JP2001330347A - Air-conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that when frost adhered during heating operation is removed, heating capacity on the indoor side is rendered ineffective and an indoor temperature is lowered, in a conventional heat pump type air- conditioner. SOLUTION: This air-conditioner is constituted such that a bypass circuit extending through a two-way valve and a refrigerant flow rate regulating valve is provided between a branch from the refrigerant delivery side during heating and the inlet of an outdoor heat-exchanger and the bypass circuit extending through the two-way valve and the refrigerant flow rate regulating valve is provided between a branch from the refrigerant suction side and the two-way valve. This constitution enables to provide an air-conditioner having cycle constitution that the four-way valve is prevented from switching during defrosting and heating operation is practicable even during 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 for performing a cooling and heating operation using a heat pump.

[0002]

2. Description of the Related Art As a general air conditioner, an air conditioner in which an indoor unit installed indoors and an outdoor unit installed outdoors are connected by a refrigerant pipe is mainly used.

In this air conditioner, a compressor, a four-way valve, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are sequentially connected by pipes. In a cooling operation, a high-temperature air discharged from the compressor is used. The high-pressure refrigerant gas enters the outdoor heat exchanger in the outdoor unit and exchanges heat with the outside air by condensing. The normal-temperature and high-pressure refrigerant discharged from the outdoor heat exchanger becomes low-temperature and low-pressure liquid refrigerant by the decompressor, and flows into the indoor heat exchanger.
In the indoor heat exchanger, the liquid refrigerant evaporates and simultaneously absorbs indoor air temperature and discharges cooling air into the room.

On the other hand, in the heating operation, the high-temperature and high-pressure refrigerant gas discharged from the compressor flows into the indoor heat exchanger in the indoor unit, thereby exchanging heat with the indoor air and discharging the high-temperature air into the room. I do. The refrigerant from the indoor heat exchanger. The decompressor turns into a room-temperature, low-pressure liquid refrigerant and flows into the outdoor heat exchanger. In the outdoor heat exchanger, the refrigerant evaporates and exchanges heat with the outside air.

As described above, in the air conditioner, by switching the four-way valve, the circulation direction of the refrigerant is switched, and the cooling / heating operation is performed.

However, as described above, in the heating operation, the outdoor heat exchanger acts as an evaporator, so that dew in the outside air adheres to the outdoor heat exchanger as frost. Therefore, in the heating operation, if the defrosting operation is not performed periodically, frost grows and heat exchange with the outside air cannot be performed.

[0007] The defrosting operation of currently marketed air conditioners performs a temporary cooling operation and sends high-temperature and high-pressure refrigerant gas to an outdoor heat exchanger to melt frost.

As a conventional technique for performing such a defrosting operation, for example, JP-A-60-181556 is known.

[0009]

In the above prior art, the cooling operation is temporarily performed during the heating operation. Therefore, even if the indoor fan is stopped to prevent the cool air from being discharged into the room, the heating operation is temporarily performed. There is a problem that the room gets cold because it is temporarily interrupted.

In particular, in recent years, studies have been made to perform a heating operation using an air conditioner even in a cold region or a heavy snowfall region. In cold regions or heavy snowfall areas, the amount of frost increases,
It is clear that the frequency of defrosting increases and the heating effect decreases accordingly.

An object of the present invention is to provide an air conditioner capable of performing a defrosting operation while continuing a heating operation.

[0012]

An object of the present invention is to provide an air conditioner in which a compressor, a refrigerant flow converter, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant pipe. A first bypass circuit connecting the outdoor heat exchanger,
This is achieved by including a second bypass circuit that connects the indoor heat exchanger and the compressor.

[0013] In the air conditioner in which a compressor, a refrigerant flow converter, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant pipe, the compressor and the outdoor heat exchanger are connected. A first bypass circuit, a second bypass circuit that connects the indoor heat exchanger and the compressor, a first valve that opens and closes a refrigerant flow path of the first bypass circuit, And a second valve for opening and closing the refrigerant flow path of the bypass circuit.

Further, in an air conditioner in which a compressor, a refrigerant flow converter, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant pipe, the compressor and the outdoor heat exchanger are connected. This is achieved by providing a first bypass circuit, a second bypass circuit connecting the indoor heat exchanger and the compressor, and providing a refrigerant flow control valve in the first and second bypass circuits. You.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a refrigeration cycle diagram provided with the present invention. FIG. 2 is a block diagram for explaining the control of the freezing cycle.

