JP2875665B2 - 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 a multi-room heat pump type air conditioner in which a plurality of indoor units are connected to one heat source unit. The present invention relates to an air conditioner capable of simultaneously performing cooling in the unit and heating in the other indoor unit, particularly to a refrigerant flow controller.

[0002]

2. Description of the Related Art FIG. 28 is a diagram showing the overall construction of an example of a conventional heat pump type air conditioner. In FIG. 5 is an indoor heat exchanger, 6 is a first connection pipe,
Reference numeral 7 denotes a second connection pipe, and reference numeral 9 denotes a first flow control device.

Next, the operation of the conventional air conditioner will be described. First, when performing the cooling operation, the compressor 1
The discharged high-temperature and high-pressure refrigerant gas passes through the four-way valve 2, exchanges heat with air in the heat source device side heat exchanger 3, is condensed and liquefied, flows into the indoor unit through the second connection pipe 7, and The pressure is reduced to a low pressure by the first flow control device 9 and heat exchanges with indoor air in the indoor heat exchanger 5 to evaporate and gasify, thereby cooling the room. The refrigerant in this gas state constitutes a circulation cycle that is drawn into the compressor 1 from the first connection pipe 6 through the four-way valve 2 and the accumulator 4, and performs a cooling operation.

In the heating operation, the compressor 1
The discharged high-temperature and high-pressure refrigerant gas flows into the indoor unit through the four-way valve 2 and the first connection pipe 6, and exchanges heat with the indoor air in the indoor heat exchanger 5 to condense and liquefy, thereby heating the room. I do. The refrigerant in the liquid state is decompressed to a low-pressure gas-liquid two-phase state by the first flow control device 9, flows into the heat source unit side heat exchanger 3 through the second connection pipe 7, and is cooled by air and heat. It exchanges and evaporates to a gaseous state, forms a circulation cycle that is sucked into the compressor 1 through the four-way valve 2 and the accumulator 4, and performs a heating operation.

[0005] Fig. 29 is an overall configuration diagram showing another example of a conventional heat pump type air conditioner. In Fig. 29, reference numeral 24 denotes low pressure saturation temperature detecting means. In the conventional air conditioner, when performing the cooling operation, the low-pressure saturation temperature detecting means 24 is used.
The capacity of the compressor 1 is controlled such that the detected temperature of the compressor 1 matches a predetermined value.

[0006]

Since the conventional air conditioner is configured as described above, since all the indoor units can be operated only for cooling or heating, heating is performed in a place where cooling is required. On the contrary, there is a problem that cooling is performed in a place where heating is required. In particular, when installed in a large-scale building, the air conditioning load is significantly different between an interior part and a perimeter part, or between a general office and a computer room, such as a computer room, where the air conditioning load is significantly different. Had become. In addition, at the time of cooling operation start after a long stop, at the time of cooling operation immediately after heating operation,
When the number of cooling operation indoor units increases, a large amount of liquid refrigerant accumulates in an accumulator or the like, and the inlet of the first flow control device 9 of the cooling indoor unit enters a gas-liquid two-phase state due to insufficient refrigerant, and the first flow rate is increased. The flow path pressure loss of the control device 9 increases, and the low pressure side pressure of the refrigerant circuit decreases. Due to the decrease in the low-pressure side pressure, the amount of circulating refrigerant is reduced, or the temperature detected by the low-pressure saturation temperature detecting means 24 is also reduced. The conventional air conditioner causes such a problem, and selectively performs cooling and heating for each indoor unit.
In addition, there is a problem that cooling cannot be performed simultaneously and stably in one indoor unit and heating cannot be performed in the other indoor unit at the same time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and selectively performs cooling and heating for each indoor unit. It is an object of the present invention to obtain an air conditioner capable of performing simultaneous cooling and heating operations.

[0008]

An air conditioner according to a first aspect of the present invention includes a heat source unit having a compressor, a four-way valve and a heat source unit side heat exchanger, and an indoor heat exchanger. And a plurality of indoor units having a first flow control device and a pipe connected to each other, and a refrigerant is supplied from the heat source unit to the plurality of indoor units to perform an air conditioning operation. Intake air temperature detection means for detecting the air temperature,
An opening setting unit that sets a valve opening of the first flow control device; and a first valve opening control unit that controls the valve opening of the first flow control device to the set valve opening. A plurality of opening setting control zones corresponding to the required air conditioning capacity based on the difference between the detected temperature of the intake air temperature detecting means and the set target temperature of the indoor unit, and setting the minimum valve opening for each control zone; The valve opening of the first flow control device is adjusted and controlled at a predetermined ratio up to the minimum valve opening.

[0009]

An air conditioner according to a second aspect of the present invention has a compressor, a four-way valve, and a heat source-side heat exchanger.
Air connected to one heat source unit and a plurality of indoor units having an indoor heat exchanger and a first flow control device by piping, and supplying a refrigerant from the heat source unit to the plurality of indoor units to perform a cooling / heating operation. In the harmony device, when the indoor unit is stopped, the first flow control device is kept closed at a predetermined opening for a predetermined time and then closed.

An air conditioner according to a third aspect of the present invention is the air conditioner according to the second aspect, wherein the first air conditioner operates when the indoor unit is stopped.
Fourth valve opening control means for setting the valve opening of the flow control device to a predetermined ratio of the valve opening immediately before the stop, and the first flow control device holds the valve opening of a predetermined ratio. Clock means for measuring time.

An air conditioner according to a fourth aspect of the present invention has a compressor having a compressor, a four-way valve, and a heat source device side heat exchanger.
A heat source unit and a plurality of indoor units having an indoor heat exchanger and a first flow control device are connected by piping, and a cooling / heating operation is performed by supplying a refrigerant from the heat source unit to the plurality of indoor units. A subcool amount detecting means for detecting an indoor unit inlet subcool amount during the cooling operation; and a capacity control target value of the compressor is determined according to the subcool amount detected by the subcool amount detecting means. An air conditioner provided with compressor capacity control means for controlling the capacity of the compressor based on the first and second connection pipes connecting the heat source unit and the plurality of indoor units to each other. A first branch unit having a valve device for switchably connecting one of the indoor heat exchangers of the indoor unit to the first connection pipe or the second connection pipe; Connected to the other of the exchangers via a first flow control device, A second branch portion connected to the second connection pipe via the second flow control device, a second branch portion connected to the first connection pipe, and a third flow control device And a second pipe on the side of each indoor unit in the second branch, which is provided downstream of the third flow control device,
A second heat exchange section for exchanging heat between the junction of the connection pipe and the bypass pipe, and a pipe for connecting the four-way valve and the accumulator in the order of a four-way valve, an accumulator, and a compressor A low-pressure saturation temperature detecting means disposed in the middle, a second pressure detecting means disposed between the first flow control device and the second flow control device, and an upstream of the third flow control device A first temperature detecting means disposed between the third flow control device and the second heat exchanging section on the side, and the subcool amount detecting means comprises a second pressure detecting means and a first temperature detecting means. A compressor capacity control means for determining an indoor unit inlet subcool amount from a difference between a saturation temperature of the pressure detected by the second pressure detection means and a temperature detected by the first temperature detection means. Flow rate control device inlet subcool amount determining means;
A low pressure saturation temperature target value determining means for determining a low pressure saturation temperature target value as a capacity control target value based on the indoor unit inlet subcool amount determined by the flow rate control device inlet subcool amount determining means; and a low pressure saturation temperature target value and a low pressure. Capacity control means for controlling the capacity of the compressor in accordance with the difference between the temperature detected by the saturation temperature detection means and the capacity of the compressor in accordance with the indoor unit inlet subcool amount during the cooling operation. This is to ensure a refrigerant circulation amount.

[0013]

[0014]

[0015]

An air conditioner according to a fifth aspect of the present invention includes a heat source unit having a compressor, a four-way valve, a heat source unit side heat exchanger and an accumulator, an indoor side heat exchanger and a first heat source unit.
A plurality of indoor units having a flow control device are connected by piping, and in an air conditioner that performs cooling and heating operation by supplying a refrigerant to a plurality of indoor units from a heat source unit, a lower part of an accumulator and an outlet pipe of the accumulator are connected. A fifth flow control device provided in a pipe route to be connected, and a subcool amount detecting means for detecting an indoor unit entrance subcool amount during cooling operation;
Fifth valve opening control means for controlling the valve opening of the fifth flow control device in accordance with the subcool amount detected by the subcool amount detecting means, and an accumulator in accordance with the indoor unit inlet subcool amount during the cooling operation The liquid refrigerant stored in the compressor is supplied to the compressor to ensure a sufficient refrigerant circulation amount.

[0017]

An air conditioner according to a sixth aspect of the present invention is the air conditioner according to the fifth aspect, wherein the heat source unit and a plurality of indoor units are connected via first and second connection pipes. A first branch unit having a valve device for switchably connecting one of the indoor heat exchangers of the indoor unit to the first connection pipe or the second connection pipe, and the indoor heat exchanger of the plurality of indoor units. Connected to the other of the exchangers via a first flow control device and
A second branch portion connected to the second connection pipe via the flow control device of (1), wherein the subcool amount detection means
And a second pressure detecting means and a first temperature detecting means disposed between the flow control device and the second flow control device.

An air conditioner according to a seventh aspect of the present invention is the air conditioner according to the sixth aspect, wherein the second branch portion is connected to the first connection pipe, and a third flow control device is provided. A bypass pipe, provided downstream of the third flow control device,
A second heat exchanging unit for exchanging heat between a junction of the second connection pipes on the indoor unit side and a bypass pipe in the second branch unit, wherein the first temperature detecting unit is a third heat exchanging unit; The fifth valve opening control means is disposed between the third flow control device and the second heat exchange section on the upstream side of the flow control device, and the fifth valve opening degree control means detects the saturation temperature of the pressure detected by the second pressure detection means. Flow control device for determining an indoor unit sub-cooling amount from the difference between the temperature detected by the first temperature detecting unit and the temperature detected by the first temperature detecting unit; Fifth flow control device based opening degree determining means for determining the reference valve opening degree of the device, and fifth flow rate control based on the indoor unit inlet subcool amount determined by the third flow rate control device inlet subcool amount determining means. Fifth flow for determining the valve opening of the device as the reference valve opening or the special valve opening Are those composed of a control device opening determining means.

An air conditioner according to an eighth aspect of the present invention includes a heat source unit having a compressor, a four-way valve, a heat source unit side heat exchanger and an accumulator, an indoor side heat exchanger and a first heat source unit.
Pipe connection with a plurality of indoor units having a flow rate control device, supplying a refrigerant from the heat source unit to the plurality of indoor units, and selectively performing a cooling / heating operation for each of the plurality of indoor units, comprising an accumulator. A bypass circuit connecting a pipe connecting the compressor and the four-way valve and a high pressure gas pipe on the discharge side of the compressor, a subcool amount detecting means for detecting an indoor unit inlet subcool amount during cooling operation, and a subcool amount detecting means An air conditioner comprising: a sixth valve opening control unit that controls a valve opening of a bypass circuit in accordance with the indoor unit inlet subcool amount.
The heat source unit and the plurality of indoor units are connected via the first and second connection pipes, and one of the indoor heat exchangers of the plurality of indoor units is connected to the first connection pipe or the second connection pipe. A first branch unit having a switchable connectable valve device, and a second flow control device connected to the other of the indoor heat exchangers of the plurality of indoor units via a first flow control device; A second branch part connected to the second connection pipe via the device, a bypass pipe connecting the second branch part and the first connection pipe, and a third flow control device being provided; A second heat exchange unit that is provided downstream of the third flow control device and that performs heat exchange between an associated portion of the second connection pipe on each indoor unit side in the second branch and the bypass pipe. A second pressure detecting means disposed between the first flow control device and the second flow control device; A first temperature detecting means disposed between the third flow control device and the second heat exchanging section on the side, and the subcool amount detecting means comprises a second pressure detecting means and a first temperature detecting means. A sixth valve opening degree control means for detecting the saturation temperature of the pressure detected by the second pressure detection means and the first temperature.
Third flow control device inlet subcool amount determining means for determining an indoor unit inlet subcool amount from a difference between the detected temperature of the temperature detecting means and a bypass for controlling a valve opening of a bypass circuit based on the indoor unit inlet subcool amount. And a circuit valve open / close control means.

