufficient supercooling degree, and the heat absorption capacity of the evaporator is improved.

Description

Technical Field

[0001] The present application relates to the technical field of heat pumps, and in particular to a heat pump system and a control method thereof. Background Art

[0002] With the improvement of science and technology, there are more and more technologies for heating and cooling indoor environments. Among them, heat pump technology can efficiently utilize low-temperature heat energy and is used in many fields such as domestic hot and cold water, air conditioning, and heating. In the current situation of tight energy supply and increasing environmental protection requirements, it has been widely used.

[0003] In traditional technology, the compressor of the heat pump system is supplemented with air to increase enthalpy to improve the cooling and heating capacity. This is the product of the expansion of heat pump technology into the low-temperature field. It can effectively reduce the exhaust temperature of the compressor and make the system operate reliably for a long time. However, in the above process, there is still the problem of suction liquid, which brings safety hazards to the operation of the heat pump system. Summary of the invention

[0004] The present application provides a heat pump system and a control method thereof to solve the technical problem of liquid inhalation during the process of replenishing air and increasing enthalpy of the compressor.

[0005] In a first aspect, some embodiments provide a heat pump system, comprising:

[0006] The refrigerant circulation loop allows the refrigerant to circulate in a loop consisting of a compressor, a four-way valve, an outdoor heat exchanger, a first throttling element, an economizer and an indoor heat exchanger;

[0007] The liquid injection enthalpy increase branch allows the refrigerant diverted from the refrigerant circulation circuit to flow from between the first throttling element and the main path of the economizer through the auxiliary path of the economizer into the air supply port of the compressor, and the liquid injection enthalpy increase branch is also provided with an air supply throttling element;

[0008] A temperature sensing component, used to obtain the exhaust temperature of the compressor, the auxiliary circuit inlet temperature and the auxiliary circuit outlet temperature of the economizer;

[0009] A pressure sensing element, used to obtain the exhaust pressure of the compressor;

[0010] The controller is configured as:

[0011] The exhaust superheat is obtained according to the exhaust temperature and the exhaust pressure, and an optional adjustment method for the opening of the air supply throttling element is determined according to the exhaust superheat, and the adjustment method at least includes increasing, decreasing and maintaining; the economizer superheat is obtained according to the auxiliary line inlet temperature and the auxiliary line outlet temperature, and a target adjustment method is determined from the optional adjustment methods based on the economizer superheat, and the opening of the air supply throttling element is controlled with the target adjustment method.

[0012] The above-mentioned heat pump system includes a refrigerant circulation circuit, so that the refrigerant circulates in a circuit composed of a compressor, a four-way valve, an outdoor heat exchanger, a first throttling element, an economizer and an indoor heat exchanger. It also includes a liquid injection enthalpy increase branch, which can divert the refrigerant in the refrigerant circulation circuit between the first throttling element and the main circuit of the economizer, and flow into the air supply port of the compressor through the auxiliary circuit of the economizer for air supply and enthalpy increase. Furthermore, an air supply throttling element is provided on the liquid injection enthalpy increase branch, and the controller can be connected to the temperature sensor assembly and the pressure sensor element to obtain the exhaust temperature and exhaust pressure of the compressor, as well as the auxiliary circuit inlet temperature and auxiliary circuit outlet temperature of the economizer. Then, the controller obtains the exhaust superheat according to the exhaust temperature and the exhaust pressure, and determines the optional adjustment method for the opening of the air supply throttling element according to the exhaust superheat, and the adjustment method at least includes increasing, decreasing and maintaining; the economizer superheat is obtained according to the auxiliary line inlet temperature and the auxiliary line outlet temperature, and the target adjustment method is determined from the optional adjustment methods based on the economizer superheat, and the opening of the air supply throttling element is controlled with the target adjustment method.

[0013] Among them, the optional adjustment mode of the opening of the air-supply throttling element is limited according to the exhaust superheat, and the target adjustment mode is determined from the optional adjustment modes in combination with the economizer superheat, so that the reliability of the compressor can be guaranteed while reducing the exhaust temperature and improving the cooling and heating capacity. For example, in the case of high exhaust superheat, which indicates that the exhaust temperature is high and the compressor load is increased, the optional adjustment mode of the air-supply throttling element can be limited to increase, so that the liquid injection enthalpy increase branch can be diverted to obtain more refrigerant circulation volume, give full play to the heat exchange performance of the economizer, and reduce the compressor exhaust temperature to ensure that the compressor exhaust superheat returns to a normal level. For the case of low exhaust superheat, which indicates that the refrigerant circulation volume in the refrigerant circulation loop is insufficient and the exhaust temperature is too low, there may be liquid return phenomenon, the optional adjustment mode of the air-supply throttling element can be limited to decrease, so as to reduce the refrigerant circulation volume obtained by the liquid injection enthalpy increase branch diversion, and ensure that there is enough refrigerant circulation volume in the refrigerant circulation loop to maintain the stable operation of the compressor. On the basis of the above, using the superheat of the economizer as a reference for selecting the target opening method of the air supply throttling element can ensure that the heat exchange capacity of the economizer is fully utilized, and that after passing through the main circuit of the economizer, the refrigerant can obtain sufficient subcooling to improve the heat absorption capacity of the evaporator. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 A schematic diagram of a refrigerant flow path in a heating mode of a heat pump system in one embodiment;

[0016] Figure 2 A schematic diagram of a refrigerant flow path in a refrigeration mode of a heat pump system in one embodiment;

[0017] Figure 3 is a schematic structural diagram of a heat pump system in one embodiment;

[0018] Figure 4 is a schematic structural diagram of a heat pump system in another embodiment;

[0019] Figure 5 A schematic structural diagram of a heat pump system in yet another embodiment;

[0020] Figure 6 A schematic diagram of the structure of a heat pump system in another embodiment;

[0021] Figure 7 A schematic diagram of the structure of a heat pump system in yet another embodiment;

[0022] Figure 8 A schematic flow chart of a heat pump system control method in one embodiment;

[0023] Fig. 9 A schematic flow chart of a heat pump system control method in another embodiment;

[0024] Fig.10 A schematic flow chart of a heat pump system control method in yet another embodiment;

[0025] Fig.11 A schematic flow chart of a heat pump system control method in another embodiment;

[0026] Fig.12 Schematic diagram of a flow chart of a heat pump system control method in yet another embodiment. DETAILED DESCRIPTION

[0027] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application as detailed in the claims.

[0028] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0029] The terms "first", "second", "third", etc. in the specification and claims of this application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise noted. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances.

[0030] The terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0031] The term "module" refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and / or software code that is capable of performing the functions associated with that element.

[0032] See also Figure 1 , is a schematic diagram of the internal structure of a heat pump system provided in an embodiment of the present application, wherein the internal components include: a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a first throttling element 4, an economizer 5 and an indoor heat exchanger 6. The above components can be connected via pipelines to form a refrigerant circulation loop for circulating the refrigerant to realize the cooling and heating functions of the heat pump system.

