JP4849133B2 - Ejector refrigeration cycle - Google Patents

Description

  The present invention relates to an ejector-type refrigeration cycle having an ejector.

  2. Description of the Related Art Conventionally, an ejector refrigeration cycle having an ejector that functions as a refrigerant decompression unit and a refrigerant circulation unit is known. For example, Patent Documents 1 and 2 disclose an ejector-type refrigeration cycle in which a compressor discharge refrigerant dissipates heat by exchanging heat with outdoor air using a radiator and decompresses the dissipated high-pressure refrigerant at a nozzle portion of the ejector. ing.

  For example, in the ejector-type refrigeration cycle of Patent Document 1, a gas-liquid separator that separates the gas-liquid of the low-pressure refrigerant is disposed downstream of the diffuser portion of the ejector, and the gas-phase refrigerant outlet of the gas-liquid separator is connected to the compressor inlet side. And the liquid-phase refrigerant outlet is connected to the inlet of the suction-side evaporator, and the outlet of the suction-side evaporator is connected to the refrigerant suction port of the ejector.

  In an ejector applied to this type of ejector-type refrigeration cycle, high-pressure refrigerant is decompressed and expanded at the nozzle portion of the ejector, and the refrigerant on the downstream side of the evaporator is sucked from the refrigerant suction port by the pressure drop of the injected refrigerant. Thus, the loss of kinetic energy at the time of decompression expansion in the nozzle portion is recovered.

  Then, the recovered kinetic energy (hereinafter referred to as “recovered energy”) is converted into pressure energy by the diffuser portion of the ejector, and the pressure of the compressor suction refrigerant is increased. Thereby, the drive power of a compressor is reduced and the coefficient of performance (COP) of an ejector type refrigeration cycle is improved.

  Patent Document 2 is configured to be able to switch between a cooling operation mode refrigerant flow path for cooling indoor blown air that is a heat exchange target fluid and a heating operation mode refrigerant flow path for heating indoor blowing air. An ejector refrigeration cycle is disclosed.

Japanese Patent No. 3322263 JP 2002-327967 A

  However, in this type of ejector-type refrigeration cycle, the suction capacity of the ejector decreases as the flow rate of refrigerant (hereinafter referred to as drive flow) passing through the nozzle portion decreases, so the amount of recovered energy also decreases. End up. For this reason, the above-mentioned COP improvement effect will reduce with the flow volume fall of a drive flow.

  For example, in the ejector refrigeration cycle of Patent Document 1, when the pressure of the high-pressure refrigerant decreases as the outside air temperature decreases, the pressure difference between the high-pressure refrigerant and the low-pressure refrigerant decreases, and the flow rate of the ejector drive flow decreases. End up.

  When such a decrease in the flow rate of the drive flow occurs, not only the suction capacity of the ejector is reduced and the amount of recovered energy is reduced, but also the liquid-phase refrigerant is hardly supplied from the gas-liquid separator to the evaporator, and the cycle is The refrigeration capacity that can be exerted also decreases. As a result, the COP is significantly reduced as the driving flow rate decreases.

  Furthermore, if the suction capability of the ejector is reduced and refrigerant is no longer supplied to the evaporator, the low-pressure refrigerant cannot exhibit the endothermic effect in the evaporator, causing a problem that the cycle breaks down.

  This will be described in detail with reference to FIG. FIG. 5 is a Mollier diagram showing the refrigerant state of the ejector refrigeration cycle of Patent Document 1 (see FIG. 2 of Patent Document 1). Note that the solid line in FIG. 5 indicates the state of the refrigerant during normal operation, and the broken line indicates the state of the refrigerant when the above-described cycle failure occurs.

As is clear from FIG. 5, when the pressure difference between the high-pressure refrigerant and the low-pressure refrigerant is reduced due to a decrease in the outside air temperature (white arrow X _{5 in} FIG. ₅ ), the suction ability of the ejector is lowered. As a result, when the refrigerant is no longer supplied to the evaporator, the low-pressure refrigerant cannot exhibit an endothermic effect in the evaporator (open arrow Y _{5 in} FIG. ₅ ).

  For this reason, as shown by the broken line in FIG. 5, the amount of heat that can be radiated from the refrigerant by the radiator becomes equivalent to the compression work of the compressor. As a result, the amount of heat cannot be substantially transferred from the low pressure side to the high pressure side via the refrigerant, and the cycle fails.

  Moreover, in the ejector-type refrigeration cycle configured to be able to switch between the cooling operation mode and the heating operation mode as in Patent Document 2, at least when the ejector is switched to the refrigerant flow path that uses the refrigerant as the refrigerant decompression means, the same problem occurs. Arise.

  The present invention has been made in view of the above points, and an object of the present invention is to stably operate an ejector refrigeration cycle even when the flow rate fluctuation of the drive flow of the ejector occurs.

