JPH1114177A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an operating pressure of an outdoor heat exchanger from being abnormally increased in an air conditioner for multi-rooms, even in the case that only a certain indoor device is operated. SOLUTION: This air conditioner is constructed such that an outdoor device 14' having a compressor 1, a four-way valve 2, an accumulator 18, an outdoor side heat exchanger 3 and an outdoor side expansion valve 5 is connected to a plurality of indoor devices 9a to 9d. In this case, the outdoor device 14' is provided with an opening or closing valve 6 arranged at an upstream side of an outdoor side expansion valve 5 during a heating operation, an opening or closing valve 12 to be opened or closed and for adjusting a flow rate in a bypassing circuit so as to connect the upstream side of the opening or closing valve 6 during heating operation with an inlet side of the accumulator 18 and for bypassing the outdoor side heat exchanger 3 and the four-way valve 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multi-chamber air conditioner having a plurality of indoor heat exchangers.

[0002]

2. Description of the Related Art FIG. 7 shows a refrigerant circuit diagram of a conventional multi-chamber air conditioner. In the figure, the outdoor unit 14 includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an outdoor expansion valve 16, a second outdoor expansion valve 15, and a flow control mechanism 17, while A plurality of, for example, four indoor units 9a to 9d each include an indoor expansion valve 10a (10b to 10d) and an indoor heat exchanger 11a (11b to 11d).

In such a configuration, during the heating operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is transmitted via the four-way valve 2 to the indoor heat exchangers 11a to 11d of the indoor units 9a to 9d.
In 1d, the refrigerant exchanges heat with the indoor air and is condensed to become a high-pressure liquid refrigerant. The refrigerant is decompressed by the outdoor expansion valve 16 on the outdoor unit 14 side through the indoor expansion valves 10a to 10d, and the second outdoor expansion valve 15
Then, it evaporates in the outdoor heat exchanger 3 to become a low-temperature low-pressure gas refrigerant, and then returns to the compressor 1 via the four-way valve 2.

At this time, if any of the indoor units 9a to 9d is in a stopped state, for example, if the indoor unit 9a is in a stopped state, the indoor expansion valve 1 in the indoor unit 9a
0a is slightly opened, and the operation is performed so that the refrigerant hardly flows into the indoor unit 9a.

On the other hand, in the heating operation under the high outdoor temperature condition, when all the indoor units 9a to 9d are in the operating state, the flow control mechanism 17 is closed, and the indoor expansion valves 10a to 10d are all opened, and the outdoor Expansion valve 16 and second outdoor expansion valve 1
5 controls the flow rate, the compressor 1 is operated at the upper limit capacity when the capacity is variable, and the capacity of the outdoor heat exchanger 3 and the capacity of the indoor heat exchangers 11a to 11d are balanced, and It is operated while maintaining the operating pressure.

Next, when only one of the indoor units 9a to 9d, for example, the indoor unit 9d is operated, the indoor units 9a to 9c
The indoor expansion valves 10a to 10c are slightly opened, and the indoor unit 9a
The compressor 1 is operated at the lower limit capacity while the flow rate is controlled by the indoor expansion valve 10 d of the indoor unit 9 d and the outdoor expansion valve 16 of the outdoor unit 14 while the refrigerant is hardly flowing through the compressor 1. Be driven. At this time, the evaporating pressure or the corresponding temperature in the outdoor heat exchanger 3 is detected, and when it is higher than the set value, the flow control mechanism 17 is opened, and the low-pressure refrigerant from the outdoor expansion valve 16 is supplied to the outdoor heat exchanger 3. The flow rate of the refrigerant flowing through the outdoor heat exchanger 3 and the bypass circuit 17a is controlled by adjusting the flow control mechanism 17 and the opening degree of the second outdoor expansion valve 15, and the evaporation capacity. Is controlled so that the evaporation pressure approaches a set value.

As described above, it is possible to suppress the rise of the low pressure during the heating operation, and to always maintain an appropriate operating pressure state throughout the year regardless of the number of operating indoor units 9a to 9d.

[0008]

However, in the conventional multi-chamber air conditioner as described above, when only one indoor unit is operated, the compressor 1 has the lower limit capacity as described above. Is the outdoor heat exchanger 3 and the bypass circuit 17
Since the refrigerant flows through both circuits a, the capacity of the outdoor heat exchanger 3 cannot be completely suppressed, that is, the heat absorption amount cannot be reduced to zero.

