JP4442068B2 - Refrigeration air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigeration air conditioner, and more particularly to a refrigeration air conditioner including a heat exchanger that performs heat exchange between a mainstream refrigerant and a bypass refrigerant and cools the mainstream refrigerant.
[0002]
[Prior art]
FIG. 9 is an explanatory diagram of the configuration of a conventional refrigeration apparatus disclosed in Japanese Patent Laid-Open No. 10-205898, in which 11 is a compressor, 12 is a condenser, 13 is an ejector, 14 is a gas-liquid separator, 15 is a refrigerant pump, Reference numeral 16 denotes an evaporator, and 17 a refrigerant pipe, which discloses a configuration in which a refrigerant represented by chlorofluorocarbon circulates in the refrigeration cycle 9. In this refrigeration apparatus, as described above, a compressor, a condenser, an ejector (also called an ejector), and a gas-liquid separator are connected in a ring shape, and further, a gas-liquid separator, a refrigerant pump, an evaporator, and an ejector are sequentially connected. It has a configuration. Since the performance of such a refrigeration apparatus is determined by how the pressure-enthalpy conversion is performed without loss in each component, reduction of energy loss in each component is an important point for technological development. In particular, reduction of energy loss in an ejector that recovers power by lowering the pressure of the refrigerant by adiabatic expansion is an important issue for improving the performance of the refrigeration apparatus.
[0003]
Hereinafter, the operation of the conventional refrigeration apparatus will be described with reference to the drawings. In such a refrigeration apparatus, first, refrigerant such as chlorofluorocarbon gas is compressed by the compressor 11 to be in a high temperature and high pressure state, and then introduced into the condenser 12 to be liquefied. Further, the refrigerant liquefied by the condenser 12 is introduced into the ejector 13 and is accelerated and depressurized while evaporating to be in a gas-liquid mixed state. The refrigerant in the gas-liquid mixed state is separated into a gas phase and a liquid phase by the gas-liquid separator 14, and the refrigerant vapor is led to the compressor 11 and circulates in the refrigeration cycle 9. Further, the refrigerant liquid in the gas-liquid separator 14 passes through the refrigerant pump 15 and is introduced into the evaporator 16 to be in a low temperature and low pressure state. The low-temperature and low-pressure refrigerant vapor that has flowed out of the evaporator 16 is integrated with the refrigerant that has been introduced from the condenser 12 into the ejector 13 and increased and reduced in pressure, and the pressure is recovered to a pressure equal to the suction pressure of the compressor 11. The refrigerant whose pressure has been recovered flows into the gas-liquid separator 14, and the refrigerant vapor returns to the compressor 11 to circulate through the refrigerant flow path. The refrigerant liquid is depressurized by the refrigerant pump 15 and vaporized by the evaporator 16, and the ejector 13. By returning to step 1, the bypass passage is circulated.
[0004]
As described above, in the conventional refrigeration apparatus, the refrigerant flowing out from the ejector 13 is gas-liquid separated by the gas-liquid separator 14, the refrigerant vapor is returned to the compressor 11, and the refrigerant liquid is supplied to the refrigerant pump 15 and the evaporator 16. Therefore, when the degree of supercooling of the refrigerant at the outlet of the condenser 12 is increased, the enthalpy of the refrigerant introduced into the ejector 13 is reduced, so that the increase in enthalpy due to the ejector 13 is reduced. Decreases. On the other hand, when the degree of supercooling of the refrigerant at the outlet of the condenser 12 is reduced, the enthalpy at the inlet of the ejector 13 increases. This increases the enthalpy at the outlet side of the evaporator 16, and the enthalpy at the inlet and outlet of the evaporator 16. It means that the difference decreases. Therefore, in order to obtain a predetermined cooling capacity, it is necessary to increase the flow rate of the refrigerant, resulting in a decrease in performance such as an increase in the amount of electric power input to the compressor. As described above, the conventional refrigeration apparatus has a conflicting problem that if the enthalpy of the refrigerant introduced into the ejector 13 is increased, the pressure loss after passing through the ejector 13 is increased, and if the enthalpy of the refrigerant is decreased, the effect of the ejector 13 is decreased. Therefore, efficient operation using an ejector was difficult.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of such a situation, and an object of the present invention is to provide a refrigeration air conditioner that efficiently recovers energy that has conventionally been lost in the flow rate control means and realizes highly efficient operation.
[0006]
[Means for Solving the Problems]
The refrigerating and air-conditioning apparatus according to the present invention includes a compressor, a condenser, a flow rate control means for reducing the pressure of the refrigerant, a main flow refrigerant route that connects the evaporator in order to circulate the refrigerant, and a refrigerant from the outlet side of the condenser. A bypass flow refrigerant route for branching the part, expanding the branched refrigerant by the expansion power recovery means and returning it to the inlet side of the compressor, and an inlet of the flow rate control means in the main flow refrigerant route by the refrigerant after expansion of the bypass flow refrigerant route And a heat exchanger for cooling the refrigerant on the side. Such a refrigerating and air-conditioning apparatus can have a configuration in which a second condenser and a second compressor are sequentially connected from the outlet side of the compressor to the inlet side of the condenser in the mainstream refrigerant route. A machine can be used.
[0007]
The refrigerating and air-conditioning apparatus according to the present invention includes a main flow refrigerant route in which a refrigerant is sequentially circulated through a compressor, a condenser, a first flow rate control means for reducing the pressure of the refrigerant, and an evaporator, and an outlet side of the condenser. A first part of the refrigerant is branched from the first, and the branched refrigerant is expanded by the expansion power recovery means, and then returned to the inlet side of the compressor through a gas-liquid separator that separates the expanded refrigerant into a gas phase and a liquid phase. A bypass flow refrigerant route, a second bypass flow refrigerant route that branches the refrigerant from the liquid phase side of the gas-liquid separator, expands the branched refrigerant by the second flow rate control means, and returns to the expansion power recovery means; A heat exchanger that cools the refrigerant on the inlet side of the flow rate control means in the main refrigerant route by the refrigerant after expansion of the second bypass refrigerant route. An ejector can be used as the expansion power recovery means.
[0008]
In such a refrigeration air conditioner, carbon dioxide can be used as the refrigerant.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
In the refrigeration air conditioner according to the present invention, for example, as shown in FIG. 1, a compressor 11, a condenser 12, a flow rate control means 41, and an evaporator 16 are sequentially connected in an annular manner through a refrigerant pipe. A hydrogen-based refrigerant circulates. In addition, a heat exchanger 40 is installed between the condenser 12 and the flow rate control means 41, and further, a bypass pipe 42 connects between the condenser 12 and the heat exchanger 40 and between the evaporator 16 and the compressor 11. It is connected. The expander 13 is disposed in the path of the bypass pipe 42, and the bypass pipe 42 is connected between the evaporator 16 and the compressor 11 through the heat exchanger 40 on the downstream side of the installation portion of the expander 13. Yes.
FIG. 2 is a pressure-enthalpy diagram for explaining the refrigeration cycle of the refrigeration air conditioner. Each point A to F shown in FIG. 2 is from A of the refrigeration air conditioner shown in FIG. Corresponding to each point of F, it represents the pressure-enthalpy state at each position.
[0010]
Hereinafter, the operation and effects of the refrigeration air conditioner will be described with reference to the pressure-enthalpy diagram shown in FIG. In such a refrigeration air conditioner, the refrigerant has the highest pressure and enthalpy at the outlet of the compressor 11 (point A in the figure). Next, the refrigerant compressed in the compressor 11 and brought into a high-temperature and high-pressure state is led to the condenser 12 to be condensed, and the enthalpy decreases with the pressure kept constant (point A → point B in the figure). A part of the refrigerant liquid at the outlet of the condenser 12 (point B in the figure) is adiabatically expanded by the expander 13 and changes to a low-temperature and low-pressure refrigerant two-phase state (point B → point F in the figure). This low-temperature and low-pressure refrigerant is vaporized by exchanging heat with the refrigerant liquid circulated from the condenser 12 to the flow rate control means 41 in the heat exchanger 40 and recovering the pressure to a pressure equal to the suction pressure of the compressor 11. Returning to FIG. 11 (F point → E point in the figure), it will be used as part of the power in the compressor 11. Further, the refrigerant remaining from the condenser 12 is cooled by exchanging heat with the refrigerant that has become low temperature and low pressure in the expander 13 in the heat exchanger 40 (point B → point C in the figure), and then the flow rate control. The refrigerant is decompressed by means 41 and becomes a low-temperature and low-pressure gas-liquid two-layer refrigerant (point C → point D in the figure), introduced into the evaporator 16, exchanges heat with air and vaporizes, and returns to the compressor 11 (in the figure). D point → E point). Then, the refrigerant is compressed by the compressor 11 to be in a high-temperature and high-pressure state (point E → point A in the figure) and circulates again through the above-described refrigeration cycle.
[0011]
As described above, in such a refrigeration air conditioner, the enthalpy of the refrigerant introduced into the flow control means can be reduced by supercooling the refrigerant circulating from the condenser to the flow control means by the heat exchanger. In other words, the energy lost at the time of pressure reduction in the flow control means is recovered by the refrigerant circulating in the compressor without passing through the evaporator, and high efficiency operation is possible by increasing the efficiency by reducing the energy loss in the flow control means. It becomes.
[0012]
In the above embodiment, the fluorocarbon or hydrocarbon refrigerant is used. However, the refrigerating and air-conditioning apparatus using carbon dioxide as the refrigerant has a large energy loss at the time of adiabatic expansion with respect to the refrigeration capacity. Is particularly prominent. Such an effect will be described with reference to the drawings. 3 is a pressure-enthalpy diagram in the adiabatic expansion process of carbon dioxide when the inlet temperature of the flow rate control means 41 is 35 ° C. and the outlet temperature is 10 ° C., and FIG. 4 is an inlet temperature of the flow rate control means 41 of 35 ° C. It is a pressure-enthalpy diagram in the process of adiabatic expansion of a fluorocarbon refrigerant at 10 ° C. 3 and 4, 50 and 60 are 35 ° C isotherms, 51 and 61 are isentropic wires, 52 and 62 are 10 ° C isotherms, 53 and 63 are energy losses, and 54 and 64 are refrigeration capacities. Yes. The energy loss 53 of carbon dioxide shown in FIG. 3 is larger than the energy loss 63 of the fluorocarbon refrigerant shown in FIG. 4 because carbon dioxide is in a critical state at 35 ° C. This is due to having unique properties different from typical refrigerants. On the other hand, the present invention is intended to reduce the energy loss caused by the flow rate control means, and therefore, when carbon dioxide having a large energy loss is used as a refrigerant, it is more effective than when a normal fluorocarbon refrigerant is used. It is.
[0013]
Embodiment 2
FIG. 5 is an example of a configuration explanatory diagram showing the configuration of the refrigerating and air-conditioning apparatus according to the present invention. The first compressor 11, the second condenser 45, the second compressor 46, the first condenser 12, and the first flow rate control means. 41 and the evaporator 16 are sequentially connected in an annular manner by a refrigerant pipe, so that a fluorocarbon or hydrocarbon refrigerant circulates. Further, a heat exchanger 40 is installed between the condenser 12 and the first flow rate control means 41, and further, a bypass pipe 42 is provided between the condenser 12 and the heat exchanger 40 and between the evaporator 16 and the compressor 11. Are connected. The expander 13 is installed in the bypass pipe 42, and the bypass pipe 42 is connected between the evaporator 16 and the compressor 11 through the heat exchanger 40 on the downstream side of the installation section of the expander 13.
FIG. 6 is a pressure-enthalpy diagram for explaining the refrigeration cycle of the refrigeration air conditioner. Each point from A ′ to H ′ shown in FIG. 6 indicates the refrigeration air conditioner shown in FIG. Corresponding to each point from A ′ to H ′, and represents the pressure-enthalpy state at each position.
[0014]
Hereinafter, the operation and effects of the refrigeration air conditioner will be described with reference to the pressure-enthalpy diagram shown in FIG. In such a refrigeration air conditioner, the refrigerant has the highest pressure and enthalpy at the outlet of the second compressor 46 (point A ′ in the figure). Next, the refrigerant compressed in the second compressor 46 and brought into a high-temperature and high-pressure state is led to the first condenser 12 and condensed, and the enthalpy decreases with the pressure kept constant (point A ′ → B in the figure). 'point). Part of the refrigerant liquid at the outlet of the first condenser 12 (point B ′ in the figure) is adiabatically expanded by the expander 13 and changes to a low-temperature and low-pressure refrigerant two-phase state (point B ′ → point H ′ in the figure). . This low-temperature and low-pressure refrigerant is vaporized by heat exchange with the refrigerant liquid circulated from the first condenser 12 to the flow rate control means 41 in the heat exchanger 40, and returns to the first compressor 11 (point H ′ in the figure → E ′ point), which is used as part of the power in the first compressor 11. The refrigerant introduced into the first compressor 11 is first compressed at the first stage (point E ′ → point F ′). The refrigerant subjected to the first-stage compression is then led to the second condenser 45 and condensed, and the enthalpy decreases with the pressure kept constant (point F ′ → G ′ in the figure). Further, the refrigerant that has exited the second condenser 45 is compressed in the second stage by the second compressor 46 (point G ′ → point A ′). Further, after the refrigerant remaining from the condenser 12 is cooled by exchanging heat with the refrigerant that has become low temperature and low pressure in the expander 13 in the heat exchanger 40 (B ′ point → C ′ point in the figure), The refrigerant is decompressed by the flow rate control means 41 to become a low-temperature and low-pressure refrigerant in a gas-liquid two-layer state (C ′ point → D ′ point in the figure), introduced into the evaporator 16 and vaporized by heat exchange with air or the like. Return to 11 (D ′ point → E ′ point in the figure). The refrigerant returned from the evaporator 16 to the first compressor 11 is the first compressor 11, the second condenser 45, and the second compressor 46, like the refrigerant circulating from the bypass pipe 42 to the first compressor 11. Passes through the high temperature and high pressure state (E ′ point → F ′ point → G ′ point → A ′ point in the figure), and the above-described refrigeration cycle is circulated again.
[0015]
As described above, in this refrigeration air-conditioning apparatus, the refrigerant compression process is performed in two stages, so that the energy lost during the low pressure in the flow rate control means is compressed without passing through the evaporator as in the first embodiment. The refrigerant is recovered by the refrigerant circulating in the machine, and the efficiency is improved by reducing the energy loss in the flow rate control means, and the power required for the compressor can be reduced, and the efficiency is further improved.
[0016]
In the above embodiment, the fluorocarbon type or hydrocarbon type refrigerant is described. However, when carbon dioxide is used as the refrigerant of the refrigerating and air-conditioning apparatus, the effect of the present invention is particularly similar to the first embodiment. Remarkable and preferred.
[0017]
Embodiment 3
FIG. 7 is an example of a configuration explanatory diagram showing the configuration of the refrigerating and air-conditioning apparatus according to the present invention, in which the compressor 11, the condenser 12, the first flow rate control means 41, and the evaporator 16 are sequentially connected in an annular manner through a refrigerant pipe. Fluorocarbon-based or hydrocarbon-based refrigerant circulates. Further, a heat exchanger 40 is installed between the condenser 12 and the first flow rate control means 41, and further, a first bypass pipe is provided between the condenser 12 and the heat exchanger 40 and between the evaporator 16 and the compressor 11. At 42, they are connected together. The first bypass pipe 42 is provided with the ejector 13 and the gas-liquid separator 14, and the gas-liquid separator 14, the second flow rate control means 43, the heat exchanger 40 and the ejector 13 are connected by the second bypass pipe 44. It is connected.
FIG. 8 is a pressure-enthalpy diagram for explaining the refrigeration cycle of the refrigeration air conditioner. Each point from a to k shown in FIG. 8 is a of the refrigeration air conditioner shown in FIG. To k, and represents the pressure-enthalpy state at each position.
[0018]
Hereinafter, the operation and effects of the refrigeration air conditioner will be described with reference to the pressure-enthalpy diagram shown in FIG. In such a refrigeration air conditioner, the refrigerant has the highest pressure and enthalpy at the outlet of the compressor 11 (point a in the figure). Next, the refrigerant compressed in the compressor 11 and brought into a high-temperature and high-pressure state is led to the condenser 12 to be condensed, and the enthalpy decreases with the pressure kept constant (point a → b in the figure). A part of the refrigerant liquid at the outlet of the condenser 12 (point b in the figure) is introduced into the first bypass pipe 42, reaches the ejector 13, and adiabatically expands in the ejector 13 to form a low-temperature and low-pressure refrigerant two-phase state. It changes (b point-> f point in the figure. Here, f point means the position immediately after the refrigerant in the ejector adiabatically expands). The refrigerant changed to the low-temperature and low-pressure two-phase state is mixed with the refrigerant introduced from the gas-liquid separator 14 through the second flow rate control means 43 and the heat exchanger 40 into the ejector 13, and the enthalpy and pressure increase ( In the figure, point f → g point → h point). The refrigerant having increased enthalpy and pressure is introduced into the gas-liquid separator 14 and separated into a gas phase and a liquid phase, and the refrigerant vapor circulates to the compressor 11 through the first bypass pipe 42 (in the drawing). h point → e point). Further, the refrigerant that has become a liquid phase in the gas-liquid separator 14 (point h → point i in the figure) passes through the second bypass pipe 44 and circulates to the second flow rate control means 43, and the pressure is reduced (in the figure). i point-> j point). The low-temperature and low-pressure refrigerant vapor exchanges heat with the refrigerant flowing from the condenser 12 to the first flow rate control means 41 in the heat exchanger 40 to increase the enthalpy (j point → k point in the figure). The refrigerant with the increased enthalpy is introduced into the ejector 13 through the second bypass pipe 44 and mixed with the high-pressure refrigerant introduced into the ejector 13 through the first bypass pipe 42 after leaving the condenser 12 as described above. The enthalpy is reduced and the pressure is increased (k point → g point → h point in the figure). Further, the refrigerant remaining from the condenser 12 is cooled by exchanging heat with the refrigerant having a low temperature and low pressure at the ejector 13 in the heat exchanger 40 (b point → c point in the figure), and then the flow rate control means. The refrigerant is depressurized at 41 to become a low-temperature and low-pressure gas-liquid two-phase refrigerant (from point c to point d in the figure), introduced into the evaporator 16, vaporized by heat exchange with air and the like, and returned to the compressor 11 (d in the figure). Point → e). Then, the refrigerant is compressed by the compressor 11 to be in a high temperature and high pressure state (point e → point a), and circulates again through the above-described refrigeration cycle.
[0019]
As described above, in such a refrigerating and air-conditioning apparatus, the refrigerant expanded by the ejector is separated by the gas-liquid separator, expanded again by the second flow rate control means, and the refrigerant is further reduced in temperature and pressure by the refrigerant. The refrigerant circulating in the flow rate control means can be subcooled more efficiently. That is, the energy lost in the flow control means is recovered by efficiently recovering the energy lost at the time of pressure reduction in the flow control means of the main refrigerant route with the lower temperature and low pressure refrigerant circulating in the second bypass flow refrigerant route. As a result, the efficiency of the refrigeration / air-conditioning apparatus can be efficiently operated as in the first and second embodiments.
[0020]
In the above embodiment, the fluorocarbon type or hydrocarbon type refrigerant is used. However, when carbon dioxide is used as the refrigerant of the refrigerating and air-conditioning apparatus, the effect of the present invention is the same as in the first and second embodiments. Is particularly prominent and preferred.
[0021]
【The invention's effect】
As described above, the refrigeration and air-conditioning apparatus according to the present invention includes a compressor, a condenser, a flow rate control means for reducing the pressure of the refrigerant, and a mainstream refrigerant route in which the refrigerant is continuously circulated through the evaporator, and a refrigerant from the outlet side of the condenser. A bypass flow refrigerant route for branching a part of the refrigerant and returning the branched refrigerant to the inlet side of the compressor by expansion power recovery means, and a flow rate control means in the main flow refrigerant route by the refrigerant after expansion of the bypass flow refrigerant route And a heat exchanger for cooling the refrigerant on the inlet side of the refrigerant, and the flow rate control means by supercooling the refrigerant supplied from the condenser to the flow rate control means with the refrigerant cooled by the expansion power recovery means Energy loss can be reduced, and a refrigerating and air-conditioning apparatus that operates with high efficiency can be realized. In the mainstream refrigerant route, when the second condenser and the second compressor are sequentially connected from the outlet side of the compressor to the inlet side of the condenser, the refrigerant compression process is performed in two stages. The power required is reduced and the efficiency is further improved. Furthermore, when an expander is used as the expansion power recovery means, the refrigerant can be expanded easily and efficiently, which is more preferable.
[0022]
Such a refrigerating and air-conditioning apparatus includes a main flow refrigerant route in which a refrigerant is sequentially circulated through a compressor, a condenser, a first flow rate control means for reducing the pressure of the refrigerant, and an evaporator, and a part of the refrigerant from the outlet side of the condenser. A first bypass flow refrigerant route that returns to the inlet side of the compressor through a gas-liquid separator that separates the expanded refrigerant into a gas phase and a liquid phase after the branched refrigerant is expanded by the expansion power recovery means A second bypass flow refrigerant route that branches the refrigerant from the liquid phase side of the gas-liquid separator, expands the branched refrigerant by the second flow rate control means, and returns to the expansion power recovery means; and second bypass flow refrigerant And a heat exchanger that cools the refrigerant on the inlet side of the flow rate control means in the mainstream refrigerant route with the refrigerant after expansion of the route, the refrigerant supplied from the condenser to the first flow rate control means is By flow control means By subcooling using the refrigerant whose temperature and pressure are reduced, the energy loss in the first flow rate control means is more efficiently reduced, and the enthalpy of the refrigerant is increased by using the energy recovered by cooling the refrigerant. Thus, by introducing it into the expansion power recovery means and returning it to the compressor through the gas-liquid separator, it is possible to improve the operating efficiency of the compressor, and it is possible to realize a refrigeration air conditioner that operates more efficiently. Further, when an ejector is used as the expansion power recovery means, the refrigerant can be expanded efficiently at low cost, which is preferable.
[0023]
Such a refrigerating and air-conditioning apparatus is preferable because the loss due to the flow rate control means can be effectively reduced when the refrigerant is carbon dioxide.
[Brief description of the drawings]
FIG. 1 is a configuration explanatory diagram showing a configuration of a refrigerating and air-conditioning apparatus according to the present invention.
FIG. 2 is a pressure-enthalpy diagram corresponding to the refrigeration air conditioner according to the present invention.
FIG. 3 is a pressure-enthalpy diagram when carbon dioxide is used as a refrigerant.
FIG. 4 is a pressure-enthalpy diagram when a fluorocarbon refrigerant is used.
FIG. 5 is a configuration explanatory diagram showing a configuration of a refrigeration air conditioner according to the present invention.
FIG. 6 is a pressure-enthalpy diagram corresponding to the refrigeration air conditioner according to the present invention.
FIG. 7 is a configuration explanatory diagram showing a configuration of a refrigeration air conditioner according to the present invention.
FIG. 8 is a pressure-enthalpy diagram corresponding to the refrigerating and air-conditioning apparatus according to the present invention.
FIG. 9 is an explanatory diagram showing a configuration of a conventional refrigeration apparatus.
[Explanation of symbols]
9 Refrigeration cycle, 11 Compressor, 12 Condenser, 13 Ejector,
14 gas-liquid separator, 15 refrigerant pump, 16 evaporator, 17 refrigerant piping,
40 heat exchanger, 41 flow rate control means (first flow rate control means),
42 bypass piping (first bypass piping), 43 second flow rate control means,
44 second bypass pipe, 45 second condenser, 46 second compressor,
50 isotherm of 35 ° C, 51 isentropic wire, 52 isotherm of 10 ° C,
53 energy loss, 54 freezing capacity, 60 isotherm at 35 ° C,
61 isentropic line, 62 10 ° C isotherm, 63 energy loss,
64 Freezing capacity.

Claims (3)

  A main flow refrigerant route in which a refrigerant is sequentially circulated through a compressor, a condenser, a first flow rate control means for reducing the pressure of the refrigerant, and an evaporator, and a part of the refrigerant is branched from the outlet side of the condenser. A first bypass flow refrigerant route that expands the expanded refrigerant by expansion power recovery means and then returns the expanded refrigerant to the inlet side of the compressor through a gas-liquid separator that separates the expanded refrigerant into a gas phase and a liquid phase; A second bypass flow refrigerant route that branches the refrigerant from the liquid phase side of the separator, expands the branched refrigerant by the second flow rate control means, and then returns to the expansion power recovery means; and the second bypass flow refrigerant route And a heat exchanger that cools the refrigerant on the inlet side of the flow rate control means in the mainstream refrigerant route by the expanded refrigerant.   The refrigerating and air-conditioning apparatus according to claim 1, wherein the expansion power recovery means is an ejector. Refrigeration and air conditioning apparatus according to any one of 2 to claim 1, wherein the refrigerant is carbon dioxide.

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