CN119665345B

CN119665345B - Heat pump air conditioning system

Info

Publication number: CN119665345B
Application number: CN202311212706.XA
Authority: CN
Inventors: 刘心怡; 李伟; 邵宗臣; 辛电波
Original assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Current assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Priority date: 2023-09-19
Filing date: 2023-09-19
Publication date: 2025-09-23
Anticipated expiration: 2043-09-19
Also published as: CN119665345A

Abstract

The invention provides a heat pump air conditioning system, wherein a refrigerant loop comprises a compressor, an air side outdoor heat exchanger, a water side outdoor heat exchanger and an indoor heat exchanger, the indoor heat exchanger is respectively connected with the air side outdoor heat exchanger and the water side outdoor heat exchanger through a liquid side communication pipe, an air side pipeline and a water side pipeline, a detection part is used for estimating the leakage of flammable refrigerant, a control part is configured to execute refrigerant recovery control, correct the opening degree of an air side throttling device based on the difference value of the flammable refrigerant temperature in the air side pipeline and the water side pipeline, and correct the opening degree of the water side throttling device based on the difference value of the flammable refrigerant temperature in the water side pipeline and the air side pipeline, so that the opening degree change of the air side throttling device and the water side throttling device under the refrigerant recovery control does not exceed a set range. The invention can avoid the problem of recovery failure caused by system shutdown due to early liquid filling in the refrigerant recovery process, so that the refrigerant recovery is complete and stable.

Description

Heat pump air conditioning system

Technical Field

The invention relates to the technical field of air conditioning, in particular to a heat pump air conditioning system.

Background

Conventional air conditioning systems employ R410A refrigerant. The R410A refrigerant is a fluorohydrofluorocarbon refrigerant comprising hydrogen, fluorine and carbon, and is a non-flammable gas. Since R410A has a relatively high ozone depletion potential, it has been gradually replaced by R290 and R32. R290 is natural gas propane, an alkane refrigerant containing only hydrogen and carbon, no fluorine, and therefore having low ozone destruction potential, a green refrigerant having less environmental impact, and R32 is a fluoroalkane refrigerant containing hydrogen, fluorine and carbon and having low ozone destruction potential but still higher than R290. R290 and R32 have good refrigeration properties, e.g., high latent heat, and can provide efficient cooling or heating.

However, R290 is a flammable gas and R32 has somewhat poorer combustion properties than R290, but both require special safety precautions to be taken during use and storage, especially if it leaks into the room and reaches a certain concentration during use, with the risk of explosion. In order to solve the problem, some solutions are proposed in the prior art, for example, the technical solution disclosed in the chinese patent application CN115289651a is that the' air conditioner comprises an indoor unit, an air outlet of which is provided with a refrigerant detecting member, a compressor is formed with a refrigerant outlet and a refrigerant inlet, a high-pressure detecting member is arranged between a four-way valve and the refrigerant outlet of the compressor, a low-pressure detecting member is formed between the four-way valve and the refrigerant inlet of the compressor, an indoor heat exchanger is communicated with the compressor through the four-way valve, an outdoor heat exchanger is communicated with the compressor through the four-way valve, a throttling device is arranged between the outdoor heat exchanger and the indoor heat exchanger, and a controller is configured to control the four-way valve to enable the indoor heat exchanger to operate as an evaporator in response to a leakage signal detected by the refrigerant detecting member, control the compressor to operate at a preset frequency in a preset recovery period, receive pressure signals of the high-pressure detecting member and the low-pressure detecting member, and control the opening of the throttling device in the preset recovery period. ''

The above-mentioned reference discloses a conventional split type air conditioner, in which the refrigerant capacity is relatively small, and for the multi-split type air conditioner, because the on-line pipeline is long, the number of indoor units is large, and there are different condensing capacities of a plurality of condensers at the same time, if the condensation capacity is regulated only by the throttling device as described in the reference during the recovery process, a situation that the condensing capacity is suddenly reduced and even the recovery is disabled due to shutdown is easy to occur because of too early filling of a certain condenser.

Disclosure of Invention

Aiming at the problems that an on-line pipeline is long, the number of indoor units is large, and a plurality of air conditioning systems with different condensers have different condensation capacities at the same time, a certain condenser is easy to be filled with liquid too early in the recovery process, and the condensation capacity suddenly drops to cause shutdown and cause recovery failure, the first aspect of the application designs and provides a heat pump air conditioning system.

The heat pump air conditioning system comprises a refrigerant loop for circulating a combustible refrigerant, wherein the refrigerant loop comprises a compressor, an air side outdoor heat exchanger, a water side outdoor heat exchanger and an indoor heat exchanger, the compressor is used for compressing and discharging the combustible refrigerant, the air side outdoor heat exchanger is used for enabling the combustible refrigerant discharged from the compressor to exchange heat with outdoor air, the water side outdoor heat exchanger is used for enabling the combustible refrigerant discharged from the compressor to exchange heat with water, the indoor heat exchanger is connected with the air side outdoor heat exchanger through a liquid side communication pipe and an air side pipeline, and the indoor heat exchanger is connected with the water side outdoor heat exchanger through a liquid side communication pipe and a water side pipeline.

In one or more embodiments of the present application, the indoor heat exchanger further includes a detection unit configured to estimate whether or not the flammable refrigerant leaks in a space where the indoor heat exchanger is located.

In one or more embodiments of the present application, the indoor heat exchanger further includes a control unit configured to perform refrigerant recovery control when the detection unit estimates that the flammable refrigerant leaks in a space where the indoor heat exchanger is located.

In one or more embodiments of the present application, an air-side restriction is provided on the air-side line, and a water-side restriction is provided on the water-side line.

In one or more embodiments of the present application, the control unit, when performing the refrigerant recovery control, further corrects the opening degree of the air-side restriction based on a difference in the flammable refrigerant temperatures in the air-side line and the water-side line, and corrects the opening degree of the water-side restriction based on a difference in the flammable refrigerant temperatures in the water-side line and the air-side line so that the opening degree changes in both of them do not exceed a set range of magnitudes under the refrigerant recovery control.

In one or more embodiments of the present application, the control unit calculates an air-side adjustment proportionality coefficient based on a difference in flammable refrigerant temperatures in the air-side piping and the water-side piping when performing the refrigerant recovery control, the air-side adjustment proportionality coefficient being a ratio of a first set constant to the difference in flammable refrigerant temperatures in the air-side piping and the water-side piping, and takes a product of the air-side adjustment proportionality coefficient and an opening of an air-side throttling device of a current adjustment cycle as an opening of a next adjustment cycle, the opening of the next adjustment cycle being equal to or smaller than the opening of the current adjustment cycle.