In FIG. 1, reference numeral 1 denotes a refrigeration cycle including an indoor unit and an outdoor unit of an air conditioner. Reference numeral 2 denotes a compressor, which is a scroll compressor or a rotary compressor. Reference numeral 3 denotes a four-way valve for switching the direction of circulation of the refrigerant in accordance with a cooling operation or a heating operation command requested by the user (in this embodiment, a state in which the operation is switched to the heating operation). 4 is an indoor side heat exchanger. The indoor heat exchanger 4 is divided into two or three in consideration of the dehumidifying operation. 5 is a two-way valve. Reference numeral 6 denotes an expansion device that changes the amount of expansion according to the cooling and heating operation modes. The expansion device 6 is formed by an electric expansion valve. 7 is an outdoor heat exchanger. This heat exchanger 7 acts as an evaporator in the heating operation.

Reference numeral 8 denotes a first bypass pipe, which connects the compressor 2 and the four-way valve 3 to the outdoor heat exchanger 7. 9 is a two-way valve provided in the middle of the first bypass pipe 8. Reference numeral 10 denotes a refrigerant flow control valve provided in the middle of the first bypass pipe 8. Reference numeral 11 denotes a refrigerant return pipe connecting the four-way valve 3 and the compressor 2. Reference numeral 12 denotes an accumulator provided in the middle of the refrigerant return pipe 11. Reference numeral 13 denotes a second bypass pipe for returning the refrigerant from the indoor heat exchanger 4 to the return refrigerant pipe 11. The second bypass pipe 13 has a two-way valve 14 and a refrigerant flow control valve 15
Is connected. 16 is a fan for the outdoor heat exchanger 7. 17 is a fan for the indoor heat exchanger 4.

The heating operation and the defrosting operation by the refrigeration cycle of the present invention will be described.

First, a normal heating operation is indicated by refrigerant flow A.
The high-temperature and high-pressure refrigerant gas compressed by the compressor 2 flows to the indoor heat exchanger 4 by the four-way valve 3 and radiates heat. Due to this heat release, the refrigerant becomes a liquid refrigerant at normal temperature and low pressure, and the two-way valve 5 is opened, so that the pressure is reduced through the electric expansion valve 6, the heat is absorbed in the outdoor heat exchanger 7, and the refrigerant is evaporated. It again becomes refrigerant gas. The refrigerant that has become the refrigerant gas returns to the compressor 1 through the four-way valve 3. The heating operation is performed by repeating this series of operations.

During the heating operation, if the outside air temperature decreases and frost adheres to the outdoor heat exchanger 7, a defrosting operation is performed. This defrosting operation will be described with reference to the refrigerant flow B.

A part of the high-temperature and high-pressure refrigerant gas discharged from the compressor 2 flows into a first bypass circuit 8 connected between the compressor 2 and the four-way valve 3. This bypass circuit 8 is provided with a two-way valve 9 and a refrigerant flow control valve 10, but since the two-way valve 9 is open, the high-temperature and high-pressure refrigerant gas flows in the direction of the outdoor heat exchanger 7. move on. At this time, the two-way valve 5
Is closed, the refrigerant flows into the outdoor heat exchanger 7 and is warmed, and the frost is melted. At this time, the outdoor fan 16
Has stopped and there is no supply of outside air. Outdoor heat exchanger 7
Passes through the four-way valve 3 and returns to the compressor 2.

On the other hand, the high-temperature and high-pressure refrigerant gas flowing to the indoor heat exchanger 4 through the four-way valve 3 flows to the indoor heat exchanger 3 and radiates heat, as shown by a refrigerant flow B, and the indoor fan 17 Hot air is discharged into the room. Since the two-way valve 5 is closed, the normal-temperature and high-pressure liquid refrigerant flowing out of the indoor heat exchanger 4 flows in the direction of the second bypass circuit 13 and passes through the opened two-way valve 14, and then returns to the four-way valve 14. Return to the compressor 2 via the valve 3.

By the way, the first and second bypass circuits 8,
The refrigerant flow control valve 10 provided at 13 is for flowing the refrigerant gas in an optimal amount, and is for shortening the defrosting time.

In the defrosting operation by the refrigeration cycle 1, since the indoor heat exchanger 4 and the outdoor heat exchanger 7 become condensers, the amount of the liquid refrigerant returning to the accumulator 12 increases. As a countermeasure, the rotation of the indoor fan 17 may be reduced in speed and the amount of liquid refrigerant may be reduced by reducing the amount of heat released from the indoor heat exchanger 4 by reducing the air flow.

