JP7216308B2 - refrigeration cycle equipment - Google Patents

Description

It relates to a refrigeration cycle device.

Refrigerants used in refrigeration cycle devices are required to satisfy various requirements such as high safety and low environmental impact in addition to performance as a refrigerant. For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2008-281326) describes the use of R1234yf, which has a low global warming potential, in a refrigeration cycle device instead of R134a.

However, among various requirements for refrigerants, it is generally difficult to select a refrigerant that is efficient and capable of obtaining sufficient performance regardless of operating conditions.

A refrigeration cycle device according to a first aspect includes a refrigeration cycle, a changing section, and a control section. The refrigeration cycle uses a non-azeotropic refrigerant mixture containing a first refrigerant and a second refrigerant. The changing unit changes the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the refrigeration cycle. The control unit controls the operation of the change unit. The controller executes a first mode and a second mode. The first mode is a mode in which the operation of the change unit is controlled to allow the second refrigerant to flow substantially independently through the refrigeration cycle. The second mode is a mode in which the operation of the change unit is controlled to allow the mixed refrigerant of the first refrigerant and the second refrigerant to flow through the refrigeration cycle.

The refrigeration cycle device of the first aspect can use the second refrigerant substantially alone, or can use a non-azeotropic mixed refrigerant containing the first refrigerant and the second refrigerant. Therefore, a refrigerant of suitable composition can be used.

A refrigerating cycle device according to a second aspect is the refrigerating cycle device according to the first aspect, in which in the first mode, a refrigerant having a second refrigerant concentration of 92 wt % or more flows through the refrigerating cycle.

A refrigerating cycle device according to a third aspect is the refrigerating cycle device according to the second aspect, in which in the first mode, a refrigerant having a second refrigerant concentration of 98 wt % or more flows through the refrigerating cycle.

A refrigeration cycle device according to a fourth aspect is the refrigeration cycle device according to any one of the first aspect to the third aspect, and further includes a detector. The detection unit detects the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the refrigeration cycle. The control unit controls the operation of the changing unit so that the composition ratio of the first refrigerant and the second refrigerant detected by the detection unit becomes the target composition ratio.

In the refrigeration cycle device of the fourth aspect, the composition ratio between the first refrigerant and the second refrigerant is changed while detecting the composition ratio of the refrigerant, so refrigerant with an appropriate composition can be used according to the operating conditions.

A refrigeration cycle device according to a fifth aspect is the refrigeration cycle device according to any one of the first to fourth aspects, wherein the boiling point of the second refrigerant is higher than the boiling point of the first refrigerant.

A refrigerating cycle device according to a sixth aspect is the refrigerating cycle device according to the fifth aspect, wherein the refrigerating cycle includes a utilization heat exchanger that adjusts the temperature of a target for temperature adjustment. When using the utilization heat exchanger as an evaporator, the control unit executes the first mode. When using the utilization heat exchanger as a radiator, the control unit executes the second mode.

In the refrigerating cycle apparatus of the sixth aspect, when the heat exchanger is used as an evaporator, the second refrigerant can be used substantially alone to allow efficiency-oriented operation. On the other hand, when the heat exchanger is used as a heat radiator, the required capacity can be obtained by using the non-azeotropic mixed refrigerant of the first refrigerant and the second refrigerant.

A refrigerating cycle apparatus according to a seventh aspect is the refrigerating cycle apparatus according to the sixth aspect, wherein when the utilization heat exchanger is used as a heat radiator, the controller controls the first mode or the second mode.

In the refrigeration cycle apparatus of the seventh aspect, even when the heat exchanger is used as a heat radiator, the second refrigerant may be used if it is unnecessary to use the mixed refrigerant of the first refrigerant and the second refrigerant due to the capacity. It can be used almost independently to drive with an emphasis on efficiency.

A refrigerating cycle device according to an eighth aspect is the refrigerating cycle device according to the seventh aspect, wherein the refrigerating cycle includes a compressor. The controller further controls the rotation speed of the compressor. The control unit executes the second mode when the required capacity cannot be obtained even if the rotational speed of the compressor is increased to a predetermined rotational speed while the first mode is being executed.

In the refrigeration cycle device of the eighth aspect, it is possible to obtain the necessary capacity while suppressing the decrease in efficiency.

A refrigerating cycle apparatus according to a ninth aspect is the refrigerating cycle apparatus according to the sixth aspect or the seventh aspect, wherein the control unit controls the operation of the changing unit when executing the second mode to operate the refrigerating cycle. The composition ratio of the first refrigerant and the second refrigerant in the flowing refrigerant is changed between the first composition ratio and the second composition ratio. The second composition ratio has a higher proportion of the first refrigerant than the first composition ratio.

In the refrigeration cycle device of the ninth aspect, the composition ratio between the first refrigerant and the second refrigerant is changed stepwise, so that the necessary capacity can be obtained while suppressing the decrease in efficiency.

A refrigerating cycle device according to a tenth aspect is the refrigerating cycle device according to the ninth aspect, wherein the refrigerating cycle includes a compressor. The controller further controls the rotation speed of the compressor. The control unit changes either the number of rotations of the compressor or the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the refrigeration cycle according to changes in the required capacity of the refrigeration cycle device.

In the refrigeration cycle device of the tenth aspect, it is possible to obtain the necessary capacity while suppressing the decrease in efficiency.

A refrigerating cycle device according to an eleventh aspect is the refrigerating cycle device according to the tenth aspect, wherein, when the required capacity increases, the control unit controls the rotation speed of the compressor and the first Of the composition ratios of the refrigerant and the second refrigerant, the one with the smaller amount of increase in the electric power of the compressor when changed is changed.

In the refrigeration cycle device of the eleventh aspect, it is possible to obtain the necessary capacity while suppressing the decrease in efficiency.

A refrigerating cycle device according to a twelfth aspect is the refrigerating cycle device according to the tenth or eleventh aspect, wherein the controller controls, when the required capacity is reduced, the ratio of the first refrigerant in the refrigerant flowing through the refrigerating cycle to When the ratio is higher than the predetermined value, the changing unit is controlled to decrease the ratio of the first refrigerant in the refrigerant flowing through the refrigerating cycle, and when the ratio of the first refrigerant in the refrigerant flowing through the refrigerating cycle is equal to or less than the predetermined value, Decrease compressor speed.

In the refrigeration cycle apparatus of the twelfth aspect, it is possible to obtain the necessary capacity while suppressing the decrease in efficiency.

A refrigeration cycle device according to a thirteenth aspect is the refrigeration cycle device according to any one of the first to twelfth aspects, wherein the first refrigerant is CO2. The second refrigerant is R1234Ze or R1234yf.

A refrigeration cycle device according to a fourteenth aspect is the refrigeration cycle device according to any one of the first aspect to the twelfth aspect, wherein the first refrigerant is R1132(E) or R1123. The second refrigerant is R1234Ze or R1234yf.

1 is a schematic configuration diagram of a refrigeration cycle apparatus according to one embodiment; FIG. Schematically represents changes in COP when changing the capacity by changing the rotation speed of the compressor motor and changes in COP when changing the capacity by changing the ratio of the first refrigerant in the refrigerant. It is a diagram of It is an example of the flowchart of the control performed at the time of the capacity|capacitance shortage of a refrigerating-cycle apparatus. It is an example of the flowchart of the control performed when the capacity|capacitance of a refrigerating-cycle apparatus is excessive. 2 is a schematic configuration diagram of a refrigeration cycle apparatus according to Modification A; FIG. FIG. 11 is a schematic configuration diagram of a refrigeration cycle apparatus according to Modification G;

Embodiments of the refrigeration cycle apparatus of the present disclosure will be described below with reference to the drawings.

