A control method and device of an air conditioning system, the air conditioning system and a storage medium

Abstract

The application discloses a control method and device of an air conditioning system, the air conditioning system and a storage medium, and relates to the technical field of air conditioning systems. The method comprises the following steps: when the air conditioning system is started and runs, the opening degree value of a first electronic expansion valve is set as a first set initial opening degree, the opening degree value of a second electronic expansion valve is set as a second set initial opening degree, and the opening degree value of a third electronic expansion valve is set as a third set initial opening degree; the opening degree value of the second electronic expansion valve is adjusted according to the low-temperature suction gas superheat degree of a compressor and the high-temperature suction gas superheat degree of the compressor; and / or the opening degree value of the third electronic expansion valve is adjusted according to the low-temperature suction gas superheat degree of the compressor and the high-temperature suction gas superheat degree of the compressor; and / or the opening degree value of the first electronic expansion valve is adjusted according to the supercooling degree of an outdoor heat exchanger. According to the scheme, a double-temperature evaporator is arranged in an indoor unit, and the distribution of the refrigerant amount of the double-temperature evaporator is adjusted, so that the refrigerating capacity and energy efficiency of the air conditioning system can be improved.

Description

Technical Field

[0001] This invention belongs to the field of air conditioning system technology, specifically relating to a control method, device, air conditioning system and storage medium for an air conditioning system, and particularly to a refrigerant distribution control method, device, air conditioning system and storage medium for a dual-evaporation temperature refrigeration system. Background Technology

[0002] In the relevant solutions, the air conditioning system (such as a household split air conditioner) has only one evaporator. Because the temperature of the air gradually decreases after passing through the evaporator, the temperature difference between the air and the evaporator gradually decreases, resulting in a decrease in the utilization efficiency of the evaporator.

[0003] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The purpose of this invention is to provide a control method, device, air conditioning system, and storage medium for an air conditioning system, in order to solve the problem that in related solutions, the indoor unit of an air conditioning system (such as a household split air conditioner) has only one evaporator. When the air passes through the indoor unit evaporator for heat exchange, the heat transfer temperature difference decreases, resulting in a decrease in the utilization efficiency of the indoor unit evaporator and affecting the cooling capacity and energy efficiency of the air conditioning system. The invention aims to improve the cooling capacity and energy efficiency of the air conditioning system by setting up a dual-temperature evaporator in the indoor unit and adjusting the distribution of refrigerant in the dual-temperature evaporator.

[0005] This invention provides a control method for an air conditioning system, wherein the air conditioning system has an indoor unit and an outdoor unit; the outdoor unit includes: a compressor, an outdoor heat exchanger, a first four-way valve, a second four-way valve, a first electronic expansion valve, a second electronic expansion valve, and a gas-liquid separator; the compressor has a first cylinder, a second cylinder, and a third cylinder, the exhaust ports of the first cylinder, the second cylinder, and the third cylinder being connected as the compressor's exhaust port; the indoor unit includes: a first indoor heat exchanger, a second indoor heat exchanger, and a third electronic expansion valve; wherein the compressor's exhaust port is connected to the first valve port of the first four-way valve and the third valve port of the second four-way valve, respectively; The second port of the first four-way valve is connected to the second port of the second four-way valve. The second port of the first four-way valve, after passing through the outdoor heat exchanger, the first electronic expansion valve, the gas-liquid separator, and the second electronic expansion valve, splits into two paths: one path passes through the first indoor heat exchanger and connects to the fourth port of the first four-way valve, and the third port of the first four-way valve connects to the intake port of the second cylinder; the other path passes through the third electronic expansion valve and the second indoor heat exchanger and connects to the fourth port of the second four-way valve, and the first port of the second four-way valve connects to the intake port of the first cylinder; the gas outlet of the gas-liquid separator connects to the intake port of the third cylinder; the control of the air conditioning system... The method includes: when the air conditioning system has just started operating after being turned on, controlling the opening value of the first electronic expansion valve to a first preset initial opening value, controlling the opening value of the second electronic expansion valve to a second preset initial opening value, and controlling the opening value of the third electronic expansion valve to a third preset initial opening value; acquiring the refrigerant temperature at the suction port of the first cylinder of the compressor at preset sampling intervals, and recording it as the low-temperature suction temperature of the compressor; acquiring the refrigerant temperature at the suction port of the second cylinder of the compressor, and recording it as the high-temperature suction temperature of the compressor; acquiring the refrigerant temperature at the outlet of the first indoor heat exchanger, and recording it as the outlet temperature of the first indoor heat exchanger; acquiring the refrigerant temperature at the outlet of the second indoor heat exchanger... The temperature is denoted as the outlet temperature of the second indoor heat exchanger; the refrigerant temperature at the middle of the outdoor heat exchanger is denoted as the middle temperature of the outdoor heat exchanger; the refrigerant temperature at the outlet of the outdoor heat exchanger is denoted as the outlet temperature of the outdoor heat exchanger; the difference between the low-temperature suction temperature of the compressor and the outlet temperature of the second indoor heat exchanger is determined as the low-temperature suction superheat of the compressor; the difference between the high-temperature suction temperature of the compressor and the outlet temperature of the first indoor heat exchanger is determined as the high-temperature suction superheat of the compressor; and the difference between the middle temperature of the outdoor heat exchanger and the outlet temperature of the outdoor heat exchanger is determined as the subcooling of the outdoor heat exchanger.The opening value of the second electronic expansion valve is adjusted according to the low-temperature suction superheat and the high-temperature suction superheat of the compressor; and / or, the opening value of the third electronic expansion valve is adjusted according to the low-temperature suction superheat and the high-temperature suction superheat of the compressor; and / or, the opening value of the first electronic expansion valve is adjusted according to the subcooling of the outdoor heat exchanger.

[0006] In some embodiments, adjusting the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor includes: when the high-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to a first set temperature threshold, if the low-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to a second set temperature threshold, or if the low-temperature suction superheat of the compressor is less than 0, controlling the opening value of the second electronic expansion valve to maintain the current opening value of the second electronic expansion valve; when the high-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to the first set temperature threshold, if the low-temperature suction superheat of the compressor is greater than the second set temperature threshold, controlling the opening value of the second electronic expansion valve to increase by a set step based on the current opening value of the second electronic expansion valve.

[0007] In some embodiments, adjusting the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor further includes: if the high-temperature suction superheat of the compressor is greater than a first set temperature threshold, and if the low-temperature suction superheat of the compressor is greater than or equal to 0, then controlling the opening value of the second electronic expansion valve to increase by a set step based on the current opening value of the second electronic expansion valve; if the high-temperature suction superheat of the compressor is greater than the first set temperature threshold, and if the low-temperature suction superheat of the compressor is less than 0, then controlling the opening value of the second electronic expansion valve to maintain the current opening value of the second electronic expansion valve.

[0008] In some embodiments, adjusting the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor further includes: if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then controlling the opening value of the second electronic expansion valve to maintain the current opening value of the second electronic expansion valve; if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is less than 0, then controlling the opening value of the second electronic expansion valve to decrease by a set step based on the current opening value of the second electronic expansion valve.

[0009] In some embodiments, the opening value of the third electronic expansion valve is adjusted according to the low-temperature suction superheat and the high-temperature suction superheat of the compressor, including: if the high-temperature suction superheat of the compressor is greater than or equal to 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then the opening value of the third electronic expansion valve is controlled to maintain the current opening value of the third electronic expansion valve; if the high-temperature suction superheat of the compressor is greater than or equal to 0, and the low-temperature suction superheat of the compressor is less than 0, then the opening value of the third electronic expansion valve is controlled to decrease by a set step based on the current opening value of the third electronic expansion valve.

[0010] In some embodiments, adjusting the opening value of the third electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor further includes: if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then controlling the opening value of the third electronic expansion valve to increase by a set step based on the current opening value of the third electronic expansion valve; if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is less than 0, then controlling the opening value of the third electronic expansion valve to maintain the current opening value of the third electronic expansion valve.

[0011] In some embodiments, adjusting the opening value of the first electronic expansion valve according to the subcooling of the outdoor heat exchanger includes: if the subcooling of the outdoor heat exchanger is greater than a third set temperature threshold, controlling the opening value of the first electronic expansion valve to increase by a set step based on the current opening value of the first electronic expansion valve; if the subcooling of the outdoor heat exchanger is less than a fourth set temperature threshold, controlling the opening value of the first electronic expansion valve to decrease by a set step based on the current opening value of the first electronic expansion valve; if the subcooling of the outdoor heat exchanger is less than or equal to the third set temperature threshold and greater than or equal to the fourth set temperature threshold, controlling the opening value of the first electronic expansion valve to maintain the current opening value of the first electronic expansion valve.

[0012] In conjunction with the above method, another aspect of the present invention provides a control device for an air conditioning system, the air conditioning system having an indoor unit and an outdoor unit; the outdoor unit includes: a compressor, an outdoor heat exchanger, a first four-way valve, a second four-way valve, a first electronic expansion valve, a second electronic expansion valve, and a gas-liquid separator; the compressor has a first cylinder, a second cylinder, and a third cylinder, the exhaust ports of the first cylinder, the second cylinder, and the third cylinder being connected to each other as the exhaust port of the compressor; the indoor unit includes: a first indoor heat exchanger, a second indoor heat exchanger, and a third electronic expansion valve; wherein the exhaust port of the compressor is connected to the first valve port of the first four-way valve and the third valve port of the second four-way valve, respectively; The second valve port of the first four-way valve is connected to the second valve port of the second four-way valve. The second valve port of the first four-way valve, after passing through the outdoor heat exchanger, the first electronic expansion valve, the gas-liquid separator, and the second electronic expansion valve, splits into two paths: one path passes through the first indoor heat exchanger and connects to the fourth valve port of the first four-way valve, and the third valve port of the first four-way valve connects to the intake port of the second cylinder; the other path passes through the third electronic expansion valve and the second indoor heat exchanger and connects to the fourth valve port of the second four-way valve, and the first valve port of the second four-way valve connects to the intake port of the first cylinder; the gas outlet of the gas-liquid separator connects to the intake port of the third cylinder; the control device of the air conditioning system includes: a control unit... The unit is configured to, upon initial operation of the air conditioning system after startup, control the opening value of the first electronic expansion valve to a first preset initial opening value, control the opening value of the second electronic expansion valve to a second preset initial opening value, and control the opening value of the third electronic expansion valve to a third preset initial opening value; the acquisition unit is configured to, at preset sampling intervals, acquire the refrigerant temperature at the suction port of the first cylinder of the compressor, and record it as the low-temperature suction temperature of the compressor; acquire the refrigerant temperature at the suction port of the second cylinder of the compressor, and record it as the high-temperature suction temperature of the compressor; acquire the refrigerant temperature at the outlet of the first indoor heat exchanger, and record it as the outlet temperature of the first indoor heat exchanger; acquire the refrigerant temperature at the outlet of the second indoor heat exchanger. The control unit is further configured to: obtain the refrigerant temperature at the outlet of the second indoor heat exchanger, denoted as the intermediate temperature of the outdoor heat exchanger; obtain the refrigerant temperature at the outlet of the outdoor heat exchanger, denoted as the outlet temperature of the outdoor heat exchanger; determine the difference between the low-temperature suction temperature of the compressor and the outlet temperature of the second indoor heat exchanger as the low-temperature suction superheat of the compressor; determine the difference between the high-temperature suction temperature of the compressor and the outlet temperature of the first indoor heat exchanger as the high-temperature suction superheat of the compressor; and determine the difference between the intermediate temperature of the outdoor heat exchanger and the outlet temperature of the outdoor heat exchanger as the subcooling of the outdoor heat exchanger.The control unit is further configured to adjust the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor; and / or to adjust the opening value of the third electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor; and / or to adjust the opening value of the first electronic expansion valve based on the subcooling of the outdoor heat exchanger.

