JPH01179874A - Air-conditioner - Google Patents

Abstract

PURPOSE:To permit defrosting with a simple constitution, by the constitution wherein the excessive amount of refrigerant upon effecting defrosting operation is stored in any one of a plurality of indoor heat exchangers while gas refrigerant, discharged out of a compressor, is supplied to an outdoor heat exchanger directly through the other indoor heat exchangers. CONSTITUTION:When gas refrigerant, discharged out of a compressor 1 and supplied to respective indoor heat exchangers 15, 16, passes through the specified indoor heat exchanger 15 upon defrosting operation effected by a defrosting operation control unit 31, an indoor fan 21, provided in the specified indoor heat exchanger 15, is stopped. Accordingly, the gas refrigerant is not condensed and pressure reducing effect is not applied in a motor-driven expansion valve 17, whose opening degree is controlled so as to be opened fully, and the gas is supplied to an outdoor heat exchanger 8 directly through a liquid pipe 9. On the other hand, the gas refrigerant, discharged out of the compressor 1 and supplied to the other indoor heat exchanger 16, is condensed in the indoor heat exchanger 16 and stored in the same since the opening degree of the other motor-driven expansion valve 18 is controlled to the side of a small opening degree. The gas refrigerant is supplied to the heat exchanger 8 in such a manner, whereby defrosting may be effected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an air conditioner, and particularly to an air conditioner having a function of switching to defrosting operation.

(Prior art) For example, in a separate air conditioner, the frost that adheres to the outdoor heat exchanger that acts as an evaporator during heating operation is removed (
Defrosting methods include the so-called reverse cycle defrosting method, in which the refrigerant circulation direction is switched from the indoor heat exchanger side to the outdoor heat exchanger during heating to the opposite direction, and the other is the reverse cycle defrosting method, which is performed by switching the refrigerant circulation direction from the indoor heat exchanger side to the outdoor heat exchanger side during heating. There is a so-called positive cycle defrost system in which the discharged gas refrigerant supplied from the air conditioner to the indoor heat exchanger is divided during defrosting and one part is directly supplied to the outdoor heat exchanger. This positive cycle defrost system has the advantage of being able to reduce the degree of indoor temperature drop, as well as producing less noise because it does not require switching the refrigerant circulation direction, that is, switching the four-way switching valve, and is therefore relatively frequently used. has been done. For example, as a conventional example, JP-A-59-21
An example of the device described in Japanese Patent No. 0269 can be mentioned, and the device will be explained based on FIG. 3.
Reference numeral 1 denotes a compressor, and the refrigerant discharged from the compressor 51 passes through a first gas pipe 52, a condenser 53, a liquid pipe 54, and an evaporator 55 in order, and is then sent to the compressor from a second gas pipe 56. machine 5
It is possible to circulate within the circuit where the flow is returned to the suction side of the pump. Note that 57 is an expansion valve installed in the liquid pipe 54, and 58 is an accumulator.

In the above device, the first gas pipe 52 and the liquid pipe 5
4, a bypass pipe 6 with an electromagnetic on-off valve 59 interposed therebetween.
0 is further connected to the evaporator 55 by opening the electromagnetic on-off valve 59 and introducing the gas refrigerant discharged from the compressor 51 directly into the evaporator 55 through the bypass pipe 60. defrosting is performed.

However, in recent years, multiple indoor units, each with a built-in indoor heat exchanger, are connected in parallel to a single outdoor unit with a built-in compressor, outdoor heat exchanger, etc., allowing simultaneous air conditioning operation in multiple rooms. Multi-type air conditioners have also been put into practical use, but even in such devices, devices that have a defrosting function using the positive cycle defrost method described above require a separate connection between each indoor heat exchanger and the outdoor heat exchanger. In addition to the refrigerant circulation circuit that connects the exchanger and compressor, a bypass pipe with an on-off valve as described above is provided, and the gas refrigerant discharged from the compressor is transferred to outdoor heat through this bypass pipe. It is designed to defrost by supplying it directly to the exchanger.

(Problems to be Solved by the Invention) As mentioned above, in order to perform defrosting operation using the positive cycle defrost method, it has conventionally been necessary to separately provide bypass piping through which refrigerant flows only during defrosting operation. In order to control the opening and closing of the electromagnetic on-off valve installed in the bypass piping, electrical control equipment such as a drive relay is required, which complicates the structure and increases the number of design and assembly steps. This poses a problem in that the production cost also increases.

This invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a simpler solution for the multi-type air conditioner in which multiple indoor units are connected to one outdoor unit. An object of the present invention is to provide an air conditioner that enables defrosting using the above-described positive cycle defrost method.

(Means for Solving the Problems) Therefore, in the air conditioner of the present invention, a first gas pipe 6 is connected to the discharge side of the compressor 1, and a second gas pipe 7 is connected to the suction side of the compressor 1. an outdoor heat exchanger 8 functioning as an evaporator;
A plurality of first gas branch pipes 13 and 14 branched from the tip of the first gas pipe 6 and the liquid pipe 9 are sequentially connected to each other.
branch from the tip of the electric expansion valve 17.1.
A refrigerant circulation circuit is constructed by connecting indoor heat exchangers 15 and 16 each functioning as a condenser between the plurality of liquid branch pipes 11 and 12 interposed in each of the indoor heat exchangers 15 and 15.
．． Each of the electric expansion valves 17.1 above according to the air conditioning load on the 16 side.
an operation control means 30 for controlling the operation by circulating the refrigerant discharged from the compressor 1 from the indoor heat exchanger 15, 16 side to the outdoor heat exchanger 8 while controlling the opening degree of the outdoor heat exchanger 8;
The air conditioner further comprises: stopping the indoor fan 21 attached to at least one specific indoor heat exchanger 15; and stopping the indoor fan 21 attached to the specific indoor heat exchanger 15; While controlling the opening of the expansion valve 17 to the full open side, controlling the opening of the electric expansion valve 18 connected to the indoor heat exchanger 16 other than the specific indoor heat exchanger 15 to the small opening side, and A defrosting operation in which one outdoor fan attached to the outdoor heat exchanger 8 is stopped and the refrigerant discharged from the compressor 1 is circulated from the distribution indoor heat exchanger 15 side to the outdoor heat exchanger 8. It has a control means 31.

(Function) In the above-mentioned air conditioner, during the defrosting operation by the defrosting operation control means 31, the gas refrigerant discharged from the compressor and supplied to each indoor heat exchanger 15, 16 has a specific indoor heat level. When passing through the exchanger 15, this indoor heat exchanger 15
Because the indoor fan 21 attached to the valve is stopped, no condensation occurs, and the electric expansion valve 17, whose opening is controlled to the fully open side, does not have a pressure reducing effect and directly flows into the liquid pipe 9. The heat is then supplied to the outdoor heat exchanger 8. On the other hand, the discharge gas refrigerant from the compressor 1 supplied to the indoor heat exchanger 16 other than the specified indoor heat exchanger 15 (hereinafter referred to as the other indoor heat exchanger) is Since the electric expansion valve 18 on the 16 side is controlled to have a small opening, the liquid condenses in the indoor heat exchanger 16 and accumulates in a liquid state. In other words, during steady operation by the operation control means 30 other than during defrosting operation, the pipe paths on the liquid pipe 9 side of each indoor heat exchanger 15, 16 and outdoor heat exchanger 8 are in a liquid phase state. The amount of refrigerant that has been circulating will be stored in the other indoor heat exchanger 16 as a surplus amount during the defrosting operation. As a result, the refrigerant can flow in a gas state also in the piping path of the nine liquid pipes between the specified indoor heat exchanger 15 and the outdoor heat exchanger 8, and therefore the gas refrigerant discharged from the compressor 1 can It is directly supplied to the outdoor heat exchanger 8 in a gaseous state from the liquid pipe 9 via the above-mentioned specific indoor heat exchanger 15. The frost adhering to the heat exchanger 8 will be defrosted. In addition to the refrigerant circulation circuit configured by connecting each indoor heat exchanger 15, 16, outdoor heat exchanger 8, and compressor a1, it is necessary to add, for example, bypass piping with a conventional on-off valve. It is possible to perform defrosting operation without having to do so, and it is possible to simplify the configuration.

(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 an example of a so-called multi-air conditioner in which one outdoor unit (X) is connected to two indoor units A and B, which are placed in rooms A and B, respectively.

