JP2005321145A - Refrigerant transporting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerant transporting device capable of circulating a refrigerant without using a mechanical means such as a displacement type pump and preventing its structure from being too complicated. <P>SOLUTION: This refrigerant transporting device is mounted in a main circuit C1 communicating a heat source machine 1 and a thermal load for circulating the refrigerant, and comprises a compressor 21, a pair of refrigerant tanks T1, T2 communicated with the main circuit C1 and storing the refrigerant circulated in the main circuit C1, and a driving circuit C2 communicated with the compressor 21 and the refrigerant tanks T1, T2 for circulating refrigerant vapor. The liquid refrigerant circulated in the main circuit C1 is sucked to the refrigerant tank (for example, T1) communicated with a suction side of the compressor 21, and the liquid refrigerant stored in the refrigerant tank (for example, T2) communicated with a discharge side of the compressor 21 is pressed out to a main circuit C1 side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air conditioner, and more particularly, to a refrigerant transfer device that can suitably transfer a refrigerant (volatile medium: refrigerant) that is a medium that moves cold and hot heat.

In absorption refrigerators and compression refrigerators, there is a so-called “water pipe” in which cold / hot water is used as a medium (refrigerant or heat medium) for supplying cold or warm heat to the room.
However, “water piping” using cold / hot water has a problem of “leakage”, so it is avoided in offices that handle OA equipment. On the other hand, the construction cost is also high.

  In order to solve such a problem, there has been proposed a method (compression type refrigerator) in which a volatile medium (refrigerant) is circulated in a room, the medium is cooled or heated by a heat source device, and driven (circulated) by a refrigerant pump. (For example, refer to Patent Document 1).

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 with 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, a head must be given to the refrigerant by the pump.
On the other hand, the refrigerant has poor lubricity, and the material of the component parts such as gears wears, so 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 refrigerant by a temperature difference generated by heat and the 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 circulates a refrigerant (secondary refrigerant that conveys cold or warm heat) without using mechanical means such as a positive displacement pump. It is an object of the present invention to provide a refrigerant transfer device that can be used and that the structure does not become too complicated.

  The refrigerant transfer device of the present invention communicates a heat source device (1) and a thermal load (cooling load or heating load: indoor heat exchanger 32, indoor fan 31) and conveys the refrigerant (cooling or heating). A pair of volatile refrigerants, for example, chlorofluorocarbons, interposed in the main circuit (C1) that circulates in the compressor (21) and the refrigerant that communicates with the main circuit (C1) and circulates through the main circuit (C1). The refrigerant tanks (T1, T2), the compressor (21) and the refrigerant tanks (T1, T2) communicate with each other, and a drive circuit (C2) is provided in which refrigerant vapor (secondary refrigerant in a gas phase) circulates. The liquid refrigerant circulating in the main circuit (C1) (secondary refrigerant in the liquid phase) is sucked into the refrigerant tank (for example, T1) communicated with the suction side of the compressor (21) and the compressor (21). Liquid coolant accumulated in a refrigerant tank (for example, T2) communicating with the discharge side of It is configured as extruded to the main circuit (C1) side (claim 1).

  Here, circuit switching means (for example, on-off valves V1 to V4) are interposed in the drive circuit (C2), and the suction side and discharge side of the compressor (21), the refrigerant tanks (T1, T2), When the refrigerant tank (T1, T2) is empty or the refrigerant tank (T1, T2) is filled with liquid refrigerant (when liquid refrigerant is full), the circuit switching means (For example, by switching the open / close state of the open / close valves V1 to V4, it is possible to switch which of the refrigerant tanks T1 and T2 communicates between the suction side and the discharge side of the compressor 21). (Claim 2: FIG. 1).

  In the present invention, the drive circuit (C2) includes a cooling means for cooling the refrigerant vapor circulating through the drive circuit (C2) (for example, the heat exchanger 26 and the cooling fan 27 or shown in FIGS. 5 and 6). It is preferable that a structure for allowing the refrigerant vapor to pass through the liquid refrigerant stored in at least one of the refrigerant tanks T1 and T2 is provided (Claim 3: FIGS. 2 to 6).

  In the present invention, a low-pressure refrigerant tank (16) (which stores low-pressure refrigerant vapor) is interposed in the main circuit (C1), and the compressor in the low-pressure refrigerant tank (16) (bottom thereof) and the drive circuit (C2) It is preferable to provide a circuit (line Lb, resistor 17) that communicates with the suction side of (21) (Claim 4: FIG. 7).

