WO2008059922A1 - Multi-type air conditioner - Google Patents

Abstract

In recent years, there is known a multi-type air conditioner, which establishes a freezing cycle by connecting a plurality of outdoor equipments as the load of a cooling/warming operation increases. In case an outdoor equipment to be operated and an outdoor equipment to be stopped coexist, a high-pressure liquid coolant, as discharged from the operated outdoor equipment, flows via a liquid connecting pipe into the stopped outdoor equipment. As a result, the quantity of a circulating coolant in the freezing cycle may be reduced to lower the reliability of a compressor due to an ability shortage or a discharge temperature rise of the compressor. Intended is to suppress the reduction of the circulating coolant quantity in the multi-type air conditioner. In the multi-type air conditioner, a plurality of outdoor equipments (10) and a plurality of indoor equipments (40) are connected in parallel with a liquid connecting pipe (35) and a gas connecting pipe (36), respectively, thereby to establish the freezing cycle. The outdoor equipment (10) includes a compressor (11) connected with a gas coolant pipe through a valve, an outdoor heat exchanger (14) connected with that compressor, a receiver (25) connected with that outdoor heat exchanger, and an automatic switch valve (23) interposed between that receiver and a liquid coolant pipe. The outdoor equipment is controlled such that the automatic switch valve (23) is closed when the operation is stopped. Even if the outdoor equipment to be operated and the outdoor equipment to be stopped coexist, therefore, the coolant is not accumulated in the receiver of the outdoor equipment to be stopped, so that the reduction in the circulating coolant quantity can be suppressed.

Description

 Specification

 Multi-type air conditioner

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a multi-type air conditioner having a plurality of outdoor units, and more particularly to operation control of an outdoor unit.

 Background art

 [0002] In recent years, multi-type air conditioners are known in which a plurality of outdoor units are connected to form a refrigeration cycle as the load of air conditioning operation increases.

 [0003] As such a multi-type air conditioner, for example, a plurality of outdoor units and a plurality of indoor units are connected in parallel to a liquid connection pipe and a gas connection pipe, respectively, and between the outdoor unit and the indoor unit. An air conditioner is known in which a refrigerant is circulated in the air (see Patent Document 1). here

In each outdoor unit, for example, a four-way valve, a compressor, an outdoor heat exchanger, an outdoor expansion valve, and a receiver are sequentially connected by piping, and the gas connection piping is compressed via the four-way valve. The liquid connection piping is connected to the receiver by piping. Further, for example, an indoor expansion valve and an indoor heat exchanger are accommodated in the housing of each indoor unit.

 [0004] According to the multi-type air conditioner configured as described above, for example, depending on the environment of the room in which each indoor unit is installed, the indoor unit is operated with a difference in capacity or air volume. That's the power S. In addition, since a plurality of outdoor units are connected to each indoor unit, the number of outdoor units that can be operated can be increased as needed in response to an increase in the load on the indoor side.

Patent Document 1: Japanese Patent Laid-Open No. 11 14168

 Disclosure of the invention

 Problems to be solved by the invention

[0006] By the way, in such a multi-type air conditioner, the load on the indoor side is small, and when all the outdoor units are operated simultaneously, the efficiency deteriorates. The machine is stopped.

[0007] However, when the outdoor unit that operates and the outdoor unit that stops are mixed, for example, For example, the high-pressure liquid refrigerant discharged from the outdoor unit that performs the cooling operation may flow into the outdoor unit that stops through the liquid connection pipe and accumulate in the receiver. Since this receiver occupies a large volume in the refrigerant circulation path of the refrigeration cycle, if liquid refrigerant accumulates in the receiver of the outdoor unit that stops, the amount of refrigerant circulation in the refrigeration cycle decreases, resulting in insufficient capacity and compressor capacity. There is a risk of reducing the reliability of the compressor due to an increase in the discharge temperature.

[0008] An object of the present invention is to suppress a decrease in refrigerant circulation rate in a multi-type air conditioner to which a plurality of outdoor units are connected.

 Means for solving the problem

[0009] In order to solve the above problems, the present invention provides a plurality of outdoor units and a plurality of indoor units connected in parallel to a liquid connection pipe and a gas connection pipe, respectively. In a multi-type air conditioner that circulates refrigerant between the outdoor unit, the outdoor unit is connected to the compressor connected to the gas connection pipe and the valve, the outdoor heat exchanger connected to the compressor, and the outdoor heat exchanger. And an automatic open / close valve provided between the receiver and the liquid connection pipe, and the outdoor unit is controlled so that the automatic open / close valve is closed when operation is stopped. It is a feature.

 [0010] According to this, even when the outdoor unit to be operated and the outdoor unit to be stopped are mixed, the automatic open / close valve is closed for the outdoor unit to be stopped, so that the liquid refrigerant can be prevented from flowing into the receiver. For this reason, the fall of the refrigerant | coolant circulation amount of the refrigerating cycle which liquid refrigerant does not accumulate in a receiver can be suppressed. In addition, the refrigerant flowing into the outdoor unit is not limited to liquid refrigerant, but gas refrigerant is also conceivable, but since various valves and compressors are provided between the receiver and the gas connection pipe, the gas refrigerant is supplied to the receiver. There is no flow.

