JP3851201B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for suppressing pipe vibration during a reverse cycle defrosting operation.
[0002]
[Prior art]
Generally, a compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve, an indoor heat exchanger, and an indoor expansion valve are provided, and the refrigerant discharged from the compressor is switched to a reverse position during heating operation. A reverse cycle defrosting operation that flows through the outdoor heat exchanger in a cycle opposite to the heating operation cycle is performed, and this reverse cycle defrosting operation is performed by stopping the fan of the indoor heat exchanger and the indoor heat exchanger. 2. Description of the Related Art An air conditioner including a windy defrosting operation by operating a fan of an exchanger is known.
[0003]
FIG. 3 is a conventional timing chart of the reverse cycle defrosting operation.
[0004]
During the heating operation, the compressor is driven, the four-way valve is switched to the heating position, the outdoor electric valve is controlled according to the heating load, and the indoor electric valve is controlled to be fully opened. On the other hand, when the defrosting operation is necessary, the compressor is stopped for one minute prior to that, and the outdoor motor-operated valve is fully closed. After one minute, the compressor is driven, and at the same time, the four-way valve is switched to the reverse position, the outdoor motor-operated valve is fully opened, the indoor motor-operated valve is controlled to about half-open, and the reverse cycle defrosting operation is performed. .
[0005]
After the completion of this defrosting operation, the compressor is stopped for 1 minute, and both the outdoor motor-operated valve and the indoor motor-operated valve are controlled to be fully closed. Thereafter, the compressor is driven, the four-way valve is switched to the heating position, the outdoor motor-operated valve is controlled in accordance with the heating load, the indoor motor-operated valve is fully opened, and the original heating operation is restored.
[0006]
[Problems to be solved by the invention]
However, in the conventional configuration, after the defrosting operation is stopped, the outdoor motor-operated valve and the indoor motor-operated valve are fully closed, so the high / low pressure in the piping cannot be balanced, and the heating operation is resumed from this state. When the compressor is started, there is a problem that a shock is generated in the pipe and a large pipe vibration is generated.
[0007]
The reverse cycle defrosting operation may include a windless defrosting operation in which the fan of the indoor heat exchanger is stopped and a windy defrosting operation in which the fan of the indoor heat exchanger is operated. In this case, there is a problem that the time for balancing the high and low pressures in the pipe, that is, the time for the one minute varies depending on which defrosting operation is performed.
[0008]
Accordingly, an object of the present invention is to provide an air conditioner that solves the problems of the conventional techniques described above and can suppress the occurrence of pipe vibration due to the start of the compressor when returning to the heating operation. is there.
[0009]
[Means for Solving the Problems]
The invention according to claim 1 is the reverse cycle defrosting operation in which the four-way valve is switched to the reverse position during the heating operation, and the refrigerant discharged from the compressor is caused to flow to the outdoor heat exchanger in a cycle opposite to the heating operation cycle. And the reverse cycle defrosting operation includes an airless defrosting operation in which the fan of the indoor heat exchanger is stopped and a windy defrosting operation in which the fan of the indoor heat exchanger is operated. Then, after the reverse cycle defrosting operation is finished, the four-way valve is returned to the heating position after the elapse of this time with means for stopping the operation of the compressor while keeping the four-way valve in the reverse position. It is characterized by comprising means for starting the compressor and returning to the original heating operation, and means for changing the predetermined time according to a windless defrosting operation or a windy defrosting operation.
[0010]
The invention according to claim 2 includes a compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve, an indoor motorized valve, and an indoor heat exchanger, and the four-way valve is switched to a reverse position during heating operation. A reverse cycle defrosting operation is performed in which the discharged refrigerant flows through the outdoor heat exchanger in a cycle opposite to the heating operation cycle, and this reverse cycle defrosting operation removes no wind by stopping the fan of the indoor heat exchanger. In an air conditioner having a frost operation and a wind-driven defrost operation by operating a fan of an indoor heat exchanger, after the reverse cycle defrost operation is finished, the four-way valve remains in the reverse position for a predetermined time, A means for stopping the operation of the compressor, a means for returning the four-way valve to the heating position after this time has elapsed, starting the compressor to return to the original heating operation, and a windless defrosting operation or wind removal Means for changing the predetermined time according to the frost operation. Characterized in that was.
