JP2020003163A - Air conditioner - Google Patents

Abstract

To provide a refrigeration cycle device using a mixed refrigerant that has refrigerant performance equivalent to or higher than that of R407C refrigerant, a GWP (Global Warming Potential) lower than that of R410A refrigerant, and flammability lower than that of R32 refrigerant.SOLUTION: A refrigeration cycle device according to the present invention has a mixed refrigerant enclosed therein, which contains at least R32 refrigerant, R125 refrigerant and a third refrigerant. The third refrigerant has a saturated gas density of more than 24 kg/mat a saturation temperature of 10°C, a latent heat of vaporization of more than 90 kj/kg at a temperature of 10°C, nonflammability, and a GWP of 15 or less. The triple mixed refrigerant has the R32 refrigerant of 25 to 60 wt.%, the R125 refrigerant of 1 to 16 wt.%, and the third refrigerant of 31 to 69 wt.%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a refrigeration cycle device such as an air conditioner.

  R407C is used as a refrigerant flowing through a refrigerant circuit provided in a refrigeration cycle device such as an air conditioner (for example, Patent Document 1). R407C is a non-azeotropic refrigerant mixture composed of three components of R32, R125, and R134a, and has a lower heat transfer performance during a phase change than a single refrigerant or an azeotropic refrigerant. In addition, since the global warming potential (hereinafter, also referred to as GWP) is relatively high at 1770, conversion to a refrigerant having a low GWP is required. Recently, for example, an air conditioner using only R32 has been developed. R32 has a GWP of 675 and is relatively low, about 40% of R407C, but is classified as a slightly flammable refrigerant having a slight flammability.

  When R32 is used as a refrigerant for a home air conditioner, an explosion-proof design corresponding to its slight flammability is required. Further, since a large amount of refrigerant is used in a large-sized multi-air conditioner for a building, when the refrigerant leaks to the outside of the air conditioner during operation of the air conditioner or during maintenance work, there is a possibility that the damage may be increased.

  On the other hand, R410A is known as a refrigerant that can be used for an air conditioner. R410A is a nonflammable refrigerant, and is a pseudo-azeotropic mixed refrigerant, and has higher heat transfer performance than a non-azeotropic mixed refrigerant. However, R410A has a problem in terms of global warming because GWP is higher than 2090 and R407C.

JP-A-9-49667

  Therefore, it has been desired to develop a refrigerant having a GWP lower than that of R407C and a flammability lower than that of R32 while having a refrigerant performance equal to or higher than that of R407C.

  The present invention has been made in view of the above, and provides a refrigeration cycle apparatus using a mixed refrigerant having a refrigerant performance of R407C or higher, a GWP lower than R410A, and a flammability lower than R32. The purpose is to do.

In order to solve the above problems and achieve the object, a refrigeration cycle apparatus according to the present invention is a refrigeration cycle apparatus in which a mixed refrigerant containing at least R32, R125, and a third refrigerant is sealed, The refrigerant has a saturated gas density of more than 24 kg / m ³ when the saturation temperature is 10 ° C., has a latent heat of vaporization of more than 90 kJ / kg when the temperature is 10 ° C., has nonflammability, and has a GWP of 15 or less. Wherein the R32 is 25 to 60% by weight, the R125 is 1 to 16% by weight, and the third refrigerant is 31 to 69% by weight.

  Further, in the refrigeration cycle apparatus according to the present invention, in the above-described invention, the refrigeration cycle apparatus includes a heat exchanger, and a thickness of a heat transfer tube of the heat exchanger is such that the refrigeration cycle apparatus is filled with R407C as a refrigerant. The thickness is 1.25 to 1.35 times the thickness of the heat transfer tube of the heat exchanger at that time.

Further, in the refrigeration cycle apparatus according to the present invention, in the above-described invention, the refrigeration cycle apparatus includes a heat exchanger, and an inner diameter of a heat transfer tube of the heat exchanger is such that the refrigeration cycle apparatus has filled R407C as a refrigerant. 0.7 to 1.0 times the inner diameter of the heat transfer tube of the heat exchanger of the above,
It is characterized by the following.

  Further, in the refrigeration cycle device according to the present invention, in the above-described invention, the refrigeration cycle device includes a compressor, and the temperature of the refrigerant discharged from the compressor is set to a predetermined temperature under predetermined operation conditions. Control means for controlling the opening degree of the expansion device provided in the refrigeration cycle device is provided.

  Further, in the refrigeration cycle device according to the present invention, in the above-described invention, the refrigeration cycle device includes a compressor, and the lubricating oil sealed in the compressor is formed of a synthetic oil to which an extreme pressure additive is added. It is characterized by that.

  Further, in the refrigeration cycle device according to the present invention, in the above-described invention, the refrigeration cycle device includes a compressor, and a motor built in the compressor is a DC motor, and is driven by reluctance torque, and The permanent magnet of the motor is made of a rare earth magnet.

In the refrigeration cycle apparatus according to the present invention, in the invention described above, the refrigeration cycle apparatus includes a control device, and the maximum current capacity of the control device is controlled when the refrigeration cycle device has filled R407C as a refrigerant. Greater than the maximum current capacity of the device,
It is characterized by the following.

  Further, in the refrigeration cycle apparatus according to the present invention, in the above-described invention, the refrigeration cycle apparatus includes a compressor, and the excluded volume of the compressor is such that the refrigeration cycle apparatus is filled with R407C as a refrigerant. Smaller than the exclusion volume of

  Further, in the refrigeration cycle device according to the present invention, in the above-described invention, the pipe connected to the suction side of the compressor included in the refrigeration cycle device is not provided with a unit for detecting the temperature of the refrigerant, Features.

