JP2001235242A - Freezer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a configuration of a freezer device using a so-called thermal driving pump and reduce its cost, and assure a circulation of a refrigerant at a secondary circuit irrespective of any operating condition. SOLUTION: At a secondary circuit (20), a secondary side refrigerant is circulated between a major heat exchanger (HEX2) and an indoor heat exchanger (HEX1). A primary side circuit (10) is connected to the major heat exchanger (HEX2). The primary side circuit (10) performs a freezing cycle operation to apply cold heat to the secondary side refrigerant. When pressures in main tanks (T1, T2) are reduced, solenoid valves for pressure reduction (SV-P1, SV-P2) are opened to make the main tanks (T1, T2) communicate with the major heat exchanger (HEX2). Accordingly, the major heat exchanger (HEX2) also performs a function to absorb the gaseous refrigerant contained in the main tanks (T1, T2) and condense it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a refrigeration apparatus,
In particular, the present invention relates to a refrigeration apparatus that circulates a refrigerant and conveys and uses cold heat from a heat source to a use side.

[0002]

2. Description of the Related Art Hitherto, as a refrigerating apparatus, a refrigerating apparatus having a closed circuit in which a refrigerant circulates, giving cold heat of a cold heat source to the circulating refrigerant and conveying the refrigerant to a use side has been known. For example, Japanese Patent Application Laid-Open No. H11-281174 discloses a refrigerating apparatus of this type applied to an air conditioner.

The refrigerating apparatus disclosed in the above publication has a primary circuit and a secondary circuit in which the refrigerant circulates. In the primary circuit, the refrigerant circulates to perform a vapor compression refrigeration cycle. The primary refrigerant of the primary circuit absorbs heat from the secondary refrigerant of the secondary circuit in the main heat exchanger and evaporates,
The secondary refrigerant in the secondary circuit radiates heat to the primary refrigerant in the primary circuit in the main heat exchanger and condenses. That is, in the main heat exchanger, cold heat of the primary circuit is given to the secondary refrigerant.

[0004] The secondary side circuit conveys the cold heat provided by the main heat exchanger to the indoor heat exchanger on the utilization side by circulation of the secondary side refrigerant. Specifically, the secondary refrigerant condensed in the main heat exchanger is sent to the indoor heat exchanger. For indoor heat exchangers, 2
The secondary refrigerant absorbs heat from the object and evaporates, thereby cooling the object. The evaporated secondary refrigerant is sent to the main heat exchanger and condensed again, and repeats this circulation.

[0005] At this time, in the secondary circuit of the refrigeration system,
The refrigerant is circulated by a so-called heat drive pump.
Specifically, a pair of tanks for storing the liquid refrigerant, a cooling heat exchanger, and a heating heat exchanger are provided. The cooling heat exchanger condenses the gas refrigerant and is maintained at a low pressure, and sucks the gas refrigerant in the tank. The tank is depressurized by the suction of the gas refrigerant. On the other hand, the heating heat exchanger evaporates the refrigerant and is maintained at a high pressure, and supplies a high-pressure gas refrigerant into the tank. The tank is pressurized by the supply of the gas refrigerant.

In the secondary circuit, one of the tanks is pressurized to push out the liquid refrigerant, and at the same time, the other tank is depressurized to collect the liquid refrigerant. Is given. Further, the tank for pressurizing and the tank for depressurizing are alternately switched to continuously circulate the secondary refrigerant.

[0007]

However, in the above-mentioned refrigerating apparatus, in addition to the main heat exchanger on the heat source side and the indoor heat exchanger on the use side, heat exchange for circulating the refrigerant in the secondary circuit is performed. Vessel is required. For this reason, there has been a problem that the number of heat exchangers constituting the apparatus is increased, the configuration is complicated, and the cost is increased.

Further, if liquid refrigerant accumulates in a heat exchanger (cooling heat exchanger) for sucking gas refrigerant and depressurizing the tank, the amount of refrigerant condensed in the cooling heat exchanger cannot be secured, and There has been a problem that a sufficient circulation driving force cannot be given to the refrigerant in the side circuit.

That is, in a normal operation state, only the gas refrigerant is sucked from the tank. However, for example, when the operation state suddenly changes, suction may be continued even though the tank is filled with the liquid refrigerant, and the liquid refrigerant may be erroneously drawn into the cooling heat exchanger. Further, when the refrigerant amount in the secondary circuit is excessive with respect to the operation state,
The liquid refrigerant easily accumulates in the cooling heat exchanger. When the liquid refrigerant accumulates in the cooling heat exchanger, the effective heat transfer area contributing to heat exchange decreases, and the amount of refrigerant condensed in the cooling heat exchanger decreases. For this reason, the cooling heat exchanger cannot be maintained at a sufficiently low pressure, and the pressure in the tank may be insufficiently reduced.

[0010] In order to solve the above-mentioned problem, measures to increase the size of the cooling heat exchanger can be considered. However, the use of a heat exchanger larger than the capacity required under normal operating conditions is contrary to the demand for miniaturization and cost reduction.

The present invention has been made in view of the above points, and an object of the present invention is to reduce the cost by simplifying the structure of a refrigeration apparatus using a so-called heat-driven pump. An object of the present invention is to ensure circulation of a refrigerant in a heat transfer circuit regardless of an operation state.

[0012]

Means for Solving the Problems A first solution taken by the present invention is a cold heat source (10) for generating cold heat, a main heat exchanger (HEX2), a refrigerant transfer means (30) and a use side. A heat exchanger (HEX1) is connected to the pipe, and a main heat exchanger (HEX2) is connected to a cold heat source (10) to apply cold heat to the transfer refrigerant and circulate the transfer refrigerant to use the cold heat as heat on the user side. Exchanger (HE
X1) is a refrigeration apparatus provided with a heat transfer circuit (20) for transfer to the refrigeration apparatus. The transfer means (30) is connected to the heat transfer circuit (20) and stores a pair of tanks (T1, T2) for storing the transfer refrigerant, and stores the evaporated refrigerant in the tank (T1, T1).
T2) and a high-pressure section (HEX3) for pressurizing the tanks (T1, T2) and the main heat exchanger (HEX).
2) is configured to condense the gas refrigerant sucked from the tanks (T1, T2) to transfer the cold to the transfer refrigerant and to depressurize the tanks (T1, T2) during the transfer of the cold heat. , The transfer means (30) is provided in one tank (T1)
At the same time as pushing out the transfer refrigerant from the tank (T1), and depressurizing the other tank (T2) to reduce the tank (T2).
Then, an operation of recovering the transfer refrigerant is performed to apply a circulation driving force to the transfer refrigerant.

According to a second aspect of the present invention, in the first aspect of the present invention, the non-azeotropic mixed refrigerant is used as a refrigerant for transport in the heat transport circuit (20).

According to a third aspect of the present invention, there is provided the above-described first or second aspect, further comprising a heat source (10) for applying heat to the transfer refrigerant of the heat transfer circuit (20). The heat transfer circuit (20) switches between cold transfer and hot transfer by circulating a transfer refrigerant, while the transfer means (30)
Is equipped with a cooling heat exchanger (HEX4) for condensing the gas refrigerant sucked from the tanks (T1, T2) during the transfer of hot heat.

According to a fourth aspect of the present invention, in the third aspect, the cooling heat exchanger (HEX4) condenses the gas refrigerant sucked from the tanks (T1, T2) during the transfer of the hot heat. At the same time, in order to maintain the transfer refrigerant collected in the tanks (T1, T2) in the liquid phase, the transfer refrigerant sent from the use-side heat exchanger (HEX1) to the tanks (T1, T2) is cooled. Then, a supercooled state is established.

In the first solution, the heat transfer circuit (20) connects the main heat exchanger (HEX2), the refrigerant transfer means (30), and the use side heat exchanger (HEX1) by piping. It is composed. The heat transfer circuit (20) is filled with a transfer refrigerant, and the transfer refrigerant circulates through the heat transfer circuit (20). The cold heat source (10) applies cold heat to the transfer refrigerant in the main heat exchanger (HEX2). That is, in the main heat exchanger (HEX2), the cold heat source (10) absorbs heat from the transfer refrigerant, and the transfer refrigerant radiates heat and condenses. The condensed refrigerant in the liquid phase is condensed into a liquid phase, is provided with a circulating driving force by the conveying means (30), is decompressed by the expansion mechanism (EV), and is then introduced into the use side heat exchanger (HEX1).

In this solution, the transport means (30) is constituted by a so-called heat-driven pump instead of a general mechanical pump. Specifically, a pair of tanks (T1, T
2) is installed, and each tank (T1, T2) is connected to the heat transfer circuit (20). The transport means (30) is provided with a high-pressure section (HEX3) and a low-pressure section. The high pressure section (HEX3) is maintained at a high pressure by evaporating the liquid refrigerant. On the other hand, the low pressure part
Low pressure is maintained by condensing the gaseous refrigerant.
In the present solution, the main heat exchanger (HEX2) functions as a low-pressure section. This will be described later.

In the transfer means (30), one tank (T1) is communicated with the high-pressure section (HEX3), and the high-pressure section (HEX3) is introduced with a high-pressure gas refrigerant to pressurize the tank (T1). At the same time, the other tank (T2) communicates with the low pressure section,
The tank (T2) is depressurized by sucking the gas refrigerant into the low pressure section.
Then, the transfer refrigerant stored in one tank (T1) is pushed out to the heat transfer circuit (20), and the heat transfer circuit (2
The transfer refrigerant from 0) is collected in the other tank (T2).

