JP2009222357A - Refrigeration device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress frost formation on an evaporator in an air conditioner (1) using a nonazeotropic mixture refrigerant. <P>SOLUTION: The evaporator is composed of a pre-stage evaporator (15a) for evaporating refrigerant expanded by a first expansion valve (14a), a post-stage evaporator (15b) for further evaporating the refrigerant evaporated by the pre-stage evaporator (15a). A connection pipe (16) for connecting the pre-stage evaporator (15a) and the post-stage evaporator (15b) is provided with a second expansion valve (14b) for decompressing the refrigerant flowing from the pre-stage evaporator (15a) to the post-stage evaporator (15b). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

    The present invention relates to a refrigeration apparatus including a refrigerant circuit that performs a refrigeration cycle using a non-azeotropic refrigerant mixture.

    2. Description of the Related Art Conventionally, a refrigeration apparatus including a refrigerant circuit that performs a refrigeration cycle using a non-azeotropic refrigerant as a refrigerant is known (see, for example, Patent Document 1). FIG. 12 is a refrigerant circuit diagram of a conventional air conditioner as an example of a refrigeration apparatus, and FIG. 13 is a refrigeration in a conventional air conditioner on a TS (temperature-entropy) diagram of a non-azeotropic refrigerant mixture. It is the figure which showed the cycle.

    As shown in FIG. 12, the refrigerant circuit (51) in the conventional air conditioner (50) includes a compressor (53), a four-way switching valve (54), an indoor heat exchanger (55), and an expansion valve (56). And an outdoor heat exchanger (57). The air conditioner (50) can perform a cooling / heating operation by being configured to be able to reverse the circulation direction of the refrigerant by the switching operation of the four-way switching valve (54).

    In the heating operation of the air conditioner (50), the four-way switching valve (54) is set as shown by a solid line in FIG. When the compressor (53) is operated in this state, the indoor heat exchanger (55) becomes a condenser, and the outdoor heat exchanger (57) becomes an evaporator to perform a refrigeration cycle.

The high-pressure refrigerant discharged from the compressor (53) passes through the four-way switching valve (54) (point d2 in FIGS. 12 and 13), flows into the indoor heat exchanger (55), and dissipates heat to the room air. Condensation (point d3 in FIGS. 12 and 13). The condensed high-pressure refrigerant is decompressed by the expansion valve (56) to become a low-pressure refrigerant (point d4 in FIGS. 12 and 13) and flows into the outdoor heat exchanger (57). The low-pressure refrigerant that has flowed into the outdoor heat exchanger (57) absorbs heat from the outdoor air and evaporates. The evaporated low-pressure refrigerant passes through the four-way switching valve (54) (point d1 in FIGS. 12 and 13) and is sucked into the compressor (53). The sucked low-pressure refrigerant is compressed and discharged again as a high-pressure refrigerant. By repeating this operation, heating operation of the air conditioner (50) is performed.
JP 2000-161805 A

    By the way, as can be seen from FIG. 13, in the refrigeration cycle, the refrigerant inlet temperature (T1) of the outdoor heat exchanger (evaporator) is the lowest. The reason why the refrigerant inlet temperature of the outdoor heat exchanger becomes lower than the refrigerant outlet temperature is that, unlike a single refrigerant, the non-azeotropic refrigerant mixture undergoes a phase change with a temperature change.

    Therefore, for example, during the heating operation of the air conditioner, when the outside air temperature is low, such as in winter, frost formation is likely to occur at the refrigerant inlet portion of the outdoor heat exchanger.

    This invention is made | formed in view of this point, The objective is to suppress the frost formation to an evaporator in the freezing apparatus using a non-azeotropic refrigerant mixture.

    The first invention has a refrigerant circuit (10) in which a compression mechanism (12), a condenser (11), an expansion mechanism (14a), and an evaporator (15) are connected, and the refrigerant circuit (10) is provided. A refrigeration apparatus that performs a refrigeration cycle by reversibly circulating a non-azeotropic refrigerant mixture is assumed. Then, the refrigerant circuit (10) causes the refrigerant (15) during evaporation of the evaporator (15) to be supplied once during the refrigeration cycle in which the condenser (11) is on the use side and the evaporator (15) is on the heat source side. Alternatively, a pressure reduction mechanism (14b) for reducing pressure stepwise a plurality of times is provided.

    In the first aspect of the invention, the refrigeration apparatus is configured as a switchable cooling / heating cycle such as an air conditioner. And unlike the conventional refrigeration apparatus, in this refrigeration apparatus, in the refrigeration cycle (that is, in the heating cycle) in which the condenser (11) is on the use side and the evaporator (15) is on the heat source side, the evaporator (15 ) In the middle of evaporation is depressurized, and the temperature of the refrigerant decreases. Thereby, when it is going to secure the evaporation capability similar to the past, a refrigerant | coolant can be evaporated by the pressure higher than before in the entrance side of an evaporator (15) by the part for the fall of refrigerant | coolant temperature. Therefore, the refrigeration apparatus of the present invention can evaporate the refrigerant at a temperature higher than the refrigerant inlet temperature of the evaporator in the conventional refrigeration apparatus.

    The second invention has a refrigerant circuit (10) in which a compression mechanism (12), a condenser (11) on the use side, an expansion mechanism (14a), and an evaporator (15) on the heat source side are connected in order, It is premised on a refrigeration apparatus that performs a refrigeration cycle by circulating a non-azeotropic refrigerant mixture through the refrigerant circuit (10). And the said refrigerant circuit (10) is provided with the pressure reduction mechanism (14b) for pressure-reducing the refrigerant in the middle of the evaporation of the said evaporator (15) in steps of 1 time or several times.

    In the second invention, the refrigeration apparatus is configured as a dedicated heating cycle machine such as a water heater or floor heating. And unlike the conventional freezing apparatus, in this freezing apparatus, the refrigerant | coolant in the middle of evaporation of the evaporator (15) which is a heat source side is pressure-reduced, and the temperature of the refrigerant | coolant falls. Thereby, when it is going to secure the evaporation capability similar to the past, a refrigerant | coolant can be evaporated by the pressure higher than before in the entrance side of an evaporator (15) by the part for the fall of refrigerant | coolant temperature. Therefore, the refrigeration apparatus of the present invention can evaporate the refrigerant at a temperature higher than the refrigerant inlet temperature of the evaporator in the conventional refrigeration apparatus.

    The third invention has a refrigerant circuit (10) in which a compression mechanism (12), a heat source side condenser (11), an expansion mechanism (14a), and a utilization side evaporator (15) are connected in order, It is premised on a refrigeration apparatus that performs a refrigeration cycle by circulating a non-azeotropic refrigerant mixture through the refrigerant circuit (10). And the said refrigerant circuit (10) is provided with the pressure reduction mechanism (14b) for pressure-reducing the refrigerant in the middle of the evaporation of the said evaporator (15) in steps of 1 time or several times.

    In the third invention, the refrigeration apparatus is configured as a dedicated cooling cycle machine such as a refrigeration container or a chiller. And unlike the conventional freezing apparatus, in this freezing apparatus, the refrigerant | coolant in the middle of evaporation of the evaporator (15) which is a utilization side is pressure-reduced, and the temperature of the refrigerant | coolant falls. Thereby, when it is going to secure the evaporation capability similar to the past, a refrigerant | coolant can be evaporated by the pressure higher than before in the entrance side of an evaporator (15) by the part for the fall of refrigerant | coolant temperature. Therefore, the refrigeration apparatus of the present invention can evaporate the refrigerant at a temperature higher than the refrigerant inlet temperature of the evaporator in the conventional refrigeration apparatus.

    In a fourth aspect based on the first aspect, the temperature of the refrigerant when the evaporator (15) on the heat source side frosts is set as a lower limit temperature, and the inlet refrigerant temperature of the evaporator (15) is Control means (4) for controlling the expansion mechanism (14a) is provided so as not to fall below the lower limit temperature.

    In the fourth invention, by adjusting the expansion mechanism (14a), at least the inlet refrigerant temperature of the evaporator (15) is controlled to be equal to or higher than the lower limit temperature.

    According to a fifth invention, in the first invention, the control means (4) for controlling the decompression mechanism (14b) so that the outlet refrigerant temperature of the evaporator (15) on the heat source side becomes a predetermined target value. It is equipped with.

    In the fifth invention, by adjusting the decompression mechanism (14b), for example, the outlet refrigerant temperature of the evaporator (15) (that is, the suction temperature of the compression mechanism (12)) is controlled with a predetermined degree of superheat.

    According to a sixth invention, in the first invention, the temperature of the refrigerant when the evaporator (15) on the heat source side frosts is set as a lower limit temperature, and the evaporator (15) on the heat source side A predetermined target value of the outlet refrigerant temperature of the refrigerant is set as an upper limit temperature, and the pressure reducing mechanism is such that the refrigerant temperature in the course of evaporation of the evaporator (15) does not exceed the upper limit temperature and does not fall below the lower limit temperature. Control means (4) for controlling (14b) is provided.

    In the sixth aspect of the invention, the refrigerant temperature in the evaporator (15) is suppressed to a target outlet temperature or lower. Furthermore, even if the refrigerant in the evaporator (15) is depressurized by the depressurization mechanism (14b), the refrigerant temperature does not fall below the lower limit temperature.

    According to a seventh invention, in the second or third invention, the temperature of the refrigerant when the evaporator (15) frosts is set as a lower limit temperature, and the inlet refrigerant temperature of the evaporator (15) is Control means (4) for controlling the expansion mechanism (14a) is provided so as not to fall below the lower limit temperature.

    In the seventh invention, by adjusting the expansion mechanism (14a), at least the inlet refrigerant temperature of the evaporator (15) is controlled to be equal to or higher than the lower limit temperature.

    The eighth invention is the control means (4) for controlling the pressure reducing mechanism (14b) so that the outlet refrigerant temperature of the evaporator (15) becomes a predetermined target value in the second or third invention. It is equipped with.