[0011]
According to a third aspect of the present invention, in the first or second aspect, after a predetermined time has elapsed, the four-way valve is returned to the heating position, and the compressor is started after a time interval to return to the original heating operation. A means for returning is provided.
[0012]
The invention according to claim 4 is the one according to claim 2 or 3, further comprising means for keeping the outdoor expansion valve fully open during the reverse cycle defrosting operation until returning to the original heating operation. Features.
[0013]
According to a fifth aspect of the present invention, in the one according to any one of the second to fourth aspects, the indoor expansion valve is maintained substantially half-open during the period from reverse cycle defrosting operation to returning to the original heating operation. Means are provided.
[0014]
The invention described in claim 6 is characterized in that, in the apparatus according to any one of claims 1 to 5, the windy defrosting operation is characterized in that the fan has a light wind speed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0016]
In FIG. 1, reference numeral 1 denotes a compressor, and an outdoor heat exchanger 5 is connected to the compressor 1 via a four-way valve 3. A receiver tank 7 is connected to the outdoor heat exchanger 5 via an outdoor electric expansion valve (hereinafter referred to as an outdoor electric valve) 6, and a heat storage tank electric valve 11 and a subcool valve are connected to the receiver tank 7 via a conduit 9. 13, a check valve 14 and an indoor electric expansion valve (hereinafter referred to as an electric valve) 15 are connected. The electric valve 15 is connected to an indoor heat exchanger 19 of the indoor unit 17 via a pipe line 20. The indoor heat exchanger 19 of the indoor unit 17 is connected to the four-way valve 3 via a pipe line 20, and the accumulator 21 and the compressor 1 are connected to the four-way valve 3.
[0017]
In the present air conditioner, a pipe line 22 is connected so as to bypass the above-described subcool valve 13, check valve 14, electric valve 15, and indoor unit 17, and a heat storage coil 23 and a two-way valve 24 are connected to the pipe line 22. Is connected. The heat storage coil 23 described above is installed in the heat storage tank 25 in a submerged state.
[0018]
The receiver tank 7 is connected to a pipe line 22 that connects the heat storage coil 23 and the two-way valve 24 via a pipe line 28 having an ice-breaking valve 26 and a check valve 27, and the receiver tank 7 is a liquid line. It is connected to a pipeline 9 that connects the check valve 14 and the motor operated valve 15 via a pipeline 30 having a valve 29. A conduit 32 having a liquid valve 31 and a capillary tube 32 is connected between the outdoor motor operated valve 6 and the receiver tank 7, and this conduit 32 is connected to the suction of the compressor 21.
[0019]
During the ice making operation, the four-way valve 3 is switched to the solid line position, and the refrigerant discharged from the compressor 1 flows in the order of the four-way valve 3, the outdoor heat exchanger 5, and the outdoor motorized valve 6, and enters the receiver tank 7. It flows into the heat storage coil 23 in the heat storage tank 25 through the path 9, the heat storage tank electric valve 11, and the pipe line 22 and evaporates here to make ice in the heat storage tank 25. The two-way valve 24, the four-way valve 3, and the accumulator 21 is returned to the compressor 1.
[0020]
During the normal cooling operation, the four-way valve 3 is switched to the solid line position, and the refrigerant discharged from the compressor 1 flows in the order of the four-way valve 3, the outdoor heat exchanger 5, and the outdoor electric valve 6, and enters the receiver tank 7. It reaches the pipe line 30 and the liquid line valve 29, and further flows into the indoor heat exchanger 19 of the indoor unit 17 via the motor operated valve 15, where it evaporates and vaporizes, and the pipe line 20, the four-way valve 3, and the accumulator 21 are connected. After that, it is returned to the compressor 1.
[0021]
During the heat storage cooling operation, the four-way valve 3 is switched to the solid line position, and the refrigerant discharged from the compressor 1 flows in the order of the four-way valve 3, the outdoor heat exchanger 5, and the outdoor electric valve 6 into the receiver tank 7, and from here It flows into the heat storage coil 23 in the heat storage tank 25 through the pipe line 28, the ice-breaking valve 26, and the check valve 27, and is cooled here to obtain cold heat from the ice. The pipe line 22, the subcool valve 13, and the check valve 14, and further flows through the motor-operated valve 15 into the indoor heat exchanger 19 of the indoor unit 17, where it evaporates and vaporizes, and returns to the compressor 1 through the conduit 20, the four-way valve 3, and the accumulator 21. It is.
[0022]
During the heating operation, the four-way valve 3 is switched to the broken line position, and the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 19 of the indoor unit 17 through the four-way valve 3 and condenses here. It enters the receiver tank 7 through the valve 15 and the liquid line valve 29, and flows from here through the outdoor electric valve 6 into the outdoor heat exchanger 5, where it evaporates and vaporizes, and then passes through the four-way valve 3 and the accumulator 21. Returned to the compressor 1.
[0023]
Next, the defrosting operation will be described.
[0024]
When frost formation on the outdoor heat exchanger 5 is detected during the heating operation, the four-way valve 3 is switched to the reverse position (solid line position), and the refrigerant discharged from the compressor 1 is changed to the above-described heating operation cycle. Flows along the reverse cycle (cooling operation cycle), so-called hot gas flows into the outdoor heat exchanger 5, and the outdoor heat exchanger 5 is defrosted. That is, it is a reverse cycle defrosting operation.
[0025]
In this embodiment, the reverse cycle defrosting operation includes a windless defrosting operation in which the fan 19A of the indoor heat exchanger 19 is stopped, and a light wind defrosting operation in which the fan 19A of the indoor heat exchanger 19 is operated in a slight wind. It is configured with. When the defrosting operation is finished in a short time, the light wind defrosting operation is selected. However, in the light breeze defrosting operation, the cold air is blown out into the conditioned room, so that the room temperature decreases. When it is not desired to lower the room temperature, the windless defrosting operation is selected.
[0026]
FIG. 2 is a timing chart of the windless defrosting operation in which the fan 19A of the indoor heat exchanger 19 is stopped in the reverse cycle defrosting operation.
[0027]
During the heating operation, the compressor 1 is driven, the four-way valve 3 is switched to the heating position A (the broken line position in FIG. 1), the outdoor electric valve 6 is controlled according to the heating load, and the indoor electric valve 15 is substantially omitted. It is controlled by half-open B (intermediate opening).
[0028]
When the defrosting operation is required, the compressor 1 is stopped while the four-way valve 3 remains in the heating position A for 1 minute prior to that. In this case, the outdoor motor-operated valve 6 and the indoor motor-operated valve 15 are fully opened C and D. After 1 minute, the compressor 1 is driven, and at the same time, the four-way valve 3 is switched to the reverse position E, the outdoor motor-operated valve 6 remains fully open C, and the indoor motor-operated valve 15 is controlled to about half-open F. A cycle defrosting operation is performed.
[0029]
After the defrosting operation is completed, the compressor 1 is stopped for 80 seconds while the four-way valve 3 is in the reverse position E, the outdoor electric valve 6 is fully open C, and the indoor electric valve 15 is approximately half open F. After 80 seconds have passed, the outdoor motor-operated valve 6 is fully open C, the indoor motor-operated valve 15 remains approximately half-opened F, the four-way valve 3 is switched to the heating position A, and then the compressor is separated by a time interval of 10 seconds. 1 is activated to return to the original heating operation.
[0030]
By the way, the four-way valve 3 has a structure that cannot be switched unless a certain pressure difference occurs between high and low pressures in the pipe. Therefore, if the 80 seconds for stopping the compressor 1 is set too long, the high and low pressures in the piping balance and the four-way valve 3 cannot be switched. Therefore, while there is a slight high-low pressure difference in the pipe, that is, before the high and low pressure in the pipe is almost completely balanced, the four-way valve 3 is first switched, and then the high and low pressure in the pipe is almost completely balanced. After that, the compressor 1 was started to return to the original heating operation.
[0031]
In the present embodiment, the 80-second stop time of the compressor 1 described above is changed depending on whether the reverse cycle defrosting operation is a windless defrosting operation or a light wind defrosting operation. That is, in the windless defrosting operation, the stop time of the compressor 1 is set to 80 seconds, but in the light wind defrosting operation, the time is changed to 60 seconds. In this light wind defrosting operation, the high and low pressures in the pipes are balanced in a relatively short time compared to the windless defrosting operation. Therefore, if the stop time of the compressor 1 is set to 80 seconds, the switching of the four-way valve 3 is hindered. Because there is a fear of coming.