[0013] In some embodiments, the control unit adjusts the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor, including: when the high-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to a first set temperature threshold, if the low-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to a second set temperature threshold, or if the low-temperature suction superheat of the compressor is less than 0, then controlling the opening value of the second electronic expansion valve to maintain the current opening value of the second electronic expansion valve; when the high-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to the first set temperature threshold, if the low-temperature suction superheat of the compressor is greater than the second set temperature threshold, then controlling the opening value of the second electronic expansion valve to increase by a set step based on the current opening value of the second electronic expansion valve.

[0014] In some embodiments, the control unit adjusts the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor, further comprising: if the high-temperature suction superheat of the compressor is greater than a first set temperature threshold, and if the low-temperature suction superheat of the compressor is greater than or equal to 0, then controlling the opening value of the second electronic expansion valve to increase by a set step based on the current opening value of the second electronic expansion valve; if the high-temperature suction superheat of the compressor is greater than the first set temperature threshold, and if the low-temperature suction superheat of the compressor is less than 0, then controlling the opening value of the second electronic expansion valve to maintain the current opening value of the second electronic expansion valve.

[0015] In some embodiments, the control unit adjusts the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor, further comprising: if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then controlling the opening value of the second electronic expansion valve to maintain the current opening value of the second electronic expansion valve; if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is less than 0, then controlling the opening value of the second electronic expansion valve to decrease by a set step based on the current opening value of the second electronic expansion valve.

[0016] In some embodiments, the control unit adjusts the opening value of the third electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor, including: if the high-temperature suction superheat of the compressor is greater than or equal to 0, and if the low-temperature suction superheat of the compressor is greater than or equal to 0, then controlling the opening value of the third electronic expansion valve to maintain the current opening value of the third electronic expansion valve; if the high-temperature suction superheat of the compressor is greater than or equal to 0, and if the low-temperature suction superheat of the compressor is less than 0, then controlling the opening value of the third electronic expansion valve to decrease by a set step based on the current opening value of the third electronic expansion valve.

[0017] In some embodiments, the control unit adjusts the opening value of the third electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor, further comprising: if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then controlling the opening value of the third electronic expansion valve to increase by a set step based on the current opening value of the third electronic expansion valve; if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is less than 0, then controlling the opening value of the third electronic expansion valve to maintain the current opening value of the third electronic expansion valve.

[0018] In some embodiments, the control unit adjusts the opening value of the first electronic expansion valve according to the subcooling of the outdoor heat exchanger, including: if the subcooling of the outdoor heat exchanger is greater than a third set temperature threshold, controlling the opening value of the first electronic expansion valve to increase by a set step based on the current opening value of the first electronic expansion valve; if the subcooling of the outdoor heat exchanger is less than a fourth set temperature threshold, controlling the opening value of the first electronic expansion valve to decrease by a set step based on the current opening value of the first electronic expansion valve; if the subcooling of the outdoor heat exchanger is less than or equal to the third set temperature threshold and greater than or equal to the fourth set temperature threshold, controlling the opening value of the first electronic expansion valve to maintain the current opening value of the first electronic expansion valve.

[0019] In conjunction with the above-described device, the present invention further provides an air conditioning system, comprising: the control device for the air conditioning system described above.

[0020] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device on which the storage medium is located executes the control method of the air conditioning system described above.

[0021] Therefore, the solution of the present invention, by setting an outdoor heat exchanger, two four-way valves, two electronic expansion valves, and a single-stage compressor with three parallel compressor cylinders in the outdoor unit, and setting two indoor heat exchangers with different evaporation temperatures and one electronic expansion valve in the indoor unit, allows the air to pass through the high-temperature evaporator with a higher evaporation temperature and then through the low-temperature evaporator with a lower evaporation temperature when the air conditioning system is working. The opening of the three electronic expansion valves is controlled according to the subcooling of the outdoor heat exchanger and the superheat of the two indoor heat exchangers to adjust the amount of refrigerant in the two indoor heat exchangers. Thus, by setting a dual-temperature evaporator in the indoor unit and adjusting the distribution of refrigerant in the dual-temperature evaporators, the cooling capacity and energy efficiency of the air conditioning system can be improved.

[0022] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating an embodiment of the control method for an air conditioning system according to the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of a control device for an air conditioning system according to an embodiment of the present invention;

[0026] Figure 3 A schematic diagram of a structure of an embodiment of a dual-evaporation temperature refrigeration system;

[0027] Figure 4 This is a schematic flowchart of an embodiment of a refrigerant distribution control method for a dual-evaporation temperature refrigeration system.

[0028] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0029] 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0031] Considering that in related solutions, the indoor unit of the air conditioning system (such as a household split air conditioner) has only one evaporator, the heat transfer temperature difference decreases when air passes through the indoor unit evaporator, leading to a reduction in the evaporator's utilization efficiency. To improve the cooling capacity and energy efficiency of the air conditioning system, this invention proposes a control method for an air conditioning system, specifically a refrigerant distribution control method for a dual-evaporation temperature refrigeration system. In this dual-evaporation temperature refrigeration system, the evaporator consists of two parts (such as...). Figure 3 The indoor unit features both a high-temperature evaporator and a low-temperature evaporator. Air first passes through the high-temperature evaporator (where the evaporation temperature is high) and then through the low-temperature evaporator (where the evaporation temperature is low), thus improving the utilization efficiency of the indoor unit's evaporator and increasing the cooling capacity and energy efficiency of the air conditioning system. An electronic expansion valve (such as...) is added to the outdoor unit. Figure 3 The electronic expansion valve 2 shown is an example of an electronic expansion valve added to the indoor unit. Figure 3 The electronic expansion valve 3 shown can be used to adjust the amount of refrigerant in the high-temperature evaporator and the low-temperature evaporator to increase the cooling capacity of the air conditioning system.

[0032] According to embodiments of the present invention, a control method for an air conditioning system is provided, such as... Figure 1The diagram shows a flowchart of an embodiment of the method of the present invention. The air conditioning system includes an indoor unit and an outdoor unit; the outdoor unit includes: a compressor, an outdoor heat exchanger, a first four-way valve, a second four-way valve, a first electronic expansion valve, a second electronic expansion valve, and a gas-liquid separator; the compressor has a first cylinder, a second cylinder, and a third cylinder, the exhaust ports of the first cylinder, the second cylinder, and the third cylinder being connected as the compressor's exhaust port; the indoor unit includes: a first indoor heat exchanger (e.g., a high-temperature indoor heat exchanger), a second indoor heat exchanger (e.g., a low-temperature indoor heat exchanger), and a third electronic expansion valve; wherein the compressor's exhaust port is respectively connected to the first valve port of the first four-way valve and the third valve port of the second four-way valve. The first four-way valve is connected to the second four-way valve. The second valve of the first four-way valve is connected to the outdoor heat exchanger, the first electronic expansion valve, the gas-liquid separator, and the second electronic expansion valve, and then splits into two paths: one path is connected to the fourth valve of the first four-way valve after passing through the first indoor heat exchanger, and the third valve of the first four-way valve is connected to the intake port of the second cylinder; the other path is connected to the fourth valve of the second four-way valve after passing through the third electronic expansion valve and the second indoor heat exchanger, and the first valve of the second four-way valve is connected to the intake port of the first cylinder; the gas outlet of the gas-liquid separator is connected to the intake port of the third cylinder.

[0033] Specifically, Figure 3 This is a schematic diagram of one embodiment of a dual-evaporation temperature refrigeration system. Figure 3 As shown, the dual-evaporation temperature refrigeration system has an indoor unit and an outdoor unit. The outdoor unit includes: four-way valve 1, four-way valve 2, a compressor, a condenser, electronic expansion valve 1, electronic expansion valve 2, and a gas-liquid separator. The first four-way valve is as follows... Figure 3 The four-way valve 1 shown, the second four-way valve as follows Figure 3 The four-way valve 2 shown, the first electronic expansion valve as... Figure 3 The electronic expansion valve 1 and the second electronic expansion valve are shown. Figure 3 The electronic expansion valve 2 and the third electronic expansion valve are shown. Figure 3 The electronic expansion valve 3 shown has a first indoor heat exchanger such as a high-temperature evaporator and a second indoor heat exchanger such as a low-temperature evaporator.

[0034] The compressor comprises cylinders 1, 2, and 3. The exhaust ports of cylinders 1, 2, and 3 are connected, serving as the compressor's exhaust ports. In other words, the compressor consists of three parallel compression cylinders. One cylinder (e.g., cylinder 3) is connected to the gas-liquid separator, one cylinder (e.g., cylinder 2) is connected to the high-temperature evaporator outlet, and one cylinder (e.g., cylinder 1) is connected to the low-temperature evaporator outlet. Four-way valves 1 and 2 function similarly, used to reverse the refrigerant flow, switching between cooling and heating modes. The condenser releases heat from the refrigerant, cooling the high-temperature, high-pressure gaseous refrigerant from the compressor. The electronic expansion valve 1 throttles and reduces pressure, while also regulating the refrigerant circulation volume in the air conditioning system. The gas-liquid separator separates the gaseous and liquid refrigerant; the gaseous refrigerant enters the compressor, while the liquid refrigerant passes through the electronic expansion valve 2 and enters the high-temperature and low-temperature evaporators. Electronic expansion valve 2 is used for throttling and pressure reduction, and also regulates the refrigerant circulation volume entering the high-temperature evaporator and the low-temperature evaporator. Electronic expansion valve 3 is used for throttling and pressure reduction, and also regulates the refrigerant circulation volume entering the high-temperature evaporator and the low-temperature evaporator. The high-temperature evaporator allows the refrigerant to absorb heat, cooling the air passing through it; "high-temperature" means its evaporation temperature is higher than that of the low-temperature evaporator. The low-temperature evaporator allows the refrigerant to absorb heat, cooling the air passing through it; "low-temperature" means its evaporation temperature is lower than that of the high-temperature evaporator.