Further, in the refrigeration cycle apparatus according to the present invention, in the above-described invention, the heat source side heat exchanger included in the refrigeration cycle apparatus includes a leeward side flow path and a leeward side flow path arranged in the air flow direction,
When functioning as a condenser, the refrigerant flows through the leeward flow path and then through the leeward flow path, and when functioning as an evaporator, the refrigerant flows through the leeward flow path and then flows through the leeward flow path Characterized by flowing through.

  ADVANTAGE OF THE INVENTION According to the mixed refrigerant | coolant which concerns on this invention, it has the refrigerant | coolant performance more than R407C, GWP is lower than R410A, and the refrigeration cycle apparatus using the mixed refrigerant whose flammability is lower than R32 can be provided.

FIG. 1 is a composition diagram in triangular coordinates showing an embodiment of a mixed refrigerant filled in a refrigeration cycle apparatus according to the present invention. FIG. 2 is a schematic diagram illustrating refrigerant characteristics depending on the composition ratio of the mixed refrigerant charged in the refrigeration cycle apparatus according to the present invention. FIG. 3 is a schematic diagram illustrating refrigerant characteristics depending on the composition ratio of the mixed refrigerant filled in the refrigeration cycle apparatus according to the present invention. FIG. 4 is a refrigerant circuit diagram showing a refrigeration cycle apparatus according to the present invention. FIG. 5 is a perspective view showing a heat exchanger of the refrigeration cycle apparatus according to the present invention. FIG. 6 is a sectional view showing a heat transfer tube of the heat exchanger of the refrigeration cycle apparatus according to the present invention. FIG. 7 is a top view showing the heat exchanger of the refrigeration cycle apparatus according to the present invention. FIG. 8 is a sectional view showing a compressor of the refrigeration cycle apparatus according to the present invention.

  Hereinafter, embodiments of a mixed refrigerant according to the present invention and a refrigeration cycle apparatus (air conditioner) using the same will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the embodiment.

(Mixed refrigerant)
First, the mixed refrigerant according to the present invention will be described.
FIG. 1 is triangular coordinates representing the composition of the mixed refrigerant according to the present invention. The triangular coordinates are a graph in which each side of the equilateral triangle is represented as three items to be graphed, and the ratio of those items is represented by the length of a perpendicular from a point inside the equilateral triangle to each side. The triangular coordinates utilize the fact that the sum of perpendiculars from an arbitrary point inside the equilateral triangle to each side becomes a constant value, and this constant value corresponds to 100% which is the sum of the ratios of the three items. At this time, the three peaks indicate that R32 is 100% by weight, R125 is 100% by weight, and the third refrigerant (hereinafter, “α”) is 100% by weight, respectively. The mixed refrigerant according to the present invention is included in the range R in FIG. 1, and more specifically, contains 25 to 60% by weight of R32, 1 to 16% by weight of R125, and 31 to 69% by weight of α. It is a thing.

  Here, each refrigerant of R32, R125 and α has advantages and disadvantages in properties.

  R32 has a relatively low GWP of 675. Further, the latent heat of vaporization, which is one of the indexes of the refrigerant performance, is relatively good at 224.0 kJ / kg (when the saturation temperature is 45 ° C.). On the other hand, the burning speed, which is one of the indicators of flammability, has a high property of 6.7 cm / s. Further, the boiling point is -51.7 ° C.

  R125 has a very high GWP of 3500. The latent heat of vaporization, which is one of the indexes of the refrigerant performance, is 84.53 kJ / kg (when the saturation temperature is 45 ° C.). However, it has the property that it is an incombustible refrigerant (a combustion speed is 0 cm / s). Further, the boiling point is -48.1 ° C.

The condition of the refrigerant of α is as low as 15 with GWP. The refrigerant of α has a saturated gas density of more than 24 kg / m ³ when the saturation temperature is 10 ° C. The refrigerant of α has a latent heat of vaporization of 90 kJ / kg when the temperature is 10 ° C. Further, the refrigerant of α is assumed to have the property of a non-combustible refrigerant (combustion rate is 0 cm / s). For example, trifluoromethane iodide (CF ₃ I) corresponds to the refrigerant.

  Therefore, the mixed refrigerant of the present invention obtained by mixing the three types of refrigerants R32, R125, and α at a predetermined mixing ratio described later has a property derived from the properties of each refrigerant according to the mixing ratio of each refrigerant. Is shown.

  In FIG. 1, the position of R410A is shown in the middle of the right side of the triangular coordinates for reference. R410A is a mixed refrigerant containing 50% each of R32 and R125.

  The mixed refrigerant according to the present invention is located in a range R indicated by hatching in FIG. In the present invention, the refrigerant performance is based on R32 which is relatively good. However, in order to make the mixed refrigerant an incombustible refrigerant, R32 of the only flammable refrigerant is set to be 60% or less. R125 and α of the non-combustible refrigerant make up the remaining 40% or more.

Here, when the composition ratio of R125 increases, the GWP increases, and therefore, α containing a very low GWP is included. In this case, in order to reduce the GWP of the three types of mixed refrigerants to 750 or less, the composition ratio of α needs to be 31% or more. However, when the composition ratio of α is excessively increased, the volume capacity (unit is kJ / m ³ ) decreases. The composition ratio of α is limited to 69% or less so that the volume capacity does not become R407C or less. The reason why the GWP is set to 750 or less is based on the target value (GWP 750 or less in FY2020) set for the air conditioner manufacturer for stores and offices in the CFC emission control law enacted in April 2015.

