JPH11142018A - Air conditioning equipment and its operating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a circuit by eliminating a bypass circuit and allow a heat transfer between equipment with different loads by forming between a heat source side expansion mechanism and a load side expansion mechanism a common heat exchanger used in common by a plurality of refrigerant circuits constituted in an annular shape. SOLUTION: In a refrigerant circuit 1 used to increase a cooling capacity, a refrigerant flowing through a common heat exchanger 7 is scarcely expanded by a heat source side expansion mechanism 4a thereby to cause the refrigerant to flow to the common heat exchanger 7 in a state of high pressure liquid. Then, the refrigerant is caused to expand by a load side expansion mechanism 6a and flow to a load side heat exchanger 5a as a low pressure two phase refrigerant. In a refrigerant circuit 2 with a surplus capacity on the other hand, a refrigerant flowing through the common heat exchanger 7 is caused to expand by a heat source side expansion mechanism 4b and flow to the common heat exchanger 7 as the low pressure two phase refrigerant. Then, the refrigerant is scarcely expanded by a load side expansion mechanism 6b and flow to a load side heat exchanger 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner.

[0002]

2. Description of the Related Art FIG. 21 is an apparatus diagram of a conventional air conditioner which performs heat transfer by providing a common heat exchanger between refrigerant circuits disclosed in, for example, Japanese Patent Application Laid-Open No. 7-318186.

The circuit configuration will be described with reference to FIG.
The air conditioning units 1 and 2 include the outdoor unit 1 and the indoor units 6a, 6b, 6
refrigeration cycles A and B, which are connected to each other in an annular manner, and the heat exchanger circuit C includes a refrigerant heat exchanger H common to the refrigerant heat exchanger expansion valve EV1 and the air conditioning units 1 and 2.
E, the heat storage circuit D includes a heat storage tank expansion valve EV2 and a heat storage tank STR common to each of the air conditioning units 1 and 2, and a bypass valve BV in parallel with the indoor heat exchanger 8.
2 and a heat exchange circuit C is connected via a first two-way valve KV1 and a second two-way valve KV2, and a heat storage circuit D is connected via a third two-way valve KV3 and a fourth One-way valve KV
4, the air-conditioning units 1 and 2 are connected between the outdoor-side expansion valves 5 and the indoor-side expansion valves 7a, 7b, and 7c.

Next, the operation will be described with reference to FIG. When heat transfer between the systems from the air conditioning unit 1 to the air conditioning unit 2 is performed in daytime cooling operation, the refrigerant heat exchanger HE exits the outdoor heat exchanger 4 of the air conditioning unit 1 and then flows into the refrigerant heat exchanger HE. After leaving the high-temperature and high-pressure liquid refrigerant and the outdoor heat exchanger 4 of the air conditioning unit 2, an expansion valve EV1 for the refrigerant heat exchanger is provided.
And the second heat exchange portion 13 of the refrigerant heat exchanger HE
The heat exchange between the low-temperature and low-pressure two-phase refrigerant evaporated in the step allows heat transfer from the air conditioning unit 1 to the air conditioning unit 2 between the systems. That is, the degree of supercooling of the air conditioning unit 1 is increased by the excess cooling capacity of the air conditioning unit 2, and the cooling capacity of the indoor units 6a, 6b, 6c can be increased, and the cooling load of the air conditioning unit 1 can be handled.

When heat transfer between the systems from the air conditioning unit 1 to the air conditioning unit 2 is performed in the daytime heating operation, the refrigerant heat exchanger H
In E, after the compressor 2 is discharged from the air conditioning unit 2, the high-temperature and high-pressure gas refrigerant flowing into the refrigerant heat exchanger HE via the first bypass valve BV1 and the indoor expansion valve 7 of the air conditioning unit 1
The heat is exchanged with the low-temperature low-pressure two-phase refrigerant that has been decompressed at a, 7b, and 7c and has flowed into the refrigerant heat exchanger HE, so that heat transfer between the systems from the air conditioning unit 2 to the air conditioning unit 1 becomes possible. That is, the excess heating capacity of the air conditioning unit 2 is compensated for by the increase in the evaporation capacity of the air conditioning unit 1, that is, the heating capacity can be increased, and the heating load of the air conditioning unit 1 can be handled.

[0006]

Since the conventional air conditioner is configured as described above, a heat transfer heat exchanger common to a plurality of refrigerant circuits is connected in parallel to a liquid pipe. A bypass circuit is required, and a switching valve and an expansion mechanism are provided on the bypass circuit, and a switching valve is also provided on the main liquid pipe, which increases the cost and complicates the refrigerant piping structure and control. There is a problem that becomes.

Further, the operation purpose of each refrigerant circuit is air conditioning, and circuits having various purposes and cascade use of heat are not assumed.

In the case of defrosting the heat source side heat exchanger of the refrigerant circuit having a large load during the heating operation, the heat source side heat exchanger for which it is desired to defrost the heat of the circuit having the surplus capacity through the common heat exchanger. It is not assumed that defrosting is performed by moving to the provided circuit side.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and realizes heat transfer between devices having different loads in a plurality of air conditioners and refrigeration devices, thereby compensating for the capacity and heat efficiency. The purpose of the present invention is to obtain an air conditioner that can be used effectively.

It is another object of the present invention to provide an air conditioner in which the cost is reduced by simplifying the circuit structure and the control is simplified.

It is another object of the present invention to provide an air conditioner that enables efficient heat utilization by leveling the heat load and utilizing heat cascade.

It is another object of the present invention to provide an air conditioner capable of multipurpose use and heat cascade use, for example, assuming a low-temperature refrigeration equipment.

It is another object of the present invention to provide an air conditioner capable of performing defrosting of the heat source side heat exchanger while continuing the heating operation of the load side heat exchanger.

Another object of the present invention is to provide an air conditioner operating method capable of further increasing the cooling capacity of a certain refrigerant circuit.

Another object of the present invention is to provide an air conditioner operating method capable of further increasing the heating capacity of a certain refrigerant circuit.

It is another object of the present invention to provide a method of operating an air conditioner capable of defrosting a heat source side heat exchanger of a certain refrigerant circuit while continuing a heating operation during a heating operation.

[0017] Further, the present invention provides an air conditioner operating method capable of switching between a case where heat transfer is performed between refrigerant circuits and a case where heat transfer between the refrigerant circuits is not performed while each refrigerant circuit constantly circulates refrigerant to a common heat exchanger. It is intended to be.

[0018]

An air conditioner according to the present invention includes a compressor or a refrigerant pump, a heat source side heat exchanger, a four-way valve or a cooling / heating switching valve, a heat source side expansion mechanism, and a load side heat exchange. A plurality of refrigerant circuits configured by annularly connecting the load-side expansion mechanism and the load-side expansion mechanism, and connected between the heat-source-side expansion mechanism and the load-side expansion mechanism in a liquid pipe of the refrigerant circuit,
And a common heat exchanger shared by the refrigerant circuit.

[0019] Further, a bypass pipe for preventing refrigerant from flowing through the load-side heat exchanger and a three-way valve are provided.

Further, the common heat exchanger is provided with a liquid storage section for storing excess refrigerant.

In addition, a heat storage container provided in the common heat exchanger and filled with a medium for performing heat storage and cold storage is provided.

In at least one of the refrigerant circuits, a plurality of common heat exchangers are connected in series, and the plurality of common heat exchangers are respectively shared by a plurality of different and arbitrary other refrigerant circuits. .

Further, a cascade expansion mechanism having the same function as the heat source side expansion mechanism and the load side expansion mechanism is provided between each of the plurality of common heat exchangers.

Further, the plurality of refrigerant circuits may include an air conditioner,
This includes those used for freezing equipment, refrigeration equipment, and the like.