[0033] It can be understood that the heat pump system can switch between the cooling mode and the heating mode by switching the four-way valve 2. Figure 1As shown, in the heating mode, the low-temperature and low-pressure gaseous refrigerant is sucked into the compressor 1 from the air intake port and becomes a high-temperature and high-pressure gas after being pressurized. The high-temperature and high-pressure gas then enters the indoor heat exchanger 6 (used as a condenser at this time) through the four-way valve 2, where the refrigerant releases heat through the condensation and liquefaction process, and this heat is transferred to the indoor air, thereby increasing the temperature of the indoor air. The liquid refrigerant after condensation and liquefaction is decompressed through the first throttling element 4 to reduce its pressure and temperature in preparation for the next evaporation process. At this point, the liquid refrigerant can also be supercooled again through the economizer 5 so that the refrigerant has a higher refrigeration efficiency when entering the evaporator. The decompressed liquid refrigerant enters the outdoor heat exchanger 3 (used as an evaporator at this time). In the evaporator, the refrigerant absorbs the heat of the outdoor air through the evaporation and gasification process, thereby becoming a low-temperature and low-pressure gaseous refrigerant, which is sucked into the compressor 1 again to start the next cycle. This process is repeated, and through the continuous liquefaction and gasification cycle, heat is transferred from the outdoor to the indoor, achieving the purpose of heating.

[0034] like Figure 2 As shown, in the cooling mode, the low-temperature and low-pressure gaseous refrigerant is sucked into the compressor 1 from the air intake port and becomes a high-temperature and high-pressure gas after being pressurized. The high-temperature and high-pressure gas then enters the outdoor heat exchanger 3 (used as a condenser at this time) through the four-way valve 2. Through heat exchange in the condenser, the heat carried by the hot vapor is effectively released and blown out of the machine through the outdoor unit outlet. The low-temperature and high-pressure liquid refrigerant after condensation and liquefaction can also be supercooled again through the economizer 5 so that the refrigerant has a higher refrigeration efficiency when entering the evaporator. Subsequently, the supercooled high-pressure liquid refrigerant is decompressed through the first throttling element 4 to reduce its pressure and temperature in preparation for the next evaporation process. The low-temperature and low-pressure liquid refrigerant enters the indoor heat exchanger 6 (used as an evaporator at this time). In the evaporator, the liquid refrigerant vaporizes and absorbs a large amount of heat. Due to the heat absorption effect, the air temperature around the evaporator decreases accordingly, and then the indoor unit fan blows the low-temperature air into the room through the outlet, thereby reducing the temperature of the indoor air. The refrigerant vaporized in the evaporator turns back into low-temperature and low-pressure gaseous refrigerant and is sucked into the compressor 1 again to start the next cycle. This process is repeated, and through the continuous cycle of liquefaction and vaporization, heat is transferred from indoors to outdoors, achieving the purpose of cooling.

[0035] It should be noted that, based on the different heat exchange principles of the outdoor heat exchanger 3 and the indoor heat exchanger 6 when used as condensers, for example, it can be air cooling, water cooling or other heat exchange forms, the heat pump system can correspond to different forms of heat pump systems, and the embodiments of the present application are not limited to this.

[0036] In an exemplary embodiment, please continue to refer to Figure 1 and Figure 2The heat pump system also includes: a liquid injection reheat increase branch, which allows the refrigerant diverted from the refrigerant circulation circuit to flow from the main path between the first throttling element 4 and the economizer 5, through the auxiliary path of the economizer 5 into the air supply port of the compressor 1, and an air supply throttling element 7 is also provided on the liquid injection reheat increase branch.

[0037] Among them, the liquid injection enthalpy increase branch is used to connect with the air supply port of the compressor to supplement the refrigerant for the medium-pressure chamber of the compressor 1, so as to increase the high-temperature and high-pressure refrigerant circulation volume output by the compressor 1. Specifically, the economizer 5 includes a main circuit (lower circuit) and an auxiliary circuit (upper circuit). The inlet of the main circuit is connected to the condenser side, and the outlet of the main circuit is connected to the evaporator side, which is used to supercool the low-temperature refrigerant after heat release through the condenser into a liquid state. The inlet of the auxiliary circuit is connected between the first throttling element 4 and the economizer 5 through the air supply throttling element 7, and the outlet of the auxiliary circuit is connected to the air supply port of the compressor 1. The air supply throttling element 7 is used to throttle and cool the refrigerant diverted from the refrigerant circulation loop. The throttled refrigerant enters the auxiliary circuit of the economizer 5, exchanges heat with the main circuit, absorbs heat and evaporates into medium-pressure superheated steam, and enters the compressor 1 for enthalpy increase to improve the cooling and heating energy efficiency of the heat pump system.

[0038] For example, a one-way valve is also provided on the pipeline connecting the outlet of the auxiliary circuit of the economizer 5 to the air supply port of the compressor 1. The one-way valve is used to ensure that the refrigerant can only flow from the auxiliary circuit of the economizer 5 to the air supply port of the compressor 1, effectively avoiding the refrigerant from flowing back in the pipeline, resulting in overheating and damage of the economizer 5.

[0039] In an exemplary embodiment, the heat pump system further includes a temperature sensing component for obtaining the exhaust temperature of the compressor, the auxiliary line inlet temperature and the auxiliary line outlet temperature of the economizer; and a pressure sensing element for obtaining the exhaust pressure of the compressor.

[0040] Please continue to refer to Figure 1 and Figure 2 , the temperature sensing assembly may include a first temperature sensor 8, a second temperature sensor 9 and a third temperature sensor 10. Among them, the first temperature sensor 8 can be set at any position on the connecting pipeline between the compressor 1 and the condenser. For example, the embodiment of the present application can be set at the exhaust port of the compressor 1 to detect the exhaust temperature of the compressor 1. The second temperature sensor 9 is set at the auxiliary road inlet of the economizer 5 to detect the auxiliary road inlet temperature of the economizer 5. The third temperature sensor 10 is set at the auxiliary road outlet of the economizer 5 to detect the auxiliary road outlet temperature of the economizer 5. The pressure sensing element is a pressure sensor 11, which can be set at the exhaust port of the compressor 1 to detect the exhaust pressure of the compressor 1.

[0041] Exemplarily, the specific device selection of the temperature sensor and the pressure sensor is not limited, and those skilled in the art can select according to actual technical requirements.

[0042] In an exemplary embodiment, the heat pump system further includes a controller (not shown in the figure). The controller is the main control center of the heat pump system and can be used to connect various sensor elements provided in the heat pump system to analyze the operating status and control the operating parameters of core components such as the compressor 1, the outdoor heat exchanger 3 and the indoor heat exchanger 6. At the same time, the controller can also be used to control the opening and closing states of various pumps and valve elements in the refrigerant circulation loop and branches to ensure that the refrigerant circulates and produces heat more efficiently.

[0043] In an exemplary embodiment, please continue to refer to Figure 1 and Figure 2 The controller is configured as follows: obtaining the exhaust superheat according to the exhaust temperature and the exhaust pressure, and determining the optional adjustment method for the opening of the air supply throttling element 7 according to the exhaust superheat, the adjustment method at least including increasing, decreasing and maintaining; obtaining the economizer superheat according to the auxiliary line inlet temperature and the auxiliary line outlet temperature, determining the target adjustment method from the optional adjustment methods based on the economizer superheat, and controlling the opening of the air supply throttling element 7 with the target adjustment method.

