Multi-split machine heating refrigerant quantity uniform distribution control system and method

Abstract

The invention provides a multi-split machine heating refrigerant quantity uniform distribution control system and method, and the system comprises a heat exchange module which is used for carrying out heat exchange between a refrigerant and indoor air; the control module is connected with the heat exchange module and is used for uniformly controlling the distribution of the refrigerant; the operating valves are arranged on the main gas pipe and the main liquid pipe; the first indoor unit and the second indoor unit are both connected with the control module through a main air pipe, are both connected with the heat exchange module through a main liquid pipe, and are used for carrying out heat exchange with a refrigerant so as to realize heating of an indoor space; the filter is arranged on the main liquid pipe branch and used for removing impurities in the refrigerant; and the supercooling coil dissipates heat in the high-temperature and high-pressure refrigerant discharged by the compressor into outdoor air, so that the refrigerant is condensed into liquid. By adjusting the electronic expansion valves, it can be ensured that refrigerants are evenly distributed among the multiple indoor units, and the heating effect of each indoor unit can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of intelligent control technology, and in particular to a control system and method for uniformly distributing the amount of heat and refrigerant in a multi-connected machine. Background Art

[0002] With the advancement of technology and the improvement of people's living standards, multi-split air conditioning systems have been widely used in the market due to their flexibility and energy saving. However, in actual use, multi-split air conditioning systems have some problems in heating mode, especially the uneven distribution of refrigerant, which causes differences in heating effects and refrigerant noise, which seriously affects the user experience and the overall efficiency of the system.

[0003] In a multi-split air conditioning system, one outdoor unit is connected to multiple indoor units, and the high-temperature and high-pressure refrigerant gas discharged by the compressor is transported to each indoor unit through the main pipe and branch pipe. However, due to the different lengths of the pipes connected to each indoor unit and the height differences in the installation positions of the indoor units, uneven refrigerant distribution often occurs. This uneven distribution will not only reduce the heating effect of some indoor units, greatly reducing the user experience, but also cause noise when the refrigerant flows due to insufficient supercooling, the so-called "refrigerant noise", which further affects the user comfort. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a control system and method for uniformly distributing the amount of refrigerant in a multi-split unit. By adjusting the electronic expansion valve, it is possible to ensure that the refrigerant is evenly distributed among multiple indoor units, which can significantly improve the heating effect of each indoor unit.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0006] In a first aspect, a control system for uniformly distributing hot and cold media in a multi-connected mechanism comprises:

[0007] A heat exchange module, used for exchanging heat between the refrigerant and the indoor air;

[0008] A control module, connected to the heat exchange module, for uniformly controlling the distribution of the refrigerant;

[0009] An operating valve is arranged on the main gas pipe and the main liquid pipe;

[0010] The first indoor unit and the second indoor unit are both connected to the control module through a main gas pipe and are both connected to the heat exchange module through a main liquid pipe, and are used to perform heat exchange with the refrigerant to achieve heating of the indoor space;

[0011] A filter is provided on the main liquid pipe branch to remove impurities in the refrigerant;

[0012] The supercooling coil dissipates the heat in the high-temperature and high-pressure refrigerant discharged from the compressor into the outdoor air, causing the refrigerant to condense into liquid.

[0013] Furthermore, the heat exchange module includes several heat exchangers, one end of the heat exchanger is connected to the subcooling pipe, and the other end is connected to the control module; the subcooling pipe is connected to the outdoor electronic expansion valve, filters are provided on both sides of the outdoor electronic expansion valve, one end of the outdoor electronic expansion valve is connected to the heat exchange module through the filter, and the other end is connected to the subcooling coil and the third outdoor electronic expansion valve of the subcooling coil through the filter.

[0014] Furthermore, the control module includes:

[0015] Four-way valve;

[0016] A gas-liquid separator connected to the four-way valve;

[0017] A compressor connected to the gas-liquid separator;

[0018] An oil separator, one end of which is connected to the compressor, the bottom of the oil separator is connected to a filter, and the filter is connected to a supercooling coil. The oil separator is connected to a gas-liquid separator through the filter and two supercooling coils, and the two supercooling coils are connected in parallel, and a control valve is provided at one end of one of the supercooling coils;

[0019] An oil separator, one end of which is connected to the compressor, the bottom of the oil separator is connected to a filter, and the filter is connected to a supercooling coil, and the oil separator is connected to a gas-liquid separator through the filter and the supercooling coil;

[0020] A one-way valve connected to the oil separator, wherein the one-way valve and the oil separator are provided with valves;

[0021] One end of the high-pressure sensor is connected to the one-way valve and the other end is connected to the four-way valve.

[0022] Further, the first indoor unit includes a first distributor assembly and a first indoor electronic expansion valve, the first distributor assembly is connected to the main gas pipe through a first gas pipe branch pipe; filters are provided on both sides of the first indoor electronic expansion valve, one end of the first indoor electronic expansion valve is connected to the first distributor assembly through the filter, and the other end is connected to the first liquid branch pipe through the filter, and the first liquid branch pipe is connected to the main liquid pipe;

[0023] The second indoor unit includes a second distributor assembly and a second indoor electronic expansion valve, and the second distributor assembly is connected to the main air pipe through a second air pipe branch; filters are provided on both sides of the second indoor electronic expansion valve, one end of the second indoor electronic expansion valve is connected to the second distributor assembly through the filter, and the other end is connected to the second liquid branch through the filter, and the second liquid branch is connected to the main liquid pipe.