Therefore, the capacity of the indoor unit and the capacity of the compressor 1 on the outdoor unit side are severely unbalanced, for example, about 1:10, or the outdoor heat as an evaporator in a wide range of operation where the outdoor air condition is high. There is a possibility that the capacity of the exchanger 3 becomes excessive and the operating pressure rises abnormally.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a multi-room air conditioner, in which even when only some of the indoor units are operated, the outdoor heat is controlled. It is an object of the present invention to provide an air conditioner capable of reliably preventing the operating pressure of an exchanger from abnormally increasing.

[0011]

According to the first aspect of the present invention,
In an air conditioner that connects an outdoor unit having a compressor, a four-way valve, an accumulator, an outdoor heat exchanger, an outdoor expansion valve, and a plurality of indoor units, the outdoor unit is connected to the outdoor unit during a heating operation. An on-off valve provided on the upstream side of the expansion valve, a bypass circuit connecting the upstream side of the on-off valve during heating operation and the inlet side of the accumulator, and bypassing the outdoor heat exchanger and the four-way valve; An open / close adjusting means provided in the circuit for opening and closing the circuit and adjusting the flow rate is provided.

With this configuration, since the refrigerant does not flow into the outdoor heat exchanger by closing the on-off valve, heat absorption in the outdoor heat exchanger can be completely eliminated. The evaporator capacity is excessive even when the temperature is high or during a specific heating operation in which only a part of the indoor unit is operated and the capacity of the indoor unit becomes extremely unbalanced with respect to the outdoor function. And the operating pressure can be reliably prevented from abnormally increasing.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of the outdoor heat exchangers are arranged in parallel, and the outdoor expansion valve and the first on-off valve are connected to the plurality of outdoor heat exchangers. It is characterized in that it is provided for each heat exchanger.

With this configuration, in addition to the operation of the first aspect of the present invention, each outdoor heat exchanger is controlled by individually controlling the on-off valves provided for each of the plurality of outdoor heat exchangers arranged in parallel. By finely controlling the evaporating capacity of the vessel, fluctuations in high pressure and low pressure can be reduced.

According to a third aspect of the present invention, in the first aspect of the present invention, a subcooling coil provided between the on-off valve and a connection point of the bypass circuit, and the bypass circuit is connected to the first bypass. A second bypass circuit for connecting between the supercooling coil and the on-off valve 6 and between the refrigerant discharge side of the compressor 1 and the four-way valve 2; As means, a second bypass circuit is provided in the second bypass circuit for opening and closing the circuit and adjusting the flow rate.
And opening and closing adjusting means.

With such a configuration, in addition to the operation of the first aspect of the present invention, the operating pressure (high pressure) is reduced by heat radiation from the supercooling coil, and an appropriate operating pressure can be maintained. .

According to a fourth aspect of the present invention, in the third aspect of the present invention, a plurality of the outdoor heat exchangers are arranged in parallel, and the outdoor expansion valve, the first opening / closing valve, and the supercooling coil are provided. It is characterized by being provided for each of the plurality of outdoor heat exchangers.

According to this structure, in addition to the operation of the third aspect of the present invention, the on-off valves provided for each of the plurality of outdoor heat exchangers arranged in parallel are individually controlled, so that each outdoor heat exchange is performed. The operating pressure can be properly maintained over a wider range by finely controlling the evaporating capacity of the vessel and further combining an on-off valve for releasing heat with a supercooling coil.

According to a fifth aspect of the present invention, there is provided an air conditioner comprising an outdoor unit having a variable capacity compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve, and a plurality of indoor units. A bypass circuit that connects the discharge-side pipe and the suction-side pipe of the compressor to the outdoor unit and bypasses the compressor; and a bypass circuit that is disposed in the bypass circuit and that exceeds a predetermined pressure value range. Pressure detection means for detecting this, and opening / closing adjustment means provided in the bypass circuit for opening / closing the circuit and adjusting the flow rate. The capacity of the compressor is determined by the detection signal of the pressure detection means. A fixed amount is reduced, and after a predetermined time elapses, the bypass circuit is opened by the opening / closing adjustment unit, and the detection state of the pressure detection unit is released.

With such a configuration, the capacity of the compressor can be used to the maximum, and the pressure fluctuation in the compressor can be reduced by using an inexpensive pressure switch or the like as the detecting means.

According to a sixth aspect of the present invention, there is provided an air compressor comprising an outdoor unit having a plurality of compressors, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve connected in parallel, and a plurality of indoor units. In the harmony device, a bypass circuit that connects the discharge-side pipe and the suction-side pipe of the plurality of compressors to the outdoor unit to bypass the compressor, and a predetermined pressure value range that is disposed in the bypass circuit. A pressure detecting means for detecting the pressure when the pressure exceeds the limit, and an opening / closing adjusting means provided in the bypass circuit for opening / closing the circuit and adjusting the flow rate. The number of operating units is reduced, and after a lapse of a predetermined time, the opening / closing adjustment unit opens the bypass circuit to cancel the detection state of the pressure detection unit.