[0044] Among them, the exhaust superheat is used to measure the degree to which the temperature of the refrigerant gas discharged by the compressor 1 is higher than the saturation temperature corresponding to its pressure, which is critical for ensuring the stable operation of the compressor and the heat pump system. Specifically, the exhaust superheat can be determined by the exhaust temperature of the compressor and the outlet temperature of the condenser, or it can be determined by the exhaust temperature of the compressor and the saturation temperature corresponding to the exhaust pressure. For example, in an embodiment of the present application, the saturation temperature corresponding to the exhaust pressure of the compressor 1 can be calculated first, and then the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure can be calculated, which is the exhaust superheat of the compressor 1.

[0045] It can be understood that if the exhaust superheat is too high, it means that the exhaust temperature exceeds the saturation temperature corresponding to its pressure to a high degree, that is, it means that the exhaust temperature is high, which may cause the compressor load to increase, the power consumption to increase, and may cause equipment damage or safety accidents. In this case, the air supplement throttling element 7 can be effectively adjusted so that the liquid injection enthalpy increase branch can be diverted to obtain more refrigerant circulation volume, give full play to the heat exchange performance of the economizer 5, and at the same time reduce the compressor exhaust temperature to ensure that the compressor exhaust superheat returns to a normal level. Exemplarily, the air supplement throttling element 7 is effectively adjusted so that the liquid injection enthalpy increase branch can be diverted to obtain more refrigerant circulation volume, and the optional adjustment method of the opening of the air supplement throttling element 7 can be limited to increasing.

[0046] The exhaust superheat is too low, which indicates that the exhaust temperature exceeds the saturation temperature corresponding to its pressure to a low degree, which indicates that the refrigerant circulation amount in the refrigerant circulation loop is insufficient, resulting in too low exhaust temperature, which may lead to liquid return, affect the oil separation effect, and even damage the compressor. Correspondingly, in this case, the air supplement throttling element 7 can be effectively adjusted to reduce the refrigerant circulation amount obtained by the liquid injection enthalpy increase branch diversion, to ensure that there is enough refrigerant circulation in the refrigerant circulation loop to maintain stable operation of the compressor. Exemplarily, the air supplement throttling element 7 is effectively adjusted to reduce the refrigerant circulation amount obtained by the liquid injection enthalpy increase branch diversion, which can be to limit the optional adjustment method of the opening of the air supplement throttling element 7 to a small adjustment.

[0047] Of course, when the exhaust superheat is within the normal range, the optional adjustment method for the opening of the air supply throttling element 7 can be any method without limitation. For example, the adjustment method can be to increase, decrease, or keep it unchanged.

[0048] After determining the optional adjustment method for the opening of the air supply throttling element 7 based on the exhaust superheat, it is also necessary to determine the target adjustment method from the determined optional adjustment methods based on the economizer superheat to adjust the opening of the air supply throttling element 7 according to the selected target adjustment method.

[0049] The economizer superheat is the difference between the auxiliary line inlet temperature and the auxiliary line outlet temperature. The economizer superheat is used as a reference for controlling the opening of the air supply throttling element 7 to ensure that the heat exchange capacity of the economizer is fully utilized and that the refrigerant can obtain sufficient supercooling after passing through the main line of the economizer to improve the heat absorption capacity of the evaporator.

[0050] The above-mentioned heat pump system limits the optional adjustment method for the opening of the air supply throttling element according to the exhaust superheat, and then determines the target adjustment method from the optional adjustment methods in combination with the economizer superheat. This can ensure the reliability of the compressor while reducing the exhaust temperature and improving the cooling and heating capacity.

[0051] In an exemplary embodiment, the controller is further configured as follows: if the exhaust superheat is greater than a first exhaust superheat threshold, determining that the optional adjustment methods for the opening of the air supply throttling element include increasing and maintaining; if the exhaust superheat is less than a second exhaust superheat threshold, determining that the optional adjustment methods for the opening of the air supply throttling element include decreasing and maintaining; if the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold, determining that the optional adjustment methods for the opening of the air supply throttling element include increasing, decreasing and maintaining; wherein, the first exhaust superheat threshold is greater than the second exhaust superheat threshold.

[0052] Specifically, the first exhaust superheat threshold is the upper threshold of the compressor exhaust superheat, and exceeding this threshold indicates that the exhaust superheat is high. The second exhaust superheat threshold is the lower threshold of the compressor exhaust superheat, and being lower than this threshold indicates that the exhaust superheat is too low. The specific values ​​of the first exhaust superheat threshold and the second exhaust superheat threshold are not limited, and can be determined comprehensively based on the type of compressor, working environment and load conditions. For example, in an embodiment of the present application, the first exhaust superheat threshold can be set to 40°C, and the second exhaust superheat threshold can be set to 35°C.

[0053] Furthermore, if the exhaust superheat is greater than the first exhaust superheat threshold, it indicates that the exhaust temperature exceeds the saturation temperature corresponding to its pressure to a high degree, that is, the exhaust temperature is high, which may cause the compressor load to increase, increase power consumption, and may cause equipment damage or safety accidents. It can be determined that the optional adjustment method for the opening of the air injection throttling element includes increasing and maintaining, so that the liquid injection enthalpy increase branch can be diverted to obtain more refrigerant circulation volume, give full play to the heat exchange performance of the economizer, and reduce the compressor exhaust temperature to ensure that the compressor exhaust superheat returns to a normal level.

[0054] If the exhaust superheat is less than the second exhaust superheat threshold, it indicates that the exhaust temperature exceeds the saturation temperature corresponding to its pressure to a low degree, which indicates that the refrigerant circulation amount in the refrigerant circulation loop is insufficient, resulting in too low exhaust temperature, which may lead to liquid return, affect the oil separation effect, and even damage the compressor. It can be determined that the optional adjustment methods for the opening of the air supplement throttling element include reducing and maintaining, so as to reduce the refrigerant circulation amount obtained by the liquid injection enthalpy increase branch flow, and ensure that there is enough refrigerant circulation in the refrigerant circulation loop to maintain the stable operation of the compressor.

[0055] If the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold and is within the normal range, it can be determined that the optional adjustment method for the opening of the air supply throttling element can be any method without limitation, and can include increasing, decreasing and maintaining.

[0056] In an exemplary embodiment, the controller is further configured to: determine the current adjustment mode based on the comparison result between the economizer superheat and the target economizer superheat; if the current adjustment mode is an optional adjustment mode, determine the current adjustment mode as the target adjustment mode; otherwise, determine the target adjustment mode as maintaining.

[0057] Specifically, the target economizer superheat is a target value for maintaining the economizer superheat, which can be set based on the efficiency and stability of the heat pump system and the risk of compressor liquid hammer. In this embodiment, based on the comparison result between the economizer superheat and the target economizer superheat, the current adjustment mode can be determined, that is, whether it is necessary to adjust the opening of the air supply throttling element and how to adjust the opening of the air supply throttling element, so as to achieve the purpose of maintaining the economizer superheat at the target economizer superheat.

[0058] Exemplarily, the controller is further configured to: if the economizer superheat meets the target economizer superheat, determine that the current adjustment mode is to maintain; if the economizer superheat exceeds the target economizer superheat, determine that the current adjustment mode is to increase; if the economizer superheat is lower than the target economizer superheat, determine that the current adjustment mode is to decrease.

[0059] Among them, if the economizer superheat exceeds the target economizer superheat, it means that the refrigerant circulation volume obtained by the liquid injection enthalpy increase branch diversion is insufficient, so in order to improve the heat exchange performance of the economizer, the current adjustment method can be determined to be increased. If the economizer superheat is lower than the target economizer superheat, it means that the refrigerant circulation volume obtained by the liquid injection enthalpy increase branch diversion exceeds the heat exchange demand, and the current adjustment method can be determined to be decreased.