A refrigeration cycle device is a device that uses a vapor compression refrigeration cycle to perform at least one of cooling of a temperature-adjusted object and heating of a temperature-adjusted object. The refrigeration cycle device of the present disclosure uses a non-azeotropic mixed refrigerant as a refrigerant. The refrigeration cycle device of the present disclosure changes the composition ratio of the refrigerant flowing through the refrigeration cycle according to conditions, as described later.

<First embodiment>
(1) Overall Overview A refrigeration cycle apparatus 100 according to the first embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a refrigeration cycle apparatus 100. As shown in FIG.

Here, the refrigeration cycle device 100 is an air conditioner that cools and heats the air to be temperature-controlled. However, the refrigeration cycle device 100 is not limited to this, and may be a device that cools and heats a liquid (for example, water) whose temperature is to be adjusted.

The refrigerating cycle device 100 mainly includes a main refrigerant circuit 50 as an example of a refrigerating cycle, a changing section 70, a detecting section 150, and a controller 110, as shown in FIG. The refrigerant circuit 200 includes the main refrigerant circuit 50 and a first bypass flow path 80 of a change section 70 (to be described later) connected to the main refrigerant circuit 50 .

The refrigerant circuit 200 is filled with a non-azeotropic refrigerant mixture. In other words, the main refrigerant circuit 50 uses a non-azeotropic refrigerant mixture. A non-azeotropic refrigerant mixture is a mixture of at least two refrigerants. The refrigerant circuit 200 of the refrigeration cycle apparatus 100 of the first embodiment is filled with a non-azeotropic mixed refrigerant containing only two types of refrigerants (first refrigerant and second refrigerant). However, it is not limited to this, and the non-azeotropic refrigerant mixture may be a mixture of three or more refrigerants. For example, the second refrigerant may be an azeotropic or pseudo-azeotropic refrigerant mixture containing two or more refrigerants instead of one refrigerant. In short, the non-azeotropic mixed refrigerant is a mixed refrigerant of an azeotropic or pseudo-azeotropic mixed refrigerant containing two or more refrigerants as a second refrigerant and a first refrigerant that is non-azeotropic with the second refrigerant. Even though.

Specifically, but not limited to, the first refrigerant is CO2 (carbon dioxide) and the second refrigerant is HFO (hydrofluoroolefin). HFO is a refrigerant with a very low global warming potential. A specific non-limiting example of HFO for use as the second refrigerant is R1234Ze (cis-1,3,3,3-tetrafluoropropene). Further, for example, instead of R1234Ze, R1234yf (2,3,3,3-tetrafluoropropene) may be used as HFO of the second refrigerant. CO2 is a refrigerant with a relatively low boiling point, and R1234Ze and R1234yf are refrigerants with a relatively high boiling point. In other words, the boiling point of the second refrigerant is higher than the boiling point of the first refrigerant. Hereinafter, the first refrigerant may be called a low boiling point refrigerant, and the second refrigerant may be called a high boiling point refrigerant.

The ratio of the total weight of the first refrigerant charged in the refrigerant circuit 200 to the total weight of all refrigerants charged in the refrigerant circuit 200 of the refrigeration cycle device 100 is preferably 20 wt% or less.

The main refrigerant circuit 50, the changing section 70, the detecting section 150 and the controller 110 will be outlined.

The main refrigerant circuit 50 mainly includes a compressor 10, a flow path switching mechanism 15, a heat source heat exchanger 20, an expansion mechanism 30, and a utilization heat exchanger 40, as shown in FIG. The compressor 10, the flow path switching mechanism 15, the heat source heat exchanger 20, the expansion mechanism 30, and the utilization heat exchanger 40 are connected by refrigerant pipes 52a to 52e, which will be described later, to form a main refrigerant circuit 50. (See Figure 1). The refrigeration cycle device 100 circulates the refrigerant in the main refrigerant circuit 50 to cool and heat the air whose temperature is to be adjusted.

The changing unit 70 is a mechanism that changes the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 .

The detector 150 detects the composition ratio of the refrigerant circulating in the main refrigerant circuit 50 .

1, the refrigeration cycle apparatus 100 has a heat source unit 2 having a casing (not shown) and a utilization unit connected to the heat source unit 2 via a refrigerant pipe. 4 and . The heat source unit 2 is installed, for example, on the roof of the building in which the refrigerating cycle device 100 is installed, in a machine room, or around the building in which the refrigerating cycle device 100 is installed. The usage unit 4 is arranged in a space to be air-conditioned or in a space near the space to be air-conditioned (for example, in the ceiling or in a machine room). Although not limited, the casing of the heat source unit 2 includes the compressor 10 of the main refrigerant circuit 50, the flow path switching mechanism 15, the heat source heat exchanger 20, the expansion mechanism 30, the changing section 70, and the detecting section 150. , are mainly accommodated. The casing of the utilization unit 4 mainly accommodates the utilization heat exchanger 40 of the main refrigerant circuit 50 .

The controller 110 controls operations of various components of the refrigeration cycle apparatus 100 .

For example, the controller 110 controls operations of the changing unit 70 . The controller 110 executes the first mode and the second mode by controlling the operation of the changing section 70 . The first mode is a mode in which the operation of the changing unit 70 is controlled to allow the second refrigerant to flow through the main refrigerant circuit 50 substantially independently. The second mode is a mode in which the operation of the changing unit 70 is controlled to allow the mixed refrigerant of the first refrigerant and the second refrigerant to flow through the main refrigerant circuit 50 .

It should be noted that the flow of the second refrigerant substantially alone is not limited to the state of flowing the second refrigerant that does not contain the first refrigerant, but the state of flowing the second refrigerant having a high concentration equal to or higher than a predetermined concentration (substantially state in which the second refrigerant flows alone). Specifically, the state in which the second refrigerant flows substantially alone through the main refrigerant circuit 50 includes the state in which the second refrigerant having a concentration of 92 wt % or more flows through the main refrigerant circuit 50 . In addition, in the first mode, it is preferable that the refrigerant with the highest second refrigerant concentration (the refrigerant with the lowest first refrigerant concentration) is allowed to flow through the main refrigerant circuit 50 . Preferably, in the first mode, the main refrigerant circuit 50 is supplied with a refrigerant having a second refrigerant concentration of 98 wt % or higher.

(2) Detailed Configuration (2-1) Main Refrigerant Circuit The main refrigerant circuit 50 includes, as shown in FIG. and a utilization heat exchanger 40 .

The main refrigerant circuit 50 includes a suction pipe 52a as shown in FIG. , a discharge pipe 52b, a first gas refrigerant pipe 52c, a liquid refrigerant pipe 52d, and a second gas refrigerant pipe 52e (see FIG. 1). The suction pipe 52 a connects the suction port 10 b of the compressor 10 and the channel switching mechanism 15 . The discharge pipe 52b connects the discharge port 10c of the compressor 10 and the channel switching mechanism 15 . The first gas refrigerant pipe 52 c connects the flow path switching mechanism 15 and the gas end of the heat source heat exchanger 20 . The liquid refrigerant pipe 52 d connects the liquid end of the heat source heat exchanger 20 and the liquid end of the heat utilization heat exchanger 40 . An expansion mechanism 30 is provided in the liquid refrigerant pipe 52d. The second gas refrigerant pipe 52 e connects the gas end of the heat utilization heat exchanger 40 and the channel switching mechanism 15 .

(2-1-1) Compressor The compressor 10 sucks low-pressure refrigerant in the refrigeration cycle from the suction port 10b, compresses the refrigerant in a compression mechanism (not shown), and releases high-pressure refrigerant in the refrigeration cycle from the discharge port 10c. Dispense. Although only one compressor 10 is depicted in FIG. 1, the main refrigerant circuit 50 may have multiple compressors 10 connected in series or in parallel.