In order to achieve the above object, in the first aspect of the present invention, the first and second compression mechanisms (11a, 21a) for compressing and discharging the refrigerant and heat exchange between the refrigerant and the outside air are performed. An outdoor heat exchanger (41) to be used, a use side heat exchanger (51) for exchanging heat between the refrigerant and the heat exchange target fluid, and a high-speed jet refrigerant injected from the nozzle section (13a) for decompressing and expanding the refrigerant An ejector (13) for sucking the refrigerant from the refrigerant suction port (13b) by the flow and increasing the pressure of the mixed refrigerant of the injected refrigerant and the suction refrigerant sucked from the refrigerant suction port (13b) at the diffuser portion (13d); The high pressure side decompression means (12) for decompressing and expanding the refrigerant, and the gas-liquid separated from the refrigerant flowing out from the diffuser section (13d) or the refrigerant flowing out from the high pressure side decompression means (12) are separated into First compressor (11a) A gas-liquid separator (14) that flows out to the inlet side, a low-pressure side decompression means (15) that decompresses and expands the liquid-phase refrigerant separated by the gas-liquid separator (14), and a heat exchange target fluid And a refrigerant channel switching means (31, 32, 33, 34) for switching the refrigerant channel in the cooling operation mode for cooling the refrigerant channel in the heating operation mode for heating the heat exchange target fluid,
The refrigerant flow path switching means (31 to 34) is configured such that the first compression mechanism (41) of the outdoor heat exchanger (41) and the use side heat exchanger (51) is in one of the cooling operation mode and the heating operation mode. 11a) The refrigerant that has flowed out of the heat exchanger that dissipates the discharged refrigerant is caused to flow into the nozzle portion (13a), and among the outdoor heat exchanger (41) and the use side heat exchanger (51), the low pressure side pressure reducing means (15 ) The refrigerant flowing out from the heat exchanger that evaporates the refrigerant flowing out is switched to a refrigerant flow path that is sucked into the second compression mechanism (21a) and discharged to the refrigerant suction port (13b) side,
Outflow from the heat exchanger that radiates the refrigerant discharged from the first compression mechanism (11a) of the outdoor heat exchanger (41) and the use side heat exchanger (51) during the other operation mode of the cooling operation mode and the heating operation mode. From the heat exchanger that causes the low-pressure side decompression means (15) to evaporate the refrigerant out of the outdoor heat exchanger (41) and the use-side heat exchanger (51). The ejector-type refrigeration cycle is characterized in that the refrigerant flowing out is sucked into the second compression mechanism (21a) and switched to a refrigerant flow path for discharging to the suction port side of the first compression mechanism (11a).

  According to this, during one operation mode, the refrigerant flowing out of the heat exchanger functioning as a radiator out of the outdoor heat exchanger (41) and the use side heat exchanger (51) is discharged from the nozzle portion of the ejector (13) ( 13a), the refrigerant flowing out from the heat exchanger functioning as an evaporator of the outdoor heat exchanger (41) and the use side heat exchanger (51) is discharged from the refrigerant suction port (13b) of the ejector (13). An ejector-type refrigeration cycle for suction is configured.

  In this one operation mode, the second compression mechanism (21a) is moved from the heat exchanger functioning as an evaporator among the outdoor heat exchanger (41) and the use side heat exchanger (51) to the ejector (13). Since the refrigerant is discharged toward the refrigerant suction port (13b), the ejector (13) can be used even under operating conditions in which the suction capacity of the ejector (13) is reduced as the drive flow rate of the ejector (13) is reduced. The suction ability can be assisted.

  Therefore, in one operation mode in which the ejector-type refrigeration cycle is configured, the cycle is stably operated even under an operation condition in which the flow rate fluctuation of the drive flow occurs and the suction capacity of the ejector (13) decreases. be able to.

  Moreover, since the pressure of the refrigerant can be increased by the pressure increasing action of the two first and second compression mechanisms (11a, 21a) and the diffuser portion (13d) of the ejector (13), the pressure of the refrigerant is increased by one compressor. Thus, the COP can be improved by reducing the driving power of the first and second compression mechanisms (11a, 21a).

  That is, not only can the compressor drive power of the first compression mechanism (11a) be reduced by increasing the suction pressure of the first compression mechanism (11a) by the pressure increasing action of the diffuser portion (13d), Since the pressure difference between the suction pressure and the discharge pressure of the first and second compression mechanisms (11a, 21a) can be reduced, the compression efficiency of the first and second compression mechanisms (11a, 21a) can be improved.

  On the other hand, in the other operation mode, the refrigerant flowing out from the heat exchanger functioning as a radiator is decompressed by the high pressure side decompression means (12) and flows into the gas-liquid separator (14). ) And the second compression mechanism (21a) discharged refrigerant can be mixed and sucked into the first compression mechanism (11a).

  In this other operation mode, the refrigerant can be boosted in multiple stages, so that the suction in each of the first and second compression mechanisms (11a, 12a) is higher than when the refrigerant is boosted by a single compression means. By reducing the pressure difference between the refrigerant pressure and the discharge refrigerant pressure, the compression efficiency of each compression mechanism can be improved.

  Furthermore, since the first compression mechanism (11a) can suck the refrigerant obtained by joining the gas-phase refrigerant separated by the gas-liquid separator (14) and the refrigerant discharged from the second compression mechanism (21a), As compared with the case where only the refrigerant discharged by the two-compression mechanism (21a) is sucked, the amount of compression work when the refrigerant is isentropically compressed by the first compression mechanism (11a) can be reduced to improve the COP.

  Therefore, in the other operation mode, although the cycle using the ejector (13) as the refrigerant pressure reducing means is not configured, the cycle can be stably operated while exhibiting high COP.

  Thus, the ability to operate the ejector refrigeration cycle stably while exhibiting high COP is a refrigeration cycle apparatus having a large pressure difference between the high-pressure refrigerant and the low-pressure refrigerant, for example, the internal temperature is extremely low during the cooling operation mode. It is extremely effective when applied to a cold storage cabinet or the like used in an environment where the outside air as the heat absorption source is at a very low temperature in the heating operation mode.

  Further, as in the invention according to claim 2, in the ejector refrigeration cycle according to claim 1, the refrigerant flow switching means (31 to 34) discharges the first compression mechanism (11a) during the cooling operation mode. The refrigerant flows into the outdoor heat exchanger (41) to dissipate heat, and the low pressure side decompression means (15) switches the refrigerant flowing out to the utilization side heat exchanger (51) to the refrigerant flow path to evaporate, and the heating operation mode Sometimes, the refrigerant discharged from the first compression mechanism (11a) flows into the use side heat exchanger (51) to dissipate heat, and the low pressure side decompression means (15) flows into the outdoor heat exchanger (41) to evaporate. It is only necessary to switch to the refrigerant flow path.

  Thus, specifically, the heat exchange target fluid can be cooled by the use side heat exchanger (51) in the cooling operation mode, and heat exchange is performed by the use side heat exchanger (51) in the heating operation mode. The target fluid can be heated.