[0060] For example, the method of determining whether the economizer superheat meets the target economizer superheat may be to calculate the difference between the economizer superheat and the target economizer superheat to obtain the economizer superheat difference. If the economizer superheat difference falls within a preset difference range, it indicates that the economizer superheat meets the target economizer superheat. If the economizer superheat difference is greater than the preset difference range, it indicates that the economizer superheat exceeds the target economizer superheat. If the economizer superheat difference is less than the preset difference range, it indicates that the economizer superheat is lower than the target economizer superheat.

[0061] Furthermore, after the current adjustment mode is determined according to the economizer superheat, it is necessary to match it with the optional adjustment mode to obtain the target adjustment mode to ensure that the target adjustment mode meets the exhaust superheat restriction requirements. Specifically, when the current adjustment mode belongs to the optional adjustment mode, the current adjustment mode is determined to be the target adjustment mode; otherwise, the target adjustment mode is determined to be maintained. It can be understood that if the adjustment mode determined according to the economizer superheat does not meet the exhaust superheat restriction requirements, the current opening of the air supply throttling element must be kept unchanged to avoid affecting the operating reliability of the compressor. If the adjustment mode determined according to the economizer superheat meets the exhaust superheat restriction requirements, the opening of the air supply throttling element can be adjusted directly according to the current adjustment mode.

[0062] It should be noted that when the target adjustment mode is determined to be increasing or decreasing, the air supply throttling element can be adjusted according to a fixed adjustment step until the economizer superheat meets the target economizer superheat. If the target adjustment mode is increasing and the opening of the air supply throttling element has reached the maximum opening threshold, the current opening can be maintained; if the target adjustment mode is decreasing and the opening of the air supply throttling element has reached the minimum opening threshold, the current opening can be maintained.

[0063] In addition, after adjusting the air supply throttling element, the adjustment interval time may be waited, and then the above temperature and pressure parameters are obtained, and the exhaust gas superheat and economizer superheat are analyzed to further determine whether the air supply throttling element needs to be adjusted. In this embodiment, during the process of adjusting the air supply throttling element, the adjustment interval time is set to avoid frequent fluctuations in the system due to the opening adjustment of the throttling element, which is conducive to ensuring the operating stability of the heat pump system.

[0064] In an exemplary embodiment, Figure 3 As shown, the liquid injection enthalpy increase branch is also provided with a gas-liquid separation element 12 and a first solenoid valve 13. The refrigerant flowing out through the auxiliary circuit of the economizer 5 enters the gas-liquid separation element 12, and the separated gaseous refrigerant is replenished into the air supply port of the compressor 1. The separated liquid refrigerant flows into the air intake port of the compressor 1 through the first solenoid valve 13.

[0065] Specifically, the refrigerant flowing out through the auxiliary circuit of the economizer 5 can enter from the middle of the gas-liquid separation element 12. Under the action of gravity, the gaseous refrigerant will be output from the upper part of the gas-liquid separation element 12, and replenished into the air supply port of the compressor 1 through the one-way valve, so as to increase the enthalpy of the compressor 1 by replenishing the air. The liquid refrigerant will flow out from the lower part of the gas-liquid separation element 12, and flow into the air intake port of the compressor 1 through the first solenoid valve 13, so as to avoid the risk of liquid compression, and at the same time realize liquid spray cooling of the compressor. For example, on the pipeline where the liquid refrigerant flows into the air intake port of the compressor 1 through the first solenoid valve 13, a throttling element such as a capillary tube can also be provided to throttle and cool the refrigerant coming out of the auxiliary circuit of the economizer 5 through heat exchange.

[0066] In an exemplary embodiment, the controller is further configured to open the first solenoid valve if the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold and the economizer superheat is lower than the target economizer superheat.

[0067] Specifically, the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold, indicating that the exhaust superheat is in the normal exhaust superheat range, and the economizer superheat is lower than the target economizer superheat, indicating that the refrigerant circulation amount obtained by diverting the liquid injection reheat increase branch is too much. In order to avoid the risk of liquid compression caused by bringing liquid back to the compressor medium pressure chamber from the liquid injection reheat increase branch, the first solenoid valve 13 needs to be opened to allow the separated liquid refrigerant to flow back to the suction port of the compressor 1.

[0068] In an exemplary embodiment, the controller is also configured to: record a first time when the operating frequency of the compressor is greater than a preset operating frequency; when the first time exceeds a preset duration, open the air supply throttling element and adjust the opening of the air supply throttling element to a minimum opening threshold.

[0069] Specifically, the controller can determine whether to open the air supplement throttling element according to the operating state of the compressor, so as to supplement the compressor with air and increase enthalpy through the liquid injection enthalpy increase branch. The operating state of the compressor can be described by the operating frequency of the compressor, or can be described comprehensively based on the exhaust pressure and suction pressure of the compressor.

[0070] Exemplarily, this embodiment can set a preset operating frequency as the opening condition of the air-supply throttling element. Specifically, the operating frequency of the compressor can be obtained in real time. When it is detected that the operating frequency of the compressor is greater than the preset operating frequency, it indicates that the heating and cooling energy efficiency of the compressor is low and cannot meet the current heating or cooling needs. Then, the first time can be recorded to determine whether the operating frequency of the compressor is greater than the preset operating frequency for a preset time. When the first time exceeds the preset time, the air-supply throttling element is opened to supplement the compressor with air and increase enthalpy by diverting the refrigerant obtained through the liquid injection enthalpy increase branch, thereby improving the heating and cooling capacity of the heat pump system. Among them, the specific values ​​of the preset operating frequency and the preset time can be selected according to actual technical requirements. For example, in this embodiment, the preset operating frequency is set to 35Hz, and the preset time is set to 10 minutes.

[0071] In an exemplary embodiment, Figure 4 As shown, the heat pump system further includes: a liquid bypass branch, so that the refrigerant diverted from the refrigerant circulation loop flows into the suction port of the compressor 1 from between the indoor heat exchanger 6 and the main circuit of the economizer 5, and a second solenoid valve 14 is also provided on the liquid bypass branch. The controller is further configured to: open the second solenoid valve 14 if the exhaust temperature is greater than the exhaust temperature threshold.

[0072] Specifically, the liquid bypass branch is opened only when the compressor exhaust temperature is high. The exhaust temperature threshold is a temperature value of the exhaust temperature being high. When the exhaust temperature is greater than the exhaust temperature threshold, the controller can open the second solenoid valve 14 to allow the liquid refrigerant to directly return to the suction port of the compressor 1 through the liquid bypass branch, cool the compressor, quickly reduce the exhaust temperature, and ensure stable operation of the heat pump system.

[0073] The specific value of the exhaust temperature threshold may be selected according to actual technical requirements. For example, in this embodiment, the exhaust temperature threshold is set to 100°C.

[0074] When the heat pump system is in heating mode, the liquid refrigerant condensed and liquefied in the indoor heat exchanger 6 can flow directly back to the suction port of the compressor 1 through the liquid bypass branch, quickly lowering the exhaust temperature while reducing the flash of the refrigerant during the circulation process from the indoor heat exchanger 6 to the outdoor heat exchanger 3, thereby avoiding the attenuation of the heating capacity of the heat pump system and expanding the scope of use of the system.

