Heat pump air conditioning system

Abstract

The present invention provides a heat pump air conditioning system, wherein the refrigerant circuit includes a compressor, an air-side outdoor heat exchanger, a water-side outdoor heat exchanger, and an indoor heat exchanger. The indoor heat exchanger is connected to the air-side outdoor heat exchanger and the water-side outdoor heat exchanger via a liquid-side connecting pipe, an air-side pipeline, and a water-side pipeline, respectively. A detection unit is configured to infer flammable refrigerant leakage, and a control unit is configured to perform refrigerant recovery control and correct the opening of the air-side throttling device based on the temperature difference 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 temperature difference of the flammable refrigerant in the water-side pipeline and the air-side pipeline, so that the opening changes of both devices under refrigerant recovery control do not exceed a set range. The present invention can avoid the problem of premature liquid filling during the refrigerant recovery process, which may cause system shutdown and lead to recovery failure, and ensure complete and stable refrigerant recovery.

Description

Technical Field

[0001] The present 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 is a fluorohydrofluorocarbon refrigerant containing hydrogen, fluorine, and carbon, and is a non-flammable gas. Due to its relatively high potential to damage the ozone layer, R410A has been gradually replaced by R290 and R32. R290 is natural gas propane, an alkane refrigerant that contains only hydrogen and carbon, without fluorine. Therefore, its potential to damage the ozone layer is very low, making it a green refrigerant with less impact on the environment. R32 is a fluoroalkane refrigerant containing hydrogen, fluorine, and carbon. Its ozone depletion potential is lower, but still higher than R290. R290 and R32 have good refrigeration properties, such as high latent heat, which can provide efficient cooling or heating.

[0003] However, R290 is a flammable gas and the combustion properties of R32 are slightly worse than 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. To address this problem, some solutions have been proposed in the prior art, such as the technical solution disclosed in Chinese patent application (CN115289651A): "An air conditioner includes an indoor unit, an air outlet of which is provided with a refrigerant detection element, and a compressor having a refrigerant outlet and a refrigerant inlet; a high-pressure detection element is provided between a four-way valve and the refrigerant outlet of the compressor, and a low-pressure detection element is provided between the four-way valve and the refrigerant inlet of the compressor; an indoor heat exchanger is connected to the compressor via the four-way valve; an outdoor heat exchanger is connected to the compressor via the four-way valve, and a throttling device is provided between the outdoor heat exchanger and the indoor heat exchanger; a controller is configured to control the four-way valve in response to a leakage signal detected by the refrigerant detection element to operate the indoor heat exchanger as an evaporator; control the compressor to operate at a preset frequency within a preset recovery cycle, receive pressure signals from the high-pressure detection element and the low-pressure detection element, and control the opening of the throttling device within the preset recovery cycle."

[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 and failure of recovery. 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 a condenser to be filled with liquid prematurely during the recovery process, and the condensing capacity will suddenly drop, causing shutdown and resulting in recovery failure. The first aspect of this 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, and 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 infer 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 the control unit performs refrigerant recovery control, it 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, it calculates the 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, it 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 correspondingly 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 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; and 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 on the basis of the maximum opening, 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, 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; and 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 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.

[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 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 exhaust 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 working opening of the air-side throttling device based on the exhaust superheat.

[0025] The present invention maintains 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, thereby reducing safety risks to a minimum.

[0026] Other features and advantages of the present invention will become more apparent after reading the detailed description of the present invention in conjunction with the accompanying drawings. 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 is a brief introduction to 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 any creative labor.

