A control method for heat recovery air conditioner

Abstract

The present invention relates to the technical field of air conditioning equipment, and in particular to a control method for a heat recovery air conditioner. The heat recovery air conditioner comprises a compressor, a four-way valve, an indoor heat exchanger, an outdoor heat exchanger throttling element, an outdoor heat exchanger, and a heat recovery water tank arranged in parallel with the outdoor heat exchanger; a heat exchanger for refrigerant heat exchange is provided in the heat recovery water tank, and a heat recovery throttling module is provided outside the heat recovery water tank; based on the influence of the water temperature in the heat recovery water tank on the heat exchange efficiency of the heat exchanger, the thermal expansion valve body automatically adjusts the amount of refrigerant passing through the heat exchanger according to the temperature change. Therefore, in the condensing circuit of the air conditioning system, only the throttling degree of the outdoor heat exchanger throttling element needs to be adjusted to achieve the purpose of adjusting the refrigerant circulation amount in the entire system. The control process is simple and reliable, and at the same time, heat can be recovered as much as possible to achieve the purpose of energy saving.

Description

Technical Field

[0001] The present invention relates to the technical field of air-conditioning equipment, and in particular to a control method for a heat recovery air-conditioning. Background Art

[0002] The existing air conditioning and hot water dual supply system controls the refrigerant circulation volume in the hot water circuit and the air conditioning condensing circuit respectively through two-way valve switching or using multiple electronic expansion valves in the hot water circuit and the air conditioning condensing circuit. The control process is complicated and multiple temperature sensors need to be arranged in the system in conjunction with multiple electronic expansion valves to achieve the purpose of controlling the refrigerant circulation volume in the hot water circuit and the air conditioning condensing circuit respectively.

[0003] A Chinese invention patent document, publication number CN109028650A, discloses a multi-split air conditioning and water heating system, comprising an indoor unit, a water heating module, and an outdoor unit. Multiple indoor units are provided, each including an indoor heat exchanger and an indoor electronic expansion valve; the water heating module includes a water tank heat exchanger; and the outdoor unit includes a compressor, an outdoor heat exchanger, and an outdoor electronic expansion valve. When hot water is needed, the compressor, water tank heat exchanger, indoor electronic expansion valve, indoor heat exchanger, and compressor are sequentially connected to form a first refrigerant circuit to produce hot water, while the indoor unit is cooling. Alternatively, the first refrigerant circuit, the compressor, water tank heat exchanger, outdoor electronic expansion valve, outdoor heat exchanger, and compressor are sequentially connected to form a second refrigerant circuit to jointly produce hot water, while the indoor unit is cooling. Alternatively, the second refrigerant circuit alone produces hot water, while the indoor unit is heating or shut down. This invention can recover indoor heat to produce hot water during cooling, and can also produce hot water through refrigerant circulation when the air conditioner is heating or shut down, saving energy.

[0004] In the above solution, multiple electronic expansion valves are provided, which makes the structure of the air-conditioning system quite complicated. In addition, during regulation, multiple electronic expansion valves need to be adjusted simultaneously, which increases inconvenience. Summary of the Invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a control method for a heat recovery air conditioner, which simplifies the structure of the heat recovery air conditioner system, reduces the control complexity of the refrigerant circulation system, and only needs to adjust one throttling element to achieve the purpose of controlling the refrigerant circulation amount of the system and improve the energy efficiency of the system.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0007] A control method for a heat recovery air conditioner, characterized in that the control method comprises:

[0008] S1: Determine whether the operation mode of the heat recovery air conditioner is the cooling mode. If the operation mode of the heat recovery air conditioner is the cooling mode, proceed to step S2; otherwise, proceed to step S17;

[0009] S2: Detect the water temperature Ts in the heat recovery water tank and the outdoor ambient temperature To, and then proceed to step S3;

