JP2003083620A - Refrigeration air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration / air-conditioning apparatus capable of reducing energy loss, which has conventionally been lost when a refrigerant is depressurized in a flow control means, and enabling highly efficient operation. SOLUTION: A bypass flow refrigerant route 42 in which a part of the refrigerant is branched at an outlet side of a condenser 12 and expanded by an expansion power recovery means 13 and circulated to an inlet side of a compressor 11.
The refrigerant at the inlet side of the flow control means 41 in the mainstream refrigerant route is supercooled by the expanded refrigerant, thereby reducing the energy loss of the flow control means 41 when the refrigerant is depressurized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating air conditioner, and more particularly to a refrigerating air conditioner having a heat exchanger for exchanging heat between a mainstream refrigerant and a bypass refrigerant to cool the mainstream refrigerant.

[0002]

2. Description of the Related Art FIG. 9 is a structural explanatory view of a conventional refrigerating apparatus disclosed in Japanese Unexamined Patent Publication No. 10-205898, 11 is a compressor, 12 is a condenser, 13 is an ejector, 14 is a gas-liquid separator, Reference numeral 15 is a refrigerant pump, 16 is an evaporator, 17 is a refrigerant pipe, and the refrigerant represented by Freon gas is the refrigeration cycle 9
This disclosure discloses a configuration that circulates. As described above, such a refrigeration system has a compressor, a condenser, an ejector (also called an ejector), and a gas-liquid separator connected in an annular shape,
Furthermore, the gas-liquid separator, the refrigerant pump, the evaporator, and the ejector are sequentially connected and connected. Since the performance of such a refrigeration system is determined by how pressure-enthalpy is converted in each constituent element without loss, reduction of energy loss in each constituent element is an important point in technological development. In particular, reduction of energy loss in the ejector that reduces the pressure of the refrigerant by adiabatic expansion to recover the power is an important issue for improving the performance of the refrigeration system.

The operation of the conventional refrigeration system will be described below with reference to the drawings. In such a refrigerating apparatus, a refrigerant such as CFC gas is first compressed by the compressor 11 into a high temperature and high pressure state, and then introduced into the condenser 12 and liquefied. Further, the refrigerant liquefied in the condenser 12 is introduced into the ejector 13 and is accelerated and decompressed while evaporating, and becomes 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, of which the refrigerant vapor is the compressor 11
And is circulated through 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 low-pressure refrigerant vapor that has flowed out of the evaporator 16 is integrated with the refrigerant that is introduced from the condenser 12 into the ejector 13 and is accelerated and decompressed, and the pressure is restored 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,
The refrigerant vapor circulates in the refrigerant flow path by returning to the compressor 11, and the refrigerant liquid is decompressed by the refrigerant pump 15 and vaporized in the evaporator 16 and returns to the ejector 13 to circulate in the bypass flow path.

As described above, in the conventional refrigeration system, the refrigerant flowing out of 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 pumped by the refrigerant pump 15 and. Since the refrigerant is introduced into the ejector 13 through the evaporator 16, if 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 decreases, so that the ejector 1
The effect of reducing the increase in enthalpy due to 3 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 rises, but this causes the enthalpy at the outlet side of the evaporator 16 to rise, and the enthalpy at the outlet and inlet of the evaporator 16 increases. It means that the difference is reduced. Therefore, it is necessary to increase the flow rate of the refrigerant in order to obtain a predetermined cooling capacity, which results in a decrease in performance such as an increase in the amount of electric power supplied to the compressor. As described above, in the conventional refrigeration system, if the enthalpy of the refrigerant introduced into the ejector 13 is increased, the pressure loss after passing through the ejector 13 increases, and if it is decreased, the effect of the ejector 13 decreases. Therefore, it was difficult to operate efficiently using the ejector.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a refrigerating and air-conditioning apparatus that efficiently recovers energy that was conventionally lost in the flow rate control means and realizes highly efficient operation. The purpose is to provide.