    In the eighth invention, by adjusting the decompression mechanism (14b), for example, the outlet refrigerant temperature of the evaporator (15) (that is, the suction temperature of the compression mechanism (12)) is controlled at a predetermined degree of superheat.

    According to a ninth invention, in the second or third invention, the temperature of the refrigerant when the evaporator (15) frosts is set as a lower limit temperature, and the outlet refrigerant of the evaporator (15) A predetermined target value of the temperature is set as an upper limit temperature, and the pressure reducing mechanism (14b) so that the refrigerant temperature during the evaporation of the evaporator (15) does not exceed the upper limit temperature and does not fall below the lower limit temperature. Is provided with control means (4) for controlling.

    In the ninth invention, the refrigerant temperature in the evaporator (15) is suppressed to a target outlet temperature or lower. Furthermore, even if the refrigerant in the evaporator (15) is depressurized by the depressurization mechanism (14b), the refrigerant temperature does not fall below the lower limit temperature.

    According to a tenth aspect of the present invention, in any one of the first, fourth to sixth aspects, the heat source side evaporator (15) is a pre-stage evaporator in which the refrigerant expanded by the expansion mechanism (14a) evaporates. (15a) and a post-stage evaporator (15b) that is connected to the pre-stage evaporator (15a) via a connection pipe (16) and further evaporates the refrigerant evaporated in the pre-stage evaporator (15a). Yes. The decompression mechanism (14b) is provided in the connection pipe (16).

    In the tenth invention, during the heating cycle, the refrigerant flowing through the upstream evaporator (15a) can be evaporated at a pressure higher than that of the downstream evaporator (15b). Therefore, in the evaporator (15), the refrigerant can be evaporated at a temperature higher than the refrigerant inlet temperature of the evaporator in the conventional refrigeration apparatus.

    An eleventh aspect of the present invention is the evaporator according to any one of the second, third, and seventh to ninth aspects, wherein the evaporator (15) is a pre-stage evaporator in which the refrigerant expanded by the expansion mechanism (14a) evaporates. (15a) and a post-stage evaporator (15b) that is connected to the pre-stage evaporator (15a) via a connection pipe (16) and further evaporates the refrigerant evaporated in the pre-stage evaporator (15a). Yes. The decompression mechanism (14b) is provided in the connection pipe (16).

    In the eleventh aspect of the invention, the refrigerant flowing through the upstream evaporator (15a) can be evaporated at a higher pressure than the downstream evaporator (15b). Therefore, in the evaporator (15), the refrigerant can be evaporated at a temperature higher than the refrigerant inlet temperature of the evaporator in the conventional refrigeration apparatus.

    In a twelfth aspect based on the tenth or eleventh aspect, the expansion mechanism is configured to evaporate in the drive channel (21a) through which the refrigerant condensed in the condenser (11) flows and in the rear stage evaporator (15b). A suction flow path (21b) that is sucked by the high-pressure refrigerant that flows through the drive flow path (21a), a refrigerant that flows through the suction flow path (21b), and a refrigerant that flows through the drive flow path (21a). It comprises an ejector channel (21c) that jets together and ejects, and an ejector (21). The refrigerant circuit (10) separates the refrigerant ejected from the ejection channel (21c) of the ejector (21) into a liquid refrigerant and a gas refrigerant, and the separated liquid refrigerant is the former stage evaporator (15a). And an ejector gas-liquid separator (22) configured to flow to the liquid side end of the compressor and the separated gas refrigerant to the suction side of the compression mechanism (12).

    In the twelfth aspect of the invention, the refrigerant flowing through the pre-stage evaporator (15a) is evaporated at a pressure higher than that of the post-stage evaporator (15b) even for the refrigerant circuit (10) having the ejector (21) and performing the ejector cycle. Can be made. Therefore, in the evaporator (15), the refrigerant can be evaporated at a temperature higher than the refrigerant inlet temperature of the evaporator in the conventional refrigeration apparatus.

    In a thirteenth aspect based on the tenth or eleventh aspect, the compression mechanism includes a low stage compressor (41b) that compresses the refrigerant evaporated in the rear stage evaporator (15b), and the low stage compressor ( And a high-stage compressor (41a) that further compresses the refrigerant compressed in 41b). The expansion mechanism includes a front stage expansion mechanism (43a) that expands the refrigerant condensed in the condenser (11), and a rear stage expansion mechanism (43b) that further expands the refrigerant expanded by the front stage expansion mechanism (43a). It is comprised by. The refrigerant circuit (45) separates the refrigerant expanded by the front stage expansion mechanism (43a) into a liquid refrigerant and a gas refrigerant, and the separated liquid refrigerant flows into the rear stage expansion mechanism (43b) and is separated. An expansion mechanism gas-liquid separator (42) is provided so that the subsequent gas refrigerant flows to the discharge pipe of the low-stage compressor (41b).

    In the thirteenth invention, a refrigerant circuit (45) having a high-stage and low-stage compressor (41a, 41b) and a front-stage and rear-stage expansion mechanism (43a, 43b) and performing a two-stage compression / two-stage expansion cycle is provided. In contrast, the refrigerant flowing through the former evaporator (15a) can be evaporated at a higher pressure than the latter evaporator (15b). Therefore, in the evaporator (15), the refrigerant can be evaporated at a temperature higher than the refrigerant inlet temperature of the evaporator in the conventional refrigeration apparatus.

In a fourteenth aspect based on any one of the first to thirteenth aspects, the non-azeotropic refrigerant mixture has a molecular formula 1: C ₃ H _m F _n (where m and n are integers of 1 or more and 5 or less) And the relationship of m + n = 6 is established.) And is a mixed refrigerant including a refrigerant having one double bond in the molecular structure.

In the fourteenth invention, the non-azeotropic mixed refrigerant filled in the refrigerant circuit (10) is a molecular formula 1: C ₃ H _m F _n (where m and n are integers of 1 to 5, and m + n = 6 And a refrigerant having one double bond in the molecular structure.

A fifteenth invention is represented by the molecular formula 1: C ₃ H _m F _n (where m and n are integers of 1 to 5 and the relationship m + n = 6 is established) in the fourteenth invention. And a refrigerant having one double bond in the molecular structure is 2,3,3,3-tetrafluoro-1-propene.

    In the fifteenth aspect, the non-azeotropic refrigerant mixture filled in the refrigerant circuit (10) contains 2,3,3,3-tetrafluoro-1-propene.

According to a sixteenth aspect, in the fourteenth or fifteenth aspect, the non-azeotropic refrigerant mixture is the molecular formula 1: C ₃ H _m F _n (where m and n are integers of 1 to 5, m + n = 6) and a refrigerant having one double bond in the molecular structure and difluoromethane.

    In the sixteenth aspect, a mixed refrigerant containing difluoromethane and a refrigerant represented by the molecular formula 1 and having one double bond in the molecular structure is used as the non-azeotropic refrigerant mixture. Here, the refrigerant represented by the molecular formula 1 and having one double bond in the molecular structure is a so-called low-pressure refrigerant. For this reason, for example, when a single refrigerant composed of a refrigerant represented by the molecular formula 1 and having one double bond in the molecular structure is used, the influence of the pressure loss of the refrigerant on the operation efficiency of the compressor is relatively small. The actual operating efficiency is relatively large compared to the theoretical operating efficiency. Therefore, in the present invention, difluoromethane, which is a so-called high-pressure refrigerant, is added to the refrigerant represented by the molecular formula 1 and having one double bond in the molecular structure.

In a seventeenth aspect based on any one of the fourteenth to sixteenth aspects, the non-azeotropic mixed refrigerant is the molecular formula 1: C ₃ H _m F _n (where m and n are 1 or more and 5 or less). It is an integer, and a relationship of m + n = 6 is established.) And a refrigerant mixture including pentafluoroethane and a refrigerant having one double bond in the molecular structure.

    In the seventeenth invention, a mixed refrigerant containing pentafluoroethane and a refrigerant represented by the above molecular formula 1 and having one double bond in the molecular structure is used as the non-azeotropic refrigerant mixture. Here, the refrigerant represented by the above-described molecular formula 1 and having one double bond in the molecular structure is a slightly flammable refrigerant, but it is not without the risk of ignition. Therefore, in the present invention, pentafluoroethane, which is a flame-retardant refrigerant, is added to the refrigerant represented by the above molecular formula 1 and having one double bond in the molecular structure.

    In an eighteenth aspect based on the fourteenth aspect, the non-azeotropic mixed refrigerant is a mixed refrigerant of HFC-32 and HFO-1225.

    In the eighteenth aspect of the invention, even for a refrigeration apparatus using a mixed refrigerant of HFC-32 and HFO-1225 as a non-azeotropic refrigerant mixture, the temperature is higher than the refrigerant inlet temperature of the evaporator in the conventional refrigeration apparatus. The refrigerant can be evaporated.

    In a nineteenth aspect based on the fourteenth aspect, the non-azeotropic refrigerant mixture is a refrigerant mixture of HFC-32 and HFO-1234.

    In the nineteenth aspect of the invention, even for a refrigeration system using a mixed refrigerant of HFC-32 and HFO-1234 as a non-azeotropic refrigerant mixture, the temperature is higher than the refrigerant inlet temperature of the evaporator in the conventional refrigeration apparatus. The refrigerant can be evaporated.

    In a twentieth aspect based on the nineteenth aspect, the HFO-1234 is the HFO-1234yf.

    In the twentieth invention, even for a refrigeration apparatus using a mixed refrigerant of HFC-32 and HFO-1234yf as a non-azeotropic refrigerant mixture, the temperature is higher than the refrigerant inlet temperature of the evaporator in the conventional refrigeration apparatus. The refrigerant can be evaporated.