In one or more embodiments of the present application, the control unit calculates a water side adjustment proportionality coefficient based on a difference in flammable refrigerant temperatures in the water side pipe and the air side pipe when performing the refrigerant recovery control, the water side adjustment proportionality coefficient being a ratio of a second set constant to the difference in flammable refrigerant temperatures in the water side pipe and the air side pipe, and takes a product of the water side adjustment proportionality coefficient and an opening of a water side throttle device of a current adjustment cycle as an opening of a next adjustment cycle, the opening of the next adjustment cycle being equal to or smaller than the opening of the current adjustment cycle.

In one or more embodiments of the present application, the liquid side communication pipe is provided with a liquid side shutoff valve, and the air side communication pipe of the heat pump air conditioning system is further provided with an air side shutoff valve.

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.

In one or more embodiments of the present application, the control unit is configured to execute the refrigerant recovery control when the detection unit estimates that the flammable refrigerant leaks in a space in which any one of the indoor heat exchangers is located.

In one or more embodiments of the present application, the refrigerant recovery control includes disposing an indoor heat exchanger as an evaporator, controlling the liquid-side shutoff valve to shut off a fluid passage in the liquid-side communication pipe, controlling the air-side throttling device to be at a maximum opening, controlling the water-side throttling device to be at a maximum opening, and controlling the indoor throttling device to be at a maximum opening.

In one or more embodiments of the present application, the control unit is configured to correct the opening degree of the air-side throttling device based on a difference in the flammable refrigerant temperatures in the air-side piping and the water-side piping on the basis of the maximum opening degree, and correct the opening degree of the water-side throttling device based on a difference in the flammable refrigerant temperatures in the water-side piping and the air-side piping so that the opening degree changes in both under refrigerant recovery control do not exceed a set range.

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

In one or more embodiments of the present application, the refrigerant recovery control includes configuring an indoor heat exchanger as an evaporator, controlling the liquid-side shutoff valve to shut off the liquid-side communication 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.

In one or more embodiments of the present application, the control unit is configured to correct the opening degree of the air-side throttling device based on a difference in the flammable refrigerant temperatures in the air-side piping and the water-side piping on the basis of the operation opening degree, and correct the opening degree of the water-side throttling device based on a difference in the flammable refrigerant temperatures in the water-side piping and the air-side piping so that the opening degree changes in both under refrigerant recovery control do not exceed a set range.

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 operation opening degree of the water-side throttling device is generated according to the outlet supercooling degree of the water-side outdoor heat exchanger, and the operation opening degree of the air-side throttling device is generated according to the outlet supercooling degree of the air-side outdoor heat exchanger.

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 operation opening degree of the water-side throttling device is generated according to the degree of supercooling of the water-side outdoor heat exchanger outlet, and the operation opening degree of the air-side throttling device is generated according to the degree of superheat of the exhaust gas.

In one or more embodiments of the present application, the control unit may perform emergency control including configuring the water side outdoor heat exchanger as a condenser, operating the water side throttling device at a maximum opening degree, and estimating an emergency operation opening degree of the air side throttling device based on a degree of superheat of the exhaust gas after terminating the refrigerant recovery control.

The invention keeps the opening degree of the air side throttling device and the opening degree of the water side throttling device to be similar under the refrigerant recovery control, and the liquid levels in the air side outdoor heat exchanger and the water side outdoor heat exchanger rise at similar speeds and are kept at similar levels, so that the storage capacity of the two outdoor heat exchangers is fully exerted, the design capacity of the two outdoor heat exchangers is also large enough, the combustible refrigerant can be ensured to be stably, fully and completely recovered, and the safety risk is reduced to the minimum.

Other features and advantages of the present invention will become apparent upon review of the detailed description of the invention in conjunction with the drawings.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it will be obvious that the drawings in the following description are some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort to a person skilled in the art.

FIG. 1 is a schematic diagram of a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 2 is a schematic diagram of a refrigerant circuit in a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 3 is a flow chart of a control portion in a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 4 is a flow chart of a control portion of a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 5 is a flow chart of a control portion of a heat pump air conditioning system according to one or more embodiments of the present application;

fig. 6 is a schematic diagram of a refrigerant circuit before a heat pump air conditioning system according to one or more embodiments of the present application performs refrigerant recovery control.

FIG. 7 is a schematic diagram of a refrigerant circuit of a heat pump air conditioning system according to one or more embodiments of the present application when performing refrigerant recovery control;

FIG. 8 is a schematic diagram of a refrigerant circuit of a heat pump air conditioning system according to one or more embodiments of the present application when performing refrigerant recovery control;

FIG. 9 is a schematic diagram of a refrigerant circuit of a heat pump air conditioning system according to one or more embodiments of the present application after performing refrigerant recovery control;

FIG. 10 is a flow chart of a control portion of a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 11 is a flow chart of a control portion in a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 12 is a schematic diagram of a refrigerant circuit of a heat pump air conditioning system according to one or more embodiments of the present application before performing refrigerant recovery control;

FIG. 13 is a schematic diagram of a refrigerant circuit of a heat pump air conditioning system according to one or more embodiments of the present application when performing refrigerant recovery control;

FIG. 14 is a schematic diagram of a refrigerant circuit of a heat pump air conditioning system according to one or more embodiments of the present application when performing refrigerant recovery control;

FIG. 15 is a schematic diagram of a refrigerant circuit of a heat pump air conditioning system according to one or more embodiments of the present application after performing refrigerant recovery control;

FIG. 16 is a flow chart of a control portion of a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 17 is a flow chart of a control portion of a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 18 is a schematic diagram of a refrigerant circuit in a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 19 is a flow chart of a control portion of a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 20 is a flow chart of a control portion of a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 21 is a schematic diagram of a refrigerant circuit in a heat pump air conditioning system according to one or more embodiments of the present application;

FIG. 22 is a flow chart of a control portion of a heat pump air conditioning system according to one or more embodiments of the present application;

1, a heat pump air conditioning system; 11a, designating an indoor space; 11b, designating an indoor space; 100, refrigerant circuit, 12, detection unit, 13, control unit, 101, compressor, 102, air side outdoor heat exchanger, 103, air side throttle device, 104a, indoor throttle device, 104b, indoor throttle 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 throttle 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, 117, air side pipe temperature sensor, 118, water side pipe temperature sensor, 119, water inlet temperature sensor, 120, water outlet temperature sensor, 121, compressor, 123, water side air pressure sensor, 125, air pressure pipe, and air pressure sensor.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify description, and do not indicate or imply that the device or element in question must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the present application.

The terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying that the number of technical features indicated is indicated. Thus, a feature defining "first", "second" may include one or more of such features explicitly or implicitly. In the description of the present application, unless otherwise indicated, "a plurality of" means two or more.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, integrally connected, mechanically connected, electrically connected, directly connected, indirectly connected through an intermediate medium, or in communication with each other between two elements. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.