In addition, in the present invention, it is preferable to provide means (purge means) for supplying the refrigerant vapor circulating in the drive circuit (C2) to the main circuit (C1) side (Claim 5: FIGS. 8 to 11). .
Specifically, the circuit switching means (for example, the on-off valves V1 to V4) for switching the communication between the refrigerant tanks (T1, T2) and the discharge side or the suction side of the compressor (21) is switched to switch the drive circuit (C2). The refrigerant vapor circulating through the refrigerant is supplied to the main circuit (C1) via the (at least one) refrigerant tank (from the main circuit C1 to the main circuit C1 via V4, T2, and CV4). Forming a circuit to be used) (FIGS. 8 and 9).
Alternatively, a circuit (circuits Lb2, V11, and 26) that connects the discharge side of the compressor (21) in the drive circuit (C2) to the main circuit (C1) may be provided (FIGS. 10 and 11).

According to the refrigerant transport device (2: claims 1 and 2) of the present invention having the above-described configuration, the main circuit (C1) is circulated through the refrigerant tank (for example, T1) communicated with the suction side of the compressor (21). Liquid refrigerant to be sucked and liquid refrigerant accumulated in a refrigerant tank (for example, T2) communicating with the discharge side of the compressor (CP21) is sent out to the main circuit (C1) side.
Therefore, the refrigerant reliably circulates in the main circuit (C1), and the cold or warm heat supplied to the refrigerant in the heat source unit (1) is reliably conveyed to the thermal load (indoor side: 3).

  The refrigerant flowing through the drive circuit (C2) of the refrigerant transfer device (2) is refrigerant vapor, and its mass flow rate is 1/20 or less compared to liquid refrigerant. Therefore, the circulating flow rate (mass flow rate) of the refrigerant in the drive circuit (C2) of the refrigerant transfer device (2) is much smaller than the circulating flow rate of the refrigerant in the main circuit (C1). As a result, less energy is required to drive the compressor (21), which meets the demand for energy saving.

  Further, mechanical movement means such as a gear pump in the prior art becomes unnecessary, and there is no problem of wear unless the compressor 21 is depleted of lubricating oil. Furthermore, it does not become too complicated mechanically, and therefore the frequency of occurrence of failures is low.

The refrigerant vapor circulating in the drive circuit (C2) is compressed by the compressor (21) and presses the liquid refrigerant in the refrigerant tanks (T1, T2), and then is sucked into the compressor (21) and compressed again. The energy obtained by being compressed is not dissipated anywhere. Therefore, the refrigerant vapor circulating in the drive circuit (C2) may be overheated.
On the other hand, if the driving circuit (C2) is provided with a cooling means for cooling the refrigerant vapor circulating in the circuit (driving circuit C2) (Claim 3), the risk of the refrigerant overheating is obviated. Can be prevented.

Here, the lubricating oil mixed in the refrigerant circulating in the drive circuit (C2) may move to the main circuit (C1) side via the refrigerant tanks (T1, T2), but the main circuit (C1). Since the lubricating oil applied to the side does not return to the drive circuit (C2) again, the 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) (which stores low-pressure refrigerant vapor) is interposed in the main circuit (C1), and the low-pressure refrigerant tank (16) (the bottom thereof) and a drive circuit (C2 ), A circuit (line Lb, resistor 17) communicating with the suction side of the compressor (21) is provided (Claim 4), and the lubricating oil mixed in the refrigerant circulating in the main circuit (C1) side Since it is captured by the low-pressure refrigerant tank (16), the lubricating oil is compressed by the circuit (Lb) that connects the captured refrigerant to the suction side of the compressor (21) in the main circuit (C1) and the drive circuit (C2). Return to the suction side of the machine (21). As a result, running out of lubricating oil in the compressor is prevented in advance.

When the refrigerant tanks (T1, T2) communicate with the 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 means (purge means) for supplying the refrigerant vapor circulating through the drive circuit (C2) to the main circuit (C1) side is provided (Claim 5), the increased refrigerant vapor (circulates through the drive circuit C2). By purging the refrigerant vapor to the main circuit (C1) side, the charging amount of the refrigerant vapor circulating in the drive circuit (C2) is kept constant, and the entire drive circuit (C2) is prevented 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 refrigerant transfer device is denoted by reference numeral 2, and is connected to a line forming the main circuit C1 at connection points J1 and J2.
The main circuit C1 connects the refrigerant transfer device 2, the heat source unit (for example, an absorption chiller / hot water unit that uses water as a refrigerant) 1 and the indoor unit 3 in a circuit form, and transfers hot or cold heat in the main circuit (C1). The secondary refrigerant is circulated.
In order to simplify the expression, in this specification, the secondary refrigerant is simply referred to as “refrigerant”. Similarly, in the present specification, a secondary refrigerant in a gas phase state is expressed as “refrigerant vapor”, and a secondary refrigerant in a liquid phase state is expressed as “liquid refrigerant”.

  The indoor unit 3 includes an indoor fan 31, an indoor heat exchanger (evaporator) 32, and a first pressure reducing valve (expansion valve) Vx1.

  The main circuit C1 is connected to the first pressure reducing valve (expansion valve) via the line Lm1, the first connection point J1 and the second connection point J2 on the refrigerant transfer device 2 side in order from the discharge side of the outdoor unit 1. ) The line Lm2 interposing Vx1, the indoor heat exchanger 32 of the indoor unit 3, the line Lm3, and the suction side of the outdoor unit 1 are each connected in a circuit shape.

The refrigerant transfer device 2 includes a compressor 21, an oil separator 22, first to fourth on-off valves V1 to V4, first and second refrigerant tanks T1 and T2, and first to fourth reverses. In addition to having stop valves Vc1 to Vc4, a pressure reducing valve Vx2, and a low pressure refrigerant tank 23, these devices are connected and configured by respective lines forming a drive circuit C2 described below.
The refrigerant transport device 2 is interposed in the main circuit C1 and forms a circuit in which the refrigerant of the air conditioner circulates together with the main circuit C1.

  A line Ls1 is connected to the discharge side of the compressor 21, and the line Ls1 branches into a line Ls2 and a line Ls11 at a first branch point Bs1, and the line Ls2 is connected to the inflow side of the oil separator 22. . A line Ls3 is connected to the discharge side of the oil separator 22, and the line Ls3 is provided at the second branch point Bs2 with the line Ls4 interposed with the second on-off valve V2 and the second on-off valve V4. 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 merge at the first merge point Gs1 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 low pressure refrigerant tank 23.

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

  The first branch point Bs1 and the second junction point Gs2 are connected by the line Ls11 having a resistor 24 interposed therebetween, and the bottom of the oil separator 22 and the low-pressure refrigerant tank 23 are connected via a resistor 25. The line Ls12 is connected. The line Ls12 is a circuit for preventing the lubricant from running out of the compressor 21 by returning the lubricant accumulated in the oil separator 22 to the compressor 21.

The resistor 25 alleviates shocking pressure fluctuations that occur when the on-off valves V1 to V4 are switched, and protects the piping and devices of the entire drive circuit C2 from accidents such as damage.
For 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 C1 side by a line Ls21, and the close side of the second check valve Vc2 is connected to the main circuit C1 side by a line Ls22. Are connected to the second connection point J2.
The open side of the third check valve Vc3 is connected to a first connection point J1 with the main circuit C1 side by a line Ls23, and the close side of the fourth check valve Vc4 is connected to the main circuit by a line Ls24. It is connected to the second connection point J2 with the C1 side.

  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 principle of refrigerant conveyance in the drive circuit C2 in the refrigerant conveyance device 2 and the flow of refrigerant in the main circuit (refrigerant circuit having the heat source unit 1 and the indoor unit 3) C1 at that time will be described below.

The operation during normal cooling with a high outside air temperature will be described with reference to FIG.
First, on-off valves V1 and V4 are opened, and V2 and V3 are closed. The refrigerant flowing through the main circuit C1 is cooled and liquefied by the heat source unit 1.

The compressor 21 includes a line Ls6 provided with an on-off valve V1, a first junction GS1, a line LS8 via a second pressure reducing valve Vx2, a low-pressure refrigerant tank 23, a line Ls9, a second junction Gs2, and a line. The refrigerant vapor in the refrigerant tank T1 is sucked through Ls10. Since the on-off valve V2 is closed at that time, the refrigerant tank T1 is decompressed.
The decompressed refrigerant tank T1 sucks the liquid refrigerant flowing through the main circuit C1.

  On the other hand, the compressor 21 discharges refrigerant vapor from the discharge side, and a line Ls5 including a line Ls1, a line Ls2, an oil separator 22, a line Ls3, a second branch point Bs2, and a fourth on-off valve V4. Then, the refrigerant vapor is sent out to the refrigerant tank T2. As described above, since the on-off valve V3 is closed at this time, 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 changed to a line Ls19 that includes a line LS17, a fourth branch point Bs4, and a fourth check valve Vc4. It flows into the line Lm2 on the main circuit C1 side via the line Ls24 and the second connection point J2. The refrigerant flowing into the line Lm2 is depressurized and expanded by the first pressure reducing valve (expansion valve) Vx1, and is sent to the indoor heat exchanger 32 of the indoor unit 2.

  In the indoor heat exchanger 32, the indoor air is cooled by the heat of vaporization when the refrigerant evaporates, and is returned to the compressor 21 via the line Lm3.

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.
This causes the liquid refrigerant in the first refrigerant tank T1 to be sent out to the indoor heat exchanger 32 (main circuit C1 side), and the second refrigerant tank T2 sucks the liquid refrigerant flowing through the main circuit C1.

  By repeating the above cycle, the refrigerant circulates between the heat source unit 1 and the indoor heat exchanger 32.

  According to the refrigerant transfer device 2 of the first embodiment described above, cold heat from the heat source unit 1 is applied to the refrigerant (volatile refrigerant, for example, chlorofluorocarbon) circulating in the main circuit C1, and the refrigerant into which the cold heat is input is used as the main circuit C1. Then, it is conveyed to the indoor heat exchanger 32, and the cold heat held by the refrigerant can be input to the indoor heat exchanger 32.

  Since the refrigerant flows through the indoor heat exchanger 32, it is not necessary to flow cold water (water in which cold heat is input by the absorption chiller / heater 1) to the indoor heat exchanger 32. Therefore, it is not necessary to use water piping that is avoided in the OA equipment system.

  In order to press the liquid refrigerant circulating in the main circuit C1 from the refrigerant tank (T1 or T2) to the main circuit C1 side, the same volume of refrigerant vapor (a drive circuit C2 which is a circulation circuit in the refrigerant transfer device 2) What is necessary is just to press (liquid refrigerant in a tank) with the refrigerant | coolant vapor | steam which circulates inside.

Here, if the volume is the same, the mass of the refrigerant vapor can be 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 compressor is 1.443 MPa (saturation temperature, equivalent to 20 ° C.), and the temperature is 50 ° C. (at the compressor outlet). Therefore, when the refrigerant vapor presses the liquid refrigerant in a saturated state at the same pressure as the refrigerant vapor (refrigerant vapor discharged from the compressor), the density of the refrigerant vapor is 46. whereas a .14kg / ^{m 3,} the density of the liquid refrigerant 1085kg / ^{m 3,} and the density ratio is 20 times or more.
As a result, the mass flow rate circulated by the compressor 21 can be less than 1/20 that of the liquid refrigerant. That is, it meets the demand for energy saving.

  Further, in the embodiment of FIG. 1, mechanical movement means such as a gear pump is unnecessary as is clear from FIG. 1, and there is no problem of wear that is indispensable when the mechanical movement means is used. . Furthermore, it is not too complicated mechanically.

Next, a second embodiment will be described with reference to FIG.
In the first embodiment of FIG. 1 described above, the refrigerant vapor circulating through the drive circuit C2 on the refrigerant conveyance device 2 side is “compressed and pressed against the liquid refrigerant in the refrigerant tank (T1 or T2), and compressed for driving. Although it is sucked into the machine 21 and compressed again, the energy obtained by the compression is not dissipated anywhere. As a result, the temperature immediately rises.
In other words, the refrigerant vapor in the drive circuit C2 on the refrigerant conveyance device 2 side is constantly sucked into the compressor 21 and is repeatedly discharged, so that the temperature immediately rises. As a result, there is a problem that the refrigerant vapor circulating through the drive circuit C2 immediately rises to a dangerous temperature range.
The second embodiment shown in FIG. 2 solves this problem.

In FIG. 2, an outdoor heat exchanger 26 having an outdoor fan 27 is interposed in the refrigerant line Ls3 (a line connecting the oil separator 22 and the open / close valves V1 to V4). That is, the refrigerant vapor having the highest temperature discharged from the compressor 21 is cooled by the outdoor heat exchanger 26 and the outdoor fan 27 for the drive circuit C2. In this way, the temperature of the refrigerant circulating in the drive circuit, that is, the circuit C2 on the refrigerant conveyance device 2 side, is prevented.
In other words, in the second embodiment of FIG. 2, overheating of the refrigerant gas circulating through the compressor 21 can be prevented by cooling the refrigerant at the discharge port of the compressor 21.

