A multi-connected air conditioner

Abstract

The present invention discloses a multi-connected air conditioner, which includes an outdoor unit. The outdoor unit includes a compressor, a water-fluorine heat exchanger, an outdoor heat exchanger, a first electronic expansion valve, a second electronic expansion valve, an outdoor ambient temperature sensor, and a controller. The water-fluorine heat exchanger includes a refrigerant passage and a water passage. The outdoor heat exchanger is connected in parallel with the refrigerant passage and is connected to the exhaust port at one end. The first electronic expansion valve and the second electronic expansion valve are respectively connected in series with the outdoor heat exchanger and the refrigerant passage, and are respectively used to control the refrigerant flow rate passing through them. The outdoor ambient temperature sensor is used to detect the outdoor ambient temperature. The controller is configured with a hot water mode and controls the opening degrees of the first electronic expansion valve and the second electronic expansion valve according to the outdoor ambient temperature. The present invention leads a refrigerant pipeline from the compressor exhaust side to the water-fluorine heat exchanger, and controls the opening degrees of the first electronic expansion valve and the second electronic expansion valve to adjust the proportion of condensed hot water, realizing the refrigeration and hot water functions, reducing costs, saving energy, and improving the user experience.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and particularly relates to a multi-connected air conditioner. Background Art

[0002] For a traditional multi-connected air conditioner to achieve the functions of dehumidifying without cooling or heating and cooling simultaneously, it is necessary to design a three-pipe air conditioning system and add solenoid valves or four-way valves in the system to control the flow direction of high and low pressure refrigerants, and it is necessary to cooperate with a dedicated indoor unit with two heat exchangers for use. The system and structure design are complex, the number of components is large, the indoor unit needs to have two heat exchangers, and the cost is much higher than that of ordinary multi-connected air conditioners, which is not conducive to market promotion and application. In addition, heating is achieved through the condenser, and the comfort is not high.

[0003] The above information disclosed in this background art is only used to increase the understanding of the background art of this application. Therefore, it may include prior art that is not known to those of ordinary skill in the art. Summary of the Invention

[0004] In view of the problems pointed out in the background art, the present invention provides a multi-connected air conditioner, which recovers the condensation waste heat by setting a water-fluorine heat exchanger on the outdoor side, applies it to indoor floor heating or hot water supply, and adjusts the waste heat recovery ratio by adjusting the opening degrees of the first electronic expansion valve and the second electronic expansion valve, saving costs and energy while improving the user experience.

[0005] To achieve the above invention object, the present invention adopts the following technical solutions:

[0006] In some embodiments of the present application, a multi-connected air conditioner is provided, including an outdoor side, which includes:

[0007] A compressor, which includes an exhaust port and a suction port;

[0008] A water-fluorine heat exchanger, which includes a refrigerant passage and a water passage; one end of the refrigerant passage is connected to the exhaust port, and is used for exchanging heat and condensing the refrigerant passing through the refrigerant passage with the water passing through the water passage;

[0009] An outdoor heat exchanger, one end of which is connected to the exhaust port and is in parallel with the refrigerant passage, and is used for condensing the refrigerant during the refrigeration cycle;

[0010] A first electronic expansion valve and a second electronic expansion valve, which are respectively connected in series with the outdoor heat exchanger and the refrigerant passage, and are respectively used for controlling the refrigerant flow rates through the outdoor heat exchanger and the refrigerant passage;

[0011] An outdoor ambient temperature sensor, which is used for detecting the outdoor ambient temperature;

[0012] A controller connected to the first electronic expansion valve, the second electronic expansion valve, and the outdoor ambient temperature sensor, which is configured with a hot water mode, and in the hot water mode, receives the outdoor ambient temperature and controls the opening degrees of the first electronic expansion valve and the second electronic expansion valve according to the outdoor ambient temperature.

[0013] According to some embodiments of the present application, it further includes an inlet water temperature sensor, which is arranged near the inlet of the water passage and electrically connected to the controller for detecting the inlet water temperature and transmitting it to the controller; the controller is further configured with a first ambient reference temperature and a second ambient reference temperature less than the first ambient reference temperature;

[0014] It further includes an exhaust pressure sensor, which is arranged near the exhaust port and connected to the controller for detecting the condensation pressure and transmitting it to the controller;

[0015] The controller receives the inlet water temperature, the outdoor ambient temperature, and the condensation pressure, and is configured to:

[0016] When the outdoor ambient temperature reaches the first ambient reference temperature and above, control the first electronic expansion valve to operate at full opening, and control the opening degree of the second electronic expansion valve to be the product of half of its full opening and the ratio of the outdoor ambient temperature to the inlet water temperature;

[0017] When the outdoor ambient temperature reaches the second ambient reference temperature and below, control the opening degree of the first electronic expansion valve to be half of its full opening, and control the opening degree of the second electronic expansion valve to be half of its full opening;

[0018] When the outdoor ambient temperature is between the first ambient reference temperature and the second ambient reference temperature, control the opening degrees of the first electronic expansion valve and the second electronic expansion valve according to the condensation pressure.

[0019] According to some embodiments of the present application, it further includes a hot water temperature setter, which is communicatively connected to the controller for setting the hot water temperature and transmitting it to the controller;

[0020] The controller is configured with a second hot water temperature correction value, a second hot water target condensation pressure, a third hot water target condensation pressure, and a condensation pressure correction parameter, and is configured to:

[0021] Receive the hot water temperature; the second hot water target condensation pressure is equal to the refrigerant saturation pressure corresponding to the sum of the hot water temperature and the second hot water temperature correction value;

[0022] The third hot water target condensation pressure is equal to the refrigerant saturation pressure corresponding to the hot water temperature;

[0023] Controlling the opening degrees of the first electronic expansion valve and the second electronic expansion valve according to the condensation pressure includes:

[0024] When it is determined that the condensation pressure reaches the second hot water target condensation pressure or higher, control the first electronic expansion valve to operate at full opening, and control the opening degree of the second electronic expansion valve to be the product of half of its full opening and the ratio of the outdoor ambient temperature to the inlet water temperature;

[0025] When it is determined that the condensation pressure reaches the third hot water target condensation pressure or lower, control the opening degree of the first electronic expansion valve to be half of its full opening, and control the opening degree of the second electronic expansion valve to be half of its full opening;

[0026] When it is determined that the condensation pressure is between the second hot water target condensation pressure and the third hot water target condensation pressure, the condensation pressure correction parameter is equal to the ratio of the difference between the condensation pressure and the third hot water target condensation pressure to the difference between the second hot water target condensation pressure and the third hot water target condensation pressure; control the opening degree of the first electronic expansion valve to be equal to the sum of half of its full opening and the condensation pressure correction parameter multiplied by its full opening; control the opening degree of the second electronic expansion valve to be equal to the difference between half of its full opening and the condensation pressure correction parameter multiplied by its full opening.

