JP2971201B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner comprising an outdoor unit and a plurality of indoor units and having a refrigerant heater.

[0002]

2. Description of the Related Art Generally, in a multi-type air conditioner comprising an outdoor unit and a plurality of indoor units and provided with a refrigerant heater, a two-way valve is provided in a refrigerant flow path to each indoor unit. The flow of the refrigerant to each indoor unit is controlled by opening and closing the direction valve. For example, if the number of indoor units is two and both are operated,
Open each two-way valve and allow refrigerant to flow to each indoor unit.

When the operation of one indoor unit is stopped halfway, the two-way valve corresponding to the indoor unit is closed to shut off the flow of the refrigerant. Thereafter, when restarting the operation of the stopped indoor unit, the corresponding two-way valve is opened.

[0004]

In the above air conditioner, when one of the indoor units is operated and the other is stopped, the two-way valve corresponding to the stopped indoor unit is operated. A large pressure difference occurs at both ends.

For this reason, when the two-way valve is opened when the operation of the stopped indoor unit is restarted, a large load is imposed on the two-way valve due to the flow of the refrigerant at a time, which adversely affects the life of the two-way valve. In addition, there is a problem that a loud refrigerant noise is generated when the refrigerant flows at one time, which causes discomfort to residents. The present invention has been made in view of the above circumstances,

[0006] An object of claims 1 and 2 is to reduce the load on the two-way valve when the two-way valve is opened due to an increase in the number of operating indoor units. Accordingly, it is an object of the present invention to provide a highly reliable air conditioner capable of improving the life of a two-way valve and preventing generation of loud refrigerant noise and eliminating discomfort.

[0007]

According to a first aspect of the present invention, there is provided an air conditioner comprising: an outdoor unit having a compressor, a four-way valve, and an outdoor heat exchanger; a plurality of indoor units each having an indoor heat exchanger; Machine, four-way valve, outdoor heat exchanger, pressure reducer,
A refrigeration cycle communicating with a parallel circuit of each indoor heat exchanger;
A flow control valve provided in communication with each of the gas side pipes between each of the indoor heat exchangers and the four-way valve, and a four-way valve side of each of the gas side pipes with respect to the communication position of the flow rate control valve. A two-way valve provided at each position, a refrigerant heater provided from a communication portion between the outdoor heat exchanger and the decompressor to a suction port side of the compressor, and a four-way refrigerant flowing from the compressor. A valve, an outdoor heat exchanger, a decompressor, a means for flowing through each indoor heat exchanger and each two-way valve to execute cooling operation, and a four-way valve, each two-way valve, and a refrigerant discharged from the compressor. Means for performing a flowing heating operation through an indoor heat exchanger, a decompressor, and a refrigerant heater; and, during the heating operation, when opening the two-way valve corresponding to the increased indoor unit when the number of operating indoor units increases. Open the flow control valve, let the refrigerant flow downstream of the two-way valve, And a means of reducing pre-pressure differential across the-way valve.

According to a second aspect of the present invention, an air conditioner includes an outdoor unit having a compressor, a four-way valve, and an outdoor heat exchanger, a plurality of indoor units each having an indoor heat exchanger, the compressor, the four-way valve, and an outdoor unit. A refrigeration cycle that communicates a parallel circuit of a heat exchanger, a decompressor, and each indoor heat exchanger, and a flow control that is provided to communicate between gas side pipes between each of the indoor heat exchangers and the four-way valve. A valve, a two-way valve provided in each of the gas side pipes at a position on the four-way valve side of the communication position of the flow rate regulating valve, and a suction port of the compressor from a communication portion between the outdoor heat exchanger and the pressure reducer. A refrigerant heater provided in communication with the compressor and a refrigerant discharged from the compressor are passed through a four-way valve, an outdoor heat exchanger, a decompressor, each indoor heat exchanger, and each two-way valve to perform a cooling operation. And a four-way valve for discharging the refrigerant discharged from the compressor. Way valve, the indoor heat exchanger, a pressure reducer,
Means for flowing through the refrigerant heater to perform the heating operation; and, during the heating operation, open the two-way valve corresponding to the larger required capacity of each indoor unit among the respective two-way valves and open the two-way valve corresponding to the smaller one. Means for closing the direction valve, and means for controlling the opening degree of the flow control valve so that the temperature of the refrigerant flowing into each indoor heat exchanger has a predetermined relationship based on the required capacity of each indoor unit during the heating operation, Means for setting the flow control valve to a predetermined opening before the opening of the two-way valves when the operation state of each indoor unit changes during the heating operation.

