JP2002139262A - Heat conveying apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To process a gas refrigerant separated by a gas-liquid separator in a heat conveying apparatus for circulating the refrigerant in a secondary circuit to convey cold, with avoiding such problems as cost increase due to increase of constituent apparatus. SOLUTION: In a secondary circuit (20), a secondary refrigerant is circulated between a main heat exchanger (HEX2) and an indoor heat exchanger (HEX1). A primary circuit (10) is connected to the main heat exchanger (HEX2) to apply cold to the secondary refrigerant. The gas-liquid separator (71) directly follows the main heat exchanger (HEX2) to send only the liquid refrigerant to second main liquid piping (26). The gas refrigerant separated by the separator (71) is returned back to the main heat exchanger (HEX2) through a gas return pipe (72).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat transfer device for transferring cold heat to a use side by a refrigerant circulating in a circuit.

[0002]

2. Description of the Related Art Heretofore, there has been known a heat transfer device having a closed circuit in which a refrigerant circulates and applying cold heat of a cold heat source to the circulating refrigerant and transferring the same to a user side. For example, Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. 218344 discloses a method in which a so-called heat-driven pump imparts a circulating drive force to a refrigerant. In this publication, an air conditioner is configured by combining a primary circuit as a heat source with a secondary circuit as a heat transfer device.

In the primary circuit, a 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, while the secondary refrigerant of the secondary circuit is 1 in the main heat exchanger. Heat is released to the primary refrigerant in the secondary circuit 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 room air and evaporates, thereby cooling the room air. The evaporated secondary refrigerant is sent to the main heat exchanger and condensed again, and repeats this circulation.

At this time, in the secondary circuit of the heat transfer device, the refrigerant is circulated by a so-called heat driven 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 liquid 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.

Here, in general, in a pump for imparting a circulating force to a liquid, if gas is mixed into the liquid to be sucked, the pump cannot exhibit sufficient performance. This point is the same for a heat driven pump. For this reason, in the heat transfer device, the refrigerant collected in the tank of the secondary circuit is introduced into the gas-liquid separator, the gas refrigerant is separated, and only the liquid refrigerant is sent to the tank.

When the gas refrigerant is separated by the gas-liquid separator, it is necessary to condense the separated gas refrigerant by some means. Therefore, in the heat transfer device, a heat exchanger for cooling and condensing the separated gas refrigerant is separately provided.

[0009]

However, if a heat exchanger for condensing the gas refrigerant separated by the gas-liquid separator is newly provided as in the above heat transfer device, the components of the heat transfer device are not provided. Will increase. For this reason, the configuration of the heat transfer device becomes complicated, and the manufacturing cost increases.

The present invention has been made in view of the above circumstances, and has as its object to perform processing of a separated gas refrigerant while avoiding problems such as cost increase due to an increase in the number of components, and to carry out heat transfer. The purpose is to make full use of the capabilities of the device.

[0011]

Means for Solving the Problems The first solution taken by the present invention is a main heat exchanger (HEX2) and a use side heat exchanger (HE).
X1) Heat transfer circuit (20) filled with transfer refrigerant
A transfer means (30) for applying a circulating driving force to the transfer refrigerant of the heat transfer circuit (20);
In 0), the heat for carrying out at least the cold transfer operation of transferring the cooling heat imparted to the transfer refrigerant in the main heat exchanger (HEX2) to the use side heat exchanger (HEX1) by circulating the transfer refrigerant while changing the phase. It is intended for transport devices. Gas-liquid separation means for separating the gas refrigerant from the transfer refrigerant exiting the main heat exchanger (HEX2) during the cold heat transfer operation and sending it back to the main heat exchanger (HEX2) to condense the separated gas refrigerant. (7
0), and at the time of cold and hot transfer operation, the transfer means (30)
Is to suck the transport refrigerant from which the gas refrigerant has been removed by the gas-liquid separation means (70) and send it to the use side heat exchanger (HEX1).

According to a second aspect of the present invention, in the first aspect, the gas-liquid separation means (70) includes a separation vessel (70) for separating the carrier refrigerant into a liquid refrigerant and a gas refrigerant. 71) and a return line (72) for guiding the gas refrigerant separated in the separation container (71) to the main heat exchanger (HEX2).

According to a third aspect of the present invention, in the second aspect, the separation vessel (71) of the gas-liquid separation means (70) is provided when the heat transfer circuit (20) performs a cold and hot transfer operation. This is provided immediately after the main heat exchanger (HEX2) in the refrigerant circulation direction.

According to a fourth aspect of the present invention, in the second aspect, the transfer medium is transferred via a switching mechanism (23) for reversing the circulation direction of the transfer refrigerant in the heat transfer circuit (20). Means (30) is connected to the heat transfer circuit (20), and in the cold transfer operation, the circulation direction of the transfer refrigerant is reversed so that the heat given to the transfer refrigerant by the main heat exchanger (HEX2) is removed. The hot and cold transfer operation for transferring to the use side heat exchanger (HEX1) is configured so as to be switched with the cold transfer operation, while the separation vessel (71) of the gas-liquid separation means (70) is provided with the transfer means (30). ) And the switching mechanism (23).

According to a fifth aspect of the present invention, in the above first, second, third or fourth solving means, the transport means (30) is connected to a heat transport circuit (20) to transport the heat. A pair of tanks (T1, T2) for storing refrigerant for use, a high-pressure unit (HEX3) for supplying the evaporated gas refrigerant to the tank (T1) and pressurizing the tank (T1), A low-pressure section (HEX4) for condensing the gas refrigerant sucked from the tank (T2) and depressurizing the tank (T2);
1) At the same time, the transfer refrigerant is extruded from the tank (T1) by pressurizing, and at the same time, the other tank (T2) is depressurized and the transfer refrigerant is sucked into the tank (T2). It is configured to provide a circulation driving force.

According to a sixth aspect of the present invention, in the first, the second, the third, the fourth or the fifth aspect of the present invention, the transfer refrigerant is a non-azeotropic refrigerant mixture. is there.

[Operation] In the first solution, the heat transfer device is provided with the heat transfer circuit (20) and the transfer means (30). The heat transfer circuit (20) is filled with a transfer refrigerant and is connected to a transfer means (30). Heat transfer circuit (20)
In the embodiment, the circulation driving force is applied by the operation of the transfer means (30), and the transfer refrigerant circulates. The heat transfer device performs a cold transfer operation of transferring cold heat to the utilization side by circulating the transfer refrigerant in the heat transfer circuit (20) while changing the phase.