[0027] According to some embodiments of the present application, it further includes an outlet water temperature sensor, which is electrically connected to the controller and is used to obtain the outlet water temperature of the water-fluorine heat exchanger and transmit it to the controller;

[0028] The controller is further configured with a first hot water temperature correction value and a first hot water target condensation pressure, and its configuration further includes:

[0029] The first hot water target condensation pressure is equal to the refrigerant saturation pressure corresponding to the sum of the outlet water temperature and the first hot water temperature correction value;

[0030] In the hot water mode, the compressor control modes include a frequency increase control mode, a frequency decrease control mode, and a frequency holding operation mode;

[0031] When the condensation pressure reaches the smaller of the first hot water target condensation pressure and the third hot water target condensation pressure or lower, the compressor operates in the frequency increase control mode; when the compressor is in the frequency increase control mode and the condensation pressure reaches the larger of the first hot water target condensation pressure and the third hot water target condensation pressure or higher, the compressor switches to the frequency holding operation mode;

[0032] When the condensation pressure reaches the second hot water target condensation pressure or above, the compressor operates in the frequency reduction control mode; when the compressor is in the frequency reduction control mode and the condensation pressure reaches the larger value of the first hot water target condensation pressure and the third hot water target condensation pressure and below, the compressor switches to the frequency holding operation mode;

[0033] When the compressor is in the frequency holding operation mode and the condensation pressure reaches the second hot water target condensation pressure or above, the compressor switches to the frequency reduction control mode; when the compressor is in the frequency holding operation mode and the condensation pressure reaches the smaller value of the first hot water target condensation pressure and the third hot water target condensation pressure and below, the compressor switches to the frequency increase control mode.

[0034] According to some embodiments of the present application, the configuration of the controller further includes:

[0035] Compare the outlet water temperature with the hot water temperature; when the outlet water temperature reaches the hot water temperature or above, control the second electronic expansion valve to close; when the outlet water temperature reaches the hot water temperature or below, operate the hot water mode.

[0036] According to some embodiments of the present application, it further includes an outdoor fan, which is electrically connected to the controller and controlled by the controller, and is arranged corresponding to the outdoor heat exchanger;

[0037] The controller is configured to control the speed of the outdoor fan to increase or decrease when operating the hot water mode so that the condensation pressure is controlled near the first hot water target condensation pressure.

[0038] According to some embodiments of the present application, it further includes:

[0039] A temperature acquisition module, which is electrically connected to the controller, is used to acquire the temperature of the controller, denoted as the control temperature, and transmit it to the controller;

[0040] The controller is further configured with a first condensation pressure correction value, a second condensation pressure correction value greater than the first condensation pressure correction value, a first control temperature threshold, and a second control temperature threshold greater than the first control temperature threshold;

[0041] The configuration of the controller further includes:

[0042] In the hot water mode, the controller receives the control temperature; and when it is determined that the control temperature reaches below the first control temperature threshold, the first hot water target condensing pressure is corrected by subtracting the first condensing pressure correction value; when the first hot water target condensing pressure is corrected by subtracting the first condensing pressure correction value and it is determined that the control temperature reaches the second control temperature threshold and above, it is changed to the first hot water target condensing pressure being corrected by subtracting the second condensing pressure correction value;

[0043] When it is determined that the control temperature reaches the second control temperature threshold and above, the first hot water target condensing pressure is corrected by subtracting the second condensing pressure correction value; when the first hot water target condensing pressure is corrected by subtracting the second condensing pressure correction value and it is determined that the control temperature reaches the first control temperature threshold and below, it is changed to the first hot water target condensing pressure being corrected by subtracting the first condensing pressure correction value.

[0044] According to some embodiments of the present application, the configuration of the controller further includes:

[0045] A condensing pressure allowable threshold;

[0046] When the first hot water target condensing pressure reaches the maximum value of the condensing pressure allowable threshold and above, the first hot water target condensing pressure is equal to the maximum value of the condensing pressure allowable threshold;

[0047] When the first hot water target condensing pressure reaches the minimum value of the condensing pressure allowable threshold and below, the first hot water target condensing pressure is equal to the minimum value of the condensing pressure allowable threshold.

[0048] According to some embodiments of the present application, the controller is further configured with a no hot water demand mode and a no hot water target condensing pressure;

[0049] The controller is further configured to, in the no hot water demand mode, receive the condensing pressure and control the outdoor fan speed to increase or decrease so that the condensing pressure is controlled near the no hot water target condensing pressure.

[0050] The configuration of the controller further includes: in the hot water mode, when the first hot water target condensing pressure does not exceed the no hot water target condensing pressure, the first hot water target condensing pressure is equal to the no hot water target condensing pressure.

[0051] According to some embodiments of the present application, the first condensing pressure correction value is 0 Mpa; the second condensing pressure correction value is 0.3 MPa; the first control temperature threshold is 63 °C, and the second control temperature threshold is 65 °C;

[0052] The set allowable threshold value of the condensation pressure is between 2.4 MPa and 3.4 MPa;

[0053] Both the first hot water temperature correction value and the second hot water temperature correction value are set to 6°C.

[0054] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0055] In the present invention, a refrigerant pipeline is led out from the exhaust side of the compressor to the water-fluorine heat exchanger, so that in any operating mode, the water-fluorine heat exchanger is on the high-pressure side, and hot water can be generated in the water path of the water-fluorine heat exchanger; moreover, by controlling the opening degrees of the first electronic expansion valve and the second electronic expansion valve, the proportion and efficiency of condensation heat recovery are adjusted; when dehumidifying / refrigerating, the condensation waste heat generated during the refrigeration process can be obtained and delivered to the room in need of heat, realizing the functions of simultaneously refrigerating and heating (without dehumidifying while lowering the temperature) in the same room, and simultaneously refrigerating or heating in different rooms or producing domestic hot water while refrigerating. The cost is reduced, energy is saved, and the user experience is improved.

[0056] After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become clearer. Brief Description of the Drawings

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for use in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other accompanying drawings can be obtained based on these drawings without creative efforts.

[0058] Figure 1 It is a schematic structural diagram of the outdoor side system according to the embodiment;

[0059] Figure 2 It is a schematic control connection diagram according to the embodiment;

[0060] Figure 3 It is a schematic diagram of the hot water mode control flow according to the embodiment;

[0061] Figure 4 It is a schematic diagram of the hot water mode control flow according to the embodiment;

[0062] Figure 5 It is a schematic diagram of the first hot water target condensation pressure acquisition flow according to the embodiment;

[0063] Figure 6 It is a schematic diagram of the control temperature correction according to the embodiment;

[0064] Figure 7Schematic diagram of the process for obtaining the first hot water target condensation pressure according to an embodiment;

[0065] Figure 8 Schematic diagram of the process for obtaining the first hot water target condensation pressure according to an embodiment;

[0066] Figure 9 Schematic diagram of the compressor frequency control process according to an embodiment;

[0067] Figure 10 Schematic diagram of the electronic expansion valve opening control process according to an embodiment;

[0068] Figure 11 Schematic diagram of the electronic expansion valve opening control process according to an embodiment.

[0069] Reference numerals:

[0070] 1. Compressor; 2. Water - fluorine heat exchanger; 3. Outdoor heat exchanger; 4. First electronic expansion valve; 5. Second electronic expansion valve; 6. Four - way valve; 7. Exhaust pressure sensor; 8. Outlet water temperature sensor; 9. Inlet water temperature sensor; 10. Outdoor fan; 20. Controller; 30. Hot water temperature setter; 40. Outdoor ambient temperature sensor; 50. Water pump; 11. Exhaust port; 12. Suction port; 21. Refrigerant passage; 22. Water passage;

[0071] Cfin1. First condensation pressure correction value; Cfin2. Second condensation pressure correction value; Tfin1. First control temperature threshold; Tfin2. Second control temperature threshold; Pdo. First hot water target condensation pressure; Pds. Second hot water target condensation pressure; Pdc. Third hot water target condensation pressure; P1. Minimum value of the condensation pressure allowable threshold; P2. Maximum value of the condensation pressure allowable threshold; Two. Outlet water temperature; Tws. Hot water temperature; Twi. Inlet water temperature; Ta. Outdoor ambient temperature; Ta1. First ambient reference temperature; Ta2. Second ambient reference temperature; Pd. Condensation pressure; Evo. First electronic expansion valve opening; Evw. Second electronic expansion valve opening. Embodiment

[0072] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0073] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0074] The terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0075] In the description of the present application, it should be noted that, unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" should be construed broadly. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0076] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0077] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity, and does not 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 of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0078] An air conditioner performs a refrigeration cycle of the air conditioner by using a compressor, a condenser, an expansion valve, and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation to cool or heat an indoor space.

