WO2019208428A1 - Ejector-type refrigeration cycle - Google Patents

Abstract

An ejector-type refrigeration cycle (10) comprising a compressor (11), a radiator (12), a high-stage-side pressure reduction unit (14a), a high-stage-side evaporator (15), a low-stage side pressure reduction unit (14c), a low-stage-side evaporator (18), a branching unit (13a), and an ejector (16). The branching unit (13a) divides a refrigerant flow downstream from the radiator (12), causing one divided flow of refrigerant to flow toward the high-stage-side pressure reduction unit (14a) and another divided flow of refrigerant to flow toward the low-stage-side pressure reduction unit (14c). The ejector (16) has a pressure-increasing unit (16a) that draws in, from a refrigerant intake opening (16c), the refrigerant flowing from the low-stage-side evaporator (18), increases the pressure of a mixed refrigerant comprising an injection refrigerant and the indrawn refrigerant, and causes the mixed refrigerant to flow toward the intake-opening side of the compressor (11). In addition, the ejector-type refrigeration cycle (10) is equipped with an enthalpy adjustment unit (14b, 17) that lowers the enthalpy of the refrigerant flowing to the low-stage-side evaporator (18).

Description

Ejector refrigeration cycle Cross-reference of related applications

This application is based on Japanese Patent Application No. 2018-87044 filed on April 27, 2018, the contents of which are incorporated herein by reference.

The present disclosure relates to an ejector-type refrigeration cycle including a plurality of evaporators that evaporate a refrigerant in different temperature zones.

Conventionally, an ejector-type refrigeration cycle, which is a vapor compression refrigeration cycle apparatus including an ejector, is known.

In this type of ejector-type refrigeration cycle, the refrigerant flowing out of the evaporator is sucked from the refrigerant suction port of the ejector due to the suction action of the high-speed jet refrigerant injected from the nozzle portion of the ejector. Then, the pressure of the mixed refrigerant of the injected refrigerant and the suction refrigerant is increased by the diffuser portion (pressure increasing portion) of the ejector, and the pressure-increased mixed refrigerant is sucked into the compressor.

Thus, in the ejector-type refrigeration cycle, the power consumption of the compressor is reduced and the coefficient of performance (COP) of the cycle is reduced compared to a normal refrigeration cycle apparatus in which the refrigerant evaporation pressure in the evaporator and the suction refrigerant pressure in the compressor are substantially equal. ) Can be improved.

Furthermore, Patent Document 1 discloses an ejector-type refrigeration cycle including a plurality of evaporators that evaporate refrigerant in different temperature zones.

More specifically, the ejector-type refrigeration cycle of Patent Document 1 includes a branch portion that branches the flow of the refrigerant flowing out of the condenser. And one refrigerant | coolant branched in the branch part is pressure-reduced in a high stage side pressure reduction part, and flows in into a high stage side evaporator. Further, the refrigerant that has flowed out of the high-stage evaporator is caused to flow into the nozzle portion of the ejector. Further, the other refrigerant branched at the branching section is depressurized by the low stage decompression section and flows into the low stage evaporator. Furthermore, it has a cycle configuration in which the refrigerant flowing out of the low-stage evaporator is sucked from the refrigerant suction port of the ejector.

Thus, in the ejector refrigeration cycle of Patent Document 1, the refrigerant evaporation temperature in the high stage evaporator and the refrigerant evaporation temperature in the low stage evaporator are set to different temperature zones.

JP 2012-149790 A

By the way, in the ejector-type refrigeration cycle of Patent Document 1, in order to adjust the cooling capacity exhibited by the high stage evaporator and the cooling capacity exhibited by the low stage evaporator, the flow rate ratio G_le / G_he is set to Adjust it. The flow ratio G_le / G_he is a ratio of the low-stage refrigerant flow rate G_le that is the flow rate of the refrigerant that flows into the low-stage evaporator to the high-stage refrigerant flow rate G_he that is the flow rate of the refrigerant that flows into the high-stage evaporator. .

Here, the flow rates of these refrigerants are all mass flow rates. The same applies to the flow rates of other refrigerants. The cooling capacity exhibited by the evaporator is an integration of the enthalpy difference Δh obtained by subtracting the enthalpy of the refrigerant on the inlet side of the evaporator from the enthalpy of the refrigerant on the outlet side of the evaporator and the flow rate G of the refrigerant flowing through the evaporator. It can be defined by the value Δh × G. Note that the flow rate of the refrigerant flowing through the evaporator is equal to the flow rate of the refrigerant flowing into the evaporator.

That is, in the ejector type refrigeration cycle of Patent Document 1, as the flow rate ratio G_le / G_he is increased, the cooling capacity exhibited by the high-stage evaporator can be reduced, and the low-stage evaporator can be reduced. Can increase the cooling capacity.

Conversely, in the ejector refrigeration cycle of Patent Document 1, as the flow rate ratio G_le / G_he is reduced, the cooling capacity exhibited by the high-stage evaporator can be increased, and the low-stage evaporator It is possible to reduce the cooling capacity exhibited in

Further, in a general ejector, the loss of velocity energy when the refrigerant is decompressed in the nozzle part is recovered by sucking the refrigerant by the suction action of the jet refrigerant injected from the nozzle part. Then, the mixed refrigerant is pressurized by converting the velocity energy of the mixed refrigerant of the injected refrigerant and the suction refrigerant into pressure energy in the diffuser section.

Therefore, in the ejector type refrigeration cycle of Patent Document 1, the flow rate ratio of the suction side flow rate Ge that is the flow rate of the refrigerant sucked into the refrigerant suction port of the ejector with respect to the nozzle side flow rate Gn that is the flow rate of the refrigerant flowing into the nozzle portion of the ejector. As Ge / Gn is reduced, it becomes easier to obtain the COP improvement effect of the ejector refrigeration cycle.

The reason is that as the flow rate ratio Ge / Gn is reduced, the flow rate of the injected refrigerant can be increased by increasing the flow rate of the refrigerant flowing into the nozzle portion. Thereby, the velocity energy of the mixed refrigerant can be increased, and the pressure increase amount ΔP in the diffuser portion can be increased. As a result, the COP improvement effect of the ejector refrigeration cycle is easily obtained as the flow rate ratio Ge / Gn is reduced.

Furthermore, in the cycle configuration of the ejector refrigeration cycle of Patent Document 1, the high stage side refrigerant flow rate G_he is equal to the nozzle part side flow rate Gn, and the low stage side refrigerant flow rate G_le is equal to the suction side flow rate Ge. For this reason, in the ejector type refrigeration cycle of Patent Document 1, if the flow rate ratio Ge / Gn (that is, the flow rate ratio G_le / G_he) is reduced in order to improve COP, the cooling capacity exhibited by the low-stage evaporator Will decrease.

This indication aims at providing the ejector type refrigerating cycle which can improve a coefficient of performance, without causing the reduction of the cooling capacity exhibited with a low stage side evaporator in view of the above-mentioned point.

An ejector refrigeration cycle according to the first aspect of the present disclosure includes a compressor, a radiator, a high-stage decompression unit, a high-stage evaporator, a low-stage decompression unit, a low-stage evaporator, A branch part and an ejector are provided.

Compressor compresses and discharges refrigerant. The radiator dissipates heat from the refrigerant discharged from the compressor. The high-stage decompression unit decompresses the refrigerant that has flowed out of the radiator. The high stage side evaporator evaporates the refrigerant decompressed by the high stage side decompression unit. The low-stage decompression unit decompresses the refrigerant that has flowed out of the radiator. The low stage side evaporator evaporates the refrigerant decompressed by the low stage side decompression unit. The branch section branches the flow of the refrigerant downstream of the radiator, causes one of the branched refrigerant to flow out to the refrigerant inlet side of the high-stage evaporator, and evaporates the other branched refrigerant to the low-stage side evaporation. To the refrigerant inlet side of the vessel. The ejector sucks the refrigerant that has flowed out of the low-stage evaporator from the refrigerant suction port by the suction action of the high-speed jet refrigerant that is jetted from the nozzle portion. The ejector has a boosting unit that boosts the pressure of the mixed refrigerant of the injected refrigerant and the suctioned refrigerant sucked from the refrigerant suction port and flows out to the suction port side of the compressor.