More specifically, in the main heat exchanger (HEX2), cold heat is applied to the transfer refrigerant, whereby the transfer refrigerant is condensed. The transfer refrigerant condensed in the main heat exchanger (HEX2) is sucked by the transfer means (30). Thereafter, the transfer refrigerant is provided with a circulating force by the transfer means (30),
It flows toward the use side heat exchanger (HEX1). In the use side heat exchanger (HEX1), the transfer refrigerant absorbs heat from the target and evaporates. That is, the cold transferred to the use-side heat exchanger (HEX1) is used to cool the object. The transfer refrigerant evaporated in the use side heat exchanger (HEX1) is transferred to the main heat exchanger (HE
It is sent to X2), condensed, and repeats this circulation.

Here, in the main heat exchanger (HEX2), the transfer refrigerant is not always completely condensed. Further, even when the transfer refrigerant is entirely in the liquid phase in the main heat exchanger (HEX2), the transfer refrigerant is lost due to the pressure loss from the main heat exchanger (HEX2) to the transfer means (30). Sometimes flush. That is, the transfer refrigerant flowing from the main heat exchanger (HEX2) to the transfer means (30) may be in a gas-liquid two-phase state.

Therefore, in this solution, the main heat exchanger (HE
The transfer refrigerant from X2) to the transfer means (30) is introduced into the gas-liquid separation means (70), the gas refrigerant is separated from the transfer refrigerant, and only the liquid refrigerant is sent out to the transfer means (30). Further, the gas-liquid separation means (70) sends the gas refrigerant separated from the transfer refrigerant back to the main heat exchanger (HEX2). As described above, in the main heat exchanger (HEX2), cold heat is applied to the transfer refrigerant. Therefore, in the main heat exchanger (HEX2), not only the transfer refrigerant (gas refrigerant) from the use side heat exchanger (HEX1) but also the gas refrigerant from the gas-liquid separation means (70) is condensed.

In the second solution, the gas-liquid separating means (70) is provided with a separation vessel (71) and a return pipe (72). The transfer refrigerant flowing from the main heat exchanger (HEX2) to the transfer means (30) is introduced into the separation vessel (71). In the separation container (71), the introduced transfer refrigerant is separated into a liquid refrigerant and a gas refrigerant. The gas refrigerant separated in the separation vessel (71) is sent back to the main heat exchanger (HEX2) through the return pipe (72). On the other hand, the liquid refrigerant separated in the separation container (71) is sent out from the separation container (71) to the transport means (30).

In the third solution, the separation vessel (71) of the gas-liquid separation means (70) is provided in the heat transfer circuit (20). The separation container (71) is disposed immediately after the main heat exchanger (HEX2) in the refrigerant circulation direction during the cold heat transfer operation. The “immediately after” here means the main heat exchanger (HEX2)
Does not mean that the separation vessel (71) and the separation vessel (71) are close to each other in distance, but means that the main heat exchanger (HEX2) and the separation vessel (71) are directly connected by piping etc. . That is, no other components are provided between the main heat exchanger (HEX2) and the separation vessel (71) in the heat transfer circuit (20). However, as long as the main heat exchanger (HEX2) and the separation vessel (71) are directly connected, the main heat exchanger (HEX2)
2) and the separation container (71) may be in close proximity.

In the fourth solution, the heat transfer device switches between a cold transfer operation and a hot transfer operation. Also,
The transfer means (30) is connected to the heat transfer circuit (20) via the switching mechanism (23). During the warm transfer operation, the transfer refrigerant circulates in the heat transfer circuit (20) in a direction opposite to that in the cool transfer operation. The reversal of the circulation direction of the transfer refrigerant is as follows.
This is performed by the switching mechanism (23).

Specifically, the transfer refrigerant is sent into the main heat exchanger (HEX2) by the transfer means (30). In the main heat exchanger (HEX2), warming is imparted to the transfer refrigerant, whereby the transfer refrigerant evaporates. The transfer refrigerant evaporated in the main heat exchanger (HEX2) is sent to the use side heat exchanger (HEX1). In the use side heat exchanger (HEX1), the transfer refrigerant radiates heat to the object and condenses. In other words, use side heat exchanger (HEX1)
The heat transferred to is used to heat the object. The transfer refrigerant condensed in the use side heat exchanger (HEX1)
It is sucked by the conveying means (30) and sent out again to the main heat exchanger (HEX2).

In the above solution, the gas-liquid separation means (70)
The separation container (71) is provided at a position downstream of the switching mechanism (23) and upstream of the transfer means (30) in the flow direction of the transfer refrigerant. During cold heat transfer operation,
The transfer refrigerant from the main heat exchanger (HEX2) is transferred to the switching mechanism (2
It is introduced into the separation vessel (71) through 3). Then, the transfer means (30) sucks the transfer refrigerant from which the gas refrigerant has been removed in the separation container (71). On the other hand, the gas refrigerant separated in the separation vessel (71) is sent back to the main heat exchanger (HEX2) through the return pipe (72).

In the fifth solution, a so-called heat-driven pump is used instead of a general mechanical pump. Specifically, the transfer means (30) includes a pair of tanks (T1, T2), and the tanks (T1, T2) communicate with the heat transfer circuit (20). First, one tank (T1) is communicated with the high pressure section (HEX3), and the high pressure gas refrigerant of the high pressure section (HEX3) is introduced to pressurize the tank (T1). At the same time, the other tank (T2) is communicated with the low pressure part (HEX4), and the gas refrigerant is sucked into the low pressure part (HEX4) to depressurize the tank (T2). Then, the transfer refrigerant stored in one tank (T1) is pushed out to the heat transfer circuit (20), and the transfer refrigerant from the heat transfer circuit (20) is collected in the other tank (T2). At this time, the transport refrigerant from which the gas refrigerant has been separated by the gas-liquid separation means (70) is supplied to the depressurized tank (T2).
That is, only the liquid refrigerant is recovered.

Subsequently, on the contrary, one of the tanks (T
1) communicates with the low pressure section (HEX4) to reduce the pressure,
The other tank (T2) communicates with the high-pressure section (HEX3) and is 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). . By carrying out the above operations alternately, the transporting means (30) of the present solution provides a heat transporting circuit (20).
A circulation driving force is applied to the transfer refrigerant.

In the sixth 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
It is a mixed refrigerant composed of three components of R25 and R134a, and its composition ratio is expressed as R32: 23% /
R125: 25% / R134a: 52%.