    According to the first, second and third inventions, since the refrigerant in the middle of evaporation is decompressed in the evaporator (15), the temperature of the refrigerant in the middle of evaporation can be temporarily reduced. Therefore, the refrigerant can be evaporated at a higher pressure than before, that is, at a higher temperature than before, at the inlet side of the evaporator (15). As a result, the degree to which the refrigerant temperature becomes equal to or lower than the frosting temperature of the evaporator (15) in the evaporation process can be reduced. Therefore, the frost formation of the evaporator (15a, 15b) resulting from the use of the non-azeotropic refrigerant mixture can be suppressed.

    According to the fourth and seventh inventions, at least the inlet refrigerant temperature of the evaporator (15) can be reliably prevented from becoming lower than the frosting temperature of the evaporator (15). As a result, the degree to which the refrigerant temperature becomes equal to or lower than the frosting temperature of the evaporator (15) in the evaporation process can be further reduced. Therefore, frost formation of the evaporators (15a, 15b) can be further suppressed.

    According to the fifth and eighth inventions, at least the outlet refrigerant temperature of the evaporator (15) can be set to the predetermined target value. Therefore, the superheat degree control of the suction refrigerant of the compression mechanism (12) can be reliably performed. Therefore, a highly reliable refrigeration apparatus (10) can be provided.

    According to the sixth and ninth inventions, the temperature of the refrigerant is not less than the frosting temperature of the evaporator (15) of the evaporator (15) and not more than the target outlet refrigerant temperature of the evaporator (15) in the evaporation process. Can be controlled. Accordingly, the degree to which the refrigerant temperature becomes equal to or lower than the frosting temperature of the evaporator (15) can be surely reduced, and the temperature difference between, for example, air and the refrigerant that is the target of heat exchange can be increased. . As a result, it is possible to reliably earn the heat exchange amount in the evaporator (15) and ensure the evaporation capacity while preventing the evaporator (15) from frosting.

    According to the twelfth invention, the refrigerant can be evaporated in the evaporator (15) at a higher temperature than in the prior art. Therefore, in the refrigerant circuit (10) that performs the ejector cycle, it is possible to suppress frosting of the evaporators (15a, 15b) due to the use of the non-azeotropic refrigerant mixture.

    According to the thirteenth aspect, the refrigerant can be evaporated in the evaporator (15) at a higher temperature than in the prior art. Therefore, in the refrigerant circuit (45) that performs the two-stage compression / two-stage expansion cycle, it is possible to suppress frosting of the evaporators (15a, 15b) caused by using the non-azeotropic refrigerant mixture.

    According to the sixteenth aspect of the invention, difluoromethane, which is a so-called high-pressure refrigerant, is added to the refrigerant represented by the molecular formula 1 and having one double bond in the molecular structure. Thereby, the influence which the pressure loss of a refrigerant | coolant has on the compression efficiency of a compression mechanism (12) can be made small. As a result, driving efficiency can be improved.

    According to the seventeenth aspect of the invention, pentafluoroethane, which is a flame-retardant refrigerant, is added to the refrigerant represented by the above molecular formula 1 and having one double bond in the molecular structure. Thereby, a refrigerant | coolant can be made hard to burn.

    According to the eighteenth aspect of the present invention, the evaporator (15a, 15b) in the conventional refrigeration apparatus can be applied to a refrigeration apparatus using a mixed refrigerant of HFC-32 and HFO-1225 as the non-azeotropic refrigerant mixture. The refrigerant can be evaporated at a temperature higher than the refrigerant inlet temperature. Therefore, in the refrigeration apparatus using the mixed refrigerant of HFC-32 and HFO-1225, frosting of the evaporators (15a, 15b) due to the use of the non-azeotropic mixed refrigerant can be suppressed.

    According to the nineteenth aspect of the invention, the evaporator (15a, 15b) of the conventional refrigeration apparatus can be applied to a refrigeration apparatus that uses a mixed refrigerant of HFC-32 and HFO-1234 as the non-azeotropic refrigerant mixture. The refrigerant can be evaporated at a temperature higher than the refrigerant inlet temperature. Therefore, in the refrigeration apparatus using the mixed refrigerant of HFC-32 and HFO-1234, frosting of the evaporators (15a, 15b) due to the use of the non-azeotropic mixed refrigerant can be suppressed.

    According to the twentieth invention, the evaporator (15a, 15b) in the conventional refrigeration apparatus can be applied to a refrigeration apparatus using a mixed refrigerant of HFC-32 and HFO-1234yf as the non-azeotropic refrigerant mixture. The refrigerant can be evaporated at a temperature higher than the refrigerant inlet temperature. Therefore, in the refrigeration apparatus using the mixed refrigerant of HFC-32 and HFO-1234yf, frosting of the evaporators (15a, 15b) due to the use of the non-azeotropic mixed refrigerant can be suppressed.

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1
FIG. 1 is a refrigerant circuit diagram of an air-conditioning apparatus (refrigeration apparatus) (1) according to Embodiment 1 of the present invention. FIG. 2 is a diagram of the embodiment 1 on the TS diagram of a non-azeotropic refrigerant mixture. It is the figure which showed the heating cycle in an air conditioning apparatus (1).

    The refrigeration apparatus according to Embodiment 1 of the present invention is a separate type air conditioner including an outdoor unit (2) and an indoor unit (3). As shown in FIG. 1, the air conditioner (1) includes a refrigerant circuit (10) and a controller (4). The refrigerant circuit (10) is a closed circuit filled with a mixed refrigerant of HFC-32 (low boiling point component) and HFO-1234yf (high boiling point component) as a refrigerant, and can perform a cooling cycle and a heating cycle. It is configured.

    The refrigerant circuit (10) includes a use side circuit (10b) provided in the indoor unit (3) and a heat source side circuit (10a) provided in the outdoor unit (2). An indoor heat exchanger (11) is connected to the use side circuit (10b). The heat source side circuit (10a) includes a compressor (compression mechanism) (12), first and second four-way switching valves (13a, 13b), first and second expansion valves (14a, 14b), and first. , 2 outdoor heat exchangers (front evaporator, rear evaporator) (15a, 15b) are connected. The first expansion valve (14a) constitutes an expansion mechanism, and the second expansion valve (14b) constitutes a pressure reducing mechanism.

    Specifically, in the heat source side circuit (10a), the discharge side of the compressor (12) is the first port of the first four-way switching valve (13a), and the suction side of the compressor (12) is the first four-way path. Each is connected to the second port of the switching valve (13a). One end of the indoor heat exchanger (11) is connected to the third port of the second four-way switching valve (13b), and the other end of the indoor heat exchanger (11) is connected to the second four-way switching valve (13b). Each is connected to the fourth port.

    The third port of the first four-way selector valve (13a) and the first port of the second four-way selector valve (13b) are connected, and the fourth port of the first four-way selector valve (13a) The second port of the second four-way selector valve (13b) is connected by a refrigerant pipe. The refrigerant pipe has a first expansion valve (14a) and a first outdoor heat exchanger (15a) in order from the second four-way switching valve (13b) to the first four-way switching valve (13a). ), A second expansion valve (14b), and a second outdoor heat exchanger (15b).

    The compressor (12) is a variable capacity type so-called hermetically sealed type. The compressor (12) compresses the refrigerant sucked from the suction side and discharges it to the discharge side.

    The first four-way selector valve (13a) includes a first state (state indicated by a solid line in FIG. 1) in which the first port and the third port communicate with each other and the second port and the fourth port communicate with each other; Can be switched to a second state (state indicated by a broken line in FIG. 1) in which the second port and the fourth port communicate with each other and the second port and the third port communicate with each other. The second four-way selector valve (13b) includes a first state (state indicated by a solid line in FIG. 1) in which the first port communicates with the third port and the second port communicates with the fourth port; Can be switched to a second state (state indicated by a broken line in FIG. 1) in which the second port and the fourth port communicate with each other and the second port and the third port communicate with each other.

    The indoor heat exchanger (11) exchanges heat between indoor air taken in by an indoor fan (not shown) provided in the indoor unit (3) and refrigerant flowing through the refrigerant circuit (10). Make up the vessel. The first and second outdoor heat exchangers (15a, 15b) include outdoor air taken in by an outdoor fan (not shown) provided in the outdoor unit (2) and refrigerant flowing through the refrigerant circuit (10). An air heat exchanger for heat exchange is configured.

    Each of the first and second expansion valves (14a, 14b) is an electronic expansion valve having a variable opening.

    The controller (4) controls the operation of the refrigerant circuit (10) and constitutes a control means according to the present invention. The controller (4) includes starting, stopping and capacity control of the compressor (12), opening adjustment of the first and second expansion valves (14a, 14b), and first and second four-way switching valves (13a). , 13b). Detailed control operation of the controller (4) will be described later.

-Driving action-
<Cooling operation>
Next, the operation of the air conditioner (1) will be described.

    First, during the cooling operation, in FIG. 1, the first four-way switching valve (13a) is in the second state (broken line in FIG. 1), and the second four-way switching valve (13b) is in the second state (broken line in FIG. 1). Respectively. When the compressor (12) is operated in this state, the first and second outdoor heat exchangers (15a, 15b) serve as condensers, and the indoor heat exchanger (11) serves as an evaporator to perform a cooling cycle. Is called.

    As described above, the capacity of the compressor (12) and the opening degrees of the first and second expansion valves (14a, 14b) are appropriately adjusted by the controller (4). Here, the capacity of the compressor (12) is adjusted based on the low pressure of the refrigerant circuit (10). Further, the opening of the second expansion valve (14b) is set to be fully open, and only the opening of the first expansion valve (14a) is adjusted based on the suction superheat degree of the compressor (12).

    The high-pressure refrigerant discharged from the compressor (12) flows from the first port of the first four-way switching valve (13a) through the fourth port into the second outdoor heat exchanger (15b) and flows into the outdoor air. After condensing while dissipating heat, it flows out of the second outdoor heat exchanger (15b). The high-pressure refrigerant that has flowed out of the second outdoor heat exchanger (15b) flows through the second expansion valve (14b), flows into the first outdoor heat exchanger (15a), and is condensed while dissipating heat to the outdoor air. The first outdoor heat exchanger (15a) flows out. The high-pressure refrigerant that has flowed out of the first outdoor heat exchanger (15a) flows into the first expansion valve (14a), is decompressed to a predetermined pressure, becomes low-pressure refrigerant, and flows out of the first expansion valve (14a).

