Control method of air conditioning equipment and air conditioning equipment

Abstract

The invention relates to the technical field of air conditioning equipment, particularly provides a control method of air conditioning equipment and the air conditioning equipment, and aims to solve the technical problems that the accuracy and the timeliness are poor when the opening degree of a throttle valve is controlled by the existing air conditioning equipment, and the heat exchange efficiency and the operation stability of the air conditioning equipment are influenced. Therefore, the air conditioning equipment comprises an indoor unit heat exchange device, an outdoor unit heat exchange device and a throttling valve, and the control method of the air conditioning equipment comprises the steps that in the refrigeration cycle, the target evaporation pressure of the indoor unit heat exchange device is obtained; the actual condensing pressure of the outdoor unit heat exchange device is obtained; according to the target evaporation pressure, the actual condensation pressure and the preset target dryness, the opening degree of a throttling valve is selectively adjusted, so that the difference value between the actual dryness degree and the target dryness degree of a refrigerant in the indoor unit heat exchange device is not larger than a first preset value, and the refrigerant is adjusted to the ideal dryness degree by controlling the opening degree of the throttling valve. And the heat exchange efficiency and the operation stability of the air conditioning equipment are improved.

Description

Technical Field

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

[0002] The throttle valve is an important refrigeration component on air-conditioning equipment. Its main function is to control the flow rate of refrigerant, and then control the heat exchange efficiency of the heat exchange device. It includes the indoor throttle valve and the outdoor throttle valve. Under refrigeration conditions, the indoor throttle valve adjusts the flow rate of refrigerant by adjusting the opening, which plays the role of throttling and reducing pressure. Its opening directly affects the refrigeration capacity and refrigeration effect of the air-conditioning equipment. Especially in multi-split air-conditioning systems, the control logic of the throttle valve is particularly important. The control accuracy of the throttle valve opening is an important guarantee for achieving high energy efficiency of the multi-split air-conditioning system.

[0003] However, the existing air-conditioning equipment has poor accuracy and timeliness in controlling the opening of the throttle valve, which affects the heat exchange efficiency and operation stability of the air-conditioning equipment.

[0004] Therefore, this field needs a new technical solution to solve the above problems. Summary of the Invention

[0005] The present invention aims to solve the above technical problem, namely, the poor accuracy and timeliness of the existing air-conditioning equipment in controlling the opening of the throttle valve, which affects the heat exchange efficiency and operating stability of the air-conditioning equipment.

[0006] In a first aspect, the present invention provides a control method for air-conditioning equipment, wherein the air-conditioning equipment includes an indoor heat exchange device, an outdoor heat exchange device and a throttle valve, and the control method includes: in a refrigeration cycle, obtaining a target evaporation pressure of the indoor heat exchange device; obtaining an actual condensation pressure of the outdoor heat exchange device; and selectively adjusting the opening of the throttle valve according to the target evaporation pressure, the actual condensation pressure and a preset target dryness, so that the difference between the actual dryness of the refrigerant in the indoor heat exchange device and the target dryness is not greater than a first preset value.

[0007] In the preferred technical solution of the above-mentioned control method, the throttle valve includes an indoor throttle valve and an outdoor throttle valve, and the specific steps of "selectively adjusting the opening of the throttle valve according to the target evaporating pressure, the actual condensing pressure and the preset target dryness so that the difference between the actual dryness of the refrigerant in the indoor heat exchange device and the target dryness is not greater than a first preset value" include: obtaining the target subcooling according to the target dryness, the target evaporating pressure and the actual condensing pressure; obtaining the actual subcooling; selectively adjusting the opening of the outdoor throttle valve according to the target subcooling and the actual subcooling; obtaining the actual evaporating pressure; and selectively adjusting the opening of the indoor throttle valve according to the target evaporating pressure and the actual evaporating pressure.

[0008] In the preferred technical solution of the above-mentioned control method, the specific steps of "obtaining the actual subcooling degree" include: obtaining the actual condensing temperature of the outdoor unit heat exchange device based on the actual condensing pressure; obtaining the valve inlet temperature of the indoor unit throttle valve; calculating the difference between the actual condensing temperature and the valve inlet temperature to obtain the actual subcooling degree.

[0009] In the preferred technical solution of the above-mentioned control method, the specific steps of "selectively adjusting the opening of the external unit throttle valve according to the target subcooling and the actual subcooling" include: calculating the difference between the target subcooling and the actual subcooling, recorded as a first difference; comparing the first difference with a second preset value; if the first difference is greater than the second preset value and the actual subcooling is greater than the target subcooling, increasing the opening of the external unit throttle valve; if the first difference is greater than the second preset value and the actual subcooling is less than the target subcooling, reducing the opening of the external unit throttle valve; if the first difference is not greater than the second preset value, keeping the opening of the external unit throttle valve unchanged.

[0010] In the preferred technical solution of the above-mentioned control method, the specific steps of "selectively adjusting the opening of the external unit throttle valve according to the target subcooling degree and the actual subcooling degree" include: comparing the target subcooling degree with the actual subcooling degree; if the actual subcooling degree is greater than the target subcooling degree, increasing the opening of the external unit throttle valve; if the actual subcooling degree is less than the target subcooling degree, reducing the opening of the external unit throttle valve; if the actual subcooling degree is equal to the target subcooling degree, keeping the opening of the external unit throttle valve unchanged.

[0011] In the preferred technical solution of the above-mentioned control method, the indoor heat exchange device is provided in plurality and arranged in parallel, and each indoor heat exchange device is equipped with an indoor throttle valve. The specific steps of "obtaining the target evaporation pressure of the indoor heat exchange device" include: obtaining the start-up rate of the plurality of indoor heat exchange devices; obtaining the set target temperature; and obtaining the target evaporation pressure based on the start-up rate and the target temperature.

