Outdoor unit condenser, outdoor unit and variable frequency air conditioner

Abstract

The present invention relates to the technical field of air conditioning, and particularly relates to an outdoor unit condenser, an outdoor unit and a variable frequency air conditioner. The present invention aims to solve the problem of low heating efficiency existing in existing air conditioners. For this purpose, the outdoor unit condenser of the present invention includes a heat exchange pipe section, a subcooling pipe section, a first regulating valve, a subcooling connecting pipe and a plurality of subcooling valves. The first end of the subcooling pipe section can be connected to the indoor unit evaporator through a second regulating valve. The first end and the second end of the subcooling pipe section are separated into n subcooling intervals by a plurality of subcooling valves. Each of the plurality of subcooling intervals is connected to the first end of the first regulating valve through a subcooling connecting pipe, and the second end of the first regulating valve is connected to the heat exchange pipe section. The above setting method can improve the heating energy efficiency, inhibit frosting and effectively defrost.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and particularly to an outdoor unit condenser, an outdoor unit and a variable frequency air conditioner. Background Art

[0002] Compared with fixed-frequency air conditioners, variable frequency air conditioners can automatically adjust the frequency of the compressor according to the indoor temperature conditions to ensure that the indoor environment is always in a relatively stable temperature range, so they are increasingly favored by the public.

[0003] Traditional variable frequency air conditioners only evaluate the refrigeration energy efficiency and power, and use the refrigeration energy efficiency as the evaluation standard for the energy efficiency level, without requirements for the heating power and capacity. Therefore, when developing variable frequency air conditioners, R & D personnel generally design based on the best refrigeration energy efficiency. However, with the introduction and implementation of the new national energy efficiency standard, the refrigeration, heating power and energy efficiency of variable frequency air conditioners are all included in the assessment scope, and the heating energy efficiency has a great impact on the overall energy efficiency of the air conditioner. Therefore, reducing the heating power of variable frequency air conditioners and improving their heating energy efficiency have become one of the most critical tasks in the industry.

[0004] In addition, during the low-temperature heating process, especially when operating in a low-temperature and high-humidity environment, the frosting speed of the outdoor unit is very fast. As the frost layer thickens, the heating effect deteriorates seriously. Therefore, how to effectively defrost while improving the heating energy efficiency is also one of the problems faced by this field.

[0005] Correspondingly, the present field needs a new outdoor unit condenser, an outdoor unit and a variable frequency air conditioner to solve the above problems. Summary of the Invention

[0006] In order to solve the above problems in the prior art, that is, to solve the problem of low heating efficiency existing in existing air conditioners, the present invention provides an outdoor unit condenser, which includes a heat exchange pipe section, a subcooling pipe section, a first regulating valve, a subcooling connecting pipe and a plurality of subcooling valves. The first end of the subcooling pipe section can be connected to the indoor unit evaporator through a second regulating valve. The first end and the second end of the subcooling pipe section are separated into n subcooling intervals by the plurality of subcooling valves. A plurality of the subcooling intervals are respectively connected to the first end of the first regulating valve through a subcooling connecting pipe. The second end of the first regulating valve is connected to the heat exchange pipe section. The plurality of subcooling valves are configured to be able to adjust the effective length of the subcooling pipe section by controlling the opening and closing of each subcooling valve. The first regulating valve is configured to open a set opening when the heat exchange medium flows from the indoor unit evaporator to the outdoor unit condenser.

[0007] In the preferred technical solution of the above outdoor unit condenser, the second end of the subcooling pipe section is connected to the heat exchange pipe section. The outdoor unit condenser further includes a confluence connection pipe and a plurality of confluence valves. Each of the plurality of subcooling intervals is connected to the second end of the first regulating valve through a confluence connection pipe, and each confluence connection pipe is provided with a confluence valve.

[0008] In the preferred technical solution of the above outdoor unit condenser, the subcooling connection pipes are provided on the 1st to the (n - 1)th subcooling intervals starting from the first end of the subcooling pipe section, and the confluence connection pipes are provided on the 2nd to the nth subcooling intervals starting from the first end of the subcooling pipe section.

[0009] In the preferred technical solution of the above outdoor unit condenser, the outdoor unit condenser further includes a plurality of on-off valves, and each of the plurality of subcooling connection pipes is provided with an on-off valve.

[0010] In the preferred technical solution of the above outdoor unit condenser, the on-off valve is a one-way valve, and the one-way valve is provided on the 2nd to the (n - 1)th subcooling connection pipes starting from the first end of the subcooling pipe section; or the on-off valve is an electromagnetic valve, and the electromagnetic valve is provided on all the subcooling connection pipes.

[0011] In the preferred technical solution of the above outdoor unit condenser, the outdoor unit condenser further includes a defrosting temperature detection element arranged on the heat exchange pipe section. The defrosting temperature detection element can be connected to a controller so that the controller adjusts the opening and closing of the plurality of subcooling valves based on the temperature collected by the defrosting temperature detection element.

[0012] In the preferred technical solution of the above outdoor unit condenser, the outdoor unit condenser further includes a subcooling temperature detection element arranged on the subcooling pipe section. The subcooling temperature detection element can be connected to a controller so that the controller adjusts the opening degree of the first regulating valve based on the temperature collected by the subcooling temperature detection element.

[0013] In the preferred technical solution of the above outdoor unit condenser, the subcooling pipe section is arranged on the windward side of the outdoor unit condenser; and / or the subcooling pipe section is arranged below the heat exchange pipe section.

[0014] The present invention also provides an outdoor unit, which includes the outdoor unit condenser according to any one of the above preferred technical solutions.

[0015] The present invention also provides a variable frequency air conditioner, which includes the outdoor unit according to the above preferred technical solution.

[0016] Those skilled in the art can understand that, in the preferred technical scheme of the present invention, the outdoor unit condenser includes a heat exchange pipe section, a subcooling pipe section, a first regulating valve, a subcooling connecting pipe and several subcooling valves, the first end of the subcooling pipe section can be connected to the indoor unit evaporator through the second regulating valve, the first end and the second end of the subcooling pipe section are divided into n subcooling intervals by several subcooling valves, several of the subcooling intervals are each connected to the first end of the first regulating valve through a subcooling connecting pipe, the second end of the first regulating valve is connected to the heat exchange pipe section, the several subcooling valves are configured to be able to adjust the effective length of the subcooling pipe section by controlling the opening and closing of each of the subcooling valves, and the first regulating valve is configured to open a set opening when the heat exchange medium flows from the indoor unit evaporator to the outdoor unit condenser.

[0017] By setting a first regulating valve between the heat exchange pipe section and the subcooling pipe section of the outdoor unit condenser, the air conditioner can achieve precise control of the subcooling degree through the change of the opening of the first regulating valve when heating, so that the subcooling pipe section of the outdoor unit condenser acts as an extension and supplement of the indoor unit evaporator, which increases the heat exchange area of the indoor unit evaporator in disguised form, lengthens the subcooling section on the high-pressure side, and further reduces the temperature of the heat exchange medium, reduces the saturation pressure on the high-pressure side, thereby reducing the power of the compressor and greatly reducing the heating energy consumption. After repeated experiments, observations, analyses and comparisons by the inventor, the heating energy efficiency of the air conditioner using the heat exchanger of the present application can be accurately controlled and basically reaches the refrigeration energy efficiency level when the above-mentioned setting method is adopted.

[0018] By using a plurality of subcooling valves to divide the subcooling pipe section into n subcooling intervals, and the plurality of subcooling intervals are connected to the first end of the first regulating valve through a subcooling connecting pipe, it is further possible to adjust the opening and closing of the plurality of subcooling valves to adjust the effective length of the subcooling pipe section during heating, thereby suppressing frost or performing defrost operations on the outdoor unit condenser through the change in the effective length of the subcooling pipe section, thereby improving the heating efficiency.

[0019] Furthermore, by arranging a defrost temperature detection element on the heat exchange pipe section, the controller can timely and reasonably adjust the opening and closing of several subcooling valves based on the temperature of the heat exchange pipe section, thereby realizing the adjustment of the effective length of the subcooling pipe section, ensuring the heat exchange effect of the superheating pipe section, avoiding frost on the heat exchange pipeline, and improving the heating effect.

[0020] Furthermore, by arranging a temperature detection element on the supercooling pipe section, the opening of the first regulating valve can be adjusted based on the temperature of the supercooling pipe section, so that the first regulating valve can be accurately adjusted during heating, further reducing the power of the compressor and improving the heating energy efficiency.

