JPH08334272A - Air conditioner - Google Patents

Abstract

(57) [Abstract] [Purpose] In an air conditioner that uses a flammable refrigerant, when the refrigerant of the indoor heat exchanger is collected outside the room when the heating operation is stopped, the time required for the stop operation is reduced. , It is possible to solve various problems caused by switching to the cooling mode. [Structure] One end is a four-way switching valve (5) and a first solenoid valve (1
1) is connected to the gas side pipe (6) via the third solenoid valve (13), while the other end is connected to the liquid side pipe (6) between the second solenoid valve (12) and the pressure reducing valve (3). 4) Solenoid valve (14)
The bypass pipe (1) is connected to the bypass pipe (10) and is arranged in the outdoor unit (B).
It is possible to store a cooler (15) for cooling and liquefying a high-pressure gas refrigerant introduced through the third solenoid valve (13) in (0) and a high-pressure liquid refrigerant liquefied and cooled by the cooler (15). An automatic receiver (16) is provided, and the first on-off valve (11) is closed when the heating operation is stopped, while the third on-off valve (1) is closed.
The controller (40) controls to open 3).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for switching between heating operation and cooling operation, and more particularly to improvement of a pump down system when heating operation is stopped.

[0002]

2. Description of the Related Art Generally, in a conventional air conditioner, as shown in FIG.
As shown in FIG. 4, the compressor a, the indoor heat exchanger b, the pressure reducer c, the outdoor heat exchanger d, and the four-way switching valve e are provided with a refrigerant circuit connected by a pipe f, and the four-way switching valve is provided. The heating mode and the cooling mode can be switched by switching e. That is, in the heating mode, the discharge side pipe f of the compressor a is connected to the indoor heat exchanger b, and the suction side pipe f is connected to the outdoor heat exchanger d, as shown by the solid line in the figure. As a result, the refrigerant discharged from the compressor a circulates in the refrigerant circuit in the order of the indoor heat exchanger b, the pressure reducer c, and the outdoor heat exchanger d,
In the indoor heat exchanger b, the room can be heated by heat dissipation when the high-pressure gas refrigerant is condensed and liquefied. On the other hand, in the cooling mode, the discharge side is connected to the outdoor heat exchanger d and the suction side is connected to the indoor heat exchanger b, as shown by the broken line in the figure. As a result, the refrigerant discharged from the compressor a circulates in the order of the outdoor heat exchanger d, the pressure reducer c, and the indoor heat exchanger b, and the low-pressure liquid refrigerant evaporates in the indoor heat exchanger b. The interior of the room can be cooled by the heat absorption during the conversion.

By the way, in recent years, with respect to the refrigerant used in the above-mentioned air conditioner, from the viewpoint of protecting the ozone layer of the earth, use of a substitute of a chlorine-containing refrigerant has been promoted, and the alternative refrigerant does not contain chlorine. HFC-based refrigerants are considered to be the most promising, but in addition, propane and HFC-32
So-called flammable refrigerants are also listed as candidates. Then, in the air conditioner using the flammable refrigerant, the refrigerant of the indoor heat exchanger b is stopped when the operation is stopped so that the flammable refrigerant can be prevented from leaking into the room.
It has been proposed to collect them outside the room ("Barriers in the U.SAto Using Propane as a Ref
rigerant '' ASHRAE / NIST Refrigerants Conference-Aug
ust 1993, p.109-114).

Therefore, in the conventional air conditioner, in order to realize the above proposal, it is considered that the pump is down in the cooling mode. That is, while the compressor a is operating, the liquid side pipe f between the pressure reducer c and the indoor heat exchanger b is closed by the second closing valve g. Then, when the pressure sensor h detects that the pressure has dropped to about atmospheric pressure, the first closing valve i is closed to stop the operation of the compressor a. Thereby, the refrigerant of the indoor heat exchanger b can be collected in the outdoor heat exchanger d.

[0005]

However, in the conventional air conditioner described above, when the pump down is performed in the heating mode, the refrigerant in the outdoor heat exchanger d is heated in the indoor side, contrary to the case in the cooling mode. It will be gathered in the exchange b, which has the opposite result to the above proposal. Therefore, there is a constraint that the mode must be switched from heating to cooling when trying to stop the heating operation during the heating operation.

The operation required to stop the operation during heating will now be described in detail with reference to the time chart of FIG. 2 (b). First, the compressor a is temporarily stopped, and then the four-way switching valve e is used. To a cooling mode, and in that state, a predetermined time (for example, 3
Wait for (minutes) only. Next, the operation is performed for a predetermined time (for example, 20 minutes) in the cooling mode, it is confirmed that the steady state is reached, and the second electromagnetic valve g is closed. Then, the refrigerant in the indoor heat exchanger b flows in the order of the first electromagnetic valve i, the four-way switching valve e, the compressor a, and the four-way switching valve e and collects in the outdoor heat exchanger d. Then, when a predetermined time (for example, 3 minutes) elapses and the pressure sensor h detects that the pressure has decreased to about atmospheric pressure, the first electromagnetic valve i is closed and the compressor a is stopped.

In this way, the pump down is completed and the operation can be stopped. The following four problems are caused by these problems.

The time required for the heating stop operation becomes long (about 26 minutes in the above example).

During the switching to the operation in the cooling mode, the interior of the room is cooled even though it was being heated up to then, and the comfort is deteriorated.

It takes time to restart the heating operation during the heating stop operation. In other words, when the heating stop operation is stopped midway and the heating operation is restarted, the compressor a is temporarily stopped, the four-way switching valve e is switched to the heating mode, and the refrigerant is pressure-equalized in that state before the heating operation is started. You can enter the heating operation.