    The low-pressure refrigerant that has flowed out of the first expansion valve (14a) flows from the second port of the second four-way selector valve (13b) through the third port into the indoor heat exchanger (11), and from the indoor air. After evaporating while absorbing heat, it flows out of the indoor heat exchanger (11). Here, the indoor air is cooled by the heat absorption of the refrigerant. The low-pressure refrigerant that has flowed out of the indoor heat exchanger (11) is second from the fourth port of the second four-way selector valve (13b) to the first port and from the third port of the first four-way selector valve (13a). It is sucked into the compressor (12) through the port. The low-pressure refrigerant sucked into the compressor (12) is compressed to a predetermined pressure to become a high-pressure refrigerant, and is discharged from the compressor (12). The discharged high-pressure refrigerant flows again from the first port of the first four-way switching valve (13a) through the fourth port into the second outdoor heat exchanger (15b). As the refrigerant circulates in this way, a cooling operation is performed in the air conditioner (1).

<Heating operation>
During heating operation, as shown in FIG. 1, the first four-way selector valve (13a) is in the first state (solid line in FIG. 1), and the second four-way selector valve (13b) is in the first state (solid line in FIG. 1). ) Respectively. When the compressor (12) is operated in this state, the first and second outdoor heat exchangers (15a, 15b) serve as evaporators, and the indoor heat exchanger (11) serves as a condenser to perform a heating cycle. Is called.

    Here, in the controller (4), the capacity of the compressor (12) is adjusted based on the high pressure of the refrigerant circuit (10). The valve opening of the first expansion valve (14a) is adjusted based on the refrigerant inlet temperature of the first outdoor heat exchanger (15a), and the valve opening of the second expansion valve (14b) is based on the intake superheat degree. And adjust it.

    The high-pressure refrigerant discharged from the compressor (12) flows from the first port to the third port of the first four-way selector valve (13a) and from the first port to the third port of the second four-way selector valve (13b). (Point a2 in FIGS. 1 and 2), flows into the indoor heat exchanger (11), condenses while radiating heat to the indoor air, and then flows out of the indoor heat exchanger (11) (FIGS. 1 and 2). Point a3) in FIG. Here, the indoor air is heated by the heat radiation of the refrigerant. The high-pressure refrigerant that has flowed out of the indoor heat exchanger (11) flows into the first expansion valve (14a), is decompressed to a predetermined pressure, becomes an intermediate-pressure refrigerant, and flows out of the first expansion valve (14a) (see FIG. 1, point a4) in FIG. The intermediate pressure refrigerant that has flowed out of the first expansion valve (14a) flows into the first outdoor heat exchanger (15a), evaporates while absorbing heat from the outdoor air, and then passes through the first outdoor heat exchanger (15a). It flows out (point a5 in FIGS. 1 and 2).

    The intermediate-pressure refrigerant that has flowed out of the first outdoor heat exchanger (15a) flows into the second expansion valve (14b) and is further reduced to a predetermined pressure to become low-pressure refrigerant and flows out of the second expansion valve (14b). (Point a6 in FIGS. 1 and 2). The low-pressure refrigerant that has flowed out of the second expansion valve (14b) flows into the second outdoor heat exchanger (15b), evaporates while absorbing heat from the outdoor air, and then flows out of the second outdoor heat exchanger (15b). To do. The low-pressure refrigerant that has flowed out of the second outdoor heat exchanger (15b) passes through the second port from the fourth port of the first four-way switching valve (13a) (point a1 in FIGS. 1 and 2), and the compressor (12) Inhaled. The low-pressure refrigerant sucked into the compressor (12) is compressed to a predetermined pressure to become a high-pressure refrigerant, and is discharged from the compressor (12). The discharged high-pressure refrigerant passes through the third port from the first port of the first four-way switching valve (13a) and the third port from the first port of the second four-way switching valve (13b) (FIG. 1, FIG. 2 point a2) flows into the indoor heat exchanger (11). As the refrigerant circulates in this way, the heating operation is performed in the air conditioner (1).

<Control of each expansion valve>
Next, detailed control of the first expansion valve (14a) and the second expansion valve (14b) during the heating operation will be described with reference to FIGS. The points a1 and a4 to a6 shown in FIGS. 3 and 4 correspond to the points a1 and a4 to a6 shown in FIGS. 1 and 2, respectively. Moreover, the broken line shown in FIG.3 and FIG.4 shows the change of the conventional evaporation temperature using a non-azeotropic refrigerant mixture, Z1 shows the inlet_port | entrance refrigerant | coolant temperature of the conventional evaporator.

    In the controller (4), a target value for the outlet refrigerant temperature (point a1) of the evaporator (15) is set. Furthermore, the “lower limit temperature” and the “upper limit temperature” of the refrigerant in the evaporation process in the evaporator (15) are set in the controller (4). The “lower limit temperature” is the refrigerant temperature (frosting temperature shown in FIGS. 3 and 4) when the evaporator (15) frosts. The “upper limit temperature” is the same value as the target value of the outlet refrigerant temperature (the temperature of the alternate long and short dash line of Z2-a1 shown in FIGS. 3 and 4). That is, the one-dot chain line of Z2-a1 is the evaporation temperature (constant) when the azeotropic refrigerant mixture is used.

    Then, the controller (4) adjusts the opening of the first expansion valve (14a) so that the inlet refrigerant temperature (point a4) of the evaporator (15) becomes the “lower limit temperature”. Then, as shown in FIG. 3, when the refrigerant temperature in the evaporation process reaches the “upper limit temperature” (point a5), the controller (4) depressurizes the refrigerant and lowers the refrigerant temperature to the “lower limit temperature”. (Point a6), the opening degree of the second expansion valve (14b) is adjusted. Alternatively, as shown in FIG. 4, when the refrigerant temperature in the evaporation process reaches a predetermined temperature lower than the “upper limit temperature” (point a5), the controller (4) depressurizes the refrigerant and sets the refrigerant temperature to the “lower limit temperature”. The degree of opening of the second expansion valve (14b) may be adjusted so as to reduce the pressure to “2” (point a6).

    Thereby, it is possible to reliably avoid a state in which the refrigerant temperature in the evaporation process is lower than the frosting temperature of the evaporator (15). Furthermore, since the refrigerant temperature in the evaporation process is controlled so as not to exceed the “upper limit temperature”, a necessary temperature difference between the refrigerant and the outside air temperature can be ensured. Thereby, evaporation capability can be earned. In particular, as shown in FIG. 4, if the refrigerant is depressurized when the refrigerant temperature reaches a predetermined temperature lower than the “upper limit temperature”, the temperature difference between the refrigerant and the outside air temperature can be increased, and the evaporation capacity can be increased. Can earn more. Further, since the refrigerant temperature in the evaporation process is once lowered to the lower limit temperature, the temperature difference between the refrigerant and the outside air temperature can be greatly increased, and the evaporation ability can be further increased.

    In this embodiment, two evaporators (15a, 15b) are provided and one expansion valve (14b) is provided between them. However, three or more evaporators are provided in series, and each of the evaporators is provided. One expansion valve may be provided between each. For example, when three evaporators are connected in series, the state shown by thick dashed lines in FIGS. 3 and 4 is shown, and when four evaporators are connected in series, they are shown by thick broken lines in FIGS. 3 and 4. It becomes a state. Thus, the difference between the refrigerant temperature and the outside air temperature in the evaporation process can be increased as the number of evaporators and expansion valves is increased and the number of times of decompression is increased. As a result, the evaporation capability can be increased as shown in FIG. In FIG. 5, the vertical axis indicates the evaporation capacity, and the horizontal axis indicates the number of divisions of the evaporator (15) (that is, the number of evaporators). In FIG. 5, as in this embodiment, the case where two evaporators (15a, 15b) are provided is divided into one, and the evaporation capacity at that time is 100%.

-Effect of Embodiment 1-
According to the first embodiment, unlike the conventional air conditioner (50), the refrigerant flowing through the refrigerant circuit (10) can be decompressed by the expansion mechanism (14a) and the decompression mechanism (14b). Thereby, the refrigerant | coolant which flows through the said front stage evaporator (15a) can be evaporated by the pressure higher than the said back stage evaporator (15b). Therefore, as shown in FIG. 2, the refrigeration apparatus (1) of the present invention is higher than the refrigerant inlet temperature (T1 in FIGS. 2 and 13) of the evaporator (15a, 15b) in the conventional air conditioner (50). The refrigerant can be evaporated at a high temperature (T2 in FIG. 2), and frosting of the evaporator due to the use of the non-azeotropic refrigerant mixture can be suppressed.

<< Embodiment 2 >>
FIG. 3 is a refrigerant circuit diagram of an air conditioner (20) according to Embodiment 2 of the present invention, and FIG. 4 is an air conditioner (Embodiment 2) on a TS diagram of a non-azeotropic refrigerant mixture. It is the figure which showed the heating cycle in 20).

    The difference from the refrigerant circuit (10) of the air conditioner (1) shown in the first embodiment is that, instead of the first expansion valve (14a), the ejector (21), the ejector gas-liquid separator (22), and the heating And an on-off valve (24). That is, the heating cycle performed by the refrigerant circuit (10) of the air conditioner (20) constitutes an ejector cycle. In FIG. 3, the same parts as those of the air conditioner (1) of the first embodiment are denoted by the same reference numerals, and only differences will be described.

    The ejector (21) depressurizes and accelerates the driving fluid flowing into the ejector (21) with a nozzle provided in the ejector (21), and the suction fluid is ejected by the negative pressure generated by the acceleration. Aspirate inside. The ejector (21) mixes the suction fluid and the driving fluid to form a mixed fluid, and decelerates the pressure of the mixed fluid with a diffuser provided in the ejector (21), and ejects the mixed fluid. It is.

