WO2023092889A1 - Multi-split air conditioner - Google Patents

Abstract

Provided is a multi-split air conditioner, comprising a refrigerant charging device, a storage unit, and a processing unit. The refrigerant charging device is configured to charge refrigerant into a heat exchange pipeline; the internal refrigerant volume VO of an outdoor unit and the internal refrigerant volume VI of each indoor unit are stored in the storage unit; the processing unit is configured to read data VO and VI stored in the storage unit, calculate a ratio VI/VO of VO and VI, and determine a target subcooling degree SCO at an outlet of an outdoor heat exchanger (4) according to the ratio VI/VO; during a refrigerant charging process, the multi-split air conditioner monitors a supercooling degree SC at the outlet of the outdoor heat exchanger (4) in real time, and when SC ≥ SCO, the refrigerant charging device stops refrigerant charging. The present disclosure ensures that the refrigerant charging amount is appropriate, thereby avoiding the phenomenon of too little or too much refrigerant.

Description

A multi-connected air conditioner

Cross References to Related Applications

This disclosure claims priority to a Chinese patent application with application number 202111421239.2 filed with the China Patent Office on November 26, 2021, the entire contents of which are incorporated herein by reference.

technical field

The present disclosure relates to the technical field of air conditioning, in particular to a multi-connected air conditioner.

Background technique

Appropriate refrigerant charging is the basis for reliable and efficient operation of the air conditioning system. Too much or too little refrigerant is likely to cause problems such as performance degradation or even failure to operate the unit, and shortened service life. Due to the relatively long piping length of the multi-split air conditioning system, it is usually necessary to charge additional refrigerant during installation.

In the related art, the outdoor unit of the air conditioner comes with a part of refrigerant, and additionally, a proportional amount of refrigerant needs to be supplemented according to the length and diameter of the liquid pipe. When the outdoor unit is connected to an indoor unit with a large volume or a small volume, such refrigerant charging method is prone to phenomena such as too little or too much refrigerant, and is relatively poor in applicability.

Contents of the invention

Some embodiments of the present disclosure provide a multi-connected air conditioner, including a heat exchange system, a refrigerant charging device, a storage unit, and a processing unit. The heat exchange system includes a compressor connected through pipelines, a gas-liquid separator, a four-way reversing valve, an outdoor heat exchanger, and multiple indoor heat exchangers connected in parallel; Charge the refrigerant; the storage unit stores the internal refrigerant volume VO of the outdoor unit and the internal refrigerant volume VI of each indoor unit; the processing unit is configured to read the internal refrigerant volume data VO of the outdoor unit and the internal refrigerant volume of the indoor units stored in the storage unit data VI, and calculate the ratio VI/VO of the two, and determine the target subcooling degree SCO at the outlet of the outdoor heat exchanger according to the ratio VI/VO; among them, the refrigerant charging device is in the process of refrigerant charging, and the multi-connected air conditioner is real-time Monitor the subcooling degree SC at the outlet of the outdoor heat exchanger, and stop refrigerant charging when SC≥SCO.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following will briefly introduce the drawings that need to be used in the embodiments. Obviously, the drawings in the following description are some embodiments of the present disclosure. Those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort.

Figure 1 is a schematic diagram of the relationship between the degree of subcooling of the air conditioner and the amount of refrigerant;

2 is a schematic diagram of the relationship between the target subcooling degree and the volume ratio VI/VO of the indoor and outdoor units according to an embodiment of the present disclosure;

Fig. 3 is a schematic diagram of the principle of a multi-connected air conditioning system according to some embodiments of the present disclosure;

FIG. 4 is another schematic diagram of a multi-connected air-conditioning system according to some embodiments of the present disclosure;

Fig. 5 is another schematic diagram of the principle of a multi-connected air-conditioning system according to some embodiments of the present disclosure;

Fig. 6 is a flow chart of automatic charging control of refrigerant in a multi-connected air conditioner according to some embodiments of the present disclosure;

FIG. 7 is a control flowchart of an electronic expansion valve according to some embodiments of the present disclosure.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are only some of the embodiments of the present disclosure, not all of them.

According to the characteristic that the subcooling degree at the outlet of the multi-connected air conditioner condenser is sensitive to the change of the amount of refrigerant, by monitoring the change of the degree of subcooling during the refrigerant charging process, the situation of the refrigerant charging amount can be indirectly obtained to ensure the best operating state of the air conditioning system .

The air conditioner performs a cooling and heating cycle of the air conditioner by using a compressor, a condenser, an expansion valve, and an evaporator. A cooling and heating cycle consists of a series of processes involving compression, condensation, expansion and evaporation to cool or heat an indoor space.