[0035] like Figure 3 As shown, the compressor consists of three compression cylinders (i.e., three cylinders such as cylinder 1, cylinder 2, and cylinder 3) connected in parallel. One cylinder (e.g., cylinder 2) is connected to the outlet of the first evaporator (e.g., a high-temperature evaporator), one cylinder (e.g., cylinder 1) is connected to the outlet of the second evaporator (e.g., a low-temperature evaporator), and one cylinder (e.g., cylinder 3) is connected to the gas-liquid separator. The exhaust ports of the three compression cylinders (e.g., cylinder 1, cylinder 2, and cylinder 3) are connected together. Four-way valve 1 has four ports: one port is connected to the compressor's exhaust port and four-way valve 2, one port is connected to the first evaporator (e.g., a high-temperature evaporator), one port is connected to one compression cylinder of the compressor (e.g., cylinder 2), and one port is connected to the condenser. Four-way valve 2 also has four ports: one port is connected to the compressor's exhaust port and four-way valve 1, one port is connected to the second evaporator (e.g., a low-temperature evaporator), and one port is connected to one compression cylinder of the compressor (e.g., cylinder 1). The refrigerant enters the gas-liquid separator through the electronic expansion valve 1. The gaseous refrigerant enters one cylinder of the compressor (such as cylinder 3), and the liquid refrigerant is divided into two parts through the electronic expansion valve 2. One part enters the first evaporator (such as the high-temperature evaporator) directly, and the other part enters the second evaporator (such as the low-temperature evaporator) through the electronic expansion valve 3.

[0036] Specifically, in Figure 3In the example shown, the compressor's discharge port is connected to the first port of four-way valve 1. The second port of four-way valve 1, after passing through the condenser, electronic expansion valve 1, gas-liquid separator, and electronic expansion valve 2, splits into two paths: one path passes through the high-temperature evaporator and connects to the fourth port of four-way valve 1, while the third port of four-way valve 1 connects to the intake port of cylinder 2; the other path passes through electronic expansion valve 3 and connects to the fourth port of four-way valve 2, while the first port of four-way valve 2 connects to the intake port of cylinder 1. The second port of four-way valve 2 is connected to the second port of four-way valve 1, and the third port of four-way valve 2 is connected to the first port of four-way valve 1. The gas-liquid separator is connected to the intake port of cylinder 3.

[0037] exist Figure 3 In the example shown, a high-temperature intake temperature sensor T1 is installed on the pipe where the intake port of cylinder 2 is located; a low-temperature intake temperature sensor T2 is installed on the pipe where the intake port of cylinder 1 is located; a condenser intermediate temperature sensor T5 is installed in the middle of the condenser coil; a condenser outlet temperature sensor T6 is installed on the pipe where the condenser outlet is located; a high-temperature evaporator temperature sensor T3 is installed at the outlet of the high-temperature evaporator; and a low-temperature evaporator temperature sensor T4 is installed at the outlet of the low-temperature evaporator. The high-temperature evaporator temperature sensor T3 is used to detect the refrigerant temperature at the evaporator outlet or in the middle of the evaporator. The high-temperature intake temperature sensor T1 is used to detect the refrigerant temperature at the intake port. The low-temperature evaporator temperature sensor T4 is used to detect the refrigerant temperature at the evaporator outlet or in the middle of the evaporator. The low-temperature intake temperature sensor T2 is used to detect the refrigerant temperature at the intake port. The refrigerant temperature at the outlet of the high-temperature evaporator is the high-temperature evaporator outlet temperature T3. The refrigerant temperature at the outlet of the low-temperature evaporator is designated as low-temperature evaporator outlet temperature T4. The refrigerant temperature at the suction port of the high-temperature compressor cylinder is designated as high-temperature suction temperature T1. The refrigerant temperature at the suction port of the low-temperature compressor cylinder is designated as low-temperature suction temperature T2. The refrigerant temperature in the middle of the condenser is designated as condenser middle temperature T5. The refrigerant temperature at the condenser outlet is designated as condenser outlet temperature T6.

[0038] In this invention, the indoor unit evaporator consists of two evaporators (a high-temperature evaporator and a low-temperature evaporator). The air first passes through the high-temperature evaporator and then through the low-temperature evaporator. The indoor unit evaporator has two evaporation temperatures. The air first passes through the high-temperature evaporator and then through the low-temperature evaporator, which improves the refrigerant utilization efficiency and can increase the cooling capacity and energy efficiency of the air conditioning system. At the same time, the presence of the low-temperature evaporator can achieve a lower outlet air temperature.

[0039] In the solution of the present invention, such as Figure 1 As shown, the control method of the air conditioning system includes steps S110 to S140.

[0040] In step S110, when the air conditioning system has just started running after being turned on, the opening value of the first electronic expansion valve is controlled to be a first preset initial opening value, the opening value of the second electronic expansion valve is controlled to be a second preset initial opening value, and the opening value of the third electronic expansion valve is controlled to be a third preset initial opening value.

[0041] In step S120, when the air conditioning system operates under a control mode where the opening value of the first electronic expansion valve is a first preset initial opening value, the opening value of the second electronic expansion valve is a second preset initial opening value, and the opening value of the third electronic expansion valve is a third preset initial opening value, the following are recorded at set sampling intervals: the refrigerant temperature at the suction port of the first cylinder of the compressor is acquired and recorded as the low-temperature suction temperature of the compressor; the refrigerant temperature at the suction port of the second cylinder of the compressor is acquired and recorded as the high-temperature suction temperature of the compressor; the refrigerant temperature at the outlet of the first indoor heat exchanger is acquired and recorded as the outlet temperature of the first indoor heat exchanger; the refrigerant temperature at the outlet of the second indoor heat exchanger is acquired and recorded as the outlet temperature of the second indoor heat exchanger; the refrigerant temperature at the middle of the outdoor heat exchanger is acquired and recorded as the middle temperature of the outdoor heat exchanger; and the refrigerant temperature at the outlet of the outdoor heat exchanger is acquired and recorded as the outlet temperature of the outdoor heat exchanger. The first cylinder of the compressor is a low-temperature cylinder, and the second cylinder of the compressor is a high-temperature cylinder. In cooling mode, the outdoor heat exchanger is a condenser, the first indoor heat exchanger is a high-temperature evaporator, and the second indoor heat exchanger is a low-temperature evaporator.

[0042] Specifically, Figure 4 This is a schematic flowchart of an embodiment of a refrigerant distribution control method for a dual-evaporation temperature refrigeration system. Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system includes control logic for electronic expansion valves 1, 2, and 3. Specifically, it includes: Step 1: After the dual-evaporation temperature refrigeration system unit is powered on and started, the opening values ​​of electronic expansion valves 1, 2, and 3 are controlled to their respective initial opening values, and then Step 2 is executed. In Step 1, the opening value of electronic expansion valve 1 is a first set initial opening value S1, the opening value of electronic expansion valve 2 is a second set initial opening value S2, and the opening value of electronic expansion valve 3 is a third set initial opening value S3. Preferably, in the control logic of electronic expansion valves 1, 2, and 3, the opening values ​​of electronic expansion valve 1, 2, and 3 are adjusted simultaneously.

[0043] In step S130, the difference between the low-temperature suction temperature of the compressor and the outlet temperature of the second indoor heat exchanger is determined as the low-temperature suction superheat of the compressor; the difference between the high-temperature suction temperature of the compressor and the outlet temperature of the first indoor heat exchanger is determined as the high-temperature suction superheat of the compressor; and the difference between the intermediate temperature of the outdoor heat exchanger and the outlet temperature of the outdoor heat exchanger is determined as the subcooling of the outdoor heat exchanger.

[0044] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for the dual-evaporation temperature refrigeration system further includes: Step 2, collecting temperature data once every set sampling time, such as three minutes, including: the refrigerant temperature at the high-temperature compressor cylinder suction port (i.e., high-temperature suction temperature T1), the refrigerant temperature at the low-temperature compressor cylinder suction port (i.e., low-temperature suction temperature T2), the refrigerant temperature at the high-temperature evaporator outlet (i.e., high-temperature evaporator outlet temperature T3), the refrigerant temperature at the low-temperature evaporator outlet (i.e., low-temperature evaporator outlet temperature T4), the refrigerant temperature in the middle of the condenser (i.e., condenser middle temperature T5), and the refrigerant temperature at the condenser outlet (i.e., condenser outlet temperature T6); then calculating the subcooling degree ΔT of the condenser. H The compressor's low-temperature suction superheat ΔT L and the high-temperature suction superheat ΔT of the compressor c Then, steps 3, 4, and 5 are executed. Step 3 adjusts the opening value of electronic expansion valve 2, step 4 adjusts the opening value of electronic expansion valve 3, and step 5 adjusts the opening value of electronic expansion valve 1. The subcooling degree ΔT of the condenser... c = Condenser intermediate temperature T5 - Condenser outlet temperature T6. Compressor low-temperature suction superheat ΔT L = Low-temperature suction temperature T2 - Low-temperature evaporator outlet temperature T4. High-temperature suction superheat ΔT of the compressor. H = High-temperature suction temperature T1 - High-temperature evaporator outlet temperature T3.

[0045] In step S140, the opening value of the second electronic expansion valve is adjusted according to the low-temperature suction superheat and the high-temperature suction superheat of the compressor; and / or, the opening value of the third electronic expansion valve is adjusted according to the low-temperature suction superheat and the high-temperature suction superheat of the compressor; and / or, the opening value of the first electronic expansion valve is adjusted according to the subcooling of the outdoor heat exchanger.

[0046] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for the dual-evaporation temperature refrigeration system further includes: Step 3, the control logic for the opening value of the electronic expansion valve 2 is based on Table 1, according to the compressor's high-temperature suction superheat ΔT. Hand the compressor's low-temperature suction superheat ΔT L Determine whether the opening value of electronic expansion valve 2 has been adjusted. If it has been adjusted, the adjustment increment is set to 2 steps B each time.

[0047] Step 4: The control logic for the opening value of electronic expansion valve 3 is shown in Table 2, based on the compressor's high-temperature suction superheat ΔT. H and the compressor's low-temperature suction superheat ΔT L Determine whether the opening value of the electronic expansion valve 3 has been adjusted. If it has been adjusted, the adjustment increment is set to 2 steps (B) each time.

[0048] Step 5: The control logic for the opening value of electronic expansion valve 1 is shown in Table 3, based on the subcooling degree ΔT of the condenser. c Determine whether the opening value of electronic expansion valve 1 has been adjusted. If it has been adjusted, the adjustment increment is set to 2 steps B each time.

