JPH02106671A - Air conditioner - Google Patents

Abstract

PURPOSE:To shorten a changing-over time than that of the prior art, keep a longer heating operation time and improve a comfortable air conditioning by a method wherein a changing of compression capability is instantaneously got through a stopping and a starting of a second compressor having a designated compressing capability, and a compressing capability required in case of changing-over between a heating and a defrosting operation is changed together with the varying operation. CONSTITUTION:A unit 1 is constructed such that a first compressor 31 whose number of revolutions can be changed under a control of inverter and a second compressor 32 whose number of revolution is constant are connected in parallel to each other and stored in a housing. Temperature of an outdoor heat exchanger 7 is detected, an outdoor control device 40 is operated and a total output frequency is reduced. That is, the second compressor 32 is stopped, and after a reduction corresponding to a frequency of an applied power supply for the second compressor is carried out, if necessary, an output frequency for the first compressor 31 is gradually reduced to get a total frequency (fo) in case of performing a predetermined changing-over operation. As a result of such a control, a reduction of compressing capability at the second compressor 32 is carried out substantially instantaneously, so that change of capacity is carried out within a short period of time, resulting in that a high pressure reaches rapidly a low pressure state in case of performing a predetermined changing- over operation.

Description

Detailed Description of the Invention (Industrial Application Field) This invention has a compressor with variable compression capacity, and also has a function to switch to a defrosting operation to remove frost generated on an outdoor heat exchanger during a heating operation. It is related to air conditioners.

(Prior Art) As a conventional example of the above-mentioned air conditioner, there can be mentioned, for example, a device described in Japanese Patent Application Laid-open No. 59-185955. The device connects the discharge piping and suction piping of a variable rotation speed compressor controlled by an inverter to a four-way switching valve, and further connects the four-way switching valve with an indoor heat exchanger, a pressure reducing mechanism,
A refrigerant circulation circuit is constructed by sequentially connecting outdoor heat exchangers.

In the above device, the refrigerant discharged from the compressor is circulated from the indoor heat exchanger side to the outdoor heat exchanger to perform heating operation, and the defrosting operation is to remove frost that has formed on the outdoor heat exchanger during this heating operation.
From the above, the four-way selector valve is switched to circulate the refrigerant discharged from the compressor from the outdoor heat exchanger to the indoor heat exchanger, which is what is called reverse cycle defrosting.

When switching from heating operation to defrosting operation, the rotation speed of the compressor is reduced from the rotation speed corresponding to the indoor heating load during heating operation to a predetermined low rotation speed, and in this state four-way switching is performed. After switching the valve, control is performed to increase the rotation speed to a predetermined defrosting speed.

This is because when the compressor is rotating at high speed, that is, when operating at high compression capacity, there is a large difference between the discharge pressure and suction pressure, and when the four-way selector valve is switched in this state, the refrigerant flow path changes. This is because shock vibrations are generated when the room is closed, causing discomfort to the occupants. When returning to heating operation after defrosting, the compressor is similarly placed in a low compression capacity state and the four-way selector valve is switched to prevent impact vibrations.

(Problem to be Solved by the Invention) However, in the above device, the compression capacity is changed when switching between heating and defrosting by gradually reducing the inverter control frequency to a predetermined low rotational speed state, and then gradually increasing the frequency to achieve a predetermined low rotational speed state. Since it is necessary to change the operating frequency to the operating frequency during frost (when defrosting starts) or the operating frequency during heating (when heating resumes), the switching time becomes longer due to the time of gradual decrease and increase. Heating capacity decreases due to shorter heating operation time,
This poses a problem in that sufficient comfort cannot be obtained.

This invention was made in view of the above, and its purpose is to shorten the switching time between heating operation and defrosting operation as described above, thereby extending the heating operation time than before and making air conditioning more comfortable. The purpose of the present invention is to provide an air conditioner that can improve performance.