[0010] S3: Obtain the difference between the outdoor ambient temperature To and the water temperature Ts in the heat recovery water tank, and compare the difference with the judgment threshold α (α can be set to a fixed value (such as 5°C) or a function of the outdoor ambient temperature To (α=f To )) compare, if the difference is greater than α, go to step S4, otherwise go to step S5;

[0011] S4: The initial throttling degree of the outdoor heat exchanger throttling element is set to a large value (e.g., the throttling degree is 0-100, when the throttling degree is 0, the throttling degree is the minimum; when the throttling degree is 100, the throttling degree is the maximum). For example, if the throttling degree is set to 60, then the process proceeds to step S7;

[0012] S5: Determine whether the water temperature Ts in the heat recovery water tank is greater than a preset threshold value β (e.g., 45°C). If yes, proceed to step S6; otherwise, proceed to step S4.

[0013] S6: The initial throttling degree of the outdoor heat exchanger throttling element is set to normal (e.g., the throttling degree is 0-100, when the throttling degree is 0, the throttling degree is minimum; when the throttling degree is 100, the throttling degree is maximum). If the throttling degree is set to 40, then go to step S7;

[0014] S7: The unit operates normally, and then proceeds to step S8;

[0015] S8: Detect the compressor exhaust temperature Td, and then proceed to step S9;

[0016] S9: Compare the compressor exhaust temperature Td with the initial compressor exhaust temperature Td0 when entering the cooling mode to determine whether it rises too fast. If so, proceed to step S15; otherwise, proceed to step S10.

[0017] S10: Determine whether the compressor exhaust temperature Td is too high. If yes, proceed to step S15; otherwise, proceed to step S11.

[0018] S11: Detect the outdoor heat exchanger temperature Tc, and then proceed to step S12;

[0019] S12: Calculate the temperature difference ΔT between the compressor exhaust temperature Td and the outdoor heat exchanger temperature Tc, and then proceed to step S13;

[0020] S13: Check whether the temperature difference △T is greater than γ (γ can be set to a fixed value (such as 40°C) or a function of the compressor exhaust temperature Td (γ=f Td )) Make a judgment, if the judgment result is yes, go to step S15, otherwise go to step S14;

[0021] S14: The throttling degree of the throttling element of the outdoor heat exchanger is increased, and then the process proceeds to step S16;

[0022] S15: The throttling degree of the outdoor heat exchanger throttling element is reduced, and then the process proceeds to step S16;

[0023] S16: Determine whether the unit operation mode is cooling. If the unit operation mode is cooling, proceed to step S7; otherwise, proceed to step S17;

[0024] S17: End the program.

[0025] Preferably, the heat recovery air conditioner comprises a compressor, a four-way valve, an indoor heat exchanger, a throttling element of an outdoor heat exchanger, an outdoor heat exchanger and a heat recovery water tank arranged in parallel with the outdoor heat exchanger; a heat exchanger for refrigerant heat exchange is provided in the heat recovery water tank, and a heat recovery throttling module is provided outside the heat recovery water tank;

[0026] The four-way valve includes a control valve port C, a control valve port D, a control valve port E, and a control valve port S. The control valve port C is connected to the compressor suction port through a first pipe, the control valve port D is connected to the inlet end of the indoor heat exchanger through a second pipe, the control valve port E is connected to the second port of the heat exchanger through a third pipe, and the control valve port S is connected to the compressor exhaust port through a fourth pipe;

[0027] The outlet end of the indoor heat exchanger is connected to the inlet end of the outdoor heat exchanger through a fifth pipe, and the outlet end of the outdoor heat exchanger is connected to the third pipe through a sixth pipe; a seventh pipe is connected to the fifth pipe and is connected to the first port of the heat exchanger;

[0028] The heat recovery throttling module includes: a thermal expansion valve temperature sensing package provided on the third pipe, and a thermal expansion valve body provided on the seventh pipe and connected to and communicating with the thermal expansion valve temperature sensing package; the thermal expansion valve temperature sensing package is capable of detecting the surface temperature of the third pipe; the connecting end of the third pipe and the sixth pipe is located between the thermal expansion valve temperature sensing package and the control valve port E;