[0009]

According to the air conditioner of the first aspect, when the number of operating indoor units increases during the heating operation, the flow control valve opens before the two-way valve corresponding to the increased indoor unit opens, and the two-way valve is opened. The refrigerant flows into the downstream side, and the pressure difference between before and after decreases.

In the air conditioner of the second aspect, when the operation state of the indoor unit changes during the heating operation, the flow regulating valve opens before each two-way valve opens, and the pressure difference before and after each two-way valve decreases. I do.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. This embodiment corresponds to the air conditioner of the first aspect. In FIG. 1, A is an outdoor unit,
B ₁ and B ₂ are indoor units, which constitute the next refrigeration cycle between these units.

An outdoor heat exchanger 3 is connected to a discharge port of the compressor 1 via a four-way valve 2. The outdoor heat exchanger 3 is connected to a forward check valve 4 and a pair of liquid side pipes W ₁ and W _2. The indoor heat exchangers 12 and 22 are connected via the.

The gas side pipes G ₁ ,
G ₂ , an accumulator 6 is connected via the four-way valve 2 and the check valve 5 in the forward direction, and the accumulator 6 is connected to the accumulator 6.
To the suction port of the compressor 1. The liquid side tubes W ₁ and W ₂
Electronic expansion valve (pulse motor valve; PMV)
11 and 21 are provided. An electronic flow control valve (pulse motor valve; PMV) 7 is provided between the gas side tubes G ₁ and G _{2 so} as to communicate with each other. In the gas side pipes G ₁ and G ₂ , two-way valves 13 and 23 are provided at positions on the four-way valve 2 side of the communication position of the flow control valve 7, respectively.

From the communicating portion between the check valve 4 connected to the outdoor heat exchanger 9 and the electronic expansion valves 11, 21 to the accumulator 6 on the suction port side of the compressor 1, via the two-way valve 8. A refrigerant heater 30 is provided in communication.

The refrigerant heater 30 includes a gas burner 31,
The gas burner 3 includes a combustion fan 32, a proportional valve 33, an igniter 34 and a flame detector 35, which will be described later, and the like.
The refrigerant is heated by the first combustion flame. An outdoor fan 9 is provided near the outdoor heat exchanger 3, and indoor fans 14 and 24 are provided near the indoor heat exchangers 12 and 22, respectively. The heat exchanger temperature sensors 15 and 25 are attached to the indoor heat exchangers 12 and 22, respectively. Respectively to the gas side pipe G _1, G ₂ mounting the refrigerant temperature sensor 16, 26.

In the communication portion between the check valve 4 and the electronic expansion valves 11 and 21, the refrigerant temperature sensor 4 is located at a position slightly closer to the electronic expansion valves 11 and 21 than the connection portion of the system of the refrigerant heater 30.
Attach 1. A refrigerant temperature sensor 42 is attached to a communicating part from the refrigerant heater 30 to the accumulator 6. The control circuit is shown in FIG. The outdoor unit A includes an outdoor control unit 50. The outdoor control unit 50 is composed of a microcomputer and its peripheral circuits, and controls the entire outdoor unit A.

The outdoor control unit 50 includes an electronic expansion valve 11,
21, flow regulating valve 7, proportional valve 33, igniter 34, flame detector 35, combustion fan motor 32M, four-way valve 2, outdoor fan motor 9M, refrigerant temperature sensors 16, 26, 41,
42, two-way valve 13, 28, 8 and inverter circuit 5
1 is connected.

The inverter circuit 51 includes a commercial AC power supply 52
Rectified, converted into an AC voltage having a predetermined frequency and level according to a command from the outdoor control unit 50, and output. This output is supplied as drive power to the compressor motor 1M. The indoor unit B ₁ represents comprises indoor control unit 60. Indoor control unit 60, a microcomputer and its peripheral circuits, and performs the control through the whole range of the indoor unit B _1.