[0011] Further, the present invention provides a plurality of outdoor units and a plurality of indoor units connected in parallel to a liquid connection pipe, a low pressure gas connection pipe, and a high pressure gas connection pipe, respectively. In the multi-type air conditioner, in which a refrigerant is circulated between the pipes and the open / close valves are provided in the pipe paths connecting the low-pressure gas connection pipe and the high-pressure gas connection pipe to each indoor unit, the outdoor unit is connected to the high-pressure gas Compressor connected to piping and low-pressure gas connection piping via a valve, outdoor heat exchanger connected to the compressor, receiver connected to the outdoor heat exchanger, and between the receiver and liquid connection piping The outdoor unit is equipped with an automatic on-off valve. The automatic open / close valve is controlled to be closed when

[0012] By connecting the indoor unit and the outdoor unit with the three connection pipes as described above, for example, the cooling operation and the heating operation can be simultaneously performed with different indoor units. Also in this configuration, liquid refrigerant can be prevented from accumulating in the receiver of the outdoor unit to be stopped, and a decrease in the refrigerant circulation rate of the refrigeration cycle can be suppressed.

[0013] In the above configuration, the outdoor unit connects the inlet side and the outlet side of the receiver with a first check valve in the forward direction and a second check valve in the forward direction from the outlet side to the inlet side. And a path in which the third check valve in the forward direction and the fourth check valve in the forward direction are connected in series from the outlet side are connected in parallel to form a bridge shape. The connection point between the first check valve and the second check valve is in communication with the outdoor heat exchanger, and the connection point between the third check valve and the fourth check valve is the liquid connection pipe. The fourth check valve may be configured to include an automatic open / close valve.

 [0014] According to this, since the flow direction of the refrigerant flowing into the receiver can be defined in one direction regardless of the cooling or heating operation, the operation efficiency of the refrigeration cycle can be established, for example, a supercooling circuit can be installed in the outlet side piping of the receiver. Various measures can be taken to improve. Even if liquid refrigerant enters the outdoor unit to be stopped, the flow of the refrigerant is stopped by the third check valve and the automatic open / close valve, so that the liquid refrigerant does not enter the receiver.

 [0015] Here, the outdoor unit is controlled so as to close the automatic open / close valve during the cooling operation. As a result, during cooling operation, the refrigerant discharged from the compressor flows into the inlet side of the receiver through the second check valve in the bridge circuit, and the refrigerant discharged from the receiver outlet side passes through the third reverse valve. Since it flows into the liquid connection pipe through the stop valve, the bridge circuit functions as a check valve.

 The invention's effect

 [0016] According to the present invention, in a multi-type air conditioner to which a plurality of outdoor units are connected, it is possible to suppress a decrease in the refrigerant circulation amount, so that the operation capability is ensured and the compressor Highly reliable operation is possible.

 BEST MODE FOR CARRYING OUT THE INVENTION

[0017] Hereinafter, a diagram of an embodiment of a multi-type air conditioner to which the present invention is applied will be described. The description will be given with reference.

 FIG. 1 is a system diagram showing an embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention. This multi-type air conditioner is configured by connecting two outdoor units 10a and 10b and four indoor units 40a, 4 Ob, 40c, and 40d in parallel to the liquid connection pipe 35 and the gas connection pipe 36, respectively. Is done.

 [0019] The number of outdoor units 10 may be more than two, the number of indoor units 40 may be more or less, and the number of indoor units 40 to be operated may be one or more. However, it targets at least one outdoor unit 10 (hereinafter abbreviated as a driving outdoor unit) that operates and stops in that state (hereinafter abbreviated as a stationary outdoor unit).

 In the casing of the outdoor unit 10, as shown in the figure, a compressor 11 that compresses and discharges the refrigerant, and a check valve 12 that flows the refrigerant discharged from the compressor 11 in the discharge direction, A four-way valve 13 that switches the refrigerant circulation direction, an outdoor heat exchanger 14 that exchanges heat between the refrigerant and the outside air, an outdoor expansion valve 15 that functions as a throttle mechanism, and a receiver that stores liquid refrigerant 25 and an automatic opening / closing valve 23 are connected and stored by refrigerant piping. A liquid blocking valve 31 is arranged on the branch pipe branched from the liquid connecting pipe 35. The liquid blocking pipe connected to the automatic opening / closing valve 23 of the outdoor unit 10 is connected to the liquid blocking valve 31. ing. That is, the automatic opening / closing valve 23 and the liquid connection pipe 35 are communicated with each other through this liquid connection pipe. On the other hand, a gas blocking valve (high-pressure gas blocking valve) 32 is provided in the branch pipe branched from the gas connection pipe 36, and the gas blocking valve 32 includes the four-way valve 13 of the outdoor unit 10. Connected gas connection pipe is connected. The liquid blocking valve 31 and the gas blocking valve 32 are opened when the outdoor unit 10 is connected to the liquid connection pipe and the gas connection pipe, and are kept open during the subsequent operation, for example.

