Heat pump air conditioning system

Abstract

The invention provides a heat pump air conditioning system, a refrigerant loop comprises a compressor, an air side outdoor heat exchanger, a water side outdoor heat exchanger and an indoor heat exchanger, and the indoor heat exchanger is connected with the air side outdoor heat exchanger and the water side outdoor heat exchanger through a liquid side communication piping, an air side pipeline and a water side pipeline respectively; wherein the detection part is used for presuming flammable refrigerant leakage, and the control part is configured to execute refrigerant recovery control and correct the opening degree of the air side throttling device based on the difference value between the flammable refrigerant temperature in the air side pipeline and the flammable refrigerant temperature in the water side pipeline. And the opening degree of the water side throttling device is corrected based on the difference value of the temperatures of the flammable refrigerants in the water side pipeline and the air side pipeline, so that the opening degree changes of the flammable refrigerants in the water side pipeline and the air side pipeline under refrigerant recovery control do not exceed the set amplitude range. According to the invention, the problem of recovery failure caused by system shutdown due to premature filling in the refrigerant recovery process can be avoided, so that the refrigerant is completely and stably recovered.

Description

Technical Field

[0001] The invention relates to the technical field of air conditioning, and in particular to a heat pump air conditioning system. Background Art

[0002] Traditional air conditioning systems use R410A refrigerant. R410A refrigerant is a fluorinated hydrofluorocarbon refrigerant containing hydrogen, fluorine and carbon, and is a non-flammable gas. Due to the relatively high potential for R410A to damage the ozone layer, it has been gradually replaced by R290 and R32. R290 is natural gas propane, an alkane refrigerant that only contains hydrogen and carbon, without fluorine, so it has a very low potential for damaging the ozone layer. It is a green refrigerant with less impact on the environment, while R32 is a fluorinated alkane refrigerant containing hydrogen, fluorine and carbon. It has a lower potential for ozone depletion, but it is still higher than R290. R290 and R32 have good refrigeration properties, such as high latent heat, and can provide efficient cooling or heating.

[0003] However, R290 is a flammable gas and the combustion properties of R32 are slightly worse than those of R290. However, both require special safety precautions during use and storage. In particular, if they leak into the room and reach a certain concentration during use, there is a risk of explosion. In view of this problem, some solutions have been proposed in the prior art, such as the technical solution disclosed in the Chinese patent application (CN115289651A): "The air conditioner includes an indoor unit, whose air outlet is provided with a refrigerant detection component, and a refrigerant outlet and a refrigerant inlet are formed on the compressor; a high-pressure detection component is provided between the four-way valve and the refrigerant outlet of the compressor, and a low-pressure detection component is formed between the four-way valve and the refrigerant inlet of the compressor; the indoor heat exchanger is connected to the compressor through the four-way valve; the outdoor heat exchanger is connected to the compressor through the four-way valve, and a throttling device is provided between the outdoor heat exchanger and the indoor heat exchanger; the controller is configured to control the four-way valve to make the indoor heat exchanger work as an evaporator in response to a leakage signal detected by the refrigerant detection component; the compressor is controlled to work at a preset frequency within a preset recovery cycle, the pressure signals of the high-pressure detection component and the low-pressure detection component are received, and the opening of the throttling device within the preset recovery cycle is controlled."

[0004] The above-mentioned comparative documents disclose traditional split-type air conditioners, in which the refrigerant capacity is relatively small. For multi-split products, due to the long online pipelines, the large number of indoor units, and the existence of multiple condensers with different condensing capacities, if the recovery process is only adjusted by the throttling device described in the comparative documents, it is easy for a condenser to be filled with liquid prematurely, resulting in a sudden drop in condensing capacity or even shutdown, resulting in recovery failure. Summary of the invention

[0005] For air-conditioning systems with long online pipelines, a large number of indoor units and multiple condensers with different condensing capacities, it is easy for one condenser to be filled with liquid prematurely during the recovery process, and the condensing capacity may suddenly drop, causing shutdown and resulting in recovery failure. The first aspect of the present application designs and provides a heat pump air-conditioning system.

[0006] The heat pump air conditioning system includes a refrigerant circuit for circulating a flammable refrigerant, and the refrigerant circuit includes a compressor, an air-side outdoor heat exchanger, a water-side outdoor heat exchanger and an indoor heat exchanger; wherein the compressor is used to compress and discharge the flammable refrigerant, the air-side outdoor heat exchanger is used to allow the flammable refrigerant discharged from the compressor to exchange heat with outdoor air, the water-side outdoor heat exchanger is used to allow the flammable refrigerant discharged from the compressor to exchange heat with water, and the indoor heat exchanger is connected to the air-side outdoor heat exchanger through a liquid-side connecting pipe and an air-side pipeline, and is connected to the water-side outdoor heat exchanger through a liquid-side connecting pipe and a water-side pipeline.

[0007] In one or more embodiments of the present application, a detection unit is further included; the detection unit is configured to estimate whether there is leakage of the flammable refrigerant in the space where the indoor heat exchanger is located.

[0008] In one or more embodiments of the present application, a control unit is further included; the control unit is configured to execute refrigerant recovery control when the detection unit estimates that the flammable refrigerant is leaking in the space where the indoor heat exchanger is located.

[0009] In one or more embodiments of the present application, an air side throttling device is provided on the air side pipeline, and a water side throttling device is provided on the water side pipeline.

[0010] In one or more embodiments of the present application, when executing refrigerant recovery control, the control unit also corrects the opening of the air side throttling device based on the difference in temperature of the flammable refrigerant in the air side pipeline and the water side pipeline, and corrects the opening of the water side throttling device based on the difference in temperature of the flammable refrigerant in the water side pipeline and the air side pipeline, so that the opening changes of both under refrigerant recovery control do not exceed the set amplitude range.

[0011] In one or more embodiments of the present application, when the control unit performs refrigerant recovery control, the control unit calculates an air side adjustment proportional coefficient based on the temperature difference of the flammable refrigerant in the air side pipeline and the water side pipeline, and the air side adjustment proportional coefficient is the ratio of a first set constant to the temperature difference of the flammable refrigerant in the air side pipeline and the water side pipeline; and the product of the air side adjustment proportional coefficient and the opening of the air side throttling device in the current adjustment cycle is used as the opening of the next adjustment cycle; the opening of the next adjustment cycle is less than or equal to the opening of the current adjustment cycle.

[0012] In one or more embodiments of the present application, when the control unit performs refrigerant recovery control, the control unit calculates a water side adjustment proportional coefficient based on the temperature difference of the flammable refrigerant in the water side pipeline and the air side pipeline, and the water side adjustment proportional coefficient is the ratio of a second set constant to the temperature difference of the flammable refrigerant in the water side pipeline and the air side pipeline; and the product of the water side adjustment proportional coefficient and the opening of the water side throttling device in the current adjustment cycle is used as the opening of the next adjustment cycle; the opening of the next adjustment cycle is less than or equal to the opening of the current adjustment cycle.

[0013] In one or more embodiments of the present application, a liquid-side shutoff valve is provided on the liquid-side connecting pipe; and a gas-side shutoff valve is also provided on the gas-side connecting pipe of the heat pump air-conditioning system.

[0014] In one or more embodiments of the present application, a plurality of indoor heat exchangers are provided, and each indoor heat exchanger is provided with an indoor throttling device.

[0015] In one or more embodiments of the present application, the control unit is configured to execute refrigerant recovery control when the detection unit estimates that the flammable refrigerant has leaked in the space where any one of the indoor heat exchangers is located.