  The volume capacity refers to the refrigerating capacity of the refrigerant per unit volume (unit suction amount of the compressor). If the volume capacity is small, it leads to an increase in the excluded volume. Also, the larger the displacement volume of the compressor, the greater the sliding loss and leakage loss. Therefore, in order to improve the performance of the refrigeration cycle device, it is desirable to use a refrigerant having a large volume capacity.

The volume capacity is calculated based on the cooling operation of the air conditioner at a condensing temperature of 50 ° C., an evaporating temperature of 10 ° C., a supercooling degree of 5K, a superheat degree of 0K, and a refrigeration capacity (unit: kJ / kg), and a suction density ( The unit is calculated by the product of kg / m ³ ). Considering the temperature gradient in the two-phase region of the non-azeotropic refrigerant mixture (temperature difference between dew point and boiling point at condensing pressure, temperature difference between dew point and boiling point at evaporating pressure), the condensing temperature is when the saturated liquid is 50 ° C. And the evaporation temperature were calculated as the pressure when the saturated steam was 10 ° C.

The volume capacity of R407C calculated under the above conditions was 4208 kJ / m ³ . When the composition ratio of α is 70%, the volume capacity of the mixed refrigerant is 4193 kJ / m ³ , which is lower than the volume capacity of R407C.

  FIG. 2 is a schematic diagram illustrating the refrigerant characteristics according to the composition ratio of the mixed refrigerant according to the present invention, and the table is rotated to the left by 90 degrees.

  In FIG. 2, the composition ratio of R32 is 25 to 60% by weight and R125 is 1 to 16% by weight, which corresponds to the mixed refrigerant according to the present invention. The leftmost column represents the refrigerant characteristic of R32 alone, the second column from the leftmost represents the refrigerant characteristic of R125 alone, and the third column from the leftmost represents the refrigerant characteristic of R410A.

  In order to make the refrigerant nonflammable, the ratio of R32, which is a flammable refrigerant, may be set to 60% or less.

  On the other hand, the GWP of R410A is 2088, but the present invention aims to significantly reduce the GWP (to 750 or less). If the composition ratio of R125 is 17% or more, the GWP becomes 766, so that the GWP cannot be reduced to 750 or less.

  On the other hand, when the volume capacity, which is one of the indexes of the refrigerant performance of the mixed refrigerant, is small, the heat transfer performance is reduced, and the performance of the air conditioner using the mixed refrigerant is greatly reduced. It is desirable that the volume capacity be higher than R407C.

  As described above, if a mixed refrigerant containing 25 to 60% by weight of R32, 1 to 16% by weight of R125, and 31 to 69% by weight of R32 has a refrigerant performance equal to or higher than that of R407C, and a GWP of 750 The following can provide a non-combustible mixed refrigerant. In the present embodiment, a three-component mixed refrigerant composed of only R32, R125, and α has been described. However, R32 is 25 to 60% by weight, R125 is 1 to 16% by weight, and α is 31 to 69% by weight. If it contains, the same effect can be exerted even if other refrigerants are contained. However, the fourth and subsequent refrigerants have a lower composition ratio than the three refrigerants (R32, R125, α). In addition, the fourth and subsequent refrigerants are evaluated for toxicity and flammability corresponding to ASHRAE34 refrigerant safety classification standards, and classified as A1 (low toxic, nonflammable) or A2L (low toxic, slightly flammable). Shall be limited to the used refrigerant. For example, R1234y, R1234ze (E), HFO-1123, and the like, which are HFO-based refrigerants, correspond to the fourth and subsequent refrigerants.

[Configuration of refrigeration cycle device]
Next, a refrigeration cycle device (air conditioner) according to the present invention will be described.
The air conditioner according to the present invention contains the above-described mixed refrigerant, that is, 25 to 60% by weight of R32, 1 to 16% by weight of R125, and 31 to 69% by weight of α as the refrigerant flowing through the refrigerant circuit. This uses a mixed refrigerant.

  FIG. 3 is a refrigerant circuit diagram showing a refrigeration cycle device according to the present invention. The refrigeration cycle apparatus 1 is applied to an air conditioner that cools and heats a room, and includes an outdoor unit 2 and an indoor unit 5 as shown in FIG. The outdoor unit 2 includes a rotary compressor 21, a four-way valve 22, an outdoor heat exchanger 23, a throttle device (decompressor) 24, and an outdoor unit controller 200.

  The rotary compressor 21 includes a discharge port 18 as a discharge unit and a suction port 19 as a suction unit. The rotary compressor 21 is controlled by the outdoor unit control unit 200 to compress the refrigerant supplied from the suction port 19 via the suction pipe 42 and the four-way valve 22, and to output the compressed refrigerant from the discharge port 18. Is supplied to the four-way valve 22 through the discharge pipe 41.

  The four-way valve 22 is connected to the discharge pipe 41 and the suction pipe 42, and is connected to the outdoor heat exchanger 23 via the refrigerant pipe 43 and to the indoor unit 5 via the refrigerant pipe 44. The indoor unit 5 and the outdoor heat exchanger 23 are connected via a refrigerant pipe 45. The four-way valve 22 switches the refrigeration cycle apparatus 1 between the heating mode and the cooling mode by being controlled by the outdoor unit control unit 200. When switched to the cooling mode, the four-way valve 22 supplies the refrigerant discharged from the rotary compressor 21 through the discharge pipe 41 to the outdoor heat exchanger 23, and transmits the refrigerant flowing out of the indoor unit 5 to the rotary compressor 21. It is supplied via a suction pipe 42. When switched to the heating mode, the four-way valve 22 supplies the refrigerant discharged from the rotary compressor 21 through the discharge pipe 41 to the indoor unit 5 and supplies the refrigerant flowing out of the outdoor heat exchanger 23 to the rotary compressor 21. It is supplied via a suction pipe 42.