[0006]

A refrigerating and air-conditioning apparatus according to the present invention comprises a mainstream refrigerant route in which a compressor, a condenser, a flow rate control means for reducing the pressure of the refrigerant, and an evaporator are connected so that the refrigerant circulates sequentially. By bypassing a part of the refrigerant from the outlet side of the condenser, the branched refrigerant is expanded by the expansion power recovery means and returned to the inlet side of the compressor, and by the expanded refrigerant of the bypass flow refrigerant route. And a heat exchanger for cooling the refrigerant on the inlet side of the flow rate control means in the mainstream refrigerant route. Such a refrigerating and air-conditioning apparatus can be configured such that the second condenser and the second compressor are sequentially connected from the outlet side of the compressor to the inlet side of the condenser in the mainstream refrigerant route. Machine can be used.

In the refrigerating air-conditioning apparatus according to the present invention, the compressor, the condenser, the first flow rate controlling means for reducing the pressure of the refrigerant, and the evaporator are connected to the mainstream refrigerant route so that the refrigerant circulates sequentially, and the condenser. After branching a part of the refrigerant from the outlet side of the, and expanding the branched refrigerant by the expansion power recovery means, 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 first bypass flow refrigerant route to be returned and a second bypass flow refrigerant which is branched from the liquid phase side of the gas-liquid separator, expanded by the second flow rate control means, and then returned to the expansion power recovery means. 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 of the second bypass flow refrigerant route. An ejector can be used as the expansion power recovery means.

In such a refrigerating and air-conditioning apparatus, carbon dioxide can be used as a refrigerant.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment In a refrigerating and air-conditioning apparatus 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 annular with refrigerant pipes. And a fluorocarbon-based or hydrocarbon-based refrigerant is circulated. A heat exchanger 40 is installed between the condenser 12 and the flow rate control means 41, and the condenser 12 and the heat exchanger 40 and the evaporator 16 and the compressor 11 are connected by a bypass pipe 42. It is connected. The expander 13 is arranged 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. There is.
2 is a pressure-enthalpy diagram for explaining the refrigerating cycle of the refrigerating and air-conditioning apparatus, and points A to F shown in FIG. 2 are points A of the refrigerating and air-conditioning apparatus shown in FIG.
The pressure-enthalpy state is shown at each position corresponding to each point from F to F.

The operation and effects of such a refrigerating and air-conditioning apparatus will be described below with reference to the pressure-enthalpy diagram shown in FIG. In such a refrigerating and air-conditioning apparatus, 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 guided to the condenser 12 and condensed, and the enthalpy decreases with the pressure kept constant (point A → point B in the figure). 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 low-pressure refrigerant two-phase state (point B → point F in the figure). In the heat exchanger 40, the low-temperature low-pressure refrigerant exchanges heat with the refrigerant liquid circulating from the condenser 12 to the flow rate control unit 41 to be vaporized, and the pressure is recovered to a pressure equal to the suction pressure of the compressor 11 to recover the compressor. Returning to 11 (point F → point E in the figure), it will be used as part of the power of the compressor 11. Further, the rest of the refrigerant discharged from the condenser 12 is cooled by exchanging heat with the refrigerant having a low temperature and low pressure in the expander 13 in the heat exchanger 40 (point B → point C in the figure), and then flow rate control. The refrigerant is decompressed by the means 41 and becomes a low-temperature low-pressure gas-liquid two-layer state refrigerant (point C → D in the figure).
(Point) The gas is introduced into the evaporator 16, exchanges heat with air or the like, vaporizes, and returns to the compressor 11 (point D → point E in the figure). 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 the above refrigeration cycle is circulated again.

As described above, in such a refrigeration / air-conditioning system, the enthalpy of the refrigerant introduced into the flow rate control means can be reduced by subcooling the refrigerant circulating from the condenser to the flow rate control means by the heat exchanger. That is, the energy lost at the time of pressure reduction in the flow rate control means is recovered by the refrigerant circulating in the compressor without passing through the evaporator, and the efficiency UP due to the reduction of energy loss in the flow rate control means.
This enables highly efficient operation.

In the above embodiment, a fluorocarbon-based or hydrocarbon-based refrigerant is used. However, a refrigerating and air-conditioning system using carbon dioxide as a refrigerant causes a large energy loss during adiabatic expansion with respect to refrigerating capacity. The effect of the invention is particularly remarkable. Such effects 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 shows the inlet temperature of the flow rate control means 41 is 35 ° C. and the outlet temperature is 10
FIG. 3 is a pressure-enthalpy diagram in the adiabatic expansion process of a fluorocarbon-based refrigerant at ° C. 3 and 4,
50 and 60 are isotherms at 35 ° C., 51 and 61 are isentropic lines, 52 and 62 are isotherms at 10 ° C., 53 and 63 are energy losses, and 54 and 64 are refrigerating capacity. Figure 3
The energy loss 53 of carbon dioxide shown in FIG. 4 is larger than the energy loss 63 of the fluorocarbon-based refrigerant shown in FIG. 4 because carbon dioxide is in a critical state at 35 ° C. This is because it has a unique property different from that of the refrigerant. On the other hand, the present invention is intended to reduce the energy loss that occurs in the flow rate control means, and therefore, when carbon dioxide having such a large energy loss is used as the refrigerant, it is more effective than when using a normal fluorocarbon refrigerant. Is.

Embodiment 2 FIG. 5 is an example of a structural explanatory view showing the structure of a refrigerating and air-conditioning apparatus according to the present invention, which is a first compressor 11, a second condenser 45, and a second condenser 11.
Compressor 46, first condenser 12, first flow control means 41,
The evaporator 16 is sequentially connected in an annular shape by a refrigerant pipe, and a fluorocarbon-based or hydrocarbon-based refrigerant is circulated. Further, a heat exchanger 40 is installed between the condenser 12 and the first flow rate control means 41, and further the condenser 1
2 and the heat exchanger 40 and between the evaporator 16 and the compressor 11 are connected and connected by a bypass pipe 42. 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 part of the expander 13.
6 is a pressure-enthalpy diagram for explaining the refrigerating cycle of the refrigerating and air-conditioning apparatus, and points A'to H'shown in FIG. 6 are the refrigerating and air-conditioning apparatus shown in FIG. It represents the pressure-enthalpy state at each position corresponding to each point from A'to H'of.

The operation and effect of such a refrigerating and air-conditioning apparatus will be described below 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 by the second compressor 46 and brought into a high temperature and high pressure state is cooled by the first condenser 1
It is guided to 2 and condensed, and the enthalpy decreases with the pressure kept constant (point A '→ point B'in the figure). Part of the refrigerant liquid at the outlet of the first condenser 12 (point B ′ in the figure) is part of the expander 13
Adiabatically expands and changes to a low-temperature low-pressure refrigerant two-phase state (point B '→ H'in the figure). In the heat exchanger 40, the low-temperature low-pressure refrigerant exchanges heat with the refrigerant liquid circulating from the first condenser 12 to the flow rate control means 41 to be vaporized, and returns to the first compressor 11 (point H ′ in the figure → Point E '), which will be used as part of the power in the first compressor 11. First compressor 11
The refrigerant introduced in the first stage is first compressed (point E ′ → F ′ in the figure). The refrigerant compressed in the first stage is then guided to the second condenser 45 and condensed, and the enthalpy decreases with the pressure kept constant (point F ′ → G ′ in the figure).
point). Further, the refrigerant discharged from the second condenser 45 is compressed in the second stage by the second compressor 46 (point G ′ in the figure →
A'point). The rest of the refrigerant discharged 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 ′ → C ′ in the figure). The refrigerant is decompressed by the flow rate control means 41 and becomes a low-temperature low-pressure refrigerant in a gas-liquid two-layer state (point C ′ → D ′ in the figure), which is introduced into the evaporator 16 and heat-exchanges with air or the like to be vaporized and thus the first compressor. Return to 11 (point D '→ E'in the figure). From the evaporator 16 to the first compressor 1
The refrigerant returned to No. 1 from the above-mentioned bypass pipe 42 is the first
Like the refrigerant circulating in the compressor 11, the first compressor 11 and the second compressor 11
A high temperature and high pressure state is achieved by passing through the condenser 45 and the second compressor 46 (point E ′ → F ′ point → G ′ point →
Point A '), the refrigeration cycle described above is circulated again.

As described above, in the refrigerating and air-conditioning apparatus, the refrigerant compression step is performed in two stages, so that the energy lost during the pressure reduction in the flow rate control means passes through the evaporator as in the first embodiment. There is an advantage that efficiency is improved by reducing the energy loss in the flow rate control means by recovering with the refrigerant that circulates in the compressor without any need, and the power required for the compressor can be reduced and the efficiency is further improved. .

In the above-mentioned embodiment, the one using the fluorocarbon type or hydrocarbon type refrigerant has been described. However, when carbon dioxide is used as the refrigerant of the refrigerating and air-conditioning apparatus, the present invention is the same as in the first embodiment. The effect is particularly remarkable and suitable.

Embodiment 3 FIG. 7 is an example of a constitutional view showing the constitution of a 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 refrigerant pipes. They are sequentially connected in a ring shape, and have a configuration in which a 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, the first bypass pipe is provided between the condenser 12 and the heat exchanger 40 and between the evaporator 16 and the compressor 11. It is connected and connected at 42. The ejector 13 and the gas-liquid separator 14 are installed in the first bypass pipe 42, and further, the gas-liquid separator 14,
Second flow rate control means 43, heat exchanger 40 and ejector 13
Are connected by the second bypass pipe 44. Further, FIG. 8 is a pressure-enthalpy diagram for explaining the refrigeration cycle of such a refrigerating and air-conditioning apparatus, and points a to k shown in FIG. 8 are points a to k of the refrigerating and air-conditioning apparatus shown in FIG. 7. To k
It represents the pressure-enthalpy state at each position corresponding to each point of.

The operation of the refrigerating and air-conditioning apparatus and its effects will be described below 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 by the compressor 11 and brought into a high temperature and high pressure state is guided to the condenser 12 and condensed, and the enthalpy decreases with the pressure kept constant (point a → point b in the figure). 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 undergoes adiabatic expansion in the ejector 13 to become a low-temperature low-pressure refrigerant two-phase state. Change (point b in the figure →
f point. Here, the point f means the position immediately after the adiabatic expansion of the refrigerant in the ejector). The low-temperature low-pressure two-phase refrigerant is mixed with the refrigerant introduced from the gas-liquid separator 14 into the ejector 13 through the second flow rate control means 43 and the heat exchanger 40, and the enthalpy and pressure increase ( (Point f → point g → point h). The refrigerant with increased enthalpy and pressure is introduced into the gas-liquid separator 14 and separated into a gas phase and a liquid phase, of which the refrigerant vapor circulates to the compressor 11 through the first bypass pipe 42 (in the figure). h point → e point). In addition, the refrigerant that has become a liquid phase in the gas-liquid separator 14 (h in the figure
The point → point i) circulates through the second bypass pipe 44 to the second flow rate control means 43, and the pressure is reduced (point i → j in the figure).
point). This low-temperature low-pressure refrigerant vapor is transferred to the heat exchanger 40.
At, the heat exchange with the refrigerant flowing from the condenser 12 to the first flow rate control means 41 causes the enthalpy to increase (point j → point k in the figure).
The refrigerant whose enthalpy has increased is the second bypass pipe 44.
Is introduced into the ejector 13 through the condenser 1 and the condenser 1 as described above.
2, which is mixed with the high-pressure refrigerant introduced into the ejector 13 through the first bypass pipe 42 to reduce the enthalpy,
The pressure increases (point k → point g → point h in the figure). Further, the rest of the refrigerant discharged from the condenser 12 is cooled by exchanging heat with the refrigerant having a low temperature and low pressure in the ejector 13 in the heat exchanger 40 (point b → c in the figure), and then the flow rate control means. It is decompressed at 41 to become a low-temperature low-pressure gas-liquid two-phase refrigerant (point c in the figure →
(Point d) The gas is introduced into the evaporator 16, exchanges heat with air or the like, vaporizes, and returns to the compressor 11 (point d → point e in the figure). 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 the above refrigeration cycle is circulated again.

As described above, in such a refrigerating and air-conditioning apparatus, the refrigerant expanded by the ejector is separated by the gas-liquid separator and expanded again by the second flow rate control means to further reduce the temperature and pressure of the refrigerant, The refrigerant that circulates from the condenser to the flow rate control unit can be subcooled more efficiently. That is,
Energy lost in the flow rate control means of the mainstream refrigerant route is efficiently recovered by the lower temperature and low pressure refrigerant circulating in the second bypass flow refrigerant route, thereby reducing energy loss in the flow rate control means. As a result, the efficiency can be increased, and the refrigerating and air-conditioning apparatus can be operated efficiently as in the first and second embodiments.

In the above-mentioned embodiment, the case where the fluorocarbon-based or hydrocarbon-based refrigerant is used has been described. However, when carbon dioxide is used as the refrigerant of the refrigerating and air-conditioning apparatus, the same method as in the first and second embodiments is used. The effect of the invention is particularly remarkable and preferable.

[0021]

As described above, the refrigerating and air-conditioning apparatus according to the present invention is
Compressor, condenser, flow rate control means for reducing the pressure of the refrigerant and a mainstream refrigerant route connected to the evaporator to sequentially circulate the refrigerant, and part of the refrigerant is branched from the outlet side of the condenser,
Cooling the refrigerant on the inlet side of the flow rate control means on the mainstream refrigerant route by the bypass flow refrigerant route that expands the branched refrigerant by the expansion power recovery means and returns it to the compressor inlet side, and the expanded refrigerant on the bypass flow refrigerant route And a heat exchanger for reducing the energy loss in the flow control means by supercooling the refrigerant supplied from the condenser to the flow control means by the refrigerant whose temperature has been lowered by the expansion power recovery means. Therefore, it is possible to realize a refrigerating air-conditioning system that operates with high efficiency. Further, 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 to make the compressor The required power is reduced and the efficiency is further improved, which is preferable. Furthermore, when an expander is used as the expansion power recovery means, the expansion of the refrigerant can be performed easily and highly efficiently, which is more preferable.

Such a refrigerating and air-conditioning system includes a compressor, a condenser,
A mainstream refrigerant route in which the first flow rate control means for reducing the pressure of the refrigerant and the evaporator are connected so that the refrigerant circulates sequentially;
A part of the refrigerant is branched from the outlet side of the condenser, the branched refrigerant is expanded by the expansion power recovery means, and then the inlet of the compressor is passed through a gas-liquid separator that separates the expanded refrigerant into a gas phase and a liquid phase. The first bypass flow refrigerant route returning to the side and the second bypass branching the refrigerant from the liquid phase side of the gas-liquid separator, expanding the branched refrigerant by the second flow rate control means, and then returning to the expansion power recovery means When a flow refrigerant route and a heat exchanger for cooling the refrigerant on the inlet side of the flow rate control means in the mainstream refrigerant route with the expanded refrigerant of the second bypass flow refrigerant route are provided, the first flow rate control from the condenser The refrigerant supplied to the means,
By supercooling by using the refrigerant whose temperature and pressure are lowered by the second flow rate control means, the energy loss in the first flow rate control means is more efficiently reduced, and the energy recovered by cooling this refrigerant is used. By increasing the enthalpy of the refrigerant and introducing it into the expansion power recovery means and returning it to the compressor through the gas-liquid separator, the operating efficiency of the compressor can be improved, and a refrigerating and air-conditioning system that operates with high efficiency can be realized. . Moreover, when an ejector is used as the expansion power recovery means, the refrigerant can be expanded efficiently at low cost, which is preferable.

