ES2928874T3 - Air conditioner and indoor unit - Google Patents

Abstract

An air conditioning device (1) includes an outdoor unit (2), a refrigerant fluid communication pipe (5), a refrigerant gas communication pipe (6) and indoor units (3a-3d) arranged in a space for be conditioned. The indoor units (3a-3d) include indoor expansion valves (51a-51d) and communication side indoor refrigerant fluid pipes (72a-72d). The lining materials (11a-11d) are provided in the brazing sections (82a-82d) where the indoor expansion valves (51a-51b) and the supply side indoor fluid refrigerant pipes are brazed and connected. communication (72a-72d). (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Air conditioner and indoor unit

technical field

The present description refers to air conditioners and indoor units, and more particularly, it refers to an air conditioner configured in such a way that an outdoor unit and an indoor unit arranged in an air conditioning target space are connected. to each other through a refrigerant liquid connection pipe and a refrigerant gas connection pipe and to an indoor unit used for the air conditioner.

Background art

An existing air conditioner is configured in such a way that an outdoor unit and an indoor unit arranged in an air conditioning target space are connected to each other through a refrigerant liquid connection pipe and a gas connection pipe. refrigerant. An example of such an air conditioner, described in PTL 1 (International Publication No. 2015/029160), performs a two-phase refrigerant supply by decompressing a refrigerant to bring it into a gas-liquid two-phase state in an outdoor unit and then sending the refrigerant to an indoor unit through a refrigerant liquid connection pipe. The air conditioner supplying two-phase refrigerant can reduce the amount of refrigerant retained by the entire air conditioner in the amount that the refrigerant flowing through the refrigerant liquid connection pipe changes to the two-phase gas-gas state. liquid. Decreasing the amount of refrigerant can decrease the influence on the environment in case the refrigerant leaks out of the air conditioner. Other air conditioners are described in patent documents WO2016/208470A1, JP201201339A, JPH0252967A. Document WO2016/208470 is considered the closest prior art and shows units according to the preamble of claims 1 and 12.

Compendium of the invention

The object of the present invention is to provide an air conditioner and an indoor unit that improves on the above-mentioned prior art. This object is achieved by the air conditioner and the indoor unit according to the corresponding attached claims.

Although the amount of refrigerant held by the whole air conditioner can be decreased to a certain degree by two-phase refrigerant feeding, as described in PTL 1, the decrease in the amount of refrigerant is occasionally not enough for countermeasure to refrigerant leakage. . This is because, when the refrigerant leaks from the indoor unit, the concentration of the refrigerant increases in the target air conditioning space where the indoor unit involving leakage of the refrigerant is arranged, and the concentration may exceed its allowable value.

To address this, a stop valve can be added to both the liquid side and the gas side of the indoor unit to isolate the indoor unit involving refrigerant leakage and to reduce refrigerant leakage into the conditioning target space. of air.

Adding the stop valves to both the liquid side and the gas side of the indoor unit, however, increases the cost and further increases the size of the indoor unit if the stop valves on the liquid side and the gas side gas side are arranged in the indoor unit.

The challenges of the present description are, in an air conditioner configured so that an outdoor unit and an indoor unit arranged in an air conditioning target space are connected to each other through a refrigerant liquid connection pipe and a refrigerant gas connecting pipe, as well as an indoor unit used for the air conditioner, to minimize the increases in the cost and size of the indoor unit, and to enable the addition of a refrigerant shut-off function when a Refrigerant leak from indoor unit.

An air conditioner according to a first aspect is an air conditioner including an outdoor unit, a refrigerant liquid connection pipe and a refrigerant gas connection pipe, an indoor unit, a gas-side stop valve, refrigerant leak detecting means and a control unit. The indoor unit is connected to the outdoor unit through the refrigerant liquid connection pipe and the refrigerant gas connection pipe, is arranged in an air conditioning target space, and includes an indoor heat exchanger, a indoor expansion valve, an indoor refrigerant liquid pipe of the heat exchange side and an indoor refrigerant liquid pipe of the connection side. The indoor heat exchanger performs heat exchange between a refrigerant, which circulates between the indoor unit and the outdoor unit through the refrigerant liquid connection pipe and the refrigerant gas connection pipe, and an air, that is sent to the target air conditioning space. The internal expansion valve decompresses the refrigerant. The heat exchanger side indoor refrigerant liquid pipe connects a liquid side of the indoor heat exchanger to the indoor expansion valve. liquid pipeline connection side indoor refrigerant connects the indoor expansion valve to the refrigerant liquid connection pipe. The gas side stop valve is connected to the gas side of the indoor heat exchanger. The refrigerant leak detecting means detects leaks of the refrigerant. The refrigerant leak detecting means may be a refrigerant sensor that directly detects the refrigerant leak, or it may be one that estimates the presence or amount of leaked refrigerant based on the relationship between the temperature of the refrigerant in the heat exchanger of indoor and atmospheric temperature of the indoor heat exchanger. The indoor expansion valve is connected to the connection side indoor refrigerant liquid pipe by brazing. A brazing portion welds the indoor expansion valve and the indoor refrigerant liquid pipe of the connection side is provided with a coating material. The control unit causes the indoor expansion valve and the gas side stop valve to close in accordance with information from the refrigerant leak detecting means when there is a refrigerant leak.

To add the refrigerant stop function for the situation where the refrigerant leaks from the indoor unit, providing stop valves on both the liquid side and the gas side of the indoor unit may increase the cost and the size of the indoor unit. In order to minimize the increase in cost and size of the indoor unit, it is desirable to use the indoor expansion valve also as a stop valve on the liquid side for the situation that refrigerant leaks from the indoor unit. .

In the indoor unit arranged in the air conditioning objective space, however, the connection side indoor refrigerant liquid pipe connecting the indoor expansion valve to the refrigerant liquid connection pipe is connected to the valve internal expansion by brazing. The brazing portion brazing the indoor expansion valve and the indoor refrigerant liquid pipe of the connection side may corrode and refrigerant may leak from the corroded portion. When refrigerant leaks from the brazing portion that brazes the indoor expansion valve and the indoor refrigerant liquid pipe of the connection side, refrigerant is continuously supplied from the refrigerant liquid connection pipe to the brazing portion. strong, although the indoor expansion valve closes to function as a stop valve on the liquid side of the indoor unit. The refrigerant may continuously leak from the indoor unit to the target air conditioning space. Thus, it is difficult to use the indoor expansion valve also as stop valve on the liquid side of the indoor unit unless said refrigerant leakage from the brazing portion brazing the expansion valve is reduced. indoor and the indoor refrigerant liquid pipe of the connection side.

In this case, by providing the lining material on the brazing portion that welds the indoor expansion valve and the connection side indoor refrigerant liquid pipe as described above, the leakage of refrigerant from the expansion valve is reduced. brazing portion brazing the indoor expansion valve and the indoor refrigerant liquid pipe of the connection side, and the indoor expansion valve can also be used as a stop valve on the liquid side of the indoor unit . As long as the indoor expansion valve can also be used as a stop valve on the liquid side of the indoor unit, the increase in cost and size of the indoor unit can be suppressed by that amount.

Accordingly, the refrigerant shutdown function for the situation that refrigerant leaks from the indoor unit can be added while reducing the increase in cost and size of the indoor unit due to the provision of the valve. closure on the liquid side of the indoor unit as much as possible.

For the coating material, any material can be used as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be used. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be used.

An air conditioner according to a second aspect is the air conditioner according to the first aspect, wherein the connection side indoor refrigerant liquid pipe includes a first connection side indoor refrigerant liquid pipe connected to the check valve. expansion pipe, a second connection-side indoor refrigerant liquid pipe connected to the refrigerant connection pipe, and a filter which is connected between the first connection-side indoor refrigerant liquid pipe and the second expansion pipe. port side indoor refrigerant. The filter is connected to the first connection-side indoor refrigerant liquid pipe and the second connection-side indoor refrigerant liquid pipe by brazing. The brazing portions brazing the filter to the first connection-side indoor refrigerant liquid pipe and the second connection-side indoor refrigerant liquid pipe, each being provided with a coating material.

In the indoor unit arranged in the air conditioning objective space, a filter can be provided to reduce the ingress of foreign substances, etc., into the connection side indoor refrigerant liquid pipe and the indoor expansion valve . The filter is also connected to the connection side indoor refrigerant liquid pipe (the first connection side indoor refrigerant liquid pipe and the second connection side indoor refrigerant liquid pipe) by brazing. Due to this, the brazing portions which weld the filter with the first connection side indoor refrigerant liquid pipe and the second connection side indoor refrigerant liquid pipe may be corroded and the refrigerant may leak from corroded portions. This makes it difficult to use the indoor expansion valve also as a stop valve on the liquid side of the indoor unit, such as the brazing portion that welds the indoor expansion valve and the indoor refrigerant liquid pipe of the indoor unit. connection side (the first indoor refrigerant liquid pipe of the connection side).

In this case, by providing the coating materials on the brazing portions that weld the filter with the first connection-side indoor refrigerant liquid pipe and the second connection-side indoor refrigerant liquid pipe as described above, the leakage of refrigerant from the brazing portions brazing the filter with the first connection side indoor refrigerant liquid pipe and the second connection side indoor refrigerant liquid pipe, and the expansion valve is reduced The indoor unit can also be used as a stop valve on the liquid side of the indoor unit.

Even in the case that the filter is provided in the connection side indoor refrigerant liquid pipe, the refrigerant shutdown function for the situation that refrigerant leaks from the indoor unit can be added while reducing the increase in the cost and the size of the indoor unit due to the provision of the stop valve on the liquid side of the indoor unit as much as possible.

For the coating material, any material can be used as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be used. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be used.

An air conditioner according to a third aspect is the air conditioner according to the first or the second aspect, wherein the outdoor unit includes an outdoor heat exchanger and a liquid pressure adjusting expansion valve. When the refrigerant is sent from the outdoor heat exchanger to the indoor unit through the refrigerant liquid connection pipe, the control unit controls the liquid pressure adjusting expansion valve to decompress the refrigerant flowing into through the connecting pipe of refrigerant liquid to bring it into a gas-liquid two-phase state, and controls the indoor expansion valve to decompress the refrigerant decompressed by the liquid pressure adjustment expansion valve.

Since the outdoor unit includes the liquid pressure adjustment expansion valve described above, the two-phase refrigerant supply of decompressing the refrigerant to bring it to the two-phase gas-liquid state in the outdoor unit and then sending the refrigerant can be realized. to the indoor unit through the refrigerant liquid connection pipe. In this way, the amount of refrigerant retained by the whole air conditioner can be reduced by the amount that the refrigerant flowing through the refrigerant liquid connecting pipe changes to the gas-liquid two-phase state through the refrigerant supply. two-phase refrigerant. However, although the amount of refrigerant retained by the whole air conditioner can be reduced to a certain degree through the two-phase refrigerant supply, when the refrigerant leaks from the indoor unit, the refrigerant concentration increases in the target space of refrigerant. air conditioning where the indoor unit is arranged which involves leakage of the refrigerant, and the concentration may exceed its allowable value. In such a case, the two-phase refrigerant supply is occasionally not enough to counter refrigerant leakage.

In this case, by providing the lining material on the brazing portion that welds the indoor expansion valve and the connection side indoor refrigerant liquid pipe as described above, the leakage of refrigerant from the expansion valve is reduced. brazing portion brazing the indoor expansion valve and the indoor refrigerant liquid pipe of the connection side, and the indoor expansion valve can also be used as a stop valve on the liquid side of the indoor unit .

Therefore, even in the case that the two-phase refrigerant supply is not enough to counter refrigerant leakage, the refrigerant shutdown function for the situation where refrigerant leaks from the indoor unit can be added while reduces the increase in cost and size of the indoor unit due to the provision of the stop valve on the liquid side of the indoor unit as much as possible. The addition of the refrigerant shutdown function makes the countermeasure to refrigerant leakage sufficient.

An air conditioner according to a fourth aspect is the air conditioner according to any one of the first to third aspects, wherein the indoor unit includes a plurality of indoor units, and the gas side stop valve is provided for correspond to each of the indoor units.

In this case, the plurality of indoor units and the plurality of gas-side stop valves are provided as described above. Even with this configuration, the refrigerant shutdown function can be added for the situation where refrigerant leaks from the indoor units while reducing the increase in the cost and size of the indoor units due to the provision of stop valves on liquid sides of indoor units as much as possible.

An air conditioner according to a fifth aspect is the air conditioner according to the fourth aspect, in which the control unit makes only the indoor expansion valve and the gas side stop valve corresponding to the indoor unit in which the refrigerant leaks between the plurality of indoor units are closed in accordance with the information of the refrigerant leak detecting means when the refrigerant leaks. drain.

In this case, when the refrigerant leaks from the indoor unit, only the indoor unit in which the refrigerant leaks occurs can be isolated as described above.

Therefore, the indoor unit in which there is no refrigerant leakage can continue operation.

An air conditioner according to a sixth aspect is the air conditioner according to any one of the first to fifth aspects, wherein the refrigerant gas connection pipe is provided with an external stop valve unit including the stop valve of the gas side.

In this case, since the gas side stop valve is arranged outside the indoor unit, as described above, the increase in the size of the indoor unit can be suppressed.

An air conditioner according to a seventh aspect is the air conditioner according to the sixth aspect, in which the stop valve on the gas side is connected by brazing to an indoor side gas connecting pipe which is connected to a refrigerant gas connection pipe portion on an indoor unit side, and an outdoor side gas connection pipe which is connected to a refrigerant gas connection pipe portion on an indoor unit side. Exterior. A brazing portion that welds the stop valve on the gas side and the gas connection pipe on the outdoor side is also provided with a lining material.

In the external stop valve unit, the gas side stop valve is connected to the gas connection pipe connected to the refrigerant gas connection pipe (the indoor side gas connection pipe and the gas tube on the outside) by brazing. Due to this, the brazing portion brazing the gas side stop valve and the outdoor side gas connection pipe may corrode and refrigerant may leak from the corroded portion. On the contrary, when the outdoor stop valve unit is arranged in the air conditioning target space together with the indoor unit, if refrigerant leaks from the brazing portion brazing the gas side stop valve and the outdoor side gas connection pipe, refrigerant is continuously supplied from the refrigerant gas connection pipe to the welding portion, even though the gas side stop valve is closed, and the refrigerant can continuously leak from the welding portion. shut-off valve unit external to the target air conditioning space. Thus, it is necessary to reduce refrigerant leakage from the brazing portion brazing the stop valve on the gas side and the gas connection pipe on the outdoor side.

In this case, since the brazing portion brazing the gas side stop valve and the outdoor side gas connection pipe is provided with the lining material described above, the leakage of refrigerant from the gas side portion is reduced. brazing brazing the gas side stop valve and the outdoor side gas connection pipe, and the outdoor stop valve unit can be arranged in the air conditioning target space together with the indoor unit.

Accordingly, the degree of freedom is ensured for the arrangement of the external stop valve unit.

For the coating material, any material can be used as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be used. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be used.

An air conditioner according to an eighth aspect is the air conditioner according to the fourth or fifth aspect, in which the refrigerant gas connection pipe is provided with a relay unit including a cooling/heating switching valve that switches individually a corresponding one of the plurality of indoor heat exchangers to function as an evaporator or radiator of the refrigerant. The control unit causes the indoor expansion valve and the cooling/heating switching valve serving as the gas side stop valve to close in accordance with information from the refrigerant leak detecting means when the refrigerant he escapes.

In this case, as described above, the cooling/heating switching valve of the relay unit used to individually switch the operating state of one of the corresponding indoor units (that is, the state in which the heat exchanger indoor heat exchanger works as the evaporator of the refrigerant and the state in which the indoor heat exchanger works as the radiator of the refrigerant) is also used as the stop valve of the gas side. As long as the cooling/heating switching valve can also be used as a stop valve on the gas side of the indoor unit, the increase in cost and size of the indoor unit can be suppressed by that amount.

Accordingly, the refrigerant shutdown function for the situation that refrigerant leaks from the indoor unit can be added while reducing the increase in cost and size of the indoor unit due to the provision of the valve. shut-off on the gas side of the indoor unit as much as possible.

An air conditioner according to a ninth aspect is the air conditioner according to the eighth aspect, in which the cooling/heating switching valve is connected by brazing to an indoor side gas connecting pipe which is connected to a refrigerant gas connection pipe portion on an indoor unit side, and an outdoor side gas connection pipe which is connected to a refrigerant gas connection pipe portion on an indoor unit side. Exterior. A welding portion that welds the cooling/heating switching valve and the outdoor side gas connection pipe is also provided with a coating material.

In the relay unit, the cooling/heating switching valve is connected to the gas connection pipe connected to the refrigerant gas connection pipe (the indoor side gas connection pipe and the indoor side gas connection pipe). outer side) by brazing. Because of this, when the relay unit is arranged in the air conditioning target space together with the indoor unit, the brazing portion that brazes the cooling/heating switching valve and the side gas connection pipe exterior may corrode and coolant may leak from the corroded portion. In this case, when the relay unit is arranged in the air conditioning target space together with the indoor unit, if the refrigerant leaks from the brazing portion brazing the cooling/heating switching valve and the piping outdoor side gas connection pipe, refrigerant is continuously supplied from the refrigerant gas connection pipe to the brazing portion, even though the cooling/heating switching valve is closed, and the refrigerant can continuously leak from the gas connection unit. relay to the air conditioning target space. Thus, it is necessary to reduce refrigerant leakage from the brazing portion brazing the cooling/heating switching valve and the outdoor side gas connection pipe.

In this case, since the brazing portion brazing the cooling/heating switching valve and the outdoor side gas connection pipe is provided with the lining material described above, refrigerant leakage from the brazing portion is reduced. brazing brazing the cooling/heating switching valve and the outdoor side gas connection pipe, and the relay unit can be arranged in the air conditioning target space together with the indoor unit.

Consequently, the degree of freedom is ensured for the arrangement of the relay unit.

For the coating material, any material can be used as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be used. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be used.

An air conditioner according to a tenth aspect is the air conditioner according to any one of the first to fifth aspects, in which the stop valve on the gas side is provided in the indoor unit. The indoor unit includes a heat exchanger-side indoor refrigerant gas pipe connecting the gas side of the indoor heat exchanger to the gas-side stop valve, and an air-side refrigerant gas indoor pipe. connection connecting the gas side stop valve to the refrigerant gas connection pipe. The gas side stop valve is connected to the connection side indoor refrigerant gas pipe by brazing. A welding portion that welds the stop valve on the gas side and the indoor refrigerant gas pipe on the connection side is also provided with a coating material.

To add the refrigerant stop function for the situation where refrigerant leaks from the indoor unit, the indoor expansion valve of the indoor unit can also be used as a stop valve on the liquid side, and the valve Gas side shutoff can be provided on the indoor unit. In this case, the connection side indoor refrigerant gas pipe connecting the gas side stop valve with the refrigerant gas connection pipe is connected to the gas side stop valve by brazing. Due to this, the brazing portion brazing the stop valve of the gas side and the indoor refrigerant gas pipe of the connection side may corrode and refrigerant may leak from the corroded portion. When refrigerant leaks from the brazing portion brazing the gas side stop valve and the connection side indoor refrigerant gas pipe, refrigerant is continuously supplied from the refrigerant gas connection pipe to the connection side welding, even if the gas side shutoff valve is closed. The refrigerant may continuously leak from the indoor unit to the target air conditioning space. Thus, it is necessary to reduce refrigerant leakage from the brazing portion brazing the stop valve on the gas side and the indoor refrigerant gas pipe on the connection side.

In this case, since the brazing portion brazing the gas-side stop valve and the connection-side indoor refrigerant gas pipe is provided with the above-described lining material, leakage of the refrigerant from the connection side is reduced. brazing portion brazing the stop valve of the gas side and the indoor refrigerant gas pipe of the connection side.

Therefore, the stop valve provided in the indoor unit is provided only on the gas side, and the refrigerant stop function can be added for the situation that refrigerant leaks from the indoor unit.

For the coating material, any material can be used as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be used. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be used.