Since the start and stop of the device are repeated in a short time, a load is added to the compressor a, various devices, etc., and long-term reliability is easily deteriorated.

The present invention has been made in view of the above points, and its main purpose is to heat the refrigerant in the indoor heat exchanger to the outside by using a flammable refrigerant. It is possible to reduce the time required to stop the heating operation by allowing the pump to be down while the heating mode is stopped, and to temporarily switch to the cooling mode. It is to be able to eliminate various problems that occur.

[0013]

In order to achieve the above object, in the invention of claim 1, a bypass pipe bypassing the indoor heat exchanger is newly provided on the outside of the refrigerant circuit, and the bypass pipe stores By arranging the means, the refrigerant discharged from the compressor in the heating mode is introduced into the bypass pipe and stored in the storage means, so that the heating operation can be stopped without switching to the cooling mode.

Specifically, in the present invention, as shown in FIG. 1, a compression means (1), an indoor heat exchanger (2), a pressure reducing means (3), and an outdoor heat exchanger (4). ) And the switching means (5) are connected by a pipe (6).
In the heating operation, the gas refrigerant compressed by the compression means (1) is condensed and liquefied by the indoor heat exchanger (2) and then expanded by the decompression means (3) to expand the outdoor heat exchanger (4). ), The gas refrigerant compressed by the compression means (1) is condensed and liquefied by the outdoor heat exchanger (4) and then expanded by the decompression means (3) for indoor heat exchange during the cooling operation. It is premised on an air conditioner in which the flow of the refrigerant is switched by the switching means (5) so as to be vaporized and gasified in the device (2).

First, one end has the switching means (5).
And a liquid side pipe between the indoor heat exchanger (2) and the outdoor heat exchanger (4) while being connected to the gas side pipe (6) between the indoor heat exchanger (2) and the other end. A bypass pipe (10) connected to (6) and arranged on the outdoor side is provided.

Next, in the gas side pipe (6) between one end of the bypass pipe (10) and the indoor heat exchanger (2),
A first on-off valve (11) capable of opening and closing the gas side pipe (6)
The liquid side pipe (6) between the other end of the bypass pipe (10) and the outdoor heat exchanger (4).
A second opening / closing valve (12) capable of opening / closing, a third opening / closing valve (13) capable of opening / closing the bypass piping (10) at one end of the bypass piping (10), and a bypass piping (1
A fourth opening / closing valve (14) capable of opening and closing the bypass pipe (10) is arranged on the other end side of the (0).
At that time, during heating and cooling operations, the first and second on-off valves (11) and (12) are open, respectively, while the third and fourth on-off valves (13) and (14) are closed, respectively. Be present.

Further, in the bypass pipe (10) between the third on-off valve (13) and the fourth on-off valve (14), the third on-off valve (13) is passed through the bypass pipe (10). The cooling means (15) for cooling and liquefying the introduced refrigerant and the storage means (16) capable of storing the liquid refrigerant liquefied by the cooling means (15) are respectively provided.

When the heating operation is stopped, the first opening / closing valve (11) is closed while the third opening / closing valve (1) is closed.
3) so that the first and third on-off valves (11), (1)
A control means (40) for controlling 3) is provided.

In the invention of claim 2, based on the same premise as that of the invention of claim 1, as shown in FIG. 3, first, one end is a liquid between the indoor heat exchanger (2) and the pressure reducing means (3). A first bypass pipe (19) which is connected to the gas pipe (6) between the outdoor heat exchanger (4) and the switching means (5) while being connected to the gas pipe (6) While one end is connected to the gas side pipe (6) between the switching means (5) and the indoor heat exchanger (2), the other end is connected to one end of the first bypass pipe (19) and the pressure reducing means (3). ) And a second bypass pipe (20) connected to the liquid side pipe (6).

Next, in the gas side pipe (6) between one end of the second bypass pipe (20) and the indoor heat exchanger (2), the gas side pipe (6) can be opened and closed. 1 open / close valve (2
1) and the liquid side pipe (6) between one end of the first bypass pipe (19) and the other end of the second bypass pipe (20), the liquid side pipe (6) can be opened and closed. 2 open / close valve (22)
And a third opening / closing valve (23) capable of opening and closing the bypass pipe (20) on one end side of the second bypass pipe (20).
And a fourth opening / closing valve (24) at one end of the first bypass pipe (19) capable of opening and closing the bypass pipe (19).
The gas side pipe (6) between the outdoor heat exchanger (4) and the other end of the first bypass pipe (19) has a fifth opening / closing valve capable of opening and closing the gas pipe (6). (25) on the other end side of the first bypass pipe (19).
A first refrigerant for allowing the refrigerant in the bypass pipe (19) to flow out to the gas side pipe (6), and for restricting the refrigerant in the gas side pipe (6) from flowing into the first bypass pipe (19).
The check valve (26) and the other end side of the second bypass pipe (20) allow the refrigerant in the second bypass pipe (20) to flow out to the liquid side pipe (6). A second check valve (27) for restricting the refrigerant in the liquid side pipe (6) from flowing into the second bypass pipe (20) is arranged. At that time, during the heating and cooling operations, the first opening / closing valve (21), the second opening / closing valve (22), and the fifth opening / closing valve (25) are open, while the third and fourth opening / closing valves (23). ) And (24) are closed.

Then, the first bypass pipe (19)
The first on-off valve (2) in the first bypass pipe (19).
4) A sub pressure reducing means (28) for expanding the liquid refrigerant introduced via 4) and a heating means (29) for heating and gasifying the liquid refrigerant expanded by the sub pressure reducing means (28) are respectively arranged. To do so. On the other hand, the second bypass pipe (20)
The second on-off valve (2) in the second bypass pipe (20).
A cooling means (30) for cooling and liquefying the gas refrigerant introduced via 3) is provided.