In the figure, 1 is a compressor, and a discharge pipe 2 and a suction pipe 3 of the compressor 1 are each connected to a four-way switching valve 4, and an accumulator 5 is interposed in the suction pipe 3. ing. A first gas pipe 6 and a second gas pipe 7 are connected to the four-way switching valve 4, and an outdoor heat exchanger 8 is connected to the second gas pipe 7. This outdoor heat exchanger 8 functions as an evaporator during heating operation and as a condenser during cooling operation. Further, a liquid pipe 9 is further connected to the outdoor heat exchanger 8, and two liquid branch pipes 1 are branched from the tip of the liquid pipe 9.
1.12 and two first gas branch pipes 13.14 that are mutually branched from the tip of the first gas pipe 6, the indoor heat exchangers are respectively arranged in the indoor units A and B. 15 and 16 are connected in parallel with each other. Each of these indoor heat exchangers 15 and 16 functions as a condenser during heating operation and as an evaporator during cooling operation. Each of the liquid branch pipes 11.12 is provided with an electric expansion valve 17.18. In the same figure, 1
9 is an outdoor fan attached to the outdoor heat exchanger 8;
21.22 are each of the above indoor heat exchangers 15.1
This is an indoor fan attached to 6. Furthermore, inside the outdoor unit An outdoor control device 32 having
Each room is provided with an indoor control device (not shown) that issues a cooling or heating operation request signal to the outdoor control 2MII device.

In the above device B, the cooling/heating operation control section 30:
Indoor unit) Cooling or heating operation according to the operation requests from the A and B sides is performed as follows.

That is, when there is a request for cooling operation from the indoor side, the four-way switching valve 4 is placed in the switching position shown by the solid line in the figure, and the outdoor fan 19 and indoor fans 21 and 22 are started, respectively, and the compressor is switched on. Drive 1. As a result, the refrigerant discharged from the compressor 1 circulates as shown by the solid line in FIG.
．． At step 16, the air is evaporated and cooling operation is performed. In this case, by controlling the opening of each electric expansion valve 17, 18 to maintain the degree of superheating of the evaporative refrigerant at a predetermined value, cooling operation is performed in which the amount of refrigerant circulation is adjusted to match the indoor air conditioning load. will be held. Note that when each indoor unit A or B is in single-room operation without an operation request, the indoor fan on the side that is not in operation is stopped and the electric expansion valve is closed.

On the other hand, when there is a request for heating operation from the indoor side, 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 1 is changed to the position shown by the broken line in FIG. The cooling/heating operation control unit 30 performs an operation in which the heat is condensed in each of the indoor heat exchangers 15 and 16 and circulated in the direction of evaporation in the outdoor heat exchanger 8. At this time, each indoor unit
If there is no operation request in either A or B, it is assumed that there is no air conditioning load on that indoor unit, and the indoor fan on the side that is not operating is stopped, and the electric expansion valve is maintained at a small opening. be done. By maintaining a state in which a small amount of refrigerant can flow through this electric expansion valve, a rise in high pressure in the indoor heat exchanger on the stopped side is prevented.

When the outdoor heat exchanger 8 is frosted during the above-mentioned heating operation, the amount of frosting becomes large and, for example, the detected temperature of the outdoor heat exchanger 8 becomes lower than the preset defrosting start temperature. When detected, the heating operation control by the cooling/heating operation control section 30 is switched to the following defrosting operation by the defrosting operation control section 31.

