JP2705044B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner provided with a plurality of air conditioning units having a plurality of indoor units.

[0002]

2. Description of the Related Art Various conventional air conditioners having a plurality of indoor units have already been developed.
For example, there is an air conditioning unit as shown in Refrigeration, Vol. 61, No. 708 (October 1986), pp. 1038 to 1045.

The basic technology is as shown in FIG.
The compressor 2, the four-way valve 3, the outdoor heat exchanger 4, and the outdoor expansion valve 5 installed in the outdoor unit 1 and the indoor unit 6 installed in parallel with the outdoor unit 1. The inner expansion valve 7 and the indoor heat exchanger 8 are sequentially connected in a ring shape to constitute a heat pump refrigeration cycle.

The capacity of the compressor 2 is variable, and the amount of circulation of the refrigerant in the refrigeration cycle can be changed by changing the frequency of the supplied power.

The four-way valve 3 switches between a cooling operation and a heating operation. During the cooling operation, the refrigerant flows in the direction of the solid line arrow in FIG. 5 to form a cooling cycle. The refrigerant flows through to form a heating cycle.

An outdoor blower 9 and an indoor blower 10 are installed close to the outdoor heat exchanger 4 and the indoor heat exchanger 8, respectively.

In such an air conditioning unit, a plurality of, for example, three indoor units 6a, 6b, 6c can be individually operated, and when only the indoor unit 6a is operated, the other indoor units 6b, 6b, 6c are operated. In 6c, the indoor expansion valves 7b and 7c are fully closed, and the indoor blowers 10b and 10c are also stopped. At this time, the capacity of the compressor 2 is controlled by an inverter or the like, and the compressor 2 can be individually operated with a capacity corresponding to the number of operating indoor units.

Further, when it is necessary to install 6, 9 or more indoor units in a building or the like, for example, in the case of 6 indoor units, as shown in FIGS. 6 (a) and 6 (b). To
In an air conditioner in which two air conditioning units I and II are installed, it is possible to cope by operating each air conditioning unit individually.

[0009]

However, in the above-mentioned prior art, the air conditioning units I and II are operated individually and independently, that is, the air conditioning units I and II are separately operated.
Transfer of heat between II is not possible.

That is, when the heat loads of the air conditioning units I and II are different, for example, the air conditioning unit I has insufficient air conditioning capacity and the air conditioning unit II cannot handle the excess air conditioning capacity. It had the disadvantage that the comfort of each room in unit II was impaired.

When designing an air conditioner in the above-mentioned conventional example, the air conditioning capacity of the air conditioning unit I generally depends on the heat load at the time of peaking on the air conditioning unit I side.
The air conditioning capacity of II is designed to correspond to the heat load at the time of the peak of the air conditioning unit II.

Therefore, if the peak time of the thermal load on the air conditioning unit I and the peak on the thermal load on the II side are different from each other, it means that the equipment is excessive except at the time of the peak, and the equipment cost becomes high.
In addition, there is a disadvantage that the cost of contracting power with a power company is also high.

Further, in the above-mentioned conventional example, since the power to be used is the daytime power in which the air conditioner is mainly used, from the social point of view that the usage of electronic equipment is increasing year by year, a high load is imposed. There is a drawback that the peak of the power consumption reaches an extreme state at the time and the power supply capability may be exceeded.

Therefore, the present invention solves the conventional problem, and not only reduces the capacity of air conditioning equipment by enabling heat transfer between air conditioning units of different systems, but also reduces the cost of contract power with a power company. It is an object of the present invention to provide an air conditioner that can reduce power consumption, suppress peak power consumption at high load times in the daytime, and contribute to leveling of power usage.

[0015]

To achieve the above object, an air conditioner according to the present invention comprises a plurality of air conditioning units and a heat exchange circuit.

The air conditioning unit constitutes a refrigerating cycle comprising a compressor, a four-way valve, a heat source side heat exchanger, a heat source side pressure reducing device, a load side pressure reducing device, and a load side heat exchanger connected in a ring. doing.

The heat exchange circuit is configured by connecting a refrigerant heat exchanger common to each of a plurality of air conditioning units and a pressure reducing device for the refrigerant heat exchanger in series. Then, a heat exchange circuit is connected between the heat source side pressure reducing device and the load side pressure reducing device of each air conditioning unit via the refrigerant flow switching device.

Further, the refrigerant heat exchanger, the load side heat exchanger and the four-way valve are connected by a bypass circuit having a bypass valve.