With such a configuration, the number of operating compressors can be controlled to maximize the capacity of the entire compressor, and an inexpensive pressure switch or the like can be used as a detecting means. Pressure fluctuation in the compressor can be reduced.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the refrigerant circuit, and the basic refrigerant cycle is the same as that shown in FIG. 7. Therefore, the same portions are denoted by the same reference numerals and description thereof will be omitted.

In the outdoor unit 14 ', a parallel circuit of the check valve 4 and the outdoor expansion valve 5 is used instead of the second outdoor expansion valve 15, and an open / close valve is used instead of the outdoor expansion valve 16. 6, the low-temperature and low-pressure gas refrigerant from the four-way valve 2 is returned to the compressor 1 via the accumulator 18.

Further, the bypass circuit 17a provided with the flow control mechanism 17 is eliminated, and the outlet sides of the indoor expansion valves 10a to 10d are connected to the space between the accumulator 18 and the four-way valve 2. It is assumed that a flow regulating pipe 13 is provided.

In the above configuration, during the cooling operation, the high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 1 exchanges heat with the indoor air in the outdoor heat exchanger 3 through the four-way valve 2. After being condensed to become a high-pressure liquid refrigerant and passing through the check valve 4, the pressure is reduced by the indoor expansion valves 10 a to 10 d on the indoor units 9 a to 9 d side via the open / close valve 6, and the indoor heat exchanger 11 a After evaporating at ~ 11d to become a low-temperature low-pressure gas refrigerant, the refrigerant enters the accumulator 18 via the four-way valve 2 on the outdoor unit 14 'side. Then, the non-vapor refrigerant is separated by the accumulator 18, and only the gas refrigerant is returned to the compressor 1 and compressed again.

In the heating operation, the high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 1 releases heat through the four-way valve 2 to the indoor heat exchangers 11a to 11d on the indoor units 9a to 9d side to condense. Is turned into a high-pressure liquid refrigerant, and the indoor expansion valve 10
a through 10d, the pressure is reduced by the outdoor expansion valve 5 through the open / close valve 6 on the outdoor unit 14 'side, and evaporated by the outdoor heat exchanger 3 to become a low-temperature low-pressure gas refrigerant. It enters the accumulator 18 via the four-way valve 2. Then, the non-vapor refrigerant is separated by the accumulator 18, and only the gas refrigerant is returned to the compressor 1 and compressed again.

At the time of a specific heating operation in which the high pressure and the low pressure are high, such as when the outside air temperature is high and when only a part of the indoor units 9a to 9d are operated, the evaporation pressure in the outdoor heat exchanger 3 or the equivalent temperature, Alternatively, the condensing pressure or the corresponding temperature in the indoor heat exchangers 11a to 11d on the indoor units 9a to 9d side is detected, and when the pressure is higher than the set value, the on-off valve 6 is closed,
Instead, the on-off valve 12 is opened. Therefore,
The high-pressure liquid refrigerant that has exited the indoor expansion valves 10a to 10d passes through the on-off valve 12, is decompressed by the flow control pipe 13, and directly enters the accumulator 18 as a low-pressure liquid / gas two-phase refrigerant. Then, while the liquid refrigerant is separated by the accumulator 18 and accumulates at the bottom thereof, the gas refrigerant is sucked and returned to the compressor 1 and is compressed again.

Since the refrigerant does not flow into the outdoor heat exchanger 3 by closing the on-off valve 6, the heat absorption in the outdoor heat exchanger 3 can be completely eliminated. Therefore, when the outside air temperature is high, or during a specific heating operation in which only a part of the indoor unit is operated and the capacity of the indoor unit becomes unbalanced with respect to the outdoor functional force, for example, 1:10. In addition, the capacity of the evaporator does not become excessive, and the operating pressure can be reliably prevented from abnormally increasing.

In FIG. 1, the indoor expansion valves 10a to 10a
The high-pressure liquid refrigerant that has exited 0d is supplied to the on-off valve 12,
Are flown to the accumulator 18 without passing through the outdoor heat exchanger 3, but a high pressure regulating valve which opens and closes at a predetermined pressure value may be used instead. The capacity issue of the outdoor heat exchanger 3 is detected by the pressure of the high-pressure liquid refrigerant, and the high-pressure control valve is operated.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows the refrigerant circuit, which is basically the same as that shown in FIG. 1 above. Therefore, the same parts are denoted by the same reference numerals and the description thereof will be omitted. Are also omitted from the drawings.