[0021] In the casing of the indoor unit 40, an indoor heat exchanger 41 that exchanges heat between the refrigerant and room air and an indoor expansion valve 42 are connected and stored through a refrigerant pipe. The branch pipe branched from the liquid connection pipe 35 is connected to the indoor expansion valve 42 of the indoor unit 40. The branch pipe branched from the gas connection pipe 36 is connected to the indoor heat exchanger 41 of the indoor unit 40. The outdoor unit 10 and the indoor unit 40 are provided with devices such as an outdoor fan (not shown) and various sensors. [0022] In the multi-type air conditioner configured as above, the automatic open / close valve 23 of the cab outdoor unit 10 is opened, the automatic open / close valve 23 of the stop outdoor unit 10 is closed, and the receiver 25 of the stop outdoor unit 10 is closed. The liquid refrigerant is not stored. For this reason, in order to detect the shutdown status of all outdoor units 10, for example, the shutdown of the compressor 11 is detected, and the automatic open / close valve 23 of the shutdown outdoor unit where the compressor 11 stops is set. Control means for closing is provided.

 Next, the refrigerant flow when the outdoor unit 10a is in the cooling operation, the outdoor unit 10b is stopped, the indoor unit 40a is in the cooling operation, and the indoor units 40b, 40c, and 40d are stopped will be described. In the cab outdoor unit 10a, the compressor 11a is set to operate, the outdoor expansion valve 15a, the automatic open / close valve 23a are opened, and the four-way valve 13a is set to the cooling operation side. Here, the cooling operation side indicates a direction in which the compressor discharge side is connected to the outdoor heat exchanger 14a and the gas blocking valve 32a is connected to the compressor suction side. The heating operation side indicates a direction in which the discharge side of the compressor is connected to the gas blocking valve 32a and the outdoor heat exchanger 14a is connected to the suction side of the compressor.

 [0024] The high-pressure gas refrigerant compressed by the compressor 11a passes through the compressor discharge-side check valve 12a, is sent to the outdoor heat exchanger 14a by the four-way valve 13a, and exchanges heat with the outside air to become high-pressure liquid refrigerant. Then, it passes through the outdoor expansion valve 15a and the receiver 25a and is sent to the automatic opening / closing valve 23a. Here, since the automatic opening / closing valve 23a is opened, the liquid refrigerant passes through the liquid blocking valve 31a and is sent to the liquid connection pipe 35.

 [0025] On the other hand, in the stopped outdoor unit 10b, the compressor l ib is stopped, the outdoor expansion valve 15b, the automatic open / close valve 23b are closed, and the four-way valve 13b is set to the cooling operation side. Therefore, the liquid refrigerant flowing through the liquid connection pipe 35 flows into the outdoor unit 10b through the liquid blocking valve 31b. However, since the flow is stopped by the automatic opening / closing valve 23b, the liquid refrigerant does not accumulate in the receiver 25b.

[0026] The liquid refrigerant flowing through the liquid connection pipe 35 is sent to the operating indoor unit 40a, depressurized by the indoor expansion valve 42a, exchanges heat with indoor air in the indoor heat exchanger 41a, and evaporates to become a low-pressure gas refrigerant. . Then, it passes through the gas connection pipe 36 and is sent to the cab outdoor unit 10a. If there is liquid refrigerant in the compressor 1 lb of the stop outdoor unit 10b, the pressure of the gas connection pipe 36 is lower than the pressure inside the compressor. It is recovered as a refrigerant into the gas connection pipe 36. The low-pressure gas refrigerant passes through the gas blocking valve 32a and the four-way valve 13a, is sent to the compressor 11a, and is compressed and circulated again. Note that the refrigerant in the outdoor heat exchanger 14b is compressed Since it is sealed by the machine discharge side check valve 12b and the outdoor expansion valve 15b, it does not easily flow out as a circulating refrigerant. Similarly, the refrigerant inside the receiver 25b is sealed by the outdoor expansion valve 15b and the automatic opening / closing valve 23b and does not flow out.

Next, the refrigerant flow when the outdoor unit 10a is in the heating operation, the outdoor unit 10b is stopped, the indoor unit 40a is in the heating operation, and the indoor units 40b, 40c, and 40d are stopped will be described. In the cab outdoor unit 10a, the compressor 11a is operated, the outdoor expansion valve 15a, the automatic open / close valve 23a is opened, and the four-way valve 13a is set on the heating operation side. The high-pressure gas refrigerant compressed by the compressor 11a passes through the compressor discharge side check valve 12a and is sent to the gas blocking valve 32a and the gas connection pipe 36 by the four-way valve 13a. Then, the gas refrigerant is mainly sent to the indoor unit 40a, where it exchanges heat with the indoor air in the indoor heat exchanger 41a, and the refrigerant condenses to become a high-pressure liquid refrigerant and passes through the fully opened indoor expansion valve 42a. Sent to liquid connection pipe 3 5 Here, the power to stop and stop the indoor units 40b, 40c, 40di When the indoor 11 tension valves 42b, 42c, 42d are fully closed, the refrigerant accumulates in the indoor units 40b, 40c, 40d, so the indoor expansion valve A force to open or slightly open 42 S is preferable. In this case, the refrigerant is slightly condensed in the indoor heat exchangers 41b, 41c, 41d to become high-pressure liquid, and is sent to the liquid connection pipe 35 through the indoor expansion valves 42b, 42c, 42d. The liquid refrigerant sent to the liquid connection pipe 35 is sent to the outdoor units 10a and 10b.

