JP2598550B2 - Air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multi-room heat pump air conditioner in which a plurality of indoor units are connected to one heat source unit.
In particular, the present invention relates to an air conditioner that can selectively perform cooling and heating for each indoor unit, and perform cooling in one indoor unit and heating in the other indoor unit simultaneously.

[Conventional technology]

Conventionally, a heat pump type air conditioner in which a plurality of indoor units are connected to one heat source unit with two pipes of a gas pipe and a liquid pipe to perform a cooling and heating operation is generally used. Or, they are all formed to perform cooling.

[Problems to be solved by the invention]

Since the conventional multi-room heat pump air conditioner is configured as described above, all indoor units operate only for cooling or heating, so heating is performed where cooling is required, or conversely, heating is performed. However, there is a problem that air conditioning is performed in a place where it is necessary.

In particular, when installed in a large-scale building, there is a particular problem because the load of air conditioning is significantly different between an interior unit and a perimeter unit, or a general office room and a computer room or the like where OA is used.

The present invention has been made in order to solve the above-described problems. A plurality of indoor units are connected to one heat source unit, and cooling / heating is selectively performed for each indoor unit, and one of the indoor units is selectively operated. The indoor unit can be cooled and the other indoor unit can be heated at the same time.When installed in a large-scale building, the interior and perimeter sections, or the general office and computer room, etc. It is an object of the present invention to provide a multi-chamber heat pump type air conditioner that can cope with a significantly different air conditioning load in each room.

[Means for solving the problem]

The present invention relates to one heat source unit including a compressor, a four-way switching valve, a heat source unit side heat exchanger, an accumulator, and the like, and a plurality of indoor units including an indoor side heat exchanger, a first flow control device, and the like. Are connected via first and second connection pipes, and one of the indoor-side heat exchangers of the plurality of indoor units is connected to the first heat exchanger.
The first flow control device is connected to the other of the indoor branch heat exchangers of the plurality of indoor units and the first branch portion that is switchably connected to the connection pipe or the second connection pipe. And a second branch connected to the second connection pipe via a second flow control device via the second flow control device, and further connected to the second branch portion via the second flow control device. The second branch and the first connection pipe are connected via a fourth flow control device, and the first branch, the second flow control device, and the fourth flow control device are connected to each other.
And a repeater incorporating the second branch unit is interposed between the heat source unit and the plurality of indoor units, and the first connection pipe is connected to the second connection pipe. A cooling valve configured to have a large diameter and provided with a switching valve between the first and second connection pipes of the heat source unit so that the first connection pipe can be switched to a low pressure and the second connection pipe can be switched to a high pressure. In the air conditioner that can be operated simultaneously, at the time of defrosting, the four-way switching valve is switched, the first branch is closed, the first flow control device is closed, and the second and fourth flow rates are set. The control device is opened.

[Operation] In the present invention, in the case of heating mainly in simultaneous cooling and heating operation, high-pressure gas refrigerant is introduced into each indoor unit to be heated from the heat source unit switching valve, the second connection pipe, and the first branch. After that, the refrigerant flows from the second branch to a part of the indoor unit which is about to be cooled, performs cooling, and flows from the first branch to the first connection pipe.
On the other hand, the remaining refrigerant passes through the fourth flow control device, merges with the refrigerant that has passed through the cooling indoor unit, flows into the first connection pipe, and returns to the heat source unit.

In the case of cooling mainly, a high-pressure gas is heat-exchanged in an arbitrary amount by a heat source unit to make a two-phase state, and the gaseous refrigerant separated from the heat source unit side switching valve and the second connection pipe is passed through the first branch. Introduce to the indoor unit that is going to heat and heat and
Flows into the branch. On the other hand, the remaining liquid refrigerant separated passes through the second flow control device, merges with the refrigerant that has passed through the indoor unit to be heated in the second branch, and flows into each indoor unit to be cooled. After cooling, the air is guided from the first branch to the heat-source-unit switching valve through the first connection pipe, and returns to the compressor again.