(Means for Solving the Problems) Therefore, in the air conditioner of the present invention, the compressor unit 1 includes:
A refrigerant circulation path during heating in which the discharged refrigerant is circulated from the indoor heat exchanger 15 to the outdoor heat exchanger 7 and returned to the compressor unit 1, and the discharged refrigerant is supplied to the outdoor heat exchanger 7. After that, a refrigerant circuit that provides a refrigerant circulation path during defrosting that is returned to the compressor unit l is connected, and the refrigerant circuit is switched between a refrigerant circulation path during heating and a refrigerant circulation path during defrosting. An air conditioner equipped with a switching means 17, 18, 23, in which the compressor unit 1 is connected to a first compressor 31 having a variable compression capacity and a second compressor 32 having a constant compression capacity to each other. In addition, when the switching means 17, 18, and 23 are switched in a predetermined low compression capacity state to switch between heating and defrosting, the compression capacity during heating and defrosting is switching operation control means 40 for changing compression and force between the low compression capacity state and the low compression capacity state by stopping and restarting the second compressor 32 in combination with changing the compression capacity of the first compressor 31; It is set up.

(Function) In the air conditioner having the above configuration, the pressure m capacity required when switching between heating and defrosting can be changed by stopping and starting the second compressor 32, which has a constant compression capacity. 32
First, the compression capacity bone is changed instantaneously, and only for the amount of change exceeding the compression capacity of the second compressor 32, an additional change may be made in the first compression [31] of the variable compression capacity type.
Therefore, the switching time is shortened by the amount of time required for changing the compression capacity of the second compressor 32 in the past.

This makes it possible to secure a longer heating operation time, thereby improving air conditioning comfort.

(Example) Next, regarding a specific example of the air conditioner of this invention,
This will be explained in detail with reference to the drawings.

FIG. 1 shows a refrigerant circuit diagram of an apparatus according to an embodiment of the present invention, which is configured as a multi-type air conditioner by connecting the first to fourth indoor units A to D to one outdoor unit X. ing.

A compressor unit 1 is installed inside the outdoor unit Further, a first gas pipe 5 and a second gas pipe 6 are connected. The compressor unit 1 is constructed by connecting a first compressor 31 whose rotation speed is variable by inverter control and a second compressor 32 whose rotation speed is constant and housing them in a housing. Also, the first and second compressors 31
．． Each suction side of 32 is connected to a first accumulator 33.
．． They are interconnected via 33.

An outdoor heat exchanger 7 is connected to the first gas pipe 5, and a first electric expansion valve 8 and a liquid receiver 9 are connected to the outdoor heat exchanger 7.
Further, a liquid pipe 10 is connected thereto. The tip of this liquid pipe 10 is connected to a second electric expansion valve 11, respectively.
11 are interposed, and the tip of the second gas pipe 6 is also branched into four liquid receiving pipes 12...12, each having a gas branch pipe muffler 13...13 interposed therein. It is branched into four gas branch pipes 14...14.

And these liquid receiving pipes 12...12 and gas branch pipes 14...
14, each indoor heat exchanger 15 (only the first indoor unit A is shown) installed in the first to fourth indoor units A to D is connected to form a refrigerant circulation circuit. .

A discharge pipe muffler 16 and a first on-off valve 1 are connected to the discharge pipe 2 in the refrigerant circulation circuit from the compressor unit 1 side.
7 are successively interposed, and the discharge pipe muffler 16
A first bypass pipe 19 in which a second on-off valve 18 is interposed is branched from between the first on-off valve 17 and the first electric expansion valve 8 in the liquid pipe 10.
It is connected to the outdoor heat exchanger 7 side.

Further, in the above device, a heat storage tank 21 is provided in the middle of the discharge piping 2, and the external heat storage tank 21 is maintained in a high temperature state by the flow of the high temperature discharged gas refrigerant from the compressor unit 1. The amount of heat dissipated is transferred to the heat storage tank 2.
Heat is stored in the heat storage agent filled in the inside of the tank. On the other hand, a second accumulator 2 is connected to the suction pipe 3.
2 is interposed, but the side of the suction pipe 3 closer to the four-way switching valve 4 than the first accumulator 22 and the first gas pipe 5 are connected to the third on-off valve 23. Second
A heat exchange section 25 is connected to the heat storage tank 21 by a bypass pipe 24 and is disposed in the middle of the second bypass pipe 24 on the side closer to the second accumulator 22 than the third on-off valve 23 . is provided so that the amount of heat stored in the heat storage agent is applied to the refrigerant flowing through the heat exchange section 25.