[0029] When the heat recovery air conditioner is in cooling mode, the thermal expansion valve body can automatically adjust the throttling degree according to the surface temperature of the third pipe detected by the thermal expansion valve temperature sensor and the water temperature in the heat recovery water tank, thereby increasing / decreasing the amount of refrigerant passing through the heat exchanger;

[0030] The outdoor heat exchanger throttling element is arranged on the fifth pipe and is located between the connecting end of the fifth pipe and the seventh pipe and the inlet end of the outdoor heat exchanger, and is suitable for adjusting the refrigerant circulation amount in the air-conditioning system.

[0031] Preferably, an exhaust gas temperature sensor is provided on the fourth pipeline for detecting the compressor exhaust gas temperature Td in step S8.

[0032] Preferably, an outdoor temperature sensor is provided outside the outdoor heat exchanger for detecting the outdoor ambient temperature To in step S2.

[0033] Preferably, an outdoor heat exchanger temperature sensor is provided on the surface of the outdoor heat exchanger for detecting the outdoor heat exchanger temperature Tc in step S11.

[0034] Preferably, a water temperature sensor is provided in the heat recovery water tank for detecting the water temperature Ts of the heat recovery water tank in step S2.

[0035] Preferably, the heat recovery air conditioner further comprises a one-way valve, which is arranged on the seventh pipe and located between the thermal expansion valve body and the connecting ends of the fifth and seventh pipes, and is suitable for one-way flow from the thermal expansion valve body to the one-way valve.

[0036] Preferably, the heat recovery air conditioner includes an outdoor control mechanism and an indoor control mechanism that can respectively control the operating status of the outdoor heat exchanger and the indoor heat exchanger, and the indoor control mechanism can communicate with the outdoor control mechanism to determine whether the operating mode of the heat recovery air conditioner in steps S1 and S16 is the cooling mode.

[0037] Preferably, the throttling element of the outdoor heat exchanger is an electronic expansion valve, and the electronic expansion valve can adjust the throttling degree according to information transmitted by the outdoor control mechanism.

[0038] Preferably, when the heat recovery air conditioner is in cooling mode, the control valve port S is connected to the control valve port E, and the control valve port C is connected to the control valve port D. The main refrigerant passes through the compressor exhaust port, control valve port S, control valve port E, outdoor heat exchanger, outdoor heat exchanger throttling element, indoor heat exchanger, control valve port D, control valve port C in sequence, and finally flows back to the compressor suction port; the secondary refrigerant passes through the thermal expansion valve temperature sensor, heat recovery water tank / heat exchanger, thermal expansion valve body, one-way valve, indoor heat exchanger, control valve port D, control valve port C in sequence, and finally flows back to the compressor suction port.

[0039] The present invention adopts the above-mentioned technical solution by installing a thermal expansion valve body and a thermal expansion valve temperature sensor outside the heat recovery water tank. During the unit's cooling operation, the outdoor heat exchanger releases heat, and the thermal expansion valve temperature sensor senses the temperature rise on the third pipe. Based on the effect of the water temperature in the heat recovery water tank on the heat exchange efficiency of the heat exchanger, the thermal expansion valve body automatically adjusts the amount of refrigerant passing through the heat exchanger according to temperature changes. If the water temperature is high and the heat exchange efficiency is low, the throttling degree of the thermal expansion valve body is increased to reduce the amount of refrigerant passing through. If the water temperature is low and the heat exchange efficiency is high, the throttling degree of the thermal expansion valve body is decreased to increase the amount of refrigerant passing through, thereby improving the heat recovery effect. This control method is used in the hot water circuit.

[0040] Therefore, in the condensing circuit of the air-conditioning system, it is only necessary to adjust the throttling degree of the outdoor heat exchanger throttling element to achieve the purpose of adjusting the refrigerant circulation volume in the entire system. The control process is simple and reliable, and at the same time it can recover heat as much as possible to achieve the purpose of energy saving.