[0028] Figure 1 A schematic structural diagram 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 performs refrigerant recovery control;

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

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

[0037] Figure 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] Figure 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] Figure 12 A schematic diagram of a refrigerant circuit before refrigerant recovery control is performed in a heat pump air conditioning system provided by one or more embodiments of the present application;

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

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

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

[0043] Figure 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] Figure 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] Figure 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] Figure 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] Figure 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] Figure 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] Figure 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 shutoff valve; 110. Gas-side shutoff 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 this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

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

[0053] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include one or more of such 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 expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

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

[0056] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0057] Figure 1 A schematic structural diagram of a heat pump air conditioning system provided by one or more embodiments of the present invention is shown; 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] Heat pump air conditioning system 1 is installed in buildings such as apartments, hotels, office buildings, and residences. Heat pump air conditioning system 1 is configured to selectively perform hot water supply and heating operations simultaneously, or hot water supply and cooling operations simultaneously; or independently perform cooling operations; or independently perform hot water supply operations.

[0059] Heat pump air conditioning system 1 incorporates a refrigeration cycle. The refrigeration cycle utilizes a compressor 101, a condenser, a throttling device, and an evaporator. The refrigeration cycle involves a series of processes, including compression, condensation, expansion, and evaporation, to cool or heat the indoor space.

[0060] In principle, low-temperature, low-pressure refrigerant enters 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, releasing heat into the surrounding environment through the condensation process.

[0061] The throttling device expands the high-temperature, 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 low-temperature, low-pressure refrigerant gas to the compressor 101. The evaporator achieves a cooling effect by utilizing the latent heat of evaporation of the refrigerant to exchange heat with the material to be cooled. Throughout this cycle, the heat pump air conditioning system 1 can regulate 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, or more indoor units can be arranged in the same manner as the indoor units shown in the figure.

[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 at its minimum opening, can nearly shut off the fluid passage in the liquid-side connecting pipe 127. The gas-side shutoff valve 110 can shut off the fluid passage in the gas-side connecting pipe 128 or, when at its minimum opening, can nearly shut 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. 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 portion of the refrigeration cycle that includes the compressor 101 and the air-side outdoor heat exchanger 102. The outdoor unit also includes a hot water supply portion. The hot water supply portion includes a water-side outdoor heat exchanger 113, which is coupled to the water supply branch and the water use branch (for example, using parallel pipes or sleeves) to heat the water in the water supply branch (from the water source) and store the heated water in a water tank, or directly guide the heated water to the water use area via the water use branch. The hot water supply portion also includes a water pump 114.

[0068] The outdoor unit can perform heating or cooling operations outdoors, providing energy to the indoor unit to increase or decrease the indoor temperature. The outdoor unit is also equipped with a gas-liquid separator 108, an outdoor fan 106, and a reversing valve (e.g., a four-way valve 124). A liquid storage tank may 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), in which 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 connected in sequence 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 connected in sequence 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] Compressor 101 is configured to draw in and compress refrigerant to a high-temperature, high-pressure state. The type of compressor 101 is not further limited herein and may include, for example, a reciprocating compressor 101, a screw compressor 101, or the like. The speed of compressor 101 is variably controlled by an inverter. There may be one or more compressors 101.

[0075] The air side outdoor heat exchanger 102 is configured to function 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 so that the refrigerant flowing in the air side outdoor heat exchanger 102 undergoes 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 function as a condenser during hot water supply operation. The water-side outdoor heat exchanger 113 can exchange heat with water flowing in the water supply branch and the water use branch, which are located near the water-side outdoor heat exchanger 113. An inlet water temperature sensor 119 is provided on the water supply branch, and an outlet water temperature sensor 120 is provided on the water use branch.

[0077] The air-side pipe 125 and the water-side pipe 126 are each 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 via the liquid-side connecting pipe 127 and the air-side pipe 125, and is connected to the water-side outdoor heat exchanger 113 via 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 refrigerant into gas and liquid and storing the separated refrigerant. The gas-liquid separator 108 can store excess refrigerant.

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

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

[0081] The indoor unit utilizes the energy generated by the outdoor unit to increase or decrease the indoor temperature to perform cooling or heating operations. The indoor unit includes indoor heat exchangers (105a, 105b) and indoor throttling devices (104a, 104b) connected in series. Indoor fans (107a, 107b) are disposed near the indoor heat exchangers (105a, 105b) to deliver heated or cooled air to the air-conditioned room. The indoor fans (107a, 107b) may be axial flow fans, cross flow fans, or other fans capable of achieving the same function.