  In the invention according to claim 3, in the ejector refrigeration cycle according to claim 1 or 2, the first discharge capacity changing means (11b) for changing the refrigerant discharge capacity of the first compression mechanism (11a), and the second A second discharge capacity changing means (21b) for changing the refrigerant discharge capacity of the compression mechanism (21a), and the first discharge capacity changing means (11b) and the second discharge capacity changing means (21b) are independent of each other. The refrigerant discharge capacity of the first compression mechanism (11a) and the second compression mechanism (21a) is configured to be changeable.

  According to this, the refrigerant | coolant discharge capability of a 1st compression mechanism (11a) and the refrigerant | coolant discharge capability of a 2nd compression mechanism (21a) are adjusted independently, and either of a 1st, 2nd compression mechanism (11a, 21a) is adjusted. Can be operated while exhibiting high compression efficiency. Therefore, COP as the whole ejector type refrigerating cycle can be further improved.

  According to a fourth aspect of the present invention, in the ejector refrigeration cycle according to any one of the first to third aspects, the first compression mechanism (11a) and the second compression mechanism (21a) are in the same housing. It is accommodated and it is comprised integrally. Accordingly, the first compression mechanism (11a) and the second compression mechanism (21a) can be reduced in size, and the entire ejector refrigeration cycle can be reduced in size.

  As in the fifth aspect of the invention, in the ejector refrigeration cycle according to any one of the first to fourth aspects, the first compression mechanism (11a) is configured to increase the pressure of the refrigerant until it reaches a critical pressure or higher. It may be.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

1 is an overall configuration diagram of an ejector refrigeration cycle according to an embodiment. (A) is the Mollier diagram which shows the state of the refrigerant | coolant of the cooling operation mode of one Embodiment, (b) is the Mollier diagram which shows the state of the refrigerant | coolant of the heating operation mode of one Embodiment. (A) is a block diagram of the refrigerant | coolant flow path switching means in other embodiment, (b) is a block diagram of another refrigerant | coolant flow path switching means in other embodiment. It is a block diagram of another refrigerant flow path switching means in another embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant of the ejector-type refrigerating cycle of a prior art.

  1 and 2, an embodiment in which the ejector refrigeration cycle 100 of the present invention is applied to a cold storage container that keeps the internal temperature at a low temperature or a high temperature will be described. FIG. 1 is an overall configuration diagram of an ejector refrigeration cycle 100 of the present embodiment.

  The ejector refrigeration cycle 100 is configured to be switchable between a cooling operation mode for cooling the internal air that is a heat exchange target fluid and a heating operation mode for heating the internal air. In addition, the solid line arrow in FIG. 1 shows the flow of the refrigerant in the cooling operation mode, and the broken line arrow shows the flow of the refrigerant in the heating operation mode.

  In the ejector refrigeration cycle 100, the first compressor 11 sucks in refrigerant, compresses and discharges the refrigerant, and electrically compresses the first compression mechanism 11a having a fixed discharge capacity by the first electric motor 11b. Machine. Specifically, various compression mechanisms such as a scroll-type compression mechanism and a vane-type compression mechanism can be employed as the first compression mechanism 11a.

  The first electric motor 11b is controlled in its operation (number of rotations) by a control signal output from a control device described later, and may adopt either an AC motor or a DC motor. And the refrigerant | coolant discharge capability of the 1st compression mechanism 11a is changed by this rotation speed control. Therefore, the 1st electric motor 11b of this embodiment comprises the 1st discharge capability change means which changes the refrigerant discharge capability of the 1st compression mechanism 11a.

  An electric four-way valve 31 is connected to the discharge port side of the first compressor 11 (first compression mechanism 11a). The electric four-way valve 31 switches the refrigerant flow path in the cooling operation mode and the refrigerant flow path in the heating operation mode, and the refrigerant flow switching whose operation is controlled by a control signal output from the control device. Means.

  More specifically, the electric four-way valve 31 is provided between the discharge port side of the first compressor 11 and the outdoor heat exchanger 41 inlet side, the low pressure side fixed throttle 15 outlet side described later, and the usage side heat exchanger described later. The refrigerant flow path (the circuit indicated by the solid line arrow in FIG. 1) that connects the 51 inlet side at the same time, the first compressor 11 discharge side and the use side heat exchanger 51 inlet side, and the low pressure side fixed throttle The refrigerant flow path (circuit indicated by the broken line arrow in FIG. 1) that simultaneously connects the 15 outlet side and the outdoor heat exchanger 41 inlet side is switched.

  An outdoor heat exchanger 41 is connected via an electric four-way valve 31 to the discharge side of the first compressor 11 in the cooling operation mode, as in the refrigerant flow path indicated by the solid line arrow in FIG. The outdoor heat exchanger 41 is a heat exchanger that exchanges heat between the refrigerant passing through the inside and the outdoor air blown by the blower fan 41a. The blower fan 41a 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.

  Therefore, when the refrigerant discharged from the first compressor 11 having a temperature higher than the outside air temperature flows in the outdoor heat exchanger 41, the outdoor heat exchanger 41 functions as a radiator that radiates the refrigerant. Further, when the refrigerant flowing out of the low-pressure side fixed throttle 15 having a temperature lower than the outside air temperature flows in the outdoor heat exchanger 41, it functions as an evaporator for evaporating the refrigerant.

  In the ejector refrigeration cycle 100 of the present embodiment, a normal chlorofluorocarbon refrigerant is employed as the refrigerant, and a subcritical refrigeration cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant is configured. For this reason, the heat exchanger that functions as a radiator in the present embodiment acts as a condenser that condenses the refrigerant.

  The refrigerant is mixed with refrigerating machine oil that is soluble in the liquid phase refrigerant for lubricating the first and second compression mechanisms 11a and 21a, and the refrigerating machine oil circulates in the cycle together with the refrigerant. .

  Furthermore, the refrigerant inlet side of the first electric three-way valve 32 is connected to the outlet side of the outdoor heat exchanger 41 in the cooling operation mode. The first electric three-way valve 32 switches the refrigerant channel in the cooling operation mode and the refrigerant channel in the heating operation mode, and constitutes the refrigerant channel switching means in the present embodiment together with the electric four-way valve 31. ing. The operation of the first electric three-way valve 32 is controlled by a control signal output from the control device.

