JP2002243319A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a useless defrosting. SOLUTION: An outdoor heat exchanger and indoor heat exchanging parts (62, 63) are provided. A plurality of refrigerant circuits (14, 15) capable of a heating operation having a normal cycle and a defrosting operation having a reverse cycle. The indoor heat exchanging parts (62, 63) are arranged closely to each other so as to perform a heat exchange between refrigerants of the refrigerant circuits (14, 15). When any one of the plural refrigerant circuits (14, 15) performs the defrosting operation, a defrosting control unit (91) controls other refrigerant circuits (14, 15) to perform the heating operation. An operation control unit (92) controls an order of defrosting operation so that any one of the plural refrigerant circuits (14, 15) performs the defrosting operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to a measure for controlling defrost.

[0002]

2. Description of the Related Art Conventionally, air conditioners include compressors,
2. Description of the Related Art A plurality of refrigerant circuits connected to an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are known. In this type of air conditioner, when the frost is detected in any one of the outdoor heat exchangers during the heating operation when the outdoor temperature is considerably low, the other outdoor heat exchangers also form frost. Therefore, the circulation direction of the refrigerant is reversed in all the refrigerant circuits. Then, a high-temperature refrigerant discharged from the compressor is caused to flow into the outdoor heat exchanger, thereby performing a reverse cycle defrost operation for defrosting frost adhering to the outdoor heat exchanger.

[0003]

However, in the above air conditioner, when the outdoor heat exchanger is defrosted, if the outdoor heat exchanger is not frosted, the outdoor heat exchanger is connected. Even in the refrigerant circuit, the defrost operation in the reverse cycle is performed, so that the outdoor heat exchanger without frost cannot not only perform the heating operation but also perform the useless defrost operation.

[0004] The present invention has been made in view of the above, and has as its object to prevent useless defrost.

[0005]

According to the present invention, one of the refrigerant circuits (14, 15) performs a defrost operation, and the other refrigerant circuit (14, 15) performs a heating operation. The amount of heat is input from the refrigerant circuit (14, 15) that performs the operation to the refrigerant circuit (14, 15) that performs the defrost operation.

Specifically, a first solution is to provide a refrigerant circuit (22) having a heat source side heat exchanger (22, 48) and a use side heat exchanger (62, 63) and performing a reverse cycle defrost during a heating operation. 14,1
Assuming an air conditioner having a plurality of 5), when any one of the plurality of refrigerant circuits (14, 15) performs the defrost operation, the other refrigerant circuits (14, 15) are operated for heating, and the defrost operation is performed. The amount of heat is input from the refrigerant in the refrigerant circuits (14, 15) performing the heating operation to the refrigerant in the refrigerant circuits (14, 15) performing the operation.

A second solution is to provide a heat source side heat exchanger (22, 48) and a use side heat exchanger (62, 63). Assuming that the air conditioner includes a plurality of possible refrigerant circuits (14, 15), each of the usage-side heat exchangers (62, 63) of the plurality of refrigerant circuits (14, 15) includes a refrigerant circuit (14, 15). The refrigerant circuit (14, 15) is disposed in close proximity to the refrigerant circuit (15) so that heat exchange is possible, and when any one of the plurality of refrigerant circuits (14, 15) performs the defrost operation, the other refrigerant circuit (14, 15) A defrost means (91) for performing a heating operation is provided.

[0008] A third solution is to provide a heat source side heat exchanger (22, 48) and a use side heat exchanger (62, 63). Assuming that the air conditioner includes a plurality of possible refrigerant circuits (14, 15), each of the usage-side heat exchangers (62, 63) of the plurality of refrigerant circuits (14, 15) includes a refrigerant circuit (14, 15). 15) The refrigerant circuit (14, 15) that performs defrost operation among the plurality of refrigerant circuits (14, 15) is arranged in one of the refrigerant circuits (14, 15). Operation control means (92) for controlling the order of the defrost operation so that the refrigerant of the refrigerant circuit (14, 15) for performing the defrost operation and the refrigerant of the refrigerant circuit (14, 15) for performing the heating operation are used. Side heat exchanger (62,
A defrost means (91) for performing a defrost operation for exchanging heat in 63) is provided.

A fourth solution of the above-described first to third means is to provide a blower (80) for blowing air to the use-side heat exchangers (62, 63) while operating the defrost operation. At times, the blower (80) is stopped.