[0024] Furthermore, the first indoor unit and the second indoor unit are connected to the subcooling coil through a main liquid pipe; the cooling coil is connected to an outdoor electronic expansion valve; the four-way valve is connected to the subcooling coil, and is connected to the third outdoor electronic expansion valve through the subcooling coil; a filter is provided at one end of the third outdoor electronic expansion valve, and is connected to the filter of the outdoor electronic expansion valve through the filter.

[0025] Furthermore, the first indoor unit and the second indoor unit are provided with temperature sensors for detecting the temperature at the outlet of the indoor unit heat exchanger.

[0026] In a second aspect, a method for controlling uniform distribution of hot and cold media in a multi-split unit is provided, which uniformly controls operating conditions according to the distribution of cold media between the internal units, including:

[0027] Setting the indoor unit to an outdoor heating mode, the outdoor heating mode including: non-refrigeration defrosting, non-defrosting control and non-heating oil return control, and confirming that all indoor unit components in the temperature control on state have been running continuously for at least 5 minutes, wherein the indoor unit components include a first indoor unit (10) and a second indoor unit (11);

[0028] After all indoor units with temperature control turned on have been running for 5 minutes, when the high pressure detected by the high pressure sensor is greater than 2.5MPa, the difference between the highest and lowest values ​​of the temperature sensor temperature of the heat exchanger in all indoor units with temperature control turned on is ≥5℃, and it continues to meet the requirement for 10 minutes, during which the signal is collected once a minute to obtain the operating conditions for uniform control of refrigerant distribution between indoor units, wherein the broadcast parameter temperature is adjusted by the difference between the highest and lowest values ​​of the temperature sensor temperature, the adjustment range is 3-10℃, and the unit is 1℃; the number of indoor units with temperature control turned on is ≥2, and at least 50% of the total capacity of indoor units are in the on state;

[0029] Furthermore, according to the refrigerant distribution between the internal units, the operating conditions are uniformly controlled to obtain a method for uniformly controlling the refrigerant distribution between the internal units, including:

[0030] According to the operating conditions of uniform refrigerant distribution control between indoor units, adjust the valve opening of the electronic expansion valve of the indoor unit so that the adjusted valve opening is ≥100; and maintain the difference between the highest and lowest values ​​of the high pressure and the temperature sensor temperature according to the valve opening, maintain a certain refrigerant flow rate, so as to obtain uniform refrigerant distribution between indoor units;

[0031] According to the uniform distribution of refrigerant between indoor units, exit conditions are set, including the start of defrost control, compressor shutdown, changes in the number of indoor units with temperature control turned on, and only one indoor unit with temperature control turned on.

[0032] Furthermore, the operating conditions for uniform control of refrigerant distribution of the whole machine include:

[0033] Set the calculation of the four-way valve opening, the compressor running time> 10 minutes; after the defrost control is completed, the time starts from the four-way valve opening again, and the full 10 minutes; and after the heating oil return control is completed, the time also starts from the four-way valve opening again, and the full 10 minutes;

[0034] Set the indoor unit to outdoor heating mode and confirm that all indoor unit components in the temperature control on state have been running continuously for at least 5 minutes;

[0035] After all the indoor units with temperature control turned on have been running continuously for 5 minutes, when the high pressure detected by the high pressure sensor is greater than 2.5MPa, the difference between the highest and lowest values ​​of the temperature sensor temperature of the heat exchanger in all the indoor units with temperature control turned on is ≥5℃, the valve opening of the indoor unit EEV=470; the difference between the set temperature and the temperature value of the indoor unit with temperature control turned on is >15℃, and the difference between the temperature difference and the set temperature is >20℃ for 5 minutes to obtain the operating conditions for uniform control of refrigerant distribution of the whole machine.

[0036] Furthermore, according to the operating conditions for uniform control of refrigerant distribution of the whole machine, the operating conditions for uniform control of refrigerant distribution of the whole machine are realized, including:

[0037] According to the operating conditions of uniform refrigerant distribution control of the whole machine, the target high pressure is changed to 3.15MPa, and the target superheat of the outdoor unit is reduced to 1.5℃ to achieve uniform refrigerant distribution of the whole system;

[0038] According to the uniform distribution of refrigerant in the whole system, the exit conditions are set, including the start of defrost control, compressor shutdown, change in the number of indoor units with temperature control turned on, heating oil return control and the difference between the temperature difference and the set temperature ≤15℃.

[0039] The above solution of the present invention includes at least the following beneficial effects:

[0040] By adjusting the indoor electronic expansion valve, the refrigerant can be evenly distributed among multiple indoor units. By increasing the compressor frequency and increasing the opening of the outdoor electronic expansion valve, it not only helps to evenly distribute the refrigerant among the whole unit, but also increases the supercooling of each indoor unit. By finely adjusting the main components in the multi-split system, including the indoor electronic expansion valve and the outdoor electronic expansion valve, and adjusting the compressor frequency, through precise control of the key components in the multi-split system, the problem of uneven refrigerant distribution can be solved and the refrigerant noise can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a diagram of a control system for uniformly distributing the amount of heating and refrigerant in a multi-connected machine provided by an embodiment of the present invention.