In the present invention, unless explicitly specified and limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features in direct contact, as well as the first and second features not in direct contact but in contact with another feature therebetween. Moreover, a first feature being "above", "above" and "upper" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "under" and "under" the second feature includes the first feature being directly under and obliquely under the second feature, or simply indicating that the first feature is less level than the second feature.

The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. In order to simplify the present disclosure, components and arrangements of specific examples are described below. They are, of course, merely examples and are not intended to limit the invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

Fig. 1 illustrates a schematic structural view of a heat pump air conditioning system provided by one or more embodiments of the present invention, and fig. 2 illustrates an example of a refrigerant circuit formed by the heat pump air conditioning system according to an embodiment of the present invention.

The heat pump air conditioning system 1 is installed in a building such as an apartment, a hotel, an office building, and a house. The heat pump air conditioning system 1 is configured to selectively perform a hot water supply operation and a heating operation simultaneously, or a hot water supply operation and a cooling operation simultaneously, or to perform a cooling operation independently, or to perform a hot water supply operation independently.

The heat pump air conditioning system 1 has a refrigeration cycle integrated therein. A compressor 101, a condenser, a throttle device, and an evaporator are used in the refrigeration cycle. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and refrigerating or heating an indoor space.

From the principle point of view, a low-temperature low-pressure refrigerant enters the compressor 101, the compressor 101 compresses a refrigerant gas in a high-temperature high-pressure state, and the compressed refrigerant gas is discharged. 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.

The throttle device expands the liquid-phase refrigerant in a high-temperature and high-pressure state formed by condensation in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the throttle device and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor 101. The evaporator may achieve a cooling effect by exchanging heat with a material to be cooled using latent heat of evaporation of a refrigerant. Throughout the cycle, the heat pump air conditioning system 1 can adjust the temperature of the indoor space.

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

The indoor unit and the outdoor unit are connected to each other by a liquid-side communication pipe 127 and a gas-side communication pipe 128. The liquid-side communication piping 127 and the gas-side communication piping 128 serve to flow the refrigerant so that the refrigerant can form and circulate in the refrigerant circuit 100.

In one or more embodiments of the present application, the liquid-side shutoff valve 109 is provided in the liquid-side communication pipe 127, and the gas-side shutoff valve 110 is provided in the gas-side communication pipe 128. The liquid-side shutoff valve 109 may shut off the fluid passage in the liquid-side communication pipe 127 or close to shutting off the fluid passage in the liquid-side communication pipe 127 at the minimum opening, and the gas-side shutoff valve 110 may shut off the fluid passage in the gas-side communication pipe 128 or close to shutting off the fluid passage in the gas-side communication pipe 128 at the minimum opening.

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 protection performance, and can also be other flammable refrigerants meeting industry standards.

The basic structure and functions of the outdoor unit are explained below. When the same system architecture is adopted, in the heat pump air conditioning system 1, the number of outdoor units can also be expanded to a plurality and operated in a group manner.

In one or more embodiments of the present application, the outdoor unit of the heat pump air conditioning system 1 refers to a portion of the refrigeration cycle including the compressor 101 and the air-side outdoor heat exchanger 102, and includes a portion of the hot water supply at the same time. The portion of the hot water supply includes a water side outdoor heat exchanger 113, the water side outdoor heat exchanger 113 being coupled (e.g., in parallel piping or a sleeve) with the water supply branch and the water usage branch so that water in the water supply branch (from the water source) can be heated and the heated water stored in the tank or directed to the area of water via the water usage branch. The portion of the hot water supply also includes a water pump 114.

The outdoor unit may perform a heating operation or a cooling operation at an outdoor side to supply energy for increasing an indoor temperature or energy for decreasing an indoor temperature to the indoor unit. The outdoor unit is also provided with a gas-liquid separator 108, an outdoor fan 106 and a reversing valve (for example, a four-way valve 124), and the outdoor unit is also provided with a liquid storage tank.

In the heating operation, the outdoor unit may form a refrigerant circuit 100 (hereinafter referred to as a heating cycle) for the heating operation, in which an air-side piping 125 (an air-side throttling device 103 is provided on the air-side piping 125), an air-side outdoor heat exchanger 102, a four-way valve 124 (e.g., a passage between an E-port and an S-port), a gas-liquid separator 108, a compressor 101, and the four-way valve 124 (e.g., a passage between a D-port and a C-port) are connected in this order from a liquid-side communication piping 127 to an air-side communication piping 128.

In the cooling operation, the outdoor unit may form a refrigerant circuit 100 (hereinafter referred to as a refrigeration cycle) for the cooling operation, in which a four-way valve 124 (e.g., a passage between the C port and the S port), the gas-liquid separator 108, the compressor 101, the four-way valve 124 (e.g., a passage between the D port and the E port), the air-side outdoor heat exchanger 102, and an air-side pipe 125 are connected in this order from the gas-side communication pipe 128 to the liquid-side communication pipe 127 (the air-side pipe 125 is provided with an air-side throttling device 103).

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 restriction 103 is adjustable, and in the present application, the air-side restriction 103 is implemented by an electronic expansion valve.

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

The water side restriction 112 is configured to reduce the pressure of the refrigerant and expand it. The opening degree of the water-side restriction 112 is adjustable, and in the present application, the water-side restriction 112 is implemented by an electronic expansion valve.

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

The air side outdoor heat exchanger 102 is configured to function as a condenser in a cooling operation and as an evaporator in a heating operation. The air-side outdoor heat exchanger 102 may exchange heat with the air flowing through the outdoor fan 106 to cause a phase change (condensation or evaporation) of the refrigerant flowing in the air-side outdoor heat exchanger 102. The rotational speed of the outdoor fan 106 may be controlled to change the flow rate of air heat exchanged with the air-side outdoor heat exchanger 102 by adjusting the rotational speed. The outdoor fan 106 may be an axial flow fan, a cross flow fan, or other alternative fan forms. The outdoor fan 106 is disposed near the air-side outdoor heat exchanger 102.

The water side outdoor heat exchanger 113 is configured to function as a condenser in a hot water supply operation, and the water side outdoor heat exchanger 113 can exchange heat with water flowing in a water supply branch and a water use branch, which are provided near the water side outdoor heat exchanger 113. The water supply branch is provided with a water inlet temperature sensor 119, and the water supply branch is provided with a water outlet temperature sensor 120.