  As a point to be noted when the outdoor heat exchanger 27 of the drive circuit C2 is cooled by the outdoor fan 26, the discharge pressure of the compressor 21 and the outlet temperature of the outdoor heat exchanger 26 are measured with sensors (the temperature sensor 28 and the pressure interposed in the line Ls3). It is desirable to prevent the refrigerant from being liquefied in the outdoor heat exchanger 26 by monitoring with the sensor 29) and maintaining the outlet temperature of the outdoor heat exchanger 26 to exceed the saturation temperature of the discharge pressure of the driving compressor 21. .

  That is, if the refrigerant vapor circulating through the drive circuit C2 is liquefied, there is an advantage that “the mass flow rate of the refrigerant vapor is 1/20 or less of the mass flow rate of the liquid refrigerant, so that energy for driving the compressor can be saved”. It will disappear. Therefore, the outdoor fan 27 is controlled so that the refrigerant temperature at the outlet of the outdoor heat exchanger 26 of the drive circuit C2 becomes higher than the refrigerant condensation temperature, and the cooled refrigerant vapor is maintained in a gas phase state without condensing. That is, it is necessary to control the rotation speed of the outdoor fan 27 so as to maintain an appropriate degree of superheat.

Here, the measurement result of the temperature sensor 28 and / or the pressure sensor 29 is sent to the control unit 50, and the control unit 50 maintains the necessary degree of superheat and suppresses the temperature rise of the refrigerant (circulating through the drive circuit). It is desirable to set the rotation speed of the outdoor fan 26 as much as possible.
Other configurations and operational effects are the same as those of the first embodiment of FIG.

Next, a third embodiment will be described with reference to FIGS. 3 and 4.
The third embodiment of FIGS. 3 and 4 is an embodiment for preventing the temperature of the refrigerant circulating in the circulation circuit (drive circuit) C2 in the refrigerant transfer device 2 from increasing, as in the second embodiment of FIG. It is.

In FIG. 3, an outdoor heat exchanger 26 and an outdoor fan 27 for cooling the refrigerant circulating in the drive circuit C2 are provided on the line Ls8 on the suction side of the compressor 21.
A temperature sensor 28 and / or a pressure sensor 29 is provided on the outlet side of the outdoor heat exchanger 27 in order to control the rotational speed of the outdoor fan 27 so as to maintain an appropriate degree of superheat of the refrigerant vapor on the suction side of the compressor 21. It has been.
That is, in the third embodiment of FIG. 3, the refrigerant gas circulating in the drive circuit C2 can be prevented from being overheated by cooling the refrigerant vapor at the suction port of the compressor 21.

  As a point to keep in mind when the outdoor heat exchanger 26 of the drive circuit C2 is cooled by the outdoor fan 27, the suction pressure of the compressor 21 and the outlet temperature of the outdoor heat exchanger 26 are measured using the sensors (the pressure sensor 29 and the temperature interposed in the line Ls8). It is desirable to prevent the refrigerant from being liquefied in the outdoor heat exchanger 26 by monitoring with the sensor 28) and maintaining the outlet temperature of the outdoor heat exchanger 26 to exceed the saturation temperature of the suction pressure of the compressor 21. This is because when liquefied, the refrigerant liquid is mixed into the compressor 21 and the driving compressor 21 may be damaged by the liquid compression.

  Here, the measurement result of the temperature sensor 28 and / or the pressure sensor 29 is sent to the control unit 50, and the control unit 50 maintains the necessary degree of superheat and increases the temperature of the refrigerant (circulating through the drive circuit C2). It is desirable to set the rotation speed of the outdoor fan 27 to such an extent that it can be suppressed.

In FIG. 3, the outdoor heat exchanger 26 and the outdoor fan 27 are disposed in a region between the second pressure reducing valve Vx <b> 2 and the compressor 21. However, as in a modification of the fourth embodiment shown in FIG. 4, it may be provided in a region upstream of the second pressure reducing valve Vx2 (discharge side of the compressor 21).
However, also in the modified example of FIG. 4, the positions of the temperature sensor 28 and the pressure sensor 29 are provided on the downstream side (compressor 21 side) of the second pressure reducing valve Vx2, and the liquid refrigerant can be sucked through the suction port of the compressor 21. It is preferable to wipe off the property.

Other configurations and operational effects are the same as those of the first embodiment of FIG.
3 and 4, the oil separator 22 and the circuit Ls12 can be omitted as in the second embodiment of FIG.