The low-temperature and low-pressure refrigerant enters the compressor, and the compressor compresses it into high-temperature and high-pressure refrigerant gas and discharges it. The discharged refrigerant gas flows into the condenser to condense into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

The expansion valve expands the high-temperature and high-pressure liquid-phase refrigerant condensed in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve, and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can realize the refrigeration effect by using the latent heat of evaporation of the refrigerant to exchange heat with the material to be cooled. Throughout the cycle, the air conditioner regulates the temperature of the interior space.

The outdoor unit of the air conditioner includes the part of the compressor, outdoor heat exchanger and outdoor fan in the refrigeration cycle system; the indoor unit of the air conditioner includes the part of the indoor heat exchanger and the indoor fan; throttling devices (such as capillary tubes or electronic expansion valves) It can be set in the indoor unit or outdoor unit.

The indoor and outdoor heat exchangers can be used as condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner performs a heating mode, and when the indoor heat exchanger is used as an evaporator, the air conditioner performs a cooling mode.

Among them, the conversion of the indoor heat exchanger and the outdoor heat exchanger to be used as a condenser or an evaporator is generally realized by using a four-way valve. For details, refer to the settings of a conventional air conditioner, and details will not be described here.

The refrigeration working principle of the air conditioner is: the compressor works so that the indoor heat exchanger (in the indoor unit, the evaporator at this time) is in an ultra-low pressure state, the liquid refrigerant in the indoor heat exchanger quickly evaporates and absorbs heat, and the indoor fan blows out After cooling down by the indoor heat exchanger coil, the wind turns into cold air and blows it indoors. After the evaporated refrigerant is pressurized by the compressor, the high pressure in the outdoor heat exchanger (in the outdoor unit, it is the condenser at this time) It condenses into a liquid state in the environment, releases heat, and dissipates the heat into the atmosphere through the outdoor fan, so that the cycle achieves the cooling effect.

The heating working principle of the air conditioner is: the gaseous refrigerant is pressurized by the compressor to become a high-temperature and high-pressure gas, enters the indoor heat exchanger (in this case, the condenser), condenses and liquefies, releases heat, and becomes a liquid, and at the same time heats the indoor air, thereby To achieve the purpose of increasing the indoor temperature. The liquid refrigerant is decompressed by the throttling device, enters the outdoor heat exchanger (at this time, the evaporator), evaporates and gasifies, absorbs heat, and becomes a gas, and at the same time absorbs the heat of the outdoor air (the outdoor air becomes colder), and becomes a gaseous refrigerant. Enter the compressor again to start the next cycle.

An embodiment of the present disclosure discloses a multi-connected air conditioner. Referring to FIG. 3 , its heat exchange system includes a compressor 1 connected through pipelines, a gas-liquid separator 2, a four-way reversing valve 3, an outdoor heat exchanger 4 and a plurality of The indoor heat exchanger 5 arranged in parallel also includes an outdoor fan 6, an indoor fan 7, an outdoor unit expansion valve 8, an indoor unit expansion valve 9, a liquid side stop valve 10, a gas side stop valve 11, and the like.

The multi-connected air conditioner also includes a refrigerant charging device, a storage unit and a processing unit.

The refrigerant charging device is configured to charge refrigerant into the heat exchange system, so that the heat exchange pipeline has an appropriate amount of refrigerant to ensure the best performance of the air conditioning system.

The embodiments of the present disclosure focus on how to realize the automatic charging of the optimal amount of refrigerant for the heat exchange system by the refrigerant charging device.

In view of the fact that the subcooling degree of the condenser outlet is sensitive to the change of the amount of refrigerant, if the amount of refrigerant is large, the degree of subcooling at the outlet of the condenser becomes larger; when the amount of refrigerant is small, the degree of subcooling at the outlet of the condenser becomes smaller. The relationship between the degree of subcooling and the amount of refrigerant is shown in 1.

Based on this, the embodiment of the present disclosure indirectly obtains the charging amount of the refrigerant by monitoring the change of the subcooling degree at the outlet of the condenser during the charging process of the refrigerant, so as to optimize the charging amount of the refrigerant and ensure the optimum performance of the air conditioning system. good running condition.

Specifically, the internal refrigerant volume VO of the outdoor unit and the internal refrigerant volume VI of each indoor unit are stored in the storage unit.

Before the refrigerant is charged, the processing unit will read the data VO and VI stored in the storage unit, and calculate the ratio VI/VO of the two. The processing unit determines the target subcooling degree SCO (value range is 1-25) at the outlet of the outdoor heat exchanger (used as a condenser) according to the ratio VI/VO. The relationship between the target subcooling SCO and the ratio VI/VO is shown in Figure 2.