[0012] In the preferred technical solution of the above-mentioned control method, the specific steps of "selectively adjusting the opening of the internal machine throttle valve according to the target evaporation pressure and the actual evaporation pressure" include: calculating the difference between the target evaporation pressure and the actual evaporation pressure, recorded as the second difference; comparing the second difference with a third preset value; if the second difference is greater than the third preset value and the actual evaporation pressure is greater than the target evaporation pressure, increasing the opening of the internal machine throttle valve; if the second difference is greater than the third preset value and the actual evaporation pressure is less than the target evaporation pressure, reducing the opening of the internal machine throttle valve; if the second difference is not greater than the third preset value, keeping the opening of the internal machine throttle valve unchanged.

[0013] In the preferred technical solution of the above-mentioned control method, the specific steps of "selectively adjusting the opening of the internal machine throttle valve according to the target evaporation pressure and the actual evaporation pressure" include: comparing the actual evaporation pressure with the target evaporation pressure; if the actual evaporation pressure is greater than the target evaporation pressure, increasing the opening of the internal machine throttle valve; if the actual evaporation pressure is less than the target evaporation pressure, reducing the opening of the internal machine throttle valve; if the actual evaporation pressure is equal to the target evaporation pressure, keeping the opening of the internal machine throttle valve unchanged.

[0014] In the preferred technical solution of the above control method, the air-conditioning equipment further includes a decreasing exhaust enthalpy-increasing heat exchanger and a decreasing exhaust throttle valve, the inlet of the decreasing exhaust throttle valve is connected to the outlet of the external unit throttle valve, the outlet of the decreasing exhaust throttle valve is connected to the gas path inlet of the decreasing exhaust enthalpy-increasing heat exchanger, the gas path outlet of the decreasing exhaust enthalpy-increasing heat exchanger is connected to the inlet of the gas-liquid separator of the air-conditioning equipment, the liquid path inlet of the decreasing exhaust enthalpy-increasing heat exchanger is connected to the outlet of the external unit throttle valve, and the liquid path of the decreasing exhaust enthalpy-increasing heat exchanger is connected to the outlet of the external unit throttle valve. The outlet is connected to the inlet of the indoor unit throttle valve to reduce the exhaust temperature of the compressor of the air-conditioning equipment. The air-conditioning equipment also includes a regenerative heat exchanger, the gas inlet of the regenerative heat exchanger is connected to the outlet of the gas-liquid separator, the gas outlet of the regenerative heat exchanger is connected to the inlet of the compressor, the liquid inlet of the regenerative heat exchanger is connected to the liquid outlet of the exhaust gas enthalpy reduction and increase heat exchanger, and the liquid outlet of the regenerative heat exchanger is connected to the inlet of the indoor unit throttle valve to increase the intake superheat of the compressor.

[0015] In a second aspect, the present invention provides an air conditioning device, comprising a controller configured to execute the above control method.

[0016] In the case of adopting the above technical solution, the air conditioner of the present invention includes an indoor heat exchange device, an outdoor heat exchange device, and a throttle valve. The control method of the present invention includes: obtaining a target evaporating pressure of the indoor heat exchange device during a refrigeration cycle; obtaining an actual condensing pressure of the outdoor heat exchange device; and selectively adjusting the opening of the throttle valve based on the target evaporating pressure, the actual condensing pressure, and a preset target dryness, so that the difference between the actual dryness of the refrigerant in the indoor heat exchange device and the target dryness is no greater than a first preset value. By such an arrangement, the throttle valve opening is controlled based on the target dryness of the refrigerant, ultimately adjusting the actual dryness of the refrigerant in the indoor heat exchange device to an ideal dryness range. On the one hand, the heat exchange efficiency of the heat exchange device is improved, the heat exchange efficiency of the heat exchange device is maximized, and the performance of the air conditioner is enhanced. On the other hand, in the process of controlling the throttle valve, the shortcomings of conventional methods of controlling the throttle valve opening based on superheat in air conditioners, such as poor accuracy and timeliness, and the tendency to cause valve opening control oscillation, resulting in control imbalance, are overcome, thereby improving the control accuracy and operational stability of the air conditioner.

[0017] Furthermore, the throttle valve of the present invention includes an indoor throttle valve and an outdoor throttle valve, and the control method of the present invention further includes: obtaining a target subcooling degree according to a target dryness, a target evaporation pressure, and an actual condensing pressure; obtaining an actual subcooling degree; selectively adjusting the opening of the outdoor throttle valve according to the target subcooling degree and the actual subcooling degree; obtaining an actual evaporation pressure; selectively adjusting the opening of the indoor throttle valve according to the target evaporation pressure and the actual evaporation pressure. Through such a setting, on the one hand, the throttling and pressure-reducing effect of the indoor throttle valve or the outdoor throttle valve can be utilized when the refrigerant flows in different directions, so that the air-conditioning equipment can achieve a heating mode and a cooling mode; on the other hand, by adjusting the opening of the outdoor throttle valve according to parameters such as the target dryness degree, the subcooling degree can be adjusted to an ideal range first, so that under the ideal dryness, the purpose of adjusting the refrigerant dryness can be achieved by adjusting the indoor throttle valve, thereby maximizing the heat exchange efficiency of the heat exchange device.

[0018] Furthermore, the control method of the present invention further includes: obtaining the actual condensing temperature of the outdoor unit heat exchange device based on the actual condensing pressure; obtaining the inlet temperature of the indoor unit throttle valve; and calculating the difference between the actual condensing temperature and the inlet temperature to obtain the actual subcooling degree. This arrangement effectively obtains the actual subcooling degree of the system, ensuring accuracy and timeliness of the actual subcooling degree.