In the method for operating an air conditioner according to the present invention, when the cooling capacity of a certain refrigerant circuit which is performing a cooling operation among a plurality of refrigerant circuits is further increased, the refrigerant is supplied to the common refrigerant circuit at a high pressure in the certain refrigerant circuit. Circulate through the heat exchanger,
In another refrigerant circuit having a surplus capacity, the refrigerant flowing through the common heat exchanger is passed to the common heat exchanger in a low-pressure two-phase state, and the operating capacity of the compressor or the refrigerant pump is adjusted so that the common heat exchanger is operated. To control the heat transfer in the

In order to further increase the heating capacity of a certain refrigerant circuit which is performing a heating operation in a plurality of refrigerant circuits, in one refrigerant circuit, the refrigerant is passed through the common heat exchanger in a low-pressure two-phase state, and the excess In another capable refrigerant circuit, the refrigerant flowing through the common heat exchanger flows through the common heat exchanger in a high pressure state, and the operating capacity of the compressor or the refrigerant pump is adjusted to transfer heat in the common heat exchanger. Is controlled.

In the case of defrosting the heat source side heat exchanger of a refrigerant circuit that is performing a heating operation in a plurality of refrigerant circuits, the refrigerant flows through the common heat exchanger in a low-pressure two-phase state in a certain refrigerant circuit. In another refrigerant circuit having a surplus capacity, the refrigerant flowing through the common heat exchanger flows through the common heat exchanger in a high-pressure state, and the operating capacity of the compressor or the refrigerant pump is adjusted so that the common heat exchanger is operated. To control the heat transfer in the

When heat transfer is not performed between the refrigerant circuits, adjustment is made in all the refrigerant circuits, for example, to make the expansion mechanisms connected to both ends of the common heat exchanger substantially the same in the degree of restriction. When heat transfer is performed between the refrigerant circuits, for example, the expansion mechanism connected to both ends of the common heat exchanger of the refrigerant circuit whose capacity is increased by the heat transfer is set to the same degree as the other refrigerant circuits having the surplus capacity. Adjusting the throttle degree of the expansion mechanism connected to both ends of the heat exchanger to be different from the throttle degree of the expansion mechanism of another refrigerant circuit having surplus capacity,
It may involve adjusting the operating capacity of the compressor or the refrigerant pump.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of an embodiment of the present invention, and is a refrigerant circuit diagram. In the figure, A and B are heat source side units, X and Y are load side units, U is a heat transfer unit, 1a and 1b are compressors and pressurizing pumps, 2a and 2b are four-way valves and cooling / heating switching valves, 3a and 3b. Is a heat source side heat exchanger, 4a and 4b are heat source side expansion mechanisms, 5a and 5b are load side heat exchangers, 6a and 6b are load side expansion mechanisms, 7 is a common heat exchanger, and 7a and 7b are common heat exchangers. Passes 10a, 10b are discharge pipes, 11a, 1
1b is a heat source side gas pipe, 12a and 12b are load side gas pipes, 13a and 13b are heat source side liquid pipes, 14a and 14b are load side liquid pipes, and 15a and 15b are suction pipes.

In the air conditioner of the present invention, a method of increasing the cooling capacity of a certain refrigerant circuit among a plurality of refrigerant circuits sharing one common heat exchanger will be described. In this case, in a certain refrigerant circuit for increasing the cooling capacity, the refrigerant flowing through the common heat exchanger hardly expands in the heat source side expansion mechanism, becomes a high-pressure liquid state, flows through the common heat exchanger, and then expands on the load side. It is expanded by the mechanism and becomes low-pressure two-phase and flows to the load-side heat exchanger.

On the other hand, in another refrigerant circuit group having a surplus capacity, the refrigerant flowing through the common heat exchanger is expanded by the heat-source-side expansion mechanism to be in a low-pressure two-phase state, flows to the common heat exchanger, and then flows to the load side. The expansion mechanism circulates to the load side heat exchanger with little expansion, and the expansion mechanism is controlled in this manner. Further, the expansion mechanism control and the operating capacity of one or more compressors and refrigerant pumps are performed. The adjustment transfers heat from the high pressure liquid side of one circuit to the low pressure two-phase side of another circuit group to increase the degree of supercooling of the high pressure liquid in one circuit, thereby increasing the cooling capacity.

Next, the operation for increasing the cooling capacity of a certain refrigerant circuit during the cooling operation will be described with reference to the refrigerant circuit diagram of FIG. It is assumed that the refrigerant circuit 1 further increases the cooling capacity such as a high required operation load, and the refrigerant circuit 2 has a surplus capacity such as a low required operation load. During this operation,
The heat source-side heat exchangers 3a and 3b operate as condensers, and the load-side heat exchangers 5a and 5b operate as evaporators.
b is controlled as a cooling mode. Heat source side expansion mechanism 4a
Is set so that the refrigerant hardly expands, and the heat source side expansion mechanism 4b is adjusted so that the outlet supercooling temperature of the heat source side heat exchanger 3b or the outlet superheat temperature of the load side heat exchanger 5b becomes a target value. The side expansion mechanism 6a is a heat source side heat exchanger 3
a of the load side heat exchanger 5a or the outlet superheat temperature of the load side heat exchanger 5a to a target value.
b is adjusted so that the refrigerant hardly expands.

Next, the flow of the refrigerant will be described with reference to FIG. In the refrigerant circuit 1, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 a is supplied to the discharge pipe 10 a and the four-way valve 2.
a, heat source side heat exchanger 3a through heat source side gas pipe 11a
, Where it exchanges heat with the surrounding air on the heat source side to be cooled and liquefied. The liquefied refrigerant passes through the heat source side liquid pipe 13a
Flows through the heat source side expansion mechanism 4a through the common heat exchanger 7 while being hardly depressurized and kept in a high-pressure liquid state.
And heat exchange with the low-temperature low-pressure refrigerant in the refrigerant circuit 2 side, and the high-pressure liquid temperature decreases. Thereafter, the pressure is reduced by the load-side expansion mechanism 6a and flows into the load-side heat exchanger 5a via the load-side liquid pipe 14a, where the heat is exchanged with the load-side ambient air to be heated and gasified. The gasified refrigerant returns to the compressor 1a via the load-side gas pipe 12a, the four-way valve 2a, and the suction pipe 15a.

On the other hand, in the refrigerant circuit 2, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1b is supplied to the discharge pipe 10b,
The heat flows into the heat source side heat exchanger 3b via the four-way valve 2b and the heat source side gas pipe 11b, where the heat is exchanged with the surrounding air on the heat source side to be cooled and liquefied. The liquefied refrigerant is reduced in pressure by the heat source side expansion mechanism 4b via the heat source side liquid pipe 13b and flows into the common heat exchanger 7 on the way. Here, heat exchange is performed with the high-pressure liquid refrigerant on the refrigerant circuit 1 side, and the gas is heated and partially gasified. Thereafter, the refrigerant flows through the load-side expansion mechanism 6b. Here, the load-side heat exchanger 5 is hardly depressurized through the load-side liquid pipe 14b.
b, where it is gasified by heat exchange with the ambient air on the load side. The gasified refrigerant returns to the compressor 1b via the load-side gas pipe 12b, the four-way valve 2b, and the suction pipe 15b.

In the air conditioner of the present invention, a method of increasing the heating capacity of a certain refrigerant circuit among a plurality of refrigerant circuits sharing one common heat exchanger will be described. In this case, in a certain refrigerant circuit that increases the heating capacity, the refrigerant flowing through the common heat exchanger is expanded by the load-side expansion mechanism and decompressed to a low-pressure two-phase state, and flows through the common heat exchanger.
Here, heat exchange is performed with a high-pressure refrigerant flowing through another circuit, and the refrigerant is evaporated and gasified. Thereafter, the heat-source-side expansion mechanism hardly expands and flows to the heat-source-side heat exchanger, where the state of the low-pressure refrigerant adjusts the evaporating action in the heat-source-side heat exchanger.

On the other hand, in another refrigerant circuit group having a surplus capacity, the refrigerant flowing through the common heat exchanger is hardly expanded by the load-side expansion mechanism, and the high-pressure gas and the high-pressure gas depending on the load condition.
It is in a phase or liquid state and flows to the common heat exchanger, where it exchanges heat with the low-pressure two-phase refrigerant flowing in the refrigerant circuit described above, and is condensed into a high-pressure liquid. Then, it is expanded by the heat source side expansion mechanism, decompressed, and flows to the heat source side heat exchanger.

Further, by controlling the expansion mechanism and adjusting the operating capacity of one or more compressors and refrigerant pumps, heat is transferred from the high-pressure refrigerant side of the other circuit group to the low-pressure two-phase side of a certain circuit. By increasing the low pressure of the existing circuit, increasing the compressor suction density and improving the compressor operation efficiency, the heating capacity is increased by increasing the refrigerant circulation amount.

Next, the operation for increasing the heating capacity of a certain refrigerant circuit during the heating operation will be described with reference to FIG.
It is assumed that the refrigerant circuit 1 further increases the heating capacity such as a high required operation load, and the refrigerant circuit 2 has a surplus capacity such as a low required operation load. During this operation, the heat source side heat exchangers 3a and 3b serve as evaporators and serve as load side heat exchangers 5a and 5b.
b operates as a condenser, the four-way valves 2a and 2b are controlled in a heating mode, the heat-source-side expansion mechanism 4a hardly expands the refrigerant, and the heat-source-side expansion mechanism 4b heats the outlet of the heat-source-side heat exchanger 3b. The temperature or the supercooling temperature at the outlet of the load side heat exchanger 5b is adjusted to a target value,
The load-side expansion mechanism 6a sets the superheat temperature at the outlet of the heat source-side heat exchanger 3a or the supercool temperature at the outlet of the load-side heat exchanger 5a to a target value, and the load-side expansion mechanism 6b hardly expands the refrigerant. It is adjusted to.

Next, the flow of the refrigerant will be described with reference to FIG. In the refrigerant circuit 1, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 a is supplied to the discharge pipe 10 a and the four-way valve 2.
a, load side heat exchanger 3a via load side gas pipe 12a
Where it is cooled and liquefied by heat exchange with ambient air on the load side. The liquefied refrigerant passes through the load side liquid pipe 14a
The pressure is reduced by the load-side expansion mechanism 6a via the load-side expansion mechanism 6a and flows into the common heat exchanger 7, where the heat is exchanged with the high-temperature and high-pressure refrigerant on the refrigerant circuit 2 side, heated and partially evaporated. After that, the heat source side expansion pipe 4a hardly depressurizes the heat source side liquid piping 13
The gas flows into the heat source-side heat exchanger 3a via a, where the heat is exchanged with the surrounding air on the heat source side to be heated and gasified. The gasified refrigerant returns to the compressor 1a via the heat source side gas pipe 11a, the four-way valve 2a, and the suction pipe 15a.

When a large amount of heat is exchanged with the high-temperature and high-pressure refrigerant on the refrigerant circuit 2 side in the common heat exchanger 7 and evaporates into a superheated gas, the heat-source-side expansion mechanism 4a then substantially reduces the pressure. Instead, the gas flows into the heat source side heat exchanger 3a via the heat source side liquid pipe 13a, but after stopping the fan of 3a so as not to exchange heat with the surrounding air on the heat source side as much as possible, the heat source side gas pipe 11a, four-way valve 2
a, control is performed to return to the compressor 1a via the suction pipe 15a.

On the other hand, in the refrigerant circuit 2, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1b is supplied to the discharge pipe 10b,
After flowing into the load side heat exchanger 5b through the four-way valve 2b and the load side gas pipe 12b, the heat is exchanged with the load side ambient air and cooled, and then the load side expansion is performed through the load side liquid pipe 14b. Although flowing through the mechanism 6b, it flows into the common heat exchanger 7 with almost no pressure reduction. Here, heat exchange is performed with the low-pressure refrigerant on the refrigerant circuit 1 side, and the refrigerant is cooled to become a high-pressure liquid.

Thereafter, the pressure is reduced by the heat-source-side expansion mechanism 4b and flows into the heat-source-side heat exchanger 3b via the heat-source-side liquid pipe 13b, where the heat is exchanged with the surrounding air on the heat source-side and gasified. The gasified refrigerant is supplied to the heat source side gas pipe 11b and the four-way valve 2
b, return to the compressor 1b via the suction pipe 15b.

Next, in the air conditioner of the present invention, 1
A method for defrosting a heat source side heat exchanger of a certain refrigerant circuit among the plurality of refrigerant circuits sharing one common heat exchanger while the heating operation is continued will be described. In this case, in a certain circuit including a heat source side heat exchanger for defrosting, the refrigerant flowing through the common heat exchanger is expanded by the load side expansion mechanism to be in a low-pressure two-phase state and flows to the common heat exchanger, and thereafter, It flows to the heat source side heat exchanger without being expanded by the heat source side expansion mechanism.

On the other hand, in another circuit group having a surplus capacity, the refrigerant flowing through the common heat exchanger is hardly expanded by the load-side expansion mechanism and becomes a high-pressure liquid, gas and two-phase state, and flows to the common heat exchanger. Then, it is expanded by the heat-source-side expansion mechanism to become a low-pressure two-phase and flows to the heat-source-side heat exchanger.

Further, by controlling the expansion mechanism described above and adjusting the operating capacity of one or more compressors and refrigerant pumps, the high-pressure liquid, gas and two-phase By transferring the heat of the heat source, the state of the refrigerant at the outlet of the common heat exchanger of a certain circuit is converted into a low-pressure gas with a high degree of superheat, and then is circulated to the heat source side heat exchanger, where it is condensed. To defrost.

Next, an operation when a certain refrigerant circuit during the heating operation defrosts the heat source side heat exchanger while continuing the heating operation will be described with reference to FIG. It is assumed that the refrigerant circuit 1 has a heat source side heat exchanger for which defrosting is desired, and the refrigerant circuit 2 has a surplus capacity such as a low required operation load during a heating operation. The operation at the time of this operation is the same as the case where the heating capacity of a certain circuit is increased by using the surplus capacity of another circuit as described above, and a detailed description of the operation will be omitted.

Next, the flow of the refrigerant will be described with reference to FIG. In the refrigerant circuit 1, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 a is supplied to the discharge pipe 10 a and the four-way valve 2.
a, load-side heat exchanger 5a via load-side gas pipe 12a
Where it is cooled and liquefied by heat exchange with ambient air on the load side. The liquefied refrigerant passes through the load side liquid pipe 14a
The pressure is reduced by the load-side expansion mechanism 6a through the flow path and flows into the common heat exchanger 7, where the heat is exchanged with the high-temperature and high-pressure refrigerant on the refrigerant circuit 2 side.

At this time, after being heated and evaporated with a larger heat exchange amount than in the heating capacity increasing operation to become a low-pressure gas having a large degree of superheat, the heat-source-side expansion mechanism 4a hardly depressurizes the heat source-side expansion mechanism 4a. It flows into the heat source side heat exchanger 3a for which defrost is desired via the liquid pipe 13a. Here, the fan of the heat-source-side heat exchanger 3a is stopped, and the low-pressure gas refrigerant having a large degree of superheat exchanges heat with the tubes and fins of the heat-source-side heat exchanger 3a to be cooled and partially liquefied. The partially liquefied low-pressure gas refrigerant returns to the compressor 1a via the heat source side gas pipe 11a, the four-way valve 2a, and the suction pipe 15a.

On the other hand, in the refrigerant circuit 2, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1b is supplied to the discharge pipe 10b,
After flowing into the load side heat exchanger 5b through the four-way valve 2b and the load side gas pipe 12b, the heat is exchanged with the load side ambient air and cooled, and then the load side expansion is performed through the load side liquid pipe 14b. Although flowing through the mechanism 6b, it flows into the common heat exchanger 7 with almost no pressure reduction. Here, heat exchange is performed with the low-pressure refrigerant on the refrigerant circuit 1 side, and the refrigerant is cooled to become a high-pressure liquid.

Thereafter, the pressure is reduced by the heat-source-side expansion mechanism 4b and flows into the heat-source-side heat exchanger 3b through the heat-source-side liquid pipe 13b, where the heat is exchanged with the surrounding air on the heat source-side and gasified. The gasified refrigerant is supplied to the heat source side gas pipe 11b and the four-way valve 2
b, return to the compressor 1b via the suction pipe 15b.