[0079] A low-temperature and low-pressure refrigerant enters the compressor, and the compressor compresses it into a refrigerant gas in a high-temperature and high-pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process.

[0080] The expansion valve expands the high-temperature and high-pressure liquid-phase refrigerant formed by condensation in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a refrigeration effect by using the latent heat of evaporation of the refrigerant to exchange heat with the material to be cooled. Throughout the cycle, the air conditioner can adjust the temperature of the indoor space.

[0081] The outdoor unit of the air conditioner refers to the part of the refrigeration cycle including the compressor and the outdoor heat exchanger. The indoor unit of the air conditioner includes an indoor heat exchanger, and the expansion valve can be provided in the indoor unit or the outdoor unit.

[0082] The indoor heat exchanger and the outdoor heat exchanger serve as condensers or evaporators. When the indoor heat exchanger serves as a condenser, the air conditioner serves as a heater in the heating mode. When the indoor heat exchanger serves as an evaporator, the air conditioner serves as a cooler in the cooling mode.

[0083] In a specific embodiment, referring to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , the multi-connected air conditioner of the present invention includes an outdoor side and an indoor side; the indoor side includes an indoor heat exchanger, a floor heating or a hot water tank; the outdoor side includes a compressor 1, a water-fluorine heat exchanger 2, and an outdoor heat exchanger 3; the compressor 1 includes an exhaust port 11 and a suction port 12; the water-fluorine heat exchanger 2 includes a refrigerant passage 21 and a water passage 22; the refrigerant passages 21 of the outdoor heat exchanger 3 and the water-fluorine heat exchanger 2 are connected in parallel, and one end is commonly connected to the exhaust port 11 of the compressor 1, and the other end is connected to the indoor heat exchanger on the indoor side; the floor heating or the hot water tank is connected to the water passage 22 of the water-fluorine heat exchanger 2, and floor heating or hot water supply is realized by recovering the heat of condensing the refrigerant in the refrigerant passage 21.

[0084] The multi-connected air conditioner further includes an exhaust pressure sensor 7, an outdoor fan 10, a water outlet temperature sensor 8, and a controller 20 electrically connected to the exhaust pressure sensor 7, the outdoor fan 10, and the water outlet temperature sensor 8 respectively.

[0085] The exhaust pressure sensor 7, the outdoor fan 10, and the water outlet temperature sensor 8 are respectively located inside the outdoor side; the exhaust pressure sensor 7 is arranged near the exhaust port 11 of the compressor 1 for detecting the exhaust pressure of the exhaust port 11 of the compressor 1; that is, detecting the condensation pressure Pd of the multi-split air-conditioning system. The outdoor fan 10 is arranged corresponding to the outdoor heat exchanger 3 for accelerating the air flow inside and around the outdoor heat exchanger 3 and accelerating the heat exchange between the outdoor heat exchanger 3 and the surrounding air. The water outlet temperature sensor 8 is arranged near the water outlet of the water passage 22 for detecting the temperature of the water outlet of the water passage 22 of the water-fluorine heat exchanger 2; that is, detecting the water outlet temperature Two of the water-fluorine heat exchanger 2.

[0086] The controller 20 is configured with a hot water mode, which operates under the refrigeration cycle of the multi-split air-conditioning. That is, when the multi-split air-conditioning operates in the refrigeration mode or the dehumidification mode, the hot water mode can be operated to make the water-fluorine heat exchanger 2 work, recover heat during the condensation process, and provide circulating hot water for the floor heating of the indoor room or hot water for the hot water tank.

[0087] The configuration of the controller 20 further includes: when operating the hot water mode, receiving the water outlet temperature Two detected by the water outlet temperature sensor 8 and the condensation pressure Pd detected by the exhaust pressure sensor 7; setting the first hot water target condensation pressure Pdo according to the water outlet temperature Two; controlling the speed of the outdoor fan 10 to increase or decrease so that the condensation pressure Pd is controlled near the first hot water target condensation pressure Pdo.

[0088] Specifically, when the condensation pressure Pd reaches and is higher than the first hot water target condensation pressure Pdo, the speed of the outdoor fan 10 is controlled to increase, the heat exchange of the outdoor heat exchanger 3 is strengthened, the condensation pressure Pd of the multi-split air-conditioning system is reduced, and further the condensation pressure Pd of the refrigerant in the refrigerant passage 21 of the water-fluorine heat exchanger 2 is reduced, and the condensation temperature of the refrigerant in the refrigerant passage 21 is reduced; when the condensation pressure Pd reaches and is lower than the first hot water target condensation pressure Pdo, the speed of the outdoor fan 10 is controlled to decrease, the heat exchange of the outdoor heat exchanger 3 is weakened, the condensation pressure Pd of the multi-split air-conditioning system is increased, and further the condensation pressure of the refrigerant in the refrigerant passage 21 of the water-fluorine heat exchanger 2 is increased, and the condensation temperature of the refrigerant in the refrigerant passage 21 is increased, so as to achieve the purpose of adjusting the condensation pressure Pd of the multi-split air-conditioning system and the condensation pressure Pd of the refrigerant in the refrigerant passage 21 by controlling the speed of the outdoor fan 10 and then adjusting the hot water temperature Tws of the heat recovery.

[0089] The multi-connected air conditioner of this embodiment sets the hot water mode, and in the hot water mode, sets the first hot water target condensation pressure Pdo according to the outlet water temperature Two, and controls the rotation speed of the outdoor fan 10 to keep the condensation pressure Pd of the system near the first hot water target condensation pressure Pdo, so as to gradually increase the outlet water temperature Two of the water-fluorine heat exchanger 2 to the required height, ensure the supply of high-temperature hot water, and improve the user experience.

[0090] In a specific embodiment, referring to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 ,the controller is also configured with a first hot water temperature correction value; the first hot water target condensation pressure Pdo is equal to the refrigerant saturation pressure corresponding to the sum of the outlet water temperature Two and the first hot water temperature correction value.

[0091] The multi-connected air conditioner of this embodiment sets the first hot water temperature correction value to make the first hot water target condensation pressure Pdo higher than the refrigerant saturation pressure corresponding to the outlet water temperature Two, so that the target condensation temperature of the refrigerant in the refrigerant passage 21 of the water-fluorine heat exchanger 2 is higher than the outlet water temperature Two, ensuring that the outlet water temperature Two of the water passage 22 gradually increases to the required high water temperature through the condensation effect of the water-fluorine heat exchanger 2 by setting the first hot water target condensation pressure Pdo, and ensuring the supply of high-temperature hot water by the water-fluorine heat exchanger 2.