When the heating operation is stopped, the first on-off valve (21), the second on-off valve (22) and the fifth on-off valve (25) are closed, while the third on-off valve (2).
3) and the fourth opening / closing valve (24) are opened so that the refrigerant in the refrigerant circuit (7) is stored in the outdoor heat exchanger (4) in a liquid refrigerant state. Valve (21)
A control means (40) for controlling (25) to (25) is provided.

According to a third aspect of the invention, in the above-mentioned second aspect of the invention, the heat source of the heating means (29) is the compression means (1).
It is assumed that it is composed of the high temperature part.

According to the invention of claim 4, in the invention of claim 2, the cooling means (30) is an outdoor heat exchanger (4).
It shall be composed of a fan (not shown) owned by.

According to a fifth aspect of the present invention, in the above second aspect of the invention, the first and second bypass pipes (19), (2) are provided.
0) between the liquid refrigerant in the first bypass pipe (19) and the second
A gas-liquid heat exchanger (31) that exchanges heat with the gas refrigerant in the bypass pipe (20) is provided. The gas-liquid heat exchanger (31) constitutes a heating means (29) and a cooling means (30).

According to a sixth aspect of the present invention, in addition to the fifth aspect of the invention, the second bypass pipe (20) is provided with a cooling means (30) including a gas-liquid heat exchanger (31). It is assumed that an auxiliary cooling means (32) for cooling and liquefying the gas refrigerant in (20) is provided.

The invention of claim 7 is the same as claim 1 or 2 above.
In the invention, it is assumed that a flammable refrigerant is used as the refrigerant.

[0028]

With the above construction, in the invention of claim 1, when the heating operation is stopped, the first opening / closing valve (11) is closed by the control means (40) while the third opening / closing valve (13) is opened. . Then, the refrigerant flowing from the switching means (5) toward the first opening / closing valve (11) flows into the bypass pipe (10) via the third opening / closing valve (13),
It is cooled and liquefied by the cooling means (15) and stored in the storage means (16). As a result, the refrigerant in the indoor heat exchanger (2) is collected in the outdoor storage means (16).

Therefore, since the refrigerant in the indoor heat exchanger (2) can be collected outside the room by pumping down in the heating mode, heating operation is required as compared with the conventional case where the cooling mode must be switched. There is no problem caused by switching to the cooling mode, for example, the time required to stop is reduced accordingly.

Further, the gas refrigerant in the bypass pipe (10) is condensed and liquefied into a liquid refrigerant, and the storage means (1
Since it is stored in 6), the space efficiency in storing the refrigerant is higher than that in the case where it is stored in the state of the gas refrigerant, and the outdoor equipment is increased in size due to the installation of the storage means (16). Can be suppressed.

According to the second aspect of the invention, when the heating operation is stopped, the control means (40) causes the fourth opening / closing valve (24) of the first bypass pipe (19) and the third opening / closing of the second bypass pipe (20). While the valves (23) are both open,
The first on-off valve (21), the second on-off valve (22) and the fifth on-off valve (25) are all closed. Then, the refrigerant flowing from the indoor heat exchanger (3) toward the second opening / closing valve (22) flows into the first bypass pipe (19) via the fourth opening / closing valve (24), Switching from the first check valve (26) after bypassing the decompression means (3) and the outdoor heat exchanger (4), expanded by the auxiliary decompression means (28) and heated and gasified by the heating means (29). It is guided to the means (5) and sucked into the compression means (1) in the state of the gas refrigerant. After that, the refrigerant discharged from the compression means (1) is the third on-off valve (23).
Through the second bypass pipe (20), bypassing the indoor heat exchanger (2) and liquefied by the cooling means (30), and then decompressed from the second check valve (27). (3)
And is collected in the outdoor heat exchanger (4) in the state of liquid refrigerant.

Therefore, as in the case of the first aspect of the present invention, the refrigerant in the indoor heat exchanger (2) can be collected outside by pumping down in the heating mode.

At this time, since the refrigerant can be collected in the outdoor heat exchanger (4), the outdoor equipment is different from the case of the invention of claim 1 in which a storage means needs to be newly provided. Is kept compact as a whole.

Further, during the operation other than the pump down in the heating mode, that is, the first and second bypass pipes (1
When 9) and (20) are not used, the refrigerant in the pipe (6) flows out into the first and second bypass pipes (19) and (20) from the other end side. It is regulated by stop valves (26) and (27). That is, in comparison with the case where the opening / closing valve is used to open / close the other end of each bypass pipe (19), (20), the first and second check valves (26), (27) have Therefore, the opening / closing operation is unnecessary, and therefore, the necessary valve operation amount that accompanies the provision of the first and second bypass pipes (19) and (20) can be reduced.

The high-pressure liquid refrigerant introduced into the first bypass pipe (19) is expanded by the auxiliary depressurizing means (28) into a low-pressure liquid refrigerant, and then heated by the heating means (29). After being turned into a low-pressure gas refrigerant, it flows out into the pipe (6) and is sucked into the compression means (1) via the switching means (5). Therefore, the pressure reducing means (3) and the outdoor heat exchanger (4) are provided in the first bypass pipe (19).
Liquid backing due to bypassing is avoided.

In the invention of claim 3, the heating means (2
9) receives heat from the high temperature part of the compression means (1), and the heat heats and gasifies the liquid refrigerant in the first bypass pipe (19). This eliminates the need for a dedicated heat source for the heating means (29).

In the fourth aspect of the invention, the gas refrigerant introduced into the second bypass pipe (20) is liquefied by the operation of the fan of the outdoor heat exchanger (4). As a result, when the refrigerant in the second bypass pipe (20) is cooled and liquefied, a dedicated cooling means is not required.