Next, the operation when the cooling capacity of the refrigerant circuit performing the cooling operation is increased when the cooling operation and the heating operation are mixed will be described with reference to FIG. It is assumed that the refrigerant circuit 1 is performing a cooling operation and the cooling capacity is further increased, for example, the required operation load is high, and the refrigerant circuit 2 is performing a heating operation and has a surplus capacity, such as a low required operation load. During this operation, the heat source side heat exchanger 3a and the load side heat exchanger 5b operate as a condenser, the load side heat exchanger 5a and the heat source side heat exchanger 3b operate as an evaporator, the four-way valve 2a is in a cooling mode, The valve 2b is controlled in the heating mode, and the heat source side expansion mechanism 4
The load expansion mechanism 6a adjusts the outlet supercooling temperature of the heat source side heat exchanger 3a or the outlet superheat temperature of the load side heat exchanger 5a to a target value while preventing the refrigerant from expanding substantially. The load side expansion mechanism 6b is connected to the outlet superheat temperature of the heat source side heat exchanger 3b or the load side heat exchanger 5b.
Is adjusted such that the outlet subcooling temperature of the outlet becomes the target value.

Next, the flow of the refrigerant will be described with reference to FIG. In the refrigerant circuit 1, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 a is supplied to the discharge pipe 10 a and the four-way valve 2.
a, heat source side heat exchanger 3a through heat source side gas pipe 11a
, Where it exchanges heat with the surrounding air on the heat source side to be cooled and liquefied. The liquefied refrigerant passes through the heat source side liquid pipe 13a
Flows through the heat source side expansion mechanism 4a through the common heat exchanger 7 while being hardly depressurized and kept in a high-pressure liquid state.
And heat exchange with the low-temperature low-pressure refrigerant in the refrigerant circuit 2 side, and the high-pressure liquid temperature decreases.

Thereafter, the pressure is reduced by the load-side expansion mechanism 6a.
The gas flows into the load-side heat exchanger 5a via the load-side liquid pipe 14a, where it exchanges heat with the load-side ambient air and is heated and gasified. The gasified refrigerant returns to the compressor 1a via the load-side gas pipe 12a, the four-way valve 2a, and the suction pipe 15a.

On the other hand, in the refrigerant circuit 2, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1b is supplied to the discharge pipe 10b,
After flowing into the load side heat exchanger 5b through the four-way valve 2b and the load side gas pipe 12b, the heat is exchanged with the load side ambient air and cooled, and then the load side expansion is performed through the load side liquid pipe 14b. The pressure is reduced by the mechanism 6 b and flows into the common heat exchanger 7. Here, heat exchange is performed with the high-pressure liquid refrigerant on the refrigerant circuit 1 side, the gas is heated and partially gasified, and then flows through the heat source-side expansion mechanism 4b.
It flows into the heat source side heat exchanger 3b via 3b, where it exchanges heat with the surrounding air on the heat source side and gasifies. The gasified refrigerant is supplied to the heat source side gas pipe 11b, the four-way valve 2b, the suction pipe 15
Returning to the compressor 1b via b.

Next, the operation when increasing the heating capacity of the refrigerant circuit performing the heating operation when the cooling operation and the heating operation are mixed will be described with reference to FIG. It is assumed that the refrigerant circuit 1 performs the heating operation and further increases the heating capacity such as a high required operation load, and the refrigerant circuit 2 performs the cooling operation and has a surplus capacity such as a low required operation load. In this operation, the heat source side heat exchanger 3a and the load side heat exchanger 5b operate as an evaporator, the load side heat exchanger 5a and the heat source side heat exchanger 3b operate as a condenser, the four-way valve 2a is in a heating mode, and the four-way The valve 2b is controlled in the cooling mode, and the heat source side expansion mechanism 4
The load-side expansion mechanism 6a adjusts the outlet supercooling temperature of the load-side heat exchanger 5a or the outlet superheat temperature of the heat-source-side heat exchanger 3a to a target value. The load-side expansion mechanism 6b is connected to the outlet superheat temperature of the load-side heat exchanger 5b or the heat-source-side heat exchanger 3b.
Is adjusted such that the outlet subcooling temperature of the outlet becomes the target value.

Next, the flow of the refrigerant will be described with reference to FIG. In the refrigerant circuit 1, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 a is supplied to the discharge pipe 10 a and the four-way valve 2.
a, load-side heat exchanger 5a via load-side gas pipe 12a
Where it is cooled and liquefied by heat exchange with ambient air on the load side. The liquefied refrigerant passes through the load side liquid pipe 14a
The pressure is reduced by the load-side expansion mechanism 6a via the load-side expansion mechanism 6a and flows into the common heat exchanger 7, where the heat is exchanged with the high-temperature and high-pressure refrigerant on the refrigerant circuit 2 side, heated and partially evaporated.

After that, the heat-source-side expansion mechanism 4a hardly depressurizes and flows into the heat-source-side heat exchanger 3a through the heat-source-side liquid pipe 13a, where it is exchanged with the load-side ambient air for heating and gasification. I do. The gasified refrigerant returns to the compressor 1a via the heat source side gas pipe 11a, the four-way valve 2a, and the suction pipe 15a. In the common heat exchanger 7, the amount of heat generated by heat exchange with the high-temperature and high-pressure refrigerant on the refrigerant circuit 2 side is large, and the refrigerant that has evaporated to become a heated gas is hardly depressurized by the heat-source-side expansion mechanism 4a. After flowing into the heat source side heat exchanger 3a through the heat source side liquid pipe 13a, the fan of the heat source side 3a is stopped so that heat is not exchanged with the surrounding air on the heat source side as much as possible. Valve 2
a, control is made to return to the compressor 1a via the suction pipe 15a.

On the other hand, in the refrigerant circuit 2, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1b is supplied to the discharge pipe 10b,
The heat flows into the heat source side heat exchanger 3b via the four-way valve 2b and the heat source side gas pipe 11b, where the heat is exchanged with the surrounding air on the heat source side to be cooled and liquefied. The liquefied refrigerant flows through the heat-source-side expansion mechanism 4b through the heat-source-side liquid pipe 13b, but flows into the common heat exchanger 7 without being depressurized. Here, heat exchange is performed with the low-pressure refrigerant on the refrigerant circuit 1 side, and the liquid is cooled to lower the liquid temperature. Thereafter, the pressure is reduced by the load-side expansion mechanism 6b and flows into the load-side heat exchanger 5b through the load-side liquid pipe 14b, where the heat is exchanged with ambient air on the load side and gasified. The gasified refrigerant is supplied to the load-side gas pipe 12b and the four-way valve 2
b, return to the compressor 1b via the suction pipe 15b.

Next, in the air conditioner of the present invention,
Of a plurality of refrigerant circuits sharing one common heat exchanger,
An operation method when heat transfer is performed from one circuit to another circuit via a common heat exchanger and when heat transfer is not performed will be described.
In the case where heat transfer is not performed, in all circuits, for example, adjustments such as making the expansion mechanisms connected to both ends of the common heat exchanger approximately the same are performed, and each circuit flowing through the common heat exchanger is adjusted. Avoid temperature differences between refrigerants. On the other hand, for example, in the case of performing heat transfer, adjustment is performed such that the expansion degree of the expansion mechanism of the circuit that increases the capacity by the heat transfer is different from the expansion state of the expansion mechanism of another circuit group having excess capacity. The refrigerant flowing through the common heat exchanger has a temperature difference between the refrigerant of the circuit that is heat-transferred to increase the capacity and the refrigerant of another circuit group that supplies heat so as to facilitate heat transfer. Alternatively, the operating capacity of the compressor and the refrigerant pump is adjusted, and the amount of heat transfer is controlled by adjusting the flow rate of the refrigerant flowing through the common heat exchanger.

In this embodiment, as shown in FIG. 7, an oil separator 21 is provided in the middle of the discharge pipes 10a and 10b.
a, 21b, and as shown in FIG.
Even if the liquid separators 22a and 22b are installed in the middle of 5a and 15b, the basic operation and the flow of the refrigerant are the same as those without the oil separator and the liquid separator.

As described above, in the first embodiment, a single common heat exchanger having expansion mechanisms at both ends is shared by a plurality of refrigerant circuits, so that heat can be transferred between the plurality of refrigerant circuits and cooling is performed. In both the operation and the heating operation, it is possible to supplement the capacity of a refrigerant circuit having a maximum capacity shortage with respect to a required operation load from a plurality of refrigerant circuit groups having a surplus capacity.

The amount of heat transfer is adjusted by controlling the temperature difference between the high-pressure refrigerant and the low-pressure refrigerant exchanged by the common heat exchanger under the control of the heat-source-side expansion mechanism and the load-side expansion mechanism provided in each refrigerant circuit. By adjusting the compressor capacity of a plurality of refrigerant circuits that have been adjusted and have excess capacity, it is possible to provide an air conditioner that adjusts the amount of refrigerant circulating through the circuits and controls the amount of heat transferred between the refrigerant circuits. It is.

FIG. 9 shows an example in which the first embodiment is applied to a building or the like. Rooms X1, X2, Y1, and Y2 are rooms on one floor of a certain building. An indoor unit is installed in each room, and the X1 and X2 indoor units are connected to the outdoor unit A to form one refrigerant circuit, and the Y1 and Y2 indoor units are connected to the outdoor unit B to form one refrigerant circuit. I do. The respective refrigerant circuits compensate for one another via a common heat exchanger.

Embodiment 2 FIG. 10 is a diagram showing another example of the embodiment of the present invention and is a refrigerant circuit diagram. The three-way valves 8a and 8b and the load-side bypass pipes 16a and 16b are added to the refrigerant circuit of the first embodiment in FIG.

In FIG. 10, the three-way valves 8a and 8b and the load-side bypass pipes 16a and 16b do not use the entire load-side heat exchanger in one refrigerant circuit and are common to increase the capacity of the other refrigerant circuits. When heat is supplied via the heat exchanger, the bypass pipe flows instead of the refrigerant flowing through the load side heat exchanger.

In this embodiment, when the refrigerant flows through the bypass pipe, the common heat exchanger functions as a main condenser and an evaporator in the refrigerant circuit.

In this embodiment, by providing a bypass pipe and a three-way valve for preventing refrigerant from flowing through the load-side heat exchanger group, a refrigerant circuit that does not require an operation on the load side can compensate for the capacity of another refrigerant circuit. Therefore, it is possible to provide an air conditioner that eliminates the noise problem due to the circulation of the refrigerant to the stop load heat exchanger by not allowing the refrigerant to flow to the stop load heat exchanger. Incidentally, even if the fan of the stop load heat exchanger is stopped and the refrigerant is allowed to flow without using the bypass, the same effect can be obtained although there is some heat loss.

Embodiment 3 FIG. 11 is a diagram showing another example of the embodiment of the present invention, and is a refrigerant circuit diagram. A liquid storage unit for storing surplus refrigerant is provided in the common heat exchanger of the first embodiment. 23 is a liquid reservoir, and 23a and 23b are liquid reservoirs of each refrigerant circuit.

By using the liquid storage container 23, the excess refrigerant in each circuit can be stored here, so that the liquid storage container in each refrigerant circuit is removed to reduce the cost. To be provided. The heat transfer method and the flow of the refrigerant in this embodiment are the same as those in the first embodiment.
Therefore, the description is omitted.

Embodiment 4 FIG. 12 is a diagram showing another example of the embodiment of the present invention, and is a refrigerant circuit diagram. A heat storage container 24 provided in the common heat exchanger of the first embodiment and filled with a medium for performing heat storage and cold storage is added.

By adding the heat storage container 24, each circuit can generate ice using inexpensive electric power such as midnight electric power, and use this when daytime cooling operation demand is high to supplement the capacity. It is possible. At the same time, it is needless to say that the capability insufficiency circuit described in the first embodiment can be supplemented from another circuit.

The flow of the refrigerant and the basic heat transfer method in the common heat exchanger are the same as in the first embodiment. Here, an example will be described with reference to FIG. 13 in which water is used as the refrigerant storage medium, ice is generated by electric power at midnight, and cooling operation is performed using the ice in the daytime.

When both the refrigerant circuit 1 and the refrigerant circuit 2 are low in electricity cost and the cooling operation load is low, such as at night, the common heat exchanger 7 is an evaporator, the heat source side heat exchangers 3a and 3b are condensers, and the load side is a heat exchanger. The heat exchanger operates only as the evaporator using the heat exchanger requiring cooling operation, the four-way valves 2a and 2b are controlled in the cooling mode, and the heat source side expansion mechanisms 4a and 4b are connected to the outlets of the heat source side heat exchangers 3a and 3b. Subcooling temperature or load side heat exchanger 5
a, 5b or the refrigerant flowing through the common heat exchanger 7 is adjusted so as to have a target value, the load-side expansion mechanisms 6a, 6b are adjusted so as to be hardly expanded, and the operating capacity of each circuit is controlled by the heat storage container 24. Adjusted based on the amount of ice produced.

Next, the flow of the refrigerant will be described with reference to FIG. In the refrigerant circuit 1 and the refrigerant circuit 2, the compressors 1a, 1
b, the high-temperature and high-pressure gas refrigerant discharged from the discharge pipe 10
a, 10b, four-way valve 2a, 2b heat source side gas pipe 12a,
The air flows into the heat source side heat exchangers 3a and 3b via the heat source side 12b, where the heat is exchanged with the surrounding air on the heat source side to be cooled and liquefied.
The liquefied refrigerant flows through the heat source side expansion mechanisms 4a and 4b via the heat source side liquid pipes, and is decompressed and flows into the common heat exchanger 7 in a low pressure two-phase state, where it stays in the heat storage container 24. Heat exchange with the water you are making to make the water ice.

After that, the pressure is hardly reduced by the load-side expansion mechanisms 6a and 6b, and flows into the load-side heat exchangers 5a and 5b via the load-side liquid pipes 14a and 14b, where the ambient air and the heat on the load side are removed. It is exchanged, heated and gasified. The gasified low-pressure refrigerant is supplied to the compressor 1 via the load-side gas pipes 12a and 12b, the four-way valves 2a and 2b, and the suction pipes 15a and 15b.
Return to a and 1b.

On the other hand, in the daytime, the refrigerant circuit 1 and the refrigerant circuit 2
In both cases, when the cooling operation load is large, the common heat exchanger 7 passing through the heat storage container 24 in the ice state is a supercooler, the heat source side heat exchangers 3a and 3b are condensers, and the load side heat exchangers 5a and 5a.
b operates as an evaporator, the four-way valves 2a and 2b are controlled in a cooling mode, and the load-side expansion mechanisms 6a and 6b are supercooled at the outlets of the heat-source-side heat exchangers 3a and 3b or the load-side heat exchangers 5a and 5b. 5b or the temperature of the refrigerant flowing through the common heat exchanger 7 is adjusted to the target value, and the heat source side expansion mechanism 4a,
4b is adjusted so that it hardly expands, and the operating capacity of each circuit is adjusted based on the capacity required by the load side.

As described above, in the fourth embodiment, by adding a heat storage container to the circuit of the first embodiment, ice is generated using, for example, midnight electric power, and the cooling capacity is increased when daytime cooling demand is high. The present invention makes it possible to provide an air conditioner that realizes capacity filling when capacity is insufficient by heat storage and cold storage, such as preventing capacity shortage by compensating for power and reducing electricity costs for operation.

FIG. 14 shows an example in which the fourth embodiment is applied to a building or the like. Rooms X1, X2, Y1, and Y2 are rooms on one floor of a certain building. An indoor unit is installed in each room, and the X1 and X2 indoor units are connected to the outdoor unit A to form one refrigerant circuit, and the Y1 and Y2 indoor units are connected to the outdoor unit B to form one refrigerant circuit. I do. Each refrigerant circuit creates ice in the heat storage container using inexpensive electricity such as midnight power, and performs cooling operation using ice in the daytime,
An operation is also performed through a common heat exchanger to compensate for the shortage of each other.

Embodiment 5 FIG. FIG. 15 is a refrigerant circuit diagram showing another example of the embodiment of the present invention. The common heat exchanger 7 of the refrigerant circuit of the first embodiment is divided into 7-1 and 7-2, each of which is shared with a separate circuit.

Since the heat transfer method and the flow of the refrigerant in this embodiment are the same as those in the first embodiment, the description will be omitted.

In this embodiment, one refrigerant circuit includes a plurality of common heat exchangers, and each common heat exchanger performs heat transfer with a separate refrigerant circuit, so that heat transfer is performed via the plurality of refrigerant circuits. Therefore, it is possible to provide an air conditioner capable of efficiently using heat of the entire system by utilizing heat cascade.

Embodiment 6 FIG. FIG. 16 is a diagram showing another example of the embodiment of the present invention, and is a refrigerant circuit diagram. The cascade expansion mechanism 9c is provided between the common heat exchangers of the refrigerant circuit of the fifth embodiment.

Next, an example of operation when a circuit having a plurality of common heat exchangers connecting expansion mechanisms at both ends increases the heating capacity of another low-temperature refrigeration circuit and an air-conditioning circuit will be described with reference to FIG. Will be explained. The refrigerant circuit 1 requires an increase in cooling capacity in a low-temperature refrigeration circuit, the refrigerant circuit 2 requires an increase in heating capacity in an air-conditioning circuit, and the refrigerant circuit 3 performs heating operation on the load side. Assume a case where the increase in capacity of 2 is compensated.

In the refrigerant circuit 1, the heat source side heat exchanger 3a operates as a condenser, and the load side heat exchanger 5a operates as an evaporator.
The four-way valve 2a is controlled in a cooling mode, the heat-source-side expansion mechanism 4a hardly expands the refrigerant, and the load-side expansion mechanism 6a operates at the outlet subcooling temperature of the heat-source-side heat exchanger 3a or the load-side heat exchanger 5a. Is expanded and adjusted so that the outlet superheat temperature becomes the target value.

In the refrigerant circuit 2, the heat source side heat exchanger 3b operates as an evaporator, the load side heat exchanger 5b operates as a condenser, the four-way valve 2b is controlled in a heating mode, and the load side expansion mechanism 6b controls the refrigerant. It is expanded and adjusted so that the outlet supercooling temperature of the load side heat exchanger 5b or the outlet superheat temperature of the heat source side heat exchanger 3b becomes a target value, and the heat source side expansion mechanism 4b hardly expands. It is adjusted to.

In the refrigerant circuit 3, the load side heat exchanger 5c operates as a condenser and the heat source side heat exchanger 3c operates as an evaporator.
When the four-way valve 2c is set to the heating mode, the heat source side expansion mechanism 4
c and the load-side expansion mechanism 6c hardly expand the refrigerant, and the cascade expansion mechanism 9c has a target value of the supercooling temperature at the outlet of the load-side heat exchanger 5c or the superheat temperature at the outlet of the heat-source-side heat exchanger 3c. Is adjusted as follows.

Next, the flow of the refrigerant will be described with reference to FIG. In the refrigerant circuit 1, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 a is supplied to the discharge pipe 10 a and the four-way valve 2.
a, heat source side heat exchanger 3a through heat source side gas pipe 11a
Flows through the heat-source-side expansion mechanism 4a through the heat-source-side liquid pipe in a high-pressure gas or two-phase state with little heat exchange in order to stop the heat exchanger fan. Flows into the common heat exchanger 7-1 in a high-pressure gas or two-phase state. Here, the refrigerant exchanges heat with the low-pressure two-phase refrigerant flowing through the common heat exchanger 7-1 on the refrigerant circuit 3 side, condenses, and becomes a high-pressure liquid.

Thereafter, the pressure is reduced by the load-side expansion mechanism 6a.
The gas flows into the load-side heat exchanger 5a via the load-side liquid pipe 14a, where it exchanges heat with the load-side ambient air and is heated and gasified. The gasified refrigerant returns to the compressor 1a via the load-side gas pipe 12a, the four-way valve 2a, and the suction pipe 15a.

On the other hand, in the refrigerant circuit 2, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1b is supplied to the discharge pipe 10b,
The gas flows into the load-side heat exchanger 3b via the four-way valve 2b and the load-side gas pipe 12b, where it exchanges heat with the load-side ambient air to be cooled and liquefied. The liquefied refrigerant is reduced in pressure by the load-side expansion mechanism 6b via the load-side liquid pipe 14b, enters a low-pressure two-phase state, and flows into the common heat exchanger 7-2. Here, heat exchange is performed with the high-pressure liquid refrigerant flowing through the common heat exchanger 7-2 of the refrigerant circuit 3 to evaporate and partially gasify.

After that, the gas flows through the heat source side expansion mechanism 4b.
Here, the pressure is hardly reduced and flows into the heat source side heat exchanger 3b via the load side liquid pipe 13b. Here, the air flow is adjusted according to the state of the low-pressure refrigerant to control the evaporating action and gasify the gas. The gasified low-pressure refrigerant is supplied to the heat source side gas pipe 11.
b, return to the compressor 1b via the four-way valve 2b and the suction pipe 15b.

On the other hand, in the refrigerant circuit 3, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1c is discharged from the discharge pipe 10c.
After flowing into the load-side heat exchanger 5c through the four-way valve 2c and the load-side gas pipe 12c, the heat is exchanged with the load-side ambient air and cooled, and then the load-side expansion is performed through the load-side liquid pipe 14c. Although flowing through the mechanism 6c, the pressure is hardly reduced here and flows into the common heat exchanger 7-2 in a high-pressure two-phase state. Here, heat exchange is performed with the low-pressure two-phase refrigerant on the refrigerant circuit 2 side, and the refrigerant is cooled to become a high-pressure liquid.

Thereafter, the pressure is reduced by the cascade expansion mechanism 9c to be in a low-pressure two-phase state, and flows into the common heat exchanger 7-1. Here, heat exchange is performed with the high-pressure liquid refrigerant on the refrigerant circuit 2 side,
Partially gasifies. After that, it flows to the heat source-side expansion mechanism 4c, but is hardly depressurized here.
The gas flows into the heat source side heat exchanger 3c through the heat exchanger c, where the heat is exchanged with the surrounding air on the heat source side and gasified. The gasified refrigerant is supplied to the heat source side gas pipe 11c, the four-way valve 2c, and the suction pipe 15c.
And returns to the compressor 1c.

The refrigerant circuit having a small load and including a plurality of common heat exchangers can supplement the cooling operation and the heating operation of other circuits.

Similarly, a circuit having a plurality of common heat exchangers can increase the cooling capacity of other low-temperature refrigeration circuits and air-conditioning circuits. Hereinafter, description will be made with reference to FIG.

The refrigerant circuit 1 requires an increase in cooling capacity in a low-temperature refrigeration circuit, the refrigerant circuit 2 requires an increase in cooling capacity in an air-conditioning circuit, and the refrigerant circuit 3 performs heating operation on the load side. It is assumed that the increase in the capacity of the refrigerant circuits 1 and 2 is compensated for. Detailed description of the cooling and heating operation is omitted, and only the points will be described here. In the refrigerant circuit 1, the heat source side expansion mechanism 4a hardly expands the refrigerant,
The load-side expansion mechanism 6a is adjusted so that the outlet supercooling temperature of the heat source-side heat exchanger 3a or the outlet superheat temperature of the load-side heat exchanger 5a becomes a target value. When the heat exchange amount is minimized, the refrigerant flowing through the common heat exchanger 7-1 becomes a high-pressure gas or a two-phase state, and the heat exchange amount with the outside air in the heat source side heat exchanger 3a is large. In this case, the refrigerant flowing through the common heat exchanger 7-1 is adjusted to be in a high-pressure two-phase or liquid state.

The common heat exchanger 7-1 exchanges heat with the low-pressure two-phase refrigerant flowing through the common heat exchanger 7-1 of the refrigerant circuit 3, and
The refrigerant flowing through the common heat exchanger 7-1 of the refrigerant circuit 1 is cooled and liquefied. On the other hand, since the temperature of the refrigerant flowing through the common heat exchanger 7-1 of the refrigerant circuit 3 is low, the condensation temperature of the refrigerant circuit 1 is low, and as a result, a low-temperature evaporation temperature can be generated, and the refrigerant corresponding to the refrigeration equipment Circuits can be added to a group of circuits.

In the refrigerant circuit 2, the heat source side expansion mechanism 4b hardly expands the refrigerant, and
b is adjusted so that the outlet supercooling temperature of the heat source side heat exchanger 3b or the outlet superheat temperature of the load side heat exchanger 5b becomes a target value. The refrigerant flowing through the common heat exchanger 7-2 is in a high-pressure liquid state, and exchanges heat with the low-pressure two-phase refrigerant flowing through the common heat exchanger 7-2 of the refrigerant circuit 3 to increase the degree of supercooling, thereby cooling. Ability increases.