First, the four-way switching valve 4 continues in the switching position state on the heating operation side. Then, the outdoor fan 19 is stopped, and at the same time, one of the indoor fans of the indoor unit AXB is stopped. In other words, if the previous heating operation had been in single room operation in only one room, the indoor fan on the side that was stopped at that time would remain stopped, and if the previous heating operation was in two rooms at the same time. In this case, the indoor fan in the indoor unit on the predetermined side is stopped. Now, if we describe the side where the indoor fan has stopped in this way as the indoor unit A, then the electric expansion valve 17 in the liquid branch pipe] 1 connected to this indoor unit A is changed from the controlled opening state corresponding to the air conditioning load. , or when the heating is stopped, the opening control is performed from the small opening state as described above to the full opening state. On the other hand, indoor fan 22
The electric expansion valve 18 in the liquid branch pipe 12 on the indoor unit B side, which continues to be driven, performs opening control to reduce the opening from the previously controlled opening commensurate with the air conditioning load to a small opening. By carrying out such control TFTl, the gas refrigerant discharged from the compressor 1 and branched from the first gas pipe 6 to each of the first gas branch pipes 13 and 14 is in the indoor heat exchanger 15 on the room A side. Since the indoor fan 21 is in a stopped state, there is almost no heat exchange with the indoor atmosphere, and therefore the liquid flows to the liquid branch pipe 11 in a gaseous state without condensing as occurs during heating operation. Furthermore, since the electric expansion valve 17 provided in the liquid branch pipe 11 is fully open, the gaseous refrigerant flows directly into the outdoor heat exchanger 8 without being subjected to any pressure reduction action. Although the refrigerant passes through the indoor heat exchanger 15 on the room A side, the refrigerant is circulated so that the discharged gas refrigerant from the compressor 1 is directly supplied to the outdoor heat exchanger 8. Similar to the positive cycle defrost, the compression work of the compressor l is transferred to the outdoor heat exchanger 8.
Defrosting will be carried out.

On the other hand, since the indoor fan 22 in the indoor unit B continues to be driven, the discharged gas refrigerant from the compressor 1, which is diverted to the first gas branch pipe 14 on the indoor unit B side, is disposed of in the indoor heat exchanger 16. To tank. However, since the electric expansion valve 18 of the liquid branch pipe 12 connected to this indoor heat exchanger 16 is kept in a small opening state, most of the liquid refrigerant compressed in the indoor heat exchanger 16 is transferred to the indoor heat exchanger 16. It will be stored in the heat exchanger 16. In other words, A
During the positive cycle defrosting period 1 to 1, in which the gas refrigerant is circulated through the piping paths on the liquid pipe 9 side of the indoor heat exchanger 15 and the outdoor heat exchanger 8, heating operation is performed with respect to the refrigerant circulation amount. At times, an amount approximately equivalent to the amount of liquid refrigerant flowing through the piping path on the liquid pipe 9 side becomes excessive, so this excess amount of refrigerant is stored in the indoor heat exchanger 16 on the side of room B,
As a result, the liquid branch pipe 11 and the liquid pipe 9 from the indoor heat exchanger 15 to the outdoor heat exchanger 8 can be used as gas pipes, for example, without separately providing a large-capacity accumulator.
This makes it possible to perform cycle defrosting.

While the liquid is being stored in the indoor heat exchanger 16 on the B room side, changes in the discharge pressure due to, for example, an increase in the amount of liquid stored or a decrease in the amount of refrigerant circulation are detected, which will be explained later. When the temperature drops below the predetermined value before the defrosting completion signal is issued, the indoor fan 22 on the indoor unit B side also stops. As a result, condensation in the indoor heat exchanger 16 is suppressed, and therefore, the amount of refrigerant circulation necessary for the positive cycle defrost via the indoor heat exchanger 15 on the room A side is ensured, and the defrosting of the outdoor heat exchanger 8 progresses. do. When defrosting is completed, for example, a signal indicating that the detected temperature of the outdoor heat exchanger 8 exceeds a predetermined defrosting completion temperature is sent to the defrosting operation control unit 31.
When this is input, the operation control is then switched to the cooling/heating operation control section 30, and the heating operation is restarted.

As explained above, in the above embodiment, the amount of refrigerant that becomes surplus during the defrosting operation is stored in one of the plurality of indoor units A and B, and is transferred through the other of the indoor units A and B. The defrosting operation is performed by directly supplying the discharged gas refrigerant from the compressor 1 to the outdoor heat exchanger 8, and there is no need for piping required just for the defrosting operation, such as conventional bypass piping. The configuration can be simplified, and as a result, the device can be made smaller and the manufacturing cost can be reduced, for example. In addition, in the above embodiment, surplus refrigerant is stored in the indoor unit, so when restarting heating operation after defrosting, for example, a large-capacity accumulation rake is separately interposed in the suction pipe 3 of the compressor 1. Compared to a configuration in which surplus refrigerant is stored in this accumulator, the amount of refrigerant circulated necessary for heating operation and the return to the circulating state can be achieved in a shorter time, and the heating speed when heating operation is resumed is also improved. be done.