[0029]

According to the present invention, the gas refrigerant is separated from the transfer refrigerant by the gas-liquid separation means (70) during the cold heat transfer operation, and only the transfer refrigerant which is the liquid refrigerant is sent to the transfer means (30). be able to. For this reason, it is possible to reliably apply the circulation driving force to the transfer refrigerant by the transfer means (30),
By ensuring the circulation amount of the transfer refrigerant in the heat transfer circuit (20), transfer of cold heat or the like can be reliably performed.

According to the present invention, the gas-liquid separation means (7
The gas refrigerant separated in 0) is sent back to the main heat exchanger (HEX2), and the gas refrigerant is condensed in the main heat exchanger (HEX2). Therefore, it is not necessary to add a heat exchanger for condensing the separated gas refrigerant, and it is possible to keep the configuration of the heat transfer device simple and avoid an increase in manufacturing cost.

Here, the gas-liquid separation means (70) according to the present invention.
If the heat transfer device is not installed, the main heat exchanger (HEX2)
In order to use only the liquid refrigerant as the transfer refrigerant coming out of the storage device and flowing to the transfer means (30), it is necessary to sufficiently cool the transfer refrigerant in the main heat exchanger (HEX2). However, in general, the heat transfer coefficient when changing the sensible heat of the liquid refrigerant is
This is considerably lower than the heat transfer coefficient when condensing the gas refrigerant. For this reason, if an attempt is made to increase the degree of supercooling of the transfer refrigerant, it is necessary to increase the heat transfer area for that purpose, which leads to an increase in the size of the main heat exchanger (HEX2).

On the other hand, when the gas-liquid separation means (70) is provided as in the present invention, when the supercooling degree of the transfer refrigerant at the outlet of the main heat exchanger (HEX2) is hardly kept,
Even when the degree of supercooling is not at all, or even in the case of a gas-liquid two-phase state, the gas refrigerant is separated by the gas-liquid separation means (70) and only the liquid refrigerant is transferred to the transport means (30). Can be sent. Therefore, according to the present invention, the main heat exchanger (HE
In X2), there is no need to add a subcooling degree to the transfer refrigerant, and the main heat exchanger (HEX2) can be downsized.

As described above, in the sixth solution,
In the first to fifth solving means, the non-azeotropic mixed refrigerant is used as the transfer refrigerant. Among them, particularly when the non-azeotropic mixed refrigerant is used as the transfer refrigerant in the fifth solution,
The following effects can be obtained.

To explain this point, in the fifth solution, the transport means (30) is constituted by a so-called heat-driven pump, and when the tanks (T1, T2) are depressurized to recover the liquid refrigerant, The gas refrigerant is sucked from (T1, T2) to the low-pressure section (HEX4) of the conveying means (30) to be condensed. On the other hand, when the transfer refrigerant, which is a non-azeotropic mixed refrigerant, evaporates, the low-boiling component having a relatively low boiling point among the components evaporates first.

Therefore, when the pressure in the tank (T1, T2) is reduced, the gas refrigerant sucked from the tank (T1, T2) has a higher proportion of the low-boiling component than the non-azeotropic mixed refrigerant having a normal composition. It will be. For this reason, when trying to condense the gas refrigerant sucked from the tanks (T1, T2) in the low-pressure section (HEX4), the condensed amount decreases with a decrease in the condensing temperature of the gas refrigerant, and the tank (T1, T2) Insufficient pressure reduction. In addition, if an attempt is made to maintain the amount of gas refrigerant condensed, the energy required for condensing the gas refrigerant increases.

On the other hand, in the present solution, the gas-liquid separation means (70) is provided to separate the gas refrigerant from the transport refrigerant sucked into the tanks (T1, T2). The composition of the separated gas refrigerant is high in low-boiling components. Therefore, the composition of the liquid refrigerant sent from the gas-liquid separation means (70) to the tanks (T1, T2) is low in low-boiling components. For this reason, the gas refrigerant sucked by the low-pressure part (HEX4) when depressurizing the tanks (T1, T2) also has a low proportion of low-boiling components. Therefore, even when a non-azeotropic mixed refrigerant is used as the transfer refrigerant, an increase in energy required for condensing the gas refrigerant in the low-pressure section (HEX4) can be avoided.

[0037]

Embodiment 1 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The first embodiment is an air conditioner configured using the heat transfer device according to the present invention.

<< 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 pair of connecting pipes including a liquid-side connecting pipe (27) and a gas-side connecting pipe (28).

The air conditioner includes a primary circuit (10),
A secondary circuit (20) is provided. A pump circuit (30) is connected to 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 reheat heat exchanger (HEX
7), an indoor expansion valve (EV), an indoor heat exchanger (HEX1) that is a use side heat exchanger, a main heat exchanger (HEX2), and a gas-liquid separator (71) that is a separation vessel. The pipes are connected in order. Of the secondary circuit (20), the secondary four-way switching valve (23), the reheat heat exchanger (HEX7), and the main heat exchanger (HEX
2) and the gas-liquid separator (71) are 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
Between V), a first main liquid pipe (25) is provided.
One end of the first 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). A reheat heat exchanger (HEX7) is provided in the middle of the first main liquid pipe (25). In the first main liquid pipe (25), a part extending from the outdoor unit (29) to each indoor unit (22) is a liquid side communication pipe (2).
7) Make up.

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

The gas-liquid separator (71) is connected to the second main liquid pipe (26).
Is provided on the way. This gas-liquid separator (71) is a cylindrically-shaped hermetically-closed container formed in a slightly elongated shape. The gas-liquid separator (71) separates the secondary refrigerant sent through the second main liquid pipe (26) into a liquid phase (liquid refrigerant) and a gas phase (gas refrigerant), and Only the refrigerant is returned to the second main liquid pipe (2
6) It is configured to flow out. Further, one end of a gas return pipe (72) constituting a return pipe is connected to the upper end of the gas-liquid separator (71). This gas return pipe (7
The other end of 2) is connected to the main heat exchanger (H
EX2) is connected near the upper end. And the gas-liquid separator (71) and the gas return pipe (72) constitute a gas-liquid separator (70).