In the invention of claim 5, the liquid refrigerant in the first bypass pipe (19) and the gas refrigerant in the second bypass pipe (20) exchange heat with each other in the gas-liquid heat exchanger (31). In this way, the liquid refrigerant is heated and gasified, while the gas refrigerant is cooled and liquefied. Therefore, neither dedicated heating means nor cooling means is required.

In the sixth aspect of the invention, the gas refrigerant in the second bypass pipe (20) is liquefied by the gas-liquid heat exchanger (31) and the auxiliary cooling means (32). As a result, the cooling and liquefaction of the gas refrigerant in the second bypass pipe (20), which tends to be insufficient only with the liquid refrigerant in the first bypass pipe (19), is sufficiently performed.

According to the invention of claim 7, the combustible refrigerant in the indoor heat exchanger (2) is exposed to the outside (the storage means (16) or the outside heat exchanger (4)) by the pump down in the heating mode. ). Therefore, when the operation of the air conditioner is stopped, the flammable refrigerant is prevented from leaking from the indoor heat exchanger (2) into the room.

[0041]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 schematically shows the overall configuration of an air conditioner according to a first embodiment of the present invention, in which a combustible refrigerant such as propane or HFC-32 is used. There is.

The air conditioner includes a compressor (1) as a compression means, an indoor heat exchanger (2), a pressure reducing valve (3) as a pressure reducing means, and an outdoor heat exchanger (4). A refrigerant circuit (7) in which a four-way switching valve (5) as a switching means is connected by a pipe (6). The four-way switching valve (5) is switched to the heating mode shown by the solid line in the figure during the heating operation and to the cooling mode shown by the broken line in the figure during the cooling operation. That is, during the heating operation, the gas refrigerant compressed by the compressor (1) is condensed and liquefied by the indoor heat exchanger (2) and then expanded by the pressure reducing valve (3) and then expanded by the outdoor heat exchanger (4). Evaporate and gasify. On the other hand, during cooling operation, the compressor (1)
The gas refrigerant compressed in (1) is condensed and liquefied in the outdoor heat exchanger (4), then expanded by the pressure reducing valve (3), and evaporated and gasified in the indoor heat exchanger (2).

The indoor heat exchanger (2) is an indoor unit (A), while the compressor (1), pressure reducing valve (3), outdoor heat exchanger (4) and four-way switching valve (5). Are arranged indoors and outdoors as an outdoor unit (B). The indoor / outdoor units (A) and (B) include a gas side pipe (6) between the four-way switching valve (5) and the indoor heat exchanger (2), an indoor heat exchanger (2), and a decompressor. The liquid side pipe (6) between the valves (3) is connected to each other in a refrigerant circuit manner. Further, the gas side pipe (6) has a first solenoid valve (11) as a first opening / closing valve capable of opening and closing the pipe (6), and the liquid side pipe (6) has the pipe (6). A second solenoid valve (12) as a second opening / closing valve capable of opening and closing is provided. The first and second solenoid valves (11) and (12) are both open during heating and cooling operations.

The gas side pipe (6) between the four-way switching valve (5) and the indoor heat exchanger (2) has a first pressure sensor (41) for detecting the refrigerant pressure in the pipe (6). However, the liquid side pipe (6) between the indoor heat exchanger (2) and the pressure reducing valve (3) is provided with a second pressure sensor (42) for detecting the refrigerant pressure in the pipe (6). Has been done. The first pressure sensor (41) is used when pumping down in the cooling mode, and the second pressure sensor (42) is used when pumping down in the heating mode. Further, the suction side pipe (6) of the compressor (1) is provided with an accumulator (35) for separating the liquid refrigerant from the refrigerant sucked into the compressor (1).

The first and second pressure sensors (41),
The detection signal of (42) is input to the controller (40) as a control means. On the other hand, the controller (40) controls the operation of each device such as the compressor (1), the pressure reducing valve (3) and the four-way switching valve (5) according to various detection signals based on an instruction from the operator. It is done like this.

As a feature of the present invention, first, one end is connected to the gas side pipe (6) between the four-way switching valve (5) and the indoor heat exchanger (2), while the other end is connected to the above. A bypass pipe (10) connected to the liquid side pipe (6) between the second electromagnetic valve (12) and the pressure reducing valve (3) is arranged in the outdoor unit (B).

At one end of the bypass pipe (10),
A third solenoid valve (13) serving as a third opening / closing valve capable of opening / closing the bypass pipe (10) and a fourth solenoid valve serving as a fourth opening / closing valve capable of opening / closing the bypass pipe (10) on the other end side. Electromagnetic valves (14) are provided respectively. The third and fourth solenoid valves (13), (14) are closed during heating and cooling operations, respectively.

Further, in the bypass pipe (10) between the third solenoid valve (13) and the fourth solenoid valve (14), the third solenoid valve (13) is passed through the bypass pipe (10). A cooler (15) as a cooling means for cooling and liquefying the introduced refrigerant, and a receiver (16) as a storage means capable of storing the liquid refrigerant cooled and liquefied by the cooler (15).
And are respectively provided.

When the heating operation is stopped, the controller (40) closes the first electromagnetic valve (11) while opening the third electromagnetic valve (13).
And, the third solenoid valves (11) and (13) are controlled.

Next, the operation of the air conditioner when the operation is stopped in the heating mode will be described.