The indoor controller 60 includes an indoor temperature sensor 6
1. The heat exchanger temperature sensor 15, the remote control type operation control unit (hereinafter abbreviated as remote control) 62, and the indoor fan motor 14M are connected. The indoor unit B ₂ is provided with a room controller 60. Indoor control unit 60, a microcomputer and its peripheral circuits, and performs the control through the whole range of the indoor unit B _2. The indoor controller 60 includes an indoor temperature sensor 61 and a heat exchanger temperature sensor 2.
5. Connect the remote control 62 and the indoor fan motor 24M. Then, the indoor control units 60 and 60 are connected to the outdoor control unit 50 via the power line ACL and the serial signal line SL, respectively. The indoor control units 60 have the following functional means (1) to (3). (1) Means for sending an operation mode command or set indoor temperature data by operating the remote controller 62 to the outdoor control unit 50 as a serial signal synchronized with the power supply voltage.

(2) Means for comparing the detected temperature of the indoor temperature sensor 61 with the set indoor temperature of the remote controller 62, and sending an operation request corresponding to the comparison result to the outdoor control unit 50 by a serial signal synchronized with the power supply voltage. (3) Means for sending the detected temperature data of the heat exchanger temperature sensors 15 and 25 to the outdoor control unit 50 as a serial signal synchronized with the power supply voltage. The outdoor control unit 50 performs the following (4) to (15)
Function means.

(4) Based on the cooling operation mode command from the indoor units B ₁ and B ₂ , the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the outdoor heat exchanger 3, the check valve 4, and the electronic expansion valve 1.
1,21, indoor heat exchangers 12,22, two-way valves 13,2
3, means for flowing through the four-way valve 2, the check valve 5, and the accumulator 6 to execute the cooling operation. (5) Means for controlling the capacity of the compressor 1 (= output frequency F of the inverter circuit 51) in accordance with the presence or absence of the operation request of the indoor units B ₁ and B ₂ during the cooling operation. (6) Means for opening and closing the two-way valves 13 and 23 according to the presence or absence of the operation request of the indoor units B ₁ and B ₂ during the cooling operation. (7) Means for fully closing the flow control valve 7 during the cooling operation.

(8) During the cooling operation, the indoor heat exchangers 12, 2
Means for detecting the degree of superheat of the refrigerant at 2 (= the difference between the detected temperatures of the heat exchanger temperature sensors 15, 25 and the detected temperatures of the refrigerant temperature sensors 16, 26). (9) Each of these refrigerant superheats has a constant value.
Means for controlling the degree of opening of the electronic expansion valves 11 and 21.

(10) Based on the heating operation mode command from the indoor units B ₁ and B ₂ , the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the two-way valves 13 and 23, the indoor heat exchanger 12 and
22, electronic expansion valves 11, 21, two-way valve 8, refrigerant heater 3
0, means for flowing through the accumulator 6 to perform the heating operation.

(11) During this heating operation, the capacity of the compressor 1 (= output frequency F of the inverter circuit 51) and the amount of heating of the refrigerant heater 30 (= opening of the proportional valve 33) are determined by the indoor units B ₁ , B Means for controlling according to the presence or absence of the operation request of ₂ . (12) Means for opening and closing the two-way valves 13 and 23 according to the presence or absence of an operation request for the indoor units B ₁ and B ₂ during the heating operation.

(13) When one of the two-way valves 13 and 23 is open and the other is closed during the heating operation, when the closed two-way valve is opened, the flow control valve 7 is first opened to a predetermined opening degree when the closed two-way valve is opened. means for opening the two-way valve after a certain period of time t ₁ and then. This is to reduce the pressure difference before and after the two-way valve before opening the two-way valve corresponding to the increased indoor unit when the number of operating indoor units increases. (14) During the heating operation, the degree of superheat of the refrigerant in the refrigerant heater 30 (= the detection temperature of the refrigerant temperature sensor 41 and the refrigerant temperature sensor 4
(2) a means for detecting the difference from the detected temperature. (15) Means for controlling the degree of opening of the electronic expansion valves 11 and 21 so that the detected refrigerant superheat degree becomes a constant value. Next, the operation of the above configuration will be described with reference to the time chart of FIG. It is assumed that a cooling operation mode and a desired room temperature are set by the remote controller 62 of each of the indoor units B ₁ and B ₂ , and that an operation start operation is performed.

[0026] In this case, for example, to open the two-way valve 13 if there is operation request of the indoor unit B _1, if there is no operation demand of the indoor unit B ₂ to close the two-way valve 23. Further, the flow control valve 7 is fully closed, and the compressor 1 is started.