 [0028] The liquid refrigerant sent from the liquid connection pipe 35 is sent to the receiver 25a and the outdoor expansion valve 15a through the liquid blocking valve 3la and the open automatic opening / closing valve 23a in the cab outdoor unit 10a. Then, the pressure is reduced by the outdoor expansion valve 15a and sent to the outdoor heat exchanger 14a to exchange heat with the outside air to become a low-pressure gas refrigerant. The low-pressure gas refrigerant passes through the four-way valve 13a and is sent to the compressor 11a where it is compressed again and circulated.

[0029] On the other hand, in the stopped outdoor unit 10b, the compressor l ib is stopped, the outdoor expansion valve 15b, the automatic open / close valve 23b are closed, and the four-way valve 13b is set to the heating operation state. The high-pressure gas in the gas connection pipe 36 is sent to the gas stop valve 32b. Since it is stopped by the compressor discharge side check valve 12b, it does not accumulate in the outdoor heat exchanger 14b. The liquid refrigerant in the liquid connection pipe 35 enters the stop outdoor unit 10b through the liquid blocking valve 31b, but does not accumulate in the resin 25b because it is stopped by the automatic open / close valve 23b. Note that the refrigerant inside the outdoor heat exchanger 14b is sealed by the compressor discharge side check valve 12b and the outdoor expansion valve 15b, and hardly flows out as a circulating refrigerant. Similarly, the refrigerant inside the receiver 25b is sealed by the outdoor expansion valve 15b and the automatic opening / closing valve 23b and does not flow out.

 [0030] Further, the flow of the refrigerant when the outdoor unit 10a is defrosting, the outdoor unit 10b is stopped, and all the indoor unit expansion valves are open will be described. The cab outdoor unit 10a is the same as the cooling operation, and the liquid refrigerant is sent to the liquid connection pipe 35. On the other hand, in the stopped outdoor unit 10b, the compressor l ib is stopped, the outdoor expansion valve 15b, the automatic open / close valve 23b are closed, and the four-way valve 13b is set to the heating operation state. For this reason, the liquid refrigerant in the liquid connection pipe 35 enters the stop outdoor unit 10b through the liquid blocking valve 31b, but does not accumulate in the receiver 25b because it is stopped by the automatic opening / closing valve 23b. Also, if there is liquid refrigerant in the outdoor heat exchanger 14b, due to the pressure difference, the liquid refrigerant will be four-way valve 1 3b, compressor l lb, compressor discharge side check valve 12b, gas blocking valve 32b, gas connection piping It is sent to outdoor unit 10a through 36. However, the refrigerant flow does not flow in large quantities due to the limitation of the defrosting time that is narrow due to the compressor l ib. Further, the refrigerant does not collect in the outdoor heat exchanger 14b.

 FIG. 2 is a system diagram showing another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention. In this example, in order to regulate the refrigerant flow direction of the receiver in one direction regardless of cooling operation or heating operation in the outdoor unit, a bridge circuit is formed by combining four check valves. One of the check valves in the bridge circuit is the automatic on-off valve 23a shown in Fig. 1. As in FIG. 1, the stop outdoor unit closes the automatic open / close valve 23 between the receiver 25 and the liquid blocking valve 31 to prevent liquid refrigerant from accumulating in the stop outdoor unit. Further, by closing the automatic open / close valve 23 of the cab outdoor unit during cooling operation or defrosting operation, the bridge circuit as a whole can have the same function as the check valve.

[0032] In the outdoor unit 10, the receiver 25 defines one opening as an inlet side (upper part in the figure) and the other opening as an outlet side. As shown in Fig. 2, the bridge circuit connects the inlet side and outlet side of the receiver 25 in series with the first check valve 22 in the forward direction and the second check valve 21 in the forward direction from the outlet side. The connected path and the path in which the third check valve 24 and the automatic opening / closing valve 23 connected in series from the outlet side are connected in series are connected in parallel to form a bridge shape. The connection point between the first check valve 22 and the second check valve 21 is communicated with the outdoor heat exchanger 14 via the expansion valve 15, and the third check valve 24 and the automatic opening / closing valve 23 are connected to each other. Is connected to the liquid via the liquid blocking valve 31. It is connected to the connection pipe 35. Here, for example, a supercooling circuit may be installed between the receiver outlet and the first check valve 22a or the third check valve 24a. You can also use! /

[0033] Next, the refrigerant flow when the outdoor unit 10a is in cooling operation, the outdoor unit 10b is stopped, the indoor unit 40a is in cooling operation, and the indoor units 40b, 40c, and 40d are stopped will be described. In the cab outdoor unit 10a, the compressor 11a is operated, the outdoor expansion valve 15a is opened, the automatic open / close valve 23a is closed, and the four-way valve 13a is set to the cooling operation side. The liquid refrigerant flowing from the outdoor expansion valve 15a passes through the second check valve 2la. Here, since the automatic opening / closing valve 23a is closed, it does not flow, and is sent to the liquid blocking valve 31a through the receiver 25a and the third check valve 24a. Since the automatic open / close valve 23a is closed during cooling operation, the bridge circuit performs the same function as the check valve. If the automatic open / close valve 23a is open, the refrigerant does not flow to the receiver 25a, and the refrigerant amount in the cycle cannot be adjusted.