Subsequently, on the contrary, one of the tanks (T
1) is communicated with the low pressure part to reduce the pressure, and at the same time, the other tank (T2) is communicated with the high pressure part (HEX3) and pressurized. Thereby, the transfer refrigerant collected in the other tank (T2) is again pushed out to the heat transfer circuit (20), and the transfer refrigerant is collected from the heat transfer circuit (20) in the one tank (T1). . The transfer means (30) applies a circulating driving force to the transfer refrigerant of the heat transfer circuit (20) by performing the above operations alternately.

According to the present invention, when the cold heat is transferred,
The main heat exchanger (HEX2) of the heat transfer circuit (20) doubles as the low pressure section of the transfer means (30). As described above, in the main heat exchanger (HEX2), the transfer refrigerant is condensed by the cold heat of the cold heat source (10). Therefore, during the transfer of cold heat, the main heat exchanger (HEX2) is maintained at a low pressure by condensation of the gas refrigerant. Therefore, the tank (T1, T2) is communicated with the main heat exchanger (HEX2), and the gas refrigerant in the tank (T1, T2) is sucked into the main heat exchanger (HEX2) to be condensed. Reduce the pressure of T1, T2).

In the second solution, the heat transfer circuit (2
A non-azeotropic mixed refrigerant is used as the transfer refrigerant in 0). The non-azeotropic mixed refrigerant is obtained by mixing a plurality of refrigerants having different boiling points at a predetermined composition ratio.
C corresponds to this. R407C is R32, R1
25 and R134a, the composition ratio of which is R32: 23 (wt%) / R125: 25 (wt%) / R1
34a: 52 (wt%).

In the third solution, a heat source (10) for generating heat is provided, and a heat transfer circuit (20) switches between transfer of cold heat and transfer of warm heat. When transferring warm heat,
The transfer refrigerant evaporates in response to the heat of the heat source (10), and the gas refrigerant generated by the evaporation is introduced into the use-side heat exchanger (HEX1). In the use side heat exchanger (HEX1), the gas refrigerant radiates heat and condenses, and the condensed heat heats the object. The condensed transfer refrigerant receives the heat of the heat source (10) again, evaporates, and repeats this circulation.

When transferring warm heat, a cooling heat exchanger (HEX4)
Constitutes the low-pressure section of the transfer means (30). This cooling heat exchanger (HEX4) is maintained at a low pressure by condensation of the gas refrigerant. And the tank (T1, T2) and the cooling heat exchanger (HEX4)
And the gas refrigerant in the tanks (T1, T2) is sucked into the cooling heat exchanger (HEX4) to be condensed, thereby reducing the pressure in the tanks (T1, T2). That is, at the time of transferring heat, the cooling heat exchanger (HEX4) functions as a low-pressure part of the transfer means (30), and the main heat exchanger (HEX2) does not function as a low-pressure part.

In the fourth solution, the cooling heat exchanger (HEX4) performs two functions during the transfer of hot heat.
That is, the cooling heat exchanger (HEX4) functions as a low-pressure portion of the transport means (30) for condensing the gas refrigerant sucked from the tanks (T1, T2), and at the same time, uses the use-side heat exchanger (HEX4).
An operation is performed in which the transport refrigerant condensed in 1) and collected in the tanks (T1, T2) is cooled to a supercooled state.

Here, the transfer refrigerant condensed in the use-side heat exchanger (HEX1) is almost saturated, so the tank (TEX)
There is a risk of flashing when collected at 1, T2).
For this reason, at the time of transfer of warm heat, a means (liquid phase maintaining means) for cooling the transfer refrigerant collected in the tanks (T1, T2) and maintaining it in the liquid phase may be provided. Therefore, in this solution, the cooling heat exchanger (HEX4) is returned to Europe as the liquid phase maintaining means.

More specifically, as described above, the cooling heat exchanger (HEX4) cools and condenses the gas refrigerant. Therefore, the transfer refrigerant condensed in the use-side heat exchanger (HEX1)
Before being collected in the tanks (T1, T2), the cooling heat exchanger (HEX
Introduce to 4). In the cooling heat exchanger (HEX4), the transfer refrigerant from the use-side heat exchanger (HEX1) is cooled and brought into a supercooled state. Therefore, the tank (T1, T
The transfer refrigerant recovered in 2) is always maintained in the liquid phase and does not flash.

[0027]

According to the present invention, during the transfer of cold heat, the main heat exchanger (HEX2) of the heat transfer circuit (20) is connected to the transfer means (3).
0) and also serves as a low-pressure section. That is, the main heat exchanger (HEX2), which is indispensable for applying the cold heat of the cold heat source (10) to the transfer refrigerant of the heat transfer circuit (20), is connected to the transfer means (3).
It is made to function also as a low pressure part of 0). For this reason, it is not necessary to separately provide a heat exchanger for configuring the low-pressure section of the transporting means (30), and the configuration can be simplified and the cost can be reduced.

The main heat exchanger (HEX2) is for giving cold heat to the transfer refrigerant, and is usually of a large capacity having a large amount of heat exchange. That is, the capacity of the main heat exchanger (HEX2) is larger than the capacity of the heat exchanger when the low-pressure section of the conveying means (30) is configured by a separate heat exchanger.
Is larger. Therefore, even if the liquid refrigerant accumulates in the large-capacity main heat exchanger (HEX2), if the amount of accumulated liquid refrigerant is equal, the ratio of the effective heat transfer area which is reduced by this is lower in the low-pressure section. It is smaller than when it is configured with a separate small-capacity heat exchanger.

[0029] Therefore, even when the liquid refrigerant is accumulated in the main heat exchanger (HEX2) due to a sudden change in the operation state or the like, the main heat exchanger (HEX2) can be maintained at a sufficiently low pressure. It is. As a result, regardless of driving conditions,
The amount of gas refrigerant sucked from the tanks (T1, T2) can be secured,
The tanks (T1, T2) can be sufficiently depressurized to reliably apply the circulating driving force to the transfer refrigerant.

In particular, in the second solution, a non-azeotropic refrigerant mixture is used as the refrigerant for transport in the heat transport circuit (20). Here, when the non-azeotropic refrigerant mixture evaporates, the low-boiling component having a relatively low boiling point among the components evaporates first. On the other hand, when recovering the liquid refrigerant by depressurizing the tanks (T1, T2), the gas refrigerant is sucked from the tanks (T1, T2) to the low-pressure section of the conveying means (30) to be condensed.

Therefore, when the pressure in the tanks (T1, T2) is reduced, the liquid refrigerant and the gas refrigerant coexist in the tanks (T1, T2), so that the tanks (T1, T2) are sucked. The gas refrigerant has a higher proportion of low-boiling components than the non-azeotropic mixed refrigerant having a normal composition. When the proportion of the low-boiling component in the gas refrigerant increases, the condensing temperature is lower than that of a non-azeotropic mixed refrigerant having a normal composition. For this reason, if only the gas refrigerant sucked from the tanks (T1, T2) is to be condensed, the amount of condensation decreases with a decrease in the condensing temperature of the gas refrigerant, and the pressure in the tanks (T1, T2) becomes insufficient. Become. Also,
Attempting to maintain the amount of gas refrigerant condensed causes an increase in the energy required for condensing the gas refrigerant.

On the other hand, in the present solution, the main heat exchanger (HEX2) also serves as the low-pressure section of the transfer means (30) when transferring cold heat. Therefore, the tank (T
The gas refrigerant sucked from the T1) is used as a heat exchanger (HE
It is sent to the main heat exchanger (HEX2) together with the gas refrigerant from X1) and condenses. That is, tanks (T1, T2)
The gas refrigerant having a large amount of low boiling point components sucked from the gas is mixed with the gas refrigerant having a normal composition ratio from the indoor heat exchanger (HEX1), and thereafter, is introduced into the main heat exchanger (HEX2).

Therefore, the change in the composition ratio of the gas refrigerant flowing into the main heat exchanger (HEX2) can be reduced, and the non-azeotropic mixed refrigerant having substantially the same composition as the normal composition ratio can be removed from the main heat exchanger (HEX2).
Can be sent to As a result, the main heat exchanger (HEX
The condensing temperature of the refrigerant in 2) can be kept constant, and the amount of refrigerant condensed can be ensured, and the pressure in the tanks (T1, T2) can be reliably reduced.

Further, according to the third and fourth solving means, not only the transfer of cold heat but also the transfer of warm heat can be switched. Here, at the time of transferring the heat, if the main heat exchanger (HEX2) applies heat to the transfer refrigerant, the transfer refrigerant is evaporated in the main heat exchanger (HEX2). And in this case, the main heat exchanger (HE
Since X2) has a high pressure, the main heat exchanger (HEX2) cannot function as the low-pressure section of the transport means (30). Therefore, in order to transfer the heat, it is necessary to provide a cooling heat exchanger (HEX4) that constitutes the low-pressure section during the transfer of the heat.

On the other hand, in the fourth solution, the cooling heat exchanger (HEX4) required for transferring the heat is provided by:
It is made to function also as a liquid phase maintenance means. That is, the cooling heat exchanger (HEX4) functions as both the low-pressure section of the transport means (30) and the liquid phase maintaining means. Therefore, it is possible to minimize the increase in the number of heat exchangers and to transfer the heat while minimizing the complexity of the configuration.