Next, a fourth embodiment will be described with reference to FIGS.
In the fourth embodiment shown in FIGS. 5 and 6, by bringing the discharge gas of the compressor 21 into contact with the refrigerant liquid in the refrigerant tank (T1, T1), a part of the refrigerant liquid is superheated and evaporated, The refrigerant gas is cooled. This is an embodiment for preventing overheating of the refrigerant gas.

In FIG. 5, the front end of the line Ls4 in FIG. 1 is passed through to the vicinity of the bottom of the first refrigerant tank T1, and the refrigerant vapor circulating through the drive circuit C2 from the front end of the line Ls4 is supplied to the liquid refrigerant (main circuit C1) 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 C2 side comes into gas-liquid contact with the liquid refrigerant on the main circuit C1 side, and the refrigerant vapor on the drive circuit C2 side Is stored in the main circuit C1-side refrigerant. As a result, the refrigerant vapor on the drive circuit C2 side is cooled. By doing so, overheating of the refrigerant on the drive circuit C2 side can be prevented.
As described above, the refrigerant gas discharged from the line Ls4 is preferably discharged from the lower portion of the tank T1. This is because the refrigerant gas naturally rises due to the mass difference, and the heat exchange proceeds by contact with the refrigerant liquid in the tank T1 and stirring.

The modification of the fourth embodiment in FIG. 6 is an example in which the tip of the line Ls4 in FIG. 1 is bent into a folded bowl shape and penetrated upward from the bottom of the refrigerant tank T1.
Other configurations and operational effects in the fourth embodiment shown in FIGS. 5 and 6 are the same as those in the first embodiment shown in FIG.

Next, a fifth embodiment will be described with reference to FIG.
In each embodiment of FIGS. 1-6, although it is trace amount, lubricating oil mixes in the high pressure refrigerant | coolant vapor | steam discharged from the compressor 21 and circulating through the 2nd circulation circuit C2 in the refrigerant | coolant conveyance apparatus 2. FIG. There is a possibility that the lubricating oil mixed in the refrigerant circulating in the drive circuit C2 moves to the main circuit C1 side that is the main circuit via the refrigerant tanks T1 and T2. The lubricating oil that has once gone to the main circuit C1 side does not return to the compressor 21 on the second circulation circuit C2 side in the refrigerant transfer device 2 again. As a result, the compressor 21 may cause a problem of running out of lubricating oil.
The fifth embodiment in FIG. 7 is an embodiment for solving such a problem.

  In FIG. 7, a low-pressure refrigerant tank 16 is interposed in a line Lm3 on the main circuit C1 side where the refrigerant circulates. The bottom of the low-pressure refrigerant tank 16 is connected to a junction Gs3 provided on a line Ls8 of the drive circuit by a line Lb with a resistor 17 interposed.

  With such a configuration, when the compressor 21 is operated and the refrigerant flows through the main circuit C <b> 1 in which the refrigerant circulates, the lubricating oil mixed in the refrigerant is accumulated in the low-pressure refrigerant tank 16. On the other hand, since the pressure of the low-pressure refrigerant tank 16 is higher than the suction pressure of the driving compressor 21, the lubricating oil staying in the low-pressure refrigerant tank 16 can be returned to the compressor 21 side by the pressure difference by the line Lb.

  The reason why the lubricating oil accumulates in the low-pressure refrigerant tank 16 is that the refrigerant and the lubricating oil are compatible. When the refrigerant is in the liquid phase, the lubricating oil dissolves in the liquid refrigerant. On the other hand, when the refrigerant is in the gas phase, the lubricating oil becomes droplets and floats in the refrigerant vapor. Then, when the lubricating oil drifting in the refrigerant vapor of the main circuit C1 flows into the low-temperature refrigerant tank 16, the lubricating oil droplet falls to the bottom of the tank 16 and accumulates.

The return line Lb of the lubricating oil only needs to secure a pressure difference enough for the lubricating oil to flow, and is connected to any of the low pressure tank 23, the compressor 21 suction port, and the second pressure reducing valve (expansion valve) Vx2. desirable.
Further, the lubricating oil also accumulates in the oil separator 22, and in that case, the lubricating oil is returned to the compressor 21 via the line Ls12.

  Other configurations and operational effects in the fifth embodiment of FIG. 7 are the same as those of the embodiments of FIGS.