Further, the apparatus is provided with a control device for setting all the plurality of air conditioning units to the same operation mode (cooling or heating operation).

An air conditioner according to another aspect of the present invention includes a control device for setting a plurality of air conditioning units to different operation modes (cooling or heating operation).

[0021]

In the air conditioner of the present invention, first, a case where all the plurality of air conditioning units are set to the same operation mode (cooling or heating operation) will be described.

In this case, in the air conditioning operation of the plurality of air conditioning units, each refrigerant flow switching device is switched, the opening of the expansion valve for the refrigerant heat exchanger is controlled, and the heat exchange circuit and each refrigeration cycle are communicated. By controlling and operating the heat source side expansion valve, the expansion valve for the refrigerant heat exchanger, the load side expansion valve, and the bypass valve, the transfer of heat held by the refrigerant in each refrigeration cycle via the refrigerant heat exchanger Becomes possible.

That is, it is not necessary for each air conditioning unit to set the equipment capacity corresponding to the peak value of the sum of the indoor air conditioning loads in which the air conditioning units are installed. It suffices to set the equipment capacity shared by the air conditioning units, so that not only can the equipment capacity be reduced, but also the cost of contract power with a power company can be reduced.

Next, a case where a plurality of air conditioning units are set to different operation modes (cooling or heating operation) will be described.

In this case, in the air-conditioning operation of the plurality of air-conditioning units, by switching each refrigerant flow switching device to communicate the heat exchange circuit and each refrigeration cycle, the air-conditioning units having the opposite operation modes are operated in the air-conditioning operation. A so-called heat recovery operation, in which the exhaust heat of another air conditioning unit can be used as an auxiliary heat source instead of an air heat source at the time of performing a heat recovery operation, thereby suppressing the peak of daytime power consumption And can contribute to the leveling of power use.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of an air conditioner according to the present invention will be described with reference to the drawings. The same components as those in the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a refrigeration system diagram of an air conditioner according to a first embodiment of the present invention. FIG. 2 is an air conditioning load curve diagram with respect to time of day.

In FIG. 1, the air conditioner comprises a refrigeration cycle A of a two-system air conditioning unit I, a refrigeration cycle B of an air conditioning unit II, and a heat exchange circuit C. It is assumed that they are composed of the same device.

The air conditioning units I and II comprise an outdoor unit 1 and three indoor units 6a, 6b and 6c.
Four-way valve 3, outdoor heat exchanger 4, outdoor expansion valve 5, indoor expansion valves 7a, 7b, 7c, indoor heat exchangers 8a, 8b,
The refrigeration cycles A and B are formed by connecting the refrigeration cycles 8c in a ring shape.

The heat exchange circuit C includes an expansion valve E for a refrigerant heat exchanger.
V and a refrigerant heat exchanger HE common to each of the air conditioning units I and II are connected in series.

Here, in the heat exchange circuit C, a two-way valve KV for switching the refrigerant flow path is installed between the outdoor expansion valve 5 and the indoor units 6a, 6b, 6c in the refrigeration cycles A, B. , Two-way valve KV.

The refrigerant heat exchanger HE is connected to the first heat exchange section 1.
2, the second heat exchange section 13 and the first heat exchange section 12
And a bypass circuit E in which the indoor heat exchangers 8a, 8b, 8c and the four-way valve are connected via a bypass valve BV.
Is installed.

Further, the three indoor units 6a, 6b, 6c
The indoor heat exchangers 8a, 8b, 8c, the indoor expansion valves 7a,
7b, 7c, and indoor blowers 10a, 10b, 10
c.

The air conditioning unit I and the air conditioning unit II
Are operated in the same mode (cooling or heating) so that the four-way valve 3, the outdoor expansion valve 5, and the indoor expansion valves 7a, 7
b, 7c, the two-way valve KV, the expansion valve EV for the refrigerant heat exchanger, and the control device CN1 connected to the bypass valve BV by a signal line.
Is installed.

In FIG. 2, L1 and L2 indicate time transition curves of the sum of the air-conditioning loads in the rooms where the air-conditioning units I and II are installed, and Qmax indicates the air-conditioning units I and I.
Indicates the maximum air conditioning capacity of I.

The operation of the air conditioner configured as described above will be described below. The mode of the four-way valve 3 is such that the discharge side of the compressor 2 and the outdoor heat exchanger 4 are
In the case where the suction side of the compressor 2 communicates with the indoor unit 6, the cooling mode is used, the discharge side of the compressor 2 and the indoor unit 6 are connected, and the suction side of the compressor 2 and the outdoor heat exchanger 4 are connected. The case of communication is defined as a heating mode.