[0041] Generally speaking, when the outdoor ambient temperature is higher than the water temperature in the water tank to a certain extent, the heat exchange efficiency of the heat exchanger is higher than that of the outdoor heat exchanger. The initial throttling degree of the outdoor heat exchanger throttling element is increased to allow more refrigerant to flow into the heat exchanger, thereby improving the heat exchange efficiency of the entire system.

[0042] When the outdoor ambient temperature is higher than the water temperature in the water tank but does not reach a certain level and the water temperature in the water tank does not reach a certain value, the heat exchange efficiency of the heat exchanger is higher than that of the outdoor heat exchanger or the heat exchange efficiencies of the two are equivalent. The initial throttling degree of the throttling element of the outdoor heat exchanger is relatively increased to allow a large amount of refrigerant to flow to the outdoor heat exchanger, thereby improving the heat exchange efficiency of the entire system.

[0043] When the water temperature in the water tank is higher than a certain value, the heat exchange efficiency of the heat exchanger is significantly reduced. At this time, the initial throttling degree of the outdoor heat exchanger throttling element is reduced to allow more refrigerant to flow to the outdoor heat exchanger, thereby improving the heat exchange efficiency of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The present invention is a control logic diagram of a control method for a heat recovery air conditioner.

[0045] Figure 2 This is a system diagram of a heat recovery air conditioner.

[0046] Figure 3 The present invention is a flow chart of a heat recovery air conditioner in cooling mode. DETAILED DESCRIPTION

[0047] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0048] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 understood as limiting the present invention.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise explicitly specified.

[0050] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0051] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0052] like Figures 1 to 3A control method for a heat recovery air conditioner is shown, the control method comprising:

[0053] S1: Determine whether the operation mode of the heat recovery air conditioner is the cooling mode. If the operation mode of the heat recovery air conditioner is the cooling mode, proceed to step S2; otherwise, proceed to step S17;

[0054] S2: Detect the water temperature Ts in the heat recovery water tank 6 and the outdoor ambient temperature To, and then proceed to step S3;

[0055] S3: Obtain the difference between the outdoor ambient temperature To and the water temperature Ts in the heat recovery water tank 6, and compare the difference with the judgment threshold α (α can be set to a fixed value (such as 5°C) or a functional relationship with the outdoor ambient temperature To (α=f (To) )) compare, if the difference is greater than α, go to step S4, otherwise go to step S5;

[0056] S4: The initial throttling degree of the outdoor heat exchanger throttling element 4 is set to a large value (e.g., the throttling degree is 0-100, when the throttling degree is 0, the throttling degree is the minimum; when the throttling degree is 100, the throttling degree is the maximum). For example, if the throttling degree is set to 60, then the process proceeds to step S7;

[0057] S5: Determine whether the water temperature Ts in the heat recovery water tank 6 is greater than a preset threshold value β (such as 45°C). If the determination result is yes, proceed to step S6; otherwise, proceed to step S4;

[0058] S6: The initial throttling degree of the outdoor heat exchanger throttling element 4 is set to normal (e.g., the throttling degree is 0-100, when the throttling degree is 0, the throttling degree is minimum; when the throttling degree is 100, the throttling degree is maximum). If the throttling degree is set to 40, then go to step S7;

[0059] S7: The unit operates normally, and then proceeds to step S8;

[0060] S8: Detect the exhaust temperature Td of compressor 1, and then proceed to step S9;

[0061] S9: Compare the exhaust temperature Td of the compressor 1 with the initial exhaust temperature Td0 of the compressor 1 when entering the cooling mode to determine whether it rises too fast. If so, proceed to step S15; otherwise, proceed to step S10.

[0062] S10: Determine whether the exhaust gas temperature Td of compressor 1 is too high. If yes, proceed to step S15; otherwise, proceed to step S11.