[0049] To improve the cooling capacity and energy efficiency of air conditioning systems, this invention provides a refrigerant distribution control method for a dual-evaporation temperature refrigeration system, wherein a dual-evaporation temperature refrigeration system is configured; in the dual-evaporation temperature refrigeration system, the indoor unit evaporator consists of two parts (e.g., Figure 3 The diagram shows a high-temperature evaporator and a low-temperature evaporator. The air first passes through the high-temperature evaporator (where the evaporation temperature is high) and then through the low-temperature evaporator (where the evaporation temperature is low). This increases the heat transfer temperature difference and solves the problem of the heat transfer temperature difference decreasing when the air passes through the indoor unit's evaporator. This improves the utilization efficiency of the indoor unit's evaporator, thereby increasing the cooling capacity and energy efficiency of the indoor unit. Furthermore, an electronic expansion valve (such as...) is added to the outdoor unit. Figure 3 The electronic expansion valve 2 shown is an example of an electronic expansion valve added to the indoor unit. Figure 3 The electronic expansion valve 3 shown can be used to adjust the amount of refrigerant in the high-temperature evaporator and the low-temperature evaporator to increase the cooling capacity of the air conditioning system.

[0050] In some embodiments, step S140, adjusting the opening value of the second electronic expansion valve based on the low-temperature suction superheat of the compressor and the high-temperature suction superheat of the compressor, includes: a first process of adjusting the opening value of the second electronic expansion valve, specifically including any of the following first processes of adjusting the opening value of the second electronic expansion valve.

[0051] The first process for adjusting the opening value of the second electronic expansion valve is as follows: if the high-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to the first set temperature threshold, and if the low-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to the second set temperature threshold, or if the low-temperature suction superheat of the compressor is less than 0, then the opening value of the second electronic expansion valve is controlled to maintain the current opening value of the second electronic expansion valve.

[0052] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the first set temperature threshold a ≥ the high-temperature suction superheat ΔT of the compressor... H ≥0, the second set temperature threshold b ≥ the compressor's low-temperature suction superheat ΔT L ≥0, the opening value of electronic expansion valve 2 remains unchanged. In step 3, when the first set temperature threshold a ≥ the high-temperature suction superheat ΔT of the compressor... H ≥0, Low-temperature suction superheat ΔT of the compressor L <0, the opening value of electronic expansion valve 2 remains unchanged.

[0053] The first process of adjusting the opening value of the second electronic expansion valve is as follows: when the high-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to the first set temperature threshold, if the low-temperature suction superheat of the compressor is greater than the second set temperature threshold, the opening value of the second electronic expansion valve is controlled to be increased by a set step based on the current opening value of the second electronic expansion valve.

[0054] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the first set temperature threshold a ≥ the high-temperature suction superheat ΔT of the compressor... H ≥0, Low-temperature suction superheat ΔT of the compressor L >When the second set temperature threshold b is reached, the opening value of the electronic expansion valve 2 is increased.

[0055] In some embodiments, step S140, which adjusts the opening value of the second electronic expansion valve based on the low-temperature suction superheat of the compressor and the high-temperature suction superheat of the compressor, further includes a second process of adjusting the opening value of the second electronic expansion valve, specifically including any of the following second processes of adjusting the opening value of the second electronic expansion valve.

[0056] The first process for adjusting the opening value of the second electronic expansion valve: when the high-temperature suction superheat of the compressor is greater than the first set temperature threshold, if the low-temperature suction superheat of the compressor is greater than or equal to 0, the opening value of the second electronic expansion valve is controlled to be increased by a set step based on the current opening value of the second electronic expansion valve.

[0057] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the compressor's high-temperature suction superheat ΔT... H > First set temperature threshold a, compressor low-temperature suction superheat ΔT L ≥0, the opening value of electronic expansion valve 2 is increased.

[0058] The second process for adjusting the opening value of the second electronic expansion valve: if the high-temperature suction superheat of the compressor is greater than the first set temperature threshold, and the low-temperature suction superheat of the compressor is less than 0, then the opening value of the second electronic expansion valve is controlled to maintain the current opening value of the second electronic expansion valve.

[0059] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the compressor's high-temperature suction superheat ΔT... H > First set temperature threshold a, compressor low-temperature suction superheat ΔT L <0, the opening value of electronic expansion valve 2 remains unchanged.

[0060] In some embodiments, step S140, which adjusts the opening value of the second electronic expansion valve based on the low-temperature suction superheat of the compressor and the high-temperature suction superheat of the compressor, further includes a third process of adjusting the opening value of the second electronic expansion valve, specifically including any of the following third processes of adjusting the opening value of the second electronic expansion valve.

[0061] The third process of adjusting the opening value of the second electronic expansion valve: if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then the opening value of the second electronic expansion valve is controlled to maintain the current opening value of the second electronic expansion valve.

[0062] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the compressor's high-temperature suction superheat ΔT... H <0, Low-temperature suction superheat of the compressor ΔT L If the value is ≥0, the opening value of the electronic expansion valve 2 remains unchanged.

[0063] The third process for adjusting the opening value of the second electronic expansion valve is as follows: if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is less than 0, then the opening value of the second electronic expansion valve is controlled to be reduced by a set step based on the current opening value of the second electronic expansion valve.

[0064] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the compressor's high-temperature suction superheat ΔT... H <0, Low-temperature suction superheat of the compressor ΔT L <0, the opening value of electronic expansion valve 2 is reduced.

[0065] Table 1: Control Table for Opening Value of Electronic Expansion Valve 2

[0066]

[0067] By adjusting the opening value of the electronic expansion valve 2 in step 3, the total amount of refrigerant flowing into the high-temperature evaporator and the low-temperature evaporator can be controlled through the electronic expansion valve 2.

[0068] In some embodiments, step S140, adjusting the opening value of the third electronic expansion valve based on the low-temperature suction superheat of the compressor and the high-temperature suction superheat of the compressor, includes: a first process of adjusting the opening value of the third electronic expansion valve, specifically including any of the following first processes of adjusting the opening value of the third electronic expansion valve.

[0069] The first process for adjusting the opening value of the third electronic expansion valve is as follows: if the high-temperature suction superheat of the compressor is greater than or equal to 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then the opening value of the third electronic expansion valve is controlled to maintain the current opening value of the third electronic expansion valve.

[0070] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 4, when the fifth set temperature threshold c ≥ the high-temperature suction superheat ΔT of the compressor... H ≥0, Low-temperature suction superheat ΔT of the compressor L ≥0, the opening value of electronic expansion valve 3 remains unchanged. In step 4, when the high-temperature suction superheat ΔT of the compressor... H > Fifth set temperature threshold c, compressor low-temperature suction superheat ΔT L ≥0, the opening value of electronic expansion valve 3 remains unchanged.

[0071] The first process of adjusting the opening value of the third electronic expansion valve is as follows: if the high-temperature suction superheat of the compressor is greater than or equal to 0, and the low-temperature suction superheat of the compressor is less than 0, then the opening value of the third electronic expansion valve is controlled to be reduced by a set step based on the current opening value of the third electronic expansion valve.

[0072] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 4, when the fifth set temperature threshold c ≥ the high-temperature suction superheat ΔT of the compressor... H ≥0, Low-temperature suction superheat ΔT of the compressor L <0, the opening value of electronic expansion valve 3 is reduced. In step 4, when the compressor's high-temperature suction superheat ΔT H > Fifth set temperature threshold c, compressor low-temperature suction superheat ΔT L <0, the opening value of electronic expansion valve 3 is reduced.

[0073] In some embodiments, step S140, which adjusts the opening value of the third electronic expansion valve based on the low-temperature suction superheat of the compressor and the high-temperature suction superheat of the compressor, further includes a second process of adjusting the opening value of the third electronic expansion valve, specifically including any of the following second processes of adjusting the opening value of the third electronic expansion valve.

[0074] The second process of adjusting the opening value of the third electronic expansion valve is as follows: if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then the opening value of the third electronic expansion valve is controlled to be increased by a set step based on the current opening value of the third electronic expansion valve.

[0075] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 4, when the compressor's high-temperature suction superheat ΔT... H <0, Low-temperature suction superheat of the compressor ΔT L ≥0, the opening value of electronic expansion valve 3 is increased.

[0076] The second process for adjusting the opening value of the third electronic expansion valve is as follows: if the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is less than 0, then the opening value of the third electronic expansion valve is controlled to maintain the current opening value of the third electronic expansion valve.

[0077] Specifically, such as Figure 4As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 4, when the compressor's high-temperature suction superheat ΔT... H <0, Low-temperature suction superheat of the compressor ΔT L <0, the opening value of electronic expansion valve 3 remains unchanged.

[0078] Table 2: Control Table for Opening Value of Electronic Expansion Valve 3

[0079]

[0080] If electronic expansion valve 3 is fully open, the amount of refrigerant allocated to the high-temperature evaporator decreases, while the amount allocated to the low-temperature evaporator increases; if electronic expansion valve 3 is partially closed, the amount of refrigerant allocated to the high-temperature evaporator increases, while the amount allocated to the low-temperature evaporator decreases. Here, d represents the sixth set temperature threshold.

[0081] In some embodiments, step S140 involves adjusting the opening value of the first electronic expansion valve based on the subcooling of the outdoor heat exchanger, including any of the following processes for adjusting the opening value of the first electronic expansion valve:

[0082] The first method of adjusting the opening value of the first electronic expansion valve is as follows: if the subcooling of the outdoor heat exchanger is greater than the third set temperature threshold, the opening value of the first electronic expansion valve is controlled to be increased by a set step based on the current opening value of the first electronic expansion valve.

[0083] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 5, when the subcooling degree ΔT of the condenser... c >The third set temperature threshold e increases the opening value of the electronic expansion valve 1.

[0084] The second process for adjusting the opening value of the first electronic expansion valve is as follows: if the subcooling of the outdoor heat exchanger is less than the fourth set temperature threshold, the opening value of the first electronic expansion valve is controlled to be reduced by a set step based on the current opening value of the first electronic expansion valve.

[0085] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 5, when the subcooling degree ΔT of the condenser... c When the fourth set temperature threshold f is less than or equal to the opening value of the electronic expansion valve 1, the opening value of the electronic expansion valve 1 is reduced.

[0086] The third process for adjusting the opening value of the first electronic expansion valve is as follows: if the subcooling of the outdoor heat exchanger is less than or equal to the third set temperature threshold and greater than or equal to the fourth set temperature threshold, then the opening value of the first electronic expansion valve is controlled to maintain the current opening value of the first electronic expansion valve.

[0087] Specifically, such as Figure 4 As shown, the refrigerant distribution control method of the dual-evaporation temperature refrigeration system further includes: in step 5, when the third set temperature threshold e ≥ the subcooling degree ΔTc of the condenser ≥ the fourth set temperature threshold f, the opening value of the electronic expansion valve 1 remains unchanged.

[0088] Table 3: Control Table for Opening Value of Electronic Expansion Valve 1

[0089]

[0090]

[0091] The electronic expansion valve 1 can control the total refrigerant circulation volume of the dual-temperature refrigeration system.

[0092] Where a takes values ​​in the range [1, 3], b takes values ​​in the range [1, 3], c takes values ​​in the range [1, 2], d takes values ​​in the range [1, 2], e takes values ​​in the range [4, 7], and f takes values ​​in the range [1, 3].