[0092] In an embodiment, referring to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 ,the controller 20 is also configured with a no-hot-water demand mode; that is, when the no-hot-water demand mode is running, the multi-connected air conditioner has no floor heating supply for any indoor unit or no hot water supply for any hot water tank. At this time, the multi-connected air conditioner simply runs in the cooling mode or the dehumidification mode.

[0093] The controller 20 is also configured with a no-hot-water target condensation pressure; when the no-hot-water demand mode is running, the controller 20 receives the condensation pressure Pd detected by the exhaust pressure sensor 7, and controls the rotation speed of the outdoor fan 10 to increase or decrease according to the received value of the condensation pressure Pd, so as to keep the condensation pressure Pd near the no-hot-water target condensation pressure.

[0094] Specifically, when the condensation pressure Pd reaches the no-hot-water target condensation pressure or above, the rotation speed of the outdoor fan 10 is controlled to increase, enhancing the heat exchange of the outdoor heat exchanger 3 to reduce the condensation pressure Pd of the multi-split air-conditioning system; when the condensation pressure Pd reaches the no-hot-water target condensation pressure or below, the rotation speed of the outdoor fan 10 is controlled to decrease, weakening the heat exchange of the outdoor heat exchanger to increase the condensation pressure Pd of the multi-split air-conditioning system. The pressure of the multi-split air-conditioning system is maintained within a normal and efficient range.

[0095] In one embodiment, referring to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 8 ,the multi-split also includes a heat dissipation module, an electrical system, and a first temperature acquisition module; the heat dissipation module is used to dissipate heat from the electrical system; and the outdoor fan 10 simultaneously dissipates heat from the heat dissipation module; to ensure the normal operation of the electrical system, it is necessary to ensure the rotation speed of the outdoor fan 10 and the heat dissipation effect of the heat dissipation module.

[0096] The controller 20 is included in the electrical system, and its temperature is the control temperature, which needs to be monitored closely to ensure the normal operation of the controller 20. The first temperature acquisition module is used to acquire the control temperature, which can be built into the controller 20 or set outside the controller 20, and transmit the acquired control temperature to the controller 20.

[0097] The controller 20 is also configured with a first condensation pressure correction value Cfin1, a second condensation pressure correction value Cfin2 greater than the first condensation pressure correction value Cfin1, a first control temperature threshold Tfin1, and a second control temperature threshold Tfin2 greater than the first control temperature threshold Tfin1.

[0098] The configuration of the controller 20 also includes:

[0099] The correction of the first hot-water target condensation pressure Pdo includes correcting the first hot-water target condensation pressure Pdo by subtracting the first condensation pressure correction value Cfin1 and correcting the first hot-water target condensation pressure Pdo by subtracting the second condensation pressure correction value Cfin2; and the first hot-water target condensation pressure Pdo in both the correction of the first hot-water target condensation pressure Pdo by subtracting the first condensation pressure correction value Cfin1 and the correction of the first hot-water target condensation pressure Pdo by subtracting the second condensation pressure correction value Cfin2 is the original value of the first hot-water target condensation pressure Pdo before correction.

[0100] In the hot water mode, the controller 20 receives the control temperature obtained by the first temperature acquisition module and judges it. When the control temperature reaches the first control temperature threshold Tfin1 and is below it, the first hot water target condensation pressure Pdo is corrected by subtracting the first condensation pressure correction value Cfin1; when the first hot water target condensation pressure Pdo remains corrected by subtracting the first condensation pressure correction value Cfin1 and the control temperature reaches the second control temperature threshold Tfin2 and is above it, the first hot water target condensation pressure Pdo is changed to be corrected by subtracting the second condensation pressure correction value Cfin2.

[0101] When the control temperature reaches the second control temperature threshold Tfin2 and is above it, the first hot water target condensation pressure Pdo is corrected by subtracting the second condensation pressure correction value Cfin2; when the first hot water target condensation pressure Pdo is in the state of being corrected by subtracting the second condensation pressure correction value Cfin2 and the control temperature reaches the first control temperature threshold Tfin1 and is below it, the first hot water target condensation pressure Pdo is changed to be corrected by subtracting the first condensation pressure correction value Cfin1.

[0102] The multi-connected air conditioner of this embodiment corrects the first hot water target condensation pressure Pdo to different degrees at different temperatures by the controller 20, ensuring that when the fan speed is reduced to increase the condensation pressure Pd, it does not affect the heat dissipation of the electrical system by the heat dissipation module, especially the heat dissipation of the controller 20, ensuring the normal operation of the electrical system, improving the hot water supply temperature and ensuring the reliability of the system operation at the same time.

[0103] In addition, it should be noted that the correction of the first hot water target condensation pressure Pdo starts to run by subtracting the first condensation pressure correction value Cfin1.

[0104] In a specific embodiment, referring to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 ,the controller 20 is also configured with a condensation pressure allowable threshold; and the configuration of the controller 20 also includes:

[0105] When the first hot water target condensation pressure Pdo exceeds the maximum value P2 of the condensation pressure allowable threshold, the first hot water target condensation pressure Pdo is equal to the maximum value P2 of the condensation pressure allowable threshold; when the first hot water target pressure is lower than the minimum value P1 of the condensation pressure allowable threshold, the first hot water target condensation pressure Pdo is equal to the minimum value P1 of the condensation pressure allowable threshold.

[0106] The multi-connected air conditioner of this embodiment ensures the normal pressure of the multi-connected air conditioner system by setting a condensation pressure allowable threshold and comparing the first hot water target condensation pressure Pdo with the condensation pressure allowable threshold, so that the first hot water target condensation pressure Pdo is within the range of the condensation pressure allowable threshold, thereby ensuring the reliability and efficiency of the operation of the multi-connected air conditioner system.

[0107] In a specific embodiment, referring to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 7 , the configuration of the controller 20 further includes:

[0108] In the hot water mode, after the first hot water target condensation pressure Pdo is corrected by the first condensation pressure correction value Cfin1 or the second condensation pressure correction value Cfin2 and / or judged by the condensation pressure allowable threshold and then compared with the no-hot water target condensation pressure, when the first hot water target condensation pressure Pdo does not exceed the no-hot water target condensation pressure upwards, the first hot water target condensation pressure Pdo is equal to the no-hot water target condensation pressure. Of course, when the first hot water target condensation pressure Pdo exceeds the no-hot water target condensation pressure upwards, the controller 20 controls using the original value or the corrected value of the first hot water target condensation pressure Pdo.

[0109] The multi-connected air conditioner of this embodiment prevents the condensation pressure Pd of the multi-connected air conditioner system from being too low when the set outlet water temperature Two is too low, which affects the efficiency of the multi-connected air conditioner system.

[0110] In a specific embodiment, the value range of the first hot water temperature correction value is 4 to 7 °C; the first hot water temperature correction value is preferably 6 °C.

[0111] In a specific embodiment, the first condensation pressure correction value Cfin1 is 0 MPa; the second condensation pressure correction value Cfin2 is 0.3 MPa; the first control temperature threshold Tfin1 and the second control temperature threshold Tfin2 are respectively temperature points, rather than temperature ranges; preferably, the first control temperature threshold Tfin1 is 63 °C; the second control temperature threshold Tfin2 is 65 °C. Of course, the first control temperature threshold Tfin1 and the second control temperature threshold Tfin2 can also be set to other appropriate values according to the working temperature of the controller; the first condensation pressure correction value Cfin1 and the second condensation pressure correction value Cfin2 can also be set to appropriate values according to the refrigerant system operation pressure of the multi-connected air conditioner system.