[0021]

[0022]

[0023]

[0024]

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the air conditioner of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 1 of the present invention. FIGS. 2 to 4 show an operation state during the cooling / heating operation in the first embodiment of FIG. 1, FIG. 2 is an operation state diagram of only the cooling or heating operation, and FIGS. FIG. 3 shows the operation of the operation, in which FIG. 3 shows a heating main body (when the heating operation capacity is larger than the cooling operation capacity), and FIG. 4 shows an operation operation state showing the cooling main body (when the cooling operation capacity is larger than the heating operation capacity). It is. In the first embodiment, the heat source device 1
The case where three indoor units are connected to the unit will be described.
The same applies when more than one indoor unit is connected.

In FIG. 1, A is a heat source unit, and B, C, and D are indoor units connected in parallel to each other as described later, and have the same configuration. E incorporates a first branch, a second flow controller, a second branch, a gas-liquid separator, a heat exchanger, a third flow controller, and a fourth flow controller as described later. It is a repeater. Reference numeral 1 denotes a compressor, 2 denotes a four-way valve for switching the refrigerant flow direction of the heat source unit, 3 denotes a heat source side heat exchanger, and 4 denotes an accumulator connected to the compressor 1 via the four-way valve 2. , The compressor 1, the four-way valve 2, the heat source device side heat exchanger 3 and the accumulator 4 constitute a heat source device A. 5 is three indoor units B, C, D
6 is a four-way valve 2 of the heat source unit A.
First connecting pipe connecting the relay E and the relay E, 6b, 6
c and 6d respectively connect the indoor side heat exchangers 5 of the indoor units B, C and D and the relay unit E, and a first connection pipe on the indoor unit side corresponding to the first connection pipe 6, and 7 is a heat source unit. A second connection pipe that is thinner than the first connection pipe 6 that connects the heat source device side heat exchanger 3 of A and the relay machine E. 7b, 7c and 7d connect the indoor-side heat exchangers 5 of the indoor units B, C and D to the repeater E via the first connection pipe 6, respectively, and connect the indoor heat exchangers 5 to the second connection pipe 7 respectively. It is a second connection pipe on the machine side. Reference numeral 8 denotes a first connection pipe 6b on the indoor unit side which is switchably connected to the first connection pipe 6b, 6c, 6d on the indoor unit side and to the first connection pipe 6 or the second connection pipe 7 side. , 6c, 6d
And a first connection pipe 6 and a second connection pipe 7 are three-way switching valves as valve devices capable of closing the flow.

Numeral 9 is connected in proximity to the indoor heat exchanger 5 and, during cooling, depends on the amount of superheat on the outlet side of the indoor heat exchanger 5 (in the present embodiment, a first valve opening control which will be described later). By means 52), at the time of heating, the first flow control device is controlled by the outlet side subcool amount of the indoor heat exchanger 5, and is connected to the second connection pipes 7b, 7c, 7d on the indoor unit side. 10 is a first connection pipe 6b, 6c on the indoor unit side,
6d, and a first branch portion including a three-way switching valve 8 that is switchably connected to the first connection pipe 6 or the second connection pipe 7. 11 is a second connection pipe 7b, 7 on the indoor unit side.
This is a second branch portion composed of c and 7d and the second connection pipe 7. Reference numeral 12 denotes a gas-liquid separation device provided in the middle of the second connection pipe 7. The gas phase portion is connected to the first port 8 a of the three-way switching valve 8, and the liquid phase portion is connected to the second branch portion 11. It is connected. Reference numeral 13 denotes an openable and closable second flow control device (here, an electric expansion valve) connected between the gas-liquid separation device 12 and the second branch portion 11.

Reference numeral 14 denotes a bypass pipe connecting the second branch portion 11 and the first connection pipe 6, and reference numeral 15 denotes a bypass pipe 14.
A third flow control device (here, an electric expansion valve) provided in the middle of the second branch portion 16a is provided downstream of the third flow control device 15 provided in the middle of the bypass pipe 14. 11, the second connection pipe 7b on each indoor unit side,
A second heat exchange between the meeting sections 7c and 7d
The heat exchange section. 16b, 16c, 16d are provided downstream of the third flow control device 15 provided in the middle of the bypass pipe 14, respectively, and the second connection pipes 7b, 7c, This is a third heat exchange section that performs heat exchange with each of the heat exchange units 7d.

Reference numeral 19 is provided downstream of the third flow control device 15 in the bypass pipe 14 and downstream of the second heat exchange unit 16a, and is connected to the gas-liquid separation device 12 and the second flow control device 1.
A first heat exchange section 17 for exchanging heat with a pipe connecting the third connection section 3 and a fourth openable / closable flow rate connected between the second branch section 11 and the first connection pipe 6; It is a control device (here, an electric expansion valve). On the other hand, reference numeral 32 denotes a third check valve provided between the heat source unit-side heat exchanger 3 and the second connection pipe 7, and a third check valve 32 is provided between the heat source unit-side heat exchanger 3 and the second connection pipe. Only the flow of the refrigerant to the pipe 7 is allowed. Reference numeral 33 denotes a fourth check valve provided between the four-way valve 2 of the heat source unit A and the first connection pipe 6, and only a fourth check valve from the first connection pipe 6 to the four-way valve 2 is provided. Allow refrigerant flow.

Reference numeral 34 denotes the four-way valve 2 of the heat source unit A and the second
A fifth check valve provided between the connection pipe 7 and
Refrigerant flow is allowed only from the four-way valve 2 to the second connection pipe 7. Reference numeral 35 denotes the heat source unit side heat exchanger 3 and the first
A sixth check valve provided between the connection pipe 6 and
Refrigerant flow is allowed only from the first connection pipe 6 to the heat source unit side heat exchanger 3. The third, fourth, fifth, and sixth check valves 32, 33, 34, and 35 constitute a flow path switching device 40. 25 is a first pressure detecting means provided between the first branch section 10 and the second flow control device 13, 26 is a second flow control device 13 and a fourth flow control device 17
And a second pressure detecting means provided between the first pressure detecting means and the second pressure detecting means.

Reference numeral 50 denotes suction air temperature detecting means for detecting the temperature of the suction air of the indoor heat exchanger 5, and reference numeral 51 denotes the suction air temperature detected by the suction air temperature detecting means 50, a target temperature preset for the indoor unit, and The opening degree setting means 52 for setting the minimum opening degree according to the difference between the first and second opening degrees is a first valve opening degree control means for controlling the opening degree according to the minimum opening degree. The setting means 51 and the first valve opening degree control means 52 constitute a control mechanism of the first flow control device 9.

Next, the operation of the first embodiment will be described. First, the case of only the cooling operation will be described with reference to FIG. As shown by a solid line arrow in the figure, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2 and exchanges heat with outdoor air in the heat source unit side heat exchanger 3 to be condensed and liquefied.
Third check valve 32, second connection pipe 7, gas-liquid separator 1
2, in the order of the second flow control device 13, and further the second branch portion 11, the second connection pipes 7b, 7c, 7 on the indoor unit side.
and d flows into each of the indoor units B, C, and D. The refrigerant flowing into each of the indoor units B, C, and D is supplied to a flow control unit 5 described later.
The pressure is reduced to a low pressure by a first flow control device 9 controlled by 2 and heat is exchanged with indoor air in an indoor heat exchanger 5 to evaporate and gasify, thereby cooling the room.

The refrigerant in the gas state is supplied to the first connection pipes 6b, 6c, 6d on the indoor unit side, the three-way switching valve 8,
, The first connection pipe 6, the fourth check valve 33,
A circulation cycle is drawn through the compressor 1 through the four-way valve 2 and the accumulator 4 of the heat source unit, and performs a cooling operation. At this time, the first port 8a of the three-way switching valve 8 is closed, and the second port 8b and the third port 8c are open. At this time, since the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure,
Flow through the check valve 32 and the fourth check valve 33.

At the time of this cycle, a part of the refrigerant that has passed through the second flow control device 13 enters the bypass pipe 14 and is reduced to a low pressure by the third flow control device 15 so that the third heat exchange portion 16b , 16c, and 16d, heat exchange is performed between the second connection pipes 7b, 7c, and 7d on the indoor unit side of the second branch section 11, and the second heat exchange section 16a performs second heat exchange.
1 exchanges heat with the junction of the second connection pipes 7b, 7c, 7d on the side of each indoor unit, and furthermore, the first heat exchange section 19
Performs heat exchange with the refrigerant flowing into the second flow control device 13, and the evaporated refrigerant enters the first connection pipe 6 and the fourth check valve 33, and enters the four-way valve 2 of the heat source device. , And is sucked into the compressor 1 through the accumulator 4. On the other hand, the first, second, and third heat exchangers 19, 16a, 16b, 16c, and 16d exchange heat and are cooled, and the sub-cooled refrigerant in the second branch 11 is about to be cooled. It flows into the indoor units B, C and D.

Next, a case of only the heating operation will be described with reference to FIG. That is, as shown by a dotted arrow in the figure, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2, passes through the fifth check valve 34, the first connection pipe 7, the gas-liquid separation After passing through the device 12, the first branch portion 10, the three-way switching valve 8, and the first connection pipes 6b, 6c, 6d on the indoor unit side flow into the indoor units B, C, D in order, and the indoor air and Heat exchange to condense and liquefy and heat the room.

The refrigerant in the liquid state is controlled by the subcooling amount at the outlet of each indoor side heat exchanger 5 and passes through the first flow control device 9 which is almost fully open, and the second connection on the indoor unit side. The gas flows into the second branch portion 11 from the pipes 7b, 7c, and 7d, merges, and further passes through the fourth flow control device 17. Here, the pressure is reduced to a low-pressure gas-liquid two-phase state by one of the first flow control device 9 and the third and fourth flow control devices 15 and 17. The refrigerant decompressed to a low pressure flows through the first connection pipe 6 into the sixth check valve 35 of the heat source unit A and the heat exchange unit 3 on the heat source unit side, where it exchanges heat with outdoor air and evaporates. The refrigerant in the gaseous state passes through the four-way valve 2 of the heat source unit and the accumulator 4 to form a circulation cycle that is drawn into the compressor 1 to perform a heating operation. At this time, the three-way switching valve 8 has the second port 8b closed, and the first port 8a and the third port 8c open. At this time, the refrigerant is connected to the first connection pipe 6 on the low pressure side,
Although the second connection pipe 7 is on the high pressure side, it communicates with the suction side of the compressor 1 and the discharge side of the compressor 1 via the sixth check valve 35 and the fifth check valve 34, respectively. Therefore, the gas necessarily flows to the fifth check valve 34 and the sixth check valve 35.

Next, a description will be given of the case of mainly heating in the simultaneous operation of cooling and heating with reference to FIG. Here, the case where two indoor units B and C are going to heat and one indoor unit D is going to cool will be described. The high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is sent to the relay E through the four-way valve 2 through the fifth check valve 34 and the second connection pipe 7 as indicated by a dotted arrow in FIG. The first branch 10, the three-way switching valve 8, and the first connection pipe 6 on the indoor unit side pass through the gas-liquid separation device 12.
b, 6c, in order of heating, each indoor unit B, C to be heated
And heat exchanges with the indoor air in the indoor heat exchanger 5 to condense and liquefy and heat the room.

The condensed and liquefied refrigerant is controlled by the subcooling amount at the outlet of each of the indoor heat exchangers 5 of the indoor units B and C, and is slightly reduced in pressure through the first flow control device 9 which is almost fully opened. 2 flows into the second branch portion 11. Part of this refrigerant passes through the second connection pipe 7d on the indoor unit side, enters the indoor unit D to be cooled, and is subjected to a first flow rate control controlled by a first valve opening control means 52 described later. After entering the device 9 and being depressurized, it enters the indoor heat exchanger 5 and exchanges heat to evaporate to a gaseous state to cool the room.
Through d, it flows into the first connection pipe 6 via the three-way switching valve 8.