    Specifically, the ejector (21) is evaporated in the drive flow path (21a) through which the high-pressure refrigerant (driving fluid) condensed in the indoor heat exchanger (11) flows and in the second outdoor heat exchanger (15b). The suction flow path (21b) (21b) in which the low-pressure refrigerant (suction fluid) is sucked by the high-pressure refrigerant flowing in the drive flow path (21a), the refrigerant flowing in the suction flow path (21b), and the drive flow path ( And a jetting passage (21c) for jetting the refrigerant flowing through 21a). The drive channel (21a) is provided with the nozzle described above, and the ejection channel (21c) is provided with the diffuser described above. Note that the nozzle diameter may be configured to be variable by the controller (4). In this case, the pressure reduction amount of the driving fluid can be adjusted by changing the hole diameter of the nozzle.

    The ejector gas-liquid separator (22) separates the refrigerant ejected from the ejection channel (21c) of the ejector (21) into liquid refrigerant and gas refrigerant. Specifically, the gas-liquid separator for ejector (22) includes a gas-liquid separation container (22d) for storing liquid refrigerant and gas refrigerant, and a first for the refrigerant to flow into the gas-liquid separation container (22d). A port (22a), a second port (22c) through which liquid refrigerant after gas-liquid separation flows out, and a third port (22b) through which gas refrigerant flows out are provided.

    The heating on-off valve (24) is an electromagnetic valve that can be opened and closed by the controller (4).

    In the refrigerant circuit (10), a refrigerant pipe extending from the second port of the second four-way selector valve (13b) is connected to the drive channel (21a) of the ejector (21), and the first four-way A refrigerant pipe extending from the fourth port of the switching valve (13a) is connected to the third port (22b) of the ejector gas-liquid separator (22). The ejection flow path (21c) of the ejector (21) and the first port (22a) of the ejector gas-liquid separator (22) are connected by a refrigerant pipe (23), and the refrigerant pipe (23) The heating on-off valve (24) is provided.

    The second port (22c) of the gas-liquid separator for ejector (22) and the suction flow path (21b) of the ejector (21) are connected by a refrigerant pipe, and the gas-liquid separator for ejector ( A first outdoor heat exchanger (15a), a second expansion valve (14b), and a second outdoor heat exchanger (15b) are provided in this order from 22) to the ejector (21).

-Driving action-
<Cooling operation>
Next, the operation of the air conditioner (20) will be described.

    First, during cooling operation, as shown in FIG. 3, the first four-way selector valve (13a) is in the second state (broken line in FIG. 3), and the second four-way selector valve (13b) is in the second state (FIG. 3). Are respectively set to broken lines). Further, the heating on-off valve (24) is closed. When the compressor (12) is operated in this state, the first and second outdoor heat exchangers (15a, 15b) serve as condensers, and the indoor heat exchanger (11) serves as an evaporator to perform a cooling cycle. Is called. The capacity of the compressor (12) is adjusted by the controller (4) based on the low pressure of the refrigerant circuit (10).

    The high-pressure refrigerant discharged from the compressor (12) passes through the first port to the fourth port of the first four-way switching valve (13a) and the gas-liquid separator for ejector (22), and then the first outdoor heat exchange. After flowing into the vessel (15a) and condensing while dissipating heat to the outdoor air, it flows out of the first outdoor heat exchanger (15a).

    The high-pressure refrigerant that has flowed out of the first outdoor heat exchanger (15a) flows into the second expansion valve (14b), is depressurized to a predetermined pressure, and flows out of the second expansion valve (14b). The refrigerant that has flowed out of the second expansion valve (14b) flows into the second outdoor heat exchanger (15b), condenses again while dissipating heat to the outdoor air, and then flows out of the second outdoor heat exchanger (15b). . The refrigerant that has flowed out of the second outdoor heat exchanger (15b) flows into the ejector (21), and is further depressurized by the nozzles in the ejector (21) to become low-pressure refrigerant and flow out of the ejector (21). Since the heating on-off valve (24) is closed, the refrigerant does not flow directly from the ejector gas-liquid separator (22) to the ejector (21).

    The low-pressure refrigerant that has flowed out of the ejector (21) flows from the second port of the second four-way selector valve (13b) through the third port into the indoor heat exchanger (11), and absorbs heat from the indoor air. After evaporating, it flows out of the indoor heat exchanger (11). Here, the indoor air is cooled by the heat absorption of the refrigerant. The low-pressure refrigerant that has flowed out of the indoor heat exchanger (11) is second from the fourth port of the second four-way selector valve (13b) to the first port and from the third port of the first four-way selector valve (13a). It is sucked into the compressor (12) through the port. The low-pressure refrigerant sucked into the compressor (12) is compressed to a predetermined pressure to become a high-pressure refrigerant, and is discharged from the compressor (12). The discharged high-pressure refrigerant flows from the first port of the first four-way switching valve (13a) to the first outdoor heat exchanger (15a) through the fourth port and the ejector gas-liquid separator (22). As the refrigerant circulates in this manner, a cooling operation is performed in the air conditioner (20).

<Heating operation>
During heating operation, as shown in FIG. 3, the first four-way selector valve (13a) is in the first state (solid line in FIG. 3), and the second four-way selector valve (13b) is in the first state (solid line in FIG. 3). ) Respectively. The heating on-off valve (24) is set to open. When the compressor (12) is operated in this state, the first and second outdoor heat exchangers (15a, 15b) serve as evaporators, and the indoor heat exchanger (11) serves as a condenser to perform a heating cycle. Is called.

    The controller (4) adjusts the capacity of the compressor (12) and the valve opening of the second expansion valve (14b) as appropriate. Here, the capacity of the compressor (12) is adjusted based on the high pressure of the refrigerant circuit (10). Further, the valve opening degree of the second expansion valve (14b) is adjusted based on the degree of suction superheat.

    The high-pressure refrigerant discharged from the compressor (12) flows from the first port to the third port of the first four-way selector valve (13a) and from the first port to the third port of the second four-way selector valve (13b). (Point b2 in FIG. 3 and FIG. 4), it flows into the indoor heat exchanger (11), condenses while radiating heat to the indoor air, and then flows out of the indoor heat exchanger (11) (FIG. 3). Point b3 in FIG. Here, the indoor air is heated by the heat radiation of the refrigerant.

    The high-pressure refrigerant (driving fluid) that has flowed out of the indoor heat exchanger (11) flows into the drive channel (21a) of the ejector (21). The high-pressure refrigerant that has flowed into the drive channel (21a) is depressurized and accelerated by the nozzle (point b4 in FIGS. 3 and 4). Due to the negative pressure generated by the acceleration of the high-pressure refrigerant, the low-pressure refrigerant (suction fluid) (point b9 in FIGS. 3 and 4) flowing out from the second outdoor heat exchanger (15b) is sucked into the ejector (21).

    Then, the accelerated high-pressure refrigerant and the sucked low-pressure refrigerant merge on the upstream side of the ejection flow path (21c) of the ejector (21) (point b5 in FIGS. 3 and 4). The merged refrigerant is decelerated by the diffuser and pressurized, and then ejected from the ejection channel (21c) (point b6 in FIGS. 3 and 4).

    The refrigerant ejected from the ejector (21) flows into the gas-liquid separation container (22d) from the first port (22a) of the ejector gas-liquid separator (22) through the heating on-off valve (24) set to open. To do. And it isolate | separates into a gas refrigerant (point b6G of FIG. 3, FIG. 4) and a liquid refrigerant (point b6L of FIG. 3, FIG. 4) in a gas-liquid separation container (22d).

    The liquid refrigerant separated by the ejector gas-liquid separator (22) flows into the first outdoor heat exchanger (15a), evaporates while absorbing heat from the outdoor air, and then the first outdoor heat exchanger (15a). (Point b7 in FIGS. 3 and 4). The refrigerant that has flowed out of the first outdoor heat exchanger (15a) flows into the second expansion valve (14b), is decompressed to a predetermined pressure, and then flows out of the second expansion valve (14b) (FIG. 3). , Point b8 in FIG. The refrigerant that has flowed out of the second expansion valve (14b) flows into the second outdoor heat exchanger (15b), evaporates while absorbing heat from the outdoor air, and then flows out of the second outdoor heat exchanger (15b). (Point b9 in FIGS. 3 and 4). Then, the refrigerant that has flowed out of the second outdoor heat exchanger (15b) is sucked into the ejector (21).

    On the other hand, the gas refrigerant separated by the ejector gas-liquid separator (22) passes from the fourth port of the first four-way switching valve (13a) through the second port (point b1 in FIGS. 3 and 4), Inhaled into the compressor (12). The gas refrigerant sucked into the compressor (12) is compressed to a predetermined pressure to become a high-pressure refrigerant, and is discharged from the compressor (12). The discharged high-pressure refrigerant passes through the third port from the first port of the first four-way selector valve (13a) and the third port from the first port of the second four-way selector valve (13b) (FIG. 3, FIG. 3). 4 point b2) flows into the indoor heat exchanger (11). As the refrigerant circulates in this way, the heating operation is performed in the air conditioner (1).

    In the present embodiment, as in the first embodiment, the control of the ejector (21) (corresponding to the first expansion valve (14a) in the first embodiment) and the second expansion valve (14b) is performed by the controller (4 ).

-Effect of Embodiment 2-
According to the second embodiment, the refrigerant flowing through the upstream evaporator (15a) is also supplied to the refrigerant circuit (10) having the ejector (21) and performing the ejector cycle as in the first embodiment. It can be evaporated at a higher pressure than the evaporator (15b). Therefore, as shown in FIG. 4, in the refrigeration apparatus of Embodiment 2, the refrigerant is supplied at a temperature (T3 in FIG. 4) higher than the refrigerant inlet temperature (T4 in FIG. 4) when the evaporator is not divided. It can evaporate and can suppress the frost formation of the evaporator resulting from using a non-azeotropic refrigerant mixture.