The liquid refrigerant condensed in the indoor heat exchanger 4 passes through the refrigerant flow control valve 15, so that the amount of liquid returned to the accumulator 12 can be made appropriate.

As described above, since the return amount of the liquid refrigerant can be made appropriate, breakage of valves and the like in the compressor 2 can be prevented, and the compressor has excellent reliability.

FIG. 2 illustrates the control of the refrigeration cycle according to this embodiment.

In FIG. 2, reference numeral 100 denotes a commercial AC power supply. The power supply 100 is connected to an indoor control unit 102. The power supply line D is connected to the indoor control unit 102 with respect to the outdoor control unit 103. An information line E is provided between the indoor control unit 102 and the outdoor control unit 103.
(Signal line). This power line D,
The information line E controls various operations between the indoor and outdoor units.

The indoor control unit 100 includes a driving operation unit 10
4, an indoor temperature sensor 105, a temperature sensor 106 for detecting the temperature of the indoor heat exchanger 4, a display unit 107, and an indoor fan motor 108 are connected.

The outdoor control unit 103 includes an outdoor temperature sensor 1
09, an outdoor fan motor 110, and a temperature sensor 111 for detecting the temperature of the outdoor heat exchanger 7 are connected. Also,
To control the defrosting operation, the outdoor heat exchanger 103 is connected with the four-way valve 3, the two-way valves 5, 9, 14, the electric expansion valve 6, and the outdoor fan motor 110.

The heating operation by this control will be described. In the heating operation, the indoor fan motor 108, the compressor 2, and the outdoor fan motor 110 are operated. Throttle the electric expansion valve 6,
When the two-way valve 5 is opened and the two-way valves 9 and 14 are closed, a normal heating cycle is configured, and the indoor heat exchanger 4 can function as a heating operation.

In the defrosting operation, it is confirmed that the difference between the outdoor temperature detected by the outdoor temperature sensor 109 and the temperature of the outdoor heat exchanger 7 detected by the heat exchange temperature sensor 111 is a predetermined temperature. Then, it is determined that frost is growing, and a defrosting operation command is issued to the outdoor control unit 103.

The outdoor control unit 103 includes the indoor fan motor 1
08, the compressor 2 is operated, the outdoor fan motor 110 is stopped, the two-way valve 5 is closed, and the two-way valves 9, 14 are opened. Thereby, the refrigerant flowing out of the indoor heat exchanger 4 passes through the second bypass circuit 13 to form one simple heating cycle.

On the other hand, a part of the high-temperature and high-pressure refrigerant gas discharged from the compressor 2 flows into the outdoor heat exchanger 7 via the first bypass circuit 8, and the defrosting operation is performed.

As described above, according to the present invention, since the defrosting operation can be performed while the heating operation is continued, a decrease in the room temperature can be suppressed even when the defrosting operation is started.

[0036]

According to the present invention, an air conditioner capable of performing a defrosting operation while continuing a heating operation can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle provided with the present invention.

FIG. 2 is a block diagram illustrating control of an air conditioner equipped with the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Refrigeration cycle, 2 ... Compressor, 3 ... Four-way valve, 4 ... Indoor heat exchanger, 5 ... Two-way valve, 6 ... Electric expansion valve, 7 ... Outdoor heat exchanger, 8 ... First bypass circuit, 9 ... two-way valve, 10 ... refrigerant flow control valve, 11 ... refrigerant return pipe, 12 ... accumulator, 13 ... second bypass circuit, 14 ... two-way valve, 15
... refrigerant flow control valve, 16 ... outdoor fan, 17 ... indoor fan.

Claims (3)

[Claims] 1. An air conditioner in which a compressor, a refrigerant flow converter, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant pipe, wherein the compressor and the outdoor heat exchanger are connected. An air conditioner comprising: a first bypass circuit; and a second bypass circuit connecting the indoor heat exchanger and the compressor. 2. An air conditioner in which a compressor, a refrigerant flow converter, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant pipe, wherein the compressor and the outdoor heat exchanger are connected. A first bypass circuit, a second bypass circuit that connects the indoor heat exchanger and the compressor, a first valve that opens and closes a refrigerant flow path of the first bypass circuit, And a second valve for opening and closing the refrigerant flow path of the bypass circuit. 3. An air conditioner in which a compressor, a refrigerant flow converter, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant pipe, wherein the compressor and the outdoor heat exchanger are connected. An air conditioner comprising: a first bypass circuit; a second bypass circuit connecting the indoor heat exchanger and the compressor; and a refrigerant flow control valve provided in the first and second bypass circuits.