An indoor unit according to an eleventh aspect is an indoor unit connected to an outdoor unit through a refrigerant liquid connection pipe and a refrigerant gas connection pipe, arranged in an air conditioning target space and including an indoor heat exchanger, an indoor expansion valve, an indoor refrigerant liquid pipe of the heat exchange side and an indoor refrigerant liquid pipe of the connection side. The indoor heat exchanger performs heat exchange between a refrigerant, which circulates between the indoor unit and the outdoor unit through the refrigerant liquid connection pipe and the refrigerant gas connection pipe, and an air, that is sent to the target air conditioning space. The internal expansion valve decompresses the refrigerant. The heat exchanger side indoor refrigerant liquid pipe connects a liquid side of the indoor heat exchanger to the indoor expansion valve. The connection side indoor refrigerant liquid pipe connects the indoor expansion valve to the refrigerant liquid connection pipe. The indoor expansion valve is connected to the connection side indoor refrigerant liquid pipe by brazing. A brazing portion welds the indoor expansion valve and the indoor refrigerant liquid pipe of the connection side is provided with a lining material.

To add the refrigerant stop function for the situation where the refrigerant leaks from the indoor unit, providing stop valves on both the liquid side and the gas side of the indoor unit may increase the cost and the size of the indoor unit. In order to minimize the increase in cost and size of the indoor unit, it is desirable to use the indoor expansion valve also as a stop valve on the liquid side for the situation where refrigerant leaks from the indoor unit. .

In the indoor unit arranged in the air conditioning objective space, however, the connection side indoor refrigerant liquid pipe connecting the indoor expansion valve to the refrigerant liquid connection pipe is connected to the valve internal expansion by brazing. The brazing portion brazing the indoor expansion valve and the indoor refrigerant liquid pipe of the connection side may corrode and refrigerant may leak from the corroded portion. When refrigerant leaks from the brazing portion that brazes the indoor expansion valve and the indoor refrigerant liquid pipe of the connection side, refrigerant is continuously supplied from the refrigerant liquid connection pipe to the brazing portion. strong, although the indoor expansion valve closes to function as a stop valve on the liquid side of the indoor unit. The refrigerant may continuously leak from the indoor unit to the target air conditioning space. Thus, it is difficult to use the indoor expansion valve also as stop valve on the liquid side of the indoor unit unless said refrigerant leakage from the brazing portion brazing the expansion valve is reduced. indoor and the indoor refrigerant liquid pipe of the connection side.

In this case, by providing the lining material on the brazing portion that welds the indoor expansion valve and the connection side indoor refrigerant liquid pipe as described above, the leakage of refrigerant from the expansion valve is reduced. brazing portion brazing the indoor expansion valve and the indoor refrigerant liquid pipe of the connection side, and the indoor expansion valve can also be used as a stop valve on the liquid side of the indoor unit . As long as the indoor expansion valve can also be used as a stop valve on the liquid side of the indoor unit, the increase in cost and size of the indoor unit can be suppressed by that amount.

Accordingly, the refrigerant shutdown function for the situation that refrigerant leaks from the indoor unit can be added while reducing the increase in cost and size of the indoor unit due to the provision of the valve. closure on the liquid side of the indoor unit as much as possible.

For the coating material, any material can be used as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be used. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be used.

An indoor unit according to a twelfth aspect is the indoor unit according to the eleventh aspect further including a gas side stop valve which is connected to the gas side of the indoor heat exchanger; a heat exchanger side indoor refrigerant gas pipe connecting the gas side of the indoor heat exchanger with the gas side stop valve; and an indoor connection side refrigerant gas pipe connecting the gas side stop valve to the connection side refrigerant gas pipe. The gas side stop valve is connected to the connection side indoor refrigerant gas pipe by brazing. A welding portion that welds the stop valve on the gas side and the indoor refrigerant gas pipe on the connection side is also provided with a coating material.

To add the refrigerant shutdown function for the situation where refrigerant leaks from the cooling unit indoor unit, the indoor expansion valve of the indoor unit can also be used as the liquid side stop valve, and the gas side stop valve can be provided in the indoor unit. In this case, the connection side indoor refrigerant gas pipe connecting the gas side stop valve with the refrigerant gas connection pipe is connected to the gas side stop valve by brazing. Due to this, the brazing portion brazing the stop valve of the gas side and the indoor refrigerant gas pipe of the connection side may corrode and refrigerant may leak from the corroded portion. When refrigerant leaks from the brazing portion brazing the gas side stop valve and the connection side indoor refrigerant gas pipe, refrigerant is continuously supplied from the refrigerant gas connection pipe to the connection side welding, even if the gas side shutoff valve is closed. The refrigerant may continuously leak from the indoor unit to the target air conditioning space. Thus, it is necessary to reduce refrigerant leakage from the brazing portion brazing the stop valve on the gas side and the indoor refrigerant gas pipe on the connection side.

In this case, since the brazing portion brazing the gas-side stop valve and the connection-side indoor refrigerant gas pipe is provided with the above-described lining material, leakage of the refrigerant from the connection side is reduced. brazing portion brazing the stop valve of the gas side and the indoor refrigerant gas pipe of the connection side.

Therefore, the stop valve provided in the indoor unit is provided only on the gas side, and the refrigerant stop function can be added for the situation that refrigerant leaks from the indoor unit.

For the coating material, any material can be used as long as the material can suppress corrosion of the brazing portion. For example, a coating material made of resin can be used. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be used.

Brief description of the drawings

<Fig. 1 > Fig. 1 is a schematic configuration diagram of an air conditioner according to a first embodiment of the present description.

<Fig. 2> Fig. 2 illustrates a refrigerant system on the periphery of an indoor unit and an external stop valve unit constituting the air conditioner according to the first embodiment of the present description.

<Fig. 3> Fig. 3 is a flowchart of an operation when a refrigerant leak occurs in the air conditioner according to the first embodiment of the present description.

<Fig. 4> Fig. 4 illustrates a refrigerant system on the periphery of an indoor unit and an external stop valve unit constituting an air conditioner according to a first modification of the first embodiment of the present description.

<Fig. 5> Fig. 5 illustrates a refrigerant system on the periphery of an indoor unit and an external stop valve unit constituting an air conditioner according to a second modification of the first embodiment of the present description.

<Fig. 6> Fig. 6 is a schematic configuration diagram of an air conditioner according to a third modification of the first embodiment of the present description.

<Fig. 7> Fig. 7 illustrates a refrigerant system at the periphery of an indoor unit constituting the air conditioner according to the third modification of the first embodiment of the present description.

<Fig. 8> Fig. 8 is a flowchart of an operation when a refrigerant leak occurs in an air conditioner according to a fourth modification of the first embodiment of the present description.

<Fig. 9 > Fig. 9 is a schematic configuration diagram of an air conditioner according to a second embodiment of the present description.

<Fig. 10> Fig. 10 illustrates a refrigerant system on the periphery of an indoor unit and a relay unit constituting the air conditioner according to the second embodiment of the present description.

<Fig. 11> Fig. 11 is a flowchart of an operation when a refrigerant leak occurs in the air conditioner according to the second embodiment of the present description.

<Fig. 12> Fig. 12 illustrates a refrigerant system on the periphery of an indoor unit and a relay unit constituting an air conditioner according to a first modification of the second embodiment of the present description.

<Fig. 13> Fig. 13 illustrates a refrigerant system on the periphery of an indoor unit and a relay unit constituting an air conditioner according to a second modification of the second embodiment of the present description.

<Fig. 14> Fig. 14 is a flowchart of an operation when a refrigerant leak occurs in an air conditioner according to a third modification of the second embodiment of the present description.

Description of embodiments

An air conditioner and an indoor unit used for air conditioning according to one embodiment of the present description are described below with reference to the drawings. It should be noted that the specific configurations of an air conditioner and an indoor unit used for air conditioning according to one embodiment of the present description are not limited to those of the following embodiments and their modifications, and may be modified within the scope of the essence of the description.

(1) First embodiment

Setting

Fig. 1 is a schematic configuration diagram of an air conditioner 1 according to a first embodiment of the present description. Fig. 2 illustrates a refrigerant system at the periphery of the indoor units 3a and 3b and the outdoor stop valve units 4a and 4b constituting the air conditioner 1 according to the first embodiment of the present description.

The air conditioner 1 is an apparatus that performs air conditioning (cooling and heating) in an air conditioning target space in a building or the like through a vapor compression refrigeration cycle. The air conditioner 1 mainly includes an outdoor unit 2; a plurality of (in this case, two) indoor units 3a and 3b connected to each other in parallel; a refrigerant liquid connection pipe 5 and a refrigerant gas connection pipe 6 connecting the outdoor unit 2 to the indoor units 3a and 3b; a plurality of (in this case, two) external stop valve units 4a and 4b provided in the refrigerant gas connection pipe 5; and a control unit 19 that controls the components of the outdoor unit 2, the indoor units 3a and 3b and the external stop valve units 4a and 4b. A vapor compression refrigerant circuit 10 of the air conditioner 1 is formed by connecting the outdoor unit 2, the plurality of indoor units 3a and 3b and the plurality of external stop valve units 4a and 4b with each other through the refrigerant liquid connection pipe 5 and the refrigerant gas connection pipe 6. The refrigerant circuit 10 is filled with a refrigerant such as R32.

connecting pipe

The refrigerant liquid connection pipe 5 mainly includes a joint pipe portion extending from the outdoor unit 2, and branch pipe portions 5a and 5b branching at a position upstream of the indoor units 3a and 3b in a plurality of (in this case, two) pieces of tubing. The refrigerant gas connecting pipe 6 mainly includes a conjoined pipe portion extending from the outdoor unit 2, the first branch pipe portions 6a and 6b branched at a position before the indoor units 3a and 3b at a plurality of (in this case, two) pipe portions and second branching pipe portions 6aa and 6bb connecting the external stop valve units 4a and 4b to the indoor units 3a and 3b.

indoor unit

The indoor units 3a and 3b are arranged in air conditioning target spaces in a building or the like. Being "arranged in air conditioning target spaces" includes a situation where the indoor units 3a and 3b are installed in the air conditioning target spaces and a situation where the indoor units 3a and 3b are not arranged in the air conditioning target spaces, but the indoor units 3a and 3b are connected to the air conditioning target spaces through air ducts or the like. The indoor units 3a and 3b are connected to the outdoor unit 2 through the refrigerant liquid connection pipe 5, the refrigerant gas connection pipe 6 and the outdoor stop valve units 4a and 4b, and constitute part of the of the refrigerant circuit 10, as previously described.

The configurations of the indoor units 3a and 3b are described below. The indoor unit 3a and the indoor unit 3b have configurations similar to each other. Therefore, only the configuration of the indoor unit 3a is described. For the configuration of the indoor unit 3b, the description of the components of the indoor unit 3b is omitted while an index "b" is applied to each component instead of the index "a", which indicates each component of the unit indoor 3a.

The indoor unit 3a mainly includes an indoor expansion valve 51a and an indoor heat exchanger 52a. Additionally, the indoor unit 3a includes an indoor refrigerant liquid pipe 53a connecting the liquid side of the indoor heat exchanger 52a to the refrigerant liquid connection pipe 5 (in this case, the branch pipe portion 5a) and an indoor refrigerant gas pipe 54a connecting the gas side of the indoor heat exchanger 52a to the refrigerant gas connection pipe 6 (in this case, the second portion of branched pipe 6aa).

The indoor expansion valve 51a is an electric expansion valve that decompresses the refrigerant. The indoor expansion valve 51a is provided in the indoor refrigerant liquid pipe 53a.

The indoor heat exchanger 52a is a heat exchanger that performs heat exchange between the refrigerant, which circulates between the indoor unit 3a and the outdoor unit 2 through the refrigerant liquid connection pipe 5 and the pipe refrigerant gas connection port 6, and indoor air, which is sent to the air conditioning target space. The indoor unit 3a includes an indoor fan 55a that sucks indoor air into the indoor unit 3a, which causes the indoor air to exchange heat with the refrigerant in the indoor heat exchanger 52a, and then sends the indoor air into the space air conditioning goal. That is, the indoor unit 3a includes the indoor fan 55a as a fan that sends the indoor air, which serves as the cooling source or heat source of the refrigerant flowing through the indoor heat exchanger 52a, to the indoor unit heat exchanger 52a. inside 52a. The indoor fan 55a is driven by an indoor fan motor 56a.

The indoor refrigerant liquid pipe 53a mainly includes a heat exchange side indoor refrigerant liquid pipe 71a connecting the liquid side of the indoor heat exchanger 52a to the indoor expansion valve 51a, and a connection side indoor refrigerant liquid 72a connecting the indoor expansion valve 51a to the refrigerant liquid connection pipe 5 (in this case, the branch pipe portion 5a). The liquid side of the indoor heat exchanger 52a is connected to the indoor refrigerant liquid pipe 71a of the heat exchange side by brazing. The indoor refrigerant liquid pipe of the heat exchange side 71a is connected to the indoor expansion valve 51a by brazing (the brazing portion is called the brazing portion 81a). The indoor expansion valve 51a is connected to the connection side indoor refrigerant liquid pipe 72a by brazing (the brazing portion is called the brazing portion 82a). The connection side indoor refrigerant liquid pipe 72a is connected to the refrigerant liquid connection pipe 5 (in this case, the branch pipe portion 5a) by mechanical pipe joint, such as a flare connection (the branch pipe portion 5a). mechanical pipe joint is called the pipe joint portion 83a). The pipe joint portion 83a is connected to the connection side indoor refrigerant liquid pipe 72a by brazing (the brazing portion is called the brazing portion 83aa). Although not illustrated here, the connection side indoor refrigerant liquid pipe 72a can be directly connected to the refrigerant liquid connection pipe 5 (in this case, the branch pipe portion 5a) by brazing without mechanical jointing of pipe such as the pipe joint portion 83a.

The brazing portion 82a that welds the indoor expansion valve 51a and the connection side indoor refrigerant liquid pipe 72a is provided with a lining material 11a. For the coating material 11a, any material can be used, as long as the material can suppress corrosion of the brazing portion 82a. For example, a coating material made of resin can be used. In particular, a water-repellent material and a heat-insulating material are suitable. For example, urethane resin can be used. The coating material 11a may be provided on the brazing portion 82a, or may also be provided on a portion other than the brazing portion 82a. For example, as illustrated in Fig. 2, the lining material 11a can be provided in a range from the indoor expansion valve 51a to the pipe joint portion 83a of the supply-side indoor refrigerant liquid pipe. connection 72a (ie, to include the brazing portion 82a and the brazing portion 83aa). When the connection side indoor refrigerant liquid pipe 72a is directly connected to the refrigerant liquid connection pipe 5 (in this case, the branch pipe portion 5a) by brazing, the lining material 11a can be provided in an interval from the indoor expansion valve 51 a to the brazing portion that welds the connection side indoor refrigerant liquid pipe 72a and the refrigerant liquid connection pipe 5 (in this case, the branch pipe portion 5a).

The gas side of the indoor heat exchanger 52a is connected to the indoor refrigerant gas pipe 54a by brazing. The indoor refrigerant gas pipe 54a is connected to the refrigerant gas connection pipe 6 (in this case, the second branch pipe portion 6aa) by mechanical pipe joint, such as a flare connection (the mechanical joint portion of pipe is called a pipe joint portion 84a). The pipe joint portion 84a is connected to the indoor refrigerant gas pipe 54a by brazing (the brazing portion is called the brazing portion 84aa). Although not illustrated here, the indoor refrigerant gas pipe 54a can be directly connected to the refrigerant gas connection pipe 6 (in this case, the second branch pipe portion 6aa) by brazing.

The indoor unit 3a is provided with a refrigerant sensor 57a which serves as a refrigerant leak detecting means for detecting refrigerant leaks. The refrigerant sensor 57a is provided in the indoor unit 3a in this case; however, it is not limited to it. The refrigerant sensor 57a can be provided, for example, in a remote controller for operating the indoor unit 3a, or in the target air conditioning space where the indoor unit 3a is arranged. The refrigerant leak detecting means may be the refrigerant sensor 57a which directly detects the refrigerant leak as described above, or alternatively, though not used in this case, the refrigerant leak detecting means may be one that estimates the presence or amount of leaked refrigerant based on the relationship between the refrigerant temperature in the indoor heat exchanger 52a and the atmospheric temperature of the indoor heat exchanger 52a.

outdoor unit

The outdoor unit 2 is arranged outside the target air conditioning space or outside the building or the like. The outdoor unit 2 is connected to the indoor units 3a and 3b through the refrigerant liquid connection pipe 5, the refrigerant gas connection pipe 6 and the external stop valve units 4a and 4b, and constitutes part of the of the refrigerant circuit 10, as previously described.

Next, a configuration of the outdoor unit 2 is described.

The outdoor unit 2 mainly includes a compressor 21 and an outdoor heat exchanger 23. Additionally, the outdoor unit 2 includes a switching mechanism 22 that changes the operating state between a radiation operating state in which the heat exchanger The outdoor heat exchanger 23 functions as a radiator of the refrigerant and an evaporative operating state in which the outdoor heat exchanger 23 functions as an evaporator of the refrigerant. The switching mechanism 22 is connected to the suction side of the compressor 21 through a suction refrigerant pipe 31. The discharge side of the compressor 21 is connected to the switching mechanism 22 through a discharge refrigerant pipe 32. The switching mechanism 22 is connected to the gas side of the outdoor heat exchanger 23 through a first outdoor refrigerant gas pipe 33. The liquid side of the outdoor heat exchanger 23 is connected to the connection pipe of refrigerant liquid 5 through an outdoor refrigerant liquid pipe 34. The connection portion of the outdoor refrigerant liquid pipe 34 with respect to the refrigerant liquid connection pipe 5 is provided with a liquid side stop valve 27. The switching mechanism 22 is connected to the refrigerant gas connecting line 6 via a second outdoor refrigerant gas line. 35. The connection portion of the second outdoor refrigerant gas pipe 35 with respect to the refrigerant gas connection pipe 6 is provided with a gas side stop valve 28. The liquid side stop valve 27 and the gas side stop valve 28 are manually opened and closed valves.

The compressor 21 is a device for compressing the refrigerant. For example, a closed-structure compressor in which a compression member (not shown) of positive displacement type, such as a rotary type or a scroll type, is rotatably driven by a compressor motor 21 a.

The switching mechanism 22 is a device that can switch the flow of refrigerant in the refrigerant circuit 10 so that when the outdoor heat exchanger 23 functions as a radiator of the refrigerant (hereinafter, the situation is called "radiation state outdoor"), the switching mechanism 22 connects the discharge side of the compressor 21 to the gas side of the outdoor heat exchanger 23 (see solid lines of the switching mechanism 22 in Fig. 1 ); and, when the outdoor heat exchanger 23 works as an evaporator of the refrigerant (hereinafter, the situation is called "outdoor evaporation state"), the switching mechanism 22 connects the suction side of the compressor 21 to the gas side of the exchanger. outdoor heat 23 (see broken lines of switching mechanism 22 in figure 1). The switching mechanism 22 is, for example, a four-way switching valve.

The outdoor heat exchanger 23 is a heat exchanger that performs the heat exchange between the outdoor air and the refrigerant, which circulates between the outdoor unit 2 and the indoor units 3a and 3b through the connection pipe of refrigerant liquid 5 and the refrigerant gas connection pipe 6. The outdoor unit 2 includes an outdoor fan 24 that sucks outdoor air into the outdoor unit 2 that causes the outdoor air to exchange heat with the refrigerant in the heat exchanger. of outdoor 23, and then discharges the outdoor air to the outside. That is, the outdoor unit 2 includes the outdoor fan 24 as a fan that sends the outdoor air, which serves as a cooling source or heat source of the refrigerant flowing through the outdoor heat exchanger 23, the outdoor heat exchanger 23. The outdoor fan 24 is driven by an outdoor fan motor 24a.

Focusing only on the compressor 21, the outdoor heat exchanger 23, the refrigerant liquid connection pipe 5, the indoor expansion valves 51a and 51b, the indoor heat exchangers 52a and 52b and the refrigerant gas connection pipe 6 , the air conditioner 1 performs an operation (cooling operation) of circulating refrigerant in the order of compressor 21, outdoor heat exchanger 23, refrigerant liquid connection pipe 5, indoor expansion valves 51a and 51b , the indoor heat exchangers 52a and 52b, the refrigerant gas connection pipe 6, and the compressor 21. Focusing only on the compressor 21, the outdoor heat exchanger 23, the refrigerant liquid connection pipe 5, the valves expansion tubes 51a and 51b, the indoor heat exchangers 52a and 52b and the refrigerant gas connection pipe 6, the air conditioner 1 performs an operation ation (heating operation) of circulating the refrigerant in the order of the compressor 21, the refrigerant gas connecting pipe 6, the indoor heat exchangers 52a and 52b, the indoor expansion valves 51a and 51b, the connecting pipe refrigerant liquid 5, the outdoor heat exchanger 23 and the compressor 21. The switching mechanism 22 switches to the outdoor radiation state in the cooling operation, and the switching mechanism 22 changes to the outdoor evaporation state in the heating operation .