When the compressor 1 is started, the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the outdoor heat exchanger 3, the electronic expansion valve 11, and the indoor heat exchanger 1 as shown by solid arrows in FIG.
2, two-way valve 13, four-way valve 2, check valve 5, accumulator
Flows through motor 6, the cooling operation of the indoor unit B ₁ is executed.

In this case, the capacity of the compressor 1 (= output frequency F of the inverter circuit 51) is controlled to a predetermined capacity corresponding to one cooling unit operation. Further, the degree of superheat of the refrigerant in the indoor heat exchanger 12 (= the difference between the temperature detected by the heat exchanger temperature sensor 15 and the temperature detected by the refrigerant temperature sensor 16) is detected, and the electronic control is performed so that the degree of superheat of the refrigerant becomes a constant value. The opening of the expansion valve 11 is controlled.

[0029] Thereafter, if Shojire the operation request from the indoor unit B _2, opening the two-way valve 23. Then, indoor heat exchanger 1
Refrigerant also flows through ₂ , and the cooling operation of the indoor unit B2 is started.

In this case, the capacity of the compressor 1 is controlled to a predetermined capacity corresponding to the operation of two cooling units. Further, the degree of superheat of the refrigerant in the indoor heat exchanger 12 (= the difference between the temperature detected by the heat exchanger temperature sensor 15 and the temperature detected by the refrigerant temperature sensor 16) is detected, and the degree of superheat of the refrigerant in the indoor heat exchanger 22 is detected. (= The difference between the temperature detected by the heat exchanger temperature sensor 25 and the temperature detected by the refrigerant temperature sensor 26), and the opening degrees of the electronic expansion valves 11 and 21 are controlled so that the superheat degrees of both refrigerants become constant values. . Further, it is assumed that the heating operation mode and the desired room temperature are set by the remote controller 62 of each of the indoor units B ₁ and B ₂ , and the operation start operation is performed.

[0031] In this case, for example, to open the two-way valve 13 if there is operation request of the indoor unit B _1, if there is no operation demand of the indoor unit B ₂ to close the two-way valve 23. Further, the flow control valve 7 is fully closed, and the compressor 1 is started.

When the compressor 1 is started, the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2 as shown by a broken arrow in FIG.
Two-way valve 13, an indoor heat exchanger 12, electronic expansion valve 11, two-way valve 8, the refrigerant heater 30, Accu - stuffiness - flows through motor 6, the heating operation of the indoor unit B ₁ is being started.

In this case, the capacity of the compressor 1 and the heating amount of the refrigerant heater 30 are controlled to a predetermined capacity corresponding to one heating operation. Further, the degree of superheat of the refrigerant in the refrigerant heater 30 (= the difference between the detected temperature of the refrigerant temperature sensor 41 and the detected temperature of the refrigerant temperature sensor 42) is detected, and the electronic expansion valve is set so that the detected degree of superheat of the refrigerant becomes a constant value. 11 is controlled.

Thereafter, when an operation request is issued from the indoor unit B ₂ , the corresponding two-way valve 23 is opened, but the two-way valve 23 is not opened immediately, and the flow control valve 7 is previously set to a predetermined value. Open to opening. Then, after a certain period of time t ₁ based on the lapse of time of the internal timer after the opening of the flow control valve 7,
Open the two-way valve 23. When the flow control valve 7 is opened, a temporary hold is added on the way to gradually increase the flow rate of the refrigerant.

When the flow control valve 7 is opened in advance in this way, the refrigerant flows downstream of the two-way valve 23, and the two-way valve 23 opens with a reduced pressure difference between the front and rear. In this case, since no load is applied to the two-way valve 23, the life of the two-way valve 23 is not adversely affected. Moreover, no loud refrigerant noise is generated when the two-way valve 23 is opened. When the two-way valve 23 is opened, the refrigerant flows to the indoor heat exchanger 12, the heating operation of the indoor unit B ₂ is started.

[0036] After a while, if the operation request of the indoor unit B ₂ stops, the corresponding two-way valve 23 is closed. At this time, the capacity of the compressor 1 is slightly reduced, the heating amount of the refrigerant heater 30 is set to a minimum state, and the electronic expansion valve 21 is maintained at a predetermined opening. This is a so-called blow operation for recovering the remaining refrigerant in the stopping indoor unit B _2, returns to the normal one operation after performing the blowing operation for a predetermined time.