According to the fourth solution, when the heat is transferred, the transfer refrigerant recovered to the tanks (T1, T2) is cooled by the cooling heat exchanger (HEX4) to be in a supercooled state. And it is possible to maintain the transfer refrigerant in a liquid phase. For this reason, the transfer refrigerant flowing into the main tanks (T1, T2) can be reliably turned into a liquid phase, and the circulating driving force applied by the transfer means (30) decreases due to the flash of the refrigerant. Can be prevented. As a result, the heat transfer circuit (2
The circulation amount of the transfer refrigerant in step 0) can be ensured, and the transfer amount of warm heat can be sufficiently ensured.

[0037]

Embodiment 1 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, the refrigeration apparatus according to the present invention is configured as an air conditioner.

<< Overall Configuration of Air Conditioner >> As shown in FIG.
The air conditioner according to the first embodiment is configured as a so-called multi-type in which a plurality of indoor units (22) are connected to one outdoor unit (29). The outdoor unit (29) and each indoor unit (22) are connected by a liquid side communication pipe (27) and a gas side communication pipe (28).

The air conditioner includes a primary circuit (10),
A secondary circuit (20) is provided. In addition, a pump circuit (30) is provided in the secondary circuit (20). The primary circuit (10) and the pump circuit (30) are housed in an outdoor unit (29). On the other hand, the secondary circuit (20)
It is provided from the outdoor unit (29) to the indoor unit (22).

The primary circuit (10) is a closed circuit including a primary compressor (11) and the like, and is configured so that a refrigerant circulates to perform a vapor compression refrigeration cycle. The primary circuit (10) is also configured to perform an operation for driving the pump circuit (30). The primary circuit (10) will be described later.

<< Configuration of Secondary Side Circuit >> The secondary side circuit (2
0) constitutes a heat transfer circuit. This secondary side circuit (2
0) is a secondary four-way switching valve (23) and a cooling heat exchanger (HEX
4), an indoor expansion valve (EV), an indoor heat exchanger (HEX1) which is a use side heat exchanger, and a main heat exchanger (HEX2) are connected in order by piping. Of the secondary circuit (20)
Secondary side four-way switching valve (23), cooling heat exchanger (HEX4),
The main heat exchanger (HEX2) is housed in the outdoor unit (29). On the other hand, the indoor expansion valve (EV) and the indoor heat exchanger (HEX1) are housed one by one in a plurality of indoor units (22).

The secondary four-way switching valve (23) and the indoor expansion valve (E
A main liquid pipe (25) is provided between V), and a cooling heat exchanger (HEX4) is provided in the middle of the main liquid pipe (25). One end of the main liquid pipe (25) is a secondary four-way switching valve (23)
, And the other end is branched and connected to each indoor expansion valve (EV). In addition, a portion of the main liquid pipe (25) extending from the outdoor unit (29) to each indoor unit (22) forms a liquid-side communication pipe (27).

The indoor heat exchanger (HEX1) and the main heat exchanger (HEX1)
Between 2), a main gas pipe (24) is provided. One end of the main gas pipe (24) branches off, and each indoor heat exchanger (HE
X1), and the other end is connected to the upper end of the main heat exchanger (HEX2). In the main gas pipe (24), a portion extending from each indoor unit (22) to the outdoor unit (29) forms a gas-side communication pipe (28).

A main liquid pipe (26) is provided between the main heat exchanger (HEX2) and the secondary four-way switching valve (23). One end of the main liquid pipe (26) is connected to the lower end of the main heat exchanger (HEX2), and the other end is connected to the second port of the secondary four-way switching valve (23).

The secondary circuit (20) is filled with R407C, which is a non-azeotropic refrigerant mixture, as a secondary refrigerant. In the secondary circuit (20), the secondary refrigerant, which is a transfer refrigerant, circulates while changing phase, and transfers cold or warm heat from the main heat exchanger (HEX2) to the indoor heat exchanger (HEX1).

<< Structure of Pump Circuit >> The above pump circuit (3
0) constitutes a transfer means composed of a so-called heat driven pump. This pump circuit (30) is connected to a heating heat exchanger (HE
X3), a cooling heat exchanger (HEX4), a first main tank (T1), and a second main tank (T2). The pump circuit (30) alternately pressurizes and depressurizes the two main tanks (T1, T2) connected to the secondary circuit (20), and thereby circulates through the secondary refrigerant of the secondary circuit (20). It is configured to provide a driving force. The pump circuit (30)
Has a sub tank (ST) and a buffer tank (BT).

A liquid pipe for recovery (38) and a liquid pipe for extrusion (37) are connected to the first main tank (T1) and the second main tank (T2), respectively.

The extruding liquid pipe (37) has one end branched into three branch pipes (37a, 37b, 37c) and the other end connected to the third port of the secondary four-way switching valve (23). It is connected. The branch pipes (37a, 37b, 37c) of the extrusion liquid pipe (37) are
They are connected to the lower ends of the second main tank (T1, T2) and the sub tank (ST). Of these branch pipes (37a-37c)
Branch pipe (3) connected to the first and second main tanks (T1, T2)
7a, 37b) are provided with a check valve (CV-3) that allows only the outflow of refrigerant from the main tanks (T1, T2). The branch pipe (37c) connected to the sub tank (ST)
A check valve (CV-4) that allows only the flow of the refrigerant into the sub tank (ST) is provided.

One end of the collection liquid pipe (38) is connected to the fourth port of the secondary four-way switching valve (23), and the other end is connected to the second port.
It is branched into two branch pipes (38a, 38b). The branch pipes (38a, 38b) of the recovery liquid pipe (38) are connected to lower ends of the first and second main tanks (T1, T2). Each of the branch pipes (38a, 38b) is provided with a check valve (CV-5) that allows only refrigerant to flow into the main tanks (T1, T2).

The secondary side four-way switching valve (23) is provided with a liquid pipe for extrusion (37) and a main liquid pipe (25) on the indoor unit (22) side.
And the main heat exchanger (HEX2)
The main liquid pipe (26) on the side is in communication (the state shown by the solid line in Fig. 1), the liquid pipe for extrusion (37) and the main heat exchanger (HEX2)
The state is switched to a state in which the main liquid pipe (26) on the side communicates with the recovery liquid pipe (38) and the main liquid pipe (25) on the indoor unit (22) side (the state indicated by the broken line in FIG. 1). It is configured as follows. By switching the secondary four-way switching valve (23), the circulation direction of the secondary refrigerant in the secondary circuit (20) is switched.

The heating heat exchanger (HEX3) includes first and second heat exchangers (HEX3).
It is for pressurizing the main tank (T1, T2) and the sub tank (ST), and constitutes a high-pressure section. The heating heat exchanger (HEX3) is connected to the first and the first via a gas supply pipe (31).
It is connected to the second main tank (T1, T2) and the sub tank (ST). One end of the gas supply pipe (31) is connected to the upper end of the heating heat exchanger (HEX3), and the other end is branched into three branch pipes (31a, 31b, 31c). Gas supply pipe (31)
Branch pipes (31a to 31c) are connected to the first and second main tanks (T
1, T2), connected to the upper end of the sub tank (ST).
These branch pipes (31a to 31c) are provided with first to third tank pressurizing solenoid valves (SV-P1, SV-P2, SV-P3).

The heating heat exchanger (HEX3) is connected to the sub tank (ST) via a liquid recovery pipe (34).
One end of the liquid recovery pipe (34) is connected to the lower end of the sub tank (ST), and the other end is connected to the lower end of the heating heat exchanger (HEX3). This liquid recovery pipe (34) has a sub tank (S
Check valve (CV-1) that allows only refrigerant to flow out of T)
And a buffer tank (BT) are provided in order from the sub tank (ST) to the heating heat exchanger (HEX3).

In the heating heat exchanger (HEX3), the liquid recovery pipe (3
The liquid refrigerant supplied through 4) evaporates. The gas refrigerant of the heating heat exchanger (HEX3) passes through the gas supply pipe (31) to the first and second main tanks (T1, T2) and the sub tank (ST).
Supplied to The tank (T1, T2, ST) is pressurized by the supply of the gas refrigerant.

The buffer tank (BT) and the heat exchanger (HEX3) are connected by a pressure equalizing pipe (39).
One end of the pressure equalizing pipe (39) is connected to the upper end of the buffer tank (BT) via a liquid recovery pipe (34), and the other end is connected to a heating heat exchanger (HEX3) via a gas supply pipe (31). Is connected to the upper end.

The cooling heat exchanger (HEX4) includes first and second cooling heat exchangers (HEX4).
This is for decompressing the main tank (T1, T2) and the sub tank (ST), and constitutes a low pressure section of the pump circuit (30) during the heating operation. Further, the cooling heat exchanger (HEX4) cools the secondary refrigerant condensed by the indoor heat exchanger (HEX1) during heating to a supercooled state by exchanging heat with the primary refrigerant. In the liquid phase also serves as a liquid phase maintaining means. In the first embodiment, the main heat exchanger (HEX2) of the secondary circuit (20) forms a low-pressure section of the pump circuit (30) during the cooling operation.

The first, second and second pump circuits (30)
Third gas recovery pipes (41, 42, 43) are provided. Specifically, a first gas recovery pipe (41) is connected to the first main tank (T1), and a second gas recovery pipe (42) is connected to the second main tank (T2). Further, a third gas recovery pipe (43) is connected to the sub tank (ST).

One end of the first gas recovery pipe (41) is the first gas recovery pipe (41).
It is connected to the upper end of the main tank (T1), and the other end is branched into two branch pipes (41a, 41b). The first gas recovery pipe (41) is provided with a first tank pressure reducing solenoid valve (SV-V1). On the other hand, the second gas recovery pipe (42) has one end connected to the upper end of the second main tank (T2) and the other end branched into two branch pipes (42a, 42b). The second gas recovery pipe (42) is provided with a second tank pressure reducing solenoid valve (SV-V2).

One branch pipe (41a, 42a) of the first and second gas recovery pipes (41, 42) is connected to the main gas pipe (24) of the secondary circuit (20). Each of the branch pipes (41a, 42a) is provided with a check valve (CV-15). Each check valve (CV-15) allows only the flow of the refrigerant toward the main gas pipe (24).

The other branch pipes (41b, 42b) of the first and second gas recovery pipes (41, 42) are respectively connected to the cooling heat exchanger (HEX4) in the main liquid pipe (25) of the secondary circuit (20). ) And an indoor expansion valve (EV). Each of the branch pipes (41b, 42b) is provided with a check valve (CV-16). Each check valve (CV-16) allows only the flow of the refrigerant toward the main liquid pipe (25).

One end of the third gas recovery pipe (43) is connected to the upper end of the sub tank (ST), and the other end is branched into two branch pipes (43a, 43b). Third gas recovery pipe (43)
One of the branch pipes (43a) is connected to the main gas pipe (24) of the secondary circuit (20). The branch pipe (43a) is provided with a third tank pressure reducing solenoid valve (SV-V3) and a check valve (CV-17) in order toward the main gas pipe (24). The check valve (CV-17) allows only the flow of the refrigerant toward the main gas pipe (24). The other branch pipe (43b) of the third gas recovery pipe (43) is connected to the cooling heat exchanger (HEX4) and the indoor expansion valve (E) in the main liquid pipe (25) of the secondary circuit (20).
V). This branch pipe (43b)
A fourth tank pressure reducing solenoid valve (SV-V4) is provided.

Incidentally, the sub tank (ST) is installed at a position higher than the heating heat exchanger (HEX3). Further, the buffer tank (BT) is disposed above the heating heat exchanger (HEX3) and below the sub tank (ST).
The buffer tank (BT) is provided to supply a liquid refrigerant to the heating heat exchanger (HEX3) stably during operation and at startup.

<< Configuration of Primary Side Circuit >> The primary side circuit (1
0) constitutes both a cold heat source and a warm heat source. This one
The secondary circuit (10) includes a main circuit (15) and first to fifth branch pipes (51 to 55).

The main circuit (15) includes a primary compressor (11), a primary four-way switching valve (12), an outdoor heat exchanger (HEX).
6), a receiver (13), a heating heat exchanger (HEX3) and a main heat exchanger (HEX2) are connected by piping in order.

The main circuit (15) is provided with a check valve, a solenoid valve and the like. Specifically, the outdoor heat exchanger (HE
A check valve (CV-6) that allows only the flow of the refrigerant toward the receiver (13) is provided between the X6) and the receiver (13). A first solenoid valve (SV-1) and a check valve (CV-7) are provided between the receiver (13) and the heating heat exchanger (HEX3) in order toward the heating heat exchanger (HEX3). Have been. This check valve (CV-7) allows only the flow of the refrigerant toward the heating heat exchanger (HEX3). Between the heating heat exchanger (HEX3) and the main heat exchanger (HEX2), there is a first expansion valve (EV-1) and a check valve (CV
-8) are provided in order. This check valve (CV-8)
Only the flow of refrigerant toward the main heat exchanger (HEX2) is allowed.

One end of the first branch pipe (51) is connected to the heating heat exchanger (HEX3) in the main circuit (15) and the first expansion valve (EV).
-1), and the other end is connected between the primary four-way switching valve (12) and the suction side of the primary compressor (11) in the main circuit (15). The first branch pipe (51) has a second expansion valve (EV-2) in order from one end to the other end.
And a cooling heat exchanger (HEX4).

One end of the second branch pipe (52) is connected between the check valve (CV-8) and the main heat exchanger (HEX2) in the main circuit (15), and the other end is connected to the main circuit (15). ) Is connected between the check valve (CV-6) and the receiver (13).
The second branch pipe (52) is provided with a check valve (CV-9) that allows only the flow of the refrigerant from one end to the other end.

The third branch pipe (53) has one end connected between the first expansion valve (EV-1) and the check valve (CV-8) in the main circuit (15), and the other end connected to the main circuit. It is connected between the outdoor heat exchanger (HEX6) and the check valve (CV-6) in (15). The third branch pipe (53) is provided with a check valve (CV-10) that allows only the flow of the refrigerant from one end to the other end.

One end of the fourth branch pipe (54) is connected between the receiver (13) in the main circuit (15) and the first solenoid valve (SV-1), and the other end is connected to the main circuit (15). It is connected between the heating heat exchanger (HEX3) and the first expansion valve (EV-1). At this time, the other end of the fourth branch pipe (54) is located closer to the first expansion valve (EV-1) than one end of the first branch pipe (51) connected to the main circuit (15), and Circuit (1
5) Connected to. Further, a second solenoid valve (SV-2) is provided in the fourth branch pipe (54).

One end of the fifth branch pipe (55) is connected between the discharge side of the primary compressor (11) in the main circuit (15) and the primary four-way switching valve (12). Check valve (CV-7) and heating heat exchanger (HEX3) at the end of the main circuit (15)
Is connected between. The fifth branch pipe (55) is provided with a third solenoid valve (SV-3).

The above-mentioned primary circuit (10) is filled with R407C, which is a non-azeotropic mixed refrigerant, as the primary refrigerant. In the main circuit (15), the primary four-way switching valve (1
By the switching of 2), the circulation direction of the primary-side refrigerant, which is the heat-source-side refrigerant, is reversed, and the refrigeration cycle operation and the heat pump cycle operation are switched and performed. That is, the primary circuit (10) performs a refrigeration cycle operation when functioning as a cold heat source, and performs a heat pump cycle operation when functioning as a warm heat source.

-Operating operation- << Cooling operation >> The operating operation in the cooling operation for transferring the cooling heat generated in the primary circuit (10) to the indoor unit (22) will be described with reference to FIG.

In the primary circuit (10), the primary four-way switching valve (12) is switched as shown by the solid line in FIG. 1, and the first solenoid valve (SV-1) is opened, and the first solenoid valve (SV-1) is opened. Expansion valve (EV-
1) is adjusted to a predetermined opening. In addition, primary side circuit (10)
Then, the second expansion valve (EV-2), the second solenoid valve (SV-2), and the third solenoid valve (SV-3) are closed. When the primary-side compressor (11) is operated in this state, the primary-side circuit (10) in FIG.
The refrigeration cycle operation is performed by circulating the primary-side refrigerant as indicated by the one-dot chain line arrow.

Specifically, the primary refrigerant discharged from the primary compressor (11) flows through the primary four-way switching valve (12) to the outdoor heat exchanger (HEX6). In the outdoor heat exchanger (HEX6), the primary-side refrigerant condenses by performing heat exchange with the outside air. The condensed primary-side refrigerant flows to the heating heat exchanger (HEX3) through the receiver (13).

In the heating heat exchanger (HEX3), the primary refrigerant exchanges heat with the secondary refrigerant of the pump circuit (30). By this heat exchange, the secondary refrigerant evaporates, and the heating heat exchanger (HEX3)
Are maintained at a high pressure.

If the amount of heating of the secondary refrigerant in the heating heat exchanger (HEX3) is insufficient, the primary compressor (1
Introduce the discharge gas of 1) into the heating heat exchanger (HEX3) as appropriate. Specifically, the second solenoid valve (SV-2) and the third solenoid valve (SV-3) are opened, and the first solenoid valve (SV-1) is closed. Thereby, the discharge gas of the primary compressor (11) is introduced into the heating heat exchanger (HEX3) through the fifth branch pipe (55).
The refrigerant condensed in the heating heat exchanger (HEX3)
The refrigerant exits from 3) and merges with the refrigerant flowing through the fourth branch pipe (54).

The primary-side refrigerant from the heating heat exchanger (HEX3) flows through the main circuit (15) as it is, and the first expansion valve (EV)
After the pressure is reduced in -1), it flows into the main heat exchanger (HEX2).
In the main heat exchanger (HEX2), the primary refrigerant flows into the secondary circuit (2
Heat exchange with the secondary refrigerant of 0). By this heat exchange, 1
At the same time as the secondary refrigerant evaporates, the secondary refrigerant is condensed, and cold energy is given to the secondary refrigerant. The primary-side refrigerant evaporated in the main heat exchanger (HEX2) passes through the primary-side four-way switching valve (12) to become
It is sucked into the secondary compressor (11).

That is, in the primary circuit (10) during the cooling operation, the primary refrigerant does not flow in the first branch pipe provided with the cooling heat exchanger (HEX4).

In the secondary circuit (20), the secondary four-way switching valve (23) is switched as shown by the solid line in FIG. 1, and the indoor expansion valve (EV) is adjusted to a predetermined opening. In this state, each pressurizing solenoid valve (SV-P1, SV-P2,
SV-P3) and the respective pressure-reducing solenoid valves (SV-V1, SV-V2, SV-V3) are opened and closed to apply a circulation driving force to the secondary refrigerant. During the cooling operation, the fourth tank pressure reducing solenoid valve (SV-V4) is always closed. Then, in the secondary circuit (20), the secondary refrigerant circulates in a phase-change manner between the main heat exchanger (HEX2) and the indoor heat exchanger (HEX1), and is circulated in the primary circuit (10). The generated cold is transferred to the indoor heat exchanger (HEX1).