Furthermore, the ejector refrigeration cycle includes an enthalpy adjustment unit. The enthalpy adjustment unit reduces the enthalpy of the refrigerant flowing into the low stage side evaporator.

According to this, since the enthalpy adjustment unit is provided, the low stage side enthalpy difference Δh_le obtained by subtracting the enthalpy of the inlet side refrigerant from the enthalpy of the outlet side refrigerant of the low stage side evaporator can be increased.

Therefore, in order to improve the coefficient of performance, even if the flow ratio G_le / G_he of the low-stage refrigerant flow rate G_le with respect to the high-stage refrigerant flow rate G_he is reduced, the low-stage cooling capacity that is exhibited in the low-stage evaporator A decrease in Δh_le × G_le can be suppressed. The high-stage refrigerant flow rate G_he is a flow rate of the refrigerant that flows into the high-stage evaporator from the branch portion. The low stage side refrigerant flow rate G_le is a flow rate of the refrigerant that flows into the low stage side evaporator from the branch portion.

That is, according to the ejector refrigeration cycle of the first aspect of the present disclosure, it is possible to provide an ejector refrigeration cycle that can improve the coefficient of performance without causing a decrease in the low stage side cooling capacity Δh_le × G_le. it can.

It is a whole block diagram of the ejector-type refrigerating cycle of 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of operating the ejector-type refrigerating cycle of 1st Embodiment. It is a graph which shows the reduction effect of the flow rate ratio in the ejector type refrigerating cycle of a 1st embodiment. It is a graph which shows the relationship between ejector efficiency (eta) e and the coefficient of performance COP in the ejector-type refrigerating cycle of 1st Embodiment. It is a whole block diagram of the ejector type refrigerating cycle of 2nd Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of operating the ejector-type refrigerating cycle of 2nd Embodiment. It is a whole block diagram of the ejector-type refrigerating cycle of 3rd Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of operating the ejector type refrigeration cycle of 3rd Embodiment. It is a whole block diagram of the ejector-type refrigerating cycle of 4th Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of operating the ejector-type refrigerating cycle of 4th Embodiment.

Hereinafter, a plurality of modes for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, portions corresponding to those described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each embodiment, the other embodiments described above can be applied to other parts of the configuration. Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also combinations of the embodiments even if they are not explicitly stated unless there is a problem with the combination. Is also possible.

(First embodiment)
A first embodiment of the present disclosure will be described with reference to FIGS. The ejector refrigeration cycle 10 of this embodiment is applied to a vehicle refrigeration cycle apparatus mounted on a refrigerated vehicle. In a refrigerated vehicle, a vehicle refrigeration cycle apparatus air-conditions a passenger compartment and cools the inside of a refrigerator disposed on a loading platform of the vehicle.

Ejector refrigeration cycle 10 cools indoor blast air blown into the passenger compartment and cools blast air circulated into the refrigerator in the vehicle refrigeration cycle apparatus.

Therefore, in the present embodiment, both the vehicle interior space and the refrigerator internal space are cooling target spaces of the ejector refrigeration cycle 10. Furthermore, in this embodiment, the volume in a vehicle interior and a refrigerator is substantially equivalent, and the cooling capacity required in order to cool each cooling object space is also equivalent.

Here, the cooling capacity in the present embodiment includes the enthalpy difference Δh obtained by subtracting the enthalpy of the refrigerant on the inlet side of the evaporator from the enthalpy of the refrigerant on the outlet side of the evaporator provided in the ejector refrigeration cycle 10 and the flow rate of the refrigerant flowing through the evaporator. It is defined by an integrated value Δh × G with G.

The ejector refrigeration cycle 10 employs a natural refrigerant (specifically, R600a) as a refrigerant, and constitutes a vapor compression subcritical refrigeration cycle in which the refrigerant pressure on the high pressure side does not exceed the critical pressure of the refrigerant. Yes. Furthermore, refrigeration oil for lubricating the compressor 11 is mixed in the refrigerant, and a part of the refrigeration oil circulates in the cycle together with the refrigerant.

In the ejector refrigeration cycle 10 shown in the overall configuration diagram of FIG. 1, the compressor 11 sucks in refrigerant, compresses it, and discharges it. The compressor 11 is an electric compressor configured by housing a fixed capacity type compression mechanism and an electric motor for rotationally driving the compression mechanism in a housing. The operation of the compressor 11 is controlled by a control signal output from the control device 50 described later.

The refrigerant inlet side of the radiator 12 is connected to the discharge port of the compressor 11. The heat radiator 12 exchanges heat between the high-temperature and high-pressure discharged refrigerant discharged from the compressor 11 and the vehicle exterior air (outside air) blown by the cooling fan 12a to dissipate the high-pressure refrigerant and condense it. It is an exchanger. The cooling blower 12 a is an electric blower in which the rotation speed (that is, the amount of blown air) is controlled by a control voltage output from the control device 50.

The refrigerant outlet of the radiator 12 is connected to the refrigerant inlet side of the branch portion 13a. The branch part 13a branches the refrigerant flow on the downstream side of the radiator 12. The branch part 13a has a three-way joint structure having three refrigerant inlets and outlets communicating with each other, and one of the three refrigerant inlets and outlets is a refrigerant inlet and the remaining two are refrigerant outlets.

The inlet side of the high stage side expansion valve 14a is connected to one refrigerant outlet of the branch part 13a. The inlet side of the separator-side expansion valve 14b is connected to the other refrigerant outlet of the branch part 13a.

The high stage side expansion valve 14a is a high stage side decompression part that decompresses one refrigerant branched by the branch part 13a among the refrigerants radiated by the radiator 12. Furthermore, the high stage side expansion valve 14a is a high stage side flow rate adjusting unit that adjusts the flow rate of the refrigerant flowing out to the downstream side.

More specifically, the high stage side expansion valve 14a includes a valve body configured to be able to change the throttle opening degree and an electric actuator (specifically, a stepping motor) that changes the opening degree of the valve body. This is an electric variable aperture mechanism configured to have. The operation of the high stage side expansion valve 14 a is controlled by a control signal output from the control device 50.

The separator-side expansion valve 14b is a separator-side decompression unit that decompresses the other refrigerant branched by the branching unit 13a so as to be in a gas-liquid two-phase state. The separator-side expansion valve 14b is a separator-side flow rate adjusting unit that adjusts the flow rate of the refrigerant that flows out to the downstream side. The basic configuration of the separator side expansion valve 14b is the same as that of the high stage side expansion valve 14a.

The refrigerant inlet side of the high stage side evaporator 15 is connected to the outlet of the high stage side expansion valve 14a. The high stage side evaporator 15 heat-exchanges the low pressure refrigerant decompressed by the high stage side expansion valve 14a and the indoor blown air blown into the vehicle interior from the indoor blower 15a to evaporate the low pressure refrigerant. An endothermic heat exchanger that exhibits an endothermic effect. The indoor blower 15a is an electric blower in which the rotation speed (amount of blown air) is controlled by a control voltage output from the control device 50.

The refrigerant outlet of the higher stage evaporator 15 is connected to one refrigerant inlet side of the merging portion 13b. Junction part 13b merges the flow of the refrigerant that has flowed out of high-stage evaporator 15 and the flow of the gas-phase refrigerant that has flowed out of gas-liquid separator 17 described later. The basic configuration of the merging portion 13b is the same as that of the branching portion 13a. The merging section 13b uses two of the three refrigerant inflow / outflow ports as refrigerant inflow ports and the remaining one as a refrigerant outflow port.