[0016] In one or more embodiments of the present application, the refrigerant recovery control includes: configuring the indoor heat exchanger as an evaporator; controlling the liquid side shut-off valve to cut off the fluid passage in the liquid side connecting piping; controlling the air side throttling device to be at the maximum opening; controlling the water side throttling device to be at the maximum opening; controlling the indoor throttling device to be at the maximum opening.

[0017] In one or more embodiments of the present application, the control unit is configured to correct the opening of the air side throttling device based on the difference in temperature of the flammable refrigerant in the air side pipeline and the water side pipeline, and correct the opening of the water side throttling device based on the difference in temperature of the flammable refrigerant in the water side pipeline and the air side pipeline, on the basis of the maximum opening, so that the opening changes of both under refrigerant recovery control do not exceed the set amplitude range.

[0018] In one or more embodiments of the present application, when the pressure on the suction side of the compressor does not exceed the warning condition, the control unit terminates the refrigerant recovery control, controls the gas side shut-off valve to cut off the fluid passage in the gas side connecting pipe, and controls the indoor throttling device to be at the minimum opening.

[0019] In one or more embodiments of the present application, the refrigerant recovery control includes: configuring the indoor heat exchanger as an evaporator; controlling the liquid side shut-off valve to cut off the liquid side connecting pipe; controlling the air side throttling device to be at an operating opening; controlling the water side throttling device to be at an operating opening; controlling the indoor throttling device to be at a maximum opening.

[0020] In one or more embodiments of the present application, the control unit is configured to correct the opening of the air side throttling device based on the difference in temperature of the flammable refrigerant in the air side pipeline and the water side pipeline, and correct the opening of the water side throttling device based on the difference in temperature of the flammable refrigerant in the water side pipeline and the air side pipeline, on the basis of the working opening, so that the opening changes of both under refrigerant recovery control do not exceed the set amplitude range.

[0021] In one or more embodiments of the present application, when the air side outdoor heat exchanger is configured as a condenser and the water side outdoor heat exchanger is configured as a condenser, the working opening of the water side throttling device is generated according to the outlet subcooling of the water side outdoor heat exchanger, and the working opening of the air side throttling device is generated according to the outlet subcooling of the air side outdoor heat exchanger.

[0022] In one or more embodiments of the present application, when the air side outdoor heat exchanger is configured as an evaporator and the water side outdoor heat exchanger is configured as a condenser, the working opening of the water side throttling device is generated according to the outlet subcooling of the water side outdoor heat exchanger, and the working opening of the air side throttling device is generated according to the exhaust gas superheat.

[0023] In one or more embodiments of the present application, when the pressure on the suction side of the compressor does not exceed the warning condition, the control unit terminates the refrigerant recovery control, controls the gas side shut-off valve to cut off the fluid passage in the gas side connecting pipe, and controls the indoor throttling device to be at the minimum opening.

[0024] In one or more embodiments of the present application, the control unit may execute emergency control after terminating the refrigerant recovery control, and the emergency control includes: configuring the water side outdoor heat exchanger as a condenser, the water side throttling device operating at the maximum opening, and estimating the emergency operating opening of the air side throttling device based on the exhaust superheat.

[0025] The present invention maintains the refrigerant recovery control, the opening degree of the air side throttling device and the opening degree of the water side throttling device are similar, the liquid levels in the air side outdoor heat exchanger and the water side outdoor heat exchanger rise at a similar speed and are maintained at a similar level, thereby giving full play to the storage capacity of the two outdoor heat exchangers. The design capacity of the two outdoor heat exchangers is also large enough to ensure that the flammable refrigerant can be stably, fully and completely recovered, reducing the safety risk to a minimum.

[0026] After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become more clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 A schematic diagram of the structure of a heat pump air conditioning system provided by one or more embodiments of the present application;

[0029] Figure 2 A schematic diagram of a refrigerant circuit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0030] Figure 3 A flow chart of a control unit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0031] Figure 4 A flow chart of a control unit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0032] Figure 5 A flow chart of a control unit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0033] Figure 6 A schematic diagram of a refrigerant circuit before the heat pump air conditioning system provided in one or more embodiments of the present application executes refrigerant recovery control;.

[0034] Figure 7 A schematic diagram of a refrigerant circuit when a heat pump air conditioning system provided by one or more embodiments of the present application performs refrigerant recovery control;

[0035] Figure 8 A schematic diagram of a refrigerant circuit when a heat pump air conditioning system provided by one or more embodiments of the present application performs refrigerant recovery control;

[0036] Fig. 9 A schematic diagram of a refrigerant circuit after the heat pump air conditioning system provided by one or more embodiments of the present application performs refrigerant recovery control;

[0037] Fig.10 A flow chart of a control unit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0038] Fig.11A flow chart of a control unit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0039] Fig.12 A schematic diagram of a refrigerant circuit before the heat pump air conditioning system provided by one or more embodiments of the present application performs refrigerant recovery control;

[0040] Fig.13 A schematic diagram of a refrigerant circuit when a heat pump air conditioning system provided by one or more embodiments of the present application performs refrigerant recovery control;

[0041] Fig.14 A schematic diagram of a refrigerant circuit when a heat pump air conditioning system provided by one or more embodiments of the present application performs refrigerant recovery control;

[0042] Fig.15 A schematic diagram of a refrigerant circuit after the heat pump air conditioning system provided by one or more embodiments of the present application performs refrigerant recovery control;

[0043] Fig.16 A flow chart of a control unit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0044] Fig.17 A flow chart of a control unit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0045] Fig.18 A schematic diagram of a refrigerant circuit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0046] Fig.19 A flow chart of a control unit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0047] Fig. 20 A flow chart of a control unit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0048] Fig.21 A schematic diagram of a refrigerant circuit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0049] Fig. 22 A flow chart of a control unit in a heat pump air conditioning system provided by one or more embodiments of the present application;

[0050] In the figure: 1, heat pump air conditioning system; 11a, designated indoor space; 11b, designated indoor space; 100, refrigerant circuit; 12, detection unit; 13, control unit; 101, compressor; 102, air side outdoor heat exchanger; 103, air side throttling device; 104a, indoor throttling device; 104b, indoor throttling device; 105a, indoor heat exchanger; 105b, indoor heat exchanger; 106, outdoor fan; 107a, indoor fan; 107b, indoor fan; 108, gas-liquid separator; 109, liquid side shut-off valve; 110, gas side shut-off valve; 111a, flammable refrigerant concentration sensor; 111b, flammable refrigerant concentration sensor ; 112, water side throttling device; 113, water side outdoor heat exchanger; 114, water pump; 115a, liquid pipe temperature sensor; 115b, liquid pipe temperature sensor; 116a, gas pipe temperature sensor; 116b, gas pipe temperature sensor; 117, air side pipeline temperature sensor; 118, water side pipeline temperature sensor; 119, water inlet temperature sensor; 120, water outlet temperature sensor, 121, compressor exhaust temperature sensor; 122, compressor exhaust pressure sensor; 123, compressor suction pressure sensor; 124, four-way valve; 125, air side pipeline; 126, water side pipeline; 127, liquid side connecting pipe; 128, gas side connecting pipe. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0052] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0053] The terms "first", "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0054] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] In the present invention, unless otherwise clearly stipulated and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0056] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0057] Figure 1 A schematic diagram showing the structure of a heat pump air conditioning system provided by one or more embodiments of the present invention; Figure 2 An example of a refrigerant circuit formed by a heat pump air conditioning system according to an embodiment of the present invention is shown.