The operation of each component of the air conditioner of this embodiment in each case will be described with reference to Table 1 below.

[0038]

[Table 1] (A) In the case of not performing heat transfer between the systems of the air conditioning units I and II during normal daytime operation In this case, the two-way valve KV is opened and the bypass valve BV is closed by a signal from the control device CN1. (A-1) Cooling mode Four-way valve 3: cooling mode in response to a signal from controller CN1
, Outdoor expansion valve 5: fully open, indoor expansion valves 7a, 7
b, 7c: Predetermined opening degree. At this time, the high-temperature and high-pressure gas refrigerant sent from the compressor 2 is condensed in the outdoor heat exchanger 4 and decompressed by the indoor expansion valve 7 to be in a liquid or two-phase state. After evaporating in the pipes 8a, 8b and 8c and absorbing heat from the indoor air (cooling operation), it returns to the compressor 2 as superheated gas. (A-2) Heating mode Four-way valve 3: heating mode by signal from control device CN1
, Outdoor expansion valve 5: predetermined opening degree, indoor expansion valve 7a,
7b, 7c: Fully open. At this time, the high-temperature and high-pressure refrigerant sent from the compressor 2 is supplied to the indoor heat exchangers 8a, 8b and 8c.
After being condensed in the pipe and radiating heat to the indoor air (heating operation), the pressure is reduced by the outdoor expansion valve 5 to become a liquid or a two-phase state, and is evaporated in the pipe of the outdoor heat exchanger 4 to generate a superheated gas. And returns to the compressor 2. (B) In the daytime operation, heat transfer between the systems of the air conditioning units I and II is performed. (B-1) Both the air conditioning units I and II are in cooling operation. First, the air conditioning load curve at time τ1 to τ2 in FIG. , The sum L1 of the air-conditioning loads in each room on the air-conditioning unit I side is larger than the maximum air-conditioning capacity Qmax of the air-conditioning unit I, and the air-conditioning unit II has a surplus air-conditioning capacity. The case of heat transfer from I to II will be described.

Based on a signal from the control unit CN1, the four-way valve 3: cooling mode, the outdoor expansion valve 5: fully open, and the indoor expansion valves 7a, 7b, 7c: predetermined opening degrees.

Further, according to a signal from the control device CN1,
In the air conditioning unit I, the two-way valve KV: closed, the bypass valve BV: open, and the expansion valve EV for the refrigerant heat exchanger EV: fully open, while in the air conditioning unit II, the two-way valve KV: closed, the bypass valve B
V: Open, expansion valve for refrigerant heat exchanger EV: Set to a predetermined opening.

In this case, in the refrigerant heat exchanger HE, after leaving the outdoor heat exchanger 4 of the air conditioning unit I, the high-temperature and high-pressure liquid refrigerant flowing into the refrigerant heat exchanger HE and the air conditioning unit II
After exiting the outdoor heat exchanger 4, the expansion valve E for the refrigerant heat exchanger
V, the refrigerant flows into the refrigerant heat exchanger HE, and exchanges heat with the low-temperature, low-pressure two-phase refrigerant evaporated in the second heat exchange unit 13 of the refrigerant heat exchanger HE.
Heat transfer between systems to II is possible.

That is, the degree of supercooling of the air conditioning unit I is increased by the excess cooling capacity of the air conditioning unit II, the cooling capacity of the indoor units 6a, 6b, 6c can be increased, and the cooling load of the air conditioning unit I can be handled. Can be.

Conversely, as shown by the air conditioning load curve from time τ3 to time τ4 in FIG.
Of the air conditioning load in each room on the side of the air conditioning unit II than L2
Similarly, when the air conditioning unit I has excess air conditioning capacity, that is, when heat is transferred from the air conditioning unit II to I, excess air conditioning capacity of the air conditioning unit I The degree of cooling, that is, the cooling capacity can be increased, and it is possible to cope with the cooling load of the air conditioning unit II. (B-2) In the case where both the air conditioning units I and II are in the heating operation First, similarly to the case in the cooling operation, when the air conditioning unit II has the surplus air conditioning capacity, that is, heat is transferred from the air conditioning unit II to I. The case will be described.

According to a signal from the control unit CN1, the four-way valve 3: heating mode, the outdoor expansion valve 5: predetermined opening, and the indoor expansion valves 7a, 7b, 7c: predetermined opening.