That is, in the first solving means, during the heating operation, one of the plurality of refrigerant circuits (14, 15) performs the reverse cycle defrost operation while the other refrigerant circuits (14, 15) operate. ) Continues the heating operation. During the defrost operation, the amount of heat from the refrigerant in the refrigerant circuits (14, 15) performing the heating operation is input to the refrigerant in the refrigerant circuits (14, 15) performing the defrost operation. The heat input from the refrigerant in the refrigerant circuits (14, 15) performing the heating operation is used for defrosting the heat source side heat exchangers (22, 48).

In the second solution, during the heating operation, one of the plurality of refrigerant circuits (14, 15) performs the reverse cycle defrost operation while the other refrigerant circuits (14, 15) operate. ) Continues the heating operation. In each use side heat exchanger (62, 63), heat exchange is performed between the refrigerants in the refrigerant circuits (14, 15), and defrost operation is performed from the refrigerant in the refrigerant circuits (14, 15) that perform the heating operation. An amount of heat is input to the refrigerant in the refrigerant circuits (14, 15). The heat input from the refrigerant in the refrigerant circuits (14, 15) performing the heating operation is used for defrosting the heat source side heat exchangers (22, 48).

[0012] In the third solution, the operation control means (92) performs the refrigerant circuit (14,1) for performing the defrost operation.
The order of the defrost operation is controlled so that 5) is any one. During the heating operation, one of the plurality of refrigerant circuits (14, 15) performs the reverse cycle defrost operation, while the other refrigerant circuits (14, 15) continue the heating operation.
In each use side heat exchanger (62, 63), each refrigerant circuit (14,
Heat is exchanged between the refrigerants in 15), and heat is input from the refrigerant in the refrigerant circuits (14, 15) performing the heating operation to the refrigerant in the refrigerant circuits (14, 15) performing the defrost operation. The heat input from the refrigerant in the refrigerant circuits (14, 15) performing the heating operation is used for defrosting the heat source side heat exchangers (22, 48).

Further, in the fourth solution, the first solution
In any one of the third to third solutions, the blower (80) is stopped during the defrost operation, and the use-side heat exchanger (6
Stop the ventilation to 2,63).

[0014]

Therefore, according to the first solution,
Since any one of the refrigerant circuits (14, 15) performs the defrost operation while the other refrigerant circuit (14, 15) performs the heating operation, the non-frosted heat source side heat exchanger (22, Four
The unnecessary defrost in 8) can be prevented, and the refrigerant circuit (14, 15) without frost can continue the heating operation. Further, the refrigerant circuit (14, 15) performing the defrost operation from the refrigerant circuit (14, 15) performing the heating operation.
Since the heat quantity is input in 5), the de-defrost time can be reduced.

According to the second solution, the use side heat exchangers (62, 63) are arranged so that the refrigerant in each of the refrigerant circuits (14, 15) can exchange heat. The amount of heat can be reliably input from the refrigerant in the refrigerant circuit (14, 15) performing the defrost operation to the refrigerant in the refrigerant circuit (14, 15) performing the defrost operation.

According to the third solution, the order of the defrost operation is controlled, so that only one refrigerant circuit (14, 15) can reliably perform the defrost operation.

According to the fourth solution, since the blower (80) is stopped during the defrost operation, the heat of the refrigerant in the refrigerant circuit (14, 15) performing the heating operation radiates to the air. Can be suppressed, and heat exchange between the refrigerants can be performed efficiently.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, an air conditioner (10)
Are configured to switch between a cooling operation and a heating operation.

The air conditioner (10) includes a first outdoor unit (11) and a second outdoor unit (12) which are heat source side units, and one indoor unit (13) which is a use side unit. , So-called multi-type.
Further, the air conditioner (10) includes a first refrigerant circuit (14).
And a second refrigerant circuit (15) and a controller (90).

The first refrigerant circuit (14) includes a first outdoor circuit (20), a first indoor circuit (60), and a first liquid side communication pipe (1).
6) and a first gas side communication pipe (17). The second refrigerant circuit (15) includes a second outdoor circuit (85).
A second indoor circuit (86), a second liquid side communication pipe (18),
It is constituted by a second gas side communication pipe (19).

The first outdoor circuit (20) is housed in a first outdoor unit (11) as shown in FIG. The outdoor circuit (20) includes a first compression mechanism (40), a first four-way switching valve (21), a first outdoor heat exchanger (22), and a first receiver (2).
3), a first outdoor expansion valve (24), a liquid-side stop valve (25), and a gas-side stop valve (26).