[0112] In a specific embodiment, the condensation pressure allowable threshold is between 2.4 MPa and 3.4 MPa.

[0113] In a specific embodiment, referring to Figure 1 、Figure 2 , Figure 3 , Figure 4 , Figure 5 , the outdoor side of the multi-connected air conditioner further includes a four-way valve 6; one end of the outdoor heat exchanger 3 is connected to the exhaust port 11 of the compressor 1 through the connection of both ends of the four-way valve 6, and is connected to the suction port 12 of the compressor 1 through the connection of the other two ends of the four-way valve 6; the four-way valve 6 is electrically connected to the controller 20 and is controlled by the controller 20.

[0114] When the multi-connected air conditioner system is in the refrigeration cycle, the four-way valve 6 is closed, and one end of the outdoor heat exchanger 3 is connected to the exhaust port 11 through the four-way valve 6; one end of the refrigerant passage 21 of the water-fluorine heat exchanger 2 is connected to the exhaust port 11, ensuring that one end of the water-fluorine heat exchanger 2 is always connected to the exhaust port 11, realizing the recovery of the condensation heat in the refrigeration mode and the dehumidification mode. When the four-way valve 6 is controlled to open, one end of the outdoor heat exchanger 3 is connected to the suction port 12 through the four-way valve 6, then the refrigerant is discharged from the exhaust port 11 and enters the water-fluorine heat exchanger 2; after passing through the refrigerant passage 21 of the water-fluorine heat exchanger 2, it enters the outdoor heat exchanger 3; then it enters the compressor 1 from the suction port 12 through the outdoor heat exchanger 3, realizing the pure floor heating mode of the water-fluorine heat exchanger 2 for separate condensation heat release and the outdoor heat exchanger 3 for evaporation heat absorption.

[0115] The multi-connected air conditioner of this embodiment realizes the heat recovery in the refrigeration mode and the dehumidification mode and the floor heating mode through the control of the four-way valve 6; in addition, during the dehumidification mode, heat recovery floor heating can be used for heating, realizing the effect of dehumidification without temperature drop, improving the comfort of users, and thus enhancing the user experience.

[0116] In some specific embodiments, referring to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 9 , the multi-connected air conditioner further includes a hot water temperature setter 30, which is communicatively connected to the controller 20 and is used to set the hot water temperature Tws and transmit the set hot water temperature Tws to the controller; the controller 20 is also configured with a second hot water temperature correction value, a second hot water target condensation pressure Pds, and a third hot water target condensation pressure Pdc.

[0117] The configuration of the controller 20 further includes:

[0118] Judging whether to execute the hot water mode according to the comparison between the hot water temperature Tws and the outlet water temperature Two; specifically, when the outlet water temperature Two reaches the hot water temperature Tws and above, execute the simple refrigeration mode or the dehumidification mode; when the outlet water temperature Two reaches the hot water temperature Tws and below, execute the hot water mode.

[0119] In some specific embodiments, referring to Figure 1 ,Figure 2 , Figure 3 、 Figure 4 、 Figure 5 、 Figure 9 , it is possible to set whether to turn on the hot water supply through the hot water temperature setter 30, and transmit a start signal for the hot water mode to the controller 20.

[0120] In some specific embodiments, referring to Figure 1 、 Figure 2 , Figure 3 、 Figure 4 、 Figure 5 、 Figure 9 , the compressor 1 is connected to the controller 20, and the operating frequency is controlled by the controller 20. The configuration of the controller 20 further includes:

[0121] The second hot water target condensation pressure Pds is equal to the refrigerant saturation pressure corresponding to the sum of the hot water temperature Tws and the second hot water temperature correction value;

[0122] The third hot water target condensation pressure Pdc is equal to the refrigerant saturation pressure corresponding to the hot water temperature Tws;

[0123] In the hot water mode, the operating control mode of the compressor 1 includes a frequency increase control mode, a frequency decrease control mode, and a constant frequency operation mode;

[0124] Receiving the condensation pressure Pd, controlling the compressor 1 to operate in different operating control modes according to the condensation pressure Pd; specifically as follows:

[0125] When the condensation pressure Pd reaches the smaller value of the first hot water target condensation pressure Pdo and the third hot water target condensation pressure Pdc and is below it, the compressor 1 operates in the frequency increase control mode; when the compressor 1 is operating in the frequency increase control mode, if the condensation pressure Pd reaches the larger value of the first hot water target condensation pressure Pdo and the third hot water target condensation pressure Pdc and is above it, the compressor 1 switches to the constant frequency operation mode.

[0126] When the condensation pressure Pd reaches the second hot water target condensation pressure Pds and is above it, the compressor 1 operates in the frequency decrease control mode; when the compressor 1 is operating in the frequency decrease control mode and the condensation pressure Pd reaches the larger value of the first hot water target condensation pressure Pdo and the third hot water target condensation pressure Pdc and is below it, the compressor 1 switches to the constant frequency operation mode.

[0127] When the compressor 1 is operating in the constant frequency operation mode, if the condensation pressure Pd reaches the second hot water target condensation pressure Pds and above, the compressor 1 switches to the frequency decrease control mode; when the condensation pressure Pd reaches the smaller value of the first hot water target condensation pressure Pdo and the third hot water target condensation pressure Pdc and is below it, the compressor 1 switches to the frequency increase control mode.

[0128] The multi-connected air conditioner in this embodiment controls the operating frequency of the compressor 1 through the condensing pressure Pd, so that it adapts to the power of the multi-connected air conditioner system corresponding to the condensing pressure Pd, and reduces power consumption.

[0129] In addition, it should be noted that the frequency operation control of the compressor 1 starts from the frequency increase control mode.

[0130] In a specific embodiment, referring to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 10 、 Figure 11 The outdoor side of the multi-connected air conditioner further includes a first electronic expansion valve 4 and a second electronic expansion valve 5, which are respectively connected in series with the outdoor heat exchanger 3 and the refrigerant passage 21, and are located at one end of the outdoor heat exchanger 3 and the refrigerant passage 21 far from the exhaust port 11; one end of the first electronic expansion valve 4 and one end of the second electronic expansion valve 5 are connected and then connected to the indoor heat exchanger, respectively used to control the refrigerant flow through the outdoor heat exchanger 3 and the refrigerant passage 21.

[0131] The outdoor side of the multi-connected air conditioner further includes an outdoor ambient temperature sensor 40, which is arranged outdoors and electrically connected to the controller 20, and is used to detect the outdoor ambient temperature Ta and transmit it to the controller 20.

[0132] The outdoor side of the multi-connected air conditioner further includes a water pump 50, which is connected in series with the water passage 22 and connected to the controller 20, and is controlled by the controller 20; when the hot water mode is started, the water pump 50 is controlled to operate to circulate the water in the water passage 22.

[0133] The configuration of the controller 20 further includes:

[0134] In the hot water mode, receive the outdoor ambient temperature Ta, and control the opening degrees of the first electronic expansion valve 4 and the second electronic expansion valve 5 according to the outdoor ambient temperature Ta.