[0063] S11: Detect the temperature Tc of the outdoor heat exchanger 5, and then proceed to step S12;

[0064] S12: Calculate the temperature difference ΔT between the exhaust temperature Td of the compressor 1 and the temperature Tc of the outdoor heat exchanger 5, and then proceed to step S13;

[0065] S13: Check whether the temperature difference ΔT is greater than γ (γ can be set to a fixed value (such as 40°C) or a function of the exhaust temperature Td of the compressor (1) (γ = f (Td) )) Make a judgment, if the judgment result is yes, go to step S15, otherwise go to step S14;

[0066] S14: The throttling degree of the outdoor heat exchanger throttling element 4 is increased, and then the process proceeds to step S16;

[0067] S15: The throttling degree of the outdoor heat exchanger throttling element 4 is reduced, and then the process proceeds to step S16;

[0068] S16: Determine whether the unit operation mode is cooling. If the unit operation mode is cooling, proceed to step S7; otherwise, proceed to step S17;

[0069] S17: End the program.

[0070] Furthermore, the heat recovery air conditioner includes a compressor 1, a four-way valve 2, an indoor heat exchanger 3, an outdoor heat exchanger throttling element 4, an outdoor heat exchanger 5, and a heat recovery water tank 6 arranged in parallel with the outdoor heat exchanger 5; a heat exchanger 7 for refrigerant heat exchange is provided in the heat recovery water tank 6, and a heat recovery throttling module is provided outside the heat recovery water tank 6;

[0071] The four-way valve 2 includes a control valve port C, a control valve port D, a control valve port E, and a control valve port S. The control valve port C is connected to the compressor suction port 9 through a first pipe 8, the control valve port D is connected to the inlet end 11 of the indoor heat exchanger through a second pipe 10, the control valve port E is connected to the second port of the heat exchanger 7 through a third pipe 12, and the control valve port S is connected to the compressor exhaust port 15 through a fourth pipe 14;

[0072] The outlet end 16 of the indoor heat exchanger is connected to the inlet end 18 of the outdoor heat exchanger through a fifth pipe 17, and the outlet end 19 of the outdoor heat exchanger is connected to the third pipe 12 through a sixth pipe 20; a seventh pipe 21 is connected to the fifth pipe 17 and is connected to the first port 22 of the heat exchanger;

[0073] The heat recovery throttling module includes: a thermal expansion valve temperature sensing package 23 provided on the third pipe 12, and a thermal expansion valve body 24 provided on the seventh pipe 21 and connected to and communicating with the thermal expansion valve temperature sensing package 23; the thermal expansion valve temperature sensing package 23 is capable of detecting the surface temperature of the third pipe 12; the connection end between the third pipe 12 and the sixth pipe 20 is located between the thermal expansion valve temperature sensing package 23 and the control valve port E;

[0074] When the heat recovery air conditioner is in cooling mode, the thermal expansion valve body 24 can automatically adjust the throttling degree according to the surface temperature of the third pipe 12 detected by the thermal expansion valve temperature sensing package 23 and the water temperature in the heat recovery water tank 6, thereby increasing / decreasing the amount of refrigerant passing through the heat exchanger 7;

[0075] The outdoor heat exchanger throttling element 4 is arranged on the fifth pipe 17 and between the connecting end of the fifth pipe 17 and the seventh pipe 21 and the inlet end 18 of the outdoor heat exchanger, and is suitable for adjusting the refrigerant circulation amount in the air-conditioning system.

[0076] Furthermore, an exhaust gas temperature sensor 25 is provided on the fourth pipe 14 for detecting the exhaust gas temperature Td of the compressor 1 in step S8.

[0077] Furthermore, the outdoor heat exchanger 5 is provided with an outdoor temperature sensor 26 for detecting the outdoor ambient temperature To in step S2.