[0075] When the heat pump system is in cooling mode, the liquid refrigerant supercooled by the economizer 5 can flow directly back to the suction port of the compressor 1 through the liquid bypass branch, quickly lowering the exhaust temperature while reducing the flash of the refrigerant during the circulation process from the outdoor heat exchanger 3 to the indoor heat exchanger 6, thereby avoiding the attenuation of the cooling capacity of the heat pump system and expanding the scope of use of the system.

[0076] In an exemplary embodiment, Figure 5 and Figure 6 As shown, the heat pump system further includes: a second throttling element 15, located between the indoor heat exchanger 6 and the main circuit of the economizer 5, wherein the first throttling element 4 and the second throttling element 15 are both one-way throttling valves.

[0077] Among them, the one-way throttle valve is a valve that controls the flow of fluid by changing the throttling section or throttling length. When the fluid flows through the one-way throttle valve from one direction, it can flow freely, but in the other direction, it has a throttling effect, that is, it can limit the flow of the fluid. The one-way throttle valve is usually composed of a valve body, a valve core, a spring and other components. When the fluid flows in from the inlet end, the valve core moves under the pressure, opening the channel to allow the fluid to flow through. At this time, the one-way throttle valve acts as a one-way valve, allowing the fluid to flow in one direction only. When the fluid flows in from the other direction (i.e., the outlet end), the valve core will block part of the channel and play a throttling role. The flow of the fluid can be controlled by adjusting the gap between the valve core and the valve seat.

[0078] Specifically, refer to Figure 5When the heat pump system is in cooling mode, the refrigerant flows from the outdoor heat exchanger 3 through the first throttling element 4 into the main circuit of the economizer 5. At this time, the first throttling element 4 is in a passage state, and the refrigerant can flow freely through the first throttling element 4. When the refrigerant completes the heat exchange from the main circuit of the economizer 5, it flows into the indoor heat exchanger 6 through the second throttling element 15. At this time, the second throttling element 15 is in a throttling state, and the refrigerant can be reduced in pressure and temperature due to the throttling effect of the second throttling element 15.

[0079] Reference Figure 6 When the heat pump system is in heating mode, the refrigerant flows from the indoor heat exchanger 6 into the main circuit of the economizer 5 through the second throttling element 15. At this time, the second throttling element 15 is in a passage state, and the refrigerant can flow freely through the second throttling element 15. When the refrigerant completes the heat exchange from the main circuit of the economizer 5, it flows into the outdoor heat exchanger 3 through the first throttling element 4. At this time, the first throttling element 4 is in a throttling state, and the refrigerant can be reduced in pressure and temperature due to the throttling effect of the first throttling element 4.

[0080] In this embodiment, by providing one-way throttle valves at both ends of the economizer, it can be ensured that no matter in the heating mode or the cooling mode, the refrigerant is not throttled before being supercooled by the economizer, but the refrigerant is throttled after being supercooled by the economizer, so as to improve the supercooling capacity of the economizer, thereby improving the heating and cooling capacity of the heat pump system.

[0081] Exemplarily, the controller is further configured to: control the opening of the first throttling element when the operation mode of the heat pump system is the heating mode; and control the opening of the second throttling element when the operation mode of the heat pump system is the cooling mode.

[0082] Specifically, the controller can control the opening of the first throttling element / the second throttling element during the operation of the heat pump system according to the operating state of the compressor, so as to adjust the refrigerant circulation amount in the refrigerant circulation loop to ensure the stable operation of the system for cooling and heating. Among them, the data basis for controlling the opening of the first throttling element / the second throttling element is not unique, and it can be controlled according to the suction superheat of the compressor and the target suction superheat, or according to the exhaust superheat of the compressor and the target exhaust superheat, or according to the operating parameters of the indoor heat exchanger 3 or the outdoor heat exchanger 6, or according to any combination of the above operating parameters. It can be selected according to technical requirements, as long as the refrigerant circulation amount in the refrigerant circulation loop can be adjusted to ensure the stable operation of the system for cooling and heating.

[0083] In an exemplary embodiment, Figure 7As shown, the heat pump system further includes: an air bypass branch, so that the refrigerant diverted from the refrigerant circulation circuit flows from the exhaust port of the compressor 1 into the suction port of the compressor 1, and a third solenoid valve 16 is also arranged on the air bypass branch. The controller is further configured to: open the third solenoid valve 16 if the exhaust pressure is greater than the exhaust pressure threshold.

[0084] Specifically, the gas bypass branch is opened only when the exhaust pressure of the compressor is high. The exhaust pressure threshold is the pressure value of the high exhaust pressure. When the exhaust pressure is greater than the exhaust pressure threshold, the controller can open the third solenoid valve 16 to interconnect the air intake and exhaust ports of the compressor 1 to quickly reduce the exhaust pressure and ensure stable operation of the heat pump system.

[0085] The specific value of the exhaust pressure threshold may be selected according to actual technical requirements. For example, in this embodiment, the exhaust pressure threshold is set to 3.8 MPa.

[0086] It should be noted that after the liquid bypass branch is controlled to be turned on by the controller, the controller can close the second solenoid valve 14 to shut off the liquid bypass branch when the exhaust temperature drops to the closing temperature threshold. The closing temperature threshold is less than the exhaust temperature threshold. Similarly, after the gas bypass branch is controlled to be turned on by the controller, the controller can close the third solenoid valve 16 to shut off the gas bypass branch when the exhaust pressure drops to the closing pressure threshold. The closing pressure threshold is less than the exhaust pressure threshold.

[0087] In an exemplary embodiment, Figure 8 As shown, a heat pump system control method is provided, which is applicable to the heat pump system described in any of the above embodiments. The heat pump system control method is executed by a controller in the heat pump system. The method includes the following steps 202 to 208, wherein:

[0088] Step 202, obtaining exhaust gas superheat according to exhaust gas temperature and exhaust gas pressure;

[0089] Step 204, determining an optional adjustment method for the opening of the air supply throttling element according to the exhaust gas superheat, the adjustment method at least including increasing, decreasing and maintaining;

[0090] Step 206, obtaining the economizer superheat according to the auxiliary line inlet temperature and the auxiliary line outlet temperature;

[0091] Step 208: determine a target regulation mode from optional regulation modes based on the economizer superheat, and control the opening of the air supply throttling element in the target regulation mode.

[0092] Among them, the exhaust superheat is used to measure the degree to which the temperature of the refrigerant gas discharged from the compressor is higher than the saturation temperature corresponding to its pressure, which is critical to ensure the stable operation of the compressor and the heat pump system. Specifically, the exhaust superheat can be determined by the exhaust temperature of the compressor and the outlet temperature of the condenser, or it can be determined by the exhaust temperature of the compressor and the saturation temperature corresponding to the exhaust pressure. For example, in an embodiment of the present application, the saturation temperature corresponding to the exhaust pressure of the compressor can be calculated first, and then the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure can be calculated, which is the exhaust superheat of the compressor.

[0093] It can be understood that if the exhaust superheat is too high, it means that the exhaust temperature exceeds the saturation temperature corresponding to its pressure to a high degree, that is, it means that the exhaust temperature is high, which may lead to an increase in the compressor load and power consumption, and may cause equipment damage or safety accidents. In this case, the air supplement throttling element can be effectively adjusted so that the liquid injection enthalpy increase branch can be diverted to obtain more refrigerant circulation volume, give full play to the heat exchange performance of the economizer, and reduce the compressor exhaust temperature to ensure that the compressor exhaust superheat returns to a normal level. Exemplarily, the air supplement throttling element can be effectively adjusted so that the liquid injection enthalpy increase branch can be diverted to obtain more refrigerant circulation volume, and the optional adjustment method of the opening of the air supplement throttling element can be limited to increasing.