  Specifically, the first electric three-way valve 32 is a refrigerant flow path (circuit shown by a solid arrow in FIG. 1) that connects between the outlet side of the outdoor heat exchanger 41 and the inlet side of the nozzle portion 13a of the ejector 13. And the refrigerant | coolant flow path (circuit shown by the broken-line arrow of FIG. 1) which connects between the outdoor heat exchanger 41 exit side and the 2nd compressor 21 (2nd compression mechanism 21a) inlet side mentioned later is switched.

  A first three-way joint 17a is disposed between the first electric three-way valve 32 and the second compressor 21 suction side. The first three-way joint 17a is a refrigerant pipe joint member having three refrigerant inflow / outlets communicating with each other. Further, one refrigerant outlet of a second electric three-way valve 33 described later is connected to another refrigerant inlet / outlet of the first three-way joint 17a.

  The ejector 13 is a refrigerant decompression unit that decompresses and expands the refrigerant, and is also a refrigerant circulation unit that circulates the refrigerant by suction of a refrigerant flow ejected at high speed.

  More specifically, the ejector 13 squeezes the passage area of the high-pressure refrigerant flowing out of the outdoor heat exchanger 41 in the cooling operation mode to reduce the pressure of the high-pressure refrigerant in an isentropic manner. The refrigerant suction port 13b is disposed so as to communicate with the refrigerant injection port and sucks the refrigerant discharged from the second compressor 21.

  Furthermore, a mixing portion 13c that mixes the high-speed refrigerant flow ejected from the nozzle portion 13a and the suction refrigerant from the refrigerant suction port 13b is provided in the refrigerant flow downstream portion of the nozzle portion 13a and the refrigerant suction port 13b. A diffuser portion 13d forming a pressure increasing portion is provided on the refrigerant flow downstream side of the mixing portion 13c.

  The diffuser portion 13d is formed in a shape that gradually increases the refrigerant passage area, and functions to increase the refrigerant pressure by decelerating the refrigerant flow, that is, to convert the velocity energy of the refrigerant into pressure energy. Further, an accumulator 14 is connected to the outlet side of the diffuser portion 13d via a second three-way joint 17b.

  The accumulator 14 is a gas-liquid separator that separates the gas-liquid refrigerant flowing out of the diffuser portion 13d and accumulates excess liquid-phase refrigerant in the cycle. The suction port of the first compressor 11 is connected to the gas-phase refrigerant outlet of the accumulator 14 via a third three-way joint 17 c, and the liquid-phase refrigerant outlet is electrically connected via the low-pressure side fixed throttle 15. A four-way valve 31 is connected.

  The second and third three-way joints 17b and 17c are refrigerant pipe joint members having the same configuration as the first three-way joint 17a. Furthermore, a refrigerant outlet side of the high-pressure side fixed throttle 12 described later is connected to another refrigerant inlet / outlet of the second three-way joint 17b, and a third electric type described later is connected to another refrigerant inlet / outlet of the third three-way joint 17c. One refrigerant outlet of the three-way valve 34 is connected.

  The low-pressure-side fixed throttle 15 is a low-pressure-side decompression unit that further decompresses and expands the refrigerant flowing out of the accumulator 14. Specifically, an orifice or a capillary tube can be adopted as the low pressure side fixed throttle 15.

  The use side heat exchanger 51 is a heat exchanger that exchanges heat between the refrigerant passing through the inside and the internal air that is the heat exchange target fluid circulated and blown by the blower fan 51a. The blower fan 51a is an electric blower in which the rotation speed (amount of blown air) is controlled by a control voltage output from the control device.

  Therefore, the use side heat exchanger 51 functions as an evaporator for evaporating the refrigerant when the refrigerant flowing out of the accumulator 14 having a temperature lower than that in the storage air flows in the use side heat exchanger 51, and uses side heat exchange. When the refrigerant discharged from the first compressor 11 having a temperature higher than that of the internal air flows in the chamber 51, it functions as a radiator that radiates the refrigerant.

  A refrigerant inlet of the second electric three-way valve 33 is connected to the refrigerant outlet side of the use side heat exchanger 51. The basic configuration of the second electric three-way valve 33 is the same as that of the first electric three-way valve 32. Further, the second electric three-way valve 33 also constitutes the refrigerant flow switching means of the present embodiment together with the electric four-way valve 31 and the like.

  Specifically, the second electric three-way valve 33 includes a refrigerant flow path (circuit indicated by a solid line arrow in FIG. 1) that connects between the outlet side of the use side heat exchanger 51 and the first three-way joint 17a, and The refrigerant flow path (circuit indicated by the broken line arrow in FIG. 1) connecting the outlet side of the use side heat exchanger 51 and the inlet side of the high pressure side fixed throttle 12 is switched.

  As described above, one refrigerant inlet / outlet of the first three-way joint 17a is connected to one refrigerant outlet of the second electric three-way valve 33, and the high pressure side fixed throttle 12 is connected to the other refrigerant outlet. The refrigerant inlet side is connected. The high-pressure-side fixed throttle 12 is a high-pressure-side decompression unit that decompresses and expands the high-pressure refrigerant that has flowed out of the use-side heat exchanger 51 in the heating operation mode until the intermediate pressure is reached. Specifically, an orifice or a capillary tube can be adopted as the high-pressure side fixed throttle 12.

  The second compressor 21 sucks and compresses the refrigerant and discharges it to the refrigerant inlet side of the third electric three-way valve 34, and its basic configuration is the same as that of the first compressor 11. Accordingly, the second compressor 21 is an electric compressor that drives the fixed capacity type second compression mechanism 21a by the second electric motor 21b. Furthermore, the second electric motor 21b of the present embodiment constitutes a second discharge capacity changing means for changing the refrigerant discharge capacity of the second compression mechanism 21a.