 [0034] On the other hand, in the stopped outdoor unit 10b, the compressor ib is stopped, the outdoor expansion valve 15b, the automatic open / close valve 23b are closed, and the four-way valve 13b is set to the cooling operation side. The force that the high-pressure liquid refrigerant flows to the outdoor unit 10b through the liquid blocking valve 3 lb.The automatic open / close valve 23b is closed and the third check valve 24b closes the flow, so that the liquid refrigerant is supplied to the receiver 25b. Will not accumulate. Further, since the gas blocking valve 32b is pulled to the low pressure side, the refrigerant does not accumulate. Further, even when the outdoor unit 10a is defrosted, it is the same except that the four-way valve 13b is in a heating stop state. Similarly, liquid refrigerant does not accumulate in the receiver 25b of the stopped outdoor unit. FIG. 3 is a system diagram showing still another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention, and is an example of heating operation of the same refrigeration cycle as in FIG. Also in this embodiment, the stop outdoor unit closes the automatic open / close valve 23 so that liquid refrigerant does not accumulate in the stop outdoor unit. In addition, the automatic open / close valve 23 of the outdoor unit for heating operation is opened so that the bridge circuit has the same function as the check valve.

Here, the flow of the refrigerant when the operation outdoor unit 10a is in the heating operation, the outdoor unit 10b is stopped, the indoor unit 40a is in the heating operation, and the indoor units 40b, 40c, and 40d are stopped will be described. In the cab outdoor unit 10a, the compressor 11a is set to operate, the outdoor expansion valve 15a, the automatic open / close valve 23a are opened, and the four-way valve 13a is set to the heating operation side. The high-pressure liquid refrigerant from the liquid blocking valve 31a It passes through the sieve 25a and the first check valve 22a to reach the outdoor expansion valve 15a. Thus, the bridge circuit performs the same function as the check valve by opening the automatic open / close valve 23a during heating operation. If the automatic open / close valve 23a is closed, the refrigerant does not flow into the outdoor expansion valve 15a, the outdoor heat exchanger 14a, and the compressor 11a, and the suction pressure decreases and high-pressure gas refrigerant for heating cannot be supplied. .

 [0036] On the other hand, in the stopped outdoor unit 10b, the compressor ib is stopped, the outdoor expansion valve 15b, the automatic open / close valve 23b are closed, and the four-way valve 13b is set to the heating operation side. The force at which high-pressure liquid refrigerant flows up to 3 lb of liquid blocking valve The automatic open / close valve 23b is closed and the third check valve 24b closes the flow, so that liquid refrigerant accumulates in the receiver 25b. There is no. The high-pressure gas refrigerant is stopped by the gas stop valve 32b, the four-way valve 13b, the force S, and the compressor discharge side check valve 12b, and liquid refrigerant accumulates in the compressor 1 lb and the outdoor heat exchanger 14b. Flower!/,.

 FIG. 4 is a system diagram showing still another embodiment of the refrigeration cycle of the multi-type air conditioner according to the present invention, which is an example of simultaneous multi operation of cooling operation and heating operation. Also in this embodiment, the stop outdoor unit closes the automatic open / close valve 23 so that liquid refrigerant does not accumulate in the stop outdoor unit. In addition, when the gas piping of the stop outdoor unit is pulled to the low pressure side, all the four-way valves are set to the cooling mode.

 [0037] The multi-type air conditioner of this embodiment includes outdoor units 10a, 10b and indoor units 40a, 40b, 40c, 40d, three high-pressure gas connection pipes 36, low-pressure gas connection pipes 37, and liquid connection pipes 35. Each pipe is connected in parallel. Cooling / heating switching units 50a, 50b, 50c, 50d are connected to the path connecting the branch pipes of the high-pressure gas connection pipe 36 and the low-pressure gas connection pipe 37 and the gas pipes of the indoor units 40a, 40b, 40c, 40d, respectively. Is provided. This cooling / heating switching unit 50 switches the operation of the indoor unit from cooling to heating by switching the piping connected to the gas piping of the indoor unit 40 to either the high pressure gas connection piping 36 or the low pressure gas connection piping 37. It is. The cooling / heating switching unit 50 is provided with a high-pressure side open / close valve 52 on the pipe connecting the branch pipe of the high-pressure gas connection pipe 36 and the indoor unit 40, and on the pipe path connecting the branch pipe of the low-pressure gas connection pipe 37 and the indoor unit 40. A low-pressure side opening / closing valve 51 is provided.

[0038] The indoor unit 40 can perform simultaneous cooling and heating operation by setting the force S having the same configuration as in Figs. The outdoor unit 10 is different from the standard multi shown in FIG. Two outdoor heat exchangers 14 and 17 are provided, and two four-way valves 13 and 16 and two outdoor expansion valves 15 and 18 are provided accordingly. A bridge circuit including a check valve and an automatic on-off valve is formed before and after the receiver 25 as shown in FIGS. 2 and 3, but the bridge circuit may not be provided as shown in FIG.