[0058] The heat pump air conditioning system 1 is installed in buildings such as apartments, hotels, office buildings, and residences. The heat pump air conditioning system 1 is configured to selectively perform hot water supply operation and heating operation simultaneously, or perform hot water supply operation and cooling operation simultaneously; or perform cooling operation independently; or perform hot water supply operation independently.

[0059] A refrigeration cycle is integrated in the heat pump air conditioning system 1. A compressor 101, a condenser, a throttling device and an evaporator are used in the refrigeration cycle. The refrigeration cycle includes a series of processes involving compression, condensation, expansion and evaporation to cool or heat the indoor space.

[0060] From a principle perspective, low-temperature, low-pressure refrigerant enters the compressor 101, which compresses it into high-temperature, high-pressure refrigerant gas and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process.

[0061] The throttling device expands the high-temperature and high-pressure liquid refrigerant condensed in the condenser into a low-pressure liquid refrigerant. The evaporator evaporates the refrigerant expanded in the throttling device and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor 101. The evaporator can achieve a refrigeration effect by utilizing the latent heat of evaporation of the refrigerant to exchange heat with the material to be cooled. In the entire cycle, the heat pump air conditioning system 1 can adjust the temperature of the indoor space.

[0062] The heat pump air conditioning system 1 includes an outdoor unit and at least one indoor unit connected to each other. Figure 1 and Figure 2 Only two indoor units are shown in the figure, but in the present application, the number of indoor units is not particularly limited. Only one indoor unit can be arranged in one heat pump air conditioning system 1 in the same manner as the indoor units shown in the figure, or more indoor units can be arranged.

[0063] The indoor unit and the outdoor unit are connected by a liquid-side communication pipe 127 and a gas-side communication pipe 128. The liquid-side communication pipe 127 and the gas-side communication pipe 128 are used to allow the refrigerant to flow so that the refrigerant can form a refrigerant circuit 100 and circulate therein.

[0064] In one or more embodiments of the present application, a liquid-side shutoff valve 109 is provided on the liquid-side connecting pipe 127, and a gas-side shutoff valve 110 is provided on the gas-side connecting pipe 128. The liquid-side shutoff valve 109 can shut off the fluid passage in the liquid-side connecting pipe 127 or, when the opening is minimum, is close to shutting off the fluid passage in the liquid-side connecting pipe 127, and the gas-side shutoff valve 110 can shut off the fluid passage in the gas-side connecting pipe 128 or, when the opening is minimum, is close to shutting off the fluid passage in the gas-side connecting pipe 128.

[0065] The refrigerant flowing in the heat pump air conditioning system 1 is a flammable refrigerant, and the flammable refrigerant is R290 or R32 refrigerant with better environmental performance, or it can be other flammable refrigerants that meet industry standards.

[0066] The basic structure and function of the outdoor unit are described below. When the same system architecture is used, in the heat pump air conditioning system 1, the number of outdoor units can be expanded to multiple and operated in a group manner.

[0067] In one or more embodiments of the present application, the outdoor unit of the heat pump air conditioning system 1 refers to the part of the refrigeration cycle including the compressor 101 and the air-side outdoor heat exchanger 102, and the outdoor unit also includes a hot water supply part. The hot water supply part includes a water-side outdoor heat exchanger 113, and the water-side outdoor heat exchanger 113 is coupled to the water supply branch and the water use branch (for example, in the form of parallel pipes or sleeves), so that the water in the water supply branch (from the water source) can be heated, and the heated water can be stored in a water tank, or directly guided to the water use area via the water use branch after adding the heated water. The hot water supply part also includes a water pump 114.

[0068] The outdoor unit can perform heating operation or cooling operation on the outdoor side to provide the indoor unit with energy for increasing the indoor temperature or reducing the indoor temperature. The outdoor unit is also provided with a gas-liquid separator 108, an outdoor fan 106 and a reversing valve (such as a four-way valve 124); and a liquid storage tank can also be provided in the outdoor unit.

[0069] Under heating operation, the outdoor unit can form a refrigerant circuit 100 for heating operation (hereinafter referred to as a heating cycle), wherein the air side pipeline 125 (the air side pipeline 125 is provided with an air side throttling device 103), the air side outdoor heat exchanger 102, the four-way valve 124 (for example, the passage between the E port and the S port), the gas-liquid separator 108, the compressor 101 and the four-way valve 124 (for example, the passage between the D port and the C port) are connected in sequence from the liquid side connecting pipe 127 to the gas side connecting pipe 128.

[0070] Under refrigeration operation, the outdoor unit can form a refrigerant circuit 100 for refrigeration operation (hereinafter referred to as a refrigeration cycle), wherein a four-way valve 124 (for example, the passage between port C and port S), a gas-liquid separator 108, a compressor 101, a four-way valve 124 (for example, the passage between port D and port E), an air-side outdoor heat exchanger 102, and an air-side pipeline 125 (an air-side throttling device 103 is provided on the air-side pipeline 125) are sequentially connected from the gas-side connecting pipe 128 to the liquid-side connecting pipe 127.

[0071] The air side throttling device 103 is configured to reduce the pressure of the refrigerant and expand it. The opening degree of the air side throttling device 103 is adjustable. In the present application, the air side throttling device 103 is implemented by an electronic expansion valve.

[0072] Under hot water supply operation, the outdoor unit can form a refrigerant circuit 100 for preparing hot water (hereinafter referred to as a hot water cycle), which is sequentially connected to a compressor 101, a water side outdoor heat exchanger 113, a water side pipeline 126 (on which a water side throttling device 112 is provided), a gas-liquid separator 108 and a compressor 101.

[0073] The water-side throttling device 112 is configured to reduce the pressure of the refrigerant and expand it. The opening degree of the water-side throttling device 112 is adjustable. In the present application, the water-side throttling device 112 is implemented by an electronic expansion valve.

[0074] The compressor 101 is configured to suck in and compress the refrigerant into a high-temperature and high-pressure state. The type of the compressor 101 is not further limited herein, and may be, for example, a reciprocating compressor 101, a screw compressor 101, etc. The speed of the compressor 101 is variably controlled by a frequency converter. The number of compressors 101 may be one or more.

[0075] The air side outdoor heat exchanger 102 is configured to be used as a condenser in cooling operation and as an evaporator in heating operation. The air side outdoor heat exchanger 102 can perform heat exchange with the air guided by the outdoor fan 106 to cause the refrigerant flowing in the air side outdoor heat exchanger 102 to undergo a phase change (condensation or evaporation). The speed of the outdoor fan 106 can be controlled to change the flow rate of the air heat exchanged with the air side outdoor heat exchanger 102 by adjusting the speed. The outdoor fan 106 can be an axial flow fan, a cross flow fan or other optional fan forms. The outdoor fan 106 is arranged near the air side outdoor heat exchanger 102.

[0076] The water-side outdoor heat exchanger 113 is configured to be used as a condenser under hot water supply operation, and the water-side outdoor heat exchanger 113 can perform heat exchange with water flowing in the water supply branch and the water use branch, and the water supply branch and the water use branch are arranged near the water-side outdoor heat exchanger 113. An inlet water temperature sensor 119 is arranged on the water supply branch, and an outlet water temperature sensor 120 is arranged on the water use branch.

[0077] The air side pipe 125 and the water side pipe 126 are respectively connected to the liquid side connecting pipe 127, and the air side pipe 125 and the water side pipe 126 are connected in parallel. That is, the indoor heat exchanger is connected to the air side outdoor heat exchanger 102 through the liquid side connecting pipe 127 and the air side pipe 125, and is connected to the water side outdoor heat exchanger 113 through the liquid side connecting pipe 127 and the water side pipe 126.