Furthermore, in the case of only the heating operation, the refrigerant is introduced into each indoor unit through the second connection pipe and the first branch from the heat source unit side switching valve, heated, and heated to the first connection pipe from the second branch. And returns to the heat source device side switching valve.

In the case of only the cooling operation, the refrigerant is introduced into each indoor unit through the second connection pipe and the second branch from the heat source unit side switching valve, cooled, and cooled to the first connection pipe from the first branch. And returns to the heat source device side switching valve.

Then, at the time of defrosting in the case of mainly heating and in the case of only heating operation in the simultaneous cooling and heating operation, the defrosting is performed by exchanging heat of the high-temperature and high-pressure gas with the heat source device, and the second connection pipe is connected by the heat source device side switching valve. Second flow control device, fourth
And returns to the heat source device side switching valve through the first connection pipe.

〔Example〕

 Hereinafter, embodiments of the present invention will be described.

FIG. 1 is an overall configuration diagram mainly showing a refrigerant of an air conditioner of one embodiment of the present invention. 2 to 4 show an operation state of the cooling / heating operation in the embodiment of FIG. 1, and FIG. 2 is an operation state diagram of only cooling or heating, and FIGS. 3 and 4. Fig. 3 shows the operation of simultaneous cooling and heating operation. Fig. 3 shows the main heating operation (when the heating operation capacity is larger than the cooling operation capacity), and Fig. 4 shows the main cooling operation (when the cooling operation capacity is larger than the heating operation capacity). It is a driving | operation operation state diagram shown. FIG. 5 is an operation state diagram at the time of the defrosting operation in the embodiment of FIG.

In this embodiment, a case where three indoor units are connected to one heat source unit will be described, but the same applies to a case where two or more indoor units are connected.

In FIG. 1, (A) is a heat source device, (B), (C),
(D) is an indoor unit connected in parallel to each other as described later, and has the same configuration. (E) shows a first branch, a second flow controller, a second branch, a gas-liquid separator, a heat exchanger, a third flow controller, and a fourth flow controller as described later. A built-in repeater.

(1) is a compressor, (2) is a four-way switching valve for switching the refrigerant flow direction of the heat source device, (3) is a heat source device side heat exchanger,
(4) is an accumulator, which is connected to the above devices (1) to (3) to constitute a heat source unit (A). (5) is the three indoor heat exchangers, (6) is the four-way switching valve (2) of the heat source unit (A)
First connecting pipe connecting the relay and the repeater (E), (6
b), (6c) and (6d) are indoor units (B) and
(C), (D) indoor heat exchanger (5) and repeater (E)
And a first connection pipe on the indoor unit side corresponding to the first connection pipe (6), and (7) a heat source unit side heat exchanger (3) of the heat source unit (A) and a relay unit (E). (7b), (7c) and (7d), which are smaller than the first connection pipe, connect the indoor heat exchangers (B), (C) and (D), respectively. 5) and the repeater (E) to connect the second connection pipe (7)
(8) is the first connection pipe (6a), (6b), (6c) of the indoor unit corresponding to the first connection pipe (6) or the second connection pipe. A switching valve branch of a first branch which is switchably connected to the side of the first connection pipe (7), and a first port which is a connection with the second connection pipe at an opening / closing valve (8a); A second port which is a connection portion with the connection pipe has an on-off valve (8b).