  The outdoor heat exchanger 23 is connected to the expansion device 24 via a refrigerant pipe 45. An outdoor fan 27 is arranged near the outdoor heat exchanger 23. The outdoor fan 27 is rotated by a fan motor (not shown), thereby taking in outside air into the interior of the outdoor unit 2 and discharging the outside air that has exchanged heat with the refrigerant by the outdoor heat exchanger 23 to the outside of the outdoor unit 2. . In the cooling mode, the outdoor heat exchanger 23 exchanges heat between the refrigerant supplied from the four-way valve 22 and the outside air taken into the interior of the outdoor unit 2, and draws the heat-exchanged refrigerant into the expansion device 24. To supply. In the heating mode, the outdoor heat exchanger 23 exchanges heat between the refrigerant to which the refrigerant is supplied from the expansion device 24 and the outside air taken into the interior of the outdoor unit 2, and transfers the heat-exchanged refrigerant to the four-way valve 22. To supply.

  The expansion device 24 is connected to the indoor unit 5 via a refrigerant pipe 45. In the cooling mode, the expansion device 24 reduces the pressure of the refrigerant supplied from the outdoor heat exchanger 23 by adiabatically expanding the refrigerant, and supplies the low-temperature and low-pressure two-phase refrigerant to the indoor unit 5. In the heating mode, the expansion device 24 reduces the pressure of the refrigerant supplied from the indoor unit 5 by adiabatically expanding the refrigerant, and supplies the low-temperature and low-pressure two-phase refrigerant to the outdoor heat exchanger 23. Further, the expansion device 24 is controlled by the outdoor unit control section 200 to adjust the opening degree, and in the heating mode, adjusts the flow rate of the refrigerant supplied from the indoor unit 5 to the outdoor heat exchanger 23. In the case of the cooling mode, the flow rate of the refrigerant supplied from the outdoor heat exchanger 23 to the indoor unit 5 is adjusted.

  The indoor unit 5 includes an indoor heat exchanger 51, an indoor fan 55, and an indoor unit control unit 500. The indoor fan 55 is disposed in the vicinity of the indoor heat exchanger 51, and is rotated by a fan motor (not shown) to take in indoor air into the indoor unit 5, and cause the indoor heat exchanger 51 to control the refrigerant. Releases indoor air that has exchanged heat with the room. The indoor heat exchanger 51 is connected to the four-way valve 22 via a refrigerant pipe 44 and to the expansion device 24 of the outdoor unit 2 via a refrigerant pipe 45, respectively. The indoor heat exchanger 51 functions as an evaporator when the refrigeration cycle apparatus 1 is switched to the cooling mode, and functions as a condenser when the refrigeration cycle apparatus 1 is switched to the heating mode. That is, in the case of the cooling mode, the indoor heat exchanger 51 exchanges heat between the low-temperature and low-pressure two-phase refrigerant supplied from the expansion device 24 and the indoor air taken into the indoor unit 5. The heat-exchanged indoor air is discharged into the room, and the heat-exchanged refrigerant is supplied to the four-way valve 22. In the heating mode, the indoor heat exchanger 51 exchanges heat between the refrigerant supplied from the four-way valve 22 and the indoor air taken into the interior of the indoor unit 5, and transfers the heat-exchanged indoor air to the room. The refrigerant that has discharged and exchanged heat is supplied to the expansion device 24.

[Configuration of outdoor unit control unit]
The outdoor unit control unit 200 is configured by a so-called microcomputer, and includes a CPU (Central Processing Unit) (not shown), a storage device, and an input / output device. The CPU executes a computer program installed in the outdoor unit control unit 200 to control the storage device and the input / output device. Further, the CPU controls the rotary compressor 21, the four-way valve 22, the throttle device 24, the bypass valve 26, and the indoor unit control unit 500, respectively. The storage device stores a computer program. Information used by the CPU is recorded in the storage device. The computer program installed in the outdoor unit control unit 200 includes a plurality of computer programs for causing the outdoor unit control unit 200 to realize a plurality of functions.

  As described above, the refrigeration cycle apparatus 1 of the present embodiment is configured as a single type having one indoor unit 5 corresponding to one outdoor unit 2, but has a plurality of indoor units 5 corresponding to one outdoor unit 2. It may be configured as a multi-type. Further, the heat exchanger of the embodiment is applied to the refrigeration cycle apparatus 1 using the rotary compressor 21, but is not limited to the rotary compressor 21 and may be applied to a scroll compressor.

[Operation of refrigeration cycle device]
The user of the refrigeration cycle apparatus 1 activates the refrigeration cycle apparatus 1 by operating a remote controller (not shown) when adjusting the temperature of the room in which the indoor unit 5 is arranged, and the indoor unit control unit 500 Enter operating conditions. When the operating condition is input, the indoor unit control unit 500 transmits the input operating condition, the temperature of the indoor heat exchanger 51, and the indoor temperature to the outdoor unit control unit 200. The outdoor unit control unit 200 executes either the heating operation or the cooling operation based on the operating conditions received from the indoor unit control unit 500, the temperature of the indoor heat exchanger 51, and the indoor temperature. In FIG. 1, the flow of the refrigerant in the refrigerant circuit during the heating operation is indicated by arrows.

