JP2019163866A - Refrigeration cycle device and hot water generating device including the same - Google Patents

Abstract

To provide a refrigeration cycle device improved in energy consumption efficiency in both operating conditions of low load and high load.SOLUTION: A refrigeration cycle device includes: a main-side refrigerant circuit 11 having a plurality of compression mechanisms (1a, 1b), a radiator 2, an economizer heat exchanger 3, and first decompression means 4; and an injection-side refrigerant circuit 12 branched from a part between the radiator 2 and the economizer heat exchanger 3, or a part between the economizer heat exchanger 3 and the fist decompression means 4, and having second decompression means 6 and the economizer heat exchanger 3, so that the refrigerant branched from the main-side refrigerant circuit 11 is decompressed by the second decompression means 6, then exchanges heat with the refrigerant flowing through the main-side refrigerant circuit 11 in the economizer heat exchanger 3, and is joined to the refrigerant between the plurality of compression mechanisms (1a, 1b). A pipe through which the refrigerant of the main-side refrigerant circuit 11 of the economizer heat exchanger 3 flows has the shape with a grooved inner face.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a refrigeration cycle apparatus.

  As this type of refrigeration cycle apparatus, using a two-stage compressor having a low-stage compression mechanism and a high-stage compression mechanism, one of the refrigerant branched from between the radiator and the economizer heat exchanger is supplied to the first decompression means. An economizer that achieves high performance by providing an injection circuit that communicates and heat-exchanges with one refrigerant after the other is depressurized by the second depressurization means and merges between the low-stage compressor mechanism and the high-stage compression mechanism A cycle proposal has been made.

  7 and 8 are a schematic perspective view and a channel cross-sectional view of the economizer heat exchanger 20 mounted in the economizer cycle (see, for example, Patent Document 1).

International Publication No. 2011/021636

  However, in the refrigeration cycle apparatus equipped with the economizer heat exchanger 20 having a multi-hole smooth flow path on the high pressure side as shown in FIGS. 7 and 8, the refrigeration cycle apparatus is operated under both low load and high load operating conditions. There was a problem that the energy-saving property would be reduced. The reason is described below.

  When heating / hot water supply operation is performed in the refrigeration cycle apparatus, it is desirable that the high stage discharge pressure be higher than a predetermined pressure. FIG. 9 shows the calculated relationship between the theoretical COP of the heating operation and the high stage discharge pressure under predetermined operating conditions (incoming water 22 ° C., outgoing hot water 30 ° C., outside air 12 ° C.).

  Here, the refrigerant used for the calculation is carbon dioxide. As can be seen from FIG. 9, in order to operate the COP at a high state, it is desirable that the high-stage discharge pressure be set to a predetermined pressure or higher. As shown in FIGS. 10 (a) and 10 (b), since the temperature difference between water and the refrigerant cannot be obtained in the radiator when the high-stage discharge pressure becomes low, the enthalpy difference of the refrigerant is reduced, and the radiator This is because the heating capacity is greatly reduced.

  Here, in the heating operation of the refrigeration cycle apparatus, as shown in FIG. 11, the load changes greatly according to the outside air temperature, and it is necessary to increase the refrigerant circulation amount at the time of high load (for example, the outside air temperature −10 ° C.). There is. For this reason, the decompression means of the refrigeration cycle apparatus adjusts the high-stage discharge pressure so that it is close to a predetermined pressure at which the energy saving performance of the refrigeration cycle apparatus is maximized at the time of a high load at which the refrigerant circulation amount is maximum. And having a relatively large diameter (for example, a valve diameter of 0.5 mm or more) is selected.

  On the other hand, when the load is low (for example, the outside air temperature is 12 ° C.), the necessary refrigerant circulation amount is reduced, and the refrigerant circulation amount flowing through the first decompression means is extremely reduced. Therefore, in order to secure the amount of pressure reduction and maintain the high stage discharge pressure at a predetermined pressure or higher, it is necessary to throttle the first pressure reducing means to the vicinity of the fully closed state. However, since the operation of the refrigeration cycle becomes unstable, the temperature of the hot water at the user terminal is not stable.

  Therefore, the opening degree of the first pressure reducing means needs to be a certain level or more for stable operation. In this case, the high-stage discharge pressure can be maintained at a predetermined pressure or more because the pressure reduction amount is insufficient. However, the energy-saving property of the refrigeration cycle apparatus at the time of low load will have the subject that it will fall.

  In addition, when the load is high, the refrigerant flow rate on the intermediate pressure side of the economizer heat exchanger 20 may increase relative to the high pressure side in order to increase the refrigerant circulation amount. When the economizer high pressure side flow path 23 is a multi-hole smooth flow path not provided with heat transfer promoting means as in the prior art, the heat transfer coefficient of the high pressure side refrigerant is greatly reduced, and the heat resistance of the high pressure side refrigerant is reduced. Since the ratio is increased, the efficiency of the economizer heat exchanger 20 is decreased, and the operation efficiency of the device at the time of high load is also decreased.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a refrigeration cycle apparatus with improved energy consumption efficiency under both low load and high load operating conditions.

  In order to achieve the above object, a refrigeration cycle apparatus according to the present invention includes a compressor composed of a plurality of compression mechanisms, a radiator in which a use side heat medium is heated by refrigerant discharged from the compressor, an economizer heat exchanger, A first decompression means, a main-side refrigerant circuit formed by sequentially connecting evaporators, and between the radiator and the economizer heat exchanger, or the economizer heat exchanger and the first decompression means; In the economizer heat exchanger after the refrigerant branched from the main refrigerant circuit is depressurized by the second depressurization means. An injection-side refrigerant circuit that exchanges heat with the refrigerant flowing through the main-side refrigerant circuit and then merges with the refrigerant between the plurality of compression mechanisms. The heat exchanger has a high-pressure side refrigerant pipe through which a refrigerant flows in the main-side refrigerant circuit, and an injection pipe through which a refrigerant flows through the injection-side refrigerant circuit. It has a shape with an inner groove.

  Thereby, since the high-pressure side refrigerant pipe of the economizer heat exchanger becomes a resistance at a low load when the refrigerant circulation amount is small, while using the first decompression means corresponding to the high load when the refrigerant circulation amount is large, In a stable operation state, the amount of pressure reduction from the radiator outlet to the first pressure reducing means outlet can be increased.

  As a result, the high-stage discharge pressure can be maintained higher than the specified pressure even at low loads, and the enthalpy difference between the radiator inlet and outlet is increased, improving the energy-saving performance of the refrigeration cycle system at low loads. it can.

  In addition, when the load is high, the flow rate of refrigerant on the intermediate pressure side of the economizer heat exchanger is higher than that on the high pressure side. Even when the flow rate is low, the effect of promoting turbulence is generated, and the heat transfer coefficient of the refrigerant is increased.

  In addition, since the heat transfer area is increased and the thermal resistance of the high-pressure side refrigerant is reduced, the heat exchange efficiency of the economizer heat exchanger is improved and the energy saving performance of the refrigeration cycle apparatus at high load can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the refrigerating-cycle apparatus which improved energy consumption efficiency can be provided in the driving | running conditions of both the time of low load and high load.

Configuration diagram of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. (A) Perspective view of economizer heat exchanger in Embodiment 1 of the present invention (b) Top view of the economizer heat exchanger (A) AA sectional view of FIG. 2 (b) (b) C portion enlarged view of FIG. 3 (a) Pressure-enthalpy diagram (Ph diagram) under ideal conditions of the refrigeration cycle apparatus according to Embodiment 1 of the present invention The figure which shows the relationship between the opening degree of the pressure reduction means of the refrigeration cycle apparatus, and a flow rate characteristic (A) Schematic diagram of economizer heat exchanger according to another embodiment of the present invention (b) BB cross-sectional view of FIG. 6 (a) Schematic diagram of a conventional economizer heat exchanger Cross-sectional view of a conventional economizer heat exchanger Diagram showing the relationship between theoretical COP and high stage discharge pressure at low load (A) The figure which shows the relationship between the temperature of a radiator at the time of low load, and an enthalpy characteristic (b) The other figure which shows the relationship between the temperature of the radiator at the time of a low load, and an enthalpy characteristic The figure which shows the characteristic of the outside temperature of the refrigeration cycle device and the heating load

  In the first invention, a compressor composed of a plurality of compression mechanisms, a radiator in which the use side heat medium is heated by the refrigerant discharged from the compressor, an economizer heat exchanger, a first pressure reducing means, and an evaporator are sequentially provided. Branched from the main refrigerant circuit connected and formed, and between the radiator and the economizer heat exchanger, or between the economizer heat exchanger and the first decompression means, and the second decompression And a refrigerant flowing through the main refrigerant circuit in the economizer heat exchanger after the refrigerant branched from the main refrigerant circuit is depressurized by the second depressurizing means An injection-side refrigerant circuit that is heat-exchanged and then merges with the refrigerant between the plurality of compression mechanisms, and the economizer heat exchanger cools the main-side refrigerant circuit. A refrigeration cycle characterized in that it has a high-pressure side refrigerant pipe as a flow path through which the refrigerant flows, and an injection pipe as a flow path through which the refrigerant in the injection-side refrigerant circuit flows. Device.

  Thereby, since the high pressure side refrigerant pipe of the economizer heat exchanger becomes a resistance at a low load when the refrigerant circulation amount is small, while using the first decompression means corresponding to the high load when the refrigerant circulation amount is large, In a stable operation state, the amount of pressure reduction from the radiator outlet to the first pressure reducing means outlet can be increased.

  As a result, the high-stage discharge pressure can be maintained higher than the specified pressure even at low loads, and the enthalpy difference between the radiator inlet and outlet is increased, improving the energy-saving performance of the refrigeration cycle system at low loads. It has the effect of being able to

  In addition, when the load is high, the flow rate of refrigerant on the intermediate pressure side of the economizer heat exchanger is higher than that on the high pressure side. Even when the flow rate is low, the effect of promoting turbulence is generated, and the heat transfer coefficient of the refrigerant is increased.

  In addition, since the heat transfer area is increased and the thermal resistance of the high-pressure refrigerant is reduced, the heat exchange efficiency of the economizer heat exchanger is improved and the intermediate pressure is increased. As a result, the compression ratio on the high stage side with a large amount of refrigerant circulation is reduced, and the power of the compressor can be reduced. Thus, the energy saving performance of the refrigeration cycle apparatus at the time of high load can be improved.

  According to a second aspect of the invention, in particular, in the first aspect of the invention, the pipe center position in the refrigerant flow direction of the high-pressure side refrigerant pipe is positioned vertically below the pipe center position of the injection pipe in the refrigerant flow direction. Further, the economizer heat exchanger is formed, and the refrigerant flowing through the injection pipe is in a gas-liquid two-layer state.

  Thereby, gravity acts on the gas-liquid two-layer refrigerant flowing through the injection pipe, and a liquid component having a high density is pushed near the heat transfer surface, so that the liquid component of the refrigerant is more easily heated. Therefore, since the heat exchange amount of the economizer heat exchanger increases and the intermediate pressure increases, there is an effect that the energy saving performance of the refrigeration cycle apparatus can be further improved.

  A third invention is characterized in that, in particular, in the first or second invention, the high-pressure side refrigerant pipe is disposed inward of the injection pipe.

  Thereby, since the low-temperature intermediate pressure refrigerant flows on the outer peripheral side of the economizer heat exchanger, the heat radiation loss in the economizer heat exchanger can be reduced. Therefore, since the heat exchange efficiency of the economizer heat exchanger is improved, the energy saving performance of the refrigeration cycle apparatus can be further improved.

  A fourth invention is characterized in that, in particular, in any one of the first to third inventions, the refrigerant is carbon dioxide.

  Thereby, by applying the carbon dioxide refrigerant to the multistage compression refrigeration cycle having the injection side refrigerant circuit, the refrigerant enthalpy difference at the time of heat absorption in the evaporator is greatly expanded as compared with the fluorocarbon refrigerant.

  Further, the refrigerant flow rate discharged from the high-stage compression mechanism of the multistage compression refrigeration cycle greatly increases the refrigerant flow rate flowing into the radiator due to the merge of the refrigerant from the injection side refrigerant circuit and the main side refrigerant circuit. .

  As a result, in addition to the effects of the first to third aspects of the invention, it is possible to provide a refrigeration cycle apparatus in which the heating capacity for heating is significantly improved as compared with the case of a chlorofluorocarbon refrigerant.

  5th invention is a warm water production | generation apparatus provided with the said 1st-4th invention with the said utilization side heat medium being water or antifreeze.

  Thereby, the warm water production | generation apparatus provided with the refrigerating-cycle apparatus which improved energy saving property can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a circuit configuration diagram of a hot water generating device including a refrigeration cycle apparatus 10 according to Embodiment 1 of the present invention.

  In FIG. 1, the refrigeration cycle apparatus includes a main-side refrigerant circuit 11, an injection-side refrigerant circuit 12, and a use-side heat medium circuit 13, and carbon dioxide, which is a natural refrigerant, is enclosed as a refrigerant.

  The main refrigerant circuit 11 includes a low-stage compression mechanism 1a, a high-stage compression mechanism 1b, and a two-stage compressor 1 composed of a plurality of compression mechanisms, a radiator 2, an economizer heat exchanger 3, a first decompression means 4, and an evaporator. 5 are connected in an annular shape with a refrigerant pipe in order, and the refrigerant circulates inside.

  In the evaporator 5, the refrigerant that absorbs heat from the outside air and is compressed to a high temperature and a high pressure by the two-stage compressor 1 circulates through the radiator 2 through the use-side heat medium circuit 13 including the circulation pump 15 and the heating terminal 14. Heated water and antifreeze liquid are heated (heat exchange) to generate hot water, which is used for heating and hot water supply.

  Further, the injection-side refrigerant circuit 12 is configured so that a part of the high-pressure refrigerant branched from the refrigerant branch point A between the radiator 2 and the economizer heat exchanger 3 is reduced to an intermediate pressure by the second decompression means 6. After the heat exchange with the refrigerant heading from the economizer heat exchanger 3 toward the first decompression means 4, the refrigerant is connected so as to join the refrigerant confluence B between the low-stage compression mechanism 1a and the high-stage compression mechanism 1b. Yes.

  FIG. 2A is a perspective view of the economizer heat exchanger according to Embodiment 1 of the present invention. FIG. 2B is a top view of the economizer heat exchanger. Fig.3 (a) is AA sectional drawing of FIG.2 (b). FIG.3 (b) is the C section enlarged view of Fig.3 (a).

  As shown in FIG. 3 (b), the high-pressure side refrigerant pipe 3a of the economizer heat exchanger 3 is an internally grooved pipe, and the outer surface of the high-pressure side refrigerant pipe 3a and the injection so that heat can be exchanged between the refrigerant flowing inside. A heat transfer surface is formed by joining or contacting the outer surface of the pipe 3b.

  Further, the pipe center position in the refrigerant flow direction of the high-pressure side refrigerant pipe 3a is arranged so as to be positioned vertically downward from the pipe center position of the injection pipe 3b in the refrigerant flow direction. Note that the intermediate pressure refrigerant flowing inside the injection pipe 3b is temporarily in a gas-liquid two-layer state.

  Hereinafter, the operation and action of the hot water generating apparatus including the refrigeration cycle apparatus 10 configured as described above will be described.

  FIG. 4 is a pressure-enthalpy diagram (Ph diagram) under ideal conditions of the refrigeration cycle apparatus according to Embodiment 1 of the present invention, points a to e shown in the diagram, and refrigerant branch store A. And the refrigerant | coolant branch point B respond | corresponds with what was attached | subjected to FIG. 1, respectively.

  During the heating operation for generating warm water, the high-temperature and high-pressure refrigerant (point a) discharged from the high-stage compression mechanism 1b of the two-stage compressor 1 exchanges heat with water in the radiator 2 to dissipate heat. The heated water circulates in the use-side heat medium circuit 13 and flows into a connected hot water storage tank or a heating terminal 14 such as a floor warmer, and is used for heating or hot water supply.

  The high-pressure refrigerant radiated by the radiator 2 branches into the main-side refrigerant circuit 11 and the injection-side refrigerant circuit 12 at the refrigerant branch point A, and the high-pressure refrigerant flowing through the main-side refrigerant circuit 11 is intermediated by the second decompression means 6. The intermediate-pressure refrigerant flowing through the injection-side refrigerant circuit 12 that has been depressurized to the pressure is exchanged with the economizer heat exchanger 3 to be further cooled (point b).

  As a result, the main-side refrigerant decompressed by the first decompression means 4 flows into the evaporator 5 in a low-temperature and low-pressure gas-liquid two-layer state (point c), absorbs heat from the atmosphere, and is thus a two-stage compressor 1. Are sucked into the low-stage compression mechanism 1a (point d).

  On the other hand, the injection-side refrigerant branched at the refrigerant branch point A is decompressed to the intermediate pressure by the second decompression means 6, and after exchanging heat with the main-side high-pressure refrigerant in the economizer heat exchanger 3 as described above. Next, the main refrigerant discharged from the low-stage compression mechanism 1 a of the two-stage compressor 1 joins (refrigerant merge point B) and is sucked into the high-stage compression mechanism 1 b of the two-stage compressor 1.

  For this reason, since the refrigerant pressure is higher on the suction side (point B) of the high-stage compression mechanism 1b than on the suction side (point d) of the low-stage compression mechanism 1a, the refrigerant density is high and the low-stage compression mechanism 1a is discharged. Since the refrigerant combined with the refrigerant is sucked, compressed and discharged, the flow rate of the refrigerant flowing into the radiator 2 is greatly increased, and the ability to heat the water that is the heat medium on the use side is greatly increased. It is done. By repeating this operation, the refrigeration cycle apparatus 10 performs a heating operation for generating hot water.

  The circulation amount of the refrigerant flowing through the main refrigerant circuit 11 and the injection refrigerant circuit 12 is adjusted by the rotational frequency of the two-stage compressor 1 and the decompression amounts of the first decompression means 4 and the second decompression means 6. be able to. The refrigeration cycle apparatus 10 is efficient while satisfying the load by adjusting the refrigerant circulation amount of the main-side refrigerant circuit 11 and the injection-side refrigerant circuit 12 according to conditions such as the outside air temperature, the load, and the incoming water temperature. You can drive.

  Here, according to Embodiment 1 of the present invention, as shown in FIG. 3 (b), the high-pressure side refrigerant tube 3a of the economizer heat exchanger 3 is an internally grooved tube, and the refrigerant of the high-pressure side refrigerant tube 3a. The pipe center position in the flow direction of the injection pipe 3b is disposed so as to be positioned vertically downward from the longitudinal section of the pipe center position in the refrigerant flow direction of the injection pipe 3b.

  Since the high pressure side refrigerant pipe 3a is an internally grooved pipe, the high pressure side refrigerant pipe 3a of the economizer heat exchanger 3 becomes a resistance at a low load where the refrigerant circulation amount is small. While using the first pressure reducing means 4 corresponding to the load, the amount of pressure reduction from the radiator 2 outlet to the first pressure reducing means 4 outlet can be increased in a stable operating state.

  As a result, the high-stage discharge pressure can be maintained higher than a predetermined pressure even when the load is low, and the enthalpy difference at the entrance and exit of the radiator 2 is increased. The effect that can be improved.

  On the other hand, when the load is high, the flow rate of refrigerant on the intermediate pressure side of the economizer heat exchanger 3 is larger than that on the high pressure side. Even when the flow rate of the flowing refrigerant is low, the effect of promoting turbulence occurs, and the heat transfer coefficient of the refrigerant increases. In addition, since the heat transfer area is enlarged and the thermal resistance of the high-pressure side refrigerant is reduced, the heat exchange efficiency of the economizer heat exchanger 3 is improved, and the energy saving performance of the refrigeration cycle apparatus 10 at high load can be improved. Play.

  Further, as shown in FIG. 3B, the pipe center position in the refrigerant flow direction of the high-pressure side refrigerant pipe 3a of the economizer heat exchanger 3 is vertically lower than the pipe center position in the refrigerant flow direction of the injection pipe 3b. By being arranged so as to be located on the side, gravity acts on the gas-liquid two-layer refrigerant flowing through the injection pipe 3b, and a liquid component having a high density is transferred to the heat transfer surface between the high-pressure side refrigerant pipe 3a and the injection pipe 3b. As a result, the liquid component of the refrigerant is more easily heated. Thereby, since the heat exchange amount of the economizer heat exchanger 3 is increased and the intermediate pressure is increased, the energy saving performance of the refrigeration cycle apparatus 10 can be further improved.

  Here, the first decompression unit 4 and the second decompression unit 6 are electric expansion valves with variable opening, and the amount of decompression can be arbitrarily adjusted. FIG. 5 shows an example of the opening degree-flow rate characteristic of the fully-closed pressure reducing means.

  As shown in FIG. 5, even when the opening-flow rate characteristic of the decompression means has an inflection point and the gradient of the opening-flow rate characteristic in the vicinity of the fully closed opening range is larger than the gradient of the stable opening range, the economizer Since the high-pressure side refrigerant pipe 3a of the heat exchanger 3 is an internally grooved pipe, the amount of reduced pressure from the outlet of the radiator 2 to the outlet of the first pressure reducing means 4 can be increased, so that the high stage side discharge It becomes easier to adjust the pressure in a stable opening range where the opening-flow rate characteristics are moderate. Thereby, since the stability of operation | movement of the refrigerating-cycle apparatus 10 increases, there exists an effect that the temperature of warm water becomes comparatively uniform and the comfort in a heating terminal etc. increases.

  As described above, the refrigeration cycle apparatus 10 equipped with the economizer heat exchanger 3 according to Embodiment 1 can improve energy saving performance under both low load and high load operating conditions.

  In the present embodiment, the compressor composed of a plurality of compression mechanisms is the two-stage compressor 1 in which the low-stage compression mechanism 1a and the high-stage compression mechanism 1b are in the same container (shell). The compression mechanism 1a and the high-stage compression mechanism 1b may be configured independently as two compressors.

  Hereinafter, the economizer heat exchanger 3 according to another embodiment will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the part similar to Embodiment 1, and the detailed description is abbreviate | omitted.

  FIG. 6A is a schematic diagram of an economizer heat exchanger according to another embodiment. FIG. 6B is a cross-sectional view taken along the line BB in FIG.

  The difference between the present embodiment and the economizer heat exchanger 3 of the first embodiment is that, as shown in FIG. 6 (b), the high-pressure side refrigerant pipe 3a is disposed inside the injection pipe 3b. It is a point.

  The point that the pipe center position in the refrigerant flow direction of the high-pressure side refrigerant pipe 3a is positioned to be vertically lower than the pipe center position in the refrigerant flow direction of the injection pipe 3b is the embodiment. Same as 1.

  The operation and effect will be described below.

  Under extremely low outside air temperature and high incoming water temperature conditions, a high-temperature refrigerant (for example, 65 ° C.) flows through the high-pressure side refrigerant pipe 3a, and a low-temperature gas-liquid two-layer state (for example, 20 ° C.) flows through the injection pipe 3b. Refrigerant may flow.

  As a result, the high-pressure side refrigerant pipe 3a in which the high-temperature refrigerant flows is covered with the injection pipe 3b in which the low-temperature intermediate-pressure gas-liquid two-layer refrigerant flows, so that the heat loss is reduced as the economizer heat exchanger 3. Can be reduced. Therefore, since the heat exchange efficiency of the economizer heat exchanger 3 is improved, the energy saving property of the refrigeration cycle apparatus 10 can be improved.

  Further, as shown in FIG. 6B, the pipe center position in the refrigerant flow direction of the high-pressure side refrigerant pipe 3a of the economizer heat exchanger 3 is vertically lower than the pipe center position of the injection pipe 3b in the refrigerant flow direction. By being arranged so as to be located on the side, gravity acts on the gas-liquid two-layer refrigerant flowing through the injection pipe 3b, and the liquid component having a high density is vertically below the high-pressure side refrigerant pipe 3a and the injection pipe 3b. The liquid component of the refrigerant is more easily heated. Thereby, since the heat exchange amount of the economizer heat exchanger 3 is increased and the intermediate pressure is increased, the energy saving performance of the refrigeration cycle apparatus 10 can be further improved.

  As described above, since the refrigeration cycle apparatus according to the present invention can improve the energy consumption efficiency of the refrigeration cycle, it is useful for refrigeration, air conditioning, hot water supply, heating equipment and the like using the refrigeration cycle apparatus.

DESCRIPTION OF SYMBOLS 1 Two-stage compressor 1a Low stage compression mechanism 1b High stage compression mechanism 2 Radiator 3 Economizer heat exchanger 3a High pressure side refrigerant pipe 3b Injection pipe 4 First decompression means 5 Evaporator 6 Second decompression means 10 Refrigeration cycle apparatus DESCRIPTION OF SYMBOLS 11 Main side refrigerant circuit 12 Injection side refrigerant circuit 13 Use side heat medium circuit 14 Heating terminal 15 Circulation pump

Claims (5)

A compressor composed of a plurality of compression mechanisms, a radiator in which the use side heat medium is heated by the refrigerant discharged from the compressor, an economizer heat exchanger, a first pressure reducing means, and an evaporator are sequentially connected. A main refrigerant circuit;
Branched between the radiator and the economizer heat exchanger, or between the economizer heat exchanger and the first pressure reducing means, and having a second pressure reducing means and the economizer heat exchanger, After the refrigerant branched from the main-side refrigerant circuit is depressurized by the second depressurization means, the economizer heat exchanger exchanges heat with the refrigerant flowing through the main-side refrigerant circuit, and then the plurality of compression mechanisms. An injection-side refrigerant circuit joined to the refrigerant between,
The economizer heat exchanger includes a high-pressure side refrigerant pipe through which a refrigerant of the main-side refrigerant circuit flows, and an injection pipe having a flow path through which the refrigerant of the injection-side refrigerant circuit flows. A refrigeration cycle apparatus having a shape with a tip. The economizer heat exchanger is formed so that a pipe center position in the refrigerant flow direction of the high-pressure side refrigerant pipe is positioned vertically below a pipe center position in the refrigerant flow direction of the injection pipe, The refrigeration cycle apparatus according to claim 1, wherein the refrigerant flowing through the injection pipe is in a gas-liquid two-layer state. The refrigeration cycle apparatus according to claim 1 or 2, wherein the high-pressure side refrigerant pipe is disposed inside the injection pipe. The refrigeration cycle apparatus according to claim 1, wherein the refrigerant is carbon dioxide. The said utilization side heat medium is a warm water production | generation apparatus provided with the refrigeration cycle apparatus of any one of Claims 1-4 by water or antifreeze.

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