The inlet side of the nozzle portion 16a of the ejector 16 is connected to the refrigerant outlet of the junction portion 13b. The ejector 16 has a nozzle portion 16a that injects the refrigerant that has flowed out of the high-stage evaporator 15 while further reducing the pressure. Therefore, the ejector 16 is a refrigerant decompression unit. Further, the ejector 16 is a refrigerant circulation unit that sucks and circulates the refrigerant from the outside by a suction action of the refrigerant injected from the refrigerant injection port of the nozzle portion 16a.

In addition, the ejector 16 converts the kinetic energy of the mixed refrigerant of the refrigerant injected from the nozzle portion 16a and the refrigerant sucked from the refrigerant suction port 16c into pressure energy, and increases the pressure of the mixed refrigerant. Part.

The ejector 16 has a nozzle portion 16a and a body portion 16b. The nozzle portion 16a is formed of a substantially cylindrical metal (in this embodiment, a stainless alloy) that gradually tapers in the refrigerant flow direction. The nozzle portion 16a decompresses the refrigerant in an isentropic manner in the refrigerant passage formed inside.

The refrigerant passage formed in the nozzle portion 16a includes a throat portion where the passage cross-sectional area is most reduced, and a divergent portion where the passage cross-sectional area gradually increases from the throat toward the refrigerant injection port for injecting the refrigerant. Is formed. That is, the nozzle portion 16a of the present embodiment is configured as a Laval nozzle.

Furthermore, in the present embodiment, the nozzle portion 16a is set such that the flow rate of the injected refrigerant injected from the refrigerant injection port is equal to or higher than the sonic speed during normal operation of the ejector refrigeration cycle 10. Of course, you may comprise the nozzle part 16a with a tapered nozzle.

The body portion 16b is made of a substantially cylindrical metal (in this embodiment, aluminum). The body portion 16b functions as a fixing member that supports and fixes the nozzle portion 16a therein, and forms a refrigerant passage through which the refrigerant flows. More specifically, the nozzle portion 16a is fixed by press-fitting so as to be housed inside the longitudinal end of the body portion 16b. The body part 16b may be formed of resin.

Of the outer peripheral surface of the body portion 16b, a portion corresponding to the outer peripheral side of the nozzle portion 16a is formed with a refrigerant suction port 16c provided so as to penetrate the inner and outer sides and communicate with the refrigerant injection port of the nozzle portion 16a. ing. The refrigerant suction port 16c is a through hole that sucks the refrigerant that has flowed out from the low-stage evaporator 18 (described later) into the ejector 16 by the suction action of the jet refrigerant injected from the nozzle portion 16a.

A suction passage 16e and a diffuser portion 16d are formed inside the body portion 16b. The suction passage 16e is a refrigerant passage that guides the suction refrigerant sucked from the refrigerant suction port 16c to the refrigerant injection port side of the nozzle portion 16a. The diffuser portion 16d is a refrigerant passage that functions as a pressure increasing portion that increases the pressure by mixing the suction refrigerant and the injection refrigerant.

More specifically, the suction passage 16e is formed by a space with an annular cross section between the outer peripheral side around the tapered tip of the nozzle portion 16a and the inner peripheral side of the body portion 16b. The passage cross-sectional area of the suction passage 16e is reduced as the refrigerant flows toward the downstream side. Thus, the flow rate of the suction refrigerant flowing through the suction passage 16e is increased, and energy loss (so-called mixing loss) when the suction refrigerant and the injection refrigerant are mixed in the diffuser portion 16d is reduced.

The diffuser portion 16d is a refrigerant passage that extends in a truncated cone shape so as to be continuous with the outlet of the suction passage 16e. In the diffuser portion 16d, the passage cross-sectional area increases as the refrigerant flows toward the downstream side. The diffuser portion 16d converts the kinetic energy of the mixed refrigerant into pressure energy by such a passage shape.

In the present embodiment, the axial cross-sectional shape of the inner peripheral wall surface of the body portion 16b forming the diffuser portion 16d is formed into a shape combining a plurality of curves. And since the degree of spread of the passage cross-sectional area of the diffuser portion 16d becomes larger as it goes in the refrigerant flow direction and then becomes smaller again, the pressure of the refrigerant can be increased isentropically. The inlet of the compressor 11 is connected to the outlet of the diffuser portion 16d.

The inlet side of the gas-liquid separator 17 is connected to the outlet of the separator-side expansion valve 14b. The gas-liquid separator 17 is a gas-liquid separator that separates the gas-liquid of the refrigerant decompressed by the separator-side expansion valve 14b. As such a gas-liquid separation unit, a centrifugal separation type that separates the gas-liquid refrigerant by the action of centrifugal force, or the gas-liquid of the refrigerant whose flow velocity is lowered by colliding with the collision plate is caused by the action of gravity. The thing of the collision plate system etc. which isolate | separate can be employ | adopted.

The gas-phase refrigerant outlet of the gas-liquid separator 17 is connected to the other refrigerant inlet side of the merging portion 13b. In other words, the gas-phase refrigerant outlet of the gas-liquid separator 17 is connected to the inlet side of the nozzle portion 16 a of the ejector 16. The liquid-phase refrigerant outlet of the gas-liquid separator 17 is connected to the inlet side of the low stage side expansion valve 14c.

The low-stage expansion valve 14c is a low-stage decompression unit that decompresses the liquid-phase refrigerant separated by the gas-liquid separator 17 among the refrigerant radiated by the radiator 12. Furthermore, the low-stage side expansion valve 14c is a low-stage side flow rate adjusting unit that adjusts the flow rate of the refrigerant that flows out to the downstream side. The basic configuration of the low stage side expansion valve 14c is the same as that of the high stage side expansion valve 14a and the separator side expansion valve 14b.

The refrigerant inlet side of the low stage side evaporator 18 is connected to the outlet of the low stage side expansion valve 14c. The low-stage evaporator 18 exchanges heat between the low-pressure refrigerant decompressed by the low-stage side expansion valve 14c and the internal blown air circulated through the refrigerator from the internal blower 18a. This is an endothermic heat exchanger that evaporates to exert an endothermic effect. The internal blower 18a is an electric blower in which the rotation speed (the amount of blown air) is controlled by a control voltage output from the control device 50.

As described above, the refrigerant suction port 16 c side of the ejector 16 is connected to the refrigerant outlet of the low-stage evaporator 18.

As is clear from the above description, the branching portion 13a branches the refrigerant flow on the downstream side of the radiator 12. Then, one of the refrigerants branched at the branch part 13a is caused to flow out to the refrigerant inlet side of the high stage side evaporator 15 via the high stage side expansion valve 14a. Further, the other refrigerant branched at the branching portion 13a is caused to flow out to the refrigerant inlet side of the low stage side evaporator 18 through at least the low stage side expansion valve 14c.

Further, the separator-side expansion valve 14b depressurizes the other refrigerant branched at the branching portion 13a so as to become a gas-liquid two-phase refrigerant. Therefore, the gas-liquid separator 17 can reliably separate the gas-liquid refrigerant. Then, the enthalpy of the refrigerant flowing out from the liquid-phase refrigerant outlet of the gas-liquid separator 17 can be surely lowered than the enthalpy of the refrigerant flowing into the gas-liquid separator 17.

In other words, the enthalpy of the refrigerant that flows out from the liquid-phase refrigerant outlet of the gas-liquid separator 17 and flows into the low-stage evaporator 18 through the low-stage expansion valve 14c is branched at the branching section 13a. The enthalpy can be lowered. Therefore, the separator-side expansion valve 14b and the gas-liquid separator 17 of this embodiment constitute an enthalpy adjusting unit that reduces the enthalpy of the refrigerant flowing into the low-stage evaporator 18.

