JP2007285614A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner capable of conducting stable defrosting operation of an exterior of an outdoor unit while continuing heating operation. <P>SOLUTION: The air conditioner of this invention is equipped with a measuring means for measuring elapsed time from start of heating operation and conducts the defrosting operation for removing frost of an outdoor heat exchanger 5 while continuing the heating operation. As an extra defrosting operation time for extending a preset initial defrosting operation time for conducting the defrosting operation is determined depending on the elapsed time measured by the measuring means, defrosting operation time of the air conditioner can be extended in accordance with the heating operation time, it is possible to securely conduct the defrosting operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air conditioner that performs a defrosting operation for removing frost adhering to an outdoor heat exchanger while continuing a heating operation.

  Conventionally, this type of heat pump type air conditioner defrosting method is a method of performing a defrosting operation in a cooling operation cycle by stopping the heating operation and switching a four-way valve. That is, the frost adhering to the outdoor heat exchanger can be melted by flowing the high-temperature and high-pressure gas discharged from the compressor directly to the outdoor heat exchanger. And while adhering frost melt | dissolves, a defrost operation is complete | finished, it switches to heating operation again, and heating operation is continued.

  However, when the defrosting operation is performed in such a manner, the indoor heat exchanger becomes an evaporator, which causes a problem that the indoor temperature is lowered and a feeling of cold air is felt. For such a problem, there is a method of performing a defrosting operation while performing a heating operation (see, for example, Patent Document 1). Hereinafter, an air conditioner capable of performing a defrosting operation while performing a heating operation will be described with reference to FIG.

FIG. 7 is a configuration diagram of a refrigeration cycle of a conventional air conditioner. In FIG. 7, a conventional air conditioner includes a compressor 101, a four-way valve 102, an indoor heat exchanger 110, a decompressor 105, and an outdoor heat exchanger 103, which are sequentially connected in a ring shape with refrigerant piping, and a compressor 101. A first bypass circuit having a two-way valve 109a and a capillary tube 109b, and a suction side of the compressor 101 between the outdoor heat exchanger 103 and the decompressor 105. And a two-way valve 108 and a second bypass circuit having the refrigerant heater 104. A two-way valve 106 is provided between the suction side of the compressor 101 and the four-way valve 102, and a two-way valve 107 is provided between the outdoor heat exchanger 103 and the decompressor 105. In the air conditioner configured as described above, when performing the defrosting operation, the refrigerant heated by the refrigerant heater 104 passes through the compressor 101 and then flows through the indoor heat exchanger 110; The flow is branched into the flow through the outdoor heat exchanger 103 through the first bypass circuit, the flow of the branched refrigerant is merged immediately before the refrigerant heater 104, and the refrigerant is again heated by the refrigerant heater 104 and compressed. Inhaled into machine 101.
Japanese Patent Laid-Open No. 11-182994

  However, in the conventional configuration, when performing the defrosting operation, the two-way valve 109a is opened, and the refrigerant discharged from the compressor 101 flows between the outdoor heat exchanger 103 and the four-way valve 102. The two-way valve 106 is necessary so that the hot gas refrigerant to be defrosted does not flow to the suction side of the compressor 101. In order to reduce the pressure loss in the cooling and heating operation, the two-way valve 106 having a large diameter is provided. The outdoor heat exchanger 103 is not only a very expensive configuration but also has a configuration in which the two-way valve 108 is opened from the heat pump operation to the refrigerant heating operation to perform the defrosting operation. Since the refrigerant flow is reversed, the two-way valve 107 needs to be closed once before the defrosting operation, and the two-way valve 107 is required at the entrance of the outdoor heat exchanger 103. Therefore, the above-described conventional refrigeration cycle requires four two-way valves, resulting in a refrigeration cycle having a complicated and expensive configuration.

In addition, when the frost on the exterior of the outdoor unit in the outdoor heat exchanger is severe, the heating operation resumes even if the defrosting operation is completed and the outdoor heat exchanger still has unmelted snow and ice. There was a problem of being done.

  An object of the present invention is to solve the above-mentioned conventional problems, and to provide an air conditioner that can perform a stable defrosting operation of the exterior of an outdoor unit while continuing a heating operation.