[0019] Furthermore, the control method of the present invention further includes: calculating the difference between the target subcooling degree and the actual subcooling degree, recorded as a first difference; comparing the first difference with a second preset value; if the first difference is greater than the second preset value and the actual subcooling degree is greater than the target subcooling degree, increasing the opening of the outdoor unit throttle valve; if the first difference is greater than the second preset value and the actual subcooling degree is less than the target subcooling degree, decreasing the opening of the outdoor unit throttle valve; if the first difference is not greater than the second preset value, maintaining the opening of the outdoor unit throttle valve unchanged. Through such an arrangement, the actual subcooling degree of the system can be adjusted to an ideal range, providing relatively ideal conditions for subsequent adjustment of the refrigerant dryness.

[0020] Furthermore, the control method of the present invention further includes comparing the target subcooling degree with the actual subcooling degree; if the actual subcooling degree is greater than the target subcooling degree, increasing the opening of the outdoor unit's throttle valve; if the actual subcooling degree is less than the target subcooling degree, decreasing the opening of the outdoor unit's throttle valve; and if the actual subcooling degree is equal to the target subcooling degree, maintaining the opening of the outdoor unit's throttle valve unchanged. This configuration provides an alternative control logic for adjusting the outdoor unit's throttle valve for air conditioning equipment.

[0021] Furthermore, the present invention comprises multiple indoor heat exchange devices arranged in parallel, each equipped with an indoor throttle valve. The control method further comprises: obtaining an operating rate of the multiple indoor heat exchange devices; obtaining a set target temperature; and obtaining a target evaporation pressure based on the operating rate and the target temperature. This arrangement enables efficient and accurate determination of the target evaporation pressure of the indoor heat exchange devices, thereby providing an accurate basis for determining and adjusting target subcooling and target dryness.

[0022] Furthermore, the control method of the present invention further includes: calculating the difference between the target evaporation pressure and the actual evaporation pressure, recorded as a second difference; comparing the second difference with a third preset value; if the second difference is greater than the third preset value and the actual evaporation pressure is greater than the target evaporation pressure, increasing the opening of the indoor unit throttle valve; if the second difference is greater than the third preset value and the actual evaporation pressure is less than the target evaporation pressure, decreasing the opening of the indoor unit throttle valve; if the second difference is not greater than the third preset value, maintaining the opening of the indoor unit throttle valve unchanged. Through such an arrangement, it is possible to achieve equivalent control of the actual dryness by controlling the actual evaporation pressure, thereby always controlling the actual dryness of the refrigerant within an ideal dryness range and maximizing the heat exchange efficiency of the air-conditioning equipment during operation.

[0023] Furthermore, the control method of the present invention further includes comparing the actual evaporating pressure with the target evaporating pressure; if the actual evaporating pressure is greater than the target evaporating pressure, increasing the opening of the indoor unit's throttle valve; if the actual evaporating pressure is less than the target evaporating pressure, decreasing the opening of the indoor unit's throttle valve; and if the actual evaporating pressure is equal to the target evaporating pressure, maintaining the opening of the indoor unit's throttle valve unchanged. This configuration provides an alternative control logic for adjusting the indoor unit's throttle valve in an air conditioning system.

[0024] Furthermore, the air-conditioning equipment of the present invention also includes an exhaust gas enthalpy-reducing heat exchanger and an exhaust gas throttle valve. The inlet of the exhaust gas throttle valve is connected to the outlet of the external unit throttle valve, the outlet of the exhaust gas throttle valve is connected to the gas path inlet of the exhaust gas enthalpy-reducing heat exchanger, the gas path outlet of the exhaust gas enthalpy-reducing heat exchanger is connected to the inlet of the gas-liquid separator of the air-conditioning equipment, the liquid path inlet of the exhaust gas enthalpy-reducing heat exchanger is connected to the outlet of the external unit throttle valve, and the liquid path outlet of the exhaust gas enthalpy-reducing heat exchanger is connected to the inlet of the internal unit throttle valve to reduce the exhaust temperature of the compressor of the air-conditioning equipment. The air-conditioning equipment also includes a regenerative heat exchanger, the gas path inlet of the regenerative heat exchanger is connected to the outlet of the gas-liquid separator, the gas path outlet of the regenerative heat exchanger is connected to the inlet of the compressor, the liquid path inlet of the regenerative heat exchanger is connected to the liquid path outlet of the exhaust gas enthalpy-reducing heat exchanger, and the liquid path outlet of the regenerative heat exchanger is connected to the inlet of the internal unit throttle valve to increase the intake superheat of the compressor. Through such a setting, the exhaust enthalpy-reducing heat exchanger and the exhaust throttle valve can be used to reduce the intake temperature and exhaust temperature of the compressor; the heat recovery heat exchanger can avoid the liquid hammer of the compressor caused by insufficient outlet superheat of the indoor heat exchange device when the opening of the refrigerant enthalpy control valve is controlled, thereby ensuring that the suction superheat is within a reasonable range on the basis of achieving efficient heat exchange of the indoor heat exchange device, thereby improving the reliability and stability of the system.

[0025] In addition, the air-conditioning equipment further provided by the present invention on the basis of the above-mentioned technical solution adopts the above-mentioned control method, and thus has the technical effects of the above-mentioned control method. Compared with the air-conditioning equipment before the improvement, the air-conditioning equipment of the present invention controls the opening of the outdoor unit heat exchange device and the outdoor unit throttle valve to make the refrigerant reach the ideal dryness, thereby achieving the purpose of improving the heat exchange efficiency and operation stability of the air-conditioning equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0027] Figure 1 is a schematic diagram of the operation of the air-conditioning device of the present invention;

[0028] Figure 2 is a flow chart of a method for controlling an air-conditioning device according to the present invention;

[0029] Figure 3 It is a flow chart of an embodiment of a method for controlling an air-conditioning device according to the present invention.

