JP2005315445A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compression type air conditioner capable of circulating a refrigerant without using a mechanical means such as a positive displacement pump in indirect outside air cooling operation, and not excessively complicating a structure. <P>SOLUTION: This air conditioner comprises a main circuit and a driving circuit 2, and the main circuit comprises a main compressor 11, an outdoor heat exchanger (14 and fan 13), a decompressing means (decompression valve Vx1), and an indoor heat exchanger (32 and fan 31). The refrigerant vapor is passed in the driving circuit 2, and the driving circuit 2 has refrigerant tanks T1, T2 communicated with the main circuit, and storing the refrigerant circulated in the main circuit, and a compressor for driving 21 for supplying the refrigerant vapor to the refrigerant tanks T1, T2. The liquid refrigerant circulated in the main circuit is sucked into the refrigerant tank (for example, T1) communicated with a suction side of the compressor for driving 21, and the liquid refrigerant stored in the refrigerant tank (for example, T2) communicated with a discharge side of the compressor for driving 21 is pushed out to a main circuit side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air conditioner, and more particularly to an air conditioner using a compression refrigeration cycle.

  As an indoor cooling method, there is an air conditioner using a compression refrigeration cycle. An air conditioner with an improved compression refrigeration cycle. A refrigerant pump is provided between the outdoor heat exchanger and the indoor heat exchanger. When the outside air temperature is low, the refrigerant is circulated through the refrigerant pump without operating the compressor. There are things that can be operated by cooling. This method is called indirect outside air cooling because the refrigerant is once cooled with the outside air and the indoor cooling is performed with the cooled refrigerant. In some cases, water is used as a circulation medium. However, if a refrigerant is used, the phase change can be used, so that the pump power can be saved by reducing the circulation amount. A cooling cycle in indirect outside air cooling (for example, refer to Patent Document 1) will be briefly described below.

  In FIG. 13, the refrigerant vapor exiting the evaporator 4 is sent to the condenser 8 as it is, cooled in the condenser 8 by the low-temperature outside air, condensed, and sent to the refrigerant pump 1. In the refrigerant pump 1, the liquid refrigerant is pressurized and guided to the evaporator 4. In the evaporator 4, the refrigerant evaporates by cooling the room air and returns to the condenser 8 again. Thereafter, this cycle is repeated, and indoor heat is released by releasing indoor heat into the atmosphere via the evaporator 4 and the condenser 8.

However, in a conventional air conditioner capable of performing an indirect outside air cooling operation performed by a refrigerant pump, cavitation is likely to occur in the refrigerant pump, and the pump performance and the durability are easily deteriorated.
In addition, the pump must handle the head of the density difference between the liquid and the gas, but there are few pumps that can handle that number of heads.
If it is a positive displacement pump like a gear pump, such a head can be held (for example, refer to patent documents 2).

In the prior art having a positive displacement pump such as a gear pump, the components are operated in contact with each other, particularly like a gear of a gear pump.
Even in such a configuration, there is no problem as long as it is a pump for lubricating oil, but in the case of an air conditioner, the fluid flowing through the pump is a refrigerant.
The refrigerant has poor lubricity, and the material of the component parts such as gears wears, and the durability of the air conditioner becomes a problem.

On the other hand, there is a conventional technique in which a pressure difference is generated in the secondary refrigerant by a temperature difference generated by heat and the secondary refrigerant is circulated by the pressure difference (for example, Patent Document 3).
However, such a conventional technique has a complicated structure and is problematic in terms of cost.
JP 2002-61918 A JP 2001-165061 A JP 2001-336851 A

  The present invention has been proposed in view of the above-described problems of the prior art, and during indirect outdoor air cooling operation, the refrigerant can be circulated without using mechanical means such as a positive displacement pump, And it aims at provision of the air-conditioner which a structure does not become too complicated.

  The air conditioner of the present invention includes a main circuit and a drive circuit (2), and the main circuit includes a main compressor (11), an outdoor heat exchanger (14 and a fan 13), and pressure reducing means (pressure reducing valve Vx1). ) And an indoor heat exchanger (32 and fan 31), the refrigerant vapor flows through the drive circuit (2), and stores the refrigerant that communicates with the main circuit and circulates through the main circuit. A refrigerant that is provided with a tank (T1, T2) and a driving compressor (21) that supplies refrigerant vapor to the refrigerant tank (T1, T2) and communicates with a suction side of the driving compressor (21). The liquid refrigerant circulating through the main circuit is sucked into the tank (eg, T1) and the liquid refrigerant accumulated in the refrigerant tank (eg, T2) communicating with the discharge side of the driving compressor (21) is pushed out to the main circuit side. (Claim 1).

  Here, circuit switching means (for example, on-off valves V1 to V4) are interposed in the drive circuit, and the suction side and discharge side of the drive compressor (21) and the refrigerant tanks (T1, T2) are connected. The communication is switched by the circuit switching means (for example, on-off valves V1 to V4) when the refrigerant tank (one of T1 and T2) becomes empty or the refrigerant tank (the other of T1 and T2) is filled with liquid refrigerant. It is preferable that the suction side and the discharge side of the drive compressor 21 are switched to communicate with either of the refrigerant tanks T1 and T2 by switching the open / closed state (Claim 2: FIG. 2). 1, FIG. 2).

  In the present invention, the drive circuit includes a cooling means for cooling the refrigerant vapor (for example, the liquid stored in at least one of the heat exchanger 27 and the cooling fan 26 or the refrigerant tanks T1 and T2 shown in FIGS. 6 and 7). It is preferable that a structure for allowing the refrigerant vapor to pass through the refrigerant is provided (Claim 3: FIGS. 3 to 7).

  In the present invention, a low-pressure refrigerant tank (16) is interposed in a region between the indoor heat exchanger (32) of the main circuit and the main compressor (11), and the lubricating oil flowing through the main circuit is captured. It is preferable to provide a circuit (line Lm11, on-off valve Vb2) for communicating the low-pressure refrigerant tank (16) (the bottom thereof) with the suction side of the driving compressor (21) (Claim 4: FIGS. 8 and 10). ).

Alternatively, in the present invention, the lubricating oil catching means (for example, the oil separator 12) is provided on the discharge side of the main compressor (11), and the lubricating oil catching means (for example, the oil separator 12) and the driving compressor (21) are provided. It is preferable to provide a circuit (line Lm12, on-off valve Vb2) that communicates with the suction side (Claim 5: FIGS. 9 and 10).
In this case, the circuit (line Lm12, on-off valve Vb2) that communicates the lubricating oil capturing means (12) and the suction side of the drive compressor (21) is branched (Bm4), and the discharge side of the main compressor (11) It is preferable to provide a circuit (Lm13 and bypass valve Vb3) communicating with the valve.