The second outdoor circuit (85) includes a second compression mechanism (46), a second four-way switching valve (47), and a second outdoor heat exchanger (4).
8), a second receiver (49), and a second outdoor expansion valve (50) as main components. The second outdoor circuit (85)
Has the same configuration as that of the first outdoor circuit (20), the configuration of the first outdoor circuit (20) will be described below, and the description of the configuration of the second outdoor circuit (85) will be omitted.

The first compression mechanism (40) has a first compressor (41) and a second compressor (42) connected in parallel, and is configured as a so-called twin compressor. The first compressor (41)
The second compressor (42) is a high-pressure dome hermetic scroll compressor. That is, the first compressor (4
The first and second compressors (42) are configured by housing a compression element and an electric motor for driving the compression element in a cylindrical housing.

The first compressor (41) is a compressor having a constant capacity in which the electric motor is constantly driven at a constant rotation speed. The second compressor (42) is a variable capacity compressor in which the number of revolutions of the electric motor is changed stepwise or continuously in multiple stages. That is, in the second compressor (42), the rotation speed of the electric motor is controlled by the inverter. The first compression mechanism (40)
Drive and stop of the first compressor (41) and the second compressor (4
By changing the capacity in 2), the entire capacity is variably adjusted.

The first compression mechanism (40) includes a suction pipe (43)
And a discharge pipe (44). The suction pipe (43) has an inlet end connected to the first port of the first four-way switching valve (21), and an outlet end branched into two suction branch pipes (43a, 43b). The suction branch pipe (43a, 43b) is connected to each compressor (41,
42) is connected to the suction side.

The discharge pipe (44) has an inlet end branched into two discharge branch pipes (44a, 44b), and an outlet end connected to a second port of the first four-way switching valve (21). ing. The discharge branch pipes (44a, 44b) are connected to the discharge sides of the compressors (41, 42). The discharge branch pipe (44a) connected to the first compressor (41) is provided with a discharge-side check valve (45). The discharge-side check valve (45) allows only the refrigerant to flow in the direction flowing out of the first compressor (41).

The first compression mechanism (40) includes an oil separator (51), an oil return pipe (52), and an oil equalizing pipe (54). The oil separator (51) is provided in a main pipe portion of a discharge pipe (44) in which refrigerant discharged from the first compressor (41) and the second compressor (42) flows together. The oil separator (51) is for separating oil from refrigerant discharged from the compressors (41, 42). One end of the oil return pipe (52) is connected to the oil separator (51), and the other end is connected to the suction branch pipe (43) of the first compressor (41).
a) connected to The oil return pipe (52) is for returning the oil separated by the oil separator (51) to the suction side of the compressors (41, 42), and includes an oil return solenoid valve (53). ing. The oil return solenoid valve (53) opens and closes to open and close the oil return pipe (52).

One end of the oil equalizing pipe (54) is connected to the first compressor (41), and the other end is connected to the suction branch pipe (43b) of the second compressor (42). The oil equalizing pipe (54) is for averaging the amount of oil stored in the housing of each compressor (41, 42), and includes an oil equalizing solenoid valve (55). The oil equalizing solenoid valve (55) opens and closes so as to communicate and shut off the oil equalizing pipe (54).

The third port of the first four-way switching valve (21) is connected to the gas side shut-off valve (26) by a pipe, and the fourth port is connected to the upper end of the first outdoor heat exchanger (22). Section and piping connection. The first four-way switching valve (21) has a state in which the first port and the third port are in communication and the second port and the fourth port are in communication (a state shown by a solid line in FIG. 2); The first port communicates with the fourth port, and the second port communicates with the third port.
(A state shown by a broken line in FIG. 2). By the switching operation of the first four-way switching valve (21), the circulation direction of the refrigerant in the first refrigerant circuit (14) is reversed. That is, in the first refrigerant circuit (14), the circulation direction of the refrigerant is configured to be reversible.

The first receiver (23) is a cylindrical container for storing a refrigerant. The first receiver (23) and the first outdoor expansion valve (24) are provided in a rectifier circuit (30). The rectifier circuit (30) is composed of a bridge circuit (31) having four check valves, and a one-way passage (32) through which refrigerant flows only in one direction, and includes a first outdoor heat exchanger (22). It is provided between the liquid-side stop valve (25).

The first connection end of the four connection ends of the bridge circuit (31) is connected to the lower end of the first outdoor heat exchanger (22), and the second connection end of the bridge circuit (31). The end is
It is connected to the liquid side shutoff valve (25).

