JPH10205933A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner capable of keeping indoor temperature stable by a method wherein an outdoor heat exchanger is split into two parts, two outdoor heat exchangers are switched with one part as a condenser and the other as an evaporator even when the heat exchanger is frosted during the heating operation. SOLUTION: In an air conditioner comprising a compressor 1, a four-way valve 2, an outdoor side heat exchanger, and expansion valve 4, and an indoor side heat exchanger 5 connected to each other to form the refrigerating cycle, the outdoor heat exchanger is split into a first outdoor heat exchanger 3a and a second outdoor heat exchanger 3b in series through an auxiliary expansion valve 6, a first opening/ closing valve 7 is provided on the inlet side of the expansion valve 4 and the first outdoor heat exchanger 3a, a second opening/closing valve 8 is provided on the outlet side of the expansion valve 4 and the second outdoor heat exchanger 3b, a third opening/closing valve 9 is provided on the outlet side of the four-way valve 2 and the first outdoor heat exchanger 3a, and a fourth opening/closing 10 is provided on the inlet side of the four-way valve 2 and the first outdoor heat exchanger 3a. Defrosting can be performed during the heating operation by throttling the expansion valve 4 and the auxiliary expansion valve 6 and switching each opening/closing valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an air conditioner capable of performing a defrosting operation while performing a heating operation.

[0002]

2. Description of the Related Art A conventional air conditioner forming a refrigeration cycle includes a compressor 1 and a four-way valve 2 as shown in FIG.
, An outdoor-side heat exchanger 3 ', an expansion valve (or a capillary tube) 4', and an indoor-side heat exchanger 5 ', which are annularly connected by a refrigerant pipe. With the above configuration,
In FIG. 4, the solid arrows indicate the refrigerant flow directions during the cooling operation and the defrosting operation, and the broken arrows indicate the refrigerant flow directions during the heating operation. In the above air conditioner, during the heating operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 in the outdoor unit passes through the four-way valve 2 and then passes through the indoor heat exchanger 5 ′.
The heat exchanges with the indoor air while flowing through the air, thereby releasing and condensing the heat into the room. The condensed and liquefied liquid refrigerant is decompressed through the expansion valve 4 ', becomes a low-temperature low-pressure gas-liquid two-phase, is absorbed by outdoor air while flowing through the outdoor heat exchanger 3', and becomes a low-temperature low-pressure gas refrigerant. It is returned from the four-way valve 2 to the compressor 1.
At the time of cooling operation, by switching the four-way valve 2,
The operation is the same as that of the heating except that the functions of the indoor heat exchangers 3 ′ and 5 ′ are reversed.

When the outside air temperature is low and the humidity is high, frost forms on the outdoor heat exchanger 3 'during the heating operation, and the heating capacity is reduced. In such a case, the flow of the refrigerant is changed by the four-way valve 2 (cooling cycle), and the defrosting operation starts. However, the defrosting operation requires a certain defrosting time, and during this time, the heating operation is not performed. Therefore, the room temperature decreases, and the room temperature does not immediately rise when the defrosting is completed and the heating operation is restarted. However, there has been a problem that the temperature of the room becomes unstable.

[0004]

In the present invention, in consideration of the above-mentioned problems, the outdoor heat exchanger is divided into two, and one is used as a condenser and the other is used as an evaporator even if frost forms during the heating operation. An object of the present invention is to provide an air conditioner that can switch between two outdoor heat exchangers and stably maintain the indoor temperature.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and comprises a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger. Become
In an air conditioner formed by connecting these by a refrigerant pipe to form a refrigeration cycle, the outdoor heat exchanger is connected in series via an auxiliary expansion valve to a first outdoor heat exchanger and a second outdoor heat exchanger. A first opening / closing valve is provided on an inlet side of the expansion valve and the first outdoor heat exchanger, and a first bypass is provided on an outlet side of the expansion valve and the second outdoor heat exchanger. A second on-off valve is provided on the first side path, and a third on-off valve is provided on an outlet side of the four-way valve and the second outdoor heat exchanger, and an inlet of the four-way valve and the first outdoor heat exchanger is provided. A second bypass is provided on the side
A fourth on-off valve is provided on the bypass, and the refrigerant is supplied to the first outdoor heat exchanger, the auxiliary expansion valve, and the second outdoor heat by the throttle operation of the expansion valve and the auxiliary expansion valve and the switching operation of each of the on-off valves. Flow in the order of the exchanger, or the first side path, the second outdoor side heat exchanger, the auxiliary expansion valve, the first outdoor side heat exchanger, the second side side path, and either the first or the outdoor side heat exchanger. One of which is a condenser,
The other is set as an evaporator, and these are alternately switched so that defrosting can be performed during the heating operation.