[0078] The gas-liquid separator 108 is provided on the suction side of the compressor 101 and is a shell-shaped component for separating the gas and liquid of the refrigerant and storing the separated refrigerant. The gas-liquid separator 108 can store excess refrigerant.

[0079] An outdoor control circuit is provided in the outdoor unit. The outdoor control circuit is provided in an electrical box with good sealing performance and heat dissipation function. The outdoor control circuit includes components such as a processor, a storage unit, an input / output interface, and a communication interface. The processor may be a dedicated processor, a central processing unit (CPU), etc. The processor may access the storage unit to execute instructions or applications stored in the storage unit to implement related functions. The storage unit may include a volatile memory and / or a non-volatile memory. The input / output interface may be connected to various sensors provided in the outdoor unit for communication to receive detection values ​​of various sensors provided in the outdoor unit, including but not limited to a compressor exhaust temperature sensor 121, a compressor suction pressure sensor 123, a compressor exhaust pressure sensor 122, an air side pipeline temperature sensor 117 (specifically described in detail below), a water side pipeline temperature sensor 118 (specifically described in detail below), etc. The input / output interface can also be connected to the inverter, compressor 101, outdoor fan 106, four-way valve 124, air side throttling device 103, water side throttling device 112 and other devices to output the control instructions generated by the processor to them. The communication interface can support different wireless communication protocols, such as Wi-Fi, Bluetooth, near field communication, NB-loT, etc., to communicate with other electronic devices, including but not limited to cloud servers, computers (host computers), smart phones, tablet computers, PDAs, intelligent control tools, wearable devices, and vehicle-mounted devices, etc.

[0080] The structure and function of the indoor unit are described below, taking one of the indoor units as an example. The following description is also applicable to other indoor units.

[0081] The indoor unit performs cooling operation or heating operation using the energy generated by the outdoor unit to increase the indoor temperature or reduce the indoor temperature. The indoor unit includes an indoor heat exchanger (105a, 105b) and an indoor throttling device (104a, 104b) connected in series. The indoor fan (107a, 107b) is arranged near the indoor heat exchanger (105a, 105b) to deliver heated or cooled air to the air-conditioned room. The indoor fan (107a, 107b) can be an axial flow fan or a cross flow fan, or other fans that can achieve the same function.

[0082] The indoor heat exchanger (105a, 105b) is used as a condenser in heating operation and as an evaporator in cooling operation. The refrigerant in the indoor heat exchanger exchanges heat with the air guided by the indoor fan, so that the refrigerant therein undergoes a phase change (condensation or evaporation).

[0083] The indoor throttling device (104a, 104b) is configured to reduce the pressure of the refrigerant and expand it. The opening degree of the indoor throttling device (104a, 104b) is adjustable. In the present application, the indoor throttling device (104a, 104b) is implemented by an electronic expansion valve.

[0084] The indoor unit can adopt a wall-mounted air supply structure, a floor-standing air supply structure, a duct-type air supply structure, an air supply structure embedded in the ceiling, etc. The air supply structure includes a shell, a return air port for sucking air in the shell, and an air supply port for sending the heat-exchanged air into the air-conditioned room.

[0085] The indoor unit can be matched with a wired controller, a remote controller or a mobile control terminal for inputting set temperature, operation mode, displaying real-time temperature, system operation status, etc. The mobile control terminal can be a computer, a tablet computer, a smart phone, a wearable device, etc.

[0086] An indoor control circuit is provided in the indoor unit. The indoor control circuit is provided in an electrical box with good sealing performance and heat dissipation function. The indoor control circuit includes components such as a processor, a storage unit, an input / output interface, and a communication interface. The processor may be a dedicated processor, a central processing unit (CPU), etc. The processor may access the storage unit to execute instructions or applications stored in the storage unit to implement related functions. The storage unit may include a volatile memory and / or a non-volatile memory. The input / output interface can be connected to various sensors arranged in the indoor unit for communication to receive the detection values ​​of various sensors arranged in the indoor unit. For example, the input / output port in the indoor control circuit is connected to the flammable refrigerant concentration sensor (111a, 111b), and the flammable refrigerant concentration sensor (111a, 111b) is used to detect the flammable refrigerant concentration in the designated indoor space (11a, 11b). The designated indoor space (11a, 11b) is, for example, the space where the indoor heat exchanger is located. The space where the indoor heat exchanger is located includes but is not limited to the air-conditioned room covered by the air supply, and also includes the installation space of the indoor unit and the inside of the shell; it is also connected to the liquid pipe temperature sensor (115a, 115b) and the gas pipe temperature sensor (116a, 116b). The communication interface can support different wireless communication protocols, such as Wi-Fi, Bluetooth, etc.

[0087] The heat pump air conditioning system 1 also includes: a detection unit 12 and a control unit 13. The detection unit 12 is configured to estimate whether there is a flammable refrigerant leak in the space where the indoor heat exchanger is located, for example, based on a pre-set flammable refrigerant concentration threshold, and when the flammable refrigerant concentration in the designated indoor space exceeds the concentration threshold, it is estimated that there is a flammable refrigerant leak. The control unit 13 is configured to perform refrigerant recovery control when the detection unit 12 estimates that there is a flammable refrigerant leak in the space where the indoor heat exchanger is located. When there are multiple outdoor units, the control unit 13 is configured to perform refrigerant recovery control when the detection unit 12 estimates that there is a flammable refrigerant leak in the space where any indoor heat exchanger is located.

[0088] In one or more embodiments of the present application, the functions of the control unit 13 may be performed by an indoor control circuit, or by an outdoor control circuit, or by a communicatively connected indoor control circuit and outdoor control circuit jointly, or by a cloud server communicatively connected to the indoor control circuit and / or the outdoor control circuit.

[0089] Refrigerant recovery control is to utilize the operation of the compressor 101 to recover the flammable refrigerant in the indoor unit to the outdoor side to wait for further maintenance and processing, thereby isolating potential dangers in the outdoor environment, reducing the possibility of it being close to the ignition source, avoiding safety accidents such as fire and explosion, and endangering the safety of life and property. Due to the different condensing capacities of the air-side outdoor heat exchanger 102 and the water-side outdoor heat exchanger 113, an outdoor heat exchanger may be filled with liquid prematurely during the refrigerant recovery control process. "Full liquid" means that the refrigerant in the condenser fills the condenser in the liquid phase instead of evaporating or condensing under its normal working conditions. At this time, the pressure of the high-pressure part of the heat pump air-conditioning system 1 will increase or even exceed the design range, and the compressor 101 will be subjected to abnormal work load, causing the compressor 101 to shut down; but at this time, the flammable refrigerant has not been completely recovered, and still remains on the indoor side, and the system is leaking or damaged, and the flammable refrigerant may further leak into the surrounding environment, causing the entire recovery control to fail.

[0090] To solve this problem, in one or more embodiments of the present application, the control unit 13 performs refrigerant recovery control (such as Figure 3 As shown in step S101), the opening degree of the air side throttling device 103 is corrected based on the difference in temperature of the flammable refrigerant in the air side pipeline 125 and the water side pipeline 126 (as shown in step S101). Figure 3 The opening of the water side throttling device 112 is corrected based on the difference in temperature of the flammable refrigerant in the water side pipeline 126 and the air side pipeline 125 (as shown in step S102). Figure 3As shown in step S103 in the figure), so that the opening changes of both under the refrigerant recovery control do not exceed the set amplitude range (such as Figure 3 (as shown in step S104).