[0030] List of reference numerals:

[0031] 11. Indoor unit heat exchange device; 12. Indoor unit throttle valve; 21. Outdoor unit heat exchange device; 22. Outdoor unit throttle valve; 23. Exhaust gas enthalpy reduction and increase heat exchanger; 24. Exhaust gas throttle valve; 25. Regenerative heat exchanger; 26. Compressor; 27. Gas-liquid separator; 28. Oil separator. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0033] It should be noted that, in the description of the present invention, terms such as "inside", "outside", "up", "down", "top", and "bottom" indicating directions or positional relationships 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. Therefore, it cannot be understood as a limitation on the present invention.

[0034] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "installed" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0035] Based on the technical problem pointed out in the background art that the accuracy and timeliness of the throttle valve opening control of the existing air-conditioning equipment are poor, which affects the heat exchange efficiency and operational stability of the air-conditioning equipment. To this end, the present invention provides a control method for air-conditioning equipment and air-conditioning equipment, which aims to selectively control and adjust the throttle valve opening according to the target evaporation pressure of the indoor heat exchange device, the actual condensing pressure of the outdoor heat exchange device, and the preset target dryness of the refrigerant in the refrigeration cycle, so that the actual dryness of the refrigerant in the indoor heat exchange device is maintained within the ideal dryness range, thereby improving the heat exchange efficiency of the heat exchange device, exerting its maximum heat exchange efficiency, and improving the overall performance and stability of the air-conditioning equipment.

[0036] Specifically, if Figure 1 and Figure 2 As shown, the air conditioning device of the present invention includes an indoor heat exchange device 11, an outdoor heat exchange device 21 and a throttle valve. The control method of the present invention includes:

[0037] S100: In the refrigeration cycle, obtaining a target evaporation pressure of an indoor heat exchange device;

[0038] S200: Obtaining the actual condensing pressure of the outdoor heat exchange device;

[0039] S300: Selectively adjust the opening of the throttle valve according to the target evaporation pressure, the actual condensing pressure, and the preset target dryness so that the difference between the actual dryness of the refrigerant in the indoor heat exchange device and the target dryness is no more than a first preset value.

[0040] For example, Figure 1 As shown, the air-conditioning equipment includes an indoor unit part installed indoors and an outdoor unit part installed outdoors. In the preferred embodiment of the present case, the indoor unit part includes an indoor heat exchange device 11 and an indoor throttle valve 12, and the outdoor unit part includes an outdoor heat exchange device 21, an outdoor throttle valve 22, a compressor 26, a gas-liquid separator 27 and an oil separator 28, etc. The various devices are connected through pipelines to form a heat exchange circulation system of the air-conditioning equipment. Under the action of the compressor 26, the refrigerant can circulate in the circulation system. By controlling the flow direction of the refrigerant, the cooling or heating of the indoor heat exchange device 11 can be achieved, thereby achieving the purpose of regulating the indoor temperature.

[0041] In the cooling mode, the compressor 26 sucks in low-temperature, low-pressure gaseous refrigerant from the air intake port, and pressurizes it by doing work, turning it into high-temperature, high-pressure gaseous refrigerant and discharging it from the exhaust port. The gaseous refrigerant then passes through the outdoor unit heat exchange device 21, the outdoor unit throttle valve 22, the indoor unit throttle valve 12 and the indoor unit heat exchange device 11 and returns to the compressor 26. During the cycle, compression, condensation, expansion and evaporation are completed, thereby realizing heat exchange.

[0042] The heat exchange efficiency of the heat exchanger is a key factor in determining the performance and overall energy efficiency of the air-conditioning system. An important factor affecting the heat exchange efficiency is the actual dryness of the refrigerant entering the heat exchanger. The existing method of controlling the throttle valve opening based solely on superheat cannot control the actual dryness of the refrigerant in the heat exchanger, and therefore cannot maximize the heat exchange efficiency of the heat exchanger, thereby wasting part of the heat exchange capacity of the heat exchanger and failing to maximize the energy efficiency of the air-conditioning equipment.

[0043] At the same time, during the operation of the air-conditioning equipment, when the load of the indoor heat exchange device 11 changes rapidly, due to the lag in temperature change, the method of relying solely on the indoor temperature sensor to obtain superheat for valve opening control cannot adapt to the rapid change in the indoor load, resulting in a lag in the control of the valve opening, oscillation and imbalance, and causing the valve to be in a state of constant movement.

[0044] Based on the above reasons, the control method of the present invention obtains the target evaporation pressure of the indoor heat exchange device 11 and the actual condensation pressure of the outdoor heat exchange device 21, and presets corresponding target dryness for different refrigerants (at the target dryness, the heat exchange efficiency can be maximized). At present, depending on the type of refrigerant, its target dryness is mostly between 0.3 and 0.4.

[0045] Therefore, in the cooling mode of the air-conditioning equipment, the opening of the throttle valve can be controlled according to the target evaporating pressure, the actual condensing pressure and the target dryness to adjust the actual dryness of the refrigerant so that the actual dryness approaches the target dryness, and finally the difference between the actual dryness and the target dryness is no greater than a first preset value. In this case, the first preset value is preferably set to 0.02, so that the actual dryness is controlled within an ideal range.

[0046] Therefore, by controlling the opening of the throttle valve based on the target dryness, the actual dryness of the refrigerant in the heat exchange device is finally adjusted to and maintained in the ideal dryness range. On the one hand, the heat exchange efficiency of the heat exchange device can be improved, the maximum heat exchange efficiency of the heat exchange device can be exerted, and the performance of the air-conditioning equipment can be improved; on the other hand, in the process of controlling the throttle valve, the control logic of the traditional air-conditioning equipment that controls the throttle valve opening according to the superheat is overcome, which has the defects of poor accuracy and timeliness, easy valve opening control oscillation, and control imbalance; thus, the control accuracy and operation stability of the air-conditioning equipment are improved.