Further, the auxiliary expansion valve is constituted by an electronic expansion valve capable of changing the throttle amount. In addition, each of the on-off valves is configured to use an electromagnetic valve.

Further, when the first outdoor heat exchanger is frosted, the expansion valve is fully opened, the auxiliary expansion valve is throttled to a predetermined amount, and the first and third on-off valves are opened. ,
The second on-off valve and the fourth on-off valve are closed.

When the second outdoor heat exchanger is frosted, the expansion valve is fully opened, the auxiliary expansion valve is throttled to a predetermined amount, and the second on-off valve and the fourth on-off valve are opened. ,
The first on-off valve and the third on-off valve are closed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, an outdoor heat exchanger is divided into two parts, and defrosting is performed during a heating operation by a throttle operation of an expansion valve and an auxiliary expansion valve and a switching operation of each open / close valve. With the configuration set to obtain the temperature, the air conditioner can stably maintain the indoor temperature.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 1, 1 is a compressor, 2
Is a four-way valve for switching the flow of refrigerant discharged from the compressor 1 in accordance with a heating operation, a cooling operation, etc., and 3a, 3b are a first outdoor heat exchanger 3a and a second outdoor heat exchanger divided into two. 3b,
Reference numeral 4 denotes an expansion valve, 5 denotes an indoor heat exchanger, and 6 denotes an auxiliary expansion valve comprising an electronic expansion valve having a structure in which a throttle amount can be varied as a throttle mechanism of a refrigerant circuit. Is configured.

The expansion valve 4 and the first outdoor heat exchanger 3a
A first opening / closing valve 7 is provided on the inlet side of the fuel cell, and a first bypass is provided on the outlet side of the expansion valve 4 and the second outdoor heat exchanger 3b.
A second on-off valve 9 is provided on the bypass, a third on-off valve 10 is provided on the outlet side of the four-way valve 2 and the second outdoor heat exchanger 3b, and the four-way valve 2 and the first outdoor heat exchanger are provided. A second bypass is provided on the inlet side of 3a, and a fourth on-off valve 12 is provided on the second bypass.

During cooling and normal heating operation, the auxiliary expansion valve 6 is fully opened, and the first on-off valve 7 and the third on-off valve 10 are opened.
Are opened, and the switching operation of each on-off valve is performed so that the second on-off valve 9 and the fourth on-off valve 12 are closed. FIG. 2 is an equivalent block diagram during the cooling and heating operations. In the cooling operation, the refrigerant circulates as indicated by solid-line arrows, and during the heating operation, the refrigerant circulates as indicated by broken-line arrows.

In the above air conditioner, during the heating operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 in the outdoor unit passes through the four-way valve 2 and then passes through the indoor heat exchanger 5.
The heat exchanges with the indoor air while flowing through the air, thereby releasing and condensing the heat into the room. The condensed and liquefied liquid refrigerant is decompressed through the expansion valve 4 and becomes a low-temperature and low-pressure gas-liquid two-phase, and flows through the first outdoor heat exchanger 3a and the second outdoor heat exchanger 3b by outdoor air. The heat is absorbed and becomes a low-temperature low-pressure gas refrigerant, which is returned from the four-way valve 2 to the compressor 1. During the cooling operation, the four-way valve 2 is switched so that the outdoor and indoor heat exchangers 3 and 5 are switched.
Is the same as in the case of heating except that the action of

During the heating operation, the first outdoor heat exchanger
When frost is formed on the heat exchanger coil due to the heat absorbing action of 3a and the second outdoor heat exchanger 3b, a defrosting operation is performed. In the defrosting operation, when defrosting the first outdoor heat exchanger 3a, the expansion valve 4 is fully opened and the auxiliary expansion valve 6 becomes a throttle device, as shown by defrost A in FIG. , First on-off valve 7
The third on-off valve 10 is opened, and the second on-off valve 9 and the fourth on-off valve 12 are closed. Thereby, as shown in an equivalent block diagram in FIG. 4A, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is guided from the indoor heat exchanger 5 to the first outdoor heat exchanger 3a, The heat is radiated here, and the first outdoor heat exchanger
Frost attached to 3a is defrosted. The refrigerant condensed by the defrosting is depressurized through the auxiliary expansion valve 6, absorbed by the outdoor air while flowing through the second outdoor heat exchanger 3 b, becomes a low-temperature low-pressure gas refrigerant, and flows from the four-way valve 2 to the compressor 1. Will be returned. That is, the first outdoor heat exchanger 3a functions as a condenser,
The outdoor heat exchanger 3b functions as an evaporator.