[0091] That is, under the refrigerant recovery control, the opening of the air side throttling device 103 and the opening of the water side throttling device 112 are similar, and the liquid levels in the air side outdoor heat exchanger 102 and the water side outdoor heat exchanger 113 rise at a similar speed and remain at a similar level, thereby giving full play to the storage capacity of the two outdoor heat exchangers. The design capacity of the two outdoor heat exchangers is also large enough to ensure that the flammable refrigerant can be stably, fully and completely recovered, thereby reducing the safety risk to a minimum.

[0092] The set amplitude range can be a constant, which is written into the storage unit in advance by the technician. The purpose of the set amplitude is to ensure that under the refrigerant recovery control, the opening of the air side throttling device 103 and the opening of the water side throttling device 112 are always close. It is related to the design capacity of the heat pump air-conditioning system 1, and its value is not further restricted here.

[0093] In one or more embodiments of the present application, along the direction of the refrigeration cycle, the water side pipe temperature sensor 118 is arranged downstream of the outlet of the water side outdoor heat exchanger 113, and the air side pipe temperature sensor 117 is arranged downstream of the outlet of the air side outdoor heat exchanger 102.

[0094] In one or more embodiments of the present application, the control unit 13 performs refrigerant recovery control (such as Figure 4 As shown in step S201 in the figure), the air side adjustment proportional coefficient (such as Figure 4 The air side regulation proportional coefficient is the ratio of the first set constant to the temperature difference of the flammable refrigerant in the air side pipeline 125 and the water side pipeline 126. The controller uses the product of the air side regulation proportional coefficient and the opening of the air side throttling device 103 in the current regulation cycle as the opening of the next regulation cycle (e.g. Figure 4 The opening of the next adjustment cycle is less than or equal to the opening of the current adjustment cycle.

[0095] That is, the formula is:

[0096] EVO(n)-EVO(n-1)≤0;

[0097] EVO(n)=EVO(n-1)×c 1 / (T e -T rl );

[0098] Wherein, EVO(n) is the opening degree of the air side throttling device 103 in the next adjustment cycle, EVO(n-1) is the opening degree of the air side throttling device 103 in the current adjustment cycle, T e is the flammable refrigerant temperature of the air side pipeline 125 (ie, the pipe temperature of the air side pipeline 125), T rl is the flammable refrigerant temperature of the water side pipeline 126 (ie, the pipe temperature of the water side pipeline 126), c 1 is the first setting constant, 2≤c 1 ≤5.c 1 / (T e -T rl ) is the air side adjustment proportional coefficient.

[0099] In one or more embodiments of the present application, the control unit 13 performs refrigerant recovery control (such as Figure 5 The water side adjustment proportional coefficient (such as Figure 5 The water side regulation proportional coefficient is the ratio of the second set constant to the temperature difference of the flammable refrigerant in the water side pipeline 126 and the air side pipeline 125. The controller uses the product of the water side regulation proportional coefficient and the opening of the water side throttling device 112 in the current regulation cycle as the opening of the next regulation cycle (such as Figure 5 The opening degree of the next adjustment cycle is less than or equal to the opening degree of the current adjustment cycle.

[0100] That is, the formula is:

[0101] EVw(n)-EVw(n-1)≤0;

[0102] EVw(n)=EVw(n-1)×c 2 / (T rl -T e );

[0103] Wherein, EVw(n) is the opening degree of the water side throttling device 112 in the next regulation cycle, EVw(n-1) is the opening degree of the air side throttling device 103 in the current regulation cycle, T e is the flammable refrigerant temperature of the air side pipeline 125 (ie, the pipe temperature of the air side pipeline 125), T rl is the flammable refrigerant temperature of the water side pipeline 126 (ie, the pipe temperature of the water side pipeline 126), c 2 is the second setting constant, 2≤c 2 ≤5.c 2 / (T rl -T e) is the water side regulation proportional coefficient.

[0104] In one or more embodiments of the present application, the first setting constant c 1 and the second setting constant c 2 Preferably they are equal.

[0105] Since the working fluid is more sensitive to temperature changes in the heat pump air conditioning system 1, the temperature as a parameter has a relatively fast response speed and more stable test conditions. Using temperature to calculate the air side adjustment proportional coefficient and the water side adjustment proportional coefficient can generate accurate opening correction values ​​more quickly, ensure the recovery speed, and avoid large leakage and low recovery speed.

[0106] The following is a further detailed introduction to the correction process of adjusting the air side throttling device 103 and the water side throttling device 112 to ensure that the two values ​​are close, in conjunction with the entire process of flammable refrigerant recovery control. Figure 6 , Figure 7 , Figure 8 and Fig. 9 A complete flammable refrigerant recovery control process is shown.

[0107] The control unit 13 is configured to execute refrigerant recovery control (such as Fig.10 (as shown in step S401).

[0108] Refrigerant recovery control includes:

[0109] Configure the indoor heat exchanger as an evaporator (such as Fig.10 (as shown in step S402).

[0110] Before performing the refrigerant recovery control, the indoor unit may perform a heating operation or a cooling operation.

[0111] like Figure 6As shown by the middle arrow F1, when the indoor unit performs cooling operation, the liquid side shutoff valve 109 and the gas side shutoff valve 110 remain in the conducting state. Low-pressure gas refrigerant is sucked into the compressor 101. The refrigerant is compressed into a high-temperature and high-pressure state in the compressor 101 and discharged from the compressor 101. The high-temperature and high-pressure refrigerant flows into the air side outdoor heat exchanger 102 through the four-way valve 124. The high-pressure gas refrigerant that has flowed into the air side outdoor heat exchanger 102 exchanges heat with the air guided by the outdoor fan 106 and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows out of the outdoor unit through the liquid side connecting pipe 127 and then flows to the two indoor units. The refrigerant that has flowed to the indoor unit is decompressed by the air side throttling device 103 and the indoor throttling device (104a, 104b), thereby becoming a low-pressure two-phase gas-liquid refrigerant or a low-pressure liquid refrigerant. Then, the refrigerant flows into the indoor heat exchanger (105a, 105b).

[0112] The low-pressure refrigerant that has flowed into the indoor heat exchanger (105a, 105b) evaporates in the indoor heat exchanger (105a, 105b) to become a low-pressure gas refrigerant, and flows out of the indoor heat exchanger (105a, 105b). The low-pressure gas refrigerant that has flowed out of the indoor heat exchanger (105a, 105b) flows into the outdoor unit via the gas-side connecting pipe 128. The low-pressure gas refrigerant that has flowed into the outdoor unit flows through the four-way valve 124 and the gas-liquid separator 108, and is sucked into the compressor 101 again.

[0113] The high-temperature and high-pressure refrigerant can flow into the water-side outdoor heat exchanger 113 at the same time, thereby realizing hot water supply.

[0114] When the indoor unit performs heating operation, the liquid-side shutoff valve 109 and the gas-side shutoff valve 110 remain in the conducting state. Fig.18 As shown by the middle arrow F4, low-pressure gas refrigerant is sucked into the compressor 101. The refrigerant is compressed into a high-temperature and high-pressure state in the compressor 101 and discharged from the compressor 101, flows through the four-way valve 124 and flows out of the outdoor unit through the gas-side connecting pipe 128. Then, the high-pressure gas refrigerant that has flowed out of the outdoor unit flows into the indoor unit. The refrigerant that has flowed into the indoor unit flows into the indoor heat exchanger (105a, 105b). The high-pressure gas refrigerant is condensed in the indoor heat exchanger (105a, 105b) and becomes a high-pressure liquid refrigerant, and flows out of the indoor heat exchanger (105a, 105b).