Note that the above embodiments do not limit this invention, and various modifications can be made within the scope of this invention. For example, the above example describes a multi-type air conditioner that can air condition two rooms, but The present invention can be applied to air conditioners and other multi-type air conditioners in which an indoor unit and a hot water heating unit are connected in parallel.

Furthermore, in the configuration of the above embodiment, each first
Electromagnetic on-off valves 41 and 42 are interposed in each of the gas branch pipes 13 and 14, and for example, after a predetermined amount of liquid has been stored in the indoor heat exchanger 15 on the A room side, the indoor fan 21 on the A room side It is also possible to configure the electromagnetic on-off valve 41 to close together with the stop operation of the electromagnetic on-off valve 4.
After the valve closing operation 1, the entire amount of the gas refrigerant discharged from the compressor 1 is supplied to the outdoor heat exchanger 8, so that the heat loss on the indoor side is reduced and the defrosting time can be shortened.

Furthermore, in the above embodiment, in the defrosting operation during single-chamber operation, it was explained that the liquid was stored in the driver's cab, but it could be configured so that the liquid was stored in the stop chamber. is also possible. In addition, in the defrosting operation when two chambers are operated simultaneously, the explanation above is that the liquid reservoir is placed on a predetermined side. It is also possible to configure the liquid reservoir side to be the side where the difference between the room temperature desired by the user and the detected room temperature is large, and the indoor fan is not driven on the liquid reservoir side for a while after the defrosting operation starts. Since the hot air continues to be blown out, defrosting operation is performed with a smaller drop in room temperature, making it possible to further improve air conditioning comfort.

(Effects of the Invention) As described above, in the air conditioner of the present invention, the surplus refrigerant amount during defrosting operation is stored in one of the plurality of indoor heat exchangers, and the other indoor heat exchanger is Since defrosting operation is performed by directly supplying the discharged gas refrigerant from the compressor to the outdoor heat exchanger through the It becomes possible to simplify the process.

[Brief explanation of the drawing]

Fig. 1 is a refrigerant circuit diagram of an embodiment of the air conditioner of the present invention, Fig. 2 is a refrigerant circuit diagram of another embodiment of the air conditioner of the invention, and Fig. 3 is a refrigerant circuit diagram of a conventional example. be. DESCRIPTION OF SYMBOLS 1... Compressor, 6... First gas pipe, 7... Second gas pipe, 8... Outdoor heat exchanger (evaporator), 9... Liquid pipe, 11.12...・Liquid receiving pipe, 13.14...First gas branch pipe, 15.16...Indoor heat exchanger (condenser), 17
．． 18... Electric expansion valve, 19... Outdoor fan, 21
... Indoor fan, 30... Cooling/heating operation control section (operation control means), 31... Defrosting operation control section (defrosting operation control means).

Claims (1)

[Claims] 1. A first gas pipe (6) is connected to the discharge side of the compressor (1), and a second gas pipe (6) is connected to the suction side of the compressor (1).
7), an outdoor heat exchanger (8) functioning as an evaporator and a liquid pipe (9) are connected in sequence, and a plurality of first gas branch pipes (13) branched from the tip of the first gas pipe (6) ( 14) and
A plurality of liquid branch pipes (1) branch from the tip of the liquid pipe (9) and each have electric expansion valves (17, 18)
1) and (12), connect indoor heat exchangers (15) and (16), each of which functions as a condenser, to form a refrigerant circulation circuit. The refrigerant discharged from the compressor (1) is transferred from the indoor heat exchanger (15) (16) side to the indoor heat exchanger (15) (16) while controlling the opening degree of each electric expansion valve (17) (18) according to the air conditioning load. An air conditioner comprising an operation control means (30) for controlling operation by circulating air to an outdoor heat exchanger (8), the air conditioner further being attached to at least one specific indoor heat exchanger (15). At the same time, the electric expansion valve (21) connected to this particular indoor heat exchanger (15) is stopped.
17) to the full open side, while controlling the electric expansion valve (18) connected to the indoor heat exchanger (16) other than the specific indoor heat exchanger (15) to the small opening side. At the same time, the outdoor fan (19) attached to the outdoor heat exchanger (8) is stopped, and the refrigerant discharged from the compressor (1) is transferred from the indoor heat exchanger (15) side to the outdoor heat exchanger. Exchanger (
An air conditioner characterized in that it has a defrosting operation control means (31) for circulating air to the air conditioner (8).