Thus, in the outdoor unit 14 ', two outdoor heat exchangers 3a, 3b are provided in parallel, each of which is provided with a check valve 4a, 4b, an outdoor expansion valve 5a, 5b, and an open / close valve 6a, 6b is provided.

In the above configuration, when the outside air temperature is high and when only a part of the indoor units 9a to 9d is operated,
During certain heating operations where high and low pressures are high,
The evaporating pressure or the corresponding temperature in the outdoor heat exchanger 3 or the condensing pressure or the corresponding temperature in the indoor heat exchangers 11a to 11d on the indoor units 9a to 9d side are detected. For example, the on-off valve 6a is closed, and the evaporation capacity in the outdoor heat exchanger 3a, that is, the amount of heat absorbed is eliminated.

Further, if the result of the detection is still higher than the set value, on the other hand, for example, the on-off valve 6b is closed, and the evaporation capacity in the outdoor heat exchanger 3b, that is, the heat absorption is also eliminated.

At this time, by simultaneously opening the on-off valve 12, the high-pressure liquid refrigerant that has exited the indoor expansion valves 10a to 10d passes through the on-off valve 12 and is decompressed by the flow control pipe 13, and the low-pressure liquid refrigerant is discharged. / The refrigerant enters the accumulator 18 directly as a two-phase refrigerant. And the accumulator 18
While the liquid refrigerant is separated and accumulates at the bottom thereof, the gas refrigerant is sucked back into the compressor 1 and is compressed again.

As described above, by individually controlling the two on-off valves 6a and 6b to finely control the evaporation capacity of the two outdoor heat exchangers 3a and 3b, the first embodiment will be described. In addition to the functions and effects described above, the fluctuations of the high pressure and the low pressure can be further reduced.

In FIG. 2 as well, a high-pressure regulating valve which opens and closes at a predetermined pressure value may be used in place of the on-off valve 12 and the flow regulating pipe 13, in which case the outdoor heat exchange as an evaporator is used. The capacity problem of the vessel 3 is detected by the pressure of the high-pressure liquid refrigerant, and the high-pressure regulating valve is operated.

(Third Embodiment) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows the refrigerant circuit, which is basically the same as that shown in FIG. 1 above. Therefore, the same parts will be denoted by the same reference numerals and description thereof will be omitted. A part of a circuit connected from the indoor heat exchanger of the indoor unit to the four-way valve 2 is also omitted from the drawing.

However, a supercooling coil 7 having the same structure as that of the outdoor heat exchanger 3 is provided on the side of the on-off valve 6 from a circuit connection point between the on-off valve 6 and the on-off valve 12. 7 and the on-off valve 6 are connected between the compressor 1 and the four-way valve 2 to bypass the four-way valve 2, the outdoor heat exchanger 3, the check valve 4, the outdoor expansion valve 5, and the on-off valve 6. A simple bypass circuit is provided, and an on-off valve 1 is provided on the compressor 1 side in the bypass circuit.
9 is provided with a flow control tube 20 on the side of the supercooling coil 7.

The supercooling coil 7 is obtained by dividing a part of the outdoor heat exchanger 3 and functionally operates integrally with the outdoor heat exchanger 3, but may be provided separately. Good.

In the above configuration, during the cooling operation, the high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 1 exchanges heat with the indoor air in the outdoor heat exchanger 3 through the four-way valve 2. After being condensed and turned into a high-pressure liquid refrigerant, passing through the check valve 4, it is passed through the open / close valve 6 to the supercooling coil 7, and further radiates heat to be supercooled.
After being decompressed by the indoor expansion valves 10a to 10d on the 9d side and evaporated by the indoor heat exchangers 11a to 11d to become low-temperature and low-pressure gas refrigerant, the refrigerant is supplied to the accumulator 18 via the four-way valve 2 on the outdoor unit 14 'side. enter. Then, the non-vapor refrigerant is separated by the accumulator 18, and only the gas refrigerant is returned to the compressor 1 and compressed again.