[0047] Preferably, if Figure 1 and Figure 3 As shown, the throttle valve of the present invention includes an indoor throttle valve 12 and an outdoor throttle valve 22. The specific steps of "selectively adjusting the opening of the throttle valve according to the target evaporation pressure, the actual condensing pressure and the preset target dryness so that the difference between the actual dryness of the refrigerant in the indoor heat exchange device 11 and the target dryness is not greater than a first preset value" include:

[0048] S310: Obtaining a target subcooling degree according to the target dryness, target evaporation pressure, and actual condensation pressure;

[0049] S320: Obtaining actual subcooling degree;

[0050] S330: selectively adjusting the opening of the external unit throttle valve according to the target subcooling degree and the actual subcooling degree;

[0051] S340: Obtaining actual evaporation pressure;

[0052] S350: Selectively adjust the opening of the indoor unit throttle valve according to the target evaporation pressure and the actual evaporation pressure.

[0053] Exemplarily, the indoor unit throttle valve 12 is arranged at the inlet of the indoor unit heat exchange device 11, and the outdoor unit throttle valve 22 is arranged at the outlet of the outdoor unit heat exchange device 21. Unlike the traditional air-conditioning equipment in which the outdoor unit throttle valve 22 only participates in throttling and pressure reduction in the heating mode, the control method of the present invention first adjusts the opening of the outdoor unit throttle valve 22 to make the system reach an ideal supercooling degree. After the supercooling degree of the system reaches the ideal range and remains stable, the indoor unit throttle valve 12 is controlled and adjusted, so that the dryness of the refrigerant can be controlled within the ideal range, thereby maximizing the heat exchange efficiency of the heat exchange device.

[0054] Specifically, when the air conditioner starts the cooling mode, the controller reads the target dryness X of the refrigerant pre-stored in the controller. d , X d The value of is related to the type of refrigerant. The present invention pre-stores corresponding target dryness for different types of refrigerants. Preferably, taking the R410A refrigerant used in the present invention as an example, its target dryness X d =0.4,.

[0055] Then according to the target evaporation pressure P m And the actual condensing pressure P d To calculate the target subcooling SL m , for example, to establish SL m 、X d 、P m and P d The functional relationship between SL m =f(X d , P m , P d ), the functional relationship varies with the type of refrigerant, specifically derived from the pressure-enthalpy characteristic curve of the refrigerant. Taking R410A refrigerant as an example, the SL in the present invention m =5X d 3 +0.02P m 3 +0.3P d 3 +0.76X d 2 P m -0.63X d 2 P d +6P m 2 P d +3.1X d P d 2 Among them, the actual condensing pressure P of the outdoor heat exchange device 21 dThe target evaporation pressure P of the indoor heat exchange device 11 can be detected by the pressure sensor installed in the outdoor heat exchange device 21 and transmitted to the controller of the air-conditioning equipment. m The specific method of obtaining is described in detail below.

[0056] In this case, the target subcooling degree obtained according to the above formula and parameters is 3°C to 8°C.

[0057] After obtaining the target subcooling degree, the system will obtain the actual subcooling degree SL in real time. The specific method of obtaining the actual subcooling degree SL is also described in detail below. The system judges the actual subcooling degree SL and the target subcooling degree SL in real time. m The comparative relationship between them is used to control the opening of the outdoor unit throttle valve 22 and to adjust and correct the opening in real time.

[0058] For example, the specific control principle is: if the actual subcooling degree SL is greater than the target subcooling degree SL m , then at this time it is necessary to increase the opening of the outdoor unit throttle valve 22 to reduce the actual subcooling degree SL. If the actual subcooling degree SL is less than the target subcooling degree SL m , then reduce the valve opening until the actual subcooling degree SL is consistent with the target subcooling degree SL m close to or equal to each other, thereby keeping the actual subcooling SL within the ideal range.

[0059] When the actual subcooling degree SL reaches the ideal range and remains stable, the opening of the external unit throttle valve 22 is controlled. At this time, the actual subcooling degree SL is proportional to the actual condensing pressure P d All are in a constant state. According to the formula SL=f(X1,P s , P d ) can get the actual dryness X1 and actual evaporation pressure P s The fixed functional relationship between them can be adjusted according to the target evaporation pressure P m The actual evaporation pressure P s The opening of the internal throttle valve 12 is controlled by comparing the relationship between the actual evaporation pressure P s Less than the target evaporation pressure P m When the opening of the internal machine throttle valve 12 is reduced, the actual evaporation pressure P s Increase; when the actual evaporation pressure P s Greater than the target evaporation pressure P m When the valve opening is increased, the actual evaporation pressure P s When the actual evaporation pressure P s Close to or equal to the target evaporation pressure P m When the actual dryness X1 is close to or equal to the target dryness X dFinally, the opening of the outdoor unit throttle valve 22 is fixed, thereby completing a control process. During the operation in the cooling mode, the system needs to continuously repeat the above control process.

[0060] It should be noted that a certain time interval is required between the execution of two adjacent control processes. The control method of the present invention preferably sets the interval time between two control processes to 5s, 10s or 15s to make the system stable.

[0061] Through such a setting, on the one hand, the throttling and pressure-reducing effect of the indoor throttle valve 12 or the outdoor throttle valve 22 can be utilized when the refrigerant flows in different directions, so that the air-conditioning equipment can realize heating mode or cooling mode; on the other hand, the opening of the outdoor throttle valve 22 is first adjusted according to parameters such as the target dryness, and the supercooling degree can be adjusted to the ideal range first. Finally, the dryness of the refrigerant is adjusted to the most ideal range by adjusting the indoor throttle valve 12, thereby maximizing the heat exchange efficiency of the heat exchange device.