[0135] The multi-connected air conditioner in this embodiment leads a refrigerant pipeline from the exhaust side of the compressor 1 to the water-fluorine heat exchanger 2, so that in any operating mode, the water-fluorine heat exchanger 2 is in the high-pressure side, the water passage 22 of the water-fluorine heat exchanger 2 can generate hot water, and the proportion and efficiency of the condensing heat recovery are adjusted by controlling the opening degrees of the first electronic expansion valve 4 and the second electronic expansion valve 5 according to the outdoor ambient temperature; when dehumidifying / refrigerating, obtain the condensing waste heat generated during the refrigeration process, transport it to the room that needs heat, and realize the functions of cooling and heating in the same room at the same time (without cooling and dehumidifying), and cooling or heating in different rooms at the same time or producing domestic hot water while refrigerating. Reduce costs, save energy, and improve the user experience.

[0136] In a specific embodiment, referring to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 10 , Figure 11 , the multi-connected air conditioner further includes a first electronic expansion valve 4 and a second electronic expansion valve 5, which are respectively connected in series to one end of the outdoor heat exchanger 3 away from the exhaust port 11 of the compressor 1 and one end of the refrigerant passage 21 of the water-fluorine heat exchanger 2 away from the exhaust port 11 of the compressor 1, and are respectively electrically connected to the controller 20. The controller 20 controls their opening degrees to adjust the flow rate of the high-temperature and high-pressure refrigerant entering the outdoor heat exchanger 3 and the water-fluorine heat exchanger 2, and further adjusts the proportion of waste heat recovery.

[0137] The other end of the outdoor heat exchanger 3 and the other end of the refrigerant passage 21 of the water-fluorine heat exchanger 2 are respectively connected to the indoor heat exchanger through the first electronic expansion valve 4 and the second electronic expansion valve 5, and respectively throttle and depressurize the refrigerant discharged from the exhaust port 11 of the compressor 1 through the outdoor heat exchanger 3 and the refrigerant passage 21. When the four-way valve 6 is opened, the refrigerant discharged from the exhaust port 11 passes through the refrigerant passage 21 and is successively throttled and depressurized by the first electronic expansion valve 4 and the second electronic expansion valve 5 and then enters the outdoor heat exchanger 3 and returns to the compressor 1, instead of entering the indoor heat exchanger.

[0138] The outdoor side of the multi-connected air conditioner further includes a water inlet temperature sensor 9, which is arranged near the water inlet of the water passage 22 and is electrically connected to the controller 20 for detecting the water inlet temperature Twi and transmitting it to the controller 20.

[0139] The controller 20 is configured with a first ambient reference temperature Ta1 and a second ambient reference temperature Ta2 lower than the first ambient reference temperature Ta1;

[0140] The controller 20 is further configured that in the hot water mode, it receives the hot water temperature Tws set by the hot water temperature setter 30; determines whether the outlet water temperature Two reaches the hot water temperature Tws. If not, it starts the hot water mode operation; if the outlet water temperature Two reaches the set hot water temperature Tws, it only operates in the cooling mode or the dehumidification mode. At this time, the controller 20 controls the second electronic expansion valve 5 to close.

[0141] When the hot water mode operation is performed, it is determined whether the outdoor ambient temperature Ta reaches the first ambient reference temperature Ta1 and above; if so, it controls the first electronic expansion valve 4 to the maximum opening degree; controls the opening degree of the second electronic expansion valve 5 to half of the maximum opening degree and corrects it by using the ratio of the outdoor ambient temperature Ta and the water inlet temperature Twi of the water-fluorine heat exchanger 2 as a coefficient.

[0142] Specifically, the opening degree of the second electronic expansion valve 5 is half of the maximum opening degree multiplied by the ratio of the outdoor ambient temperature Ta to the inlet water temperature Twi of the water-fluorine heat exchanger 2. It is expressed by the formula:

[0143] Evw = 0.5×Evwmax (Ta / Twi);

[0144] In the formula,

[0145] Evw is the opening degree of the second electronic expansion valve;

[0146] Evwmax is the maximum opening degree of the second electronic expansion valve;

[0147] Ta is the outdoor ambient temperature;

[0148] Twi is the inlet water temperature of the water passage.

[0149] When the outdoor temperature of the multi-connected air conditioner in this embodiment reaches the first environmental reference temperature Ta1 and above, the first environmental reference temperature Ta1 is set as a relatively high outdoor ambient temperature Ta. At this time, the exhaust pressure of the multi-connected air conditioner unit during operation is relatively high due to the influence of the high outdoor ambient temperature, and the generated condensation heat is relatively large. At this time, by opening the first electronic expansion valve 4 to the maximum, the heat exchange amount of the outdoor heat exchanger 3 is increased to ensure the refrigeration effect of the unit.

[0150] The opening degree of the second electronic expansion valve 5 is directly proportional to the outdoor ambient temperature Ta and inversely proportional to the inlet water temperature Twi; that is, when the outdoor ambient temperature Ta is relatively high and the exhaust pressure (condensation pressure Pd) is relatively large, the opening degree of the second electronic expansion valve 5 is increased according to the proportion of the outdoor ambient temperature Ta to increase the flow rate of the refrigerant passing through the refrigerant passage 21 and increase the condensation heat recovery amount; vice versa. As the inlet water temperature Twi of the water passage 22 increases, the opening degree is reduced according to the proportion of the inlet water temperature Twi to prevent the outlet water temperature Two in the water passage 22 from being too high and affecting the condensation efficiency. As the inlet water temperature Twi of the water passage 22 decreases, the opening degree is increased according to the proportion of the inlet water temperature Twi to increase the heat recovery amount; and to prevent the refrigerant passing through the second electronic expansion valve 5 from being in a two-phase state and affecting the refrigeration effect.

[0151] The controller 20 is also configured with a condensation pressure correction parameter, and the controller 20 is further configured to set the opening degrees of the first electronic expansion valve 4 and the second electronic expansion valve 5 according to the relationship between the condensation pressure Pd and the second hot water target condensation pressure Pds and the third hot water target condensation pressure Pdc when the outdoor ambient temperature Ta is between the first environmental reference temperature Ta1 and the second environmental reference temperature Ta2.

[0152] Specifically, it includes:

[0153] When the condensation pressure Pd reaches the second hot water target condensation pressure Pds or above, the first electronic expansion valve 4 operates at its maximum opening; the opening of the second electronic expansion valve 5 is half of its maximum opening multiplied by the ratio of the outdoor ambient temperature Ta to the inlet water temperature of the water-fluorine heat exchanger 2.

[0154] At this time, the multi-connected air conditioner unit is in a suitable outdoor ambient temperature Ta, and the refrigeration capacity is relatively sufficient; if the system condensation pressure Pd is relatively high at this time, there will be a situation where the condensation pressure Pd exceeds the first hot water target condensation pressure Pdo, resulting in a decrease in the refrigeration effect; to ensure the refrigeration effect, when the condensation pressure Pd reaches and exceeds the second hot water target condensation pressure Pds, the first electronic expansion valve 4 operates at its maximum opening to increase the heat exchange amount of the outdoor heat exchanger 3 and ensure the refrigeration effect; the opening of the second electronic expansion valve 5 is half of its maximum opening multiplied by the ratio of the outdoor ambient temperature Ta to the inlet water temperature Twi of the water-fluorine heat exchanger 2; the opening of the second electronic expansion valve 5 is adjusted according to the outdoor ambient temperature Ta and the inlet water temperature Twi to prevent the refrigerant passing through the second electronic expansion valve 5 from being in a two-phase state and affecting the refrigeration effect.