The air-side pipe 125 and the water-side pipe 126 are connected to the liquid-side communication pipe 127, respectively, and the air-side pipe 125 and the water-side pipe 126 are connected in parallel with each other. That is, the indoor heat exchanger is connected to the air-side outdoor heat exchanger 102 through the liquid-side communication pipe 127 and the air-side pipe 125, and is connected to the water-side outdoor heat exchanger 113 through the liquid-side communication pipe 127 and the water-side pipe 126.

The gas-liquid separator 108 is provided on the suction side of the compressor 101, and is a shell-like member for gas-liquid separation and storage of the refrigerant, and can store an excessive amount of refrigerant.

An outdoor control circuit is provided in the outdoor unit. The outdoor control circuit is arranged in an electric box with good sealing performance and heat dissipation function. The outdoor control circuit comprises a processor, a storage unit, an input/output interface, a communication interface and other components. The processor may be a special purpose processor, a Central Processing Unit (CPU), or the like. The processor may access the memory unit to execute instructions or applications stored in the memory unit to implement the relevant functions. The memory unit may include volatile memory and/or nonvolatile memory. The input/output interface may be communicatively coupled to various sensors disposed in the outdoor unit to receive sensed values of the various sensors disposed in the outdoor unit, including, but not limited to, a compressor discharge temperature sensor 121, a compressor suction pressure sensor 123, a compressor discharge pressure sensor 122, an air side line temperature sensor 117 (described in detail below), a water side line temperature sensor 118 (described in detail below), and the like. The input/output interface may also be communicatively connected to devices such as the inverter, the compressor 101, the outdoor fan 106, the four-way valve 124, the air-side throttling device 103, the water-side throttling device 112, etc., to output control instructions generated by the processor thereto. The communication interface may support different wireless communication protocols, such as Wi-Fi, bluetooth, near field communication, NB-loT, etc., to communicatively connect with other electronic devices, including but not limited to cloud servers, computers (kiosks), smartphones, tablets, PDAs, smart control tools, wearable devices, and vehicle-mounted devices, etc.

The structure and function of the indoor units will be described below, taking one of them as an example. The following description is equally applicable to other indoor units.

The indoor unit performs a cooling operation or a heating operation using energy generated by the outdoor unit to raise the indoor temperature or energy to lower the indoor temperature. The indoor unit includes an indoor heat exchanger (105 a, 105 b) and an indoor throttle device (104 a, 104 b) connected in series. Indoor fans (107 a, 107 b) are provided near the indoor heat exchangers (105 a, 105 b) to send heated or cooled air to the air-conditioned room. The indoor fans (107 a, 107 b) can be axial flow fans or cross flow fans, or other fans which can achieve the same function.

The indoor heat exchangers (105 a, 105 b) function as condensers in the heating operation and as evaporators in the cooling operation. The refrigerant in the indoor heat exchanger exchanges heat with the air flowing through the indoor fan, so that the refrigerant therein undergoes a phase change (condensation or evaporation).

The indoor throttle device (104 a, 104 b) is configured to reduce the pressure of the refrigerant and expand it. The opening degree of the indoor throttle device (104 a, 104 b) is adjustable, and in the application, the indoor throttle device (104 a, 104 b) is realized by an electronic expansion valve.

The indoor unit may adopt a wall-mounted air supply structure, a floor-mounted air supply structure, an air duct type air supply structure, an air supply structure embedded in a ceiling, or the like. The air supply structure comprises a shell, an air return port and an air supply port, wherein the shell is provided with an air suction port and an air supply port for supplying air subjected to heat exchange to an air conditioning room.

The indoor unit can be provided with a wire controller, a remote controller or a mobile control terminal in a matching way so as to input set temperature, an operation mode, display real-time temperature, system operation state and the like. The mobile control terminal may be a computer, tablet, smart phone, wearable device, etc.

An indoor control circuit is provided in the indoor unit. The indoor control circuit is arranged in an electric box with good sealing performance and heat dissipation function. The indoor control circuit comprises a processor, a storage unit, an input/output interface, a communication interface and other components. The processor may be a special purpose processor, a Central Processing Unit (CPU), or the like. The processor may access the memory unit to execute instructions or applications stored in the memory unit to implement the relevant functions. The memory unit may include volatile memory and/or nonvolatile memory. The input/output interface may be communicatively connected to various sensors provided in the indoor unit to receive detection values of the various sensors provided in the indoor unit, for example, the input/output port in the indoor control circuit is connected to a flammable refrigerant concentration sensor (111 a,111 b) for detecting a flammable refrigerant concentration in a designated indoor space (11 a,11 b), the designated indoor space (11 a,11 b) being, for example, a space where an indoor heat exchanger is located, including but not limited to an air-conditioned room covered by a blast air, an installation space of the indoor unit and an interior of a housing, and also connected to a liquid pipe temperature sensor (115 a, 115 b), an air pipe temperature sensor (116 a, 116 b). The communication interface may support different wireless communication protocols, such as Wi-Fi, bluetooth, etc.

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 or not the space in which the indoor heat exchanger is located has a flammable refrigerant leak, and for example, to estimate based on a flammable refrigerant concentration threshold value set in advance, and to estimate that the space in the specified indoor space has a flammable refrigerant leak when the flammable refrigerant concentration exceeds the concentration threshold value. The control unit 13 is configured to execute refrigerant recovery control when the detection unit 12 estimates that there is a leak of the flammable refrigerant in the space in which the indoor heat exchanger is located. When a plurality of outdoor units are provided, the control unit 13 is configured to execute refrigerant recovery control when the detection unit 12 estimates that the flammable refrigerant leaks in the space where any one of the indoor heat exchangers is located.

In one or more embodiments of the present application, the function of the control unit 13 may be performed by an indoor control circuit, the function of the control unit 13 may be performed by an outdoor control circuit, the function of the control unit 13 may be performed by a communication-connected indoor control circuit and outdoor control circuit together, or the function of the control unit 13 may be performed by a cloud server that is in communication with the indoor control circuit and/or the outdoor control circuit.

The refrigerant recovery control is to recover the flammable refrigerant in the indoor unit to the outdoor side by using the operation of the compressor 101 to wait for further maintenance treatment, thereby isolating the potential danger in the outdoor environment, reducing the possibility of approaching the ignition source, avoiding safety accidents that cause fire and explosion, and endangering the life and property safety of personnel. Because the condensing capacities of the air side outdoor heat exchanger 102 and the water side outdoor heat exchanger 113 are different, a situation that one outdoor heat exchanger is too early full of liquid may occur in the refrigerant recovery control process, and 'full of liquid' means that the refrigerant in the condenser is full of the condenser in a liquid phase state, rather than evaporating or condensing under normal working conditions, at this time, the pressure of a high-pressure part of the heat pump air conditioning system 1 may rise or even exceed a design range, the compressor 101 may be subjected to abnormal working load, and the compressor 101 is stopped, but at this time, the flammable refrigerant is not completely recovered, remains on the indoor side and the system is leaked or damaged, and the flammable refrigerant may further leak into the surrounding environment, so that the whole recovery control is disabled.