During the heating operation, the high-pressure gas refrigerant discharged from the compressor (1) is supplied to the four-way switching valve (5) and the first
It is sent to the indoor heat exchanger (2) via the electromagnetic valve (11), and when it is condensed and liquefied into a high-pressure liquid refrigerant, it radiates heat to heat the room. After that, the high-pressure liquid refrigerant reaches the pressure reducing valve (3) via the second electromagnetic valve (12), and expands there to become a low-pressure liquid refrigerant, and the next outdoor heat exchanger (4).
At the same time, it absorbs heat from the outside to be vaporized and becomes a low-pressure gas refrigerant, which is sucked into the compressor (1) via the four-way switching valve (5).

When the heating operation is stopped, the third solenoid valve (13) is operated while continuing the operation of the compressor (1) without operating the four-way switching valve (5) (in the heating mode). ) Is opened and the first solenoid valve (11) is closed. At this time, the fourth solenoid valve (14) is closed. Then, the refrigerant flowing from the four-way switching valve (5) toward the first solenoid valve (11) flows into the bypass pipe (10) via the third solenoid valve (13) and the cooler ( After being liquefied by cooling in (15), the receiver (1
It will be stored in 6). Then, when the detection value of the second pressure sensor (42) indicates the atmospheric pressure, the operation of the compressor (1) is stopped. This terminates the heating stop operation. That is, as shown in FIG. 2A, the time required to stop the heating operation is only the time required to pump down in the heating mode.

Therefore, according to this embodiment, the refrigerant in the indoor heat exchanger (2) can be collected in the receiver (16) on the outdoor side by pumping down in the heating mode, and thus the cooling mode. It is possible to reduce the time required to stop the heating operation by that amount compared to the conventional case where it is necessary to switch to, due to switching to the cooling mode described in the section of the problem to be solved by the invention. Various problems that occur can be solved.

When the pump is down, the high-pressure gas refrigerant introduced into the bypass pipe (10) is cooled and liquefied by the cooler (15), so that the high-pressure liquid refrigerant is supplied to the receiver (16). Can be stored. Therefore, as compared with the case where the refrigerant is stored in the state of high-pressure gas refrigerant, the space efficiency when storing the refrigerant can be increased, and the increase in size of the outdoor unit (B) accompanying the installation of the receiver (16) can be suppressed. You can

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
Shows schematically the overall configuration of the air conditioner according to
The same parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As a feature of the present invention, first, one end has a liquid side pipe (6) between the indoor heat exchanger (2) and the pressure reducing valve (3).
And a first bypass pipe (19) having the other end connected to the gas side pipe (6) between the outdoor heat exchanger (4) and the four-way switching valve (5), and one end being four-way. Gas side piping (6) between the switching valve (5) and the indoor heat exchanger (2)
The liquid side pipe (6) between the pressure reducing valve (3) and one end of the first bypass pipe (19) while the other end is connected to
And a second bypass pipe (20) connected to the indoor unit (B).

The gas side pipe (6) between one end of the second bypass pipe (20) and the indoor heat exchanger (2) serves as a first opening / closing valve capable of opening and closing the pipe (6). The first solenoid valve (21) also has a liquid side pipe (6) between one end of the first bypass pipe (19) and the other end of the second bypass pipe (20).
Has a second solenoid valve (22) as a second opening / closing valve capable of opening / closing the pipe (6), and the bypass pipe (20) can be opened and closed at one end of the second bypass pipe (20). Na third
A third solenoid valve (23) as an on-off valve is provided, and the bypass pipe (19) is provided at one end of the first bypass pipe (19).
Solenoid valve (24) as a fourth on-off valve capable of opening and closing
However, the gas side pipe (6) between the outdoor heat exchanger (4) and the other end of the first bypass pipe (19) is provided with a fifth opening / closing valve capable of opening and closing the pipe (6). 5th solenoid valve (2
5) are arranged respectively. At that time, during the heating and cooling operations, the first solenoid valve (21), the second solenoid valve (22) and the fifth solenoid valve (25) are open, respectively, while the third and fourth solenoid valves (23). ) And (24) are closed.

Furthermore, at the other end of the first bypass pipe (19), the refrigerant in the bypass pipe (19) is allowed to flow out to the gas side pipe (6), while the gas side pipe (6) is allowed. ), A first check valve (26) for restricting the refrigerant from flowing into the first bypass pipe (19), and the other end of the second bypass pipe (20) with the bypass pipe (20).
While allowing the refrigerant inside to flow out to the liquid side pipe (6),
The refrigerant in the liquid side pipe (6) is the first bypass pipe (19).
A second check valve (27) for restricting the inflow to the respective valves is provided.

Then, the first bypass pipe (19)
In the first bypass pipe (19).
4) a sub pressure reducing valve (28) as a sub pressure reducing means for expanding the liquid refrigerant introduced via the sub pressure reducing valve (28)
And a heater (29) as a heating means for heating and gasifying the liquid refrigerant expanded by. here,
The heat source of the heater (29) is composed of the high temperature part of the compressor (1). On the other hand, the second bypass pipe (20) has a third opening / closing valve (2) inside the second bypass pipe (20).
A cooler (30) is provided as a cooling means for cooling and liquefying the high-pressure gas refrigerant introduced via 3).
Here, the cooler (30) is composed of a fan (not shown) included in the outdoor heat exchanger (4).

When the heating operation is stopped, the controller (40) closes the first opening / closing valve (21), the second opening / closing valve (22) and the fifth opening / closing valve (25) while the third opening The on-off valve (23) and the fourth on-off valve (24) are opened so that the refrigerant in the refrigerant circuit (7) is stored in the outdoor heat exchanger (4) in a liquid refrigerant state. The five on-off valves (21) to (25) are controlled.

Next, a procedure for stopping the operation of the above air conditioner when the operation is performed in the heating mode will be described.