[0042] Figure 2This is a flow curve diagram of a valve with a valve aperture of 1.8 mm and a front-to-back pressure difference of 0.98 MPa used in a multi-unit heating and cooling medium uniform distribution control system provided by an embodiment of the present invention, and with different valve step numbers.

[0043] 1. Heat exchange module; 2. Gas-liquid separator; 3. Compressor; 4. Control module; 5. Oil separator; 6. One-way valve; 7. High-pressure sensor; 8. Four-way valve; 9. Operating valve; 10. First indoor unit; 11. Second indoor unit; 12. Outdoor electronic expansion valve; 13. Heat exchanger; 14. Filter; 15. Subcooling pipe; 16. Subcooling coil; 17. Third outdoor electronic expansion valve; 101. First indoor electronic expansion valve; 102. First distributor assembly; 1101. Second indoor electronic expansion valve; 1102. Second distributor assembly; 18. Control valve. DETAILED DESCRIPTION

[0044] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in a form and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0045] like Figure 1 As shown, an embodiment of the present invention provides a control system for uniformly distributing heat and refrigerant in a multi-connected machine, comprising:

[0046] The heat exchange module 1 is used to perform heat exchange between the refrigerant and the indoor air;

[0047] The control module 4 is connected to the heat exchange module 1 and is used to evenly control the distribution of the refrigerant;

[0048] An operating valve 9 is provided on the main gas pipe and the main liquid pipe;

[0049] The first indoor unit 10 and the second indoor unit 11 are both connected to the control module 4 through the main gas pipe, and are both connected to the heat exchange module 1 through the main liquid pipe, and are used to perform heat exchange with the refrigerant to achieve heating of the indoor space;

[0050] The filter 14 is arranged on the main liquid pipe branch and is used to remove impurities in the refrigerant;

[0051] The subcooling coil 16 dissipates the heat in the high-temperature and high-pressure refrigerant discharged from the compressor into the outdoor air, so that the refrigerant condenses into liquid.

[0052] In the embodiment of the present invention, the design of the heat exchange module 1 enables the refrigerant to perform efficient heat exchange with the indoor air, which helps to quickly adjust the indoor temperature. The existence of the control module 4 enables the system to achieve uniform distribution control of the refrigerant between the internal machines and the entire system. The operating valve 9 is set on the main air pipe and the main liquid pipe. By adjusting these valves, the flow of the refrigerant can be easily controlled. The first indoor unit 10 and the second indoor unit 11 are connected to the control module 4 and the heat exchange module 1 through an optimized connection method, ensuring efficient heat exchange with the refrigerant. The filter 14 is set on the main liquid pipe branch to effectively remove impurities in the refrigerant. The design of the supercooling coil 16 enables the heat in the high-temperature and high-pressure refrigerant discharged by the compressor to be efficiently dissipated to the outdoor air, realizing rapid condensation of the refrigerant. This helps to reduce the temperature pressure of the system and improve operating efficiency.

[0053] In a preferred embodiment of the present invention, the heat exchange module 1 includes a plurality of heat exchangers 13, one end of the heat exchanger 13 is connected to the subcooling pipe 15, and the other end is connected to the control module 4; the subcooling pipe 15 is connected to the outdoor electronic expansion valve 12, and filters 14 are provided on both sides of the outdoor electronic expansion valve 12. One end of the outdoor electronic expansion valve 12 is connected to the heat exchange module 1 through the filter 14, and the other end is connected to the subcooling coil 16 and the third outdoor electronic expansion valve 17 of the subcooling coil through the filter 14.

[0054] In the embodiment of the present invention, the heat exchange module 1 includes a plurality of heat exchangers 13, which increases the surface area of ​​heat exchange, thereby improving the heat exchange efficiency between the refrigerant and the indoor air. The connection design of the subcooling pipe 15 and the heat exchanger 13, as well as the precise control of the outdoor electronic expansion valve 12, enables the refrigerant to be sufficiently supercooled before entering the indoor unit, thereby improving the refrigeration effect, and also helps to reduce the energy loss of the refrigerant during the transmission process. Filters 14 are provided on both sides of the outdoor electronic expansion valve 12, which can effectively remove impurities in the refrigerant and protect the heat exchanger 13 and other system components from the influence of impurities. Through reasonable layout and connection design, as well as precise control of the subcooling coil 16 and the outdoor electronic expansion valve 17, the entire system can operate stably under various environmental conditions, providing continuous and efficient cooling or heating effects.

[0055] In a specific embodiment of the present invention, the heat exchange module 1 includes two heat exchangers 13, and the heat exchanger 13 is connected to the subcooling pipe 15 at one end, allowing the refrigerant flowing through the subcooling pipe 15 to directly enter the heat exchanger 13 for heat exchange; the other end of the heat exchanger 13 is connected to the control module 4. The control module 4 is responsible for regulating the distribution of the refrigerant to ensure that each heat exchanger 13 can obtain an appropriate amount of refrigerant to achieve efficient heat exchange. The subcooling pipe 15 is directly connected to the outdoor electronic expansion valve 12 for accurately adjusting the flow and pressure of the refrigerant. Filters 14 are provided on both sides of the outdoor electronic expansion valve 12. The main function of the filter 14 is to remove impurities in the refrigerant and protect subsequent components (such as the heat exchanger 13 and the subcooling coil 16) from contamination and damage. The filter 14 at one end is connected between the outdoor electronic expansion valve 12 and the heat exchange module 1 to ensure that the refrigerant entering the heat exchange module 1 is pure, and the filter 14 at the other end is connected between the outdoor electronic expansion valve 12 and the subcooling coil 16, which also plays a role in purifying the refrigerant. The subcooling coil 16 is connected to the outdoor electronic expansion valve 12. The subcooling coil 16 is also equipped with a special outdoor electronic expansion valve 17 for controlling the flow and pressure of the refrigerant during the subcooling process to ensure that the subcooling effect is optimal.