To solve this problem, in one or more embodiments of the present application, the control section 13 corrects the opening degree of the air-side restriction device 103 based on the difference in the flammable refrigerant temperatures in the air-side piping 125 and the water-side piping 126 (shown in step S102 in fig. 3) and corrects the opening degree of the water-side restriction device 112 based on the difference in the flammable refrigerant temperatures in the water-side piping 126 and the air-side piping 125 (shown in step S103 in fig. 3) so that the opening degree changes in both under the refrigerant recovery control do not exceed the set range (shown in step S104 in fig. 3) when the refrigerant recovery control is performed (shown in step S101 in fig. 3).

That is, the opening degree of the air-side throttling device 103 and the opening degree of the water-side throttling device 112 are kept close to each other under the refrigerant recovery control, and the liquid levels in the air-side outdoor heat exchanger 102 and the water-side outdoor heat exchanger 113 are raised at similar speeds and kept at similar levels, so that the storage capacities of the two outdoor heat exchangers are fully exerted, the design capacities of the two outdoor heat exchangers are also sufficiently large, the combustible refrigerant can be ensured to be stably, fully and completely recovered, and the safety risk is reduced to the minimum.

The set amplitude range may be a constant, which is written in advance by the technician into the storage unit for storage, and the set amplitude has the effect of making the opening degree of the air-side throttling device 103 and the opening degree of the water-side throttling device 112 in the process of changing always similar under the refrigerant recovery control, which is related to the design capacity of the heat pump air conditioning system 1, and the numerical value thereof is not limited any further.

In one or more embodiments of the present application, the water side line temperature sensor 118 is disposed downstream of the outlet of the water side outdoor heat exchanger 113 in the direction of the refrigeration cycle, and the air side line temperature sensor 117 is disposed downstream of the outlet of the air side outdoor heat exchanger 102.

In one or more embodiments of the present application, the control portion 13 calculates an air-side adjustment proportionality coefficient (shown as step S202 in fig. 4) based on the difference in the flammable refrigerant temperatures in the air-side piping 125 and the water-side piping 126 when performing the refrigerant recovery control (shown as step S201 in fig. 4), the air-side adjustment proportionality coefficient being a ratio of the first set constant to the difference in the flammable refrigerant temperatures in the air-side piping 125 and the water-side piping 126. The controller takes the product of the air-side adjustment proportionality coefficient and the opening degree of the air-side throttle device 103 in the current adjustment period as the opening degree of the next adjustment period (as shown in step S203 in fig. 4), and the opening degree of the next adjustment period is smaller than or equal to the opening degree of the current adjustment period.

That is, the formula is:

EVO(n)-EVO(n-1)≤0;

EVO(n)=EVO(n-1)×c₁/(T_e-T_rl);

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 (i.e., the pipe temperature of the air-side pipeline 125), T _rl is the flammable refrigerant temperature of the water-side pipeline 126 (i.e., the pipe temperature of the water-side pipeline 126), c ₁ is a first set constant, and 2 c ₁≤5.c₁/(T_e-T_rl is the air-side adjustment proportionality coefficient.

In one or more embodiments of the present application, the control portion 13 calculates a water-side adjustment scaling factor (shown as step S302 in fig. 5) based on the difference in the temperatures of the flammable refrigerants in the water-side pipe 126 and the air-side pipe 125 when performing the refrigerant recovery control (shown as step S301 in fig. 5). The water side adjustment scaling factor is the ratio of the second set constant to the difference in the temperatures of the flammable refrigerants in the water side pipe 126 and the air side pipe 125. The controller takes the product of the water-side adjustment proportionality coefficient and the opening of the water-side restriction 112 of the current adjustment period as the opening of the next adjustment period (as shown in step S303 in fig. 5). The opening degree of the next adjusting period is smaller than or equal to the opening degree of the current adjusting period.

That is, the formula is:

EVw(n)-EVw(n-1)≤0;

EVw(n)=EVw(n-1)×c₂/(T_rl-T_e);

Wherein EVw (n) is the opening of the water-side throttling device 112 in the next adjustment cycle, EVw (n-1) is the opening of the air-side throttling device 103 in the current adjustment cycle, T _e is the combustible refrigerant temperature of the air-side pipeline 125 (i.e., the pipe temperature of the air-side pipeline 125), T _rl is the combustible refrigerant temperature of the water-side pipeline 126 (i.e., the pipe temperature of the water-side pipeline 126), c ₂ is a second set constant, and 2≤c ₂≤5.c₂/(T_rl-T_e is the water-side adjustment scaling factor.

In one or more embodiments of the present application, the first set constant c ₁ and the second set constant c ₂ are preferably equal.

Because the working medium is more sensitive to temperature change in the heat pump air conditioning system 1, the temperature is used as a parameter temperature to have relatively quick response speed and more stable test condition, and the air side regulation proportion coefficient and the water side regulation proportion coefficient can be calculated by adopting the temperature to generate an accurate opening correction value more quickly, so that the recovery speed is ensured, and the conditions of large leakage and low recovery speed are avoided

The correction process of the above-described air-side throttling device 103 and water-side throttling device 112 to ensure the two values are close will be described in further detail below in conjunction with the overall process of the flammable refrigerant recovery control. Fig. 6, 7, 8 and 9 show a complete flammable refrigerant recovery control process.

The control unit 13 is configured to execute refrigerant recovery control when the detection unit 12 estimates that the flammable refrigerant leaks in the space in which any one of the indoor heat exchangers is located (as shown in step S401 in fig. 10).

The refrigerant recovery control includes:

The indoor heat exchanger is configured as an evaporator (as shown in step S402 in fig. 10).

The indoor unit may perform a heating operation or a cooling operation before performing the refrigerant recovery control.

As shown by an arrow F1 in fig. 6, when the indoor unit performs the cooling operation, the liquid-side shutoff valve 109 and the gas-side shutoff valve 110 remain in the on state. Low pressure gas refrigerant is drawn into the compressor 101. The refrigerant is compressed in the compressor 101 to a high temperature and high pressure state, and is 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 having flowed into the air-side outdoor heat exchanger 102 exchanges heat with air guided through the outdoor fan 106 to become high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows out of the outdoor unit through the liquid-side communication pipe 127, and then flows into the two indoor units. The refrigerant having flowed to the indoor unit is decompressed by the air-side throttle device 103 and the indoor throttle devices (104 a, 104 b), thereby becoming a low-pressure two-phase gas-liquid refrigerant or a low-pressure liquid refrigerant. The refrigerant then flows into the indoor heat exchangers (105 a, 105 b).