In the refrigerant circuit 3, the heat source side expansion mechanism 4c and in the cascade expansion mechanism 9c, the refrigerant is hardly expanded, and the load side expansion mechanism 6c is connected to the load side heat exchanger 5c.
And the superheat temperature at the outlet of the heat source side heat exchanger 3c is adjusted to the target value.
The refrigerant flowing through the paths 7ca and 7cb in the -1 and 7-2 is adjusted so as to be in a low-pressure two-phase state, and a high-pressure gas, a two-phase or liquid refrigerant in the refrigerant circuit 1, and a high-pressure liquid refrigerant in the refrigerant circuit 2, respectively. Heat is exchanged with the gas and it is heated and turned into gas. The description of the flow of the refrigerant is omitted.

In this embodiment, in a circuit having a plurality of common heat exchangers having expansion mechanisms connected to both ends, the pressure inside the common heat exchanger located at the most upstream side of the refrigerant flow is the highest and the most downstream side is located at the most downstream side. , The internal pressure of the common heat exchanger is lowest, and the internal pressures of the plurality of common heat exchangers located therebetween indicate values gradually decreasing in the order of flow. A high-pressure common heat exchanger supplies heat to other refrigerant circuits, thereby increasing the heating capacity of the other refrigerant circuits mainly, or increasing the cooling capacity of the main circuit, etc. In a low-pressure common heat exchanger, heat is recovered from other refrigerant circuits to compensate for the evaporation capacity of this circuit, mainly to increase the heating capacity, or to recover heat mainly from other refrigerant circuits. The cooling capacity can be increased, etc., and each common heat exchanger performs heat transfer between different refrigerant circuits according to the purpose and desired load, so that the efficiency by heat cascade use And load leveling of the entire system can be achieved.

For example, FIG. 19 shows an example in which the present system is installed in a store provided with refrigeration equipment. Air conditioners 1, 2, and 3 are installed in room X, and air conditioners 4 and 5 are installed in room Y.
In the X room, showcases 6 for storing frozen foods, etc.
7, 8 are installed. Indoor units 1, 2, and 3 are outdoor units A
The indoor units 4 and 5 are connected to the outdoor unit B, and the showcases 6, 7, and
Numerals 8 are connected to the outdoor unit C to form respective refrigerant circuits. Each circuit has a common heat exchanger, and the capacity of other circuits is supplemented through the common heat exchanger.

Embodiment 7 FIG. FIG. 20 is a diagram showing another example of the embodiment of the present invention and is a refrigerant circuit diagram. In the refrigerant circuit of the first embodiment, for example, a common heat exchange surrounded by a heat storage container 24 in parallel with a common heat exchanger 7-1a provided between the heat source-side expansion mechanism 3a and the load-side heat exchanger 5a. 7-1b.

In this case, a more efficient operation can be achieved by using a common heat exchanger to be used depending on whether the ice generated in the heat storage container 24 is used or when the capacity is supplemented in each circuit. Become. The operation method and the flow of the refrigerant are omitted because they are the same as those already described in the other embodiments.

[0103]

The air conditioner according to the present invention includes a compressor or a refrigerant pump, a heat source side heat exchanger, a four-way valve or a cooling / heating switching valve, a heat source side expansion mechanism, a load side heat exchanger,
A plurality of refrigerant circuits configured by annularly connecting the load-side expansion mechanism, and a common pipe connected between the heat-source-side expansion mechanism and the load-side expansion mechanism in a liquid pipe of the refrigerant circuit and shared by the refrigerant circuit. With a configuration including a heat exchanger, the circuit and control can be simplified without installing a bypass circuit having a switching valve and an expansion mechanism for the common heat exchanger, and the surplus capacity between a plurality of refrigerant circuits can be achieved. The required heat is transferred from a certain circuit to the under-capacity circuit via a common heat exchanger, and the capacity of the under-capacity circuit can be compensated. Enables efficient use of heat throughout.

Further, since a bypass pipe for preventing refrigerant from flowing through the load-side heat exchanger and a three-way valve are provided, the problem of noise caused by refrigerant flowing to the stopped load heat exchanger is eliminated.

Further, since the common heat exchanger is provided with a liquid storage section for storing the surplus refrigerant, the liquid storage containers in each refrigerant circuit are removed, thereby enabling cost reduction.

Further, since the common heat exchanger is provided with a heat storage container filled with a medium for performing heat storage and cold storage, each circuit can store and store heat using inexpensive electric power such as late-night electric power. It can be used to supplement capacity when heating / cooling operation demand is high.

Further, in at least one refrigerant circuit, a plurality of common heat exchangers are connected in series, and each of the plurality of common heat exchangers is shared by a separate and arbitrary plurality of other refrigerant circuits. Since the common heat exchanger performs heat transfer with separate refrigerant circuits, heat transfer can be performed across multiple refrigerant circuits, enabling efficient use of heat of the entire system by using heat cascade. An air conditioner can be provided. .

Further, the cascade expansion mechanism is arranged between the common heat exchangers so that the expansion mechanisms are connected to both ends of the plurality of common heat exchangers. The exchanger performs heat transfer between a plurality of separate refrigerant circuits according to the purpose and the desired load amount, so that efficiency can be improved by using heat cascade, and load leveling as a whole system can be achieved. Become. .

Further, the plurality of refrigerant circuits include an air conditioner,
Because it is configured to include those used for refrigeration equipment, refrigeration equipment, etc., each refrigerant circuit sharing a common heat exchanger transfers heat between multiple circuits with different purposes such as air conditioning and refrigeration. It is also possible.

[0110] The method of operating an air conditioner according to the present invention is characterized in that, when the cooling capacity of a certain refrigerant circuit that is performing a cooling operation among a plurality of refrigerant circuits is further increased, the refrigerant in the certain refrigerant circuit is subjected to the common pressure in a high pressure state. Circulate through the heat exchanger,
In another refrigerant circuit having a surplus capacity, the refrigerant flowing through the common heat exchanger is passed to the common heat exchanger in a low-pressure two-phase state, and the operating capacity of the compressor or the refrigerant pump is adjusted so that the common heat exchanger is operated. By controlling the heat transfer in the refrigerant circuit, the cooling capacity of a certain refrigerant circuit can be further increased.

When the heating capacity of a certain refrigerant circuit in a heating operation among a plurality of refrigerant circuits is to be further increased, in a certain refrigerant circuit, the refrigerant is passed through the common heat exchanger in a low-pressure two-phase state, so In another capable refrigerant circuit, the refrigerant flowing through the common heat exchanger flows through the common heat exchanger in a high pressure state, and the operating capacity of the compressor or the refrigerant pump is adjusted to transfer heat in the common heat exchanger. , The heating capacity of a certain refrigerant circuit can be further increased.

In the case of defrosting the heat source-side heat exchanger of a refrigerant circuit that continues to perform a heating operation during a heating operation in a plurality of refrigerant circuits, in one of the refrigerant circuits, the refrigerant is discharged in a low-pressure two-phase state. In another refrigerant circuit having a surplus capacity, the refrigerant flowing through the common heat exchanger is circulated through the common heat exchanger in a high pressure state to adjust the operating capacity of the compressor or the refrigerant pump. Then, by controlling the heat transfer in the common heat exchanger, it is possible to defrost the heat source side heat exchanger of a certain refrigerant circuit that is performing the heating operation.

In the case where heat transfer is not performed between the refrigerant circuits, for example, in all of the refrigerant circuits, adjustments such as making the expansion mechanisms connected to both ends of the common heat exchanger approximately the same degree of throttle are performed. In order to eliminate the temperature difference between the refrigerant flowing through the common heat exchanger and perform heat transfer between the refrigerant circuits, for example, connect to both ends of the common heat exchanger of the refrigerant circuit whose capacity is increased by heat transfer. The throttling degree of the expansion mechanism is adjusted to be different from the throttling degree of the expansion mechanism connected to both ends of the common heat exchanger of the other refrigerant circuit having the surplus capacity, and the inside of the common heat exchanger is adjusted. The heat transfer is performed by securing the temperature difference between the flowing refrigerants, and the heat transfer amount between the refrigerant circuits can be adjusted by adjusting the operating capacity of the compressor or the refrigerant pump.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram showing Embodiment 1 of the present invention.