The secondary circuit (20) is filled with R407C, which is a non-azeotropic refrigerant mixture, as a secondary refrigerant. Note that a single refrigerant such as R22 may be used as the secondary refrigerant. In the secondary circuit (20), the secondary refrigerant, which is the transfer refrigerant, changes phase while circulating, 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) has a heating heat exchanger (HEX3) that is a high pressure section and a cooling heat exchanger (HEX3) that is a low pressure section.
4), a first main tank (T1), and a second main tank (T2). This pump circuit (30) has two main tanks (T1, T2) connected to the secondary circuit (20).
Is alternately connected to the heating heat exchanger (HEX3) and the cooling heat exchanger (HEX4) to increase and decrease the pressure in the tank, thereby
The secondary circuit of the secondary circuit (20) is configured to apply a circulation driving force to the secondary refrigerant. The pump circuit (30) includes a sub tank (ST) and a buffer tank (BT).

The first main tank (T1) and the second main tank (T2) are connected with a recovery liquid pipe (38) and an extrusion liquid pipe (37), respectively. The recovery liquid pipe (38) and the extrusion liquid pipe (37) are connected to the secondary circuit (20) via a secondary four-way switching valve (23).

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 recovery 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 four-way switching valve (23) communicates with the extruding liquid pipe (37) and the first main liquid pipe (25), and collects the collecting liquid pipe (38) and the second main liquid pipe (23). 26) (the state shown by the solid line in FIG. 1), the liquid pipe for extrusion (37) and the second
The main liquid pipe (26) communicates with the recovery liquid pipe (38) and the first
It is configured to switch to a state in which the main liquid pipe (25) communicates (a state indicated by a broken line in FIG. 1). By switching the secondary four-way switching valve (23), the circulation direction of the secondary refrigerant in the secondary circuit (20) is switched.
In other words, the secondary four-way switching valve (23) constitutes switching means.

The heating heat exchanger (HEX3) comprises first and second heat exchangers (HEX3).
This is for pressurizing the main tank (T1, T2) and the sub tank (ST). The heating heat exchanger (HEX3) is connected to the first and second main tanks (T1, T1) via a gas supply pipe (31).
2) and connected to each of the sub tanks (ST). One end of the gas supply pipe (31) is a heating heat exchanger (HEX3)
The other end is connected to three branch pipes (31a, 31b, 31).
c) Branched. Branch pipe (31a) of gas supply pipe (31)
To 31c) are connected to the upper ends of the first and second main tanks (T1, T2) and the sub tank (ST). These branch pipes (31a to 31c) have 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 This allows these tanks (T1, T2, S
T) is pressurized.

The buffer tank (BT) and the heating 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). The cooling heat exchanger (HEX4) is connected to the first and second main tanks (T1, T1) via a gas recovery pipe (32).
2) and connected to each of the sub tanks (ST). The gas recovery pipe (32) has three branch pipes (32a, 32
b, 32c), and the other end is connected to the upper end of the cooling heat exchanger (HEX4). Branch pipe (32) of gas recovery pipe (32)
a to 32c) are connected to the upper ends of the first and second main tanks (T1, T2) and the sub tank (ST). These branch pipes (32a to 32c) have first to third tank pressure reducing solenoid valves (SV
-V1, SV-V2, SV-V3).

The cooling heat exchanger (HEX4) is connected to the first and second main tanks (T1, T2) via a liquid supply pipe (33).
Is connected to One end of the liquid supply pipe (33) is connected to the lower end of the cooling heat exchanger (HEX4), and the other end is branched into two branch pipes (33a, 33b). The branch pipes (33a, 33b) of the liquid supply pipe (33) are connected to the lower ends of the first and second main tanks (T1, T2). Each of the branch pipes (33a, 33b) is provided with a check valve (CV-2) that allows only the flow of the refrigerant toward each of the main tanks (T1, T2).

The cooling heat exchanger (HEX4) is connected to a gas recovery pipe (3
The gas refrigerant is sucked from the first and second main tanks (T1, T2) and the sub tank (ST) through 2) and condensed. As a result, the pressure in the tanks (T1, T2, ST) is reduced. The condensed refrigerant is returned to the first and second main tanks (T1, T2) through the liquid supply pipe (33).

Each main tank (T1, T2) is installed at a position lower than the cooling heat exchanger (HEX4). The sub tank (ST) is installed at a higher position than the heating heat exchanger (HEX3). The buffer tank (B
T) is arranged above the heating heat exchanger (HEX3) and below the sub tank (ST). This buffer tank (BT) is equipped with a heating heat exchanger (HE
It is provided to stably supply the liquid refrigerant to X3).

<< Configuration of Primary Side Circuit >> The above primary side circuit (1
0) constitutes a heat source circuit. This primary side circuit (1
0) is the main circuit (15) and the first to sixth branch pipes (51
~ 56).

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 filled with R407C as a primary refrigerant. In addition, as a primary side refrigerant,
A single refrigerant such as R22 may be used. In the main circuit (15), the primary-side refrigerant, which is the heat-source-side refrigerant, circulates while changing its phase, and performs a vapor compression refrigeration cycle. In the main circuit (15), the cooling operation and the heat pump operation are performed by switching the direction of circulation of the primary refrigerant by switching the primary four-way switching valve (12).

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) and the first expansion valve (EV) in the main circuit (15).
-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 closer to one end than the second expansion valve (EV-2) in the first branch pipe (51), and the other end is connected to the primary circuit in the main circuit (15). It is connected between the side four-way switching valve (12) and the outdoor heat exchanger (HEX6). The second branch pipe (52) has an electric valve (EV-F) and a reheat heat exchanger (HEX7) in order from one end to the other end.
Are provided.

One end of the third branch pipe (53) is connected between the receiver (13) and the first solenoid valve (SV-1) in the main circuit (15), 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). The third branch pipe (53) is provided with a third solenoid valve (SV-3).

One end of the fourth branch pipe (54) is connected between the first expansion valve (EV-1) and the check valve (CV-8) in the main circuit (15), and the other end is connected to the main circuit. It is connected between the outdoor heat exchanger (HEX6) and the check valve (CV-6) in (15). The fourth branch pipe (54) 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 fifth branch pipe (55) 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 fifth branch pipe (55) is provided with a check valve (CV-9) that allows only the flow of the refrigerant from one end to the other end.

One end of the sixth branch pipe (56) is connected between the discharge side of the primary compressor (11) and the primary four-way switching valve (12) in the main circuit (15). Check valve (CV-7) and heating heat exchanger (HEX3) at the end of the main circuit (15)
Is connected between. The sixth branch pipe (56) is provided with a fourth solenoid valve (SV-4).