Next, a sixth embodiment will be described with reference to FIGS.
According to 4th Embodiment of FIG.5 and FIG.6, the temperature of the refrigerant | coolant which flows through the circulation circuit (drive circuit) C2 in the refrigerant | coolant conveyance apparatus 2 can be dropped.
However, as a result of the gas-liquid contact between the refrigerant vapor circulating in the drive circuit C2 and the liquid refrigerant circulating in the main circuit C1 on the indoor heat exchanger 3 side in one or both of the tanks T1 and T2, the main circuit C1. The liquid refrigerant circulating through evaporates and flows into the drive circuit C2. As a result, the amount of refrigerant vapor flowing through the drive circuit C2 increases. As a result, the pressure in one of the tanks T1 and T2 increases, and the liquid refrigerant circulating in the main circuit C1 may not be sucked.

  The amount of refrigerant is prevented from increasing on the side of the drive circuit C2, which is a circulation circuit in the cooling and conveying apparatus 2, and the situation where one of the tanks T1 and T2 does not suck liquid refrigerant is prevented. A countermeasure for this is the fifth embodiment.

  In FIG. 8, a pressure sensor Sp is interposed in the line Ls1 on the discharge side of the compressor 21. The pressure sensor is connected to the control unit 50 through an input signal line Si. On the other hand, the first to fourth on-off valves V1 to V4 are connected to the control unit 50 by a control signal line So.

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

  However, the mode of continuing the refrigerant purge operation is not limited to the above. For example, when the pressure sensor Sp detects an increase in the discharge pressure of the compressor 21, the refrigerant purge operation can be continued if the second pressure reducing valve (expansion valve) Vx2 is completely or almost closed. .

  In the sixth embodiment configured as described above, a method for lowering the increased pressure when the pressure of the drive circuit C2, which is the circulation circuit in the refrigerant transfer device 2, has increased excessively will also be described with reference to FIGS. Will be described in detail.

  8 and 9, first, the indirect outside air cooling operation is started (step S1). In step S2, the control unit 50 starts open / close control of the open / close valves V1 to V4 in order to switch the refrigerant tanks T1 and T2 between high pressure and low pressure.

  In the next step S3, 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 equal to or greater than the predetermined value (YES in step S3), the process proceeds to step S4. If it is less than the predetermined value (NO in step S3), the loop of steps S2 to S3 is repeated.

In step S4, the control unit 50 closes the on-off valves V1, V2, and V3 and opens the on-off valve V4. Then, since the on-off valves V1 and V3 are closed, the suction pressure of the compressor 21 decreases (step S5).
On the other hand, the refrigerant that has passed through the on-off valve V4 passes through 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 in the main circuit. Open to a certain main circuit C1 side (step S6).

  Then, the discharge pressure of the compressor 21 decreases (step S7). In the next step S8, the control unit 50 determines whether or not the discharge pressure of the compressor 21 has become a predetermined value or less.

  If the discharge pressure of the compressor 21 is equal to or lower than the predetermined value (YES in step S8), the process returns to step S1, and step S1 and subsequent steps are repeated again. On the other hand, if the discharge pressure of the compressor 21 still exceeds the predetermined value (NO in step S8), the process returns to step S2, and step S2 and subsequent steps are repeated.

  In addition, when the refrigerant | coolant vapor | steam which circulates through the drive circuit C2 in the refrigerant | coolant conveyance apparatus 2 flows into the main circuit C1 side, and reaches | attains the indoor unit 3, the cooling of the indoor unit 3 will be in a temporary stop state. This is because the refrigerant vapor of the drive circuit C2 has already vaporized when flowing through the indoor heat exchanger 32 of the main circuit C1, and thus the heat exchanger 32 does not take away the heat of evaporation.

  Next, a seventh embodiment will be described with reference to FIGS. 10 and 11. Similarly to the sixth embodiment of FIGS. 8 and 9, the seventh embodiment of FIGS. 10 and 11 also prevents the amount of refrigerant in the main circuit C1, which is the main circuit, from increasing. This is an embodiment for preventing a situation in which one empty tank does not suck liquid refrigerant.

  In FIG. 10, a branch point Bm is provided in the line Lm3 of the main circuit C1, which is the main circuit, a branch point Bs5 is formed in the line Ls3 of the drive circuit C2 on the refrigerant transfer device 2 side, and the branch point Bm and the branch point Bs5 communicates with the line Lb2.

  The line Lb2 is provided with a resistor 26 and an opening / closing valve V11 in order of flow from the main circuit C1 side, and the opening / closing valve V11 is connected to the control unit 50 by a control signal line So. In the drive circuit C2, a pressure sensor Ps is interposed in the discharge side line Ls1 of the compressor 21, and the pressure sensor Ps is connected to the control unit 50 by an output signal line Si.