[0078] Furthermore, an outdoor heat exchanger temperature sensor 27 is provided on the surface of the outdoor heat exchanger 5 for detecting the temperature Tc of the outdoor heat exchanger 5 in step S11.

[0079] Furthermore, a water temperature sensor 28 is provided in the heat recovery water tank 6 for detecting the water temperature Ts of the heat recovery water tank 6 in step S2.

[0080] Furthermore, the heat recovery air conditioner also includes a one-way valve 29, which is arranged on the seventh pipe 21 and is located between the thermal expansion valve body 24 and the connecting end of the fifth pipe 17 and the seventh pipe 21, and is suitable for one-way flow from the thermal expansion valve body 24 to the one-way valve 29.

[0081] Furthermore, the heat recovery air conditioner includes an outdoor control mechanism 30 and an indoor control mechanism 31, which can respectively control the operating status of the outdoor heat exchanger 5 and the indoor heat exchanger 3. The indoor control mechanism 31 can communicate with the outdoor control mechanism 30 to determine whether the operating mode of the heat recovery air conditioner in steps S1 and S16 is the cooling mode.

[0082] Furthermore, the outdoor heat exchanger throttling element 4 is an electronic expansion valve, which can adjust the throttling degree according to the information transmitted by the outdoor control mechanism 30.

[0083] Furthermore, when the heat recovery air conditioner is in cooling mode, the control valve port S is connected to the control valve port E, and the control valve port C is connected to the control valve port D. The main refrigerant passes through the compressor exhaust port 15, the control valve port S, the control valve port E, the outdoor heat exchanger 5, the outdoor heat exchanger throttling element 4, the indoor heat exchanger 3, the control valve port D, the control valve port C in sequence, and finally flows back to the compressor intake port 9; the secondary refrigerant passes through the thermal expansion valve temperature sensor 23, the heat recovery water tank 6 / heat exchanger 7, the thermal expansion valve body 24, the one-way valve 29, the indoor heat exchanger 3, the control valve port D, the control valve port C in sequence, and finally flows back to the compressor intake port 9.

[0084] In this specific embodiment, in view of the complexity of the existing air conditioning and hot water dual-generation system, multiple electronic expansion valves need to be set to control the hot water circuit and the air conditioning condensing circuit respectively. In the above scheme, by streamlining the system structure of the heat recovery air conditioner, the refrigerant amount of the hot water circuit is automatically adjusted through the thermal expansion valve body 24 and the thermal expansion valve temperature sensing package 23, and in the air conditioning condensing circuit, only one outdoor heat exchanger throttling element 4 is required to achieve precise control of the refrigerant amount in the air conditioning condensing circuit.

[0085] Generally speaking, when the outdoor ambient temperature is higher than the water temperature in the water tank to a certain extent, the heat exchange efficiency of the heat exchanger 7 is higher than that of the outdoor heat exchanger 5. The initial throttling degree of the outdoor heat exchanger throttling element 4 is increased to allow a large amount of refrigerant to flow to the heat exchanger 7, thereby improving the heat exchange efficiency of the entire system and enhancing the heat recovery effect of the heat recovery water tank 6.

[0086] When the outdoor ambient temperature is higher than the water temperature in the water tank but does not reach a certain level and the water temperature in the water tank does not reach a certain value, the heat exchange efficiency of the heat exchanger is higher than that of the outdoor heat exchanger or the heat exchange efficiencies of the two are equivalent. The initial throttling degree of the throttling element of the outdoor heat exchanger is relatively increased to allow a large amount of refrigerant to flow to the outdoor heat exchanger, thereby improving the heat exchange efficiency of the entire system.

[0087] When the water temperature in the water tank is higher than a certain value, the heat exchange efficiency of the heat exchanger is significantly reduced. At this time, the initial throttling degree of the outdoor heat exchanger throttling element is reduced to allow more refrigerant to flow to the outdoor heat exchanger, thereby improving the heat exchange efficiency of the entire system.