[Cooling operation]
When performing the cooling operation, the outdoor unit control unit 200 switches the four-way valve 22 to the cooling mode by controlling the four-way valve 22. The rotary compressor 21 controlled by the outdoor unit controller 200 compresses the gas refrigerant sucked from the four-way valve 22 through the suction pipe 42. The rotary compressor 21 discharges the compressed high-temperature and high-pressure gas refrigerant to the four-way valve 22. The four-way valve 22 supplies the high-temperature and high-pressure gas refrigerant discharged from the rotary compressor 21 to the outdoor heat exchanger 23 when being switched to the cooling mode. The outdoor heat exchanger 23 condenses and liquefies the high-temperature and high-pressure gas refrigerant by exchanging heat between the outside air taken into the outdoor unit 2 and the high-temperature and high-pressure gas refrigerant. The outdoor heat exchanger 23 supplies the high-pressure liquid refrigerant to the expansion device 24.

  The expansion device 24 adiabatically expands the high-pressure liquid refrigerant supplied from the outdoor heat exchanger 23 to a low-temperature, low-pressure two-phase refrigerant. The expansion device 24 supplies the low-temperature and low-pressure two-phase refrigerant to the indoor heat exchanger 51 of the indoor unit 5. The indoor heat exchanger 51 exchanges heat between the low-temperature and low-pressure two-phase refrigerant supplied from the expansion device 24 and the indoor air taken into the indoor unit 5 to convert the low-temperature and low-pressure two-phase refrigerant. Evaporate and gasify. The indoor heat exchanger 51 supplies the low-pressure gas refrigerant to the four-way valve 22. The four-way valve 22 supplies the low-pressure gas refrigerant flowing out of the indoor heat exchanger 51 to the rotary compressor 21 when the mode is switched to the cooling mode.

[Heating operation]
When performing the heating operation, the outdoor unit control unit 200 switches the four-way valve 22 to the heating mode by controlling the four-way valve 22. The rotary compressor 21 controlled by the outdoor unit controller 200 compresses the gas refrigerant sucked from the four-way valve 22 through the suction pipe 42. The rotary compressor 21 discharges the compressed high-temperature and high-pressure gas refrigerant to the four-way valve 22. The four-way valve 22 supplies the high-temperature and high-pressure gas refrigerant discharged from the rotary compressor 21 to the indoor unit 5 when being switched to the heating mode. The indoor heat exchanger 51 of the indoor unit 5 exchanges heat between the high-temperature and high-pressure gas refrigerant supplied to the indoor unit 5 from the four-way valve 22 and the indoor air taken into the indoor unit 5. A high-temperature and high-pressure gas refrigerant is condensed and liquefied. The indoor heat exchanger 51 supplies the high-pressure liquid refrigerant to the expansion device 24.

  The expansion device 24 adiabatically expands the high-pressure liquid refrigerant supplied from the indoor heat exchanger 51 into a low-temperature, low-pressure two-phase refrigerant. The expansion device 24 supplies the low-temperature and low-pressure two-phase refrigerant to the outdoor heat exchanger 23. The outdoor heat exchanger 23 evaporates the low-temperature and low-pressure refrigerant by exchanging heat between the outside air taken into the interior of the outdoor unit 2 and the low-temperature and low-pressure two-phase refrigerant supplied from the expansion device 24. Gasify. The outdoor heat exchanger 23 supplies a low-pressure gas refrigerant to the four-way valve 22. The four-way valve 22 supplies the low-pressure gas refrigerant flowing out of the outdoor heat exchanger 23 to the rotary compressor 21 when the mode is switched to the heating mode.

  When R407C is used as the refrigerant, the temperature gradient generated at the time of the phase change becomes large, which has an effect when controlling the opening degree of the expansion device 24. The opening degree of the expansion device 24 is controlled such that the degree of superheating of the refrigerant sucked into the rotary compressor 21 becomes an optimum value. The suction superheat degree is calculated by subtracting the evaporator intermediate temperature (the temperature of the refrigerant during the evaporation process) from the evaporator outlet temperature (the temperature of the refrigerant sucked into the rotary compressor 21). In the case of a single refrigerant or an azeotropic refrigerant, the degree of superheat of refrigerant sucked into the rotary compressor 21 can be estimated from the evaporation temperature and the temperature (discharge temperature) of the refrigerant discharged from the rotary compressor 21. Therefore, there is no need to provide a temperature sensor for detecting the temperature of the refrigerant between the four-way valve 22 and the suction port 19 of the rotary compressor 21.

  However, in the case of a refrigerant such as R407C, the temperature rises in the process of evaporating, and the degree of superheat of the refrigerant sucked into the rotary compressor 21 becomes insufficient (not optimal) with respect to the target value. However, the apparent degree of superheating of the intake air becomes an appropriate value. Therefore, for a refrigerant such as R407C, it is necessary to detect the evaporator outlet temperature (the temperature of the refrigerant sucked into the rotary compressor 21). On the other hand, since the temperature gradient of the mixed refrigerant filled in the refrigeration cycle apparatus of the present invention is smaller than that of R407C, the temperature of the refrigerant is detected between the four-way valve 22 and the suction port 19 of the rotary compressor 21. There is no need to provide a temperature sensor that operates.

  Further, the outdoor unit control unit 200 performs the throttling device 24 based on the operating conditions received from the indoor unit control unit 500, the temperature of the indoor heat exchanger 51, and the indoor temperature when performing the heating operation or the cooling operation. Adjust the opening of. For example, when the outdoor unit 2 and the indoor unit 5 are operating, the outdoor unit control unit 200 rotates the rotary unit based on the operating conditions received from the indoor unit control unit 500, the temperature of the indoor heat exchanger 51, and the indoor temperature. When it is determined that the temperature (discharge temperature) of the refrigerant discharged from the compressor 21 is high, the opening degree of the expansion device 24 is increased by controlling the expansion device 24.