When the heating operation is stopped, the operation of the compressor (1) is continued without operating the four-way switching valve (5) (in the heating mode), and the third and fourth solenoid valves ( 23) and (24) are both opened, and the first solenoid valve (2
1), the second solenoid valve (22) and the fifth solenoid valve (25) are both closed. Then, the refrigerant flowing from the indoor heat exchanger (2) toward the second electromagnetic valve (22) flows into the first bypass pipe (19) via the fourth electromagnetic valve (24), It bypasses the pressure reducing valve (3) and the outdoor heat exchanger (4), is guided to the four-way switching valve (5), and is sucked into the compressor (1). After that, the refrigerant discharged from the compressor (1) is
It flows into the second bypass pipe (20) through the fourth electromagnetic valve (24), bypasses the indoor heat exchanger (2) and is guided to the pressure reducing valve (3), and the outdoor heat exchanger. Collected in (4). At this time, if the pressure reducing valve (3) is fully opened, high-pressure liquid refrigerant is stored in the outdoor heat exchanger (4).

Therefore, according to this embodiment, the refrigerant in the indoor heat exchanger (2) can be collected outside by performing pump down in the heating mode. The same effect as can be obtained.

Further, the refrigerant is transferred to the outdoor heat exchanger (4).
Therefore, the outdoor unit (B) can be made compact as compared with the case of the above-described first embodiment in which a receiver needs to be newly provided.

The high-pressure liquid refrigerant introduced into the first bypass pipe (19) is expanded by the auxiliary pressure reducing valve (28) into a low-pressure liquid refrigerant, and then heated and gasified by the heater (29). Since the low-pressure gas refrigerant can be made to flow out to the pipe (6) and sucked into the compressor (1) via the four-way switching valve (5), the first bypass pipe (1
It is possible to avoid liquid backing caused by bypassing the pressure reducing valve (3) and the outdoor heat exchanger (4) in 9). At that time, since the heater (29) is configured to heat and gasify the liquid refrigerant by the heat from the high temperature part of the compressor (1), a dedicated heat source for the heater (29) may be unnecessary. it can.

On the other hand, the high-pressure gas refrigerant introduced into the second bypass pipe (20) is cooled and liquefied by the cooler (30) and in the state of high-pressure liquid refrigerant, the outdoor heat exchanger (4).
Since it is stored in, it is possible to store efficiently in space. At that time, the cooler (3
Since 0) is configured by the fan of the outdoor heat exchanger (4), it is possible to eliminate the need for a dedicated cooling means for cooling and liquefying the refrigerant in the second bypass pipe (20). it can.

Further, when the first and second bypass pipes (19) and (20) are not used, the pipe (6)
The refrigerant in the first and second bypass pipes (19), (2
Since it is possible to regulate the outflow from the other end side into the inside 0) without opening and closing the valve, such opening and closing operation of the opening and closing valve is unnecessary, and therefore, the first and second bypass pipes ( It is possible to reduce the required valve operation amount that occurs accompanying the provision of 19) and (20).

In the second embodiment, the pressure reducing valve (3) is fully opened to store the high pressure liquid refrigerant in the outdoor heat exchanger (4), but the pressure reducing means is a capillary. In order to be able to store high pressure liquid refrigerant,
A bypass circuit may be provided to connect the inlet side and the outlet side of the capillary to each other.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention.
1 schematically shows the overall configuration of the air conditioner according to the present invention.
The same parts as those in the second embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As a feature of the present invention, the liquid refrigerant in the first bypass pipe (19) and the gas refrigerant in the second bypass pipe (20) are provided between the first and second bypass pipes (19) and (20). A gas-liquid heat exchanger (31) for exchanging heat between the two is interposed, and heating means (29) and cooling means (30) are provided.
Is composed of the gas-liquid heat exchanger (31).

In the second bypass pipe (20), in addition to the cooling means composed of the gas-liquid heat exchanger (31), auxiliary cooling means for cooling and liquefying the gas refrigerant in the second bypass pipe (20). An auxiliary cooler (32) is provided.

Therefore, according to this embodiment as well, it is possible to obtain substantially the same effect as in the case of the above-mentioned second embodiment, and at that time, the second refrigerant which is not sufficient only by the liquid refrigerant in the first bypass pipe (19). The gas refrigerant in the bypass pipe (20) can be sufficiently liquefied for cooling by using the auxiliary cooler (32) together.

[0073]

As described above, according to the invention of claim 1, the refrigerant circuit in which the compression means, the indoor heat exchanger, the pressure reducing means, the outdoor heat exchanger and the switching means are sequentially connected by piping. In the air conditioner, wherein the heating mode and the cooling mode are switched by the switching operation of the switching means, the refrigerant flowing from the switching means toward the indoor heat exchanger during the heating operation is arranged outside the room. It is introduced into the bypass pipe, and is cooled and liquefied by the cooling means so that it can be efficiently stored in the storage means in the state of liquid refrigerant, so the heating performed to collect the refrigerant of the indoor heat exchanger outside the room. Pump down at the time of operation stop can be performed in the heating mode, and the time required to stop the heating operation can be shortened by that much, and various other factors caused by switching to the cooling mode can be achieved. It is possible to eliminate the degree, it is possible to suppress the increase in size of the outdoor equipment associated with the installation of the reservoir means.