[0094] The exhaust superheat is too low, which indicates that the exhaust temperature exceeds the saturation temperature corresponding to its pressure to a low degree, which indicates that the refrigerant circulation amount in the refrigerant circulation loop is insufficient, resulting in too low exhaust temperature, which may lead to liquid return, affect the oil separation effect, and even damage the compressor. Correspondingly, in this case, the air supplement throttling element can be effectively adjusted to reduce the refrigerant circulation amount obtained by the liquid injection enthalpy increase branch diversion, to ensure that there is enough refrigerant circulation in the refrigerant circulation loop to maintain stable operation of the compressor. Exemplarily, the air supplement throttling element is effectively adjusted to reduce the refrigerant circulation amount obtained by the liquid injection enthalpy increase branch diversion, which can be to limit the optional adjustment method of the opening of the air supplement throttling element to a small adjustment.

[0095] Of course, when the exhaust superheat is within the normal range, the optional adjustment method for the opening of the air supply throttling element can be any method without limitation. For example, the adjustment method can be to increase, decrease, or keep it unchanged.

[0096] After determining the optional adjustment method for the opening of the air supply throttling element based on the exhaust superheat, it is also necessary to determine the target adjustment method from the determined optional adjustment methods based on the economizer superheat to adjust the opening of the air supply throttling element according to the selected target adjustment method.

[0097] Among them, the superheat of the economizer is the difference between the auxiliary line inlet temperature and the auxiliary line outlet temperature. Using the superheat of the economizer as a reference for controlling the opening of the air supply throttling element can ensure that the heat exchange capacity of the economizer is fully utilized, and that after passing through the main line of the economizer, the refrigerant can obtain sufficient supercooling to improve the heat absorption capacity of the evaporator.

[0098] In an exemplary embodiment, Fig. 9 As shown, the heat pump system control method further includes the following steps 302 to 306, wherein:

[0099] Step 302, if the exhaust gas superheat is greater than the first exhaust gas superheat threshold, determining that the optional adjustment method for the opening of the air supplement throttling element includes increasing and maintaining;

[0100] Step 304, if the exhaust gas superheat is less than the second exhaust gas superheat threshold, determining that the optional adjustment method for the opening of the air supplement throttling element includes decreasing and maintaining;

[0101] Step 306, if the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold, determining the optional adjustment method for the opening of the air supplement throttling element includes increasing, decreasing and maintaining;

[0102] The first exhaust gas superheat threshold is greater than the second exhaust gas superheat threshold.

[0103] Specifically, the first exhaust superheat threshold is the upper threshold of the compressor exhaust superheat, and exceeding this threshold indicates that the exhaust superheat is high. The second exhaust superheat threshold is the lower threshold of the compressor exhaust superheat, and being lower than this threshold indicates that the exhaust superheat is too low. The specific values ​​of the first exhaust superheat threshold and the second exhaust superheat threshold are not limited, and can be determined comprehensively based on the type of compressor, working environment and load conditions. For example, in an embodiment of the present application, the first exhaust superheat threshold can be set to 40°C, and the second exhaust superheat threshold can be set to 35°C.

[0104] Furthermore, if the exhaust superheat is greater than the first exhaust superheat threshold, it indicates that the exhaust temperature exceeds the saturation temperature corresponding to its pressure to a high degree, that is, the exhaust temperature is high, which may cause the compressor load to increase, increase power consumption, and may cause equipment damage or safety accidents. It can be determined that the optional adjustment method for the opening of the air injection throttling element includes increasing and maintaining, so that the liquid injection enthalpy increase branch can be diverted to obtain more refrigerant circulation volume, give full play to the heat exchange performance of the economizer, and reduce the compressor exhaust temperature to ensure that the compressor exhaust superheat returns to a normal level.

[0105] If the exhaust superheat is less than the second exhaust superheat threshold, it indicates that the exhaust temperature exceeds the saturation temperature corresponding to its pressure to a low degree, which indicates that the refrigerant circulation amount in the refrigerant circulation loop is insufficient, resulting in too low exhaust temperature, which may lead to liquid return, affect the oil separation effect, and even damage the compressor. It can be determined that the optional adjustment methods for the opening of the air supplement throttling element include reducing and maintaining, so as to reduce the refrigerant circulation amount obtained by the liquid injection enthalpy increase branch flow, and ensure that there is enough refrigerant circulation in the refrigerant circulation loop to maintain the stable operation of the compressor.

[0106] If the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold and is within the normal range, it can be determined that the optional adjustment method for the opening of the air supply throttling element can be any method without limitation, and can include increasing, decreasing and maintaining.

[0107] In an exemplary embodiment, Fig.10 As shown, the heat pump system control method further includes the following steps 402 to 404, wherein:

[0108] Step 402, determining a current adjustment mode based on a comparison result between the economizer superheat and the target economizer superheat;

[0109] Step 404: if the current adjustment mode is an optional adjustment mode, the current adjustment mode is determined to be the target adjustment mode; otherwise, the target adjustment mode is determined to be maintained.

[0110] Specifically, the target economizer superheat is a target value for maintaining the economizer superheat, which can be set based on the efficiency and stability of the heat pump system and the risk of compressor liquid hammer. In this embodiment, based on the comparison result between the economizer superheat and the target economizer superheat, the current adjustment mode can be determined, that is, whether it is necessary to adjust the opening of the air supply throttling element and how to adjust the opening of the air supply throttling element, so as to achieve the purpose of maintaining the economizer superheat at the target economizer superheat.

[0111] Exemplarily, the controller is further configured to: if the economizer superheat meets the target economizer superheat, determine that the current adjustment mode is to maintain; if the economizer superheat exceeds the target economizer superheat, determine that the current adjustment mode is to increase; if the economizer superheat is lower than the target economizer superheat, determine that the current adjustment mode is to decrease.

[0112] Among them, if the economizer superheat exceeds the target economizer superheat, it means that the refrigerant circulation volume obtained by the liquid injection enthalpy increase branch diversion is insufficient, so in order to improve the heat exchange performance of the economizer, the current adjustment method can be determined to be increased. If the economizer superheat is lower than the target economizer superheat, it means that the refrigerant circulation volume obtained by the liquid injection enthalpy increase branch diversion exceeds the heat exchange demand, and the current adjustment method can be determined to be decreased.

[0113] For example, the method of determining whether the economizer superheat meets the target economizer superheat may be to calculate the difference between the economizer superheat and the target economizer superheat to obtain the economizer superheat difference. If the economizer superheat difference falls within a preset difference range, it indicates that the economizer superheat meets the target economizer superheat. If the economizer superheat difference is greater than the preset difference range, it indicates that the economizer superheat exceeds the target economizer superheat. If the economizer superheat difference is less than the preset difference range, it indicates that the economizer superheat is lower than the target economizer superheat.