  Note that the mixed refrigerant charged in the refrigeration cycle device of the present invention has the same latent heat enthalpy under the condition that the condensing temperature at the time of cooling becomes higher than that of R407C (for example, a high outside air temperature condition). It is necessary to increase the circulation amount in order to maintain the cooling capacity. In order to increase the circulation amount, it is preferable that the maximum current capacity of the outdoor unit control unit 200 is large. Therefore, the maximum current capacity of the outdoor unit control unit 200 in the refrigeration cycle device of the present embodiment is larger than the maximum current capacity of the outdoor unit control unit when the refrigeration cycle device of this embodiment has filled R407C as a refrigerant.

[Configuration of heat exchanger]
FIG. 4 is a perspective view illustrating the outdoor heat exchanger 23 of the embodiment. The heat exchanger of the embodiment is provided in the refrigeration cycle apparatus 1 as the outdoor heat exchanger 23 and the indoor heat exchanger 51. As shown in FIG. 4, the outdoor heat exchanger 23 includes a pair of side plates 231-1 and 231-2, a heat transfer tube 232, and a plurality of fins 233. Each of the pair of side plates 231-1 and 231-2 is formed in a plate shape. The pair of side plates 231-1 and 231-2 are arranged along both ends in the stacking direction of the plurality of fins 233, and are supported by the outdoor unit 2. A plurality of through holes are formed in the side plates 231-1 and 231-2.

  FIG. 4 shows an example of the shape of the heat exchanger when applied as the outdoor heat exchanger 23, and is not limited to this shape. For example, when applied to the indoor heat exchanger 51, it is formed in a shape of a heat exchanger that matches the form of the indoor unit 5.

  The heat transfer tube 232 is formed to be a single circular tube. The heat transfer tube 232 meanders between the pair of side plates 231-1 and 231-2, and includes a plurality of straight portions and a plurality of bent portions. Two straight portions of the plurality of straight portions are connected to each of the plurality of bent portions. The heat transfer tubes 232 are supported by the side plates 231-1 and 231-2 by inserting a plurality of straight portions along a plurality of through holes formed in the pair of side plates 231-1 and 231-2. Have been. One end of the heat transfer tube 232 is connected to the four-way valve 22 via the refrigerant pipe 43, and the other end is connected to the expansion device 24 via the refrigerant pipe 45.

  FIG. 5 is a cross-sectional view showing a heat transfer tube included in the outdoor heat exchanger 23 of the embodiment.

  As shown in FIG. 5, the thickness of the heat transfer tube 232 in the radial direction is H [mm], and the inner diameter of the heat transfer tube 232 is φB [mm]. In the manufacturing process of the heat transfer tube 232, the heat transfer tube 232 is expanded to a desired outer diameter. The above-described equation 1 indicates the dimension of the heat transfer tube 232 after expansion. Since the pressure of the mixed refrigerant filled in the refrigeration cycle device of the present invention at the same temperature is higher than that of R407C (increased by about 30%), the pressure of the refrigerant is increased by increasing the thickness of the heat transfer tube. Needs to be improved. Therefore, the thickness of the heat transfer tube 232 in the refrigeration cycle device of the present embodiment is 1.25 to 1.35 times the thickness of the heat transfer tube when the refrigeration cycle device of the present embodiment encloses R407C as a refrigerant. Is preferred.

Alternatively, the pressure resistance can be improved by reducing the inner diameter of the heat transfer tube 232 without increasing the wall thickness. Therefore, the inner diameter of the heat transfer tube 232 in the refrigeration cycle device of the present embodiment is 0.7 to 1.0 of the inner diameter of the heat transfer tube of the refrigeration cycle device in which R407C is sealed as a refrigerant, corresponding to the refrigeration cycle device of the present embodiment. Preferably it is twice. Further, the latent refrigerant enthalpy of the mixed refrigerant filled in the refrigeration cycle apparatus of the present invention is lower under the condition where the condensing temperature during cooling is higher than that of R407C (for example, under the condition of high outside air temperature). As a result, the cooling capacity is reduced. Therefore, a microchannel heat exchanger (for example, a parallel flow heat exchanger using a flat perforated tube as a heat transfer tube) having a high KA value (heat transmittance × surface area) as a performance index of the heat exchanger is used as the outdoor heat exchanger 23. By using the refrigeration cycle apparatus of the present invention, a decrease in the cooling capacity can be suppressed as compared with R407C.

  FIG. 6 is a top view illustrating the outdoor heat exchanger 23 of the embodiment. In the outdoor heat exchanger 23 (heat source side heat exchanger) of the embodiment, as shown in FIG. 6, the leeward passage 23 a and the leeward passage 23 b are arranged side by side in the air flow direction D. . In the case where the refrigerant functions as a condenser (when the refrigerant flows from the refrigerant pipe 43 to the refrigerant pipe 45), the refrigerant flows through the leeward flow path 23b before flowing through the leeward flow path 23a. In the case where the refrigerant functions as an evaporator (when the refrigerant flows from the refrigerant pipe 45 to the refrigerant pipe 43), the refrigerant flows in the leeward channel 23b after flowing in the leeward channel 23a.

  When the outdoor heat exchanger 23 functions as an evaporator, the air passing through the leeward passage 23b has already exchanged heat with the refrigerant in the leeward passage 23a. Similarly, the refrigerant passing through the leeward passage 23b has already been heat-exchanged with air in the leeward passage 23a. Therefore, when a refrigerant having a large temperature gradient such as R407C is used, the temperature difference tends to be reduced in the process of flowing through the heat transfer tube. Therefore, in a refrigeration cycle device in which R407C is sealed as a refrigerant, a bridge circuit or the like is formed so that the refrigerant flows during the cooling operation in the same direction as that during the heating operation (the direction in which the refrigerant flows from the refrigerant pipe 43 to the refrigerant pipe 45). It was necessary to form it. On the other hand, the mixed refrigerant filled in the refrigeration cycle apparatus of the present invention has a smaller temperature gradient than R407C, so that a temperature difference can be ensured even in a parallel flow.

[Rotary compressor]
FIG. 7 is a cross-sectional view illustrating the rotary compressor 21 of the embodiment. As shown in FIG. 2, the rotary compressor 21 is a high-pressure dome type compressor including a compressor housing 10, a shaft 15, a motor unit 11, and a compressor unit 12. The compressor housing 10 is formed in a substantially cylindrical shape, and forms an internal space 16 that is sealed from the environment in which the compressor 21 is installed. The internal space 16 is formed in a substantially columnar shape. The compressor housing 10 is arranged such that the axis of the cylinder of the internal space 16 is parallel to the vertical direction when the compressor housing 10 is placed vertically on a horizontal plane. The compressor housing 10 has an oil reservoir 17 formed below the internal space 16. The oil sump 17 stores lubricating oil for lubricating the compressor unit 12. In the compressor housing 10, the internal space 16 is connected to the suction pipe 42 and the discharge pipe 41. The suction pipe 42 includes a first suction pipe 421 and a second suction pipe 422. The shaft 15 is formed in a rod shape, and is disposed in the internal space 16 of the compressor housing 10. The shaft 15 is supported by the compressor housing 10 so as to be rotatable around a rotation axis that is parallel to the axis of a cylinder formed by the internal space 16.

[Motor part]
The motor unit 11 is arranged in an upper part of the internal space 16. The motor unit 11 includes a rotor 112 and a stator 111. The rotor 112 is formed in a substantially cylindrical shape, and is fixed to the shaft 15. The stator 111 is formed in a substantially cylindrical shape, is disposed so as to surround the rotor 112, and is fixed to the compressor housing 10. The stator 111 has a stator core 113 and a plurality of windings 114. The plurality of windings 114 are respectively wound around a plurality of teeth formed on the stator core 113.

  The motor unit 11 is configured by a brushless DC motor, and is configured to be driven by reluctance torque. Further, the permanent magnet of the rotor 112) is made of a rare earth magnet. The mixed refrigerant filled in the refrigeration cycle device of the present invention has a higher refrigerant temperature inside the rotary compressor 21 than R407C.

  In the case of a DC motor, a permanent magnet such as ferrite or rare earth is used for the motor. For this reason, almost no induced current is generated in the permanent magnet portion, so that even if the motor temperature rises and the electric resistance of the permanent magnet portion rises, no loss occurs. Therefore, in the DC motor, a decrease in motor efficiency due to a rise in temperature is small. Therefore, when a refrigerant having a high discharge temperature such as a mixed refrigerant charged in the refrigeration cycle device of the present invention is used, a DC motor is suitable. In particular, rare earth magnets have a small decrease in magnetic force with temperature rise. Therefore, a DC motor using a rare earth as a magnet material is suitable for a refrigerant having a high discharge temperature. Further, among DC motors, it is preferable to use reluctance torque to improve efficiency. In other words, while the torque of the permanent magnet decreases as the temperature rises, this reluctance torque keeps a constant value regardless of the temperature rise. Therefore, when using a refrigerant having a high discharge temperature, such as a mixed refrigerant filled in the refrigeration cycle apparatus of the present invention, a DC motor using reluctance torque is suitable.

  The motor unit 11 causes the stator 111 to generate a rotating magnetic field by applying a three-phase current to the plurality of windings 114. The rotor 112 rotates the shaft 15 by the rotating magnetic field generated by the stator 111. That is, the motor unit 11 rotates the shaft 15 by applying a three-phase current to the plurality of windings 114. When an open-phase current lacking one or two phases out of the three-phase current is applied to the plurality of windings 114, the motor unit 11 does not cause the stator 111 to generate a rotating magnetic field and prevent the shaft 15 from rotating. During operation stop of the refrigeration cycle apparatus 1, the motor unit 11 generates heat by applying an open-phase current to the plurality of windings 114, and causes the refrigerant and the lubricating oil in the internal space 16 of the compressor housing 10 to generate heat. Heat. The lubricating oil is preferably a synthetic oil to which an extreme pressure additive has been added. This is because the mixed refrigerant filled in the refrigeration cycle apparatus of the present invention has a higher refrigerant temperature inside the rotary compressor 21 than R407C, and therefore, a later-described compressor unit 12 and the like of the rotary compressor 21 due to thermal expansion due to high temperature or the like. This is to reduce the wear on the sliding part of. As the extreme pressure additive, phosphorus-based ones such as phosphate ester and phosphite ester, and chlorine-based and sulfur-based ones are used.

[Compressor section]
The compressor section 12 includes a first compression section 12S and a second compression section 12T. The first compression section 12S includes a first cylinder 121S and a first annular piston 125S, and includes a first vane (not shown). The first cylinder 121S forms a first cylinder chamber 130S. The first annular piston 125S is disposed in the first cylinder chamber 130S, and is fixed to the shaft 15. The first vane is movably supported by the first cylinder chamber 130S, and divides a working chamber formed between the first cylinder 121S and the first annular piston 125S into a suction chamber and a compression chamber. The suction chamber is not connected to the internal space 16 of the compressor housing 10, but is connected to a first suction pipe 421 of the suction pipe 42. The volume of the suction chamber expands due to rotation of the shaft 15, and after the suction chamber expands to a predetermined volume (exclusion volume), the suction chamber transits to the compression chamber. The compression chamber is not connected to the two suction pipes 42 but is connected to the internal space 16 of the compressor housing 10. The volume of the compression chamber is reduced by the rotation of the shaft 15, and after the compression chamber is reduced to a predetermined volume, the compression chamber transitions to the suction chamber. In the mixed refrigerant filled in the refrigeration cycle apparatus of the present invention, the density of the refrigerant drawn into the rotary compressor 21 becomes higher than that of R407C. May be small. By reducing the excluded volume, the compressor can be downsized.