 [0039] Next, the refrigerant flow when the outdoor unit 10a is in cooling operation, the outdoor unit 10b is stopped, the indoor unit 40a is in cooling operation, and the indoor units 40b, 40c, and 40d are stopped will be described. In the cab outdoor unit 10a, both of the outdoor expansion valves 15a and 18a are set to open, both of the four-way valves 13a and 16a are set to the cooling operation side, and the automatic opening and closing valve 23a is set to closed, which is the same as FIG. ing. The high-pressure gas refrigerant compressed by the compressor 11a passes through the compressor discharge side check valve 12a and is sent to the four-way valve 13a and the four-way valve 16a. The high-pressure gas refrigerant sent to the four-way valve 13a is sent to the outdoor heat exchanger 14a, exchanges heat with the outside air, becomes high-pressure liquid refrigerant, and is sent to the outdoor expansion valve 15a and the receiver 25a. Similarly, the high-pressure gas refrigerant sent to the four-way valve 16a is also sent to the outdoor heat exchanger 17a, exchanges heat with the outside air, becomes high-pressure liquid refrigerant, and is sent to the outdoor expansion valve 18a and the receiver 25a. The high-pressure liquid refrigerant sent to the receiver 25a passes through the liquid blocking valve 31a and the liquid connection pipe 35, is sent to the operating indoor unit 40a, is decompressed by the indoor expansion valve 42a, and is heat-exchanged by the indoor heat exchanger 41a. It becomes a low-pressure gas refrigerant. Then, it is sent to the cooling / heating switching unit 50a and sent to the low pressure side on / off valve 51a and the high pressure side on / off valve 52a.

 [0040] Here, since the low-pressure side opening / closing valve 51a is opened, the low-pressure gas refrigerant is sent to the low-pressure gas connection pipe 37, the low-pressure gas blocking valve 33a, and the compressor 11a to be recirculated. When the high-pressure side open / close valve 52a is also opened, the high-pressure gas connection pipe 36, the high-pressure gas blocking valve 32a, and the four-way valve 13a are sent to the compressor 1 la for recirculation. Here, even if all the indoor units 40 are in the cooling operation, the high pressure side on-off valve 52a is closed if the low pressure is not established through the high pressure gas connection pipe 36 and the suction side of the compressor 11a. In addition, the high-pressure side opening / closing valve 52a during cooling operation may use a solenoid valve and a check valve in parallel in addition to opening / closing by the solenoid valve. In this case, the solenoid valve may be closed and the check valve may be attached to flow from the indoor unit side to the high-pressure gas connection piping side.

Yes

[0041] On the other hand, in the stopped outdoor unit 10b, the compressor l ib is stopped, the outdoor expansion valves 15b and 18b, the automatic open / close valve 23b are closed, and the four-way valves 13b and 16b are set to the cooling operation side. For this reason, the liquid The liquid refrigerant in the connection pipe 35 flows to the outdoor unit 10b through the liquid blocking valve 31b.The automatic open / close valve 23b is closed, and the third check valve 24b The liquid refrigerant does not collect in the 25b. In addition, since the high pressure gas blocking valve 32b and the low pressure gas blocking valve 33b are both pulled to the low pressure side, liquid refrigerant will not accumulate in the compressor ib and the outdoor heat exchangers 14b and 17b.

 FIG. 5 is a system diagram showing still another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention, and is an example of the heating operation of the same refrigeration cycle as in FIG. Also in this embodiment, the stop outdoor unit closes the automatic open / close valve 23 so that liquid refrigerant does not accumulate in the stop outdoor unit. In addition, when high-pressure gas flows through the high-pressure gas connection pipe, all four-way valves of the stop outdoor unit are set to the heating mode.

 Here, the flow of the refrigerant when the outdoor unit 10a is in the heating operation, the outdoor unit 10b is stopped, the indoor unit 40a is in the heating operation, and the indoor units 40b, 40c, and 40d are stopped will be described. In the outdoor unit 10a, the compressor 11a is operated, the outdoor expansion valves 15a and 18a, the automatic open / close valve 23a are opened, and the four-way valves 13a and 16a are on the heating operation side. The high-pressure liquid refrigerant that has passed through the liquid blocking valve 31a passes through the automatic open / close valve 23a, the receiver 25a, and the first check valve 22a and reaches the outdoor expansion valves 15a and 18a. The high-pressure liquid refrigerant sent to the outdoor expansion valve 15a is depressurized and sent to the outdoor heat exchanger 14a to become low-pressure gas refrigerant, which is sent to the compressor 11a through the four-way valve 13a and recirculated. Similarly, the high-pressure liquid refrigerant sent to the outdoor expansion valve 18a is decompressed and sent to the outdoor heat exchanger 17a to become a low-pressure gas refrigerant, which is sent to the compressor 11a through the four-way valve 16a and recirculated.

On the other hand, in the outdoor unit 10b, the compressor l ib is stopped, the outdoor expansion valves 15b and 18b, the automatic opening and closing valve 23b are closed, and the four-way valves 13b and 16b are set to the heating operation side. For this reason, the liquid refrigerant in the liquid connection pipe 35 flows to the liquid blocking valve 31b.The automatic open / close valve 23b is closed, and the third check valve 24b closes the flow to the receiver 25b. Liquid refrigerant will not accumulate. The high-pressure gas refrigerant in the high-pressure gas connection pipe 36 is sent to the gas blocking valve 32b and is stopped by the compressor discharge side check valve 12b depending on the direction of the four-way valve 13b and the four-way valve 16b. The refrigerant does not accumulate in the heat exchangers 14b and 17b. Further, since the low pressure gas blocking valve 33b is pulled to the low pressure side, the liquid refrigerant does not accumulate in the compressor ib and the outdoor heat exchangers 14b and 17b. FIG. 6 is a system diagram showing still another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention, and is an example of the cooling and heating simultaneous cooling main operation of the same refrigeration cycle as in FIGS. Also in this embodiment, the stop outdoor unit closes the automatic open / close valve 23 so that liquid refrigerant does not accumulate in the stop outdoor unit. When high-pressure gas is flowing through the high-pressure gas connection pipe 36, all four-way valves of the stop outdoor unit are set to the heating mode.

 Here, the flow of the refrigerant when the outdoor unit 10a is in the cooling main operation, the outdoor unit 10b is stopped, the indoor unit 40a is in the cooling operation, the indoor unit 40b is in the heating operation, and the indoor units 40c and 40d are stopped will be described. In the outdoor operation unit 10a, the compressor 11a is operated, the outdoor expansion valve 18a is open, the automatic open / close valve 23a is closed, and the four-way valve 16a is the force set on the cooling operation side. The closed, four-way valve 13a is set to the heating operation side. The high-pressure gas refrigerant compressed by the compressor 11a passes through the compressor discharge side check valve 12a and is sent to the four-way valve 13a and the four-way valve 16a. The high-pressure gas refrigerant sent to the four-way valve 13a is sent to the high-pressure gas blocking valve 32a, the high-pressure gas connection pipe 36, and the cooling / heating switching unit 50b. Here, it is sent to the indoor unit 40b in the heating operation by the high-pressure side opening / closing valve 52b, condensed in the indoor heat exchanger 41b to become high-pressure liquid refrigerant, and sent to the indoor expansion valve 42b and the liquid connection pipe 35.

 [0047] The high-pressure gas refrigerant sent to the four-way valve 16a is sent to the outdoor heat exchanger 17a to exchange heat with the outside air to become high-pressure liquid refrigerant, and the outdoor expansion valve 18a, receiver 25a, liquid blocking valve 31a, liquid connection Sent to pipe 35. This high-pressure liquid refrigerant merges with the liquid refrigerant sent from the indoor unit 40b and is sent to the indoor unit 40a in the cooling operation. The high-pressure liquid refrigerant sent is depressurized by the indoor expansion valve 42a, becomes low-pressure gas refrigerant in the indoor heat exchanger 41a, passes through the low-pressure side on-off valve 51a in the cooling / heating switching unit 50a, and passes through the low-pressure gas connection pipe 37, low-pressure It is sent to gas stop valve 33a and compressor 11a for recirculation.

On the other hand, in the stopped outdoor unit 10b, as in FIG. 5, the compressor l ib is stopped, the outdoor expansion valves 15b and 18b, the automatic open / close valve 23b are closed, and the four-way valves 13b and 16b are set to the heating operation side. Have been. For this reason, liquid refrigerant does not accumulate in the receiver 25b, and high-pressure gas refrigerant is stopped by the compressor discharge side check valve 12b, so that refrigerant does not accumulate in the compressor ib and the outdoor heat exchangers 14b and 17b. Absent. Further, since the low-pressure gas blocking valve 33b is pulled to the low-pressure side, liquid refrigerant does not accumulate in the compressor 11b and the outdoor heat exchangers 14b and 17b. FIG. 7 is a system diagram showing still another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention, and is an example of the cooling and heating simultaneous heating main operation of the same refrigeration cycle as in FIGS. Also in this embodiment, the stop outdoor unit closes the automatic open / close valve 23, and when the high-pressure gas connection pipe is in a high pressure operation state, all the four-way valves of the stop outdoor unit are set to the heating mode.

[0050] Here, the flow of the refrigerant when the outdoor unit 10a is mainly operated for heating, the outdoor unit 10b is stopped, the indoor unit 40a is cooled, the indoor unit 40b is heated, and the indoor units 40c and 40d are stopped will be described. In the operation outdoor unit 10a, the compressor 11a is operated, the outdoor expansion valve 15a, the automatic open / close valve 23a is opened, the four-way valve 13a is the force S set on the heating operation side, and the outdoor expansion valve 18a is different from FIG. Closed or slightly opened, the four-way valve 16a is set to the cooling operation side. The high-pressure gas refrigerant compressed by the compressor 11a is sent to the high-pressure gas blocking valve 32a through the four-way valve 13a. On the other hand, a part of the high-pressure gas hardly flows through the refrigerant because the force outdoor expansion valve 18a that is sent to the outdoor heat exchanger 17a through the four-way valve 16a is closed or slightly opened. The high-pressure gas refrigerant sent to the high-pressure gas connection pipe 36 through the high-pressure gas blocking valve 32a is sent to the indoor unit 40b in the heating operation by the cooling / heating switching unit 50b and the high-pressure side opening / closing valve 52b. Then, it is condensed in the indoor heat exchanger 41b to become high-pressure liquid refrigerant, and sent to the indoor expansion valve 42b and the liquid connection pipe 35.