[0114] Furthermore, after the current adjustment mode is determined according to the economizer superheat, it is necessary to match it with the optional adjustment mode to obtain the target adjustment mode to ensure that the target adjustment mode meets the exhaust superheat restriction requirements. Specifically, when the current adjustment mode belongs to the optional adjustment mode, the current adjustment mode is determined to be the target adjustment mode; otherwise, the target adjustment mode is determined to be maintained. It can be understood that if the adjustment mode determined according to the economizer superheat does not meet the exhaust superheat restriction requirements, the current opening of the air supply throttling element must be kept unchanged to avoid affecting the operating reliability of the compressor. If the adjustment mode determined according to the economizer superheat meets the exhaust superheat restriction requirements, the opening of the air supply throttling element can be adjusted directly according to the current adjustment mode.

[0115] It should be noted that when the target adjustment mode is determined to be increasing or decreasing, the air supply throttling element can be adjusted according to a fixed adjustment step until the economizer superheat meets the target economizer superheat. If the target adjustment mode is increasing and the opening of the air supply throttling element has reached the maximum opening threshold, the current opening can be maintained; if the target adjustment mode is decreasing and the opening of the air supply throttling element has reached the minimum opening threshold, the current opening can be maintained.

[0116] In addition, after adjusting the air supply throttling element, the adjustment interval time may be waited, and then the above temperature and pressure parameters are obtained, and the exhaust gas superheat and economizer superheat are analyzed to further determine whether the air supply throttling element needs to be adjusted. In this embodiment, during the process of adjusting the air supply throttling element, the adjustment interval time is set to avoid frequent fluctuations in the system due to the opening adjustment of the throttling element, which is conducive to ensuring the operating stability of the heat pump system.

[0117] In an exemplary embodiment, the heat pump system control method further includes: if the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold and the economizer superheat is lower than the target economizer superheat, opening the first solenoid valve.

[0118] Specifically, the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold, indicating that the exhaust superheat is in the normal exhaust superheat range, and the economizer superheat is lower than the target economizer superheat, indicating that the refrigerant circulation amount obtained by diverting the liquid injection enthalpy increase branch is too much. In order to avoid the risk of liquid compression caused by bringing liquid back to the compressor medium pressure chamber from the liquid injection enthalpy increase branch, it is necessary to open the first solenoid valve to flow the separated liquid refrigerant back to the suction port of the compressor.

[0119] In an exemplary embodiment, the heat pump system control method also includes: when the operating mode of the heat pump system is a heating mode, the opening of the second throttling element is adjusted to a maximum opening threshold, and the opening of the first throttling element is controlled; when the operating mode of the heat pump system is a cooling mode, the opening of the first throttling element is adjusted to a maximum opening threshold, and the opening of the second throttling element is controlled.

[0120] Specifically, the controller can control the opening of the first throttling element / the second throttling element during the operation of the heat pump system according to the operating state of the compressor, so as to adjust the refrigerant circulation amount in the refrigerant circulation loop to ensure the stable operation of the system for cooling and heating. Among them, the data basis for controlling the opening of the first throttling element / the second throttling element is not unique, and it can be controlled according to the suction superheat of the compressor and the target suction superheat, or according to the exhaust superheat of the compressor and the target exhaust superheat, or according to the operating parameters of the indoor heat exchanger or the outdoor heat exchanger, or according to any combination of the above operating parameters, which can be selected according to technical requirements, as long as the refrigerant circulation amount in the refrigerant circulation loop can be adjusted to ensure the stable operation of the system for cooling and heating.

[0121] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0122] In a specific embodiment, Fig.11 and Fig.12 As shown, a heat pump system control method is provided, which is applied to Figure 7 Heat pump system shown.

[0123] Specifically, the heat pump system includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a first throttling element 4, an economizer 5 and an indoor heat exchanger 6 connected by pipelines to form a refrigerant circulation loop. It also includes a liquid injection enthalpy increase branch, so that the refrigerant diverted from the refrigerant circulation loop flows from the main path of the first throttling element 4 and the economizer 5 through the auxiliary path of the economizer 5 into the air supply port of the compressor 1, and the liquid injection enthalpy increase branch is also provided with an air supply throttling element 7. It also includes a first temperature sensor 8, a second temperature sensor 9 and a third temperature sensor 10, which are used to obtain the exhaust temperature of the compressor 1, the auxiliary path inlet temperature and the auxiliary path outlet temperature of the economizer 5, and a pressure sensor 11, which is used to obtain the exhaust pressure of the compressor 1. The liquid injection enthalpy increase branch is also provided with a gas-liquid separation element 12 and a first solenoid valve 13. The refrigerant flowing out through the auxiliary path of the economizer 5 enters the gas-liquid separation element 12, and the separated gaseous refrigerant is supplemented into the air supply port of the compressor 1, and the separated liquid refrigerant flows into the air intake port of the compressor 1 through the first solenoid valve 13. The heat pump system also includes: a liquid bypass branch, so that the refrigerant diverted from the refrigerant circulation loop flows into the air intake port of the compressor 1 from the main path between the indoor heat exchanger 6 and the economizer 5, and a second solenoid valve 14 is also provided on the liquid bypass branch. The heat pump system also includes: a second throttling element 15, located between the indoor heat exchanger 6 and the main path of the economizer 5, wherein the first throttling element 4 and the second throttling element 15 are both one-way throttling valves. The heat pump system also includes: an air bypass branch, so that the refrigerant diverted from the refrigerant circulation loop flows into the air intake port of the compressor 1 from the exhaust port of the compressor 1, and a third solenoid valve 16 is also provided on the air bypass branch.

[0124] Reference Fig.11 and Fig.12 After the heat pump system is turned on in cooling mode or heating mode, the exhaust pressure is first detected. If the exhaust pressure is greater than 3.8Mpa, open the solenoid valve 1 (the third solenoid valve 16) to bypass the gas to reduce the exhaust pressure. Further, when the operating frequency of the compressor 1 is greater than the preset operating frequency (A) and reaches the preset time (X), the exhaust temperature is judged. When the exhaust temperature is greater than the exhaust temperature threshold (100°C), open the solenoid valve 2 (the second solenoid valve 14) to bypass the liquid, and then open the auxiliary electronic expansion valve (air supply throttling element 7) to increase the enthalpy of the jet, reduce the exhaust temperature, and increase the enthalpy of the jet to increase the cooling and heating capacity. If the exhaust temperature is less than or equal to the exhaust temperature threshold (100°C), keep the solenoid valve 2 closed and still open the auxiliary electronic expansion valve to the minimum opening.

[0125] Then judge the exhaust superheat of the compressor. If the exhaust superheat is greater than the first exhaust superheat threshold (D, 40°C), the auxiliary electronic expansion valve is adjusted according to the economic superheat, but the auxiliary electronic expansion valve is only allowed to open wide, and the maximum value is the set maximum value. If the exhaust superheat is less than the second exhaust superheat threshold (C, 35°C), the auxiliary electronic expansion valve is adjusted according to the economic superheat and is only allowed to close down, and the minimum value is the set minimum value. If the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold, the auxiliary electronic expansion valve is freely adjusted according to the economic superheat.

[0126] Among them, the process of adjusting the opening of the auxiliary electronic expansion valve according to the economic superheat can be to first determine the difference between the current economic superheat and the target economic superheat. If the difference between the current economic superheat and the target economic superheat is ≤-1, the opening of the current auxiliary electronic expansion valve is reduced and the solenoid valve 3 (the first solenoid valve 13) is opened. If the difference between the current economic superheat and the target economic superheat is ≥1, the opening of the current auxiliary electronic expansion valve is increased. If -1≤the difference between the current economic superheat and the target economic superheat≤1, the opening of the current auxiliary electronic expansion valve is kept unchanged.