Then use the refrigerant charging device to charge the refrigerant. During the refrigerant charging process, the multi-connected air conditioner operates in cooling mode. At this time, the outdoor heat exchanger acts as a condenser, and the multi-connected air conditioner monitors the outlet Te of the outdoor heat exchanger 4 in real time. The supercooling degree SC, when SC≥SCO, stop refrigerant charging.

Wherein, SC=Tdc−Te, Tdc is the saturation temperature corresponding to the system high pressure Pd, and Te is the outlet temperature of the outdoor heat exchanger 4 .

The refrigerant charging method of the multi-connected air conditioner obtains the ratio VI/VO of the two through the pre-stored VI and VO, and then obtains the target subcooling degree SCO of the system through the ratio VI/VO, and controls the refrigerant charging amount accordingly. And based on the relationship between the degree of subcooling and the amount of refrigerant, the optimal amount of refrigerant can be charged.

Combined with Figure 2, the internal volume of indoor and outdoor units is different, considering the operating performance and reliability of the system during heating, and the optimal target subcooling degree SCO during cooling is different. When the ratio VI/VO is small, in order to ensure that the high pressure of the indoor unit is not too high (poor reliability), the target subcooling degree SCO during cooling should be as small as possible; when the ratio VI/VO is large, in order to ensure that the indoor unit high pressure is not too low (poor capacity) ), the target subcooling SCO should be as large as possible.

The refrigerant charging device includes a refrigerant tank 14 and a refrigerant charging pipeline, and the refrigerant charging pipeline is connected to the pipeline between the compressor 1 and the gas-liquid separator 2 .

The refrigerant charging pipeline includes a hard pipeline 16 and a hose pipeline 15. The hard pipeline 16 and the hose pipeline 15 are connected through a joint 17. One end of the hard pipeline 16 is connected to the heat exchange pipeline, and one end of the hose pipeline 15 is connected to the The refrigerant tank 14 is connected. A regulating valve 13 is provided on the hose line 15 , and the hose line 15 is connected to the hard line 16 through a joint 17 when the refrigerant is charged, and the regulating valve 13 can be opened.

During the refrigerant charging process, the multi-split air conditioner judges whether the refrigerant tank 14 needs to be replaced according to the increment ΔSC of the subcooling degree SC at the outlet of the outdoor heat exchanger 4 within a unit time (for example, 2 minutes).

When the increment ΔSC is less than the system setting value, the system issues an instruction to replace the refrigerant tank 14, cuts off the charging pipeline, replaces a new refrigerant tank, and then reopens the charging pipeline.

When the increment △SC is greater than the system setting value, continue to charge the refrigerant.

For the setting on the filling pipeline (specifically, the hard pipeline 16), three specific implementation methods are given as examples.

The first one is to install an electronic expansion valve 12 on the refrigerant charging pipeline, as shown in FIG. 3 .

In the second type, a capillary 18 and a solenoid valve 19 are arranged on the refrigerant charging pipeline, as shown in FIG. 4 . This solution only uses the capillary tube 18 to perform fixed regulation of the refrigerant charging flow rate to improve system reliability, but the charging speed under some working conditions will be slightly worse than that of the first solution. The solenoid valve 19 is opened when the refrigerant charging starts, and is closed when the charging is completed.

The third type is that only the capillary 18 is arranged on the refrigerant charging pipeline, refer to FIG. 5 . This solution cannot realize the automatic start and close of refrigerant charging through the solenoid valve. When the charging starts, the regulating valve 13 needs to be opened manually according to the prompt, and the regulating valve 13 needs to be manually closed according to the prompt after the charging is completed.

When the solution of the electronic expansion valve is adopted, the control of the electronic expansion valve 12 refers to FIG. 7 .

After the refrigerant automatic charging starts, the electronic expansion valve 12 has an initial value EVCO;

During the refrigerant charging process, if the suction superheat Tssh is greater than a certain value of the system preset suction superheat Tssh0, the opening of the electronic expansion valve 12 increases;

If the suction superheat Tssh is less than the system preset suction superheat Tssh0 certain value, the opening of the electronic expansion valve 12 decreases;

Until EVC=EVCmin, EVCmin≥0PLS;

Where, Tssh=Ts-Tsc, Ts is the suction temperature of the compressor, and Tsc is the saturation temperature corresponding to the system low pressure Ps.

Wherein, in conjunction with Fig. 7 .

EVC(N): EVC opening at step N, PLS;

EVC(N+1): EVC opening at step N+1, PLS;

EVC0: The system presets the initial value of EVC, PLS, determined by experiments, and the values are different for different capacity units;

Tssh: suction superheat, K;

Tssh0: target value of suction superheat, value range (0-20), preferably (1-5), K;

g: constant, g>0, preferably the value range of g is (0, 5), K;

h: constant, h<0, preferably the value range of h is (-5, 0), K.