(9) The first control is performed by the superheat amount during cooling and the subcool amount during heating at the outlet side of the indoor heat exchanger (5) connected close to the indoor heat exchanger (5). The second connection pipe (7b), (7
c) Connected to (7d). (10) switchably connects the first connection pipes (6b), (6c) and (6d) on the indoor unit side to the first connection pipe (6) or the second connection pipe (7). The first branch portion composed of the switching valve portion (8) of the first branch portion, (11) is a second connection pipe (7) on the indoor unit side.
b), (7c), (7d) and a second connecting pipe
And (12) a gas-liquid separation device provided in the middle of the second connection pipe (7), and the gas phase portion thereof is connected to the first port of the switching valve (8) of the first branch portion. Connected to the on-off valve (8a)
The liquid phase is connected to the second branch (11).
(13) is an openable / closable second flow control device connected between the gas-liquid separation device (12) and the second branch portion (11), and (14) is the second branch portion (11) and the above-mentioned second flow control device. A bypass pipe connecting to the first connection pipe (6), (15) a third flow control device provided in the middle of the bypass pipe (14), (16b), (16c),
(16d) is the third flow control device (1) of the bypass pipe (14).
It is provided downstream of 5) and exchanges heat with the junction of the second connection pipes (7b), (7c), and (7d) on the indoor unit side in the second branch (11). A third heat exchange section,
(16a) is the third flow control device (1
5) that is provided downstream of the second branch (11) and exchanges heat with the junction of the second connection pipes (7b), (7c), and (7d) on the indoor unit side in the second branch (11). The second heat exchange unit (19) is provided downstream of the third flow control device (15) in the bypass pipe (14) and downstream of the second heat exchange unit (16a). A first heat exchange section for exchanging heat between the pipe connecting the second flow control device and the second flow control device; and (17) a second branch section (11) and the first connection pipe ( 6) A fourth flow control device which can be opened and closed and connected between the fourth flow control device.

(32) is a third check valve provided between the heat source unit side heat exchanger (3) and the second connection pipe (7), and is a third check valve. ) Is allowed to flow only to the second connection pipe (7). (33) is a fourth check valve provided between the four-way switching valve (2) of the heat source unit (A) and the first connection pipe (6). From 6), the refrigerant is allowed to flow only to the four-way switching valve (2). (34) is a fifth check valve provided between the four-way switching valve (2) of the heat source unit (A) and the second connection pipe (7), and is a fifth check valve (2). ) Is allowed to flow only to the second connection pipe (7).
(35) is a sixth check valve provided between the heat source unit side heat exchanger (3) and the first connection pipe (6), and is provided from the first connection pipe (6). Refrigerant circulation is allowed only to the heat source side heat exchanger (3). The third check valve (32) to the sixth check valve (35) constitute a switching valve (40).

An embodiment of the present invention thus configured will be described.

First, the case of only the cooling operation will be described with reference to FIG.

That is, as shown by the solid arrows in FIG. 2, the high-temperature and high-pressure refrigerant gas discharged from the compressor (1) passes through the four-way switching valve (2) and exchanges heat with the heat source device side heat exchanger (3). After being condensed, the third check valve (32), the second connection pipe (7), the gas-liquid separation device (12), the second flow control device (1
3), and further through the second branch portion (11), the second connection pipe (7b), (7c), (7d) on the indoor unit side, and the indoor units (B), (C), (D). The refrigerant flowing into each of the indoor units (B), (C), and (D) is supplied by the first flow control device (9) controlled by the amount of superheat at the outlet of each indoor heat exchanger (5). The pressure is reduced to a low pressure, heat exchanges with room air in the indoor heat exchanger (5), evaporates, gasifies and cools the room. The refrigerant in the gas state is supplied to the first connection pipes (6b), (6c),
(6d), passing through the first branch portion (10), the switching valve portion (8) of the first branch portion, the first connection pipe (6), the fourth check valve (33), the heat source device ( A circulation cycle is drawn into the compressor (1) through the four-way switching valve (2) and the accumulator (4) in A), and the cooling operation is performed. At this time, the first opening / closing valve (8a) of the switching valve section (8) is closed, and the second opening / closing valve (8b) is open. Also, at this time, since the first connection pipe (6) has a low pressure and the second connection pipe (7) has a high pressure, the third check valve (32) and the fourth check valve ( 33).