[0155] When the condensation pressure Pd is between the third hot water target condensation pressure Pdc and the second hot water target condensation pressure Pds, the opening of the first electronic expansion valve 4 is the sum of half of its maximum opening and its maximum opening corrected with the ratio of the difference between the condensation pressure Pd and the third hot water target condensation pressure Pdc to the difference between the second hot water target condensation pressure Pds and the third hot water target condensation pressure Pdc as the proportionality coefficient; the opening of the second electronic expansion valve 5 is the difference between half of its maximum opening and its maximum opening corrected with the ratio of the difference between the condensation pressure Pd and the third hot water target condensation pressure Pdc to the difference between the second hot water target condensation pressure Pds and the third hot water target condensation pressure Pdc as the proportionality coefficient. That is to say, the condensation pressure correction parameter is equal to the ratio of the difference between the condensation pressure Pd and the third hot water target condensation pressure Pdc to the difference between the second hot water target condensation pressure Pds and the third hot water target condensation pressure Pdc; controlling the opening of the first electronic expansion valve 4 is equal to the sum of half of its fully open degree and the condensation pressure correction parameter multiplied by its fully open degree; controlling the opening of the second electronic expansion valve 5 is equal to the difference between half of its fully open degree and the condensation pressure correction parameter multiplied by its fully open degree.

[0156] That is, the opening of the first electronic expansion valve 4 is equal to the value obtained by multiplying its maximum opening by the ratio of the difference between the condensation pressure Pd and the third hot water target condensation pressure Pdc to the difference between the second hot water target condensation pressure Pds and the third hot water target condensation pressure Pdc plus half of the maximum opening of the first electronic expansion valve 4; the opening of the second electronic expansion valve 5 is equal to half of its maximum opening minus the value obtained by multiplying its maximum opening by the ratio of the difference between the condensation pressure Pd and the third hot water target condensation pressure Pdc to the difference between the second hot water target condensation pressure Pds and the third hot water target condensation pressure Pdc.

[0157] That is, EVo = (0.5 + (Pd - Pdc) / (Pds - Pdc)) × EVomax;

[0158] EVw = (0.5 - (Pd - Pdc) / (Pds - Pdc)) × EVwmax;

[0159] Wherein,

[0160] EVo is the opening degree of the first electronic expansion valve;

[0161] EVw is the opening degree of the second electronic expansion valve;

[0162] EVomax is the maximum opening degree of the first electronic expansion valve;

[0163] EVwmax is the maximum opening degree of the second electronic expansion valve;

[0164] Pd is the condensation pressure;

[0165] Pds is the second hot water target condensation pressure;

[0166] Pdc is the third hot water target condensation pressure.

[0167] During the operation of the hot water mode, only when the refrigerant condensation temperature is higher than the set hot water temperature Tws of the water temperature can the water temperature reach the hot water temperature Tws. Therefore, we introduce two parameters, the third hot water target condensation pressure Pdc and the second hot water target condensation pressure Pds; the third hot water target condensation pressure Pdc is equal to the refrigerant saturation pressure corresponding to the hot water temperature Tws; only when the actual condensation pressure Pd reaches the third hot water target condensation pressure Pdc and above, is it possible to make the water temperature reach the set hot water temperature Tws; the second hot water target condensation pressure Pds is the set maximum condensation pressure of the unit system, equal to the refrigerant saturation pressure corresponding to the sum of the set hot water temperature Tws and the second hot water temperature correction value; therefore, when the condensation pressure Pd of the multi-connected air conditioner unit system is between the third hot water target condensation pressure Pdc and the second hot water target condensation pressure Pds, by setting the parameters related to the third hot water target condensation pressure Pdc and the second hot water target condensation pressure Pds, the opening degrees of the first electronic expansion valve 4 and the second electronic expansion valve 5 are controlled to keep the pressure of the multi-connected air conditioner system stable between the third hot water target condensation pressure Pdc and the second hot water target condensation pressure Pds, improving the reliability of the condensation heat recovery.

[0168] When the condensation pressure Pd reaches the third hot water target condensation pressure Pdc and below, the first electronic expansion valve 4 operates at half of its maximum opening degree; the second electronic expansion valve 5 operates at half of its maximum opening degree.

[0169] That is, when the condensation pressure Pd of the multi-connected air conditioner unit system is less than the third hot water target condensation pressure Pdc, the system cannot reach the set hot water temperature Tws. At this time, the first electronic expansion valve 4 and the second electronic expansion valve 5 are controlled to operate at half of their maximum openings respectively, reducing the refrigerant flow rate of the outdoor heat exchanger 3 and increasing the refrigerant flow rate of the water-fluorine heat exchanger 2 to slowly increase the water temperature. As the water temperature rises, the condensation pressure Pd of the unit system will also rise to a certain extent until it reaches the third hot water target condensation pressure Pdc, and then high water temperature hot water supply control is carried out.

[0170] The controller 20 is further configured that when the outdoor ambient temperature Ta reaches the second ambient reference temperature Ta2 and below, the first electronic expansion valve 4 operates at half of its maximum opening; the second electronic expansion valve 5 operates at half of its maximum opening.

[0171] That is, when the outdoor ambient temperature Ta is low, the heat recovery effect will be poor. Even if the control of reducing the rotation speed of the outdoor fan 10 is adopted, it is difficult to reach the required exhaust pressure, that is, the condensation pressure Pd. Therefore, when the outdoor ambient temperature Ta is low, the openings of the first electronic expansion valve 4 and the second electronic expansion valve 5 are respectively fixed at half of their maximum openings to operate, maintaining the condensation pressure for the normal operation of the unit system, and improving the heat recovery effect by adjusting the rotation speed of the outdoor fan 10 to increase the condensation pressure.

[0172] Of course, in all the above stages, the condensation pressure Pd of the unit system can be accelerated to rise by synchronously adjusting the wind speed of the outdoor fan 10.

[0173] In the description of the above embodiments, the specific features, structures, materials or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0174] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A multi-connected air conditioner, characterized in that, including an outdoor side, which includes: a compressor, which includes an exhaust port and a suction port; a water-fluorine heat exchanger, which includes a refrigerant passage and a water passage; one end of the refrigerant passage is connected to the exhaust port, and is used for exchanging heat and condensing the refrigerant passing through the refrigerant passage with the water passing through the water passage; an outdoor heat exchanger, one end of which is connected to the exhaust port and is in parallel with the refrigerant passage, and is used for condensing the refrigerant during the refrigeration cycle; a first electronic expansion valve and a second electronic expansion valve, which are respectively connected in series with the outdoor heat exchanger and the refrigerant passage, and are respectively used for controlling the refrigerant flow rates passing through the outdoor heat exchanger and the refrigerant passage; an outdoor ambient temperature sensor, which is used for detecting the outdoor ambient temperature; a controller connected to the first electronic expansion valve, the second electronic expansion valve, and the outdoor ambient temperature sensor, which is configured with a hot water mode, and in the hot water mode, receives the outdoor ambient temperature and controls the opening degrees of the first electronic expansion valve and the second electronic expansion valve according to the outdoor ambient temperature; further including an inlet water temperature sensor, which is arranged near the water inlet of the water passage and is electrically connected to the controller, and is used for detecting the inlet water temperature and transmitting it to the controller; the controller is further configured with a first ambient reference temperature and a second ambient reference temperature lower than the first ambient reference temperature; further including an exhaust pressure sensor, which is arranged near the exhaust port and is connected to the controller, and is used for detecting the condensation pressure and transmitting it to the controller; the controller receives the inlet water temperature, the outdoor ambient temperature, and the condensation pressure, and is configured as follows: when the outdoor ambient temperature reaches the first ambient reference temperature and above, control the first electronic expansion valve to operate at full opening, and control the opening degree of the second electronic expansion valve to be the product of half of its full opening degree and the ratio of the outdoor ambient temperature to the inlet water temperature; when the outdoor ambient temperature reaches the second ambient reference temperature and below, control the opening degree of the first electronic expansion valve to be half of its full opening degree, and control the opening degree of the second electronic expansion valve to be half of its full opening degree; when the outdoor ambient temperature is between the first ambient reference temperature and the second ambient reference temperature, control the opening degrees of the first electronic expansion valve and the second electronic expansion valve according to the condensation pressure.