Refer to FIG. 6 for the automatic charging process of the multi-connected air conditioner refrigerant.

Before the refrigerant is automatically charged, connect the refrigerant charging device to the heat exchange pipeline, and perform air discharge operation on the refrigerant charging pipeline, fully open the regulating valve 13 before charging, and pre-charge a proper amount of refrigerant to ensure runnable;

After completing the automatic charging preparation, select the refrigerant automatic charging operation mode through the main control board or the air conditioning controller;

After the charging mode selection is completed, the ambient temperature will be judged. When the outdoor ambient temperature and indoor ambient temperature reach the system setting range (for example, the outdoor ambient temperature is -10-43°C, and the indoor ambient temperature is 10-35°C), the system will Start to run, the four-way reversing valve 3 is opened, and the air conditioner operates in cooling mode;

After the system starts up, it begins to carry out stable operation control. The judgment of this process is based on the variation of compressor 1 discharge temperature Td within a certain period of time. Specifically, after compressor 1 runs for a period of time (such as 10 minutes), monitor The variation △Td of the exhaust gas temperature Td within a set time period (for example, 1min). If the variation △Td is within the range set by the system, it is determined that the multi-split air conditioner is running stably, and refrigerant charging can be performed;

After judging that the system is running stably, the processing unit reads the data VO and VI stored in the storage unit, and calculates the ratio VI/VO of the two, and the processing unit determines the target subcooling degree at the outlet of the outdoor heat exchanger according to the ratio VI/VO SCO, start refrigerant charging.

In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in an appropriate manner.

The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily imagined by those skilled in the art within the technical scope disclosed in the present invention shall be covered. Within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (9)

A multi-connected air conditioner, comprising: Heat exchange system, including a compressor connected through pipelines, a gas-liquid separator, a four-way reversing valve, an outdoor heat exchanger, and multiple indoor heat exchangers arranged in parallel; A refrigerant charging device configured to charge refrigerant into the heat exchange system; The storage unit stores the internal refrigerant volume VO of the outdoor unit and the internal refrigerant volume VI of each indoor unit; A processing unit configured to read the data VO and VI stored in the storage unit, calculate the ratio VI/VO of the two, and determine the target subcooling degree at the outlet of the outdoor heat exchanger according to the ratio VI/VO SCO; Wherein, during the refrigerant charging process of the refrigerant charging device, the multi-split air conditioner monitors the subcooling degree SC at the outlet of the outdoor heat exchanger in real time, and stops refrigerant charging when SC≥SCO. The multi-connected air conditioner according to claim 1, The refrigerant charging device includes a refrigerant tank and a refrigerant charging pipeline, and the refrigerant charging pipeline is connected to the pipeline between the compressor and the gas-liquid separator; During the refrigerant charging process, the multi-split air conditioner judges whether the refrigerant tank needs to be replaced according to the increment ΔSC of the subcooling degree SC at the outlet of the outdoor heat exchanger per unit time; When the increase ΔSC is less than the system setting value, the system issues an instruction to replace the refrigerant tank; When the increasing amount ΔSC is greater than the system setting value, the refrigerant charging will continue. According to the multi-connected air conditioner according to claim 2, An electronic expansion valve is arranged on the refrigerant charging pipeline. According to the multi-connected air conditioner according to claim 3, The electronic expansion valve has an initial value EVCO; During the refrigerant charging process, if the suction superheat Tssh is greater than the system preset suction superheat Tssh0 certain value, the opening of the electronic expansion valve increases; If the suction superheat Tssh is less than a certain value of the system preset suction superheat Tssh, the opening of the electronic expansion valve decreases; Until EVC=EVCmin, EVCmin≥0PLS; Wherein, Tssh=Ts-Tsc, Ts is the suction temperature of the compressor, and Tsc is the saturation temperature corresponding to the system low pressure Ps. According to the multi-connected air conditioner according to claim 2, The refrigerant charging pipeline is provided with a capillary and a solenoid valve. According to the multi-connected air conditioner according to claim 2, A capillary is arranged on the refrigerant charging pipeline. According to the multi-connected air conditioner according to claim 2, A regulating valve is provided on the refrigerant charging pipeline. The multi-connected air conditioner according to any one of claims 1 to 7, The ambient temperature is judged before refrigerant charging, and when the outdoor ambient temperature and indoor ambient temperature reach the system setting range, the multi-connected air conditioner operates in cooling mode to prepare for refrigerant charging. According to the multi-connected air conditioner according to claim 8, When the multi-connected air conditioner is running in the cooling mode, it monitors the variation ΔTd of the discharge temperature Td of the compressor within a set period of time. If the variation ΔTd is within the system setting range, When the multi-connected air conditioner is running stably, refrigerant charging is performed.

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