<< Embodiment 3 >>
FIG. 5 is a refrigerant circuit diagram of an air-conditioning apparatus (40) according to Embodiment 3 of the present invention, and FIG. 6 is an air-conditioning apparatus (Embodiment 3) on a TS diagram of a non-azeotropic refrigerant mixture. It is the figure which showed the heating cycle in 40).

    The difference from the refrigerant circuit (45) of the air conditioner (1) shown in Embodiment 1 is that a high stage compressor (41a) and a low stage compressor (41b) are provided in place of the compressor (12). In place of the first expansion valve (14a), a front stage expansion valve (43a), a rear stage expansion valve (43b), and a two-stage expansion gas-liquid separator (expansion mechanism gas-liquid separator) (42) are provided. This is the point. That is, the heating cycle performed by the refrigerant circuit (45) of the air conditioner (40) constitutes a two-stage compression / two-stage expansion cycle. In FIG. 5, the same parts as those in the air conditioner (1) of the first embodiment are denoted by the same reference numerals, and only the differences will be described.

    The high stage compressor (41a) and the low stage compressor (41b) have the same configuration as the compressor (12) of Embodiment 1, and the front stage expansion valve (43a) and the rear stage expansion valve (43b) These are the structure similar to the 1st, 2nd expansion valve (14a, 14b) of Embodiment 1. FIG.

    The two-stage expansion gas-liquid separator (42) separates the refrigerant flowing out from the preceding-stage expansion valve (43a) into liquid refrigerant and gas refrigerant. Specifically, the two-stage expansion gas-liquid separator (42) includes a gas-liquid separation container (42d) for storing liquid refrigerant and gas refrigerant, and a refrigerant for flowing into the gas-liquid separation container (42d). A refrigerant inlet (42a), a liquid outlet (42c) through which liquid refrigerant after gas-liquid separation flows out, and a gas outlet (42b) through which gas refrigerant flows out are provided.

    In the refrigerant circuit (10), the second port of the second four-way selector valve (13b) and the fourth port of the first four-way selector valve (13a) are connected by a refrigerant pipe, and the refrigerant pipe In order from the second four-way selector valve (13b) to the first four-way selector valve (13a), a front stage expansion valve (43a), a bridge circuit (46), and a two-stage expansion gas-liquid separator ( 42), a rear stage expansion valve (43b), a first outdoor heat exchanger (15a), a second expansion valve (14b), and a second outdoor heat exchanger (15b).

    In addition, the refrigerant circuit (10) is a refrigerant in the two-stage expansion gas-liquid separator (42) even when the refrigerant circulation direction is switched by the first and second four-way switching valves (13a, 13b). A bridge circuit (46) is provided so as not to reverse the flow direction.

    Specifically, the bridge circuit (46) includes first to fourth check valves (CV1, CV2, CV3, CV4). The end of the refrigerant pipe extending from the front stage expansion valve (43a) to the bridge circuit (46) side is between the first check valve (CV1) and the fourth check valve (CV4) of the bridge circuit (46). It is connected. The end of the refrigerant pipe extending from the rear stage expansion valve (43b) to the bridge circuit (46) side is between the second check valve (CV2) and the third check valve (CV3) of the bridge circuit (46). It is connected to the.

    The end of the refrigerant pipe extending from the connection end of the first check valve (CV1) and the second check valve (CV2) is connected to the liquid outlet (42c) of the gas-liquid separator (42) for two-stage expansion. )It is connected to the. The end of the refrigerant pipe extending from the connection end of the third check valve (CV3) and the fourth check valve (CV4) is connected to the refrigerant inlet (42a) of the two-stage expansion gas-liquid separator (42). It is connected. Also, the end of the refrigerant pipe extending from the gas outlet (42b) of the two-stage expansion gas-liquid separator (42) is between the high-stage compressor (41a) and the low-stage compressor (41b). It is connected to the.

-Driving action-
<Cooling operation>
Next, the operation of the air conditioner (40) will be described.

    First, during cooling operation, as shown in FIG. 5, the first four-way selector valve (13a) is in the second state (broken line in FIG. 5), and the second four-way selector valve (13b) is in the second state (FIG. 5). Are respectively set to broken lines). When the high stage compressor (41a) and the low stage compressor (41b) are operated in this state, the first and second outdoor heat exchangers (15a, 15b) become condensers, and the indoor heat exchanger (11) Becomes an evaporator and a cooling cycle is performed. The controller (4) controls the capacity of the high stage compressor (41a) and the low stage compressor (41b), as well as the front stage expansion valve (43a), the rear stage expansion valve (43b), and the second stage expansion valve (14b). The valve opening is adjusted as appropriate.

    Here, the capacity of the high stage compressor (41a) is adjusted based on the high pressure of the refrigerant circuit (45), and the capacity of the low stage compressor (41b) is adjusted to the refrigerant circuit (45) of the refrigerant circuit (45). It is adjusted based on the low pressure of. The opening degree of the front stage expansion valve (43a) is adjusted based on the temperature of the liquid refrigerant flowing out from the two-stage expansion gas-liquid separator (42).

    Alternatively, the opening degree of the second expansion valve (14b) may be set to fully open, and only the opening degree of the rear stage expansion valve (43b) may be adjusted based on the suction superheat degree of the low stage compressor (41b)). Further, both the valve opening degrees of the rear stage expansion valve (43b) and the second expansion valve (14b) may be adjusted based on the degree of suction superheat. Hereinafter, a case where the opening of the second expansion valve (14b) is fully opened and only the opening of the first expansion valve (14a) is adjusted will be described.

    The high-pressure refrigerant discharged from the high-stage compressor (41a) flows from the first port of the first four-way selector valve (13a) through the fourth port into the second outdoor heat exchanger (15b), After condensing while releasing heat to the air, it flows out of the second outdoor heat exchanger (15b). The high-pressure refrigerant that has flowed out of the second outdoor heat exchanger (15b) flows through the second expansion valve (14b), flows into the first outdoor heat exchanger (15a), and is condensed while dissipating heat to the outdoor air. The first outdoor heat exchanger (15a) flows out. The high-pressure refrigerant that has flowed out of the first outdoor heat exchanger (15a) flows into the rear stage expansion valve (43b), is depressurized to a predetermined pressure, becomes an intermediate pressure refrigerant, and flows out through the rear stage expansion valve (43b).

    The intermediate-pressure refrigerant that has flowed out of the latter stage expansion valve (43b) passes through the bridge circuit (46) to the gas-liquid separation container (42d) from the refrigerant inlet (42a) of the gas-liquid separator for two-stage expansion (42). Inflow. The intermediate pressure refrigerant is separated into a gas refrigerant and a liquid refrigerant in the gas-liquid separation container (42d).

    The liquid refrigerant separated by the two-stage expansion gas-liquid separator (42) flows out from the liquid outlet (42c) of the two-stage expansion gas-liquid separator (42), passes through the bridge circuit (46), It flows into the front stage expansion valve (43a). The intermediate pressure refrigerant that has flowed into the front stage expansion valve (43a) is reduced to a predetermined pressure to become a low pressure refrigerant, and flows out from the front stage expansion valve (43a). The low-pressure refrigerant that has flowed out of the upstream expansion valve (43a) flows into the indoor heat exchanger (11) from the second port of the second four-way switching valve (13b) through the third port. The low-pressure refrigerant that has flowed into the indoor heat exchanger (11) evaporates while absorbing heat from room air, and then flows out of the indoor heat exchanger (11). Here, the indoor air is cooled by the heat absorption of the refrigerant.

    The low-pressure refrigerant that has flowed out of the indoor heat exchanger (11) is second from the fourth port of the second four-way selector valve (13b) to the first port and from the third port of the first four-way selector valve (13a). It is sucked into the low-stage compressor (41b) through the port. The low-pressure refrigerant sucked into the low-stage compressor (41b) is compressed to a predetermined pressure, becomes an intermediate-pressure refrigerant, and is discharged from the low-stage compressor (41b).

    On the other hand, the gas refrigerant separated by the two-stage expansion gas-liquid separator (42) flows out from the gas outlet (42b) of the two-stage expansion gas-liquid separator (42), and the low-stage compressor ( After joining the intermediate pressure refrigerant discharged from 41b), the refrigerant is sucked into the high stage compressor (41a), compressed to a predetermined pressure to become a high pressure refrigerant, and discharged from the high stage compressor (41a). The discharged high-pressure refrigerant flows from the first port of the first four-way switching valve (13a) through the fourth port to the second outdoor heat exchanger (15b). As the refrigerant circulates in this way, a cooling operation is performed in the air conditioner (40).

<Heating operation>
During the heating operation, as shown in FIG. 5, the first four-way selector valve (13a) is in the second state (solid line in FIG. 5), and the second four-way selector valve (13b) is in the first state (solid line in FIG. 5). ) Respectively. When the high stage compressor (41a) and the low stage compressor (41b) are operated in this state, the first and second outdoor heat exchangers (15a, 15b) become evaporators, and the indoor heat exchanger (11) Becomes a condenser and a heating cycle is performed. The controller (4) allows the capacity of the high-stage compressor (41a) and the low-stage compressor (41b), and the front-stage expansion valve (43a), the rear-stage expansion valve (43b), and the second expansion valve (14b). The valve opening is adjusted appropriately.

    Here, the capacity of the high stage compressor (41a) is adjusted based on the high pressure of the refrigerant circuit (45), and the capacity of the low stage compressor (41b) is adjusted to the refrigerant circuit (45) of the refrigerant circuit (45). It is adjusted based on the low pressure of. The opening degree of the front stage expansion valve (43a) is adjusted based on the temperature of the liquid refrigerant flowing out from the two-stage expansion gas-liquid separator (42).