Additionally, an outdoor expansion valve 25 and a liquid pressure adjustment expansion valve 26 are provided in the outdoor refrigerant liquid pipe 34. The outdoor expansion valve 25 is an electric expansion valve that decompresses the refrigerant. in the heating operation and is provided at a portion of the outdoor refrigerant liquid pipe 34 near the liquid side of the outdoor heat exchanger 23. The liquid pressure adjusting expansion valve 26 is an electric expansion valve. which decompresses the refrigerant so that the refrigerant flowing through the refrigerant liquid connection pipe 5 is brought to a gas-liquid two-phase state in the cooling operation, and is provided in a portion of the outdoor refrigerant liquid pipe 34 near the refrigerant liquid connection pipe 5. That is, the liquid pressure adjusting expansion valve 26 is p It is provided at a portion of the outdoor refrigerant liquid pipe 34 closer to the refrigerant liquid connection pipe 5 than the outdoor expansion valve 25.

The air conditioner 1 performs a two-phase refrigerant supply by sending the refrigerant in a gas-liquid two-phase state to the refrigerant liquid connection pipe 5 through the liquid pressure adjusting expansion valve 26 and thereby sending the refrigerant from outdoor unit 2 to indoor units 3a and 3b in cooling operation.

Also, a refrigerant return pipe 41 is connected to the outdoor refrigerant liquid pipe 34, and a refrigerant cooler 45 is provided. The refrigerant return pipe 41 is a refrigerant pipe that branches part of the refrigerant flowing into through the outdoor refrigerant liquid pipe 34 and sends the refrigerant to the compressor 21. The refrigerant cooler 45 is a heat exchanger that cools the refrigerant flowing through a portion of the outdoor refrigerant liquid pipe 34 closer of the outdoor heat exchanger 23 than the liquid pressure adjusting expansion valve 26. The outdoor expansion valve 25 is provided in a portion of the outdoor refrigerant liquid pipe 34 closer to the outdoor heat exchanger 23 than the refrigerant cooler 45. The liquid pressure adjusting expansion valve 26 is provided in a portion of the l pipeline. outdoor refrigerant liquid 34 closer to the refrigerant liquid connection pipe 5 than the portion to which the refrigerant cooler 45 is connected (in this case, between the refrigerant cooler 45 and the liquid side stop valve 27 ).

The refrigerant return pipe 41 is a refrigerant pipe that sends the branched refrigerant from the outdoor refrigerant liquid pipe 34 to the suction side of the compressor 21. The refrigerant return pipe 41 mainly includes an inlet return pipe of refrigerant return pipe 42 and a refrigerant return outlet pipe 43. The refrigerant return inlet pipe 42 is a refrigerant pipe which branches part of the refrigerant flowing through the outdoor refrigerant liquid pipe 34 from a portion between the liquid side of the outdoor heat exchanger 23 and the liquid pressure adjusting expansion valve 26 (in this case, a portion between the outdoor expansion valve 25 and the refrigerant cooler 45) and sends the refrigerant to the inlet of the refrigerant cooler 45 on the refrigerant return pipe 41 side. The refrigerant return inlet pipe 42 is p Equipped with a refrigerant return expansion valve 44 that adjusts the flow rate of the refrigerant flowing through the refrigerant cooler 45 while decompressing the refrigerant flowing through the refrigerant return pipe 41. The refrigerant return expansion valve refrigerant 44 is an electric expansion valve. The refrigerant return outlet pipe 43 is a refrigerant pipe that sends refrigerant from the refrigerant cooler outlet 45 on the refrigerant return pipe 41 side to the suction refrigerant pipe 31. The refrigerant cooler 45 cools the refrigerant flowing through the outdoor refrigerant liquid pipe 34 using the refrigerant flowing through the refrigerant return pipe 41.

The outdoor unit 2 is provided with various sensors. More specifically, the outdoor unit 2 is provided with a discharge pressure sensor 36 that detects a pressure (discharge pressure Pd) of the refrigerant discharged from the compressor 21. Additionally, the outdoor unit 2 is provided with a pressure sensor outdoor heat exchange liquid side 37 which detects a temperature Tol (outdoor heat exchange outlet temperature Tol) of the refrigerant in the liquid side of the outdoor heat exchanger 23, and is provided with a pipe temperature sensor valve 38 detecting a temperature (liquid pipe temperature Tlp) of the refrigerant in a part of the outdoor refrigerant liquid pipe 34 between the refrigerant cooler 45 and the liquid pressure adjusting expansion valve 26.

External stop valve unit

The external stop valve units 4a and 4b are arranged in the building or the like. In this case, the outdoor stop valve units 4a and 4b are arranged outside the air conditioning target spaces unlike the indoor units 3a and 3b. The external stop valve units 4a and 4b, together with the refrigerant gas connection pipe 6, are provided between the indoor units 3a and 3b and the outdoor unit 2, and are part of the refrigerant circuit 10.

The configurations of the external stop valve units 4a and 4b are described below. The external stop valve unit 4a and the external stop valve unit 4b have configurations similar to each other. Therefore, only the configuration of the external stop valve unit 4a is described. For the configuration of the external stop valve unit 4b, the description of the components of the stop valve unit is omitted external stop valve unit 4b while an index "b" is applied to each component instead of the index "a", which indicates each component of the external stop valve unit 4a.

The external stop valve unit 4a is provided in the refrigerant gas connection pipe 6 and mainly includes a gas side stop valve 58a. Additionally, the external stop valve unit 4a includes a gas connection pipe 62a which is connected to the first branch pipe portion 6a, which is a portion of the refrigerant gas connection pipe 6 on the side of the outdoor unit 2, and which is connected to the second branch pipe portion 6aa, which is a portion of the refrigerant gas connection pipe 6 on the indoor unit 3a side.

The gas side stop valve 58a is an electric expansion valve that stops the flow of refrigerant between the indoor unit 3a and the outdoor unit 2 through the refrigerant gas connection pipe 6. The stop valve gas side closure 58a is provided in the gas connection pipe 62a. That is, the gas side stop valve 58a is connected to the gas side of the indoor heat exchanger 52a through the indoor refrigerant gas pipe 54a of the indoor unit 3a, the second branch pipe portion 6aa of the refrigerant gas connection pipe 6, and the gas connection pipe 62a of the external stop valve unit 4a. The gas side stop valve 58a may not be an electric expansion valve and may be an electromagnetic valve.

The gas connection pipe 62a mainly includes an indoor side gas connection pipe 66a which is connected to a portion of the refrigerant gas connection pipe 6 on the indoor unit side 3a (in this case, the second branch pipe portion 6aa), and an outdoor side gas connection pipe 67a which is connected to a portion of the refrigerant gas connection pipe 6 on the outdoor unit 2 side (in this case, the first branched pipe portion 6a). The gas side stop valve 58a is connected to the indoor side gas connection pipe 66a by brazing (the brazing portion is called the brazing portion 91 a). The gas side stop valve 58a is connected to the outdoor side gas connection pipe 67a by brazing (the brazing portion is called the brazing portion 92a). The indoor side gas connection pipe 66a is connected to the refrigerant gas connection pipe 6 (in this case, the second branch pipe portion 6aa) by mechanical pipe joint, such as a flare connection (the joint portion pipe mechanics is called the pipe joint portion 95a). The pipe joint portion 95a is connected to the indoor side gas connection pipe 66a by brazing (the brazing portion is called the brazing portion 95aa). Although not illustrated here, the indoor side gas connection pipe 66a can be directly connected to the refrigerant gas connection pipe 6 (in this case, the second branch pipe portion 6aa) by brazing. The outdoor side gas connection pipe 67a is connected to the refrigerant gas connection pipe 6 (in this case, the first branch pipe portion 6a) by mechanical pipe joint, such as a flare connection (the joint portion pipe mechanics is called the pipe joint portion 96a). The pipe joint portion 96a is connected to the outdoor side gas connection pipe 67a by brazing (the brazing portion is called the brazing portion 96aa). Although not illustrated here, the outdoor side gas connection pipe 67a can be directly connected to the refrigerant gas connection pipe 6 (in this case, the first branch pipe portion 6a) by brazing.

Control unit

The control unit 19 is constituted by being connected to control panels or the like (not illustrated) provided, for example, in the outdoor unit 2 and the indoor units 3a and 3b to communicate therewith. In figure 1, however, the control unit 19 is illustrated in a separate position from the outdoor unit 2, the indoor units 3a and 3b and the external stop valve units 4a and 4b for the sake of clarity in the illustration. illustration. The control unit 19 controls the components 21, 22, 24, 25, 26, 44, 51a, 51b, 55a, 55b, 58a and 58b of the air conditioner 1 (in this case, the outdoor unit 2, the air conditioner units 3a and 3b and the external stop valve units 4a and 4b), that is, it controls the entire operation of the air conditioner 1 in accordance with the detection signals of the various sensors 36, 37, 38, 57a and 57b described previously.

Operation without refrigerant leakage

The operation of the air conditioner 1 when the refrigerant does not leak is described below with reference to Fig. 1. The air conditioner 1 performs the cooling operation and the heating operation. The air conditioner 1 performs a two-phase refrigerant supply by sending the refrigerant in a gas-liquid two-phase state to the refrigerant liquid connection pipe 5 through the liquid pressure adjusting expansion valve 26 provided in the refrigerant liquid pipe of 34 and therefore sends the refrigerant from the outdoor unit 2 to the indoor units 3a and 3b in cooling operation. The operation of the air conditioner 1 described below is performed by the control unit 19 which controls the components of the air conditioner 1.

cooling operation

In the cooling operation, for example, when all the indoor units 3a and 3b perform the cooling operation cooling (that is, operation in which all of the indoor heat exchangers 52a and 52b function as evaporators of the refrigerant and the outdoor heat exchanger 23 functions as a radiator of the refrigerant), the switching mechanism 22 switches to the state of outdoor radiation (the state in which the switching mechanism 22 is indicated by solid lines in Fig. 1), and the compressor 21, the outdoor fan 24 and the indoor fans 55a and 55b are driven.

Then, the high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 23 through the switching mechanism 22. The refrigerant sent to the outdoor heat exchanger 23 is condensed by cooling through heat exchange with air supplied by the outdoor fan 24 into the outdoor heat exchanger 23 which functions as a radiator of the refrigerant. The refrigerant leaves the outdoor unit 2 through the outdoor expansion valve 25, the refrigerant chiller 45, the liquid pressure adjusting expansion valve 26 and the liquid side stop valve 27.

The refrigerant leaving the outdoor unit 2 is branched off and sent to the indoor units 3a and 3b through the refrigerant liquid connection pipe 5. The refrigerant sent to the indoor units 3a and 3b is decompressed by the indoor expansion valves 51a and 51b so that it is at low pressure. The refrigerant is sent to the indoor heat exchangers 52a and 52b. The refrigerant sent to the indoor heat exchangers 52a and 52b is evaporated by heating through heat exchange with the indoor air supplied from the target air conditioning spaces by the indoor fans 55a and 55b in the indoor heat exchangers 52a. and 52b that function as the refrigerant evaporators. The refrigerant leaves the indoor units 3a and 3b. The indoor air cooled by the indoor heat exchangers 52a and 52b is sent to the air conditioning target spaces, and the air conditioning target spaces are cooled using the cooled indoor air.

The refrigerant discharged from the indoor units 3a and 3b is sent to the external stop valve units 4a and 4b through the second branch pipe portions 6aa and 6bb of the refrigerant gas connection pipe 6. The refrigerant sent to the external stop valve units 4a and 4b passes through the gas side stop valves 58a and 58b and then exits the external stop valve units 4a and 4b.

The refrigerant coming out of the external stop valve units 4a and 4b is attached to the refrigerant gas connection pipe 6 and sent to the outdoor unit 2. The refrigerant sent to the outdoor unit 2 is sucked into the compressor 21 via the gas side shutoff valve 28 and the switching mechanism 22.

In the cooling operation described above, the air conditioner 1 performs a two-phase refrigerant feeding by sending the refrigerant in a gas-liquid two-phase state to the refrigerant liquid connection pipe 5 through the liquid pressure adjusting expansion valve 26 and , therefore, sending the refrigerant from the outdoor unit 2 to the indoor units 3a and 3b. Additionally, the refrigerant flowing through the outdoor refrigerant liquid pipe 34 is cooled by the refrigerant return pipe 41 and the refrigerant cooler 45 to reduce the variation in the temperature of the liquid pipe Tlp in the portion of the outdoor refrigerant liquid pipe 34 between the refrigerant cooler 45 and the liquid pressure adjusting expansion valve 26, so that the two-phase refrigerant feeding can be performed properly.

First of all, the control unit 19 causes the liquid pressure adjusting expansion valve 26 to decompress the refrigerant so that the refrigerant flowing through the refrigerant liquid connecting pipe 5 is brought to the two-phase gas-gas state. liquid. The refrigerant decompressed by the liquid pressure adjusting expansion valve 26 is the medium pressure refrigerant which is lower than the pressure of the high pressure refrigerant and higher than the pressure of the low pressure refrigerant. The control unit 19 controls the opening degree of the liquid pressure adjusting expansion valve 26 so that a subcooling degree SCo of the refrigerant on the liquid side of the outdoor heat exchanger 23 becomes a target degree of sco subcooling More specifically, the control unit 19 derives the subcooling degree SCo of the refrigerant on the liquid side of the outdoor heat exchanger 23 from the liquid side temperature of the outdoor heat exchanger Tol. The control unit 19 obtains the degree of subcooling SCo of the refrigerant on the liquid side of the outdoor heat exchanger 23 by subtracting the outlet temperature of the outdoor heat exchanger Tol from a temperature Toc of the refrigerant, which is obtained by converting the pressure discharge Pd at a saturation temperature. The control unit 19 performs the control to increase the opening degree of the liquid pressure adjusting expansion valve 26 if the subcooling degree SCo is greater than the target subcooling degree SCot, and performs the control to decrease the degree. expansion valve 26 liquid pressure adjustment opening if the subcooling degree SCo is less than the subcooling degree target SCot. At this time, the control unit 19 performs the control to set the opening degree of the outdoor expansion valve 25 to a fully open state.

With this control, the refrigerant flowing through the refrigerant liquid connecting pipe 5 is brought into the gas-liquid two-phase state. Therefore, the refrigerant liquid connection pipe 5 is less likely to be filled with the refrigerant in a liquid state as compared to the case where the refrigerant flowing through the refrigerant liquid connection pipe 5 is in a liquid state. . The amount of refrigerant in the refrigerant liquid connecting pipe 5 can be decreased by that amount.

The control unit 19 makes the temperature (the liquid pipe temperature Tlp) of the refrigerant in the portion of the outdoor refrigerant liquid pipe 34 between the refrigerant cooler 45 and the liquid pressure adjusting expansion valve. 26 be constant cooling the refrigerant flowing through the portion of the outdoor refrigerant liquid pipe 34 closer to the outdoor heat exchanger 23 than the liquid pressure adjustment expansion valve 26 by the refrigerant cooler 45 using the refrigerant flowing through the refrigerant return pipe 41. The control unit 19 controls the opening degree of the refrigerant return expansion valve 44 so that the temperature (the temperature Tlp of the liquid pipe) of the refrigerant in the portion of the outdoor refrigerant liquid pipe 34 between the refrigerant cooler 45 and the pressure adjusting expansion valve 26 is co Invest in a target liquid pipe temperature Tlpt. More specifically, the control unit 19 performs the control to increase the opening degree of the refrigerant return expansion valve 44 if the liquid pipe temperature Tlp is higher than the target liquid pipe temperature Tlpt, and performs the control to decrease the opening degree of the refrigerant return expansion valve 44 if the liquid pipe temperature Tlp is lower than the target liquid pipe temperature Tlpt.

With the control, the temperature (the liquid pipe temperature Tlp) of the refrigerant in the portion of the outdoor refrigerant liquid pipe 34 between the refrigerant cooler 45 and the liquid pressure adjusting expansion valve 26 can be maintained. constant at the target liquid pipe temperature Tlpt. By making the temperature Tlp of the liquid pipe constant and reducing the variation, the refrigerant flowing through the refrigerant liquid connection pipe 5 after being decompressed by the liquid pressure adjusting expansion valve 26 can be kept steady. reliable in a desirable gas-liquid biphasic state.

heating operation

In the heating operation, for example, when all the indoor units 3a and 3b perform the heating operation (that is, operation in which all the indoor heat exchangers 52a and 52b function as refrigerant radiators and the heat exchanger outdoor heat 23 functions as an evaporator of the refrigerant), the switching mechanism 22 switches to the outdoor evaporation state (the state in which the switching mechanism 22 is indicated by dashed lines in Fig. 1), and the compressor 21, the outdoor fan 24 and indoor fans 55a and 55b are driven.

Then, the high-pressure refrigerant discharged from the compressor 21 leaves the outdoor unit 2 through the switching mechanism 22 and the gas side stop valve 28.

The refrigerant leaving the outdoor unit 2 is branched off and sent to the outdoor stop valve units 4a and 4b through the refrigerant gas connection pipe 6. The refrigerant sent to the outdoor stop valve units 4a and 4b passes through the gas side stop valves 58a and 58b and then exits the external stop valve units 4a and 4b.

The refrigerant discharged from the external stop valves 4a and 4b is sent to the indoor units 3a and 3b through the second branch pipe portions 6aa and 6bb of the refrigerant gas connection pipe 6. The refrigerant sent to the indoor units 3a and 3b is sent to indoor heat exchangers 52a and 52b. The high-pressure refrigerant sent to the indoor heat exchangers 52a and 52b is condensed by cooling through heat exchange with the indoor air supplied from the target air conditioning spaces by the indoor fans 55a and 55b in the heat exchangers. inner tubes 52a and 52b that function as the coolant radiators. The refrigerant leaves the indoor units 3a and 3b through the indoor expansion valves 51a and 51b. The indoor air heated by the indoor heat exchangers 52a and 52b is sent to the air conditioning target spaces, and the air conditioning target spaces are heated using the heated indoor air.

The refrigerant coming out of the indoor units 3a and 3b joins the refrigerant liquid connection pipe 5 and is sent to the outdoor unit 2. The refrigerant sent to the outdoor unit 2 is sent to the outdoor expansion valve 25 through the liquid side stop valve 27, the liquid pressure adjusting expansion valve 26 and the refrigerant cooler 45. The refrigerant sent to the outdoor expansion valve 25 is decompressed by the outdoor expansion valve 25 to be in low pressure and then sent to the outdoor heat exchanger 23. The refrigerant sent to the outdoor heat exchanger 23 is evaporated by heating through heat exchange with the outdoor air supplied by the outdoor fan 24. The refrigerant is sucked into the compressor 21 through the switching mechanism 22.

In the heating operation described above, unlike the cooling operation, the control unit 19 performs the control to set the opening degree of the liquid pressure adjusting expansion valve 26 to a fully open state. The opening degree of the refrigerant return expansion valve 44 is brought to a fully closed state to prevent the refrigerant from flowing into the refrigerant return pipe 41.

Operation with refrigerant leak

The operation of the air conditioner 1 when the refrigerant leaks is described below with reference to Figs. 1 to 3. Fig. 3 is a flowchart of an operation when a refrigerant leak occurs in the air conditioner 1 according to the first embodiment of the present description. The operation of the air conditioner 1 when a refrigerant leak occurs, which is described below, is performed by the control unit 19, which controls the components of the air conditioner 1 (the outdoor unit 2, the indoor units 3a and 3b and the external stop valve units 4a and 4b) as the operation when the refrigerant does not leak.