As described above, when the number of operating indoor units increases during the heating operation, the pressure difference before and after the two-way valve is reduced before opening the two-way valve corresponding to the increased indoor unit. Thus, the load on the two-way valve can be reduced, and the life of the two-way valve can be improved. In addition, the generation of the refrigerant noise can be prevented, and the uncomfortable feeling can be eliminated, so that the reliability can be improved. Next, a second embodiment of the present invention will be described. This embodiment corresponds to the air conditioner of the second aspect. The configurations of the refrigeration cycle and the control circuit are the same as those of the first embodiment, but the functional units of the indoor control units 60 and 60 and the outdoor control unit 50 are different from those of the first embodiment. First, the indoor control units 60, 60
The following functional means (1) to (3) are provided.

(1) Means for transmitting an operation mode command or set room temperature data by operating the remote controller 62 to the outdoor control unit 50 as a serial signal synchronized with the power supply voltage. [Same as (1) of the first embodiment].

(2) The difference between the detected temperature of the indoor temperature sensor 61 and the set indoor temperature of the remote controller 62 (ie, the air-conditioning load) is detected, and the outdoor control unit 50 is set as a required capacity and uses a serial signal synchronized with the power supply voltage. Means to send to. (3) Means for sending the detected temperature data of the heat exchanger temperature sensors 15 and 25 to the outdoor control unit 50 as a serial signal synchronized with the power supply voltage. [Same as (3) of the first embodiment]. Outdoor control unit 5
0 has the following functional means (4) to (16).

(4) The refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the outdoor heat exchanger 3, the check valve 4, the electronic expansion valve 1 based on the cooling operation mode command from the indoor units B ₁ and B _2.
1,21, indoor heat exchangers 12,22, two-way valves 13,2
3, means for flowing through the four-way valve 2, the check valve 5, and the accumulator 6 to execute the cooling operation. [(4) of the first embodiment]
Same as]. (5) Means for controlling the capacity of the compressor 1 (= the output frequency F of the inverter circuit 51) according to the sum of the required capacity of the indoor units B ₁ and B ₂ during the cooling operation.

[0041] (6) the cooling operation, among the two-way valve 13, 23 opens the two-way valve corresponding to the direction of the required capacity of the indoor unit B _1, B ₂ larger, the two-way valve corresponding to the smaller Close means.

(7) During the cooling operation, the indoor units B ₁ and B
Refrigerant evaporation temperature at ₂ (= heat exchanger temperature sensors 15, 25
Flow rate adjustment so that the difference (or ratio) between Tc ₁ and Tc ₂ becomes a predetermined relationship based on the required capacity of the indoor units B ₁ and B ₂ (= a value corresponding to the required capacity ratio or difference). Means for controlling the opening of the valve 7.

(8) During the cooling operation, the indoor heat exchangers 12, 2
Means for detecting the degree of superheat of the refrigerant at 2 (= the difference between the detected temperatures of the heat exchanger temperature sensors 15, 25 and the detected temperatures of the refrigerant temperature sensors 16, 26). [Same as (8) of the first embodiment]. (9) Means for controlling the degree of opening of the electronic expansion valves 11 and 21 so that the detected refrigerant superheat degrees become constant values. [Same as (9) of the first embodiment].

(10) Based on the heating operation mode command from the indoor units B ₁ and B ₂ , the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the two-way valves 13 and 23, and the indoor heat exchangers 12 and 2.
2, electronic expansion valves 11, 21, two-way valve 8, refrigerant heater 3
0, means for flowing through the accumulator 6 to perform the heating operation.

(11) During the heating operation, the capacity of the compressor 1 (= output frequency F of the inverter circuit 51) and the heating amount of the refrigerant heater 30 (= combustion amount of the gas burner 31) are determined by the indoor units B ₁ and B _2. Means to control according to the sum of required capabilities of

(12) During the heating operation, among the two-way valves 13 and 23, the two-way valve corresponding to the larger one of the required capacity of the indoor units B ₁ and B ₂ is opened, and the two-way valve corresponding to the smaller one is opened. Close means.

(13) During the heating operation, the indoor heat exchangers 12, 2
2 (= refrigerant temperature sensors 16, 26)
The flow rate is adjusted so that the difference (or ratio) between Tg ₁ and Tg ₂ has a predetermined relationship based on the required capacity of the indoor units B ₁ and B ₂ (= a value corresponding to the required capacity ratio or difference). Means for controlling the opening of the valve 7. (14) Means for setting the flow control valve 7 to a predetermined opening before opening the two-way valves 13 and 23 when the operation state of the indoor units B ₁ and B ₂ changes during the heating operation.

(15) Means for detecting the degree of superheating of the refrigerant in the refrigerant heater 30 (= the difference between the detected temperature of the refrigerant temperature sensor 41 and the detected temperature of the refrigerant temperature sensor 42) during the heating operation. [First
Same as (14) of Example). (16) Means for simultaneously controlling the opening degrees of the electronic expansion valves 11 and 21 by the same amount so that the detected refrigerant superheat degree becomes a constant value.
[Same as (15) of the first embodiment]. Next, the operation of the above configuration will be described.

At the time of the cooling operation in the indoor units B ₁ and B ₂ ,
The two-way valve 13 on the side where the required capacity of the indoor units B ₁ and B ₂ is large, for example, the indoor unit B ₁ is opened, and the two-way valve 23 on the side where the required capacity is small, for example, the indoor unit B ₂ is closed.

Then, the compressor 1 is started, and the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the outdoor heat exchanger 3, the electronic expansion valves 11, 21 and the indoor heat exchanger as shown by solid arrows in FIG. 1
2, 22, the two-way valve 13, the four-way valve 2, the check valve 5, and the accumulator 6 are flowed to start the parallel cooling operation of the indoor units B ₁ and B ₂ . During the cooling parallel operation, the capacity of the compressor 1 (= the output frequency F of the inverter circuit 51) is controlled in accordance with the sum of the required capacity of the indoor units B ₁ and B ₂ .

At the same time, the absolute value ΔTc of the difference between the refrigerant evaporation temperatures Tc ₁ and Tc _{2 in} the indoor units B ₁ and B ₂ (= the detected temperatures of the heat exchanger temperature sensors 15 and 25) is determined by the indoor units B ₁ and B 2 The opening of the flow control valve 7 is controlled so as to have a predetermined value corresponding to the ratio of the required capacity of ₂ .

[0052] By this flow rate control of the opening degree of the adjustment valve 7, the amount of the refrigerant flowing through the smaller side of the indoor unit B ₂ of the required capacity is set to the proper state corresponding to the required capacity. Consequently, the amount of the refrigerant flowing to the indoor unit B ₁ is set to the proper state corresponding to the required capacity of the indoor unit B _1.

The degree of superheat of the refrigerant in the indoor heat exchangers 12, 22 (= the difference between the detected temperatures of the heat exchanger temperature sensors 15, 25 and the detected temperatures of the refrigerant temperature sensors 16, 26) is detected.
The degrees of opening of the electronic expansion valves 11 and 21 are controlled such that the detected superheat degrees of the refrigerant become constant values. On the other hand, the heating alone operation of the indoor unit B _1, opens the two-way valve 13 of the driving side, closing stop-side two-way valve 23. Further, the flow control valve 7 is fully closed.

Then, the compressor 1 is started, and the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the two-way valve 13, the indoor heat exchanger 12, the electronic expansion valves 11, The air flows through the side valve 8, the refrigerant heater 30, and the accumulator 6, and the indoor unit B starts the single heating operation.

[0055] During the heating operation of this alone, the ability of the compressor 1 and heating amount of the refrigerant heater 30 (= output frequency F of the inverter circuit 51) (= the amount of combustion gas burner 31) to the required capacity of the indoor unit B ₁ Control according to. Further, the degree of superheat of the refrigerant in the refrigerant heater 30 (= the difference between the detected temperature of the refrigerant temperature sensor 41 and the detected temperature of the refrigerant temperature sensor 42) is detected, and the electronic expansion valve is set so that the detected degree of superheat of the refrigerant becomes a constant value. 11 is controlled.

In the heating parallel operation of the indoor units B ₁ and B ₂ , the side having the higher required capacity, for example, the indoor unit B
Open ₁ side of the two-way valve 13, the required capacity of the smaller side for example closing the indoor unit B ₂ side of the two-way valve 23.

In this case, the capacity of the compressor 1 (= output frequency F of the inverter circuit 51) and the heating amount of the refrigerant heater 30 (= combustion amount of the gas burner 31) are determined by the indoor units B ₁ ,
Controlled according to the sum of the required capacity of B _2.

At the same time, the absolute values ΔTg of the differences between the temperatures Tg ₁ and Tg ₂ of the refrigerant flowing into the indoor heat exchangers 12 and 22 (= the detected temperatures of the refrigerant temperature sensors 16 and 26) are determined by the indoor units B ₁ and B ₂ The opening degree of the flow control valve 7 is controlled so as to be a predetermined value corresponding to the ratio of the required capacity of the fuel cell.

[0059] By this flow rate control of the opening degree of the adjustment valve 7, the amount of the refrigerant flowing through the smaller side of the indoor unit B ₂ of the required capacity is set to the proper state corresponding to the required capacity. Consequently, the amount of the refrigerant flowing to the indoor unit B ₁ is set to the proper state corresponding to the required capacity of the indoor unit B _1.

The degree of superheat of the refrigerant in the refrigerant heater 30 (=
The difference between the detected temperature of the refrigerant temperature sensor 41 and the detected temperature of the refrigerant temperature sensor 42) is detected, and the opening degrees of the electronic expansion valves 11 and 21 are simultaneously controlled by the same amount so that the detected refrigerant superheat degree becomes a constant value. I do.

By the way, in the heating alone operation, the two-way valve corresponding to the stop-side indoor unit is closed, and in the parallel heating operation, the two-way valve corresponding to the indoor unit having the smaller required capacity is closed. A pressure difference is applied to both sides of the one-way valve.

Therefore, when the operation state of the indoor units B ₁ and B ₂ changes, for example, when the operation of one indoor unit is switched from one unit to the operation of two units, or when the indoor unit on the operation side stops and the indoor unit on the stop side is replaced, When the unit starts operation or when switching from the operation of two compressors to the operation of one low-capacity indoor unit, the control shown in FIG. 4 is executed. Note that the indoor unit B ₁ is stopped operation, the indoor unit B ₂ is described as an example when starting operation instead. First, before opening the two-way valve 23 on the driving side,
To start the time count t _1.

Until the time count t ₁ reaches the set time a, the operating frequency F of the compressor ₁ is set to the set value F _S and the flow regulating valve 7 is set to the predetermined opening. At this time, the refrigerant flows into the downstream side of the two-way valve 23, and the pressure difference before and after the two-way valve 23 decreases.

When the time count t ₁ reaches the set time a, the two-way valve 23 is opened. At this time, since the pressure difference between the front and rear of the two-way valve 23 is reduced, no load is applied to the two-way valve 23, so that the life of the two-way valve 23 is not adversely affected. When the two-way valve 23 is opened, the refrigerant flows to the indoor heat exchanger 12, the heating operation of the indoor unit B ₂ is started. At the same time when the two-way valve 23 is opened, the time count t ₂ is started. After the time count t ₂ reaches the set time b, the stop-side two-way valve 13 is closed.

At the same time as the two-way valve 13 is closed, a time count t ₃ is started, and the time count t ₃ is equal to the set time c.
Is reached, the flow control valve 7 is fully closed. At this time, the expansion valve 11 on the stop side is kept open.

Here, the reason why the set time c is secured until the flow control valve 7 is fully closed and the expansion valve 11 is opened is that the indoor heat exchanger 12 on the stop side is provided with This is for blowing the refrigerant. At the time of this refrigerant blow, the operating frequency of the compressor 1 is maintained at a predetermined value.
The time count t after the flow control valve 7 is fully closed.
_{When the} set time d based on ₄ has elapsed, the stop-side expansion valve 11 is closed for the first time.

As described above, during the heating operation, the indoor unit B
_1, when the operation state of B ₂ is changed, the two-way valve 13,
By opening the flow regulating valve 7 before any one of the valves 23 opens, and reducing the pressure difference before and after the two-way valves 13 and 23, the load on the two-way valve can be reduced. The service life of the one-way valve can be improved. In addition, the generation of the refrigerant noise can be prevented, and the uncomfortable feeling can be eliminated, so that the reliability can be improved. In each of the above embodiments, the case where the number of indoor units is two has been described as an example, but the number is not limited.