On the other hand, the other refrigerant is the first pressure detecting means 25
And the refrigerant having passed through the indoor unit D to be cooled through the fourth flow control device 17 which is controlled so that the pressure difference between the detected pressure and the pressure detected by the second pressure detecting means 26 is within a predetermined range. It merges and flows through the thick first connection pipe 6 into the sixth check valve 35 of the heat source unit A and the heat source unit side heat exchanger 3, where it exchanges heat with outdoor air and evaporates to a gas state. Become.

This refrigerant forms a circulation cycle which is drawn into the compressor 1 through the four-way valve 2 and the accumulator 4 of the heat source unit, and performs a heating-main operation. At this time, the difference between the evaporation pressure of the indoor side heat exchanger 5 of the indoor unit D to be cooled and the pressure of the heat source unit side heat exchanger 3 is reduced due to the switching to the thick first connection pipe 6. At this time, the second port 8b of the three-way switching valve 8 connected to the indoor units B and C is closed, and the first port 8a and the third port 8c are closed.
Is open, the first port 8a of the indoor unit D is closed,
The opening 8b and the third opening 8c are open. At this time, since the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure at this time, the fifth check valve 34 and the sixth check valve 35 are inevitable.
Distribute to

In this cycle, a part of the liquid refrigerant is supplied to the second connection pipes 7b, 7c,
7d, enters the bypass pipe 14 from the junction, and is decompressed to a low pressure by the third flow control device 15, so that the third heat exchange unit 1
6b, 16c, and 16d, between the second connection pipes 7b, 7c, and 7d on the indoor unit side of the second branch section 11, and between the indoors of the second branch section 11 by the second heat exchange section 16a. Exchanges heat with the associated portions of the second connection pipes 7b, 7c, 7d on the machine side,
The evaporated refrigerant is supplied to the first connection pipe 6 and the sixth check valve 35.
Through the four-way valve 2 and the accumulator 4 of the heat source unit,
It is sucked into the compressor 1. On the other hand, the second and third heat exchange units 1
6a, 16b, 16c, 16d, heat exchange and cooling,
The refrigerant in the second branch portion 11, which is sufficiently subcooled, flows into the indoor unit D to be cooled.

Next, a description will be given of a case where the cooling is mainly performed in the simultaneous cooling and heating operation with reference to FIG. Here, a case will be described in which two indoor units B and C are going to cool and one indoor unit D is going to heat. As shown by solid arrows in FIG. 1, the refrigerant gas discharged from the compressor 1 flows into the heat source unit side heat exchanger 3 via the four-way valve 2 and exchanges heat with outdoor air to form a two-phase valve. High temperature and high pressure state. Thereafter, the two-phase high-temperature high-pressure refrigerant is sent to the gas-liquid separator 12 of the relay E via the third check valve 32 and the second connection pipe 7. Here, the gaseous refrigerant is separated into the gaseous refrigerant and the liquid refrigerant, and the separated gaseous refrigerant is heated in the order of the first branch portion 10, the three-way switching valve 8, and the first connection pipe 6d on the indoor unit side. It flows into the indoor unit D, exchanges heat with the indoor air in the indoor heat exchanger 5 to condense and liquefy, and heats the room. Further, the pressure is controlled by the sub-cooling amount at the outlet of the indoor heat exchanger 5, passes through the first flow control device 9 which is almost fully opened, and is slightly reduced to an intermediate pressure between the high pressure and the low pressure (intermediate pressure). 2
Flows into the branching portion 11.

On the other hand, the remaining liquid refrigerant is controlled by the pressure detected by the first pressure detecting means 25 and the pressure detected by the second pressure detecting means 26 so as to keep the difference between the high pressure and the intermediate pressure constant. Through the flow controller 13 of the second branch 1
1 and merges with the refrigerant that has passed through the indoor unit D to be heated, and flows into the indoor units B and C in the order of the second connection pipes 7b and 7c on the indoor unit side. The refrigerant flowing into each of the indoor units B and C is decompressed to a low pressure by a first flow control device 9 controlled by a first valve opening control means 52 described later, and exchanges heat with indoor air to evaporate. It is gasified and cools the room. Further, the refrigerant in the gas state passes through the first connection pipes 6b and 6c, the three-way switching valve 8, and the first connection pipe 10 on the indoor unit side, passes through the first connection pipe 6, and the fourth check valve. 33, a circulation cycle is drawn into the compressor 1 via the four-way valve 2 of the heat source unit and the accumulator 4, and the cooling-main operation is performed.

At this time, the first port 8a of the three-way switching valve 8 connected to the indoor units B and C is closed, and the second port 8b and the third port 8c are open. The mouth 8b is closed,
The first port 8a and the third port 8c are open. At this time, the refrigerant naturally flows to the third check valve 32 and the fourth check valve 33 because the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure. In this cycle, a part of the liquid refrigerant is supplied to the second connection pipes 7b, 7c, 7 on the indoor unit side of the second branch portion 11.
d enters the bypass pipe 14 from the junction, and is reduced to a low pressure by the third flow control device 15,
b, 16c, and 16d, heat exchange is performed between the second connection pipes 7b, 7c, and 7d on the indoor unit side of the second branch section 11 and the second branch section is formed by the second heat exchange section 16a. 11 exchanges heat with the associated portions of the second connection pipes 7b, 7c, 7d on the indoor unit side of the indoor unit 11, and further exchanges the refrigerant flowing into the second flow control device 13 with the first heat exchange unit 19 with the refrigerant. Heat exchange between
The evaporated refrigerant enters the first connection pipe 6, the fourth check valve 33, and is sucked into the compressor 1 via the four-way valve 2 of the heat source unit and the accumulator 4. On the other hand, the first, second and third heat exchange units 1
The second branch portion 11, which is cooled by being exchanged with heat at 9, 16a, 16b, 16c, and 16d and has a sufficient subcool.
Flows into the indoor units B and C to be cooled.

Here, control of the first flow control device 9 of the indoor unit performing the cooling operation will be described. FIG. 5 is a flowchart showing the control contents of the opening degree setting means 51 and the first valve opening degree control means 52.

First, a control method of the first flow control device 9 by the opening degree setting means 51 and the first valve opening degree control means 52 will be described. In the first embodiment, the following three minimum openings are set in accordance with the difference temperature Δt ≧ t _a −t ₀ between the target temperature t ₀ preset in the indoor unit and the detection temperature t _a of the suction air temperature detection means 50. Set the degree.

The first minimum valve opening degree Sm ₁ is such that the temperature difference Δt is Δ
When t ≧ t ₂ , the indoor unit is required to have a rated cooling capacity. Therefore, in this case, the opening control according to the outlet superheat SH of the indoor heat exchanger 5 is performed. That is,
The target super heat SHm set in the indoor unit in advance
Of the superheat SH at the outlet and SH △ SH = SH-SHm
When △ SH> 0, it is determined that the refrigerant amount is insufficient, and the opening is increased. Conversely, when △ SH <0, it is determined that the refrigerant amount is excessive,
Decrease the opening. When △ SH = 0, the refrigerant amount is determined to be an appropriate amount, and the opening is maintained.

The second minimum valve opening degree Sm ₂ is such that the temperature difference Δt is t
_In the case of ₁ ≦ Δt <t ₂ , it is set smaller than the first minimum valve opening Sm ₁ . This cooling capacity required of the indoor unit is not required as in the case of Delta] t ≧ t _2, because the may be allowed to flow refrigerant amount in accordance with the load. That is, in this case, since there are many weight refrigerant when going opening control by the first minimum valve superheat amount have only set the opening Sm ₁ of cooling capacity generated in the indoor unit (air-conditioning capacity) And the load
Due to the imbalance between the cooling capacity (required air conditioning capacity) required of the indoor unit and the indoor unit, the indoor unit repeatedly starts and stops, disturbs the stability of the circulation cycle, and is comfortable due to the intermittent blowing of cool air. Sex is impaired. Therefore, as described above, by reducing the opening at a predetermined rate is provided a second minimum valve opening Sm _2, can be set to an opening degree that can safely refrigerant amount commensurate with the load, further, gradual opening The adjustment does not disturb the stability of the circulation cycle.

The third smallest valve opening Sm ₃ of the temperature difference Δt is Δ
If t a <t _1, it is set smaller than the second minimum valve opening. This is because the cooling capacity required for the indoor unit is t ₁ ≦
The load can be further reduced as compared with the case of Δt <t _2.
This is because it is only necessary to flow the amount of the refrigerant according to the above. Note that the concept of the opening degree setting and the opening degree control is the same as in the case of t ₁ ≦ Δt ≦ t ₂ , and therefore the description is omitted.

Further, based on the first embodiment, the first
The control state of the first valve opening degree control means 52 of the flow control device 9 will be described with reference to the flowchart shown in FIG. In step 100, the indoor unit performing the cooling operation determines _a difference temperature Δt = t _a −t ₀ between the preset target temperature t ₀ and the suction air temperature t _a detected by the suction air temperature detection means 50. , Δt ≧ t ₂ , the process proceeds to step 102, where Δt <t ₂
If so, the process proceeds to step 101. If the process proceeds to step 102 sets the minimum valve opening Sm ₁ first, outlet superheat SH of the indoor side heat exchanger 5 at step 105
And SH = SH−SHm, which is the difference between the target superheat SHm and the preset target super heat SHm. If SH> 0, the process proceeds to step 107, where the _first temporary opening degree Sa _-1 is corrected to the previous temporary opening degree Sa _-1 . It calculates the provisional opening degree S _a plus S _1, step 11
Proceed to 2. If △ SH ≦ 0 in step 105, the process proceeds to step 106. If △ SH = 0, in step 108, the temporary opening _Sa is set to the previous temporary opening _{Sa-1 and the} process proceeds to step 112. Further, when △ SH <0 in step 106 calculates the provisional opening degree S _a obtained by subtracting the first opening correction △ S ₁ from the temporary opening S _a-1 in the previous Step 109, the process proceeds to step 112 . In step 112, the provisional opening _Sa and the first minimum valve opening S
comparing m _1, in the case of Sm ₁ below proceeds to step 115, and outputs Sm ₁ as opening S, if Sm ₁ greater than proceeds to step 116, and outputs the S _a as opening S. When the process proceeds to step 101, Δt is t ₁ ≦ Δt <
second minimum valve proceeds to step 103 when the t ₂ opening Sm ₂
Is set, and the routine proceeds to step 110, where the previous temporary opening degree S _{a-1 is set.}
Proceeds from the second opening correction △ S ₂ calculates the provisional opening degree S _a obtained by subtracting the step 113. In step 113, the temporary opening degree S _a
When the second compared the minimum valve opening Sm _2, the process proceeds to step 117 in the case of Sm ₂ below, and outputs the Sm ₂ as opening S, when Sm ₂ larger than the flow proceeds to step 118, S _a
Is output as the opening degree S.

If the condition of step 101 is not satisfied and the routine proceeds to step 104, a third minimum valve opening Sm ₃ is set and the routine proceeds to step 111, where the third temporary valve opening S _{a-1 is} corrected for the third valve opening. △ calculates the provisional opening degree S _a obtained by subtracting the S _3, step 1
Proceed to 14. In step 114, the temporary opening degree _Sa and the third
Comparing the minimum valve opening Sm ₃ of, the process proceeds to step 119 in the case of Sm ₃ below, and outputs Sm ₃ as opening S, if Sm ₃ greater than proceeds to step 120, and outputs the opening degree S.

As described above, according to the first embodiment, the suction air temperature detecting means 50 for detecting the suction temperature of the indoor unit.
And the first flow control device 9 according to a required air conditioning capacity based on a temperature difference between the detected temperature and a preset target temperature.
The opening degree setting means 51 for setting the opening degree of the valve and the first opening degree control means 52 for controlling the opening degree of the first flow control device 9 to the set opening degree are provided. In addition, the amount of refrigerant supplied to the indoor heat exchanger 5 can be appropriately adjusted, the stable operation of the indoor unit can be continued, and the influence on other indoor units, relay units, and heat source units can be suppressed. It is also possible to realize a stable operation of an air conditioner that selectively performs cooling and heating in an indoor unit, and performs cooling in one indoor unit and heating in the other indoor unit at the same time. Then, Δt ≧ t ₂ , t ₂ > Δt according to the required air conditioning capacity based on the temperature difference between the suction temperature of the indoor unit and the target temperature.
Three opening setting control zones of ≧ t ₁ , t ₁ > Δt are provided, and the opening setting means 51 sets the first opening setting zone for each opening setting control zone.
Since the valve opening of the flow control device 9 is set and the first valve opening control means 52 controls the valve opening of the first flow control device 9 to the set valve opening, The opening setting control zone sets the valve opening according to the required air-conditioning capacity, eliminating imbalance between the air-conditioning capacity and the required air-conditioning capacity. there is no disturbing, stable operation Ru can be realized.