  In order to solve the above-mentioned conventional problems, the air conditioner of the present invention is provided with measuring means for measuring the elapsed time since the heating operation is started, and the frost of the outdoor heat exchanger is removed while continuing the heating operation. In the air conditioner for performing the defrosting operation to be removed, the extended defrosting operation time for performing the defrosting operation by extending the preset initial defrosting operation time is determined according to the elapsed time measured by the measuring means. To do.

  As a result, the defrosting operation time of the air conditioner can be extended in accordance with the heating operation time, so that the defrosting operation can be performed reliably.

  The air conditioner of the present invention includes a refrigeration circuit in which a compressor, a four-way valve, an indoor heat exchanger, a first pressure reducing means, and an outdoor heat exchanger are sequentially connected in an annular manner with a refrigerant pipe, and conditioned air is blown into the room. Connecting the indoor blower, the measuring means for measuring the elapsed time from the start of the heating operation, the indoor heat exchanger / first pressure reducing means, and the four-way valve / outdoor heat exchanger. A first bypass circuit having two decompression means, a first two-way valve, and a refrigerant heating means, and a connection between the compressor and the indoor heat exchanger and between the first decompression means and the outdoor heat exchanger. In the air conditioner that includes a third pressure reducing unit and a second bypass circuit having a second two-way valve, and performs a defrosting operation to remove frost from the outdoor heat exchanger while continuing the heating operation, the measurement During the initial defrosting operation set in advance according to the elapsed time measured by the means It is characterized in that by extending determining the extension defrosting operation time for the defrosting operation of.

  As a result, the defrosting operation time of the air conditioner can be extended in accordance with the heating operation time, so that the defrosting operation of the exterior of the outdoor unit can be reliably performed, and two two-way valves are provided. Since only the configuration is used, the product cost can be reduced.

  An air conditioner capable of performing a stable defrosting operation on the exterior of an outdoor unit while continuing the heating operation can be provided.

  An air conditioner according to a first aspect of the present invention includes an air conditioner that includes a measuring unit that measures an elapsed time after the heating operation is started, and performs a defrosting operation that removes frost from the outdoor heat exchanger while continuing the heating operation. In the apparatus, the defrosting operation can be extended by determining the extended defrosting operation time for performing the defrosting operation by extending the preset initial defrosting operation time based on the elapsed time measured by the measuring means. Therefore, the frost adhering to the exterior of the outdoor unit can be reliably defrosted.

An air conditioner according to a second aspect of the present invention is a refrigeration circuit in which a compressor, a four-way valve, an indoor heat exchanger, a first pressure reducing means, and an outdoor heat exchanger are sequentially connected in an annular manner with a refrigerant pipe, and conditioned air is blown indoors Connecting the indoor blower, the measuring means for measuring the elapsed time from the start of the heating operation, the indoor heat exchanger / first pressure reducing means, and the four-way valve / outdoor heat exchanger. A first bypass circuit having two decompression means, a first two-way valve, and a refrigerant heating means, and a connection between the compressor and the indoor heat exchanger and between the first decompression means and the outdoor heat exchanger. In the air conditioner that includes a third pressure reducing unit and a second bypass circuit having a second two-way valve, and performs a defrosting operation to remove frost from the outdoor heat exchanger while continuing the heating operation, the measurement Initial defrosting operation time set in advance by elapsed time measured by means By determining the extended defrosting operation time for extending the defrosting operation, the first two-way valve of the first bypass circuit is opened, the refrigerant is heated by the refrigerant heating means, and the heated refrigerant is removed from the compressor. The defrosting operation can be performed while continuing the heating operation by opening the second two-way valve of the second bypass circuit and allowing the refrigerant to pass through the outdoor heat exchanger after a certain time from flowing to the suction side. In addition, since the defrosting operation can be performed by further extending the normal defrosting operation time, the defrosting can be surely performed, and since only two two-way valves are used, the product cost can be reduced. be able to.

  Further, since the defrosting operation is performed while heating is continued, there is no need to switch the four-way valve, and no refrigerant noise is generated when the four-way valve is switched.

  Further, since the four-way valve is not switched during defrosting, the pressure fluctuation is small and the oil fluctuation of the compressor is small, so that the compressor can be operated with high reliability.

  Even when the length of the connecting pipe is long, the defrosting circuit is outside the room, so that the compressor oil level in the defrosting operation by the pipe length does not decrease, and the compressor can be operated with high reliability.

  In addition, since a part of the whole refrigerant is used for defrosting, an extremely large amount of refrigerant does not flow through the refrigerant heating means of the first bypass circuit, so that it can be constituted by a compact refrigerant heating means.