In the ejector refrigeration cycle 10, the flow rate of the refrigerant discharged from the compressor 11 is defined as the discharge flow rate Ga. The flow rate of the refrigerant flowing into the high stage side evaporator 15 is defined as the high stage side refrigerant flow rate G_he. The flow rate of the refrigerant flowing into the low stage side evaporator 18 is defined as the low stage side refrigerant flow rate G_le. The flow rate of the refrigerant flowing into the nozzle portion 16a of the ejector 16 is defined as the nozzle side flow rate Gn. The flow rate of the refrigerant sucked into the refrigerant suction port 16c of the ejector 16 is defined as a suction side flow rate Ge. The flow rate of the refrigerant flowing out from the gas-phase refrigerant outlet of the gas-liquid separator 17 is defined as a gas-phase refrigerant flow rate G_gas. The flow rate of the refrigerant flowing out from the liquid phase refrigerant outlet of the gas-liquid separator 17 is defined as a liquid phase refrigerant flow rate G_lq. The flow rates of these refrigerants are all mass flow rates.

In the ejector refrigeration cycle 10, the relationships shown in the following formulas F1 to F4 are established for each flow rate.
Ga = G_he + G_gas + G_lq (F1)
Gn = G_he + G_gas (F2)
Ge = G_lq (F3)
Ge = G_le (F4)
That is, the discharge flow rate G is equal to the sum of the high-stage refrigerant flow rate G_he, the gas-phase refrigerant flow rate G_gas, and the liquid-phase refrigerant flow rate G_lq. The nozzle side flow rate Gn is equal to the total value of the high stage side refrigerant flow rate G_he and the gas phase refrigerant flow rate G_gas. The suction side flow rate Ge is equal to the liquid phase refrigerant flow rate G_lq. Further, the suction side flow rate Ge is equal to the low stage side refrigerant flow rate G_le.

Next, the electric control unit of this embodiment will be described. The control device 50 is composed of a known microcomputer including a CPU, ROM, RAM, and its peripheral circuits. The control device 50 performs various calculations and processes based on the control program stored in the ROM, and controls the operations of the various control target devices 11, 12a, 14a to 14c, 15a, 18a, etc. connected to the output side. To do.

A control sensor group 51 such as an inside air temperature sensor, an outside air temperature sensor, a solar radiation sensor, a high stage evaporator temperature sensor, and a low stage evaporator temperature sensor is connected to the input side of the control device 50. Then, the detection signal of the control sensor group 51 is input to the control device 50.

The inside air temperature sensor is an inside air temperature detecting unit that detects a vehicle interior temperature (inside air temperature) Tr. The outside air temperature sensor is an outside air temperature detecting unit that detects a vehicle compartment outside temperature (outside air temperature) Tam. A solar radiation sensor is a solar radiation amount detection part which detects the solar radiation amount As irradiated to a vehicle interior. The high stage evaporator temperature sensor is an evaporator temperature detector that detects the refrigerant evaporation temperature (high stage evaporator temperature) Te_he in the high stage evaporator 15. The low-stage evaporator temperature sensor is a low-stage evaporator temperature detector that detects a high-stage evaporator temperature (low-stage evaporator temperature) Te_le in the low-stage evaporator 18.

Furthermore, on the input side of the control device 50, an operation panel 52 disposed near the instrument panel in the front part of the passenger compartment is connected. Then, operation signals from various operation switches provided on the operation panel 52 are input to the control device 50. As various operation switches provided on the operation panel 52, an operation switch for requesting operation or stop of the vehicle refrigeration cycle apparatus, a vehicle interior temperature setting switch for setting the vehicle interior temperature, and an interior temperature setting for setting the interior temperature. A switch or the like is provided.

Here, the control device 50 of the present embodiment is a device in which a control unit that controls the operation of various devices to be controlled connected to the output side is integrally configured. And the structure (hardware and software) which controls the action | operation of each control object apparatus among the control apparatuses 50 comprises the control part of each control object apparatus.

For example, in the present embodiment, the configuration for controlling the operation of the compressor 11 constitutes a compressor control unit. For example, the configuration for controlling the operation of the high stage side expansion valve 14a and the low stage side expansion valve 14c is a flow ratio between the high stage side refrigerant flow rate G_he and the low stage side refrigerant flow rate G_le, or the nozzle side flow rate Gn and the suction side. A flow rate control unit that controls the flow rate ratio with the flow rate Ge is configured.

Next, the operation of the ejector refrigeration cycle 10 of this embodiment will be described using the Mollier diagram of FIG. First, when the operation switch of the operation panel 52 is turned on (ON), the control device 50 operates various devices to be controlled. Thereby, the compressor 11 sucks the refrigerant, compresses it, and discharges it.

The high-temperature and high-pressure discharged refrigerant (point a2 in FIG. 2) discharged from the compressor 11 flows into the radiator 12. The refrigerant flowing into the radiator 12 exchanges heat with the outside air blown from the cooling fan 12a, dissipates heat and condenses (point a2 → b2 in FIG. 2). The flow of the refrigerant flowing out of the radiator 12 is branched at the branching portion 13a.

One of the refrigerants branched at the branching portion 13a flows into the high stage expansion valve 14a and is decompressed in an enthalpy manner (b2 point → c2 point in FIG. 2). At this time, the throttle opening degree of the high stage side expansion valve 14a is adjusted so that the degree of superheat of the high stage side evaporator 15 outlet side refrigerant (point d2 in FIG. 2) falls within a predetermined range.

The low-pressure refrigerant decompressed by the high-stage expansion valve 14 a flows into the high-stage evaporator 15. The low-pressure refrigerant flowing into the high-stage evaporator 15 absorbs heat from the indoor air blown from the indoor fan 15a and evaporates (point c2 → d2 in FIG. 2). Thereby, the indoor blowing air is cooled. Here, the enthalpy difference between the point d2 and the point c2 in FIG. 2 is a high stage side enthalpy difference Δh_he obtained by subtracting the enthalpy of the inlet side refrigerant from the enthalpy of the outlet side refrigerant of the high stage side evaporator 15.

The superheated gas phase refrigerant (point d2 in FIG. 2) that has flowed out of the high-stage evaporator 15 flows into the junction 13b and is separated by the gas-liquid separator 17 (in FIG. 2). j2 point) (d2 point → e2 point, j2 point → e2 point in FIG. 2). The gas-phase refrigerant (point e2 in FIG. 2) that has flowed out from the merging portion 13b flows into the nozzle portion 16a of the ejector 16.

The refrigerant that has flowed into the nozzle portion 16a of the ejector 16 is isentropically decompressed and injected (point e2 → point f2 in FIG. 2). The refrigerant (n2 point in FIG. 2) flowing out from the low-stage evaporator 18 is sucked from the refrigerant suction port 16c of the ejector 16 by the suction action of the jet refrigerant.

When the refrigerant sucked from the refrigerant suction port 16c flows through the suction passage 16e formed inside the ejector 16, it is isentropically reduced to slightly reduce the pressure (point n2 → o2 in FIG. 2). ). The refrigerant injected from the nozzle portion 16a and the suction refrigerant sucked from the refrigerant suction port 16c flow into the diffuser portion 16d of the ejector 16 (f2 → g2 point, o2 point → g2 point in FIG. 2).

In the diffuser portion 16d, the velocity energy of the refrigerant is converted into pressure energy by expanding the refrigerant passage area. Thereby, the pressure of the mixed refrigerant of the injected refrigerant and the suction refrigerant increases (g2 point → h2 point in FIG. 2). The refrigerant flowing out of the diffuser portion 16d is sucked into the compressor 11 and compressed again (point h2 → point a2 in FIG. 2).

On the other hand, the other refrigerant branched at the branching portion 13a flows into the separator-side expansion valve 14b and is decompressed in an enthalpy manner (b2 point → i2 point in FIG. 2). At this time, the opening degree of the separator-side expansion valve 14b is such that the refrigerant pressure in the gas-liquid separator 17 is higher than the refrigerant pressure on the refrigerant outlet side of the high-stage evaporator 15, and the high-stage evaporator 15 is. It is adjusted to approach the refrigerant pressure on the refrigerant outlet side.

For this reason, the pressure reduction amount of the refrigerant in the separator side expansion valve 14b of the present embodiment is reduced by the pressure reduction amount of the refrigerant in the high stage side expansion valve 14a and the pressure loss generated when the refrigerant flows through the high stage side evaporator 15. Approach the total value with the amount.

The refrigerant decompressed by the separator-side expansion valve 14b becomes a gas-liquid two-phase refrigerant and flows into the gas-liquid separator 17. The refrigerant flowing into the gas-liquid separator 17 is separated into a gas-phase refrigerant and a liquid-phase refrigerant (i2 point → j2 point, i2 point → k2 point in FIG. 2). The gas-phase refrigerant (point j2 in FIG. 2) separated by the gas-liquid separator 17 flows into the junction 13b and has a superheat degree that has flowed out of the high-stage evaporator 15 as described above. (Point d2 in FIG. 2).

The liquid-phase refrigerant separated by the gas-liquid separator 17 (point k2 in FIG. 2) flows into the low-stage side expansion valve 14c and is decompressed in an enthalpy manner (point k2 → point m2 in FIG. 2). At this time, the throttle opening degree of the low stage side expansion valve 14c is adjusted so that the refrigerant evaporation temperature in the low stage side evaporator 18 approaches the target internal temperature set by the internal temperature setting switch.

The low-pressure refrigerant decompressed by the low-stage expansion valve 14 c flows into the low-stage evaporator 18. The low-pressure refrigerant that has flowed into the low-stage evaporator 18 absorbs heat from the blown air for the inside of the cabinet circulated from the blower 18a for the inside of the cabinet and evaporates (point m2 → n2 in FIG. 2). As a result, the internal blown air is cooled. Here, the enthalpy difference between the n2 point and the m2 point in FIG. 2 is a low stage side enthalpy difference Δh_le obtained by subtracting the enthalpy of the inlet side refrigerant from the enthalpy of the outlet side refrigerant of the low stage side evaporator 18.

As described above, the refrigerant that has flowed out of the low-stage evaporator 18 is sucked from the refrigerant suction port 16c of the ejector 16 (point n2 → point o2 → point g2 in FIG. 2).

Since the ejector refrigeration cycle 10 of the present embodiment operates as described above, it is possible to cool the indoor blast air blown into the vehicle interior and the internal blast air circulated into the refrigerator. At this time, the refrigerant evaporation pressure (that is, the refrigerant evaporation temperature) of the low-stage evaporator 18 is lower than the refrigerant evaporation pressure (that is, the refrigerant evaporation temperature) of the high-stage evaporator 15, so Can be cooled in different temperature zones.

Furthermore, in the ejector-type refrigeration cycle 10 of the present embodiment, the refrigerant (h2 point in FIG. 2) pressurized by the diffuser portion 16d of the ejector 16 is sucked into the compressor 11. Therefore, the power consumption of the compressor 11 can be reduced and the coefficient of performance (COP) of the cycle can be improved.

Incidentally, in order to increase the pressure increase amount ΔP in the diffuser portion 16d, the flow rate ratio Ge / Gn of the suction side flow rate Ge to the nozzle portion side flow rate Gn may be reduced. This is because the flow rate of the injected refrigerant can be increased by increasing the flow rate of the refrigerant flowing into the nozzle portion 16a as the flow rate ratio Ge / Gn is reduced. Therefore, in the ejector refrigeration cycle 10, it is easy to improve COP as the flow rate ratio Ge / Gn is reduced.

However, as is clear from the above formulas F1 and F2, reducing the flow rate ratio Ge / Gn is synonymous with reducing the flow rate ratio G_le / (G_he + G_gas).

Therefore, if the flow rate ratio Ge / Gn is reduced to improve COP, the low-stage refrigerant flow rate G_le of the refrigerant flowing into the low-stage evaporator 18 tends to decrease. That is, if the flow rate ratio Ge / Gn is reduced, the low-stage cooling capacity Δh_le × G_le exhibited by the low-stage evaporator may be reduced.

Furthermore, in the refrigeration cycle apparatus for a vehicle according to the present embodiment, as described above, the cooling capacity necessary for cooling the passenger compartment is equal to the cooling capacity required for cooling the refrigerator. Therefore, it is necessary to bring the low stage side cooling capacity Δh_le × G_le close to the high stage side cooling capacity Δh_he × G_he exhibited by the high stage evaporator.

On the other hand, according to the ejector refrigeration cycle 10 of the present embodiment, the enthalpy adjustment unit including the separator-side expansion valve 14b and the gas-liquid separator 17 is provided. Therefore, the low stage enthalpy difference Δh_le obtained by subtracting the enthalpy of the inlet side refrigerant from the enthalpy of the outlet side refrigerant of the low stage evaporator 18 can be increased.

More specifically, it corresponds to + Δh in FIG. 2 rather than the enthalpy difference in the low-stage evaporator of an ejector-type refrigeration cycle (hereinafter referred to as a comparative cycle) that does not include an enthalpy adjustment unit of the prior art. The enthalpy difference of minutes can be increased.

Therefore, in order to improve COP, even if the flow rate ratio Ge / Gn is reduced and the low-stage side refrigerant flow rate G_le is reduced, the low-stage side cooling capacity Δh_le × G_le is prevented from decreasing. be able to. In other words, the low-stage cooling capacity Δh_le × G_le can be brought close to the high-stage cooling capacity Δh_he × G_he without bringing the flow ratio Ge / Gn close to 1.

According to the study of the inventors of the present disclosure, as shown in FIG. 3, in the ejector refrigeration cycle 10 of the present embodiment, if the flow rate ratio Ge / Gn is 0.791, the flow rate ratio in the comparative cycle is As in the case where Ge / Gn is set to 1, it has been confirmed that the low stage side cooling capacity Δh_le × G_le and the high stage side cooling capacity Δh_he × G_he can be brought close to each other.

Further, as shown in Formula F2, the nozzle portion side flow rate Gn is a total value of the high stage side refrigerant flow rate G_he and the gas phase refrigerant flow rate G_gas. Therefore, in the ejector-type refrigeration cycle 10 of the present embodiment, the nozzle unit side flow rate Gn can be increased by the gas phase refrigerant flow rate G_gas rather than the nozzle unit side flow rate of the comparison cycle.

As a result, the flow rate ratio G_le / (G_he + G_gas) can be reduced, and the pressure increase amount ΔP in the diffuser portion 16d can be further increased to improve the COP.

Here, according to studies by the inventors of the present disclosure, as shown in FIG. 4, in the ejector refrigeration cycle 10 of the present embodiment, the flow rate ratio Ge / Gn is 1, and the ejector efficiency ηe is 0.5. It has been confirmed that the COP can be improved by about 3% compared to the comparative cycle when the ejector 16 is adopted. The ejector efficiency ηe is the energy conversion efficiency of the ejector, and is a value determined by the operating conditions of the ejector refrigeration cycle 10, the dimensions of the ejector 16, and the like.

That is, according to the ejector refrigeration cycle 10 of the present embodiment, COP can be improved without causing a decrease in the cooling capacity exhibited by the low-stage evaporator 18.

Further, in the ejector type refrigeration cycle 10 of the present embodiment, the separator-side expansion valve 14b and the gas-liquid separator 17 constitute an enthalpy adjustment unit. Further, the inlet side of the high stage side expansion valve 14 a is connected to one refrigerant outlet of the branch part 13 a, and the inlet side of the nozzle part 16 a is connected to the refrigerant outlet of the high stage side evaporator 15.

The inlet side of the separator side expansion valve 14b is connected to the other refrigerant outlet of the branch part 13a. The inlet side of the nozzle portion 16 a is connected to the gas phase refrigerant outlet of the gas-liquid separator 17. The inlet side of the low stage side expansion valve 14 c is connected to the liquid phase refrigerant outlet of the gas-liquid separator 17. Therefore, the above-described COP improvement effect can be obtained with a simple cycle configuration.

Further, the throttle opening degree of the separator side expansion valve 14b of the present embodiment is adjusted so that the refrigerant pressure in the gas-liquid separator 17 approaches the refrigerant pressure on the refrigerant outlet side of the high stage evaporator 15.

According to this, the flow of the gas-phase refrigerant having the superheat degree that has flowed out of the high-stage evaporator 15 at the merging portion 13b without causing the reverse flow of the refrigerant from the merging portion 13b to the gas-liquid separator 17 side. And the flow of the gas-phase refrigerant flowing out from the gas-phase refrigerant outlet of the gas-liquid separator 17 can be appropriately mixed and supplied to the nozzle portion 16a.

(Second Embodiment)
This embodiment demonstrates the example which changed the cycle structure of the ejector-type refrigerating cycle 10 with respect to 1st Embodiment, as shown in the whole block diagram of FIG. In FIG. 5, the control device 50, the control sensor group 51, the operation panel 52, and the like are omitted for clarity of illustration. In FIG. 5, the same or equivalent parts as those in the first embodiment are denoted by the same reference numerals. The same applies to the following drawings.

The inlet side of the high stage side expansion valve 14a is connected to the refrigerant outlet of the radiator 12 of the ejector refrigeration cycle 10 of the present embodiment. The refrigerant inlet side of the branch part 13a is connected to the outlet of the high stage side expansion valve 14a. The refrigerant inlet side of the high-stage evaporator 15 is connected to one refrigerant outlet of the branch part 13a. Other configurations are the same as those of the first embodiment.

Next, the operation of the ejector refrigeration cycle 10 of this embodiment will be described using the Mollier diagram of FIG. In FIG. 6, the state of the refrigerant at the same location in the cycle configuration with respect to the Mollier diagram of FIG. 2 described in the first embodiment is indicated by the same reference numeral (alphabet) as in FIG. Only has been changed to match the figure number. The same applies to other Mollier diagrams described below.

The high-temperature and high-pressure discharged refrigerant (point a6 in FIG. 6) discharged from the compressor 11 flows into the radiator 12 and condenses (point a6 → b6 in FIG. 6), as in the first embodiment. The refrigerant that has flowed out of the radiator 12 flows into the high stage expansion valve 14a and is decompressed in an enthalpy manner (b6 point → c6 point in FIG. 2). At this time, the throttle opening degree of the high stage side expansion valve 14a is adjusted such that the degree of superheat of the high stage side evaporator 15 outlet side refrigerant (point d6 in FIG. 6) is within a predetermined range.

The flow of the low-pressure refrigerant that has flowed out of the high stage side expansion valve 14a is branched at the branching portion 13a. One of the refrigerants branched at the branching portion 13a flows into the high-stage evaporator 15 and evaporates by absorbing heat from the indoor blast air as in the first embodiment (point c6 → d6 in FIG. 6). point). Thereby, indoor ventilation air is cooled.

The other refrigerant branched at the branching portion 13a flows into the separator-side expansion valve 14b and is decompressed isoenthalpiically (point c6 → point i6 in FIG. 6). At this time, the throttle opening of the separator-side expansion valve 14b is within a range in which the refrigerant pressure in the gas-liquid separator 17 is higher than the refrigerant pressure on the refrigerant outlet side of the high-stage evaporator 15 as in the first embodiment. Thus, the refrigerant pressure is adjusted so as to approach the refrigerant pressure on the refrigerant outlet side of the high-stage evaporator 15. Subsequent operations are the same as those in the first embodiment.

Therefore, even in the ejector refrigeration cycle 10 of the present embodiment, the same effect as that of the first embodiment can be obtained. That is, the COP of the ejector refrigeration cycle 10 can be improved without causing a decrease in the cooling capacity exhibited by the low-stage evaporator 18.

(Third embodiment)
In the present embodiment, an ejector refrigeration cycle 10a in which the cycle configuration is changed as shown in the overall configuration diagram of FIG. 7 with respect to the first embodiment will be described.

Specifically, the inlet side of the nozzle portion 16a of the ejector 16 is connected to the gas-phase refrigerant outlet of the gas-liquid separator 17 of the ejector refrigeration cycle 10a. The other refrigerant inlet side of the merging portion 13b is connected to the outlet of the diffuser portion 16d of the ejector 16. The suction port side of the compressor 11 is connected to the refrigerant outlet of the junction 13b. Other configurations are the same as those of the first embodiment.

Accordingly, in the ejector refrigeration cycle 10a of the present embodiment, the formulas F1, F3, and F4 described in the first embodiment are satisfied for each flow rate, but the formula F2 is not satisfied. In place of the formula F2, the relationship shown in the following formula F5 is established.
Gn = G_gas (F5)
That is, the nozzle side flow rate Gn is equal to the gas-phase refrigerant flow rate G_gas.

Next, the operation of the ejector refrigeration cycle 10a of this embodiment will be described using the Mollier diagram of FIG.

The high-temperature and high-pressure discharged refrigerant (point a8 in FIG. 8) discharged from the compressor 11 flows into the radiator 12 and condenses (point a8 → b8 in FIG. 8), as in the first embodiment. The flow of the refrigerant flowing out of the radiator 12 is branched at the branching portion 13a, and one of the branched refrigerants is connected to the high-stage evaporator via the high-stage side expansion valve 14a as in the first embodiment. 15 and evaporates (b8 point → c8 point → d8 point in FIG. 8). Thereby, indoor ventilation air is cooled.

The refrigerant that has flowed out of the high-stage evaporator 15 flows into the merging portion 13b and merges the refrigerant that has flowed out of the diffuser portion 16d of the ejector 16 (d8 point → e8 point, h8 point → e8 point in FIG. 8). The refrigerant flowing out from the junction 13b is sucked into the compressor 11 and compressed again (point e8 → point a8 in FIG. 8).

Further, the other branched refrigerant is decompressed by the separator-side expansion valve 14b and gas-liquid separated by the gas-liquid separator 17 as in the first embodiment (b8 point → i8 point in FIG. 8). → j8 points, b8 points → i8 points → k8 points). At this time, the throttle opening of the separator-side expansion valve 14b is adjusted so that the COP approaches the maximum value (peak value).

Here, since the refrigerant that flows into the gas-liquid separator 17 is the refrigerant that has been reduced in an enthalpy manner by the separator-side expansion valve 14b, the degree of dryness increases as the pressure decreases. For this reason, the gas-phase refrigerant flow rate G_gas increases and the liquid-phase refrigerant flow rate G_lq decreases as the pressure of the refrigerant flowing into the gas-liquid separator 17 decreases. Furthermore, the inlet side of the nozzle portion 16 a of the ejector 16 is connected to the gas-phase refrigerant outlet of the gas-liquid separator 17 instead of the ejector refrigeration cycle 10 a.

Therefore, as the pressure of the refrigerant flowing into the gas-liquid separator 17 decreases, the gas-phase refrigerant flow rate G_gas (that is, the nozzle-side flow rate Gn) is increased to increase the pressure increase amount ΔP in the diffuser portion 16d of the ejector 16. Cheap. On the other hand, as the pressure of the refrigerant flowing into the gas-liquid separator 17 decreases, the liquid-phase refrigerant flow rate G_lq (that is, the low-stage refrigerant flow rate G_le) decreases, so the low-stage cooling capacity Δh_le × G_le is It tends to decrease.

Therefore, in the ejector refrigeration cycle 10a, the COP changes to have a maximum value (peak value) with respect to the change in the pressure of the refrigerant flowing into the gas-liquid separator 17. Therefore, in this embodiment, the throttle opening degree of the separator-side expansion valve 14b is adjusted so that the COP approaches the maximum value (peak value).

The gas-phase refrigerant (j8 point in FIG. 8) separated by the gas-liquid separator 17 flows into the nozzle portion 16a of the ejector 16. The refrigerant that has flowed into the nozzle portion 16a of the ejector 16 is isentropically depressurized and injected as in the first embodiment (point j8 → point f8 in FIG. 8). As a result, the refrigerant (n8 point in FIG. 8) flowing out from the low-stage evaporator 18 is sucked from the refrigerant suction port 16c of the ejector 16 (n8 point → o8 point in FIG. 8).

Further, similarly to the first embodiment, the injected refrigerant and the suction refrigerant are boosted by the diffuser portion 16d and flow into the other refrigerant inlet of the merging portion 13b (f8 point → g8 point → h8 point in FIG. 8). In FIG. 8, point o8 → g8 → h8).

The liquid refrigerant (point k8 in FIG. 8) separated by the gas-liquid separator 17 flows into the low-stage evaporator 18 via the low-stage expansion valve 14c, as in the first embodiment. It evaporates (m8 point → n8 point in FIG. 8). As a result, the internal blown air is cooled. Subsequent operations are the same as those in the first embodiment.

Therefore, also in the ejector refrigeration cycle 10a of the present embodiment, the COP of the ejector refrigeration cycle 10a is reduced without reducing the cooling capacity exhibited by the low-stage evaporator 18 as in the first embodiment. Can be improved.

Here, in FIG. 8, the pressure of the refrigerant depressurized by the separator side expansion valve 14b (point i8 in FIG. 8) is the pressure of the refrigerant depressurized by the high stage side expansion valve 14a (point c8 in FIG. 8). However, the relationship between the two is not limited to this.

That is, if the throttle opening of the separator-side expansion valve 14b is adjusted so that the COP of the ejector-type refrigeration cycle 10a approaches the maximum value, the pressure of the refrigerant decompressed by the separator-side expansion valve 14b (see FIG. 8 (i8 point) may be equal to or higher than the pressure of the refrigerant decompressed by the high stage side expansion valve 14a (point c8 in FIG. 8).

(Fourth embodiment)
In the present embodiment, an example in which the cycle configuration of the ejector refrigeration cycle 10a is changed as shown in the overall configuration diagram of FIG. 9 with respect to the third embodiment will be described.

The inlet side of the high stage side expansion valve 14a is connected to the refrigerant outlet of the radiator 12 of the ejector refrigeration cycle 10 of the present embodiment. The refrigerant inlet side of the branch part 13a is connected to the outlet of the high stage side expansion valve 14a. The refrigerant inlet side of the high-stage evaporator 15 is connected to one refrigerant outlet of the branch part 13a. Other configurations are the same as those of the third embodiment.

Next, the operation of the ejector refrigeration cycle 10 of the present embodiment will be described using the Mollier diagram of FIG.

The high-temperature and high-pressure discharged refrigerant (point a10 in FIG. 10) discharged from the compressor 11 is condensed by the radiator 12 (point a10 → b10 in FIG. 10), as in the third embodiment. The refrigerant flowing out of the radiator 12 flows into the high stage side expansion valve 14a and is decompressed in an enthalpy manner (b10 point → c10 point in FIG. 10). At this time, the throttle opening degree of the high stage side expansion valve 14a is adjusted so that the degree of superheat of the high stage side evaporator 1 outlet side refrigerant (point d10 in FIG. 10) falls within a predetermined range.

The flow of the low-pressure refrigerant that has flowed out of the high stage side expansion valve 14a is branched at the branching portion 13a. One refrigerant branched by the branching portion 13a flows into the high-stage evaporator 15, and, as in the third embodiment, absorbs heat from the indoor blast air and evaporates (point c10 → d10 in FIG. 10). point). Thereby, indoor ventilation air is cooled.

The other refrigerant branched at the branching portion 13a flows into the separator-side expansion valve 14b and is decompressed in an enthalpy manner (point c10 → point i10 in FIG. 10). At this time, the throttle opening degree of the separator-side expansion valve 14b is adjusted so that the COP approaches the maximum value (peak value) as in the third embodiment. Subsequent operations are the same as those in the first embodiment.

Accordingly, also in the ejector refrigeration cycle 10a of the present embodiment, the COP of the ejector refrigeration cycle 10a is reduced without reducing the cooling capacity exhibited by the low-stage evaporator 18 as in the third embodiment. Can be improved.

The present disclosure is not limited to the above-described embodiment, and various modifications can be made as follows without departing from the spirit of the present disclosure.

In the above-described embodiment, the example in which the enthalpy adjustment unit is configured by the separator-side expansion valve 14b and the gas-liquid separator 17 has been described, but the enthalpy adjustment unit is not limited thereto. For example, the enthalpy adjustment unit may be an internal heat exchanger that reduces the enthalpy of the refrigerant flowing into the low-stage evaporator 18 by exchanging heat between the refrigerant flowing into the low-stage evaporator 18 and a refrigerant having a temperature lower than that. May be adopted.

In each of the above-described embodiments, the example in which the ejector refrigeration cycle 10 according to the present disclosure is applied to a refrigeration cycle apparatus for a refrigerated vehicle has been described, but the application of the ejector refrigeration cycle 10 according to the present disclosure is not limited thereto.

For example, when applied to a vehicle, the ejector refrigeration cycle 10 according to the present disclosure may be applied to a so-called dual air conditioner system. In the dual air conditioner system, the front-seat blown air that is blown to the front seat side of the vehicle by the high-stage evaporator 15 is cooled, and the rear-seat blower that is blown to the rear side of the vehicle by the low-stage evaporator 18. Cool the air.

Furthermore, the present invention is not limited to vehicles, and may be applied to stationary refrigeration / freezers, showcases, air conditioners, and the like. At this time, among the plurality of cooling target spaces, the low-temperature side cooling target space whose temperature is desired to be lowered is cooled by the low-stage evaporator 18 and cooled in a higher temperature zone than the low-temperature side cooling target space. The target space may be cooled by the high-stage evaporator 15.

The components constituting the ejector refrigeration cycle 10 are not limited to those disclosed in the above embodiment.

For example, as the compressor 11, an engine-driven compressor driven by a rotational driving force transmitted from an engine (internal combustion engine) via a pulley, a belt, or the like may be employed. This type of engine-driven compressor includes a variable displacement compressor that can adjust the refrigerant discharge capacity by changing the discharge capacity, and a fixed type that adjusts the refrigerant discharge capacity by changing the operating rate of the compressor by intermittently connecting the electromagnetic clutch. A capacity type compressor or the like can be employed.

Also, as the radiator 12, a so-called subcool condenser may be adopted. The subcool type condenser has a condensing part, a modulator part, and a supercooling part. The condensing unit is a heat exchanging unit that condenses the discharged refrigerant by exchanging heat between the discharged refrigerant discharged from the compressor 11 and the outside air. A modulator part is a gas-liquid separation part which isolate | separates the gas-liquid of the refrigerant | coolant which flowed out from the condensation part. The supercooling unit is a heat exchange unit that supercools the liquid phase refrigerant by exchanging heat between the liquid phase refrigerant flowing out of the modulator unit and the outside air.

Further, a temperature type expansion valve may be adopted as the high stage side expansion valve 14a. The temperature type expansion valve has a temperature sensing part and a mechanical mechanism part. The temperature sensing unit has a deformable member (specifically, a diaphragm) that deforms according to the temperature and pressure of the refrigerant on the outlet side of the high-stage evaporator 15. The mechanical mechanism unit changes the throttle opening in conjunction with the deformation of the deformation member of the temperature sensing unit.