The third connection terminal and the fourth connection terminal of the bridge circuit (31) are connected to both ends of a one-way passage (32). In the one-way passage (32), the first receiver (23) and the first outdoor expansion valve (24) are sequentially connected from the upstream side, and the refrigerant flows from the first receiver (23) to the first outdoor expansion valve (24). It is configured to flow only in the direction toward.

The first heat source side heat exchanger (22, 48)
The outdoor heat exchanger (22) is configured by a cross-fin type fin-and-tube heat exchanger. The first
The outdoor heat exchanger (22) exchanges heat between the refrigerant circulating in the first refrigerant circuit (14) and the outdoor air.

Further, the outdoor circuit (20) is provided with a degassing pipe (35) and a pressure equalizing pipe (37). One end of the gas vent pipe (35) is connected to the upper end of the first receiver (23), and the other end is connected to the suction pipe (43). The degassing pipe (35) is for introducing the gas refrigerant of the first receiver (23) to the suction side of each compressor (41, 42). The degassing pipe (35) has a degassing solenoid valve (36)
Is provided.

One end of the pressure equalizing pipe (37) is connected between the gas release solenoid valve (36) and the first receiver (23) in the gas release pipe (35), and the other end is connected to the discharge pipe (44). It is connected. Further, the pressure equalizing pipe (37) is provided with a pressure equalizing check valve (38) that allows only the flow of the refrigerant from one end to the other end. The equalizing pipe (37) allows the gaseous refrigerant to escape when the outside air temperature rises abnormally while the air conditioner (10) is stopped and the pressure in the first receiver (23) becomes too high. (23) is to prevent rupture.

The first outdoor unit (11) is provided with an outdoor fan (70). The outdoor fan (70)
This is for sending outdoor air to the first outdoor heat exchanger (22).

The first indoor circuit (60) and the second indoor circuit (86) are provided in the indoor unit (13) as shown in FIG. The indoor unit (13) includes an indoor heat exchanger (61). The indoor heat exchanger (61) is a first indoor heat exchanger (62), which is a use side heat exchanger of the first refrigerant circuit (14), and a use side heat exchanger of the second refrigerant circuit (15). A second indoor heat exchange section (63). In the indoor heat exchanger (61), the first indoor heat exchange section (62) and the second indoor heat exchange section (63) are connected by fins (64) and are integrally formed.

The fins (64) of the indoor heat exchanger (61)
Improves the heat exchange capacity between the refrigerant circulating in the first refrigerant circuit (14) and the indoor air, and also improves the heat exchange capacity between the refrigerant circulating in the second refrigerant circuit (15) and the indoor air.
Further, the fins (64) exchange heat between the refrigerant in the first indoor heat exchange section (62) and the refrigerant in the second indoor heat exchange section (63). That is, the indoor heat exchange sections (62, 63) are arranged so that the refrigerant of the first refrigerant circuit (14) and the refrigerant of the second refrigerant circuit (15) can exchange heat with each other.

The indoor unit (13) has a blower (8)
0) is provided for the indoor fan (80). The indoor fan (80) is for sending indoor air to the indoor heat exchanger (61).

One end of the first liquid side communication pipe (16) is the first liquid side communication pipe (16).
The other end is connected to the lower end of the first indoor heat exchanger (62), which is connected to the liquid side shut-off valve (25) of the outdoor circuit (20). One end of the first gas side communication pipe (17) has a first outdoor circuit (2).
0), and the other end is connected to the upper end of the first indoor heat exchange section (62). One end of the second liquid side communication pipe (18) is connected to the liquid side shutoff valve (25) of the second outdoor circuit (85), and the other end is connected to the lower end of the second indoor heat exchange unit (63). Have been. One end of the second gas side communication pipe (19) is connected to the gas side shutoff valve (26) of the second outdoor circuit (85), and the other end is connected to the upper end of the second indoor heat exchange section (63). Have been.

As shown in FIGS. 1 and 2, the air conditioner (10) is provided with temperature and pressure sensors and the like. Specifically, the first outdoor unit (11) is provided with an outdoor temperature sensor (71) for detecting the temperature of outdoor air. The first outdoor heat exchanger (22) is provided with an outdoor heat exchange temperature sensor (72) for detecting a heat transfer tube temperature. The suction pipe (4) of the first compression mechanism (40)
3) includes a suction temperature sensor (73) for detecting a suction refrigerant temperature of the first compression mechanism (40), and a first compression mechanism (4).
0) low-pressure pressure sensor (7
4) is provided. In addition, the first compression mechanism (4
A discharge temperature sensor (75) for detecting a refrigerant temperature discharged from the first compression mechanism (40) and a refrigerant pressure discharged from the first compression mechanism (40) are provided in the discharge pipe (44) of (0). Pressure sensor (76) and a high pressure switch (77) are provided. Similarly to the first outdoor unit (11), the second outdoor unit (12) is provided with a temperature and pressure sensor and the like.