[0088] It should be noted here that 100 is the outlet pipe of the heat recovery water tank, and 101 is the inlet pipe of the heat recovery water tank.

[0089] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0090] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A control method for a heat recovery air conditioner, characterized in that: The heat recovery air conditioner comprises a compressor (1), a four-way valve (2), an indoor heat exchanger (3), an outdoor heat exchanger throttling element (4), an outdoor heat exchanger (5), and a heat recovery water tank (6) arranged in parallel with the outdoor heat exchanger (5); a heat exchanger (7) for refrigerant heat exchange is arranged in the heat recovery water tank (6), and a heat recovery throttling module is arranged outside the heat recovery water tank (6); The four-way valve (2) includes a control valve port C, a control valve port D, a control valve port E, and a control valve port S. The control valve port C is connected to the compressor suction port (9) through a first pipe (8), the control valve port D is connected to the inlet end (11) of the indoor heat exchanger through a second pipe (10), the control valve port E is connected to the second port of the heat exchanger (7) through a third pipe (12), and the control valve port S is connected to the compressor discharge port (15) through a fourth pipe (14); The outlet end (16) of the indoor heat exchanger is connected to the inlet end (18) of the outdoor heat exchanger via a fifth pipe (17), and the outlet end (19) of the outdoor heat exchanger is connected to the third pipe (12) via a sixth pipe (20); a seventh pipe (21) is connected to the fifth pipe (17) and is connected to the first port (22) of the heat exchanger; The heat recovery throttling module comprises: a thermal expansion valve temperature sensing package (23) arranged on the third pipe (12), and a thermal expansion valve body (24) arranged on the seventh pipe (21) and connected to and communicating with the thermal expansion valve temperature sensing package (23); the thermal expansion valve temperature sensing package (23) is capable of detecting the surface temperature of the third pipe (12); the connection end of the third pipe (12) and the sixth pipe (20) is located between the thermal expansion valve temperature sensing package (23) and the control valve port E; When the heat recovery air conditioner is in cooling mode, the thermal expansion valve body (24) can automatically adjust the throttling degree according to the surface temperature of the third pipe (12) detected by the thermal expansion valve temperature sensor (23) and the water temperature in the heat recovery water tank (6), thereby increasing / decreasing the amount of refrigerant passing through the heat exchanger (7); The outdoor heat exchanger throttling element (4) is arranged on the fifth pipe (17) and between the connection end of the fifth pipe (17) and the seventh pipe (21) and the inlet end (18) of the outdoor heat exchanger, and is suitable for adjusting the refrigerant circulation amount in the air-conditioning system; The control method includes: S1: Determine whether the operation mode of the heat recovery air conditioner is the cooling mode. If the operation mode of the heat recovery air conditioner is the cooling mode, proceed to step S2; otherwise, proceed to step S17; S2: Detect the water temperature Ts in the heat recovery water tank (6) and the outdoor ambient temperature To, and then proceed to step S3; S3: Obtain the difference between the outdoor ambient temperature To and the water temperature Ts in the heat recovery water tank (6), and compare the difference with the judgment threshold α, where α can be set to a fixed value or a functional relationship with the outdoor ambient temperature To α = f （To） ; If the difference is greater than α, go to step S4, otherwise go to step S5; S4: Set the initial throttling degree of the outdoor heat exchanger throttling element (4) to 60, and then proceed to step S7; S5: Determine whether the water temperature Ts in the heat recovery water tank (6) is greater than a preset threshold value β. If the determination result is yes, proceed to step S6; otherwise, proceed to step S4; S6: Set the initial throttling degree of the outdoor heat exchanger throttling element (4) to 40, and then proceed to step S7; S7: The unit operates normally, and then enters step S8; S8: Detect the exhaust temperature Td of the compressor (1), and then proceed to step S9; S9: Compare the exhaust temperature Td of the compressor (1) with the initial exhaust temperature Td0 of the compressor (1) when entering the cooling mode to determine whether it rises too fast. If the determination result is yes, proceed to step S15; otherwise, proceed to step S10; S10: Determine whether the exhaust temperature Td of the compressor (1) is too high. If the determination result is yes, proceed to step S15; otherwise, proceed to step S11; S11: Detect the temperature Tc of the outdoor heat exchanger (5), and then proceed to step S12; S12: Calculate the temperature difference ΔT between the exhaust temperature Td of the compressor (1) and the temperature Tc of the outdoor heat exchanger (5), and then proceed to step S13; S13: Determine whether the temperature difference △T is greater than γ, where γ can be set to a fixed value or a functional relationship with the exhaust temperature Td of the compressor (1) γ = f （Td） ; If the judgment result is yes, go to step S15, otherwise go to step S14; S14: The throttling degree of the outdoor heat exchanger throttling element (4) is increased, and then the process proceeds to step S16; S15: The throttling degree of the outdoor heat exchanger throttling element (4) is reduced, and then the process proceeds to step S16; S16: Determine whether the unit operation mode is cooling. If the unit operation mode is cooling, proceed to step S7; otherwise, proceed to step S17; S17: End the program.