The air conditioner 1 is provided with the refrigerant sensors 57a and 57b serving as the refrigerant leak detecting means, as described above. When the refrigerant sensors 57a and 57b detect a refrigerant leak, the indoor expansion valves 51a and 51b and the gas side stop valves 58a and 58b are closed in accordance with the information from the refrigerant sensors 57a and 57b. Thus, the indoor units 3a and 3b can be isolated. Accordingly, the refrigerant can be prevented from flowing from the refrigerant connecting pipes 5 and 6 to the indoor units 3a and 3b. That is, when the refrigerant leaks, the indoor expansion valves 51a and 51b are also used as liquid-side stop valves and are closed together with the gas-side stop valves 58a and 58b, thus providing a stop function. refrigerant shutdown when refrigerant leaks from indoor units 3a and 3b.

More specifically, when the refrigerant sensors 57a and 57b detect a refrigerant leak (step ST1), the control unit 19 closes the indoor expansion valves 51a and 51b and the gas side stop valves 58a and 58b (step ST4 ). Additionally, when a refrigerant leak is detected in step ST1, an alarm may be given (step ST2). In addition, before the indoor expansion valves 51a and 51b and the gas side stop valves 58a and 58b are closed, the compressor 21 can be stopped (step ST3) to suppress an excessive increase in refrigerant pressure.

In this way, the indoor expansion valves 51a and 51b and the gas side stop valves 58a and 58b are closed in accordance with information from the refrigerant sensors 57a and 57b which serve as refrigerant leak detecting means when the refrigerant leaks. In this way, the refrigerant is prevented from flowing from the refrigerant connection pipes 5 and 6 to the indoor units 3a and 3b, and the increase in concentration of the refrigerant in the target spaces of air conditioning can be suppressed.

Features

The air conditioner 1 and the indoor units 3a and 3b according to this embodiment have the following features.

To add the refrigerant stop function for the situation where refrigerant leaks from indoor units 3a and 3b, provide stop valves on both liquid side and gas side of indoor units 3a and 3b. 3b can increase the cost and sizes of the indoor units 3a and 3b. In order to reduce the increase in cost and sizes of the indoor units 3a and 3b as much as possible, it is desirable to use the indoor expansion valves 51a and 51b also as liquid side stop valves for the situation where the refrigerant leaks from the indoor units 3a and 3b.

In the indoor units 3a and 3b arranged in the air conditioning target spaces, however, the connection side indoor refrigerant liquid pipes 72a and 72b connecting the indoor expansion valves 51a and 51b to the refrigerant liquid port 5 are connected to indoor expansion valves 51a and 51b by brazing. The brazing portions 82a and 82b brazing the indoor expansion valves 51a and 51b and the connection side indoor refrigerant liquid pipes 72a and 72b may corrode and refrigerant may leak from the corroded portions. When refrigerant leaks from the brazing portions 82a and 82b, refrigerant is continuously supplied from the refrigerant liquid connection pipe 5 to the brazing portions 82a and 82b, even though the indoor expansion valves 51a and 51b are closed. closed to function as stop valves on the liquid sides of the indoor units 3a and 3b. The refrigerant may continuously leak from the indoor units 3a and 3b to the target air conditioning spaces. Thus, it is difficult to use the indoor expansion valves 51a and 51b also as stop valves on the liquid sides of the indoor units 3a and 3b, unless said refrigerant leakage from the brazing portions is reduced. 82a and 82b.

In this case, by providing the coating materials 11a and 11b on the brazing portions 82a and 82b as described above, the leakage of refrigerant from the brazing portions 82a and 82b is reduced, and the check valves indoor expansion units 51a and 51b can also be used as stop valves on the liquid sides of indoor units 3a and 3b. As long as the indoor expansion valves 51a and 51b can also be used as the stop valves on the liquid sides of the indoor units 3a and 3b, the increase in cost and sizes of the indoor units 3a and 3b can be deleted for that amount.

Accordingly, the refrigerant shutdown function can be added for the situation where refrigerant leaks from the indoor units 3a and 3b while reducing the increase in cost and size of the indoor units 3a and 3b due to to the provision of stop valves on the liquid sides of the indoor units 3a and 3b as much as possible.

In particular, since the gas side stop valves 58a and 58b are arranged in the valve units external lock 4a and 4b located outside the indoor units 3a and 3b, as described above, the increase in the sizes of the indoor units 3a and 3b can be suppressed.

Since the outdoor unit 2 includes the liquid pressure adjustment expansion valve 26 described above, the two-phase refrigerant supply of decompressing the refrigerant to bring it to the gas-liquid two-phase state in the outdoor unit 2 and then send the refrigerant to the indoor units 3a and 3b through the refrigerant liquid connection pipe 5. In this way, the amount of refrigerant held by the whole air conditioner can be reduced by the amount by which the refrigerant flowing through the refrigerant liquid connection pipe 5 it is brought into the gas-liquid two-phase state through the two-phase refrigerant supply. However, although the amount of refrigerant retained by the whole air conditioner can be reduced to a certain degree through the two-phase refrigerant supply, when the refrigerant leaks from the indoor units 3a and 3b, the concentration of the refrigerant increases in the indoor units 3a and 3b. target air conditioning spaces where the indoor units 3a and 3b are arranged which involves leakage of the refrigerant, and the concentration may exceed its allowable value. In such a case, the two-phase refrigerant supply is occasionally not enough to counter refrigerant leakage.

In this case, by providing the coating materials 11a and 11b on the brazing portions 82a and 82b as described above, the leakage of refrigerant from the brazing portions 82a and 82b is reduced, and the check valves indoor expansion units 51a and 51b can also be used as stop valves on the liquid sides of indoor units 3a and 3b.

Therefore, even in the case that the two-phase refrigerant supply is not enough to counter the refrigerant leakage, the refrigerant shutdown function can be added for the situation that the refrigerant leaks from the 3a and 3a indoor units. 3b while reducing the increase in cost and size of the indoor units 3a and 3b due to the provision of stop valves on the liquid sides of the indoor units 3a and 3b as much as possible. The addition of the refrigerant shutdown function makes the countermeasure to refrigerant leakage sufficient.

first modification

In this embodiment, only the indoor expansion valves 51a and 51b are provided in the indoor refrigerant liquid pipes 53a and 53b, as illustrated in Fig. 2 in the indoor units 3a and 3b arranged in the air conditioning target spaces. air. Additionally, filters 73a and 73b for reducing the ingress of foreign substances, etc., to the indoor expansion valves 51a and 51b can be provided in the connection side indoor refrigerant liquid pipes 72a and 72b, as shown. illustrated in figure 4 in the indoor units 3a and 3b. The filters 73a and 73b are also connected to the indoor refrigerant liquid pipes 72a and 72b on the connection side by brazing. The connection side indoor refrigerant liquid pipes 72a and 72b include first connection side indoor refrigerant liquid pipes 74a and 74b connected to the indoor expansion valves 51a and 51b, and second connection side indoor refrigerant liquid pipes connection side 75a and 75b connected to the refrigerant liquid connection pipe 5 (in this case, the branch pipe portions 5a and 5b). The filters 73a and 73b are connected between the first connection side indoor refrigerant liquid pipes 74a and 74b and the second connection side indoor refrigerant liquid pipes 75a and 75b. The filters 73a and 73b are connected to the first connection side indoor refrigerant liquid pipes 74a and 74b and to the second connection side indoor refrigerant liquid pipes 75a and 75b by brazing (the brazing portions are called brazing portions 85a, 85b, 86a and 86b). Due to this, the brazing portions 85a, 85b, 86a and 86b may corrode and coolant may leak from the corroded portions. This makes it difficult to use the indoor expansion valves 51a and 51b as well as the stop valves on the liquid sides of the indoor units 3a and 3b, such as the brazing portions 82a and 82b that weld the expansion valves of connection side indoor refrigerant liquid pipes 72a and 72b (the first connection side indoor refrigerant liquid pipes 74a and 74b).

To address this, as illustrated in Fig. 4, the brazing portions 85a, 85b, 86a and 86b that braze the filters 73a and 73b with the first connection side indoor refrigerant liquid pipes 74a and 74b and the second connection side indoor refrigerant liquid pipes 75a and 75b are also provided with lining materials 11a, 11b, 12a and 12b. The first connecting side indoor refrigerant liquid pipes 74a and 74b, including the brazing portions 82a and 82b and the brazing portions 85a and 85b, are provided with the coating materials 11a and 11b. The second connecting side indoor refrigerant liquid pipes 75a and 75b, including the brazing portions 86a and 86b and the brazing portions 83aa and 83bb, are provided with the coating materials 12a and 12b. When the second connection side indoor refrigerant liquid pipes 75a and 75b are directly connected to the refrigerant liquid connection pipe 5 (in this case, the branch pipe portion 5a) by brazing, the lining materials 12a and 12b can be provided to include the brazing portions brazing the second connection side indoor refrigerant liquid pipes 75a and 75b and the refrigerant liquid connection pipe 5 (in this case, the branch pipe portion 5a). The manner of providing the coating materials is not limited to the above. A coating material may be provided on each of the brazing portions 82a, 82b, 85a, 85b, 86a, 86b, 83aa, and 83bb, or they may be provided together in all brazing portions 82a, 82b, 85a, 85b, 86a, 86b, 83aa and 83bb including filters 73a and 73b. Accordingly, leakage of the refrigerant from the brazing portions 85a, 85b, 86a and 86b is suppressed, the filters 73a and 73b are brazed with the first connection side indoor refrigerant liquid pipes 74a and 74b and the second connection side refrigerant pipes. connection side indoor refrigerant liquid 75a and 75b, so that the indoor expansion valves 51a and 51b can also be used as stop valves on the liquid sides of the indoor units 3a and 3b.

Even in the case that the filters 73a and 73b are provided in the connection side indoor refrigerant liquid pipes 72a and 72b, the refrigerant shutdown function can be added for the situation that refrigerant leaks from the indoor units 3a and 3b while reducing the increase in cost and size of the indoor units 3a and 3b due to the provision of stop valves on the liquid sides of the indoor units 3a and 3b as much as possible .

second modification

In the external stop valve units 4a and 4b, the gas side stop valves 58a and 58b are connected to the gas connection pipes 62a and 62b connected to the refrigerant gas connection pipe 6 (the connection pipes inner side gas pipes 66a and 66b and outer side gas connection pipes 67a and 67b) by brazing. Due to this, the brazing portions 92a and 92b brazing the gas side stop valves 58a and 58b and the outdoor side gas connection pipes 67a and 67b may corrode and refrigerant may leak from the corroded portions. In the above-described embodiment and the first modification, however, the external stop valve units 4a and 4b are arranged outside the air conditioning target spaces. Therefore, even when the refrigerant leaks from the brazing portions 92a and 92b, the refrigerant hardly leaks into the target spaces of the air conditioning. On the contrary, when the outdoor stop valve units 4a and 4b are arranged in the target air conditioning spaces together with the indoor units 3a and 3b, if refrigerant leaks from the brazing portions 92a and 92b, refrigerant is continuously supplied from the refrigerant gas connection pipe 6 to the welding portions 92a and 92b, even though the gas side stop valves 58a and 58b are closed, and refrigerant can continuously leak from the gas side stop valve units. external closures 4a and 4b to the target air conditioning spaces. Thus, it is required to reduce refrigerant leakage from the brazing portions 92a and 92b.

To address this, as illustrated in Fig. 5, the brazing portions 92a and 92b that braze the gas side stop valves 58a and 58b and the outdoor side gas connection pipes 67a and 67b are also provided with coating materials 13a and 13b. The coating materials 13a and 13b may be provided only in the brazing portions 92a and 92b, or may also be provided in a portion other than the brazing portions 92a and 92b. For example, as illustrated in Fig. 5, the lining materials 13a and 13b can be provided in a range from the gas side stop valves 58a and 58b to the pipe joint portions 96a and 96b of the gas pipes. outer side gas connection 67a and 67b (ie, to include brazing portions 92a and 92b and brazing portions 96aa and 96bb). When the outdoor side gas connection pipes 67a and 67b are directly connected to the refrigerant gas connection pipe 6 (in this case, the first branch pipe portions 6a and 6b) by brazing, the lining materials 13a and 13b can be provided in a range from the gas side stop valves 58a and 58b to the brazing portions that weld the outdoor side gas connection pipes 67a and 67b and the refrigerant gas connection pipe 6 (in in this case, the first branched pipe portions 6a and 6b). Consequently, the leakage of the refrigerant from the brazing portions 92a and 92b brazing the gas side stop valves 58a and 58b and the outdoor side gas connecting pipes 67a and 67b is reduced, and the valve units The external closing units 4a and 4b can be placed in the target spaces of the air conditioning together with the indoor units 3a and 3b. Referring to Fig. 5, in the configuration of the embodiment described above (see Fig. 2) without the filters 73a and 73b, the brazing portions 92a and 92b that braze the gas side stop valves 58a and 58b and the outdoor side gas connecting pipes 67a and 67b are provided with the lining materials 13a and 13b; however, it is not limited to the above. For example, in the first modification configuration described above (see Fig. 4) with filters 73a and 73b, brazing portions 92a and 92b that braze gas side shutoff valves 58a and 58b, and inlet pipes. outer side gas connection 67a and 67b may be provided with the coating materials 13a and 13b.

Consequently, the degree of freedom is ensured for the arrangement of the external stop valve units 4a and 4b.

Third modification

In the embodiment described above and the first and second modifications, in order to add the refrigerant shutdown function for the situation that refrigerant leaks from the indoor units 3a and 3b, the indoor expansion valves 51a and 51b of the indoor units indoor units 3a and 3b are also used as liquid side stop valves. Additionally, gas side stop valves 58a and 58b are provided in external stop valve units 4a and 4b. However, to add the refrigerant stop function for the situation where refrigerant leaks from the indoor units, the gas side stop valves 58a and 58b can be provide in the indoor units 3a and 3b as illustrated in Fig. 6 instead of providing the gas side stop valves 58a and 58b in the outdoor stop valve units 4a and 4b. The indoor refrigerant gas pipes 54a and 54b mainly include heat exchange side indoor refrigerant gas pipes 76a and 76b connecting the gas sides of the indoor heat exchangers 52a and 52b to the side stop valves. pipes 58a and 58b, and the indoor refrigerant gas connection pipes 77a and 77b connecting the gas side stop valves 58a and 58b to the refrigerant gas connection pipe 6 (in this case, the pipe portions forked 6a and 6b). In this case, the heat exchange side indoor refrigerant gas pipes 76a and 76b are connected to the gas side stop valves 58a and 58b by brazing (the brazing portions are called brazing portions 87a). and 87b), and the gas side stop valves 58a and 58b are connected to the connection side indoor refrigerant gas pipes 77a and 77b by brazing (the brazing portions are called brazing portions 88a and 87b). 88b). Due to this, the brazing portions 88a and 88b which braze the gas side stop valves 58a and 58b and the connection side indoor refrigerant gas pipes 77a and 77b may be corroded and refrigerant may leak from the portions. corroded When the refrigerant leaks from the brazing portions 88a and 88b, the refrigerant is continuously supplied from the refrigerant gas connection pipe 6 to the brazing portions 88a and 88b, although the gas side stop valves 58a and 88b 58b are closed. The refrigerant may continuously leak from the indoor units 3a and 3b to the target air conditioning spaces. Thus, it is required to reduce refrigerant leakage from the brazing portions 88a and 88b.

To address this, as illustrated in Fig. 7, the brazing portions 88a and 88b that braze the gas side stop valves 58a and 58b and the connection side indoor refrigerant gas pipes 77a and 77b are provided. of coating materials 15a and 15b. The coating materials 15a and 15b may be provided only in the brazing portions 88a and 88b, or they may also be provided in a portion other than the brazing portions 88a and 88b. For example, as illustrated in Fig. 7, the lining materials 15a and 15b can be provided in a range from the gas side stop valves 58a and 58b to the pipe joint portions 84a and 84b of the gas pipes. connection side indoor refrigerant gas 77a and 77b (ie, to include the brazing portions 88a and 88b and the brazing portions 84aa and 84bb). When the connection side indoor refrigerant gas pipes 77a and 77b are directly connected to the refrigerant gas connection pipe 6 (in this case, the branch pipe portions 6a and 6b) by brazing, the lining materials 15a and 15b can be provided in a range from the gas side stop valves 58a and 58b to the brazing portions that weld the connection side indoor refrigerant gas pipes 77a and 77b and the refrigerant gas connection pipe. 6 (in this case, the branched pipe portions 6a and 6b). Accordingly, leakage of the refrigerant from the brazing portions 88a and 88b which braze the gas side stop valves 58a and 58b and the connection side indoor refrigerant gas pipes 77a and 77b is reduced. Referring to Fig. 7, in the configuration of the embodiment described above (see Fig. 2) without the filters 73a and 73b, the gas side stop valves 58a and 58b are provided in the indoor units 3a and 3b, and the brazing portions 88a and 88b weld the gas side stop valves 58a and 58b and the connection side indoor refrigerant gas pipes 77a and 77b are provided with the lining materials 15a and 15b; however, it is not limited to the above. For example, in the configuration of the first modification described above (see Fig. 4) with the filters 73a and 73b, the gas side stop valves 58a and 58b can be provided in the indoor unit 3a and 3b, and the portions The brazing pipes 88a and 88b braze the gas side stop valves 58a and 58b and the connection side indoor refrigerant gas pipes 77a and 77b may be provided with the lining materials 15a and 15b.

Therefore, the stop valves provided in the indoor units 3a and 3b are provided only on the gas side, and the refrigerant stop function can be added for the situation that refrigerant leaks from the indoor units. 3a and 3b.

fourth modification

In the embodiment described above and the first to third modifications, as illustrated in Fig. 3, when the refrigerant sensors 57a and 57b detect a refrigerant leak, all the indoor expansion valves 51a and 51b and the stop valves of the gas side 58a and 58b are closed and the compressor 21 is stopped in accordance with the information from the refrigerant sensors 57a and 57b. Accordingly, the circulation of the refrigerant in the refrigerant circuit 10 is stopped, and the cooling operation or the heating operation is stopped not only in the indoor unit in which the refrigerant is leaked, but also in the indoor unit in which the refrigerant does not leak.

It is desirable that only the indoor unit in which the refrigerant leakage occurs is isolated, while the indoor unit in which the refrigerant leakage does not occur can continue the cooling operation or the heating operation.

As illustrated in Fig. 8, when the refrigerant sensors 57a and 57b detect a refrigerant leak (step ST1), the control unit 19 closes only the indoor expansion valve and the gas side stop valve corresponding to the indoor unit in which the refrigerant is leaked between a plurality of indoor units 3a and 3b (step ST5). Then, by continuing the circulation of the refrigerant in the refrigerant circuit 10 without stopping the compressor 21, the cooling operation or the heating operation of the indoor unit is continued. in which there is no refrigerant leakage (step ST6).

When refrigerant leaks from the indoor units 3a and 3b, only the indoor unit in which refrigerant leakage occurs is isolated, while the indoor unit in which refrigerant leakage does not occur can continue the operation.

fifth modification

In the embodiment described above and the first and second modifications, when the gas side stop valves 58a and 58b are provided, the external stop valve units 4a and 4b corresponding to the indoor units 3a and 3b are provided. However, it is not limited to it. For example, an external stop valve unit in which the external stop valve units 4a and 4b can be integrated, that is, an external stop valve unit including both gas side stop valves 58a can be used and 58b.

(2) Second embodiment

Setting

Fig. 9 is a schematic configuration diagram of an air conditioner 1 according to a second embodiment of the present description. Fig. 10 illustrates a refrigerant system on the periphery of the indoor units 3a, 3b, 3c, and 3d and the relay units 4a, 4b, 4c, and 4d constituting the air conditioner 1 according to the second embodiment of the present description. .