In the heating operation, the high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 1 releases heat through the four-way valve 2 to the indoor heat exchangers 11a to 11d on the indoor units 9a to 9d side to condense. Is turned into a high-pressure liquid refrigerant, and the indoor expansion valve 10
After the heat is again radiated, condensed, and supercooled by the supercooling coil 7 on the outdoor unit 14 'side through a to 10d, the pressure is reduced by the outdoor expansion valve 5 via the open / close valve 6, and the outdoor heat is reduced. After evaporating in the exchanger 3 to become a low-temperature and low-pressure gas refrigerant, the refrigerant enters the accumulator 18 via the four-way valve 2. Then, the non-vapor refrigerant is separated by the accumulator 18, and only the gas refrigerant is returned to the compressor 1 and compressed again.

Furthermore, when the outside air temperature is high and when the indoor units 9a to 9
During a specific heating operation in which the high pressure and the low pressure increase, such as when only a part of the 9d is operated, the evaporation pressure or the corresponding temperature in the outdoor heat exchanger 3, or the indoor heat exchanger 11a on the indoor units 9a to 9d side. When the pressure is higher than the set value, the on-off valve 6 is closed, the on-off valve 12 is opened instead, and the evaporation capacity in the outdoor heat exchanger 3 is detected. That is, the heat absorption is eliminated. Therefore, the high-pressure liquid refrigerant that has exited the indoor expansion valves 10a to 10d passes through the on-off valve 12, is decompressed by the flow control pipe 13, and directly enters the accumulator 18 as a low-pressure liquid / gas two-phase refrigerant. Then, while the liquid refrigerant is separated by the accumulator 18 and accumulates at the bottom thereof, the gas refrigerant is sucked and returned to the compressor 1 and is compressed again.

If the operating pressure (high pressure) further increases even after performing such an operation, the on-off valve 19 is changed from the previously closed state to the open state, and the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is discharged. Is flowed between the on-off valve 6 and the supercooling coil 7 via the on-off valve 19 and the flow control pipe 20. The gas refrigerant is radiated and condensed by the supercooling coil 7 to become a liquid refrigerant, and enters the accumulator 18 after being decompressed through the on-off valve 12 and the flow control pipe 13.

As described above, since the heat is radiated by the supercooling coil 7, the operating pressure (high pressure) is reduced, and an appropriate operating pressure is maintained. As in the case of the on-off valve 12 and the flow control pipe 13 in FIG. 1, a high-pressure pressure control valve that opens and closes at a predetermined pressure value may be used instead of the on-off valve 19 and the flow control pipe 20.

(Fourth Embodiment) Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 4 shows the refrigerant circuit, which is basically the same as that shown in FIG. 3 above. Therefore, the same portions are denoted by the same reference numerals and description thereof is omitted.

However, in this outdoor unit 14 ',
Two outdoor heat exchangers 3a and 3b are provided in parallel, and each of them is provided with check valves 4a and 4b, outdoor expansion valves 5a and 5b, and on-off valves 6a and 6b.

An external heat exchanger 3 having the same structure as that of the outdoor heat exchanger 3 is connected between a circuit connection point between the on-off valves 6a and 6b and a connection point of a bypass circuit provided with the on-off valve 12 on the on-off valve 6a side. The cooling coil 7a has the same configuration as that of the outdoor heat exchanger 3 between the circuit connection point between the on-off valves 6a and 6b and the connection point of the bypass circuit on which the flow control pipe 20 is arranged on the on-off valve 6b side. Of the supercooling coils 7b are respectively provided.

In the above configuration, when the outdoor air temperature is high and when a specific heating operation in which high pressure and low pressure are high, such as when only a part of the indoor units 9a to 9d are operated, the outdoor heat exchanger is used. 3 or the condensing pressure or the equivalent temperature in the indoor heat exchangers 11a to 11d on the indoor units 9a to 9d side, and closes one of the on-off valves 6b if it is higher than the set value. State and the outdoor heat exchanger 3b
, The heat absorption amount is eliminated, and the on-off valve 12 is opened instead. Therefore, the high-pressure liquid refrigerant that has exited the indoor expansion valves 10a to 10d passes through the on-off valve 12, is decompressed by the flow control pipe 13, and directly enters the accumulator 18 as a low-pressure liquid / gas two-phase refrigerant. Then, while the liquid refrigerant is separated by the accumulator 18 and accumulates at the bottom thereof, the gas refrigerant is sucked and returned to the compressor 1 and is compressed again.

If the operating pressure (high pressure) further increases even after such an operation, the on-off valve 19 is changed from the previously closed state to the open state, and the high-temperature high-pressure gas refrigerant discharged from the compressor 1 is discharged. Is flowed to the supercooling coils 7a and 7b via the on-off valve 19 and the flow control pipe 20. The gas refrigerant is radiated and condensed by these two supercooling coils 7a and 7b to become a liquid refrigerant, and after entering into the accumulator 18 after being depressurized through the on-off valve 12 and the flow control pipe 13.