Embodiment 2 In the first embodiment, the three-way switching valve 8 is provided so as to be switchably connected to the first connection pipes 6b, 6c, 6d on the indoor unit side and the first connection pipe 6 or the second connection pipe 7. However, in the second embodiment, as shown in FIG. 6, on-off valves such as two solenoid valves 30 and 31 are provided, and the same effect is exerted.

Embodiment 3 FIG. 7 is an overall configuration diagram centering on a refrigerant system of an air conditioner according to Embodiment 3 of the present invention, and FIG.
3 is a configuration diagram showing a control mechanism 55 of the flow control device 9 of FIG.
In the figure, reference numeral 55 denotes a control mechanism for controlling the valve opening of the first flow control device 9, and the control mechanism 55 controls the first flow rate when the indoor unit performing the heating operation (cooling operation) is stopped. The control device 9 includes a fourth valve opening degree control means 56 for setting the opening degree at a predetermined ratio of the opening degree immediately before the stop, and a timing means 57 for measuring the time for maintaining the opening degree at the predetermined ratio.

Here, the operation operation only for cooling or heating, the operation operation mainly for heating, and the operation operation mainly for cooling in the third embodiment operate in the same manner as in the first embodiment.

Next, control of the first flow control device 9 by the control mechanism 55 when the indoor unit performing the heating operation or the cooling operation is stopped will be described. First, when a stop state occurs in an indoor unit performing a heating operation (cooling operation), control is performed such that the opening of the first flow control device 9 does not suddenly enter the closed state. This is because if the condensing capacity (evaporation capacity in cooling operation) of the indoor unit to be stopped suddenly disappears, the high pressure (low pressure in cooling operation) of the air conditioner rises extremely (decreases in cooling operation).
However, this is because failures such as excessive temperature rise (freezing in cooling operation) of the heat exchanger of the indoor unit during another heating operation (cooling operation) or damage to the compressor occur. Therefore, in Embodiment 3, when the indoor unit performing the heating operation (cooling operation) stops, the fourth valve opening control unit 56 sets the opening Pa immediately before the stop to the predetermined coefficient A (cooling operation). In operation, the opening degree P divided by the coefficient B) is output. As a result, the operation state of the air conditioner slightly increases the high pressure (the low pressure decreases in the cooling operation), but the timing P
While holding the other indoor unit, repeater and heat source unit,
Performs autonomous decentralized control for stable operation and suppresses extreme changes in operation. Then, when the time measured by the time measuring means 57 reaches a predetermined time, the fourth valve opening degree control means 56 outputs the close to the first flow control device 9 again, and the indoor unit is stopped.

Further, based on the third embodiment, the first
The control state of the fourth valve opening degree control means 56 of the flow control device 9 will be described with reference to the flowchart shown in FIG. When the stop state occurs in the indoor unit performing the heating operation (cooling operation), the opening degree P obtained by dividing the opening degree Pa immediately before the stop by the coefficient A in step 131 is output to the first flow control device 9. And
Proceed to step 132. In step 132, it is determined whether or not time measurement is in progress. If time measurement is not in progress, the flow advances to step 133 to start time measurement. If time is being measured in step 132,
Proceed to step 134. In step 134, it is determined whether or not the counted time is a predetermined time, and if not, the flow returns to step 132. When it is determined in step 134 that the counted time has reached the predetermined time, the process proceeds to step 135 and outputs the opening degree P = 0.

As described above, according to the third embodiment,
A fourth valve opening control means for setting the valve opening of the first flow control device to a valve opening of a predetermined ratio of the valve opening immediately before the stop when the operating indoor unit is stopped; Since a means for measuring the time for maintaining the valve opening of the ratio is provided, the high-pressure pressure accompanying the extreme decrease in the condensation capacity (evaporation capacity in the cooling operation) when the indoor unit in the heating operation is stopped (In cooling operation, the extreme decrease in low pressure) can be prevented, the effect on other indoor units, repeaters and heat source units can be suppressed. In an air conditioner that simultaneously performs cooling in one indoor unit and heating in the other indoor unit, stable operation can be continued.

Embodiment 4 In the third embodiment, the three-way switching valve 8 is provided so as to be switchably connected to the first connection pipes 6b, 6c, 6d on the indoor unit side and the first connection pipe 6 or the second connection pipe 7. However, in the fourth embodiment, as shown in FIG. 10, on-off valves such as two solenoid valves 30 and 31 are provided and connected so as to be switchable as described above, and the same effect is exerted.

Embodiment 5 FIG. 11 is an overall configuration diagram centering on a refrigerant system of an air conditioner according to Embodiment 5 of the present invention, and FIGS. 12 and 13 are compression only during cooling only and cooling main operation in Embodiment 5 of the present invention, respectively. FIG. 2 is a block diagram and a flowchart showing a capacity control system of the machine.

In the drawing, reference numeral 18 connects the compressor 1 to the four-way valve 2, and fourth pressure detecting means provided in the middle of the pipe which always has a high pressure, and 24 connects the four-way valve 2 to the accumulator 4. Low-pressure saturation temperature detection means provided in the middle of piping
27 is the third flow control device 15 and the second heat exchange unit 16a
A first temperature detecting means provided in the bypass pipe 14 between the first and second temperature detecting means detects an indoor unit inlet subcool amount during the cooling operation from the second pressure detecting means 26 and the first temperature detecting means 27. The subcool amount detecting means 59 is constituted.
58 is a third flow control device inlet subcool amount determining means 6
0 and low pressure saturation temperature target value determining means 61 and capacity control means 6
2 is a compressor capacity control means. This species
For air conditioners, start cooling after prolonged shutdown.
Until the compressor 1 supplies sufficient refrigerant.
Is the first connected to the indoor unit 5 to be operated for cooling.
The amount of refrigerant in the second connection pipes 7b, 7c, 7d is insufficient.
Also, if you try to switch from heating operation to cooling operation,
It is connected to the indoor unit 5 that is going to switch to cooling operation.
In the second connection pipes 7b, 7c, 7d
There is a refrigerant depressurized to a gas-liquid two-phase state. Sa
Furthermore, when the number of cooling operation indoor units is increased, the compressor 1
Supplies the amount of refrigerant corresponding to the number of indoor units for cooling operation
Until the second, which is connected to the indoor unit 5 for cooling operation
The amount of refrigerant in the connection pipes 7b, 7c, 7d is insufficient. Soshi
Because of such a shortage of refrigerant distribution in the second connection pipe,
Refrigerant enters two-phase state, increases flow path resistance and reduces pressure
Will be brought. This pressure drop causes the refrigerant
Prolong the foot condition and delay the rise of cooling capacity
And lead to. In the fifth embodiment, the low pressure saturation temperature
According to the difference between the standard value and the value detected by the low-pressure saturation temperature detecting means 24
When controlling the capacity of the compressor 1 by using
Set the value to the magnitude of the subcool amount at the entrance of the third flow control device 15.
Determined on the basis of the third
To control the capacity of the compressor 1 considering the cool amount
After cooling down for a long time, start cooling operation from heating operation.
When switching to indoor units or when the number of indoor units for cooling operation increases
Thus, the second connection pipe, that is, the third flow control device 15 and
Refrigerant at the inlet of the first flow control device 9 of the cooling indoor unit
Quickly recovers from pressure drop caused by insufficient distribution of water
And quickly improve the shortage of refrigerant in the circuit,
It hastens the rise of the.

Here, the operation operation only for cooling or heating, the operation operation mainly for heating, and the operation operation mainly for cooling in Embodiment 5 are the same as those in Embodiment 1 except for the following operations.

In the case of mainly heating in the simultaneous cooling and heating operation, the capacity of the compressor 1 is controlled so that the pressure detected by the fourth pressure detecting means 18 becomes a predetermined value, and the compressor 1 discharges high-temperature and high-pressure refrigerant gas. Further, in the case of cooling mainly in simultaneous cooling and heating operation, the compressor 1 is provided with a low-pressure saturation temperature detecting means 2.
The capacity is controlled so that the detected temperature of 4 becomes a predetermined value, and the refrigerant gas is discharged.

Next, the capacity control of the compressor 1 in the case of only the cooling operation and in the case of mainly cooling in the simultaneous cooling and heating operation will be described with reference to FIGS.

In step 140, it is determined whether the current low pressure saturation temperature target value is a normal value or a special value lower than the normal value. In step 141, SC <SC based on the third flow control device inlet subcool amount (described as SC).
If the first predetermined value has continued for a predetermined continuous time or more, the process proceeds to step 143; otherwise, the process proceeds to step 144. In step 143, the low-pressure saturation temperature target value is set to a special value that is lower than the normal value and is equal to or lower than the low-pressure saturation temperature due to the low-pressure drop caused by the small SC. In step 144, the low-pressure saturation temperature target value is kept at the normal value. In step 142, S
C> second predetermined value (a value larger than the first predetermined value is set)
If is accumulated for a predetermined integration time or longer, the process proceeds to step 145; otherwise, the process proceeds to step 146. In step 145, the low pressure saturation temperature target value is set to a normal value. Step 146
Then, the low pressure saturation temperature target value is kept at a special value lower than the normal value.

After the low pressure saturation temperature target value is determined as described above, it is compared with the detected temperature of the low pressure saturation temperature detecting means 24 in steps 147 and 151. If value = detection value, go to step 149; if target value <detection value, go to step 1
Go to 50. In step 148, the compressor capacity is reduced by a predetermined value. In step 149, the compressor capacity is not changed. In step 150, the compressor capacity is increased by a predetermined value.

As described above, according to the fifth embodiment,
There use an inlet subcool amount of the third flow controller 15 as a representative value of the cooling indoor unit inlet subcool amount, the low-pressure saturation temperature goal as capacity control target value of the compressor 1 when the sub Bukuru amount is equal to or less than a predetermined value have any value so as to lower the predetermined value
You. Then, the low-pressure saturation temperature detection is performed by the capacity control unit 62.
According to the difference between the detection value of the output means 24 and the low pressure saturation temperature target value.
Thus, the capacity of the compressor 1 is controlled. Therefore, when the cooling is started after a long stoppage , when switching from the heating operation to the cooling operation, when the number of indoor units for the cooling operation is increased , the second connection is performed.
Insufficient distribution of the refrigerant in the connecting pipes 7b, 7c, 7d
Flow control device 15 and first flow control device for cooling indoor unit
9 is detected as a decrease in the subcooling amount at the entrance
The saturation temperature target value is quickly reduced, and the capacity of the compressor 1 is reduced.
Will be increased. Then, the supply amount of the refrigerant from the compressor 1 increases.
Then, the movement of the refrigerant is accelerated, and the refrigerant is supplied to the second connection pipe 7.
b, 7c, and 7d. As a result, the refrigerant shortage state of the circuit is promptly improved, and the rise of the cooling capacity can be accelerated.

In the above-described fifth embodiment, an example of the multi-room heat pump air conditioner has been described, but it goes without saying that the present invention can be applied to a one-to-one heat pump and a refrigeration unit.

Embodiment 6 FIG. 14 is an overall configuration diagram centering on a refrigerant system of an air conditioner according to Embodiment 6 of the present invention. In the figure, 2
Reference numeral 8 denotes a fifth flow control device provided in a pipe connecting a lower part of the accumulator 4 and an outlet pipe of the accumulator 4, and 63 includes a second pressure detecting means 26 and a first temperature detecting means 27. A fifth valve opening control unit that controls the opening of the fifth flow control device 28 in accordance with the subcool amount detected by the subcool amount detection unit 59 of the indoor unit inlet-side refrigerant.