Compressor 10 is, for example, a scroll compressor. However, the compressor 10 is not limited to this, and may be a compressor of a type other than a scroll compressor, such as a rotary compressor. The type of compressor 10 may be selected as appropriate.

The compressor 10 is, but not limited to, an inverter-controlled compressor in which the rotation speed of the motor 10a is variable. A later-described controller 110 that controls the operation of the compressor 10 controls the rotation speed of the motor 10a of the compressor 10 according to, for example, the air conditioning load.

(2-1-2) Channel Switching Mechanism The channel switching mechanism 15 is a mechanism that switches the flow direction of the refrigerant in the main refrigerant circuit 50 according to the operation mode (cooling operation mode/heating operation mode) of the refrigeration cycle device 100. be. The cooling operation mode is an operation mode of the refrigeration cycle apparatus 100 that causes the heat source heat exchanger 20 to function as a radiator and the utilization heat exchanger 40 to function as an evaporator. The heating operation mode is an operation mode of the refrigeration cycle apparatus 100 in which the utilization heat exchanger 40 functions as a radiator and the heat source heat exchanger 20 functions as an evaporator.

In the cooling operation mode, the flow path switching mechanism 15 switches the flow direction of the refrigerant in the main refrigerant circuit 50 so that the refrigerant discharged from the compressor 10 is sent to the heat source heat exchanger 20 . Specifically, in the cooling operation mode, the channel switching mechanism 15 communicates the suction pipe 52a with the second gas refrigerant pipe 52e and communicates the discharge pipe 52b with the first gas refrigerant pipe 52c (solid line in FIG. 1). reference).

In the heating operation mode, the flow path switching mechanism 15 switches the flow direction of the refrigerant in the main refrigerant circuit 50 so that the refrigerant discharged from the compressor 10 is sent to the heat utilization heat exchanger 40 . Specifically, in the heating operation mode, the channel switching mechanism 15 communicates the suction pipe 52a with the first gas refrigerant pipe 52c, and communicates the discharge pipe 52b with the second gas refrigerant pipe 52e (broken line in FIG. 1). reference).

The channel switching mechanism 15 is, for example, a four-way switching valve. However, the channel switching mechanism 15 may be realized by means other than the four-way switching valve. For example, the channel switching mechanism 15 may be configured by combining a plurality of solenoid valves and pipes so as to switch the flow direction of the refrigerant.

(2-1-3) Heat Source Heat Exchanger The heat source heat exchanger 20 functions as a refrigerant radiator when the refrigeration cycle device 100 is operated in the cooling operation mode, and functions as a refrigerant radiator when the refrigeration cycle device 100 is in the heating operation mode. When operated, it functions as an evaporator of refrigerant. Although only one heat source heat exchanger 20 is illustrated in FIG. 1, the main refrigerant circuit 50 may have a plurality of heat source heat exchangers 20 arranged in parallel.

Although not limited, the heat source heat exchanger 20 is, for example, a fin-and-tube heat exchanger having a plurality of heat transfer tubes and a plurality of heat transfer fins.

One end of the heat source heat exchanger 20 is connected to the first gas refrigerant pipe 52c as shown in FIG. A liquid refrigerant pipe 52d is connected to the other end of the heat source heat exchanger 20 as shown in FIG.

When the refrigeration cycle device 100 is operated in the cooling operation mode, refrigerant flows into the heat source heat exchanger 20 from the first gas refrigerant pipe 52c. The refrigerant that has flowed into the heat source heat exchanger 20 from the first gas refrigerant pipe 52c exchanges heat with air supplied by a fan (not shown) to radiate heat, and at least a portion of the refrigerant is condensed. The refrigerant that has dissipated heat in the heat source heat exchanger 20 flows out to the liquid refrigerant pipe 52d.

When the refrigeration cycle device 100 is operated in the heating operation mode, refrigerant flows into the heat source heat exchanger 20 from the liquid refrigerant pipe 52d. The refrigerant that has flowed into the heat source heat exchanger 20 from the liquid refrigerant pipe 52d absorbs heat and evaporates by exchanging heat with air supplied by a fan (not shown) in the heat source heat exchanger 20 . The refrigerant that has absorbed heat (heated) in the heat source heat exchanger 20 flows out to the first gas refrigerant pipe 52c.

In this embodiment, in the heat source heat exchanger 20, heat is exchanged between the refrigerant flowing inside and the air as the heat source supplied to the heat source heat exchanger 20. It is not limited to a heat exchanger that exchanges heat between and a refrigerant. For example, the heat source heat exchanger 20 may be a heat exchanger that exchanges heat between a refrigerant flowing inside and a liquid as a heat source supplied to the heat source heat exchanger 20 .

(2-1-4) Expansion Mechanism The expansion mechanism 30 is a mechanism for decompressing the refrigerant and adjusting the flow rate of the refrigerant. In this embodiment, the expansion mechanism 30 is an electronic expansion valve whose opening is adjustable. The degree of opening of the expansion mechanism 30 is appropriately adjusted according to the operating conditions. Note that the expansion mechanism 30 is not limited to an electronic expansion valve, and may be a thermostatic expansion valve or a capillary tube.

(2-1-5) Utilization heat exchanger The utilization heat exchanger 40 functions as a refrigerant evaporator when the refrigeration cycle device 100 is operated in the cooling operation mode, and functions as a refrigerant evaporator when the refrigeration cycle device 100 is operated in the heating operation mode. It functions as a heat radiator for the refrigerant when it is operated. When functioning as an evaporator, the utilization heat exchanger 40 cools the object of temperature adjustment (air in this embodiment). The utilization heat exchanger 40 heats a temperature-adjusted object (air in this embodiment) when functioning as a radiator.

In addition, in the example shown in FIG. 1 , the refrigeration cycle apparatus 100 has only one utilization heat exchanger 40 . However, it is not limited to this. The main refrigerant circuit 50 of the refrigeration cycle device 100 may have a plurality of utilization heat exchangers 40 arranged in parallel. Further, each utilization unit 4 may have an expansion mechanism (not shown) (for example, an electronic expansion valve with adjustable opening) arranged on the liquid side of the utilization heat exchanger 40 .

Although not limited, the utilization heat exchanger 40 is, for example, a fin-and-tube heat exchanger having a plurality of heat transfer tubes and a plurality of heat transfer fins.

One end of the utilization heat exchanger 40 is connected to a liquid refrigerant pipe 52d as shown in FIG. A second gas refrigerant pipe 52e is connected to the other end of the utilization heat exchanger 40 as shown in FIG.

When the refrigerating cycle device 100 is operated in the cooling operation mode, refrigerant flows into the utilization heat exchanger 40 from the liquid refrigerant pipe 52d. The refrigerant flowing into the utilization heat exchanger 40 from the liquid refrigerant pipe 52d exchanges heat with air supplied by a fan (not shown) in the utilization heat exchanger 40, absorbs heat, and evaporates. The refrigerant that has absorbed heat (heated) in the heat utilization heat exchanger 40 flows out to the second gas refrigerant pipe 52e. The air cooled by the heat exchanger 40 and the temperature of which is to be adjusted is blown out into the air-conditioned space.

When the refrigeration cycle device 100 is operated in the heating operation mode, refrigerant flows into the utilization heat exchanger 40 from the second gas refrigerant pipe 52e. The refrigerant flowing into the utilization heat exchanger 40 from the second gas refrigerant pipe 52e radiates heat by exchanging heat with air supplied by a fan (not shown), and is at least partially condensed. The refrigerant that has dissipated heat in the utilization heat exchanger 40 flows out to the liquid refrigerant pipe 52d. Note that the air heated by the heat exchanger 40 to be temperature-controlled is blown out into the air-conditioned space.

(2-2) Changer The changer 70 is a mechanism that changes the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 .

The change unit 70 includes a first bypass channel 80, a refrigerant container 72, a heat source side valve 82a, and a usage side valve 82b.