The primary side four-way switching valve (12) is connected to the discharge side of the primary side compressor (11) and the outdoor heat exchanger (HEX6).
A state where the suction side of the secondary compressor (11) communicates with the main heat exchanger (HEX2) (a state shown by a solid line in FIG. 1), and a discharge side of the primary compressor (11) and the main heat exchanger (HEX2) HEX2) is communicated and the state is switched to a state in which the suction side of the primary compressor (11) communicates with the outdoor heat exchanger (HEX6) (the state shown by the broken line in FIG. 1). The switching operation of the primary four-way switching valve (12) switches between the cooling operation and the heat pump operation.

-Operating operation- << Cooling operation >> Primary side circuit (1
The operation during the cooling operation for transferring the cold generated in step (0) 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), the second expansion valve (EV-2) and the electric valve (EV-F) are adjusted to a predetermined opening degree. In the primary circuit (10), the third solenoid valve (SV-3) and the fourth solenoid valve (SV-4) are 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. 1 to perform a cooling operation.

More specifically, the primary-side refrigerant discharged from the primary-side compressor (11) passes through the primary-side four-way switching valve (12) and is divided into two parts. 15)
And the other flows into the second branch pipe (52). The primary refrigerant flowing through the main circuit (15) is supplied to the outdoor heat exchanger (HE
X6). In the outdoor heat exchanger (HEX6), the primary-side refrigerant condenses by performing heat exchange with the outside air. The condensed primary-side refrigerant passes through the receiver (13) and is heated (HEX3)
Flows to

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. The primary-side refrigerant that has released heat in the heating heat exchanger (HEX3) is divided into two parts, one of which flows directly through the main circuit (15) toward the main heat exchanger (HEX2), and the other flows into the first branch pipe ( 51).

If the amount of heating of the secondary refrigerant in the heating heat exchanger (HEX3) is insufficient, the primary compressor (1
1) Heated refrigerant (hot gas) heated heat exchanger (HEX3)
Directly to. Specifically, the fourth solenoid valve (SV-4) is opened, and the discharged refrigerant is sent through the sixth branch pipe (56).
In this case, the first solenoid valve (SV-1) is closed, the third solenoid valve (SV-3) is opened, and the refrigerant flowing out of the receiver (13) is heated by the third branch pipe (53). It is sent downstream of the exchanger (HEX3).

The primary refrigerant flowing into the second branch pipe (52) is introduced into the reheat heat exchanger (HEX7). In the reheat heat exchanger (HEX7), the primary refrigerant exchanges heat with the secondary refrigerant flowing through the first main liquid pipe (25) of the secondary circuit (20). By this heat exchange, the secondary-side refrigerant sent to the liquid-side communication pipe (27) is heated to a predetermined temperature. Reheat heat exchanger (HEX7)
The primary-side refrigerant that has radiated heat in the first branch pipe (51)
And flows toward the cooling heat exchanger (HEX4) together with the primary refrigerant diverted from the main circuit (15).

The primary refrigerant flowing to the cooling heat exchanger (HEX4) flows into the cooling heat exchanger (HEX4) after being depressurized by the second expansion valve (EV-2). In the cooling heat exchanger (HEX4), the primary refrigerant exchanges heat with the secondary refrigerant of the pump circuit (30).
By this heat exchange, the primary-side refrigerant evaporates and the secondary-side refrigerant condenses at the same time, and the cooling heat exchanger (HEX4) is maintained in a low pressure state. 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).

The primary refrigerant flowing out of the heating heat exchanger (HEX3) and flowing through the main circuit (15) toward the main heat exchanger (HEX2) is depressurized by the first expansion valve (EV-1). Flow into the main heat exchanger (HEX2). 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-side refrigerant evaporates and the secondary-side refrigerant is condensed at the same time, and cold energy is given to the secondary-side refrigerant. The primary refrigerant evaporated in the main heat exchanger (HEX2) is sucked into the primary compressor (11) through the primary four-way switching valve (12).

In the secondary circuit (20), a cold / hot transfer operation is performed. 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. In the secondary circuit (20), the secondary refrigerant circulates between the main heat exchanger (HEX2) and the indoor heat exchanger (HEX1) while changing its phase, and
The cold generated in the secondary circuit (10) is the indoor heat exchanger (HEX1)
Transported to

Specifically, the following description is based on the state where each of the solenoid valves (SV-P1, SV-V2, SV-P3) of the pump circuit (30) is in the following state. 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 first main liquid pipe (25) of the secondary circuit (20).

On the other hand, the second main tank (T2) communicates with the cooling heat exchanger (HEX4). As described above, the cooling heat exchanger (HEX4) is maintained at a low pressure by the condensation of the refrigerant. Accordingly, the gas refrigerant in the second main tank (T2) is sucked into the cooling heat exchanger (HEX4) through the gas recovery pipe (32), whereby the pressure in the second main tank (T2) is reduced. When the pressure in the second 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 arrow in FIG. 1, the liquid refrigerant in the second main liquid pipe (26) is sucked, and the secondary four-way switching valve (2
3), the liquid flows through the collecting liquid pipe (38) and the branch pipe (38b) of the collecting liquid pipe (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), which pressurizes the sub tank (ST). The liquid refrigerant is pushed out from the pressurized sub tank (ST). As shown by a broken arrow in FIG.
Flows through 4) and flows into the heat exchanger (HEX3) through the buffer tank (BT). And heating heat exchanger (HEX3)
Is maintained at a high pressure by evaporating the liquid refrigerant sent through the liquid recovery pipe (34).

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) communicates with the cooling heat exchanger (HEX4), and the pressure in the sub tank (ST) is reduced. In the sub-tank (ST) whose pressure has been reduced, a part of the refrigerant flowing through the extruding liquid pipe (37) is recovered 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 sub-tank (ST) is repeatedly pressurized and depressurized as described above to supply the liquid refrigerant to the heating heat exchanger (HEX3).

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

Specifically, the liquid refrigerant (secondary refrigerant) pushed out of the first main tank (T1) is supplied to the first main liquid pipe (2).
5) Through the indoor heat exchanger (HEX) of each indoor unit (22)
Sent to 1). At that time, the liquid refrigerant flowing through the first main liquid pipe (25) is heated by exchanging heat with the primary refrigerant in the reheat heat exchanger (HEX7). In this reheat heat exchanger (HEX7), the secondary-side refrigerant is heated to a temperature slightly higher than the dew point temperature of the air around the liquid-side communication pipe (27). That is, the liquid refrigerant from the first main tank (T1) flows into the liquid-side communication pipe (27) after being heated to a predetermined temperature in the reheat heat exchanger (HEX7). Therefore, dew condensation does not occur outside the liquid side communication pipe (27).