Here, the operation operation only for cooling or heating, the operation operation mainly for heating, and the operation operation mainly for cooling in the sixth embodiment operate in the same manner as in the fifth embodiment.

Next, the opening degree control of the fifth flow control device 28 in the case of only the cooling operation and in the case of the cooling-maintenance simultaneous cooling-main operation will be described with reference to FIGS. FIG. 15 is a block diagram of the control. Normal,
The opening degree of the fifth flow control device 28 is set to a compressor operating frequency 64
A predetermined opening is set by the fifth flow control device reference opening determining means 66 based on the detected temperature of the outside air temperature detecting means 65 and the detected temperature. In addition, based on the detected pressure of the second pressure detecting means 26 and the temperature detected by the first temperature detecting means 27, a third flow rate control device inlet subcool amount determining means 60 is used as a representative value of the cooling indoor unit inlet subcool amount. [Subcool amount]
= [Saturation temperature of detected pressure]-[detected temperature] to find the third flow control device inlet subcool amount. Then, according to the subcool amount, the fifth flow control device opening determining means 67 determines whether to use the reference opening or a special opening having an opening larger than the reference opening. The opening degree of the control device 28 is controlled.

FIG. 16 is a control flowchart. In step 152, it is determined whether the opening of the fifth flow control device 28 is the reference opening or the special opening. If the opening is the reference opening, the process proceeds to step 153. If the opening is the special opening, the process proceeds to step 154.
In step 153, the process proceeds to step 155 if SC <the first predetermined value has continued for a predetermined continuous time or more based on the third flow control device inlet subcool amount (described as SC), otherwise to step 156. . In step 155, the opening of the fifth flow control device 28 is set to the special opening.
In step 156, the opening of the fifth flow control device 28 is kept at the reference opening. In step 154, if SC> the second predetermined value (set to a value larger than the first predetermined value 2) has been integrated for the predetermined integration time or longer, the process proceeds to step 157; otherwise, the process proceeds to step 158. In step 157, the opening of the fifth flow control device 28 is set as the reference opening.
In step 158, the opening of the fifth flow control device 28 is kept at the special opening.

As described above, according to the sixth embodiment, the subcool amount is used as the representative value of the inlet subcool amount of the cooling indoor unit when the subcool amount is equal to or smaller than the first predetermined value. 5, the opening degree of the flow control device 28 is set to a special opening degree larger than the reference opening degree, at the time of cooling start after a long stop, at the time of switching from the heating operation to the cooling operation, or at the time of increasing the number of indoor units of the cooling operation. At the entrance of the third flow control device 15 and the first flow control device 9 of the cooling indoor unit, the refrigerant is in a two-phase state due to insufficient distribution of the refrigerant, the flow path resistance increases, and the low pressure further decreases. In response to the accompanying decrease in the amount of circulating refrigerant, the liquid refrigerant accumulated in the accumulator 4 is supplied to the compressor 1 to increase the amount of circulating refrigerant, improve the shortage of the refrigerant in the refrigerant circuit, and accelerate the rise of the cooling capacity. Can be.

In the sixth embodiment, the example of the multi-room heat pump air conditioner has been described.
It goes without saying that the present invention can be applied to a one-to-one heat pump and a chiller.

Embodiment 7 FIG. 17 is an overall configuration diagram centered on a refrigerant system of an air conditioner according to Embodiment 7 of the present invention. In the figure, 2
Numeral 0 denotes a heat source side blower with a variable air flow, and numeral 68 connects a compressor discharge side high pressure gas pipe 69 and an accumulator inlet pipe 70 connecting the four-way valve 2 and the accumulator 4 via a flow regulator 71. 72, an opening / closing valve of the bypass circuit 68, and 73, an indoor unit inlet subcool amount during the cooling operation detected by the subcool amount detecting means 59 including the second pressure detecting means 26 and the first temperature detecting means 27. Is a sixth valve opening control means for controlling the valve opening of the on-off valve 72 of the bypass circuit 68 on the basis of the third flow control device inlet subcool amount. It comprises a decision means 60 and a bypass circuit opening / closing valve opening / closing control means 74.

Next, the operation of the seventh embodiment will be described. The operation operation only for cooling or heating, the operation operation mainly for heating, and the operation operation mainly for cooling in Embodiment 7 operate in the same manner as in Embodiment 5 except for the following operation. The operation different from that of the fifth embodiment is that the refrigerant flowing into the heat source unit side heat exchanger 3 exchanges heat with the air blown by the heat source unit side blower 20 having a variable air volume to condense and liquefy or evaporate and gasify. It is a point to do.

Next, the open / close control of the open / close valve 72 of the bypass circuit 68 in the case of only the cooling operation and in the case of cooling mainly in the simultaneous cooling / heating operation will be described with reference to FIGS.
This will be described in Section 9. FIG. 18 is a block diagram of the control. Second
Pressure detected by the pressure detecting means 26 and the first temperature detecting means 2
From the detected temperature of 7 as the representative value of the subcooling amount at the inlet of the cooling indoor unit, the third flow rate control device inlet subcooling amount determining means 60 sets [subcooling amount] = [saturation temperature of detection pressure] − [detection temperature]. The subcool amount at the inlet of the flow control device of No. 3 is obtained. And according to the subcool amount,
The on-off valve 72 of the bypass circuit 68 is controlled by the on-off valve on-off control means 74 of the on-off valve 72 of the bypass circuit 68.
Open / close control. At this time, the flow rate of the refrigerant flowing through the bypass circuit 68 is adjusted by the flow rate controller 71, and the return of the excessive refrigerant to the accumulator 4 is controlled.

FIG. 19 is a control flowchart. At step 159, it is determined whether the on-off valve 72 of the bypass circuit 68 is currently closed or open.
If it is in the open state, the process proceeds to step 161. In step 160, if SC <the first predetermined value has continued for a predetermined continuous time or more based on the subcooling amount (described as SC) at the entrance of the third flow control device, the flow proceeds to step 162; move on. In step 162,
The on-off valve 72 of the bypass circuit 68 is opened. Step 16
In 3, the on-off valve 72 of the bypass circuit 68 is kept closed. In step 161, if SC> second predetermined value (set to a value larger than the first predetermined value) is integrated for a predetermined integration time or more, the process proceeds to step 164;
Go to 5.

In step 164, the on-off valve 72 of the bypass circuit 68 is closed. In step 165, the on-off valve 72 of the bypass circuit 68 is kept open.

As described above, according to the seventh embodiment, the third sub-cooling amount is used as the representative value of the sub-cooling amount at the inlet of the cooling indoor unit, and the sub-cooling amount is equal to or less than the second predetermined value. By opening the on-off valve 72 at 68, the third flow control device 15 and the cooling room can be used, for example, when starting cooling after a long stoppage, when switching from heating operation to cooling operation, or when increasing the number of indoor units in cooling operation. At the inlet of the first flow control device 9 of the machine, the refrigerant is in a gas-liquid two-phase state due to insufficient distribution of the refrigerant, the flow path resistance increases, and the low pressure side pressure decreases. The bypass increases the low-pressure side pressure and evaporates the liquid refrigerant stored in the accumulator 4 by the high-pressure gas, thereby increasing the refrigerant circulation amount, improving the refrigerant shortage state of the circuit, and increasing the cooling capacity. Ri can hasten the.

In the seventh embodiment, the example of the multi-room heat pump air conditioner has been described.
It goes without saying that the present invention can be applied to a one-to-one heat pump and a chiller.

Reference Example 1 FIG. 20 is an overall configuration diagram centering on the refrigerant system of the air-conditioning apparatus according to Embodiment 1 of the present invention. In the drawing, reference numeral 37 denotes a liquid drainage pipe having one end connected to the gas-liquid separator 12 and the other end connected to the first connection pipe 6, and 38 denotes a gas-liquid separator 12 of the liquid drainage pipe 37 and the first connection pipe 6. A flow control device 39 is provided between the liquid discharge pipe 37 and the sixth flow control device 38, and connects the gas-liquid separation device 12 to the first branch portion 10. This is a fourth heat exchange section that performs heat exchange between the first heat exchanger and the second heat exchanger. 46 is a third pressure detecting means attached to the pipe connecting the first connection pipe 6 and the first branch section 10, and 82 is attached to the outlet side of the fourth heat exchange section 39 on the liquid drain pipe 37 side. Fifth temperature detecting means. Reference numeral 81 denotes first stop time counting means 84 for counting the time during which the indoor unit is stopped during operation of the compressor 1, which will be described later, and first control means for determining and controlling the opening and closing of the three-way switching valve 8 based on the stop time. 87 and a first control device.

Here, the operation of the reference example 1 in the case of only the cooling operation, the case of the heating operation only, and the case of the heating-mainly in the simultaneous cooling and heating operation operates in the same manner as in the first embodiment.

Next, the operation of the simultaneous cooling and heating operation mainly for cooling will be described. When the liquid surface, which is the boundary surface between the gaseous refrigerant and the liquid refrigerant separated by the gas-liquid separator 12, is below the drainage pipe 37 of the gas-liquid separator 12, the gaseous refrigerant is removed from the liquid drainage pipe 37. And the pressure is reduced to a low pressure by the sixth flow control device 38. Since the inlet of the sixth flow control device 38 is in a gas state, the amount of the refrigerant flowing through the sixth flow control device 38 is small. Therefore, the drainage pipe 37
Is exchanged with the high-pressure gaseous refrigerant flowing into the first branch 10 from the gas-liquid separator 12 in the fourth heat exchange section 39 to become a low-pressure superheated gas, It flows into the connection pipe 6. Conversely, when the liquid surface, which is the boundary between the gaseous refrigerant and the liquid refrigerant separated by the gas-liquid separator 12, is above the liquid drain pipe 37 of the gas-liquid separator 12, the liquid refrigerant is drained. After flowing into the pipe 37, the pressure is reduced to a low pressure by the sixth flow control device 38. Since the inlet of the sixth flow control device 38 is in the liquid state, the amount of the refrigerant flowing through the sixth flow control device 38 is larger than that in the case where the inlet is in the gaseous state. For this reason, the refrigerant flowing through the liquid drain pipe 37 is supplied to the fourth heat exchange unit 3.
In 9, even if heat exchange is performed with the high-pressure gaseous refrigerant flowing into the first branch portion 10 from the gas-liquid separation device 12, the refrigerant does not become a low-pressure superheated gas, but is connected to the first connection pipe 6 in a two-phase state. Inflow. The overheating state of the low-pressure refrigerant that has exchanged heat in the fourth heat exchange unit 39 is determined based on the pressure detected by the third pressure detection unit 46 and the temperature detected by the fifth temperature detection unit 82. Other operations are the same as those in the first embodiment.

In the first embodiment, the three-way switching valve 8 is provided to switch between the first connection pipe 6b, 6c, 6d on the indoor unit side and the first connection pipe 6 or the second connection pipe 7. The same operation and effect can be obtained by providing two solenoid on-off valves, such as 30 and 31, instead of the three-way switching valve 8, and connecting them in a switchable manner as described above.

Further, in the cooling operation of the first embodiment, the first flow rate connected to the indoor unit D when the two indoor units B and C are cooling and the indoor unit D is stopped. Control of the control device 9 and the three-way switching valve 8 will be described.
When the indoor unit D is stopped, the first flow control device 9 connected to the indoor unit D is closed, and the three-way switching valve 8 is connected to the first port 8.
a, the second port 8b and the third port 8c are all closed, but due to the leakage of the first flow control device 9 and the three-way switching valve 8, the refrigerant flows into the first connection pipe 6d on the indoor unit side. And it flows into the indoor unit side heat exchanger 5, condenses, and accumulates as a liquid refrigerant. If the accumulated liquid refrigerant is left, the refrigerant cycle becomes inadequate as a refrigeration cycle. Therefore, when the compressor 1 is operating in the cooling operation, the indoor unit D stops for more than the first set time set in advance. Then, the second port 8b and the third port 8c of the three-way switching valve 8 of the indoor unit D are opened and the first port 8a is closed for the second set time set in advance. Thereby, by connecting the indoor heat exchanger 5 and the first connection pipe 6d on the indoor unit side to the first connection pipe 6 via the first branch portion 10, the indoor heat exchanger 5 and the first connection pipe 6d are connected to each other. By lowering the pressure of the first connection pipe 6d on the indoor unit side, the liquid refrigerant that has flowed into and accumulated in the indoor heat exchanger 5 and the first connection pipe 6d on the indoor unit side is pumped down. Branch 1 of 1
0, the liquid refrigerant flowing out to the first connection pipe 6 is collected.