[0062] Preferably, the specific steps of "obtaining the actual subcooling degree" include:

[0063] S321: Obtaining the actual condensing temperature of the outdoor heat exchange device according to the actual condensing pressure;

[0064] S322: Obtaining the temperature before the throttle valve of the indoor unit;

[0065] S323: Calculate the difference between the actual condensing temperature and the temperature before the valve to obtain the actual subcooling degree.

[0066] For example, the actual condensing pressure P is obtained by a pressure sensor installed in the outdoor heat exchange device 21. d Then, by querying the refrigerant temperature and pressure comparison table, the actual condensation temperature T corresponding to the pressure can be obtained. l The temperature sensor is used to obtain the temperature T before the throttle valve 12 of the internal machine. nq , and finally according to T l and T nq , the actual subcooling SL can be calculated, the actual subcooling is the actual condensing temperature T l The temperature T before the throttle valve 12 of the internal machine nq The difference, that is, SL = T l -T nq .

[0067] Through such a setting, the actual supercooling degree of the system can be effectively obtained and the accuracy of the actual supercooling degree can be guaranteed.

[0068] Regarding the opening control of the external unit throttle valve 22 , the present invention provides two preferred implementations.

[0069] In a first preferred embodiment of the present invention, the specific steps of “selectively adjusting the opening of the external unit throttle valve according to the target subcooling degree and the actual subcooling degree” include:

[0070] S331: Calculate the difference between the target subcooling degree and the actual subcooling degree, and record it as a first difference;

[0071] S332: Compare the first difference with a second preset value;

[0072] S333: If the first difference is greater than the second preset value and the actual subcooling degree is greater than the target subcooling degree, increasing the opening of the outdoor unit throttle valve;

[0073] S334: If the first difference is greater than the second preset value and the actual subcooling degree is less than the target subcooling degree, reducing the opening of the outdoor unit throttle valve;

[0074] S335: If the first difference is not greater than the second preset value, the opening of the outdoor unit throttle valve is kept unchanged.

[0075] Among them, the second preset value is preferably set to 0.2.

[0076] Through such a setting, the actual subcooling degree of the system can be adjusted to the ideal range, providing relatively ideal conditions for the subsequent adjustment of the refrigerant dryness.

[0077] In the second preferred real-time mode of the present invention, the specific steps of "selectively adjusting the opening of the external unit throttle valve according to the target subcooling degree and the actual subcooling degree" include:

[0078] S331: comparing the target subcooling degree with the actual subcooling degree;

[0079] S332: If the actual subcooling degree is greater than the target subcooling degree, increase the opening of the outdoor unit throttle valve;

[0080] S333: If the actual subcooling degree is less than the target subcooling degree, reducing the opening of the outdoor unit throttle valve;

[0081] S334: If the actual subcooling degree is equal to the target subcooling degree, the opening degree of the outdoor unit throttle valve is kept unchanged.

[0082] Through such an arrangement, another control logic for adjusting the opening of the indoor throttle valve 12 is provided for the air-conditioning equipment.

[0083] Preferably, if Figure 1 As shown, the present invention includes multiple indoor heat exchange devices 11 arranged in parallel, and each indoor heat exchange device 11 is equipped with an indoor throttle valve 12. The specific steps of "obtaining the target evaporation pressure of the indoor heat exchange device" include:

[0084] S110: Obtaining the operating rates of multiple indoor heat exchange devices;

[0085] S120: Obtaining the set target temperature;

[0086] S130: Obtain a target evaporation pressure according to the startup rate and the target temperature.

[0087] Exemplarily, the air-conditioning device of the present invention is a multi-supply air-conditioning device, which includes a plurality of indoor heat exchange devices 11 arranged in parallel, usually arranged in different rooms. The indoor throttle valve 12 configured on each indoor heat exchange device 11 can independently adjust the temperature of different rooms.

[0088] Target evaporation pressure P m Based on the operating rate K and target temperature T m Decision, that is, P m =f(K, T m ), where the startup rate K is the ratio of the number of started internal heat exchange devices 11 to the total number of internal heat exchange devices 11, and the target temperature T m is the room temperature, which can be set by the user through the air conditioner remote control or by the air conditioner according to the program. m ) is the functional relationship between K and Tm. The specific functional relationship is obtained by curve fitting in the experiment. In this case, P m =0.48K 2 +0.6T m , the target evaporation pressure in this case varies between 4 bar and 15 bar.

[0089] In this way, the target evaporation pressure of the indoor heat exchange device 11 can be accurately and effectively obtained, thereby providing an accurate basis for obtaining and adjusting the target supercooling degree and the target dryness.

[0090] Regarding the opening control of the internal machine throttle valve 12, the present invention also provides two preferred implementations.

[0091] In a first preferred embodiment of the present invention, the specific steps of “selectively adjusting the opening of the indoor unit throttle valve according to the target evaporation pressure and the actual evaporation pressure” include:

[0092] S351: Calculate the difference between the target evaporation pressure and the actual evaporation pressure, and record it as a second difference;

[0093] S352: Compare the second difference with a third preset value;

[0094] S353: If the second difference is greater than the third preset value and the actual evaporation pressure is greater than the target evaporation pressure, increase the opening of the indoor unit throttle valve;

[0095] S354: If the second difference is greater than the third preset value and the actual evaporation pressure is less than the target evaporation pressure, reducing the opening of the indoor unit throttle valve;

[0096] S355: If the second difference is not greater than the third preset value, the opening of the indoor unit throttle valve is kept unchanged.

[0097] Among them, the third preset value is preferably set to 1.

[0098] Through such a setting, the actual dryness can be equivalently controlled by controlling the actual evaporation pressure, so that the actual dryness of the refrigerant is always controlled within the ideal dryness range, thereby maximizing the heat exchange efficiency of the air-conditioning equipment during operation.