The liquid refrigerant distributed to each indoor unit (22) through the liquid side communication pipe (27) is decompressed by the indoor expansion valve (EV) and then introduced into the indoor heat exchanger (HEX1). 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. Each indoor heat exchanger (HEX
The refrigerant evaporated in 1) flows to the main heat exchanger (HEX2) through the main gas pipe (24).

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 radiated by the main heat exchanger (HEX2)
It flows through the main liquid pipe (26) and is introduced into the gas-liquid separator (71).

In the gas-liquid separator (71), liquid refrigerant accumulates in the lower part, and gas refrigerant accumulates in the upper part. That is, in the gas-liquid separator (71), the introduced secondary-side refrigerant is separated into a liquid refrigerant and a gas refrigerant. The liquid refrigerant accumulated in the lower part of the gas-liquid separator (71) flows out of the gas-liquid separator (71) and flows again through the second main liquid pipe (26). The liquid refrigerant (secondary refrigerant) is collected in the second main tank (T2) through the collection liquid pipe (38).

On the other hand, the gas refrigerant accumulated in the upper part of the gas-liquid separator (71) passes through the gas return pipe (72) to the main heat exchanger (HE).
X2). That is, the gas refrigerant separated by the gas-liquid separator (71) is introduced into the main heat exchanger (HEX2) together with the secondary refrigerant (gas refrigerant) from the indoor heat exchanger (HEX1), and is again returned to the primary side. Performs heat exchange with the refrigerant.

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 solenoid valve (SV-P1, SV-P2, S) of the main tank (T1, T2) is opened and closed at its own timing to open and close the pressure reducing solenoid valve (SV-V3).
V-V1 and SV-V2) are performed regardless of opening and closing.

<< 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 the broken line in FIG. 2, and the third solenoid valve (SV-3) and the fourth solenoid valve (12) are switched. SV-4) is opened, and the first expansion valve (EV-1), the second expansion valve (EV-2), and the motor-operated valve (EV-F) 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 indicated by a dashed-dotted arrow in FIG. 2, and a heat pump operation is performed.

Specifically, the primary-side refrigerant discharged from the primary-side compressor (11) is divided into two parts, one of which is directed to the main heat exchanger (HEX2) without changing the main circuit (15). The other flows into the sixth branch pipe (56).

The primary-side refrigerant flowing to the main heat exchanger (HEX2) passes through the primary-side four-way switching valve (12) and is connected to the main heat exchanger (HEX2).
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-side refrigerant condensed in the main heat exchanger (HEX2) flows into the fifth branch pipe (55)
Through the receiver (13). The primary refrigerant flowing out of the receiver (13) returns to the main circuit (15) after flowing through the third branch pipe (53).

[0098] The primary refrigerant flowing into the sixth branch pipe (56) is introduced into the heating heat exchanger (HEX3). 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 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. Heating heat exchanger (HEX
The primary-side refrigerant condensed in 3) merges with the primary-side refrigerant from the third branch pipe (53) and flows through the main circuit (15). The merged primary-side refrigerant is then split into two parts, one of which is directed to the outdoor heat exchanger (HEX6) as it is in the main circuit (1).
5), and the other flows into 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 fourth branch pipe (54) to be connected to the outdoor heat exchanger (HEX6). 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-side refrigerant flowing into the first branch pipe (51) flows into the first branch pipe (51), and then one of the primary refrigerant flows through the first branch pipe (51) toward the cooling heat exchanger (HEX4). The other flows into the second branch pipe (52).

The primary refrigerant flowing to the cooling heat exchanger (HEX4) flows into the cooling heat exchanger (HEX4) after being depressurized by the second expansion valve (EV-2). In the cooling heat exchanger (HEX4), the primary refrigerant exchanges heat with the secondary refrigerant of the pump circuit (30).
By this heat exchange, the primary-side refrigerant evaporates and the secondary-side refrigerant condenses at the same time, and the cooling heat exchanger (HEX4) is maintained in a low pressure state. The primary-side refrigerant evaporated in the cooling heat exchanger (HEX4) flows again through the first branch pipe (51), and flows through the primary-side compressor (1).
Inhaled in 1).

The primary-side refrigerant flowing through the second branch pipe (52) is depressurized by the electric valve (EV-F) and then reheated by the reheat heat exchanger (HE).
X7). In the reheat heat exchanger (HEX7), the primary refrigerant flows through the first main liquid pipe (25) of the secondary circuit (20).
Exchanges heat with the secondary refrigerant. By this heat exchange, the secondary refrigerant flowing through the first main liquid pipe (25) and being sucked into the pump circuit (30) is cooled, and the secondary refrigerant is maintained in the liquid phase.
That is, during the heating operation, the reheat heat exchanger (HEX7) functions as a heat exchanger in front of the tank. Reheat heat exchanger (HEX
The primary refrigerant evaporated in 7) is returned to the second branch pipe (52).
Is drawn into the primary compressor (11).

In the secondary circuit (20), a thermal transfer operation is performed. 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 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. 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).

The operation of the pump circuit (30) is the same as during the cooling operation. 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 heat is transferred to the indoor heat exchanger (HEX1).

Specifically, one main tank (T1, T2)
The liquid refrigerant (secondary refrigerant) pushed out from the second passage passes through the liquid pipe for extrusion (37) and the four-way switching valve on the secondary side (23), and passes through the second refrigerant.
It is sent out to the main liquid pipe (26). The secondary refrigerant flowing through the second main liquid pipe (26) passes through the gas-liquid separator (71) and is introduced into the main heat exchanger (HEX2). In the main heat exchanger (HEX2), the secondary refrigerant exchanges heat with the primary refrigerant of the primary circuit (10), and 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 first main liquid pipe (25) through the indoor expansion valve (EV). The secondary refrigerant flowing through the first main liquid pipe (25) is:
It is introduced into the reheat heat exchanger (HEX7) and cooled. This cooling increases the degree of supercooling of the secondary refrigerant, and the secondary refrigerant is maintained in the liquid phase while the secondary four-way switching valve (23)
Then, the liquid is recovered to the other main tank (T1, T2) through the recovery liquid pipe (38).

According to the first embodiment, the gas refrigerant is separated from the secondary refrigerant by the gas-liquid separator (71) during the cooling operation, and the gas refrigerant is discharged from the main heat exchanger (HEX2). Only the liquid refrigerant of the secondary-side refrigerant can be sent to the main tanks (T1, T2) of the pump circuit (30). For this reason, it is possible to reliably apply the circulating drive force to the secondary refrigerant by the pump circuit (30), and to secure the circulation amount of the secondary refrigerant in the secondary circuit (20) to perform the cooling operation. It can be done reliably.