[0056] In a preferred embodiment of the present invention, the control module 4 includes:

[0057] Four-way valve 4;

[0058] A gas-liquid separator 2 connected to the four-way valve 4;

[0059] A compressor 3 connected to the gas-liquid separator 2;

[0060] The oil separator 5 has one end connected to the compressor 3, the bottom of the oil separator 5 is connected to a filter 14, and the filter 14 is connected to a subcooling coil 16. The oil separator 5 is connected to the gas-liquid separator 2 through the filter 14 and two subcooling coils 16, and the two subcooling coils 16 are connected in parallel, and a control valve 18 is provided at one end of one of the subcooling coils 16;

[0061] A one-way valve 6 connected to the oil separator 5, wherein the one-way valve 6 and the oil separator 5 are provided with valves;

[0062] One end of the high pressure sensor 7 is connected to the one-way valve 6 , and the other end is connected to the four-way valve 4 .

[0063] In the embodiment of the present invention, through the control of the four-way valve 4, the system can realize the rapid switching of the cooling and heating modes, and improve the energy conversion efficiency. At the same time, the gas-liquid separator 2 ensures that the refrigerant entering the compressor 3 is in a gaseous state, preventing the liquid refrigerant from damaging the compressor, thereby extending the service life of the compressor and improving its energy efficiency. The design of the oil separator 5 enables the lubricating oil in the refrigerant discharged from the compressor 3 to be effectively separated, ensuring the recovery and reuse of the lubricating oil, and also preventing the oil from polluting other parts of the system. The filter 14 connected to the bottom of the oil separator 5 removes impurities and tiny particles in the refrigerant, ensuring that the refrigerant entering the supercooling coil 16 is pure. The setting of the one-way valve 6 prevents the reverse flow of the refrigerant and ensures the safe operation of the system. At the same time, the valve control between the oil separator 5 makes the refrigerant flow more flexible and controllable, and the high-pressure sensor 7 monitors the pressure changes of the system in real time and feeds the signal back to the control system.

[0064] In a specific embodiment of the present invention, the four-way valve 4 is directly connected to the gas-liquid separator 2, the main air pipe, the high-pressure sensor 7 and the heat exchange module 1. The four-way valve 4 is connected to the gas-liquid separator 2 to ensure that the refrigerant recovered from the system can smoothly enter the gas-liquid separator 2 for separation. The gas-liquid separator 2 is connected between the four-way valve 4 and the compressor 3. Its main function is to separate the refrigerant before entering the compressor 3 into gas and liquid, ensuring that only gaseous refrigerant enters the compressor. The compressor 3 is the power source of the air-conditioning system and is responsible for compressing the refrigerant and increasing its temperature and pressure. The inlet of the compressor 3 is connected to the gas-liquid separator 2 to ensure that pure gaseous refrigerant is inhaled. The outlet is connected to the oil separator 5, and the compressed high-temperature and high-pressure refrigerant is sent to the oil separator 5. One end of the oil separator 5 is connected to the outlet of the compressor 3 to receive the high-temperature and high-pressure refrigerant and lubricating oil mixture. The bottom of the oil separator 5 is connected to two subcooling coils 16 through a filter 14, one of which is provided with a control valve 18, which is adjusted according to the system flow. The other end of the subcooling coil 16 is connected to the gas-liquid separator 2 to form a cycle; the check valve 6 is connected between the oil separator 5 and the high-pressure sensor 7, and its function is to prevent the refrigerant from flowing in reverse. A valve is provided between the check valve 6 and the oil separator 5 to control the flow of the refrigerant. The high-pressure sensor 7 is used to monitor the high-pressure side pressure of the system. One end is connected to the check valve 6 to receive the high-pressure refrigerant from the compressor 3, and the other end is connected to the four-way valve 4 to form a closed-loop control system to adjust the working state of the four-way valve 4 according to the pressure change.

[0065] In a preferred embodiment of the present invention, the first indoor unit 10 includes a first distributor assembly 102 and a first indoor electronic expansion valve 101, wherein the first distributor assembly 102 is connected to the main gas pipe via a first gas pipe branch; filters 14 are provided on both sides of the first indoor electronic expansion valve 101, one end of the first indoor electronic expansion valve 101 is connected to the first distributor assembly 102 via the filter 14, and the other end is connected to the first liquid branch via the filter 14, and the first liquid branch is connected to the main liquid pipe;

[0066] The second indoor unit 11 includes a second distributor assembly 1102 and a second indoor electronic expansion valve 1101, and the second distributor assembly 1102 is connected to the main air pipe through a second air pipe branch; filters 14 are provided on both sides of the second indoor electronic expansion valve 1101, one end of the second indoor electronic expansion valve 1101 is connected to the second distributor assembly 1102 through the filter 14, and the other end is connected to the second liquid branch through the filter 14, and the second liquid branch is connected to the main liquid pipe.