The first bypass channel 80 is a pipe that connects the heat source side end A of the main refrigerant circuit 50 and the utilization side end B of the main refrigerant circuit 50 . The heat source side end A is a portion of the liquid refrigerant pipe 52 d of the main refrigerant circuit 50 between the heat source heat exchanger 20 and the expansion mechanism 30 . A utilization side end B is a portion of the liquid refrigerant pipe 52 d of the main refrigerant circuit 50 between the utilization heat exchanger 40 and the expansion mechanism 30 .

A coolant container 72 , a heat source side valve 82 a and a usage side valve 82 b are arranged in the first bypass channel 80 .

The refrigerant container 72 is a container capable of storing a refrigerant inside.

The heat source side valve 82 a is arranged between the heat source side end A and the changing portion 70 . The usage-side valve 82 b is arranged between the usage-side end B and the changing section 70 . The heat source side valve 82a and the utilization side valve 82b are electronic expansion valves whose degree of opening is adjustable.

A method for changing the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 by the changing unit 70 will be described.

When the opening degrees of the heat source side valve 82a and the usage side valve 82b are adjusted during the operation of the refrigeration cycle apparatus 100, the refrigerant is stored in the refrigerant container 72 according to the opening degrees of the heat source side valve 82a and the usage side valve 82b. The ratio of the liquid phase to the gas phase of the refrigerant can be increased or decreased.

When the azeotropic refrigerant mixture or the pseudo-azeotropic refrigerant mixture exists in a gas-liquid two-phase state, the composition ratio of the gas-phase refrigerant and the composition ratio of the liquid-phase refrigerant are approximately the same.

On the other hand, when a non-azeotropic mixed refrigerant of a low boiling point refrigerant (first refrigerant) and a high boiling point refrigerant (second refrigerant) exists in a gas-liquid two-phase state, the high boiling point refrigerant is present in the liquid phase. The ratio becomes high, and the ratio of the low boiling point refrigerant becomes high in the gas phase portion. Therefore, if the opening degrees of the heat source side valve 82a and the usage side valve 82b are adjusted to change the amount of liquid-phase refrigerant and the amount of gas-phase refrigerant stored in the refrigerant container 72, The amount of first refrigerant applied can be increased or decreased. If the amount of the first refrigerant stored in the refrigerant container 72 is increased, the amount of the first refrigerant existing in the main refrigerant circuit 50 is reduced. can be enhanced. On the other hand, if the amount of the first refrigerant stored in the refrigerant container 72 is reduced, the amount of the first refrigerant existing in the main refrigerant circuit 50 will increase. can be lowered (the ratio of the first refrigerant is increased).

(2-3) Detection Section The detection section 150 detects the composition ratio of the first refrigerant and the second refrigerant in the refrigerant circulating in the main refrigerant circuit 50 .

The detection unit 150 includes a pipe 151 that connects between the heat source heat exchanger 20 and the expansion mechanism 30 and between the utilization heat exchanger 40 and the expansion mechanism 30 of the main refrigerant circuit 50 . The pipe 151 is used for detecting the composition of the refrigerant flowing through the main refrigerant circuit 50, and is not directly necessary for the vapor compression refrigeration cycle. The pipe 151 is a pipe having a smaller diameter than the liquid refrigerant pipe 52d, and a very small amount of refrigerant flows therethrough.

The detection unit 150 includes a coolant container 152 and a valve 154 arranged in the pipe 151 . Valve 154 includes a first valve 154a and a second valve 154b. The first valve 154 a is arranged between the connecting portion of the pipe 151 to the liquid refrigerant pipe 52 d between the heat source heat exchanger 20 and the expansion mechanism 30 and the refrigerant container 152 . The second valve 154 b is arranged between the connecting portion of the pipe 151 to the liquid refrigerant pipe 52 d between the utilization heat exchanger 40 and the expansion mechanism 30 and the refrigerant container 152 . The first valve 154a and the second valve 154b are, for example, electronic expansion valves with variable opening. However, it is not limited to this, and the first valve 154a and the second valve 154b may be capillary tubes, for example. The detection unit 150 has a pressure sensor 156 that measures the pressure of the refrigerant inside the refrigerant container 152 and a temperature sensor 158 that measures the temperature of the refrigerant inside the refrigerant container 152 .

During cooling operation or heating operation, the controller 110 opens the first valve 154a and the second valve 154b as necessary so that two-phase (liquid and gaseous) refrigerant exists in the refrigerant container 152. , the first valve 154a and the second valve 154b are controlled to a predetermined degree of opening. For example, when performing adsorption control and desorption control, the controller 110 opens the first valve 154 a and the second valve 154 b so that two-phase refrigerant is stored in the refrigerant container 152 . The valve 154b is controlled to a predetermined degree of opening.

For the non-azeotropic refrigerant mixture, the composition ratio can be calculated if the type of refrigerant used in the non-azeotropic refrigerant mixture and the pressure and temperature of the two-phase refrigerant are known. Therefore, the detection unit 150 determines the composition ratio of the refrigerant in the refrigerant container 152, in other words, the main The composition ratio between the first refrigerant and the second refrigerant in the refrigerant flowing through the liquid refrigerant pipe 52d of the refrigerant circuit 50 can be detected.

The composition ratio of the refrigerant is detected by the controller 110 functioning as part of the detection unit 150 and detecting the composition ratio of the refrigerant circulating in the main refrigerant circuit 50 based on the measurement results of the pressure sensor 156 and the temperature sensor 158. (Calculation) may be performed. Alternatively, the detection unit 150 may be a device independent of the controller 110 and detect the composition ratio of the refrigerant circulating in the main refrigerant circuit 50 based on the measurement results of the pressure sensor 156 and the temperature sensor 158 .

In this embodiment, the controller 110 detects the composition ratio of the refrigerant circulating through the main refrigerant circuit 50 based on the measurement results of the pressure sensor 156 and the temperature sensor 158 . Specifically, data representing the relationship between the pressure and temperature of the two-phase refrigerant and the composition ratio of the non-azeotropic refrigerant mixture (for example, tables and relational expressions) are stored. The controller 110 is based on the data stored in the memory representing the relationship between the pressure and temperature of the two-phase refrigerant and the composition ratio of the non-azeotropic refrigerant mixture, and the measurement results of the pressure sensor 156 and the temperature sensor 158. to detect the composition ratio of the refrigerant circulating in the main refrigerant circuit 50 .

Note that the method of detecting the composition ratio of the refrigerant circulating in the main refrigerant circuit 50 is not necessarily limited to the method exemplified here, and the detection unit 150 can be detected by another method or by using equipment different from the above method. may be used to detect the composition ratio of the refrigerant circulating in the main refrigerant circuit 50 .

(2-4) Controller The controller 110 is a control unit for controlling operations of various devices of the refrigeration cycle apparatus 100 .

The controller 110 mainly includes, for example, a microcontroller unit (MCU) and various electric circuits and electronic circuits (not shown). The MCU includes a CPU, memory, I/O interfaces, and the like. Various programs for the CPU of the MCU to execute are stored in the memory of the MCU. Also, an FPGA or an ASIC may be used for the controller 110 . Note that the various functions of the controller 110 do not need to be implemented by software, and may be implemented by hardware or through cooperation between hardware and software.

The controller 110 may be a device independent of the heat source unit 2 and the utilization unit 4 . Further, the controller 110 is not a device independent of the heat source unit 2 and the usage unit 4. For example, a controller (not shown) mounted on the heat source unit 2, a controller (not shown) mounted on the utilization unit 4, may function as the controller 110 by working together.

The controller 110 is electrically connected to the compressor 10, the flow path switching mechanism 15, and the expansion mechanism 30 of the main refrigerant circuit 50, and controls the operations of the compressor 10, the flow path switching mechanism 15, and the expansion mechanism 30. (See Figure 1). Further, the controller 110 controls the operation of a fan (not shown) that supplies air to the heat source heat exchanger 20 of the heat source unit 2 and a fan (not shown) that supplies air to the utilization heat exchanger 40 of the utilization unit 4. These fans are electrically connected. The controller 110 is also electrically connected to the heat source side valve 82a and the usage side valve 82b of the changing unit 70, and controls the operation of the heat source side valve 82a and the usage side valve 82b (see FIG. 1). Also, the controller 110 is electrically connected to the first valve 154a and the second valve 154b so as to control the operation of the first valve 154a and the second valve 154b of the detector 150 . Also, the controller 110 is electrically connected to the pressure sensor 156 and the temperature sensor 158 and can acquire the measured values of the pressure sensor 156 and the temperature sensor 158 . The controller 110 is also electrically connected to sensors (not shown) arranged at various locations in the refrigeration cycle apparatus 100 other than the pressure sensor 156 and the temperature sensor 158, and can acquire measurement values of these sensors.

The controller 110 executes various controls by, for example, the CPU executing programs stored in the memory. For example, the controller 110 controls operations of various devices of the refrigeration cycle device 100 when the refrigeration cycle device 100 performs cooling operation or heating operation. In addition, the controller 110 increases or decreases the rotation speed of the compressor 10 according to the required capacity of the refrigeration cycle device 100, or controls the operation of the change unit 70 to The composition ratio with the second refrigerant is changed.

Hereinafter, without mentioning the control of the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 by the changing unit 70, various devices of the refrigeration cycle device 100 during the cooling operation and the heating operation will be described. The basic operation of is explained.

After that, the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 using the control of the rotation speed of the compressor 10 according to the required capacity of the refrigeration cycle device 100 and the change unit 70 control (hereinafter sometimes referred to as composition ratio control to avoid complication of the description) will be described.

(2-5-1) Cooling operation The controller 110 performs the cooling operation when an instruction to perform the cooling operation is given from a remote controller (not shown) or when it is determined that the cooling operation needs to be performed in view of the temperature of the air-conditioned space. to run.

During cooling operation, the controller 110 controls the operation of the flow path switching mechanism 15 so that the heat source heat exchanger 20 functions as a refrigerant radiator and the utilization heat exchanger 40 functions as a refrigerant evaporator. The controller 110 also starts the operation of the compressor 10 and the fans mounted in the heat source unit 2 and the utilization unit 4 (not shown). In addition, the controller 110 controls the rotation speed of the motor 10a of the compressor 10, the heat source unit 2 and the utilization unit 4 based on the measurement values of various sensors of the refrigeration cycle apparatus 100, the target temperature of the air-conditioned space set by the user, and the like. The number of rotations of the fan mounted on the , and the opening degree of the electronic expansion valve as the expansion mechanism 30 are adjusted.

(2-5-2) Heating operation The controller 110 performs the heating operation when an instruction to perform the heating operation is given from a remote controller (not shown) or when it is determined that the heating operation needs to be performed in view of the temperature of the air-conditioned space. to run.

During heating operation, the controller 110 controls the operation of the flow path switching mechanism 15 so that the heat source heat exchanger 20 functions as a refrigerant evaporator and the utilization heat exchanger 40 functions as a refrigerant radiator. The controller 110 also starts the operation of the compressor 10 and the fans mounted in the heat source unit 2 and the utilization unit 4 (not shown). In addition, the controller 110 controls the rotation speed of the motor 10a of the compressor 10, the heat source unit 2 and the utilization unit 4 based on the measurement values of various sensors of the refrigeration cycle apparatus 100, the target temperature of the air-conditioned space set by the user, and the like. The number of rotations of the fan mounted on the , and the opening degree of the electronic expansion valve as the expansion mechanism 30 are adjusted.

Note that when frost formation on the heat source heat exchanger 20 is detected during heating operation, the controller 110 interrupts the heating operation, controls the operation of the flow path switching mechanism 15, and controls the flow direction of the refrigerant in the main refrigerant circuit 50. is switched in the same direction as during cooling operation to perform defrost operation (reverse cycle defrost operation). The defrost operation is an operation for removing frost adhering to the heat source heat exchanger 20 . Since the defrost operation of the refrigeration cycle device is generally known, the detailed description of the defrost operation will be omitted.

(2-5-3) Control of Compressor and Changer Dependent on Required Capability Control of compressor 10 and changer 70 according to the required capability of refrigeration cycle device 100, executed by controller 110, will be described below. .

First, before describing the control of the compressor 10 and the changing unit 70 according to the required capacity of the refrigeration cycle device 100, the controller 110 operates in a first mode in which the second refrigerant flows substantially independently in the main refrigerant circuit 50, and in a main mode. The reason for switching between the second mode in which the mixed refrigerant of the first refrigerant and the second refrigerant flows through the refrigerant circuit 50 will be described.

When using a second refrigerant (refrigerant with a high boiling point) such as R1234Ze or R1234yf, the refrigeration cycle device 100 can be operated relatively efficiently. However, if a high boiling point refrigerant is used, there is a possibility of insufficient performance during heating operation at low outside temperatures. On the other hand, by using a non-azeotropic mixed refrigerant in which a high boiling point refrigerant is mixed with a first refrigerant (low boiling point refrigerant) such as CO2, the lack of capacity can be compensated for. However, in the case of using a non-azeotropic mixed refrigerant in which the first refrigerant is mixed with the second refrigerant, there is a problem that the efficiency is lower than in the case of using the second refrigerant alone.

Therefore, the controller 110 operates in accordance with the required capacity of the refrigeration cycle apparatus 100 to operate in a first mode in which the second refrigerant is allowed to flow substantially solely through the main refrigerant circuit 50, and in which a mixture of the first refrigerant and the second refrigerant flows through the main refrigerant circuit 50. A second mode in which the coolant flows is switched and executed.

Specifically, the controller 110 executes the first mode during the cooling operation in which the required performance is relatively low and insufficient performance is unlikely to occur even if the second refrigerant is used substantially alone. Here, controller 110 does not execute the second mode during cooling operation. In short, the controller 110 executes the first mode when using the utilization heat exchanger 40 as an evaporator. Therefore, although detailed description is omitted, after execution of the second mode (for example, after execution of the second mode during heating operation, when composition ratio control for executing the first mode is not performed) 2), the controller 110 executes composition ratio control for allowing the second refrigerant to flow substantially solely through the main refrigerant circuit 50 at the start of the cooling operation.

On the other hand, the controller 110 executes the second mode during the heating operation in which the required capacity tends to be relatively large and there is a possibility that the capacity may be insufficient in the first mode. In short, the controller 110 executes the second mode when using the utilization heat exchanger 40 as a radiator.

As a control method, it is also possible to always execute the second mode during the heating operation.

However, even during the heating operation, it may be more efficient to execute the first mode. Description will be made with reference to FIG. FIG. 2 shows the change in COP when changing the capacity by changing the rotation speed of the motor 10a of the compressor 10, and the change in COP when changing the capacity by changing the ratio of the first refrigerant in the refrigerant. , is a diagram schematically showing. A solid line in FIG. 2 indicates a change in COP when the rotation speed of the motor 10a of the compressor 10 is increased to increase the capacity of the refrigeration cycle apparatus 100. As shown in FIG. A dashed line in FIG. 2 indicates a change in COP when the ratio of the first refrigerant in the refrigerant flowing through the main refrigerant circuit 50 is increased to increase the capacity of the refrigeration cycle device 100 . As can be seen from FIG. 2, up to a certain capacity value (see the two-dot chain line in the figure), it is better to increase the rotational speed of the motor 10a of the compressor 10 to obtain the capacity. 70 is used to control the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50) to secure the capacity.