As described above, by individually controlling the two opening / closing valves 6a and 6b, the evaporating capacity of the two outdoor heat exchangers 3a and 3b is finely controlled, and furthermore, the opening and closing are performed by radiating heat by the supercooling coils 7a and 7b. By combining the valve 19, the operating pressure can be properly maintained over a wider range than the operation and effect described in the third embodiment.

(Fifth Embodiment) Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 5 shows the refrigerant circuit, which is basically the same as that shown in FIG. 1 above. Therefore, the same parts will be denoted by the same reference numerals and description thereof will be omitted. Are also omitted from the drawings.

Thus, in the outdoor unit 14 ', FIG.
, The compressor 1 is of a variable capacity type, and its discharge side pipe 24 and suction side pipe 2
5 is provided with a bypass circuit for bypassing the compressor 1, and the opening / closing valve 23, the pressure switch 22, and the flow regulating pipe 21 are sequentially provided in the bypass circuit from the suction side pipe 25 side.
Is arranged.

The pressure switch 22 has a predetermined pressure set value A
As a result, the contact is opened, and a detection signal is output. On the other hand, the contact is closed when the pressure falls below the pressure set value B (B <A) at which a predetermined pressure drop has occurred by the differential. It is set so as to return and stop the output of the detection signal. For example, the operating pressure A at which the contacts are opened is 25 [kg / cm ² ], and the return pressure B at which the contacts are returned to the closed state is 20 [kg / cm ² ]. cm ² ].

In the above configuration, the on-off valve 23 is closed during normal cooling operation and heating operation. In a specific heating operation in which the high pressure is high, such as when the outside air temperature is high or when only a part of the indoor units 9a to 9d is operated, the high pressure in the discharge pipe 24 of the compressor 1 is changed to the flow control pipe 21. Is detected by the pressure switch 22 via the. If the detected pressure is equal to or higher than the operating pressure A, the contact of the pressure switch 22 is opened, and the capacity of the compressor 1 is reduced by a predetermined amount according to the detection signal.

After a lapse of a predetermined time, the on-off valve 23 is opened to lower the pressure value at the pressure switch 22 with the low pressure in the suction side pipe 25 of the compressor 1 so that the pressure becomes equal to or lower than the return pressure B. Then, the contact of the pressure switch 22 is closed again, and the capacity of the compressor 1 is increased by the reduced predetermined amount according to the detection signal.

Thereafter, by closing the on-off valve 23, the pressure switch 22 detects that the high pressure of the discharge side pipe 24 becomes the operating pressure A. If the high-pressure pressure has reached the operating pressure A due to the decrease in the capacity of the compressor 1, the capacity of the compressor 1 is reduced again by a predetermined amount, and the above operation is repeatedly executed.

By controlling the compressor 1 in this manner, the capacity of the compressor 1 can be maximized,
The high-pressure pressure can be detected by the inexpensive pressure switch 22 and the pressure fluctuation can be reduced.

In the pressure switch 22,
The capacity of the compressor 1 is reduced by detecting that the high pressure on the discharge pipe 24 side is equal to or higher than a predetermined set value, but the flow rate control pipe 21 and the on-off valve 23 are interposed with the pressure switch 22 interposed therebetween. The installation position may be replaced, and the capacity of the compressor 1 may be reduced by detecting that the low pressure on the suction side pipe 25 side becomes equal to or less than a predetermined set value.

In this case as well, by controlling the compressor 1, the capacity of the compressor 1 can be maximized, and the low-pressure pressure can be detected by the inexpensive pressure switch 22 to reduce the pressure fluctuation. Can be done.

(Sixth Embodiment) Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 6 (1) shows the refrigerant circuit, which is basically the same as that shown in FIG. 5, and therefore, the same parts will be denoted by the same reference characters and description thereof will be omitted.

In the outdoor unit 14 ', a plurality of, for example, two compressors 1a and 1b are provided in parallel, and the discharge side pipe 24 and the suction side pipe 25 are connected to each other to connect these compressors. A bypass circuit for bypassing 1a and 1b is provided, and an on-off valve 23, a pressure switch 22, and a flow control pipe 21 are arranged in this bypass circuit in order from the suction side pipe 25 side.

The pressure switch 22 has a predetermined pressure set value A
As a result, the contact is opened, and a detection signal is output. On the other hand, the contact is closed when the pressure falls below the pressure set value B (B <A) at which a predetermined pressure drop has occurred by the differential. It is set so as to return and stop the output of the detection signal. For example, the operating pressure A at which the contacts are opened is 25 [kg / cm ² ], and the return pressure B at which the contacts are returned to the closed state is 20 [kg / cm ² ]. cm ² ].