[0082] The indoor heat exchangers (105a, 105b) function as condensers in heating mode and as evaporators in cooling mode. The refrigerant in the indoor heat exchangers exchanges heat with the air flowed by the indoor fan, causing the refrigerant to undergo 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 this 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 ducted air supply structure, an air supply structure embedded in the ceiling, etc. The air supply structure includes a shell, a return air port on the shell for sucking air, and an air supply port for sending the heat-exchanged air into the air-conditioned room.

[0085] The indoor unit can be equipped with a wired controller, remote control, or mobile control terminal to input set temperature, operation mode, display real-time temperature, system operation status, etc. The mobile control terminal can be a computer, tablet computer, smartphone, wearable device, etc.

[0086] The indoor unit houses the indoor control circuit. This circuit is housed in a well-sealed, heat-dissipating electrical enclosure. The indoor control circuit includes components such as a processor, a storage unit, input / output interfaces, and a communication interface. The processor can be a dedicated processor or a central processing unit (CPU). The processor can access the storage unit to execute instructions or applications stored therein to implement related functions. The storage unit can include volatile memory and / or non-volatile memory. The input / output interface can be connected to various sensors provided in the indoor unit to receive detection values ​​from the various sensors provided 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), which is used to detect the flammable refrigerant concentration in a 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 an air-conditioned room covered by air supply, as well as the installation space of the indoor unit and the interior of the housing; the liquid pipe temperature sensor (115a, 115b) and the gas pipe temperature sensor (116a, 116b) are also connected. The communication interface can support different wireless communication protocols, such as Wi-Fi, Bluetooth, etc.

[0087] The heat pump air conditioning system 1 further 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. When the flammable refrigerant concentration in a specified indoor space exceeds the concentration threshold, it is estimated that there is a flammable refrigerant leak. The control unit 13 is configured to execute 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 execute 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, by an outdoor control circuit, jointly by a communicatively connected indoor control circuit and an outdoor control circuit, or by a cloud server communicatively connected to the indoor control circuit and / or the outdoor control circuit.

[0089] Refrigerant recovery control utilizes the operation of compressor 101 to recover flammable refrigerant from the indoor unit to the outdoor side for further maintenance and processing, thereby isolating potential hazards in the outdoor environment, reducing the possibility of it approaching an ignition source, and avoiding fire and explosion accidents that endanger human life and property safety. Due to the different condensing capacities of the air-side outdoor heat exchanger 102 and the water-side outdoor heat exchanger 113, one outdoor heat exchanger may prematurely fill with liquid during the refrigerant recovery control process. "Filling with liquid" means that the refrigerant in the condenser fills the condenser in a liquid state, rather than evaporating or condensing under normal operating conditions. In this case, the pressure in the high-pressure section of the heat pump air conditioning system 1 will increase or even exceed the design range, and the compressor 101 will be subjected to an abnormal workload, causing the compressor 101 to shut down. However, at this time, the flammable refrigerant has not been completely recovered and still remains indoors. If there is leakage or damage in the system, 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 (e.g. Figure 3 As shown in step S101), 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 (as shown in step S101). Figure 3 As shown in step S102), 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 pipe 126 and the air side pipe 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 degree of the air side throttling device 103 and the opening degree 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, 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 (e.g. Figure 4 As shown in step S201 in the figure), the air side adjustment proportional coefficient (such as Figure 4 The air side adjustment proportional coefficient is the ratio of the first set constant to the temperature difference of the flammable refrigerant in the air side pipe 125 and the water side pipe 126. The controller uses the product of the air side adjustment proportional coefficient and the opening of the air side throttling device 103 in the current adjustment cycle as the opening of the next adjustment cycle (as shown in step S202). Figure 4 The opening degree of the next adjustment cycle is less than or equal to the opening degree of the current adjustment cycle.