[0021] Furthermore, the first end of the subcooled pipe section can be connected to the indoor unit evaporator through the second regulating valve. When the outdoor unit condenser is applied to an air conditioner, during the heating process of the air conditioner, the heating target exhaust temperature and subcooling degree of the system can be accurately adjusted by jointly regulating the opening degrees of the first regulating valve and the second regulating valve, thereby reducing the heating power and improving the heating energy efficiency.

[0022] Furthermore, arranging the subcooled pipe section on the windward side and below the heat exchange pipe section can increase the heat exchange capacity of the heat exchange pipe section on the leeward side, further reduce the compressor power, inhibit frosting or improve the defrosting effect. This is because, usually, the temperature of the heat exchange medium in the subcooled section of the pipe after one throttling is still higher than the ambient temperature. Before the second throttling, through the heat exchange between the subcooled pipe section and the air flow, the heat released by the subcooled pipe section is blown onto the heat exchange pipe section on the leeward side by the air flow for heat exchange. The heat exchange medium in the heat exchange pipe section on the leeward side has reached the low-temperature and low-pressure state after the second throttling, and the initial heat exchange pipe is more likely to frost due to sufficient heat exchange. In this way, it can not only reduce the high-pressure side pressure and thus reduce the compressor power, but also ensure the heat exchange effect of the heat exchange pipe section, achieving the effect of inhibiting frosting when there is no frost and effectively defrosting when there is frost, and greatly improving the overall energy efficiency. Brief Description of the Drawings

[0023] The outdoor unit condenser, outdoor unit and variable-frequency air conditioner of the present invention will be described below with reference to the drawings. In the drawings:

[0024] Figure 1 is a system schematic diagram of the variable-frequency air conditioner in the first embodiment of the present invention;

[0025] Figure 2 is a system schematic diagram of the variable-frequency air conditioner in the second embodiment of the present invention;

[0026] Figure 3 is a partial schematic diagram of the variable-frequency air conditioner in the third embodiment of the present invention;

[0027] Figure 4 is a partial schematic diagram of the variable-frequency air conditioner in the fourth embodiment of the present invention;

[0028] Figure 5 is a flowchart of the control method of the air conditioner of the present invention;

[0029] Figure 6 is a logic diagram of the control method of the air conditioner of the present invention.

[0030] List of Reference Numerals

[0031] 1. Variable-frequency compressor; 2. Four-way valve; 3. Indoor evaporator; 4. Indoor fan; 5. Outdoor condenser; 51. Heat exchange tube section; 52. Subcooling tube section; 53. First regulating valve; 54. Subcooling connecting pipe; 55a, 55b, 55c. Subcooling valves; 56. Confluence connecting pipe; 57a, 57b, 57c. Confluence valves; 58a, 58b, 58c. On-off valves; 6. Outdoor fan; 7. Second regulating valve. Detailed implementation manners

[0032] The preferred implementation manners of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention. For example, although the outdoor condenser in the accompanying drawings is described in combination with a double-row condenser, the specific form of the outdoor condenser is not fixed, and those skilled in the art can adjust it according to needs to adapt to specific application scenarios. For example, the present invention can also be applied to a triple-row condenser or a single-row condenser, etc.

[0033] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0035] Example 1

[0036] First, refer to Figure 1 , to describe the variable-frequency air conditioner of the present invention. Among them, Figure 1 is the system schematic diagram of the variable-frequency air conditioner in the first implementation manner of the present invention.

[0037] As Figure 1As shown, to solve the problem of low heating efficiency of existing variable-frequency air conditioners, the present application provides a variable-frequency air conditioner, which includes an indoor unit, an outdoor unit, and a pipeline connecting the indoor unit and the outdoor unit. Among them, the outdoor unit includes a variable-frequency compressor 1, a four-way valve 2, an outdoor condenser 5, an outdoor fan 6, and a second regulating valve 7, and the indoor unit includes an indoor evaporator 3 and an indoor fan 4. Among them, the outdoor condenser 5 includes a heat exchange pipe section 51, a subcooling pipe section 52, a first regulating valve 53, a subcooling connecting pipe 54, and a plurality of subcooling valves (55a, 55b). Both the heat exchange pipe section 51 and the subcooling pipe section 52 are formed by connecting U-shaped pipes end to end. The first end ( Figure 1 the lower end in) of the subcooling pipe section 52 is connected to the indoor evaporator 3 through the second regulating valve 7. A plurality of subcooling valves (55a, 55b) are arranged on the subcooling pipe section 52 and divide the first end and the second end ( Figure 1 the upper end in) of the subcooling pipe section 52 into n subcooling intervals. A plurality of the subcooling intervals are respectively connected to the first end ( Figure 1 the right end in) of the first regulating valve 53 through a subcooling connecting pipe 54, and the second end ( Figure 1 the left end in) of the first regulating valve 53 is connected to the heat exchange pipe section 51. Among them, a plurality of subcooling valves (55a, 55b) are arranged to be able to adjust the effective length of the subcooling pipe section 52 by controlling the opening and closing of each of the subcooling valves (55a, 55b). The first regulating valve 53 is arranged to be fully open when the heat exchange medium (such as refrigerant, etc.) flows from the outdoor condenser 5 to the indoor evaporator 3, and to open a set opening when the heat exchange medium flows from the indoor evaporator 3 to the outdoor condenser 5.

[0038] It should be explained that in the present application, the effective length refers to the length of the part of the subcooling pipe section 52 that plays a subcooling role. This length can be controlled by controlling the opening and closing of the subcooling valves (55a, 55b), and the longest effective length is the full length of the subcooling pipe section 52. The set opening refers to any opening between fully closed and fully open, and the specific size of the opening can be controlled based on parameters, such as being controlled based on parameters such as the outdoor ambient temperature, the temperature of the subcooling pipe section 52, etc.

[0039] Refer to Figure 1Taking the heat exchange medium as refrigerant as an example, when the variable frequency air conditioner operates in the cooling mode, the first regulating valve 53 is fully opened, and the second regulating valve 7 is opened to a set opening according to the conventional control method. The refrigerant is discharged from the exhaust port of the variable frequency compressor 1 and enters the outdoor unit condenser 5 and flows through the heat exchange pipe section 51, the first regulating valve 53, the subcooling connecting pipe 54 and the subcooling pipe section 52 in sequence to condense and exchange heat with the outdoor air. The refrigerant after heat exchange enters the indoor unit evaporator 3 after throttling by the second regulating valve 7 to evaporate and exchange heat with the indoor air. The refrigerant after heat exchange returns to the variable frequency compressor 1 from the air intake port of the variable frequency compressor 1, completing a refrigeration cycle. When the variable frequency air conditioner operates in heating mode, the first regulating valve 53 and the second regulating valve 7 are respectively opened to a set opening, and the subcooling valve (55a, 55b) is opened and closed according to the set control method to adjust the effective length of the subcooling pipe section 52. After being discharged from the exhaust port of the variable frequency compressor 1, the refrigerant first enters the indoor unit evaporator 3 to condense and exchange heat with the indoor air. After the heat exchange, the refrigerant enters the subcooling pipe section 52 after the first throttling and cooling by the second regulating valve 7. The temperature of the refrigerant entering the subcooling pipe section 52 is still relatively high. At this time, the refrigerant in the effective length part of the subcooling pipe section 52 is further condensed and exchanged heat with the outdoor air, and then flows into the first regulating valve 53 after passing through the subcooling connecting pipe 54, and enters the heat exchange pipe section 51 under the secondary throttling of the first regulating valve 53 to evaporate and exchange heat with the outdoor air. The refrigerant after heat exchange returns to the variable frequency compressor 1 from the air intake port of the variable frequency compressor 1 to complete a heating cycle.

[0040] From the above description, it can be seen that by setting the first regulating valve 53 between the heat exchange pipe section 51 and the subcooling pipe section 52 of the outdoor unit condenser 5, when the variable frequency air conditioner is cooling, by fully opening the first regulating valve 53, the first regulating valve 53 can be prevented from affecting the cooling energy efficiency, and by adjusting the opening of the second regulating valve 7, the normal frequency adjustment of the air conditioner can be achieved; when heating, by controlling the opening change of the first regulating valve 53, the supercooling degree can be accurately controlled, so that the subcooling pipe section 52 of the outdoor unit condenser 5 acts as an extension and supplement of the indoor unit evaporator 3, which increases the heat exchange area of the indoor unit evaporator 3 in disguised form, lengthens the subcooling section on the high-pressure side, and further reduces the temperature of the heat exchange medium, reduces the saturation pressure on the high-pressure side, thereby reducing the power of the compressor and greatly reducing the heating energy consumption. After repeated experiments, observations, analysis and comparisons by the inventor, the heating energy efficiency of the air conditioner using the heat exchanger of the present application can be accurately controlled and basically reaches the level of cooling energy efficiency when the above-mentioned setting is adopted.

[0041] Furthermore, by using a plurality of subcooling valves (55a, 55b), the subcooling pipe section 52 is divided into n subcooling intervals, and the plurality of subcooling intervals are connected to the first end of the first regulating valve 53 through subcooling connecting pipes 54. Further, during heating, the effective length of the subcooling pipe section 52 can be adjusted by adjusting the opening and closing of the plurality of subcooling valves (55a, 55b), so as to suppress frosting or defrost the outdoor unit condenser 5 by changing the effective length of the subcooling pipe section 52, thereby improving the heating efficiency.

[0042] The following further refers to Figure 1 and, in combination with two subcooling valves (55a, 55b) provided on the subcooling pipe section 52, a first embodiment of the variable-frequency air conditioner of the present application will be described in detail.

[0043] As Figure 1 shown, in a more preferred embodiment, the two subcooling valves (55a, 55b) divide the subcooling pipe section 52 into three subcooling intervals, and each of the three subcooling intervals is connected to the first end of the first regulating valve 53 through a subcooling connecting pipe 54. Among them, an on-off valve (58a, 58b, 58c) is further provided on each subcooling connecting pipe 54. By controlling the opening and closing of the subcooling valves (55a, 55b) and the on-off valves (58a, 58b, 58c), the effective length of the subcooling pipe section 52 can be controlled. For example, when the subcooling valve 55a is closed, the on-off valve 58a is opened, and 58b and 58c are closed, the effective length of the subcooling pipe section 52 is the length of the first subcooling interval close to the first end ( Figure 1 the lower end in) of the subcooling pipe section 52; when the subcooling valve 55a is opened, 55b is closed, the on-off valve 58b is opened, and 58a and 58c are closed, the effective length of the subcooling pipe section 52 is the sum of the lengths of the first subcooling interval and the second subcooling interval starting from the first end of the subcooling pipe section 52, and so on. Among them, the subcooling valves (55a, 55b) and the on-off valves (58a, 58b, 58c) can be electrically controlled valves such as solenoid valves and electronic expansion valves.

[0044] Through the arrangement of the subcooling valves (55a, 55b) and the on-off valves (58a, 58b, 58c), during heating, the effective length of the subcooling pipe section 52 can be adjusted by adjusting the opening and closing of the subcooling valves (55a, 55b) and the on-off valves (58a, 58b, 58c), so as to suppress frosting or defrost the outdoor unit condenser 5 by changing the effective length of the subcooling pipe section 52, thereby improving the heating efficiency.

[0045] Continuing to refer to Figure 1 and, in a more preferred embodiment, the outdoor unit condenser 5 is a double-row heat exchanger, and the subcooling pipe section 52 is arranged below the heat exchange pipe section 51 and on the windward side of the outdoor unit condenser 5 (that is, Figure 1 the right side in).

[0046] By arranging the subcooling pipe section 52 on the windward side and below the heat exchange pipe section 51, the heat exchange capacity of the heat exchange pipe section 51 on the leeward side can be increased, the compressor power can be further reduced, frosting can be inhibited or the defrosting effect can be improved. This is because, generally, the temperature of the heat exchange medium in the subcooling pipe section after the first throttling is still higher than the ambient temperature. Before the second throttling, through the heat exchange between the subcooling pipe section 52 and the air flow, the heat released by the subcooling pipe section 52 is blown onto the heat exchange pipe section 51 on the leeward side by the air flow for heat exchange. The heat exchange medium in the heat exchange pipe section 51 on the leeward side has reached the low-temperature and low-pressure state after the second throttling, and the heat exchange pipes in the initial section are more likely to frost due to sufficient heat exchange. In this way, not only can the high-pressure side pressure be reduced to reduce the compressor power, but also the heat exchange effect of the heat exchange pipe section 51 can be ensured, achieving the effect of inhibiting frosting when there is no frost and effectively defrosting when frosting occurs, and greatly improving the overall energy efficiency.

[0047] Still referring to Figure 1 In a more preferred embodiment, the outdoor unit condenser 5 further includes a defrosting temperature detection element (not shown in the figure), which is arranged on the heat exchange pipe section 51, preferably at the initial section of the heat exchange pipe section 51. The defrosting temperature detection element can be connected to the controller of the variable-frequency air conditioner, so that the controller can control the opening and closing of the subcooling valves (55a, 55b) based on the temperature of the heat exchange pipe section 51 collected by the defrosting temperature detection element during the heating operation, that is, adjust the effective length of the subcooling pipe section 52. Among them, the defrosting temperature detection element can be a temperature sensor, a temperature sensing bulb, etc., which is attached to the outer surface of the initial section U-shaped pipe of the heat exchange pipe section 51 and is connected to the controller through a lead wire. Among them, the controller can be the controller of the air conditioner.

[0048] By arranging the defrosting temperature detection element at the initial section of the heat exchange pipe section 51, the controller can timely and reasonably adjust the opening and closing of the subcooling valves (55a, 55b) and the on-off valves (58a, 58b, 58c) based on the temperature of the heat exchange pipe section 51, so as to adjust the effective length of the subcooling pipe section 52, ensure the heat exchange effect of the superheat pipe section, inhibit frosting of the heat exchange pipeline, and improve the heating effect.

[0049] Continue to refer to Figure 1 In a more preferred embodiment, the outdoor unit condenser 5 further includes a subcooling temperature detection element (not shown in the figure), which is arranged on the subcooling pipe section 52 and can be connected to the controller of the variable-frequency air conditioner, so that the controller can control the opening degree of the first regulating valve 53 based on the temperature of the subcooling pipe section 52 collected by the subcooling temperature detection element during the heating operation. Among them, the subcooling temperature detection element can be a temperature sensor, a temperature sensing bulb, etc., which is attached to the outer surface of the U-shaped pipe of the subcooling pipe section 52 and is connected to the controller through a lead wire. Among them, the controller can be the controller of the air conditioner or a PID regulator, etc.

[0050] By providing a subcooling temperature detection element on the subcooling pipe section 52, the opening degree of the first regulating valve 53 can be adjusted based on the temperature of the subcooling pipe section 52, so that during heating, precise adjustment of the first regulating valve 53 can be achieved, the power of the compressor can be reduced, and the heating energy efficiency can be improved.

[0051] Continue to refer to Figure 1 , in a more preferred embodiment, the heat exchange pipe section 51 is divided into multiple flow paths, and the cross-section of the flow path is n-shaped and / or N-shaped. Specifically, in this embodiment, the heat exchange pipe section 51 has two flow paths, one of the cross-sections of the two flow paths is n-shaped and the other is N-shaped, and the flow directions of both are from the windward side to the leeward side. In this way, by dividing the heat exchange pipe section 51 into multiple flow paths, the refrigerant undergoes heat exchange simultaneously in multiple paths during the heat exchange process, ensuring the heat exchange efficiency and effect. By setting the flow directions of both flow paths to flow from the windward side to the leeward side, during the flow of the refrigerant, the temperature of the air flow after heat exchange with the refrigerant on the windward side increases, and then it undergoes heat exchange with the refrigerant on the leeward side, improving the heat exchange effect of the heat exchange pipe section 51 and also suppressing frosting.

[0052] Of course, those skilled in the art can understand that the above setting method is not fixed. Without departing from the principle of this application, those skilled in the art can adjust it as long as the adjustment satisfies dividing the heat exchange pipe section 51 into multiple flow paths, and the cross-section of each flow path is n-shaped and / or N-shaped. For example, the flow paths can also be divided into three or more, and the cross-section of each flow path is N-shaped or n-shaped, etc.

[0053] In a more preferred embodiment, both the first regulating valve 53 and the second regulating valve 7 are electronic expansion valves in this embodiment. The first regulating valve 53 is set to be fully open when the variable-frequency air conditioner operates in the cooling mode and to open a set opening degree when operating in the heating mode. The second regulating valve 7 is set to open according to the required throttling opening degree during both cooling and heating. The settings of the first regulating valve 53 and the second regulating valve 7 enable the variable-frequency air conditioner to precisely adjust the subcooling degree of the system by adjusting the opening degrees of the two regulating valves during the heating process, thereby reducing the heating power and improving the heating energy efficiency.

[0054] Although both the first regulating valve 53 and the second regulating valve 7 adopt electronic expansion valves in this embodiment, this is not restrictive. Those skilled in the art can change them based on the specific application scenario. For example, the first regulating valve 53 and / or the second regulating valve 7 can also adopt electronically controlled valves such as solenoid valves.

[0055] Next, refer to Figure 2, and a second embodiment of the variable-frequency air conditioner of the present application is described in combination with three subcooling valves (55a, 55b, 55c) provided on the subcooling pipe section 52.

[0056] As Figure 2 shown, in a more preferred embodiment, the three subcooling valves (55a, 55b, 55c) divide the subcooling pipe section 52 into four subcooling intervals. The first to the third subcooling intervals from bottom to top in the four subcooling intervals are each connected to the first end of the first regulating valve 53 through a subcooling connecting pipe 54. Among them, an on-off valve (58a, 58b, 58c) is also provided on each subcooling connecting pipe 54. By controlling the opening and closing of the subcooling valves (55a, 55b, 55c) and the on-off valves (58a, 58b, 58c), the effective length of the subcooling pipe section 52 can be controlled. In particular, the second end of the subcooling pipe section 52 is also connected to the heat exchange pipe section 51. The outdoor unit condenser 5 further includes three confluence connecting pipes 56 and three confluence valves (57a, 57b, 57c). The second to the fourth subcooling intervals from bottom to top in the four subcooling intervals are each connected to the second end of the first regulating valve 53 through a confluence connecting pipe 56, and a confluence valve (57a, 57b, 57c) is also provided on each confluence connecting pipe 56. In this way, during the heating process, by jointly controlling the subcooling valves (55a, 55b, 55c), the confluence valves (57a, 57b, 57c) and the on-off valves (58a, 58b, 58c), the effective length of the subcooling pipe section 52 can be adjusted, and the remaining pipeline outside the effective length of the subcooling pipe section 52 can be connected to the heat exchange pipe section 51 through the confluence connecting pipe 56 and the confluence valve to participate in evaporation heat exchange.

[0057] For example, when the subcooling valve 55a is closed, 55b and 55c are opened, the on-off valve 58a is opened, 58b and 58c are closed, and the confluence valve 57a is opened, 57b and 57c are closed, the effective length of the subcooling pipe section 52 is close to the first end of the subcooling pipe section 52 ( Figure 1the length of the first subcooling interval at the lower end of [], while the second and fourth subcooling intervals are connected to the heat exchange tube section 51. The part of the refrigerant flowing out from the second end of the first regulating valve 53 flows through the confluence valve 57a and successively through the second to fourth subcooling intervals and then into the heat exchange tube section 51. When the subcooling valve 55b is closed, 55a and 55c are opened, the on-off valve 58b is opened, the on-off valves 58a and 58c are closed, and the confluence valve 55b is opened, 55a and 55c are closed, the effective length of the subcooling tube section 52 is the sum of the lengths of the first and second subcooling intervals starting from the first end of the subcooling tube section 52, while the third and fourth subcooling intervals are connected to the heat exchange tube section 51, and so on. Among them, the subcooling valves (55a, 55b, 55c), the confluence valves (57a, 57b, 57c), and the on-off valves (58a, 58b, 58c) can also be electrically controlled valves such as solenoid valves and electronic expansion valves.

[0058] Through the settings of the subcooling valves (55a, 55b, 55c), the confluence valves (57a, 57b, 57c), and the on-off valves (58a, 58b, 58c), during heating, it is possible to jointly adjust the opening and closing of the subcooling valves (55a, 55b, 55c), the confluence valves (57a, 57b, 57c), and the on-off valves (58a, 58b, 58c) to cleverly adjust the effective length of the subcooling tube section 52 and the effective length of part of the heat exchange tube section 51, so as to suppress frosting or defrost the outdoor unit condenser 5 by changing the effective length of the subcooling tube section 52, improve the heating efficiency, reasonably utilize the remaining pipeline of the subcooling tube section 52 to supplement the heat exchange tube section 51, and improve the evaporation heat exchange effect of the heat exchange tube section 51.

[0059] Of course, those skilled in the art can understand that in the first and second embodiments, the number and setting methods of the subcooling valves (55a, 55b, 55c), the confluence valves (57a, 57b, 57c), and the on-off valves (58a, 58b, 58c) are not restrictive. Without departing from the principle of this application, those skilled in the art can adjust the above methods so that this application can be applied to more specific application scenarios.

[0060] For example, although the above-mentioned first and second embodiments are described in combination with the setting of two subcooling valves (55a, 55b) and three subcooling valves (55a, 55b, 55c), it is obvious that the number of subcooling valves is not limited to this. Those skilled in the art can reasonably adjust its number. For example, the subcooling valve can also be set to one, four or more. Similarly, the numbers of the confluence valves (57a, 57b, 57c) and the on-off valves (58a, 58b, 58c) can also be adjusted as long as the adjustment conforms to the principle of this application, and details will not be elaborated here.

[0061] For another example,Figure 3 and Figure 4 respectively show partial schematic diagrams of the third and fourth embodiments of the variable-frequency air conditioner of the present application. As Figure 3 shown, those skilled in the art can also, on the basis of Embodiment 1 or 2, omit the setting of the on-off valves (58a, 58b, 58c), and instead effectively guide the refrigerant by reasonably setting the radian of the subcooling connecting pipe 54 to prevent the refrigerant from flowing back during the refrigeration or heating process. As Figure 4 shown, those skilled in the art can also, on the basis of Embodiment 1 or 2, replace the on-off valves (58a, 58b, 58c) with check valves and only set them on some of the subcooling pipelines to prevent the phenomenon of refrigerant flowing back during the heating process.

[0062] Of course, the above-mentioned various replaceable embodiments can be used in cross-combination with each other, and the replaceable embodiments and the preferred embodiments can also be used in cross-combination to combine new embodiments to be applicable to more specific application scenarios. For example, the third embodiment and the fourth embodiment are combined, and on the basis of reasonably setting the radian of the subcooling connecting pipe 54, check valves are added to some of the subcooling connecting pipes 54.

[0063] Next, in combination with Figure 2 a brief description of the working process of the variable-frequency air conditioner of the present invention will be given.

[0064] As Figure 2 shown, when the variable-frequency air conditioner operates in the refrigeration mode, the first regulating valve 53 is fully opened, the second regulating valve 7 is opened to a set opening degree, all the subcooling valves (55a, 55b, 55c) are fully opened, all the converging valves (57a, 57b, 57c) and the on-off valves (58a, 58b, 58c) are fully closed. After the refrigerant is discharged from the exhaust port of the variable-frequency compressor 1, it enters the outdoor unit condenser 5 and simultaneously flows through the n-type flow path and the N-type flow path of the heat exchange pipe section 51 to perform condensation heat exchange with the outdoor air, and then converges into a single flow path after the first regulating valve 53. Then, the refrigerant enters the indoor unit evaporator 3 through the throttling of the second regulating valve 7 to perform evaporation heat exchange with the indoor air, and the heat-exchanged refrigerant returns to the variable-frequency compressor 1 from the suction port of the variable-frequency compressor 1 to complete a refrigeration cycle.

[0065] When the variable-frequency air conditioner operates in the heating mode, the first regulating valve 53 and the second regulating valve 7 are each opened to a set opening degree, the subcooling valves 55a are closed, 55b and 55c are opened, the on-off valves 58a are opened, 58b and 58c are closed, the confluence valves 57a are opened, 57b and 57c are closed. After the refrigerant is discharged from the exhaust port of the variable-frequency compressor 1, it first enters the indoor unit evaporator 3 to perform condensation heat exchange with the indoor air. The refrigerant after heat exchange undergoes the first throttling and temperature reduction through the second regulating valve 7, and then enters the first subcooling interval of the subcooling pipe section 52 of the outdoor unit condenser 5. The temperature of the refrigerant entering the first subcooling interval is still relatively high. At this time, after further condensation heat exchange with the outdoor air, under the secondary throttling of the first regulating valve 53, a part of the refrigerant passes through the I-shaped heat exchange pipe section 51 and the confluence connecting pipe 56 after the first regulating valve 53 and then enters the second to fourth subcooling intervals of the subcooling pipe section 52, and then enters the N-shaped flow path of the heat exchange pipe section 51 to perform evaporation heat exchange with the outdoor air. Another part of the refrigerant passes through the I-shaped heat exchange pipe section 51 after the first regulating valve 53 and enters the n-shaped flow path of the heat exchange pipe section 51 to perform evaporation heat exchange with the outdoor air. After the heat-exchanged refrigerant converges into one flow path, it returns to the variable-frequency compressor 1 from the suction port of the variable-frequency compressor 1 to complete a heating cycle. Among them, during the heat exchange process, the temperature of the air flow after heat exchange with the subcooling pipe section 52 and the windward-side heat exchange pipe section 51 increases, and then heat exchange is performed with the I-shaped heat exchange pipe section 51 on the leeward side to inhibit frosting. If it is determined through the temperature acquisition of the frost formation temperature detection element that the I-shaped heat exchange pipe section 51 frosts during the heating process, then the opening and closing of the subcooling valves (55a, 55b, 55c), the on-off valves (57a, 57b, 57c), and the confluence valves (58a, 58b, 58c) are reasonably controlled to change the effective length of the subcooling pipe section 52 and the effective length of part of the heat exchange pipe section 51, and defrosting is quickly performed by increasing the effective length of the subcooling pipe section 52.

[0066] Of course, those skilled in the art can also change the above control process. For example, during the refrigeration operation, it is also possible to achieve the purpose of converging the refrigerant into one path before the first regulating valve 53 and further performing subcooling through part of the subcooling pipe section by closing the subcooling valves 55a, opening 55b and 55c, opening the on-off valves 58a, closing 58b and 58c, and opening the confluence valves 57a, closing 57b and 57c.

[0067] Those skilled in the art can understand that although some of the embodiments described herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of the present invention and forms different embodiments. For example, in the claims of the present invention, any one of the claimed embodiments can be used in any combination.

[0068] Example 2

[0069] The following is a reference to Figure 2 and Figure 5 to introduce the heating control method of the air conditioner of the present application. Among them, Figure 5 is a flowchart of the control method of the air conditioner of the present invention.

[0070] As Figure 5 shown, corresponding to the above variable-frequency air conditioner, the present application also provides a control method for a variable-frequency air conditioner. The specific structure of the variable-frequency air conditioner has been introduced in Embodiment 1 and will not be elaborated here. The control method includes:

[0071] S100. When in heating operation, obtain the outdoor ambient temperature; for example, when the air conditioner is in heating operation, obtain the outdoor ambient temperature through a temperature sensor arranged on the outdoor unit.

[0072] S200. Compare the size of the outdoor ambient temperature with the temperature threshold; for example, the temperature threshold is the temperature that can reflect whether the outdoor unit is prone to frosting. For example, the temperature threshold is 5°C. After obtaining the outdoor ambient temperature, compare the outdoor ambient temperature with 5°C. Of course, the above temperature threshold is only an example. Those skilled in the art can adjust it based on the specific application scenario, such as adjusting it based on test or empirical values, as long as this temperature value can be used as a critical value to reflect whether the outdoor unit is prone to frosting.

[0073] S300. When the outdoor ambient temperature is less than the temperature threshold, obtain the temperature of the heat exchange pipe section 51; for example, still taking the temperature threshold of 5°C as an example, when the outdoor ambient temperature is less than 5°C, it proves that the outdoor unit is prone to frosting at this time. At this time, it is necessary to obtain the temperature of the heat exchange pipe section 51 for further analysis to determine whether the heat exchange pipe section 51 has frosted.

[0074] S400. Based on the temperature of the heat exchange pipe section 51, selectively adjust the opening and closing of several sub-cooling valves (55a, 55b, 55c) to adjust the effective length of the sub-cooling pipe section 52; for example, when the temperature of the heat exchange pipe section 51 continuously drops below a certain temperature value, it proves that the heat exchange pipe section 51 has frosted. At this time, it is necessary to adjust the opening and closing of several sub-cooling valves (55a, 55b, 55c) to adjust the effective length of the sub-cooling pipe section 52, that is, to adjust the number of sub-cooling intervals in the sub-cooling pipe section 52 that play a sub-cooling role, so as to improve the defrosting ability of the outdoor unit condenser 5 and defrost the outdoor unit condenser 5 in time. Among them, the method of adjusting the effective length of the sub-cooling pipe section 52 has been introduced in Embodiment 1 and will not be elaborated here.

[0075] S500. Determine the operating opening of the first regulating valve 53. For example, the operating opening can be determined based on the correspondence between the current temperature of the subcooling pipe section 52 and the opening of the first regulating valve 53, or it can be determined based on the fitting formula between parameters such as the outdoor ambient temperature and the first regulating valve 53, etc.

[0076] S600. Adjust the opening of the first regulating valve 53 to the operating opening. After determining the operating opening of the first regulating valve 53, control the first regulating valve 53 to adjust to this operating opening to ensure that the air conditioner operates in a better state.

[0077] By selectively adjusting the opening and closing of the subcooling valves (55a, 55b, 55c) according to the temperature of the heat exchange pipe section 51 when the outdoor ambient temperature is less than the temperature threshold, thereby adjusting the effective length of the subcooling pipe section 52, the control method of the present application can effectively improve the heating effect of the air conditioner, improve the heating energy efficiency of the air conditioner, inhibit frosting and effectively defrost. Specifically, usually when the outdoor ambient temperature is less than the temperature threshold, especially in a low-temperature and high-humidity outdoor environment, the outdoor unit condenser 5 of the air conditioner is extremely prone to frosting during the heating operation. After frosting, it will seriously affect the heating efficiency of the air conditioner and reduce the heating energy efficiency. The present application sets the first regulating valve 53 between the heat exchange pipe section 51 and the subcooling pipe section 52, and uses a plurality of subcooling valves (55a, 55b, 55c) to divide the subcooling pipe section 52 into multiple subcooling intervals. In this way, through the secondary throttling of the first regulating valve 53, the outdoor subcooling pipe section 52 can be used as a supplement to the indoor evaporator for condensation heat exchange during the heating process, so that the hot air flow after the condensation heat exchange can exchange heat with the heat exchange pipe section 51 again, which can not only inhibit the frosting of the heat exchange pipe section 51, but also defrost in time when the heat exchange pipe section 51 is frosted. On this basis, by controlling the opening and closing of different subcooling valves (55a, 55b, 55c), the number of subcooling intervals that play a subcooling role in the subcooling pipe section 52 can be controlled, the effective length of the subcooling pipe section 52 can be adjusted, and then the frosting degree and defrosting effect can be controlled. By determining the operating opening of the first regulating valve 53 during the heating process and adjusting its opening to the operating opening, when the air conditioner is heating, the temperature of the subcooling pipe section 52 can be made to reach a better temperature by controlling the opening of the first regulating valve 53, so as to accurately control the subcooling degree of the air conditioning system, make the heating effect of the air conditioner reach the best, and improve the heating energy efficiency.

[0078] It should be noted that although the above steps S500 and S600 are described in combination after adjusting the opening and closing of the subcooling valve, their execution timing is not fixed. Those skilled in the art can adjust them, and such adjustment does not deviate from the protection scope of the present application. For example, the above steps S500 and S600 can also be performed before adjusting the opening and closing of the subcooling valve, or can be run before or after other steps.

[0079] It should also be noted that although it is determined that frosting occurs in the heat exchange pipe section 51 when the outdoor ambient temperature is less than the temperature threshold in the above-mentioned embodiment, this is not the only condition for judging frosting. Those skilled in the art can understand that other judgment conditions can be added to jointly judge whether the subcooled pipe section 52 is frosted. For example, on the basis of temperature judgment, humidity judgment is added. When both the temperature and humidity are less than a certain threshold, it is determined that frosting occurs in the subcooled pipe section 52.

[0080] The control method of the present application will be introduced in detail below.

[0081] In a preferred embodiment, before step S400, the control method of the air conditioner further includes: adjusting the opening and closing of a plurality of subcooling valves (55a, 55b, 55c) to make the effective length of the subcooled pipe section 52 the shortest. Specifically, the effective length of the subcooled pipe section 52 can be controlled to be the shortest when entering the heating mode, or when it is determined that the outdoor ambient temperature is less than the temperature threshold or any other timing prior to collecting the temperature of the heat exchange pipe section 51. For example, referring to Figure 2 the embodiment shown, controlling the effective length of the subcooled pipe section 52 to be the shortest means controlling the number of subcooling intervals in the subcooled pipe section 52 that can play a subcooling role to be the smallest. In other words, by controlling the subcooling valve closest to the first end of the subcooled pipe section 52 to be closed and the remaining subcooling valves to be open, controlling the on-off valve closest to the first end of the subcooled pipe section 52 to be open and the remaining on-off valves to be closed, and controlling the confluence valve closest to the second end of the first regulating valve 53 to be open and the remaining confluence valves to be closed, that is, controlling the subcooling valve 55a to be closed, 55b and 55c to be open, the confluence valve 57a to be open, 57b and 57c to be closed, and the on-off valve 58a to be open, 58b and 58c to be closed. At this time, the effective length of the subcooled pipe section 52 is the length of the first subcooling interval starting from the first end of the subcooled pipe section 52 ( Figure 2 the lower end shown).