[0115] The high-pressure liquid refrigerant from the indoor heat exchanger (105a, 105b) is decompressed by the indoor throttling device (104a, 104b) and the air-side throttling device 103, thereby becoming a low-pressure two-phase gas-liquid refrigerant that flows out of the indoor unit through the liquid-side connecting pipe 127. Then, the low-pressure refrigerant flows into the air-side outdoor heat exchanger 102, exchanges heat with the air guided from the outdoor fan 106, becomes a low-pressure gas refrigerant, and flows out of the air-side outdoor heat exchanger 102. The refrigerant that has flowed out of the air-side outdoor heat exchanger 102 flows through the four-way valve 124 and the gas-liquid separator 108, and is sucked into the compressor 101 again.

[0116] The high-temperature and high-pressure refrigerant can also flow into the water-side outdoor heat exchanger 113 at the same time, thereby realizing hot water supply.

[0117] If only cooling operation is performed, the water side throttling device 112 is in a closed state, and the air side throttling device 103 is at the maximum opening. The system exhaust superheat is controlled by the indoor throttling device (104a, 104b), that is, the system exhaust superheat (the difference between the compressor exhaust temperature and the saturation temperature corresponding to the compressor exhaust pressure) is maintained at the target exhaust superheat by adjusting the indoor throttling device (104a, 104b).

[0118] When the refrigerant recovery control is executed, if the indoor unit performs cooling operation, no additional control is performed and the indoor heat exchanger is configured as an evaporator.

[0119] When executing refrigerant recovery control, if the indoor unit performs heating operation, it is first switched to cooling operation, the indoor heat exchanger is configured as an evaporator, and the cooling operation is maintained for a period of time, such as a seconds, where a is a constant, 0≤a<90.

[0120] Further control the liquid side shutoff valve 109 to cut off the liquid side connecting pipe 127 (such as Fig.10 (as shown in step S403).

[0121] like Figure 7 As shown, the air side throttling device 103 is further controlled to be at the maximum opening MAX (such as Fig.10 As shown in step S404), the water side throttling device 112 is controlled to be at the maximum opening MAX (such as Fig.10 As shown in step S405), the control room throttling device is at the maximum opening (such as Fig.10 At the same time, the indoor fan speed is increased to the high wind gear (MAX), the outdoor fan 106 speed is increased to the high wind gear (MAX), and the water pump 114 is increased to the high speed gear (MAX), preferably all increased to the upper limit value to increase the recovery speed. The refrigerant flow during recovery is as follows: Figure 7 As shown by the arrow F2.

[0122] Further, the indoor throttling device is kept at the maximum opening (MAX), and based on the maximum opening, the opening of the air side throttling device 103 is corrected based on the difference in temperature of the flammable refrigerant in the air side pipe 125 and the water side pipe 126 (such as Fig.10 The opening of the water side throttling device 112 is corrected based on the difference in temperature of the flammable refrigerant in the water side pipeline 126 and the air side pipeline 125 (as shown in step S407). Fig.10 As shown in step S408 in the figure, the opening changes of both under the refrigerant recovery control do not exceed the set range, and the refrigerant flows as follows Figure 8 shown.

[0123] That is, when executing refrigerant recovery control, EVO(n-1) and EVw(n-1) are both at the maximum opening, and are gradually corrected based on the air side adjustment proportional coefficient and the water side adjustment proportional coefficient within multiple adjustment cycles.

[0124] When the refrigerant in the indoor machine is evacuated, the refrigerant recovery is completed.

[0125] The estimated refrigerant pump down can be based on Fig.11 The multiple steps shown:

[0126] Determine whether the pressure on the suction side of the compressor 101 does not exceed the warning condition, that is, whether the pressure on the suction side of the compressor 101 satisfies the P s ≤bM pa ,like Fig.11 As shown in step S409, b is a constant, b≤0.2.

[0127] If the pressure on the suction side of the compressor 101 does not exceed the warning condition, the refrigerant recovery is terminated, such as Fig.11 As shown in step S410.

[0128] The air side shutoff valve 110 is controlled to cut off the fluid passage in the air side connecting pipe 128. Fig.11 As shown in step S411.

[0129] The throttling device in the control room is at the minimum opening, such as Fig.11 As shown in step S412.

[0130] The refrigeration cycle after recovery is as follows Fig. 9 shown.

[0131] Fig.12 , Fig.13 , Fig.14 and Fig.15 Another complete flammable refrigerant recovery control process is shown.

[0132] The control unit 13 is configured to execute refrigerant recovery control (such as Fig.16 (as shown in step S501).

[0133] Refrigerant recovery control includes:

[0134] Configure the indoor heat exchanger as an evaporator (such as Fig.16 (as shown in step S502).

[0135] Before performing the refrigerant recovery control, the indoor unit may perform a heating operation or a cooling operation.

[0136] When the indoor unit performs cooling operation, the liquid side shutoff valve 109 and the gas side shutoff valve 110 remain in the conducting state. Low-pressure gas refrigerant is sucked into the compressor 101. The refrigerant is compressed into a high-temperature and high-pressure state in the compressor 101 and discharged from the compressor 101. The high-temperature and high-pressure refrigerant flows into the air side outdoor heat exchanger 102 via the four-way valve 124. The high-pressure gas refrigerant that has flowed into the air side outdoor heat exchanger 102 undergoes heat exchange with the air guided by the indoor fan and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows out of the outdoor unit via the liquid side connecting pipe 127 and then flows to the two indoor units. The refrigerant that has flowed to the indoor unit is decompressed by the air side throttling device 103 and the indoor throttling device, thereby becoming a low-pressure two-phase gas-liquid refrigerant or a low-pressure liquid refrigerant. Then, the refrigerant flows into the indoor heat exchanger.

[0137] The low-pressure refrigerant that has flowed into the indoor heat exchanger evaporates in the indoor heat exchanger to become a low-pressure gas refrigerant and flows out of the indoor heat exchanger. The low-pressure gas refrigerant that has flowed out of the indoor heat exchanger flows into the outdoor unit via the gas-side connecting pipe 128. The low-pressure gas refrigerant that has flowed into the outdoor unit flows through the four-way valve 124 and the gas-liquid separator 108, and is sucked into the compressor 101 again.

[0138] The high-temperature and high-pressure refrigerant can flow into the water-side outdoor heat exchanger 113 at the same time, thereby realizing hot water supply.

[0139] When the indoor unit performs heating operation, the liquid-side shutoff valve 109 and the gas-side shutoff valve 110 remain in the conducting state. Fig.18 As shown, low-pressure gas refrigerant is sucked into the compressor 101. The refrigerant is compressed into a high-temperature and high-pressure state in the compressor 101 and discharged from the compressor 101, flows through the four-way valve 124 and flows out of the outdoor unit through the gas-side connecting pipe 128. Then, the high-pressure gas refrigerant that has flowed out of the outdoor unit flows into the indoor unit. The refrigerant that has flowed into the indoor unit flows into the indoor heat exchanger. The high-pressure gas refrigerant is condensed in the indoor heat exchanger to become a high-pressure liquid refrigerant, and flows out of the indoor heat exchanger.

[0140] The high-pressure liquid refrigerant from the indoor heat exchanger is decompressed by the indoor throttling device and the air-side throttling device 103, thereby becoming a low-pressure two-phase gas-liquid refrigerant that flows out of the indoor unit through the liquid-side connecting pipe 127. Then, the low-pressure refrigerant flows into the air-side outdoor heat exchanger 102, exchanges heat with the air guided from the outdoor fan 106, becomes a low-pressure gas refrigerant, and flows out of the air-side outdoor heat exchanger 102. The refrigerant that has flowed out of the air-side outdoor heat exchanger 102 flows through the four-way valve 124 and the gas-liquid separator 108, and is sucked into the compressor 101 again.