The indoor unit (13) is provided with an indoor temperature sensor (81) for detecting the temperature of indoor air. The first indoor heat exchange unit (62) is provided with a first indoor heat exchange temperature sensor (82) for detecting a heat transfer tube temperature, and the second indoor heat exchange unit (63) is provided with a heat transfer tube temperature. A second indoor heat exchange temperature sensor (83) for detecting the temperature is provided.

The controller (90) controls the operation of the air conditioner (10) in response to signals from the sensors and command signals from a remote controller or the like. Specifically, the controller (90) controls each outdoor expansion valve (24, 5
0), the four-way switching valves (21, 47) are switched, and the venting solenoid valves (36) are opened and closed. The controller (90) also controls the capacity of each compression mechanism (40, 46).

The controller (90) includes a defrost control section (91) and an operation control section (92).

The defrost control section (91) constitutes defrost control means, and is configured so that when one of the refrigerant circuits (14, 15) performs the defrost operation, the other performs the heating operation. I have. The defrost controller (91) switches the first four-way switching valve (21) to the state shown by the solid line in FIG. 1 when performing defrosting of the first outdoor heat exchanger (22) during the heating operation. The first refrigerant circuit (14) is configured to perform the reverse cycle defrost operation, and the second refrigerant circuit (15) is configured to continue the normal cycle heating operation.
That is, in the defrost of the first outdoor heat exchanger (22), the heat amount of the high-temperature refrigerant discharged from the first compression mechanism (40) is used for the defrost of the first outdoor heat exchanger (22). The amount of heat of the high-temperature refrigerant discharged from the second compression mechanism (46) is input to the refrigerant of the first refrigerant circuit (14) by heat exchange between the indoor heat exchange units (62, 63), and the first outdoor heat Used for defrosting the exchanger (22).

The defrost controller (91) is configured to switch the second four-way switching valve (47) when defrosting the second outdoor heat exchanger (48) during the heating operation. I have. That is, in the defrost of the second outdoor heat exchanger (48), the heat amount of the high-temperature refrigerant discharged from the second compression mechanism (46) is used for the defrost of the second outdoor heat exchanger (48), and The amount of heat of the high-temperature refrigerant discharged from the first compression mechanism (40) is input to the refrigerant in the second refrigerant circuit (15) by heat exchange between the indoor heat exchange units (62, 63), and the second outdoor heat exchange is performed. Used for defrosting the vessel (48).

The defrost controller (91) is configured to stop the indoor fan (80) when one of the refrigerant circuits (14, 15) performs the defrost operation.

The operation control section (92) constitutes operation control means. That is, when the frost formation is detected in both outdoor heat exchangers (22, 48), the operation control unit (92) performs the defrosting so that the refrigerant circuit (14, 15) performing the defrosting operation becomes one of the refrigerant circuits. It is configured to control the order of operation. That is, even when frost formation is detected in both outdoor heat exchangers (22, 48), one of the refrigerant circuits (14, 15) performs the defrost operation and the other refrigerant circuit (14, 1).
5) Continue heating operation. The order of performing the defrost operation is determined based on, for example, the temperature of the heat transfer tubes detected by the outdoor heat exchange temperature sensor (72).

-Operating operation- In the air conditioner (10) described above, the refrigerant circulates in the first refrigerant circuit (14) and the second refrigerant circuit (15) while changing the phase to perform a vapor compression refrigeration cycle. . The air conditioner (10) switches between the cooling operation and the heating operation by reversing the direction of circulation of the refrigerant in both refrigerant circuits (14, 15). Further, during the heating operation, when frost formation in the outdoor heat exchangers (22, 48) is detected, one of the refrigerant circuits (14, 15) is switched to the reverse cycle for operation.

-Heating Operation- During the heating operation, a heating operation is performed in which the indoor heat exchanger (61) becomes a condenser. During the heating operation, the four-way switching valves (21, 47) are in the state shown by the broken lines in FIG. Each outdoor expansion valve (24, 50) is adjusted to a predetermined opening degree, and each oil return solenoid valve (53) and each oil equalizing solenoid valve (55) are opened and closed appropriately. Each degassing solenoid valve (36) is always kept open during the heating operation. These valve operations are performed by the controller (90).