Therefore, controller 110 does not always execute the second mode during heating operation (in other words, when utilizing heat exchanger 40 as a radiator), but according to the required capacity of refrigeration cycle device 100, It is preferable to execute the first mode or the second mode. Specifically, as described below with reference to FIGS. 3 and 4, the controller 110 can combine control of the rotational speed of the motor 10a of the compressor 10 and composition ratio control. preferable. FIG. 3 is an example of a flow chart of control performed when the refrigeration cycle apparatus 100 has insufficient capacity. FIG. 4 is an example of a flow chart of control performed when the refrigeration cycle apparatus 100 is overcapacity. The processes of FIGS. 3 and 4 are executed in parallel.

As a premise for the explanation, the position corresponding to the intersection of the line shown by the two-dot chain line in FIG. It is assumed that the rotation speed (upper limit rotation speed) of the motor 10a is obtained in advance. The upper limit rotation speed may be obtained by experiments using an actual machine, or may be obtained by simulation or theoretical calculation. The memory of the controller 110 stores the value of the upper limit rotation speed obtained in advance.

The controller 110 controls the rotation speed of the motor 10a of the compressor 10 according to the flowchart of FIG. Control the composition ratio.

In step S1 of the flow chart of FIG. 3, it is determined whether or not the required capacity cannot be achieved in the current operation (whether or not the capacity is insufficient). The determination of step S1 is repeatedly executed until it is determined that the ability is insufficient.

If it is determined that the capacity is insufficient, the process proceeds to step S2. In step S2, it is determined whether or not the current rotation speed of the motor 10a of the compressor 10 is the upper limit rotation speed. If it is determined that the rotation speed of the motor 10a of the compressor 10 has not reached the upper limit rotation speed, the process proceeds to step S3.

At step S<b>3 , the controller 110 increases the rotation speed of the motor 10 a of the compressor 10 . In step S3, the controller 110 may increase the rotational speed by a predetermined value, or may change the increment of the rotational speed according to the performance that is insufficient for the required performance. After performing step S3, the process returns to step S1.

On the other hand, when it is determined in step S2 that the rotation speed of the motor 10a of the compressor 10 has reached the upper limit rotation speed, the process proceeds to step S4. In step S<b>4 , the controller 110 performs composition ratio control to increase the ratio of the first refrigerant in the refrigerant flowing through the main refrigerant circuit 50 . In short, the controller 110 executes the second mode when the required capacity cannot be obtained even if the rotation speed of the compressor 10 is increased to a predetermined rotation speed (upper limit rotation speed) while executing the first mode, The changing unit 70 is controlled so that the mixed refrigerant of the first refrigerant and the second refrigerant flows through the main refrigerant circuit 50 . In step S4, the controller 110 may increase the ratio of the first refrigerant by a predetermined value (for example, increase by 2 wt%), or the ratio of the first refrigerant may may be determined by how much to increase

Specifically, in step S4, the controller 110 changes the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 detected by the detection unit 150 to the target composition ratio. The opening degrees of the heat source side valve 82a and the usage side valve 82b of the unit 70 are controlled. Then, when the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 detected by the detection unit 150 reaches the target composition ratio, the controller 110 opens the heat source side valve 82a and the utilization side valve 82b. close. After performing step S4, the process returns to step S1.

Note that when the process of step S4 is performed again after step S4 is performed, the controller 110 controls the operation of the changing unit 70 in the second mode so that the first refrigerant in the refrigerant flowing through the main refrigerant circuit 50 The composition ratio of the refrigerant and the second refrigerant is changed between the first composition ratio and the second composition ratio in which the ratio of the first refrigerant is higher than the first composition ratio. In this way, by changing the ratio of the first refrigerant stepwise, it is possible to secure the necessary capacity while suppressing the decrease in efficiency caused by using the refrigerant containing an excessive amount of the first refrigerant.

Controller 110 executes the process described in the flowchart of FIG. 4 in parallel with the process described in the flowchart of FIG. 3 during the heating operation. The controller 110 controls the rotational speed of the motor 10a of the compressor 10 according to the flow chart of FIG. , to control the composition ratio.

In step S11 of the flow chart of FIG. 4, it is determined whether or not the capacity is excessive with respect to the required capacity in the current operation. The determination of step S11 is repeatedly executed until it is determined that the capacity is excessive.

When it is determined that the capacity is excessive, the process proceeds to step S12. In step S12, it is determined whether or not the current ratio of the first refrigerant in the refrigerant flowing through the main refrigerant circuit 50 (in other words, the concentration of the first refrigerant) is the lower limit value. The lower limit value of the ratio of the first refrigerant is, for example, a predetermined concentration at which the controller 110 determines that the refrigerant flowing through the main refrigerant circuit 50 is substantially the single second refrigerant. In other words, at step S12, the controller 110 determines whether or not the mode being executed is the first mode.

If it is determined in step S12 that the ratio of the first refrigerant in the current refrigerant flowing through the main refrigerant circuit 50 is the lower limit value (if it is determined that the first mode is being executed), the process proceeds to step S13. . On the other hand, if it is determined that the current ratio of the first refrigerant in the refrigerant flowing through the main refrigerant circuit 50 is not the lower limit value, the process proceeds to step S14.

At step S<b>13 , the controller 110 reduces the rotation speed of the motor 10 a of the compressor 10 . In step S3, the controller 110 may reduce the rotation speed by a predetermined value, or may change how much the rotation speed is reduced according to the excess capacity with respect to the required capacity. After performing step S13, the process returns to step S11.

In step S<b>14 , the controller 110 performs composition ratio control to reduce the ratio of the first refrigerant in the refrigerant flowing through the main refrigerant circuit 50 . In step S14, the controller 110 may reduce the ratio of the first refrigerant by a predetermined value, or determine how much the ratio of the first refrigerant should be reduced according to the excess capacity with respect to the required capacity. You can change it.

Specifically, in step S14, the controller 110 changes the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 detected by the detection unit 150 to the target composition ratio. The opening degrees of the heat source side valve 82a and the usage side valve 82b of the unit 70 are controlled. Then, when the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 detected by the detection unit 150 reaches the target composition ratio, the controller 110 opens the heat source side valve 82a and the utilization side valve 82b. close. After performing step S14, the process returns to step S11.

(3) Features (3-1)
The refrigeration cycle device 100 includes a main refrigerant circuit 50, a changing section 70, and a controller 110 as an example of a control section. The main refrigerant circuit 50 uses a non-azeotropic mixed refrigerant containing a first refrigerant and a second refrigerant. The changing unit 70 changes the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 . Controller 110 controls the operation of changing unit 70 . Controller 110 executes a first mode and a second mode. The first mode is a mode in which the operation of the changing unit 70 is controlled to allow the second refrigerant to flow through the main refrigerant circuit 50 substantially independently. The second mode is a mode in which the operation of the changing unit 70 is controlled to allow the mixed refrigerant of the first refrigerant and the second refrigerant to flow through the main refrigerant circuit 50 .

The refrigeration cycle device 100 can use the second refrigerant substantially alone, or can use a non-azeotropic mixed refrigerant containing the first refrigerant and the second refrigerant. Refrigerants with different compositions can be used.

Preferably, in the refrigeration cycle apparatus 100, in the first mode, the main refrigerant circuit 50 is supplied with a refrigerant having a second refrigerant concentration of 92 wt % or higher.

More preferably, in the refrigeration cycle apparatus 100, in the first mode, the main refrigerant circuit 50 is supplied with a refrigerant having a second refrigerant concentration of 98 wt % or higher.

(3-2)
The refrigeration cycle device 100 includes a detection section 150 . The detection unit 150 detects the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 . The controller 110 controls the operation of the changing unit 70 so that the composition ratio of the first refrigerant and the second refrigerant detected by the detection unit 150 becomes the target composition ratio.