[0099] In a second preferred embodiment of the present invention, the specific steps of “selectively adjusting the opening of the indoor unit throttle valve according to the target evaporation pressure and the actual evaporation pressure” include:

[0100] S351: Comparing the actual evaporation pressure with the target evaporation pressure;

[0101] S352: If the actual evaporation pressure is greater than the target evaporation pressure, increase the opening of the indoor unit throttle valve;

[0102] S353: If the actual evaporation pressure is lower than the target evaporation pressure, reduce the opening of the indoor unit throttle valve;

[0103] S354: If the actual evaporation pressure is equal to the target evaporation pressure, the opening of the indoor unit throttle valve is kept unchanged.

[0104] This provides another control logic for adjusting the opening of the outdoor unit throttle valve 22 for the air-conditioning equipment.

[0105] Preferably, if Figure 1As shown, the air conditioning equipment of the present invention further includes an exhaust gas enthalpy-increasing heat exchanger 23 and an exhaust gas throttle valve 24. The inlet of the exhaust gas throttle valve 24 is connected to the outlet of the external unit throttle valve 22. The outlet of the exhaust gas throttle valve 24 is connected to the gas path inlet of the exhaust gas enthalpy-increasing heat exchanger 23. The gas path outlet of the exhaust gas enthalpy-increasing heat exchanger 23 is connected to the inlet of the gas-liquid separator 27 of the air conditioning equipment. The liquid path inlet of the exhaust gas enthalpy-increasing heat exchanger 23 is connected to the outlet of the external unit throttle valve 22. The liquid path outlet of the exhaust gas enthalpy-increasing heat exchanger 23 is connected to the inlet of the gas-liquid separator 27 of the air conditioning equipment. The inlet of the indoor unit throttle valve 12 is connected to reduce the exhaust temperature of the compressor 26 of the air-conditioning equipment. The air-conditioning equipment also includes a regenerative heat exchanger 25. The gas inlet of the regenerative heat exchanger 25 is connected to the outlet of the gas-liquid separator 27, the gas outlet of the regenerative heat exchanger 25 is connected to the inlet of the compressor 26, the liquid inlet of the regenerative heat exchanger 25 is connected to the liquid outlet of the exhaust gas enthalpy reduction and increase heat exchanger 23, and the liquid outlet of the regenerative heat exchanger 25 is connected to the inlet of the indoor unit throttle valve 12 to increase the intake superheat of the compressor 26.

[0106] For example, the high-pressure and medium-temperature liquid refrigerant discharged from the outdoor heat exchange device 21 is divided into two paths before entering the exhaust enthalpy-increasing heat exchanger 23. One path flows to the indoor throttle valve 12 through the liquid path of the exhaust enthalpy-increasing heat exchanger 23, and the other path first passes through the throttling and pressure-reducing effect of the exhaust throttle valve 24 to become a low-temperature and low-pressure gas-liquid two-phase refrigerant. The low-temperature and low-pressure gas-liquid two-phase refrigerant then flows to the gas-liquid separator 27 through the gas path of the exhaust enthalpy-increasing heat exchanger 23. In the exhaust enthalpy-increasing heat exchanger 23, the gas path The low-temperature gas-liquid two-phase refrigerant in the heat exchanger 11 exchanges heat with the high-temperature liquid refrigerant in the liquid circuit, so that the liquid component in the refrigerant is fully evaporated and converted into gas, thereby avoiding liquid hammer caused by the liquid refrigerant entering the compressor 26 and damaging the compressor 26. Finally, the low-temperature gaseous refrigerant is mixed with the medium-temperature gaseous refrigerant discharged from the indoor heat exchange device 11 and enters the gas-liquid separator 27, and finally returns to the compressor 26 to reduce the temperature of the refrigerant, thereby achieving cooling of the intake and exhaust of the compressor 26.

[0107] It should be noted that the exhaust throttle valve 24 can be controlled according to the working conditions of the air-conditioning equipment. When the air-conditioning equipment is in a harsh working condition, the exhaust temperature of the compressor 26 will be very high. At this time, the exhaust throttle valve 24 needs to be opened to protect the compressor 26 by lowering the intake and exhaust temperatures of the compressor 26.

[0108] Similarly, the heat exchanger 25 can exchange heat between the high-temperature liquid refrigerant in the liquid circuit and the low-temperature gas-liquid two-phase refrigerant in the gas circuit, so as to further vaporize the liquid components in the gas-liquid two-phase refrigerant, prevent the liquid components from entering the compressor 26 to cause liquid hammer, and avoid damage to the compressor 26.

[0109] Therefore, the exhaust enthalpy-reducing heat exchanger 23 and the exhaust throttle valve 24 can be used to reduce the intake temperature and exhaust temperature of the compressor 26; the heat recovery heat exchanger 25 can avoid the liquid hammer of the compressor 26 caused by insufficient outlet superheat of the indoor unit heat exchange device 11 when the opening of the refrigerant enthalpy control valve is determined, thereby ensuring that the suction superheat is within a reasonable range while achieving efficient heat exchange in the indoor unit, thereby improving the reliability and stability of the system.

[0110] In addition, the air-conditioning equipment further provided by the present invention on the basis of the above-mentioned technical solution adopts the above-mentioned control method, and thus has the technical effects of the above-mentioned control method. Compared with the air-conditioning equipment before the improvement, the air-conditioning equipment of the present invention controls the outdoor heat exchanger and the opening of the outdoor heat exchanger to make the refrigerant reach the ideal dryness, thereby achieving the purpose of improving the heat exchange efficiency and operation stability of the air-conditioning equipment.

[0111] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A method for controlling an air-conditioning device, characterized in that: The air conditioning device includes an indoor heat exchange device, an outdoor heat exchange device and a throttle valve, and the control method includes: In a refrigeration cycle, obtaining a target evaporation pressure of the indoor heat exchange device; Obtaining the actual condensing pressure of the outdoor heat exchange device; The opening of the throttle valve is selectively adjusted according to the target evaporation pressure, the actual condensing pressure and the preset target dryness so that the difference between the actual dryness of the refrigerant in the indoor heat exchange device and the target dryness is no greater than a first preset value.

