JPH10141815A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten defrosting time by constituting a bypass circuit where an opening and closing valve which opens at defrosting time and closes at cooling and heating operation is connected in parallel with a capillary tube. SOLUTION: This air conditioner is controlled so that a refrigerant may flow to a capillary tube 4 by closing an opening and closing valve 7 at cooling and heating operation, and that the refrigerant may flow and circulate to the opening and closing valve 7, bypassing the capillary tube 4, by fully opening the opening and closing valve 7 at defrosting operation. A cooling cycle is such that a heat exchanger 3 on outdoor side becomes a condenser and a heat exchanger 6 on indoor side becomes an evaporator at defrosting operation. At this time, an electronic expansion valve 5 is opened fully, and also the opening and closing valve 7 is opened fully, and the refrigerant is made to bypass the capillary tube 4, whereby the throttling of the refrigerant is relieved more, and the quantity of circulating refrigerant can be increased. Hereby. the defrosting time of the heat exchanger 3 on outdoor side can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner capable of shortening a defrosting time.

[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.
And an outdoor heat exchanger having two paths (two paths) of refrigerant channels
3 ′, a capillary tube 4 ′ connected to each of the two refrigerant passages of the outdoor heat exchanger 3 ′, and an electronic expansion valve 5 ′,
An indoor heat exchanger 6 'is formed, and these are connected in a ring by a refrigerant pipe. The air conditioner includes an outdoor blower 8 controlled by an outdoor control unit (not shown), an indoor blower 9 controlled by an indoor control unit (not shown), and the like.

[0003] With the above configuration, in Fig. 2, solid arrows indicate the refrigerant flow direction during the cooling operation and the defrosting operation, and broken line arrows indicate the refrigerant flow direction during the heating operation. In the air conditioner described above, 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 flows through the indoor heat exchanger 6 ′ while the indoor blower 9
By exchanging heat with room air, heat is released into the room and condensed. The condensed and liquefied liquid refrigerant passes through an electronic expansion valve 5 'and is split into two capillary tubes 4' to be decompressed.
It becomes a low-temperature low-pressure gas-liquid two-phase, and is absorbed by the air sent by the outdoor blower 8 while flowing through the two-system refrigerant flow path of the outdoor heat exchanger 3 ′, and becomes a low-temperature low-pressure gas refrigerant.
Is returned to the compressor 1. During the cooling operation, the operation is the same as that of the heating except that the operation of the outdoor and indoor heat exchangers 3 ′ and 5 ′ is reversed by switching the four-way valve 2.

In general, when the outside air temperature is low and the humidity is high, when the heating operation is performed, frost is formed on the outdoor heat exchanger, and the heating capacity is reduced. In such a case, the flow of the refrigerant is changed by the four-way valve (cooling cycle), and the defrosting operation starts. When an electronic expansion valve is used as the throttle mechanism of the refrigeration cycle, the throttle of the electronic expansion valve is loosened to increase the refrigerant circulation amount in order to shorten the defrosting time during defrosting. However, when there are a plurality of refrigerant flow paths (paths) in the outdoor heat exchanger, a capillary tube is provided between the outdoor heat exchanger and the electronic expansion valve to improve the path balance. For this reason, even if the electronic expansion valve is fully opened during defrosting, it is somewhat narrowed by the capillary tube, so that there is a problem that the defrosting time cannot be sufficiently reduced.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides an air conditioner that can shorten the defrosting time in an outdoor heat exchanger having a plurality of refrigerant passages. The purpose is to provide.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises a compressor, a four-way valve, an outdoor heat exchanger, a capillary tube, an expansion valve, and an indoor heat exchanger. The refrigerant flow path of the outdoor heat exchanger is divided into a plurality of channels, and the capillary tubes are connected between the plurality of refrigerant flow paths and the expansion valve, respectively. In an air conditioner that forms a cycle, a bypass circuit that connects an on-off valve that opens during defrosting operation and closes during cooling and heating operations is configured in parallel with the capillary tube.

The on-off valve is constituted by an electromagnetic valve. Further, the on-off valve is constituted by an electronic expansion valve.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A compressor, a four-way valve, an outdoor heat exchanger, a capillary tube, an expansion valve, and an indoor heat exchanger are sequentially connected by refrigerant piping, and the outdoor heat exchange is performed. In the air conditioner formed by connecting the capillary tubes between the plurality of refrigerant flow paths and the expansion valve to form a refrigeration cycle, the refrigerant flow paths of the heat dissipating device are formed in parallel with the capillary tubes. By configuring a bypass circuit that connects an on-off valve that opens during the defrosting operation and closes during the cooling and heating operations, the air conditioner can shorten the defrosting time.