[0082] In a preferred embodiment, step S400 may further include: obtaining and recording the temperature of the heat exchange tube section 51 every set time period; calculating the temperature change rate of the heat exchange tube section 51 within the set time period based on the temperature and the set time period; comparing the magnitude of the temperature change rate with a set threshold; when the temperature change rate is greater than the set threshold and lasts for a preset time, adjusting the opening and closing of several subcooling valves (55a, 55b, 55c) to increase the effective length of the subcooling tube section 52 until the effective length of the subcooling tube section 52 increases to the maximum; simultaneously with, before or after adjusting the opening and closing of several subcooling valves (55a, 55b, 55c), adjusting the opening and closing of several confluence valves (57a, 57b, 57c) to connect the part outside the effective length to the heat exchange tube section 51; and simultaneously with, before or after adjusting the opening and closing of several on-off valves (58a, 58b, 58c), adjusting the opening and closing of several on-off valves (58a, 58b, 58c) to cut off the connection between the part outside the effective length and the effective length.

[0083] Specifically, the set time period can be any value between 2 min and 5 min, or other values. After obtaining and recording the temperature of the heat exchange tube section 51 within the set time period, the temperature change rate of the heat exchange tube section 51 within the set time period can be calculated based on the following formula (1):

[0084]

[0085] In formula (1), K is the temperature change rate of the heat exchange tube section 51 within the set time period; T n is the temperature at the nth sampling point within the set time period, T n-1 is the temperature at the (n - 1)th sampling point within the set time period, and t is the time interval between the nth sampling point and the (n - 1)th sampling point.

[0086] When it is calculated that the temperature change rate is less than or equal to a certain set threshold and lasts for a preset time, for example, when the set threshold is -1 and the preset time is 1 min, when K ≤ -1 and lasts for 1 min, it proves that the heat exchange tube section 51 is rapidly frosting at this time, resulting in a continuous decrease in the coil temperature. Moreover, the heat flow brought by the current effective length of the subcooling tube section 52 is insufficient to defrost the heat exchange tube section 51, and the defrosting ability needs to be improved. At this time, by adjusting the opening and closing of the subcooling valves (55a, 55b, 55c), the confluence valves (57a, 57b, 57c) and the on-off valves (58a, 58b, 58c), the effective length of the subcooling tube section 52 can be increased, the heat exchange length of the subcooling tube section 52 can be increased, thereby improving the defrosting ability, and at the same time connecting the part outside the effective length to the heat exchange tube section 51. For example, still taking Figure 2Taking the air conditioner shown as an example, when the effective length of the subcooling pipe section 52 is the shortest, by controlling the subcooling valve 55b to close, 55a and 55c to open, the confluence valve 57b to open, 57a and 57c to close, and the on-off valve 58b to open, 58a and 58c to close, the effective length of the subcooling pipe section 52 is increased to the sum of the lengths of the first and second subcooling intervals starting from the first end of the subcooling pipe section 52, while connecting the third to fourth subcooling intervals to the heat exchange pipe section 51 and truncating the connection between the third to fourth subcooling intervals and the first to second subcooling intervals. And so on until the effective length of the subcooling pipe section 52 increases to the maximum. Conversely, when the calculated temperature change rate K > -1 or the time when K ≤ -1 does not last for 1 minute, it proves that the heat exchange pipe section 51 is not frosted or the frosting is not serious at this time, and its heat exchange effect is good. Therefore, there is no need to adjust the subcooling valves (55a, 55b, 55c), and only need to control the subcooling valves (55a, 55b, 55c) to maintain the current state.

[0087] By adjusting the effective length of the subcooling pipe section 52 based on the temperature change rate at each set time period, the control method of the present application can also adjust the defrosting ability accordingly based on the frosting condition of the current heat exchange pipe section 51, improve the defrosting effect, avoid the situation where the defrosting ability does not match the frosting degree, and ensure the heating efficiency. By adjusting the opening and closing of the confluence valve (57a, 57b, 57c) at the same time as, before or after adjusting the opening and closing of the subcooling valve (55a, 55b, 55c) so that the part outside the effective length is connected to the heat exchange pipe section 51, the control method of the present application can also reasonably utilize the part outside the effective length as a supplement to the heat exchange pipe section 51 to improve the evaporation heat exchange effect. By adjusting the opening and closing of the on-off valve (58a, 58b, 58c) at the same time as, before or after adjusting the opening and closing of the subcooling valve (55a, 55b, 55c) to truncate the connection between the part outside the effective length and the effective length, the control method of the present application can also improve the utilization rate of the refrigerant in the subcooling pipe section 52 and ensure the heat exchange efficiency.

[0088] Of course, the above embodiments are introduced in combination with Figure 2 the air conditioner shown. Those skilled in the art can understand that when the setting mode of the air conditioner is other forms, the above embodiments can be adjusted accordingly, appropriately adding or deleting some steps so that the control method of the present application can have better applicability. For example, when the air conditioner is in the setting mode as Figure 1 shown, the step of adjusting the opening and closing of the confluence valve (57a, 57b, 57c) can be omitted; when the air conditioner is in the setting mode as Figure 3 or Figure 4When the setting method shown is adopted, the steps of adjusting the opening and closing of the on-off valves (58a, 58b, 58c) can be omitted; when only the subcooling valves (55a, 55b, 55c) are set in the air conditioner, the steps of adjusting the opening and closing of the manifold valves (57a, 57b, 57c) and the on-off valves (58a, 58b, 58c) can be omitted at the same time, etc.

[0089] Furthermore, in addition to the method of comparing the temperature change rate with the set threshold value, other methods can also be used to obtain the conclusion of whether the superheat pipe section is frosted. These methods do not deviate from the principle of this application, so they should reasonably fall within the protection scope of this application. For example, the method of rounding down the temperature change rate K and judging whether the result is less than the set threshold value, that is, judging whether Int(K) is less than the set threshold value (such as whether it is less than 0), can also be used to judge whether the heat exchange pipe section 51 is frosted, or by integrating the temperature change amount within the set time period and calculating the size of the integral result and the set value to judge whether the heat exchange pipe section 51 is frosted, etc.

[0090] In a preferred embodiment, the first regulating valve 53 is a solenoid valve or an electronic expansion valve, etc. The step S500 further includes: obtaining the outdoor ambient temperature and the operating frequency of the compressor; calculating the theoretical temperature of the subcooling pipe section 52 based on the outdoor ambient temperature; calculating the operating opening of the first regulating valve 53 based on the outdoor ambient temperature, the operating frequency and the theoretical temperature.

[0091] For example, the outdoor ambient temperature can be obtained through a temperature sensor provided on the outdoor unit, and the operating frequency of the compressor can be obtained based on the operating parameters when the variable-frequency air conditioner is running. Then, the following formula (2) is used to calculate the theoretical temperature of the subcooling pipe section 52:

[0092] T c =k×T ao +p (2)

[0093] In formula (2), T c is the theoretical temperature of the subcooling pipe section 52; T ao is the outdoor ambient temperature; k and p are constants, and these constants can be obtained by fitting based on experimental data. For example, the air conditioner is experimented multiple times for different outdoor ambient temperatures. In the experiment, based on different outdoor ambient temperatures, by adjusting the temperature of the subcooling pipe section 52 to make the heat exchange effect the best under this condition, and recording the temperature of the subcooling pipe section 52 when the heat exchange effect is the best as the theoretical temperature under this condition. After multiple tests, the values of the constants k and p are calculated by using the linear fitting method, so as to obtain the fitting formula between the outdoor ambient temperature and the theoretical temperature of the subcooling pipe section 52.