When defrosting the second outdoor heat exchanger 3b, as shown by defrost B in FIG. 3, the expansion valve 4 is fully opened, and the auxiliary expansion valve 6 becomes a throttle device. Second on-off valve 9
The fourth on-off valve 12 is opened, and the first on-off valve 7 and the third on-off valve 10 are closed. Thereby, as shown in an equivalent block diagram in FIG. 4B, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is guided from the indoor heat exchanger 5 to the second outdoor heat exchanger 3b, The heat is radiated here, and the second outdoor heat exchanger
Frost adhering to 3b is defrosted. The refrigerant condensed by the defrost is depressurized through the auxiliary expansion valve 6, is absorbed by outdoor air while flowing through the first outdoor heat exchanger 3a, becomes a low-temperature low-pressure gas refrigerant, and flows from the four-way valve 2 to the compressor 1. Will be returned. That is, the second outdoor heat exchanger 3b functions as a condenser,
The outdoor heat exchanger 3a functions as an evaporator.

With the above configuration, the outdoor heat exchanger is connected to the first heat exchanger.
The outdoor heat exchanger 3a and the second outdoor heat exchanger 3b are divided into two, and when the outdoor heat exchanger frosts during the heating operation, the frosted chamber is switched by switching the on-off valve. The air conditioner can stably maintain the indoor temperature because the outdoor heat exchanger can be defrosted while performing the heating operation by performing the switching operation operation using the outside heat exchanger as a condenser and the other as an evaporator. Becomes

[0017]

As described above, according to the present invention, since the defrosting of the outdoor heat exchanger can be performed while performing the heating operation, the air conditioner can stably maintain the indoor temperature.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a refrigeration cycle of an air conditioner according to the present invention.

FIG. 2 is an equivalent block diagram of the refrigeration cycle according to the present invention during cooling and heating operations.

FIG. 3 is a diagram showing an operation relationship of an expansion valve, an auxiliary expansion valve, and an on-off valve of the refrigeration cycle according to the present invention.

FIG. 4 is an equivalent block diagram during a defrosting operation of the refrigeration cycle according to the present invention.

FIG. 5 is a diagram showing a refrigeration cycle of an air conditioner according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3a 1st outdoor heat exchanger 3b 2nd outdoor heat exchanger 4 Expansion valve 5 Indoor heat exchanger 6 Auxiliary expansion valve (electronic expansion valve) 7 1st on-off valve 8 1st side path 9 Second on-off valve 10 Third on-off valve 11 Second bypass 12 Fourth on-off valve

Claims (5)

[Claims] 1. An air conditioner comprising a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger, which are connected by a refrigerant pipe to form a refrigeration cycle. In the above, the outdoor heat exchanger is divided into a first outdoor heat exchanger and a second outdoor heat exchanger in series via an auxiliary expansion valve, and the expansion valve and the first outdoor heat exchanger are separated. A first on-off valve is provided on an inlet side, a first side path is provided on an outlet side of the expansion valve and the second outdoor heat exchanger, a second on-off valve is provided on the first side path, and the four-way valve is provided. A third on-off valve is provided on an outlet side of the second outdoor heat exchanger, a second bypass is provided on an inlet side of the four-way valve and the first outdoor heat exchanger, and a fourth bypass is provided on the second bypass. An on-off valve is provided, and refrigerant is supplied to the first outdoor heat exchanger and the auxiliary expansion valve by a throttle operation of the expansion valve and the auxiliary expansion valve and a switching operation of each of the on-off valves. Flow in the order of the valve, the second outdoor heat exchanger, or the first side path, the second outdoor heat exchanger, the auxiliary expansion valve, the first outdoor heat exchanger, the second side path, An air conditioner characterized in that one of the outdoor heat exchangers is used as a condenser and the other is used as an evaporator, and these are alternately switched so that defrosting can be performed during a heating operation. 2. The air conditioner according to claim 1, wherein the auxiliary expansion valve is constituted by an electronic expansion valve having a variable throttle amount. 3. The air conditioner according to claim 1, wherein a solenoid valve is used for each of said on-off valves. 4. When the first outdoor heat exchanger is frosted,
The expansion valve is fully opened, the auxiliary expansion valve is throttled to a predetermined amount, the first on-off valve and the third on-off valve are opened, and the second on-off valve and the fourth on-off valve are closed. The air conditioner according to claim 1, wherein: 5. When the second outdoor heat exchanger is frosted,
The expansion valve is fully opened, the auxiliary expansion valve is throttled to a predetermined amount, the second on-off valve and the fourth on-off valve are opened, and the first and third on-off valves are closed. The air conditioner according to claim 1, wherein: