JP3710972B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner in which a plurality of outdoor units are connected in parallel to an inter-unit pipe extending from an indoor unit.
[0002]
[Prior art]
Generally, an air conditioner in which a plurality of outdoor units and a plurality of indoor units are connected by the same system of refrigerant piping is known. In this type, each unit is connected by the same system of refrigerant pipes, so that the refrigerant stagnates in the outdoor unit that is stopped, and there is a risk that the outdoor unit that is in operation will run out of refrigerant (out of gas).
[0003]
Conventionally, when this out-of-gas condition occurs, the stopped outdoor unit is stopped and the refrigerant is recovered from the stopped outdoor unit to the operating outdoor unit using a so-called oil recovery balance pipe. Control is executed.
[0004]
[Problems to be solved by the invention]
However, in the conventional configuration, since the refrigerant is recovered from the stopped outdoor unit to the operating outdoor unit, complicated piping and a plurality of on-off valves are required, and complicated control for opening and closing each on-off valve is necessary. There is a problem of becoming.
[0005]
In the conventional configuration, the refrigerant that has fallen in the outdoor unit that is stopped is sucked and collected by the suction pressure of the compressor of the outdoor unit that is in operation using a so-called balance tube, so that it takes a long time to collect the refrigerant. There's a problem.
[0006]
Accordingly, an object of the present invention is to solve the above-described problems of the conventional technology, to reliably perform refrigerant recovery within a short time, and to simplify piping and simplify control. It is in providing the air conditioning apparatus which can be performed.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is an air conditioner in which a plurality of outdoor units and a plurality of indoor units are connected by a refrigerant pipe of the same system, and one outdoor unit being operated and the other outdoor unit being stopped are When there is a refrigerant shortage in one outdoor unit that is operating, the other outdoor unit that is stopped is operated, and the control unit that recovers the refrigerant that has fallen into the other outdoor unit to the one outdoor unit It is characterized by comprising.
[0008]
The invention according to claim 2 is an air conditioner in which a plurality of outdoor units and a plurality of indoor units are connected by refrigerant piping of the same system, and one outdoor unit being operated and the other outdoor unit being stopped are When there is a refrigerant shortage in one outdoor unit that is operating, the other outdoor unit that is stopped is operated, one outdoor unit that is operating is stopped, and the other outdoor unit is laid down Control means for collecting the refrigerant in one outdoor unit is provided.
[0009]
The invention according to claim 3 is an air conditioner in which a plurality of outdoor units and a plurality of indoor units are connected by a refrigerant pipe of the same system, and one outdoor unit being operated and the other outdoor unit being stopped are When the shortage of refrigerant occurs in one of the outdoor units that are in operation, the other outdoor unit that is in operation is operated in parallel with the one outdoor unit that is in operation for a predetermined time. And a control means for collecting the refrigerant that has fallen into the outdoor unit in one of the outdoor units.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
[0011]
In FIG. 1, 1a and 1b show outdoor units, and 3a and 3b show indoor units. The outdoor unit 1a includes an accumulator 10a, a compressor 11a driven by a gas engine, an oil separator 12a, a four-way valve 13a, an outdoor heat exchanger 14a, and an outdoor electric expansion valve 15a. Reference numeral 17a denotes a fan of the outdoor heat exchanger 14a. Since the outdoor unit 1b is the same as the outdoor unit 1a including the following configurations, the description thereof is omitted.
[0012]
The indoor unit 3a includes an indoor heat exchanger 34a and an indoor electric expansion valve 35a (hereinafter referred to as “indoor mechanical valve 35a”). Since the indoor unit 3b is the same as the indoor unit 3a including the following configuration, the description thereof is omitted. From the indoor units 3a and 3b, an inter-unit pipe consisting of a gas pipe 5 and a liquid pipe 7 extends, and outdoor units 1a and 1b are connected in parallel to the inter-unit pipe.
[0013]
The oil separator 12a separates the lubricating oil in the refrigerant discharged from the compressor 11a, and the separated lubricating oil is always returned to the compressor 11a through the oil return pipe 21a and the forced oil return pipe 22a. It is. The oil return pipe 21a is always provided with a capillary tube 24a, and flow resistance is applied to the oil returned to the compressor 11a by the capillary tube 24a. This constant oil return pipe 21a is connected to the middle of the oil separator 12a, and as long as the oil level of the oil in the oil separator 12a exceeds the position where the oil separator 12a is connected, the oil always flows through the constant oil return pipe 21a. Returned to the suction pipe. The forced oil return pipe 22a is provided with opening / closing valves 23a and 25a. The forced oil return pipe 22a is connected to the bottom of the oil separator 12a, and the oil in the oil separator 12a is forcibly returned to the suction pipe of the compressor 11a by opening the on-off valves 23a and 25a.
[0014]
The forced oil return pipes 22 a and 22 b of the outdoor units 1 a and 1 b are connected by a balance pipe 51. The balance pipe 51 is connected between the four-way valve 13a and the check valve 18a through a third auxiliary pipe 53a, and the third auxiliary pipe 53a is provided with a third on-off valve 55a.