  The second compression section 12T is formed substantially in the same manner as the first compression section 12S, and is disposed above the first compression section 12S. The second compression section 12T includes a second cylinder 121T and a second annular piston 125T, and includes a second vane (not shown). The second cylinder 121T forms a second cylinder chamber 130T. The second annular piston 125T is disposed in the second cylinder chamber 130T, and is fixed to the shaft 15 so that a phase difference of 180 ° with the second annular piston 125T is formed with respect to the shaft 15. The second vane is movably supported by the second cylinder chamber 130T, and divides a working chamber formed between the second cylinder 121T and the second annular piston 125T into a suction chamber and a compression chamber. The suction chamber is not connected to the internal space 16 of the compressor housing 10 but is connected to the second suction pipe 422 of the two suction pipes 42. The rotation of the shaft 15 causes the suction chamber to expand in volume, and after expanding to a predetermined volume, transitions to the compression chamber. The compression chamber is not connected to the two suction pipes 42 but is connected to the internal space 16 of the compressor housing 10. The volume of the compression chamber is reduced by the rotation of the shaft 15, and after the compression chamber is reduced to a predetermined volume, the compression chamber transitions to the suction chamber.

DESCRIPTION OF SYMBOLS 1 Refrigeration cycle apparatus 10 Compressor housing 11 Motor part 111 Stator 112 Rotor 113 Stator core 114 Winding (115 winding temperature sensor)
12 compressor section 12S first compression section 121S first cylinder 125S first annular piston 130S first cylinder chamber 12T second compression section 121T second cylinder 125T second annular piston 130T second cylinder chamber 15 shaft 16 internal space 17 Oil reservoir 18 Discharge port 19 Suction port 2 Outdoor unit 200 Outdoor unit control unit 21 Rotary compressor 22 Four-way valve 23 Outdoor heat exchanger 231-1 Side plate 231-2 Side plate 232 Heat transfer tube 233 Fin 24 Throttle device (decompressor)
27 outdoor fan 41 discharge pipe 42 suction pipe 421 first suction pipe 422 second suction pipe 43 refrigerant pipe 44 refrigerant pipe 45 refrigerant pipe 5 indoor unit 500 indoor unit control unit 51 indoor heat exchanger 55 indoor fan

Claims (10)

A refrigeration cycle device containing a mixed refrigerant containing at least R32, R125, and a third refrigerant,
The third refrigerant has a saturated gas density of more than 24 kg / m ^{3 at} a saturation temperature of 10 ° C., an evaporation latent heat of more than 90 kJ / kg at a temperature of 10 ° C., and has nonflammability, and GWP is 15 or less,
In the three-type mixed refrigerant, R32 is 25 to 60% by weight, R125 is 1 to 16% by weight, and the third refrigerant is 31 to 69% by weight.
A refrigeration cycle device characterized by the above-mentioned. The refrigeration cycle device includes a heat exchanger, and the thickness of the heat transfer tube of the heat exchanger is 1.25 of the thickness of the heat transfer tube of the heat exchanger when the refrigeration cycle device is filled with R407C as a refrigerant. Times to 1.35 times,
The refrigeration cycle apparatus according to claim 1, wherein: The refrigeration cycle apparatus includes a heat exchanger, and the inner diameter of the heat transfer tube of the heat exchanger is 0.7 times or more the inner diameter of the heat transfer tube of the heat exchanger when the refrigeration cycle apparatus is filled with R407C as a refrigerant. 1.0 times,
The refrigeration cycle apparatus according to claim 1 or 2, wherein: The refrigeration cycle device includes a compressor, and a control unit that controls an opening degree of a throttle device included in the refrigeration cycle device so that a temperature of the refrigerant discharged from the compressor becomes a predetermined temperature under a predetermined operation condition. To provide,
The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein: The refrigeration cycle device includes a compressor, the lubricating oil sealed in the compressor is composed of synthetic oil to which an extreme pressure additive has been added,
The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein: The refrigeration cycle device includes a compressor, the motor built in the compressor is a DC motor, and is driven by reluctance torque, and the permanent magnet of the motor is composed of a rare earth magnet,
The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein: The refrigeration cycle device includes a control device, the maximum current capacity of the control device is larger than the maximum current capacity of the control device when the refrigeration cycle device has filled R407C as a refrigerant,
The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein: The refrigeration cycle device includes a compressor, the displacement volume of the compressor is smaller than the displacement volume of the compressor when the refrigeration cycle device sealed R407C as a refrigerant,
The refrigeration cycle apparatus according to any one of claims 1 to 7, wherein: The refrigeration cycle device includes a compressor, the pipe connected to the suction side of the compressor is not provided with a means for detecting the temperature of the refrigerant,
The refrigeration cycle apparatus according to any one of claims 1 to 8, wherein: The heat source side heat exchanger included in the refrigeration cycle device, the leeward side flow path and the leeward side flow path are arranged side by side in the air flow direction,
In the case of functioning as a condenser, the medium flows through the leeward flow path 23b and then flows through the leeward flow path 23a,
When functioning as an evaporator, the refrigerant is caused to flow through the leeward passage 23b after flowing through the leeward passage 23a.
The refrigeration cycle apparatus according to any one of claims 1 to 9, wherein:

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