Specifically, the following description starts from the state where the solenoid valves (SV-P1, SV-V2, SV-P3) of the pump circuit (30) are in the following states. That is, the pressurized solenoid valve (SV-P1) of the first main tank (T1), the pressurized solenoid valve (SV-P3) of the sub tank (ST),
The pressure reducing solenoid valve (SV-V2) of the second main tank (T2) is open. On the other hand, the pressurized solenoid valve (SV-P2) of the second main tank (T2) and the depressurized solenoid valve (SV) of the first main tank (T1)
V-V1) and the pressure reducing solenoid valve (SV-V3) of the sub tank (ST) are closed.

In this state, the first main tank (T
1) communicates with the heating heat exchanger (HEX3). As described above, the heating heat exchanger (HEX3) is maintained at a high pressure due to evaporation of the refrigerant. Therefore, the first main tank (T
In 1), a high-pressure gas refrigerant of the heating heat exchanger (HEX3) is supplied through a gas supply pipe (31), and thereby the first main tank (T1) is pressurized. 1st main tank (T
When 1) is pressurized, the stored liquid refrigerant is pushed out of the first main tank (T1). 1st main tank (T
The liquid refrigerant extruded from 1) flows from the branch pipe (37a) of the extruding liquid pipe (37) to the extruding liquid pipe (37) as shown by a solid arrow in FIG. Switching valve (23)
Flows to the main liquid pipe (25) of the secondary circuit (20).

On the other hand, the second main tank (T2) is connected to the secondary circuit (2) via the branch pipe (42a) of the second gas recovery pipe (42).
0) Communicate with the main gas pipe (24). That is, the second main tank (T2) includes the branch pipe (42a) and the main gas pipe (24).
And the main heat exchanger (HEX2).

As described above, in the main heat exchanger (HEX2),
The secondary refrigerant is cooled and condensed by heat exchange with the primary refrigerant of the primary circuit (10). Therefore, the main heat exchanger (HEX2) is maintained at a low pressure. Therefore, the gas refrigerant in the second main tank (T2) is sucked into the main heat exchanger (HEX2), and the pressure in the second main tank (T2) is reduced. Second
When the pressure in the main tank (T2) is reduced, the liquid refrigerant in the secondary circuit (20) is collected in the second main tank (T2). That is, as shown by the solid line arrows in FIG. 1, the liquid refrigerant in the main liquid pipe (26) is sucked, and the secondary four-way switching valve (23), the recovery liquid pipe (38), and the recovery liquid pipe ( It flows through the branch pipe (38b) of (38) in order and is collected in the second main tank (T2).

The sub tank (ST) is in communication with the heating heat exchanger (HEX3). Therefore, the heating heat exchanger (HEX
The gas refrigerant of 3) is also supplied to the sub tank (ST), whereby the sub tank (ST) is pressurized. The liquid refrigerant is pushed out from the pressurized sub tank (ST). This liquid refrigerant is sent to the heating heat exchanger (HEX3) through the liquid recovery pipe as shown by the broken arrow in FIG. 1, and is used to maintain the heating heat exchanger (HEX3) at a high pressure. .

Thereafter, when the sub tank (ST) is almost empty, the pressurizing solenoid valve (SV-P3) of the sub tank (ST) is closed and the pressure reducing solenoid valve (SV-V3) is opened. In this state, the sub-tank (ST) is connected to the main heat exchanger (HEX2) via the branch pipe (43a) of the third gas recovery pipe (43) and the main gas pipe (24) of the secondary circuit (20). Communicate with Then, the gas refrigerant in the sub tank (ST) is sucked into the main heat exchanger (HEX2), and the pressure in the sub tank (ST) is reduced. In the depressurized sub-tank (ST), a part of the refrigerant flowing through the extruding liquid pipe (37) is collected through the branch pipe (37c).

When the sub tank (ST) is filled with the liquid refrigerant, the pressurizing solenoid valve (SV-P3) of the sub tank (ST) is opened again, the pressure reducing solenoid valve (SV-V3) is closed, and the sub tank (ST) is closed. The liquid refrigerant is sent out to the heating heat exchanger (HEX3). The above-mentioned pressurization and decompression of the sub tank (ST) is repeated, and the liquid refrigerant is continuously supplied to the heating heat exchanger (HEX3).

In the secondary circuit (20), the liquid refrigerant is pushed out from the first main tank (T1) and the liquid refrigerant is recovered into the second main tank (T2) as described above.
The secondary refrigerant circulates while changing its phase.

Specifically, the liquid refrigerant (secondary refrigerant) pushed out from the first main tank (T1) is sent to the indoor heat exchanger (HEX1) of each indoor unit (22) through the main liquid pipe (25). Is sent. The liquid refrigerant distributed to each indoor unit (22) through the liquid-side communication pipe (27) is introduced into the indoor heat exchanger (HEX1) after being decompressed by the indoor expansion valve (EV). In the indoor heat exchanger (HEX1), the depressurized secondary-side refrigerant exchanges heat with the indoor air, absorbs heat from the indoor air, and evaporates. As a result, the room air is cooled, and the low-temperature room air is supplied to the room again to perform cooling.

The refrigerant evaporated in each indoor heat exchanger (HEX1) flows through the main gas pipe (24) to the main heat exchanger (HEX2). At this time, the second main tank (T) is connected to the main gas pipe (24) through the branch pipe (42a) of the second gas recovery pipe (42).
While the gas refrigerant of 2) flows in, the third gas recovery pipe (4
The gas refrigerant in the sub tank (ST) flows through the branch pipe (43a) of 3). Therefore, the gas refrigerant from the indoor heat exchanger (HEX1) is supplied to the second main tank (T2) and the sub tank (S
It is sent to the main heat exchanger (HEX2) together with the gas refrigerant from T).

In the main heat exchanger (HEX2), the secondary refrigerant is 1
It exchanges heat with the primary refrigerant of the secondary circuit (10). By this heat exchange, the secondary refrigerant radiates heat to the primary refrigerant and condenses. The secondary refrigerant condensed in the main heat exchanger (HEX2)
It flows through the main liquid pipe (26), passes through the collecting liquid pipe (38), and is collected in the second main tank (T2).

After performing such an operation for a predetermined time, the solenoid valves (SV-P1, SV-P2,...) Of the pump circuit (30) are switched.
That is, the pressurized solenoid valve (SV-P) of the first main tank (T1)
1) Close the pressure reducing solenoid valve (SV-V2) of the second main tank (T2), and close the pressure reducing solenoid valve (SV-P) of the second main tank (T2).
2) Open the pressure reducing solenoid valve (SV-V1) of the first main tank (T1). Thereby, the first main tank (T1) is depressurized, and conversely, the second main tank (T2) is pressurized.
For this reason, the liquid refrigerant pushed out from the second main tank (T2) circulates as described above, and the first main tank (T1)
Will be collected.

As described above, each solenoid valve (SV-P1, SV-P2,...)
Performs the switching operation, and continuously circulates the secondary refrigerant in the secondary circuit (20). As a result, the cold heat of the primary circuit (10) is transferred to the indoor heat exchanger (HEX1) to cool the room. The sub tank (ST) pressurized solenoid valve (SV-P
3) The opening and closing of the pressure reducing solenoid valve (SV-V3) is independent of the opening and closing of the solenoid valves (SV-P1, SV-P2, SV-V1, SV-V2) of the main tank (T1, T2). It is done at the timing.

As described above, when depressurizing the main tank (T1, T2) and the sub tank (ST), the gas refrigerant is sucked from these tanks (T1, T2, ST). On the other hand, the secondary circuit (20) is filled with R407C which is a non-azeotropic mixed refrigerant as the secondary refrigerant. Here, when the non-azeotropic mixed refrigerant evaporates, the low-boiling component evaporates first.

Therefore, when recovering the liquid refrigerant by depressurizing the tanks (T1, T2, ST), the tanks (T1, T2, ST)
The gas refrigerant sucked from the gas has a higher proportion of low-boiling components than normal R407C. Then, when the proportion of the low boiling point component in the gas refrigerant increases, the condensation temperature is lower than that of normal R407C. For this reason, if the pressure is reduced by condensing only the gas refrigerant from the main tank (T1, T2) and the sub tank (ST), the low pressure in the primary circuit (10) is reduced in accordance with the decrease in the condensation temperature of the gas refrigerant. It needs to be lowered.

On the other hand, in the first embodiment, the main heat exchanger (HEX2) is configured to also serve as the low-pressure section during the cooling operation.
The gas refrigerant from the main tanks (T1, T2) and the sub tank (ST) is sent to the main heat exchanger (HEX2) together with the gas refrigerant from the indoor heat exchanger (HEX1) to condense. That is, the gas refrigerant having a large amount of low-boiling components from each tank (T1, T2, ST) is mixed with the gas refrigerant from the indoor heat exchanger (HEX1), so that the composition change of the gas refrigerant is reduced, and The composition of the gas refrigerant flowing into the heat exchanger (HEX2) is a normal R407
It is maintained almost the same as C.

<< Heating Operation >> The operation of the heating operation for transferring the heat generated in the primary circuit (10) to the indoor unit (22) will be described with reference to FIG.

In the primary circuit (10), the primary four-way switching valve (12) is switched as shown by a broken line in FIG. 2, and the second solenoid valve (SV-2) and the third solenoid valve are switched. (SV-3) is opened, and the first expansion valve (EV-1) and the second expansion valve (EV-2) are adjusted to a predetermined opening degree. In the primary circuit (10),
The first solenoid valve (SV-1) is closed. When the primary-side compressor (11) is operated in this state, the primary-side refrigerant circulates in the primary-side circuit (10) as shown by the dashed-dotted arrow in FIG.
A heat pump cycle operation is performed.

Specifically, the primary-side refrigerant discharged from the primary-side compressor (11) is divided into two parts and is divided into a main heat exchanger (HEX).
2) and flows toward the heating heat exchanger (HEX3).

The primary refrigerant flowing to the main heat exchanger (HEX2) passes through the primary four-way switching valve (12) and passes through the main heat exchanger (HEX2).
Flow to 2). In the main heat exchanger (HEX2), the primary refrigerant exchanges heat with the secondary refrigerant in the secondary circuit (20). By this heat exchange, the primary refrigerant condenses and the secondary refrigerant evaporates at the same time, and heat is given to the secondary refrigerant. The primary refrigerant condensed in the main heat exchanger (HEX2) is supplied to the second branch pipe (52).
Once flows into the receiver (13). Receiver (1
The primary refrigerant flowing out of 3) returns to the main circuit (15) after flowing through the fourth branch pipe (54). The primary-side refrigerant that has returned to the main circuit (15) is divided into two parts, and is divided into outdoor heat exchangers (HEs).
X6) and the first branch pipe (51).

The primary-side refrigerant flowing to the outdoor heat exchanger (HEX6) is depressurized by the first expansion valve (EV-1), and then passes through the third branch pipe (53). Flows into In the outdoor heat exchanger (HEX6), the primary-side refrigerant evaporates by performing heat exchange with the outside air. The primary-side refrigerant evaporated in the outdoor heat exchanger (HEX6) is drawn into the primary-side compressor (11) through the primary-side four-way switching valve (12).

The primary refrigerant discharged from the primary compressor (11) and traveling to the heating heat exchanger (HEX3) flows into the heating heat exchanger (HEX3) through the fifth branch pipe (55). . In the heating heat exchanger (HEX3), the primary refrigerant is pump circuit (30)
Heat exchange with the secondary-side refrigerant. By this heat exchange, the primary refrigerant is condensed and the secondary refrigerant is evaporated at the same time, and the heating heat exchanger (HEX3) is maintained at a high pressure. The primary refrigerant condensed in the heating heat exchanger (HEX3) flows into the fourth branch pipe (54).
The refrigerant returns to the main circuit (15), merges with the refrigerant flowing to the first branch pipe (51), and flows toward the cooling heat exchanger (HEX4).

The primary-side refrigerant flowing to the cooling heat exchanger (HEX4) flows into the first branch pipe (51), and flows into the second expansion valve (EV-2).
After flowing into the cooling heat exchanger (HEX4), the pressure is reduced. In the cooling heat exchanger (HEX4), the primary refrigerant flows into the secondary circuit (2
It exchanges heat with the secondary refrigerant flowing through the main liquid pipe (25) of (0). Due to this heat exchange, the primary refrigerant becomes the main liquid pipe (25)
Absorbs heat from the secondary-side refrigerant and evaporates. That is, the secondary refrigerant that is condensed in the indoor heat exchanger (HEX1) and flows through the main liquid pipe (25) is cooled, brought into a supercooled state, and maintained in a liquid phase.
The primary refrigerant evaporated in the cooling heat exchanger (HEX4) flows through the first branch pipe (51) and is sucked into the primary compressor (11).

In the secondary circuit (20), the secondary four-way switching valve (23) is switched as shown by a broken line in FIG. 2, and the indoor expansion valve (EV) is adjusted to a predetermined opening. In this state, each pressurizing solenoid valve (SV-P1, SV-P2,
SV-P3) and the pressure reducing solenoid valves (SV-V1, SV-V2, SV-V4) are opened and closed to apply a circulation driving force to the secondary refrigerant. During the heating operation, the third tank pressure reducing solenoid valve (SV-V3) is always closed. The solid arrows in FIG. 2 indicate the flow of the refrigerant when the liquid refrigerant is pushed out from the second main tank (T2) and the liquid refrigerant is collected in the first main tank (T1).

In this state, the pump circuit (30) performs substantially the same operation as in the cooling operation to apply a circulating driving force to the secondary refrigerant. However, during the heating operation,
The operation when depressurizing the second main tank (T1, T2) and the sub tank (ST) is different from that during the cooling operation.

For example, when depressurizing the first main tank (T1), the first tank depressurizing solenoid valve (SV-V1) is opened.
In this state, the first main tank (T1) is connected via the branch pipe (41b) of the first gas recovery pipe (41) and the main liquid pipe (25) of the secondary circuit (20) to the cooling heat exchanger (T1). HEX4).
Here, in the cooling heat exchanger (HEX4), the low-pressure secondary refrigerant flowing through the main liquid pipe (25) is cooled by heat exchange with the primary refrigerant in the primary circuit (10) to be in a supercooled state. It has been. Therefore, the cooling heat exchanger (HEX4) is maintained at a low pressure. For this reason, the gas refrigerant in the first main tank (T1) is sucked into the main liquid pipe (25) and is cooled by the cooling heat exchanger (HEX).
Flow to 4) and condense. Thereby, the pressure of the first main tank (T1) is reduced.

Similarly, when depressurizing the second main tank (T2), the second tank depressurizing solenoid valve (SV-V2) is opened. When depressurizing the sub tank (ST),
Open the tank pressure reducing solenoid valve (SV-V4). That is, during the heating operation, the cooling heat exchanger (HEX4) functions as a low-pressure section in the pump circuit (30) and is recovered from the indoor heat exchanger (HEX1) to the main tanks (T1, T2). It also functions as a liquid phase maintaining means for maintaining the secondary refrigerant in the liquid phase.

By the operation of the pump circuit (30) as described above, a circulation driving force is applied to the secondary refrigerant. And
In the secondary circuit (20), the secondary refrigerant circulates while changing phase between the main heat exchanger (HEX2) and the indoor heat exchanger (HEX1), and is generated in the primary circuit (10). Heat is transferred to the indoor heat exchanger (HEX1).

Specifically, one main tank (T1, T2)
The liquid refrigerant extruded from the outlet flows through the extruding liquid pipe (37) and the secondary four-way switching valve (23), and passes through the main liquid exchanger (HEX2) through the main liquid pipe (26) of the secondary circuit (20). ).
In the main heat exchanger (HEX2), the secondary refrigerant flows into the primary circuit (1
Heat exchange is performed with the primary refrigerant of 0), and the primary refrigerant is heated and evaporated. Thereby, the heat of the primary circuit (10) is given to the secondary refrigerant of the secondary circuit (20).

The gas refrigerant evaporated in the main heat exchanger (HEX2) flows through the main gas pipe (24) and is distributed to the indoor heat exchanger (HEX1) of each indoor unit (22). Indoor heat exchanger (HE
In X1), the secondary refrigerant exchanges heat with room air. By this heat exchange, the secondary-side refrigerant radiates heat to the room air and condenses, thereby heating the room air. Then, the heated room air is supplied again into the room to perform heating.

The secondary refrigerant condensed in the indoor heat exchanger (HEX1) flows into the main liquid pipe (25) through the indoor expansion valve (EV). Thereafter, the secondary refrigerant flows from the main liquid pipe (25) through the secondary four-way switching valve (23) and the recovery liquid pipe (38).
It is collected in the other main tank (T1, T2). that time,
The secondary-side refrigerant is cooled in the cooling heat exchanger (HEX4) to be in a supercooled state. Therefore, the main tank (T1, T
The secondary refrigerant recovered in 2) is maintained in the liquid phase and does not flash.

-Effects of First Embodiment- In the first embodiment, the main heat exchanger (HEX2) of the secondary circuit (20) also serves as the low pressure section of the pump circuit (30) during the cooling operation. I have. In other words, the secondary circuit (2
The main heat exchanger (HEX2), which is indispensable to provide the secondary-side refrigerant of (0) with the heat of the primary circuit (10), is connected to the pump circuit (3).
It is made to function also as a low pressure part of 0). For this reason, it is not necessary to separately provide a heat exchanger for configuring the low-pressure section of the pump circuit (30), and the configuration can be simplified and the cost can be reduced.

The main heat exchanger (HEX2) is a heat exchanger for applying cold or warm heat to the secondary-side refrigerant, and usually employs a large-capacity heat exchanger having a large heat exchange amount. It is.
That is, the capacity of the main heat exchanger (HEX2) is larger than the capacity of the heat exchanger when the low-pressure section of the pump circuit (30) is configured by a separate heat exchanger. Therefore, even if the liquid refrigerant accumulates in the large-capacity main heat exchanger (HEX2), if the amount of accumulated liquid refrigerant is equal, the ratio of the effective heat transfer area which is reduced by this is lower in the low-pressure section. It is smaller than when it is configured with a separate small-capacity heat exchanger.

Therefore, even when the liquid refrigerant is accumulated in the main heat exchanger (HEX2) due to, for example, a sudden change in the operating state, the amount of refrigerant condensed in the main heat exchanger (HEX2) can be secured. Main heat exchanger (HEX2) can be maintained at a sufficiently low pressure. As a result, the suction amount of the gas refrigerant from the main tanks (T1, T2) can be secured regardless of the operation state, and the main tanks (T1, T2) are sufficiently depressurized to drive circulation to the secondary refrigerant. The force can be reliably applied.

In particular, in the first embodiment, the secondary side circuit (2
R40, which is a non-azeotropic mixed refrigerant, as the secondary refrigerant of 0)
7C is adopted. When the gas refrigerant is sucked from the main tank (T1, T2) or the sub tank (ST) for decompression, the gas refrigerant (HEX4) flowing into the cooling heat exchanger (HEX4) flows first because the low-boiling component evaporates first. Secondary side refrigerant)
The ratio of low boiling point components is large. Therefore, if only the secondary refrigerant sucked from the main tank (T1, T2) or the sub tank (ST) is to be condensed, the cooling heat exchanger (HE
When the evaporation temperature of the primary refrigerant in X4) is constant, the condensation temperature of the secondary refrigerant decreases, so that the amount of condensation decreases. In order to maintain the amount of condensation of the secondary refrigerant in the cooling heat exchanger (HEX4), the evaporation temperature of the primary refrigerant in the cooling heat exchanger (HEX4) must be reduced. ), The input to the primary compressor (11) increases.

On the other hand, in the first embodiment, the main heat exchanger (HEX2) also serves as the low-pressure section of the pump circuit (30) during the cooling operation. Therefore, as described above, the gas refrigerant having a large amount of the low boiling point component sucked from the main tank (T1, T2) and the sub tank (ST) is combined with the gas refrigerant having a normal composition ratio from the indoor heat exchanger (HEX1). After mixing, it is introduced into the main heat exchanger (HEX2).

Therefore, the change in the composition ratio of the gas refrigerant flowing into the main heat exchanger (HEX2) can be reduced, and the ordinary R
A gas refrigerant having almost the same composition as 407C is supplied to the main heat exchanger (HE
X2). As a result, the condensing temperature of the refrigerant in the main heat exchanger (HEX2) can be maintained at a constant level, and the amount of refrigerant condensed can be ensured to reliably depressurize the main tank (T1, T2) and sub tank (ST). Becomes

In order to switch between the cooling operation and the heating operation as in the first embodiment, the cooling heat exchanger (HEX4) that functions as the low-pressure section of the pump circuit (30) during the heating operation. It is necessary to provide. Therefore, the number of heat exchangers increases, and in that sense, the configuration becomes complicated.

However, in the first embodiment, the cooling heat exchanger (HEX4) required for the heating operation also functions as the liquid phase maintaining means. That is, the cooling heat exchanger (HEX4) performs both functions of the low-pressure section of the pump circuit (30) and the liquid phase maintaining means during the heating operation. Therefore, it is possible to minimize the increase in the number of heat exchangers and to transfer the heat while minimizing the complexity of the configuration.

Further, the cooling heat exchanger (HEX4) also functions as a liquid phase maintaining means, so that the main liquid pipe (2
The secondary-side refrigerant flowing through 5) is cooled to maintain a supercooled state in a liquid phase. For this reason, the secondary refrigerant recovered to the main tanks (T1, T2) can be reliably converted into a liquid phase, and the refrigerant is flushed, whereby the circulation driving force applied by the pump circuit (30) is reduced. Can be prevented. Therefore, the circulation amount of the secondary refrigerant in the secondary circuit (20) during the heating operation can be secured, and the heating capacity can be sufficiently exhibited.

-Modification of First Embodiment- In the first embodiment, the sub tank (ST) and the buffer tank (BT) can be omitted.

That is, as shown in FIG. 3, the sub-tank (ST), the buffer tank (BT), and the pipes (31c, 37c, 39, 4) connected to the sub-tank (ST), the buffer tank (BT), and the air conditioner (see FIG.
3) is omitted and the configuration of the liquid recovery pipe (34) is changed. The liquid recovery pipe (34) of this modification has one end connected to the lower end of the heating heat exchanger (HEX3) and the other end connected to two branch pipes (34a,
Branched to 34b). Of these branch pipes (34a, 34b), one branch pipe (34a) is connected to one branch pipe (37a) of the liquid pipe for extrusion (37), and the other branch pipe (34b) is connected to the liquid pipe for extrusion. It is connected to the other branch pipe (37b) of (37). Each branch pipe (34a, 34b) is provided with a check valve (CV-18) that allows only the flow of the refrigerant toward the heating heat exchanger (HEX3).

During the operation of the air conditioner, a part of the secondary refrigerant pushed out from the main tanks (T1, T2) flows into the branch pipes (34a, 34b) of the liquid recovery pipe (34). The secondary refrigerant is supplied to the heating heat exchanger (HEX3). In the heating heat exchanger (HEX3), the supplied secondary-side refrigerant evaporates, so that the inside is maintained at a high pressure.

[0122]

Embodiment 2 In Embodiment 2 of the present invention, during a heating operation, a cooling heat exchanger (HEX4) functioning as a low pressure section of a pump circuit (30) and a tank heat exchanger (HEX4) functioning as a liquid phase maintaining means are provided. A heat exchanger (HEX5) is provided. That is, in the first embodiment, the cooling heat exchanger (HEX4) functions as both the low-pressure section and the liquid-phase maintaining means of the pump circuit (30) during the heating operation.
In the second embodiment, the heat exchangers that perform the respective functions are separately provided. Hereinafter, the first embodiment
A description will be given of different parts.

As shown in FIG. 4, in the second embodiment, the pre-tank heat exchanger (HEX5) is provided in the secondary circuit (20) in the middle of the main liquid pipe (25) on the indoor expansion valve (EV) side. Provided.

On the other hand, the cooling heat exchanger (HEX
In (4), one branch pipe (41b) of the first gas recovery pipe (41) and one branch pipe (42b) of the second gas recovery pipe (42) are directly connected to the upper end thereof. . Further, one branch pipe (43b) of the third gas recovery pipe (43) is also connected to the upper end of the cooling heat exchanger (HEX4).

A liquid supply pipe (33) is connected to the cooling heat exchanger (HEX4). This liquid supply pipe (33)
Has one end connected to the lower end of the cooling heat exchanger (HEX4),
The other end is connected to the upstream side of the check valve (CV-5) in the recovery liquid pipe (38).

A sixth branch pipe (56) is added to the primary circuit (10) with the installation of the pre-tank heat exchanger (HEX5). One end of the sixth branch pipe (56) is connected closer to one end than the second expansion valve (EV-2) in the first branch pipe (51), and the other end has a cooling heat exchange in the first branch pipe (51). It is connected closer to the other end than the container (HEX4). And
The sixth branch pipe (56) is provided with a third expansion valve (EV-3) and a heat exchanger before tank (HEX5) in order from one end to the other end. That is, the third expansion valve (EV-3) and the pre-tank heat exchanger (HEX5) and the second expansion valve (EV-2) and the cooling heat exchanger (HEX4) are connected in the primary circuit (10). They are provided in parallel with each other.

-Operating operation- << Cooling operation >> The operating operation during the cooling operation for transferring the cooling heat generated in the primary circuit (10) to the indoor unit (22) will be described with reference to FIG.

In the primary circuit (10), the primary four-way switching valve (12) is switched as shown by the solid line in FIG. 4, and the first solenoid valve (SV-1) is opened to open the first solenoid valve (SV-1). Expansion valve (EV-
1) is adjusted to a predetermined opening. In addition, primary side circuit (10)
Then, the second expansion valve (EV-2), the third expansion valve (EV-3), the second
The solenoid valve (SV-2) and the third solenoid valve (SV-3) are closed.
When the primary-side compressor (11) is operated in this state, the primary-side compressor (11) is operated in the primary-side circuit (10) as shown by a dashed-dotted arrow in FIG.
The secondary refrigerant circulates, and a refrigeration cycle operation is performed.

That is, in the primary circuit (10) of the second embodiment, the refrigerant circulates and the refrigeration cycle operation is performed as in the first embodiment. Specifically, the primary refrigerant discharged from the primary compressor (11) is condensed in the outdoor heat exchanger (HEX6) and then sent to the heating heat exchanger (HEX3) to heat the secondary refrigerant. I do. After that, the primary refrigerant is the first expansion valve (EV-1)
Is sent to the main heat exchanger (HEX1) and evaporates by absorbing heat from the secondary refrigerant. The evaporated primary-side refrigerant is sucked into the primary-side compressor (11) again, and repeats this circulation.

In the secondary circuit (20), the secondary four-way switching valve (23) is switched as shown by the solid line in FIG. 4, and the indoor expansion valve (EV) is adjusted to a predetermined opening. In this state, each pressurizing solenoid valve (SV-P1, SV-P2,
SV-P3) and the respective pressure-reducing solenoid valves (SV-V1, SV-V2, SV-V3) are opened and closed to apply a circulation driving force to the secondary refrigerant.

That is, the operations in the secondary circuit (20) and the pump circuit (30) are the same as those in the first embodiment.
Then, in the secondary circuit (20), the secondary refrigerant circulates in a phase-change manner between the main heat exchanger (HEX2) and the indoor heat exchanger (HEX1), and is circulated in the primary circuit (10). The generated cold is transferred to the indoor heat exchanger (HEX1).

<< Heating Operation >> The operation during the heating operation for transferring the heat generated in the primary circuit (10) to the indoor unit (22) will be described with reference to FIG.

In the primary circuit (10), the primary four-way switching valve (12) is switched as shown by a broken line in FIG. 5, and the second solenoid valve (SV-2) and the third solenoid valve are switched. (SV-3) is opened, and the first expansion valve (EV-1), the second expansion valve (EV-2), and the third expansion valve (EV-3) are adjusted to a predetermined opening degree. Also, 1
In the secondary circuit (10), the first solenoid valve (SV-1) is closed. When the primary-side compressor (11) is operated in this state, the primary-side refrigerant circulates in the primary-side circuit (10) as indicated by a dashed-dotted arrow in FIG. 5, and a heat pump cycle operation is performed. That is, in the primary side circuit (10) of the second embodiment,
The primary-side refrigerant circulates in substantially the same manner as in the first embodiment. However, the following points are different from those of the first embodiment.

Specifically, the primary refrigerant flowing into the first branch pipe (51) is divided into two parts and then flows toward the cooling heat exchanger (HEX4) and the tank front heat exchanger (HEX5). .

[0135] The primary refrigerant flowing to the cooling heat exchanger (HEX4) flows through the first branch pipe (51) as it is, and is depressurized by the second expansion valve (EV-2). Flows into In the cooling heat exchanger (HEX4), the primary refrigerant exchanges heat with the gas refrigerant in the pump circuit (30). By this heat exchange, the primary refrigerant evaporates and the pump circuit (3
The gas refrigerant of 0) condenses, and the cooling heat exchanger (HEX4) is maintained at a low pressure.

On the other hand, the primary-side refrigerant flowing to the pre-tank heat exchanger (HEX5) flows into the sixth branch pipe (56) and is depressurized by the third expansion valve (EV-3). Tableware (HEX5)
Flows into In the pre-tank heat exchanger (HEX5), the primary refrigerant exchanges heat with the secondary refrigerant flowing through the main liquid pipe (25) of the secondary circuit (20). By this heat exchange, the primary refrigerant absorbs heat from the secondary refrigerant in the main liquid pipe (25) and evaporates. That is, the secondary refrigerant that is condensed in the indoor heat exchanger (HEX1) and flows through the main liquid pipe (25) is cooled, brought into a supercooled state, and maintained in a liquid phase.

The primary-side refrigerant evaporated in the cooling heat exchanger (HEX4) and the heat exchanger in front of the tank (HEX5) joins the first refrigerant after joining.
Flows through the branch pipe (51). And this primary side refrigerant is
The primary refrigerant (11) is sucked into the primary compressor (11) together with the primary refrigerant evaporated in the outdoor heat exchanger (HEX6).

In the secondary circuit (20), the secondary four-way switching valve (23) is switched as shown by a broken line in FIG. 5, and the indoor expansion valve (EV) is adjusted to a predetermined opening. In this state, each pressurizing solenoid valve (SV-P1, SV-P2,
SV-P3) and the pressure reducing solenoid valves (SV-V1, SV-V2, SV-V4) are opened and closed to apply a circulation driving force to the secondary refrigerant. That is, the secondary circuit (20) and the pump circuit (30) of the second embodiment operate almost in the same manner as the first embodiment, but differ in the following points.

In the secondary circuit (20), the main heat exchanger (HEX
The secondary refrigerant circulates while changing phase between 2) and the indoor heat exchanger (HEX1), and the heat generated in the primary circuit (10) is transferred to the indoor heat exchanger (HEX1). At this time, the secondary-side refrigerant condensed in the indoor heat exchanger (HEX1) flows into the pre-tank heat exchanger (HEX5) through the main liquid pipe (25). And
Main tanks (T1, T2) that are cooled by heat exchange with the primary refrigerant and maintained in a supercooled state and maintained in the liquid phase
Will be collected.

When depressurizing the main tank (T1, T2) and the sub-tank (ST), the respective pressure reducing solenoid valves (SV-V1, SV-V2, SV-V4) are opened, and these tanks (T1, T1) are opened. T2, S
The gas refrigerant is sucked from T) to the cooling heat exchanger (HEX4).
In other words, the main tank (T1, T2) and sub tank (ST)
Only the gas refrigerant (secondary refrigerant) from is introduced into the cooling heat exchanger (HEX4) to be condensed. The condensed gas refrigerant is
The liquid is introduced into the collection liquid pipe (38) through the liquid supply pipe (33), and is collected in the main tanks (T1, T2) together with the liquid refrigerant flowing through the collection liquid pipe (38).

-Modification of Second Embodiment- In the second embodiment, the sub tank (ST) and the buffer tank (BT) can be omitted.

That is, as shown in FIG. 6, the sub-tank (ST), the buffer tank (BT), and the pipes (31c, 37c, 39, 4) connected to the sub-tank (ST) and the buffer tank (BT) are provided from the air conditioner of the second embodiment (see FIG. 4).
3) is omitted and the configuration of the liquid recovery pipe (34) is changed. The liquid recovery pipe (34) of this modification has one end connected to the lower end of the heating heat exchanger (HEX3) and the other end connected to two branch pipes (34a,
Branched to 34b). Of these branch pipes (34a, 34b), one branch pipe (34a) is connected to one branch pipe (37a) of the liquid pipe for extrusion (37), and the other branch pipe (34b) is connected to the liquid pipe for extrusion. It is connected to the other branch pipe (37b) of (37). Each branch pipe (34a, 34b) is provided with a check valve (CV-18) that allows only the flow of the refrigerant toward the heating heat exchanger (HEX3).

During the operation of the air conditioner, part of the secondary refrigerant pushed out from the main tanks (T1, T2) flows into the branch pipes (34a, 34b) of the liquid recovery pipe (34). The secondary refrigerant is supplied to the heating heat exchanger (HEX3). In the heating heat exchanger (HEX3), the supplied secondary-side refrigerant evaporates, so that the inside is maintained at a high pressure.

[Brief description of the drawings]

FIG. 1 is a piping diagram illustrating a flow of a refrigerant during a cooling operation of an air conditioner according to a first embodiment.

FIG. 2 is a piping diagram illustrating a flow of a refrigerant during a heating operation of the air conditioner according to the first embodiment.

FIG. 3 is a piping diagram of an air conditioner according to a modification of the first embodiment.

FIG. 4 is a piping diagram illustrating a flow of a refrigerant during a cooling operation of the air conditioner according to the second embodiment.

FIG. 5 is a piping diagram illustrating a flow of a refrigerant during a heating operation of the air conditioner according to the second embodiment.

FIG. 6 is a piping diagram of an air conditioner according to a modification of the second embodiment.

[Explanation of symbols]

 (10) Primary circuit (cold heat source, hot heat source) (20) Secondary circuit (heat transfer circuit) (30) Pump circuit (transport means) (T1) First main tank (T1) Second main tank ( HEX1) Indoor heat exchanger (use side heat exchanger) (HEX2) Main heat exchanger (HEX3) Heating heat exchanger (high pressure section) (HEX4) Cooling heat exchanger

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Osamu Tanaka, Inventor 1304, Kanaokacho, Sakai-shi, Osaka Daikin Industries, Ltd. Sakai Plant Kanaoka Plant

Claims (4)

[Claims] 1. A cold heat source (10) for generating cold heat, a main heat exchanger (HEX2), a refrigerant conveying means (30), and a use side heat exchanger (HEX1) are connected by piping, and a main heat exchanger (HEX1) is provided. HEX2)
And a heat transfer circuit (20) connected to a cold heat source (10) for applying cold heat to the transfer refrigerant and circulating the transfer refrigerant to transfer the cold heat to the use side heat exchanger (HEX1). An apparatus, wherein the transport means (30) is connected to a heat transport circuit (20) and stores a pair of transport refrigerants (T1, T2);
A high-pressure section (HEX3) for supplying the evaporated refrigerant to the tanks (T1, T2) to pressurize the tanks (T1, T2), and the main heat exchanger (HEX2) At the time of transfer, the transfer means (30) is configured to condense gas refrigerant sucked from the tanks (T1, T2) in order to apply cold to the transfer refrigerant and to depressurize the tanks (T1, T2). ) Is to pressurize one tank (T1) to push out the transfer refrigerant from the tank (T1), and at the same time, depressurize the other tank (T2) and collect the transfer refrigerant to the tank (T2). And a refrigeration apparatus configured to apply a circulating driving force to the transporting refrigerant by performing the following. 2. The refrigeration apparatus according to claim 1, wherein the transfer refrigerant of the heat transfer circuit (20) is a non-azeotropic mixed refrigerant. 3. The refrigeration apparatus according to claim 1, further comprising a heat source (10) for applying heat to the transfer refrigerant of the heat transfer circuit (20), wherein the heat transfer circuit (20) The transfer of the cold heat and the transfer of the warm heat are performed by circulating the refrigerant, and the transfer means (30) is provided with a cooling heat exchanger (30) for condensing the gas refrigerant sucked from the tanks (T1, T2) during the transfer of the hot heat. Refrigeration equipment equipped with HEX4). 4. The refrigeration apparatus according to claim 3, wherein the cooling heat exchanger (HEX4) is provided with a tank (TEX) for transferring the heat.
In order to condense the gas refrigerant sucked from the tank (T1, T2) and maintain the transport refrigerant recovered in the tanks (T1, T2) in the liquid phase, the use side heat exchanger (HEX1) , A refrigeration apparatus configured to cool the transfer refrigerant sent to T2) to a supercooled state.