In addition, in the present invention, it is preferable to provide means (purge means) for supplying refrigerant vapor circulating in the drive circuit to the main circuit side (Claim 6: FIGS. 11 to 13).
Specifically, a circuit (line Ls13, bypass valves Vb4, Lm12, bypass valve Vb2) that connects the discharge side of the drive compressor (21) to the main circuit may be provided. Alternatively, by switching circuit switching means (for example, on-off valves V1 to V4) for switching communication between the refrigerant tanks (T1, T2) and the discharge side or suction side of the driving compressor (21), the refrigerant vapor (at least one) It may be configured to be supplied to the main circuit via the refrigerant tanks (T1 and / or T2).

According to the air conditioner of the present invention having the above-described configuration (Claims 1 and 2), in the case of indirect outside air cooling or the like, the refrigerant tank (for example, T1) communicated with the suction side of the driving compressor (21). Since the liquid refrigerant circulating in the main circuit is sucked in and the liquid refrigerant accumulated in the refrigerant tank (for example, T2) communicated with the discharge side of the driving compressor (21) is sent to the main circuit side, the main compressor ( If the driving compressor (21) is operated without operating 11), the refrigerant circulates in the main circuit.
Therefore, for example, during the indirect outdoor air cooling operation, it is only necessary to stop the main compressor (11) and operate only the drive compressor (21), and energy for operation is saved.
In addition to this, it is the refrigerant vapor that flows through the drive circuit (2), and the mass flow rate of the refrigerant vapor can be 1/20 of the mass flow rate of the liquid refrigerant, as will be described later. Accordingly, the power required for the operation of only the driving compressor (21) is much less than the power required for operating the main compressor (11) during the indirect outside air operation, and a request for energy saving is required. It matches well.

  There is no problem of wear unless the drive compressor (21) is depleted of lubricating oil. Furthermore, since it is not too complicated mechanically, the probability of failure is low.

The refrigerant vapor circulating in the drive circuit is compressed by the drive compressor (21), presses the liquid refrigerant in the refrigerant tanks (T1, T2), and then is sucked into the drive compressor (21) again and compressed. The energy obtained by the compression is not dissipated anywhere. Therefore, the refrigerant vapor may be overheated.
On the other hand, if the driving circuit is provided with a cooling means for cooling the refrigerant vapor circulating through the driving circuit (Claim 3), the danger of refrigerant vapor overheating can be prevented. .

Here, the lubricating oil mixed in the refrigerant circulating in the driving circuit may move to the main circuit side via the refrigerant tanks (T1, T2), but the lubricating oil moved to the main circuit side is again used for driving. Since it does not return to the compressor (21), the drive compressor (21) may cause a problem of running out of lubricating oil.
On the other hand, in the present invention, a low-pressure refrigerant tank (16) is interposed in a region between the indoor heat exchanger (32) of the main circuit and the main compressor (11), and the low-pressure refrigerant tank (16). If a circuit (line Lm11, on-off valve Vb2) that communicates with the suction side of the drive compressor (21) is provided (Claim 4), lubrication mixed in the refrigerant circulating on the main circuit side Since the oil is captured by the low-pressure refrigerant tank (16), the lubricating oil returns to the suction side of the drive compressor (21). As a result, it is possible to prevent the drive compressor (21) from running out of lubricating oil.

Furthermore, in the present invention, a lubricating oil catching means (for example, an oil separator 12) is provided on the discharge side of the main compressor (11), and the lubricating oil catching means (for example, the oil separator 12) and a driving compressor ( If a circuit (line Lm12, on-off valve Vb2) that communicates with the suction side of the driving compressor 21) is provided (Claim 5), the lubricating oil is used in the low-pressure refrigerant tank (16) (described in relation to Claim 4). Even when the main compressor (11) is temporarily driven, the lubricating oil contained in the refrigerant gas discharged from the main compressor (11) is converted into the lubricating oil capturing means (for example, oil Since it is reliably captured by the separator 12), it is possible to more reliably prevent the lubricating oil deficiency of the driving compressor (21). That is, if the drive compressor (21) runs out of lubricating oil, the drive compressor (21) is stopped and the main compressor (11) is operated. Then, the lubricating oil mixed in the main circuit is captured by the lubricating oil capturing means (for example, the oil separator 12) and stored. Thereafter, a circuit (line Lm12, on-off valve Vb2) that communicates the lubricating oil capturing means (eg oil separator 12) and the suction side of the drive compressor (21) (for example, by opening on-off valve Vb2) If the communication state is established, the lubricating oil stored in the lubricating oil trapping means (for example, the oil separator 12) can be supplied to the driving compressor (21).
After the lubricating oil is sufficiently supplied to the driving compressor (21), the main compressor (11) is stopped and the lubricating oil capturing means (for example, the oil separator 12) and the suction of the driving compressor (21) are sucked. The circuit (line Lm12, on-off valve Vb2) communicating with the side may be closed (for example, by closing on-off valve Vb2), and the indirect outside air cooling operation may be started again.
During the operation of the main compressor (11), the air conditioner of the present invention functions as a normal compression refrigeration cycle and can continue the cooling operation. Therefore, the cooling operation is not stopped.

Further, a circuit (Lm13) that communicates a circuit (line Lm12, on-off valve Vb2) that communicates the lubricating oil catching means (12) with the suction side of the driving compressor (21) with the discharge side of the main compressor (11). If the on-off valve Vb3) is provided, the drive compressor (21) becomes deficient in lubricating oil, and when the main compressor (11) is operated, it is stored in the lubricating oil trapping means (for example, the oil separator 12). In addition to the lubricating oil, the lubricating oil accumulated in the circuit (line Lm12) that connects the lubricating oil capturing means (for example, the oil separator 12) and the suction side of the driving compressor (driving compressor 21) is also on the driving circuit side. To prevent the lubricant from running out.
Specifically, the circuit (Lm13) communicating with the discharge side of the main compressor (11) is brought into a communication state (opening the on-off valve Vb3), and is discharged from the main compressor (11). Lubricating oil accumulated in a circuit (line Lm12) that communicates the lubricating oil capturing means (for example, the oil separator 12) and the suction side of the driving compressor (driving compressor 21) by the high-pressure refrigerant vapor Purge.

When the refrigerant tank communicates with the driving compressor suction side, the inside of the refrigerant tank is depressurized, so that the liquid refrigerant in the refrigerant tank partially evaporates. As a result, there is a possibility that the refrigerant filling amount circulating in the drive circuit increases and the entire drive circuit is boosted.
On the other hand, if a means (purge means) for supplying the refrigerant vapor circulating in the drive circuit to the main circuit side is provided (Claim 6), the increased refrigerant vapor is purged to the main circuit side, whereby the drive circuit It is possible to keep the charging amount of the refrigerant circulating through the constant, and to prevent the entire drive circuit from being boosted.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, a first embodiment of the present invention will be described with reference to FIG.
In FIG. 1, the air conditioner includes a heat source unit 1, a drive circuit 2, and an indoor unit 3 as a large unit.

  The heat source unit 1 includes a main compressor 11, a first oil separator 12, an outdoor heat exchanger 14 including an outdoor fan 13, a high-pressure refrigerant tank 15, and a first low-pressure refrigerant tank 16. The main circuit, which will be described later, is configured such that the refrigerant circulates through the indoor unit 3 having the first pressure reducing valve Vx1 and including the indoor fan 31 and the indoor heat exchanger 32.

The devices (11 to 16) constituting the heat source device 1 are connected by a refrigerant line described below to form a main circuit of the air conditioner.
That is, the main compressor 11 and the first oil separator 12 are connected by a line Lm1, and the first oil separator 12 and the indoor heat exchanger 14 are connected by a line Lm3 across the line Lm2 and the first junction Gm1. It is connected. The indoor heat exchanger 14 and the high-pressure refrigerant tank 15 are connected by a line Lm4, and the first connection point J1 between the high-pressure tank 15 and a drive circuit described later is connected by a line Lm5.

  Further, a second connection point J2 to the drive circuit described later and the indoor heat exchanger 32 are connected by a line Lm6 having the first pressure reducing valve Vx1 interposed therebetween, and the indoor heat exchanger 32 and the first low pressure are connected. The refrigerant tank 16 is connected by a line Lm7. The first low-pressure refrigerant tank 16 and the main compressor 11 are connected by a line Lm8, a first branch point Bm1, a line Lm9, a second branch point Bm2, and a line Lm10 in the flow order.

The first branch point Bm1 and the first junction point Gm1 are connected by a first bypass line Lb1 with a bypass valve Vb interposed therebetween. By opening the bypass valve Vb, a part of the refrigerant passes through the main compressor 11. It is configured to bypass.
The second branch point Bm2 and the first oil separator 12 are connected to each other by a second bypass line Lb2 with a first resistor 17 interposed therebetween.

  On the other hand, the drive circuit 2 includes a drive compressor 21, a second oil separator 22, first to fourth on-off valves V1 to V4, first and second refrigerant tanks T1 and T2, The first to fourth check valves Vc1 to Vc4, the second pressure reducing valve Vx2, and the second low pressure refrigerant tank 23 are connected to each other by a line described below, and the air conditioner A drive circuit is formed.

  That is, the line Ls1 is connected to the discharge side of the drive compressor 21, and the line Ls1 branches into a line Ls2 and a line Ls12 at the first branch point Bs1 on the drive side, and the line Ls2 is the second oil. Connected to the inflow side of the separator 22. A line Ls3 is connected to the discharge side of the second oil separator 22, and the line Ls3 is connected to the line Ls4 and the second on-off valve V4 which are provided with the second on-off valve V2 at the second branch point BS2. The line Ls4 is connected to the first refrigerant tank T1. On the other hand, the line Ls5 is connected to the second refrigerant tank T2.

Further, the first refrigerant tank T1 is connected to a line Ls6 having a first on-off valve V1, and the second refrigerant tank T2 is connected to a line Ls7 having a third on-off valve V3. Yes. The line Ls6 and the line LS7 join at the first joining point Gs1 on the drive circuit side and are connected to the line Ls8.
A second pressure reducing valve Vx <b> 2 is interposed in the line Ls <b> 8, and the other end is connected to the second low pressure refrigerant tank 23.

  The second low-pressure refrigerant tank 23 is connected to the driving compressor 21 via a line Ls9, a second junction Gs2, a line Ls10, a third junction Gs3, and a line Ls11.

  The first branch point Bs1 and the third junction point Gs3 are connected by the line Ls12 having a resistor 24 interposed therebetween, and the second oil separator 22 and the second junction point Gs2 are resistors. 25 is connected by a line Ls13. Here, as the resistors 24 and 25, for example, capillary tubes are used.

A line Ls14 is connected to the lower side of the first refrigerant tank T1 in the figure, and the line Ls14 branches into a line Ls15 and a line Ls16 at a third branch point Bs3. The line Ls15 is connected to the closing side of the first check valve Vc1, and the line Ls16 is connected to the opening side of the second check valve Vc2.
On the other hand, a line Ls17 is connected to the lower side of the second refrigerant tank T2 in the figure, and the line Ls17 branches into a line Ls18 and a line Ls19 at a fourth branch point Bs4. The line Ls18 is connected to the closing side of the third check valve Vc3, and the line Ls19 is connected to the opening side of the fourth check valve Vc4.

The open side of the first check valve Vc1 is connected to the first connection point J1 with the main circuit side by a line Ls21, and the close side of the second check valve Vc2 is connected to the main circuit side by a line Ls22. It is connected to the second connection point J2.
The open side of the third check valve Vc3 is connected to the first connection point J1 with the main circuit side by a line Ls23, and the close side of the fourth check valve Vc4 is connected to the main circuit side by a line Ls24. Are connected to the second connection point J2.

  The first to fourth on-off valves V1 to V4 are connected to the control unit 50 through control signal lines So, respectively, and are configured to control the opening and closing of the valves according to commands from the control unit 50.

Here, the operation at the time of normal cooling where the outside air temperature is high will be described with reference to FIG.
When the outside air temperature is high, it is operated as a compression refrigeration cycle. That is, without operating the drive compressor 21 on the drive circuit 2 side, the first to fourth on-off valves V1 to V4 are all closed, the bypass valve Vb of the heat source unit 1 is closed, and the main compressor 11 is operated. The refrigerant flowing through the main circuit is pressurized by the main compressor 11 and sent to the outdoor unit 14 as a high-temperature and high-pressure gas. In the outdoor unit 14, the high-temperature and high-pressure refrigerant vapor is condensed by exchanging heat with the outside air. The liquid refrigerant is depressurized by the first pressure reducing valve (expansion valve) Vx1, evaporated in the indoor unit (evaporator) 32, the indoor air is cooled by the heat of vaporization at that time, returned to the main compressor 11, and again in the same manner. Repeat the cycle.

When the outside air temperature is sufficiently low, the driving circuit 2 supplies the conveyance power to the refrigerant by the following principle, the heat source unit 1 and the indoor unit 3 are circulated by the main circuit, and the room is cooled by indirect outside air cooling.
First, when the outside air temperature becomes equal to or lower than a predetermined temperature, the control unit 50 stops the main compressor 11 and opens the bypass valve Vb to operate the outdoor fan 13. The first and fourth on-off valves V1 and V4 on the drive circuit 2 side are opened, and the second and third on-off valves V2 and V3 are closed. At this time, since the outside air temperature is sufficiently low, the refrigerant is cooled and condensed by the outdoor heat exchanger 14.

  On the other hand, the driving compressor 21 sucks the refrigerant vapor in the first refrigerant tank T1 through the first on-off valve V1, the second pressure reducing valve (expansion valve) Vx2, and the line Ls8 on the driving circuit 2 side. At this time, since the second on-off valve V2 is closed, the first tank T1 is decompressed. Thereby, the liquid refrigerant cooled by the outdoor heat exchanger 14 flows into the tank T1 through the first check valve Vc1.

  The driving compressor 21 sends out the discharge gas (refrigerant) via the second oil separator 22 and the fourth on-off valve V4. As described above, at this time, the third on-off valve V3 is closed. Therefore, the pressure of the second refrigerant tank T2 is increased.

When the pressure of the second refrigerant tank T2 is increased, the liquid refrigerant stored in the second refrigerant tank T2 is sent to the indoor heat exchanger 32 of the indoor unit 2 through the fourth check valve Vc4. After that, when the second refrigerant tank T2 becomes empty or the first refrigerant tank T1 becomes full, the on-off valve is automatically switched. That is, the opened first and fourth open / close valves V1 and V4 are closed, and the closed second and third open / close valves V2 and V3 are opened.
As a result, the liquid refrigerant in the first refrigerant tank T1 is sent to the indoor heat exchanger 32, and the second refrigerant tank T2 sucks the liquid refrigerant from the heat source unit 1.

  By repeating the above cycle, the refrigerant circulates between the outdoor heat exchanger 14 and the indoor heat exchanger 32.

  The valve opening / closing switching timing is based on detection of the liquid level (level) of the liquid refrigerant in the refrigerant tanks T1 and T2. Conventionally and well-known techniques may be applied to open / close switching of the on-off valves V1 to V4 by detecting the liquid level (level) of the liquid refrigerant in the refrigerant tanks T1 and T2.

  Since the main compressor 11 of the heat source unit 1 is stopped and the bypass valve Vb is opened, the refrigerant vapor evaporated in the indoor heat exchanger 32 is once stored in the first low-pressure refrigerant tank 16, It flows into the outdoor unit 14 via the line Lm8, the first branch point Bm1, the first bypass Lb1, and the first junction Gm1. That is, since the main compressor 11 is not operating, energy for operating the main compressor 11 can be saved.

  Here, the resistor (for example, capillary tube) 24 interposed in the drive circuit on the drive circuit 2 side is configured so that the pressure in the refrigerant tank (T1 or T2) and the drive compressor 21 are In some cases, the pressure difference between the discharge pressure and the suction pressure becomes very large, and in order to prevent various problems associated with sudden pressure fluctuations in such a case, the discharge port and the suction port of the compressor 21 are bypassed to provide an appropriate fluid. Provided to provide resistance.

  Further, the line Ls13 with the resistor 25 interposed therein prevents the lubricating oil accumulated in the second oil separator 22 from returning to the driving compressor 21, thereby preventing the driving compressor 21 from running out of lubricating oil. It is a circuit for.

According to the air conditioner of the first embodiment described above, in order to press the liquid refrigerant in the refrigerant tank (T1 or T2) to the main circuit side, the liquid may be replaced with the same volume of refrigerant vapor.
If the volume is the same, the mass of the refrigerant vapor is smaller than 1/20 of the mass of the liquid refrigerant. For example, the refrigerant is R410A (currently the most commonly used refrigerant for air conditioning), the refrigerant vapor discharged from the driving compressor is 1.443 MPa (saturation temperature, equivalent to 20 ° C.), and the temperature is 50 ° C. (compressor). When the liquid refrigerant in a saturated state is pressed by the refrigerant vapor at the same pressure as the refrigerant vapor (refrigerant vapor discharged from the compressor), the density of the refrigerant vapor Is 46.14 kg / m ³ , whereas the density of the liquid refrigerant is 1085 kg / m ³ , and the density ratio is 20 times or more.
As a result, the mass flow rate circulated by the drive compressor 21 can be 1/20 or less that of the main compressor 11. That is, it meets the demand for energy saving.

Next, a second embodiment will be described with reference to FIG.
The second embodiment of FIG. 2 omits the second lubricating oil capturing means 22 and the line Ls13 from the driving compressor 21 of the first embodiment of FIG. This is an embodiment in which an oil level sensor S for detection is attached, and other configurations and operational effects are substantially the same as those of the first embodiment of FIG.

Next, a third embodiment will be described with reference to FIG.
In the first embodiment of FIG. 1 and the second embodiment of FIG. 2 described above, the refrigerant vapor circulating through the drive circuit 2 is driven by “compressing and pressing the liquid refrigerant in the refrigerant tank (T1 or T2). However, the energy obtained by the compression is not dissipated anywhere. As a result, the temperature immediately rises.
In other words, the refrigerant vapor of the drive circuit 2 is always sucked into the drive compressor 21 and is repeatedly discharged, and does not pass through the cooling mechanism or the like. Therefore, the temperature rises immediately. As a result, there is a problem that the refrigerant vapor circulating in the drive circuit immediately rises to a dangerous temperature range.
The third embodiment shown in FIG. 3 solves this problem.

In FIG. 3, an outdoor heat exchanger 27 for the drive circuit and having an outdoor fan 26 is interposed in the refrigerant line Ls3 (a line connecting the second oil separator 22 and the on-off valves V1 to V4). That is, the refrigerant vapor having the highest temperature discharged from the drive compressor 21 is cooled by the outdoor heat exchanger 27 and the outdoor fan 26 for the drive circuit. By doing so, the temperature rise of the refrigerant circulating in the drive circuit is prevented.
In other words, in the third embodiment of FIG. 3, overheating of the refrigerant vapor circulating through the driving compressor 21 can be prevented by cooling the refrigerant at the discharge port of the driving compressor 21.

  As a point to be noted when the outdoor heat exchanger 27 of the drive circuit is cooled by the outdoor fan 26, the discharge pressure of the drive compressor 21 and the outlet temperature of the outdoor heat exchanger 27 are sensors (the temperature sensor 28 interposed in the line Ls3 and the temperature sensor 28). By monitoring with the pressure sensor 29) and maintaining the outlet temperature of the outdoor heat exchanger 27 to exceed the saturation temperature of the discharge pressure of the driving compressor 21, it is possible to prevent the refrigerant from condensing in the outdoor heat exchanger 27. desirable.

  That is, if the refrigerant vapor circulating in the drive circuit is condensed, “the mass flow rate of the refrigerant circulating in the drive circuit is less than 1/20 of the mass flow rate of the refrigerant circulating in the main circuit. The advantage of saving energy is lost. Therefore, the outdoor fan 26 is controlled so that the temperature at the outlet of the outdoor heat exchanger 27 of the drive circuit becomes higher than the refrigerant saturation temperature, and the cooled refrigerant is maintained in a gas phase state without condensing, that is, proper It is necessary to control the rotational speed of the outdoor fan 26 so as to maintain a high degree of superheat.

  Here, the measurement results of the temperature sensor 28 and the pressure sensor 29 are sent to the control unit 50, and the control unit 50 can maintain the necessary degree of superheat and suppress the temperature rise of the refrigerant (circulating through the drive circuit). It is desirable to set the number of rotations of the outdoor fan 26.

Other configurations and operational effects are the same as those of the first embodiment of FIG.
In FIG. 3, the second oil separator 22 and the circuit Ls13 can be omitted as in the second embodiment of FIG.

Next, a fourth embodiment will be described with reference to FIGS. 4 and 5.
The fourth embodiment of FIGS. 4 and 5 is an embodiment for preventing the temperature of the refrigerant circulating in the drive circuit from rising, as in the third embodiment of FIG.

In FIG. 4, a drive circuit outdoor heat exchanger 27 and an outdoor fan 26 for cooling the refrigerant circulating in the drive circuit are provided on the low pressure side (suction side line Ls8) of the drive compressor 21.
A temperature sensor 28 and a pressure sensor 29 are provided on the outlet side of the outdoor heat exchanger 27 in order to control the rotational speed of the outdoor fan 26 so as to maintain an appropriate degree of superheat of the refrigerant at the suction port of the driving compressor 21. It has been.

  That is, in the fourth embodiment of FIG. 4, the refrigerant vapor circulating in the driving circuit is prevented from being overheated by cooling the refrigerant at the suction port of the driving compressor 21.

  As points to be noted when the outdoor heat exchanger 27 of the drive circuit is cooled by the outdoor fan 26, the suction pressure of the drive compressor 21 and the outlet temperature of the outdoor heat exchanger 27 are measured by sensors (a pressure sensor 29 interposed in the line Ls8 and Monitoring by the temperature sensor 28) and maintaining the outlet temperature of the outdoor heat exchanger 27 to exceed the saturation temperature of the suction pressure of the driving compressor 21 may prevent the refrigerant from condensing in the outdoor heat exchanger 27. desirable. This is because, when condensed, liquid refrigerant is mixed into the driving compressor 21 and the driving compressor 21 may be damaged by liquid compression.

  Here, the measurement results of the temperature sensor 28 and the pressure sensor 29 are sent to the control unit 50, and the control unit 50 can maintain the necessary degree of superheat and suppress the temperature rise of the refrigerant (circulating through the drive circuit). It is desirable to set the number of rotations of the outdoor fan 26.

In FIG. 4, the driving outdoor heat exchanger 27 and the outdoor fan 26 are arranged in a region on the driving compressor 21 side (the suction side) of the second pressure reducing valve Vx2. However, as in the modification of the fourth embodiment shown in FIG. 5, it may be provided in the region upstream of the second pressure reducing valve Vx <b> 2 (the discharge side of the driving compressor 21).
However, also in the modified example of FIG. 5, the positions of the temperature sensor 28 and the pressure sensor 29 are provided on the downstream side (drive compressor 21 side) of the second pressure reducing valve Vx2, and the cooled refrigerant vapor is supplied to the drive compressor 21. It is preferable to eliminate the possibility of condensation at the inlet.

Other configurations and operational effects are the same as those of the first embodiment of FIG.
In FIG. 3, the second oil separator 22 and the circuit Ls13 can be omitted as in the second embodiment of FIG.

  Next, a fifth embodiment will be described with reference to FIGS. In the fifth embodiment shown in FIGS. 6 and 7, a part of the liquid refrigerant is heated and evaporated by bringing the discharge gas of the driving compressor 21 into contact with the liquid refrigerant in the refrigerant tank, while the refrigerant vapor is To be cooled. This is an embodiment for preventing overheating of the refrigerant vapor.

In FIG. 6, the front end of the line Ls4 in FIG. Through the refrigerant).
When the refrigerant vapor moves between the liquid refrigerant in the tank T1 (in the form of bubbles), the refrigerant vapor on the drive circuit side comes into gas-liquid contact with the liquid refrigerant on the main circuit side, and the drive circuit side refrigerant vapor is retained. Sensible heat is put into the main circuit side liquid refrigerant. As a result, the refrigerant vapor on the drive circuit side is cooled. By doing so, overheating of the refrigerant vapor on the drive circuit side can be prevented.

  As described above, it is desirable that the refrigerant vapor discharged from the line Ls4 is discharged from the lower portion of the tank T1. This is because the refrigerant vapor naturally rises due to the mass difference, and heat exchange proceeds by contact with the liquid refrigerant in the tank T1 and stirring.

The modification of the fifth embodiment in FIG. 7 is an example in which the tip of the line Ls4 in FIG. 1 is bent in a folded bowl shape and penetrated upward from the bottom of the refrigerant tank T1.
Other configurations and operational effects in the fifth embodiment of FIGS. 6 and 7 are the same as those of the first embodiment of FIG.

  Next, a sixth embodiment will be described with reference to FIG.

1 to 7, the high-pressure refrigerant vapor discharged from the driving compressor 21 contains a small amount of lubricating oil. On the other hand, since all the refrigerant evaporates in the indoor unit heat exchanger 32, the lubricating oil mixed in the refrigerant flows together with the refrigerant vapor from the outlet of the indoor heat exchanger 32 to the first low-pressure refrigerant tank 16. Accordingly, the lubricating oil stays in the first low-pressure refrigerant tank 16.
When the main compressor 11 is driven, the lubricating oil stagnated in the first low-pressure refrigerant tank 16 returns to the main compressor 11 again by the main circuit in the heat source unit 1.
However, there is a possibility that the lubricating oil mixed in the refrigerant circulating in the drive circuit moves to the main circuit side via the refrigerant tanks T1 and T2. The lubricating oil that has once gone to the main circuit side does not return to the driving compressor 21 again. As a result, the drive compressor 21 may cause a problem of running out of lubricating oil.
The sixth embodiment in FIG. 8 is an embodiment for solving such a problem.

In FIG. 8, the bottom of the first low-pressure refrigerant tank 16 is connected to a junction Gs4 provided on a line Ls13 of the drive circuit by a line Lm11 with a second bypass valve Vb2.
Since the pressure of the first low-pressure refrigerant tank 16 is higher than the suction pressure of the driving compressor 21, the lubricating oil staying in the first low-pressure refrigerant tank 16 is driven by the line Lm11 due to the pressure difference. It can be returned to.

  If the state in which the drive circuit side compressor 21 is deficient in lubricating oil (so-called “lubricated oil” state) is detected by detection means (not shown), the valve Vb2 is opened. If the valve Vb2 is opened, the lubricating oil accumulated in the first low-pressure refrigerant tank 16 moves to the second junction Gs2 via the line Lm11 and the fourth junction GS4, and the drive circuit compressor 21 Return to.

In this state (in the state of refrigerant vapor in which the lubricating oil is drifting in droplets), the droplet of lubricating oil falls when entering the first low-pressure refrigerant tank 16.
Note that lubricating oil can also accumulate in the second oil separator 22 of the drive circuit 2. In that case, it is returned to the driving compressor 21 via the line Ls13, the fourth junction point Gs4, and the second junction point Gs2.

  In FIG. 8, the second oil separator 22 and the circuit Ls13 can be omitted (as in the second embodiment of FIG. 2).

  Whether or not the compressor has become deficient in lubricating oil (so-called “lubricated oil” state) is detected by a known technique.

  Other configurations and operational effects in the sixth embodiment of FIG. 8 are the same as those of the embodiments of FIGS.

Next, a seventh embodiment will be described with reference to FIG.
Similarly to FIG. 8 (sixth embodiment), the seventh embodiment of FIG. 9 is also a technique for returning the lubricating oil to the drive circuit side compressor.

In the sixth embodiment of FIG. 8, the lubricating oil in the refrigerant circulating on the main circuit side is applied when it can be collected by the first low-pressure refrigerant tank 16, but the seventh embodiment of FIG. This is a technique that assumes a case where the lubricating oil in the refrigerant circulating through the main circuit cannot be sufficiently collected by the first low-pressure refrigerant tank 16.
For example, when liquid refrigerant accumulates in the outdoor heat exchanger 14 of the heat source unit 1 and the indoor heat exchanger 32 of the indoor unit 3, or when liquid refrigerant accumulates in the first low-pressure refrigerant tank 16 (the lubricating oil is liquid The lubricating oil cannot be sufficiently returned from the first low-pressure refrigerant tank 16 to the driving compressor 21.
The seventh embodiment of FIG. 9 reliably returns the lubricating oil to the driving compressor 21 even when the lubricating oil in the refrigerant circulating in the main circuit cannot be sufficiently collected by the first low-pressure refrigerant tank 16. It is an embodiment configured to be able to.

  In FIG. 9, the second low-pressure refrigerant tank 23 connected to the suction port of the drive compressor 21 by the line Ls9 and the oil separator 12 connected to the discharge port of the main compressor 11 are connected to the on-off valve Vb2. Is connected by a line Lm12. The middle of the line Lm12 branches at a fourth branch point Bm4, and the branch point Bm4 and the line Lm2 on the outlet side of the first oil separator 12 are connected by a line Lm13 having an on-off valve Vb3 interposed therebetween.

  Specifically, in FIG. 9, the second bypass line Lb <b> 2 on the heat source unit 1 side (the line that bypasses the main compressor from the first low-pressure refrigerant tank 16 and reaches the first oil separator 12) is third. Branch point Bm3 is provided. On the other hand, a fourth junction point Gs4 is provided in the region between the junction point Gs2 and the resistor 25 of the line Ls13 that communicates with the line Ls9 on the drive circuit side at the second junction point Gs2, and the fourth junction point is provided. The point Gs4 and the third branch point Bm3 are connected by the line Lm12 having an on-off valve Vb2.

A fourth branch point Bm4 is provided in a region of the line Ls12 between the third branch point Bm3 and the on-off valve Vb2. The line Lm2 is provided with a fifth branch point Bm5, and the fifth branch point Bm5 and the fourth branch point Bm4 are connected by the line Lm13 having an on-off valve Vb3 interposed therebetween.
In order to make the circulation amount of the lubricating oil appropriate, resistors 18 and 19 such as capillary tubes are indicated upstream or downstream of the on-off valve Vb2 in the line Lm12 (reference numeral 18 is upstream and reference numeral 19 is downstream). ) Is desirable. In order to supply lubricating oil to the driving compressor 21, the connection destination of the on-off valve Vb2 is the suction port of the driving compressor 21, the second low-pressure refrigerant tank 23, the second pressure reducing valve (expansion valve). ) It may be any downstream of Vx2.

Here, in the illustrated example, the driving compressor 21 is equipped with an oil level sensor S for detecting the oil level of the lubricating oil. The oil level detection means may be provided in the second oil separator 22.
If it is detected that the amount of lubricating oil in the driving compressor 21 is insufficient, the main compressor 11 is driven to accumulate the lubricating oil in the first oil separator 12, and the accumulated lubricating oil is collected. It is configured to return (supply) the suction side of the drive compressor 21.

  Specifically, as a method of returning the lubricating oil from the main circuit on the heat source unit 1 side to the drive circuit side, first, when the oil level sensor S detects an oil level shortage, the main compressor 11 is operated. When the main compressor 11 is operated, all of the circulating refrigerant passes through the main compressor 11 and the first oil separator 12, so that most of the lubricating oil is transferred to the main compressor 11 and the first oil separator 12. Can be captured.

Thereafter, the main compressor 11 is operated for a certain period of time, or it is confirmed that a predetermined amount of oil level is secured in the first oil separator 12 by an oil level detection mechanism of the oil separator 12 (not shown). If so, it is determined that the lubricating oil has been stored in the first oil separator 12.
As described above, the on-off valve Vb2 is opened after a lapse of a certain time or after the device is in a certain state. Lubricating oil stored in the first oil separator 12 due to the pressure difference between the discharge port of the main compressor 11 and the suction port of the drive compressor 21 passes through the on-off valve Vb2 and the suction port of the drive compressor 21. To be released.