In the refrigerating cycle device 100, the composition ratio between the first refrigerant and the second refrigerant is changed while detecting the composition ratio of the refrigerant, so refrigerant with an appropriate composition can be used according to the operating conditions.

(3-3)
In the refrigeration cycle device 100, the boiling point of the second refrigerant is higher than the boiling point of the first refrigerant.

For example, specifically, the first refrigerant is CO2. The second refrigerant is R1234Ze or R1234yf.

(3-4)
In the refrigeration cycle apparatus 100, the main refrigerant circuit 50 includes the utilization heat exchanger 40 that adjusts the temperature of a temperature-adjusted object. When utilizing the utilization heat exchanger 40 as an evaporator, the controller 110 executes the first mode. When using the utilization heat exchanger 40 as a radiator, the controller 110 executes the second mode.

In the refrigeration cycle apparatus 100, when the utilization heat exchanger 40 is used as an evaporator, the second refrigerant can be used substantially alone to operate with an emphasis on efficiency. On the other hand, when the heat exchanger 40, which is likely to have insufficient capacity, is used as a radiator, the required capacity can be obtained by using the non-azeotropic mixed refrigerant of the first refrigerant and the second refrigerant. .

(3-5)
When the refrigerating cycle device 100 uses the utilization heat exchanger 40 as a radiator, the controller 110 executes the first mode or the second mode according to the required capacity of the refrigerating cycle device 100 .

In the refrigerating cycle device 100, even when the utilization heat exchanger 40 is used as a radiator, if it is not necessary to use the mixed refrigerant of the first refrigerant and the second refrigerant due to the capacity, the second refrigerant is used substantially independently. It can be used to drive with an emphasis on efficiency.

(3-6)
In refrigeration cycle device 100 , main refrigerant circuit 50 includes compressor 10 . Controller 110 controls the rotation speed of compressor 10 . The controller 110 executes the second mode when the required performance cannot be obtained even if the rotational speed of the compressor 10 is increased to a predetermined rotational speed (upper limit rotational speed) while the first mode is being executed.

The refrigeration cycle apparatus 100 can obtain the necessary capacity while suppressing a decrease in efficiency.

(3-7)
In the refrigeration cycle device 100, when the second mode is executed, the controller 110 controls the operation of the changing unit 70 to change the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50. , the first composition ratio and the second composition ratio. In the second composition ratio, the proportion of the first refrigerant is higher than in the first composition ratio.

In the refrigerating cycle device 100, the composition ratio between the first refrigerant and the second refrigerant is changed stepwise, so that it is possible to obtain the necessary capacity while suppressing a decrease in efficiency.

(3-8)
Refrigeration cycle device 100 includes compressor 10 in main refrigerant circuit 50 . Controller 110 controls the rotation speed of compressor 10 . The controller 110 controls either the rotational speed of the compressor 10 or the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 in accordance with changes in the required capacity of the refrigeration cycle device 100. to change

The refrigerating cycle device 100 can obtain the necessary capacity while suppressing a decrease in efficiency.

(3-9)
In the refrigeration cycle device 100, the controller 110 closes the main refrigerant circuit 50 when the ratio of the first refrigerant in the refrigerant flowing through the main refrigerant circuit 50 is higher than a predetermined value (lower limit) when the required capacity is reduced. The changing unit 70 is controlled to reduce the ratio of the first refrigerant in the flowing refrigerant, and when the ratio of the first refrigerant in the refrigerant flowing in the main refrigerant circuit 50 is equal to or less than a predetermined value (lower limit value), the compressor 10 Decrease the rpm.

The refrigerating cycle device 100 can obtain the necessary capacity while suppressing a decrease in efficiency.

(4) Modifications Modifications of the above embodiment will be described below. It should be noted that the following modified examples may be appropriately combined within a mutually consistent range.

(4-1) Modification A
The mechanism for changing the composition of the refrigerant flowing through the main refrigerant circuit 50 is not limited to the mechanism like the changing section 70 of the above embodiment. For example, the refrigeration cycle apparatus 100 may have a changing section 170 instead of the changing section 70 as shown in FIG.

The changing part 170 includes a container 172 filled with an adsorbent 172a instead of the refrigerant container 72 . Other configurations are the same as those of the changing unit 70 of the above embodiment.

The adsorbent 172a has the property of adsorbing the first refrigerant. Specifically, in the refrigeration cycle apparatus 100 of the first embodiment, the adsorbent 172a has the property of adsorbing CO2.

Also, the adsorbent 172a has a property of not adsorbing the second refrigerant. Specifically, in the refrigeration cycle apparatus 100 of the first embodiment, the adsorbent 172a does not adsorb R1234Ze or R1234yf used as the second refrigerant. Alternatively, the adsorbent 172a may adsorb the second refrigerant in addition to the first refrigerant, but may have a characteristic that the adsorption performance of the second refrigerant is lower than that of the first refrigerant.

Note that the adsorbent 172a is, for example, zeolite with high CO2 adsorption performance. Alternatively, the adsorbent 172a may be a metal-organic framework (MOF) having high CO2 adsorption performance. The type of the adsorbent 172a is the exemplified type if it adsorbs the first refrigerant and does not adsorb the second refrigerant or if the adsorption performance of the second refrigerant is lower than the adsorption performance of the first refrigerant. Not limited to materials.

In the changing unit 170 , when the adsorbent 172 a adsorbs the first refrigerant, the heat source side valve 82 a and the usage side valve 82 b are opened, and part of the refrigerant flowing through the main refrigerant circuit 50 flows into the container 172 . When the refrigerant passes through the container 172, the first refrigerant is adsorbed by the adsorbent 172a, while the second refrigerant is not or hardly adsorbed by the adsorbent 172a. becomes a refrigerant with a high ratio of By allowing this to flow into the main refrigerant circuit 50, the ratio of the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 can be increased.

On the other hand, also when the first refrigerant is desorbed from the adsorbent 172 a , the heat source side valve 82 a and the utilization side valve 82 b are opened, and part of the refrigerant flowing through the main refrigerant circuit 50 flows into the container 172 . At the time of desorption, the adsorbent 172a in the container 172 is further heated by using the heat of the high-temperature refrigerant discharged from the compressor 10, or by using the heat generated by the illustrated heater or the like. As a result, the first refrigerant is desorbed from the adsorbent 172a and mixed with the refrigerant flowing through the container 172, so that the refrigerant flowing out of the container 172 has a lower ratio of the second refrigerant (the ratio of the second refrigerant is lower than when it flowed into the container 172). low refrigerant ratio). By allowing this refrigerant to flow into the main refrigerant circuit 50, the ratio of the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 can be reduced. In other words, by causing this refrigerant to flow into the main refrigerant circuit 50, the ratio of the first refrigerant in the refrigerant flowing through the main refrigerant circuit 50 can be increased.

Furthermore, the configuration of the change unit is not limited to the illustrated one, and other configurations may be used as long as the composition ratio of the refrigerant flowing through the main refrigerant circuit 50 can be changed. For example, the modified section may utilize a refrigerant rectification tower.

(4-2) Modification B
In the above embodiment, the refrigeration cycle apparatus using a non-azeotropic refrigerant mixture in which the first refrigerant is CO2 and the second refrigerant is HFO refrigerant R1234Ze or R1234yf has been described. However, the types of the first refrigerant and the second refrigerant are not limited to the illustrated refrigerants. For example, the first refrigerant may be the HFO refrigerant R1132(E) (trans-1,2-difluoroethylene) or R1123 (trifluoroethylene). Even with such a combination of refrigerants, high-efficiency operation is realized by using the second refrigerant substantially alone, and if the capacity is insufficient when the second refrigerant is used alone, the first refrigerant Insufficient capacity can be compensated for by using a non-azeotropic mixture of refrigerant and the second refrigerant.