2. The control method according to claim 1, characterized in that: The throttle valve includes an indoor unit throttle valve and an outdoor unit throttle valve. The specific steps of "selectively adjusting the opening of the throttle valve based on the target evaporation pressure, the actual condensing pressure, and a preset target dryness so that the difference between the actual dryness of the refrigerant in the indoor unit heat exchange device and the target dryness is no greater than a first preset value" include: Obtaining a target degree of subcooling according to the target dryness, the target evaporation pressure, and the actual condensation pressure; Get the actual subcooling degree; selectively adjusting the opening of the outdoor unit throttle valve according to the target subcooling degree and the actual subcooling degree; Get the actual evaporation pressure; The opening of the indoor unit throttle valve is selectively adjusted according to the target evaporation pressure and the actual evaporation pressure.

3. The control method according to claim 2, characterized in that: The specific steps of "obtaining the actual subcooling degree" include: Obtaining the actual condensing temperature of the outdoor heat exchange device according to the actual condensing pressure; Obtaining the temperature before the throttle valve of the internal unit; The difference between the actual condensing temperature and the pre-valve temperature is calculated to obtain the actual subcooling degree.

4. The control method according to claim 2, characterized in that: The specific steps of “selectively adjusting the opening of the outdoor unit throttle valve according to the target subcooling degree and the actual subcooling degree” include: Calculating a difference between the target subcooling degree and the actual subcooling degree, and recording it as a first difference; comparing the first difference with a second preset value; If the first difference is greater than the second preset value and the actual subcooling degree is greater than the target subcooling degree, increasing the opening of the outdoor unit throttle valve; If the first difference is greater than the second preset value and the actual subcooling degree is less than the target subcooling degree, reducing the opening of the outdoor unit throttle valve; If the first difference is not greater than the second preset value, the opening of the external unit throttle valve is kept unchanged.

5. The control method according to claim 2, characterized in that: The specific steps of “selectively adjusting the opening of the outdoor unit throttle valve according to the target subcooling degree and the actual subcooling degree” include: comparing the target subcooling degree with the actual subcooling degree; If the actual degree of subcooling is greater than the target degree of subcooling, increasing the opening of the outdoor unit throttle valve; If the actual subcooling degree is less than the target subcooling degree, reducing the opening of the outdoor unit throttle valve; If the actual degree of subcooling is equal to the target degree of subcooling, the opening of the outdoor unit throttle valve is kept unchanged.

6. The control method according to claim 2, characterized in that: The internal heat exchange device is provided in plurality and arranged in parallel, and each internal heat exchange device is equipped with an internal throttle valve. The specific steps of "obtaining the target evaporation pressure of the internal heat exchange device" include: Obtaining the operating rates of the plurality of indoor heat exchange devices; Get the set target temperature; The target evaporation pressure is obtained according to the startup rate and the target temperature.

7. The control method according to claim 2, characterized in that: The specific steps of “selectively adjusting the opening of the indoor unit throttle valve according to the target evaporation pressure and the actual evaporation pressure” include: Calculating a difference between the target evaporation pressure and the actual evaporation pressure, and recording the difference as a second difference; comparing the second difference with a third preset value; If the second difference is greater than the third preset value and the actual evaporation pressure is greater than the target evaporation pressure, increasing the opening of the indoor unit throttle valve; If the second difference is greater than the third preset value and the actual evaporation pressure is less than the target evaporation pressure, reducing the opening of the indoor unit throttle valve; If the second difference is not greater than the third preset value, the opening of the indoor throttle valve is kept unchanged.

8. The control method according to claim 2, characterized in that: The specific steps of “selectively adjusting the opening of the indoor unit throttle valve according to the target evaporation pressure and the actual evaporation pressure” include: comparing the actual evaporation pressure with the target evaporation pressure; If the actual evaporation pressure is greater than the target evaporation pressure, increasing the opening of the indoor unit throttle valve; If the actual evaporation pressure is lower than the target evaporation pressure, reducing the opening of the indoor unit throttle valve; If the actual evaporation pressure is equal to the target evaporation pressure, the opening of the indoor unit throttle valve is kept unchanged.

9. The control method according to any one of claims 1 to 8, characterized in that: The air conditioning equipment further includes an exhaust enthalpy-increasing heat exchanger and an exhaust enthalpy-increasing throttle valve, the inlet of the exhaust enthalpy-increasing throttle valve being connected to the outlet of the external unit throttle valve, the outlet of the exhaust enthalpy-increasing throttle valve being connected to the gas path inlet of the exhaust enthalpy-increasing heat exchanger, the gas path outlet of the exhaust enthalpy-increasing heat exchanger being connected to the inlet of the gas-liquid separator of the air conditioning equipment, the liquid path inlet of the exhaust enthalpy-increasing heat exchanger being connected to the outlet of the external unit throttle valve, and the liquid path outlet of the exhaust enthalpy-increasing heat exchanger being connected to the inlet of the internal unit throttle valve, so as to reduce the exhaust temperature of the compressor of the air conditioning equipment. The air-conditioning equipment also includes a regenerative heat exchanger, the gas inlet of the regenerative heat exchanger is connected to the outlet of the gas-liquid separator, the gas outlet of the regenerative heat exchanger is connected to the inlet of the compressor, the liquid inlet of the regenerative heat exchanger is connected to the liquid outlet of the exhaust gas enthalpy reduction and increase heat exchanger, and the liquid outlet of the regenerative heat exchanger is connected to the inlet of the indoor unit throttle valve to increase the intake superheat of the compressor.

10. An air conditioning device, characterized in that: The air conditioning apparatus includes a controller configured to execute the control method according to any one of claims 1 to 9 .

Images