In the above-mentioned refrigerant circulation circuit, the discharge pipe 2 and the suction pipe 3 are connected to each other by a third bypass pipe 35 in which a fourth on-off valve 34 is interposed. This is to quickly equalize the pressure in the refrigerant circuit by opening the fourth on-off valve 34 after the first operation is stopped. Furthermore, in FIG. 1, the liquid receiving pipe 12 connected to the first indoor unit l-A is connected to the first bypass pipe 19 by the fourth bypass pipe 37 in which the fifth on-off valve 36 is interposed.
The gas branch pipe 14 to which the first indoor unit A is connected also has a sixth on-off valve 38 and a check valve 39.
For example, a parallel circuit is installed between the changing room of the bathroom when not in use and a drying unit for blowing hot air into the changing room. , which can be connected in place of the indoor unit A described above. In this case, other indoor units) B-
In order to perform refrigerant circulation control on the drying unit that is different from D, the opening and closing operations of the fifth and sixth on-off valves 3G and 38 described above will be performed, but the details will be omitted and the following will be described below. 1 indoor unit A is connected, therefore, the fifth on-off valve 36 is kept closed, the sixth on-off valve 38 is kept closed, and the fourth on-off valve 34 for pressure equalization is opened. Refrigerant circulation control with defrosting operation will be explained.

Although not shown in each indoor unit A-D above,
Each of them is further provided with an indoor control device, and the outdoor unit X is also provided with an outdoor control device 40 that also functions as a switching frame operation control means for heating operation and defrosting operation, as shown in the figure. . When the cooling/heating selector switch on the indoor control device side is set to the heating side and the operation switch is operated 0:1 by the user, the outdoor control device 40 moves the four-way selector valve 4 to the switching position shown by the solid line in the figure. Also, the first on-off valve 17 is opened, the second and third on-off valves 18 and 23 are closed, and the compressor unit 1 is activated to start heating operation. As a result, the refrigerant discharged from the compressor unit 1 is transferred to the four-step switching valve 4, the second gas pipe 6, as shown by the solid line arrow in the figure.
The liquid is supplied to each indoor heat exchanger 15 via the liquid pipe 10, passes through the outdoor heat exchanger 7, and is supplied to the compressor unit via the first gas pipe 5, four-way switching valve 4, and suction pipe 3. It is returned to 1. In this case, the degree of superheating of the evaporative refrigerant is controlled by the first electric expansion valve 8. In addition, each second electric expansion valve 11...1
1, the refrigerant distribution to each indoor heat exchanger 15 is controlled.
...This is done by controlling the opening degree of 11. The second electric expansion valve 11 corresponding to the indoor unit in the stop room is set to a predetermined stop opening (opening that allows a small amount of refrigerant to flow in proportion to natural heat dissipation in order to prevent liquid from returning to the compressor 1). ).

In the cooling operation, the four-way switching valve 4 is switched to the switching position shown by the broken line in the figure, and the refrigerant discharged from the compressor unit 1 is transferred to the outdoor heat exchanger that serves as the condenser, as shown by the broken line arrow in the figure. This is done by circulating the heat from the heat exchanger 7 to each indoor heat exchanger 15, which serves as an evaporator. At this time, the first electric expansion valve 8 is fully opened, and each of the second electric expansion valves 11 . . . 11 controls the degree of superheating of the refrigerant. Note that the second electric expansion valve 11 corresponding to the indoor unit in the room where cooling is stopped is fully opened.