Furthermore, during this cycle, the second flow control device (1
Part of the refrigerant that has passed through 3) enters the bypass pipe (14) and is reduced to a low pressure by the third flow control device (15).
In the third heat exchange sections (16b), (16c) and (16d), between the second connection pipes (7b), (7c) and (7d) on the indoor unit side,
In the second heat exchange section (16a), between the second connection pipes (7b), (7c), and (7d) of the second branch section (11) on the side of each indoor unit, The refrigerant that has exchanged heat with the refrigerant flowing into the second flow control device (13) in the first heat exchange section (19) and evaporates is supplied to the first connection pipe (6) and the fourth check valve. (33)
And is sucked into the compressor (1) through the four-way switching valve (2) and the accumulator (4). On the other hand, the first, second and third heat exchange sections (19), (16a), (16b), (16c), (1)
The refrigerant in the second branch portion (11), which has been cooled by the heat exchange in 6d) and sufficiently attached to the subcooler, flows into the indoor units (B), (C), and (D) to be cooled.

Next, a case of only the heating operation will be described with reference to FIG. That is, as shown by a dotted arrow in FIG. 2, the high-temperature and high-pressure refrigerant gas discharged from the compressor (1) passes through the four-way switching valve (2), passes through the fifth check valve (34) and the second connection. After passing through the pipe (7) and the gas-liquid separator (12), the first branch (1
0), the switching valve section (8) of the first branch, and the first connection pipes (6b), (6c), and (6d) on the indoor unit side in the order of each indoor unit (B), (C). , (D), exchanges heat with room air to condense and liquefy, and heats the room. Then, the refrigerant in this liquid state is controlled by the subcool amount at the outlet of each indoor heat exchanger (5), and the first flow control device (9)
Through the second connection pipe (7b), (7c),
From (7d) flows into the second branch (11) and merges there and further through the fourth flow control device (17), where the first flow control device (9) or the fourth flow control device In (17), the pressure is reduced to a low pressure two-phase state. Then, the refrigerant decompressed to a low pressure passes through the first connection pipe (6), flows into the heat source unit side heat exchanger (3) from the sixth check valve (35), exchanges heat, and evaporates. A gas state is established, and a circulation cycle is drawn through the four-way switching valve (2) and the accumulator (4) to the compressor (1) to perform a heating operation. At this time, the open / close valve (8a) of the switching valve section (8) of the first branch section is open, and (8b)
Is closed. Also, at this time, the first connection pipe (6) has a low pressure and the second connection pipe (7) has a high pressure, so that the fifth check valve (34) and the sixth check valve ( Distribute to 35).

The case of heating mainly in simultaneous cooling and heating operation will be described with reference to FIG. Here, indoor units (B) and (C)
A case in which the unit is heating and one indoor unit (D) is going to cool will be described.

That is, as shown by the solid arrows in FIG. 3, the high-temperature and high-pressure refrigerant gas discharged from the compressor (1) is supplied to the four-way switching valve (2), the fifth check valve (34), and the second connection pipe (7). ), Is sent to the repeater (E), passes through the gas-liquid separator (12), and is divided into the first branch portion (10), the switching valve portion (8) of the first branch portion, and the indoor unit side. The first connection pipe (6b), (6
Follow the order of c), indoor unit (B) to be heated,
(C), heat exchanges with the indoor air in the indoor heat exchanger (5), condensed and liquefied, and heats the room. The refrigerant in the liquid state is controlled by the subcool amount at the outlet of each indoor heat exchanger (5), passes through the first flow control device (9) which is almost fully opened, and is slightly depressurized to the second branch. Department (1
1). Then, a part of the refrigerant passes through the second connection pipe (7d) on the indoor unit side, enters the indoor unit (D) to be cooled, and depends on the amount of superheat at the outlet of the indoor heat exchanger (5). After entering the controlled first flow control device (9) and being decompressed, it enters the indoor heat exchanger (5) to exchange heat and evaporate to a gaseous state to cool the room, and to perform the first branch. It flows into the first connection pipe (6) via the switching valve section (8) of the section.