FIG. 2 is a refrigerant circuit diagram illustrating a flow of a refrigerant when a cooling capacity of one circuit of the first embodiment is increased.

FIG. 3 is a refrigerant circuit diagram illustrating a flow of a refrigerant when a heating capacity of one circuit of the first embodiment is increased.

FIG. 4 is a refrigerant circuit diagram showing the flow of refrigerant when defrosting the heat source side heat exchanger while continuing the heating operation of one circuit of the first embodiment.

FIG. 5 is a refrigerant circuit diagram showing the flow of refrigerant when the cooling capacity of one circuit is increased when cooling and heating operations are mixed in the first embodiment.

FIG. 6 is a refrigerant circuit diagram showing the flow of refrigerant when the heating capacity of one circuit increases when cooling and heating operations are mixed in the first embodiment.

FIG. 7 is a refrigerant circuit diagram when an oil separator is installed in the refrigerant circuit diagram of the first embodiment.

FIG. 8 is a refrigerant circuit diagram when a liquid separator is installed in the refrigerant circuit diagram of the first embodiment.

FIG. 9 is a diagram illustrating an example of a case where the refrigerant circuit according to the first embodiment is installed in a building or the like;

FIG. 10 is a refrigerant circuit diagram showing Embodiment 2 of the present invention.

FIG. 11 is a refrigerant circuit diagram showing Embodiment 3 of the present invention.

FIG. 12 is a refrigerant circuit diagram showing Embodiment 4 of the present invention.

FIG. 13 is a refrigerant circuit diagram showing a flow of a refrigerant when each refrigerant circuit of the fourth embodiment uses a common heat exchanger to generate ice in a heat storage container.

FIG. 14 is a diagram illustrating an example of a case where the refrigerant circuit according to Embodiment 4 is installed in a building or the like.

FIG. 15 is a refrigerant circuit diagram showing Embodiment 5 of the present invention.

FIG. 16 is a refrigerant circuit diagram showing Embodiment 6 of the present invention.

FIG. 17 is a refrigerant circuit diagram illustrating the flow of refrigerant during the heating operation of the air-conditioning apparatus according to Embodiment 6 and when the capacity of the refrigeration equipment is increased.

FIG. 18 is a refrigerant circuit diagram showing the flow of refrigerant when the air conditioner according to Embodiment 6 performs the cooling operation and the capacity of the refrigeration equipment increases.

FIG. 19 is a diagram illustrating an example of a case where the refrigerant circuit according to Embodiment 6 is installed in a store or the like.

FIG. 20 is a refrigerant circuit diagram showing Embodiment 7 of the present invention.

FIG. 21 is a refrigerant circuit diagram of a conventional air conditioner.

[Explanation of symbols]

A, B Heat source side unit, X, Y Load side unit, U
Heat transfer unit, 1a, 1b, 1c Compressor and pressurizing pump, 2a, 2b, 2c Four-way valve and cooling / heating switching valve, 3
a, 3b, 3c Heat source side heat exchanger, 4a, 4b, 4c
Heat source side expansion mechanism, 5a, 5b, 5c load side heat exchanger,
6a, 6b, 6c Load side expansion mechanism, 7, 7-1, 7-
2,7-1a, 7-1b common heat exchanger, 7a, 7b,
7ca, 7cb Common heat exchanger path, 8a, 8b Three-way valve, 9c Cascade expansion mechanism, 10a, 10b, 1
0c Discharge pipe, 11a, 11b, 11c Heat source side gas pipe, 12a, 12b, 12c Load side gas pipe, 13
a, 13b, 13c Heat source side liquid piping, 14a, 14b,
14c Load side liquid pipe, 15a, 115b, 15c suction pipe, 16a, 16b Load side bypass pipe, 21a, 2
1b oil separator, 22a, 22b liquid separator, 23 liquid storage container, 24 heat storage container.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Fumio Matsuoka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Within Mitsui Electric Co., Ltd. (72) Toshiaki Yoshikawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Kunihiro Inui 2-6-1, Otemachi, Chiyoda-ku, Tokyo Mitsui Electric Engineering Co., Ltd.

Claims (11)

[Claims] 1. A compressor or a refrigerant pump, a heat-source-side heat exchanger, a four-way valve or a cooling / heating switching valve, a heat-source-side expansion mechanism, a load-side heat exchanger, and a load-side expansion mechanism connected in a ring. And a common heat exchanger connected between the heat source side expansion mechanism and the load side expansion mechanism in a liquid pipe of the refrigerant circuit and shared by the refrigerant circuit. An air conditioner, characterized in that: 2. The air conditioner according to claim 1, further comprising a bypass pipe for preventing a refrigerant from flowing through the load-side heat exchanger, and a three-way valve. 3. The air conditioner according to claim 1, wherein the common heat exchanger is provided with a liquid storage section for storing excess refrigerant. 4. The air conditioner according to claim 1, further comprising a heat storage container provided in the common heat exchanger and filled with a medium for performing heat storage and cold storage. 5. In at least one of the refrigerant circuits, a plurality of the common heat exchangers are connected in series, and each of the plurality of common heat exchangers is separated and shared by an arbitrary plurality of other refrigerant circuits. The air conditioner according to claim 1, wherein: 6. A cascade expansion mechanism having the same function as the heat-source-side expansion mechanism and the load-side expansion mechanism is provided between each of the plurality of common heat exchangers. 6. The air conditioner according to 5. 7. The air conditioner, wherein the plurality of refrigerant circuits include:
The air conditioner according to claim 1, wherein the air conditioner includes a device used for a freezing device, a refrigeration device, and the like. 8. The method for operating an air conditioner according to claim 1, wherein the cooling capacity of one of the plurality of refrigerant circuits that is performing a cooling operation is further increased. In this case, in the certain refrigerant circuit, the refrigerant flows through the common heat exchanger in a high pressure state, and in the other refrigerant circuit having surplus capacity, the refrigerant flowing through the common heat exchanger is in a low pressure two-phase state. A method of operating an air conditioner, comprising: circulating the heat to the common heat exchanger; and adjusting the operating capacity of the compressor or the refrigerant pump to control heat transfer in the common heat exchanger. 9. The method for operating an air conditioner according to claim 1, wherein the heating capacity of a refrigerant circuit that is performing a heating operation in the plurality of refrigerant circuits is further increased. In this case, in the certain refrigerant circuit, the refrigerant flows through the common heat exchanger in a low-pressure two-phase state, and in another refrigerant circuit having a surplus capacity, the refrigerant flowing through the common heat exchanger is in a high-pressure state. A method of operating an air conditioner, comprising: circulating the heat to the common heat exchanger; and adjusting the operating capacity of the compressor or the refrigerant pump to control heat transfer in the common heat exchanger. 10. The method for operating an air-conditioning apparatus according to claim 1, 5 or 6, wherein the heat source side heat exchanger of a refrigerant circuit that is performing a heating operation in the plurality of refrigerant circuits. When defrosting, in the certain refrigerant circuit, the refrigerant flows in the common heat exchanger in a low-pressure two-phase state, and in the other refrigerant circuit having excess capacity, the refrigerant flowing in the common heat exchanger is Circulating the high-pressure state to the common heat exchanger, and adjusting the operating capacity of the compressor or the refrigerant pump to control heat transfer in the common heat exchanger. 11. The method for operating an air conditioner according to claim 1, wherein the heat transfer is not performed between the refrigerant circuits. If the expansion mechanism connected to both ends of the common heat exchanger is adjusted such that the degree of throttle is substantially the same, and heat is transferred between the refrigerant circuits, for example, the capacity is increased by heat transfer. The degree of restriction of the expansion mechanism connected to both ends of the common heat exchanger of the refrigerant circuit is the degree of restriction of the expansion mechanism connected to both ends of the common heat exchanger of the other refrigerant circuit having surplus capacity. The operating method of the air conditioner, wherein the operating capacity of the compressor or the refrigerant pump is adjusted in some cases.