According to the second aspect of the present invention, there is provided a refrigerant circuit in which the compression means, the indoor heat exchanger, the pressure reducing means, the outdoor heat exchanger and the switching means are sequentially connected by piping, and the switching means is switched. In the air conditioner configured to switch between the heating mode and the cooling mode by the operation, the refrigerant flowing out from the indoor heat exchanger toward the pressure reducing means during the heating operation is first
Introduced into the bypass pipe, expanded by the auxiliary decompression means while bypassing the decompression means and the outdoor heat exchanger and heated and gasified by the heating means, and then led to the switching means to avoid liquid back, while the switching means The refrigerant flowing from the indoor heat exchanger to the indoor heat exchanger is introduced into the second bypass pipe, and is liquefied by the cooling means while bypassing the indoor heat exchanger and then guided to the decompression means to heat the outdoor heat in the liquid refrigerant state. Since the heat can be stored in the exchanger, the pump down when the heating operation is stopped for collecting the refrigerant in the indoor heat exchanger to the outside can be performed in the heating mode. Therefore, the invention according to claim 1 can be achieved. Not only can the same effect be exhibited, but since the refrigerant can be collected in the outdoor heat exchanger, the outdoor equipment is provided as a whole more compactly than the case of the invention of claim 1 in which a storage means is newly provided. It can be suppressed to.

Further, the first and second check valves are respectively arranged on the other end sides of the first and second bypass pipes, and the refrigerant in the pipes is used when the first and second bypass pipes are not used. Since it is possible to regulate the outflow to the other ends of the first and second bypass pipes without providing an on-off valve, a necessary valve operation that occurs accompanying the provision of the first and second bypass pipes. The amount can be kept small.

According to the invention of claim 3, since the heat source of the heating means is constituted by the high temperature part of the compression means, the heat source dedicated to the heating means can be eliminated.

According to the fourth aspect of the present invention, the cooling means is constituted by the fan of the outdoor heat exchanger. Therefore, the dedicated cooling means for cooling and liquefying the refrigerant in the second bypass pipe is used. Can be eliminated.

According to the invention of claim 5, since the heating means and the cooling means are constituted by a gas-liquid heat exchanger interposed between the first and second bypass pipes, a dedicated heating means and Both cooling means can be dispensed with.

According to the sixth aspect of the invention, in addition to the cooling means composed of the gas-liquid heat exchanger, the auxiliary cooling means for cooling and liquefying the gas refrigerant in the second bypass piping is provided in the second bypass piping. As a result, the cooling and liquefaction of the gas refrigerant in the second bypass pipe, which is insufficient only by the liquid refrigerant in the first bypass pipe, can be sufficiently performed.

According to the seventh aspect of the invention, since the flammable refrigerant is used as the refrigerant, when the operation of the air conditioner is stopped, the flammable refrigerant is removed from the indoor heat exchanger. Leakage into the room can be prevented in advance.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a time chart showing the time required for the heating operation stop operation in comparison with the conventional case.

FIG. 3 is a view corresponding to FIG. 1, showing an air conditioner according to a second embodiment of the present invention.

FIG. 4 is a view corresponding to FIG. 1, showing an air conditioner according to a third embodiment of the present invention.

FIG. 5 is a view corresponding to FIG. 1 showing a conventional air conditioner.

[Explanation of symbols]

 (1) Compressor (compressing means) (2) Indoor heat exchanger (3) Pressure reducing valve (pressure reducing means) (4) Outdoor heat exchanger (5) Four-way switching valve (switching means) (6) Pipe (7) ) Refrigerant circuit (10) Bypass piping (11) First solenoid valve (first opening / closing valve) (12) Second solenoid valve (second opening / closing valve) (13) Third solenoid valve (third opening / closing valve) (14) Fourth solenoid valve (fourth opening / closing valve) (15) Cooler (cooling means) (16) Receiver (reserving means) (17) Controller (control means) (19) First bypass pipe (20) Second bypass pipe (21) ) 1st solenoid valve (1st opening / closing valve) (22) 2nd solenoid valve (2nd opening / closing valve) (23) 3rd solenoid valve (3rd opening / closing valve) (24) 4th solenoid valve (4th opening / closing valve) (25) Fifth solenoid valve (fifth opening / closing valve) (26) First check valve (27) Second check valve (28) Sub pressure reducing valve (Sub-decompression means) (29) Heater (heating means) (30) Cooler (cooling means) (31) Gas-liquid heat exchanger (32) Auxiliary cooler (auxiliary cooling means) (37) Controller (control means)

Claims (7)