On the other hand, the other refrigerant has a high pressure in the second connection pipe (7),
Through a fourth open / close flow control device (17) controlled by the intermediate pressure value of the branching portion (11), and with the refrigerant passing through the indoor unit (D) to be cooled, Through the first connection pipe (6), the sixth check valve (3) of the heat source unit (A)
5), it flows into the heat source unit side heat exchanger (3), exchanges heat and evaporates to a gaseous state. Then, the refrigerant constitutes a circulation cycle in which the refrigerant is sucked into the compressor (1) through the four-way switching valve (2) and the accumulator (4) of the heat source unit, and performs the heating main operation. At this time, the pressure difference between the evaporation pressure of the indoor-side heat exchanger (5) of the indoor unit (D) to be cooled and the evaporation pressure of the heat-source-unit-side heat exchanger (3) is increased by the thick first connection pipe (6). It becomes smaller to switch. At this time, the indoor unit (B),
Switching valve section (8) of the first branch section connected to (C)
The second opening / closing valve (8b) is closed, and the first opening / closing valve (8a)
Is open, the first opening / closing valve (8a) of the switching valve section (8) of the first branch connected to the indoor unit (D) is closed, and the second opening / closing valve (8b) is closed. It is open. further,
At this time, since the first connection pipe (6) has a low pressure and the second connection pipe (7) has a high pressure, the fifth check valve (3)
4), flowing to the sixth check valve (35).

In this cycle, a part of the liquid refrigerant is supplied to the second connection pipes (7b), (7c), and (7b) of each indoor unit of the second branch (11).
It enters the bypass pipe (14) from the junction of (7d), is decompressed to a low pressure by the third flow control device (15), and is cooled by the third heat exchange units (16b), (16c), and (16d) to each room. A second heat exchange section (16a) is provided between the second connection pipes (7b), (7c) and (7d) on the indoor unit side of the second branch section (11) on the indoor unit side. Heat is exchanged between the junctions of the connection pipes (7b), (7c) and (7d), and the evaporated refrigerant enters the first connection pipe (6) and the sixth refrigerant of the heat source device (A) Flows into the heat source device side heat exchanger (3), exchanges heat and evaporates to a gas state. Then, the refrigerant is sucked into the compressor (1) through the four-way switching valve (2) and the accumulator (4) of the heat source device (A). On the other hand, the second and third heat exchange sections (16a), (1
The refrigerant in the second branch portion (11), which has been cooled by heat exchange in (6b), (16c), and (16d) and sufficiently subcooled, flows into the indoor unit (D) to be cooled.

About the case of cooling mainly in simultaneous cooling and heating operation
This will be described with reference to the drawings. Here, indoor units (B), (C)
A case will be described in which two units are going to be cooled and one indoor unit (D) is going to heat.