[0094] Those skilled in the art can understand that the theoretical temperature of the subcooled pipe section 52 determines the heat exchange effect and defrosting effect of the subcooled pipe section 52, indirectly determines the heating energy efficiency, and the heat exchange effect of the subcooled pipe section 52 is directly related to the outdoor ambient temperature. When the temperature difference between the outdoor ambient temperature and the subcooled pipe section 52 reaches a certain range, the subcooling degree of the air conditioning system also reaches a better state. By calculating the theoretical temperature of the subcooled pipe section 52 based on the outdoor ambient temperature, the control method of the present application can associate the theoretical temperature of the subcooled pipe section 52 with the outdoor ambient temperature, reduce the power of the compressor, and improve the heating efficiency on the basis of ensuring the best subcooling degree and subcooling effect of the outdoor heat exchanger.

[0095] Of course, the determination of the theoretical temperature is not limited to the method shown in the above formula (2). Under the condition of not deviating from the principle of the present application, any method of determining the theoretical temperature of the subcooled pipe section 52 through the outdoor ambient temperature can replace formula (2). For example, the specific value of the theoretical temperature can also be determined through the correspondence between the outdoor ambient temperature and the theoretical temperature of the subcooled pipe section 52.

[0096] In a more preferred embodiment, the following fitting formula (3) can be used to calculate the operating opening of the first regulating valve 53:

[0097] B = a1×f + b1×T ao + c1×Int(T c - T ao ) (3)

[0098] In formula (3), B is the operating opening of the first regulating valve 53; f is the operating frequency of the compressor; T c is the theoretical temperature of the subcooled pipe section 52; T ao is the outdoor ambient temperature; Int(T c - T ao ) is the floor function operation on the difference between the theoretical temperature of the subcooled pipe section 52 and the outdoor ambient temperature; a1, b1, and c1 are constants, and these constants can be obtained by fitting based on experimental data. For example, multiple experiments are conducted on the heating energy efficiency of the air conditioner for different outdoor ambient temperatures, compressor frequencies, and theoretical temperatures of the subcooled pipe section 52. In the experiment, the opening of the first regulating valve 53 is adjusted to make the heating energy efficiency of the air conditioner the lowest, and the opening parameter of the first regulating valve 53 corresponding to the current heating energy efficiency is recorded as the operating opening of the first regulating valve 53 under this condition. After multiple tests, the values of the constants a1, b1, and c1 are calculated, so as to obtain the fitting formula between the first regulating valve 53 and the outdoor ambient temperature, compressor frequency, and theoretical temperature of the subcooled pipe section 52.

[0099] By jointly determining the opening degree of the first regulating valve 53 based on the operating frequency of the compressor, the theoretical temperature of the subcooling pipe section 52, and the outdoor ambient temperature, the control method of the present application can jointly determine the opening degree of the first regulating valve 53 based on multiple variables, improve the calculation accuracy of the opening degree, enable the first regulating valve 53 to always work at an appropriate opening degree, and reduce the heating energy consumption of the air conditioner.

[0100] Of course, the determination of the opening degree of the first regulating valve 53 can also be based on other relationships between it and the above parameters, such as the fixed correspondence relationship between the above three parameters and the opening degree, etc.

[0101] In a more preferred embodiment, after "adjusting the opening degree of the first regulating valve 53 to the operating opening degree", the heating control method further includes: obtaining the actual temperature of the subcooling pipe section 52; performing PID adjustment on the opening degree of the first regulating valve 53 based on the difference between the theoretical temperature and the actual temperature.

[0102] By performing PID control on the opening degree of the first regulating valve 53 based on the difference between the theoretical temperature and the actual temperature of the subcooling pipe section 52 after adjusting the opening degree of the first regulating valve 53 to the operating opening degree, the control method of the present application can also dynamically, quickly, and accurately adjust the opening degree of the first regulating valve 53, preventing the problem of over-adjustment or overshoot of the first regulating valve 53.

[0103] In a more preferred embodiment, after step S600, the control method further includes: obtaining the outdoor ambient temperature and the operating frequency of the compressor; calculating the heating target exhaust temperature of the air conditioner based on the outdoor ambient temperature and the operating frequency; controlling the opening degree of the second regulating valve 7 based on the heating target exhaust temperature. Preferably, the above steps can be performed after performing PID adjustment on the opening degree of the first regulating valve 53, that is, during the process of performing PID adjustment on the opening degree of the first regulating valve 53, when the actual temperature of the subcooling pipe section 52 reaches the theoretical temperature, obtain the outdoor ambient temperature and the operating frequency of the compressor, calculate the heating target exhaust temperature based on the outdoor ambient temperature and the operating frequency of the compressor, and control the opening degree of the second regulating valve 7 based on this. Among them, the following formula (4) can be used to calculate the heating target exhaust temperature of the air conditioner:

[0104] T target_heat = a2×f + b2×(T ao - 7) + c2 (4)

[0105] In formula (4), T target_heat is the heating target exhaust temperature of the air conditioner; f is the operating frequency of the compressor; T ao is the outdoor ambient temperature; a2, b2, c2 are constants, and these constants can be obtained by fitting based on experimental data. The obtaining method is similar to the above and will not be elaborated here.

[0106] Those skilled in the art can understand that the opening degree of the second regulating valve 7 directly determines the effect of the first throttling and temperature reduction during the heating process. Coupled with the control of the first regulating valve 53, the two jointly determine the energy efficiency of the heating operation. The control method of the present application performs linkage control on the first regulating valve 53 and the second regulating valve 7 during heating, especially adjusts the opening degree of the second regulating valve 7 on the basis of controlling the first regulating valve 53, so that the operating parameters of the air conditioner can always be maintained in the optimal state, ensuring the operating effect of the air conditioner while also improving the energy efficiency of the air conditioner.

[0107] Of course, the determination of the heating target exhaust temperature is not limited to the method shown in the above formula (4). Without departing from the principle of the present application, any method of determining the heating target exhaust temperature through the outdoor ambient temperature and the operating frequency of the compressor can replace formula (4). Furthermore, there are already various solutions in the prior art for the method of controlling the second regulating valve 7 based on the heating target exhaust temperature, such as proportional regulation, PID regulation, etc. These solutions can all be applied to the control method of the present application and will not be elaborated here. In addition, although in this embodiment, the sequence of controlling the opening degree of the second regulating valve 7 after performing PID control on the first regulating valve 53 is described, this control method is not absolute. Performing PID control on the first regulating valve 53 is only a verification step to prevent overshoot or overregulation of the first regulating valve 53, and this step is not necessary. Therefore, theoretically, controlling the opening degree of the second regulating valve 7 simultaneously with or before performing PID control on the first regulating valve 53 can also improve the heating energy efficiency.

[0108] In a more preferred embodiment, the control method further includes:

[0109] When the air conditioner operates in the cooling mode, control the first regulating valve 53 to be fully open; obtain the outdoor ambient temperature and the operating frequency of the compressor; calculate the cooling target exhaust temperature of the air conditioner based on the outdoor ambient temperature and the operating frequency; control the opening degree of the second regulating valve 7 based on the cooling target exhaust temperature. Among them, the following formula (5) can be used to calculate the cooling target exhaust temperature of the air conditioner:

[0110] T target_cool = a3×f + b3×(T ao - 35) + c3 (5)

[0111] In formula (5), T target_cool is the cooling target exhaust temperature of the air conditioner; f is the operating frequency of the compressor; T ao is the outdoor ambient temperature; a3, b3, and c3 are constants, and these constants can be obtained by fitting based on experimental data. The method of obtaining them is similar to the above and will not be elaborated here.

[0112] When the air conditioner is in the refrigeration mode, fully opening the first regulating valve 53 can avoid the influence of the first regulating valve 53 on the refrigeration energy efficiency. By adjusting the opening degree of the second regulating valve 7 based on the refrigeration target exhaust temperature, normal regulation of the air conditioner can be achieved, ensuring the refrigeration effect and refrigeration energy efficiency.

[0113] Of course, similarly to the above, the determination of the refrigeration target exhaust temperature is not limited to the method shown in the above formula (5). Under the condition of not deviating from the principle of this application, any method of determining the refrigeration target exhaust temperature through the outdoor ambient temperature and the operating frequency of the compressor can replace formula (5). Furthermore, there are already various existing schemes for controlling the second regulating valve 7 based on the refrigeration target exhaust temperature, such as proportional regulation, PID regulation, etc. These schemes can all be applied to the control method of this application, so they will not be elaborated here.

[0114] The following combines Figure 2 and Figure 6 to briefly introduce the control process of the control method of the air conditioner of this application. Among them, Figure 6 is the logic diagram of the control method of the air conditioner of the present invention.