[0093] In this invention, the single-stage compressor uses three cylinders in parallel, and the indoor evaporator is a dual evaporator with different evaporation temperatures; both evaporators are used for cooling, with the air first passing through the high-temperature evaporator and then through the low-temperature evaporator to obtain greater cooling capacity and lower outlet air temperature; an electronic expansion valve (e.g., ...) is added to the outdoor unit. Figure 3 The electronic expansion valve 2 shown is an example of an electronic expansion valve added to the indoor unit. Figure 3 The electronic expansion valve 3 shown is used because an electronic expansion valve (such as...) has been added to the indoor unit. Figure 3 The electronic expansion valve 3 shown is used to obtain a lower evaporation temperature, so the two evaporators in the indoor unit (such as...) Figure 3There is a refrigerant distribution problem between the high-temperature evaporator and the low-temperature evaporator shown. For example, one evaporator may receive too much refrigerant and fail to evaporate completely, while the other evaporator may receive too little refrigerant, resulting in some evaporators not participating in phase change heat transfer. Both situations will lead to a decrease in cooling capacity. Therefore, a control logic needs to be designed to more rationally distribute the refrigerant flowing through the high-temperature evaporator and the low-temperature evaporator. The amount of refrigerant in the high-temperature evaporator and the low-temperature evaporator can be adjusted by electronic expansion valve 2 and electronic expansion valve 3 to solve the refrigerant distribution problem between the two evaporators, that is, to solve the refrigerant distribution problem at dual evaporation temperatures, so that the refrigerant distribution in the high-temperature evaporator and the low-temperature evaporator is more uniform, thereby further improving the cooling capacity of the air conditioning system.

[0094] The technical solution of this embodiment involves installing an outdoor heat exchanger, two four-way valves, two electronic expansion valves, and a single-stage compressor with three parallel compressor cylinders in the outdoor unit of the air conditioning system. The indoor unit contains two indoor heat exchangers with different evaporation temperatures and one electronic expansion valve. During operation, the air first passes through a high-temperature evaporator with a higher evaporation temperature, and then through a low-temperature evaporator with a lower evaporation temperature. The opening of the three electronic expansion valves is controlled based on the subcooling of the outdoor heat exchanger and the superheat of the two indoor heat exchangers to adjust the amount of refrigerant in the two indoor heat exchangers. Therefore, by installing dual-temperature evaporators in the indoor unit and adjusting the distribution of refrigerant in the dual-temperature evaporators, the cooling capacity and energy efficiency of the air conditioning system can be improved.

[0095] According to an embodiment of the present invention, a control device for an air conditioning system corresponding to a control method for an air conditioning system is also provided. See also Figure 2The diagram shows a structural schematic of an embodiment of the device of the present invention. The air conditioning system includes an indoor unit and an outdoor unit; the outdoor unit includes: a compressor, an outdoor heat exchanger, a first four-way valve, a second four-way valve, a first electronic expansion valve, a second electronic expansion valve, and a gas-liquid separator; the compressor has a first cylinder, a second cylinder, and a third cylinder, the exhaust ports of the first cylinder, the second cylinder, and the third cylinder being connected as the compressor's exhaust port; the indoor unit includes: a first indoor heat exchanger, a second indoor heat exchanger, and a third electronic expansion valve; wherein the compressor's exhaust port is connected to the first valve port of the first four-way valve and the third valve port of the second four-way valve, respectively; the first four-way valve... The second valve port is connected to the second valve port of the second four-way valve. The second valve port of the first four-way valve is divided into two paths after passing through the outdoor heat exchanger, the first electronic expansion valve, the gas-liquid separator, and the second electronic expansion valve: one path passes through the first indoor heat exchanger and connects to the fourth valve port of the first four-way valve, and the third valve port of the first four-way valve connects to the intake port of the second cylinder; the other path passes through the third electronic expansion valve and the second indoor heat exchanger and connects to the fourth valve port of the second four-way valve, and the first valve port of the second four-way valve connects to the intake port of the first cylinder; the gas outlet of the gas-liquid separator is connected to the intake port of the third cylinder.

[0096] Specifically, Figure 3 This is a schematic diagram of one embodiment of a dual-evaporation temperature refrigeration system. Figure 3 As shown, the dual-evaporation temperature refrigeration system has an indoor unit and an outdoor unit. The outdoor unit contains: a four-way valve 1, a four-way valve 2, a compressor, a condenser, an electronic expansion valve 1, an electronic expansion valve 2, and a gas-liquid separator. The first four-way valve is as follows... Figure 3 The four-way valve 1 shown, the second four-way valve as follows Figure 3 The four-way valve 2 shown, the first electronic expansion valve as follows Figure 3 The electronic expansion valve 1 and the second electronic expansion valve are shown. Figure 3 The electronic expansion valve 2 and the third electronic expansion valve are shown. Figure 3 The electronic expansion valve 3 shown has a first indoor heat exchanger such as a high-temperature evaporator and a second indoor heat exchanger such as a low-temperature evaporator.

[0097] The compressor comprises cylinders 1, 2, and 3. The exhaust ports of cylinders 1, 2, and 3 are connected, serving as the compressor's exhaust ports. In other words, the compressor consists of three parallel compression cylinders. One cylinder (e.g., cylinder 3) is connected to the gas-liquid separator, one cylinder (e.g., cylinder 2) is connected to the high-temperature evaporator outlet, and one cylinder (e.g., cylinder 1) is connected to the low-temperature evaporator outlet. Four-way valves 1 and 2 function similarly, used to reverse the refrigerant flow, switching between cooling and heating modes. The condenser releases heat from the refrigerant, cooling the high-temperature, high-pressure gaseous refrigerant from the compressor. The electronic expansion valve 1 throttles and reduces pressure, while also regulating the refrigerant circulation volume in the air conditioning system. The gas-liquid separator separates the gaseous and liquid refrigerant; the gaseous refrigerant enters the compressor, while the liquid refrigerant passes through the electronic expansion valve 2 and enters the high-temperature and low-temperature evaporators. Electronic expansion valve 2 is used for throttling and pressure reduction, and also regulates the refrigerant circulation volume entering the high-temperature evaporator and the low-temperature evaporator. Electronic expansion valve 3 is used for throttling and pressure reduction, and also regulates the refrigerant circulation volume entering the high-temperature evaporator and the low-temperature evaporator. The high-temperature evaporator allows the refrigerant to absorb heat, cooling the air passing through it; "high-temperature" means its evaporation temperature is higher than that of the low-temperature evaporator. The low-temperature evaporator allows the refrigerant to absorb heat, cooling the air passing through it; "low-temperature" means its evaporation temperature is lower than that of the high-temperature evaporator.

[0098] like Figure 3 As shown, the compressor consists of three compression cylinders (i.e., three cylinders such as cylinder 1, cylinder 2, and cylinder 3) connected in parallel. One cylinder (e.g., cylinder 2) is connected to the outlet of the first evaporator (e.g., a high-temperature evaporator), one cylinder (e.g., cylinder 1) is connected to the outlet of the second evaporator (e.g., a low-temperature evaporator), and one cylinder (e.g., cylinder 3) is connected to the gas-liquid separator. The exhaust ports of the three compression cylinders (e.g., cylinder 1, cylinder 2, and cylinder 3) are connected together. Four-way valve 1 has four ports: one port is connected to the compressor's exhaust port and four-way valve 2, one port is connected to the first evaporator (e.g., a high-temperature evaporator), one port is connected to one compression cylinder of the compressor (e.g., cylinder 2), and one port is connected to the condenser. Four-way valve 2 also has four ports: one port is connected to the compressor's exhaust port and four-way valve 1, one port is connected to the second evaporator (e.g., a low-temperature evaporator), and one port is connected to one compression cylinder of the compressor (e.g., cylinder 1). The refrigerant enters the gas-liquid separator through the electronic expansion valve 1. The gaseous refrigerant enters one cylinder of the compressor (such as cylinder 3), and the liquid refrigerant is divided into two parts through the electronic expansion valve 2. One part enters the first evaporator (such as the high-temperature evaporator) directly, and the other part enters the second evaporator (such as the low-temperature evaporator) through the electronic expansion valve 3.

[0099] Specifically, in Figure 3In the example shown, the compressor's discharge port is connected to the first port of four-way valve 1. The second port of four-way valve 1, after passing through the condenser, electronic expansion valve 1, gas-liquid separator, and electronic expansion valve 2, splits into two paths: one path passes through the high-temperature evaporator and connects to the fourth port of four-way valve 1, while the third port of four-way valve 1 connects to the intake port of cylinder 2; the other path passes through electronic expansion valve 3 and connects to the fourth port of four-way valve 2, while the first port of four-way valve 2 connects to the intake port of cylinder 1. The second port of four-way valve 2 is connected to the second port of four-way valve 1, and the third port of four-way valve 2 is connected to the first port of four-way valve 1. The gas-liquid separator is connected to the intake port of cylinder 3.

[0100] exist Figure 3 In the example shown, a high-temperature intake temperature sensor T1 is installed on the pipe where the intake port of cylinder 2 is located; a low-temperature intake temperature sensor T2 is installed on the pipe where the intake port of cylinder 1 is located; a condenser intermediate temperature sensor T5 is installed in the middle of the condenser coil; a condenser outlet temperature sensor T6 is installed on the pipe where the condenser outlet is located; a high-temperature evaporator temperature sensor T3 is installed at the outlet of the high-temperature evaporator; and a low-temperature evaporator temperature sensor T4 is installed at the outlet of the low-temperature evaporator. The high-temperature evaporator temperature sensor T3 is used to detect the refrigerant temperature at the evaporator outlet or in the middle of the evaporator. The high-temperature intake temperature sensor T1 is used to detect the refrigerant temperature at the intake port. The low-temperature evaporator temperature sensor T4 is used to detect the refrigerant temperature at the evaporator outlet or in the middle of the evaporator. The low-temperature intake temperature sensor T2 is used to detect the refrigerant temperature at the intake port. The refrigerant temperature at the outlet of the high-temperature evaporator is the high-temperature evaporator outlet temperature T3. The refrigerant temperature at the outlet of the low-temperature evaporator is designated as low-temperature evaporator outlet temperature T4. The refrigerant temperature at the suction port of the high-temperature compressor cylinder is designated as high-temperature suction temperature T1. The refrigerant temperature at the suction port of the low-temperature compressor cylinder is designated as low-temperature suction temperature T2. The refrigerant temperature in the middle of the condenser is designated as condenser middle temperature T5. The refrigerant temperature at the condenser outlet is designated as condenser outlet temperature T6.

[0101] In this invention, the indoor unit evaporator consists of two evaporators (a high-temperature evaporator and a low-temperature evaporator). The air first passes through the high-temperature evaporator and then through the low-temperature evaporator. The indoor unit evaporator has two evaporation temperatures. The air first passes through the high-temperature evaporator and then through the low-temperature evaporator, which improves the refrigerant utilization efficiency and can increase the cooling capacity and energy efficiency of the air conditioning system. At the same time, the presence of the low-temperature evaporator can achieve a lower outlet air temperature.