Such a refrigerating and air-conditioning apparatus is suitable because the loss due to the flow rate control means can be effectively reduced when the refrigerant is carbon dioxide.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view 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 refrigerating and air-conditioning apparatus according to the present invention.

[Fig. 3] Pressure when carbon dioxide is used as a refrigerant-
It is an enthalpy diagram.

FIG. 4 is a pressure-enthalpy diagram when a fluorocarbon-based refrigerant is used.

FIG. 5 is a configuration explanatory view showing a configuration of a refrigerating and air-conditioning apparatus according to the present invention.

FIG. 6 is a pressure-enthalpy diagram corresponding to the refrigerating and air-conditioning apparatus according to the present invention.

FIG. 7 is a configuration explanatory view showing a configuration of a refrigerating and air-conditioning apparatus 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 a configuration explanatory view showing a configuration of a conventional refrigeration system.

[Explanation of symbols] 9 refrigeration cycle, 11 compressor, 12 condenser, 13
Ejector, 14 gas-liquid separator, 15 refrigerant pump, 1
6 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, 4
4 2nd bypass piping, 45 2nd condenser, 46 2nd
Compressor, 50 35 ° C isotherm, 51 isentropic line, 52 10 ° C isotherm, 53 energy loss, 5
4 refrigerating capacity, 60 35 ° C isotherm, 61 isentropic curve, 62 10 ° C isotherm, 63 energy loss, 64 refrigerating capacity.

Continued front page    (72) Inventor Masayuki Tsunoda             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Fumitake Unezaki             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd.

Claims (6)

[Claims] 1. A mainstream refrigerant route connecting a compressor, a condenser, a flow control means for reducing the pressure of the refrigerant and an evaporator so that the refrigerant circulates sequentially, and a part of the refrigerant is branched from the outlet side of the condenser. The bypass flow refrigerant route that expands the branched refrigerant by the expansion power recovery means and returns it to the inlet side of the compressor, and the flow rate control means in the main flow refrigerant route by the expanded refrigerant of the bypass flow refrigerant route. A refrigerating and air-conditioning apparatus comprising: a heat exchanger that cools the refrigerant on the inlet side. 2. In the mainstream refrigerant route, a second condenser and a second condenser are provided from an outlet side of the compressor to an inlet side of the condenser.
The refrigerating and air-conditioning apparatus according to claim 1, wherein the compressors are sequentially connected. 3. The refrigerating and air-conditioning apparatus according to claim 1, wherein the expansion power recovery means is an expander. 4. A mainstream refrigerant route in which a compressor, a condenser, a first flow rate control means for reducing the pressure of the refrigerant, and an evaporator are connected so that the refrigerant circulates sequentially, and a part of the refrigerant from the outlet side of the condenser. And a first bypass flow refrigerant route for returning the branched refrigerant to the inlet side of the compressor through a gas-liquid separator for separating the expanded refrigerant into a gas phase and a liquid phase after the expanded refrigerant is expanded by the expansion power recovery means. A second bypass flow refrigerant route for branching the refrigerant from the liquid phase side of the gas-liquid separator, expanding the branched refrigerant by the second flow rate control means, and then returning it to the expansion power recovery means; (2) A refrigerating and air-conditioning apparatus comprising: 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 in the bypass flow refrigerant route. 5. The refrigerating and air conditioning apparatus according to claim 4, wherein the expansion power recovery means is an ejector. 6. The refrigerating and air-conditioning apparatus according to claim 1, wherein the refrigerant is carbon dioxide.