A temperature formula that adjusts the throttle opening so that the superheat degree of the refrigerant on the outlet side of the low-stage evaporator approaches either a predetermined reference superheat degree in either the separator-side expansion valve 14b or the low-stage side expansion valve 14c. An expansion valve may be employed. Furthermore, a fixed throttle (specifically, an orifice or a capillary tube) with a fixed throttle opening may be employed for the other.

Furthermore, a variable throttle mechanism may be adopted for any one of the high stage side expansion valve 14a, the separator side expansion valve 14b, and the low stage side expansion valve 14c. Further, a fixed throttle may be employed as the remaining expansion valve.

In the above-described embodiment, the example in which the fixed ejector having the fixed nozzle portion in which the passage cross-sectional area of the throat portion (minimum passage area portion) of the nozzle portion 16a does not change is employed as the ejector 16 has been described. As a modification, a variable ejector having a variable nozzle part capable of adjusting the passage sectional area of the throat may be used as the ejector 16.

In the above-described embodiment, the ejector- type refrigeration cycle 10 or 10a including the high-stage evaporator 15 and the low-stage evaporator 18 has been described. However, an evaporator may be further included.

For example, in the ejector refrigeration cycle 10 of the first embodiment, an auxiliary branch portion that further branches the other refrigerant branched by the branch portion 13a, and a bypass passage that connects the auxiliary branch portion and the suction port of the compressor 11 Is provided. And you may arrange | position an auxiliary pressure-reduction part and an auxiliary evaporator in a bypass channel.

For example, in the ejector refrigeration cycle 10 according to the first embodiment, the first auxiliary branch portion that branches the flow of the refrigerant depressurized by the high-stage expansion valve 14a, and the first auxiliary branch portion and the suction port of the compressor 11 A first bypass passage is provided. An auxiliary high-stage evaporator and an auxiliary ejector are arranged in the first bypass passage.

Furthermore, a second auxiliary branch portion for branching the refrigerant flow depressurized by the low-stage side expansion valve 14c and a second bypass passage for connecting the second auxiliary branch portion and the refrigerant suction port of the auxiliary ejector are provided. An auxiliary low-stage evaporator may be disposed in the second bypass passage.

In the above-described embodiment, the example in which R600a is adopted as the refrigerant has been described, but the refrigerant is not limited to this. For example, R134a, R1234yf, R410A, R404A, R32, R1234yfxf, R407C, etc. can be employed. Or you may employ | adopt the mixed refrigerant | coolant etc. which mixed multiple types among these refrigerant | coolants.

Although the present disclosure has been described based on the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

Claims (6)

1. A compressor (11) for compressing and discharging the refrigerant;
   A radiator (12) for dissipating heat from the refrigerant discharged from the compressor;
   A high-stage decompression part (14a) for decompressing the refrigerant radiated by the radiator;
   A high stage evaporator (15) for evaporating the refrigerant decompressed in the high stage decompression section;
   A lower-stage decompression section (14c) for decompressing the refrigerant radiated by the radiator;
   A low-stage evaporator (18) for evaporating the refrigerant decompressed in the low-stage decompression section;
   The flow of the refrigerant on the downstream side of the radiator is branched, and one of the branched refrigerant flows out to the refrigerant inlet side of the high-stage evaporator, and the other branched refrigerant is supplied to the low-stage evaporator A branch part (13a) for flowing out to the refrigerant inlet side of
   Due to the suction action of the jet refrigerant injected from the nozzle section (16a) for depressurizing the refrigerant, the refrigerant flowing out from the low-stage evaporator is sucked from the refrigerant suction port (16c), and from the jet refrigerant and the refrigerant suction port. An ejector (16) having a pressure-increasing part (16d) for increasing the pressure of the mixed refrigerant with the sucked refrigerant and flowing out to the suction port side of the compressor,
   Furthermore, an ejector-type refrigeration cycle provided with an enthalpy adjustment unit (14b, 17) for reducing the enthalpy of the refrigerant flowing into the low-stage evaporator.
2. The enthalpy adjustment unit has a gas-liquid separation unit (17) that separates the gas-liquid refrigerant and a separator-side decompression unit (14b) that decompresses the refrigerant flowing into the gas-liquid separation unit,
   The refrigerant outlet of the radiator is connected to the inlet side of the branch portion,
   One outlet of the branch part is connected to an inlet side of the high-stage decompression part,
   The refrigerant outlet of the high-stage evaporator is connected to the inlet side of the nozzle part,
   The other outlet of the branch is connected to the inlet of the separator-side decompression unit,
   The gas-phase refrigerant outlet of the gas-liquid separation part is connected to the inlet side of the nozzle part,
   The ejector-type refrigeration cycle according to claim 1, wherein a liquid-phase refrigerant outlet of the gas-liquid separation unit is connected to an inlet side of the low-stage decompression unit.
3. The enthalpy adjustment unit has a gas-liquid separation unit (17) that separates the gas-liquid refrigerant and a separator-side decompression unit (14b) that decompresses the refrigerant flowing into the gas-liquid separation unit,
   The refrigerant outlet of the radiator is connected to the inlet side of the high-stage decompression unit,
   The outlet of the high-stage decompression part is connected to the inlet side of the branch part,
   One outlet of the branch portion is connected to a refrigerant inlet side of the high-stage evaporator,
   The refrigerant outlet of the high-stage evaporator is connected to the inlet side of the nozzle part,
   The other outlet of the branching portion is connected to the inlet side of the separator-side decompression portion (14b),
   The gas-phase refrigerant outlet of the gas-liquid separation part is connected to the inlet side of the nozzle part,
   The ejector-type refrigeration cycle according to claim 1, wherein a liquid-phase refrigerant outlet of the gas-liquid separation unit is connected to an inlet side of the low-stage decompression unit.
4. The said separator side decompression part adjusts throttle opening so that the pressure of the refrigerant | coolant in the said gas-liquid separation part may approach the pressure of the refrigerant | coolant of the exit side of the said high stage side evaporator (15). Or the ejector refrigeration cycle according to 3;
5. The enthalpy adjustment unit has a gas-liquid separation unit (17) that separates the gas-liquid refrigerant and a separator-side decompression unit (14b) that decompresses the refrigerant flowing into the gas-liquid separation unit,
   The refrigerant outlet of the radiator is connected to the inlet side of the branch portion,
   One outlet of the branch part is connected to an inlet side of the high-stage decompression part,
   The refrigerant outlet of the high-stage evaporator is connected to the inlet side of the compressor,
   The other outlet of the branch is connected to the inlet of the separator-side decompression unit,
   The gas-phase refrigerant outlet of the gas-liquid separation part is connected to the inlet side of the nozzle part,
   The ejector-type refrigeration cycle according to claim 1, wherein a liquid-phase refrigerant outlet of the gas-liquid separation unit is connected to an inlet side of the low-stage decompression unit.
6. The enthalpy adjustment unit has a gas-liquid separation unit (17) that separates the gas-liquid refrigerant and a separator-side decompression unit (14b) that decompresses the refrigerant flowing into the gas-liquid separation unit,
   The refrigerant outlet of the radiator is connected to the inlet side of the high-stage decompression unit,
   The outlet of the high-stage decompression part is connected to the inlet side of the branch part,
   One outlet of the branch portion is connected to a refrigerant inlet side of the high-stage evaporator,
   The refrigerant outlet of the high-stage evaporator is connected to the inlet side of the compressor,
   The other outlet of the branch is connected to the inlet of the separator-side decompression unit,
   The gas-phase refrigerant outlet of the gas-liquid separation part is connected to the inlet side of the nozzle part,
   The ejector-type refrigeration cycle according to claim 1, wherein a liquid-phase refrigerant outlet of the gas-liquid separation unit is connected to an inlet side of the low-stage decompression unit.

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