After a certain period of time has elapsed, or after it has been confirmed by the detection means that a certain amount of oil has been stored in the driving compressor 21 or the second oil separator 22, the on-off valve Vb2 is closed. If the main compressor 11 is operated, the pressure at the discharge port of the main compressor 11 becomes sufficiently high. Therefore, the driving compressor 21 may be stopped while the main compressor 11 is operating.
When the driving compressor 21 is in operation, it is desirable that the on-off valves V1 to V4 continue the indirect outside air cooling operation.
Alternatively, all the on-off valves are opened, and the refrigerant vapor is driven by the compressor 21 → V2 and the fourth on-off valve V4 → the first refrigerant tank T1 and the second refrigerant tank T2 → the first on-off valve V1. The third on-off valve V3 → second pressure reducing valve Vx2 → second low-pressure refrigerant tank 23 → drive compressor 21 may flow. In this case, the discharge pressure of the driving compressor 21 is approximately the same as that of the main compressor 11.

  Finally, the main compressor 11 is stopped, only the driving compressor 21 is operated, and the indirect outside air cooling operation can be performed again.

In the above operation, the lubricating oil finally remains in the lubricating oil pipe between the outdoor heat exchanger 14 of the heat source unit 1 and the drive circuit 2, and the amount of lubricating oil becomes insufficient when the pipe length is long. Therefore, the on-off valve Vb2 is kept open, and the on-off valve Vb3 is further opened. Then, a high-pressure discharge gas (refrigerant) flows through the on-off valve Vb3, the inside of the lubricating oil pipe can be filled with refrigerant vapor, and the shortage of lubricating oil can be resolved.
The first oil separator 12 and the open / close valve Vb2 are connected so that the discharge gas coming from the open / close valve Vb3 flows through the open / close valve Vb2 instead of the lubricating oil from the first oil separator 12 when the open / close valve Vb3 is opened. It is desirable to equip a resistor 18 such as a capillary tube in the middle of the lines Lb2 and Lm12.
Needless to say, while the main compressor 11 is operating to store the lubricating oil in the oil separator 12, the main circuit can form a compression refrigeration cycle and can continue indoor cooling.

  In FIG. 9, the second oil separator 22 and the line Ls13 on the drive circuit 2 side can be omitted as in the second embodiment of FIG.

  Other configurations and operational effects in the seventh embodiment of FIG. 9 are the same as those of the embodiments of FIGS.

Next, an eighth embodiment will be described with reference to FIGS.
According to 5th Embodiment of FIG.6 and FIG.7, the refrigerant temperature which flows through a drive circuit can be dropped.
However, as a result of the vapor-liquid contact between the refrigerant vapor circulating in the drive circuit and the liquid refrigerant circulating in the main circuit in one or both of the refrigerant tanks T1, T2, the liquid refrigerant circulating in the main circuit evaporates. As a result, the amount of refrigerant vapor flowing into the drive circuit and flowing through the drive circuit increases. As a result, the pressure in one of the refrigerant tanks T1 and T2 increases, and there is a possibility that the liquid refrigerant circulating in the main circuit may not be sucked. Alternatively, if the operation is continued further due to an increase in the refrigerant vapor flowing through the drive circuit, the discharge pressure of the drive compressor 21 is abnormally increased and adversely affects the devices of the drive circuit.

  The countermeasures for preventing the refrigerant amount from increasing on the drive circuit side and preventing the empty tank of one of the refrigerant tanks T1 and T2 from sucking the liquid refrigerant are shown in FIGS. 12 is an eighth embodiment.

In FIG. 10, a pressure sensor Sp is interposed in the line Ls <b> 1 on the discharge side of the driving compressor 21. The pressure sensor is connected to the control unit 50 through the input signal line Si.
The first to fourth on-off valves V1 to V4 and the on-off valves (bypass valves) Vb2 and Vb3 are connected to the control unit 50 through a control signal line So.

  When the pressure sensor Sp interposed in the drive circuit detects an increase in the discharge pressure of the drive compressor, the control unit 50 closes the on-off valves V1 and V3 connected to the suction port of the drive compressor 21, In addition, one or both of the on-off valves V2 and V4 connected to the discharge port of the driving compressor 21 are opened, and the refrigerant purge operation is continued until a predetermined state is reached.

  The mode of continuing the refrigerant purge operation is not limited to the above-described one. For example, when the pressure sensor Sp detects an increase in the discharge pressure of the drive compressor, the discharge port of the drive compressor 21 is completely or almost closed while the second pressure reducing valve (expansion valve) Vx2 is closed. The refrigerant purge operation can be performed by opening one or both of the on-off valves V2 and V4 connected to the.

  Further, an opening / closing valve (bypass valve) Vb4 is added to the line Ls13 of the discharge port of the driving compressor 21, and the line Ls13 and the line (circulation oil piping) Lm12 are connected at the junction Gs4. The on-off valve Vb4 is connected to the control unit 50 through a control signal line So.

  In the eighth embodiment configured as described above, when the pressure of the drive circuit increases, there are two methods for decreasing the pressure. That is, one is a method of flowing refrigerant from the check valve (Vc2 and / or Vc4) side of the drive circuit to the indoor unit 3 side, and two is refrigerant from the line Lm12 (lubricating pipe) to the main circuit. This is a method of inflow. Hereinafter, a method for reducing the pressure will be described in detail with reference to FIGS.

  10 and 11, first, the indirect outside air cooling operation is started (step S1). In step S2, the control unit 50 constantly monitors the pressure value of the pressure sensor Sp, and determines whether or not the discharge pressure of the driving compressor 21 has become a predetermined value or more. If it is not less than the predetermined value (YES in step S2), the process proceeds to step S3. If it is less than the predetermined value (NO in step S2), the loop in step S2 is repeated.

In step S3, the control unit 50 closes the on-off valves V1, V2, and V3 and opens the on-off valve V4. Then, the suction pressure of the drive compressor 21 decreases (step S4).
The refrigerant that has passed through the on-off valve V4 flows into the main circuit side via the refrigerant tank T2, the line Ls17, the fourth branch point Bs4, the line Ls19, the fourth check valve Vc4, the line Ls24, and the connection point J2. (Step S5).

  Then, the discharge pressure of the driving compressor 21 decreases (step S6). In the next step S7, the control unit 50 determines whether or not the discharge pressure of the driving compressor 21 has become a predetermined value or less.