[0067] In the embodiment of the present invention, the first indoor unit 10 and the second indoor unit 11 both adopt a similar modular design, including key components such as a distributor assembly and an electronic expansion valve; the distributor assembly can ensure that the refrigerant is evenly and efficiently distributed inside the indoor unit. The indoor electronic expansion valve can accurately control the flow and pressure of the refrigerant to adapt to changes in the indoor environment. The filters 14 are arranged on both sides of the indoor electronic expansion valve to effectively remove impurities and particulate matter in the refrigerant and keep the system clean. The modular design and clear connection layout make the first indoor unit and the second indoor unit easier to maintain and manage.

[0068] In a specific embodiment of the present invention, the distributor assembly 102 is a key component of the first indoor unit 10, which is responsible for the distribution and regulation of the refrigerant. The distributor assembly 102 is connected to the main air pipe through the first air pipe branch. In this way, the gaseous refrigerant transported from the main air pipe can enter the first distributor assembly 102, and then be distributed to various parts of the indoor unit. One end of the first indoor electronic expansion valve 101 is connected to the first distributor assembly 102 through the filter 14, and the liquid refrigerant flowing out of the first distributor assembly 102 can be filtered by the filter 14 and then enter the first indoor electronic expansion valve 101. The other end of the first indoor electronic expansion valve 101 is also provided with a filter 14, and is connected to the first liquid branch through this filter. The liquid refrigerant regulated by the first indoor electronic expansion valve 101 will be filtered again, and then flow into the main liquid pipe through the first liquid branch.

[0069] In another specific embodiment of the present invention, the function of the second distributor assembly 1102 is similar to that of the first distributor assembly 102 in the first indoor unit. The second distributor assembly 1102 is connected to the main air pipe through the second air pipe branch, thereby receiving the gaseous refrigerant transported from the main air pipe. One end of the second indoor electronic expansion valve 1101 is connected to the second distributor assembly 1102 through the filter 14 to receive the liquid refrigerant flowing out of the distributor assembly. The other end of the second indoor electronic expansion valve 1101 is also connected to the second liquid branch through the filter 14. The regulated liquid refrigerant will be filtered and then flow back to the main liquid pipe through the second liquid branch.

[0070] In a preferred embodiment of the present invention, the first indoor unit 10 and the second indoor unit 11 are connected to the subcooling coil 16 through a main liquid pipe; the cooling coil 16 is connected to the outdoor electronic expansion valve 12; the four-way valve 4 is connected to the subcooling coil 16, and is connected to the third outdoor electronic expansion valve 17 of the subcooling coil through the subcooling coil 16; a filter 14 is provided at one end of the third outdoor electronic expansion valve 17, and is connected to the filter 14 of the outdoor electronic expansion valve 12 through the filter 14.

[0071] In an embodiment of the present invention, the first indoor unit 10 and the second indoor unit 11 are directly connected to the subcooling coil 16 through the main liquid pipe, so that the refrigerant returning from the indoor unit can be quickly cooled again through the subcooling coil; the subcooling coil 16 is connected to the outdoor electronic expansion valve 12, allowing the refrigerant flow rate during the subcooling process to be accurately controlled; the connection between the four-way valve 4 and the subcooling coil 16 enables the system to flexibly switch between different working modes (such as cooling and heating); a filter 14 is provided at one end of the third outdoor electronic expansion valve 17, and is connected to the filter 14 of the outdoor electronic expansion valve 12, forming a double filtration system.

[0072] In a specific embodiment of the present invention, the first indoor unit 10 and the second indoor unit 11 are connected to the subcooling coil 16 through the main liquid pipe. The output end of the subcooling coil 16 is connected to the outdoor electronic expansion valve 12. After the liquid refrigerant is cooled by the subcooling coil 16, it will flow into the outdoor electronic expansion valve 12, and one connection port of the four-way valve 4 is connected to the subcooling coil 16, and is connected to the third outdoor electronic expansion valve 17 through the subcooling coil 16. The four-way valve 4 is allowed to control whether the refrigerant flows through the subcooling coil 16 and the outdoor electronic expansion valve 17 according to the working mode of the system (cooling or heating), and a filter 14 is provided at one end of the third outdoor electronic expansion valve 17. This filter 14 is also connected to the filter 14 of the outdoor electronic expansion valve 12 through a pipeline.

[0073] In a preferred embodiment of the present invention, the first indoor unit 10 and the second indoor unit 11 are provided with temperature sensors for detecting the temperature at the outlet of the indoor unit heat exchanger.

[0074] In the embodiment of the present invention, the temperature sensor can monitor the temperature at the outlet of the heat exchanger in real time, thereby ensuring that the air temperature provided by the indoor unit is consistent with the set temperature. By accurately sensing the indoor temperature, the air conditioning system can more intelligently adjust the cooling or heating power, and the real-time monitoring function of the temperature sensor helps prevent overheating or overcooling of the indoor unit. Once an abnormal temperature is detected, the system can respond immediately. By responding to temperature changes in a timely manner, the air conditioning system can avoid damage to the equipment caused by extreme temperatures, thereby extending the service life of the equipment.