According to the first embodiment, the gas refrigerant separated in the gas-liquid separator (71) is supplied to the main heat exchanger (HEX2).
To the main heat exchanger (HEX2)
It is done in. Therefore, there is no need to newly provide a heat exchanger for condensing the separated gas refrigerant,
The configuration of the pump circuit (30) can be kept simple and an increase in manufacturing cost can be avoided.

Here, it is conceivable to use a cooling heat exchanger (HEX4) to condense the gas refrigerant separated by the gas-liquid separator (71). If the gas refrigerant thus separated is treated in the cooling heat exchanger (HEX4), it is not necessary to add a heat exchanger for condensing the gas refrigerant, and the same effect as that of the first embodiment can be obtained. Seems like

However, in this case, the cooling heat exchanger (HEX4) must condense the gas refrigerant from the gas-liquid separator (71) in addition to the gas refrigerant sucked from the main tanks (T1, T2). No. Therefore, the capacity of the cooling heat exchanger (HEX4) is insufficient for the amount of gas refrigerant to be condensed, and a sufficient amount of gas refrigerant cannot be sucked from the main tanks (T1, T2). Then, the pressure in the main tanks (T1, T2) may be insufficiently reduced, and the recovery amount of the secondary refrigerant may be insufficient, so that the pump circuit (30) may not be able to exhibit a sufficient capacity. On the other hand, if the cooling heat exchanger (HEX4) is configured to reliably process both the gas refrigerant from the main tanks (T1, T2) and the gas refrigerant from the gas-liquid separator (71), There is a problem that the heat exchanger (HEX4) becomes larger and the manufacturing cost also increases.

On the other hand, in the first embodiment, the gas refrigerant separated by the gas-liquid separator (71) is condensed by the main heat exchanger (HEX2). The main heat exchanger (HEX2) has a function of imparting cold or warm heat to the secondary-side refrigerant, and is configured to have a considerably larger capacity than the cooling heat exchanger (HEX4). Then, the amount of the gas refrigerant sent from the gas-liquid separator (71) is not so large in view of the capacity of the main heat exchanger (HEX2).

Therefore, even if the processing of the gas refrigerant separated by the gas-liquid separator (71) is performed by the main heat exchanger (HEX2), it is not necessary to use an even larger main heat exchanger (HEX2). Absent. Therefore, according to the first embodiment, a new heat exchanger is not provided in the pump circuit (30), and further, the specifications of the heat exchanger provided in the pump circuit (30) are not changed at all. The gas refrigerant separated by the gas-liquid separator (71) can be processed.

Further, as in Embodiment 1, the secondary refrigerant from the main heat exchanger (HEX2) is introduced into the gas-liquid separator (71), and the secondary refrigerant is converted into liquid refrigerant and gas refrigerant. If separated, the main heat exchanger (HEX2) can be downsized.

Explaining this point, when the gas-liquid separator (71) is not provided, the secondary flowing out of the main heat exchanger (HEX2) and flowing to the main tanks (T1, T2) of the pump circuit (30). In order to use only the liquid refrigerant as the side refrigerant, it is necessary to sufficiently supercool the secondary refrigerant in the main heat exchanger (HEX2). That is, in the main heat exchanger (HEX2), it is necessary not only to condense the secondary refrigerant but also to further cool the condensed secondary refrigerant. However, in general, the heat transfer coefficient at the time of changing the sensible heat of the liquid refrigerant is considerably lower than the heat transfer coefficient at the time of condensing the gas refrigerant. For this reason, if an attempt is made to increase the degree of supercooling of the secondary-side refrigerant, a large heat transfer area is required, which leads to an increase in the size of the main heat exchanger (HEX2).

On the other hand, when the gas-liquid separator (71) is provided as in the first embodiment, when the secondary refrigerant at the outlet of the main heat exchanger (HEX2) has little supercooling degree, Even when the degree of supercooling is not at all, or even in a gas-liquid two-phase state, the gas refrigerant is separated by the gas-liquid separator (71) and only the liquid refrigerant is supplied to the pump circuit (30). Can be sent to the main tank (T1, T2). Therefore, according to the first embodiment, it is not necessary to supercool the secondary refrigerant in the main heat exchanger (HEX2), and the main heat exchanger (HEX2) can be downsized.

In the first embodiment, the secondary circuit (2
The non-azeotropic mixed refrigerant is used as the secondary refrigerant of 0). In this case, if the gas-liquid separation means (70) is provided, the following effects can be obtained.

That is, in the pump circuit (30) according to the first embodiment, the gas refrigerant in the main tanks (T1, T2) is sucked into the cooling heat exchanger (HEX4) and condensed, whereby the main tank (T1, T1) is condensed. T2) is decompressed to collect the secondary refrigerant. On the other hand, when the secondary refrigerant, which is a non-azeotropic refrigerant mixture, evaporates, the low-boiling component having a relatively low boiling point among the components evaporates first. Therefore, the main tank (T1, T
The gas refrigerant sucked into the cooling heat exchanger (HEX4) from 2) has a higher proportion of low-boiling components than the non-azeotropic mixed refrigerant having a normal composition.

For this reason, if it is attempted to condense the gas refrigerant containing a large amount of low-boiling components from the main tanks (T1, T2) in the cooling heat exchanger (HEX4), the condensed amount decreases with the decrease in the condensing temperature of the gas refrigerant. Decreased, the main tank (T1, T2)
Becomes insufficient. In order to maintain the condensed amount of the gas refrigerant, the evaporation pressure of the primary refrigerant in the cooling heat exchanger (HEX4) must be reduced, which causes an increase in energy required for condensing the gas refrigerant.

On the other hand, in the first embodiment, the gas refrigerant is separated from the secondary refrigerant sucked into the main tanks (T1, T2) by providing the gas-liquid separation means (70). The composition of the separated gas refrigerant is high in low-boiling components. Therefore, the composition of the liquid refrigerant sent from the gas-liquid separator (71) to the main tanks (T1, T2) through the second main liquid pipe (26) is low in low boiling point components. For this reason, the secondary refrigerant present in the main tanks (T1, T2) has a low proportion of low-boiling components. as a result,
When depressurizing the main tanks (T1, T2), the cooling heat exchanger (H
The gas refrigerant sucked by EX4) also has a low proportion of low-boiling components. Therefore, even when a non-azeotropic mixed refrigerant is used as the secondary refrigerant, the energy required for condensing the gas refrigerant in the cooling heat exchanger (HEX4), specifically, in the primary circuit (10) An increase in power consumption of the primary compressor (11) can be avoided.

