JP6811379B2 - Refrigeration cycle equipment - Google Patents

Description

The present invention relates to a refrigeration cycle apparatus including an indoor unit and a compressor, and the compressor is provided with a mechanism for injecting an intermediate pressure refrigerant in the process of compressing and discharging the sucked refrigerant.

Conventionally, in a refrigeration cycle device, a gas-liquid separator and an injection pipe are provided in the refrigerant pipe portion which is an intermediate pressure, the injection pipe is communicated with the injection hole of the compressor, and the gas-liquid separator and the injection pipe are connected by a gas bypass pipe. An injection circuit has been proposed (see Patent Document 1).

FIG. 7 shows a configuration diagram of the refrigeration cycle apparatus described in Patent Document 1. In the configuration of the refrigeration cycle device, the throttle device 26a, the throttle device 26b, and the throttle device 27 form a refrigerant piping portion that serves as an intermediate pressure, and the injection piping 29 and the flow rate adjusting device 30 that adjusts the flow rate of the refrigerant flowing through the injection piping 29. And, the gas-liquid separator 31 arranged in the refrigerant pipe portion which becomes the intermediate pressure, the gas bypass pipe 32 connecting the injection pipe 29 and the gas-liquid separator 31, and the refrigerant flow rate flowing through the gas bypass pipe 32 are adjusted. The on-off valve 33 is provided, and the flow rate adjusting device 30 and the on-off valve 33 are opened when the compressor 23 is operated.

As a result, when the indoor unit is in heating operation, the gas phase refrigerant flows through the gas bypass pipe 32 through the on-off valve 33 and flows in from the injection hole of the compressor 23, thereby improving the operating efficiency of the refrigeration cycle device and the flow rate adjusting device. A gas-liquid two-phase state refrigerant flows through the injection pipe 29 through 30, and flows in through the injection holes of the compressor 23, so that an effect of suppressing an excessive rise in the temperature of the refrigerant discharged from the compressor 23 can be expected.

Japanese Unexamined Patent Publication No. 2011-52883

However, in the configuration described in the prior art, the refrigerant flowing through the injection pipe during the heating operation of the indoor unit is in a gas-liquid two-phase state, and the confluence portion between the injection pipe and the gas bypass pipe and the branch portion of the injection pipe. Has a small pressure difference. From these facts, when the temperature of the refrigerant discharged from the compressor rises due to the low outside air temperature and the large compression ratio, and it is desired to increase the proportion of the liquid-phase refrigerant that has the effect of reducing the temperature, only the vapor-phase refrigerant is the injection piping. There is a problem that the flow of the liquid-phase refrigerant in the injection pipe is blocked by blowing through the inside, the liquid-phase refrigerant having a temperature reducing effect is not supplied to the compressor, and the temperature of the refrigerant discharged from the compressor rises excessively. It was. As a result, the motor winding temperature rises excessively and the motor efficiency decreases, or the refrigerating machine oil deteriorates and the lubrication performance decreases and the friction loss of the sliding part increases, resulting in the performance of the refrigeration cycle device. Decreases.

The present invention solves the above problems and prevents the amount of liquid phase refrigerant flowing into the compressor from becoming insufficient when the indoor unit is heated and the temperature of the refrigerant discharged from the compressor rises. It is an object of the present invention to provide a refrigeration cycle device.

In order to solve the above problems, the refrigeration cycle apparatus of the present invention includes a compressor, an indoor heat exchanger, a first pressure regulator, a second pressure regulator, an outdoor heat exchanger, and an injection pipe, and includes a compressor. The indoor heat exchanger, the first pressure regulator, the second pressure regulator, and the outdoor heat exchanger are connected in order, and are arranged in the intermediate pressure refrigerant pipe connecting the first pressure regulator and the second pressure regulator. In a refrigeration cycle device in which one branch portion and a compressor section of a compressor are connected by an injection pipe, a gas-liquid separator is provided between the first pressure regulator and the second pressure regulator to form a gas-liquid separator. It is equipped with a gas bypass pipe that connects to the injection pipe and allows the gas refrigerant separated by the gas-liquid separator to flow, and is equipped with a flow rate adjusting device between the confluence and the first branch where the injection pipe and the gas bypass pipe merge. It is a refrigeration cycle apparatus, and the first branch portion is a refrigeration cycle apparatus characterized in that it is installed on the upper side in the vertical direction from the confluence portion.