Hereinafter, description will be made with reference to FIGS. 21, 22 and 23. FIG. 21 is a configuration diagram for controlling the three-way switching valve 8 of the first embodiment. The operation switches 85b, 85c, and 85d of the indoor units B, C, and D and the cooling / heating switching switches 86b, 86c, and 86d of the indoor units B, C, and D are used to operate the indoor units B during the compressor operation in the cooling operation. , C, D are stopped by the first stop time counting means 84, and the first control means 87 determines and controls the opening and closing of the three-way switching valve 8 from the stop time. FIG. 22 is a circuit diagram showing an example of the electrical connection of the first embodiment. Reference numeral 88 denotes a microcomputer in the first control device 81, which has a CPU
89, a memory 90, an input circuit 91, and an output circuit 92. R _{1 to} R ₆ are operation switches 85b and 85, respectively.
c, 85d and cooling / heating switch 86b, 8
6 c and 86 d are resistors in series, and the output is supplied to the input circuit 91. Control transistors Tr ₁ , Tr ₂ , Tr ₃ for controlling the opening and closing of the three-way switching valve 8 are connected to an output circuit 92 via resistors R _{7 to} R ₉ .

FIG. 23 is a flowchart showing a program for controlling the opening of the three-way switching valve 8 stored in the memory of the microcomputer 88. In step 180, it is determined whether or not the stop time is equal to or longer than a first set time set in advance, and if it is, the process proceeds to step 182, and if not, the process proceeds to step 181. In step 181, the first port 8a, the second port 8b, and the third port 8c of the three-way switching valve 8 are closed. In step 182, the second port 8 of the three-way switching valve 8
b and the third port 8c are open, and the first port 8a is closed. In step 183, the second port 8b of the three-way switching valve 8 and the third port 8b
It is determined whether the time after opening the mouth 8c and closing the first mouth 8a is equal to or longer than a second set time set in advance. In step 184, the first port 8a, the second port 8b, and the third port 8c of the three-way switching valve 8 are closed. Although the control of the three-way switching valve 8 has been described in the case of the cooling operation, the same operation and effect can be obtained also in the case of the heating operation, the heating main body, and the cooling main body.

According to the first embodiment, the first stop time counting means 84 for counting the stop time of the indoor unit in which the compressor 1 is stopped during operation, and the first stop time counting means 84 set in advance.
And the first control means 87 for switching the three-way switching valve 8 so as to connect the indoor unit that has stopped for more than the set time to the second connection time set in advance to the first connection pipe 6. Liquid refrigerant accumulated in the indoor heat exchanger of the stopped indoor unit is collected, and the refrigeration cycle does not run out of refrigerant even if the number of operating indoor units changes. Accordingly, it is possible to prevent the discharge temperature of the compressor from rising, and to prevent a decrease in the reliability of the compressor due to the rise in the discharge temperature of the compressor.

Reference Example 2 FIG. 24 is an overall configuration diagram centering on a refrigerant system of an air conditioner according to Embodiment 2 of the present invention. In the figure, reference numeral 83 denotes second stop time counting means 93 for counting the time during which the indoor unit is stopped during operation of the compressor 1, which will be described later. This is a second control device including second control means 94 for controlling opening and closing of the first flow control device 9.

Here, in the case of only the cooling operation, in the case of only the heating operation, and in the simultaneous cooling and heating operation, the operation of the second embodiment in the case of the heating main body and the cooling main body operates in the same manner as in the first embodiment.

Next, in the heating operation of Reference Example 2, the first flow rate connected to the indoor unit D when the two indoor units B and C are heating and the indoor unit D is stopped. Control of the control device 9 and the three-way switching valve 8 will be described. When the indoor unit D is stopped, the first flow control device 9 connected to the indoor unit D is closed, and the three-way switching valve 8 is connected to any one of the first port 8a, the second port 8b, and the third port 8c. Is closed,
Due to the leakage of the first flow control device 9 and the three-way switching valve 8,
The refrigerant flows into the first connection pipe 6d on the indoor unit side and into the indoor heat exchanger 5, condenses, and accumulates as a liquid refrigerant. If the accumulated liquid refrigerant is left, the refrigerant cycle will be in a shortage state as a refrigeration cycle. Therefore, while the compressor 1 is operating in the heating operation, the indoor unit D has stopped for more than the third set time set in advance. If the fourth preset
, The first flow control device 9 of the indoor unit D is opened, the first port 8a and the third port 8c of the three-way switching valve 8 are opened, and the second port 8b is closed. As a result, the high-temperature and high-pressure refrigerant gas flows from the first branch section 10 into the first indoor unit-side first connection pipe 6 d and into the indoor unit heat exchanger 5, and accumulates in the second indoor unit-side liquid refrigerant. From the connection pipe 7d to the second branch 1
1 and collects the accumulated liquid refrigerant.

Hereinafter, description will be made with reference to FIGS. 25, 26 and 27. FIG. 25 shows the first flow control device 9 of the second embodiment.
FIG. 2 is a configuration diagram for controlling a three-way switching valve 8. Operation switches 85b, 85c, 85d of each indoor unit B, C, D
And the time when the indoor units B, C, and D are stopped during the compressor operation in the heating operation from the cooling / heating switching switches 86b, 86c, and 86d of the indoor units B, C, and D are second stop times. The counting is performed by the counting means 93, and the opening degree of the first flow control device 9 and the opening and closing of the three-way switching valve 8 are determined and controlled by the second control means 94 from the stop time. FIG. 26 is a circuit diagram showing an example of the electrical connection of the second embodiment. Reference numeral 95 denotes a microcomputer in the control device 83,
6, a memory 97, an input circuit 98, and an output circuit 99. Each R ₁₁ to R ₁₆ operating switches 85b, 85
c, 85d and cooling / heating switch 86b, 8
6 c, 86 d is a resistor in series, and its output is provided to the input circuit 98. The control transistors Tr ₄ and Tr ₅ for controlling the opening degree of the first flow control device 9 include resistors R ₁₇ and R ₁₈
And transistors Tr ₆ , Tr ₇ , Tr ₈ for controlling the opening and closing of the three-way switching valve 8 are connected to the output circuit 99 via resistors R ₁₉ , R ₂₀ , R ₂₁ .

FIG. 27 is a flowchart showing an opening degree control program of the three-way switching valve 8 and the first flow control device 9 stored in the memory 97 of the microcomputer 95. In step 185, it is determined whether or not the stop time is equal to or longer than a third set time set in advance. If not, the process proceeds to step 187;
Proceed to. In step 186, the first flow control device 9 is closed, and the first port 8a, the second port 8b, and the third port 8 of the three-way switching valve 8 are closed.
Close c. In step 187, the first flow control device 9 is opened, and the first port 8a and the third port 8c of the three-way switching valve 8 are opened.
Is open and the second port 8b is closed. In step 188, the first flow control device 9 is opened, and the first port 8 of the three-way switching valve 8 is opened.
It is determined whether the time from opening the third port 8c and the third port 8c and closing the second port 8b is equal to or longer than a preset fourth set time. Proceed to. In step 189, the first flow control device 9 is closed, and the first port 8a, the second port 8b, and the third port 8c of the three-way switching valve 8 are closed. In the case of the heating operation, the control of the first flow control device 9 and the three-way switching valve 8 has been described. However, even in the case of mainly heating and cooling,
A similar effect can be obtained. Also, in the case where the electromagnetic on-off valves 30 and 31 are provided instead of the three-way switching valve 8, the same operation and effect as described above can be obtained.

According to the second embodiment, the second stop time counting means 93 for counting the stop time of the indoor unit in which the compressor 1 is stopped while the compressor 1 is operating, and the third stop time counting means 93 set in advance.
The three-way switching valve 8 is switched so that the indoor unit that has stopped for more than the set time is connected to the second connection pipe 7 for the fourth set time that has been set in advance, and the first indoor unit that has stopped has been stopped. Is provided with the second control means 94 for controlling the flow rate control device 9 to open. Therefore, the high pressure side and the low pressure side communicate with each other, and the indoor unit heat exchanger of the indoor unit stopped by the differential pressure The liquid refrigerant can be quickly expelled, and as a result, even if the number of operating indoor units changes, the refrigeration cycle does not become in a state of refrigerant shortage, and it is possible to prevent the discharge temperature of the compressor from rising due to the refrigerant shortage operation. It is possible to prevent a decrease in the reliability of the compressor due to an increase in the discharge temperature of the compressor.

[0096]

Since the present invention is configured as described above, the following effects can be obtained.

According to the first aspect of the present invention, a compressor,
One heat source unit having a four-way valve and a heat source unit side heat exchanger is connected to a plurality of indoor units having an indoor side heat exchanger and a first flow control device by piping, and a plurality of heat source units are connected from the heat source unit. In the air conditioner that supplies a refrigerant to the indoor unit and performs the cooling / heating operation, the intake air temperature detecting unit that detects the intake air temperature of each of the plurality of indoor units and the valve opening of the first flow control device are set. Opening degree setting means; and first valve opening degree control means for controlling the valve opening degree of the first flow rate control device to the set valve opening degree. A plurality of opening setting control zones corresponding to the required air-conditioning capacity based on a difference from the set target temperature are provided, a minimum valve opening is set for each control zone, and a valve of the first flow control device is set up to the minimum valve opening. The opening degree is adjusted and controlled at a predetermined ratio, so that it is supplied to the indoor heat exchanger. The amount of refrigerant can be adjusted appropriately, the stable operation of the indoor unit can be continued, and the influence on other indoor units and heat source units can be suppressed. An air conditioner capable of simultaneously performing cooling in the unit and heating in the other indoor unit is obtained.
In addition, the opening degree control zone sets the valve opening degree according to the required air conditioning capacity, eliminating imbalance between the air conditioning capacity and the required air conditioning capacity, reducing the repetition of operation and stoppage of the air conditioner, and reducing the circulation cycle. Stability is not disturbed, and stable operation is realized. Further, the required air-conditioning capacity can be reliably ensured without causing a shortage of the refrigerant flow rate.

[0098]

According to a second aspect of the present invention, a compressor,
One heat source unit having a four-way valve and a heat source unit side heat exchanger, and a plurality of indoor units having an indoor side heat exchanger and a first flow control device are connected by piping, and a plurality of heat source units are connected from the heat source unit. In the air-conditioning apparatus that performs the cooling and heating operation by supplying the refrigerant to the indoor unit, when the indoor unit is stopped, since the valve opening of the first flow control device is maintained at the predetermined opening for a predetermined time and then closed, An extreme increase in high pressure due to an extreme decrease in condensing capacity when the indoor unit for heating operation is stopped is prevented, and a decrease in low pressure due to an extreme decrease in evaporative capacity when the indoor unit for cooling operation is stopped. Extreme decline is prevented, the effect on other indoor units and heat source units can be suppressed, cooling and heating can be selectively performed for multiple indoor units, and cooling is performed for one indoor unit and heating is performed simultaneously for the other indoor unit. An air conditioner that can be performed is obtained.

According to the third aspect of the present invention, the second aspect
In the invention, when the indoor unit is stopped, a fourth valve opening control means for setting the valve opening of the first flow control device to a predetermined ratio of the valve opening immediately before the stop, and a first flow rate The control device is provided with time-measuring means for measuring the time during which the valve opening degree is maintained at a predetermined ratio. The degree is maintained at a predetermined valve opening degree by the fourth valve opening degree control means, during which other indoor units and heat source units perform autonomous distributed control to stable operation,
Extreme driving changes are suppressed.