[0032]
In the above configuration, when the compressor 1 is started, the four-way valve 3 has already been switched, and since there is almost no high / low pressure difference in the pipe, no shock is generated when the compressor 1 is started, and vibration of the pipe does not occur. It was greatly suppressed. By the way, even after the high and low pressures in the pipes are almost completely balanced, if the compressor 1 is started and the four-way valve 3 is switched at the same time, a liquid hammer is generated in the pipes, resulting in large pipe vibrations. It has been found to occur.
[0033]
In FIG. 2, since the outdoor motor-operated valve 6 is maintained at the fully open C and the indoor motor-operated valve 15 is maintained at the substantially half-open F until the return to the original heating operation from the reverse cycle defrosting operation (90 seconds). Compared to the case where each valve is controlled to be fully closed as in the prior art, a balance between high and low pressures can be achieved in a short time.
[0034]
In addition, since the outdoor motor-operated valve 6 is maintained in the fully open C until the transition from the heating operation to the reverse cycle defrosting operation (for 1 minute), compared to the case where the valve is controlled to be fully closed as in the past, High and low pressure can be balanced efficiently. Therefore, the shock at the time of starting the compressor 1 at the time of transfer to reverse cycle defrost operation is reduced, and piping vibration can be suppressed.
[0035]
As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this.
[0036]
【The invention's effect】
In the present invention, at the time of starting the compressor when returning to the heating operation, the four-way valve is already switched, and the difference between high and low pressures in the pipe is small, so there is little shock due to the liquid hammer, and pipe vibration is greatly suppressed.
[Brief description of the drawings]
FIG. 1 is a refrigerant circuit diagram showing an embodiment of an air conditioner according to the present invention.
FIG. 2 is a timing chart of a reverse cycle defrosting operation.
FIG. 3 is a timing chart of a conventional reverse cycle defrosting operation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Compressor 3 Four-way valve 5 Outdoor heat exchanger 6 Outdoor electric expansion valve 15 Indoor electric expansion valve 19 Indoor heat exchanger

Claims (6)

During the heating operation, the four-way valve is switched to the reverse position, and the reverse cycle defrosting operation is performed in which the refrigerant discharged from the compressor flows to the outdoor heat exchanger in a cycle opposite to the heating operation cycle. In an air conditioner, the operation includes a windless defrosting operation in which the fan of the indoor heat exchanger is stopped, and a windy defrosting operation in which the fan of the indoor heat exchanger is operated,
After the reverse cycle defrosting operation is completed, the compressor is stopped for a predetermined time while the four-way valve is in the reverse position, and after this time has elapsed, the four-way valve is returned to the heating position, and the compressor An air conditioner comprising: means for starting and returning to the original heating operation; and means for changing the predetermined time according to a windless defrosting operation or a windy defrosting operation. It is equipped with a compressor, four-way valve, outdoor heat exchanger, outdoor expansion valve, indoor motorized valve, and indoor heat exchanger. The four-way valve is switched to the reverse position during heating operation, and the refrigerant discharged from the compressor is heated. A reverse cycle defrosting operation that flows through the outdoor heat exchanger in a cycle opposite to the cycle is performed, and this reverse cycle defrosting operation includes a non-wind defrosting operation with the indoor heat exchanger fan stopped, and an indoor heat exchanger. In an air conditioner equipped with windy defrosting operation by operating a fan of
After the reverse cycle defrosting operation is completed, the compressor is stopped for a predetermined time while the four-way valve is in the reverse position, and after this time has elapsed, the four-way valve is returned to the heating position, and the compressor An air conditioner comprising: means for starting and returning to the original heating operation; and means for changing the predetermined time according to a windless defrosting operation or a windy defrosting operation. The apparatus according to claim 1 or 2, further comprising means for returning the four-way valve to the heating position after a predetermined time has elapsed, starting the compressor at a time interval, and returning to the original heating operation. Air conditioner. The air conditioner according to claim 2 or 3, further comprising means for keeping the outdoor expansion valve fully open during the period from the reverse cycle defrosting operation to the return to the original heating operation. The air conditioning according to any one of claims 2 to 4, further comprising means for maintaining the indoor expansion valve substantially half-opened during the period from the reverse cycle defrosting operation to the return to the original heating operation. apparatus. The air conditioner according to any one of claims 1 to 5, wherein in the windy defrosting operation, a fan has a light wind speed.

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