[0075] A method for controlling the uniform distribution of hot and cold media in a multi-split unit, which uniformly controls the operating conditions according to the distribution of cold media between the internal units, comprises:

[0076] The indoor unit is set to outdoor heating mode, which includes: non-refrigeration defrosting, non-defrosting control and non-heating oil return control, and confirms that all indoor unit components in the temperature control on state have been running for at least 5 minutes, wherein the indoor unit components include a first indoor unit 10 and a second indoor unit 11;

[0077] After all indoor units with temperature control turned on have been running for 5 minutes, when the high pressure detected by the high pressure sensor is greater than 2.5MPa, the difference between the highest and lowest values ​​of the temperature sensor temperature of the heat exchanger in all indoor units with temperature control turned on is ≥5℃, and it continues to meet the requirement for 10 minutes, during which the signal is collected once a minute to obtain the operating conditions for uniform control of refrigerant distribution between indoor units, wherein the broadcast parameter temperature is adjusted by the difference between the highest and lowest values ​​of the temperature sensor temperature, the adjustment range is 3-10℃, and the unit is 1℃; the number of indoor units with temperature control turned on is ≥2, and at least 50% of the total capacity of indoor units are in the on state;

[0078] In an embodiment of the present invention, by precisely controlling the operation mode and response conditions of the indoor unit, the system can utilize energy more efficiently. In modes such as non-refrigeration defrosting, non-defrosting control, and non-heating oil return control, the system can avoid unnecessary energy consumption; by monitoring the data of the high-pressure sensor and the temperature sensor of the indoor unit heat exchanger, the system can more accurately grasp the distribution of refrigerant among the indoor units. By setting specific operating conditions and parameters, such as high-pressure thresholds and temperature differences of the temperature sensors, the system can respond in a timely manner in abnormal situations to avoid equipment damage or performance degradation. By precisely controlling the temperature and operation mode of the indoor unit, the system can provide users with a more comfortable and stable indoor environment. By collecting and analyzing the operating data of the indoor unit components, the system can achieve more intelligent management.

[0079] In a preferred embodiment of the present invention, according to the refrigerant distribution between the internal units, the operating conditions are uniformly controlled to obtain a method for uniformly controlling the refrigerant distribution between the internal units, including:

[0080] According to the operating conditions of uniform refrigerant distribution control between indoor units, adjust the valve opening of the electronic expansion valve of the indoor unit so that the adjusted valve opening is ≥100; and maintain the difference between the highest and lowest values ​​of the high pressure and the temperature sensor temperature according to the valve opening, maintain a certain refrigerant flow rate, so as to obtain uniform refrigerant distribution between indoor units;

[0081] According to the uniform distribution of refrigerant between indoor units, exit conditions are set, including the start of defrost control, compressor shutdown, changes in the number of indoor units with temperature control turned on, and only one indoor unit with temperature control turned on.

[0082] In an embodiment of the present invention, by adjusting the opening of the indoor valve, it is possible to ensure that the refrigerant is more evenly distributed among the indoor units. When the system detects that the difference between the highest and lowest values ​​of the high pressure and the temperature of the temperature sensor reaches the set condition, timely adjustment of the valve opening can quickly change the refrigerant flow rate, so that the system can reach a stable state faster. By accurately controlling the valve opening and the refrigerant flow rate, the system can minimize energy consumption and refrigerant waste while meeting user needs. This helps to reduce operating costs and achieve more environmentally friendly and energy-saving air-conditioning operation. Reasonable valve opening adjustment and exit condition setting can avoid damage to the system due to excessive pressure or temperature fluctuations, thereby extending the service life of the equipment. At the same time, this also reduces the frequency of repairs and replacement of parts and reduces maintenance costs. By ensuring the uniform distribution of refrigerant and timely responding to temperature changes, a more comfortable and stable indoor environment is provided.

[0083] In a preferred embodiment of the present invention, the operating conditions for uniformly controlling the refrigerant distribution of the whole machine include:

[0084] Set the calculation of the four-way valve opening, the compressor running time> 10 minutes; after the defrost control is completed, the time starts from the four-way valve opening again, and the full 10 minutes; and after the heating oil return control is completed, the time also starts from the four-way valve opening again, and the full 10 minutes;

[0085] Set the indoor unit to outdoor heating mode and confirm that all indoor unit components in the temperature control on state have been running continuously for at least 5 minutes;

[0086] After all the indoor units with temperature control turned on have been running continuously for 5 minutes, when the high pressure detected by the high pressure sensor is greater than 2.5MPa, the difference between the highest and lowest values ​​of the temperature sensor temperature of the heat exchanger in all the indoor units with temperature control turned on is ≥5℃, the valve opening of the indoor unit EEV=470; the difference between the set temperature and the temperature value of the indoor unit with temperature control turned on is >15℃, and the difference between the temperature difference and the set temperature is >20℃ for 5 minutes to obtain the operating conditions for uniform control of refrigerant distribution of the whole machine.

[0087] In an embodiment of the present invention, by precisely controlling the opening time of the four-way valve and the running time of the compressor, the system can operate more efficiently. Ensure that the compressor works in the best state, avoid unnecessary energy consumption and wear, and thus improve the overall efficiency. After the defrost control and the heating oil return control are completed, the timing starts from the opening of the four-way valve again to ensure that the system has enough time to stabilize and recover. By setting specific operating conditions, such as the high pressure detected by the high-pressure sensor is greater than 2.5MPa, and the difference between the highest and lowest values ​​of the temperature of the heat exchanger temperature sensor, the system can more accurately control the distribution of refrigerant between each indoor unit. By monitoring and controlling multiple key parameters, such as the opening of the indoor valve, temperature difference, etc., the system can respond in time in abnormal situations to avoid equipment damage or performance degradation. This helps to enhance the stability and reliability of the system and reduce the possibility of failure. By precisely controlling the temperature of the indoor unit and the distribution of refrigerant, the system can provide users with a more comfortable and stable indoor environment.

[0088] In a preferred embodiment of the present invention, according to the operating conditions for uniform control of refrigerant distribution of the whole machine, the operating conditions for uniform control of refrigerant distribution of the whole machine are implemented, including:

[0089] According to the operating conditions of uniform refrigerant distribution control of the whole machine, the target high pressure is changed to 3.15MPa, and the target superheat of the outdoor unit is reduced to 1.5℃ to achieve uniform refrigerant distribution of the whole system;

[0090] According to the uniform distribution of refrigerant in the whole system, the exit conditions are set, including the start of defrost control, compressor shutdown, changes in the number of indoor units with temperature control turned on, heating oil return control and the difference between the temperature difference and the set temperature ≤15℃.

[0091] In an embodiment of the present invention, by changing the target high pressure to 3.15MPa, it is possible to operate at a higher pressure, which helps to improve the heat exchange efficiency, thereby achieving better cooling or heating effects at the same energy consumption. At the same time, lowering the target superheat of the outdoor unit to 1.5°C can reduce unnecessary energy consumption and improve overall energy efficiency. Through carefully set exit conditions, such as defrost control startup and compressor shutdown, the system can respond in a timely manner when encountering potential problems or abnormal conditions to avoid equipment damage or performance degradation. By adjusting the target high pressure and superheat, the system can better control the flow and distribution of the refrigerant, ensuring that each indoor unit can obtain the required amount of refrigerant, which helps to achieve more uniform temperature control, improve the utilization efficiency of the refrigerant, and reduce waste.

[0092] Figure 2 This is a flow curve diagram for electronic expansion valves with different valve steps. The measured pressure difference is 0.98MPA with the medium being air. If this electronic expansion valve is used in a refrigerant system, the flow rate will be different due to the different pressure difference before and after the valve body and the different medium, but the trend is the same.

[0093] Number of pulses flow 0 0 10 0 20 0.23 30 3.62 40 5.49 50 6.74 60 8.1 70 9.43 80 10.65 90 11.91 100 13.26 125 16.12 150 18.83 175 21.74 200 24.12 250 28.82 300 33.27 350 37.17 400 40.6 450 43.62 500 46.36

[0094] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A control system for uniform distribution of refrigerant in a multi-unit heating system, characterized in that: include: A heat exchange module (1) is used to perform heat exchange between the refrigerant and the indoor air; A control module (4) connected to the heat exchange module (1) and used to evenly control the distribution of the refrigerant; An operating valve (9) is arranged on the main gas pipe and the main liquid pipe; The first indoor unit (10) and the second indoor unit (11) are both connected to the control module (4) via a main gas pipe, and are both connected to the heat exchange module (1) via a main liquid pipe, and are used to perform heat exchange with the refrigerant to achieve heating of the indoor space; A filter (14) is arranged on the main liquid pipe branch and is used to remove impurities in the refrigerant; The subcooling coil (16) dissipates heat from the high-temperature and high-pressure refrigerant discharged from the compressor into the outdoor air, thereby condensing the refrigerant into liquid.

2. The multi-unit heating and refrigerant uniform distribution control system according to claim 1 is characterized in that: The heat exchange module (1) comprises a plurality of heat exchangers (13), one end of the heat exchanger (13) being connected to a subcooling pipe (15), and the other end being connected to a control module (4); the subcooling pipe (15) being connected to an outdoor electronic expansion valve (12), both sides of the outdoor electronic expansion valve (12) being provided with filters (14); one end of the outdoor electronic expansion valve (12) being connected to the heat exchange module (1) via the filter (14), and the other end being connected to a subcooling coil (16) and a third outdoor electronic expansion valve (17) of the subcooling coil via the filter (14).

3. The multi-unit heating and refrigerant uniform distribution control system according to claim 2 is characterized in that: The control module (4) comprises: Four-way valve (4); A gas-liquid separator (2) connected to the four-way valve (4); A compressor (3) connected to the gas-liquid separator (2); An oil separator (5) is connected to the compressor (3) at one end, the bottom of the oil separator (5) is connected to a filter (14), and the filter (14) is connected to a supercooling coil (16). The oil separator (5) is connected to the gas-liquid separator (2) via the filter (14) and two supercooling coils (16), and the two supercooling coils (16) are connected in parallel, and a control valve (18) is provided at one end of one of the supercooling coils (16); A one-way valve (6) is connected to the oil separator (5), wherein the one-way valve (6) and the oil separator (5) are provided with valves; A high pressure sensor (7) has one end connected to the one-way valve (6) and the other end connected to the four-way valve (4).

4. The multi-unit heating and refrigerant uniform distribution control system according to claim 3 is characterized in that: The first indoor unit (10) comprises a first distributor assembly (102) and a first indoor electronic expansion valve (101); the first distributor assembly (102) is connected to the main gas pipe via a first gas pipe branch; filters (14) are provided on both sides of the first indoor electronic expansion valve (101); one end of the first indoor electronic expansion valve (101) is connected to the first distributor assembly (102) via the filter (14), and the other end is connected to the first liquid branch via the filter (14); the first liquid branch is connected to the main liquid pipe; The second indoor unit (11) comprises a second distributor assembly (1102) and a second indoor electronic expansion valve (1101); the second distributor assembly (1102) is connected to the main gas pipe via a second gas pipe branch; filters (14) are provided on both sides of the second indoor electronic expansion valve (1101); one end of the second indoor electronic expansion valve (1101) is connected to the second distributor assembly (1102) via the filter (14), and the other end is connected to the second liquid branch via the filter (14); and the second liquid branch is connected to the main liquid pipe.