    Further, both the valve opening degree of the second stage expansion valve (43b) and the second expansion valve (14b) may be adjusted based on the degree of suction superheat, or only the valve opening degree of the second expansion valve (14b) is sucked. The valve opening degree of the rear stage expansion valve (43b) may be adjusted based on the refrigerant inlet temperature of the first outdoor heat exchanger (15a) by adjusting based on the degree of superheat.

    The high-pressure refrigerant discharged from the high-stage compressor (41a) flows from the first port to the third port of the first four-way selector valve (13a) and from the first port of the second four-way selector valve (13b). After passing through 3 ports (point c4 in FIGS. 5 and 6), it flows into the indoor heat exchanger (11), condenses while dissipating heat to room air, and then flows out of the indoor heat exchanger (11) (FIG. 5). 5, point c5) in FIG. Here, the indoor air is heated by the heat radiation of the refrigerant.

    The high-pressure refrigerant that has flowed out of the indoor heat exchanger (11) flows into the pre-stage expansion valve (43a), is depressurized to a predetermined pressure, becomes an intermediate-pressure refrigerant, and flows out of the pre-stage expansion valve (43a).

    The intermediate-pressure refrigerant that has flowed out of the preceding stage expansion valve (43a) passes through the bridge circuit (46) (point c6 in FIGS. 5 and 6), and enters the refrigerant inlet (42a) of the two-stage expansion gas-liquid separator (42). ) Flows into the gas-liquid separation container (42d). The intermediate pressure refrigerant is separated into a gas refrigerant (point c6G in FIG. 6) and a liquid refrigerant (point c6L in FIG. 6) in the gas-liquid separation container (42d).

    The liquid refrigerant separated by the two-stage expansion gas-liquid separator (42) flows out from the liquid outlet (42c) of the two-stage expansion gas-liquid separator (42) (point c6L in FIGS. 5 and 6). ), And flows into the rear stage expansion valve (43b) through the bridge circuit (46). The intermediate pressure refrigerant that has flowed into the latter stage expansion valve (43b) is reduced to a predetermined pressure to become a low pressure refrigerant, and flows out of the latter stage expansion valve (43b) (point c7 in FIGS. 5 and 6). The low-pressure refrigerant that has flowed out of the rear expansion valve (43b) flows into the first outdoor heat exchanger (15a), evaporates while absorbing heat from the outdoor air, and then flows out of the first outdoor heat exchanger (15a). (Point c8 in FIGS. 5 and 6).

    The low-pressure refrigerant that has flowed out of the first outdoor heat exchanger (15a) flows into the second expansion valve (14b), is further depressurized to a predetermined pressure, and then flows out through the second expansion valve (14b) ( Point c9) in FIGS. The refrigerant that has flowed out of the second expansion valve (14b) flows into the second outdoor heat exchanger (15b), evaporates while absorbing heat from the outdoor air, and then flows out of the second outdoor heat exchanger (15b). . The low-pressure refrigerant that has flowed out of the second outdoor heat exchanger (15b) passes through the second port from the fourth port of the first four-way switching valve (13a) (point c1 in FIGS. 5 and 6), and the low-stage refrigerant. It is sucked into the compressor (41b). The low-pressure refrigerant sucked into the low-stage compressor (41b) is compressed to a predetermined pressure to become an intermediate-pressure refrigerant, and is discharged from the low-stage compressor (41b) (point c2 in FIGS. 5 and 6). .

    On the other hand, the gas refrigerant separated by the two-stage expansion gas-liquid separator (42) flows out from the gas outlet (42c) of the two-stage expansion gas-liquid separator (42), and the low-stage compressor ( 41b) is joined to the intermediate-pressure refrigerant discharged from point 41b (point c3 in FIGS. 5 and 6), and then sucked into the high-stage compressor (41a) and compressed to a predetermined pressure to become a high-pressure refrigerant. (41a). The discharged high-pressure refrigerant flows from the first port of the first four-way switching valve (13a) through the fourth port to the second outdoor heat exchanger (15b). As the refrigerant circulates in this way, heating operation is performed in the air conditioner (40).

    In the present embodiment, as in the first embodiment, the control of the rear expansion valve (43b) (corresponding to the first expansion valve (14a) in the first embodiment) and the second expansion valve (14b) is performed by the controller. Controlled by (4).

-Effect of Embodiment 3-
According to the third embodiment, the refrigerant circuit (45) having the high-stage and low-stage compressors (41a, 41b) and the front-stage and rear-stage expansion valves (43a, 43b) and performing a two-stage compression / two-stage expansion cycle. On the other hand, as in the first embodiment, the refrigerant flowing through the upstream evaporator (15a) can be evaporated at a pressure higher than that of the downstream evaporator (15b). Therefore, as shown in FIG. 6, in the refrigeration apparatus of Embodiment 3, the refrigerant is supplied at a temperature (T5 in FIG. 6) higher than the refrigerant inlet temperature (T6 in FIG. 6) when the evaporator is not divided. It can evaporate and can suppress the frost formation of the evaporator resulting from using a non-azeotropic refrigerant mixture.

<< Other Embodiments >>
About each said embodiment, it is good also as the following structures.

    For example, in each of the above embodiments, the two outdoor heat exchangers (15a, 15b) (evaporator) are provided and the second expansion valve (14b) is provided between them, but one outdoor heat exchanger (15 ) An extension U-shaped tube (14d) may be connected to a heat transfer tube (U-shaped tube) in the middle of the evaporator, and a second expansion valve (14b) may be provided on the extended U-shaped tube (14d). However, instead of the second expansion valve (14b), a capillary tube (14c) may be provided on the extended U-shaped tube (14d) (see FIG. 11). That is, the present invention only needs to be configured to depressurize the refrigerant in the middle of evaporation.

    Moreover, although each said embodiment demonstrated the air conditioning apparatus (1) which can switch a cooling / heating cycle, it can apply similarly also to another refrigeration apparatus.

    For example, the present invention can be applied to a dedicated heating cycle machine such as a water heater or a floor heater. In this case, in the refrigerant circuit (10), the two four-way switching valves (13a, 13b) in FIG. 1 are omitted, and the compressor (12), the indoor heat exchanger (11), and the first expansion valve (14a) are omitted. The first outdoor heat exchanger (15a), the second expansion valve (14b), and the second outdoor heat exchanger (15b) are sequentially connected. The indoor heat exchanger (11) is configured as a use-side condenser, and the first outdoor heat exchanger (15a) and the second outdoor heat exchanger (15b) are configured as a heat source-side evaporator.

    Further, the present invention can also be applied to a dedicated cooling cycle machine such as a refrigerator, a freezing container, a turbo refrigerator, or a chiller. In this case, in the refrigerant circuit (10), the two four-way switching valves (13a, 13b) in FIG. 1 are omitted, and the compressor (12), the indoor heat exchanger (11), and the first expansion valve (14a) are omitted. The first outdoor heat exchanger (15a), the second expansion valve (14b), and the second outdoor heat exchanger (15b) are sequentially connected. The indoor heat exchanger (11) is configured as a heat source side condenser, and the first outdoor heat exchanger (15a) and the second outdoor heat exchanger (15b) are configured as utilization side evaporators.

    In this embodiment, although the 1st outdoor heat exchanger (15a) and the 2nd outdoor heat exchanger (15b) are made into a different body, it is not limited to this, A 1st outdoor heat exchanger (15a) and 2nd The outdoor heat exchanger (15b) and the second expansion valve (14b) may be integrated.

    In this embodiment, a mixed refrigerant of HFC-32 and HFO-1234yf is used as the non-azeotropic mixed refrigerant. However, the present invention is not limited to this. For example, a mixed refrigerant of HFC-32 and HFO-1234 is used. , A mixed refrigerant of HFC-32 and other refrigerants represented by tetrafluoropentene (for example, HFO-1234ze), a mixed refrigerant of HFC-32 and HFO-1225 or R407c, and other non-azeotropic mixed refrigerants There may be.

    Further, for example, in the above-described embodiment, a refrigerant (1,2,3,3,3-pentafluoro-1-propene, 2,3,3 represented by the above molecular formula and having one double bond in the molecular structure thereof is used. , 3-tetrafluoro-1-propene, 1,3,3,3-tetrafluoro-1-propene, 1,2,3,3-tetrafluoro-1-propene, 3,3,3-trifluoro-1 -Propene, 1,2,2-trifluoro-1-propene, 2-fluoro-1-propene), HFC-32 (difluoromethane), HFC-125 (pentafluoroethane), HFC-134 (1,1 , 2,2-tetrafluoroethane), HFC-134a (1,1,1,2-tetrafluoroethane), HFC-143a (1,1,1-trifluoroethane), HFC-152a (1,1- Gif Oroethane), HFC-161 (fluoroethane), HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane), HFC-236ea (1,1,1,2,3,3- Hexafluoropropane), HFC-236fa (1,1,1,3,3,3-hexafluoroethane), HFC-365mfc (1,1,1,3,3-pentafluorobutane), methane, ethane, propane , Propene, butane, isobutane, pentane, 2-methylbutane, cyclopentane, dimethyl ether, bis-trifluoromethyl-sulfide, carbon dioxide, and helium may be used as a mixed refrigerant.

    For example, a mixed refrigerant composed of two components of HFO-1234yf and HFC-32 may be used. In this case, a mixed refrigerant composed of 78.2% by mass of HFO-1234yf and 21.8% by mass of HFC-32 can be used. The mixed refrigerant of HFO-1234yf and HFC-32 may have a ratio of HFO-1234yf of 70% by mass to 94% by mass and a ratio of HFC-32 of 6% by mass to 30% by mass, preferably The ratio of HFO-1234yf may be 77% by mass or more and 87% by mass or less and the ratio of HFC-32 may be 13% by mass or more and 23% by mass or less, and more preferably the ratio of HFO-1234yf is 77% by mass or more and 79% by mass. It is more preferable if the ratio of HFC-32 is 21% by mass or more and 23% by mass or less in mass% or less.

    Further, a mixed refrigerant of HFO-1234yf and HFC-125 may be used. In this case, the ratio of HFC-125 is preferably 10% by mass or more, and more preferably 10% by mass or more and 20% by mass or less.