[0015]
When the third on-off valve 55a is opened and the four-way valve 13a is switched to the position shown in the drawing, the balance pipe 51 communicates with the outdoor heat exchanger 14a.
[0016]
In the air conditioner having the above-described configuration, in this embodiment, a suction temperature sensor Sa for detecting the refrigerant suction temperature of the compressors 11a and 11b and a discharge temperature sensor Sb for detecting the refrigerant discharge temperature of the compressors 11a and 11b are provided. Then, a shortage of refrigerant (out of gas) in the outdoor units 1a and 1b is detected by the sensors Sa and Sb.
[0017]
That is, when the gas shortage occurs, the refrigerant temperature in the outdoor units 1a and 1b rises and the detection temperature of each sensor Sa and Sb rises. Therefore, if the detected temperature rises above a certain temperature, Is detected.
[0018]
Next, refrigerant recovery between outdoor units will be described.
[0019]
In this embodiment, it is assumed that one outdoor unit that is operating and the other outdoor unit that is stopped exist in the same system. This is because the control is to recover the refrigerant that has fallen into the other outdoor unit that is stopped.
[0020]
FIG. 3 is a processing flow at the time of refrigerant recovery.
[0021]
First, it is determined whether there is one outdoor unit (for example, the outdoor unit 1a) in operation and the other outdoor unit (for example, the outdoor unit 1b) that is stopped (S1). Control is not performed. When both units exist, it is determined whether or not the out of gas is generated in one outdoor unit 1a during operation (S2). In this determination, when the detected temperature of each of the sensors Sa and Sb rises above a certain temperature, it is determined that a gas shortage has occurred.
[0022]
When the out-of-gas condition occurs in one outdoor unit 1a during operation, the other outdoor unit 1b during operation is operated in order to recover the refrigerant from the other outdoor unit 1b during operation (S3). At the same time, the other outdoor unit 1b and the one outdoor unit 1a in operation are operated in parallel (S4).
[0023]
Then, for example, it is determined whether or not 5 minutes have passed (S5), and parallel operation is executed until 5 minutes have passed.
[0024]
In this oil recovery control, since the outdoor unit 1b that is stopped is forcibly operated in addition to the outdoor unit 1a that is in operation, the overall capacity on the outdoor unit side is the required capacity on the indoor unit side. This is because the capacity increases and the balance of the ability is lost, and the operation can be continued only for a maximum of about 5 minutes.
[0025]
In this embodiment, by performing the above-described refrigerant recovery control, the refrigerant moves as shown by the dotted arrow in FIG. 1 (refrigerant circuit during cooling operation), and the refrigerant has fallen into the other outdoor unit 1b. Is recovered in one outdoor unit 1a in which a gas shortage has occurred. That is, the refrigerant has slept in the outdoor heat exchanger 14b of the other outdoor unit 1b, and the refrigerant that has slept here is swept away by the discharge pressure of the compressor 11b, and moves from there as indicated by the dotted arrow, It flows in the order of the indoor units 3a and 3b, the four-way valve 13a of one outdoor unit 1a, and the accumulator 10a, and is collected in the suction pipe of the compressor 11a.
[0026]
In this case, the refrigerant pressure of the outdoor unit 1b in which the refrigerant lies is higher than the refrigerant pressure of the outdoor unit 1a in which the lack of gas has occurred. Therefore, during the recovery of the refrigerant, the refrigerant does not flow into the outdoor unit 1b in which the refrigerant is sleeping, and most of the refrigerant is recovered in the outdoor unit 1a in which the lack of gas has occurred. The load factor between 1a and 1b is constant.
[0027]
FIG. 2 is a refrigerant circuit diagram during heating operation. The processing flow shown in FIG. 3 is the same for both the cooling process and the heating process. When the process is executed, the refrigerant moves as shown by the dotted arrow in FIG. The refrigerant that has fallen into the unit 1b is collected in the one outdoor unit 1a that has run out of gas.
[0028]
Also in this case, the refrigerant is sleeping in the outdoor heat exchanger 14b of the other outdoor unit 1b. When this air conditioning system is operated for heating, the refrigerant from the compressor 11b of the outdoor unit 1b moves through the four-way valve 13b as indicated by the dotted arrows, and the indoor units 3a and 3b, the indoor units of one of the outdoor units 1a. The electric expansion valve 15a, the outdoor heat exchanger 14a, the four-way valve 13a, and the accumulator 10a flow in this order and are returned to the suction pipe of the compressor 11a.
[0029]
In this case, since the refrigerant pressure of the outdoor unit 1b in which the refrigerant lies is higher than the refrigerant pressure of the outdoor unit 1a in which the lack of gas occurs, the outdoor unit 1a in which most of the refrigerant has been out of gas during the recovery of the refrigerant. And the load factor between the outdoor units 1a and 1b becomes constant after the parallel operation for a predetermined time.