[0127] In this embodiment, in the heat pump system, by providing one-way main throttling elements at both ends of the economizer and cooperating with the air-supply throttling element, the compressor is supplemented with air to increase enthalpy, and at the same time, the second solenoid valve is turned on and off to spray liquid and air to the system, thereby reducing exhaust and improving cooling and heating capabilities. The exhaust superheat is combined with the economizer superheat to control the opening of the air-supply throttling element, thereby reducing exhaust and improving cooling and heating capabilities while ensuring the reliability of the compressor. The heat pump system provided in this application expands the scope of use of the system through combined control of air bypass, liquid bypass and jet enthalpy increase to meet the user's cooling and heating comfort needs.

[0128] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0129] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A heat pump system, characterized in that: The heat pump system comprises: The refrigerant circulation loop allows the refrigerant to circulate in a loop consisting of a compressor, a four-way valve, an outdoor heat exchanger, a first throttling element, an economizer and an indoor heat exchanger; The liquid injection enthalpy increase branch allows the refrigerant diverted from the refrigerant circulation circuit to flow from between the first throttling element and the main path of the economizer through the auxiliary path of the economizer into the air supply port of the compressor, and the liquid injection enthalpy increase branch is also provided with an air supply throttling element; A temperature sensing component, used to obtain the exhaust temperature of the compressor, the auxiliary circuit inlet temperature and the auxiliary circuit outlet temperature of the economizer; A pressure sensing element, used to obtain the exhaust pressure of the compressor; The controller is configured as: The exhaust superheat is obtained according to the exhaust temperature and the exhaust pressure, and an optional adjustment method for the opening of the air supply throttling element is determined according to the exhaust superheat, and the adjustment method at least includes increasing, decreasing and maintaining; the economizer superheat is obtained according to the auxiliary line inlet temperature and the auxiliary line outlet temperature, and a target adjustment method is determined from the optional adjustment methods based on the economizer superheat, and the opening of the air supply throttling element is controlled with the target adjustment method.

2. The heat pump system according to claim 1, characterized in that: The controller is further configured to: If the exhaust gas superheat is greater than a first exhaust gas superheat threshold, determining that the optional adjustment method for the opening of the air supplement throttling element includes increasing and maintaining; If the exhaust gas superheat is less than a second exhaust gas superheat threshold, determining that the optional adjustment method for the opening of the air supplement throttling element includes decreasing and maintaining; If the exhaust gas superheat is between the second exhaust gas superheat threshold and the first exhaust gas superheat threshold, determining that the optional adjustment method for the opening of the air supplement throttling element includes increasing, decreasing and maintaining; Wherein, the first exhaust gas superheat threshold is greater than the second exhaust gas superheat threshold.

3. The heat pump system according to claim 2, characterized in that: The controller is further configured to: Determining a current regulation mode based on a comparison result of the economizer superheat and a target economizer superheat; If the current adjustment mode belongs to the optional adjustment mode, determining the current adjustment mode as the target adjustment mode; Otherwise, the target adjustment mode is determined to be maintained.

4. The heat pump system according to claim 3, characterized in that: The controller is further configured to: If the economizer superheat meets the target economizer superheat, determining that the current adjustment mode is to maintain; If the economizer superheat exceeds the target economizer superheat, determining that the current adjustment mode is to increase; If the economizer superheat is lower than the target economizer superheat, it is determined that the current adjustment mode is to reduce.

5. The heat pump system according to claim 2, characterized in that: The liquid injection enthalpy increase branch is also provided with a gas-liquid separation element and a first solenoid valve. The refrigerant flowing out through the auxiliary path of the economizer enters the gas-liquid separation element, and the separated gaseous refrigerant is replenished into the air supply port of the compressor, and the separated liquid refrigerant flows into the air intake port of the compressor through the first solenoid valve. The controller is further configured to: If the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold, and the economizer superheat is lower than a target economizer superheat, the first solenoid valve is opened.

6. The heat pump system according to claim 1, characterized in that: The controller is further configured to: When the operating frequency of the compressor is greater than the preset operating frequency, recording a first time; When the first time exceeds a preset time length, the air supply throttling element is opened, and the opening degree of the air supply throttling element is adjusted to a minimum opening degree threshold.

7. The heat pump system according to claim 1, characterized in that: The heat pump system further comprises: A liquid bypass branch allows the refrigerant diverted from the refrigerant circulation circuit to flow into the suction port of the compressor from between the indoor heat exchanger and the economizer main circuit, and a second solenoid valve is also provided on the liquid bypass branch; The controller is further configured to: If the exhaust temperature is greater than the exhaust temperature threshold, the second solenoid valve is opened.

8. The heat pump system according to claim 1, characterized in that: The heat pump system further comprises: a second throttling element, located between the indoor heat exchanger and the main circuit of the economizer, wherein the first throttling element and the second throttling element are both one-way throttling valves; The controller is further configured to: When the operation mode of the heat pump system is a heating mode, controlling the opening degree of the first throttling element; When the operation mode of the heat pump system is a cooling mode, the opening degree of the second throttling element is controlled.

9. A heat pump system control method, applicable to the heat pump system according to any one of claims 1 to 8, wherein the method is executed by the controller, and is characterized in that: The method comprises: Obtain exhaust superheat according to exhaust temperature and exhaust pressure; Determine an optional adjustment method for the opening of the air supplement throttling element according to the exhaust gas superheat, the adjustment method at least including increasing, decreasing and maintaining; The economizer superheat is obtained according to the auxiliary line inlet temperature and the auxiliary line outlet temperature; A target regulation mode is determined from the optional regulation modes based on the economizer superheat, and the opening of the air supply throttling element is controlled by the target regulation mode.

10. The heat pump system control method according to claim 9, characterized in that: The method further comprises: If the exhaust gas superheat is greater than a first exhaust gas superheat threshold, determining that the optional adjustment method for the opening of the air supplement throttling element includes increasing and maintaining; If the exhaust gas superheat is less than a second exhaust gas superheat threshold, determining that the optional adjustment method for the opening of the air supplement throttling element includes decreasing and maintaining; If the exhaust gas superheat is between the second exhaust gas superheat threshold and the first exhaust gas superheat threshold, determining that the optional adjustment method for the opening of the air supplement throttling element includes increasing, decreasing and maintaining; Wherein, the first exhaust gas superheat threshold is greater than the second exhaust gas superheat threshold.

11. The heat pump system control method according to claim 10, characterized in that: The method further comprises: Determining a current regulation mode based on a comparison result of the economizer superheat and a target economizer superheat; If the current adjustment mode belongs to the optional adjustment mode, determining the current adjustment mode as the target adjustment mode; Otherwise, the target adjustment mode is determined to be maintained.

12. The heat pump system control method according to claim 10, characterized in that: The method further comprises: If the exhaust superheat is between the second exhaust superheat threshold and the first exhaust superheat threshold, and the economizer superheat is lower than a target economizer superheat, the first solenoid valve is opened.

13. The heat pump system control method according to claim 9, characterized in that: The method further comprises: When the operation mode of the heat pump system is a heating mode, controlling the opening degree of the first throttling element; When the operation mode of the heat pump system is the cooling mode, the opening degree of the second throttling element is controlled.

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