The air conditioner 1 is an apparatus that performs air conditioning (cooling and heating) in an air conditioning target space in a building or the like through a vapor compression refrigeration cycle. The air conditioner 1 mainly includes an outdoor unit 2; a plurality of (in this case, four) indoor units 3a, 3b, 3c and 3d connected to each other in parallel; relay units 4a, 4b, 4c and 4d respectively connected to indoor units 3a, 3b, 3c and 3d; a refrigerant liquid connection pipe 5 and a refrigerant gas connection pipe 6 connecting the outdoor unit 2 to the indoor units 3a, 3b, 3c and 3d through the relay units 4a, 4b, 4c and 4d ; and a control unit 19 that controls the components of the outdoor unit 2, the indoor units 3a, 3b, 3c and 3d and the relay units 4a, 4b, 4c and 4d. A vapor compression refrigerant circuit 10 of the air conditioner 1 is formed by connecting the outdoor unit 2, the plurality of indoor units 3a, 3b, 3c and 3d, the plurality of relay units 4a, 4b, 4c and 4d , the refrigerant liquid connection pipe 5 and the refrigerant gas connection pipe 6. The refrigerant circuit 10 is filled with a refrigerant such as R32. In the air conditioner 1, the indoor units 3a, 3b, 3c and 3d can individually perform the cooling operation or the heating operation using the relay units 4a, 4b, 4c and 4d. By sending refrigerant from the indoor unit performing heating operation to the indoor unit performing cooling operation, heat is recovered between the indoor units (in this case, mixed heating and cooling operation in which cooling operation and heating operation can be performed simultaneously).

connecting pipe

The refrigerant liquid connection pipe 5 mainly includes a joint pipe portion extending from the outdoor unit 2, first branch pipe portions 5a, 5b, 5c and 5d branched at a position before the relay units 4a, 4b , 4c, and 4d in a plurality of (in this case, four) pipe portions and second branched pipe portions 5aa, 5bb, 5cc and 5dd connecting the relay units 4a, 4b, 4c and 4d to the indoor units 3a, 3b, 3c and 3d.

The refrigerant gas connection pipe 6 mainly includes a high/low pressure refrigerant gas connection pipe 7, a low pressure refrigerant gas connection pipe 8 and branch pipe portions 6a, 6b, 6c and 6d connecting the relay units 4a, 4b, 4c and 4d to indoor units 3a, 3b, 3c and 3d. The high/low pressure refrigerant gas connection pipe 7 is a refrigerant gas connection pipe that can change the connection to the discharge side or suction side of a compressor 21 (described later), and includes a portion of joint pipe extending from the outdoor unit 2, and a plurality of (in this case, four) branch pipe portions 7a, 7b, 7c and 7d branched at a position before the relay units 4a, 4b, 4c and 4d. The low-pressure refrigerant gas connection pipe 8 is a refrigerant gas connection pipe connected to the suction side of the compressor 21 (described later), and includes a joint pipe portion extending from the outdoor unit 2 and branch pipe portions 8a, 8b, 8c and 8d branched at a position before the relay units 4a, 4b, 4c, and 4d into a plurality of (here four) pipe portions. In this way, since the refrigerant gas connection pipe 6 includes the high/low pressure refrigerant gas connection pipe 7 and the low pressure refrigerant gas connection pipe 8, the configuration includes three connection pipes including the refrigerant liquid connection pipe 5 (ie, three-pipe configuration).

indoor unit

The indoor units 3a, 3b, 3c and 3d are arranged in air conditioning target spaces in a building or similar. Being "arranged in air conditioning target spaces" includes a situation where the indoor units 3a, 3b, 3c and 3d are installed in the air conditioning target spaces and a situation where the indoor units 3a, 3b, 3c and 3d are not arranged in the air conditioning target spaces, but the indoor units 3a, 3b, 3c and 3d are connected to the air conditioning target spaces through air ducts or the like. The indoor units 3a, 3b, 3c and 3d are connected to the outdoor unit 2 through the refrigerant liquid connection pipe 5, the refrigerant gas connection pipe 6 (the high/low refrigerant gas connection pipe). low pressure 7, low pressure refrigerant gas connecting pipe 8 and branch pipe portions 6a, 6b, 6c and 6d) and relay units 4a, 4b, 4c and 4d, and constitute part of the refrigerant circuit 10, as previously described.

The configurations of the indoor units 3a, 3b, 3c and 3d are described below. The indoor unit 3a and the indoor units 3b, 3c and 3d have configurations similar to each other. Therefore, only the configuration of the indoor unit 3a is described. For configurations of indoor units 3b, 3c, and 3d, the component description of indoor units 3b, 3c, and 3d is omitted, while an index "b", "c" or "d" is applied. to each component instead of the index "a", which indicates each component of the indoor unit 3a.

The indoor unit 3a mainly includes an indoor expansion valve 51a and an indoor heat exchanger 52a. Additionally, the indoor unit 3a includes an indoor refrigerant liquid pipe 53a connecting the liquid side of the indoor heat exchanger 52a to the refrigerant liquid connection pipe 5 (in this case, the branch pipe portion 5a) and an indoor refrigerant gas pipe 54a connecting the gas side of the indoor heat exchanger 52a to the refrigerant gas connection pipe 6 (in this case, the second branch pipe portion 6aa). Indoor expansion valve 51a, indoor heat exchanger 52a, indoor refrigerant liquid pipe 53a and indoor refrigerant gas pipe 54a are similar to indoor expansion valve 51a, indoor heat exchanger 52a, the indoor refrigerant liquid pipe 53a and the indoor refrigerant gas pipe 54a of the indoor unit 3a according to the first embodiment. Thus, its description is omitted.

A brazing portion 82a that welds the indoor expansion valve 51a and the connecting side indoor refrigerant liquid pipe 72a is provided with a lining material 11a, like the indoor unit 3a according to the first embodiment.

The indoor unit 3a is provided with a refrigerant sensor 57a serving as a refrigerant leak detecting means for detecting refrigerant leaks, like the indoor unit 3a according to the first embodiment.

outdoor unit

The outdoor unit 2 is arranged outside the air conditioning target spaces or outside the building or the like. The outdoor unit 2 is connected to the indoor units 3a, 3b, 3c, and 3d through the refrigerant liquid connection pipe 5, the refrigerant gas connection pipe 6 (the high-pressure refrigerant gas connection pipe). /low pressure 7, the low pressure refrigerant gas connection pipe 8 and the branch pipe portions 6a, 6b, 6c and 6d) and the relay units 4a, 4b, 4c and 4d, and is part of the circuit of refrigerant 10, as described above.

Next, a configuration of the outdoor unit 2 is described.

The outdoor unit 2 mainly includes a compressor 21 and at least one, in this case, two outdoor heat exchangers 23a and 23b. The compressor 21 is similar to the compressor 21 of the outdoor unit 2 according to the first embodiment, and therefore its description is omitted. Additionally, the outdoor unit 2 includes switching mechanisms 22a and 22b that switch the operating state between a radiation operating state in which the outdoor heat exchangers 23a and 23b function as radiators of the refrigerant, and an operating state of evaporation in which the outdoor heat exchangers 23a and 23b function as evaporators of the refrigerant. The switching mechanisms 22a and 22b are connected to the suction side of the compressor 21 through a suction refrigerant pipe 31. The discharge side of the compressor 21 is connected to the switching mechanisms 22a and 2b through a refrigerant pipe. discharge refrigerant 32. The switching mechanism 22a is connected to the gas side ends of the outdoor heat exchangers 23a and 23b through the first outdoor refrigerant gas pipes 33a and 33b. The liquid sides of the outdoor heat exchangers 23a and 23b are connected to the refrigerant liquid connection pipe 5 through an outdoor refrigerant liquid pipe 34. The connection portion of the outdoor refrigerant liquid pipe 34 with respect to the refrigerant liquid connection pipe 5, it is provided with a liquid-side stop valve 27. Additionally, the outdoor unit 2 includes a third switching mechanism 22c that switches the operation state between a state of refrigerant outlet in which the refrigerant discharged from the compressor 21 is sent to the high/low pressure refrigerant gas connection pipe 7, and a refrigerant inlet state in which the refrigerant flowing through the high/low pressure refrigerant gas connection pipe 7 high/low pressure refrigerant gas 7 is sent to the suction refrigerant pipe 31. The third switching mechanism 22c is connected to the gas connection pipe high/low pressure refrigerant 7 through a second outdoor refrigerant gas pipe 35. The third switching mechanism 22c is connected to the suction side of the compressor 21 through the suction refrigerant pipe 31. The discharge side of the compressor 21 is connected to the third mechanism 22c through the discharge refrigerant pipe 32. The connection portion of the second outdoor refrigerant gas pipe 35 with respect to the high/low pressure refrigerant gas connection pipe 7 is provided with a check valve. high/low pressure gas side shutoff 28a. The suction refrigerant pipe 31 is connected to the low-pressure refrigerant gas connection pipe 8. The connection portion of the suction refrigerant pipe 31 with respect to the low-pressure refrigerant gas connection pipe 8 is provided of a low pressure gas side stop valve 28b. The liquid side stop valve 27 and the gas side stop valves 28a and 28b are manually opened and closed valves.

The first switching mechanism 22a is a device that can switch the flow of refrigerant in the refrigerant circuit 10 so that when the first outdoor heat exchanger 23a functions as a radiator of the refrigerant (hereinafter, the situation is called "state of outdoor radiation"), the first switching mechanism 22a connects the discharge side of the compressor 21 to the gas side of the first outdoor heat exchanger 23a (see the solid lines of the first switching mechanism 22a in Fig. 9 ); and, when the first outdoor heat exchanger 23a works as an evaporator of the refrigerant (hereinafter, the situation is called "outdoor evaporation state"), the first switching mechanism 22a connects the suction side of the compressor 21 to the gas side. of the first outdoor heat exchanger 23a (see broken lines of the switching mechanism 22a in Fig. 9). The first switching mechanism 22a is, for example, a four-way switching valve. The second switching mechanism 22b is a device that can switch the flow of refrigerant in the refrigerant circuit 10 so that when the second outdoor heat exchanger 23b functions as a radiator of the refrigerant (hereinafter, the situation is called "state of outdoor radiation"), the second switching mechanism 22b connects the discharge side of the compressor 21 to the gas side of the second outdoor heat exchanger 23b (see the solid lines of the second switching mechanism 22b in Fig. 9 ); and, when the second outdoor heat exchanger 23b works as an evaporator of the refrigerant (hereinafter, the situation is called "outdoor evaporation state"), the second switching mechanism 22b connects the suction side of the compressor 21 to the gas side. of the second outdoor heat exchanger 23b (see broken lines of the switching mechanism 22 in Fig. 9). The second switching mechanism 22b is, for example, a four-way switching valve. By changing the switching states of the switching mechanisms 22a and 22b, the outdoor heat exchangers 23a and 23b can be individually switched to function as evaporators or radiators.

The first outdoor heat exchanger 23a and the second outdoor heat exchanger 23b are heat exchangers that exchange heat between the refrigerant, which circulates between the outdoor unit 2 and the indoor units 3a, 3b, 3c and 3d through of the refrigerant liquid connection pipe 5 and the refrigerant gas connection pipe 6, and the outside air. The outdoor unit 2 includes an outdoor fan 24 that sucks outdoor air into the outdoor unit 2, which causes the outdoor air to exchange heat with the refrigerant in the outdoor heat exchangers 23a and 23b, and then discharges the outdoor air. To the exterior. That is, the outdoor unit 2 includes the outdoor fan 24 as a fan that sends the outdoor air, which serves as the cooling source or heat source of the refrigerant flowing through the outdoor heat exchangers 23a and 23b, to the outdoor unit 2. outdoor heat exchangers 23a and 23b. The outdoor fan 24 is driven by an outdoor fan motor 24a.

The third switching mechanism 22c is a device that can switch the flow of the refrigerant in the refrigerant circuit 10 so that when the refrigerant discharged from the compressor 21 is sent to the high/low pressure refrigerant gas connecting pipe 7 ( Hereinafter, the situation is called "refrigerant outlet state"), the third switching mechanism 22c connects the discharge side of the compressor 21 to the high/low pressure refrigerant gas connection pipe 7 (see the broken lines of the third switching mechanism 22c in Figure 9); and, when the refrigerant flowing through the high/low pressure refrigerant gas connecting pipe 7 is sent to the suction refrigerant pipe 31 (hereinafter, the situation is called "refrigerant inlet state"), the third switch mechanism 22c connects the suction side of the compressor 21 to the high/low pressure refrigerant gas connection pipe 7 (see the solid lines of the third switch mechanism 22c in Fig. 9 ). The third switching mechanism 22c is, for example, a four-way switching valve.

Focusing on the outdoor heat exchangers 23a and 23b, the refrigerant liquid connection pipe 5, the relay units 4a, 4b, 4c and 4d and the indoor heat exchangers 52a, 52b, 52c and 52d, the air conditioner 1 performs an operation (cooling only operation and main cooling operation) of circulating the refrigerant from the outdoor heat exchangers 23a and 23b, through the refrigerant liquid connection pipe 5 and the relay units 4a, 4b , 4c and 4d, to the indoor heat exchangers 52a, 52b, 52c and 52d that function as refrigerant evaporators. Cooling-only operation is an operating state in which only the indoor heat exchangers that function as evaporators of the refrigerant (ie, the indoor units that perform the cooling operation) exist. The main cooling operation is an operation state in which both the indoor heat exchanger that functions as the evaporator of the refrigerant and the indoor heat exchanger that functions as the radiator of the refrigerant (that is, the indoor unit that performs the heating operation) are mixed; however, the load on the evaporative side (ie, cooling load) is relatively large as a whole. Focusing on the compressor 21, the refrigerant gas connection pipe 6, the relay units 4a, 4b, 4c, and 4d, and the indoor heat exchangers 52a, 52b, 52c, and 52d, the air conditioner 1 performs an operation ( heating-only operation and main heating) of circulating the refrigerant from the compressor 21, through the refrigerant gas connection pipe 6 and the relay units 4a, 4b, 4c and 4d, to the indoor heat exchangers 52a, 52b, 52c and 52d that function as coolant radiators. The heating-only operation is an operation state in which only the indoor heat exchangers that function as radiators of the refrigerant (ie, the indoor units that perform the heating operation) exist. The main heating operation is an operation state in which both the indoor heat exchanger working as a radiator of the refrigerant and the indoor heat exchanger working as an evaporator of the refrigerant are mixed; however, the load on the radiation side (ie, heating load) is relatively large as a whole. In the cooling only operation and the main cooling operation, at least one of the switching mechanisms 22a and 22b is switched to the outdoor radiation state. In this state, the outdoor heat exchangers 23a and 23b function as radiators of the refrigerant as a whole, and the refrigerant flows from the outdoor unit 2 to the indoor units 3a, 3b, 3c and 3d through the cooling pipe. coolant connection 5 and relay units 4a, 4b, 4c and 4d. In the heating only operation and the main heating operation, at least one of the switching mechanisms 22a and 22b switches to the outdoor evaporation state and the third switching mechanism 22c switches to the refrigerant output state. In this state, the outdoor heat exchangers 23a and 23b function as evaporators of the refrigerant as a whole, and the refrigerant flows from the indoor units 3a, 3b, 3c and 3d to the outdoor unit 2 through the air pipe. coolant connection 5 and relay units 4a, 4b, 4c and 4d.

Additionally, outdoor expansion valves 25a and 25b and a liquid pressure adjustment expansion valve 26 are provided in the outdoor refrigerant liquid pipe 34. Outdoor expansion valves 25a and 25b are expansion valves electrical decompressing refrigerant in heating only operation and main heating operation, and are provided in portions of the outdoor refrigerant liquid pipe 34 near the liquid sides of the outdoor heat exchangers 23a and 23b. The liquid pressure adjustment expansion valve 26 is an electric expansion valve that decompresses the refrigerant so that the refrigerant flowing through the refrigerant liquid connection pipe 5 is brought to a gas-liquid two-phase state in operation. cooling-only and cooling-main operation, and is provided at a portion of the outdoor refrigerant liquid pipe 34 near the refrigerant liquid connection pipe 5. That is, the liquid pressure adjusting expansion valve 26 is provided at a portion of the outdoor refrigerant liquid pipe 34 closer to the refrigerant liquid connection pipe 5 than the outdoor expansion valves 25a and 25b.

The air conditioner 1 performs a two-phase refrigerant supply by sending the refrigerant in a gas-liquid two-phase state to the refrigerant liquid connection pipe 5 through the liquid pressure adjusting expansion valve 26 and thereby sending the refrigerant from outdoor unit 2 to indoor units 3a, 3b, 3c and 3d in cooling only operation and cooling main operation.

Also, a refrigerant return pipe 41 is connected to the outdoor refrigerant liquid pipe 34, and a refrigerant cooler 45 is provided. The refrigerant return pipe 41 and the refrigerant cooler 45 are similar to the return pipe. of the refrigerant 41 and the refrigerant cooler 45 of the outdoor unit 2 according to the first embodiment, and therefore their description is omitted.

The outdoor unit 2 is provided with various sensors. More specifically, the outdoor unit 2 is provided with a discharge pressure sensor 36 that detects a pressure (discharge pressure Pd) of the refrigerant discharged from the compressor 21. Additionally, the outdoor unit 2 is provided with sensors on the side outdoor heat exchange liquid tanks 37a and 37b that detect temperatures Tol (outdoor heat exchange outlet temperatures Tol) of the refrigerant in the liquid sides of the outdoor heat exchangers 23a and 23b, and is provided with a temperature sensor. liquid pipe temperature 38 detecting a temperature (liquid pipe temperature Tlp) of the refrigerant in a part of the outdoor refrigerant liquid pipe 34 between the refrigerant cooler 45 and the liquid pressure adjusting expansion valve 26 .

relay unit

The relay units 4a, 4b, 4c and 4d are arranged in the building or the like. In this case, the relay units 4a, 4b, 4c and 4d are arranged outside the air conditioning target spaces unlike the indoor units 3a, 3b, 3c and 3d. The relay units 4a, 4b, 4c and 4d are connected between the indoor units 3a, 3b, 3c and 3d and the outdoor unit 2, together with the refrigerant liquid connection pipe 5, the refrigerant gas connection pipe 6 (the high/low pressure refrigerant gas connection pipe 7, the low pressure refrigerant gas connection pipe 8 and the branch pipe portions 6a, 6b, 6c and 6d), and are part of the refrigerant circuit 10.

The configurations of the relay units 4a, 4b, 4c and 4d are described below. Relay unit 4a and relay units 4b, 4c and 4d have configurations similar to each other. Therefore, only the configuration of the relay unit 4a is described. For relay unit 4b, 4c, and 4d configurations, the component description of relay units 4b, 4c, and 4d is omitted, while an index "b", "c" or "d" applies to each component, instead of the index "a", which indicates each component of the relay unit 4a.

The relay unit 4a mainly includes a liquid connection pipe 61a and a gas connection pipe 62a.

One end of the liquid connection pipe 61a is connected to the first branch pipe portion 5a of the refrigerant liquid connection pipe 5. The other end of the liquid connection pipe 61a is connected to the second pipe portion branch 5aa of the refrigerant connection pipe 5.

The liquid connection pipe 61a is connected to a portion of the refrigerant liquid connection pipe 5 on the indoor unit 3a side (in this case, the second branch pipe portion 5aa) by mechanical pipe joint, such as a flare connection (the mechanical pipe joint portion is called the pipe joint portion 98a). The pipe joint portion 98a is connected to the outer side liquid connection pipe 61a by brazing (the brazing portion is called the brazing portion 98aa). Although not illustrated here, the outdoor side gas connection pipe 61a can be directly connected to the refrigerant gas connection pipe 5 (in this case, the second branch pipe portion 5aa) by brazing. The liquid connection pipe 61a is connected to a portion of the refrigerant liquid connection pipe 5 on the outdoor unit 2 side (in this case, the first branch pipe portion 5a) by mechanical pipe joint, such as a flare connection (the mechanical pipe joint portion is called the pipe joint portion 99a). The pipe joint portion 99a is connected to the outer side liquid connection pipe 61a by brazing (the brazing portion is called the brazing portion 99aa). Although not illustrated here, the outdoor side gas connection pipe 61a can be directly connected to the refrigerant gas connection pipe 5 (in this case, the first branch pipe portion 5a) by brazing.

The gas connection pipe 62a includes a high pressure gas connection pipe 63a connected to the branch pipe portion 7a of the high/low pressure refrigerant gas connection pipe 7, a low pressure gas connection pipe 64a connected to the branch pipe portion 8a of the low-pressure refrigerant gas connection pipe 8, and a joint gas connection pipe 65a jointly joining the high-pressure gas connection pipe 63a and the connection pipe low pressure refrigerant gas 64a. The junction gas connection pipe 65a is connected to the branch pipe portion 6a of the refrigerant gas connection pipe 6. The high-pressure gas connection pipe 63a is provided with a first cooling/heating switching valve 58a. The low-pressure gas connection pipe 64a is provided with a second cooling/heating switching valve 59a. The first cooling/heating switching valve 58a and the second cooling/heating switching valve 59a are electric expansion valves. The first cooling/heating switching valve 58a and the second cooling/heating switching valve 59a may not be electric expansion valves and may be electromagnetic valves.