[0115] As Figure 2 and Figure 6 shown, in a possible implementation process, the air conditioner operates in the heating mode → first obtain the outdoor ambient temperature T ao , and determine whether T ao < 5°C holds:

[0116] If T ao < 5°C does not hold, adjust the effective length of the subcooling pipe section 52 to the shortest (if it is already in the shortest state, no adjustment is required), and maintain this state for continuous operation → obtain the outdoor ambient temperature T ao and the operating frequency f of the compressor during the operation → calculate the theoretical temperature T c of the subcooling pipe section 52 based on formula (2) → calculate the operating opening degree B of the first regulating valve 53 based on formula (3) → control the first regulating valve 53 to open to the opening degree B, so that the air conditioner operates with better heating energy efficiency and defrosting efficiency → after the air conditioner operates for 2 minutes, detect the actual temperature T c1 of the subcooling pipe → calculate the difference △T between the theoretical temperature T c and the actual temperature T c1 , and perform PID precise adjustment on the opening degree of the first regulating valve 53 based on this difference △T to ensure the heating energy efficiency of the air conditioner and prevent over-adjustment or overshoot of the first regulating valve 53 → during the PID adjustment process, determine whether the actual temperature of the subcooling pipe section 52 reaches the theoretical temperature → when the actual temperature reaches the theoretical temperature, obtain the outdoor ambient temperature T aoand the operating frequency f of the compressor, and calculate the heating target exhaust temperature T based on formula (4). target_heat → Based on the heating target exhaust temperature T target_heat Control the opening degree of the second regulating valve 7 to make the operating state and heating efficiency of the air conditioner reach the best.

[0117] If T ao <5°C holds, first adjust the effective length of the subcooling pipe section 52 to the shortest, continuously detect the temperature of the heat exchange pipe section 51 within a set time period of 2 minutes, and calculate the temperature change rate K within these 2 minutes based on formula (1) → If K ≤ -1 and lasts for 1 minute, control the opening and closing of the subcooling valves (55a, 55b, 55c), the confluence valves (57a, 57b, 57c), and the on-off valves (58a, 58b, 58c) to increase the effective length of the subcooling pipe section 52 → After increasing the effective length of the subcooling pipe section 52, obtain the outdoor ambient temperature T ao and the operating frequency f of the compressor → Calculate the theoretical temperature T of the subcooling pipe section 52 based on formula (2). c → Based on formula (3), calculate the operating opening degree B of the first regulating valve 53 → Control the first regulating valve 53 to open to the opening degree B, so that the air conditioner operates with better heating energy efficiency and defrosting efficiency → After the air conditioner operates for 2 minutes, detect the actual temperature T of the subcooling pipe. c1 → Calculate the theoretical temperature T c and the actual temperature T c1 The difference △T between them, and perform PID precise adjustment on the opening degree of the first regulating valve 53 based on this difference △T to ensure the heating energy efficiency of the air conditioner and prevent over-adjustment or overshoot of the first regulating valve 53 → During the PID adjustment process, judge whether the actual temperature of the subcooling pipe section 52 reaches the theoretical temperature → When the actual temperature reaches the theoretical temperature, obtain the outdoor ambient temperature T ao and the operating frequency f of the compressor, and calculate the heating target exhaust temperature T based on formula (4). target_heat → Based on the heating target exhaust temperature T target_heat Control the opening degree of the second regulating valve 7 to make the operating state and heating efficiency of the air conditioner reach the best → After the adjustment is completed, return to repeat the steps of collecting the temperature of the heat exchange pipe section 51, adjusting the effective length of the subcooling pipe based on the temperature change rate K, and adjusting the opening degree B of the first regulating valve 53 until the effective length of the subcooling pipe section 52 increases to the maximum.

[0118] Those skilled in the art can understand that the above variable-frequency air conditioner also includes some other well-known structures, such as a processor, a controller, a memory, etc. Among them, the memory includes but is not limited to random access memory, flash memory, read-only memory, programmable read-only memory, volatile memory, non-volatile memory, serial memory, parallel memory, or registers, etc. The processor includes but is not limited to CPLD / FPGA, DSP, ARM processor, MIPS processor, etc. In order not to unnecessarily obscure the embodiments of the present disclosure, these well-known structures are not shown in the drawings.

[0119] Each component embodiment of the present invention can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art should understand that a microprocessor or a digital signal processor (DSP) can be used in practice to implement some or all of the functions of some or all of the components in the server and client according to the embodiments of the present invention. The present invention can also be implemented as a device or apparatus program (for example, a PC program and a PC program product) for executing part or all of the methods described herein. Such a program implementing the present invention can be stored on a PC-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0120] It should be noted that although the detailed steps of the method of the present invention are described in detail above, on the premise of not deviating from the basic principle of the present invention, those skilled in the art can combine, split, and change the order of the above steps. The technical solutions modified in this way do not change the basic concept of the present invention, and thus also fall within the protection scope of the present invention.

[0121] Finally, it should be noted that although this embodiment is described in conjunction with a variable-frequency air conditioner, this is not intended to limit the protection scope of the present application. Those skilled in the art can also apply the present application to other types of air conditioners as long as the air conditioner has an outdoor unit condenser. For example, the present application can also be applied to a fixed-frequency air conditioner, etc.

[0122] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. On the premise of not deviating from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims

1. An outdoor unit condenser, characterized in that, The outdoor unit condenser includes a heat exchange pipe section, a subcooling pipe section, a first regulating valve, a subcooling connecting pipe, and a plurality of subcooling valves. The first end of the subcooling pipe section can be connected to the indoor unit evaporator through a second regulating valve. The first end and the second end of the subcooling pipe section are separated into n subcooling intervals by the plurality of subcooling valves. A plurality of the subcooling intervals are respectively connected to the first end of the first regulating valve through a subcooling connecting pipe. The second end of the first regulating valve is connected to the heat exchange pipe section. The plurality of subcooling valves are configured to be able to adjust the effective length of the subcooling pipe section by controlling the opening and closing of each subcooling valve. The first regulating valve is configured to open a set opening when the heat exchange medium flows from the indoor unit evaporator to the outdoor unit condenser; Among them, the subcooling connecting pipes are provided on the 1st to the n - 1th subcooling intervals starting from the first end of the subcooling pipe section; Among them, the effective length refers to the length of the part of the subcooling pipe section that has a subcooling effect. This length can be controlled by controlling the opening and closing of the subcooling valves. The longest effective length is the full length of the subcooling pipe section.

2. The outdoor unit condenser according to claim 1, characterized in that, The second end of the subcooling pipe section is connected to the heat exchange pipe section. The outdoor unit condenser further includes a confluence connecting pipe and a plurality of confluence valves. A plurality of the subcooling intervals are respectively connected to the second end of the first regulating valve through a confluence connecting pipe. Each confluence connecting pipe is provided with a confluence valve.

3. The outdoor unit condenser according to claim 2, characterized in that, The confluence connecting pipes are provided on the 2nd to the nth subcooling intervals starting from the first end of the subcooling pipe section.

4. The outdoor unit condenser according to claim 1, characterized in that, The outdoor unit condenser further includes a plurality of on-off valves, and each of the plurality of subcooling connecting pipes is provided with an on-off valve.

5. The outdoor unit condenser according to claim 4, characterized in that, The on-off valve is a one-way valve, and the one-way valves are provided on the 2nd to the n - 1th subcooling connecting pipes starting from the first end of the subcooling pipe section; or The on-off valve is a solenoid valve, and the solenoid valves are provided on all the subcooling connecting pipes.

6. The outdoor unit condenser according to claim 1, wherein, The outdoor unit condenser further includes a defrosting temperature detection element provided on the heat exchange pipe section. The defrosting temperature detection element can be connected to a controller so that the controller adjusts the opening and closing of the plurality of subcooling valves based on the temperature collected by the defrosting temperature detection element.

7. The outdoor unit condenser according to claim 1, characterized in that, The outdoor unit condenser further includes a subcooling temperature detection element provided on the subcooling pipe section. The subcooling temperature detection element can be connected to a controller so that the controller adjusts the opening of the first regulating valve based on the temperature collected by the subcooling temperature detection element.

8. The outdoor unit condenser according to claim 1, characterized in that, The subcooling pipe section is provided on the windward side of the outdoor unit condenser; and / or The subcooling pipe section is provided below the heat exchange pipe section.

9. An outdoor unit, characterized in that, The outdoor unit includes the outdoor unit condenser according to any one of claims 1 to 8.

10. A variable frequency air conditioner, characterized in that, The variable frequency air conditioner includes the outdoor unit according to claim 9.

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