 [0051] A part of the liquid refrigerant sent to the liquid connection pipe 35 is sent to the indoor unit 40a in the cooling operation, depressurized by the indoor expansion valve 42a, and exchanged heat by the indoor heat exchanger 41a, and the low-pressure gas refrigerant It becomes. Then, it passes through the low pressure side opening / closing valve 51a of the cooling / heating switching unit 50a, and is sent to the low pressure gas connection pipe 37, the low pressure gas blocking valve 33a, and the compressor 11a for recirculation. The remainder of the high-pressure liquid refrigerant sent to the liquid connection pipe 35 flows into the outdoor unit 10a through the liquid blocking valve 31a, passes through the automatic open / close valve 23a, the receiver 25a, and the first check valve 22a to the outdoor expansion valve 15a. To reach. The high-pressure liquid refrigerant sent to the outdoor expansion valve 15a is depressurized, sent to the outdoor heat exchanger 14a to become a low-pressure gas refrigerant, sent to the compressor 11a through the four-way valve 13a, and recirculated.

[0052] On the other hand, in the stopped outdoor unit 10b, as in FIGS. 5 and 6, the compressor l ib is stopped, the outdoor expansion valves 15b and 18b, the automatic open / close valve 23b are closed, and the four-way valves 13b and 16b are on the heating operation side. Is set. For this reason, the high-pressure gas refrigerant that does not accumulate in the receiver 25b is stopped by the compressor discharge side check valve 12b, so that the liquid refrigerant is supplied to the compressor ib and the outdoor heat exchangers 14b and 17b. There is no accumulation of refrigerant. Further, since the low-pressure gas blocking valve 33b is pulled to the low-pressure side, liquid refrigerant does not accumulate in the compressor ib and the outdoor heat exchangers 14b and 17b.

 Brief Description of Drawings

 FIG. 1 is a system diagram showing an embodiment of a refrigeration cycle of a multi-type air conditioner of the present invention.

Yes

 FIG. 2 is a system diagram showing another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention.

 FIG. 3 is a system diagram showing another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention.

 FIG. 4 is a system diagram showing another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention.

 FIG. 5 is a system diagram showing another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention.

 FIG. 6 is a system diagram showing another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention.

 FIG. 7 is a system diagram showing another embodiment of the refrigeration cycle of the multi-type air conditioner of the present invention.

 Explanation of symbols

 [0054] 10 outdoor unit

 11 Compressor

 12 Compressor discharge side check valve

 13 Four-way valve

 14 Outdoor heat exchanger

 15 Outdoor expansion valve

 23 Automatic open / close valve

 25 receivers

 40 Indoor unit

41 Indoor heat exchanger Indoor expansion valve Cooling / heating switching

Claims

The scope of the claims  [1] Multi-type air in which a plurality of outdoor units and a plurality of indoor units are connected in parallel to a liquid connection pipe and a gas connection pipe, respectively, and a refrigerant is circulated between the plurality of outdoor units and the plurality of indoor units. In the harmony machine,  The outdoor unit includes a compressor connected to the gas connection pipe via a valve, an outdoor heat exchanger connected to the compressor, a receiver connected to the outdoor heat exchanger, and the receiver. And an automatic on-off valve provided between the liquid connection pipe and the outdoor unit is controlled so that the automatic on-off valve is closed when operation is stopped. Type Air conditioner.  [2] A plurality of outdoor units and a plurality of indoor units are connected in parallel to a liquid connection pipe, a low pressure gas connection pipe, and a high pressure gas connection pipe, respectively, and cooling is performed between the plurality of outdoor units and the plurality of indoor units. A multi-type air conditioner in which an on-off valve is provided in a piping path connecting the low-pressure gas connection pipe and the high-pressure gas connection pipe and the indoor units, wherein the outdoor unit is connected to the high-pressure gas connection A compressor connected to the pipe and the low-pressure gas connection pipe via a valve, an outdoor heat exchanger connected to the compressor, a receiver connected to the outdoor heat exchanger, the receiver and the liquid A multi-type air conditioner, wherein the outdoor unit is controlled so that the automatic open / close valve is closed when operation is stopped. Machine.  [3] The outdoor unit is  The connection between the inlet side and the outlet side of the receiver is made in order from the outlet side to a path in which a first check valve in the forward direction and a second check valve in the forward direction are connected in series from the outlet side to the inlet side. A path in which a third check valve in the direction and a fourth check valve in the forward direction are connected in series is connected in parallel to form a bridge, and the first check valve and the second check valve A connection point with the check valve is in communication with the outdoor heat exchanger, and a connection point between the third check valve and the fourth check valve is in communication with the liquid connection pipe. Prepared,  The multi-type air conditioner according to claim 1, wherein the fourth check valve is configured by the automatic opening / closing valve. [4] The automatic open / close valve of the outdoor unit is closed during cooling operation. The multi-type air conditioner described in 3.  [5] The outdoor unit is  The connection between the inlet side and the outlet side of the receiver is made in order from the outlet side to a path in which a first check valve in the forward direction and a second check valve in the forward direction are connected in series from the outlet side to the inlet side. A path in which a third check valve in the direction and a fourth check valve in the forward direction are connected in series is connected in parallel to form a bridge, and the first check valve and the second check valve A connection point with the check valve is in communication with the outdoor heat exchanger, and a connection point between the third check valve and the fourth check valve is in communication with the liquid connection pipe. Prepared,  The multi-type air conditioner according to claim 2, wherein the fourth check valve is constituted by the automatic opening / closing valve.  6. The multi-type air conditioner according to claim 5, wherein the outdoor unit has the automatic opening / closing valve closed during cooling operation.