The low-pressure refrigerant having flowed into the indoor heat exchangers (105 a, 105 b) evaporates in the indoor heat exchangers (105 a, 105 b) to become low-pressure gas refrigerant, and flows out of the indoor heat exchangers (105 a, 105 b). The low-pressure gas refrigerant having flowed out of the indoor heat exchangers (105 a, 105 b) flows into the outdoor unit through the gas-side communication pipe 128. The low pressure gas refrigerant having 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.

The high-temperature and high-pressure refrigerant can simultaneously flow into the water-side outdoor heat exchanger 113 while hot water supply is achieved.

When the indoor unit performs the heating operation, the liquid-side shutoff valve 109 and the gas-side shutoff valve 110 remain in the on state. As shown by an arrow F4 in fig. 18, low-pressure gas refrigerant is sucked into the compressor 101. The refrigerant is compressed in the compressor 101 to a high temperature and high pressure state, is discharged from the compressor 101, flows through the four-way valve 124, and flows out of the outdoor unit through the gas-side communication pipe 128. Then, the high pressure gas refrigerant having flowed out of the outdoor unit flows into the indoor unit. The refrigerant having flowed into the indoor unit flows into the indoor heat exchangers (105 a, 105 b). The high-pressure gas refrigerant is condensed in the indoor heat exchangers (105 a, 105 b) to become high-pressure liquid refrigerant, and flows out of the indoor heat exchangers (105 a, 105 b).

The high-pressure liquid refrigerant from the indoor heat exchangers (105 a, 105 b) is depressurized by the indoor throttle devices (104 a, 104 b) and the air-side throttle device 103, and becomes a low-pressure two-phase gas-liquid refrigerant that flows out of the indoor units via the liquid-side communication 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, turns into a low-pressure gas refrigerant, and flows out of the air-side outdoor heat exchanger 102. The refrigerant having 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 again sucked into the compressor 101.

The high-temperature and high-pressure refrigerant may also simultaneously flow into the water-side outdoor heat exchanger 113 while achieving hot water supply.

If only the cooling operation is performed, the water-side restriction 112 is in a closed state, the air-side restriction 103 is at a maximum opening, and the system discharge superheat degree is controlled by the indoor restrictions (104 a, 104 b), i.e., the system discharge superheat degree (the difference between the compressor discharge temperature and the saturation temperature corresponding to the compressor discharge pressure) is maintained at the target discharge superheat degree by adjusting the indoor restrictions (104 a, 104 b).

In performing the refrigerant recovery control, if the indoor unit performs the cooling operation, no additional control is performed, and the indoor heat exchanger is configured as an evaporator.

In executing the refrigerant recovery control, if the indoor unit executes the heating operation, it is first switched to execute the cooling operation, the indoor heat exchanger is configured as an evaporator, and the cooling operation is maintained for a while, for example, a seconds, a is a constant, 0≤a <90.

Further, the liquid-side shutoff valve 109 is controlled to shut off the liquid-side communication pipe 127 (as shown in step S403 in fig. 10).

As shown in fig. 7, the air-side throttling device 103 is further controlled to have the maximum opening MAX (as shown in step S404 in fig. 10), the water-side throttling device 112 is controlled to have the maximum opening MAX (as shown in step S405 in fig. 10), and the indoor throttling device is controlled to have the maximum opening MAX (as shown in step S406 in fig. 10). At the same time, the indoor fan speed is driven to increase to a high-speed gear (MAX), the outdoor fan 106 speed is driven to increase to a high-speed gear (MAX), the water pump 114 is driven to increase to a high-speed gear (MAX), and preferably both are driven to increase to an upper limit value, so as to increase the recovery speed, and the flow of the refrigerant at the time of recovery is shown by an arrow F2 in fig. 7.

The indoor throttle device is further kept at the maximum opening (MAX), and the opening of the air-side throttle device 103 is corrected based on the difference in the flammable refrigerant temperature in the air-side piping 125 and the water-side piping 126 (as shown in step S407 in fig. 10), and the opening of the water-side throttle device 112 is corrected based on the difference in the flammable refrigerant temperature in the water-side piping 126 and the air-side piping 125 (as shown in step S408 in fig. 10), so that the opening changes in both under the refrigerant recovery control do not exceed the set range, and the refrigerant flows are as shown in fig. 8.

That is, while the refrigerant recovery control is being performed, both EVO (n-1) and EVw (n-1) are the maximum opening degrees, and correction is made stepwise based on the air-side adjustment scaling factor and the water-side adjustment scaling factor in a plurality of adjustment periods.

After the indoor unit refrigerant is evacuated, the refrigerant recovery is completed.

The estimated refrigerant evacuation may be based on a number of steps as shown in fig. 11:

It is determined whether the pressure on the suction side of the compressor 101 does not exceed the pre-warning condition, i.e., whether P _s≤bM_pa is satisfied, as shown in step S409 in fig. 11, b is a constant, and b is equal to or less than 0.2.

If the pressure on the suction side of the compressor 101 does not exceed the warning condition, the refrigerant recovery is terminated as shown in step S410 in fig. 11.

The control gas side shutoff valve 110 shuts off the fluid passage in the gas side communication pipe 128 as shown in step S411 in fig. 11.

The indoor throttle device is controlled to be at the minimum opening degree as shown in step S412 in fig. 11.

The refrigeration cycle after the completion of the recovery is shown in fig. 9.

Fig. 12, 13, 14 and 15 show another complete flammable refrigerant recovery control process.

The control unit 13 is configured to execute refrigerant recovery control when the detection unit 12 estimates that the flammable refrigerant leaks in the space in which any one of the indoor heat exchangers is located (as shown in step S501 in fig. 16).

The refrigerant recovery control includes:

The indoor heat exchanger is configured as an evaporator (as shown in step S502 in fig. 16).

When the indoor unit performs the cooling operation, the liquid-side shutoff valve 109 and the gas-side shutoff valve 110 remain in the on state. Low pressure gas refrigerant is drawn into the compressor 101. The refrigerant is compressed in the compressor 101 to a high temperature and high pressure state, and is 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 having flowed into the air-side outdoor heat exchanger 102 is changed into a high-pressure liquid refrigerant by heat exchange from air guided through the indoor fan. The high-pressure liquid refrigerant flows out of the outdoor unit through the liquid-side communication pipe 127, and then flows into the two indoor units. The refrigerant having flowed to the indoor unit is depressurized 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.

The low pressure refrigerant having flowed into the indoor heat exchanger is evaporated in the indoor heat exchanger to become low pressure gas refrigerant, and flows out of the indoor heat exchanger. The low-pressure gas refrigerant having flowed out of the indoor heat exchanger flows into the outdoor unit through the gas-side communication pipe 128. The low pressure gas refrigerant having 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.