In the above configuration, the on-off valve 23 is closed during normal cooling operation and heating operation. In a specific heating operation in which the high pressure is high, such as when the outside air temperature is high or when only a part of the indoor units 9a to 9d is operated, the high pressure in the discharge pipe 24 of the compressor 1 is changed to the flow control pipe 21. Is detected by the pressure switch 22 via the. When the detected pressure is equal to or higher than the operating pressure A, the contact of the pressure switch 22 is opened, and one of the compressors 1a and 1b is stopped by the detection signal.

After a lapse of a predetermined time, the on-off valve 23 is opened to lower the pressure value at the pressure switch 22 with the low pressure in the suction side pipe 25, and the pressure switch is returned to the return pressure B or lower. 22 contacts are closed,
One of the compressors 1a and 1b which has been stopped is started by the detection signal.

Thereafter, by closing the on-off valve 23, the pressure switch 22 detects that the high pressure of the discharge pipe 24 becomes the operating pressure A. If one of the compressors 1a and 1b stops, and the high pressure reaches the operating pressure A, one of the compressors 1a and 1b is stopped again, and the above operation is repeatedly executed.

It is also conceivable that, with a configuration substantially similar to that of FIG. 6A, low pressure is controlled instead of high pressure. FIG. 6 (2) is a modification of the configuration shown in FIG. 6 (2), in which the discharge side pipe 24 and the suction side pipe 25 are connected to each other to
a, a bypass circuit for bypassing the flow path a, 1b is provided in the bypass circuit.
A pressure switch 22 'and an on-off valve 23 are provided.

The pressure switch 22 'is opened when the contact is below a predetermined pressure set value C, and outputs a detection signal. On the other hand, the pressure switch 22' is a pressure set value at which a predetermined pressure rise is caused by the differential. It is assumed that the setting is made so as to return to the closed state at D (D> C) and stop the output of the detection signal.

In the above configuration, the on-off valve 23 is closed during normal cooling operation and heating operation. Also, during a specific heating operation in which the low pressure is low, such as when the outside air temperature is high or when only a part of the indoor units 9a to 9d is operated, the low pressure in the suction side pipe 25 of the compressor 1 is reduced by the flow control pipe 21. Is detected by the pressure switch 22 'via the. When the detected pressure is equal to or lower than the operating pressure C, the contact of the pressure switch 22 'is opened, and one of the compressors 1a and 1b is stopped by the detection signal.

After a lapse of a predetermined time, by opening the on-off valve 23, the pressure value at the pressure switch 22 'is increased by the high pressure in the discharge side pipe 24, and the pressure is again increased to the return pressure D or more. The contacts of the switch 22 'are closed and the compressors 1a, 1
Activate one of b.

Thereafter, by closing the on-off valve 23, the pressure switch 22 'detects that the low pressure of the suction side pipe 25 becomes lower than the operating pressure C. If one of the compressors 1a and 1b is stopped and the low pressure reaches the operating pressure C, one of the compressors 1a and 1b is stopped again, and the above operation is repeatedly executed.

In this way, the plurality of compressors 1a, 1
b, the number of compressors 1a, 1b
Of each of the compressors 1a, 1a,
The capacity of the whole 1b can be used to the maximum, and high-pressure pressure or low-pressure pressure can be detected by inexpensive pressure switches 22 and 22 ', and the pressure fluctuation can be reduced.

[0073]

According to the first aspect of the invention, since the refrigerant does not flow into the outdoor heat exchanger by closing the on-off valve, heat absorption in the outdoor heat exchanger can be completely eliminated. Even when the outdoor temperature is high, or during a specific heating operation in which only a part of the indoor unit is operated and the capacity of the indoor unit is very Is not excessive, and an abnormal increase in the operating pressure can be reliably prevented.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, each of the plurality of outdoor heat exchangers arranged in parallel is individually controlled by an on-off valve to thereby control each of the outdoor heat exchangers. By finely controlling the evaporation capacity in the heat exchanger, fluctuations in high pressure and low pressure can be further reduced.

According to the third aspect of the invention, in addition to the effect of the first aspect of the present invention, the operating pressure (high pressure) is reduced by the heat radiation from the supercooling coil, and the proper operating pressure is maintained. Can be.

According to the fourth aspect of the invention, in addition to the effects of the third aspect of the present invention, the on-off valves provided for each of the plurality of outdoor heat exchangers arranged in parallel are individually controlled, so that each outdoor By finely controlling the evaporating capacity of the heat exchanger and further combining an on-off valve for releasing heat with a supercooling coil, the operating pressure can be appropriately maintained over a wider range.