That is, as shown by the solid arrows in FIG. 4, the high-temperature and high-pressure refrigerant gas discharged from the compressor (1) exchanges an arbitrary amount of heat in the heat source unit side heat exchanger (3) to become a two-phase high-temperature and high-pressure gas. , Through the third check valve (32) and the second connection pipe (7), to the gas-liquid separator (12) of the repeater (E). Here, the gaseous refrigerant and the liquid refrigerant are separated, and the separated gaseous refrigerant is supplied to the first branch section (10), the switching valve section (8) of the first branch section, and the first branch section (10) on the indoor unit side. Connection piping (6
The air flows into the indoor unit (D) to be heated according to the order of d), and is condensed and liquefied by exchanging heat with the indoor air in the indoor heat exchanger (5) to heat the room. Further, the pressure is slightly reduced through the first flow control device (9) which is controlled by the subcool amount at the outlet of the indoor heat exchanger (5) and is almost fully open, and flows into the second branch portion (11). On the other hand, the gas-liquid separator (1
The remaining liquid refrigerant separated in 2) is an openable / closable second flow control device (13) controlled by the high pressure of the second connection pipe (7) and the intermediate pressure value of the second branch (11). And flows into the second branch portion (11), and merges with the refrigerant that has passed through the indoor unit (D) to be heated. Then, the second branch portion (11), the second connection pipe (7b) on the indoor unit side, and (7
The air flows into the indoor units (B) and (C) in the order of c).
The refrigerant flowing into each of the indoor units (B) and (C) is decompressed to a low pressure by the first flow control device (9) controlled by the amount of superheat at the outlet of the indoor unit-side heat exchanger (5). It flows into the indoor heat exchanger (5), exchanges heat with indoor air, evaporates and gasifies, and cools the indoor. Further, the refrigerant in this gas state is supplied to the first connection pipe (6
b), (6c), the first connection pipe (6) passing through the switching valve section (8) of the first branch section, the first branch section (10), and the fourth connection pipe (6).
Of the compressor (1) through the check valve (33), the four-way switching valve (2) of the heat source unit (A), and the accumulator (4), and performs cooling-main operation. At this time, the second opening / closing valve (8b) of the switching valve section (8) of the first branch connected to the indoor units (B) and (C) is open, and the first opening / closing valve (8a). Is closed, the first opening / closing valve (8a) of the switching valve unit (8) of the first branch unit connected to the indoor unit (D) is open, and the second opening / closing valve (8b) is open. It is closed. At this time, since the first connection pipe (6) has a low pressure and the second connection pipe (7) has a high pressure, the refrigerant is inevitably the third connection pipe.
Flows through the check valve (32) and the fourth check valve (33).

Further, during this cycle, a part of the liquid refrigerant is supplied to the second connection pipes (7b), (7c), and (7c) of each indoor unit of the second branch (11).
It enters the bypass pipe (14) from the junction of (7d), is decompressed to a low pressure by the third flow control device (15), and is cooled by the third heat exchange units (16b), (16c), and (16d) to each room. A second heat exchange section (16a) is provided between the second connection pipes (7b), (7c) and (7d) on the indoor unit side of the second branch section (11) on the indoor unit side. Between the connection pipes (7b), (7c), and (7d), and between the first heat exchange section (19) and the refrigerant flowing into the second flow control device (13). The refrigerant that has undergone heat exchange and evaporates enters the first connection pipe (6), where the fourth check valve (33) of the heat source unit (A), the four-way switching valve (2) of the heat source unit (A), and the accumulator After passing through (4), it is sucked into the compressor (1). on the other hand,
The first, second, and third heat exchange sections (19), (16a), (16)
The refrigerant in the second branch portion (11), which has been cooled by the heat exchange in (b), (16c) and (16d) and sufficiently subcooled, flows into the indoor units (B) and (C) to be cooled. .

Next, the case of the defrosting operation of the above embodiment will be described with reference to FIG.

That is, as shown by the solid arrow in FIG. 5, the high-temperature and high-pressure refrigerant gas discharged from the compressor (1) radiates heat in the heat source unit side heat exchanger (3) and adheres to the heat source unit side heat exchanger. After cooling and condensing while melting the third check valve (3
2), the second connection pipe (7), the gas-liquid separation device (12), the second flow control device (13), and the fourth flow control device (17) in this order. ), And is sucked into the compressor (1) through the fourth check valve (33), the four-way switching valve (2) of the heat source unit (A), and the accumulator (4). At this time, since the first connection pipe (6) has a low pressure and the second connection pipe (7) has a high pressure, the third check valve (32) and the fourth
To the check valve (33).

