JP5885944B2 - Multi-type air conditioner and control method of multi-type air conditioner - Google Patents

Description

  The present invention relates to a multi-type air conditioner in which a plurality of indoor unit units are connected in parallel to one outdoor unit.

Conventionally, in an air conditioner, operation is performed by connecting a plurality of indoor unit units in parallel to one outdoor unit. Such an air conditioner is called, for example, a multi-type air conditioner (hereinafter referred to as “multi air conditioner”).
In a conventional multi-air conditioner, each indoor unit has an electronic expansion valve (EEV), and by adjusting the throttle (opening) of each electronic expansion valve, an appropriate operating point or refrigerant of each indoor unit is obtained. The distribution amount is controlled. In such a multi-air conditioner, an operating point of the whole apparatus installed between the receiver and the outdoor heat exchanger, which is installed between the receiver and the outdoor heat exchanger downstream of the outdoor heat exchanger that functions as a condenser during cooling operation. And an outdoor unit electronic expansion valve for adjusting the air pressure.

Moreover, the following prior art is known about refrigerant | coolant amount control of a multi-type air conditioning apparatus.
The multi-room air conditioner disclosed in the following Patent Document 1 keeps the refrigerant circulation amount appropriately according to the number of operating indoor units and the refrigerant discharge temperature, and prevents an increase in discharge temperature and insufficient capacity. It is.

In the refrigeration cycle disclosed in Patent Document 2 below, even when a refrigeration oil that is weakly soluble in a refrigerant is used, the refrigeration oil accumulates inside the refrigeration cycle, leading to oil exhaustion of the compressor. It is possible to prevent the occurrence of a large amount of liquid back to the compressor even if the accumulator is eliminated.
The operation method of the multi-chamber air conditioner disclosed in the following Patent Document 3 prevents the liquid refrigerant from accumulating in the receiver during the cooling operation, ensures the refrigerant circulation amount in the refrigeration cycle, and is in a state of insufficient capacity. This makes it possible to operate properly.

JP 2002-156166 A Japanese Patent No. 3671850 JP 2010-210164 A

By the way, in the conventional multi-type air conditioner, when the number of indoor unit units increases, for example, when six indoor unit units are installed and operated in differently sized rooms, The difference in the amount of refrigerant required during the heating operation (necessary cooling / heating refrigerant difference) increases.
For this reason, for example, in a situation where all the indoor unit units are in operation during cooling operation, the liquid refrigerant condensed in the outdoor heat exchanger is stored in the receiver, and the amount of refrigerant circulating in the refrigerant circuit decreases, resulting in insufficient refrigerant. There is concern about becoming.

From such a background, especially during the cooling operation of the multi-type air conditioner, it is possible to prevent a shortage of refrigerant especially during the cooling operation of all the indoor unit units, and to secure the necessary refrigerant amount in each indoor unit. It is desirable to be able to perform the desired cooling operation.
The present invention has been made in order to solve the above-described problems, and an object of the present invention is to prevent liquid refrigerant from accumulating in the receiver during the cooling operation of all the indoor unit units, resulting in insufficient refrigerant. Another object of the present invention is to provide a multi-type air conditioner in which each indoor unit can perform a desired cooling operation.

In order to solve the above problems, the present invention employs the following means.
A multi-type air conditioner according to the present invention includes an outdoor unit configured to include a variable power compressor, an outdoor heat exchanger, and a four-way valve, an indoor heat exchanger, and an electronic expansion valve. A multi-type air conditioner comprising a plurality of indoor unit units connected in parallel to a unit, and a control unit that performs various operation controls of the outdoor unit and the indoor unit, A receiver installed on the downstream side of the outdoor heat exchanger that sometimes functions as a condenser, and an outdoor unit electronic expansion valve installed between the receiver and the outdoor heat exchanger. The control unit that controls the opening degree during cooling operation is a total number cooling opening degree that reduces the opening degree of the outdoor unit electronic expansion valve to a predetermined value according to the outdoor heat exchanger tube sensor temperature during the total number operation of the indoor unit. Provide control mode , At least one of said plurality of indoor units is, when the heating operation or when stopping the cooling operation, characterized in that a fully open or substantially fully open the opening of the outdoor unit electronic expansion valve Is.