[0009]

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 the refrigerant discharged from the compressor 1 in accordance with a heating operation, a cooling operation, etc., 3 is an outdoor heat exchanger having two refrigerant paths (2 paths), and 4 is outdoor heat exchange. Capillary tubes respectively connected to two refrigerant flow paths of the heat exchanger 3, 5 is an electronic expansion valve, 6 is an indoor heat exchanger, 7
Is an on-off valve comprising an electromagnetic valve or an electronic expansion valve constituting a bypass circuit connected in parallel to each of the capillary tubes 4, and these are connected in a ring by a refrigerant pipe to form a refrigeration cycle, and perform cooling and defrosting operations. During the heating operation, the refrigerant circulates as indicated by the solid arrow, and during the heating operation, the refrigerant circulates as indicated by the dashed arrow. The air conditioner includes an outdoor blower 8 controlled by an outdoor control unit (not shown), an indoor blower 9 controlled by an indoor control unit (not shown), and the like.

[0010] Of the equipment constituting the air conditioner, the compressor 1, the four-way valve 2, the electronic expansion valve 5, and the on-off valve 7 are all mounted in the outdoor and indoor control units, not shown. The microcomputer is controlled by a control microcomputer. When the cooling and heating operations are performed, the on-off valve 7 is closed, the refrigerant flows into the capillary tube 4, and the defrosting operation is performed when the on-off valve 7 is fully opened. Is controlled to flow to the on-off valve 7 and to circulate.

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 6.
The heat is exchanged with the indoor air by the indoor blower 9 while flowing through the air, thereby releasing and condensing the heat into the room. The condensed and liquefied liquid refrigerant passes through the electronic expansion valve 5 and is split into two capillary tubes 4 and decompressed, forming a low-temperature low-pressure gas-liquid two-phase.
While flowing through the two refrigerant passages of the outdoor heat exchanger 3, the heat is absorbed by the air sent by the outdoor blower 8, becomes a low-temperature low-pressure gas refrigerant, and 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 in the case of heating except that the functions of the indoor heat exchangers 3 and 6 are reversed.

Next, during the defrosting operation, a so-called cooling cycle in which the outdoor heat exchanger 3 functions as a condenser and the indoor heat exchanger 6 functions as an evaporator, and the electronic expansion valve 5 is fully opened at this time. By fully opening the on-off valve 7 and allowing the refrigerant to bypass the capillary tube 4, the restriction of the refrigerant can be further loosened and the refrigerant circulation amount can be increased.

As described above, an air conditioner is provided in which the on-off valve 7 for bypassing the capillary tube 4 is provided, and the defrosting time of the outdoor heat exchanger 3 can be reduced by increasing the amount of circulating refrigerant. .

[0014]

As described above, according to the present invention, even when the electronic expansion valve and the capillary tube are used in combination, the on-off valve for bypassing the capillary tube is provided, and the on-off valve is fully opened during the defrosting operation, so that the refrigerant circulating amount is reduced. The air conditioner can reduce the defrosting time by increasing the air conditioner.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing an air conditioner according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Capillary tube 5 Electronic expansion valve 6 Indoor heat exchanger 7 On-off valve 8 Outdoor blower 9 Indoor blower

Claims (3)

[Claims] A compressor, a four-way valve, an outdoor heat exchanger, a capillary tube, an expansion valve, and an indoor heat exchanger are sequentially connected by refrigerant pipes, and the outdoor heat exchanger is connected to the compressor. In an air conditioner formed by forming a refrigeration cycle by connecting the capillary tubes between the plurality of refrigerant flow passages and the expansion valve while forming the refrigerant flow passages as a plurality of system passages, removing the refrigerant flow in parallel with the capillary tubes. Open during frost operation,
An air conditioner comprising a bypass circuit connected to an on-off valve that closes during cooling and heating operations. 2. The air conditioner according to claim 1, wherein the on-off valve is constituted by a solenoid valve. 3. The air conditioner according to claim 1, wherein said on-off valve is constituted by an electronic expansion valve.