If the frost that has grown on the outdoor heat exchanger 7 increases while the heating operation is continued, for example, the outdoor heat exchanger 7
Since the temperature of the outdoor heat exchanger 7 decreases with the amount of frost formed above, the temperature of the outdoor heat exchanger 7 is detected, and a defrost signal is generated when the detected temperature becomes below the reference temperature. In response to the defrost signal, the outdoor control device 40 controls the output frequency of the inverter control device (not shown) to the first compressor 31 for the compressor unit l as shown in FIG. , control for changing the total compression capacity by varying the total output frequency with the frequency of the commercial power supply (for example, 60 Hz) applied to the second compressor 32, each on-off valve 17, 18, 23, and four-way switching. valve 4
The opening/closing control of each electric expansion valve 8.11 and the opening degree control of each electric expansion valve 8.11 are performed. That is, the total output frequency is reduced substantially simultaneously with the generation of the defrost signal.

This is done by first stopping the second compressor 32 to reduce the frequency (60Hz) of the power applied to the second compressor, and then, if necessary, reducing the output frequency to the first compressor 31. The frequency is gradually decreased to a predetermined total switching frequency fo. As a result of such control, the compression capacity of the second compressor 32 is reduced compared to the compression capacity change time of a conventional device equipped with only a compressor with variable compression capacity, as shown by the broken line in the figure. Since this is done almost instantaneously, the capacity change can be made in a shorter period of time, and as shown in the column of high pressure side pressure in the figure, the high pressure side pressure can be changed more quickly to the low pressure state at the time of the predetermined switching. will be reached.

When this low pressure state occurs, the second on-off valve 18
and the third on-off valve 23 are opened, and then, after some delay, the first on-off valve 17 is closed, and the four-way switching valve 4 is switched to the switching position shown by the broken line in FIG. , second
The electric expansion valves 8 and 11 are respectively fully opened. Thereby, the refrigerant discharged from the compressor unit 1 is directly supplied to the outdoor heat exchanger 7 through the first bypass pipe 19, as indicated by the dashed-dotted arrow in FIG. The refrigerant that has passed through the outdoor heat exchanger 7 is changed into a refrigerant circulation cycle during defrosting, in which the refrigerant is returned from the first gas pipe 5 to the compressor unit 1 through the second bypass pipe 24.

After the above answer is switched, the total output frequency for the compressor unit 1 is increased to a predetermined defrosting operation frequency fd, but this is first performed by the second compressor 32 as shown in FIG.
This is done by restarting the compressor to give an increase of 60 Hz almost instantaneously, and then gradually increasing the output frequency to the first compressor 31. Therefore, in this case as well, the compression capacity can be changed more quickly and the pressure on the high pressure side can be increased more quickly than in the past, and the time required for these changes can be shortened.

In the refrigerant circulation cycle during the above-mentioned defrosting operation, the liquid refrigerant condensed by dissipating heat to the frosted, low-temperature outdoor heat exchanger 7 is returned to the compressor unit l through the second bypass pipe 24. In this case, the second bypass piping 2
The amount of heat stored in the heat storage tank 21 is provided in the heat exchange section 25 of No. 4. In other words, the amount of heat dissipated during the heating operation is stored in the heat storage tank 21, and the defrosting operation is performed in which this amount of stored heat is also utilized as the amount of defrosting heat. In addition, in the above case, at the start of defrosting operation, the indoor side is communicated with the suction pipe 3 via the four-way switching valve 4, and as a result, the refrigerant that had been supplied to each indoor side during the heating operation until then is were collected,
Thereby, the amount of heat stored in the refrigerant indoors at the start of the defrosting operation is utilized as the amount of heat for defrosting.

By continuing the defrosting operation described above, the frost adhering to the outdoor heat exchanger 7 is removed, and after that, when the temperature of the outdoor heat exchanger 7 rises and the detected temperature exceeds the predetermined defrost end temperature, the defrost operation starts. The signal is stopped, and as a result, the outdoor control device 40 performs an operation to return to the heating operation as shown in FIG. That is, substantially simultaneously with the stop of the defrost signal, the four-way switching valve 4 is switched and the first and second electric expansion valves 8.11 are opened. As a result, the indoor side, which had been communicating with the suction pipe 3 via the four-way switching valve 4, is cut off from communicating with the suction pipe 3, and high pressure is introduced from the liquid pipe 10 side. After that, compressor unit 1
The total output frequency of
After the first compressor 31 is stopped, the output frequency of the first compressor 31 is gradually decreased to shorten the change time.