5. The multi-unit heating and refrigerant uniform distribution control system according to claim 4 is characterized in that: The first indoor unit (10) and the second indoor unit (11) are connected to a subcooling coil (16) via a main liquid pipe; the cooling coil (16) is connected to an outdoor electronic expansion valve (12); the four-way valve (4) is connected to the subcooling coil (16) and is connected to a third outdoor electronic expansion valve (17) via the subcooling coil (16); a filter (14) is provided at one end of the third outdoor electronic expansion valve (17) and is connected to the filter (14) of the outdoor electronic expansion valve (12) via the filter (14).

6. The control system for uniform distribution of refrigerant quantity for a multi-unit heating machine according to claim 5 is characterized in that: The first indoor unit (10) and the second indoor unit (11) are provided with temperature sensors for detecting the temperature at the outlet of the indoor unit heat exchanger.

7. A method for controlling uniform distribution of refrigerant in a multi-unit heating system, characterized in that: In the system as claimed in any one of claims 1 to 6, the operating conditions for controlling the uniform distribution of refrigerant between internal units include: Setting the indoor unit to an outdoor heating mode, the outdoor heating mode including: non-refrigeration defrosting, non-defrosting control and non-heating oil return control, and confirming that all indoor unit components in the temperature control on state have been running continuously for at least 5 minutes, wherein the indoor unit components include a first indoor unit (10) and a second indoor unit (11); After all indoor units with temperature control turned on have been running for 5 minutes, when the high pressure detected by the high pressure sensor is greater than 2.5MPa, the difference between the highest and lowest values ​​of the temperature sensor temperature of the heat exchanger in all indoor units with temperature control turned on is ≥5℃, and it continues to be satisfied for 10 minutes. During this period, the signal is collected once a minute to obtain the operating conditions for uniform control of refrigerant distribution between indoor units, among which the broadcast parameter temperature is adjusted by the difference between the highest and lowest values ​​of the temperature sensor temperature, and the adjustment range is 3-10℃, and the unit is 1℃; the number of indoor units with temperature control turned on is ≥2, and at least 50% of the total capacity of indoor units are in the on state.

8. The method for controlling uniform distribution of refrigerant in a multi-unit heating system according to claim 7, characterized in that: According to the refrigerant distribution between the indoor units, the operating conditions are uniformly controlled to obtain a method for uniformly controlling the refrigerant distribution between the indoor units, including: According to the operating conditions of uniform refrigerant distribution control between indoor units, adjust the valve opening of the electronic expansion valve of the indoor unit so that the adjusted valve opening is ≥100, and maintain the difference between the highest and lowest values ​​of the high pressure and the temperature sensor temperature according to the valve opening, maintain a certain refrigerant flow rate, so as to obtain uniform refrigerant distribution between indoor units; According to the uniform distribution of refrigerant between indoor units, exit conditions are set, including the start of defrost control, compressor shutdown, changes in the number of indoor units with temperature control turned on, and only one indoor unit with temperature control turned on.

9. The method for controlling uniform distribution of refrigerant in a multi-unit heating machine according to claim 8, characterized in that: The operating conditions for uniform control of refrigerant distribution of the whole machine include: Set the calculation of the four-way valve opening, the compressor running time> 10 minutes; after the defrost control is completed, the time starts from the four-way valve opening again, and the full 10 minutes; and after the heating oil return control is completed, the time also starts from the four-way valve opening again, and the full 10 minutes; Set the indoor unit to outdoor heating mode and confirm that all indoor unit components in the temperature control on state have been running continuously for at least 5 minutes; After all the indoor units with temperature control turned on have been running continuously for 5 minutes, when the high pressure detected by the high pressure sensor is greater than 2.5MPa, the difference between the highest and lowest values ​​of the temperature sensor temperature of the heat exchanger in all the indoor units with temperature control turned on is ≥5℃, the valve opening of the indoor unit EEV=470, the difference between the set temperature and the temperature value of the indoor unit with temperature control turned on is >15℃, and the difference between the temperature difference and the set temperature is >20℃ for 5 minutes, so as to obtain the operating conditions for uniform control of refrigerant distribution of the whole machine.

10. The method for controlling uniform distribution of refrigerant in a multi-unit heating machine according to claim 9, characterized in that: According to the operating conditions of uniform control of refrigerant distribution of the whole machine, the operating conditions of uniform control of refrigerant distribution of the whole machine are realized, including: According to the operating conditions of uniform refrigerant distribution control of the whole machine, the target high pressure is changed to 3.15MPa, and the target superheat of the outdoor unit is reduced to 1.5℃ to obtain uniform refrigerant distribution of the whole system; According to the uniform distribution of refrigerant in the whole system, the exit conditions are set, including the start of defrost control, compressor shutdown, change in the number of indoor units with temperature control turned on, heating oil return control and the difference between the temperature difference and the set temperature ≤15℃.

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