2. The multi-connected air conditioner according to claim 1, characterized in that, further including a hot water temperature setter, which is communicatively connected to the controller and is used for setting the hot water temperature and transmitting it to the controller; the controller is configured with a second hot water temperature correction value, a second hot water target condensation pressure, a third hot water target condensation pressure, and a condensation pressure correction parameter, and is configured as follows: receive the hot water temperature; the second hot water target condensation pressure is equal to the refrigerant saturation pressure corresponding to the sum of the hot water temperature and the second hot water temperature correction value; the third hot water target condensation pressure is equal to the refrigerant saturation pressure corresponding to the hot water temperature; controlling the opening degrees of the first electronic expansion valve and the second electronic expansion valve according to the condensation pressure includes: When it is determined that the condensation pressure reaches the second hot water target condensation pressure or above, control the first electronic expansion valve to operate at full opening, and control the opening degree of the second electronic expansion valve to be the product of half of its full opening degree and the ratio of the outdoor ambient temperature to the inlet water temperature; When it is determined that the condensation pressure reaches the third hot water target condensation pressure or below, control the opening degree of the first electronic expansion valve to be half of its full opening degree, and control the opening degree of the second electronic expansion valve to be half of its full opening degree; When it is determined that the condensation pressure is between the second hot water target condensation pressure and the third hot water target condensation pressure, the condensation pressure correction parameter is equal to the ratio of the difference between the condensation pressure and the third hot water target condensation pressure to the difference between the second hot water target condensation pressure and the third hot water target condensation pressure; control the opening degree of the first electronic expansion valve to be equal to the sum of half of its full opening degree and the product of the condensation pressure correction parameter and its full opening degree; control the opening degree of the second electronic expansion valve to be equal to the difference between half of its full opening degree and the product of the condensation pressure correction parameter and its full opening degree.

3. The multi-connected air conditioner according to claim 2, wherein, It further includes an outlet water temperature sensor, which is electrically connected to the controller and is used to obtain the outlet water temperature of the water-fluorine heat exchanger and transmit it to the controller; The controller is further configured with a first hot water temperature correction value and a first hot water target condensation pressure, and its configuration further includes: The first hot water target condensation pressure is equal to the refrigerant saturation pressure corresponding to the sum of the outlet water temperature and the first hot water temperature correction value; In the hot water mode, the compressor control modes include a frequency increase control mode, a frequency decrease control mode, and a frequency holding operation mode; When the condensation pressure reaches the smaller value of the first hot water target condensation pressure and the third hot water target condensation pressure or below, the compressor operates in the frequency increase control mode; when the compressor is in the frequency increase control mode and the condensation pressure reaches the larger value of the first hot water target condensation pressure and the third hot water target condensation pressure or above, the compressor switches to the frequency holding operation mode; When the condensation pressure reaches the second hot water target condensation pressure or above, the compressor operates in the frequency decrease control mode; when the compressor is in the frequency decrease control mode and the condensation pressure reaches the larger value of the first hot water target condensation pressure and the third hot water target condensation pressure or below, the compressor switches to the frequency holding operation mode; When the compressor is in the frequency holding operation mode and the condensation pressure reaches the second hot water target condensation pressure or above, the compressor switches to the frequency decrease control mode; when the compressor is in the frequency holding operation mode and the condensation pressure reaches the smaller value of the first hot water target condensation pressure and the third hot water target condensation pressure or below, the compressor switches to the frequency increase control mode.

4. The multi-connected air conditioner according to claim 3, characterized in that, The configuration of the controller further includes: Compare the outlet water temperature with the hot water temperature; when the outlet water temperature reaches the hot water temperature or above, control the second electronic expansion valve to close; when the outlet water temperature reaches the hot water temperature or below, operate the hot water mode.

5. The multi-connected air conditioner according to claim 4, characterized in that, It further includes an outdoor fan, which is electrically connected to the controller and is controlled by the controller and is arranged corresponding to the outdoor heat exchanger; The controller is configured to control the speed of the outdoor fan to increase or decrease when operating the hot water mode so that the condensation pressure is controlled near the first hot water target condensation pressure.

6. The multi-connected air conditioner according to claim 5, wherein, It further includes: A temperature acquisition module, which is electrically connected to the controller and is used to acquire the temperature of the controller, denoted as the control temperature, and transmit it to the controller; The controller is further configured with a first condensation pressure correction value, a second condensation pressure correction value greater than the first condensation pressure correction value, a first control temperature threshold, and a second control temperature threshold greater than the first control temperature threshold; The configuration of the controller further includes: In the hot water mode, the controller receives the control temperature; And when it is determined that the control temperature reaches below the first control temperature threshold, correct the first hot water target condensation pressure by subtracting the first condensation pressure correction value; when the first hot water target condensation pressure is corrected by subtracting the first condensation pressure correction value and it is determined that the control temperature reaches the second control temperature threshold or above, switch to correcting the first hot water target condensation pressure by subtracting the second condensation pressure correction value; When it is determined that the control temperature reaches the second control temperature threshold or above, correct the first hot water target condensation pressure by subtracting the second condensation pressure correction value; when the first hot water target condensation pressure is corrected by subtracting the second condensation pressure correction value and it is determined that the control temperature reaches the first control temperature threshold or below, switch to correcting the first hot water target condensation pressure by subtracting the first condensation pressure correction value.

7. The multi-connected air conditioner according to claim 6, wherein The configuration of the controller further includes: A condensation pressure allowable threshold; When the first hot water target condensation pressure reaches the maximum value of the condensation pressure allowable threshold or above, the first hot water target condensation pressure is equal to the maximum value of the condensation pressure allowable threshold; When the first hot water target condensation pressure reaches the minimum value of the condensation pressure allowable threshold or below, the first hot water target condensation pressure is equal to the minimum value of the condensation pressure allowable threshold.

8. The multi-connected air conditioner according to claim 7, wherein The controller is further configured with a no-hot-water demand mode and a no-hot-water target condensation pressure; The controller is further configured to receive the condensation pressure in the no-hot-water demand mode and control the speed of the outdoor fan to increase or decrease so that the condensation pressure is controlled near the no-hot-water target condensation pressure; The configuration of the controller further includes: in the hot water mode, when the first hot water target condensation pressure does not exceed the no-hot-water target condensation pressure, the first hot water target condensation pressure is equal to the no-hot-water target condensation pressure.

9. The multi-connected air conditioner according to claim 8, wherein The first condensation pressure correction value is 0 Mpa; the second condensation pressure correction value is 0.3 MPa; the first control temperature threshold is 63 °C, and the second control temperature threshold is 65 °C; The allowable threshold value of the condensation pressure is between 2.4 MPa and 3.4 MPa; The first hot water temperature correction value and the second hot water temperature correction value both take the value of 6 °C.

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