According to such a multi-type air conditioner of the present invention, a receiver installed on the downstream side of an outdoor heat exchanger that functions as a condenser during cooling operation, and an outdoor installed between the receiver and the outdoor heat exchanger An electronic expansion valve for the outdoor unit, and the controller for controlling the opening degree of the outdoor electronic expansion valve during the cooling operation is configured to control the outdoor electronic expansion valve according to the temperature of the outdoor heat exchanger tube sensor during the entire cooling operation of the indoor unit. Is equipped with an all-cooling opening control mode that reduces the opening of the outdoor unit to a predetermined value, so that when the indoor unit is fully cooled, the liquid refrigerant condensed in the outdoor heat exchanger has a small opening It becomes difficult to pass.
As a result, the liquid refrigerant condensed in the outdoor heat exchanger is unlikely to flow into the receiver on the downstream side of the outdoor unit electronic expansion valve having a large flow path resistance, so that the liquid refrigerant accumulates in the receiver and becomes excess refrigerant. The refrigerant circuit can be prevented from running out of refrigerant.

In order to implement (ON) the all-cooling opening degree control mode described above, the variable power compressor is ON, the operation mode is selected to be cooling, and all the indoor unit units are operated. And the condition that the outdoor heat exchanger liquid sensor temperature Th is equal to or lower than a predetermined implementation temperature must be satisfied.
Moreover, in order to cancel | release (OFF) the whole number cooling opening degree control mode mentioned above, there exists a change in the operating number of indoor unit units, there exists a change in the operation mode of air conditioning, and outdoor heat exchanger liquid sensor temperature It is necessary to satisfy at least one of the conditions for Th to rise to a predetermined release set temperature.
As for the set temperature (execution set temperature and release set temperature) of the outdoor heat exchanger tube sensor temperature Th for turning ON / OFF the all-cooling opening degree control mode, the all-cooling opening degree control mode is not frequently executed or canceled. Therefore, it is preferable to provide a hysteresis of about 1 ° C., for example.
In the above invention, when the outdoor heat exchanger tube sensor temperature is equal to or lower than a predetermined implementation set temperature, the controller controls the opening degree of the outdoor unit electronic expansion valve from a fully open state or a substantially fully open state to a predetermined value. When the outdoor heat exchanger tube sensor temperature rises to a predetermined preset release temperature, the outdoor unit electronic expansion valve is fully opened or substantially fully opened.
The control method for a multi-type air conditioner according to the present invention includes an outdoor unit configured to include a variable power compressor, an outdoor heat exchanger, and a four-way valve, an indoor heat exchanger, and an electronic expansion valve. A plurality of indoor unit units that are connected in parallel with the outdoor unit, a control unit that performs various operation controls of the outdoor unit and the indoor unit, and the condenser that functions as a condenser during cooling operation. A control method for a multi-type air conditioner, comprising: a receiver installed downstream of an outdoor heat exchanger; and an outdoor unit electronic expansion valve installed between the receiver and the outdoor heat exchanger, The control unit that controls the opening degree of the outdoor unit electronic expansion valve during cooling operation sets the opening degree of the outdoor unit electronic expansion valve to a predetermined value according to the outdoor heat exchanger tube sensor temperature when all the indoor unit units are operated. All the numbers are squeezed to cold The step of setting the opening control mode, and the control unit sets the opening of the outdoor unit electronic expansion valve when at least one of the plurality of indoor unit units stops the cooling operation or performs the heating operation. And a step of making it fully open or substantially fully open.

  According to the above-described present invention, when the multi-type air conditioner is in the cooling operation, when the cooling operation is performed with the total number of indoor unit units, the opening degree of the outdoor electronic expansion valve depends on the outdoor heat exchanger tube sensor temperature. Since the all-cooling cooling opening degree control mode for reducing the pressure to a predetermined value is performed, it is possible to prevent the liquid refrigerant from becoming surplus refrigerant and collecting in the receiver. For this reason, the liquid refrigerant remains on the outdoor heat exchanger side, and therefore, it is possible to prevent a shortage of the refrigerant amount circulating in the refrigerant circuit and to reliably distribute the necessary refrigerant amount to each indoor unit. Therefore, a desired cooling operation can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a systematic diagram which shows one Embodiment of the multi-type air conditioning apparatus (multi air conditioner) which concerns on this invention, and the structural example with six indoor unit units is shown. An example of hysteresis for turning ON / OFF the total number of cooling opening control modes for the outdoor heat exchanger tube sensor temperature Th, which is one of the conditions for performing the total number of cooling opening control modes of the outdoor unit electronic expansion valve during cooling operation It is explanatory drawing shown.