[0121]

[Embodiment 2] Embodiment 2 of the present invention is obtained by changing the arrangement of the gas-liquid separator (71) in Embodiment 1 described above. Here, parts different from the first embodiment will be described.

As shown in FIG. 3, the gas-liquid separator (71) according to the second embodiment is provided between the secondary four-way switching valve (23) and the suction side of the pump circuit (30). ing. Specifically,
The collection liquid pipe (38) of the pump circuit (30) is inserted inside the gas-liquid separator (71). Recovery liquid piping (38)
Has an opening end at the bottom of the gas-liquid separator (71).
The gas-liquid separator (71) is connected to a secondary four-way switching valve (23) via a connection pipe (73). This connection piping (73)
Has one end connected to the lower part of the gas-liquid separator (71), and the other end connected to the fourth port of the secondary four-way switching valve (23).

In the second embodiment, the secondary side four-way switching valve (23) is provided with an extrusion liquid pipe (37) and a first main liquid pipe (25).
And the connection pipe (73) and the second main liquid pipe (26) communicate with each other (the state shown by the solid line in FIG. 3), and the extrusion liquid pipe (37) and the second main liquid pipe (26) It is configured to be switched to a state where the communication and the connection pipe (73) communicate with the first main liquid pipe (25) (the state shown by the broken line in FIG. 3).

Further, the gas return pipe (7
2) is provided with a check valve (CV-11). This check valve (CV-11) is connected from the gas-liquid separator (71) to the main heat exchanger (HEX
Only the flow of gas refrigerant toward 2) is allowed. Therefore,
During the cooling operation, the gas refrigerant separated by the gas-liquid separator (71) is returned to the main heat exchanger (HEX2) through the gas return pipe (72). On the other hand, during the heating operation, the check valve (CV-11) of the gas return pipe (72) is shut off, and the main heat exchanger (HEX2)
The secondary-side refrigerant evaporated in the step does not flow back to the gas-liquid separator (71).

According to the second embodiment, the same effects as in the first embodiment can be obtained. In the second embodiment, the secondary refrigerant after exiting the main heat exchanger (HEX2) and passing through the secondary four-way switching valve (23) during the cooling operation is introduced into the gas-liquid separator (71). Then, the gas refrigerant is separated and sent to the main tanks (T1, T2) of the pump circuit (30). Therefore, even if the secondary refrigerant is flushed due to the pressure loss from the main heat exchanger (HEX2) to the gas-liquid separator (71), the gas refrigerant generated by the flush is transferred to the gas-liquid separator ( 71). Therefore, the secondary refrigerant flowing into the main tanks (T1, T2) can be more reliably maintained in the liquid phase.

[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 second embodiment.

[Explanation of symbols]

 (20) Secondary side circuit (heat transfer circuit) (23) Secondary side four-way switching valve (switching mechanism) (30) Pump circuit (transportation means) (70) Gas-liquid separation means (71) Gas-liquid separator ( (72) Gas return pipe (return pipe) (T1) First main tank (T2) 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 (low pressure section)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Sato 1304 Kanaokacho, Sakai-shi, Osaka Daikin Industries Kanaoka Plant, Sakai Plant Co., Ltd.

Claims (6)

[Claims] 1. A heat transfer circuit (20) having a main heat exchanger (HEX2) and a use-side heat exchanger (HEX1) filled with a transfer refrigerant, and a heat transfer circuit (20) for transferring the heat transfer circuit (20). A transfer means (30) for applying a circulating driving force to the refrigerant, wherein the transfer refrigerant circulates in the heat transfer circuit (20) while changing its phase and is applied to the transfer refrigerant by the main heat exchanger (HEX2) A heat transfer device that performs at least a cold transfer operation for transferring the cooled heat to the use side heat exchanger (HEX1), wherein a gas refrigerant is transferred from the transfer refrigerant that has exited the main heat exchanger (HEX2) during the cold transfer operation. A gas-liquid separating means (70) which is returned to the main heat exchanger (HEX2) in order to condense the separated gas refrigerant, and in a cold transfer operation, the transferring means (30) is provided by the gas-liquid separating means (70 ) Aspirates the transfer refrigerant from which the gas refrigerant has been removed and sends it out to the user-side heat exchanger (HEX1) Heat transfer apparatus. 2. The heat transfer device according to claim 1, wherein the gas-liquid separation means (70) includes a separation container (71) for separating the transfer refrigerant into a liquid refrigerant and a gas refrigerant, and the separation container (71). 7
A heat transfer device including a return pipe (72) for leading the gas refrigerant separated in 1) to the main heat exchanger (HEX2). 3. The heat transfer device according to claim 2, wherein the separation vessel (71) of the gas-liquid separation means (70) exchanges main heat in the refrigerant circulation direction during the cold heat transfer operation of the heat transfer circuit (20). Heat transfer device installed immediately after the vessel (HEX2). 4. The heat transfer device according to claim 2, wherein the transfer means (30) includes a switching mechanism (23) for reversing a circulation direction of the transfer refrigerant in the heat transfer circuit (20). The main heat exchanger (HE) is connected to the circuit (20) and reverses the direction of circulation of the transfer refrigerant during cold transfer operation.
X2) is configured to switch the warm transfer operation to transfer the warm heat imparted to the transfer refrigerant to the use side heat exchanger (HEX1) with the cold transfer operation, while the gas-liquid separation means (70) A heat transfer device provided between the suction side of the transfer means (30) and the switching mechanism (23). 5. The heat transfer device according to claim 1, wherein the transfer means (30) is connected to a heat transfer circuit (20) and stores a pair of tanks for storing a transfer refrigerant. T1, T2), a high-pressure section (HEX3) for supplying the evaporated gas refrigerant to the tank (T1) and pressurizing the tank (T1), and condensing the gas refrigerant sucked from the tank (T2) And a low-pressure section (HEX4) for depressurizing the tank (T2). Pressurizing one of the tanks (T1) to push out the transfer refrigerant from the tank (T1), and at the same time, A) a heat transfer device configured to perform an operation of reducing the pressure and sucking the transfer refrigerant into the tank (T2) to apply a circulation driving force to the transfer refrigerant. 6. The heat transfer device according to claim 1, wherein the transfer refrigerant is a non-azeotropic mixed refrigerant.