According to a fourth aspect of the present invention, a compressor,
One heat source unit having a four-way valve and a heat source unit side heat exchanger, and a plurality of indoor units having an indoor side heat exchanger and a first flow control device are connected by piping, and a plurality of heat source units are connected from the heat source unit. A cooling operation is performed by supplying a refrigerant to the indoor unit of the compressor, and a subcool amount detecting means for detecting an indoor unit inlet subcool amount during the cooling operation, and a compressor based on the subcool amount detected by the subcool amount detecting means. A capacity control target value is determined, and in the air conditioner including compressor capacity control means for controlling the capacity of the compressor based on the capacity control target value, the heat source unit and the plurality of indoor units are connected to the first and the plurality of indoor units. A first valve device that is connected via a second connection pipe and has a valve device for switchably connecting one of the indoor heat exchangers of the plurality of indoor units to the first connection pipe or the second connection pipe. Branch and the other of the indoor heat exchangers of multiple indoor units Is connected via a first flow control device, and a second branch portion formed by connecting the second connecting pipe through a second flow control device, and a second branch portion first
And a second connection pipe provided on the downstream side of the third flow control device and provided on the side of each indoor unit in the second branch section. And a second heat exchange section for exchanging heat between the junction section and the bypass pipe, and a pipe connecting the four-way valve, the accumulator, and the compressor in the order of connecting the four-way valve and the accumulator. Low pressure saturation temperature detecting means, a second pressure detecting means disposed between the first flow control device and the second flow control device, and a second pressure detecting device upstream of the third flow control device. And a first temperature detecting means disposed between the flow control device and the second heat exchange section, wherein the subcool amount detecting means includes a second pressure detecting means and a first temperature detecting means. Wherein the compressor capacity control means is configured to detect the saturation temperature of the pressure detected by the second pressure detection means. And a third flow control device inlet subcool amount determining means for determining an indoor unit inlet subcool amount from a difference between the detected temperature and the first temperature detecting means. A low-pressure saturation temperature target value determining means for determining a low-pressure saturation temperature target value as a capacity control target value based on the indoor unit inlet subcool amount, and according to a difference between the low-pressure saturation temperature target value and the detection temperature of the low-pressure saturation temperature detection means. Capacity control means for controlling the capacity of the compressor, and the capacity of the compressor is controlled in accordance with the amount of indoor unit inlet subcooling during the cooling operation to ensure a sufficient refrigerant circulation amount. Refrigerant shortage state at the time of cooling start after time stop, at the time of switching from heating operation to cooling operation, or at the time of increasing the number of indoor units for cooling operation is improved, and the rise of cooling capacity is accelerated. Bets can be, selectively heating and cooling a plurality of indoor units, and, in one of the indoor units cool the air conditioner can be obtained which can perform heating at the same time in the other indoor unit. Further, a sufficient amount of the refrigerant circulating at the inlet of the indoor unit in the cooling operation is ensured, and the low pressure that occurs due to the two-phase state due to the insufficient distribution of the refrigerant and the increase in the flow path resistance can be suppressed. Further, the subcool amount at the entrance of the indoor unit in the cooling operation can be reliably detected. Furthermore, the capacity of the compressor is controlled in accordance with the subcool amount at the inlet of the indoor unit in the cooling operation, and the refrigerant shortage state of the circuit is improved.

[0102]

[0103]

[0104]

According to the fifth aspect of the present invention, a compressor,
One heat source unit having a four-way valve, a heat source unit side heat exchanger and an accumulator, and a plurality of indoor units having an indoor side heat exchanger and a first flow control device are connected by piping, and from the heat source unit In an air conditioner that performs cooling and heating operation by supplying a refrigerant to a plurality of indoor units, a fifth flow control device provided in a piping path connecting a lower part of the accumulator and an outlet pipe of the accumulator, Subcool amount detection means for detecting an indoor unit entrance subcool amount, and fifth valve opening control means for controlling the valve opening of the fifth flow control device according to the subcool amount detected by the subcool amount detection means. The liquid refrigerant stored in the accumulator is supplied to the compressor according to the indoor unit inlet subcool amount during the cooling operation to ensure a sufficient refrigerant circulation amount. When switching from the cooling operation to the cooling operation, or when the number of cooling operation indoor units is increased, the refrigerant shortage state is improved, the rise of the cooling capacity can be accelerated, the cooling and heating can be selectively performed by a plurality of indoor units, and An air conditioner capable of simultaneously performing cooling with one indoor unit and heating with the other indoor unit is obtained. Also, by controlling the valve opening of the fifth flow control device in accordance with the subcooling amount at the inlet of the indoor unit for the cooling operation, the refrigerant accumulated in the accumulator is supplied to the compressor to increase the refrigerant circulation amount. In addition, the refrigerant shortage state of the circuit can be improved.

[0106]

According to the sixth aspect of the present invention, the fifth aspect
In the invention, the heat source unit and the plurality of indoor units are connected via the first and second connection pipes, and one of the indoor heat exchangers of the plurality of indoor units is connected to the first connection pipe or the second connection pipe. A first branch unit having a valve device that is switchably connected to the connection pipe of the first unit; and a first branch unit connected to the other of the indoor heat exchangers of the plurality of indoor units via the first flow control device, and A second branch connected to the second connection pipe via the second flow control device, wherein the subcool amount detecting means is provided between the first flow control device and the second flow control device. Since it is composed of the second pressure detecting means and the first temperature detecting means provided, the subcool amount at the inlet of the indoor unit in the cooling operation can be reliably detected.

According to the seventh aspect of the present invention, the sixth aspect
In the invention, the second branch portion and the first connection pipe are connected to each other, and a bypass pipe provided with a third flow control device and a second branch provided downstream of the third flow control device. A second heat exchanging section for exchanging heat between the junction of the second connecting pipes on the side of each indoor unit in the section and the bypass pipes, wherein the first temperature detecting means is provided in the third flow control device. The fifth valve opening control means is disposed between the third flow control device and the second heat exchange section on the upstream side, and the fifth valve opening degree control means determines the saturation temperature of the pressure detected by the second pressure detection means and the first temperature. A third flow control device inlet subcool amount determining means for determining an indoor unit inlet subcool amount based on a difference from a temperature detected by the temperature detecting device; and a reference valve of the fifth flow control device based on the operating frequency of the compressor and the outside air temperature. A fifth flow control device reference opening determining means for determining the opening;
The fifth flow control device determines the valve opening of the fifth flow control device to be the reference valve opening or the special valve opening based on the indoor unit entrance subcool amount determined by the flow control device entrance subcool amount determining means. Because of the opening degree determining means, the refrigerant accumulates in the accumulator due to insufficient distribution of the refrigerant at the inlet side of the third flow control device and the first flow control device of the indoor unit in the cooling operation. The refrigerant in the circuit can be supplied to the compressor to increase the amount of circulating refrigerant, thereby improving the refrigerant shortage state in the circuit.

According to the eighth aspect of the present invention, a compressor,
One heat source unit having a four-way valve, a heat source unit side heat exchanger and an accumulator, and a plurality of indoor units having an indoor side heat exchanger and a first flow control device are connected by piping, and from the heat source unit A refrigerant is supplied to a plurality of indoor units to selectively perform cooling / heating operation for each of the plurality of indoor units, and a pipe connecting an accumulator and a four-way valve is connected to a discharge-side high-pressure gas pipe of a compressor. A bypass circuit, a subcool amount detecting means for detecting an indoor unit entrance subcool amount during the cooling operation, and a sixth control for controlling a valve opening of the bypass circuit in accordance with the indoor unit entrance subcool amount detected by the subcool amount detection unit. In an air conditioner provided with a valve opening control means, a heat source unit and a plurality of indoor units are connected via first and second connection pipes, and an indoor heat exchanger of the plurality of indoor units is connected. One is the first connection pipe or the second Connected connected to the first branch portion pipe with a valve device for switching and connected to, via a first flow control device to the other plurality of the indoor unit indoor heat exchanger,
A second branch portion connected to the second connection pipe via the second flow control device; a second branch portion connected to the first connection pipe; and a third flow control device. Is provided downstream of the third flow control device and provided at the downstream side of the third flow control device, and performs heat exchange between the junction of the second connection pipe on each indoor unit side in the second branch and the bypass pipe. A second heat exchange section, a second pressure detecting means disposed between the first flow rate control device and the second flow rate control device, and a third pressure upstream side of the third flow rate control device. A first temperature detecting means disposed between the flow control device and the second heat exchanging unit, wherein the subcool amount detecting means comprises a second pressure detecting means and a first temperature detecting means; The sixth valve opening degree control means determines the difference between the saturation temperature of the pressure detected by the second pressure detection means and the temperature detected by the first temperature detection means. A third flow control device inlet subcool amount determining means for determining an indoor unit inlet subcool amount from the air conditioner, and bypass circuit valve opening / closing control means for controlling a valve opening of the bypass circuit based on the indoor unit inlet subcool amount. Therefore, high-pressure gas is bypassed to the low-pressure side according to the subcooling amount at the inlet of the indoor unit for cooling operation, increasing the low-pressure side pressure, and evaporating the liquid refrigerant accumulated in the accumulator to increase the refrigerant circulation amount. When the cooling is started after a long stoppage, when the cooling operation is switched from the heating operation to the cooling operation, or when the number of the indoor units in the cooling operation is increased, the refrigerant shortage state is improved, and the rise of the cooling capacity can be accelerated. An air conditioner capable of selectively performing cooling and heating in an indoor unit and simultaneously performing cooling in one indoor unit and heating in the other indoor unit is obtained. That. Further, the subcool amount at the entrance of the indoor unit in the cooling operation can be reliably detected. Furthermore, the low pressure side pressure is increased by bypassing the high pressure gas to the low pressure side in response to the shortage of the distribution amount of the refrigerant at the inlet side of the third flow control device and the first flow control device of the indoor unit in the cooling operation. Further, the liquid refrigerant accumulated in the accumulator is evaporated by the high-pressure gas to increase the amount of circulating refrigerant, thereby improving the refrigerant shortage state in the circuit.

[0110]

[0111]

[0112]

[0113]

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a refrigerant circuit diagram for describing an operation state of only cooling or heating in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a refrigerant circuit diagram for describing an operating state mainly including heating in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 4 is a refrigerant circuit diagram for illustrating an operation state mainly including cooling in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 5 is a flowchart showing control contents of a valve opening degree of the first flow control device in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 6 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 2 of the present invention.

FIG. 7 is an overall configuration diagram centered on a refrigerant system of an air-conditioning apparatus according to Embodiment 3 of the present invention.

FIG. 8 is a configuration diagram showing a control mechanism of a first flow control device in an air conditioner according to Embodiment 3 of the present invention.

FIG. 9 is a flowchart showing control contents of a valve opening degree of a first flow control device in an air conditioner according to Embodiment 3 of the present invention.

FIG. 10 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 4 of the present invention.

FIG. 11 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 5 of the present invention.

FIG. 12 is a block diagram showing a capacity control system of a compressor in an air-conditioning apparatus according to Embodiment 5 of the present invention in a cooling only operation and a cooling main operation.

FIG. 13 is a flowchart showing the content of capacity control of the compressor in the air-conditioning apparatus according to Embodiment 5 of the present invention in the cooling only operation and in the cooling main operation.

FIG. 14 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 6 of the present invention.

FIG. 15 is a block diagram showing control contents of a valve opening degree of a fifth flow control device in a cooling only operation and a cooling main operation in an air conditioner according to Embodiment 6 of the present invention.

FIG. 16 is a flowchart illustrating the control of the valve opening degree of the fifth flow control device in the air-conditioning apparatus according to Embodiment 6 of the present invention in the cooling-only operation and the cooling-main operation mode.

FIG. 17 is an overall configuration diagram centered on a refrigerant system of an air-conditioning apparatus according to Embodiment 7 of the present invention.

FIG. 18 is a block diagram showing control contents of an on-off valve of a bypass circuit in cooling only and in a cooling main operation in an air conditioner according to Embodiment 7 of the present invention.

FIG. 19 is a flowchart illustrating control of an on-off valve of a bypass circuit in an air-conditioning apparatus according to Embodiment 7 of the present invention when only cooling is performed and mainly cooling is performed.

FIG. 20 is an overall configuration diagram centering on a refrigerant system of an air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 21 is a block diagram showing control contents of a three-way switching valve in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 22 is a circuit diagram showing an example of an electrical connection in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 23 is a flowchart showing a valve opening control program for a three-way switching valve in the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 24 is an overall configuration diagram centered on a refrigerant system of an air conditioner according to Embodiment 2 of the present invention.