[0141] The high-temperature and high-pressure refrigerant can also flow into the water-side outdoor heat exchanger 113 at the same time, thereby realizing hot water supply.

[0142] When the refrigerant recovery control is executed, if the indoor unit performs cooling operation, no additional control is performed and the indoor heat exchanger is configured as an evaporator.

[0143] When executing refrigerant recovery control, if the indoor unit performs heating operation, it is first switched to cooling operation, the indoor heat exchanger is configured as an evaporator, and the cooling operation is maintained for a period of time, such as a seconds, where a is a constant, 0≤a<90.

[0144] At this time, the refrigerant circuit is Fig.12 shown.

[0145] Further control the liquid side shutoff valve 109 to cut off the liquid side connecting pipe 127 (such as Fig.16 (as shown in step S503).

[0146] like Fig.13 As shown, the air side throttling device 103 is further controlled to be in a working opening (such as Fig.16 As shown in step S504), the water side throttling device 112 is controlled to be in a working opening (such as Fig.16 The control room throttling device is at the maximum opening MAX (as shown in step S505). Fig.16 At the same time, the indoor fan speed is increased to a high wind gear (MAX), the outdoor fan 106 speed is increased to a high wind gear (MAX), and the water pump 114 speed is increased to a high speed gear (MAX), preferably all increased to the upper limit value, so as to increase the recovery speed.

[0147] Further, the indoor throttling device is kept at the maximum opening (MAX), and based on the working opening, the opening of the air side throttling device 103 is corrected based on the difference in temperature of the flammable refrigerant in the air side pipe 125 and the water side pipe 126 (such as Fig.16 The opening of the water side throttling device 112 is corrected based on the difference in temperature of the flammable refrigerant in the water side pipeline 126 and the air side pipeline 125 (as shown in step S507). Fig.16As shown in step S508 in the figure), the opening changes of both under the refrigerant recovery control do not exceed the set amplitude range.

[0148] That is, when executing the refrigerant recovery control, EVO(n-1) and EVw(n-1) are both working openings, and are gradually corrected based on the air side adjustment proportional coefficient and the water side adjustment proportional coefficient within multiple adjustment cycles.

[0149] The following is an introduction to the generation method of working opening, such as Fig.19 As shown, when the air side outdoor heat exchanger 102 is configured as a condenser and the water side outdoor heat exchanger 113 is configured as a condenser (such as Fig.19 As shown in step S601), the working opening degree of the water side throttling device 112 is generated according to the outlet subcooling degree of the water side outdoor heat exchanger 113 (such as Fig.19 As shown in step S602), the working opening degree of the air side throttling device 103 is generated according to the outlet subcooling degree of the air side outdoor heat exchanger 102 (such as Fig.19 (as shown in step S603).

[0150] The outlet subcooling degree of the water-side outdoor heat exchanger 113 can be calculated by the difference between the water-side pipeline 126 temperature and the saturation temperature corresponding to the exhaust pressure, and the outlet subcooling degree of the air-side outdoor heat exchanger 102 can be calculated by the difference between the air-side pipeline 125 temperature and the saturation temperature corresponding to the exhaust pressure.

[0151] like Fig. 20 As shown, when the air outdoor heat exchanger is configured as an evaporator and the water side outdoor heat exchanger 113 is configured as a condenser (such as Fig. 20 As shown in step S701), the working opening degree of the water side throttling device 112 is generated according to the outlet subcooling degree of the water side outdoor heat exchanger 113 (such as Fig. 20 As shown in step S702), the operating opening of the air side throttling device 103 is generated according to the exhaust gas superheat (such as Fig. 20 (as shown in step S703).

[0152] The outlet subcooling degree of the water side outdoor heat exchanger 113 can be calculated by the difference between the water side pipeline 126 temperature and the saturation temperature corresponding to the exhaust pressure, and the exhaust superheat degree can be calculated by the difference between the exhaust temperature of the compressor 101 and the saturation temperature corresponding to the exhaust pressure of the compressor 101.

[0153] When the water-side throttling device 112 and the air-side throttling device 103 are operating at the working opening (for example, cooling operation + hot water supply, heating operation + hot water supply), the indoor throttling device controls the subcooling degree of the indoor unit, that is, the opening of the indoor throttling device is generated according to the difference between the liquid pipe temperature sensor and the detection value and the saturation temperature corresponding to the exhaust pressure of the compressor 101.

[0154] Adjusting the number of steps of the electronic expansion valve according to the target value of superheat to eliminate superheat deviation is a common technical means in the art and will not be further introduced here.

[0155] When the refrigerant in the indoor machine is evacuated, the refrigerant recovery is completed.

[0156] The estimated refrigerant pump down can be based on Fig.17 The multiple steps shown:

[0157] Determine whether the pressure on the suction side of the compressor 101 does not exceed the warning condition, that is, whether the pressure on the suction side of the compressor 101 satisfies the P s ≤bM pa ,like Fig.17 As shown in step S509.

[0158] If the pressure on the suction side of the compressor 101 does not exceed the warning condition, the refrigerant recovery is terminated, such as Fig.17 As shown in step S510.

[0159] The air side shutoff valve 110 is controlled to cut off the fluid passage in the air side connecting pipe 128. Fig.17 As shown in step S511.

[0160] The throttling device in the control room is at the minimum opening, such as Fig.17 As shown in step S512.

[0161] The refrigeration cycle after recovery is as follows Fig.15 shown.

[0162] like Fig. 22 As shown in step S806, after the recovery is completed, the heat pump air conditioning system 1 may also optionally have an emergency control mode. The emergency control mode includes configuring the water-side outdoor heat exchanger 113 as a condenser, the water-side throttling device 112 to operate at the maximum opening, and estimating the emergency operating opening of the air-side throttling device 103 according to the exhaust gas superheat.

[0163] like Fig.21As shown, when the outdoor unit is running in the emergency control mode, the liquid side shutoff valve 109 and the gas side shutoff valve 110 remain in the closed state. Low-pressure gas refrigerant is sucked into the compressor 101. The refrigerant is compressed into a high-temperature and high-pressure state in the compressor 101 and discharged from the compressor 101. The high-temperature and high-pressure refrigerant flows into the water-side outdoor heat exchanger 113. The high-pressure gas refrigerant that has flowed into the water-side outdoor heat exchanger 113 exchanges heat with the water in the water supply branch and the water use branch to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows out of the water-side outdoor heat exchanger 113 through the water-side pipeline 126 and then flows to the air-side outdoor heat exchanger 102. The refrigerant that has flowed to the air-side outdoor heat exchanger 102 is decompressed by the air-side throttling device 103, thereby becoming a low-pressure two-phase gas-liquid refrigerant or a low-pressure liquid refrigerant; it flows through the four-way valve 124 and the gas-liquid separator 108, and is sucked into the compressor 101 again.

[0164] In cold weather conditions, emergency control mode can keep the indoor environment within acceptable range until maintenance personnel can deal with the leak.

[0165] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0166] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A heat pump air conditioning system, comprising: A refrigerant circuit, configured to circulate a flammable refrigerant, comprising: a compressor that compresses and discharges the flammable refrigerant; an air-side outdoor heat exchanger for exchanging heat between the flammable refrigerant discharged from the compressor and outdoor air; a water-side outdoor heat exchanger for exchanging heat between the flammable refrigerant discharged from the compressor and water; and An indoor heat exchanger connected to the air-side outdoor heat exchanger via a liquid-side connecting pipe and an air-side pipeline, and connected to the water-side outdoor heat exchanger via a liquid-side connecting pipe and a water-side pipeline; a detection unit configured to estimate whether the flammable refrigerant is leaking in the space where the indoor heat exchanger is located; and a control unit configured to execute refrigerant recovery control when the detection unit estimates that the flammable refrigerant has leaked in the space where the indoor heat exchanger is located; It is characterized in that The air side pipeline is provided with an air side throttling device, and the water side pipeline is provided with a water side throttling device; When executing refrigerant recovery control, the control unit also corrects the opening of the air side throttling device based on the difference in temperature of the flammable refrigerant in the air side pipeline and the water side pipeline, and corrects the opening of the water side throttling device based on the difference in temperature of the flammable refrigerant in the water side pipeline and the air side pipeline, so that the opening changes of both under refrigerant recovery control do not exceed the set amplitude range.

2. The heat pump air conditioning system according to claim 1, characterized in that: When executing the refrigerant recovery control, the control unit calculates an air side adjustment proportional coefficient based on the temperature difference of the flammable refrigerant in the air side pipeline and the water side pipeline, wherein the air side adjustment proportional coefficient is a ratio of a first set constant to the temperature difference of the flammable refrigerant in the air side pipeline and the water side pipeline; and uses the product of the air side adjustment proportional coefficient and the opening of the air side throttling device in the current adjustment cycle as the opening of the next adjustment cycle; The opening degree of the next adjustment cycle is less than or equal to the opening degree of the current adjustment cycle.

3. The heat pump air conditioning system according to claim 1, characterized in that: When executing the refrigerant recovery control, the control unit calculates a water side adjustment proportional coefficient based on the temperature difference of the flammable refrigerant in the water side pipeline and the air side pipeline, wherein the water side adjustment proportional coefficient is a ratio of a second set constant to the temperature difference of the flammable refrigerant in the water side pipeline and the air side pipeline; and uses the product of the water side adjustment proportional coefficient and the opening of the water side throttling device in the current adjustment cycle as the opening of the next adjustment cycle; The opening degree of the next adjustment cycle is less than or equal to the opening degree of the current adjustment cycle.

4. The heat pump air conditioning system according to any one of claims 1 to 3, characterized in that: The liquid side connecting pipe is provided with a liquid side cut-off valve; Also includes: A gas-side connecting pipe, wherein a gas-side shutoff valve is provided on the gas-side connecting pipe; The indoor heat exchangers are provided with a plurality of units, and each of the indoor heat exchangers is provided with an indoor throttling device; The control unit is configured to execute refrigerant recovery control when the detection unit estimates that the flammable refrigerant has leaked in the space where any one of the indoor heat exchangers is located, and the refrigerant recovery control includes: Configure the indoor heat exchanger as an evaporator; Controlling the liquid-side shutoff valve to cut off the fluid passage in the liquid-side communicating pipe; Controlling the air side throttling device to be at the maximum opening; Controlling the water side throttling device to be at the maximum opening; Controlling the indoor throttling device to be at the maximum opening; On the basis of the maximum opening, the opening of the air side throttling device is corrected based on the difference in temperature of the flammable refrigerant in the air side pipeline and the water side pipeline, and the opening of the water side throttling device is corrected based on the difference in temperature of the flammable refrigerant in the water side pipeline and the air side pipeline, so that the opening changes of both under refrigerant recovery control do not exceed the set amplitude range.

5. The heat pump air conditioning system according to claim 4, characterized in that: When the pressure on the suction side of the compressor does not exceed the warning condition, the control unit terminates the refrigerant recovery control, controls the gas side shut-off valve to cut off the fluid passage in the gas side connecting pipe, and controls the indoor throttling device to be at the minimum opening.

6. The heat pump air conditioning system according to any one of claims 1 to 3, characterized in that: Also includes: A liquid side connecting pipe, wherein the liquid side connecting pipe is provided with a liquid side shutoff valve; A gas-side connecting pipe, wherein a gas-side shutoff valve is provided on the gas-side connecting pipe; There are multiple indoor heat exchangers, and each indoor heat exchanger is correspondingly provided with an indoor throttling device; The control unit is configured to execute refrigerant recovery control when the detection unit estimates that the flammable refrigerant has leaked in the space where any one of the indoor heat exchangers is located, and the refrigerant recovery control includes: Configure the indoor heat exchanger as an evaporator; Controlling the liquid-side shutoff valve to cut off the liquid-side communicating pipe; Controlling the air side throttling device to be at a working opening; Controlling the water side throttling device to be at a working opening; Controlling the indoor throttling device to be at the maximum opening; On the basis of the working opening, the opening of the air side throttling device is corrected based on the difference in temperature of the flammable refrigerant in the air side pipeline and the water side pipeline, and the opening of the water side throttling device is corrected based on the difference in temperature of the flammable refrigerant in the water side pipeline and the air side pipeline, so that the opening changes of both under refrigerant recovery control do not exceed the set amplitude range.

7. The heat pump air conditioning system according to claim 6, characterized in that: When the air side outdoor heat exchanger is configured as a condenser and the water side outdoor heat exchanger is configured as a condenser, the operating opening of the water side throttling device is generated according to the outlet subcooling of the water side outdoor heat exchanger, and the operating opening of the air side throttling device is generated according to the outlet subcooling of the air side outdoor heat exchanger.

8. The heat pump air conditioning system according to claim 6, characterized in that: When the air side outdoor heat exchanger is configured as an evaporator and the water side outdoor heat exchanger is configured as a condenser, the working opening of the water side throttling device is generated according to the outlet subcooling of the water side outdoor heat exchanger, and the working opening of the air side throttling device is generated according to the exhaust gas superheat.

9. The heat pump air conditioning system according to claim 6, characterized in that: When the pressure on the suction side of the compressor does not exceed the warning condition, the control unit terminates the refrigerant recovery control, controls the gas side shut-off valve to cut off the fluid passage in the gas side connecting pipe, and controls the indoor throttling device to be at the minimum opening.

10. A heat pump air conditioning system, comprising: A refrigerant circuit, configured to circulate a flammable refrigerant, comprising: a compressor that compresses and discharges the flammable refrigerant; an air-side outdoor heat exchanger for exchanging heat between the flammable refrigerant discharged from the compressor and outdoor air; a water-side outdoor heat exchanger for exchanging heat between the flammable refrigerant discharged from the compressor and water; and An indoor heat exchanger, which is connected to the air-side outdoor heat exchanger through an air-side pipeline and connected to the water-side outdoor heat exchanger through a water-side pipeline; a detection unit configured to detect whether there is leakage of the flammable refrigerant in the space where the indoor heat exchanger is located; and The control unit is configured to execute refrigerant recovery control when the detection unit estimates that the flammable refrigerant has leaked in the space where the indoor heat exchanger is located; It is characterized in that The air side pipeline is provided with an air side throttling device, and the water side pipeline is provided with a water side throttling device; When executing the refrigerant recovery control, the control unit further corrects the opening of the air side throttling device based on the difference in temperature of the flammable refrigerant in the air side pipeline and the water side pipeline, and corrects the opening of the water side throttling device based on the difference in temperature of the flammable refrigerant in the water side pipeline and the air side pipeline, so that the opening changes of both under the refrigerant recovery control do not exceed the set amplitude range; After terminating the refrigerant recovery control, the control unit can execute emergency control, which includes: configuring the water-side outdoor heat exchanger as a condenser, operating the water-side throttling device at the maximum opening, and estimating the emergency operating opening of the air-side throttling device based on the exhaust superheat.

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