[0068]

As described above, according to the present invention,

In the air conditioner of the first aspect, when the number of operating indoor units increases during the heating operation, the flow control valve is opened before opening the two-way valve corresponding to the increased indoor unit,
Since the pressure difference before and after the two-way valve is reduced, the load on the two-way valve can be reduced when the two-way valve is opened due to an increase in the number of operating indoor units. Accordingly, the life of the two-way valve can be improved, and furthermore, the generation of loud refrigerant noise can be prevented, and the uncomfortable feeling can be eliminated, resulting in excellent reliability.

According to the air conditioner of the second aspect, when the operation state of the indoor unit changes during the heating operation, the flow regulating valve is opened before opening each two-way valve to reduce the pressure difference before and after each two-way valve. When the two-way valve is opened due to an increase in the number of operating indoor units, the burden on the two-way valve can be reduced, and the life of the two-way valve can be improved. This makes it possible to prevent the generation of loud refrigerant noise and to eliminate discomfort, thereby achieving excellent reliability.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a refrigeration cycle according to a first embodiment and a second embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a control circuit in each embodiment.

FIG. 3 is a time chart for explaining the operation of the first embodiment during the heating operation.

FIG. 4 is a flowchart illustrating an operation during a heating operation according to the second embodiment.

[Explanation of symbols]

1: Variable capacity compressor, 2: Four-way valve, 3: Outdoor heat exchanger,
7: Electronic flow control valve, 12, 22: Indoor heat exchanger, 1
3, 23: two-way valve, 30: refrigerant heater, 50: outdoor controller, 60: indoor controller.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 57-81368 (JP, U) JP-B 61-52913 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) F24F 11/02 102 F05B 13/00 104

Claims (2)

(57) [Claims] An outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger, a plurality of indoor units each having an indoor heat exchanger, and the compressor, a four-way valve, an outdoor heat exchanger, a decompressor, A refrigeration cycle communicating with a parallel circuit of each indoor heat exchanger, and a flow control valve provided in communication with each gas side pipe between each indoor heat exchanger and the four-way valve,
In each of the gas side pipes, a two-way valve is provided at a position on the four-way valve side of the communication position of the flow control valve, and communicates from a communication portion between the outdoor heat exchanger and the pressure reducer to a suction port side of the compressor. Means for performing cooling operation by flowing refrigerant discharged from the compressor through a four-way valve, an outdoor heat exchanger, a decompressor, each indoor heat exchanger, and each two-way valve. Means for flowing the refrigerant discharged from the compressor through a four-way valve, each two-way valve, each indoor heat exchanger, a decompressor, and a refrigerant heater to execute a heating operation; When the number of units increases, before opening the two-way valve corresponding to the increased indoor unit, the flow control valve is opened, and the refrigerant flows into the downstream side of the two-way valve to reduce the pressure difference before and after the two-way valve in advance. An air conditioner comprising: 2. An outdoor unit having a compressor, a four-way valve and an outdoor heat exchanger, a plurality of indoor units each having an indoor heat exchanger, and the compressor, a four-way valve, an outdoor heat exchanger, a decompressor, A refrigeration cycle communicating with a parallel circuit of each indoor heat exchanger, and a flow control valve provided in communication with each gas side pipe between each indoor heat exchanger and the four-way valve,
In each of the gas side pipes, a two-way valve is provided at a position on the four-way valve side of the communication position of the flow control valve, and communicates from a communication portion between the outdoor heat exchanger and the pressure reducer to a suction port side of the compressor. Means for performing cooling operation by flowing refrigerant discharged from the compressor through a four-way valve, an outdoor heat exchanger, a decompressor, each indoor heat exchanger, and each two-way valve. Means for flowing the refrigerant discharged from the compressor through a four-way valve, each two-way valve, each indoor heat exchanger, a decompressor, and a refrigerant heater to execute a heating operation; Means of opening and closing the two-way valve corresponding to the larger of the required capacity of each indoor unit among the valves, and closing the two-way valve corresponding to the smaller one, the temperature of the refrigerant flowing into each indoor heat exchanger during the heating operation is The flow rate adjustment is performed so as to have a predetermined relationship based on the required capacity of each indoor unit. Means for controlling the opening of the valve, and means for setting the flow regulating valve to a predetermined opening before the opening of each of the two-way valves when the operating state of each indoor unit changes during heating operation. An air conditioner characterized by that: