JPH055576A - Air conditioner - Google Patents

Abstract

PURPOSE:To prevent damage of a compressor by providing control means for increasing a valve opening of a special flow controller by a predetermined amount if a discharge temperature detected by discharge temperature detecting means provided between the compressor and a four-way switching valve is higher than a preset predetermined temperature. CONSTITUTION:If a discharge temperature detected by discharge temperature detecting means 42 exceeds a preset predetermined temperature during an operation of a compressor 1, a valve opening of a third flow controller 15 of third and fourth flow controllers 15 and 17, is preferentially increased. In this manner, a pressure loss is reduced to allow refrigerant to easily flow. Thus, quantity of refrigerant to be returned to a heat source A is increased, a specific volume of refrigerant to be sucked to the compressor 1 is reduced, and rise of the discharge temperature can be suppressed. That is, a decrease in lubricity of refrigerator oil due to excessive rise of the discharge temperature and hence damage of the compressor 1 are prevented.

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 air conditioner in which a plurality of indoor units are connected to one heat source unit, and in particular, heating and cooling are selectively applied to each indoor unit, and The present invention relates to an air conditioner capable of simultaneously performing cooling in one indoor unit and heating in the other indoor unit.

[0002]

2. Description of the Related Art The prior art of the present invention will be described below. FIG. 4 is an overall configuration diagram centering on the refrigerant system of the conventional air conditioner of the present invention. 5 to 7 show operating states during cooling / heating operation in the air conditioner shown in FIG. 4, FIG. 5 is an operating state diagram of only cooling or heating, and FIGS. 6 and 7 show simultaneous cooling / heating operation. FIG. 6 is an operation state diagram showing a heating operation (when the heating operation capacity is larger than the cooling operation capacity), and FIG. 7 is an operation operation state diagram showing the cooling operation (when the cooling operation capacity is larger than the heating operation capacity). .. In this prior art, one heat source unit and one indoor unit 3
The case where two units are connected will be described, but the same applies when two or more indoor units are connected.

In FIG. 4, A is a heat source unit, and B, C, and D are indoor units connected in parallel with each other, which will be described later, and have the same structure. As will be described later, E is a first branch part 10, a second flow rate control device 13, a second branch part 11, a gas-liquid separation device 12, heat exchange parts 16a, 16b, 16c, 16d, 19,
It is a repeater having a third flow control device 15 and a fourth flow control device 17 incorporated therein. Further, 1 is a compressor, 2 is a four-way switching valve for switching the refrigerant flow direction of the heat source unit, 3 is a heat source unit side heat exchanger, 4 is an accumulator, and is connected to the compressor 1 via the four-way switching valve 2. There is. The heat source machine A is constituted by these. Further, 5 is an indoor heat exchanger provided in the three indoor units B, C, D, 6 is a four-way switching valve 2 of the heat source unit A and a relay unit E via a fourth check valve 33 described later. The thick first connecting pipes 6b, 6c, and 6d are connected to the indoor unit B, respectively.
The indoor heat exchangers 5 of C and D are connected to the repeater E, and the indoor unit-side first connecting pipes corresponding to the first connecting pipes 6 and 7 are the heat source unit side heat exchangers 3 of the heat source unit A. Is a second connecting pipe that is thinner than the first connecting pipe for connecting the relay device E via a third check valve 32 described later.

Further, 7b, 7c and 7d are indoor units B and
The indoor heat exchanger 5 of C and D is connected to the relay E via the first flow rate control device 9, and is a second connection pipe on the indoor unit side corresponding to the second connection pipe 7. Reference numeral 8 is a three-way switching valve that connects the first connection pipes 6b, 6c, 6d on the indoor unit side to the first connection pipe 6 or the second connection pipe 7 side in a switchable manner. Reference numeral 9 is a first flow rate control device which is connected close to the indoor heat exchanger 5 and is controlled by the superheat amount on the outlet side of the indoor heat exchanger 5 during cooling and by the subcool amount during heating. It is connected to the second connection pipes 7b, 7c, 7d on the machine side. Reference numeral 10 designates the first connecting pipes 6b, 6c, 6d on the indoor unit side as the first
It is a first branch portion including a three-way switching valve 8 switchably connected to the connection pipe 6 or the second connection pipe 7. 11
Is a second branch portion including the second connection pipes 7b, 7c, 7d on the indoor unit side and the second connection pipe 7. Reference numeral 12 is a gas-liquid separator provided in the middle of the second connecting pipe 7, the gas phase part of which is connected to the first port 8a of the three-way switching valve 8 and the liquid phase part of which is the second part.
Is connected to the branch part 11. Reference numeral 13 denotes a second flow rate control device (here, an electric expansion valve) that is openable and closable and is connected between the gas-liquid separation device 12 and the second branch portion 11.

Reference numeral 14 is a bypass pipe connecting the second branch portion 11 and the first connection pipe 6, and 15 is a third flow rate control device (here, an electric expansion valve) provided in the middle of the bypass pipe 14. , 16a are provided downstream of the third flow rate control device 15 provided in the middle of the bypass pipe 14, and the connecting portion of the second connection pipes 7b, 7c, 7d on the side of each indoor unit in the second branch portion 11 Is a second heat exchanging portion for exchanging heat with the heat exchanger. 16
b, 16c, 16d are respectively provided downstream of the third flow rate control device 15 provided in the middle of the bypass pipe 14, and the second connection pipes 7b, 7c on the indoor unit side in the second branch section 11 are provided.
It is a third heat exchanging section for exchanging heat with the 7d. 19 is provided in the bypass pipe 14 downstream of the third flow rate control device 15 and downstream of the second heat exchange section 16a, and connects the gas-liquid separation device 12 and the second flow rate control device 13 to each other. A first heat exchange section for performing heat exchange between the two, and a second branch section 17
It is a fourth flow rate control device (here, an electric expansion valve) that is openable and closable and is connected between 11 and the first connection pipe 6.

On the other hand, reference numeral 32 is a third check valve provided between the heat source unit side heat exchanger 3 and the second connection pipe 7, from the heat source unit side heat exchanger 3 to the first check valve. 2 connection pipe 7
Allows refrigerant flow only to. 33 is a fourth provided between the four-way switching valve 2 of the heat source unit A and the first connecting pipe 6.
Is a check valve for permitting refrigerant flow only from the first connecting pipe 6 to the four-way switching valve 2. Reference numeral 34 is a fifth check valve provided between the heat source unit A four-way switching valve 2 and the second connection pipe 7, and the refrigerant is only from the four-way switching valve 2 to the second connection pipe 7. Allow distribution. Reference numeral 35 is a sixth check valve provided between the heat source unit side heat exchanger 3 and the first connection pipe 6, and the heat source unit side heat exchanger 3 is connected from the first connection pipe 6. Allows refrigerant flow only to. The third, fourth, fifth, and sixth check valves 32, 33, 34, 35 are switching valves.
Make up 40.

Reference numeral 25 is a first pressure detecting means provided between the first branch portion 10 and the second flow control device 13, and 26 is the second flow control device 13 and the fourth flow control device. A second pressure detecting means provided between the device 17 and the device 17 is a third pressure detecting means provided in the first connecting pipe 6 part. Further, 41 is a low pressure saturation temperature detecting means provided in the middle of a pipe connecting the four-way switching valve 2 and the accumulator 4.
42 is a discharge temperature detecting means provided in the middle of the pipe connecting the four-way switching valve 2 and the accumulator 4, and 18 is a fourth provided in the middle of the pipe connecting the compressor 1 and the four-way switching valve 2. Is a pressure detecting means.

Next, the operation will be described. First, the case of only the cooling operation will be described with reference to FIG. The high-temperature high-pressure refrigerant gas discharged from the compressor 1 whose capacity is controlled so that the temperature detected by the low-pressure saturation temperature detecting means 41 reaches a predetermined value as shown by the solid line arrow in the figure passes through the four-way switching valve 2 and the heat source unit. After the heat is exchanged with the air in the side heat exchanger 3 to be condensed, the third check valve 32, the second connection pipe 7, the gas-liquid separation device 12, and the second flow rate control device 13 are passed in this order, and further. Each of the indoor units B, passing through the second branch portion 11 and the second connection pipes 7b, 7c, 7d on the indoor unit side,
It flows into C and D. The refrigerant flowing into each indoor unit B, C, D is decompressed to a low pressure by the first flow rate control device 9 controlled by the superheat amount at the outlet of each indoor heat exchanger 5, and the indoor heat exchanger 5 is cooled. It heats and exchanges heat with the room air, is gasified, and cools the room.

The refrigerant in the gas state is the first connection pipes 6b, 6c, 6d on the indoor unit side, the three-way switching valve 8, the first branch portion 10, the first connection pipe 6, and the reverse pipe of the fourth connection pipe. A circulation cycle in which the compressor 1 is sucked through the stop valve 33, the four-way switching valve 2 of the heat source unit A, and the accumulator 4 constitutes 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 are closed.
8c is open circuit. At this time, the refrigerant inevitably circulates to the third check valve 32 and the fourth check valve 33 because the first connecting pipe 6 has a low pressure and the second connecting pipe 7 has a high pressure. In addition, during this cycle, a part of the refrigerant that has passed through the second flow rate control device 13 enters the bypass pipe 14 and is depressurized to a low pressure by the third flow rate control device 15, so that the third heat exchange parts 16b, 16c, At 16d, the second connecting pipes 7b, 7c on the indoor unit side of the second branch portion 11 are provided.
7d and the second branch part 11 in the second heat exchange part 16a.
Between the second connection pipes 7b, 7c, 7d on the side of each indoor unit, and with the refrigerant flowing into the second flow rate control device 13 at the first heat exchange unit 19. The refrigerant that has been exchanged and evaporated is
It enters the first connecting pipe 6 and the fourth check valve 33, and is sucked into the compressor 1 via the four-way switching valve 2 of the heat source unit A and the accumulator 4.

On the other hand, the first, second and third heat exchange parts 19, 16
The refrigerant in the second branch portion 11 that has been subjected to heat exchange and cooling in a, 16b, 16c, 16d and is sufficiently subcooled flows into the indoor units B, C, D that are about to be cooled.

Next, the case of only the heating operation will be described with reference to FIG. That is, as shown by the dotted arrow in the figure, the high-temperature high-pressure refrigerant gas discharged from the compressor 1 whose capacity is controlled so that the pressure detected by the fourth pressure detecting means 18 becomes a predetermined value is the four-way switching valve 2 Through the fifth check valve 34, the second
Through the connecting pipe 7 and the gas-liquid separation device 12 of the first branch 1
0, three-way switching valve 8, first connection pipes 6b, 6c, 6 on the indoor unit side
The air flows into each of the indoor units B, C, and D in the order of d, exchanges heat with the indoor air to be condensed and liquefied, and heats the room.

The refrigerant in this liquid state is controlled by the subcool amount at the outlet of each indoor heat exchanger 5 and passes through the first flow rate control device 9 in a substantially fully opened state, and then the second connection on the indoor unit side. From the pipes 7b, 7c, 7d, they flow into the second branch portion 11 and merge, and further pass through the fourth flow control device 17. Here, the first flow control device 9 or the third and fourth flow control devices 15, 17
The pressure is reduced to a low pressure gas-liquid two-phase state. The refrigerant depressurized to a low pressure flows into the sixth check valve 35 of the heat source unit A and the heat source unit side heat exchanger 3 through the first connection pipe 6, exchanges heat with the air and becomes a gas state. , The four-way switching valve 2 of the heat source unit A,
A circulation cycle in which the compressor 1 is sucked through the accumulator 4 constitutes a heating operation. At this time, the three-way switching valve 8
The second port 8b is closed, and the first port 8a and the third port 8c are open. At this time, the refrigerant is inevitably the fifth check valve 34, because the first connecting pipe 6 has a low pressure and the second connecting pipe 7 has a high pressure.
It flows to the sixth check valve 35.

Next, the case of mainly heating in the simultaneous cooling and heating operation will be described with reference to FIG. The high-temperature high-pressure refrigerant gas discharged from the compressor 1 whose capacity is controlled so that the pressure detected by the fourth pressure detecting means 18 reaches a predetermined value as shown by the dotted arrow in the figure passes through the four-way switching valve 2 to 5 check valve 34, second
Sent to the repeater E through the connection pipe 7 of the
After passing through 12, the first branch portion 10, the three-way switching valve 8, and the first connection pipes 6b and 6c on the indoor unit side in this order, flow into the indoor units B and C that are going to be heated, and heat exchange on the indoor side. In the vessel 5, heat is exchanged with room air to be condensed and liquefied, and the room is heated. The condensed and liquefied refrigerant passes through the first flow rate control device 9 which is controlled by the subcool amount at the outlet of each indoor heat exchanger 5 and is in a substantially fully opened state, and is slightly depressurized and flows into the second branch portion 11. ..

A 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 controlled by the superheat amount at the outlet of the indoor heat exchanger 5. After entering the flow rate control device 9 of No. 1 and being decompressed, it enters the indoor heat exchanger 5 to exchange heat and evaporate into a gas state to cool the room, and the three-way switching valve via the first connecting pipe 6d. 8
Through the first connecting pipe 6. On the other hand, the other refrigerant passes through the fourth flow rate control device 17 which is controlled so that the pressure difference between the pressure detected by the first pressure detecting means 25 and the pressure detected by the second pressure detecting means 26 falls within a predetermined range. , The first connecting pipe 6 which is thick to join with the refrigerant having passed through the indoor unit D to be cooled
After that, the gas flows into the sixth check valve 35 of the heat source unit A and the heat source unit side heat exchanger 3 to exchange heat with the air and evaporate into a gas state.

This refrigerant constitutes a circulation cycle in which it is drawn into the compressor 1 via the four-way switching valve 2 of the heat source unit A and the accumulator 4, and performs heating-main operation. At this time, the evaporation pressure of the indoor side heat exchanger 5 of the indoor unit D to be cooled and the pressure difference of the heat source unit side heat exchanger 3 are reduced due to 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 8a are closed.
8c is open, the first port 8a of the indoor unit D is closed, the second port
8b and the third mouth 8c are opened. At this time, the refrigerant is
Since the first connecting pipe 6 has a low pressure and the second connecting pipe 7 has a high pressure, the first connecting pipe 6 necessarily flows to the fifth check valve 34 and the sixth check valve 35.

During this cycle, a part of the liquid refrigerant enters the bypass pipe 14 from the connecting portion of the second connecting pipes 7b, 7c, 7d on the indoor unit side of the second branching portion 11 and controls the third flow rate. The pressure is reduced to a low pressure by the device 15, and the third heat exchange parts 16b, 16c, 16d
The second connection pipes 7b, 7 on the indoor unit side of the second branching unit 11
c, 7d, and between the second heat exchanging portion 16a and the second connecting pipes 7b, 7c, 7d on the side of each indoor unit of the second branching portion 11, the first connecting portion is further connected. The second flow rate control device in the heat exchange section 19 of
The heat exchange is performed with the refrigerant flowing in from 13, and the evaporated refrigerant enters the heat source unit side heat exchanger 3 via the first connecting pipe 6 and the sixth check valve 35, and the After exchanging and evaporating, it is sucked into the compressor 1 through the four-way switching valve 2 of the heat source unit A and the accumulator 4. On the other hand, the second branch portion 11 is heat-exchanged by the first, second, and third heat exchange portions 19, 16a, 16b, 16c, 16d, cooled, and sufficiently subcooled.
Of the refrigerant flows into the indoor unit D that is about to be cooled.

Next, a case of mainly cooling in the simultaneous heating and cooling operation will be described with reference to FIG. As indicated by the solid line arrow in the figure, the high-temperature high-pressure refrigerant gas discharged from the compressor 1 whose capacity is controlled so that the temperature detected by the low-pressure saturation temperature detecting means 41 reaches a predetermined value passes through the four-way switching valve 2 and becomes a heat source. It flows into the machine-side heat exchanger 3 and exchanges heat with air to be in a gas-liquid two-phase high-temperature high-pressure state. Then, the two-phase high-temperature high-pressure refrigerant is sent to the gas-liquid separation device 12 of the relay machine E through 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 the first branch portion.
10, the three-way switching valve 8, the first connection pipe 6d on the indoor unit side, in that order, flows into the indoor unit D to be heated, heat-exchanges with the indoor air in the indoor heat exchanger 5, and is condensed and liquefied. Heat the room. Further, it is controlled by the amount of subcool at the outlet of the indoor heat exchanger 5, passes through the first flow rate control device 9 in a substantially fully opened state, is slightly decompressed, and flows into the second branch portion 11.

On the other hand, the remaining liquid refrigerant passes through the second flow rate control device 13 controlled by the pressure detected by the first pressure detecting means 25 and the pressure detected by the second pressure detecting means 26, and then the second branch. It flows into the portion 11 and joins the refrigerant passing through the indoor unit D to be heated. The second branch portion 11 and the second connection pipes 7b and 7c on the indoor unit side are passed in this order to flow into the indoor units B and C.
The refrigerant flowing into each of the indoor units B and C is used as the indoor unit side heat exchanger 5
After being depressurized to a low pressure by the first flow rate control device 9 controlled to the superheat amount at the outlet of, the gas flows into the indoor heat exchanger 5, exchanges heat with the indoor air, is evaporated, and is gasified,
Cool the room. Furthermore, the refrigerant in this gas state is
Indoor unit side first connection piping 6b, 6c, three-way switching valve 8, first
Passing through the branch portion 10 of the first connecting pipe 6 and the fourth check valve 3
3. A circulation cycle in which the compressor 1 is sucked through the four-way switching valve 2 of the heat source device A and the accumulator 4 is configured to perform the cooling main operation. At this time, the first port 8a of the three-way switching valve 8 connected to the indoor units B and C is closed, the second port 8b and the third port 8c are open, and the second port 8b of the indoor unit D is Cycle, 1st mouth 8a
And the third mouth 8c is opened. At this time, the refrigerant inevitably circulates to the third check valve 32 and the fourth check valve 33 because the first connecting pipe 6 has a low pressure and the second connecting pipe 7 has a high pressure.

During this cycle, a part of the liquid refrigerant enters the bypass pipe 14 from the meeting portion of the second connecting pipes 7b, 7c, 7d on the side of each indoor unit of the second branch portion 11 and reaches the third flow rate. Controller 15
Depressurized to low pressure by the third heat exchange parts 16b, 16c, 16
The second connection pipe 7b on the indoor unit side of the second branch portion 11 at d,
7c and 7d, and between the second heat exchanger section 16a and the second connecting pipes 7b, 7c, 7d on the side of each indoor unit of the second branch section 11 and the meeting section of the second connecting section 7a. In the first heat exchange section 19, heat is exchanged with the refrigerant flowing into the second flow rate control device 13, and the evaporated refrigerant enters the first connecting pipe 6 and the fourth check valve 33, and the heat source unit A
It is sucked into the compressor 1 through the four-way switching valve 2 and the accumulator 4. On the other hand, the first, second and third heat exchange parts 19, 16
The refrigerant in the second branch portion 11 that has been heat-exchanged and cooled by a, 16b, 16c, and 16d and is sufficiently subcooled flows into the indoor units B and C that are about to be cooled.

[0020]

Since the conventional multi-chamber heat pump type air conditioner is constructed as described above, if the compressor discharge temperature rises excessively during operation, the lubricity of the refrigerating machine oil will deteriorate. However, there was a problem that the compressor was damaged. As an approximation technique, there is JP-A-1-134172.

The present invention has been made to solve the above problems, and a plurality of indoor units are connected to one heat source unit, and heating / cooling is selectively performed for each indoor unit. In an air conditioner that can perform cooling in one indoor unit and heating in the other indoor unit at the same time, if the discharge temperature of the compressor rises excessively, the lubricity of the refrigerating machine oil decreases and the compressor is damaged. The purpose is to prevent.

[0022]

SUMMARY OF THE INVENTION An air conditioner according to the present invention comprises a heat source unit comprising a compressor, a four-way switching valve, a heat source unit side heat exchanger, an accumulator, etc., and an indoor side heat exchanger, In a case where a plurality of indoor units including a first flow rate control device and the like are connected via first and second connection pipes, one of the indoor heat exchangers of the plurality of indoor units is The first branch part that is switchably connected to the first connection pipe or the second connection pipe, and the other of the indoor heat exchangers of the plurality of indoor units are connected to the first flow control device. A second flow rate control device is interposed between the second flow path control device and the second branch portion connected to the second connection pipe via the second flow path, and the second branch portion and the first connection pipe are connected to the fourth flow rate. The second flow path is connected to the second branch portion, and the other end is connected to the third flow path. A bypass pipe connected to the first connection pipe via a control device; a bypass pipe between the third flow rate control device and the first connection pipe; the second connection pipe; A first heat exchanging section for exchanging heat with a pipe connecting the second flow rate control device is provided, and the first branch section, the second branch section, the second flow rate control apparatus, and the third Flow control device, fourth flow control device, first
The heat exchanger and the repeater with built-in bypass piping
It is interposed between the heat source unit and the plurality of indoor units, and the first connecting pipe has a larger diameter than the second connecting pipe, and the heat source unit side heat exchanger is a condenser. During the operation, the refrigerant is circulated only from the refrigerant outlet side of the condenser to the second connection pipe side, and the refrigerant is circulated only from the first connection pipe to the four-way switching valve side, and the heat source unit side. During operation in which the heat exchanger serves as an evaporator, the refrigerant is circulated from the first connection pipe only to the refrigerant inflow side of the evaporator, and the refrigerant is circulated only from the four-way switching valve to the second connection pipe side. If the discharge temperature detected by the discharge temperature detecting means provided between the compressor and the four-way switching valve is higher than a predetermined temperature set in advance, the third and third flow path switching devices are provided. Increase the valve opening of the flow control device of 4 by a predetermined amount It is provided with a control means that.

[0023]

According to the present invention, when the compressor discharge temperature rises, the discharge temperature detected by the discharge temperature detecting means provided between the compressor and the four-way switching valve is higher than the preset predetermined temperature. When the temperature is high, the control means for increasing the valve openings of the third and fourth flow rate control devices by a predetermined amount is provided, so that the discharge temperature rises, the lubricity of the refrigerating machine oil decreases, and the compressor is damaged. Can be prevented.

[0024]

【Example】

Example 1. Examples of the present invention will be described below.
FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air conditioner according to an embodiment of the present invention. In FIG. 1, A is a heat source unit, and B, C, and D are indoor units connected in parallel with each other as described later, and have the same configuration. As will be described later, E is a first branch part 10, a second flow rate control device 13, a second branch part 11, a gas-liquid separation device 12, heat exchange parts 16a, 16b,
16c, 16d, 19, a third flow control device 15, and a fourth flow control device 17 are built-in repeaters. 1 is a compressor,
2 is a four-way switching valve that switches the refrigerant flow direction of the heat source unit, 3
Is a heat source unit side heat exchanger, and 4 is an accumulator, which is connected to the compressor 1 via the four-way switching valve 2. The heat source machine A is constituted by these. Further, 5 is an indoor heat exchanger provided in the three indoor units B, C and D, and 6 is a heat source device A.
Thick connecting pipes for connecting the four-way switching valve 2 and the relay unit E via a fourth check valve 33 described later, 6b, 6c and 6d are indoor heat exchanges of the indoor units B, C and D, respectively. The first connection pipe on the indoor unit side that connects the unit 5 and the relay unit E and corresponds to the first connection pipe 6 is a heat source unit side heat exchanger 3 of the heat source unit A and the relay unit E which will be described later. The above-mentioned first connecting through check valve 32 of No. 3
2 is a second connection pipe thinner than the connection pipe of FIG.

Further, 7b, 7c and 7d are indoor units B and 7b, respectively.
The indoor heat exchanger 5 of C and D is connected to the relay E via the first flow rate control device 9, and is a second connection pipe on the indoor unit side corresponding to the second connection pipe 7. Reference numeral 8 is a three-way switching valve that connects the first connection pipes 6b, 6c, 6d on the indoor unit side to the first connection pipe 6 or the second connection pipe 7 side in a switchable manner. Reference numeral 9 is a first flow rate control device which is connected close to the indoor heat exchanger 5 and is controlled by the superheat amount on the outlet side of the indoor heat exchanger 5 during cooling and by the subcool amount during heating. Side second connection pipes 7b, 7c, 7d. Reference numeral 10 is a first branch portion including a three-way switching valve 8 that connects the first connection pipes 6b, 6c, 6d on the indoor unit side to the first connection pipe 6 or the second connection pipe 7 in a switchable manner. .. 11
Is a second branch portion composed of the second connection pipes 7b, 7c, 7d and the second connection pipe 7 on the indoor unit side. Reference numeral 12 is a gas-liquid separator provided in the middle of the second connecting pipe 7, the gas phase portion of which is connected to the first port 8a of the three-way switching valve 8, and the liquid phase portion of which is connected to the second branch portion 11. It is connected. 13 is the gas-liquid separation device 12 and the second
Is a second flow control device (here, an electric expansion valve) that can be opened and closed and that is connected to the branch portion 11 of the.

Reference numeral 14 is a bypass pipe connecting the second branch portion 11 and the first connection pipe 6, and 15 is a third flow control device (here, an electric expansion valve) provided in the middle of the bypass pipe 14. , 16a are provided downstream of the third flow rate control device 15 provided in the middle of the bypass pipe 14, and the connecting portion of the second connection pipes 7b, 7c, 7d on the side of each indoor unit in the second branch portion 11 Is a second heat exchanging portion for exchanging heat with the heat exchanger. 16
b, 16c, 16d are respectively provided downstream of the third flow rate control device 15 provided in the middle of the bypass pipe 14, and the second connection pipes 7b, 7c on the indoor unit side in the second branch section 11 are provided.
It is a third heat exchanging section for exchanging heat with the 7d. 19 is provided in the bypass pipe 14 downstream of the third flow rate control device 15 and downstream of the second heat exchange section 16a, and connects the gas-liquid separation device 12 and the second flow rate control device 13 to each other. A first heat exchange section for performing heat exchange between the two, and a second branch section 17
It is a fourth flow rate control device (here, an electric expansion valve) that is openable and closable and is connected between 11 and the first connection pipe 6.

On the other hand, reference numeral 32 is a third check valve provided between the heat source side heat exchanger 3 and the second connecting pipe 7, and the heat source side heat exchanger 3 to the third check valve are provided. 2 connection pipe 7
Allows refrigerant flow only to. 33 is a fourth provided between the four-way switching valve 2 of the heat source unit A and the first connecting pipe 6.
Is a check valve for permitting refrigerant flow only from the first connecting pipe 6 to the four-way switching valve 2. Reference numeral 34 is a fifth check valve provided between the four-way switching valve 2 of the heat source unit A and the second connecting pipe 7, and the four-way switching valve 2 to the second check valve
Refrigerant is allowed to flow only to the connecting pipe 7. Reference numeral 35 is a sixth check valve provided between the heat source unit side heat exchanger 3 and the first connection pipe 6, and the heat source unit side heat exchanger 3 is connected from the first connection pipe 6. Allows refrigerant flow only to. The above-mentioned third, fourth, fifth, and sixth check valves 32, 33, 34, 35 constitute a flow path switching device 40.

Reference numeral 25 is a first pressure detecting means provided between the first branch portion 10 and the second flow rate control device 13, and 26 is the second flow rate control device 13 and the fourth flow rate control device. A second pressure detecting means provided between the device 17 and 27 is a third pressure detecting means provided in the first connecting pipe 6. Also,
Reference numeral 41 is a low pressure saturation temperature detecting means provided in the middle of the pipe connecting the four-way switching valve 2 and the accumulator 4, and 42 is a discharge provided in the middle of the pipe connecting the four-way switching valve 2 and the compressor 1. A temperature detecting means, 18 is a fourth provided in the middle of a pipe connecting the compressor 1 and the four-way switching valve 2.
Is a pressure detecting means.

Next, the operation will be described. The operations of the cooling operation only, the heating operation only, the warm main operation and the cool main operation are exactly the same as those of the conventional air conditioner shown in FIGS. 2 to 4. Therefore, the description thereof is omitted here, and the flow rate control of the third and fourth flow rate control devices 15 and 17 when the compressor discharge temperature rises will be described. During the operation of the compressor, if the discharge temperature detected by the discharge temperature detecting means 42 exceeds a preset predetermined temperature,
By increasing the valve opening degree of the third or fourth flow rate control device 15 or 17 preferentially by the predetermined valve opening degree of the third flow rate control device 15, the pressure loss is reduced and the refrigerant easily flows. Therefore, the amount of refrigerant returning to the heat source unit A increases, the specific volume of the refrigerant sucked into the compressor decreases, and the rise in discharge temperature can be suppressed.

Next, according to the flow chart of FIG. 2, the third and fourth flow rate control devices 15 and 17 at the time when the compressor discharge temperature rises.
The control content of will be described. In step 50, it is judged whether the discharge temperature detected by the discharge temperature detecting means 42 is higher or higher than a predetermined temperature set in advance. If it is higher, the process proceeds to step 51, and if it is not higher, the process proceeds to step 52. Go to. In step 52, the valve opening degree of the third flow control device 15 is not changed and the process proceeds to step 53. In step 53, the valve opening degree of the fourth flow rate control device 17 is not changed and the process returns to step 50. In step 51, it is determined whether the valve opening degree of the third flow rate control device 15 is a predetermined maximum opening degree or not, and if it is the predetermined maximum opening degree, the process proceeds to step 54 and it is not the predetermined maximum opening degree. If so, proceed to step 55. In step 55, the third
The valve opening of the flow control device 15 is increased and the process returns to step 50. In step 54, the valve opening degree of the fourth flow control device 17 is increased, and the process returns to step 50. In this way, the flow rate control of the third and fourth flow rate control devices 15 and 17 when the compressor discharge temperature rises is performed.

Example 2. In the first embodiment, the three-way switching valve 8 is provided and the first connection pipes 6b, 6c, 6d on the indoor unit side are provided.
Is connected to the first connecting pipe 6 or the second connecting pipe 7 in a switchable manner. As shown in FIG. 7, two solenoid valves 30, 31, etc. are provided on-off valves as described above. Similar effects can be obtained even if the connection is switchable.

[0032]

As described above, the air conditioner according to the present invention includes a compressor, a four-way switching valve, a heat source side heat exchanger,
In one in which one heat source device composed of an accumulator and the like and a plurality of indoor units composed of an indoor heat exchanger, a first flow rate control device, etc. are connected via first and second connection pipes A first branching portion that connects one of the indoor heat exchangers of the plurality of indoor units to the first connection pipe or the second connection pipe in a switchable manner, and the plurality of indoor units While interposing a second flow rate control device between the other of the indoor heat exchangers and a second branch portion formed by connecting the second flow path control device to the second connection pipe. ,
The second branch portion and the first connection pipe are connected via a fourth flow rate control device, one end is further connected to the second branch portion, and the other end is connected via a third flow rate control device. A bypass pipe connected to the first connection pipe; a bypass pipe between the third flow control device and the first connection pipe; the second connection pipe; and the second flow control. A first heat exchanging section for exchanging heat with a pipe connecting the apparatus is provided, and the first branching section, the second branching section, the second flow rate control device, the third flow rate control apparatus, and the third flow rate control apparatus. 4 flow control device, first
The heat exchanger and the repeater with built-in bypass piping
It is interposed between the heat source unit and the plurality of indoor units, and the first connecting pipe has a larger diameter than the second connecting pipe, and the heat source unit side heat exchanger is a condenser. During the operation, the refrigerant is circulated only from the refrigerant outlet side of the condenser to the second connection pipe side, and the refrigerant is circulated only from the first connection pipe to the four-way switching valve side, and the heat source unit side. During operation in which the heat exchanger serves as an evaporator, the refrigerant is circulated from the first connection pipe only to the refrigerant inflow side of the evaporator, and the refrigerant is circulated only from the four-way switching valve to the second connection pipe side. When a compressor discharge temperature rises by providing a flow path switching device to obtain a discharge temperature, the discharge temperature detected by the discharge temperature detecting means provided between the compressor and the four-way switching valve is higher than a predetermined temperature set in advance. If higher, the third
By providing the control means for increasing the valve opening of the fourth flow rate control device by a predetermined amount, it is possible to prevent the lubricity of the refrigerating machine oil from being lowered and the compressor from being damaged due to an excessive rise in the discharge temperature. Further, it is possible to prevent the compressor from being damaged due to the winding temperature of the compressor driving motor rising excessively due to the discharge temperature rising.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the control device for the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 3 is an overall configuration diagram centering on a refrigerant system of an air conditioner according to a second embodiment of the present invention.

FIG. 4 is an overall configuration diagram centering on a refrigerant system of a conventional air conditioner.

FIG. 5 is a refrigerant circuit diagram for explaining an operating state of only a cooling or a heating of the conventional air conditioner.

FIG. 6 is a refrigerant circuit diagram for explaining an operating state of a heating-based main body of a conventional air conditioner.

FIG. 7 is a refrigerant circuit diagram for explaining an operating state of a conventional air conditioner mainly for cooling.

[Explanation of symbols]

 1 Compressor 2 Four-way switching valve 3 Heat source side heat exchanger 4 Accumulator 5 Indoor side heat exchanger 6, 6b, 6c, 6d 1st connection pipe 7, 7b, 7c, 7d 2nd connection pipe 9 1st Flow control device 10 First branch part 11 Second branch part 13 Second flow control device 14 Bypass piping 15 Third flow control device 16a, 16b, 16c, 16d, 19 Heat exchange part 17 Fourth flow control device Device 19 First heat exchange unit 40 Flow path switching device 42 Discharge temperature detection means A Heat source unit B, C, D Indoor unit E Repeater

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Noriaki Hayashida 6-566 Tehira, Wakayama City Wakayama Works, Mitsubishi Electric Corporation (72) Tomohiko Kasai 6-566 Tehira, Wakayama Mitsubishi (72) Inventor Shigeo Takada 6-5-66, Tehira, Wakayama City Mitsubishi Electric Co., Ltd. Wakayama Factory

Claims (1)

Claim: What is claimed is: 1. A heat source unit comprising a compressor, a four-way switching valve, a heat source unit side heat exchanger, an accumulator, etc., an indoor side heat exchanger, a first flow control device, etc. In which 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 connection pipe, or The first branch part that is switchably connected to the second connection pipe and the other of the indoor heat exchangers of the plurality of indoor units are connected to the second connection part via the first flow rate control device. The second that is connected to the pipe
The second flow rate control device is interposed between the second flow rate control device and the second flow path control device, and the second flow path control device is connected to the second flow path control device via the fourth flow rate control device. The first end is connected to the branch part, and the other end is connected via the third flow rate control device.
The bypass pipe connected to the connection pipe of
Heat exchange for exchanging heat between the bypass pipe between the flow control device and the first connection pipe, and the pipe connecting the second connection pipe and the second flow control device. And includes the first branching section, the second branching section, the second flow rate control device, the third flow rate control apparatus, the fourth flow rate control apparatus, the first heat exchange section, and the bypass pipe. The relay device is interposed between the heat source unit and the plurality of indoor units, and the first connecting pipe has a diameter larger than that of the second connecting pipe. During the operation in which the exchanger serves as a condenser, the refrigerant is circulated only from the refrigerant outlet side of the condenser to the second connection pipe side, and the refrigerant is circulated from the first connection pipe only to the four-way switching valve side. And, in the operation in which the heat source side heat exchanger becomes an evaporator,
The compressor is provided with a flow path switching device that allows the refrigerant to flow from the first connection pipe only to the refrigerant inflow side of the evaporator and allows the refrigerant to flow only from the four-way switching valve to the second connection pipe side. And the four-way switching valve, the discharge temperature detected by the discharge temperature detecting means is higher than a predetermined temperature set in advance, the valve opening degree of the third and fourth flow rate control devices is determined. An air conditioner capable of simultaneous cooling and heating operation, which is provided with control means for increasing the amount by a fixed amount.