As a result, the gas-liquid two-phase state refrigerant flowing from the first branch to the injection pipe flows smoothly due to gravity, so that only the gas-phase refrigerant does not blow through and moves downward in the vertical direction. It will flow smoothly to the arranged confluence in a gas-liquid two-phase state.

Further, the refrigerating cycle apparatus of the present invention is provided with a rising pipe between the first branch portion and the outdoor unit connection portion, and exchanges heat with a low-pressure refrigerant between the rising pipe portion or the rising pipe portion and the outdoor unit connecting portion. It is a refrigeration cycle apparatus characterized in that a first supercooling heat exchanger is installed.

As a result, the refrigerant that has flowed into the rising pipe in a gas-liquid two-phase state with a dryness of 0.2 to 0.4 is dissipated to the low-temperature refrigerant in the first supercooling heat exchanger, and the dryness is 0.2 or less. Become.

When the gas-liquid two-phase state with a dryness of 0.2 to 0.4 flows through the rising pipe, the flow mode becomes a cyclic flow, so that the gas-phase refrigerant blows through and the liquid-phase refrigerant rises and stays inside the pipe. However, since the dryness becomes 0.2 or less in the first supercooling heat exchanger and flows through the rising pipe, the flow mode becomes a churn flow and gas and liquid are mixed and flow, so the liquid flows in the first branch part. The phase refrigerant is stably supplied.

Further, the refrigeration cycle apparatus of the present invention is a refrigeration cycle apparatus characterized in that a second supercooling heat exchanger that exchanges heat with a low-pressure refrigerant is installed between the first branch portion and the flow rate adjusting valve. ..

As a result, the refrigerant that has flowed into the injection pipe from the first branch portion in a gas-liquid two-phase state dissipates heat to the low-temperature refrigerant in the second supercooling heat exchanger and becomes a supercooled liquid state. When flowing through the flow control device in a gas-liquid two-phase state with a dryness of 0.1 or less, the state change is likely to occur between the saturated liquid state and the gas-liquid two-phase state due to load fluctuations in indoor air conditioning operation, and the liquid single phase. Due to the volume expansion when changing from gas to liquid two-phase, the flow rate of the refrigerant flowing through the flow rate regulator suddenly drops, but the second supercooling heat exchanger dissipates heat and the refrigerant flows into an overcooled state. The flow rate of the liquid phase refrigerant flowing through the flow rate adjusting device is stable without a sudden decrease in the flow rate.

In the refrigeration cycle device of the present invention, when the indoor unit is heated and the refrigerant in the gas-liquid two-phase state decompressed to the intermediate pressure by the first pressure regulating valve flows into the injection pipe from the first branch, the gas-liquid Since it reaches the confluence in a two-phase state and flows to the compressor's compressor together with the gas-phase refrigerant that flows from the gas bypass pipe into the injection pipe, the liquid-phase refrigerant with a large cooling effect is sufficiently supplied to the compressor's compressor. Therefore, it is possible to suppress an excessive rise in the temperature of the refrigerant discharged from the compressor.

Configuration diagram of the refrigeration cycle device according to the first embodiment of the present invention. Elevation view of the injection circuit according to the first embodiment of the present invention as viewed from the horizontal direction. Relationship between height difference and mass flow rate ratio of refrigerant in gas-liquid two-phase state Configuration diagram of the refrigeration cycle device according to the second embodiment of the present invention. Elevation view of the injection circuit according to the second embodiment of the present invention as viewed from the horizontal direction. Configuration diagram of the refrigeration cycle device according to the third embodiment of the present invention. Configuration diagram of the refrigeration cycle apparatus described in Patent Document 1.

The first invention includes a compressor, an indoor heat exchanger, a first pressure regulator, a second pressure regulator, an outdoor heat exchanger, and an injection pipe, and includes a compressor, an indoor heat exchanger, and a first pressure regulator. The second pressure regulator and the outdoor heat exchanger are connected in order, and the first branch and the compressor compressor arranged in the intermediate pressure refrigerant pipe connecting the first pressure regulator and the second pressure regulator. Is provided with a gas-liquid separator between the first pressure regulator and the second pressure regulator in the refrigeration cycle device connected by the injection pipe, and the gas-liquid separator and the injection pipe are connected to the gas-liquid separator. It is equipped with a gas bypass pipe through which the gas refrigerant separated in is flowed, and is equipped with a flow rate adjusting device between the confluence part where the injection pipe and the gas bypass pipe merge and the first branch part, and the first branch part is from the confluence part. It is a refrigeration cycle device characterized by being installed on the upper side in the vertical direction.