At this time, the first opening / closing valve (8a) and the second opening / closing valve (8b) of the switching valve portion (8) of the first branch are both closed. Further, the first flow control devices (9) of all the indoor units are all closed. Thus, each indoor heat exchanger (5) and the first connection pipe (6
Since the refrigerant does not flow through b), (6c) and (6d), there is no feeling of cool air in the room and no freezing of the indoor unit due to a decrease in the indoor unit evaporation temperature. Also, the first connection pipes (6b), (6
c) and (6d) are not cooled by the refrigerant, so that the heating operation starts quickly after returning from the defrost operation.

 This will be described below with reference to FIGS. 6 and 7.

FIG. 6 is a configuration diagram of the control during the defrosting operation of the embodiment.

The start control of the defrosting operation is performed based on the continuous operation time signal of the compressor by the compressor continuous operation time integrating means (21) and the heat source side heat exchanger temperature signal detected by the pipe temperature detector (20). The defrosting operation start determining means (23) determines the start of the defrosting operation from the continuous time signal of the operation at a predetermined temperature or less by the continuous low temperature time integrating means (22), and the control means (26) controls the four-way switching valve (2). ), A first flow control device (9), a second flow control device (13), a fourth flow control device (17), and a first opening / closing valve (8a) of a first branch portion, This is realized by determining and controlling the opening or opening / closing of the two-way on-off valve (8b).

The defrosting operation end control includes a defrosting operation start determining means (23)
It is determined that the defrosting operation is started, and after the defrosting operation is started, the defrosting operation time signal integrated by the defrosting operation time integration means (24) and the heat source side heat exchange detected by the pipe temperature detector (21). The end of the defrosting operation is determined by the defrosting operation end determining means (25) based on the signal of the unit temperature, and the four-way switching valve (2), the first flow control device (9), and the Flow control device (13), fourth flow control device (17), first opening / closing valve (8a), second opening / closing valve (8b) of the first branch portion
It is realized by determining and controlling the opening degree or opening / closing of.

FIG. 7 is a flowchart of the control during the defrosting operation of the embodiment.

In steps (27) and (28), the continuous compressor operation time and the continuous pipe temperature low temperature period are determined, and if both are equal to or longer than a predetermined time, the defrosting operation control in step (29) and subsequent steps is started. In step (29), the four-way switching valve (2)
Is switched so that the heat exchanger on the heat source unit side is a condenser.
In step (29), the first flow control device (9) is fully closed. In step (31), the second flow control device (1
3) is fully opened. In step (41), the fourth flow control device (17) is fully opened. In step (42), the first
The first opening / closing valve (8a) and the second opening / closing valve (8a)
b) is closed.

After the defrosting operation is started, the defrosting operation time and the pipe temperature are determined in steps (43) and (44). If the defrosting operation time has continued for a predetermined time or longer, or the pipe temperature has exceeded the predetermined temperature. When it becomes, the control enters the defrosting operation end control of step (36) and subsequent steps. In step (36), the four-way switching valve (2) is returned to the state before the defrosting operation. In step (37), the first flow control device (9) is returned to the state before the defrosting operation. In step (38), the second flow control device (13) is returned to the state before the defrosting operation. In step (39), the fourth flow control device (17) is returned to the state before the defrosting operation. In the step (45), the on-off valve (8a) of the first port of the first branch portion,
The second opening / closing valve (8b) is returned to the state before the defrosting operation.

〔The invention's effect〕

As described above, the air conditioner of the present invention includes a compressor, a four-way switching valve, a heat source device side heat exchanger, an accumulator,
And a plurality of indoor units including an indoor heat exchanger, a first flow control device, and the like.
And a first branch in which one of the indoor heat exchangers of the plurality of indoor units is switchably connected to the first connection pipe or the second connection pipe. And the other of the indoor-side heat exchangers of the plurality of indoor units are connected to the second connection pipe via the first flow control device, and to the second connection pipe via the second flow control device. The connected second branch is connected via the second flow control device, and the second branch and the first connection pipe are connected via a fourth flow control device. And, a repeater incorporating the first branch, the second flow controller, the fourth flow controller and the second branch is disposed between the heat source unit and the plurality of indoor units. The first connection pipe is configured to have a larger diameter than the second connection pipe while being interposed, and the first and second connection pipes of the heat source device are configured to have a larger diameter. The switching valve is provided between the second connection pipe, the low pressure the first connection pipe, in which the switchable second connecting pipe to the high pressure.