In the air conditioning unit I, the two-way valve: closed, the bypass BV: closed, and the expansion valve E for the refrigerant heat exchanger
V: Fully open, while air conditioning unit II has two-way valve: closed,
Bypass BV: open, expansion valve EV for refrigerant heat exchanger: fully open.

In this case, in the refrigerant heat exchanger HE, after the compressor 2 of the air conditioning unit II is discharged, the high-temperature and high-pressure gas refrigerant flowing into the refrigerant heat exchanger HE via the bypass valve BV and the indoor expansion of the air conditioning unit I The pressure is reduced by the valves 7a, 7b, 7c, and the low-temperature, low-pressure two-phase refrigerant that has flowed into the refrigerant heat exchanger HE exchanges heat, so that heat transfer between the systems from the air conditioning units II to I becomes possible.

That is, the excess heating capacity of the air conditioning unit II is compensated for by the insufficient evaporation capacity of the air conditioning unit I, that is, the heating capacity is increased, and the heating load of the air conditioning unit I can be handled.

Conversely, as shown by the load curve between times τ1 and τ2 in FIG. 2, the case where the air conditioning unit I has excess air conditioning capacity, that is, the case where heat is transferred from the air conditioning unit II to I, is also considered. Similarly, the excess heating capacity of the air conditioning unit I can increase the evaporation capacity of the air conditioning unit II, that is, increase the heating capacity, and can cope with the heating load of the air conditioning unit II.

As described above, in the air conditioner of this embodiment, when all the two air conditioning units I and II are in the same operation mode (cooling or heating operation), the air conditioning units I and II operate in the air conditioning operation. The switching control of each two-way valve KV and the bypass valve BV, the outdoor expansion valve 5, and the indoor expansion valves 7a, 7b, 7 are performed based on signals from the control device CN1.
c, by controlling the opening degree of the expansion valve EV for the refrigerant heat exchanger and connecting the refrigeration cycles A and B to the heat exchange circuit C, the refrigerant in the refrigeration cycles A and B via the refrigerant heat exchanger HE. Transfer of the retained heat becomes possible.

That is, it is not necessary for each air conditioning unit to set the equipment capacity corresponding to the peak value of the sum of the indoor air conditioning loads in which the air conditioning units are installed. It suffices to set the equipment capacity shared by the air conditioning units, so that not only can the equipment capacity be reduced, but also the cost of contract power with a power company can be reduced.

Next, a description will be given of a second embodiment of the air conditioner according to the present invention. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 3 is a refrigeration system diagram of an air conditioner according to a second embodiment of the present invention. In FIG. 3, the four-way valve 3, the outdoor expansion valve 5, the indoor expansion valves 7a, 7b, 7c, the two-way valve, and the air conditioning unit I and the air conditioning unit II operate in different modes (cooling or heating). A control device CN2 connected to the KV, the refrigerant heat exchanger expansion valve EV, and the bypass valve BV via a signal line is provided.

The operation of the air conditioner configured as described above will be described below with reference to the operating states of the respective components (Table 2).

[0054]

[Table 2] (A ′) In the case of normal daytime operation and no heat transfer between the systems of the air conditioning units I and II In this case, the control device CN2
From the two-way valve KV: open, the bypass valve BV:
Closed. (A'-1) Air conditioning unit I: cooling mode, air conditioning unit I
I: Heating mode For the air conditioning unit I, the four-way valve 3: cooling mode, outdoor expansion valve 5: fully open, indoor expansion valves 7a, 7b, 7c: predetermined opening degree according to a signal from the control unit CN2. Is controlled.

At this time, the high-temperature and high-pressure gas refrigerant sent from the compressor 2 is condensed in the outdoor heat exchanger 4 and decompressed by the indoor expansion valve 7 to be in a liquid or two-phase state. After evaporating in the tubes of the heat exchangers 8a, 8b and 8c and absorbing heat from the indoor air (cooling operation), the gas returns to the compressor 2 as a superheated gas.

On the other hand, for the air conditioning unit II, the four-way valve 3: heating mode, outdoor expansion valve 5: predetermined opening degree, indoor expansion valves 7a, 7b,
7c: Controlled to fully open.