As a result, in the gas-liquid two-phase state refrigerant flowing from the first branch to the injection pipe, the flow of the liquid-phase refrigerant is blocked and only the gas-phase refrigerant does not blow through, and the high-density liquid-phase refrigerant is moved downward in the vertical direction by gravity. It will flow smoothly to the confluence located on the side in a gas-liquid two-phase state.

Therefore, the refrigerating cycle apparatus of the present invention remains in the gas-liquid two-phase state when the refrigerant in the gas-liquid two-phase state decompressed to the intermediate pressure by the first pressure regulator flows into the injection pipe from the first branch portion. Since the liquid phase refrigerant having a large cooling effect is sufficiently supplied to the confluence portion and the compression portion of the compressor, it is possible to suppress an excessive rise in the temperature of the refrigerant discharged from the compressor.

According to the second invention, in the refrigeration cycle apparatus according to the first invention, a rising pipe is provided between the first branch portion and the outdoor unit connecting portion, and the rising piping portion or the rising piping portion and the outdoor unit connecting portion are provided. It is a refrigeration cycle apparatus characterized in that a first supercooling heat exchanger that exchanges heat with a low-pressure refrigerant is installed between them.

As a result, the refrigerant that has flowed into the rising pipe in a gas-liquid two-phase state with a dryness of 0.2 to 0.4 is dissipated to the low-temperature refrigerant in the first supercooling heat exchanger, and the dryness is 0.2 or less. Become. When the gas-liquid two-phase state with a dryness of 0.2 to 0.4 flows through the rising pipe, the flow mode becomes a cyclic flow, so that the gas-phase refrigerant blows through and the liquid-phase refrigerant rises and stays inside the pipe. However, since the dryness becomes 0.2 or less in the first supercooling heat exchanger and flows through the rising pipe, the flow mode becomes a churn flow and gas and liquid are mixed and flow, so the liquid flows in the first branch part. The phase refrigerant is stably supplied.

Therefore, when the room temperature is high, the degree of supercooling cannot be obtained by the room heat exchanger, and the degree of dryness of the intermediate pressure refrigerant becomes high, the liquid phase refrigerant flows stably through the rising pipe portion, so that the compressor is compressed. A liquid-phase refrigerant having a large cooling effect is sufficiently supplied to the portion, and excessive rise in discharge temperature can be suppressed.

In the third invention, in the refrigeration cycle apparatus according to the first invention or the second invention, a second supercooling heat exchanger that exchanges heat with a low-pressure refrigerant is installed between the first branch portion and the flow control valve. It is a refrigeration cycle device characterized by the fact that it is used.

As a result, the refrigerant that has flowed into the injection pipe from the first branch portion in a gas-liquid two-phase state dissipates heat to the low-temperature refrigerant in the second supercooling heat exchanger and becomes a supercooled liquid state. When flowing through the flow control device in a gas-liquid two-phase state with a dryness of 0.1 or less, a state change is likely to occur between the saturated liquid state and the gas-liquid two-phase state due to load fluctuations in indoor air conditioning operation, and the liquid single phase. Due to the volume expansion when changing from gas to liquid two-phase, the flow rate of the refrigerant flowing through the flow rate regulator suddenly drops, but the second supercooling heat exchanger dissipates heat and the refrigerant flows into an overcooled state. The flow rate of the liquid phase refrigerant flowing through the flow rate adjusting device is stable without a sudden decrease in the flow rate.

Therefore, when the number of indoor units in operation decreases and the refrigerant decompressed to the intermediate pressure by the first pressure regulating valve flows into the injection pipe from the first branch in a gas-liquid two-phase state with a dryness of 0.1 or less. Since the state of the supercooled liquid is reached before passing through the flow rate adjusting device, the liquid phase refrigerant having a large cooling effect is sufficiently applied to the compression part of the compressor without a sudden decrease in the flow rate of the refrigerant flowing through the flow rate adjusting device. It is supplied and can suppress the excessive rise of the discharge temperature.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment.

(Embodiment 1)
FIG. 1 shows a configuration diagram of a refrigeration cycle device according to a first embodiment of the present invention.

The configuration of the refrigeration cycle device shown in FIG. 1 is such that one indoor air conditioning unit is connected to one outdoor air conditioning unit. The configuration of the refrigeration cycle device is not limited to that shown in FIG. For example, two or more outdoor air conditioning units and two or more indoor air conditioning units can be connected in parallel.

In the outdoor air conditioning unit 101, the injection compressor 111 is a compressor that compresses the refrigerant, and the refrigerant compressed by the injection compressor 111 is discharged to the discharge pipe 112. The outdoor heat exchanger 117 is a heat exchanger that exchanges heat between the ambient air and the air-conditioning refrigerant, and generally, a fin & tube type or microtube type heat exchanger is used.

In the outdoor air conditioning unit 101, the injection pipe 118 is a pipe through which the refrigerant flows when a part of the refrigerant is injected from the refrigeration cycle device into the injection compressor 111, and the flow rate adjusting device 119 measures the flow rate of the refrigerant flowing through the injection pipe 118. adjust. The intermediate pressure refrigerant pipe 115 is a pipe through which an intermediate pressure refrigerant flows, and the injection pipe 118 and the intermediate pressure refrigerant pipe 115 are branched at the first branch portion 120. The gas-liquid separator 121 is a pressure-resistant container for storing the liquid refrigerant and the gas refrigerant, and is connected to the intermediate pressure refrigerant pipe 115. The gas bypass pipe 122 is a pipe that connects the injection pipe 118 and the gas-liquid separator 121, and is connected to the injection pipe 118 by a merging portion 123. In FIG. 1, the first branch portion 120 is arranged between the first pressure regulator 114 and the gas-liquid separator 121, but is arranged between the second pressure regulator 116 and the gas-liquid separator 121. Is also good.

In the indoor air conditioning unit 102, the indoor heat exchanger 113 is a heat exchanger in which the ambient air and the refrigerant circulating in the refrigeration cycle device exchange heat, and the flow rate of the refrigerant flowing through the indoor heat exchanger 113 by the first pressure regulator 114. To adjust. As the indoor heat exchanger 113, a fin & tube type or microtube type heat exchanger is generally used.

FIG. 2 shows an elevational view of the injection circuit according to the first embodiment of the present invention as viewed from the horizontal direction.

In FIG. 2, the first branch portion 120 is installed on the upper side in the vertical direction with respect to the merging portion 123.

Next, the operation of the refrigeration cycle apparatus according to the present embodiment will be described.

In FIG. 1, the refrigerant compressed by the injection compressor 111 and having a high pressure is discharged from the injection compressor 111, exits from the outdoor air conditioning unit 101 via the discharge pipe 112, and then enters the indoor air conditioning unit 102. The refrigerant that has entered the indoor air conditioning unit 102 releases heat to the surrounding air by the indoor heat exchanger 113, condenses it, becomes a high-pressure supercooled liquid state, and then expands to an intermediate pressure by the first pressure regulator 114. It is in a gas-liquid two-phase state and exits from the indoor air conditioning unit 102.

The refrigerant that has returned from the indoor air conditioning unit 102 and then returned to the outdoor air conditioning unit 101 branches at the first branch 120, a part of the refrigerant flows into the injection pipe 118, and the remaining refrigerant flows into the gas-liquid separator 121. The gas-liquid two-phase state refrigerant flowing into the gas-liquid separator 121 is separated into a gas-phase refrigerant and a liquid-phase refrigerant, the gas-phase refrigerant flows into the gas bypass pipe 122, and the liquid-phase refrigerant flows from the gas-liquid separator 121. After exiting, it flows into the second pressure adjusting device 116. The refrigerant flowing into the second pressure regulator 116 is decompressed by the second pressure regulator 116, and then heat is taken from the surrounding air by the outdoor heat exchanger 117 and evaporated, resulting in a low-pressure superheated gas state. It is sucked into the injection compressor 111.

When the temperature of the refrigerant discharged from the injection compressor 111 becomes high, the flow rate adjusting device 119 is opened so that the refrigerant in a gas-liquid two-phase state flows into the injection pipe 118 and flows into the injection pipe 118. The resulting refrigerant passes through the open flow rate adjusting device 119, passes through the merging portion 123, merges with the gas phase refrigerant flowing through the gas bypass pipe 122, and is then supplied to the injection compressor 111.

Here, since the first branch portion 120 is installed on the upper side in the vertical direction with respect to the merging portion 123, the refrigerant flowing from the first branch portion 120 into the injection pipe 118 in a gas-liquid two-phase state reaches the merging portion 123. It flows downward in the vertical direction.