[Claims] 1. A compression means (1), an indoor heat exchanger (2), a pressure reducing means (3), and an outdoor heat exchanger (4).
And a switching means (5) are connected by a pipe (6), and a refrigerant circuit (7) is provided. During heating operation, the gas refrigerant compressed by the compression means (1) is supplied to the indoor heat exchanger (2). After being condensed and liquefied by the system, it is expanded by the decompression means (3) and vaporized and gasified by the outdoor heat exchanger (4), while the gas refrigerant compressed by the compression means (1) during the cooling operation is the outdoor heat exchanger. After being condensed and liquefied in (4), it is expanded by the decompression means (3) to be indoor heat exchanger (2).
The above-mentioned switching means (5) so that they are vaporized by
In the air conditioner in which the flow of the refrigerant is switched by the one end, one end is connected to the gas side pipe (6) between the switching means (5) and the indoor heat exchanger (2), while the other end is connected. A bypass pipe (10) connected to the liquid side pipe (6) between the indoor heat exchanger (2) and the outdoor heat exchanger (4) and arranged on the outdoor side; and the bypass pipe (10). First on-off valve which is arranged in the gas side pipe (6) between one end of the chamber and the indoor side heat exchanger (2), which can open and close the gas side pipe (6) and is open during heating and cooling operations. (11) and the liquid side pipe (6) between the other end of the bypass pipe (10) and the outdoor heat exchanger (4), and the liquid side pipe (6) can be opened and closed. The second opening / closing valve (12) that is open during heating and cooling operations and the one end of the bypass pipe (10) A third opening / closing valve (13) which is installed and is capable of opening and closing the bypass pipe (10) and is closed during heating and cooling operations; and the bypass pipe (10) which is disposed on the other end side of the bypass pipe (10). A fourth opening / closing valve (14) that can open and close 10) and is closed during heating and cooling operations, and a bypass pipe (10) between the third opening / closing valve (13) and the fourth opening / closing valve (14). The bypass pipe (1
0) cooling means (15) for cooling and liquefying the refrigerant introduced through the third on-off valve (13), and storage means capable of storing the liquid refrigerant liquefied by the cooling means (15). (16), when the heating operation is stopped, the first on-off valve (11) is closed while the third on-off valve (13) is opened so that the first and third on-off valves (11), An air conditioner comprising: a control means (40) for controlling (13). 2. A compression means (1), an indoor heat exchanger (2), a pressure reducing means (3), and an outdoor heat exchanger (4).
And a switching means (5) are connected by a pipe (6), and a refrigerant circuit (7) is provided. During heating operation, the gas refrigerant compressed by the compression means (1) is supplied to the indoor heat exchanger (2). After being condensed and liquefied by the system, it is expanded by the decompression means (3) and vaporized and gasified by the outdoor heat exchanger (4), while the gas refrigerant compressed by the compression means (1) during the cooling operation is the outdoor heat exchanger. After being condensed and liquefied in (4), it is expanded by the decompression means (3) to be indoor heat exchanger (2).
The above-mentioned switching means (5) so that they are vaporized by
In the air conditioner in which the flow of the refrigerant is switched by, one end is connected to the liquid side pipe (6) between the indoor heat exchanger (2) and the pressure reducing means (3), while the other end is connected. A first bypass pipe (19) connected to a gas side pipe (6) between the outdoor heat exchanger (4) and the switching means (5), and one end of the switching means (5) and the indoor heat exchange. While being connected to the gas side pipe (6) between the vessel (2), the other end is connected to the liquid side pipe (6) between one end of the first bypass pipe (19) and the pressure reducing means (3). The second bypass pipe (20) thus formed, and the gas side pipe (6) between one end of the second bypass pipe (20) and the indoor heat exchanger (2). A first opening / closing valve (21) capable of opening and closing (6) and opened during heating and cooling operations; Disposed on the liquid side pipe (6) between one end of the gas pipe (19) and the other end of the second bypass pipe (20),
A second opening / closing valve (22) that can open and close the liquid side pipe (6) and is open during heating and cooling operations, and is arranged at one end side of the second bypass pipe (20), and the bypass pipe (20) is provided. ) Is openable and closable and is closed at the time of heating and cooling operation, and a third on-off valve (23) is provided at one end side of the first bypass pipe (19), and the bypass pipe (19) can be opened and closed. A fourth on-off valve (24) which is closed during heating and cooling operations, the outdoor heat exchanger (4) and the first bypass pipe (19).
A fifth opening / closing valve (25) which is disposed in the gas side pipe (6) between the other end of the gas pipe and the gas pipe (6) and can be opened and closed during heating and cooling operations; The refrigerant in the first bypass pipe (19) is disposed on the other end side of the pipe (19) and the refrigerant in the gas bypass pipe (6)
A first check valve (26) for restricting the refrigerant in the gas side pipe (6) from flowing into the first bypass pipe (19) while allowing the outflow to the second bypass pipe (20). ) Is arranged on the other end side of the second bypass pipe (20) to allow the refrigerant in the second bypass pipe (20) to flow out to the liquid side pipe (6), while the refrigerant in the liquid side pipe (6) passes through the second bypass pipe (6). Second for restricting the flow into the pipe (20)
The check valve (27) and the first bypass pipe (19) are arranged to expand the liquid refrigerant introduced into the first bypass pipe (19) via the fourth opening / closing valve (24). An auxiliary decompression means (28), a heating means (29) arranged in the first bypass pipe (19) for heating and gasifying the liquid refrigerant expanded by the auxiliary decompression means (28), and the second bypass pipe A cooling means (30) arranged in (20) for cooling and liquefying the gas refrigerant introduced into the second bypass pipe (20) through the third opening / closing valve (23), and the heating operation is stopped. Sometimes, the first opening / closing valve (21),
The second opening / closing valve (22) and the fifth opening / closing valve (25) are closed, respectively, while the third opening / closing valve (23) and the fourth opening / closing valve (24) are opened, so that the refrigerant in the refrigerant circuit (7) is liquefied. A control means (40) for controlling the first to fifth on-off valves (21) to (25) so that the refrigerant is stored in the outdoor heat exchanger (4) in the state of refrigerant. Air conditioner. 3. The air conditioner according to claim 2, wherein the heat source of the heating means (29) is constituted by the high temperature part of the compression means (1). 4. The air conditioner according to claim 2, wherein the cooling means (30) is constituted by a fan included in the outdoor heat exchanger (4). 5. The air conditioner according to claim 2, wherein the liquid refrigerant in the first bypass pipe (19) and the second bypass pipe (20) are provided between the first and second bypass pipes (19), (20). ), A gas-liquid heat exchanger (31) for exchanging heat with the gas refrigerant inside is provided, and the heating means (29) and the cooling means (30) are constituted by the gas-liquid heat exchanger (31). An air conditioner characterized by being. 6. The air conditioner according to claim 5, wherein the second bypass pipe (20) includes a cooling means (30) including a gas-liquid heat exchanger (31), and the second bypass pipe (20). Auxiliary cooling means (3) for cooling and liquefying the gas refrigerant inside
2) is provided, The air conditioner characterized by the above-mentioned. 7. The air conditioner according to claim 1, wherein a flammable refrigerant is used as the refrigerant.