At this time, the high-temperature and high-pressure refrigerant sent from the compressor 2 is condensed in the tubes of the indoor heat exchangers 8a, 8b and 8c and radiates heat to the indoor air (heating operation), and then the outdoor expansion valve At 5, the pressure is reduced to a liquid or two-phase state, evaporated in the pipe of the outdoor heat exchanger 4, returned to the compressor 2 as a superheated gas. (A'-2) Air conditioning unit I: heating mode, air conditioning unit I
I: Cooling mode In this case, since only the air conditioning units I and II in the case of (B'-1) are reversed, detailed description will be omitted. (B ′) Case of performing heat transfer between systems of air conditioning units I and II during daytime operation In this case, two types of operation modes of each air conditioning unit can be considered, but as in the case of (A′-2), air conditioning is performed. Since the units I and II are only reversed, the air conditioning unit I: cooling mode
Only the case of the air conditioner unit II: heating mode will be described, and the description of the air conditioner unit I: heating mode and air conditioner unit II: cooling mode will be omitted.

For the air conditioning unit I, the control unit CN
According to the signal from 2, the four-way valve 3: cooling mode, the outdoor expansion valve 5: fully open, the indoor expansion valves 7a, 7b, 7c: a predetermined opening degree, the two-way valve KV: closed, the bypass valve BV: closed, refrigerant Expansion valve EV for heat exchanger: Control as if fully open.

On the other hand, for the air conditioning unit II, the four-way valve 3: heating mode, outdoor expansion valve 5: predetermined opening degree, indoor expansion valves 7a, 7b,
7c: predetermined opening degree, two-way valve KV: closed, bypass valve BV:
Closed, expansion valve EV for refrigerant heat exchanger: Controlled to be fully open.

In this case, in the refrigerant heat exchanger HE, after leaving the outdoor heat exchanger 4 of the air conditioning unit I, the high-temperature and high-pressure liquid refrigerant flowing into the refrigerant heat exchanger HE and the air conditioning unit II
After exiting the indoor heat exchangers 8a, 8b, 8c, the pressure is reduced by the indoor expansion valves 7a, 7b, 7c and the refrigerant heat exchanger H
The heat exchange between the low-temperature and low-pressure two-phase refrigerant that flows into E and evaporates in the second heat exchange unit 13 of the refrigerant heat exchanger HE,
Heat transfer between systems from the air conditioning units I to II becomes possible.

That is, the condensing capacity required in the air conditioning unit I is recovered by the evaporating capacity required in the air conditioning unit II via the refrigerant heat exchanger HE.
Heat recovery operation can be performed, and energy saving operation can be performed.

As described above, in the air conditioner of this embodiment, when the two air conditioning units I and II are in different operation modes (cooling or heating operation), the air conditioning units I and II perform the air conditioning operation. In response to a signal from the control device CN2, switching control of each two-way valve KV and bypass valve BV, the outdoor expansion valve 5, the indoor expansion valves 7a, 7b, 7
c) The opening degree of the refrigerant heat exchanger expansion valve EV is controlled so that the heat exchange circuit C communicates with each of the refrigeration cycles A and B.

As a result, the heat held by the refrigerant in the refrigeration cycles A and B can be transferred via the refrigerant heat exchanger HE.

That is, via the refrigerant heat exchanger HE, heat (condensation (or evaporation) capacity required in the air conditioning unit I is recovered by evaporation (or condensation) capacity required in the air conditioning unit II. Recovery operation can be performed, and energy-saving operation can be performed.

In the first and second embodiments, a pulse-type electric expansion valve having a fully-closed function as the refrigerant heat exchanger expansion valve EV, and a one-way valve for switching the refrigerant flow path.
The heat exchange circuit C was constituted by the two two-way valves.

However, as shown in FIG. 4, even when the temperature-type expansion valve EV1 having no fully closed function is used as the expansion valve for the refrigerant heat exchanger, not only the same effect as described above can be obtained, but also a two-way expansion valve can be obtained. Although it is necessary to additionally install the valve KV1, there is an effect that the cost of parts is significantly reduced and the control circuit is simpler.

[0067]

As described above, the present invention comprises a plurality of air conditioning units and a heat exchange circuit.

The air conditioning unit constitutes a refrigeration cycle comprising a compressor, a four-way valve, a heat source side heat exchanger, a heat source side pressure reducing device, a load side pressure reducing device, and a load side heat exchanger connected in a ring. The heat exchange circuit is configured by connecting a refrigerant heat exchanger common to each of the plurality of air conditioning units and a pressure reducing device for the refrigerant heat exchanger in series.

Then, a heat exchange circuit is connected between the heat source side pressure reducing device and the load side pressure reducing device of each air conditioning unit via a refrigerant flow switching device.

The refrigerant heat exchanger, the load side heat exchanger and the four-way valve are connected by a bypass circuit having a bypass valve.