As described above, in the present embodiment, since the first branch portion 120 is installed on the upper side in the vertical direction with respect to the merging portion 123, the gas and liquid that has flowed into the injection pipe 118 from the first branch portion 120. Of the refrigerants in the phase state, the flow of the liquid-phase refrigerant is blocked by gravity, and only the gas-phase refrigerant does not blow through, and flows downward in the vertical direction to the confluence 123 in the gas-liquid two-phase state without interruption. Will be.

Therefore, in the refrigerating cycle apparatus of the present invention, when the refrigerant in the gas-liquid two-phase state decompressed to the intermediate pressure by the first pressure adjusting device 114 flows into the injection pipe 118 from the first branch portion 120, the gas-liquid two-phase state Since the liquid phase refrigerant having a large cooling effect is sufficiently supplied to the confluence portion 123 in this state and to the compression portion of the injection compressor 111, it is possible to suppress an excessive rise in the discharge temperature.

Assuming that the height difference between the first branch portion 120 and the confluence portion 123 is h, the height difference h is the gas-liquid two-phase state refrigerant flowing through the first branch portion 120 and the gas-phase refrigerant flowing through the gas bypass pipe 122. The mixing ratio affects the mixing ratio, and the mixing ratio of the refrigerant in the gas-liquid two-phase state affects the discharge temperature reducing effect ΔT of the refrigerant discharged from the injection compressor 111. At this time, the height difference h for obtaining the required amount of the discharge temperature reducing effect ΔT of the refrigerant discharged from the injection compressor 111 can be obtained as follows.

The density of the gas-liquid two-phase state refrigerant flowing through the first branch 120 is ρ', the flow velocity is v', the density of the gas-phase refrigerant flowing through the gas bypass pipe 122 is ρ', the flow velocity is v', and the confluence 123 When the density of the gas-liquid two-phase state refrigerant flowing from the injection compressor 111 is ρ, the flow velocity is v, and the kinetic acceleration is g, the refrigerant flowing through the first branch 120 based on the height of the confluence 123 The potential energy can be expressed as ρ'gh, the kinetic energy of the refrigerant flowing from the first branch 120 to the injection pipe 118 can be expressed as 0.5 × ρ'v'^ 2, and the kinetic energy of the refrigerant flowing through the gas bypass pipe 122 can be expressed. It can be expressed as 0.5 × ρ “v” ^ 2.

Considering that the two flows merge at the merging section 123, the gas-liquid two-phase state refrigerant flowing through the first branching section 120 is converted into kinetic energy at the merging section 123, so that the static pressure in front of the merging section 123 The gas phase refrigerant flowing through the gas bypass pipe 122 is also converted into kinetic energy at the merging portion 123, so that the static pressure in front of the merging portion 123 is lowered.

Here, if the amount of decrease in the static pressure of the refrigerant in the gas-liquid two-phase state is larger than the amount of decrease in the static pressure of the gas-phase refrigerant, the refrigerant in the gas-liquid two-phase state will not flow. It is necessary to increase the static pressure in front of the confluence portion 123 of the refrigerant in the gas-liquid two-phase state by supplementing with the position energy. That is, when the equation (1) is satisfied, the gas-liquid two-phase state refrigerant flows into the merging portion 123.
ρ'gh ≧ 0.5 × ρ'v' ^ 2-0.5 × ρ ”v” ^ 2 ・ ・ ・ Equation (1)

Here, assuming that the mass flow rate ratio of the refrigerant in the gas-liquid two-phase state at the merging portion 123 is m, v'becomes large and v'is small when the mass flow rate ratio m of the refrigerant in the gas-liquid two-phase state is large. It is clear that the height difference h becomes large.

FIG. 3 shows a relationship diagram between the height difference and the mass flow rate ratio of the refrigerant in the gas-liquid two-phase state. FIG. 3 is a graph showing the relationship between the height difference h and the mass flow rate ratio m of the refrigerant in the gas-liquid two-phase state based on the equation (1). The larger the mass flow rate ratio m of the refrigerant in the gas-liquid two-phase state where the cooling effect can be obtained, the larger the discharge temperature reduction effect ΔT. Therefore, the height difference h at which the required discharge temperature reduction effect ΔT can be obtained is obtained from FIG. It is preferable to install the first branch portion 120 and the confluence portion 123 so that the height difference is more than that.

At this time, the flow rate of the gas-liquid two-phase refrigerant flowing from the confluence unit 123 to the injection compressor 111 is calculated on the assumption that the volume flow rate is constant because it greatly depends on the volume flow rate due to the structure of the injection mechanism unit. ..

Further, the pressure loss in the pipe from the first branch portion 120 to the gas-liquid separator 121 may be set to ΔP, and the height difference h may be obtained by the equation (2) in consideration of the pressure loss ΔP.
ρ'gh ≧ 0.5 × ρ'v' ^ 2-0.5 × ρ ”v” ^ 2 + ΔP ・ ・ ・ Equation (2)

(Embodiment 2)
FIG. 4 shows a configuration diagram of the refrigeration cycle apparatus according to the second embodiment of the present invention.

In the configuration of the refrigeration cycle device of FIG. 4, the suction bypass pipe 126 is a refrigerant pipe that branches from between the first branch portion 120 and the outdoor unit connection portion 125 and connects to the suction pipe 128. The suction bypass flow rate adjusting device 127 is a device that adjusts the flow rate of the refrigerant flowing through the suction bypass pipe 126, and the first supercooling heat exchanger 124 is a heat exchanger capable of heat exchange with the refrigerant flowing through the injection pipe 118. Both the refrigerant flowing through the bypass pipe 126 and the refrigerant flowing through the injection pipe 118 flow through the partitioned flow paths, and in general, plate heat exchangers and double pipe heat exchangers are used. Used.

FIG. 5 shows an elevational view of the injection circuit according to the second embodiment of the present invention as viewed from the horizontal direction.

In FIG. 5, the rising pipe portion 129 is outdoors so that when the outdoor unit connection portion 125 is installed vertically below the merging portion 123, the first branch portion 120 is vertically above the merging portion 123. It is a refrigerant pipe provided between the machine connection portion 125 and the first branch portion 120. Further, the first supercooling heat exchanger 124 is installed between the rising pipe portion 129 or the rising piping portion 129 and the outdoor unit connecting portion 125.

Next, the operation of the refrigeration cycle apparatus according to the present embodiment will be described with reference to FIGS. 4 and 5.

The refrigerant compressed by the injection compressor 111 and having a high pressure is discharged from the injection compressor 111, exits from the outdoor air conditioning unit 101 via the discharge pipe 112, and then enters the indoor air conditioning unit 102. The refrigerant that has entered the indoor air conditioning unit 102 releases heat to the surrounding air by the indoor heat exchanger 113, condenses it, becomes a high-pressure supercooled liquid state, and then expands to an intermediate pressure by the first pressure regulator 114. It is in a gas-liquid two-phase state and exits from the indoor air conditioning unit 102.

A part of the refrigerant that has returned from the indoor air conditioning unit 102 and then returned to the outdoor air conditioning unit 101 flows into the suction bypass pipe 126, is depressurized by the suction bypass flow rate adjusting device 127, and then the first supercooling heat exchanger 124. It absorbs heat and becomes an overheated gas state, and merges with the refrigerant flowing through the suction pipe 128. The rest of the refrigerant returned to the outdoor air conditioning unit 101 flows into the rising pipe portion 129, dissipates heat in the first supercooling heat exchanger 124, and exits from the first supercooling heat exchanger 124. The refrigerant discharged from the first supercooling heat exchanger 124 branches at the first branch portion 120, a part of the refrigerant flows into the injection pipe 118, and the remaining refrigerant flows into the gas-liquid separator 121. The gas-liquid two-phase state refrigerant flowing into the gas-liquid separator 121 is separated into a gas-phase refrigerant and a liquid-phase refrigerant, the gas-phase refrigerant flows into the gas bypass pipe 122, and the liquid-phase refrigerant flows from the gas-liquid separator 121. After exiting, it flows into the second pressure adjusting device 116. The refrigerant flowing into the second pressure regulator 116 is decompressed by the second pressure regulator 116, and then heat is taken from the surrounding air by the outdoor heat exchanger 117 and evaporated, resulting in a low-pressure superheated gas state. It is sucked into the injection compressor 111.

When the temperature of the refrigerant discharged from the injection compressor 111 becomes high, the flow rate adjusting device 119 is opened so that the refrigerant in a gas-liquid two-phase state flows into the injection pipe 118 and flows into the injection pipe 118. The resulting refrigerant passes through the open flow rate adjusting device 119, passes through the merging portion 123, merges with the gas phase refrigerant flowing through the gas bypass pipe 122, and is then supplied to the injection compressor 111.

As described above, in the present embodiment, the rising piping section 129 is provided between the first branching section 120 and the outdoor unit connecting section 125, and the rising piping section 129 or the rising piping section 129 and the outdoor unit connecting section 125 are provided. Since the first supercooling heat exchanger 124 that exchanges heat with the refrigerant flowing through the suction bypass pipe 126 is installed between the two, the outdoor air conditioner unit 101 is in a gas-liquid two-phase state with a dryness of 0.2 to 0.4. The refrigerant returned to is radiated to the refrigerant flowing through the suction bypass pipe 126 in the first supercooling heat exchanger 124, and the degree of dryness becomes 0.2 or less.

When the gas-liquid two-phase state with a dryness of 0.2 to 0.4 is maintained and flows through the piping section 129, the flow mode becomes a circular flow, so that the gas-phase refrigerant sticks to the inner wall surface of the pipe. The liquid-phase refrigerant may rise and stay inside the piping section 129 by blowing through the space, but in the present embodiment, heat is dissipated by the first supercooling heat exchanger 124 and the dryness becomes 0.2 or less. By flowing through the rising pipe portion 129, the flow mode becomes a churn flow and the flow is a mixture of gas and liquid, so that the liquid phase refrigerant is stably supplied to the first branch portion 120.

Therefore, when the indoor temperature is high, the degree of supercooling cannot be obtained by the indoor heat exchanger 113, and the degree of dryness of the intermediate pressure refrigerant becomes high, the liquid phase refrigerant flows stably through the rising pipe portion 129, so that injection compression is performed. A liquid-phase refrigerant having a large cooling effect is sufficiently supplied to the compressed portion of the machine 111, and excessive rise in the discharge temperature can be suppressed.

(Embodiment 3)
FIG. 6 shows a configuration diagram of the refrigeration cycle apparatus according to the third embodiment of the present invention.

In the configuration of the refrigeration cycle device of FIG. 6, the second supercooling heat exchanger 130 is a heat exchanger that exchanges heat between the refrigerant branched from the first branch portion 120 and the refrigerant flowing through the suction pipe 128, and is the same as the flow rate adjusting device 119. It is installed between the first branch portion 120 and the first branch portion 120.

Next, the operation of the refrigeration cycle apparatus according to the present embodiment will be described.

In FIG. 6, the refrigerant compressed by the injection compressor 111 and having a high pressure is discharged from the injection compressor 111, exits from the outdoor air conditioning unit 101 via the discharge pipe 112, and then enters the indoor air conditioning unit 102. The refrigerant that has entered the indoor air conditioning unit 102 releases heat to the surrounding air by the indoor heat exchanger 113, condenses it, becomes a high-pressure supercooled liquid state, and then expands to an intermediate pressure by the first pressure regulator 114. It is in a gas-liquid two-phase state and exits from the indoor air conditioning unit 102.

The refrigerant returned to the outdoor air conditioning unit 101 branches at the first branch 120, a part of the refrigerant flows into the injection pipe 118, and the second supercooling heat exchanger 130 dissipates heat to the refrigerant flowing through the suction pipe 128, and then adjusts the flow rate. It merges with the refrigerant flowing through the gas bypass pipe 122 at the merging portion 123 via the device 119 and flows into the injection compressor 111. The rest of the refrigerant returned to the outdoor air conditioning unit 101 flows into the gas-liquid separator 121.

The gas-liquid two-phase state refrigerant flowing into the gas-liquid separator 121 is separated into a gas-phase refrigerant and a liquid-phase refrigerant, the gas-phase refrigerant flows into the gas bypass pipe 122, and the liquid-phase refrigerant flows from the gas-liquid separator 121. After exiting, it flows into the second pressure adjusting device 116. The refrigerant flowing into the second pressure regulator 116 is decompressed by the second pressure regulator 116, and then heat is taken from the surrounding air by the outdoor heat exchanger 117 and evaporated, resulting in a low-pressure overheated gas state. It is sucked into the injection compressor 111.

When the temperature of the refrigerant discharged from the injection compressor 111 becomes high, the flow rate adjusting device 119 is opened so that the refrigerant in a gas-liquid two-phase state flows into the injection pipe 118 and flows into the injection pipe 118. The resulting refrigerant passes through the open flow rate adjusting device 119, passes through the merging portion 123, merges with the gas phase refrigerant flowing through the gas bypass pipe 122, and is then supplied to the injection compressor 111.

As described above, in the present embodiment, since the second supercooling heat exchanger 130 is provided between the flow rate adjusting device 119 and the first branching portion 120, the outdoor air conditioning unit 101 is in a gas-liquid two-phase state. The refrigerant returned to the above heat is radiated to the refrigerant flowing through the suction pipe 128 in the second supercooling heat exchanger 130, and becomes a supercooled liquid state.

When flowing through the flow rate adjusting device 119 in a gas-liquid two-phase state with a dryness of 0.1 or less, which is close to the saturated liquid state, a state change occurs between the saturated liquid state and the gas-liquid two-phase state due to the load fluctuation of the indoor air conditioning operation. It is easy, and the volumetric expansion when changing from a liquid single phase to a gas-liquid two phase causes a sharp decrease in the flow rate of the refrigerant flowing through the flow rate adjusting device 119. However, in the present embodiment, since the second supercooling heat exchanger 130 dissipates heat to the refrigerant flowing through the suction pipe 128 and flows through the flow rate adjusting device 119 after becoming a supercooled liquid state, the sudden drop in the refrigerant flow rate does not occur. The flow rate is stable without being generated, and the liquid phase refrigerant is stably supplied to the first branch portion 120.

Therefore, when the dryness of the refrigerant flowing from the first branch 120 to the injection pipe 118 is small and the air conditioning load of the indoor unit fluctuates, a state change occurs between the saturated liquid state and the gas-liquid two-phase state. Since the liquid-phase refrigerant can be stably supplied to the merging portion 123, the liquid-phase refrigerant having a large cooling effect can be sufficiently supplied to the compression portion of the compressor, and excessive rise in the discharge temperature can be suppressed.

As described above, in the refrigerating cycle apparatus according to the present invention, when the refrigerant in the gas-liquid two-phase state decompressed to the intermediate pressure by the first pressure adjusting device 114 flows into the injection pipe 118 from the first branch portion 120, Since it is possible to prevent the flow of the liquid phase refrigerant from being blocked and the liquid phase refrigerant from being supplied to the injection compressor 111, the temperature of the discharge gas refrigerant of the compressor becomes excessive when the indoor unit operates in air conditioning. It can be suitably used as a device capable of operating with high efficiency by suppressing the increase in the motor winding temperature and the decrease in the motor efficiency.

101 Outdoor air conditioning unit 102 Indoor air conditioning unit 111 Injection compressor 112 Discharge pipe 113 Indoor heat exchanger 114 First pressure regulator 115 Intermediate pressure refrigerant pipe 116 Second pressure regulator 117 Outdoor heat exchanger 118 Injection pipe 119 Flow control device 120 1st branch 121 Gas-liquid separator 122 Gas bypass pipe 123 Confluence part 124 1st overcooling heat exchanger 125 Outdoor unit connection part 126 Suction bypass pipe 127 Suction bypass flow control device 128 Suction pipe 129 Rising pipe part 130 2nd excess Cooling heat exchanger

Claims (3)

It is provided with a compressor, an indoor heat exchanger, a first pressure regulator, a second pressure regulator, an outdoor heat exchanger, and an injection pipe, and includes the compressor, the indoor heat exchanger, the first pressure regulator, and the first. 2 In a refrigeration cycle device in which the pressure regulator and the outdoor heat exchanger are connected in a ring shape, a first branch portion is provided in an intermediate pressure refrigerant pipe connecting the first pressure regulator and the second pressure regulator. A gas-liquid separator is provided, the first branch portion and the compression portion of the compressor are connected by the injection pipe, and the gas-liquid separator is a gas bypass through which the gas refrigerant separated by the gas-liquid separator flows. A refrigeration cycle apparatus including a pipe, the gas bypass pipe is connected to the injection pipe at a confluence, and the first branch is installed vertically above the confluence. An outdoor unit connecting portion is provided between the first branch portion and the first pressure adjusting device, a rising piping portion is provided between the first branch portion and the outdoor unit connecting portion, and the rising piping portion and the above are described. The refrigeration cycle apparatus according to claim 1, wherein a first supercooling heat exchanger that exchanges heat with a low-pressure refrigerant is installed between the outdoor unit connection portion. A flow rate adjusting device is provided between the merging portion and the first branching portion, and a second overcooling heat exchanger that exchanges heat with a low-pressure refrigerant is installed between the first branching portion and the flow rate adjusting device. The refrigeration cycle apparatus according to claim 1 or 2, wherein the refrigeration cycle apparatus is provided.