[0102] In the solution of the present invention, such as Figure 2 As shown, the control device of the air conditioning system includes: an acquisition unit 102 and a control unit 104.

[0103] The control unit 104 is configured to, when the air conditioning system is turned on and just starting to operate, control the opening value of the first electronic expansion valve to a first preset initial opening value, control the opening value of the second electronic expansion valve to a second preset initial opening value, and control the opening value of the third electronic expansion valve to a third preset initial opening value. The specific functions and processing of this control unit 104 are described in step S110.

[0104] The acquisition unit 102 is configured to, when the air conditioning system is operating in a control mode where the opening value of the first electronic expansion valve is a first preset initial opening value, the opening value of the second electronic expansion valve is a second preset initial opening value, and the opening value of the third electronic expansion valve is a third preset initial opening value, acquire, at set sampling intervals, the refrigerant temperature at the suction port of the first cylinder of the compressor, and record it as the low-temperature suction temperature of the compressor; acquire the refrigerant temperature at the suction port of the second cylinder of the compressor, and record it as the high-temperature suction temperature of the compressor; acquire the refrigerant temperature at the outlet of the first indoor heat exchanger, and record it as the outlet temperature of the first indoor heat exchanger; acquire the refrigerant temperature at the outlet of the second indoor heat exchanger, and record it as the outlet temperature of the second indoor heat exchanger; acquire the refrigerant temperature at the middle of the outdoor heat exchanger, and record it as the middle temperature of the outdoor heat exchanger; and acquire the refrigerant temperature at the outlet of the outdoor heat exchanger, and record it as the outlet temperature of the outdoor heat exchanger. The specific functions and processing of this acquisition unit 102 are described in step S120. The first cylinder of the compressor is a low-temperature cylinder, and the second cylinder of the compressor is a high-temperature cylinder. In cooling mode, the outdoor heat exchanger is a condenser, the first indoor heat exchanger is a high-temperature evaporator, and the second indoor heat exchanger is a low-temperature evaporator.

[0105] Specifically, Figure 4 This is a schematic flowchart of an embodiment of a refrigerant distribution control method for a dual-evaporation temperature refrigeration system. Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system includes the control logic for electronic expansion valves 1, 2, and 3. Specifically, it includes: Step 1: After the dual-evaporation temperature refrigeration system unit is powered on and started, the opening values ​​of electronic expansion valves 1, 2, and 3 are controlled to their respective initial opening values, and then Step 2 is executed. In Step 1, the opening value of electronic expansion valve 1 is the first set initial opening value S1, the opening value of electronic expansion valve 2 is the second set initial opening value S2, and the opening value of electronic expansion valve 3 is the third set initial opening value S3.

[0106] The control unit 104 is further configured to determine the difference between the low-temperature suction temperature of the compressor and the outlet temperature of the second indoor heat exchanger as the low-temperature suction superheat of the compressor; to determine the difference between the high-temperature suction temperature of the compressor and the outlet temperature of the first indoor heat exchanger as the high-temperature suction superheat of the compressor; and to determine the difference between the intermediate temperature of the outdoor heat exchanger and the outlet temperature of the outdoor heat exchanger as the subcooling of the outdoor heat exchanger. The specific functions and processing of this control unit 104 are further described in step S130.

[0107] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for the dual-evaporation temperature refrigeration system further includes: Step 2, collecting temperature data once every set sampling time, such as three minutes, including: the refrigerant temperature at the high-temperature compressor cylinder suction port (i.e., high-temperature suction temperature T1), the refrigerant temperature at the low-temperature compressor cylinder suction port (i.e., low-temperature suction temperature T2), the refrigerant temperature at the high-temperature evaporator outlet (i.e., high-temperature evaporator outlet temperature T3), the refrigerant temperature at the low-temperature evaporator outlet (i.e., low-temperature evaporator outlet temperature T4), the refrigerant temperature in the middle of the condenser (i.e., condenser middle temperature T5), and the refrigerant temperature at the condenser outlet (i.e., condenser outlet temperature T6); then calculating the subcooling degree ΔT of the condenser. H The compressor's low-temperature suction superheat ΔT L and the high-temperature suction superheat ΔT of the compressor c Then, steps 3, 4, and 5 are executed. Step 3 adjusts the opening value of electronic expansion valve 2, step 4 adjusts the opening value of electronic expansion valve 3, and step 5 adjusts the opening value of electronic expansion valve 1. The subcooling degree ΔT of the condenser... c = Condenser intermediate temperature T5 - Condenser outlet temperature T6. Compressor low-temperature suction superheat ΔT L = Low-temperature suction temperature T2 - Low-temperature evaporator outlet temperature T4. High-temperature suction superheat ΔT of the compressor. H = High-temperature suction temperature T1 - High-temperature evaporator outlet temperature T3.

[0108] The control unit 104 is further configured to adjust the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor; and / or, adjust the opening value of the third electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor; and / or, adjust the opening value of the first electronic expansion valve based on the subcooling of the outdoor heat exchanger. The specific functions and processing of this control unit 104 are further described in step S140.

[0109] Specifically, such as Figure 4As shown, the refrigerant distribution control method for the dual-evaporation temperature refrigeration system further includes: Step 3, the control logic for the opening value of the electronic expansion valve 2 is based on Table 1, according to the high-temperature suction superheat ΔT of the compressor. H and the compressor's low-temperature suction superheat ΔT L Determine whether the opening value of electronic expansion valve 2 has been adjusted. If it has been adjusted, the adjustment increment is set to 2 steps B each time.

[0110] Step 4: The control logic for the opening value of electronic expansion valve 3 is shown in Table 2, based on the compressor's high-temperature suction superheat ΔT. H and the compressor's low-temperature suction superheat ΔT L Determine whether the opening value of the electronic expansion valve 3 has been adjusted. If it has been adjusted, the adjustment increment is set to 2 steps (B) each time.

[0111] Step 5: The control logic for the opening value of electronic expansion valve 1 is shown in Table 3, based on the subcooling degree ΔT of the condenser. c Determine whether the opening value of electronic expansion valve 1 has been adjusted. If it has been adjusted, the adjustment increment is set to 2 steps B each time.

[0112] To improve the cooling capacity and energy efficiency of air conditioning systems, this invention provides a refrigerant distribution control method for a dual-evaporation temperature refrigeration system, wherein a dual-evaporation temperature refrigeration system is configured; in the dual-evaporation temperature refrigeration system, the indoor unit evaporator consists of two parts (e.g., Figure 3 The diagram shows a high-temperature evaporator and a low-temperature evaporator. The air first passes through the high-temperature evaporator (where the evaporation temperature is high) and then through the low-temperature evaporator (where the evaporation temperature is low). This increases the heat transfer temperature difference and solves the problem of the heat transfer temperature difference decreasing when the air passes through the indoor unit's evaporator. This improves the utilization efficiency of the indoor unit's evaporator, thereby increasing the cooling capacity and energy efficiency of the indoor unit. Furthermore, an electronic expansion valve (such as...) is added to the outdoor unit. Figure 3 The electronic expansion valve 2 shown is an example of an electronic expansion valve added to the indoor unit. Figure 3 The electronic expansion valve 3 shown can be used to adjust the amount of refrigerant in the high-temperature evaporator and the low-temperature evaporator to increase the cooling capacity of the air conditioning system.

[0113] In some embodiments, the control unit 104 adjusts the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor. This includes a first process of adjusting the opening value of the second electronic expansion valve, specifically including any of the following:

[0114] The first process for adjusting the opening value of the second electronic expansion valve: The control unit 104 is specifically configured to, when the high-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to a first set temperature threshold, if the low-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to a second set temperature threshold, or if the low-temperature suction superheat of the compressor is less than 0, control the opening value of the second electronic expansion valve to maintain the current opening value of the second electronic expansion valve.

[0115] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the first set temperature threshold a ≥ the high-temperature suction superheat ΔT of the compressor... H ≥0, the second set temperature threshold b ≥ the compressor's low-temperature suction superheat ΔT L ≥0, the opening value of electronic expansion valve 2 remains unchanged. In step 3, when the first set temperature threshold a ≥ the high-temperature suction superheat ΔT of the compressor... H ≥0, Low-temperature suction superheat ΔT of the compressor L <0, the opening value of electronic expansion valve 2 remains unchanged.

[0116] The second process for adjusting the opening value of the second electronic expansion valve: The control unit 104 is specifically configured to, when the high-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to the first set temperature threshold, if the low-temperature suction superheat of the compressor is greater than the second set temperature threshold, control the opening value of the second electronic expansion valve to increase by a set step based on the current opening value of the second electronic expansion valve.

[0117] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the first set temperature threshold a ≥ the high-temperature suction superheat ΔT of the compressor... H ≥0, Low-temperature suction superheat ΔT of the compressor L >When the second set temperature threshold b is reached, the opening value of the electronic expansion valve 2 is increased.

[0118] In some embodiments, the control unit 104 adjusts the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor. This further includes a second process for adjusting the opening value of the second electronic expansion valve, specifically including any of the following:

[0119] The first process for adjusting the opening value of the second electronic expansion valve: The control unit 104 is specifically configured to, when the high-temperature suction superheat of the compressor is greater than the first set temperature threshold, if the low-temperature suction superheat of the compressor is greater than or equal to 0, control the opening value of the second electronic expansion valve to increase by a set step based on the current opening value of the second electronic expansion valve.

[0120] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the compressor's high-temperature suction superheat ΔT... H > First set temperature threshold a, compressor low-temperature suction superheat ΔT L ≥0, the opening value of electronic expansion valve 2 is increased.

[0121] The second process for adjusting the opening value of the second electronic expansion valve: The control unit 104 is specifically configured to maintain the current opening value of the second electronic expansion valve if the low temperature suction superheat of the compressor is less than 0 when the high temperature suction superheat of the compressor is greater than the first set temperature threshold.

[0122] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the compressor's high-temperature suction superheat ΔT... H > First set temperature threshold a, compressor low-temperature suction superheat ΔT L <0, the opening value of electronic expansion valve 2 remains unchanged.

[0123] In some embodiments, the control unit 104 adjusts the opening value of the second electronic expansion valve according to the low-temperature suction superheat of the compressor and the high-temperature suction superheat of the compressor, and further includes a third process of adjusting the opening value of the second electronic expansion valve, specifically including any of the following third processes of adjusting the opening value of the second electronic expansion valve.

[0124] The third process of adjusting the opening value of the second electronic expansion valve: The control unit 104 is specifically configured to maintain the current opening value of the second electronic expansion valve if the low temperature suction superheat of the compressor is greater than or equal to 0 when the high temperature suction superheat of the compressor is less than 0.

[0125] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the compressor's high-temperature suction superheat ΔT... H<0, Low-temperature suction superheat of the compressor ΔT L If the value is ≥0, the opening value of the electronic expansion valve 2 remains unchanged.

[0126] The third process for adjusting the opening value of the second electronic expansion valve: The control unit 104 is specifically configured to, when the high-temperature suction superheat of the compressor is less than 0, if the low-temperature suction superheat of the compressor is less than 0, control the opening value of the second electronic expansion valve to be reduced by a set step based on the current opening value of the second electronic expansion valve.

[0127] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 3, when the compressor's high-temperature suction superheat ΔT... H <0, Low-temperature suction superheat of the compressor ΔT L <0, the opening value of electronic expansion valve 2 is reduced.

[0128] Table 1: Control Table for Opening Value of Electronic Expansion Valve 2

[0129]

[0130] By adjusting the opening value of the electronic expansion valve 2 in step 3, the total amount of refrigerant flowing into the high-temperature evaporator and the low-temperature evaporator can be controlled through the electronic expansion valve 2.

[0131] In some embodiments, the control unit 104 adjusts the opening value of the third electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor. This includes a first process of adjusting the opening value of the third electronic expansion valve, specifically including any of the following:

[0132] The first process for adjusting the opening value of the third electronic expansion valve: The control unit 104 is specifically configured to, when the high-temperature suction superheat of the compressor is greater than or equal to 0, if the low-temperature suction superheat of the compressor is greater than or equal to 0, control the opening value of the third electronic expansion valve to maintain the current opening value of the third electronic expansion valve.

[0133] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 4, when the fifth set temperature threshold c ≥ the high-temperature suction superheat ΔT of the compressor... H ≥0, Low-temperature suction superheat ΔT of the compressor L ≥0, the opening value of electronic expansion valve 3 remains unchanged. In step 4, when the high-temperature suction superheat ΔT of the compressor...H > Fifth set temperature threshold c, compressor low-temperature suction superheat ΔT L ≥0, the opening value of electronic expansion valve 3 remains unchanged.

[0134] The second process for adjusting the opening value of the third electronic expansion valve is as follows: The control unit 104 is specifically configured to, when the high-temperature suction superheat of the compressor is greater than or equal to 0, if the low-temperature suction superheat of the compressor is less than 0, control the opening value of the third electronic expansion valve to be reduced by a set step based on the current opening value of the third electronic expansion valve.

[0135] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 4, when the fifth set temperature threshold c ≥ the high-temperature suction superheat ΔT of the compressor... H ≥0, Low-temperature suction superheat ΔT of the compressor L <0, the opening value of electronic expansion valve 3 is reduced. In step 4, when the compressor's high-temperature suction superheat ΔT H > Fifth set temperature threshold c, compressor low-temperature suction superheat ΔT L <0, the opening value of electronic expansion valve 3 is reduced.

[0136] In some embodiments, the control unit 104 adjusts the opening value of the third electronic expansion valve according to the low-temperature suction superheat of the compressor and the high-temperature suction superheat of the compressor, and further includes a second process of adjusting the opening value of the third electronic expansion valve, specifically including any of the following second processes of adjusting the opening value of the third electronic expansion valve.

[0137] The first second process for adjusting the opening value of the third electronic expansion valve: The control unit 104 is specifically configured to, when the high-temperature suction superheat of the compressor is less than 0, if the low-temperature suction superheat of the compressor is greater than or equal to 0, control the opening value of the third electronic expansion valve to increase by a set step based on the current opening value of the third electronic expansion valve.

[0138] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 4, when the compressor's high-temperature suction superheat ΔT... H <0, Low-temperature suction superheat of the compressor ΔT L ≥0, the opening value of electronic expansion valve 3 is increased.

[0139] The second process for adjusting the opening value of the third electronic expansion valve: The control unit 104 is specifically configured to, when the high-temperature suction superheat of the compressor is less than 0, if the low-temperature suction superheat of the compressor is less than 0, control the opening value of the third electronic expansion valve to maintain the current opening value of the third electronic expansion valve.

[0140] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 4, when the compressor's high-temperature suction superheat ΔT... H <0, Low-temperature suction superheat of the compressor ΔT L <0, the opening value of electronic expansion valve 3 remains unchanged.

[0141] Table 2: Control Table for Opening Value of Electronic Expansion Valve 3

[0142]

[0143] If electronic expansion valve 3 is fully open, the amount of refrigerant allocated to the high-temperature evaporator decreases, while the amount allocated to the low-temperature evaporator increases; if electronic expansion valve 3 is partially closed, the amount of refrigerant allocated to the high-temperature evaporator increases, while the amount allocated to the low-temperature evaporator decreases. Here, d represents the sixth set temperature threshold.

[0144] In some embodiments, the control unit 104 adjusts the opening value of the first electronic expansion valve according to the subcooling degree of the outdoor heat exchanger, including any of the following processes for adjusting the opening value of the first electronic expansion valve:

[0145] The first process of adjusting the opening value of the first electronic expansion valve: The control unit 104 is specifically configured to, if the subcooling degree of the outdoor heat exchanger is greater than the third set temperature threshold, control the opening value of the first electronic expansion valve to be increased by a set step based on the current opening value of the first electronic expansion valve.

[0146] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 5, when the subcooling degree ΔT of the condenser... c >The third set temperature threshold e increases the opening value of the electronic expansion valve 1.

[0147] The second process for adjusting the opening value of the first electronic expansion valve is as follows: The control unit 104 is further configured to control the opening value of the first electronic expansion valve to be reduced by a set step based on the current opening value of the first electronic expansion valve if the subcooling degree of the outdoor heat exchanger is less than the fourth set temperature threshold.

[0148] Specifically, such as Figure 4 As shown, the refrigerant distribution control method for a dual-evaporation temperature refrigeration system further includes: in step 5, when the subcooling degree ΔT of the condenser... c When the fourth set temperature threshold f is less than or equal to the opening value of the electronic expansion valve 1, the opening value of the electronic expansion valve 1 is reduced.

[0149] The third process for adjusting the opening value of the first electronic expansion valve: The control unit 104 is specifically configured to maintain the current opening value of the first electronic expansion valve if the subcooling of the outdoor heat exchanger is less than or equal to a third set temperature threshold and greater than or equal to a fourth set temperature threshold.

[0150] Specifically, such as Figure 4 As shown, the refrigerant distribution control method of the dual-evaporation temperature refrigeration system further includes: in step 5, when the third set temperature threshold e ≥ the subcooling degree ΔTc of the condenser ≥ the fourth set temperature threshold f, the opening value of the electronic expansion valve 1 remains unchanged.

[0151] Table 3: Control Table for Opening Value of Electronic Expansion Valve 1

[0152]

[0153] The electronic expansion valve 1 can control the total refrigerant circulation volume of the dual-temperature refrigeration system.

[0154] Where a takes values ​​in the range [1, 3], b takes values ​​in the range [1, 3], c takes values ​​in the range [1, 2], d takes values ​​in the range [1, 2], e takes values ​​in the range [4, 7], and f takes values ​​in the range [1, 3].

[0155] In this invention, the single-stage compressor uses three cylinders in parallel, and the indoor evaporator is a dual evaporator with different evaporation temperatures; both evaporators are used for cooling, with the air first passing through the high-temperature evaporator and then through the low-temperature evaporator to obtain greater cooling capacity and lower outlet air temperature; an electronic expansion valve (e.g., ...) is added to the outdoor unit. Figure 3 The electronic expansion valve 2 shown is an example of an electronic expansion valve added to the indoor unit. Figure 3 The electronic expansion valve 3 shown is used because an electronic expansion valve (such as...) has been added to the indoor unit. Figure 3 The electronic expansion valve 3 shown is used to obtain a lower evaporation temperature, so the two evaporators in the indoor unit (such as...) Figure 3There is a refrigerant distribution problem between the high-temperature evaporator and the low-temperature evaporator shown. For example, one evaporator may receive too much refrigerant and fail to evaporate completely, while the other evaporator may receive too little refrigerant, resulting in some evaporators not participating in phase change heat transfer. Both situations will lead to a decrease in cooling capacity. Therefore, a control logic needs to be designed to more rationally distribute the refrigerant flowing through the high-temperature evaporator and the low-temperature evaporator. The amount of refrigerant in the high-temperature evaporator and the low-temperature evaporator can be adjusted by electronic expansion valve 2 and electronic expansion valve 3 to solve the refrigerant distribution problem between the two evaporators, that is, to solve the refrigerant distribution problem at dual evaporation temperatures, so that the refrigerant distribution in the high-temperature evaporator and the low-temperature evaporator is more uniform, thereby further improving the cooling capacity of the air conditioning system.

[0156] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0157] By employing the technical solution of this invention, the indoor and outdoor units of the air conditioning system are configured with an outdoor heat exchanger, two four-way valves, two electronic expansion valves, and a single-stage compressor with three parallel compressor cylinders in the outdoor unit. The indoor unit contains two indoor heat exchangers with different evaporation temperatures and one electronic expansion valve. During operation, the air first passes through a high-temperature evaporator with a higher evaporation temperature, and then through a low-temperature evaporator with a lower evaporation temperature. The opening of the three electronic expansion valves is controlled based on the subcooling of the outdoor heat exchanger and the superheat of the two indoor heat exchangers to adjust the amount of refrigerant in the two indoor heat exchangers. This improves the utilization efficiency of the indoor unit evaporator and enhances the cooling capacity and energy efficiency of the indoor unit.

[0158] According to an embodiment of the present invention, an air conditioning system corresponding to a control device for an air conditioning system is also provided. This air conditioning system may include the control device for the air conditioning system described above.

[0159] Since the processing and functions implemented by the air conditioning system in this embodiment are basically the same as those of the aforementioned device embodiments, principles and examples, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0160] The technical solution of this invention addresses the indoor and outdoor units of an air conditioning system. The outdoor unit includes an outdoor heat exchanger, two four-way valves, two electronic expansion valves, and a single-stage compressor with three parallel compressor cylinders. The indoor unit contains two indoor heat exchangers with different evaporation temperatures and one electronic expansion valve. During operation, air first passes through a high-temperature evaporator (high evaporation temperature) and then through a low-temperature evaporator (low evaporation temperature). The opening of the three electronic expansion valves is controlled based on the subcooling of the outdoor heat exchanger and the superheat of the two indoor heat exchangers to regulate the amount of refrigerant in the two indoor heat exchangers. This results in a more uniform distribution of refrigerant between the high-temperature and low-temperature evaporators, thereby increasing the cooling capacity of the air conditioning system.

[0161] According to an embodiment of the present invention, a storage medium corresponding to a control method for an air conditioning system is also provided. The storage medium includes a stored program, wherein the program controls the device where the storage medium is located to execute the control method for the air conditioning system described above when it is executed.

[0162] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0163] By employing the technical solution of this invention, the indoor and outdoor units of the air conditioning system are configured with an outdoor heat exchanger, two four-way valves, two electronic expansion valves, and a single-stage compressor with three parallel compressor cylinders in the outdoor unit. The indoor unit contains two indoor heat exchangers with different evaporation temperatures and one electronic expansion valve. During operation, the air first passes through a high-temperature evaporator with a higher evaporation temperature, and then through a low-temperature evaporator with a lower evaporation temperature. The opening of the three electronic expansion valves is controlled based on the subcooling of the outdoor heat exchanger and the superheat of the two indoor heat exchangers to adjust the amount of refrigerant in the two indoor heat exchangers. This avoids a decrease in heat transfer temperature as the air passes through the indoor unit evaporator, thereby increasing the cooling capacity of the air conditioning system.

[0164] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0165] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A control method for an air conditioning system, characterized in that, The air conditioning system includes an indoor unit and an outdoor unit. The outdoor unit includes a compressor, an outdoor heat exchanger, a first four-way valve, a second four-way valve, a first electronic expansion valve, a second electronic expansion valve, and a gas-liquid separator. The compressor has a first cylinder, a second cylinder, and a third cylinder, with the exhaust ports of the first, second, and third cylinders connected as the compressor's exhaust ports. The indoor unit includes a first indoor heat exchanger, a second indoor heat exchanger, and a third electronic expansion valve. The compressor's exhaust port is connected to the first port of the first four-way valve and the third port of the second four-way valve, respectively. The second port of the first four-way valve is connected to... The second valve port of the second four-way valve is connected to the first four-way valve. The second valve port of the first four-way valve, after passing through the outdoor heat exchanger, the first electronic expansion valve, the gas-liquid separator, and the second electronic expansion valve, splits into two paths: one path passes through the first indoor heat exchanger and connects to the fourth valve port of the first four-way valve, and the third valve port of the first four-way valve connects to the intake port of the second cylinder; the other path passes through the third electronic expansion valve and the second indoor heat exchanger and connects to the fourth valve port of the second four-way valve, and the first valve port of the second four-way valve connects to the intake port of the first cylinder; the gas outlet of the gas-liquid separator is connected to the intake port of the third cylinder; the control method of the air conditioning system includes: When the air conditioning system has just started running after being turned on, the opening value of the first electronic expansion valve is controlled to be a first preset initial opening value, the opening value of the second electronic expansion valve is controlled to be a second preset initial opening value, and the opening value of the third electronic expansion valve is controlled to be a third preset initial opening value. At set sampling intervals, the refrigerant temperature at the suction port of the first cylinder of the compressor is acquired and recorded as the low-temperature suction temperature of the compressor; the refrigerant temperature at the suction port of the second cylinder of the compressor is acquired and recorded as the high-temperature suction temperature of the compressor; the refrigerant temperature at the outlet of the first indoor heat exchanger is acquired and recorded as the outlet temperature of the first indoor heat exchanger; the refrigerant temperature at the outlet of the second indoor heat exchanger is acquired and recorded as the outlet temperature of the second indoor heat exchanger; the refrigerant temperature at the middle of the outdoor heat exchanger is acquired and recorded as the middle temperature of the outdoor heat exchanger; and the refrigerant temperature at the outlet of the outdoor heat exchanger is acquired and recorded as the outlet temperature of the outdoor heat exchanger. The difference between the low-temperature suction temperature of the compressor and the outlet temperature of the second indoor heat exchanger is determined as the low-temperature suction superheat of the compressor; the difference between the high-temperature suction temperature of the compressor and the outlet temperature of the first indoor heat exchanger is determined as the high-temperature suction superheat of the compressor; and the difference between the intermediate temperature of the outdoor heat exchanger and the outlet temperature of the outdoor heat exchanger is determined as the subcooling of the outdoor heat exchanger. The opening value of the second electronic expansion valve is adjusted according to the low-temperature suction superheat and the high-temperature suction superheat of the compressor; the opening value of the third electronic expansion valve is adjusted according to the low-temperature suction superheat and the high-temperature suction superheat of the compressor; the opening value of the first electronic expansion valve is adjusted according to the subcooling of the outdoor heat exchanger, so as to regulate the amount of refrigerant in the two indoor heat exchangers.

2. The control method for the air conditioning system according to claim 1, characterized in that, The opening value of the second electronic expansion valve is adjusted according to the low-temperature suction superheat and the high-temperature suction superheat of the compressor, including: If the high-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to the first set temperature threshold, and if the low-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to the second set temperature threshold, or if the low-temperature suction superheat of the compressor is less than 0, then the opening value of the second electronic expansion valve is controlled to maintain the current opening value of the second electronic expansion valve. If the high-temperature suction superheat of the compressor is greater than or equal to 0 and less than or equal to the first set temperature threshold, and the low-temperature suction superheat of the compressor is greater than the second set temperature threshold, then the opening value of the second electronic expansion valve is controlled to be increased by a set step based on the current opening value of the second electronic expansion valve.

3. The control method for the air conditioning system according to claim 1, characterized in that, Adjusting the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor, further includes: If the high-temperature suction superheat of the compressor is greater than the first set temperature threshold, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then the opening value of the second electronic expansion valve is controlled to be increased by a set step based on the current opening value of the second electronic expansion valve. If the high-temperature suction superheat of the compressor is greater than the first set temperature threshold, and the low-temperature suction superheat of the compressor is less than 0, then the opening value of the second electronic expansion valve is controlled to maintain the current opening value of the second electronic expansion valve.

4. The control method for an air conditioning system according to any one of claims 1 to 3, characterized in that, Adjusting the opening value of the second electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor, further includes: If the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then the opening value of the second electronic expansion valve is controlled to maintain the current opening value of the second electronic expansion valve. If the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is less than 0, then the opening value of the second electronic expansion valve is controlled to be reduced by a set step based on the current opening value of the second electronic expansion valve.

5. The control method for an air conditioning system according to claim 1, characterized in that, The opening value of the third electronic expansion valve is adjusted based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor, including: If the high-temperature suction superheat of the compressor is greater than or equal to 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then the opening value of the third electronic expansion valve is controlled to maintain the current opening value of the third electronic expansion valve. If the high-temperature suction superheat of the compressor is greater than or equal to 0, and the low-temperature suction superheat of the compressor is less than 0, then the opening value of the third electronic expansion valve is controlled to be reduced by a set step based on the current opening value of the third electronic expansion valve.

6. The control method for an air conditioning system according to claim 1 or 5, characterized in that, Adjusting the opening value of the third electronic expansion valve based on the low-temperature suction superheat and the high-temperature suction superheat of the compressor, further includes: If the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is greater than or equal to 0, then the opening value of the third electronic expansion valve is controlled to be increased by a set step based on the current opening value of the third electronic expansion valve. If the high-temperature suction superheat of the compressor is less than 0, and the low-temperature suction superheat of the compressor is less than 0, then the opening value of the third electronic expansion valve is controlled to maintain the current opening value of the third electronic expansion valve.

7. The control method for an air conditioning system according to claim 1, characterized in that, The opening value of the first electronic expansion valve is adjusted according to the subcooling degree of the outdoor heat exchanger, including: If the subcooling of the outdoor heat exchanger is greater than the third set temperature threshold, the opening value of the first electronic expansion valve is controlled to be increased by a set step based on the current opening value of the first electronic expansion valve. If the subcooling of the outdoor heat exchanger is less than the fourth set temperature threshold, the opening value of the first electronic expansion valve is controlled to be reduced by a set step based on the current opening value of the first electronic expansion valve. If the subcooling of the outdoor heat exchanger is less than or equal to the third set temperature threshold and greater than or equal to the fourth set temperature threshold, then the opening value of the first electronic expansion valve is controlled to maintain the current opening value of the first electronic expansion valve.

8. A control device for an air conditioning system that uses the control method of any one of claims 1 to 7 to achieve control of the air conditioning system, characterized in that, The air conditioning system includes an indoor unit and an outdoor unit. The outdoor unit includes a compressor, an outdoor heat exchanger, a first four-way valve, a second four-way valve, a first electronic expansion valve, a second electronic expansion valve, and a gas-liquid separator. The compressor has a first cylinder, a second cylinder, and a third cylinder, with the exhaust ports of the first, second, and third cylinders connected as the compressor's exhaust ports. The indoor unit includes a first indoor heat exchanger, a second indoor heat exchanger, and a third electronic expansion valve. The compressor's exhaust port is connected to the first port of the first four-way valve and the third port of the second four-way valve, respectively. The second port of the first four-way valve is connected to... The second valve port of the second four-way valve is connected to the first four-way valve. The second valve port of the first four-way valve, after passing through the outdoor heat exchanger, the first electronic expansion valve, the gas-liquid separator, and the second electronic expansion valve, splits into two paths: one path passes through the first indoor heat exchanger and connects to the fourth valve port of the first four-way valve, and the third valve port of the first four-way valve connects to the intake port of the second cylinder; the other path passes through the third electronic expansion valve and the second indoor heat exchanger and connects to the fourth valve port of the second four-way valve, and the first valve port of the second four-way valve connects to the intake port of the first cylinder; the gas outlet of the gas-liquid separator is connected to the intake port of the third cylinder; the control device of the air conditioning system includes: The control unit is configured to, when the air conditioning system has just started operating after being turned on, control the opening value of the first electronic expansion valve to a first preset initial opening value, control the opening value of the second electronic expansion valve to a second preset initial opening value, and control the opening value of the third electronic expansion valve to a third preset initial opening value. The acquisition unit is configured to acquire, at set sampling intervals, the refrigerant temperature at the suction port of the first cylinder of the compressor, and record it as the low-temperature suction temperature of the compressor; acquire the refrigerant temperature at the suction port of the second cylinder of the compressor, and record it as the high-temperature suction temperature of the compressor; acquire the refrigerant temperature at the outlet of the first indoor heat exchanger, and record it as the outlet temperature of the first indoor heat exchanger; acquire the refrigerant temperature at the outlet of the second indoor heat exchanger, and record it as the outlet temperature of the second indoor heat exchanger; acquire the refrigerant temperature at the middle of the outdoor heat exchanger, and record it as the middle temperature of the outdoor heat exchanger; and acquire the refrigerant temperature at the outlet of the outdoor heat exchanger, and record it as the outlet temperature of the outdoor heat exchanger. The control unit is further configured to determine the difference between the low-temperature suction temperature of the compressor and the outlet temperature of the second indoor heat exchanger as the low-temperature suction superheat of the compressor; to determine the difference between the high-temperature suction temperature of the compressor and the outlet temperature of the first indoor heat exchanger as the high-temperature suction superheat of the compressor; and to determine the difference between the intermediate temperature of the outdoor heat exchanger and the outlet temperature of the outdoor heat exchanger as the subcooling of the outdoor heat exchanger. The control unit is further configured to adjust the opening value of the second electronic expansion valve based on the low-temperature suction superheat of the compressor and the high-temperature suction superheat of the compressor; and / or to adjust the opening value of the third electronic expansion valve based on the low-temperature suction superheat of the compressor and the high-temperature suction superheat of the compressor; and / or to adjust the opening value of the first electronic expansion valve based on the subcooling of the outdoor heat exchanger.

9. An air conditioning system, characterized in that, include: The control device for the air conditioning system as described in claim 8.

10. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the control method of the air conditioning system according to any one of claims 1 to 7.

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