Hereinafter, an embodiment of a multi-type air conditioner (multi-air conditioner) according to the present invention will be described with reference to the drawings. The multi air conditioner described below is a configuration example in which six indoor unit units are connected in parallel, but the number of indoor unit units connected is not limited to six.
1 constitutes a closed circuit refrigeration cycle in which six indoor unit units 30A to 30F are connected in parallel to one outdoor unit 10. This multi air conditioner AC includes a control unit 50 that performs various operation controls of the outdoor unit 10 and the indoor unit 30A to 30F, and by selectively switching the flow direction of the refrigerant circulating in the refrigeration cycle, the cooling operation and the heating operation are performed. Can be done.
In addition, the arrow of FIG. 1 has shown the flow direction of the refrigerant | coolant at the time of air_conditionaing | cooling operation, In the following description, when it is not necessary to distinguish six indoor unit 30A-30F and its related equipment, A to F are omitted and referred to as “indoor unit 30”.

  The outdoor unit 10 includes, for example, a variable power compressor (hereinafter referred to as “compressor”) 11 driven by an inverter-controlled electric motor, and an outdoor heat exchanger 12 that performs heat exchange between the refrigerant and the outside air. And a four-way valve 13 for selectively performing a cooling operation and a heating operation by selectively switching the circulation direction of the refrigerant supplied from the compressor 11. The compressor 11 and the four-way valve 13 are configured to receive the control signal from the control unit 50 and to control the rotation speed and the refrigerant circulation direction.

A discharge temperature sensor 14 for detecting a refrigerant discharge pipe sensor temperature Td is provided on the discharge side of the compressor 11, and a suction temperature sensor 15 for detecting a refrigerant suction pipe sensor temperature Ts is provided on the suction side of the compressor 11. Is provided. In addition, an outdoor heat exchanger temperature sensor 16 that detects the outdoor heat exchanger liquid pipe sensor temperature Th is provided at an appropriate place of the outdoor heat exchanger 12.
The temperature detection values (Td, Ts, Th) detected by the discharge temperature sensor 14, the suction temperature sensor 15, and the outdoor heat exchange temperature sensor 16 are input to the control unit 50 and used for various operation controls.

The indoor unit units 30A to 30F are each provided with indoor heat exchangers 31A to 31F, and the indoor unit units 30A to 30F are branched from the headers 32A and 32B to the refrigerant pipes 33A to 33F connected in parallel. Is provided.
In the refrigerant pipes 33A to 33F, electronic expansion valves 34A to 34F and opening / closing valves 35A to 35F are provided on both sides of the indoor unit 30A to 30F, respectively. In the illustrated configuration example, the electronic expansion valves 34A to 34F are installed on the upstream side of the indoor unit 30A to 30F in the refrigerant flow direction during the cooling operation, and the on-off valves 35A to 35F are installed on the downstream side.

In this case, as the on-off valves 35A to 35F, those that can be operated remotely, such as electromagnetic valves, are used. Therefore, the on-off valves 35A to 35F are in accordance with the operation / stop state of the indoor unit 30. In response to a control signal from the control unit 50, it opens and closes. Further, the electronic expansion valves 34 </ b> A to 34 </ b> F are similarly controlled by receiving individual control signals from the control unit 50.
In addition, indoor heat exchange temperature sensors 36A to 36F that detect an indoor heat exchange liquid tube sensor temperature TR for each indoor unit are provided at appropriate positions of the indoor unit 30A to 30F. Any detected value of the indoor heat exchange liquid tube sensor temperature TR detected by the indoor heat exchange temperature sensors 36A to 36F is input to the control unit 50 and used for various operation controls.

  And the multi air conditioner AC of this embodiment is equipped with the receiver 20 and the outdoor unit electronic expansion valve 21 in the downstream of the outdoor heat exchanger 12 which functions as a condenser at the time of air_conditionaing | cooling operation. Since the outdoor unit electronic expansion valve 21 in this case is disposed between the receiver 20 and the outdoor heat exchanger 12, the receiver 20 is downstream of the outdoor unit electronic expansion valve 21 in the refrigerant flow direction during the cooling operation. Become the side.

The receiver 20 is a container having a function of holding excess refrigerant during heating operation and cooling operation. That is, during the cooling operation, the receiver 20 is a container for temporarily storing the liquid refrigerant liquefied by the outdoor heat exchanger 12 functioning as a condenser.
The outdoor unit electronic expansion valve 21 is provided to adjust the operating point of the entire system of the multi air conditioner AC, separately from the electronic expansion valve 34 for each indoor unit 30 described above. The outdoor electronic expansion valve 21 receives a control signal output from the control unit 50 and controls the throttle amount (opening adjustment), for example, a receiver disposed on the downstream side in the refrigerant flow direction during cooling operation. 20 has a function of preventing liquid refrigerant from accumulating.