[0095] That is, the formula is:

[0096] EVO(n)-EVO(n-1)≤0;

[0097] EVO(n)=EVO(n-1)×c1 / (T e -T rl );

[0098] Among them, 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 pipe 125 (ie, the pipe temperature of the air side pipe 125), T rl is the flammable refrigerant temperature of the water side pipe 126 (ie, the pipe temperature of the water side pipe 126), c1 is a first set constant, 2≤c1≤5. c1 / (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 (e.g. Figure 5 As shown in step S301), 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 pipe 126 and the air side pipe 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 (e.g. 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)×c2 / (T rl -T e );

[0103] Among them, EVw(n) is the opening degree of the water side throttling device 112 in the next adjustment cycle, EVw(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 pipe 125 (ie, the pipe temperature of the air side pipe 125), T rl is the flammable refrigerant temperature of the water side pipe 126 (ie, the pipe temperature of the water side pipe 126), c2 is the second set constant, 2≤c2≤5. c2 / (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 c1 and the second setting constant c2 are preferably 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 description of the calibration process for 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 Figure 9 A complete flammable refrigerant recovery control process is shown.

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

[0108] Refrigerant recovery control includes:

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

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

[0111] like Figure 6 As indicated by arrow F1, when the indoor units are performing cooling operation, the liquid-side shutoff valve 109 and the gas-side shutoff valve 110 remain open. Low-pressure gas refrigerant is drawn into the compressor 101. The refrigerant is compressed to a high-temperature, high-pressure state in the compressor 101 and then discharged from the compressor 101. The high-temperature, high-pressure refrigerant flows through the four-way valve 124 into the air-side outdoor heat exchanger 102. 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, becoming 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 into the indoor units is decompressed by the air-side throttle device 103 and the indoor throttle devices (104a, 104b), becoming low-pressure two-phase gas-liquid refrigerant or low-pressure liquid refrigerant. The refrigerant then flows into the indoor heat exchangers (105a, 105b).

[0112] The low-pressure refrigerant that has flowed into the indoor heat exchangers (105a, 105b) evaporates in the indoor heat exchangers (105a, 105b) and becomes low-pressure gas refrigerant, which then flows out of the indoor heat exchangers (105a, 105b). The low-pressure gas refrigerant that has flowed out of the indoor heat exchangers (105a, 105b) flows into the outdoor unit via the gas-side communication 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 then sucked back into the compressor 101.

[0113] The high-temperature and high-pressure refrigerant can simultaneously flow into the water-side outdoor heat exchanger 113, thereby achieving 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. Figure 18 As indicated by arrow F4, low-pressure gas refrigerant is drawn into compressor 101. The refrigerant is compressed to a high-temperature, high-pressure state in compressor 101 and discharged from compressor 101. It flows through four-way valve 124 and out of the outdoor unit via gas-side connecting pipe 128. The high-pressure gas refrigerant that has flowed out of the outdoor unit then flows into the indoor unit. The refrigerant that has flowed into the indoor unit flows into the indoor heat exchangers (105a, 105b). The high-pressure gas refrigerant is condensed in the indoor heat exchangers (105a, 105b) to become high-pressure liquid refrigerant, which then flows out of the indoor heat exchangers (105a, 105b).

[0115] The high-pressure liquid refrigerant from the indoor heat exchangers (105a, 105b) is reduced in pressure by the indoor throttle devices (104a, 104b) and the air-side throttle device 103, becoming a low-pressure two-phase gas-liquid refrigerant that flows out of the indoor unit via the liquid-side communication pipe 127. The low-pressure refrigerant then flows into the air-side outdoor heat exchanger 102, exchanges heat with the air introduced 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 passes through the four-way valve 124 and the gas-liquid separator 108, and is again sucked into the compressor 101.