  The basic configuration of the third electric three-way valve 34 is the same as that of the first and second electric three-way valves 32 and 33. Further, the third electric three-way valve 34 also constitutes the refrigerant flow switching means of the present embodiment together with the electric four-way valve 31 and the like.

  Specifically, the third electric three-way valve 34 is a refrigerant flow path (circuit indicated by a solid line arrow in FIG. 1) that connects between the second compressor 21 discharge port side and the refrigerant suction port side of the ejector 13. And the refrigerant | coolant flow path (circuit shown by the broken-line arrow of FIG. 1) which connects between the 2nd compressor 21 discharge port side and the 1st compressor 11 suction port side is switched.

  In the first to third electric three-way valves 32 to 34 described above, the other refrigerant flow path is closed when switched to one refrigerant flow path. Therefore, the refrigerant does not flow through the other refrigerant flow path, and the refrigerant does not leak from the inside of the cycle to the outside.

  A control device (not shown) includes a known microcomputer including a CPU, a ROM, a RAM, and the like and peripheral circuits thereof. This control device performs various calculations and processes based on the control program stored in the ROM, and operates the above-described various electric actuators 11b, 21b, 31, 32, 33, 34, 41a, 51a, etc. To control.

  Therefore, this control device functions as a first discharge capacity control means for controlling the operation of the first electric motor 11b as the first discharge capacity change means, and operates as the second electric motor 21b as the second discharge capacity change means. Function as second discharge capacity control means for controlling the flow rate, and refrigerant flow path switching control means for controlling the operation of the electric four-way valve 31 and the first to third electric three-way valves 32 to 34 which are flow path switching means Have both. Of course, the first discharge capacity control means, the second discharge capacity control means, and the medium / refrigerant flow path switching control means may be configured by different control devices.

  In addition, the control device includes an outside air sensor that detects the outside air temperature, a detection value of a sensor group (not shown) such as an inside temperature sensor that detects the inside temperature, an operation switch that operates the cold storage chamber, and cools the inside air. Various operation signals of an operation panel (not shown) provided with a mode changeover switch between a cooling operation mode for heating and a heating operation mode for heating the internal air are input.

  Next, the operation of the present embodiment in the above configuration will be described based on the Mollier diagram of FIG. 2A is a Mollier diagram showing the state of the refrigerant in the cooling operation mode, and FIG. 2B is a Mollier diagram showing the state of the refrigerant in the heating operation mode.

  First, the cooling operation mode will be described. The cooling operation mode is executed when the operation switch of the operation panel is turned on and the cooling operation mode is selected by the mode changeover switch. In the cooling operation mode, the control device operates the first and second electric motors 11b and 21b and the blower fans 41a and 51a, and the electric four-way valve 31 and the first to third electric three-way valves 32 to 34 are indicated by solid lines. Switch to the circuit indicated by the arrow.

Therefore, the refrigerant (point a _{2a in} FIG. 2A) compressed by the first compressor 11 (first compression mechanism 11a) flows into the outdoor heat exchanger 41 via the electric four-way valve 31. The heat is exchanged with the blown air (outside air) blown from the blower fan 41a to dissipate and condense (a _2a point → b _2a point). That is, in the cooling operation mode of this embodiment, the outdoor heat exchanger 41 functions as a radiator.

The refrigerant radiated by the outdoor heat exchanger 41 flows into the nozzle portion 13a of the ejector 13 via the first electric three-way valve 32, and isentropically decompressed and expanded (b _2a point → c _2a point). And the pressure energy of a refrigerant | coolant is converted into speed energy at the time of this decompression | expansion expansion, and a refrigerant | coolant is injected at high speed from the refrigerant | coolant injection port of the nozzle part 13a.

Due to the refrigerant suction action of the injected refrigerant, the refrigerant (point j _2a ) discharged from the second compressor 21 (second compression mechanism 21a) from the refrigerant suction port 13b is sucked through the third electric three-way valve 34. Is done.

Further, the refrigerant injected from the nozzle portion 13a and the suction refrigerant sucked from the refrigerant suction port 13b are mixed in the mixing portion 13c of the ejector 13 and flow into the diffuser portion 13d (points c _2a → d _2a and j _2a point → d _2a point). In the diffuser portion 13d, the refrigerant pressure energy rises due to expansion of the passage area, so that the refrigerant pressure rises (d _2a point → e _2a point).

The refrigerant flowing out of the diffuser portion 13d flows into the accumulator 14 through the second three-way joint 17b and is separated into a gas phase refrigerant and a liquid phase refrigerant (e _2a point → f _2a point and e _2a point → g _2a point). And the gaseous-phase refrigerant | coolant which flowed out from the gaseous-phase refrigerant | coolant exit of the accumulator 14 is suck | inhaled and compressed by the 1st compressor 11 via the 3rd three-way coupling 17c (point _f2a- > _a2a ).

On the other hand, the liquid-phase refrigerant that has flowed out from the outlet of the liquid-phase refrigerant of the accumulator 14 is further decompressed and expanded in an isoenthalpy manner at the low-pressure side fixed throttle 15 to reduce its pressure (point g _2a → point h _2a ). The refrigerant decompressed and expanded by the low-pressure side fixed throttle 15 flows into the use-side heat exchanger 51 through the electric four-way valve 31, and absorbs heat from the internal air circulated by the blower fan 51a to evaporate. (H _2a point → i _2a point).

Thereby, the internal air which is a fluid for heat exchange is cooled. That is, in the cooling operation mode of the present embodiment, the use side heat exchanger 51 functions as an evaporator. The refrigerant flowing out from the use side heat exchanger 51 is sucked into the second compressor 21 and compressed through the second electric three-way valve 33 and the first three-way joint 17a (i _2a point → j _2a point).

  At this time, the control device controls the operations of the first and second electric motors 11b and 21b so that the COP of the ejector refrigeration cycle as a whole approaches a maximum. Specifically, in order to improve the mechanical efficiency of the first and second compression mechanisms 11a and 21a, the first and second compression mechanisms 11a and 21a are controlled so that the pressure increase amounts are substantially equal.

  Note that the compression efficiency means that the increase amount ΔH1 is actually calculated when the increase amount of the enthalpy of the refrigerant when the refrigerant is isentropically compressed by the first and second compressors 11 and 21 is ΔH1. 1 and a value obtained by dividing the refrigerant by the enthalpy increase ΔH2 of the refrigerant when the refrigerant is pressurized by the second compressors 11 and 21.

  For example, when the rotation speed and the pressure increase amount (pressure difference between the discharge pressure and the suction pressure) of the first and second compressors 11 and 21 increase, the temperature of the refrigerant rises due to the frictional heat, and the actual enthalpy increase ΔH2 Increases the compression efficiency.

Further, as described above, the refrigerant discharged from the second compressor 21 is sucked into the ejector 13 from the refrigerant suction port 13b via the third electric three-way valve 34 (j _2a point → d _2a point). .

  Next, the heating operation mode will be described. The heating operation mode is executed when the heating operation mode is selected by the mode switching switch in a state where the operation switch of the operation panel is turned on. In the heating operation mode, the control device activates the first and second electric motors 11b and 21b, the blower fans 41a and 51a, and the electric four-way valve 31 and the first to third electric three-way valves 32 to 34 are broken lines. Switch to the circuit indicated by the arrow.

Therefore, the refrigerant (point a _{2b in} FIG. 2B) compressed by the first compressor 11 flows into the use side heat exchanger 51 via the electric four-way valve 31, and circulates from the blower fan 51a. The heat is exchanged with the blown-in chamber air to dissipate heat and condense (a _2b point → b _2b point). That is, in the heating operation mode of the present embodiment, the use side heat exchanger 51 functions as a radiator, and the internal air is heated.

The refrigerant radiated by the use-side heat exchanger 51 flows into the high-pressure side fixed throttle 12 via the second electric three-way valve 33 and is decompressed and expanded in an enthalpy manner until reaching an intermediate pressure (b _2b point → c _2b points). The refrigerant expanded under reduced pressure by the high-pressure side fixed throttle 12 flows into the accumulator 14 via the second three-way joint 17b, and is separated into a gas phase refrigerant and a liquid phase refrigerant (c _2b point → f _2b point and c _2b Point → g _2b ).

The liquid-phase refrigerant that has flowed out of the liquid-phase refrigerant outlet of the accumulator 14 is further decompressed and expanded in an isoenthalpy manner at the low-pressure side fixed throttle 15 to become a low-pressure refrigerant (point g _2b → point h _2b ). Then, the refrigerant decompressed and expanded by the low pressure side fixed throttle 15 flows into the outdoor heat exchanger 41 through the electric four-way valve 31, and absorbs heat from the blown air (outside air) blown by the blower fan 41a. It evaporates (h _2a point → i _2a point).

That is, in the heating operation mode of the present embodiment, the outdoor heat exchanger 41 functions as an evaporator. Then, the refrigerant that has flowed out of the outdoor heat exchanger 41 is sucked into the second compressor 21 through the first electric three-way valve 32 and the first three-way joint 17a and compressed until it reaches an intermediate pressure (i _2b Point → j _2b ).

The refrigerant discharged from the second compressor 21 flows into the third three-way joint 17c via the third electric three-way valve 34, and joins the gas-phase refrigerant flowing out of the accumulator 14 (j _2b point → f ′ _2b point). And f _2b point → f ′ _2b point). The refrigerant merged at the third three-way joint 17c is sucked into the first compressor 11 and compressed (f ′ _2b point → a _2b point).

  Other operations are the same as those in the cooling operation mode. Therefore, when the ejector refrigeration cycle 100 of this embodiment is operated, the following excellent effects can be obtained.

  First, in the cooling operation mode, the outdoor heat exchanger 41 is caused to function as a radiator, the refrigerant radiated by the outdoor heat exchanger 41 is caused to flow into the nozzle portion 13a of the ejector 13, and the use side heat exchanger 51 is evaporated. An ejector-type refrigeration cycle is configured to function as a container and suck the refrigerant evaporated in the use-side heat exchanger 51 from the refrigerant suction port 13b of the ejector 13. Thereby, the internal air in the cold storage can be cooled.

  In this cooling operation mode, since the second compression mechanism 21a is provided, the pressure difference between the high-pressure refrigerant and the low-pressure refrigerant decreases, for example, at a low outside air temperature, and the drive flow of the ejector 13 is reduced. Even if the operation condition is such that the flow rate is reduced, that is, the suction condition of the ejector 13 is reduced, the suction ability of the ejector 13 can be assisted by the suction and discharge action of the second compression mechanism 21a.

  Furthermore, in the cooling operation mode of the present embodiment, the liquid refrigerant can be reliably supplied from the accumulator 14 to the use side heat exchanger 51 by the suction action of the second compression mechanism 21a. As a result, in the cooling operation mode in which the ejector refrigeration cycle is configured, it is possible to stably operate the ejector refrigeration cycle 100 by suppressing a decrease in the flow rate of the drive flow of the ejector 13.

  Furthermore, since the pressure of the refrigerant can be increased by the pressure-increasing action of the two first and second compression mechanisms 11a and 21a and the diffuser portion 13d of the ejector 13, the first and second compression mechanisms can be increased with respect to the case where the pressure is increased by one compression mechanism. 2 COP can be improved by reducing the driving power of the compression mechanisms 11a and 21a.

  That is, the driving power of the first compression mechanism 11a can be reduced by increasing the suction pressure of the first compression mechanism 11a by the pressure increasing action of the diffuser portion 13d. Furthermore, since the pressure difference between the suction pressure and the discharge pressure in the first and second compression mechanisms 11a and 21a can be reduced, the compression efficiency of the first and second compression mechanisms 11a and 21a can be improved.

  At this time, since the first and second electric motors 11b and 21b can independently change the refrigerant discharge capacities of the first and second compression mechanisms 11a and 21a, the COP of the ejector refrigeration cycle 100 as a whole is effectively improved. Can be improved.

  In the heating operation mode, the use-side heat exchanger 51 functions as a radiator, and the refrigerant radiated by the use-side heat exchanger is decompressed by the high-pressure side fixed throttle 12 and flows into the accumulator 14. And the refrigerant discharged from the second compression mechanism 21a are combined and sucked into the first compression mechanism 11a.

  That is, in this heating operation mode, a so-called economizer-type refrigeration cycle that boosts the refrigerant in multiple stages is configured, and the air in the cold storage can be heated. Further, by configuring the economizer refrigeration cycle, the pressure between the suction refrigerant pressure and the discharge refrigerant pressure in each of the first and second compression mechanisms 11a and 12a is higher than when the pressure of the refrigerant is increased by a single compression means. By reducing the difference, the compression efficiency of each compression mechanism can be improved.

  Further, since the first compression mechanism 11a can suck the refrigerant obtained by combining the gas-phase refrigerant separated by the accumulator 14 and the refrigerant discharged from the second compression mechanism 21a, only the refrigerant discharged from the second compression mechanism 21a is sucked. In contrast, the enthalpy of the refrigerant sucked into the first compression mechanism 11a can be reduced. Accordingly, it is possible to improve the COP by reducing the amount of compression work when the first compression mechanism 11a compresses the refrigerant in an isentropic manner.

  Therefore, even in the heating operation mode, the cycle can be stably operated while exhibiting a high COP.

  Thus, the ability to operate the ejector refrigeration cycle stably while exhibiting high COP is a refrigeration cycle apparatus having a large pressure difference between the high-pressure refrigerant and the low-pressure refrigerant, for example, the internal temperature is extremely low during the cooling operation mode. It is extremely effective when applied to a cold storage cabinet or the like used in an environment where the outside air as the heat absorption source is at a very low temperature in the heating operation mode.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows.

  (1) In the above-described embodiment, an example of switching to the refrigerant flow path constituting the ejector refrigeration cycle during the cooling operation mode and switching to the refrigerant flow path constituting the economizer refrigeration cycle during the heating operation mode, that is, the cooling operation In the example, the mode corresponds to one operation mode described in the claims, and the heating operation mode corresponds to the other operation mode described in the claims. Also good.

  That is, during the cooling operation mode, switching to the refrigerant flow path constituting the economizer refrigeration cycle, and during the heating operation mode, switching to the refrigerant flow path constituting the ejector refrigeration cycle, that is, the heating operation mode is described in the claims. The cooling operation mode may correspond to the other operation mode described in the claims.

  (2) In the above-described embodiment, the first and second compressors 11 and 21 have been described as adopting separate compressors. However, the first and second compression mechanisms 11a and 21a and The first and second electric motors 11b and 21b may be configured integrally.

  For example, the first and second compression mechanisms 11a and 21a and the first and second electric motors 11b and 21b may be accommodated in the same housing and integrally configured. In this case, the rotation shafts of the first and second compression mechanisms 11a and 21a may be shared, and both compression mechanisms may be driven by a driving force supplied from a common drive source.

  Thereby, the 1st, 2nd compression mechanism 11a, 21a can be reduced in size, and size reduction as the whole ejector-type refrigerating cycle can be achieved.

  (3) In the above-described embodiment, the example in which the electric compressor is adopted as the first and second compressors 11 and 21 has been described. However, the format of the first and second compressors 11 and 21 is not limited to this. .

  For example, you may employ | adopt the variable capacity type compressor which can adjust a refrigerant | coolant discharge capability with the change of discharge capacity | capacitance by using an engine etc. as a drive source. In this case, the discharge capacity changing means becomes the discharge capacity changing means. Moreover, you may use the fixed capacity type compressor which adjusts a refrigerant | coolant discharge capability by changing the connection with a drive source intermittently by the interruption of an electromagnetic clutch. In this case, the electromagnetic clutch becomes the discharge capacity changing means.

  Further, the first and second compressors 11 and 21 may employ the same type of compression mechanism or different types of compression mechanisms.

  (4) In the above-described embodiment, the fixed ejector 13 in which the throttle passage area of the nozzle portion 13a is fixed is adopted as the ejector 13. However, the variable ejector configured to be able to change the throttle passage area of the nozzle portion. May be adopted. Further, in each of the above-described embodiments, the high-pressure side fixed throttle 12 is employed as the high-pressure side pressure reducing means, but, of course, a variable throttle mechanism may be employed.

  (5) In the above-described embodiment, an example in which a normal chlorofluorocarbon refrigerant is employed as the refrigerant has been described. However, the type of refrigerant is not limited to this. For example, hydrocarbon refrigerant, carbon dioxide, etc. may be used. Furthermore, the ejector refrigeration cycle of the present invention may be configured as a supercritical refrigeration cycle in which the high-pressure side refrigerant pressure exceeds the critical pressure of the refrigerant.

  Furthermore, when configuring a supercritical refrigeration cycle, as a high pressure side decompression means, a pressure that is adjusted to a target high pressure that is determined so that the COP becomes substantially maximum based on the outlet side refrigerant temperature of the heat exchanger that functions as a radiator. A control valve may be employed.

  As such a pressure control valve, specifically, it has a temperature sensing part provided on the heat exchanger outlet side that functions as a radiator, and a heat exchanger outlet that functions as a radiator inside the temperature sensing part. It is possible to adopt a configuration in which a pressure corresponding to the temperature of the side refrigerant is generated, and the valve opening is adjusted by a mechanical mechanism by a balance between the internal pressure of the temperature sensing unit and the refrigerant pressure on the outlet side of the heat exchanger functioning as a radiator.

  (6) In the above-described embodiments, the example in which the electric four-way valve 31 and the first to third electric three-way valves 32 to 34 are employed as the refrigerant flow path switching means has been described. However, the present invention is not limited to this.

  For example, as shown in FIG. 3A, instead of the electric four-way valve 31, two electric three-way valves 31a may be combined, and as shown in FIG. You may comprise combining the on-off valve (electromagnetic valve) 31b. Moreover, as shown to Fig.4 (a), you may comprise combining the three on-off valves (electromagnetic valve) 32b instead of the 1st-3rd electric three-way valves 32-34.

  (7) In the above-described embodiment, the fixed throttle is adopted as the high pressure side pressure reducing means and the low pressure side pressure reducing means, but as the high pressure side pressure reducing means and the low pressure side pressure reducing means, the refrigerant is volume expanded to reduce the pressure, You may employ | adopt the expander which converts the pressure energy of a refrigerant | coolant into mechanical energy, and outputs it.

  As such an expander, specifically, a volume type compression means such as a scroll type, a vane type, or a rolling piston type can be employed. Then, by flowing the refrigerant so that it flows backward with respect to the refrigerant flow when the positive displacement compression means is used as the compression means, mechanical energy can be output while the refrigerant is volume-expanded and depressurized.

  (8) In each of the above-described embodiments, the example in which the ejector-type refrigeration cycle 100 of the present invention is applied to a cold storage is described, but the application of the present invention is not limited to this. For example, the ejector refrigeration cycle may be applied to an air conditioner, another stationary refrigeration cycle apparatus, a vehicle refrigeration cycle apparatus, or the like.

DESCRIPTION OF SYMBOLS 11, 21 1st, 2nd compressor 11a, 21a 1st, 2nd compression mechanism 11b, 21b 1st, 2nd electric motor 12 High pressure side fixed throttle 13 Ejector 13a Nozzle part 13b Refrigerant suction port 13d Diffuser part 14 Accumulator 15 Low pressure side fixed throttle 31 Electric four-way valve 32-34 First to third electric three-way valve 41 Outdoor heat exchanger 51 User side heat exchanger

Claims (5)

First and second compression mechanisms (11a, 21a) for compressing and discharging the refrigerant;
An outdoor heat exchanger (41) for exchanging heat between the refrigerant and the outside air;
A use side heat exchanger (51) for exchanging heat between the refrigerant and the fluid to be heat exchanged;
The refrigerant sucked from the refrigerant suction port (13b) by the flow of the high-speed jet refrigerant jetted from the nozzle part (13a) for decompressing and expanding the refrigerant, and sucked from the jetted refrigerant and the refrigerant suction port (13b) An ejector (13) for increasing the pressure of the refrigerant mixed with the refrigerant at the diffuser section (13d);
High pressure side decompression means (12) for decompressing and expanding the refrigerant;
The gas-liquid of the refrigerant flowing out from the diffuser section (13d) or the refrigerant flowing out from the high-pressure side pressure reducing means (12) is separated, and the separated gas-phase refrigerant is moved to the suction port side of the first compression mechanism (11a). A gas-liquid separator (14) to be discharged;
Low pressure side decompression means (15) for decompressing and expanding the liquid refrigerant separated in the gas-liquid separator (14);
Refrigerant flow path switching means (31, 32, 33, 34) for switching the refrigerant flow path in the cooling operation mode for cooling the heat exchange target fluid and the refrigerant flow path in the heating operation mode for heating the heat exchange target fluid; With
The refrigerant flow path switching means (31-34)
In one of the cooling operation mode and the heating operation mode, the refrigerant discharged from the first compression mechanism (11a) in the outdoor heat exchanger (41) and the use side heat exchanger (51) is radiated. The refrigerant that has flowed out of the heat exchanger is caused to flow into the nozzle portion (13a), and the low-pressure-side decompression means (15) outflow refrigerant in the outdoor heat exchanger (41) and the use-side heat exchanger (51). The refrigerant that has flowed out of the heat exchanger that evaporates the refrigerant is switched to a refrigerant flow path that is sucked into the second compression mechanism (21a) and discharged to the refrigerant suction port (13b) side,
During the other operation mode of the cooling operation mode and the heating operation mode, the refrigerant discharged from the first compression mechanism (11a) of the outdoor heat exchanger (41) and the use side heat exchanger (51) is radiated. The refrigerant that has flowed out of the heat exchanger flows into the high-pressure side decompression means (12), and the low-pressure side decompression means (15) of the outdoor heat exchanger (41) and the use-side heat exchanger (51). The refrigerant flowing out from the heat exchanger that evaporates the refrigerant flowing out is switched to a refrigerant flow path that is sucked into the second compression mechanism (21a) and discharged to the suction port side of the first compression mechanism (11a). Ejector refrigeration cycle. Further, the refrigerant flow switching means (31 to 34) includes:
During the cooling operation mode, the refrigerant discharged from the first compression mechanism (11a) flows into the outdoor heat exchanger (41) to dissipate heat, and the low pressure side decompression means (15) discharges the refrigerant out of the use side heat exchanger. (51) is switched to the refrigerant flow path that is caused to flow and evaporate,
During the heating operation mode, the refrigerant discharged from the first compression mechanism (11a) flows into the use side heat exchanger (51) to dissipate heat, and the low pressure side decompression means (15) discharges the refrigerant out of the outdoor heat exchanger. The ejector-type refrigeration cycle according to claim 1, wherein the refrigerant flow path is switched to a refrigerant flow path that flows into (41) and evaporates. First discharge capacity changing means (11b) for changing the refrigerant discharge capacity of the first compression mechanism (11a);
Second discharge capacity changing means (21b) for changing the refrigerant discharge capacity of the second compression mechanism (21a);
The first discharge capacity changing means (11b) and the second discharge capacity changing means (21b) independently change the refrigerant discharge capacity of the first compression mechanism (11a) and the second compression mechanism (21a). The ejector refrigeration cycle according to claim 1, wherein the ejector refrigeration cycle is configured to be possible.   The said 1st compression mechanism (11a) and the said 2nd compression mechanism (21a) are accommodated in the same housing, and are comprised integrally, The one of Claims 1 thru | or 3 characterized by the above-mentioned. The ejector-type refrigeration cycle described in 1.   The ejector-type refrigeration cycle according to any one of claims 1 to 4, wherein the first compression mechanism (11a) increases the pressure of the refrigerant until it reaches a critical pressure or more.

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