  That is, the opening degree control of the outdoor unit electronic expansion valve 21 described above includes preventing the refrigerant from becoming insufficient even when the cooling operation is performed with all the indoor unit units 30 during the cooling operation. In other words, the control unit 50 that performs the opening control during the cooling operation of the outdoor unit electronic expansion valve 21 is performed according to the outdoor heat exchanger tube sensor temperature Th during the total cooling operation of the indoor unit 30. Is provided with an all-cooling cooling opening control mode in which the opening is reduced to a predetermined value.

Hereinafter, the above-described exhaust cooling control mode will be described.
In order to implement (ON) the all-cooling opening degree control mode, the compressor 11 is ON, the operation mode of the multi air conditioner AC is selected to be cooling, and all the indoor unit units 30 are cooled. It is necessary to satisfy all the conditions that the outdoor heat exchange liquid tube sensor temperature Th is equal to or lower than a predetermined implementation temperature. That is, in the control unit 50, the outdoor heat exchange liquid detected by the outdoor heat exchange temperature sensor 16 in the operation state in which the multi air conditioner AC performs the cooling operation and all the indoor unit units 30 perform the cooling operation. For example, as shown in FIG. 2, when the pipe sensor temperature Th is a low temperature equal to or lower than a predetermined execution set temperature t1, it is determined that all the conditions are satisfied, and the all-cooling opening degree control mode is executed.

When the all-cooling opening degree control mode is executed, the control unit 50 reduces the opening degree of the outdoor unit electronic expansion valve 21, that is, the opening degree of the outdoor unit electronic expansion valve 21 in the fully open or substantially fully open state. For example, the control signal is output so as to reduce the opening to about one third. In the normal cooling operation state, the opening degree of the outdoor unit electronic expansion valve 21 is fully opened or substantially fully opened.
When the opening degree of the outdoor unit electronic expansion valve 21 is reduced in this way, the liquid refrigerant condensed in the outdoor heat exchanger 12 increases the flow resistance of the outdoor unit electronic expansion valve 21 having a small opening degree. It becomes difficult to flow to the downstream side of the expansion valve 21. As a result, the liquid refrigerant condensed in the outdoor heat exchanger 12 is accumulated in the outdoor heat exchanger 12 on the upstream side of the outdoor unit electronic expansion valve 21 having a large flow path resistance, so that the liquid refrigerant is an excess refrigerant. Therefore, it is possible to prevent the amount of refrigerant circulating in the refrigerant circuit from being insufficient.

  Further, the above-described all-cooling opening degree control mode has a preset setting in which the number of operating units of the indoor unit 30 is changed, the operating mode of the air conditioning is changed, and the outdoor heat exchanger liquid sensor temperature Th is set in advance. The condition for increasing to the temperature t2 is canceled (OFF) when at least one of the conditions is satisfied. That is, when the operation of at least one indoor unit 30 is stopped, when the operation mode of air conditioning is changed from the cooling operation to the heating operation, or when the outdoor heat exchanger tube temperature Th is a predetermined release set temperature t2. When it becomes above, all-cooling opening degree control mode is cancelled | released and the outdoor unit electronic expansion valve 21 is made into the state of full open or substantially fully open.

  By the way, with respect to the implementation set temperature t1 and the release set temperature t2 described above, a hysteresis of about 1 ° C., for example, is provided in order to prevent the exhaust cooling control mode from being frequently turned ON / OFF. As an example of the set temperatures of the implementation set temperature t1 and the release set temperature t2, for example, there is a setting of providing a hysteresis of 1 ° C. with t1 = 38 ° C. and t2 = 39 ° C.

  Thus, the multi air conditioner AC of the present embodiment is installed between the receiver 20 installed on the downstream side of the outdoor heat exchanger 12 that functions as a condenser during cooling operation, and between the receiver 20 and the outdoor heat exchanger 12. The control unit 50 that includes the outdoor unit electronic expansion valve 21 and controls the opening degree of the outdoor unit electronic expansion valve 21 during the cooling operation depends on the outdoor heat exchanger tube sensor temperature Th when all the indoor unit units 30 are operated. Since the all-cooling opening degree control mode for reducing the opening degree of the outdoor electronic expansion valve 21 to a predetermined value is provided, the liquid refrigerant condensed in the outdoor heat exchanger 12 is opened when the indoor unit unit 30 is fully-cooled. Therefore, it is difficult for the outdoor unit electronic expansion valve 21 to pass through, and therefore, it is difficult to accumulate in the receiver 20 as surplus refrigerant.