[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, the air-side throttling device 103 is at the maximum opening, and 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, for example, 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 Figure 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 (as shown in FIG. Figure 10 As shown in step S404), the water side throttling device 112 is controlled to be at the maximum opening MAX (as shown in step S404). Figure 10 As shown in step S405), the control room throttling device is at the maximum opening (as shown in step S405). Figure 10 At the same time, the indoor fan speed is increased to high wind gear (MAX), the outdoor fan 106 speed is increased to high wind gear (MAX), and the water pump 114 speed is increased to high speed gear (MAX). Preferably, all speeds are increased to the upper limit 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 Figure 10 As shown in step S407), 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 pipe 126 and the air side pipe 125 (as shown in step S407). Figure 10 As shown in step S408 in the figure, the opening changes of the two under the refrigerant recovery control do not exceed the set range, and the refrigerant flow is 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 unit is evacuated, the refrigerant recovery is completed.

[0125] The estimated refrigerant pump down can be based on Figure 11 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 it meets the P s ≤bM pa ,like Figure 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 Figure 11 As shown in step S410.

[0128] The air side shut-off valve 110 is controlled to cut off the fluid passage in the air side communicating pipe 128. Figure 11 As shown in step S411.

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

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

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

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

[0133] Refrigerant recovery control includes:

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

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

[0136] When the indoor units are performing cooling operation, the liquid-side shutoff valve 109 and the gas-side shutoff valve 110 remain open. Low-pressure gas refrigerant is drawn into the compressor 101. The refrigerant is compressed to a high-temperature, high-pressure state in the compressor 101 and then discharged from the compressor 101. The high-temperature, high-pressure refrigerant flows through the four-way valve 124 into the air-side outdoor heat exchanger 102. 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, becoming high-pressure liquid refrigerant. The high-pressure liquid refrigerant then flows out of the outdoor unit through the liquid-side connecting pipe 127 and into the two indoor units. The refrigerant that has flowed into the indoor units is decompressed by the air-side throttling device 103 and the indoor throttling device, becoming low-pressure two-phase gas-liquid refrigerant or low-pressure liquid refrigerant. The refrigerant then 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, becoming low-pressure gas refrigerant and flowing 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 through 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 again sucked into the compressor 101.

[0138] The high-temperature and high-pressure refrigerant can simultaneously flow into the water-side outdoor heat exchanger 113, thereby achieving 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. Figure 18 As shown, low-pressure gas refrigerant is drawn into compressor 101. The refrigerant is compressed to a high-temperature, high-pressure state in compressor 101 and discharged from compressor 101. It flows through four-way valve 124 and out of the outdoor unit via gas-side connecting pipe 128. The high-pressure gas refrigerant that has flowed out of the outdoor unit then 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, becoming high-pressure liquid refrigerant, which then flows out of the indoor heat exchanger.

[0140] The high-pressure liquid refrigerant from the indoor heat exchanger is reduced in pressure by the indoor throttle device and the air-side throttle device 103, becoming a low-pressure two-phase gas-liquid refrigerant that flows out of the indoor unit via the liquid-side communication pipe 127. The low-pressure refrigerant then flows into the air-side outdoor heat exchanger 102, exchanges heat with the air introduced by the outdoor fan 106, and becomes a low-pressure gas refrigerant that flows out of the air-side outdoor heat exchanger 102. The refrigerant that has flowed out of the air-side outdoor heat exchanger 102 passes through the four-way valve 124 and the gas-liquid separator 108, and is then sucked back into the compressor 101.

[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, for example, a seconds, where a is a constant, 0≤a<90.

[0144] At this time, the refrigerant circuit is as follows Figure 12 shown.