  According to the seventh embodiment configured as described above, when the pressure on the discharge side of the compressor 21 rises by a predetermined value or more, the on-off valve V11 is opened and the refrigerant vapor is supplied to the main circuit C1 side which is the main circuit. Purge. Accordingly, the refrigerant vapor circulating in the drive circuit C2 which is a circulation circuit in the refrigerant transfer device 2 is released to the main circuit C1 side, and the increase in the refrigerant pressure circulating in the drive circuit C2 is suppressed. The purged refrigerant vapor flows into the heat source unit 1 and is immediately condensed. Then, it circulates in the main circuit C1, which is the main circuit.

  Here, when the on-off valve V11 is opened, the vapor refrigerant is suddenly charged from the drive circuit C2 side to the main circuit C1 side, and if the pressure fluctuation at that time is too large, a sudden load fluctuation occurs in the compressor 21. I will let you. The resistor 26 is provided to prevent such a rapid pressure fluctuation.

  In the seventh embodiment having the above-described configuration, FIG. 11 shows a method for reducing the pressure (vapor refrigerant purging method) when the pressure of the drive circuit C2, which is a circulation circuit in the refrigerant transfer device 2, has increased excessively. This will be described in detail with reference to FIG.

  First, indirect outside air cooling operation is started (step S11). In step S12, the control unit 50 closes the on-off valve V11. In the next step S13, the control unit 50 constantly monitors the pressure value of the pressure sensor Sp, and determines whether or not the discharge pressure of the compressor 21 has become a predetermined value or more. If it is equal to or greater than the predetermined value (YES in step S13), the process proceeds to step S14. If it is less than the predetermined value (NO in step S13), the loop of steps S12 to S13 is repeated.

  In step S14, the control unit 50 opens the on-off valve V11. Then, the refrigerant vapor in the drive circuit (circulation circuit in the refrigerant transfer device 2) C2 flows out to the main circuit C1 via the on-off valve (bypass valve) V11 and the resistor 26 of the line Lb2 (step S15).

  In the next step S16, the control unit 50 determines whether or not the discharge pressure of the compressor 21 has become a predetermined value or less.

  If the discharge pressure of the compressor 21 is equal to or lower than the predetermined value (YES in step S16), 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 compressor 21 still exceeds the predetermined value (NO in step S16), the process returns to step S12, and step S12 and subsequent steps are repeated.

  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 8th Embodiment. The block diagram which shows the structure of 9th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heat source machine 2 ... Refrigerant conveyance apparatus 3 ... Indoor unit 21 ... Compressor 22 ... Oil separator 24, 25 ... Resistor 31 ... Indoor fan 32 ... Indoor heat exchangers Bs1 to Bs4 ... branch points Gs1 to Gs3 on the drive circuit side ... confluence points on the drive circuit side ... input signal line So ... control signal line Sp ... pressure sensors V1 to V1 V4 ... Open / close valve Vb, Vb2 ... Open / close valve (bypass valve)
Vc1 to Vc4 ... check valves Vx1, Vx2 ... pressure reducing valves (expansion valves)
T1, T2 ... Refrigerant tank

Claims (5)

  A compressor, a pair of refrigerant tanks that store refrigerant that circulates through the main circuit in communication with the main circuit, and that is interposed in a main circuit that communicates the heat source device and the thermal load and circulates the refrigerant, and the compressor Is connected to the refrigerant tank and the refrigerant vapor is circulated, and the liquid refrigerant circulating in the main circuit is sucked into the refrigerant tank communicated with the suction side of the compressor and communicated with the discharge side of the compressor. A refrigerant conveying apparatus, wherein the liquid refrigerant accumulated in the refrigerant tank is pushed out to the main circuit side.   Circuit switching means is interposed in the drive circuit, and the communication between the suction side and the discharge side of the compressor and the refrigerant tank is such that the refrigerant tank is empty or the refrigerant tank is filled with liquid refrigerant. The refrigerant transfer device according to claim 1, wherein the refrigerant transfer device is configured to be switched by a circuit switching means.   The refrigerant transfer device according to claim 1, wherein the driving circuit is provided with a cooling means for cooling the refrigerant vapor circulating through the driving circuit.   The refrigerant conveyance device according to any one of claims 1 to 3, wherein a low-pressure refrigerant tank is interposed in the main circuit, and a circuit that communicates the low-pressure refrigerant tank and the suction side of the compressor in the drive circuit is provided.   The refrigerant conveyance device according to any one of claims 1 to 4, wherein means for supplying refrigerant vapor circulating through the drive circuit to the main circuit side.

Images