As a result, the multi air conditioner AC of the present embodiment has a predetermined opening degree of the outdoor electronic expansion valve 21 according to the outdoor heat exchanger tube sensor temperature Th even if the cooling operation is performed with all the indoor unit units 30 during the cooling operation. Since the all-cooling opening degree control mode is reduced to the value, the liquid refrigerant remains on the outdoor heat exchanger side 12 without accumulating in the receiver 20. Therefore, by implementing the all-cooling opening degree control mode, it is possible to prevent a shortage of the amount of refrigerant circulating in the refrigerant circuit, and to reliably distribute the necessary amount of refrigerant to each indoor unit 30 and to perform a desired cooling operation.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary, it can change suitably.

10 outdoor unit 11 variable power compressor (compressor)
12 Outdoor Heat Exchanger 13 Four-way Valve 14 Discharge Temperature Sensor 15 Suction Temperature Sensor 16 Outdoor Heat Exchange Temperature Sensor 20 Receiver 21 Outdoor Unit Electronic Expansion Valve 30 (30A to 30F) Indoor Unit Unit 31 (31A to 31F) Indoor Heat Exchanger 32A , 32B Header 33 (33A to 33F) Refrigerant piping 34 (34A to 34F) Electronic expansion valve 35 (35A to 35F) On-off valve 36 (36A to 36F) Indoor heat exchanger temperature sensor 50 Control unit AC Multi-type air conditioner (multi Air conditioner)

Claims (4)

An outdoor unit configured to include a variable power compressor, an outdoor heat exchanger, and a four-way valve, and a plurality of units including an indoor heat exchanger and an electronic expansion valve and connected in parallel to the outdoor unit. A multi-type air conditioner comprising: an indoor unit of the control unit; and a control unit that performs various operation controls of the outdoor unit and the indoor unit.
A receiver installed on the downstream side of the outdoor heat exchanger that functions as a condenser during cooling operation, and an outdoor unit electronic expansion valve installed between the receiver and the outdoor heat exchanger,
The control unit that controls the opening degree of the outdoor unit electronic expansion valve during cooling operation determines the opening degree of the outdoor unit electronic expansion valve according to the outdoor heat exchanger tube sensor temperature when all the indoor unit units are operated. A total number of cooling unit opening degree control modes for reducing the value to a value, and when at least one of the plurality of indoor unit units stops cooling operation or performs heating operation, the opening degree of the outdoor unit electronic expansion valve is fully opened or A multi-type air conditioner characterized by being in a substantially fully open state .   The control unit reduces the opening degree of the outdoor electronic expansion valve from a fully open state or a substantially fully open state to a predetermined value when the outdoor heat exchanger liquid sensor temperature is equal to or lower than a predetermined implementation temperature. 2. The multi-type air according to claim 1, wherein when the outdoor heat exchange liquid tube sensor temperature rises to a predetermined release set temperature, the outdoor unit electronic expansion valve is fully opened or substantially fully opened. Harmony device.   An outdoor unit configured to include a variable power compressor, an outdoor heat exchanger, and a four-way valve, and a plurality of units including an indoor heat exchanger and an electronic expansion valve and connected in parallel to the outdoor unit. An indoor unit, a control unit that controls various operations of the outdoor unit and the indoor unit, a receiver installed on the downstream side of the outdoor heat exchanger that functions as a condenser during cooling operation, and the receiver A control method of a multi-type air conditioner comprising an outdoor unit electronic expansion valve installed between the outdoor heat exchanger,
  The control unit that controls the opening degree of the outdoor unit electronic expansion valve during cooling operation determines the opening degree of the outdoor unit electronic expansion valve according to the outdoor heat exchanger tube sensor temperature when all the indoor unit units are operated. A step of setting the total number of cooling units to a value, and the control unit includes the electronic expansion of the outdoor unit when at least one of the plurality of indoor unit units stops the cooling operation or performs the heating operation. And a step of bringing the valve opening to a fully open or substantially fully open state.   The control unit reduces the opening degree of the outdoor electronic expansion valve from a fully open state or a substantially fully open state to a predetermined value when the outdoor heat exchanger liquid sensor temperature is equal to or lower than a predetermined implementation temperature. 4. The multi-type air according to claim 3, wherein when the outdoor heat exchange liquid tube sensor temperature rises to a predetermined preset release temperature, the outdoor unit electronic expansion valve is fully opened or substantially fully opened. Harmonic device control method.

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