Then, the high pressure side pressure is switched to a special low pressure state, the first on-off valve 17 is first opened, and the second and third on-off valves 18.23 are closed to return to the heating circulation cycle. Note that the compression capacity is increased after this return operation is completed by increasing the compression capacity of the first compressor 31 in stages to prevent oil from rising. I try to call 111.

As described above, in the above device, the change in compression capacity required when switching between heating and defrosting is performed in conjunction with stopping and starting the second compressor 32, thereby reducing the change time compared to conventional methods. As a result, the heating operation time can be secured for a longer period of time, thereby improving air conditioning comfort. In addition, in the above device, high-pressure refrigerant is introduced into the room from the liquid pipe 10 side when switching from defrosting operation to heating operation, but as a result, the high pressure rises quickly when heating is restarted, As a result, air-conditioning comfort is further improved by providing rapid heating.

Although specific embodiments of the present invention have been described above, the above embodiments do not limit the present invention, and various modifications can be made within the scope of the present invention.For example, in the above embodiment, heating and The switching means for defrosting is the first to third on-off valves 17.
．． 18.23 and is configured to defrost by so-called positive cycle defrost, in which the refrigerant discharged from the compressor unit 1 is directly supplied to the outdoor heat exchanger 7. The present invention can also be applied to a device that performs defrosting by reverse cycle defrosting like the conventional device described above, and in this case, the switching means between heating and defrosting is constituted by a four-way switching valve. Furthermore, although the above description has been given by way of example of a multi-type air conditioner in which a plurality of indoor units A to D are connected, the same implementation as described above is also possible in an air conditioner in which one indoor unit is connected.

(Effects of the Invention) As described above, in the air conditioner of the present invention, by stopping and starting the second compressor, which has a constant compression capacity, the compression capacity can be changed almost instantaneously. Since the compression capacity required when switching between heating and defrosting is changed, the switching time is shorter than before, and as a result, heating operation time can be secured longer, improving air conditioning comfort. .

[Brief explanation of drawings]

FIG. 1 is a refrigerant circuit diagram of an apparatus according to an embodiment of the present invention configured as a multi-type air conditioner, and FIG. 2 is a time chart of switching control to defrosting operation in the air conditioner. 1... Compressor unit, 7... Outdoor heat exchanger, 15
...Indoor heat exchanger, 17...First on-off valve, 18...
・Second on-off valve, 23...Third on-off valve, compressor, means) ・First compressor, ・Second pressure/outdoor control device (shaft movement control at switching

Claims (1)

[Claims] 1. Refrigerant during heating in which the discharged refrigerant of the compressor unit (1) circulates from the indoor heat exchanger (15) to the outdoor heat exchanger (7) and returns to the compressor unit (1). After the circulation path and the discharged refrigerant are supplied to the outdoor heat exchanger (7),
A refrigerant circuit providing a refrigerant circulation path during defrosting that is returned to the compressor unit (1) is connected, and the refrigerant circulation path during heating and a refrigerant circulation path during defrosting are switched to the refrigerant circuit. An air conditioner comprising switching means (17), (18), and (23), the compressor unit (1)
is constructed by connecting a first compressor (31) with a variable compression capacity and a second compressor (32) with a constant compression capacity in parallel, and in a predetermined low compression capacity state, the switching means (1)
7) When switching between heating and defrosting by switching (18) and (23), change the compression capacity between the compression capacity during heating and defrosting and the low compression capacity state described above. 2 compressors (
switching operation control means (4) for stopping and restarting the first compressor (32) in conjunction with changing the compression capacity of the first compressor (31);
0).