    Moreover, you may use the mixed refrigerant | coolant which consists of 3 components of HFO-1234yf, HFC-32, and HFC-125. In this case, a mixed refrigerant composed of 52% by mass of HFO-1234yf, 23% by mass of HFC-32, and 25% by mass of HFC-125 can be used.

    In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

    As described above, the present invention is useful for a refrigeration apparatus including a refrigerant circuit that performs a refrigeration cycle using a non-azeotropic refrigerant mixture.

It is a refrigerant circuit figure of the air harmony device concerning Embodiment 1 of the present invention. It is a TS diagram of the refrigerating cycle which the refrigerant circuit of the air harmony device concerning Embodiment 1 performs. It is a TS diagram for demonstrating control of an expansion valve. It is a TS diagram for demonstrating control of an expansion valve. It is a graph which shows the relationship between the division | segmentation number of an evaporator, and its evaporation capability. It is a refrigerant circuit figure of the air conditioning apparatus which concerns on Embodiment 2 of this invention. It is a TS diagram of the refrigerating cycle which the refrigerant circuit of the air harmony device concerning Embodiment 2 performs. It is a refrigerant circuit figure of the air conditioning apparatus which concerns on Embodiment 3 of this invention. It is a TS diagram of the refrigerating cycle which the refrigerant circuit of the air harmony device concerning Embodiment 3 performs. It is a figure which shows a part of refrigerant circuit which concerns on other embodiment. It is a figure which shows a part of refrigerant circuit which concerns on other embodiment. It is a refrigerant circuit figure of the conventional air conditioning apparatus. It is a TS diagram of the refrigerating cycle which the refrigerant circuit of the conventional air harmony device performs.

Explanation of symbols

1 Air conditioner (refrigeration equipment)
4 Controller (control means)
10 Refrigerant circuit
11 Indoor heat exchanger
12 Compressor (compression mechanism)
14a First expansion valve (expansion mechanism)
14b Second expansion valve (pressure reduction mechanism)
15 Outdoor heat exchanger
15a First outdoor heat exchanger (front evaporator)
15b Second outdoor heat exchanger (second-stage evaporator)

Claims (20)

A refrigerant circuit (10) to which a compression mechanism (12), a condenser (11), an expansion mechanism (14a), and an evaporator (15) are connected;
A refrigeration apparatus that performs a refrigeration cycle by reversibly circulating a non-azeotropic refrigerant mixture through the refrigerant circuit (10),
The refrigerant circuit (10) is configured to supply the refrigerant in the middle of evaporation of the evaporator (15) one or more times during a refrigeration cycle in which the condenser (11) is on the use side and the evaporator (15) is on the heat source side. A refrigeration apparatus comprising a decompression mechanism (14b) for decompressing in stages. A refrigerant circuit (10) in which a compression mechanism (12), a use side condenser (11), an expansion mechanism (14a), and a heat source side evaporator (15) are connected in order,
A refrigeration apparatus that performs a refrigeration cycle by circulating a non-azeotropic refrigerant mixture through the refrigerant circuit (10),
The refrigerant circuit (10) includes a decompression mechanism (14b) for decompressing the refrigerant in the course of evaporation of the evaporator (15) one or more times stepwise. A refrigerant circuit (10) in which a compression mechanism (12), a heat source side condenser (11), an expansion mechanism (14a), and a use side evaporator (15) are sequentially connected;
A refrigeration apparatus that performs a refrigeration cycle by circulating a non-azeotropic refrigerant mixture through the refrigerant circuit (10),
The refrigerant circuit (10) includes a decompression mechanism (14b) for decompressing the refrigerant in the course of evaporation of the evaporator (15) one or more times stepwise. In claim 1,
The temperature of the refrigerant when the evaporator (15) on the heat source side is frosted is set as a lower limit temperature, and the expansion mechanism (in order to prevent the inlet refrigerant temperature of the evaporator (15) from falling below the lower limit temperature). A refrigeration apparatus comprising control means (4) for controlling 14a). In claim 1,
A refrigeration apparatus comprising control means (4) for controlling the decompression mechanism (14b) so that the outlet refrigerant temperature of the heat source side evaporator (15) becomes a predetermined target value. In claim 1,
The temperature of the refrigerant when the evaporator (15) on the heat source side is frosted is set as the lower limit temperature, and a predetermined target value of the outlet refrigerant temperature of the evaporator (15) on the heat source side is set as the upper limit temperature. Control means (4) for controlling the pressure reducing mechanism (14b) is set so that the refrigerant temperature during the evaporation of the evaporator (15) does not exceed the upper limit temperature and does not fall below the lower limit temperature. A refrigeration apparatus characterized by comprising: In claim 2 or 3,
The temperature of the refrigerant when the evaporator (15) frosts is set as the lower limit temperature, and the expansion mechanism (14a) is set so that the inlet refrigerant temperature of the evaporator (15) does not fall below the lower limit temperature. A refrigeration apparatus comprising control means (4) for controlling. In claim 2 or 3,
A refrigeration apparatus comprising control means (4) for controlling the decompression mechanism (14b) so that the outlet refrigerant temperature of the evaporator (15) becomes a predetermined target value. In claim 2 or 3,
The temperature of the refrigerant when the evaporator (15) is frosted is set as the lower limit temperature, and a predetermined target value of the outlet refrigerant temperature of the evaporator (15) is set as the upper limit temperature, and the evaporator (15) comprising a control means (4) for controlling the pressure reducing mechanism (14b) so that the refrigerant temperature in the course of evaporation does not exceed the upper limit temperature and does not fall below the lower limit temperature. Refrigeration equipment. In any one of Claim 1, 4 thru | or 6,
The evaporator (15) on the heat source side is connected to a pre-stage evaporator (15a) in which the refrigerant expanded by the expansion mechanism (14a) evaporates, and to the pre-stage evaporator (15a) via a connection pipe (16). The rear evaporator (15b) in which the refrigerant evaporated in the former evaporator (15a) further evaporates,
The refrigeration apparatus, wherein the decompression mechanism (14b) is provided in the connection pipe (16). In any one of Claims 2, 3, 7 to 9,
The evaporator (15) is connected to the pre-stage evaporator (15a) in which the refrigerant expanded by the expansion mechanism (14a) evaporates, and connected to the pre-stage evaporator (15a) via a connection pipe (16). And the latter stage evaporator (15b) in which the refrigerant evaporated in the evaporator (15a) further evaporates,
The refrigeration apparatus, wherein the decompression mechanism (14b) is provided in the connection pipe (16). In claim 10 or 11,
The expansion mechanism includes a drive channel (21a) through which the refrigerant condensed in the condenser (11) flows, and a refrigerant evaporated in the post-stage evaporator (15b) by the high-pressure refrigerant flowing through the drive channel (21a). Ejector (21c) having a suction flow path (21b) that flows through the suction flow path (21b), and a jet flow path (21c) that jets the refrigerant flowing through the suction flow path (21b) and the refrigerant flowing through the drive flow path (21a) )
The refrigerant circuit (10) separates the refrigerant ejected from the ejection flow path (21c) of the ejector (21) into liquid refrigerant and gas refrigerant, and the separated liquid refrigerant is the liquid in the upstream evaporator (15a). A refrigeration apparatus comprising: an ejector gas-liquid separator (22) configured to flow to the side end and to allow the separated gas refrigerant to flow to the suction side of the compression mechanism (12). In claim 10 or 11,
The compression mechanism includes a low-stage compressor (41b) that compresses the refrigerant evaporated in the post-stage evaporator (15b), and a high-stage compressor (41a) that further compresses the refrigerant compressed in the low-stage compressor (41b). ) And
The expansion mechanism includes a front stage expansion mechanism (43a) that expands the refrigerant condensed in the condenser (11) and a rear stage expansion mechanism (43b) that further expands the refrigerant expanded by the front stage expansion mechanism (43a). And
The refrigerant circuit (45) separates the refrigerant expanded by the front stage expansion mechanism (43a) into a liquid refrigerant and a gas refrigerant, and the separated liquid refrigerant flows to the rear stage expansion mechanism (43b), and after the separation, A refrigerating apparatus comprising an expansion mechanism gas-liquid separator (42) configured to allow a gas refrigerant to flow to a discharge pipe of the low-stage compressor (41b). In any one of Claims 1 thru | or 13,
The non-azeotropic refrigerant mixture is represented by molecular formula 1: C ₃ H _m F _n (where m and n are integers of 1 to 5, and the relationship of m + n = 6 is established) and in the molecular structure. A refrigeration apparatus comprising a mixed refrigerant including a refrigerant having one double bond. In claim 14,
The molecular formula 1 is represented by C ₃ H _m F _n (where m and n are integers of 1 or more and 5 or less, and the relationship of m + n = 6 is established) and has one double bond in the molecular structure. The refrigerant is 2,3,3,3-tetrafluoro-1-propene. In claim 14 or 15,
The non-azeotropic refrigerant mixture is represented by the molecular formula 1: C ₃ H _m F _n (where m and n are integers of 1 or more and 5 or less, and the relationship of m + n = 6 is established) and in the molecular structure. A refrigeration apparatus comprising a refrigerant mixture including a refrigerant having one double bond and difluoromethane. In any one of claims 14 to 16,
The non-azeotropic refrigerant mixture is represented by the molecular formula 1: C ₃ H _m F _n (where m and n are integers of 1 or more and 5 or less, and the relationship of m + n = 6 is established) and in the molecular structure. A refrigeration apparatus comprising a refrigerant mixture including a refrigerant having one double bond and pentafluoroethane. In claim 14,
The non-azeotropic refrigerant mixture is a refrigerant mixture of HFC-32 and HFO-1225. In claim 14,
The non-azeotropic refrigerant mixture is a refrigerant mixture of HFC-32 and HFO-1234. In claim 19,
The refrigeration apparatus, wherein the HFO-1234 is the HFO-1234yf.

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