(4-3) Modification C
In the above embodiment, the refrigeration cycle device of the present disclosure is described by taking the refrigeration cycle device 100 installed in a building or the like as an example. However, the refrigeration cycle apparatus of the present disclosure is not limited to those installed in buildings. The refrigeration cycle device of the present disclosure may be, for example, a device mounted on a vehicle such as an automobile.

(4-4) Modification D
In the above-described embodiment, the refrigeration cycle device of the present disclosure is described by taking as an example the case where the refrigeration cycle device 100 includes the heat source unit 2 and the utilization unit 4 connected to the heat source unit 2 through refrigerant piping. However, the refrigeration cycle device of the present disclosure is not limited to such devices. For example, the refrigeration cycle apparatus of the present disclosure may be an integrated apparatus in which all devices are mounted in one casing.

(4-5) Modification E
In the above embodiment, the controller 110 executes the first mode in which the second refrigerant is used substantially alone when the utilization heat exchanger 40 is used as an evaporator. However, the controller 110 is not limited to this, and in addition to the first mode, the controller 110, when using the utilization heat exchanger 40 as an evaporator, if there is a condition that causes a problem of insufficient capacity, A second mode may be performed in which a non-azeotropic refrigerant mixture of the first refrigerant and the second refrigerant is used. In this case, the refrigeration cycle device may be a device that performs only the operation of cooling the temperature adjustment target.

(4-6) Modification F
In the above embodiment, the refrigeration cycle device 100 is a device capable of switching between an operation using the heat exchanger 40 as an evaporator and an operation using the heat exchanger 40 as a radiator. However, the refrigeration cycle device 100 is not limited to this, and may be a device that mainly performs only the operation using the utilization heat exchanger 40 as a radiator.

(4-7) Modification G
In the above embodiment, when increasing the capacity of the refrigeration cycle device 100 in accordance with changes in the required capacity, the controller 110 controls the rotation speed of the motor 10a of the compressor 10 and the composition ratio of the refrigerant flowing through the main refrigerant circuit 50. Of these, the one that can maintain a higher COP after the change is changed. Instead, when increasing the capacity of the refrigeration cycle device 100 in response to changes in the required capacity, the controller 110 changes the rotation speed of the motor 10a of the compressor 10 and the composition ratio of the refrigerant flowing through the main refrigerant circuit 50. Of these, the one with the lower power increase amount may be changed.

In order to perform such control, for example, the relationship between the capacity and the power consumption when the rotation speed of the motor 10a of the compressor 10 is changed, and the ratio of the first refrigerant of the refrigerant flowing through the main refrigerant circuit 50 is changed. The relationship between the capacity and the amount of power consumption when the engine is turned on may be obtained, and the upper limit rotation speed of the compressor, which serves as a threshold, may be determined in advance. The upper limit rotation speed is stored, for example, in the memory (storage unit) of the controller 110 .

In another example, as shown in FIG. 6, the compressor 10 may be provided with an ammeter or a watt-hour meter 10d. Then, when the demand for the refrigerating cycle device 100 increases, the controller 110 maintains the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 without changing the composition ratio of the motor 10a of the compressor 10. The change in the current value when the rotation speed is changed, and the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 is changed without changing the rotation speed of the motor 10a of the compressor 10. A change in the current value in each case may be actually measured. Then, the controller 110 may select, of the two controls, the one in which the current value of the compressor 10 actually increased less as the control to be finally executed.

(4-8) Modification H
In the above embodiment, the composition ratio between the first refrigerant and the second refrigerant is changed stepwise in the second mode, but it is not limited to this. For example, in the second mode, the controller 110 controls the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the main refrigerant circuit 50 to always be a predetermined (always the same) composition ratio. good.

<Appendix>
While embodiments and modifications of the present disclosure have been described above, it will be appreciated that various changes in form and detail are possible without departing from the spirit and scope of the present disclosure as defined in the claims. Will.

INDUSTRIAL APPLICABILITY The present disclosure is widely applicable and useful to refrigeration cycle devices.

10 compressor 40 utilization heat exchanger 50 main refrigerant circuit (refrigeration cycle)
70 change unit 100 refrigeration cycle device 110 controller (control unit)
150 detection unit 170 change unit

JP 2008-281326 A

Claims (11)

A refrigeration cycle device,
a refrigeration cycle (50) including a compressor (10) and using a non-azeotropic mixed refrigerant containing a first refrigerant and a second refrigerant having a boiling point higher than that of the first refrigerant ;
a changing unit (70, 170) that changes the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the refrigeration cycle;
a control unit (110) that controls the rotation speed of the compressor and the operation of the change unit;
with
The control unit controls the operation of the changing unit to allow the second refrigerant to flow substantially alone in the refrigerating cycle, and controls the operation of the changing unit to supply the first refrigerant to the refrigerating cycle. a second mode in which the mixed refrigerant with the second refrigerant flows;
The control unit executes the second mode when the required performance of the refrigeration cycle apparatus cannot be obtained even if the rotation speed of the compressor is increased to a predetermined rotation speed while the first mode is being executed. ,
A refrigeration cycle device (100). In the first mode, a refrigerant having a concentration of the second refrigerant of 92 wt% or more is passed through the refrigeration cycle,
The refrigeration cycle apparatus according to claim 1. In the first mode, a refrigerant having a concentration of 98 wt% or more of the second refrigerant is flowed through the refrigeration cycle,
The refrigeration cycle apparatus according to claim 2. further comprising a detection unit (150) for detecting the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the refrigeration cycle,
The control unit controls the operation of the changing unit so that the composition ratio of the first refrigerant and the second refrigerant detected by the detection unit becomes a target composition ratio.
The refrigeration cycle apparatus according to any one of claims 1 to 3. The refrigeration cycle includes a utilization heat exchanger (40) that adjusts the temperature of a temperature adjustment target,
When using the utilization heat exchanger as an evaporator, the control unit executes the first mode,
When the utilization heat exchanger is used as a radiator, the control unit cannot obtain the required capacity even if the rotation speed of the compressor is increased to a predetermined rotation speed while the first mode is being executed. executing the second mode if
The refrigeration cycle apparatus according to any one of claims 1 to 4 . When executing the second mode, the control unit controls the operation of the changing unit to change the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the refrigeration cycle to a first change between the composition ratio and a second composition ratio in which the ratio of the first refrigerant is higher than the first composition ratio;
The refrigeration cycle apparatus according to any one of claims 1 to 5 . The control unit adjusts the rotation speed of the compressor or the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the refrigeration cycle in accordance with the change in the required capacity. change the
The refrigeration cycle apparatus according to claim 6 . When the required capacity increases, the control unit changes the rotation speed of the compressor and the composition ratio of the first refrigerant and the second refrigerant in the refrigerant flowing through the refrigeration cycle. change the one with the smaller power increase amount of the compressor of
The refrigeration cycle apparatus according to claim 7 . If the ratio of the first refrigerant in the refrigerant flowing through the refrigerating cycle is higher than a predetermined value when the required capacity is lowered, the control unit controls the amount of the first refrigerant in the refrigerant flowing through the refrigerating cycle. controlling the changing unit to reduce the ratio, and reducing the rotation speed of the compressor when the ratio of the first refrigerant in the refrigerant flowing through the refrigeration cycle is equal to or less than the predetermined value;
The refrigeration cycle apparatus according to claim 7 or 8 . the first refrigerant is CO2,
The second refrigerant is R1234Ze or R1234yf,
The refrigeration cycle apparatus according to any one of claims 1 to 9 . the first refrigerant is R1132 (E) or R1123,
The second refrigerant is R1234Ze or R1234yf,
The refrigeration cycle apparatus according to any one of claims 1 to 9 .

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