2. The control method of a heat recovery air conditioner according to claim 1, characterized in that: An exhaust gas temperature sensor (25) is provided on the fourth pipe (14) for detecting the exhaust gas temperature Td of the compressor (1) in step S8.

3. The control method of a heat recovery air conditioner according to claim 1, characterized in that: The outdoor heat exchanger (5) is provided with an outdoor temperature sensor (26) for detecting the outdoor ambient temperature To in step S2.

4. The control method of a heat recovery air conditioner according to claim 1, characterized in that: An outdoor heat exchanger temperature sensor (27) is provided on the surface of the outdoor heat exchanger (5) for detecting the temperature Tc of the outdoor heat exchanger (5) in step S11.

5. The control method of a heat recovery air conditioner according to claim 1, characterized in that: The heat recovery water tank (6) is provided with a water temperature sensor (28) for detecting the water temperature Ts of the heat recovery water tank (6) in step S2.

6. The control method of a heat recovery air conditioner according to claim 1, characterized in that: The heat recovery air conditioner further comprises a one-way valve (29), which is arranged on the seventh pipe (21) and is located between the thermal expansion valve body (24) and the connection end between the fifth pipe (17) and the seventh pipe (21), and is suitable for one-way flow from the thermal expansion valve body (24) to the one-way valve (29).

7. The control method of a heat recovery air conditioner according to claim 6, characterized in that: The heat recovery air conditioner includes an outdoor control mechanism (30) and an indoor control mechanism (31) capable of controlling the operating states of the outdoor heat exchanger (5) and the indoor heat exchanger (3), respectively. The indoor control mechanism (31) and the outdoor control mechanism (30) can communicate to determine whether the operating mode of the heat recovery air conditioner is the cooling mode in steps S1 and S16.

8. The control method of a heat recovery air conditioner according to claim 7, characterized in that: The outdoor heat exchanger throttling element (4) is an electronic expansion valve, and the electronic expansion valve can adjust the throttling degree according to information transmitted by the outdoor control mechanism (30).

9. The control method of a heat recovery air conditioner according to claim 1, characterized in that: When the heat recovery air conditioner is in cooling mode, the control valve port S is connected to the control valve port E, and the control valve port C is connected to the control valve port D. The main refrigerant passes through the compressor exhaust port (15), the control valve port S, the control valve port E, the outdoor heat exchanger (5), the outdoor heat exchanger throttling element (4), the indoor heat exchanger (3), the control valve port D, the control valve port C, and finally flows back to the compressor intake port (9); the secondary refrigerant passes through the thermal expansion valve temperature sensor (23), the heat recovery water tank (6) / heat exchanger (7), the thermal expansion valve body (24), the one-way valve (29), the indoor heat exchanger (3), the control valve port D, the control valve port C, and finally flows back to the compressor intake port (9).

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