In the first outdoor circuit (20), the refrigerant compressed by the first compression mechanism (40) is discharged to the discharge pipe (44), the first four-way switching valve (21), and the first liquid side communication pipe (16). ) To the first indoor heat exchange section (62). The first indoor heat exchange section (62)
In, the refrigerant radiates heat to room air and condenses. The condensed refrigerant flows through the first liquid side communication pipe (16), flows through the bridge circuit (31) and the one-way passage (32), expands at the first outdoor expansion valve (24), and causes the first outdoor heat exchange. Into the vessel (22).

The refrigerant in the first outdoor heat exchanger (22) absorbs heat from outdoor air and evaporates. The evaporated refrigerant passes through the first four-way switching valve (21), returns to the first compression mechanism (40) through the suction pipe (43). Such circulation of the refrigerant is repeated.

In the second outdoor circuit (85), the refrigerant compressed by the second compression mechanism (46) flows through the second four-way switching valve (47) and the second gas side communication pipe (19). The refrigerant in the second gas side communication pipe (19) flows into the second indoor heat exchange section (63), radiates heat to indoor air and condenses. In the heating operation, the first indoor heat exchange unit (62) and the second indoor heat exchange unit (63)
Since the refrigerant having the same temperature flows in and condenses, the refrigerant does not exchange heat between the indoor heat exchange sections (62, 63). The condensed refrigerant flows through the second liquid side communication pipe (18), flows into the second outdoor circuit (85), flows through the bridge circuit (31) and the one-way passage (32), and flows through the second outdoor expansion valve (50). ) And flows into the second outdoor heat exchanger (48). Thereafter, the refrigerant passes through the second four-way switching valve (47), returns to the second compression mechanism (46) through the suction pipe (43). Such circulation of the refrigerant is repeated.

-Cooling operation- During the cooling operation, a cooling operation in which the indoor heat exchanger (61) becomes an evaporator is performed. During the cooling operation, each four-way switching valve (21, 47) is in a state shown by a solid line in FIG. Each outdoor expansion valve (24, 50) is adjusted to a predetermined opening degree, each degassing solenoid valve (36) is kept closed, each oil return solenoid valve (53) and each oil equalizing solenoid valve (55) Is opened and closed as appropriate. These valve operations are performed by the controller (90).

In this case, in each of the refrigerant circuits (14, 15), the refrigerant circulates in a direction basically opposite to that in the heating operation. That is, the refrigerant radiates heat to the outdoor air, condenses, absorbs heat from the indoor air, evaporates, and cools the room. The details of the flow of the refrigerant are omitted.

-Defrosting Operation of First Refrigerant Circuit-A defrosting operation performed when only the first outdoor heat exchanger (22) detects frost formation during the heating operation will be described. During this defrost operation, the first four-way switching valve (21) is switched to the state shown by the solid line in FIG. 2, and the first refrigerant circuit (14) performs the reverse cycle defrost operation and the second refrigerant circuit (15). In), the heating operation in the normal cycle is continued. Then, the indoor fan (80) installed in the indoor unit (13) is stopped.

In the first outdoor circuit (20), the high-temperature refrigerant compressed by the first compression mechanism (40) is supplied to the first four-way switching valve (2).
Through 1), it flows into the first outdoor heat exchanger (22). The high-temperature refrigerant is supplied to the low-temperature first outdoor heat exchanger (22).
Is heated to melt and condense the attached frost. The condensed refrigerant flows through the bridge circuit (31) and the one-way passage (32), flows through the first liquid-side communication pipe (16), and flows into the first indoor heat exchange section (62).

On the other hand, in the second outdoor circuit (85), the second outdoor circuit (85)
The high-temperature refrigerant compressed by the compression mechanism (46) passes through the second four-way switching valve (47), flows through the second gas-side communication pipe (19),
It flows into the second indoor heat exchange section (63).

Then, heat is exchanged between the indoor heat exchange sections (62, 63), and the refrigerant in the first indoor heat exchange section (62) is
The amount of heat from the high-temperature refrigerant in the indoor heat exchange section (63) is input,
While being heated and evaporated, the refrigerant in the second indoor heat exchange section (63) is condensed. At this time, the indoor fan (80) is stopped, and the heat of the refrigerant in the second indoor heat exchange section (63) is suppressed from radiating to the indoor air.

The refrigerant evaporated in the first indoor heat exchange section (62) flows through the first gas-side communication pipe (17), and flows through the first compression mechanism (4).
Inhaled at 0). The refrigerant sucked into the first compression mechanism (40) is compressed and the temperature further rises, is discharged from the first compression mechanism (40), passes through the first four-way switching valve (21), It flows into the first outdoor heat exchanger (22). The refrigerant whose temperature has risen melts frost attached to the first outdoor heat exchanger (22), defrosts it, and condenses. That is, the amount of heat input from the second refrigerant circuit (15) is used for defrosting in the first outdoor heat exchanger (22). Then, such a circulation is repeated.

On the other hand, the refrigerant condensed in the second indoor heat exchange section (63) flows through the second liquid side communication pipe (18), flows through the bridge circuit (31) and the one-way passage (32), and is decompressed. It flows into the second outdoor heat exchanger (48). The second outdoor heat exchanger (4
The refrigerant flowing into 8) exchanges heat with outdoor air and evaporates, and returns to the second compression mechanism (46). Such a circulation is repeated.

-Defrosting Operation of Second Refrigerant Circuit- A description will be given of a defrosting operation performed when only the second outdoor heat exchanger (48) detects frost formation during the heating operation. In the defrost operation, the refrigerant basically circulates in a direction opposite to the defrost operation of the first refrigerant circuit (14). That is, during the defrost operation, the first refrigerant circuit (14) continues the heating operation, and the second refrigerant circuit (15) performs the defrost operation. Then, the indoor fan (80) installed in the indoor unit (13) is stopped.

In the first refrigerant circuit (14), the high-temperature refrigerant discharged from the first compression mechanism (40) flows into the first indoor heat exchange section (62). In the second refrigerant circuit (15), the high-temperature refrigerant discharged from the second compression mechanism (46) melts frost adhering to the second outdoor heat exchanger (48) and condenses.
It flows into the indoor heat exchange section (63). Then, heat exchange is performed between the indoor heat exchange units (62, 63), and the first refrigerant circuit (14)
Is input to the second refrigerant circuit (15) with a phase change. At this time, the indoor fan (80) is stopped. The refrigerant in the second refrigerant circuit (15) is the second compression mechanism (46)
It is further compressed and becomes hot, and the second outdoor heat exchanger (48)
Defrosting is performed by melting the frost adhering to the surface. That is, the amount of heat input from the first refrigerant circuit (14) is used for defrost in the second outdoor heat exchanger (48). Such a circulation is repeated.

On the other hand, the refrigerant flowing out of the first indoor heat exchange section (62) passes through the bridge circuit (31) and the one-way passage (32), and exchanges heat with outdoor air in the first outdoor heat exchanger (22). Replace and return to the first compression mechanism (40). Such a circulation is repeated.

-Defrost Operation of Both Refrigerant Circuits- A description will be given of a defrost operation performed when frost formation is detected in the outdoor heat exchangers (22, 48) during the heating operation. In this defrost operation, first, only one refrigerant circuit (14, 15) is switched to the reverse cycle to perform the defrost operation, and the other refrigerant circuit (14, 15)
Continue heating operation. Then, the one refrigerant circuit (1
(4,15), the refrigerant circuits (14,1)
Switch the circulation direction of 5). Therefore, the heating operation is performed in the one refrigerant circuit (14, 15), and the defrost operation is performed in the other refrigerant circuit (14, 15). Which of the refrigerant circuits (14, 15) performs the defrost operation first is determined, for example, by the heat transfer tube temperature of the outdoor heat exchanger (22, 48). The details of the circulation of the refrigerant will be omitted.

-Effects of Embodiment- According to the present embodiment, any one of the refrigerant circuits (14, 15)
Performs defrost operation while other refrigerant circuits (14, 15)
Performs the heating operation, it is possible to prevent unnecessary defrost in the non-frosted outdoor heat exchangers (22, 48), and to prevent the non-frosted refrigerant circuit (14, 1
In 5), the heating operation can be continued. Further, the amount of heat is input from the refrigerant circuits (14, 15) performing the heating operation to the refrigerant circuits (14, 15) performing the defrost operation, so that the de-defrost time can be reduced.

Since the refrigerant in each of the refrigerant circuits (14, 15) constitutes a heat exchange section (62, 63) in both indoors so that heat can be exchanged, the refrigerant circuits (14, 15) for performing a heating operation are provided. The amount of heat can be reliably input from the refrigerant to the refrigerant in the refrigerant circuits (14, 15) that perform the defrost operation.