The relay unit 4a can be operated in such a way that when the indoor unit 3a performs the cooling operation, the second cooling/heating switching valve 59a opens to allow the refrigerant to flow to the liquid connection pipe 61a. through the first branch pipe portion 5a of the refrigerant liquid connection pipe 5, refrigerant is sent to the indoor unit 3a through the second branch pipe portion 5aa of the refrigerant liquid connection pipe 5, then, the refrigerant evaporated through heat exchange with indoor air in the indoor heat exchanger 52a is recovered to the branch pipe portion 8a of the low-pressure refrigerant gas connection pipe 8 through the branch pipe 6a of the refrigerant gas connection pipe 6, the joint gas connection pipe 65a and the low pressure gas connection pipe 64a. Additionally, the relay unit 4a can be operated in such a way that when the indoor unit 3a performs the heating operation, the second cooling/heating switching valve 59a is closed and the first cooling/heating switching valve 59a is closed. 58a is opened to allow refrigerant to flow into the high pressure gas connection pipe 63a and the joint gas connection pipe 65a through the branch pipe portion 7a of the high pressure refrigerant gas connection pipe/ low pressure 7, the refrigerant is sent to the indoor unit 3a through the branch pipe portion 6a of the refrigerant gas connection pipe 6, then the refrigerant irradiated through heat exchange with indoor air in the indoor heat exchanger 52a is recovered to the first branch pipe portion 5a of the refrigerant liquid connection pipe 5 through the second branch pipe portion da 5aa of the refrigerant liquid connection pipe 5 and the liquid connection pipe 61a. The first cooling/heating switching valve 58a and the second cooling/heating switching valve 59a are switched open and closed to make the indoor heat exchanger 52a function as a refrigerant evaporator or a refrigerant radiator. Not only relay unit 4a, but also relay units 4b, 4c and 4d have such a function. With the relay units 4a, 4b, 4c and 4d, the indoor heat exchangers 52a, 52b, 52c and 52d can be individually switched to function as refrigerant evaporators or refrigerant radiators.

The high pressure gas connection pipe 63a mainly includes a high pressure indoor side gas connection pipe 66a which is connected to a portion of the refrigerant gas connection pipe 6 on the indoor unit side 3a ( in this case, the branch pipe portion 6a) through the joint gas connection pipe 65a, and an outdoor side high-pressure gas connection pipe 67a which is connected to a portion of the joint connection pipe refrigerant gas 6 on the outdoor unit 2 side (in this case, the portion branch pipe 7a of high/low pressure refrigerant gas connecting pipe 7). The first cooling/heating switching valve 58a is connected to the high-pressure indoor side gas connection pipe 66a by brazing (the brazing portion is called the brazing portion 91a). The first cooling/heating switching valve 58a is connected to the high-pressure outdoor side gas connection pipe 67a by brazing (the brazing portion is called the brazing portion 92a). The low pressure gas connection pipe 64a mainly includes an indoor side low pressure gas connection pipe 68a which is connected to a portion of the refrigerant gas connection pipe 6 on the indoor unit side 3a ( in this case, the branch pipe portion 6a) through the joint gas connection pipe 65a, and an outdoor side low-pressure gas connection pipe 69a which is connected to a portion of the joint gas connection pipe refrigerant gas 6 on the outdoor unit 2 side (in this case, the branch pipe portion 8a of the low-pressure refrigerant gas connecting pipe 8). The second cooling/heating valve 59a is connected to the low-pressure indoor side gas connection pipe 68a by brazing (the brazing portion is called the brazing portion 93a). The second cooling/heating valve 59a is connected to the low-pressure outdoor side gas connection pipe 69a by brazing (the brazing portion is called the brazing portion 94a). The joint gas connection pipe 65a is connected to a portion of the refrigerant gas connection pipe 6 on the indoor unit 3a side (in this case, the branch pipe portion 6a) by mechanical pipe joint, as a flare connection (the mechanical pipe joint portion is called the pipe joint portion 95a). The pipe joint portion 95a is connected to the joint gas connection pipe 65a by brazing (the brazing portion is called the brazing portion 95aa). Although not illustrated here, the joint connection pipe 65a can be directly connected to the refrigerant gas connection pipe 6 (in this case, the branch pipe portion 6a) by brazing. The outdoor side high-pressure gas connection pipe 67a is connected to a portion of the refrigerant gas connection pipe 6 on the outdoor unit 2 side (in this case, the branch pipe portion 7a of the outdoor unit side high/low pressure refrigerant gas connection 7) by mechanical pipe joint, such as a flare connection (the mechanical pipe joint portion is called the pipe joint portion 96a). The pipe joint portion 96a is connected to the high-pressure gas connection pipe 67a by brazing (the brazing portion is called the brazing portion 96aa). Although not illustrated here, the outdoor side high-pressure gas connection pipe 67a can be directly connected to the refrigerant gas connection pipe 6 (in this case, the branch pipe portion 7a of the refrigerant gas connection pipe high/low pressure 7) by brazing. The outdoor side low-pressure gas connection pipe 69a is connected to a portion of the refrigerant gas connection pipe 6 on the outdoor unit 2 side (in this case, the branch pipe portion 8a of the outdoor unit side low-pressure refrigerant gas connection piece 8) by mechanical pipe joint, such as a flare connection (the pipe mechanical joint portion is called the pipe joint portion 97a). The pipe joint portion 97a is connected to the outdoor side low-pressure gas connection pipe 69a by brazing (the brazing portion is called the brazing portion 97aa). Although not illustrated here, the outdoor side low-pressure gas connection pipe 69a can be directly connected to the refrigerant gas connection pipe 6 (in this case, the branch pipe portion 8a of the refrigerant gas connection pipe low pressure 8) by brazing.

Control unit

The control unit 19 is constituted by being connected to control panels or the like (not illustrated) provided, for example, the outdoor unit 2, the indoor units 3a, 3b, 3c and 3d and the relay units 4a, 4b , 4c and 4d to communicate with them. In figure 9, however, the control unit 19 is illustrated in a separate position from the outdoor unit 2, the indoor units 3a, 3b, 3c and 3d and the relay units 4a, 4b, 4c and 4d for better understand the illustration. The control unit 19 controls the components 21, 22, 24, 25a, 25b, 26, 44, 51a to 51d, 55a to 55d, 58a to 58d and 59a to 59d of the air conditioner 1 (in this case, the control unit 2, the indoor units 3a, 3b, 3c and 3d and the relay units 4a, 4b, 4c and 4d), that is, it controls the entire operation of the air conditioner 1 in accordance with the detection signals from the various sensors 36, 37a, 37b, 38, 57a, 57b, 57c and 57d.

Operation without refrigerant leakage

The operation of the air conditioner 1 when the refrigerant does not leak is described below with reference to Fig. 9. The air conditioner 1 performs a cooling-only operation, a heating-only operation, a main cooling operation, and a cooling-only operation. heating main. The air conditioner 1 performs a two-phase refrigerant supply by sending the refrigerant in a gas-liquid two-phase state to the refrigerant liquid connection pipe 5 through the liquid pressure adjusting expansion valve 26 provided in the refrigerant liquid pipe of 34 and thus sends the refrigerant from the outdoor unit 2 to the indoor units 3a, 3b, 3c and 3d in cooling operation and main cooling operation. The operation of the air conditioner 1 described below is performed by the control unit 19 which controls the components of the air conditioner 1.

Cool Only Operation

In cooling only operation, for example, when all indoor units 3a, 3b, 3c and 3d perform the cooling operation (that is, operation in which all of the indoor heat exchangers 52a, 52b, 52c and 52d function as refrigerant evaporators and the outdoor heat exchangers 23a and 23b function as refrigerant radiators), the cooling mechanisms switching 22a and 22b are switched to the outdoor radiation state (the state in which the switching mechanisms 22a and 22b are indicated by solid lines in Fig. 9), and the compressor 21, outdoor fan 24 and indoor fans 55a, 55b, 55c and 55d are driven. Additionally, the third switching mechanism 22c changes to the refrigerant input state (the state in which the switching mechanism 22c is indicated by solid lines in Fig. 9), and the first cooling/heating switching valves 58a , 58b, 58c and 58d and the second cooling/heating switching valves 59a, 59b, 59c and 59d of the relay units 4a, 4b, 4c and 4d are open.

Then, the high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchangers 23a and 23b through the switching mechanisms 22a and 22b. The refrigerant sent to the outdoor heat exchangers 23a and 23b is condensed and cooled by heat exchange with the outdoor air supplied by the outdoor fan 24 in the outdoor heat exchangers 23a and 23b which function as radiators of the refrigerant. The refrigerant leaves the outdoor unit 2 through the outdoor expansion valves 25a and 25b, the refrigerant cooler 45, the liquid pressure adjusting expansion valve 26 and the liquid side stop valve 27.

The refrigerant leaving the outdoor unit 2 is branched off and sent to the relay units 4a, 4b, 4c and 4d through the refrigerant liquid connection pipe 5 (the joint pipe portion and the first few portions of the branch pipe 5a, 5b, 5c and 5d). The refrigerant sent to relay units 4a, 4b, 4c, and 4d is sent to indoor units 3a, 3b, 3c, and 3d. The refrigerant sent to the indoor units 3a, 3b, 3c, and 3d is decompressed by the indoor expansion valves 51a, 51b, 51c, and 51d, and then sent to the indoor heat exchangers 52a, 52b, 52a, and 52b. The refrigerant sent to the indoor heat exchangers 52a, 52b, 52c and 52d evaporates by being heated through heat exchange with the indoor air supplied from the air conditioning target spaces by the indoor fans 55a, 55b, 55c and 55d in the indoor heat exchangers 52a, 52b, 52c and 52d which function as evaporators of the refrigerant. The refrigerant leaves the indoor units 3a, 3b, 3c and 3d. The indoor air cooled by the indoor heat exchangers 52a, 52b, 52c and 52d is sent to the air conditioning target spaces, and the air conditioning target spaces are cooled using the cooled indoor air.

The refrigerant leaving the indoor units 3a, 3b, 3c, and 3d is sent to the relay units 4a, 4b, 4c, and 4d through the branch pipe portions 6a, 6b, 6c, and 6d of the pipe. refrigerant gas connection port 6. Refrigerant sent to relay units 4a, 4b, 4c, and 4d leaves relay units 4a, 4b, 4c, and 4d through first cooling/heating switching valves 58a, 58b, 58c and 58d and the second cooling/heating switching valves 59a, 59b, 59c and 59d.

The refrigerant coming out of the relay units 4a, 4b, 4c, and 4d is joined and sent to the outdoor unit 2 through the high/low pressure refrigerant gas connection pipe 7 (the portion of the pipe joint pipe and branch pipe parts 7a, 7b, 7c and 7d) and the low-pressure refrigerant gas connection pipe 8 (the joint pipe portion and branch pipe parts 8a, 8b, 8c and 8d). The refrigerant sent to the outdoor unit 2 is sucked to the compressor 21 through the gas side stop valves 28a and 28b and the third switching mechanism 22c.

In the cooling-only operation described above, the air conditioner 1 performs two-phase refrigerant feeding by sending the refrigerant in a gas-liquid two-phase state to the refrigerant liquid connection pipe 5 through the liquid pressure adjusting expansion valve 26 and therefore sending the refrigerant from the outdoor unit 2 to the indoor units 3a, 3b, 3c and 3d. Additionally, the refrigerant flowing through the outdoor refrigerant liquid pipe 34 is cooled by the refrigerant return pipe 41 and the refrigerant cooler 45 to reduce the variation in the temperature of the liquid pipe Tlp in the portion of the outdoor refrigerant liquid pipe 34 between the refrigerant cooler 45 and the liquid pressure adjusting expansion valve 26, so that the two-phase refrigerant feeding can be performed properly. The control content relating to the two-phase refrigerant supply is similar to the control content relating to the two-phase refrigerant supply by the air conditioner 1 according to the first embodiment, and therefore its description is omitted. With this control, the refrigerant flowing through the refrigerant liquid connecting pipe 5 is brought into the gas-liquid two-phase state. Therefore, the refrigerant liquid connection pipe 5 is less likely to be filled with the refrigerant in a liquid state as compared to the case where the refrigerant flowing through the refrigerant liquid connection pipe 5 is in a liquid state. . The amount of refrigerant in the refrigerant liquid connecting pipe 5 can be decreased by that amount. By making the temperature Tlp of the liquid pipe constant and reducing the variation, the refrigerant flowing through the refrigerant liquid connection pipe 5 after being decompressed by the liquid pressure adjusting expansion valve 26 can be kept steady. reliable in a desirable gas-liquid biphasic state.

heating only operation

In heating only operation, for example, when all indoor units 3a, 3b, 3c and 3d perform heating operation (that is, operation in which all indoor heat exchangers 52a, 52b, 52c and 52d function as radiators of the refrigerant and the outdoor heat exchangers 23a and 23b function as evaporators of the refrigerant), the switching mechanisms 22a and 22b are switched to the outdoor evaporation state (the state in which the switching mechanisms 22a and 22b are indicated by broken lines in Fig. 9), and the compressor 21, the outdoor fan 24 and the indoor fans 55a, 55b, 55c and 55d are driven. Additionally, the third switching mechanism 22c switches to the refrigerant output state (the state in which the switching mechanism 22c is indicated by dashed lines in Fig. 9), and the first cooling/heating switching valves 58a , 58b, 58c and 58d and the second cooling/heating switching valves 59a, 59b, 59c and 59d of the relay units 4a, 4b, 4c and 4d are closed.

Then, the high-pressure refrigerant discharged from the compressor 21 leaves the outdoor unit 2 through the third switching mechanism 22c and the gas side stop valve 28a.

The refrigerant coming out of the outdoor unit 2 is branched off and sent to the relay units 4a, 4b, 4c and 4d through the refrigerant gas connection pipe 6 (the joint pipe portion and the the branch pipe 7a, 7b, 7c and 7d of the high/low pressure refrigerant gas connection pipe 7). The refrigerant sent to the relay units 4a, 4b, 4c, and 4d leaves the relay units 4a, 4b, 4c, and 4d through the first cooling/heating switching valves 58a, 58b, 58c, and 58d.

The refrigerant leaving the relay units 4a, 4b, 4c, and 4d is sent to the indoor units 3a, 3b, 3c, and 3d through the branch pipe portions 6a, 6b, 6c, and 6d (the the refrigerant gas connection pipe 6 connecting the relay units 4a, 4b, 4c and 4d to the indoor units 3a, 3b, 3c and 3d). The refrigerant sent to the indoor units 3a, 3b, 3c and 3d is sent to the indoor heat exchangers 52a, 52b, 52c and 52d. The high-pressure refrigerant sent to the indoor heat exchangers 52a, 52b, 52c, and 52d is condensed upon cooling through heat exchange with the indoor air supplied from the air conditioning target spaces by the indoor fans 55a, 55b. , 55c and 55d in the indoor heat exchangers 52a, 52b, 52c and 52d which function as coolant radiators. The refrigerant is decompressed by the indoor expansion valves 51a, 51b, 51c and 51d and then leaves the indoor units 3a, 3b, 3c and 3d. The indoor air heated by the indoor heat exchangers 52a, 52b, 52c and 52d is sent to the air conditioning target spaces, and the air conditioning target spaces are heated using the heated indoor air.

The refrigerant leaving the indoor units 3a, 3b, 3c, and 3d is sent to the relay units 4a, 4b, 4c, and 4d through the second branch pipe portions 5aa, 5bb, 5cc, and 5dd (the portions of the refrigerant liquid connection pipe 5 connecting the relay units 4a, 4b, 4c and 4d to the indoor units 3a, 3b, 3c and 3d). The refrigerant sent to relay units 4a, 4b, 4c, and 4d leaves relay units 4a, 4b, 4c, and 4d.

The refrigerant coming out of the relay units 4a, 4b, 4c and 4d is joined and sent to the outdoor unit 2 through the refrigerant liquid connection pipe 5 (the joint pipe portion and the first portions of the branch pipe 5a, 5b, 5c and 5d). The refrigerant sent to the outdoor unit 2 is sent to the outdoor expansion valves 25a and 25b through the liquid side stop valve 27 and the refrigerant cooler 45. The refrigerant sent to the outdoor expansion valves 25a and 25b is decompressed by outdoor expansion valves 25a and 25b, and then sent to outdoor heat exchangers 23a and 23b. The refrigerant sent to the outdoor heat exchangers 23a and 23b is evaporated by heating through heat exchange with the outdoor air supplied by the outdoor fan 24. The refrigerant is sucked into the compressor 21 through the switching mechanisms 22a and 22b. .

In the heating-only operation described above, unlike the cooling-only operation, the control unit 19 performs the control to set the opening degree of the liquid pressure adjusting expansion valve 26 in a fully open state. Thus, the opening degree of the refrigerant return expansion valve 44 is brought to a fully closed state to prevent refrigerant from flowing into the refrigerant return pipe 41.

main cooling operation

In the main cooling operation, for example, when the indoor units 3b, 3c and 3d perform the cooling operation, the indoor unit 3a performs the heating operation (that is, operation in which the indoor heat exchangers 52b, 52c and 52d function as the refrigerant evaporators and the indoor heat exchanger 52a functions as the refrigerant radiator), and the indoor heat exchangers 23a and 23b function as the refrigerant radiators, the switching mechanisms 22a and 22b are switched to the outdoor radiation state (the state in which the switching mechanisms 22a and 22b are indicated by solid lines in Fig. 9), and the compressor 21, the outdoor fan 24 and the indoor fans 55a, 55b, 55c and 55d are driven. Additionally, the third switching mechanism 22c switches to the refrigerant output state (the state in which the switching mechanism 22c is indicated by dashed lines in Fig. 9), the first cooling/heating switching valve 58a of the relay unit 4a and the second cooling/heating switching valves 59b, 59c, and 59d of the relay units 4b, 4c, and 4d open, and the second cooling/heating switching valve 59a of the relay unit 4a , as well as the first cooling/heating switching valves 58b, 58c and 58d of the relay units 4b, 4c and 4d are closed.

Then, part of the high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchangers 23a and 23b through the switching mechanisms 22a and 22b, and the residual part of the high-pressure refrigerant leaves the outdoor unit. 2 through the third switching mechanism 22c and the gas side stop valve 28a. The refrigerant sent to the outdoor heat exchangers 23a and 23b is condensed and cooled by heat exchange with the outdoor air supplied by the outdoor fan 24 in the outdoor heat exchangers 23a and 23b which function as radiators of the refrigerant. The refrigerant leaves the outdoor unit 2 through the outdoor expansion valves 25a and 25b, the refrigerant cooler 45, the liquid pressure adjusting expansion valve 26 and the liquid side stop valve 27.

The refrigerant leaving the outdoor unit 2 through the third switching mechanism 22c, etc., is sent to the relay unit 4a through the refrigerant gas connecting pipe 6 (the joint pipe portion and the branch pipe portion 7a of the high/low pressure refrigerant gas connecting pipe 7). The refrigerant sent to the relay unit 4a leaves the relay unit 4a through the first cooling/heating switching valve 58a.

The refrigerant leaving the relay unit 4a is sent to the indoor unit 3a through the branch pipe portion 6a (the portion of the refrigerant gas connection pipe 6 connecting the relay unit 4a to the indoor unit). indoor 3a). The refrigerant sent to the indoor unit 3a is sent to the indoor heat exchanger 52a. The high-pressure refrigerant sent to the indoor heat exchanger 52a is condensed and cooled through heat exchange with the indoor air supplied from the target air conditioning space by the indoor fan 55a in the indoor heat exchanger 52a. which functions as the coolant radiator. The refrigerant is decompressed by the indoor expansion valve 51a and then leaves the indoor unit 3a. The indoor air cooled by the indoor heat exchanger 52a is sent to the air conditioning target space, and the air conditioning target space is cooled using the cooled indoor air.

The refrigerant leaving the indoor unit 3a is sent to the relay unit 4a through the second branch pipe portion 5aa (the portion of the refrigerant liquid connection pipe 5 connecting the relay unit 4a to the indoor unit). indoor 3a). The refrigerant sent to the relay unit 4a is output from the relay unit 4a.