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

[0146] like Figure 13 As shown, the air side throttling device 103 is further controlled to be in the working opening (such as Figure 16 As shown in step S504), the water side throttling device 112 is controlled to be in the working opening (as shown in step S504). Figure 16 As shown in step S505), the control indoor throttling device is at the maximum opening MAX (as shown in step S506). Figure 16 At the same time, the indoor fan speed is increased to high wind gear (MAX), the outdoor fan 106 speed is increased to high wind gear (MAX), and the water pump 114 speed is increased to high speed gear (MAX), preferably all increased to the upper limit value to improve 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 the temperature of the flammable refrigerant in the air side pipe 125 and the water side pipe 126 (such as Figure 16 As shown in step S507), 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 pipe 126 and the air side pipe 125 (as shown in step S507). Figure 16 (as shown in step S508 in the figure), so that the opening changes of both under the refrigerant recovery control do not exceed the set amplitude range.

[0148] That is, when executing 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 describes how to generate the working opening: Figure 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 (as shown in FIG. Figure 19As shown in step S601), the working opening of the water side throttling device 112 is generated according to the outlet subcooling degree of the water side outdoor heat exchanger 113 (as shown in step S601). Figure 19 The working opening of the air side throttling device 103 is generated according to the outlet subcooling degree of the air side outdoor heat exchanger 102 (as shown in step S602). Figure 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 pipe 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 pipe 125 temperature and the saturation temperature corresponding to the exhaust pressure.

[0151] like Figure 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 (as shown in FIG. Figure 20 As shown in step S701), the working opening of the water side throttling device 112 is generated according to the outlet subcooling degree of the water side outdoor heat exchanger 113 (as shown in step S701). Figure 20 As shown in step S702), the operating opening of the air side throttling device 103 is generated according to the exhaust superheat (as shown in step S703). Figure 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 this field and will not be further described here.

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

[0156] The estimated refrigerant pump down can be based on Figure 17 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 it meets the P s ≤bM pa ,like Figure 17As 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 Figure 17 As shown in step S510.

[0159] The air side shut-off valve 110 is controlled to cut off the fluid passage in the air side communicating pipe 128. Figure 17 As shown in step S511.

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

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

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

[0163] like Figure 21 As shown, when the outdoor unit operates in emergency control mode, the liquid-side shutoff valve 109 and the gas-side shutoff valve 110 remain closed. Low-pressure gas refrigerant is drawn into the compressor 101. The refrigerant is compressed to a high-temperature, high-pressure state in the compressor 101 and discharged from the compressor 101. The high-temperature, 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 undergoes heat exchange with water in the water supply and water use branches, becoming high-pressure liquid refrigerant. The high-pressure liquid refrigerant then flows out of the water-side outdoor heat exchanger 113 via the water-side pipe 126 and into the air-side outdoor heat exchanger 102. The refrigerant that has flowed into the air-side outdoor heat exchanger 102 is decompressed by the air-side throttling device 103, becoming low-pressure two-phase gas-liquid refrigerant or low-pressure liquid refrigerant. It then flows through the four-way valve 124 and the gas-liquid separator 108 and is drawn back into the compressor 101.

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

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

[0166] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection 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 by: 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 refrigerant recovery control, the control unit calculates an air-side adjustment proportional coefficient based on a temperature difference of the flammable refrigerant in the air-side pipeline and the water-side pipeline, the air-side adjustment proportional coefficient being 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 degree of the air-side throttling device in the current adjustment cycle as the opening degree 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 refrigerant recovery control, the control unit calculates a water-side adjustment proportional coefficient based on a temperature difference of the flammable refrigerant in the water-side pipeline and the air-side pipeline, the water-side adjustment proportional coefficient being 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 shut-off valve; Also includes: A gas-side connecting pipe, wherein the gas-side connecting pipe is provided with a gas-side shut-off valve; 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 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 the gas-side connecting pipe is provided with a gas-side shut-off valve; 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 an operating 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 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 exhaust 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 connected to the air-side outdoor heat exchanger via an air-side pipeline and connected to the water-side outdoor heat exchanger via a water-side pipeline; a detection unit configured to detect whether the flammable refrigerant leaks 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 by: 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; The control unit, when executing refrigerant recovery control, 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 changes in the openings of the two devices under refrigerant recovery control do not exceed a set 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 inferring the emergency operating opening of the air-side throttling device based on the exhaust superheat.

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