  If the discharge pressure of the driving compressor 50 becomes a predetermined value or less (YES in Step S7), the process returns to Step S1, and Steps S1 and after are repeated again. On the other hand, if the discharge pressure of the drive compressor 50 still exceeds the predetermined value (NO in step S7), the process returns to step S2, and step S2 and subsequent steps are repeated.

  As another method, in FIG. 10 and FIG. 12, first, the indirect outside air cooling operation is started (step S11). In step S12, the control unit 50 constantly monitors the pressure value of the pressure sensor Sp, and determines whether or not the discharge pressure of the drive compressor 21 has become a predetermined value or more. If it is equal to or greater than the predetermined value (YES in step S12), the process proceeds to step S13. If it is less than the predetermined value (NO in step S12), the loop in step S2 is repeated.

  In step S13, the control unit 50 opens the on-off valves (bypass valves) Vb2, Vb3, Vb4. Then, the refrigerant vapor in the drive circuit is opened / closed (bypass valve) Vb4, junction point Gs4, line Lm12, on / off valve (bypass valve) Vb2, branch point Bm4, line Lm13, on / off valve (bypass valve) Vb3, or branched. It flows out to the main circuit via the point Bm4 and the line Lb2 (step S14).

  In the next step S15, the control unit 50 determines whether or not the discharge pressure of the driving compressor 50 has become a predetermined value or less.

  If the discharge pressure of the driving compressor 21 is equal to or lower than the predetermined value (YES in step S15), the process returns to step S11, and step S11 and subsequent steps are repeated again. On the other hand, if the discharge pressure of the driving compressor 50 still exceeds the predetermined value (NO in step S15), the process returns to step S12, and step S12 and subsequent steps are repeated.

  As an alternative method, if the refrigerant pressure on the drive circuit side exceeds a predetermined value, the on-off valves V1 to S4 are opened and the second pressure reducing valve (expansion valve) Vx2 on the low pressure side is closed. good. As a result, the refrigerant vapor circulating in the drive circuit flows to the main circuit side, and the cooling of the indoor unit 3 is temporarily stopped (the refrigerant vapor of the drive circuit flows through the indoor heat exchanger of the main circuit, thereby cooling the room Can't)

  As another method, when the discharge pressure of the driving compressor 21 increases, the on-off valves (bypass valves) Vb4 and Vb2 are opened to purge the refrigerant vapor to the main circuit side. Therefore, the refrigerant vapor circulating in the drive circuit is released to the main circuit side, thereby suppressing an increase in the refrigerant pressure circulating in the drive circuit. The purged refrigerant vapor flows into the main circuit by passing through the resistor 18.

  In FIG. 10, an oil separator and a line that communicates the bottom of the oil separator with the suction port side of the drive compressor 21 may be provided on the drive circuit side.

  As described above, according to the eighth embodiment shown in FIGS. 10 to 12, since the means (purge means) for supplying the refrigerant vapor circulating in the drive circuit to the main circuit side is provided, the increased refrigerant vapor is mainly used. By purging to the circuit side, it is possible to keep the filling amount of the refrigerant vapor circulating in the drive circuit constant and to prevent the entire drive circuit from being boosted.

  It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.

The block diagram which shows 1st Embodiment. The block diagram which shows 2nd Embodiment. The block diagram which shows 3rd Embodiment. The block diagram which shows 4th Embodiment. The block diagram which shows the modification of 4th Embodiment. The principal part sectional view showing an example of a 5th embodiment. The principal part sectional drawing which shows the modification of 5th Embodiment. The block diagram which shows 6th Embodiment. The block diagram which shows 7th Embodiment. The block diagram which shows the structure of 8th Embodiment. The flowchart which shows an example of control of 8th Embodiment. The flowchart which shows the modification of control of 8th Embodiment. The block diagram which shows the structure of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heat source machine 2 ... Drive circuit 3 ... Indoor unit 11 ... Main compressor 12 ... 1st oil separator 13 ... Outdoor fan 14 ... Outdoor heat exchanger 15 ... High-pressure refrigerant tank 16 ... first low-pressure refrigerant tank 17 ... resistor 21 ... driving compressor 22 ... second oil separator 23 ... second low-pressure refrigerant tank 24, 25 ... resistor 31 ... indoor fan 32 ... indoor heat exchanger Bm1-Bm5 ... branch point Bs1-Bs4 on main circuit side ... branch point Gm1 on drive circuit side ... Junction points Gs1 to Gs4 on the main circuit side ... Junction points Si on the drive circuit side ... Input signal line So ... Control signal line Sp ... Pressure sensors V1 to V4 ... On-off valves Vb, Vb1, Vb2 ... Open / close valve (bypass valve)
Vc1 to Vc4 ... check valves Vx1, Vx2 ... pressure reducing valves (expansion valves)
T1, T2 ... Refrigerant tank

Claims (6)

  The main circuit includes a main circuit, a drive circuit, the main circuit includes a main compressor, an outdoor heat exchanger, a decompression unit, and an indoor heat exchanger, and the refrigerant vapor flows through the drive circuit. A refrigerant tank that stores refrigerant that circulates through the main circuit in communication with the main circuit, and a driving compressor that supplies refrigerant vapor to the refrigerant tank, and communicates with the suction side of the driving compressor. An air conditioning system in which liquid refrigerant circulating through the main circuit is sucked into the refrigerant tank and liquid refrigerant accumulated in the refrigerant tank communicating with the discharge side of the driving compressor is pushed out to the main circuit. apparatus.   Circuit switching means is interposed in the drive circuit, and the communication between the suction side and the discharge side of the drive compressor and the refrigerant tank is such that when the refrigerant tank is empty or the refrigerant tank is filled with liquid refrigerant, The air conditioner according to claim 1, wherein the air conditioner is configured to be switched by a circuit switching means.   The air conditioner according to claim 1, wherein the driving circuit is provided with a cooling means for cooling the refrigerant vapor.   4. A circuit in which a low-pressure refrigerant tank is interposed in a region between the indoor heat exchanger of the main circuit and the main compressor, and a circuit that communicates the low-pressure refrigerant tank and the suction side of the driving compressor is provided. The air conditioner according to any one of the above.   The air conditioning system according to any one of claims 1 to 4, wherein a lubricating oil catching means is provided on the discharge side of the main compressor, and a circuit is provided for communicating the lubricating oil catching means with the suction side of the driving compressor in the drive circuit. apparatus.   The air conditioner according to any one of claims 3 to 5, further comprising means for supplying refrigerant vapor circulating in the drive circuit to the main circuit side.

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