[0030]
In this embodiment, since the refrigerant hardly returns to the outdoor unit 1b in which the refrigerant is sleeping, the refrigerant sleeping in the outdoor heat exchanger 14b is sucked out by the suction pressure of the compressor 11b, and is indicated by a dotted arrow. Then, the four-way valve 13b and the accumulator 10b flow in this order, returned to the suction pipe of the compressor 11b, discharged from the compressor 11b, and, as described above, into the suction pipe of the compressor 11a of one outdoor unit 1a. Collected.
[0031]
In this embodiment, since the refrigerant is moved in the normal operation mode during the cooling operation and the heating operation, the refrigerant can be recovered in a short time compared to the control in which the suction is recovered by the suction pressure of the conventional compressor. Can do.
[0032]
In addition, since the refrigerant is normally moved through the refrigerant circuit, complicated piping and a plurality of on-off valves are not required as in the conventional case, and complicated control for opening and closing each on-off valve is also required. Down is planned.
[0033]
In the above-described embodiment, the outdoor unit in which the lack of gas has occurred and the outdoor unit in which the refrigerant has fallen are operated in parallel for a predetermined time of about 5 minutes during the refrigerant recovery control. It is also possible to operate only the outdoor unit that has run out of gas.
[0034]
As described above, the refrigerant pressure of the outdoor unit 1a in which the gas shortage has occurred is lower than the refrigerant pressure of the outdoor unit 1b in which the refrigerant has stagnated.
[0035]
Accordingly, during the cooling operation, referring to FIG. 1, the refrigerant that has passed through the indoor unit 3 does not return to the outdoor unit 1b in which the refrigerant has fallen, but is mostly returned to the outdoor unit 1a in which the gas has run out. According to this, even if the outdoor unit 1a in which the gas shortage occurs is stopped, the refrigerant can be recovered from the outdoor unit 1b due to the refrigerant pressure difference between the outdoor units 1a and 1b.
[0036]
When the refrigerant recovery is performed by stopping the outdoor unit 1a where the gas shortage has occurred during the heating operation, the indoor electric expansion valve 15a is opened with reference to FIG. As described above, the return refrigerant from the indoor unit is returned to the outdoor unit 1a in which almost no gas is generated. Therefore, if the indoor electric expansion valve 15a is opened, outdoor heat exchange is performed with the pressure of the return refrigerant. 14a, the four-way valve 13a, and the accumulator 10a flow in this order and are collected in the suction pipe of the compressor 11a.
[0037]
According to this, even if the outdoor unit 1a in which the gas shortage occurs is stopped, the refrigerant can be recovered from the outdoor unit 1b due to the refrigerant pressure difference between the outdoor units 1a and 1b.
[0038]
As mentioned above, although this invention was demonstrated based on one Embodiment, it is clear that this invention is not limited to this.
[0039]
【The invention's effect】
In the present invention, since the refrigerant is moved in the normal operation mode during the cooling operation and the heating operation, the refrigerant can be recovered in a shorter time compared to the control for suction recovery using the suction pressure of the conventional compressor. it can.
[0040]
In addition, since the refrigerant is normally moved through the refrigerant circuit, complicated piping and a plurality of on-off valves are not required as in the conventional case, and complicated control for opening and closing each on-off valve is also required. Down is planned.
[Brief description of the drawings]
FIG. 1 is a system diagram at the time of cooling operation showing an example of an air conditioner according to the present invention.
FIG. 2 is a system diagram similarly during heating operation.
FIG. 3 is a flowchart illustrating a processing flow according to an embodiment.
[Explanation of symbols]
1a, 1b Outdoor unit 3a, 3b Indoor unit 5 Gas pipe 7 Liquid pipe 10a, 10b Accumulator 11a, 11b Compressor 12a, 12b Oil separator 14a, 14b Outdoor heat exchanger 21a, 21b Return pipe Sa, Sb sensor

Claims (3)

In an air conditioner in which a plurality of outdoor units and a plurality of indoor units are connected by refrigerant piping of the same system,
If there is one outdoor unit that is in operation and the other outdoor unit that is in operation and there is a shortage of refrigerant in one outdoor unit that is in operation, the other outdoor unit that is in operation is operated and the other outdoor unit is operated. An air conditioner comprising a refrigerant recovery control means for recovering the refrigerant that has fallen into the outdoor unit to one outdoor unit. In an air conditioner in which a plurality of outdoor units and a plurality of indoor units are connected by refrigerant piping of the same system,
If there is one outdoor unit that is in operation and the other outdoor unit that is in operation and there is a shortage of refrigerant in one outdoor unit that is in operation, the other outdoor unit that is in operation is operated, An air conditioner comprising: a refrigerant recovery control means for stopping the outdoor unit and recovering the refrigerant that has fallen into the other outdoor unit to one outdoor unit. In an air conditioner in which a plurality of outdoor units and a plurality of indoor units are connected by refrigerant piping of the same system,
If there is one outdoor unit that is in operation and the other outdoor unit that is in operation and there is a shortage of refrigerant in one outdoor unit that is in operation, the other outdoor unit that is in operation is operated, An air conditioner comprising refrigerant recovery control means for operating in parallel with the outdoor unit for a predetermined time and recovering the refrigerant sleeping in the other outdoor unit to one outdoor unit.

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