When the indoor unit performs the heating operation, the liquid-side shutoff valve 109 and the gas-side shutoff valve 110 remain in the on state. As shown in fig. 18, low-pressure gas refrigerant is sucked into the compressor 101. The refrigerant is compressed in the compressor 101 to a high temperature and high pressure state, is discharged from the compressor 101, flows through the four-way valve 124, and flows out of the outdoor unit through the gas-side communication pipe 128. The high pressure gas refrigerant having flowed out of the outdoor unit then flows into the indoor unit. The refrigerant having 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.

The high-pressure liquid refrigerant from the indoor heat exchanger is depressurized by the indoor throttle device and the air-side throttle device 103, and becomes a low-pressure two-phase gas-liquid refrigerant that flows out of the indoor unit through the liquid-side communication 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, turns into a low-pressure gas refrigerant, and flows out of the air-side outdoor heat exchanger 102. The refrigerant having 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 again sucked into the compressor 101.

The refrigerant circuit at this time is shown in fig. 12.

Further, the liquid-side shutoff valve 109 is controlled to shut off the liquid-side communication pipe 127 (as shown in step S503 in fig. 16).

As shown in fig. 13, the air-side throttling device 103 is further controlled to be at the operation opening degree (as shown in step S504 in fig. 16), the water-side throttling device 112 is controlled to be at the operation opening degree (as shown in step S505 in fig. 16), and the indoor throttling device is controlled to be at the maximum opening degree MAX (as shown in step S506 in fig. 16). At the same time, the indoor fan speed is driven to increase to a high-speed gear (MAX), the outdoor fan 106 speed is driven to increase to a high-speed gear (MAX), and the water pump 114 is driven to increase to a high-speed gear (MAX), preferably both to increase to an upper limit value, so as to improve the recovery speed.

Further, the indoor throttle device is kept at the maximum opening (MAX), and the opening of the air-side throttle device 103 is corrected based on the difference in the flammable refrigerant temperature in the air-side pipe 125 and the water-side pipe 126 on the basis of the operating opening (as shown in step S507 in fig. 16), and the opening of the water-side throttle device 112 is corrected based on the difference in the flammable refrigerant temperature in the water-side pipe 126 and the air-side pipe 125 (as shown in step S508 in fig. 16) so that the opening changes in both under the refrigerant recovery control do not exceed the set range.

That is, while the refrigerant recovery control is being executed, both EVO (n-1) and EVw (n-1) are the operation opening degrees, and correction is made stepwise based on the air-side adjustment scaling factor and the water-side adjustment scaling factor in a plurality of adjustment periods.

The following describes a method of generating the operation opening degree, and 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. 19 (step S601 in fig. 19), the operation opening degree of the water-side throttle device 112 is generated from the degree of supercooling of the outlet of the water-side outdoor heat exchanger 113 (step S602 in fig. 19), and the operation opening degree of the air-side throttle device 103 is generated from the degree of supercooling of the outlet of the air-side outdoor heat exchanger 102 (step S603 in fig. 19).

The degree of supercooling at the outlet of the water side outdoor heat exchanger 113 may be calculated from the difference of the saturation temperatures corresponding to the temperature of the water side pipe 126 and the exhaust pressure, and the degree of supercooling at the outlet of the air side outdoor heat exchanger 102 may be calculated from the difference of the saturation temperatures corresponding to the temperature of the air side pipe 125 and the exhaust pressure.

As shown in fig. 20, when the air-chamber external heat exchanger is configured as an evaporator and the water-side external heat exchanger 113 is configured as a condenser (as shown in step S701 in fig. 20), the operation opening degree of the water-side throttling device 112 is generated from the degree of supercooling of the outlet of the water-side external heat exchanger 113 (as shown in step S702 in fig. 20), and the operation opening degree of the air-side throttling device 103 is generated from the degree of superheat of the exhaust gas (as shown in step S703 in fig. 20).

The degree of supercooling at the outlet of the water-side outdoor heat exchanger 113 may be calculated from the difference between the saturation temperature corresponding to the temperature of the water-side piping 126 and the discharge pressure, and the degree of superheat of the discharge gas may be calculated from the difference between the saturation temperature corresponding to the discharge temperature of the compressor 101 and the discharge pressure of the compressor 101.

When the water-side restriction device 112 and the air-side restriction device 103 are operated at the operation opening degrees (for example, a cooling operation + a hot water supply, a heating operation + a hot water supply), the indoor restriction device controls the supercooling degree of the indoor unit, i.e., the opening degree of the indoor restriction device is generated based on the difference between the liquid pipe temperature sensor and the detection value and the saturation temperature corresponding to the discharge pressure of the compressor 101.

The step number of the electronic expansion valve is adjusted according to the target value of the superheat degree, so as to eliminate the deviation of the superheat degree, which is a common technical means in the art, and will not be further described herein.

The estimated refrigerant evacuation may be based on a number of steps as shown in fig. 17:

It is determined whether the pressure on the suction side of the compressor 101 does not exceed the warning condition, i.e., whether P _s≤bM_pa is satisfied, as shown in step S509 in fig. 17.

If the pressure on the suction side of the compressor 101 does not exceed the warning condition, the refrigerant recovery is terminated as shown in step S510 in fig. 17.

The control gas side shutoff valve 110 shuts off the fluid passage in the gas side communication pipe 128 as shown in step S511 in fig. 17.

The indoor throttle device is controlled to be at the minimum opening degree as shown in step S512 in fig. 17.

The refrigeration cycle after the completion of the recovery is shown in fig. 15.

As shown in step S806 in fig. 22, after the recovery is completed, the heat pump air conditioning system 1 also optionally has an emergency control mode. The emergency control mode includes configuring the water-side outdoor heat exchanger 113 as a condenser, operating the water-side throttle device 112 at a maximum opening, and estimating an emergency operation opening of the air-side throttle device 103 from the degree of superheat of the exhaust gas.

As shown in fig. 21, when the outdoor unit performs the emergency control mode operation, the liquid-side shutoff valve 109 and the gas-side shutoff valve 110 remain in the shut-off state. Low pressure gas refrigerant is drawn into the compressor 101. The refrigerant is compressed in the compressor 101 to a high temperature and high pressure state, and is discharged from the compressor 101. High temperature and high pressure refrigerant inflow water a side outdoor heat exchanger 113. The high-pressure gas refrigerant having flowed into the water-side outdoor heat exchanger 113 exchanges heat with water in the water supply branch and the water usage branch to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows out of the water-side outdoor heat exchanger 113 via the water-side piping 126, and then flows to the air-side outdoor heat exchanger 102. The refrigerant having flowed to the air-side outdoor heat exchanger 102 is depressurized by the air-side throttling device 103 to become a low-pressure two-phase gas-liquid refrigerant or a low-pressure liquid refrigerant, flows through the four-way valve 124 and the gas-liquid separator 108, and is again sucked into the compressor 101.