Since the order of the defrost operation is controlled, only one refrigerant circuit (14, 15) can surely perform the defrost operation.

Also, the indoor fan (8
0) is stopped, so that the heat of the refrigerant in the refrigerant circuit (14, 15) performing the heating operation can be suppressed from being radiated to the air, and the heat exchange between the refrigerants can be performed efficiently. .

<Other Embodiments of the Invention> In the above embodiment, two refrigerant circuits (14, 15) are provided. Instead, three or more refrigerant circuits (14, 15) are provided. It may be configured. In this case, it is preferable that only one of the refrigerant circuits (14, 15) performs the defrost operation, and the other refrigerant circuits (14, 15) perform the heating operation.

Further, in the above embodiment, the indoor heat exchange sections (62, 63) are formed integrally, but it is not always necessary to form them integrally. It is sufficient that the refrigerants are configured to be able to exchange heat.

In the above embodiment, the indoor fan (80) is stopped during the defrost operation.
Instead, the configuration may be such that the number of revolutions of the indoor fan (80) is reduced.

[Brief description of the drawings]

FIG. 1 is a refrigerant system diagram illustrating an overall configuration of an air-conditioning apparatus according to an embodiment.

FIG. 2 is a refrigerant system diagram showing a configuration of a first outdoor unit according to the embodiment.

[Explanation of symbols]

 (14) First refrigerant circuit (15) Second refrigerant circuit (22) First outdoor heat exchanger (48) Second outdoor heat exchanger (62) First indoor heat exchanger (63) Second indoor heat exchanger (80) Indoor fan (91) Defrost control unit (92) Operation control unit

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) F25B 13/00 F25B 13/00 U (72) Inventor Masaaki Takegami 1304 Kanaokacho, Sakai-shi, Osaka Daikin Industries Sakai Co., Ltd. Inside the factory Kanaoka factory (72) Inventor Kazuhide Nomura 1304 Kanaokacho, Sakai-shi, Osaka Daikin Industries Inside the Sakai factory Kanaoka factory F-term (reference) 3L092 AA02 AA03 AA09 BA01 BA15 DA02 EA20 FA19 FA22 FA36

Claims (4)

[Claims] An air having a heat source side heat exchanger (22, 48) and a use side heat exchanger (62, 63), and having a plurality of refrigerant circuits (14, 15) for performing reverse cycle defrost during heating operation. A harmony device, wherein when any one of the plurality of refrigerant circuits (14, 15) performs a defrost operation, the other refrigerant circuits (14, 15) perform a heating operation to perform a defrost operation. An air conditioner, wherein heat is input from a refrigerant in a refrigerant circuit (14, 15) that performs a heating operation to the refrigerant in 15). 2. A refrigerant circuit (1) having a heat source side heat exchanger (22, 48) and a use side heat exchanger (62, 63) and capable of performing a defrost operation in a reverse cycle together with a heating operation in a normal cycle.
An air conditioner comprising a plurality of refrigerant circuits (14, 15), wherein each of the use-side heat exchangers (62,
63) is disposed close to the refrigerant circuits (14, 15) so that heat can be exchanged between the refrigerant circuits, while one of the plurality of refrigerant circuits (14, 15) performs a defrost operation. An air conditioner comprising a defrost means (91) for causing another refrigerant circuit (14, 15) to perform a heating operation. 3. A refrigerant circuit (1) having a heat source side heat exchanger (22, 48) and a use side heat exchanger (62, 63) and capable of performing a reverse cycle defrost operation together with a normal cycle heating operation.
An air conditioner comprising a plurality of refrigerant circuits (14, 15), wherein each of the use-side heat exchangers (62,
63) is disposed close to the refrigerant circuits (14, 15) so that heat can be exchanged between the refrigerant circuits, and the refrigerant circuit (14, 15) that performs a defrost operation among the plurality of refrigerant circuits (14, 15). Operation control means (92) for controlling the order of the defrost operation so that the refrigerant circuit (14, 15) becomes one of the refrigerant circuits (14, 15) and the refrigerant circuit (14, 15) for performing the defrost operation and the refrigerant circuit (for performing the heating operation) 14. An air conditioner comprising a defrost means (91) for performing a defrost operation for exchanging heat with the refrigerant of the heat exchangers (14, 15) in the use-side heat exchangers (62, 63). 4. The air conditioner according to claim 1, further comprising a blower (80) for blowing air to the use-side heat exchangers (62, 63), and stopping the blower (80) during a defrost operation. An air conditioner characterized by the above-mentioned.