  Further, even when the cooling operation is performed, high-temperature and high-pressure refrigerant gas does not stay in the refrigerant heating means, and condensation does not occur in the refrigerant heating means.

  In the air conditioner of the third invention, particularly in the first or second invention, by performing a heating operation by setting a limit value for the rotational speed of the indoor fan that blows into the room within the extended defrosting operation time, Reducing heat exchange in the indoor unit and using a relatively high-temperature refrigerant for defrosting operation prevents snow and ice from adhering to and covering the exterior of the outdoor unit. , Functionality and safety can be improved.

  The air conditioner according to a fourth aspect of the present invention is the air conditioner according to the second aspect of the invention, and further includes a fourth pressure reducing means between the compressor side end of the second bypass circuit and the indoor heat exchanger. Since the amount of refrigerant flowing through the indoor heat exchanger can be suppressed and the amount of refrigerant flowing to the second bypass circuit can be increased by changing the throttle amount of the fourth decompression means, the defrosting operation is surely performed. Therefore, it is possible to avoid the state where snow or ice adheres to or covers the exterior of the outdoor unit, and to improve functionality and safety.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a configuration diagram of an air-conditioning apparatus according to a first embodiment of the present invention. In FIG. 1, the air conditioner of the present invention includes an indoor unit 1 and an outdoor unit 2, and the indoor unit 1 blows conditioned air into the indoor heat exchanger 3 that exchanges heat between the refrigerant and the air. The outdoor unit 2 includes an outdoor unit heat exchanger 5 that exchanges heat between the refrigerant and the outside air, an outdoor unit 6 that blows air to the outdoor heat exchanger 5, and a refrigeration cycle in heating operation and cooling operation. The four-way valve 7 for changing the circuit, the compressor 8 for compressing the refrigerant, the decompressor 9 as the first decompression means, the decompressor 10 for the refrigerant heating as the second decompression means, and the first two A first bypass circuit having a two-way valve 11 which is a two-way valve and a refrigerant heater 12 which is a refrigerant heating means, and a defrosting decompressor 13 and a second two-way valve which are third decompression means. A second bypass circuit having a two-way valve 14 and an expansion valve 15 as a fourth pressure reducing means; That. An electromagnetic expansion valve may be used for the decompressor 9. Further, there is no problem even if the decompressors 10 and 13 use decompressors that can change the throttle amount. The indoor unit 1 and the outdoor unit 2 each have an indoor control unit (not shown) and an outdoor control unit (not shown), and have an operation time circuit (not shown) that is a measuring means. Usually, the operation time circuit is disposed in the indoor unit 1.

  FIG. 2 is a control block diagram of the air-conditioning apparatus according to the first embodiment of the present invention. In FIG. 2, the control unit of the air conditioner of the present invention includes an indoor control unit 21, an outdoor control unit 22, and an operation time circuit 23. The indoor control unit 21 includes an indoor fan operation unit 24 that operates the indoor fan 4 and a defrost start operation unit 25 that receives an instruction to start the defrost operation. The outdoor control unit 22 includes a defrosting start determining unit 26 that determines the start of defrosting, a compressor operating unit 27 that controls the compressor 8, a decompressor opening variable unit 28 that controls the decompressor 9, An outdoor fan operating unit 29 that controls the outdoor fan 6, a two-way valve opening / closing unit 30 of the first bypass circuit that opens and closes the two-way valve 11 of the first bypass circuit, and a two-way valve 14 of the second bypass circuit. A two-way valve opening / closing part 31 of the second bypass circuit for opening / closing the refrigerant, an expansion valve opening varying part 32 for controlling the expansion valve 15, a refrigerant heater operation stop part for controlling the refrigerant heater 12, and the four-way valve 7. And a four-way valve switching unit 34 for controlling the control. Further, the operation time circuit 24 counts the elapsed time at the same time when the heating operation is started, and transmits the elapsed time to the defrost start operation unit 25 when it is determined that the defrost start is started.

  FIG. 3 is a control flowchart of the air conditioner according to the first embodiment of the present invention, and FIG. 4 is a time lapse diagram of the control of the air conditioner according to the first embodiment of the present invention. The control flow of the air conditioning apparatus of the present invention will be described with reference to FIGS.

  First, simultaneously with the start of the heating operation, the operation time circuit 23 is operated, and the elapsed time from the start of the heating operation is started to be counted. And when defrost detection is detected in the defrost start judgment part 26, the elapsed time after the heating operation is started is received from the operation time circuit 23, and when the elapsed time is shorter than the preset value a, A normal defrosting operation is started, and after the defrosting operation is completed, the value of the operation time circuit 23 is cleared.

  However, when the elapsed time received from the operation time circuit 23 is longer than the preset value a, the normal defrosting operation is started, and the time is further extended to perform the extended defrosting operation. The longer the heating operation is, the longer the extension time is set. In the extended defrosting operation, a limit value is provided for the number of rotations of the indoor fan 4 and the indoor fan 4 is controlled so as not to exceed the limit value. The movement of each device in this case will be described with reference to FIG. In the present embodiment, the four-way valve 7 is not switched to continue the heating operation.

  As shown in FIG. 4, in step 1, a normal heating operation is performed.

  Next, when it is determined in step 2 that the defrosting operation is started, the two-way valve 11 of the first bypass circuit (hereinafter, the refrigerant heating two-way valve 11) is opened, and the refrigerant flows into the first bypass circuit. At the same time, the operation of the refrigerant heater 12 is turned on. Further, the opening of the decompressor 9 is reduced, and the number of revolutions of the indoor fan is slightly lowered to continue the heating operation.

  After a certain time from step 2, the process proceeds to step 3. In step 3, the two-way valve 14 of the second bypass circuit (hereinafter, the defrosting two-way valve 14) is opened, the refrigerant flows into the second bypass circuit, and at the same time, the rotational speed of the compressor is increased. Increase defrosting capacity. The outdoor blower 6 is stopped during the defrosting operation.

  When the normal defrosting operation in step 3 is completed, the routine proceeds to step 4. In step 4, the extended defrosting operation is started, and the rotation speed of the indoor blower 4 is reduced to the limit value to continue the heating operation. Then, when the defrosting operation is extended and completed for the time determined by the time measured by the operation time circuit 23, the process proceeds to step 5.

  In step 5, the rotational speed of the compressor 8 returns to the original state, the refrigerant heating two-way valve 11 and the defrosting two-way valve 14 are closed, the refrigerant heater 12 is turned off, and the decompressor 9 The opening degree, the outdoor fan 6, and the indoor fan 4 are controlled to perform the original heating operation.

  In the present embodiment, the operation frequency of the compressor 8 is changed as appropriate, but the heating operation may be continued with a constant speed compressor.

(Embodiment 2)
Since the configuration of the air-conditioning apparatus according to the second embodiment of the present invention is the same as that of the first embodiment, the same reference numerals as those of the first embodiment are given and description thereof is omitted.

  FIG. 5 is a control flowchart of the air conditioner according to the second embodiment of the present invention, and FIG. 6 is a time lapse diagram of the control of the air conditioner according to the second embodiment of the present invention. The control flow of the air conditioning apparatus of the present invention will be described with reference to FIGS.

  First, simultaneously with the start of the heating operation, the operation time circuit 23 is operated, and the elapsed time from the start of the heating operation is started to be counted. And when defrost detection is detected in the defrost start judgment part 26, the elapsed time after the heating operation is started is received from the operation time circuit 23, and when the elapsed time is shorter than the preset value a, A normal defrosting operation is started, and after the defrosting operation is completed, the value of the operation time circuit 23 is cleared.

  However, when the elapsed time received from the operation time circuit 23 is longer than the preset value a, the normal defrosting operation is started, and the time is further extended to perform the extended defrosting operation. In the extended defrosting operation, the amount of refrigerant flowing through the indoor heat exchanger 3 is reduced by reducing the opening of the expansion valve 15, and the amount of refrigerant flowing through the second bypass circuit is increased, thereby increasing the defrosting capability. Can do. The movement of each device in this case will be described with reference to FIG. In the present embodiment, the four-way valve 7 is not switched to continue the heating operation.

  As shown in FIG. 6, in step 1, a normal heating operation is performed.

  Next, when it is determined in step 2 that the defrosting operation is started, the two-way valve 11 of the first bypass circuit (hereinafter, the refrigerant heating two-way valve 11) is opened, and the refrigerant flows into the first bypass circuit. At the same time, the operation of the refrigerant heater 12 is turned on. Further, the opening of the decompressor 9 is reduced, and the number of revolutions of the indoor fan is slightly lowered to continue the heating operation.

  After a certain time from step 2, the process proceeds to step 3. In step 3, the two-way valve 14 of the second bypass circuit (hereinafter, the defrosting two-way valve 14) is opened, the refrigerant flows into the second bypass circuit, and at the same time, the rotational speed of the compressor is increased. Increase defrosting capacity. The outdoor blower 6 is stopped during the defrosting operation.

  When the normal defrosting operation in step 3 is completed, the routine proceeds to step 4. In Step 4, the extended defrosting operation is started and the heating operation is continued. Next, the opening degree of the expansion valve 15 is reduced from the defrosting start time, and the amount of refrigerant flowing through the indoor heat exchanger is reduced. Then, when the defrosting operation is extended and completed for the time determined by the time measured by the operation time circuit 23, the process proceeds to step 5.

  In step 5, the rotational speed of the compressor 8 returns to the original state, the refrigerant heating two-way valve 11 and the defrosting two-way valve 14 are closed, the refrigerant heater 12 is turned off, and the decompressor 9 The opening degree, the outdoor fan 6, and the indoor fan 4 are controlled to perform the original heating operation.

  In the present embodiment, the operation frequency of the compressor 8 is changed as appropriate, but the heating operation may be continued with a constant speed compressor.

  As described above, in the present invention, the defrosting operation can be performed reliably by further extending the normal defrosting operation time. In addition to the first and second embodiments, in the normal defrosting operation, the defrosting operation is performed using the first bypass circuit and the second bypass circuit, and in the extended defrosting operation, the four-way valve is used. Defrosting may be performed by switching to a cooling operation circuit. When performing such a defrost operation, since the high temperature gas discharged from a compressor flows into an outdoor heat exchanger as it is, an efficient defrost operation can be performed.

  The air conditioner according to the present invention can perform the defrosting operation while continuing the heating operation, and can perform the defrosting more reliably, so that the air conditioner particularly in a cold district where the outdoor temperature is very low. Applicable to equipment.

The block diagram of the air conditioning apparatus in the 1st Embodiment of this invention Control block diagram in the same embodiment Control flowchart in the embodiment Control time lapse diagram in the same embodiment Control flowchart in the second embodiment of the present invention Control time lapse diagram in the same embodiment Configuration diagram of conventional air conditioner

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Indoor unit 2 Outdoor unit 3 Indoor heat exchanger 4 Indoor blower 5 Outdoor heat exchanger 6 Outdoor blower 7 Four-way valve 8 Compressor 9 Decompressor (1st decompression means)
10 Pressure reducer (second pressure reducing means)
11 Two-way valve (first two-way valve)
12 Refrigerant heater 13 Pressure reducer (third pressure reducing means)
14 Two-way valve (second two-way valve)
15 Expansion valve (fourth decompression means)
21 indoor control unit 22 outdoor control unit 23 operation time circuit

Claims (4)

In the air conditioner for performing a defrosting operation for removing frost from the outdoor heat exchanger while continuing the heating operation, the measurement unit that measures the elapsed time since the heating operation was started, An air conditioner that determines an extended defrosting operation time for performing a defrosting operation by extending a preset initial defrosting operation time according to time. A compressor, a four-way valve, an indoor heat exchanger, a first decompression means, an refrigeration circuit that sequentially connects the outdoor heat exchanger in a ring shape with a refrigerant pipe, an indoor fan that blows conditioned air into the room, and heating operation are started. Measuring means for measuring the elapsed time since the second, the second heat reducing means and the first two-way connecting the indoor heat exchanger and the first pressure reducing means and the four-way valve and the outdoor heat exchanger A first bypass circuit having a valve and a refrigerant heating means; and a third pressure reducing means and a second two connecting the compressor and the indoor heat exchanger and the first pressure reducing means and the outdoor heat exchanger. And an air conditioner that performs a defrosting operation for removing frost from the outdoor heat exchanger while continuing the heating operation, and is preset according to the elapsed time measured by the measuring means. Extension of defrosting operation by extending the initial defrosting operation time An air conditioning apparatus and determines the defrosting operation time. 3. The air conditioner according to claim 1, wherein the heating operation is performed by setting a limit value for the number of rotations of the indoor blower that blows into the room during the extended defrosting operation time. And a fourth depressurizing means between the compressor side end of the second bypass circuit and the indoor heat exchanger, and the throttle amount of the fourth depressurizing means is changed during the extended defrosting operation time. The air conditioning apparatus according to claim 2.

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