Further, the system is provided with a control device for setting all the plurality of air conditioning units to the same operation mode.

In the above configuration, in the air conditioning operation of the plurality of air conditioning units, the switching control of each refrigerant flow path switching device, the bypass valve, the heat source side pressure reducing device, the load side pressure reducing device, the refrigerant heat By controlling the opening degree of the pressure reducing device for the exchanger and connecting the refrigeration cycle with the heat exchange circuit, the heat held by the refrigerant in the refrigeration cycle can be transferred via the refrigerant heat exchanger.

That is, it is not necessary for each air conditioning unit to set the equipment capacity in accordance with the peak value of the sum of the indoor air conditioning loads in which the air conditioning units are installed. It suffices to set the equipment capacity shared by the air conditioning units, so that not only can the equipment capacity be reduced, but also the cost of contract power with a power company can be reduced.

Another embodiment of the present invention is provided with a control device for setting a plurality of air conditioning units to different operation modes.

In this case, in the air-conditioning operation of the plurality of air-conditioning units, the control of the respective refrigerant flow path switching devices and the bypass valves, the heat source side pressure reducing device, the load side pressure reducing device, and the refrigerant heat exchange are performed in accordance with signals from the control device. By controlling the opening degree of the dexterity decompression device and communicating the refrigeration cycle with the heat exchange circuit, for an air conditioning unit whose operation mode is reversed, an auxiliary heat source instead of an air heat source when performing air conditioning operation,
It can be obtained via a refrigerant heat exchanger.

That is, during the air conditioning operation, between the air conditioning units of different systems, the operation is performed while controlling the heat source side expansion valve, the load side expansion valve, and the bypass valve, so that an energy saving operation called a heat recovery operation can be performed. It is possible to suppress the peak of power consumption and contribute to leveling of power usage.

Therefore, not only can air-conditioning equipment capacity be reduced by allowing heat transfer between air-conditioning units of different systems, the cost of electric power contracted with an electric power company can also be reduced, and the amount of power consumption at high load times in the daytime can be reduced. It is possible to provide an air conditioner capable of suppressing peaks and contributing to leveling of electric power usage.

[Brief description of the drawings]

FIG. 1 is a refrigeration system diagram of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an air conditioning load transition curve with respect to time of day.

FIG. 3 is a refrigeration system diagram of an air conditioner according to a second embodiment of the present invention.

FIG. 4 is a refrigeration system diagram of an air conditioner according to a third embodiment of the present invention.

FIG. 5 is a refrigeration system diagram of a multi-room air conditioner showing a conventional example.

6A is a refrigeration system diagram of an air conditioning unit I of an air conditioner showing a conventional example. FIG. 6B is a refrigeration system diagram of an air conditioning unit II of an air conditioner showing a conventional example.

[Explanation of symbols]

 2 Compressor 3 Four-way valve 4 Outdoor heat exchanger 5 Outdoor expansion valve 7a, 7b, 7c Indoor expansion valve 8a, 8b, 8c Indoor heat exchanger I, II Air conditioning unit A, B Refrigeration cycle BV Bypass valve CN1 , CN2 controller EV expansion valve for refrigerant heat exchanger HE refrigerant heat exchanger KV switching valve

Claims (4)

(57) [Claims] 1. A refrigeration cycle comprising a compressor, a four-way valve, a heat source side heat exchanger, a heat source side pressure reducing device, a load side pressure reducing device, and a load side heat exchanger connected in a ring. An air conditioning unit, a refrigerant heat exchanger common to each of the plurality of air conditioning units, and a heat exchange circuit formed by connecting a refrigerant heat exchanger decompression device in series, via a refrigerant flow switching device, A heat exchange circuit is connected between the heat source side pressure reducing device and the load side pressure reducing device of each air conditioning unit, and a bypass is provided between the refrigerant heat exchanger and the load side heat exchanger and the four-way valve. An air conditioner comprising a control device connected by a bypass circuit provided with a valve, and a control device for setting all of the plurality of air conditioning units to the same operation mode. 2. The air conditioner according to claim 1, further comprising a control device for setting the plurality of air conditioning units to different operation modes. 3. The air conditioner according to claim 1, wherein a pulse-type electric expansion valve is provided as the pressure reducing device for the refrigerant heat exchanger, and one two-way valve is provided as the refrigerant flow switching device. 4. The air conditioner according to claim 1, wherein a temperature type expansion valve is provided as the pressure reducing device for the refrigerant heat exchanger, and a plurality of two-way valves are provided as the refrigerant flow switching device.