The refrigerant leaving the relay unit 4a is sent to the joint pipe portion of the refrigerant liquid connecting pipe 5 through the first branch pipe portion 5a, and joins the refrigerant leaving the relay unit 4a. outdoor unit 2 through outdoor heat exchangers 23a and 23b. The refrigerant is branched and sent to the relay units 4b, 4c, and 4d through the first branch pipe portions 5b, 5c, and 5d of the refrigerant liquid connection pipe 5. The refrigerant sent to the relay units 4b, 4c, and 4d is output from relay units 4b, 4c, and 4d.

The refrigerant leaving the relay units 4b, 4c, and 4d is sent to the indoor units 3b, 3c, and 3d through the second branch pipe portions 5bb, 5cc, and 5dd (the connecting pipe portions of refrigerant liquid 5 connecting relay units 4b, 4c and 4d to indoor units 3b, 3c and 3d). The refrigerant sent to the indoor units 3b, 3c, and 3d is decompressed by the indoor expansion valves 51b, 51c, and 51d, and then sent to the indoor heat exchangers 52b, 52a, and 52b. The refrigerant sent to the indoor heat exchangers 52b, 52c and 52d evaporates by being heated through heat exchange with the indoor air supplied from the target air conditioning spaces by the indoor fans 55b, 55c and 55d in the indoor heat exchangers 52b, 52c and 52d that function as evaporators of the refrigerant. The refrigerant leaves the indoor units 3b, 3c and 3d. The indoor air cooled by the indoor heat exchangers 52b, 52c and 52d is sent to the air conditioning target spaces, and the air conditioning target spaces are cooled using the cooled indoor air.

The refrigerant leaving the indoor units 3b, 3c, and 3d is sent to the relay units 4b, 4c, and 4d through the branch pipe portions 6b, 6c, and 6d of the refrigerant gas connection pipe 6 The refrigerant sent to the relay units 4b, 4c, and 4d leaves the relay units 4b, 4c, and 4d through the second cooling/heating switching valves 59b, 59c, and 59d.

The refrigerant coming out of the relay units 4b, 4c, and 4d is joined and sent to the outdoor unit 2 through the low-pressure refrigerant gas connection pipe 8 (the portion of the joint pipe and the parts of the branch pipe 8b, 8c and 8d). The refrigerant sent to the outdoor unit 2 is sucked to the compressor 21 through the gas side stop valves 28a and 28b and the third switching mechanism 22c.

In the above-described main cooling operation, as a cooling-only operation, the air conditioner 1 performs two-phase refrigerant feeding by sending the refrigerant in a gas-liquid two-phase state to the refrigerant liquid connection pipe 5 through the expansion valve of liquid pressure setting 26 and thereby sending the refrigerant from the outdoor unit 2 to the indoor units 3a, 3b, 3c and 3d. Additionally, the refrigerant flowing through the outdoor refrigerant liquid pipe 34 is cooled by the refrigerant return pipe 41 and the refrigerant cooler 45 to reduce the variation in temperature. of the liquid pipe Tlp in the portion of the outdoor refrigerant liquid pipe 34 between the refrigerant cooler 45 and the liquid pressure adjusting expansion valve 26, so that the two-phase refrigerant feeding can be performed properly.

Main heating operation

In the main heating operation, for example, when the indoor units 3b, 3c and 3d perform the heating operation, the indoor unit 3a performs the cooling operation (that is, operation in which the indoor heat exchangers 52b, 52c and 52d function as the refrigerant radiators and the indoor heat exchanger 52a functions as the refrigerant evaporator), and the indoor heat exchangers 23a and 23b function as the refrigerant evaporators, the switching mechanisms 22a and 22b are switched to the outdoor evaporation state (the state in which the switching mechanisms 22a and 22b are indicated by solid lines in Fig. 9), and the compressor 21, the outdoor fan 24 and the indoor fans 55a, 55b, 55c and 55d are driven. Additionally, the third switching mechanism 22c switches to the refrigerant output state (the state in which the switching mechanism 22c is indicated by dashed lines in Fig. 9), the second cooling/heating switching valves 59b, 59c and 59d of relay units 4b, 4c and 4d are closed, and the second cooling/heating switching valve 59a of relay unit 4a, as well as the first cooling/heating switching valves 58b, 58c and 58d of relay units 4b, 4c and 4d are open.

Then, the high-pressure refrigerant discharged from the compressor 21 leaves the outdoor unit 2 through the third switching mechanism 22c and the gas side stop valve 28a.

The refrigerant coming out of the outdoor unit 2 is branched off and sent to the relay units 4b, 4c and 4d through the refrigerant gas connection pipe 6 (the joint pipe portion and the joint pipe portions branch 7b, 7c and 7d of the high/low pressure refrigerant gas connection pipe 7). The refrigerant sent to the relay units 4b, 4c, and 4d leaves the relay units 4b, 4c, and 4d through the first cooling/heating switching valves 58b, 58c, and 58d.

The refrigerant leaving the relay units 4b, 4c, and 4d is sent to the indoor units 3b, 3c, and 3d through the branch pipe portions 6b, 6c, and 6d (the gas connection pipe portions refrigerant 6 connecting relay units 4b, 4c and 4d to indoor units 3b, 3c and 3d). The refrigerant sent to the indoor units 3b, 3c and 3d is sent to the indoor heat exchangers 52b, 52c and 52d. The high-pressure refrigerant sent to the indoor heat exchangers 52b, 52c, and 52d is condensed upon cooling through heat exchange with the indoor air supplied from the air conditioning target spaces by the indoor fans 55b, 55c, and 55d. in the indoor heat exchangers 52b, 52c and 52d which function as radiators of the refrigerant. The refrigerant is decompressed by the indoor expansion valves 51b, 51c and 51d and then leaves the indoor units 3b, 3c and 3d. The indoor air heated by the indoor heat exchangers 52b, 52c and 52d is sent to the air conditioning target spaces, and the air conditioning target spaces are heated using the heated indoor air.

The refrigerant leaving the indoor units 3b, 3c, and 3d is sent to the relay units 4b, 4c, and 4d through the second branch pipe portions 5bb, 5cc, and 5dd (the connecting pipe portions of refrigerant liquid 5 connecting relay units 4b, 4c and 4d to indoor units 3b, 3c and 3d). The refrigerant sent to relay units 4b, 4c, and 4d leaves relay units 4b, 4c, and 4d.

The refrigerant coming out of the relay units 4a, 4b, 4c and 4d is joined to the joint pipe portion through the first branch pipe portions 5a, 5b, 5c and 5d of the refrigerant liquid connecting pipe 5 , part of the refrigerant is branched to the first branch pipe portion 5a and sent to the relay unit 4a, and the residual part of the refrigerant is sent to the outdoor unit 2 through the joint pipe portion of the pipe refrigerant liquid connection port 5. The refrigerant sent to relay unit 4a is output from relay unit 4a.

The refrigerant leaving the relay unit 4a is sent to the indoor unit 3a through the second branch pipe portion 5aa (the portion of the refrigerant liquid connection pipe 5 connecting the relay unit 4a to the indoor unit). indoor 3a). The refrigerant sent to the indoor units 3a is decompressed by the indoor expansion valve 51a and then sent to the indoor heat exchanger 52a. The refrigerant sent to the indoor heat exchanger 52a is evaporated by heating through heat exchange with the indoor air supplied from the target air conditioning space by the indoor fan 55a in the indoor heat exchanger 52a working as an evaporator. of the refrigerant. The refrigerant leaves the indoor unit 3a. The indoor air cooled by the indoor heat exchanger 52a is sent to the air conditioning target space, and the air conditioning target space is cooled using the cooled indoor air.

The refrigerant leaving the indoor unit 3a is sent to the relay unit 4a through the branch pipe portion 6a of the refrigerant gas connecting pipe 6. The refrigerant sent to the relay unit 4a leaves the unit relay 4a through the second cooling/heating switching valve 59a.

The refrigerant coming out of the relay unit 4a is sent to the outdoor unit 2 through the connection pipe low-pressure refrigerant gas pipe 8 (the joint pipe portion and the branch pipe portion 8a). The refrigerant sent to the outdoor unit 2 through the joint pipe portion of the refrigerant liquid connection pipe 5 is sent to the outdoor expansion valves 25a and 25b through the outdoor side stop valve. 27, the liquid pressure adjusting expansion valve 26 and the refrigerant cooler 45. The refrigerant sent to the outdoor expansion valves 25a and 25b is decompressed by the outdoor expansion valves 25a and 25b, and then sent to the outdoor heat exchangers 23a and 23b. The refrigerant sent to the outdoor heat exchangers 23a and 23b evaporates by heating through heat exchange with the outdoor air supplied by the outdoor fan 24. The refrigerant joins the refrigerant sent to the outdoor unit 2 through the low-pressure refrigerant gas connection pipe 8 and is sucked into the compressor 21, through the switching mechanisms 22a and 22b.

In the main heating operation described above, as a heating-only operation, the control unit 19 performs the control to set the opening degree of the liquid pressure adjusting expansion valve 26 in a fully open state. Thus, the opening degree of the refrigerant return expansion valve 44 is brought to a fully closed state to prevent refrigerant from flowing into the refrigerant return pipe 41.

Operation with refrigerant leak

The operation of the air conditioner 1 when the refrigerant leaks is described below with reference to Figs. 9 to 11. Fig. 11 is a flowchart of an operation when a refrigerant leak occurs in the air conditioner 1 according to the second embodiment of the present description. The operation of the air conditioner 1 described later is performed by the control unit 19, which controls the components of the air conditioner 1 (the outdoor unit 2, the indoor units 3a, 3b, 3c and 3d and the relay units 4a, 4b, 4c and 4d) as the operation when the refrigerant does not leak.

The air conditioner 1 is provided with the refrigerant sensors 57a, 57b, 57c and 57d, which serve as the refrigerant leak detecting means, as described above. When the refrigerant sensors 57a, 57b, 57c and 57d detect refrigerant leakage, the indoor expansion valves 51a, 51b, 51c and 51d and the cooling/heating switching valves 58a, 58b, 58c, 58d, 59a, 59b , 59c and 59d are closed in accordance with the information from the refrigerant sensors 57a, 57b, 57c and 57d. Thus, the indoor units 3a, 3b, 3c and 3d can be isolated. Accordingly, the refrigerant can be prevented from flowing from the refrigerant connecting pipes 5 and 6 to the indoor units 3a, 3b, 3c and 3d. That is, when the refrigerant leaks, the indoor expansion valves 51a, 51b, 51c, and 51d are also used as the liquid side stop valves, the cooling/heating switching valves 58a, 58b, 58c, 58d, 59a, 59b, 59c and 59d are also used as gas side stop valves, and these valves are closed, thus providing a refrigerant stop function when refrigerant leaks from indoor units 3a, 3b, 3c and 3d .

More specifically, when the refrigerant sensors 57a, 57b, 57c and 57d detect refrigerant leakage (step ST1), the control unit 19 closes the indoor expansion valves 51a, 51b, 51c and 51d and the cooling switching valves. / heating 58a, 58b, 58c, 58d, 59a, 59b, 59c and 59d (step ST4). Additionally, when a refrigerant leak is detected in step ST1, an alarm may be given (step ST2). Furthermore, before the indoor expansion valves 51a, 51b, 51c and 51d and the cooling/heating switching valves 58a, 58b, 58c, 58d, 59a, 59b, 59c and 59d are closed, the compressor 21 can be stopped ( step ST3) to suppress an excessive rise in refrigerant pressure.

In this way, the indoor expansion valves 51a, 51b, 51c and 51d and the cooling/heating switching valves 58a, 58b, 58c, 58d, 59a, 59b, 59c and 59d are closed in accordance with the information of the refrigerant sensors 57a, 57b, 57c and 57d serving as refrigerant leak detecting means when refrigerant leaks. In this way, the refrigerant is prevented from flowing from the refrigerant connecting pipes 5 and 6 to the indoor units 3a, 3b, 3c and 3d, and the increase of the refrigerant concentration in the target spaces of conditioning can be suppressed. of air.

Features

The air conditioner 1 and the indoor units 3a, 3b, 3c and 3d used for the air conditioner 1 according to this embodiment have the following features.

As the air conditioner 1 and the indoor units 3a and 3b used for the air conditioner 1 according to the first embodiment, the air conditioner 1 and the indoor units 3a, 3b, 3c and 3d used for the air conditioner 1 according to this embodiment, they also have a problem of refrigerant leakage from the brazing portions 82a, 82b, 82c, and 82d that braze the indoor expansion valves 51a, 51b, 51c, and 51d and the indoor refrigerant liquid pipes. connection side 72a, 72b, 72c and 72d when the indoor expansion valves 51a, 51b, 51c and 51d are also used as stop valves on the liquid sides of the indoor units 3a, 3b, 3c and 3d.

In this case, as the air conditioner 1 and the indoor units 3a and 3b used for the air conditioner 1 according to the first embodiment, leakage of the refrigerant from the brazing portions 82a, 82b is suppressed, 82c and 82d is reduced by providing coating materials 11a, 11b, 11c and 11d on the brazing portions 82a, 82b, 82c and 82d.

Therefore, as the air conditioner 1 and the indoor units 3a and 3b used for the air conditioner 1 according to the first embodiment, the refrigerant shutdown function for the situation that refrigerant leaks from the indoor units 3a, 3b, 3c and 3d can be added as the cost and sizes of the indoor units 3a, 3b, 3c and 3d increase due to the provision of stop valves on the liquid sides of the indoor units 3a, 3b, 3c, and 3d are reduced as much as possible.

In particular, as described above, the cooling/heating switching valves 58a, 58b, 58c, 58d, 59a, 59b, 59c and 59d of the relay units 4a, 4b, 4c and 4d used to individually switch the states operating conditions of the indoor units 3a, 3b, 3c and 3d (that is, the states in which the indoor heat exchangers 52a, 52b, 52c and 52d function as refrigerant evaporators and function as refrigerant radiators) are They are also used as shut-off valves on the gas side. As long as the cooling/heating switching valves 58a, 58b, 58c, 58d, 59a, 59b, 59c and 59d can also be used as stop valves on the gas sides of the indoor units 3a, 3b, 3c and 3d , to be able to suppress the increase in the cost and sizes of the indoor units 3a, 3b, 3c and 3d by that amount.

Accordingly, the refrigerant shutdown function for the situation that refrigerant leaks from the indoor units 3a, 3b, 3c and 3d can be added while the increase in the cost and sizes of the indoor units 3a , 3b, 3c and 3d due to the provision of stop valves on the gas sides of the indoor units 3a, 3b, 3c, and 3d is reduced as much as possible.

Since the outdoor unit 2 includes the liquid pressure adjusting expansion valve 26 as the air conditioner 1 according to the first embodiment, the two-phase refrigerant feed to decompress the refrigerant to bring it to the gas-liquid two-phase state in the unit 2 and then send the refrigerant to the indoor units 3a, 3b, 3c and 3d through the refrigerant liquid connection pipe 5 is done. Therefore, as the air conditioner 1 according to the first embodiment, even in the case that the two-phase refrigerant supply is not enough to counter the refrigerant leakage, the refrigerant shutdown function for the situation where the refrigerant is leakage of indoor units 3a, 3b, 3c and 3d can be added while the increase in cost and sizes of indoor units 3a, 3b, 3c and 3d due to the provision of stop valves on the sides of liquid in the indoor units 3a, 3b, 3c, and 3d is reduced as much as possible. The addition of the refrigerant shutdown function makes the countermeasure to refrigerant leakage sufficient.

first modification

In this embodiment, only the indoor expansion valves 51a, 51b, 51c and 51d are provided in the indoor refrigerant liquid pipes 53a, 53b, 53c and 53d, as illustrated in Fig. 10 in the indoor units 3a, 3b, 3c and 3d arranged in the air conditioning target spaces. Additionally, filters 73a, 73b, 73c and 73d to reduce the ingress of foreign substances, etc., to the indoor expansion valves 51a, 51b, 51c and 51d can be provided in the indoor refrigerant liquid pipes on the supply side. connection 72a, 72b, 72c and 72d, as illustrated in Fig. 12 in the indoor units 3a, 3b, 3c and 3d. The filters 73a, 73b, 73c and 73d are also connected to the connection side indoor refrigerant liquid pipes 72a, 72b, 72c and 72d by brazing. The connection side indoor refrigerant liquid pipes 72a, 72b, 72c and 72d include the first connection side indoor refrigerant liquid pipes 74a, 74b, 74c and 74d connected to the indoor expansion valves 51a, 51b, 51c and 51 d and the second connection side indoor refrigerant liquid pipes 75a, 75b, 75c and 75d connected to the refrigerant liquid connection pipe 5 (in this case, the branch pipe portions 5aa, 5bb, 5cc and 5dd) . Additionally, the filters 73a, 73b, 73c and 73d are connected between the first connection side indoor refrigerant liquid pipes 74a, 74b, 74c and 74d and the second connection side indoor refrigerant liquid pipes 75a, 75b, 75c and 75d. The filters 73a, 73b, 73c and 73d are connected to the first connection side indoor refrigerant liquid pipes 74a, 74b, 74c and 74d and the second connection side indoor refrigerant liquid pipes 75a, 75b, 75c and 75d by brazing (the brazing portions are referred to as brazing portions 85a, 85b, 85c, 85d, 86a, 86b, 86c, and 86d). Due to this, the brazing portions 85a, 85b, 85c, 85d, 86a, 86b, 86c and 86d may corrode and refrigerant may leak from the corroded portions. This makes it difficult to use the indoor expansion valves 51a, 51b, 51c and 51d as well as the stop valves on the liquid sides of the indoor units 3a, 3b, 3c and 3d, such as the brazing portions 85a, 85b, 86a and 86b of the indoor units 3a and 3b according to the first embodiment.

To address this, as illustrated in Figure 12, braze portions 85a, 85b, 85c, 85d, 86a, 86b, 86c, and 86d by brazing filters 73a, 73b, 73c, and 73d to the first coolant lines of connection side indoor 74a, 74b, 74c and 74d and the second connection side indoor refrigerant liquid pipes 75a, 75b, 75c and 75d are also provided with lining materials 11a, 11b, 11c, 11d, 12a, 12b , 12c and 12d. The first connection side indoor refrigerant liquid pipes 74a, 74b, 74c and 74d including the brazing portions 82a, 82b, 82c and 82d and the brazing portions 85a, 85b, 85c and 85d are provided with the coating materials 11a, 11b, 11c and 11d. The second connecting side indoor refrigerant liquid pipes (75a, 75b, 75c and 75d, including the brazing portions 86a, 86b, 86c and 86d and the brazing portions 83aa, 83bb, 83cc and 83dd brazes are provided with 12a, 12b, 12c and 12d facing materials. When the second connection side indoor refrigerant liquid pipes 75a, 75b, 75c and 75d are directly connected to the refrigerant liquid connection pipe 5 (in this case, the branch pipe portions 5aa, 5bb, 5cc and 5dd) by brazing, the lining materials 12a, 12b, 12c and 12d can be provided to include the brazing portions that braze the second connection side indoor refrigerant liquid pipes 75a, 75b, 75c and 75d and the liquid-refrigerator connection 5 (in this case, the bifurcated pipe portions 5aa, 5bb, 5cc and 5dd). The way of providing the covering materials is not limited to the way described above as the indoor units 3a and 3b according to the first embodiment. Accordingly, leakage of the refrigerant from the brazing portions 85a, 85b, 85c, 85d, 86a, 86b, 86c and 86d is suppressed by brazing the filters 73a, 73b, 73c and 73d with the first refrigerant liquid pipes inside the connection side 74a, 74b, 74c and 74d and the connection side second indoor refrigerant liquid pipes 75a, 75b, 75c and 75d is reduced, so that the indoor expansion valves 51a, 51b, 51c and 51d are also can be used as stop valves on the liquid sides of the indoor units 3a, 3b, 3c and 3d.