According to the fifth aspect of the present invention, the capacity of the compressor can be maximized, and the pressure fluctuation in the compressor can be reduced by using an inexpensive pressure switch or the like as a detecting means. it can.

According to the present invention, the number of operating compressors can be controlled to maximize the capacity of the entire compressor, and an inexpensive pressure switch or the like can be used as the detecting means. Pressure fluctuations in the compressor can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a refrigerant circuit according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a refrigerant circuit according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a refrigerant circuit according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a refrigerant circuit according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a refrigerant circuit according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a refrigerant circuit according to a sixth embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a refrigerant circuit of a conventional multi-chamber air conditioner.

[Explanation of symbols]

 1, 1a, 1b Compressor 2 Four-way valve 3, 3a, 3b Outdoor heat exchanger 4 Check valve 5 Outdoor expansion valve 6 On-off valve 7, 7a, 7b Supercooling coils 9a to 9d Indoor units 10a to 10d ... indoor expansion valves 11a to 11d ... indoor heat exchangers 12 ... on-off valves 13 ... flow control tubes 14, 14 '... outdoor units 15 ... second outdoor expansion valves 16 ... outdoor expansion valves 17 ... flow rates Control mechanism 17a: bypass circuit 18: accumulator 19: open / close valve 20: flow control pipe 21: flow control pipe 22, 22 'pressure switch 23: open / close valve 24: discharge side pipe 25: suction side pipe

Claims (6)

[Claims] An air conditioner comprising: an outdoor unit having a compressor, a four-way valve, an accumulator, an outdoor heat exchanger, an outdoor expansion valve, and a plurality of indoor units. An on-off valve provided on the upstream side of the outdoor expansion valve during operation; and a bypass connecting the upstream side of the on-off valve during heating operation and the inlet side of the accumulator to bypass the outdoor heat exchanger and the four-way valve. An air conditioner comprising: a circuit; and an opening / closing adjusting means provided in the bypass circuit for opening / closing the circuit and adjusting the flow rate. 2. The outdoor heat exchanger according to claim 1, wherein a plurality of the outdoor heat exchangers are arranged in parallel, and the outdoor expansion valve and the first on-off valve are provided for each of the plurality of outdoor heat exchangers. Air conditioner. 3. A supercooling coil provided between the on-off valve and a connection point of the bypass circuit, a first bypass circuit for the bypass circuit, a supercooling coil between the supercooling coil and the on-off valve 6, and A second bypass circuit that connects between the refrigerant discharge side of the compressor 1 and the four-way valve 2;
The air conditioner according to claim 1, further comprising a second opening / closing adjusting means provided in the bypass circuit for opening / closing the circuit and adjusting the flow rate. 4. A plurality of said outdoor heat exchangers are arranged in parallel, and said outdoor expansion valve, said first opening / closing valve and a supercooling coil are provided for each of said plural outdoor heat exchangers. The air conditioner according to claim 3. 5. An air conditioner comprising: an outdoor unit having a variable capacity compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve, and a plurality of indoor units, wherein the outdoor unit includes: A bypass circuit that connects the discharge-side pipe and the suction-side pipe of the compressor to bypass the compressor, and a pressure that is provided in the bypass circuit and that detects when the pressure exceeds a predetermined pressure value range. Detecting means, provided in the bypass circuit, opening and closing adjusting means for opening and closing the circuit and adjusting the flow rate, the capacity of the compressor is reduced by a predetermined amount by a detection signal of the pressure detecting means,
An air conditioner, wherein after a lapse of a predetermined time, the bypass circuit is opened by the opening / closing adjustment means and the detection state by the pressure detection means is released. 6. A plurality of compressors connected in parallel, a four-way valve,
An outdoor unit having an outdoor heat exchanger, an outdoor unit having an outdoor expansion valve, and a plurality of indoor units, wherein the outdoor unit includes a discharge pipe and a suction pipe of the plurality of compressors. A bypass circuit connected to the bypass circuit to bypass the compressor; a pressure detection means provided in the bypass circuit for detecting when the pressure value exceeds a predetermined pressure value range; and a circuit provided in the bypass circuit. Opening / closing adjustment means for performing opening / closing and flow rate adjustment, reducing the number of operating compressors according to the detection signal of the pressure detection means, and opening / closing the bypass circuit by the opening / closing adjustment means after a lapse of a predetermined time. An air conditioner, wherein the detection state of the pressure detection means is released.