When defrosting, the four-way switching valve is switched, the first branch is closed, the first flow control device is closed, and the second and fourth flow control devices are opened. Accordingly, the defrosting operation can be performed without a feeling of cool air in the room due to a decrease in the evaporation temperature of the indoor unit and freezing of the indoor unit.

In addition, since the first connection pipe on the indoor unit side is not cooled by the refrigerant, the heating operation starts quickly after returning from the defrosting operation.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram mainly showing a refrigerant of an air conditioner of one embodiment of the present invention. FIGS. 2, 3, and 4 show operating states during the cooling / heating operation in the embodiment of FIG. 1. FIG. 2 is an operating state diagram of only cooling or heating, and FIG. And FIG. 4 is a diagram showing an operation of simultaneous cooling and heating operation. FIG. 3 shows a heating main body (when the heating operation capacity is larger than the cooling operation capacity), and FIG. 4 shows a cooling main body (the cooling operation capacity is larger than the heating operation capacity). FIG. 6 is a driving operation state diagram showing a case where the distance is large. FIG. 5 is an operation state diagram at the time of the defrosting operation in the embodiment of FIG. Further, FIG.
Configuration diagram of the control for the defrosting operation in one embodiment of FIG.
FIG. 7 is a control flowchart. In the figure, (A) is a heat source device, (B), (C), (D)
Is an indoor unit having the same configuration, (E) is a repeater,
(1) is a compressor, (2) is a four-way switching valve, (3) is a heat source side heat exchanger, (4) is an accumulator, (5) is an indoor side heat exchanger, and (6) is a first connection. Plumbing, (6b), (6c),
(6d) is the second connection pipe on the indoor unit side, (7b), (7c),
(7d) is the second connection pipe on the indoor unit side, (8) is the switching valve section of the first branch, (8a) is the opening / closing valve of the first port, (8b)
Is the second opening / closing valve, (9) is the first flow control device, (1)
0) is a first branch, (11) is a second branch, (12) is a gas-liquid separator, (13) is a second flow controller, (14) is a bypass pipe, and (15) is a bypass pipe. Third flow control device, (16
(a), (16b), (16c), (16d) are the second and third heat exchange units, (19) is the first heat exchange unit, (17) is the fourth flow control device, (32) Is a third check valve, (33) is a fourth check valve, (34) is a fifth check valve, (35) is a sixth check valve,
(40) is a heat source device side switching valve. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

(57) [Claims] 1. A single heat source unit comprising a compressor, a four-way switching valve, a heat source side heat exchanger, etc., and a plurality of indoor units comprising an indoor side heat exchanger, a first flow control device, etc. First and second connection pipes for connecting a steam heat source unit and a plurality of indoor units, and one of the indoor heat exchangers of the plurality of indoor units to the first connection pipe or the second connection pipe. A first branch portion switchably connected to a connection pipe and the other of the indoor side heat exchangers of the plurality of indoor units connected via the first flow control device; A second branch connected to the first connection pipe via a fourth flow control apparatus, and a second branch portion connected to the second connection pipe via a flow control apparatus.
A cooling / heating device provided on the heat source side of the first and second connection pipes, and provided with a switching valve for switching and connecting to the heat source device so that the first connection pipe has a low pressure and the second connection pipe has a high pressure. In the air conditioner capable of operating simultaneously, the four-way switching valve is switched at the time of defrosting, the first branch portion and the first flow control device are closed, and the second and fourth flow control devices are closed.
An air conditioner characterized by opening a flow control device. 2. The air conditioner according to claim 1, wherein the first connection pipe has a larger diameter than the second connection pipe.