Even in the case that the filters 73a, 73b, 73c and 73d are provided in the connection side indoor refrigerant liquid pipes 72a, 72b, 72c and 72d, the refrigerant shutdown function for the situation that the refrigerant leaks from indoor units 3a, 3b, 3c and 3d can be added while the increase in cost and sizes of indoor units 3a, 3b, 3c and 3d due to the provision of stop valves in the liquid sides of the indoor units 3a, 3b, 3c, and 3d is reduced as much as possible.

second modification

In the external stop valve units 4a, 4b, 4c and 4d, the cooling/heating switching valves 58a, 58b, 58c, 58d, 59a, 59b, 59c and 59d that serve as the gas side stop valves are connected to the gas connection pipes 62a, 62b, 62c and 62d connected to the refrigerant gas connection pipe 6 (the indoor side high-pressure gas connection pipes 66a, 66b, 66c and 66d, the connection pipes the outdoor side high-pressure gas pipes 67a, 67b, 67c, and 67d, the indoor-side low-pressure gas connection pipes 68a, 68b, 68c, and 68d, and the outdoor-side low-pressure gas connection pipes 69a , 69b, 69c and 69d) by brazing. Due to this, the brazing portions 92a, 92b, 92c and 92d that braze the first cooling/heating switching valves 58a, 58b, 58c and 58d and the outdoor side high-pressure gas connecting pipes 67a, 67b , 67c and 67d may corrode and coolant may leak from the corroded portions. Additionally, the brazing portions 94a, 94b, 94c, and 94d that braze the second cooling/heating switching valves 59a, 59b, 59c, and 59d and the outdoor side high-pressure gas connecting pipes 69a, 69b , 69c and 69d may corrode and coolant may leak from the corroded portions. In the above-described embodiment and the first modification, however, the relay units 4a, 4b, 4c, and 4d are arranged outside the target air conditioning spaces. Therefore, even when the refrigerant leaks from the brazing portions 92a, 92b, 92c, 92d, 94a, 94b, 94c and 94d, the refrigerant hardly leaks into the air conditioning target spaces. On the contrary, when the relay units 4a, 4b, 4c and 4d are arranged in the air conditioning target spaces together with the indoor units 3a, 3b, 3c and 3d, if the refrigerant leaks from the soldering portions 92a, 92b, 92c, 92d, 94a, 94b, 94c and 94d, refrigerant is continuously supplied from the refrigerant gas connecting pipe 6 to the brazing portions 92a, 92b, 92c, 92d, 94a, 94b, 94c and 94d, and the refrigerant can continuously leak from the external stop valve units 4a, 4b, 4c and 4d to the target air conditioning spaces, although the cooling/heating switching valves 58a, 58b, 58c, 58d, 59a, 59b, 59c and 59d are closed. Thus, it is required to reduce refrigerant leakage from the brazing portions 92a, 92b, 92c, 92d, 94a, 94b, 94c and 94d.

To address this, as illustrated in Fig. 13, the brazing portions 92a, 92b, 92c, and 92d that braze the first cooling/heating switching valves 58a, 58b, 58c, and 58d and the gas connection pipes of outer side high pressure 67a, 67b, 67c and 67d are also provided with coating materials 13a, 13b, 13c and 13d. Additionally, the brazing portions 94a, 94b, 94c, and 94d that braze the second cooling/heating switching valves 59a, 59b, 59c, and 59d and the outdoor side low-pressure gas connection pipes 69a, 69b , 69c and 69d are also provided with coating materials 14a, 14b, 14c and 14d. The coating materials 13a, 13b, 13c, 13d, 14a, 14b, 14c, and 14d may also be provided only in the brazed portions 92a, 92b, 92c, 92d, 94a, 94b, 94c, and 94d, or may also be providing in a portion other than brazing portions 92a, 92b, 92c, 92d, 94a, 94b, 94c, and 94d. For example, as illustrated in Fig. 13, the lining materials 13a, 13b, 13c and 13d can be provided at an interval from the first cooling/heating switching valves 58a, 58b, 58c and 58d to the joint portions. of the pipe 96a, 96b, 96c and 96d of the outdoor side high-pressure gas connection pipes 67a, 67b, 67c and 67d (that is, to include the brazing portions 92a, 92b, 92c and 92d and the brazing portions 92a, 92b, 92c and 92d braze 96aa, 96bb, 96cc and 96dd). When the outdoor side high-pressure gas connection pipes 67a, 67b, 67c and 67d are directly connected to the refrigerant gas connection pipe 6 (in this case, the first branch pipe portions 7a, 7d, 7c and 7d of the high/low pressure refrigerant gas connecting pipe 7) by brazing, the lining materials 13a, 13b, 13c and 13d can be provided at an interval from the first cooling/heating switching valves 58a, 58b, 58c and 58d to the brazing portions that weld the outdoor side gas connection pipes 67a, 67b, 67c, and 67d and the refrigerant gas connection pipe 6 (in this case, the first branch pipe portions 7a, 7b, 7c and 7d of the pipe high/low pressure refrigerant gas connection 7). The lining materials 14a, 14b, 14c, and 14d may be provided at a range from the second cooling/heating switching valves 59a, 59b, 59c, and 59d to the pipe joint portions 97a, 97b, 97c, and 97d of the outdoor side low-pressure gas connecting pipes 69a, 69b, 69c and 69d (that is, to include the brazing portions 94a, 94b, 94c and 94d and the brazing portions 97aa, 97bb, 97cc and 97dd ). When the outdoor side low-pressure gas connection pipes 69a, 69b, 69c and 69d are directly connected to the refrigerant gas connection pipe 6 (in this case, the branch pipe portions 8a, 8b, 8c and 8d of the low-pressure refrigerant gas connecting pipe 8 by brazing, the lining materials 14a, 14b, 14c and 14d can be provided in an interval from the second cooling/heating switching valves 59a, 59b, 59c and 59d to the brazing portions brazing the outdoor side low-pressure gas connection pipes 69a, 69b, 69c, and 69d and the refrigerant gas connection pipe 6 (in this case, the branch pipe portions 8a, 8b, 8c and 8d of the low-pressure refrigerant gas connecting pipe 8).Therefore, leakage of the refrigerant from the brazing portions 92a, 92b, 92c and 92d which braze the first cooling/heating switching valves is suppressed. 58a, 58b, 58c and 58d and the outdoor side high-pressure gas connection pipes 67a, 67b, 67c and 67d are reduced, leakage of the refrigerant from the brazing portions 94a, 94b, 94c and 94d is suppressed which solder the second cooling/heating switching valves 59a, 59b, 59c and 59d and the outdoor side low-pressure gas connecting pipes 69a, 69b, 69c and 69d is reduced and thus the relay units 4a, 4b, 4c and 4d are not arranged in the air conditioning target spaces, but indoor units 3a, 3b, 3c and 3d. Referring to Fig. 13, in the configuration of the embodiment described above (see Fig. 10) without the filters 73a, 73b, 73c and 73d, the brazing portions 92a, 92b, 92c and 92d that braze the first valves cooling/heating switching pipes 58a, 58b, 58c and 58d and the outdoor side high-pressure gas connection pipes 67a, 67b, 67c and 67d, as well as the brazing portions 94a, 94b, 94c and 94d that weld the second cooling/heating switching valves 59a, 59b, 59c and 59d and the outdoor side low-pressure gas connecting pipes 69a, 69b, 69c and 69d are provided with the lining materials 13a, 13b, 13c, 13d, 14a, 14b, 14c and 14d; however, it is not limited to the above. For example, in the first modification configuration described above (see Figure 12) with filters 73a, 73b, 73c, and 73d, the brazing portions 92a, 92b, 92c, and 92d brazing the first cooling switching valves /heating pipes 58a, 58b, 58c and 58d and the outdoor side high-pressure gas connection pipes 67a, 67b, 67c and 67d, as well as the brazing portions 94a, 94b, 94c and 94d that braze the second valves cooling/heating switching 59a, 59b, 59c and 59d and the outdoor side low-pressure gas connecting pipes 69a, 69b, 69c and 69d may be provided with the lining materials 13a, 13b, 13c, 13d, 14a, 14b, 14c and 14d.

Accordingly, the degree of freedom is ensured for the arrangement of the relay units 4a, 4b, 4c and 4d.

Third modification

In the above-described embodiment and the first and second modifications, as illustrated in Fig. 11, when the refrigerant sensors 57a, 57b, 57c, and 57d detect refrigerant leakage, all the internal expansion valves 51a, 51b, 51c, and 51d and the cooling/heating switching valves 58a, 58b, 58c, 58d, 59a, 59b, 59c and 59d are closed and the compressor 21 is stopped in accordance with the information from the refrigerant sensors 57a, 57b, 57c and 57d . Accordingly, the circulation of the refrigerant in the refrigerant circuit 10 is stopped, and the cooling operation or the heating operation is stopped not only in the indoor unit in which the refrigerant is leaked, but also in the indoor unit in which the refrigerant does not leak.

However, it is desirable that only the indoor unit in which refrigerant leakage occurs is isolated, while the indoor unit in which refrigerant leakage does not occur can continue cooling operation or cooling operation. heating.

As illustrated in Fig. 14, when the refrigerant sensors 57a, 57b, 57c and 57d detect refrigerant leakage (step ST1), the control unit 19 closes only the indoor expansion valve and the cooling/cooling switching valve. heating corresponding to the indoor unit in which the refrigerant leaks between the plurality of indoor units 3a, 3b, 3c and 3d (step ST5). Then, by continuing the circulation of the refrigerant in the refrigerant circuit 10 without stopping the compressor 21, the cooling operation or the heating operation of the indoor unit in which there is no refrigerant leakage is continued (step ST6).

When refrigerant leaks from the indoor units 3a, 3b, 3c and 3d, only the indoor unit in which refrigerant leakage occurs is isolated, while the indoor unit in which refrigerant leakage does not occur is isolated. refrigerant can continue operation.

fourth modification

In the above-described embodiment and the first to third modifications, relay units 4a, 4b, 4c, and 4d corresponding respectively to indoor units 3a, 3b, 3c, and 3d are provided; however, it is not limited to it. For example, a relay unit may collectively consist of all of the relay units 4a, 4b, 4c, and 4d, or some of the relay units 4a, 4b, 4c, and 4d.

industry application

The present description can be widely applied to an air conditioner configured in such a way that an outdoor unit and an indoor unit arranged in an air conditioning target space are connected with each other through a refrigerant liquid connection pipe and a refrigerant gas connecting pipe and to an indoor unit used for the air conditioner.

List of reference signs

1 air conditioner

2 outdoor unit

3a, 3b, 3c, 3d indoor unit

4a, 4b, 4c, external stop valve unit 4d, relay unit

5 coolant connection pipe

6 refrigerant gas connection pipe

11a, 11b, 11c, 11d lining material

12a, 12b, 12c, 12d lining material

13a, 13b, 13c, 13d lining material

14a, 14b, 14c, 14d lining material

15a, 15b coating material

19 control unit

23, 23a, 23b outdoor heat exchanger

26 liquid pressure adjustment expansion valve

51a, 51b, 51c, 51d indoor expansion valve

52a, 52b, 52c, 52d indoor heat exchangers

57a, 57b, 57c, 57d refrigerant sensor (refrigerant leak detection means)

58a, 58b, 58c, 58d gas side shutoff valve, first cooling/heating switching valve 59a, 59b, 59c, 59d second cooling/heating switching valve (gas side shutoff valve)

66a, 66b, 66c, 66d inner side gas connection pipe

67a, 67b, 67c, 67d outdoor side gas connection pipe

68a, 68b, 68c, 68d inner side gas connection pipe

69a, 69b, 69c, 69d outdoor side gas connection pipe

71a, 71b, 71c, 71d heat exchange side indoor refrigerant liquid pipe

72a, 72b, 72c, 72d connection side indoor refrigerant liquid pipe

73a, 73b, 73c, 73d filter

74a, 74b, 74c, 74d first connection side indoor refrigerant liquid pipe

75a, 75b, 75c, 75d second connection side indoor refrigerant liquid pipe

76a, 76b indoor refrigerant gas pipe of heat exchange side

77a, 77b connection side indoor refrigerant gas pipe

82a, 82b, 82c, 82d brazing portion

85a, 85b, 85c, 85d brazing portion

86a, 86b, 86c, 86d brazing portion

88a, 88b brazing portion

92a, 92b, 92c, 92d brazing portion

94a, 94b, 94c, 94d brazing portion

appointment list

PATENT BIBLIOGRAPHY PTL1

International Publication No. 2015/029160

Claims (13)

1. An air conditioner (1) comprising: an outdoor unit (2); a refrigerant liquid connection pipe (5) and a refrigerant gas connection pipe (6); an indoor unit (3a, 3b, 3c, 3d) connected to the outdoor unit (2) through the refrigerant liquid connection pipe (5) and the refrigerant gas connection pipe (6), arranged in a air conditioning target space and including an indoor heat exchanger (52a, 52b, 52c, 52d) which performs heat exchange between a refrigerant, circulating between the indoor unit and the outdoor unit (2) at through the refrigerant liquid connection pipe (5) and the refrigerant gas connection pipe (6), and an air, which is sent to the air conditioning target space, an indoor expansion valve (51a, 51b, 51c, 51d) decompressing the refrigerant, a heat exchange side indoor refrigerant liquid pipe (71a, 71b, 71c, 71d) connecting a liquid side of the indoor heat exchanger to the indoor expansion valve and a coolant line inside the side o connection (72a, 72b, 72c, 72d) connecting the indoor expansion valve to the refrigerant liquid connection pipe (5); a gas side stop valve (58a, 58b, 58c, 58d, 59a, 59b, 59c, 59d) which is connected to a gas side of the indoor heat exchanger; refrigerant leak detecting means (57a, 57b, 57c, 57d) for detecting a leak of the refrigerant; and a control unit (19), characterized in that the indoor expansion valve is connected to the connection side indoor refrigerant liquid pipe by brazing, brazing portions (82a, 82b, 82c, 82d) brazing the indoor expansion valve and the connection side indoor refrigerant liquid pipe, each provided with a coating material (11a, 11b, 11c, 11 d), and The control unit (19) causes the indoor expansion valve and the gas side stop valve to close in accordance with information from the refrigerant leak detecting means when there is a refrigerant leak. The air conditioner (1) according to claim 1, wherein the connection side indoor refrigerant liquid pipe includes a first connection side indoor refrigerant liquid pipe (74a, 74b, 74c, 74d) connected to the indoor expansion valve, a second indoor refrigerant liquid pipe connection side (75a, 75b, 75c, 75d) connected to the refrigerant liquid connection pipe (5), and a filter (73a, 73b, 73c, 73d) which is connected between the first indoor refrigerant liquid pipe connection side and the second indoor refrigerant pipe on the connection side, the filter is connected to the first connection-side indoor refrigerant pipe and the second connection-side indoor refrigerant pipe by brazing, and brazing portions (85a, 85b, 85c, 85d, 86a, 86b, 86c, 86d) brazing the filter with the connection-side first indoor refrigerant liquid pipe and the connection-side second indoor refrigerant liquid pipe connection, each being provided with a coating material (11a, 11b, 11c, 11d, 12a, 12b, 12c, 12d). The air conditioner (1) according to claim 1 or 2, wherein the outdoor unit (2) includes an outdoor heat exchanger (23, 23a, 23b) and a liquid pressure adjustment expansion valve (26), and When the refrigerant is sent from the outdoor heat exchanger to the indoor unit through the refrigerant liquid connection pipe (5), the control unit (19) controls the liquid pressure adjusting expansion valve to decompress the refrigerant flowing through the refrigerant liquid connection pipe (5) to bring it into a gas-liquid two-phase state, and control the indoor expansion valve to decompress the refrigerant decompressed by the pressure adjustment expansion valve of liquid. The air conditioner (1) according to any one of claims 1 to 3, wherein the indoor unit includes a plurality of the indoor units, and the gas side stop valve is provided to match each of the indoor units. The air conditioner (1) according to claim 4, wherein the control unit (19) causes only the indoor expansion valve and the gas side stop valve corresponding to the indoor unit in which the refrigerant is leaked among the plurality of indoor units to be closed in accordance with the information from the refrigerant leak detecting means when the refrigerant leaks. The air conditioner (1) according to any one of claims 1 to 5, wherein the refrigerant gas connecting pipe (6) is provided with an external stop valve unit (4a, 4b) including the gas side stop valve. The air conditioner (1) according to claim 6, wherein the gas side stop valve is connected, by brazing, to a gas connection pipe of the indoor unit (66a, 66b) which is connected to a portion of the refrigerant gas connection pipe (6) on one side of the indoor unit, and an outdoor side gas connection pipe (67a, 67b ) which is connected to a portion of the refrigerant gas connection pipe (6) on one side of the outdoor unit (2), and A brazing portion (92a, 92b) that welds the gas-side stop valve and the outdoor-side gas connection pipe is also provided with a lining material (13a, 13b). The air conditioner (1) according to claim 4 or 5, wherein the refrigerant gas connection pipe (6) is provided with a relay unit (4a, 4b, 4c, 4d) including a cooling/heating switching valve (58a, 58b, 58c, 58d, 59a, 59b, 59c , 59d) individually switching a corresponding one of the plurality of indoor heat exchangers to function as an evaporator or a radiator of the refrigerant, and the control unit (19) causes the indoor expansion valve and the cooling/heating switching valve serving as the gas side stop valve to be closed in accordance with information from the refrigerant leak detecting means when the refrigerant leaks. The air conditioner (1) according to claim 8, wherein The cooling/heating switching valve is connected, by brazing, to an indoor side gas connection pipe (66a, 66b, 66c, 66d, 68a, 68b, 68c, 68d) which is connected to a portion of the refrigerant gas connection pipe (6) on one side of the indoor unit, and an outdoor side gas connection pipe (67a, 67b, 67c, 67d, 69a, 69b, 69c, 69d) which is connected to a portion of the refrigerant gas connection pipe (6) on one side of the outdoor unit (2), and a brazing portion (92a, 92b, 92c, 92d, 94a, 94b, 94c, 94d) brazing the cooling/heating switching valve and the outdoor side gas connection pipe is also provided with a brazing material lining (13a, 13b, 13c, 13d, 14a, 14b, 14c, 14d). The air conditioner (1) according to any one of claims 1 to 5, wherein gas side stop valve is provided in the indoor unit, the indoor unit includes a heat exchange side indoor refrigerant gas pipe (76a, 76b) connecting the gas side of the indoor heat exchanger to the gas side stop valve and a refrigerant gas pipe connection side indoor pipe (77a, 77b) connecting the gas side stop valve with the refrigerant gas connection pipe (6), the gas side stop valve is connected to the connection side indoor refrigerant gas pipe by brazing, and A brazing portion (88a, 88b) that welds the gas-side stop valve and the connection-side indoor refrigerant gas pipe is also provided with a lining material (15a, 15b). The air conditioner (1) according to any one of the preceding claims, wherein the coating material is urethane resin. 12. An indoor unit (3a, 3b, 3c, 3d) connected to an outdoor unit (2) through a refrigerant liquid connection pipe (5) and a refrigerant gas connection pipe (6) and arranged in an air conditioning target space, the indoor unit comprising: an indoor heat exchanger (52a, 52b, 52c, 52d) that performs heat exchange between a refrigerant, which circulates between the indoor unit and the outdoor unit (2) through the refrigerant liquid connection pipe (5) and the refrigerant gas connection pipe (6), and an air, which is sent to the air conditioning target space; an internal expansion valve (51a, 51b, 51c, 51d) that decompresses the refrigerant; a heat exchange side indoor refrigerant liquid pipe (71a, 71b, 71c, 71d) connecting a liquid side of the indoor heat exchanger to the indoor expansion valve; Y a connection side indoor refrigerant liquid pipe (72a, 72b, 72c, 72d) connecting the indoor expansion valve to the refrigerant liquid connection pipe (5), characterized in that the indoor expansion valve is connected to the connection side indoor refrigerant liquid pipe by brazing, and a brazing portion (82a, 82b, 82c, 82d) that welds the indoor expansion valve and the connection side indoor refrigerant liquid pipe is provided with a lining material (11a, 11b, 11c, 11d) . The indoor unit according to claim 12, further comprising: a gas side stop valve (58a, 58b, 58c, 58d) which is connected to a gas side of the indoor heat exchanger; a heat exchange side indoor refrigerant gas pipe (76a, 76b) connecting the gas side of the indoor heat exchanger to the gas side stop valve; Y a connection side indoor refrigerant gas pipe (77a, 77b) connecting the gas side stop valve with the refrigerant gas connection pipe (6), wherein the gas side stop valve is connected to the connection side indoor refrigerant gas pipe by brazing, and A brazing portion (88a, 88b) that welds the gas-side stop valve and the connection-side indoor refrigerant gas pipe is also provided with a lining material (15a, 15b).