FIG. 25 is a block diagram illustrating control contents of a three-way switching valve and a first flow control device in the air-conditioning apparatus according to Embodiment 2 of the present invention.

FIG. 26 is a circuit diagram showing an example of an electrical connection in the air-conditioning apparatus according to Embodiment 2 of the present invention.

FIG. 27 is a flowchart illustrating a three-way switching valve and a valve opening degree control program of a first flow control device in the air-conditioning apparatus according to Embodiment 2 of the present invention.

FIG. 28 is an overall configuration diagram showing an example of a conventional air conditioner.

FIG. 29 is an overall configuration diagram showing another example of the conventional air conditioner.

[Explanation of symbols]

A heat source unit, B, C, D indoor unit, E repeater, 1 compressor, 2 4 way valve, 3 heat source unit side heat exchanger, 4 accumulator, 5 indoor side heat exchanger, 6 first connection piping, 7
Second connection pipe, 8 three-way switching valve (valve device), 9 first flow control device, 10 first branch portion, 11 second branch portion, 12 gas-liquid separation device, 13 second flow control device , 14 bypass piping, 15 third flow control device,
17 fourth flow control device, 19 first heat exchange section, 26
Second pressure detecting means (subcool amount detecting means), 27
First temperature detecting means (subcool amount detecting means), 28
Fifth flow control device, 40 flow path switching device, 50 suction air temperature detecting means, 51 opening degree setting means, 52 first
Valve opening control means, 55 control mechanism, 56 fourth valve opening control means, 57 clocking means, 58 compressor capacity control means, 59 subcooling amount detection means, 63 fifth valve opening control means, 68 bypass Circuit, 73 sixth valve opening control means, 84 first stop time counting means, 87 first
Control means, 93 second stop time counting means, 94
Second control means.

──────────────────────────────────────────────────続 き Continuation of the front page (31) Priority claim number Japanese Patent Application No. 3-10415 (32) Priority date Hei 3 (1991) January 31 (33) Priority claim country Japan (JP) (31) Priority Claim number Japanese Patent Application No. 3-10710 (32) Priority Date Heisei 3 (1991) January 31 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-10711 (32) Priority Japan Heisei 3 (1991) January 31 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-14031 (32) Priority Japan Heisei 3 (1991) February 5 (33) ) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No.3-14162 (32) Priority date Heisei 3 (1991) February 5 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-14200 (32) Priority Date Heisei 3 (1991) February 5 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-26000 (32) )priority Hei 3 (1991) February 20 (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-26001 (32) Priority date Hei 3 (1991) February 20 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-64631 (32) Priority date Hei 3 (1991) March 28 (33) Priority claiming country Japan (JP) (72) Invention Tomohiko Kasai 6-66, Teira, Wakayama-shi Mitsubishi Electric Corporation Wakayama Works (72) Inventor Shigeo Takada 6-66, Tehira Wakayama-shi Mitsubishi Electric Corporation Wakayama Works (72) Inventor Kameyama Junichi Wakayama 6-chome 5-66, Mitsubishi Electric Corporation Wakayama Works (56) References JP-A-63-96438 (JP, A) JP-A-1-167561 (JP, A) JP-A-2- 57873 (JP, A) JP-A-2-195161 (JP, A) JP-A-63-131961 (JP, A) JP-A-55-12372 (JP, A) JP-A-2-118364 (JP, A) JP-A-2-13760 (JP, A) 258971 (JP, A) (58 ) investigated the field (Int.Cl. ^6, DB name) F25B 29/00 361 F25B 13/00 104

Claims (8)

(57) [Claims] 1. A piping system comprising one heat source unit having a compressor, a four-way valve and a heat source unit side heat exchanger, and a plurality of indoor units having an indoor side heat exchanger and a first flow control device. An air-conditioning apparatus that performs cooling and heating operation by supplying a refrigerant from the heat source unit to the plurality of indoor units, wherein suction air temperature detection means for respectively detecting intake air temperatures of the plurality of indoor units; An opening setting means for setting a valve opening of the first flow control device; and a first valve opening control means for controlling the valve opening of the first flow control device to the set valve opening. A plurality of opening setting control zones corresponding to the required air conditioning capacity based on a difference between the detected temperature of the intake air temperature detecting means and a set target temperature of the indoor unit, and a minimum valve opening is set for each control zone. , The valve opening of the first flow control device is divided by a predetermined value up to the minimum valve opening. In the air conditioner being characterized in that so as to adjust the control. 2. A piping system comprising one heat source unit having a compressor, a four-way valve and a heat source unit side heat exchanger, and a plurality of indoor units having an indoor side heat exchanger and a first flow control device. In the air conditioner, which is connected and supplies a refrigerant from the heat source unit to the plurality of indoor units to perform a cooling / heating operation, when the indoor unit is stopped, the valve opening of the first flow control device is set to a predetermined opening. An air conditioner characterized by being closed after being maintained for a predetermined time. 3. A fourth valve opening control means for setting the valve opening of the first flow control device to a predetermined ratio of the valve opening just before the stop when the indoor unit is stopped; 3. The air conditioner according to claim 2, further comprising: a time measuring means for measuring a time for which the flow rate control device maintains the predetermined ratio of valve opening. 4. A pipe connecting a single heat source unit having a compressor, a four-way valve and a heat source unit side heat exchanger, and a plurality of indoor units having an indoor side heat exchanger and a first flow control device. A subcool amount detecting means for detecting the indoor unit inlet subcool amount during cooling operation by supplying a refrigerant from the heat source unit to the plurality of indoor units and performing a cooling / heating operation; and the subcool amount detecting means. Determining a capacity control target value of the compressor according to the detected subcool amount, and compressor capacity control means for controlling the capacity of the compressor based on the capacity control target value. The heat source unit and the plurality of indoor units are connected through first and second connection pipes, and one of the indoor heat exchangers of the plurality of indoor units is connected to the first heat exchanger.
A first branch portion having a valve device that is switchably connected to the connection pipe or the second connection pipe, and the other of the indoor heat exchangers of the plurality of indoor units via a first flow control device. And a second branch connected to the second connection pipe via a second flow control device; and connecting the second branch to the first connection pipe. A bypass pipe provided with a third flow control device, a downstream end of the third flow control device, and an associated portion of a second connection pipe on each indoor unit side in the second branch portion; A second heat exchange section that performs heat exchange with a bypass pipe, and a pipe that connects the four-way valve, the accumulator, and the compressor in this order, and in the middle of a pipe that connects the four-way valve and the accumulator. Low pressure saturation temperature detecting means provided, the first flow control device A second pressure detection unit disposed between the second flow control device and the third flow control device and the second heat exchange unit on an upstream side of the third flow control device; A first temperature detecting means disposed between the first and second compressors, wherein the subcool amount detecting means comprises the second pressure detecting means and the first temperature detecting means; A third flow rate control device inlet subcool amount determining means for determining an indoor unit inlet subcool amount from a difference between a saturation temperature of a pressure detected by the second pressure detecting means and a temperature detected by the first temperature detecting means; A low pressure saturation temperature target value determining means for determining a low pressure saturation temperature target value as a capacity control target value based on the indoor unit inlet subcool amount determined by the third flow rate control device inlet subcool amount determining means; Temperature target value and low Capacity control means for controlling the capacity of the compressor in accordance with the difference between the temperature detected by the pressure saturation temperature detection means and the capacity of the compressor in accordance with the indoor unit inlet subcool amount during cooling operation. An air conditioner characterized by ensuring a sufficient amount of circulating refrigerant. 5. A single heat source unit having a compressor, a four-way valve, a heat source unit side heat exchanger and an accumulator, and a plurality of indoor units having an indoor side heat exchanger and a first flow control device. In an air conditioner that performs cooling and heating operation by supplying a refrigerant from the heat source unit to the plurality of indoor units, the air conditioner is provided in a piping path that connects a lower part of the accumulator and an outlet pipe of the accumulator. A fifth flow control device, a subcool amount detecting means for detecting an indoor unit entrance subcool amount during the cooling operation, and a valve opening of the fifth flow control device according to the subcool amount detected by the subcool amount detecting device. And a fifth valve opening control means for controlling the air conditioner to supply the liquid refrigerant stored in the accumulator to the compressor in accordance with the indoor unit inlet subcooling amount during the cooling operation, thereby providing sufficient refrigerant circulation. An air conditioning apparatus is characterized in that so as to ensure. 6. A heat source unit and a plurality of indoor units are connected via first and second connection pipes, and one of the indoor heat exchangers of the plurality of indoor units is connected to the first indoor heat exchanger.
A first branch unit having a valve device that is switchably connected to the connection pipe or the second connection pipe, and the other of the indoor heat exchangers of the plurality of indoor units via a first flow control device. And a second branch portion connected to the second connection pipe via a second flow control device, wherein the subcool amount detecting means includes the first flow control device and the second flow control device. The air conditioner according to claim 5, further comprising a second pressure detecting means and a first temperature detecting means disposed between the second pressure detecting means and the second flow control device. 7. A bypass pipe which connects the second branch portion and the first connection pipe, and is provided with a third flow control device,
A second heat exchange provided downstream of the third flow control device and exchanging heat between a junction of a second connection pipe on each indoor unit side in the second branch and the bypass pipe; A first temperature detecting means disposed upstream of the third flow control device between the third flow control device and the second heat exchange unit; a fifth valve A third flow rate control device inlet subcool amount determining unit for determining an indoor unit inlet subcool amount based on a difference between a saturation temperature of the pressure detected by the second pressure detecting unit and a temperature detected by the first temperature detecting unit; A fifth flow control device reference opening determining means for determining a reference valve opening of the fifth flow control device based on the operating frequency of the compressor and the outside air temperature;
The fifth step of determining the valve opening of the fifth flow control device to be the reference valve opening or the special valve opening based on the indoor unit inlet subcool amount determined by the flow controller inlet subcool amount determining means. The air conditioner according to claim 6, further comprising a flow control device opening degree determining means. 8. A single heat source unit having a compressor, a four-way valve, a heat source unit side heat exchanger and an accumulator, and a plurality of indoor units having an indoor side heat exchanger and a first flow control device. And a refrigerant is supplied from the heat source unit to the plurality of indoor units to selectively perform a cooling / heating operation for each of the plurality of indoor units, and connects the accumulator and the four-way valve. A bypass circuit for connecting a pipe and a discharge-side high-pressure gas pipe of the compressor; a subcool amount detecting means for detecting an indoor unit inlet subcool amount during a cooling operation; and an indoor unit inlet subcool amount detected by the subcool amount detecting means. An air conditioner provided with sixth valve opening control means for controlling the valve opening of the bypass circuit in accordance with the condition (1), wherein the heat source unit and the plurality of indoor units are connected via the first and second connection pipes. Connect with the plurality The indoor side while the first heat exchanger of the indoor unit
A first branch unit having a valve device that is switchably connected to the connection pipe or the second connection pipe; and the first branch unit to the other of the indoor heat exchangers of the plurality of indoor units.
And a second connection pipe connected to the second connection pipe via a second flow control device.
A bypass pipe connecting the second branch section and the first connection pipe, a bypass pipe provided with a third flow control device, and a bypass pipe provided downstream of the third flow control apparatus; A second heat exchange section that performs heat exchange between the junction section of the second connection pipe on each indoor unit side in the second branch section and the bypass pipe; the first flow control device and the second A second pressure detecting means disposed between the third flow control device and the second heat exchange unit on an upstream side of the third flow control device. A first temperature detecting means disposed in the sub-cooling amount detecting means, wherein the subcool amount detecting means comprises the second pressure detecting means and the first temperature detecting means, and the sixth valve opening degree control Means for detecting the saturation temperature of the pressure detected by the second pressure detection means and the temperature detected by the first temperature detection means; Third determining the indoor unit inlet subcool amount from the difference
An air conditioner comprising: a flow control device inlet subcool amount determining means; and a bypass circuit valve opening / closing control means for controlling a valve opening of the bypass circuit based on the indoor unit inlet subcool amount. .