In cold weather conditions, the emergency control mode may maintain the indoor environment within an acceptable range until maintenance personnel handle the leak.

In the description of the above embodiments, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.

Claims

1. A heat pump air conditioning system, comprising:

A refrigerant circuit configured for a flammable refrigerant cycle, comprising:

a compressor that compresses and discharges the flammable refrigerant;

an air-side outdoor heat exchanger that exchanges heat between the flammable refrigerant discharged from the compressor and outdoor air;

a water-side outdoor heat exchanger that exchanges heat between the flammable refrigerant discharged from the compressor and water;

And

An indoor heat exchanger connected to the air-side outdoor heat exchanger through a liquid-side communication pipe and an air-side pipeline, and connected to the water-side outdoor heat exchanger through a liquid-side communication pipe and a water-side pipeline;

a detection unit configured to estimate whether or not the flammable refrigerant leaks in a space in which 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 leaks in a space in which the indoor heat exchanger is located;

It is characterized in that the method comprises the steps of,

An air side throttling device is arranged on the air side pipeline, and a water side throttling device is arranged on the water side pipeline;

The control unit corrects the opening of the air-side throttle device based on the difference in the temperature of the flammable refrigerant in the air-side line and the water-side line, and corrects the opening of the water-side throttle device based on the difference in the temperature of the flammable refrigerant in the water-side line and the air-side line so that the opening changes in both of them do not exceed a set range when the refrigerant recovery control is executed.

2. The heat pump air conditioning system according to claim 1, wherein,

The control unit calculates an air-side adjustment proportionality coefficient based on a difference in flammable refrigerant temperatures in the air-side piping and the water-side piping when performing refrigerant recovery control, the air-side adjustment proportionality coefficient being a ratio of a first set constant to the difference in flammable refrigerant temperatures in the air-side piping and the water-side piping, and takes a product of the air-side adjustment proportionality coefficient and an opening degree of an air-side throttling device in a current adjustment cycle as an opening degree of a next adjustment cycle, the opening degree of the next adjustment cycle being equal to or smaller than the opening degree of the current adjustment cycle.

3. The heat pump air conditioning system according to claim 1, wherein,

The control unit calculates a water side adjustment proportionality coefficient based on a difference in flammable refrigerant temperature between the water side pipe and the air side pipe when performing refrigerant recovery control, wherein the water side adjustment proportionality coefficient is a ratio of a second set constant to the difference in flammable refrigerant temperature between the water side pipe and the air side pipe, and takes a product of the water side adjustment proportionality coefficient and an opening of a water side throttle device in a current adjustment cycle as an opening of a next adjustment cycle, and the opening of the next adjustment cycle is equal to or smaller than the opening of the current adjustment cycle.

4. A heat pump air conditioning system according to any of claims 1 to 3, characterized in that,

A liquid side shutoff valve is arranged on the liquid side communication pipe;

further comprises:

a gas side communication pipe provided with a gas side shutoff valve;

the indoor heat exchangers are provided with a plurality of indoor throttling devices, 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 leaks in a space in which any one of the indoor heat exchangers is located, the refrigerant recovery control including:

The indoor heat exchanger is configured as an evaporator;

Controlling the liquid-side shutoff valve to shut off a fluid passage in the liquid-side communication 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;

And correcting the opening of the air side throttling device based on the difference of the combustible refrigerant temperatures in the air side pipeline and the water side pipeline on the basis of the maximum opening, and correcting the opening of the water side throttling device based on the difference of the combustible refrigerant temperatures in the water side pipeline and the air side pipeline so that the opening variation of the water side throttling device and the water side throttling device under the refrigerant recovery control does not exceed a set range.

5. The heat pump air conditioning system according to claim 4, wherein,

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 shutoff valve to shut off the fluid passage in the gas side communication pipe, and controls the indoor throttle device to be at a minimum opening.

6. A heat pump air conditioning system according to any of claims 1 to 3, characterized in that,

Further comprises:

A liquid-side communication pipe provided with a liquid-side shutoff valve;

a gas side communication pipe provided with a gas side shutoff valve;

The indoor heat exchanger is configured as an evaporator;

Controlling the liquid side shutoff valve to shut off the liquid side communication pipe;

controlling the air side throttling device to be at a working opening degree;

Controlling the water side throttling device to be at a working opening degree;

Controlling the indoor throttling device to be at the maximum opening;

And correcting the opening of the air side throttling device based on the difference of the combustible refrigerant temperatures in the air side pipeline and the water side pipeline on the basis of the working opening, and correcting the opening of the water side throttling device based on the difference of the combustible refrigerant temperatures in the water side pipeline and the air side pipeline so that the opening change of the air side throttling device and the water side throttling device under the refrigerant recovery control does not exceed a set range.

7. The heat pump air conditioning system according to claim 6, wherein,

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 degree of the water side throttling device is generated according to the outlet supercooling degree of the water side outdoor heat exchanger, and the working opening degree of the air side throttling device is generated according to the outlet supercooling degree of the air side outdoor heat exchanger.

8. The heat pump air conditioning system according to claim 6, wherein,

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 degree of the water side throttling device is generated according to the outlet supercooling degree of the water side outdoor heat exchanger, and the working opening degree of the air side throttling device is generated according to the exhaust superheat degree.

9. The heat pump air conditioning system according to claim 6, wherein,

10. A heat pump air conditioning system, comprising:

A refrigerant circuit configured for a flammable refrigerant cycle, comprising:

a compressor that compresses and discharges the flammable refrigerant;

And

The indoor heat exchanger is connected with the air side outdoor heat exchanger through an air side pipeline and connected with the water side outdoor heat exchanger through a water side pipeline;

A detection portion configured to detect whether or not the flammable refrigerant leaks in a space in which the indoor heat exchanger is located;

And

It is characterized in that the method comprises the steps of,

The control unit corrects the opening of the air-side throttle device based on a difference in the temperature of the flammable refrigerant in the air-side line and the water-side line when the refrigerant recovery control is executed, and corrects the opening of the water-side throttle device based on a difference in the temperature of the flammable refrigerant in the water-side line and the air-side line so that the opening changes in both under the refrigerant recovery control do not exceed a set range;

The control unit may execute emergency control after terminating the refrigerant recovery control, the emergency control including configuring the water side outdoor heat exchanger as a condenser, operating the water side throttling device at a maximum opening, and estimating an emergency operation opening of the air side throttling device according to a degree of superheat of the exhaust gas.