阅读说明：本技术 制冷循环装置 (Refrigeration cycle device ) 是由 梁池悟 野本宗 筑山亮 石川智隆 藤本肇 池田隆 佐多裕士 于 2018-09-28 设计创作，主要内容包括：在制冷循环装置中,非共沸混合制冷剂或特定制冷剂按压缩机、第一热交换器、温度式膨胀阀(3)及第二热交换器的顺序循环。在感温筒(6)中封入有特定制冷剂。特定制冷剂是单一制冷剂或近共沸混合制冷剂。感温筒(6)被配置成从被吸入压缩机的非共沸混合制冷剂接受热。温度式膨胀阀(3)包含框体(30)、间隔件(31)、基体(35)、阀芯(33)及弹簧(34)。感温筒(6)与第一空间(S1)连通。第二热交换器与压缩机之间的流路与第二空间(S2)连通。温度式膨胀阀(3)构成为能够调节特定方向上的基体(35)从基准位置(Z0)起的位移量(s0)与弹簧(34)的弹簧系数之积。(In the refrigeration cycle device, a non-azeotropic refrigerant mixture or a specific refrigerant circulates in the order of a compressor, a first heat exchanger, a temperature expansion valve (3), and a second heat exchanger. A specific refrigerant is sealed in the temperature sensing cylinder (6). The particular refrigerant is a single refrigerant or a near-azeotropic refrigerant mixture. The temperature-sensing cylinder (6) is configured to receive heat from a zeotropic refrigerant mixture sucked into the compressor. The thermal expansion valve (3) includes a frame (30), a spacer (31), a base (35), a valve element (33), and a spring (34). The temperature sensing cylinder (6) communicates with the first space (S1). The flow path between the second heat exchanger and the compressor communicates with the second space (S2). The thermal expansion valve (3) is configured so as to be able to adjust the product of the amount (s0) of displacement of the base (35) from the reference position (Z0) in a specific direction and the spring constant of the spring (34).)

1. A refrigeration cycle apparatus capable of using a non-azeotropic mixture refrigerant and a specific refrigerant, wherein,

the refrigeration cycle device is provided with:

a compressor;

a first heat exchanger;

a temperature type expansion valve;

a second heat exchanger; and

a temperature-sensitive cylinder in which the specific refrigerant is sealed,

the non-azeotropic mixture refrigerant or the specific refrigerant circulates in the order of the compressor, the first heat exchanger, the temperature-type expansion valve, and the second heat exchanger,

the specific refrigerant is a single refrigerant or a near azeotropic mixture refrigerant,

the temperature sensing cylinder is configured to receive heat from refrigerant drawn into the compressor,

the temperature type expansion valve includes:

a frame body;

a spacer that divides the frame into a first space and a second space and is movable in a specific direction;

a substrate;

a spool that is integrally movable with the spacer in the specific direction with respect to the base body; and

a spring having a first end fixed to the valve element and a second end fixed to the base, and extending and contracting in the specific direction,

the temperature sensing cylinder is communicated with the first space,

a flow path between the second heat exchanger and the compressor communicates with the second space,

the thermal expansion valve is configured to be capable of adjusting a product of a displacement amount of the base from a reference position in the specific direction and a spring constant of the spring.

2. The refrigeration cycle apparatus according to claim 1,

the range of the evaporation temperature and the range of the degree of superheat of the refrigerant drawn into the compressor, which are assumed in the refrigeration cycle device, are a first range and a second range,

in the case where the specific refrigerant is circulated in the refrigeration cycle device, the product required to set the evaporation temperature to the first range and set the degree of superheat to the second range is a first value,

when the non-azeotropic refrigerant mixture is circulated in the refrigeration cycle apparatus, the volume is a second value,

the ratio of the difference between the first value and the second value to the first value is-78% or more and-1% or less.

3. The refrigeration cycle apparatus according to claim 2,

the position of the substrate can be adjusted in the specific direction,

setting the evaporation temperature to the first range and the degree of superheat to the position of the base body required in the second range as a first position when the specific refrigerant is circulated in the refrigeration cycle device,

when the non-azeotropic mixture refrigerant is circulated in the refrigeration cycle apparatus, the position of the base is the second position,

the ratio of the difference between a first displacement amount of the first position from the reference position and a second displacement amount of the second position from the reference position to the first displacement amount is-78% or more and-1% or less.

4. The refrigeration cycle apparatus according to claim 2,

the spring is detachably fixed on the valve core and the base body,

the spring constant required to set the evaporation temperature to the first range and the superheat degree to the second range is a first constant when the specific refrigerant is circulated in the refrigeration cycle device,

in the case where the zeotropic mixture refrigerant is circulated in the refrigeration cycle apparatus, the spring constant is a second constant,

the ratio of the difference between the first coefficient and the second coefficient to the first coefficient is-78% or more and-1% or less.

5. The refrigeration cycle apparatus according to claim 1,

the refrigeration cycle device further includes a refrigerant container connected between the first heat exchanger and the temperature expansion valve,

the range of the evaporation temperature and the range of the degree of superheat of the refrigerant drawn into the compressor, which are assumed in the refrigeration cycle device, are a first range and a second range,

in the case where the specific refrigerant is circulated in the refrigeration cycle device, the product required to set the evaporation temperature to the first range and set the degree of superheat to the second range is a first value,

when the non-azeotropic refrigerant mixture is circulated in the refrigeration cycle apparatus, the volume is a second value,

the ratio of the difference between the first value and the second value to the first value is-78% or more and-1% or less or 2% or more and 271% or less.

6. The refrigeration cycle apparatus according to claim 5, wherein,

the position of the substrate can be adjusted in the specific direction,

setting the evaporation temperature to the first range and the degree of superheat to the position of the base body required in the second range as a first position when the specific refrigerant is circulated in the refrigeration cycle device,

when the non-azeotropic mixture refrigerant is circulated in the refrigeration cycle apparatus, the position of the base is the second position,

the ratio of the difference between the second displacement amount of the second position from the reference position and the first displacement amount of the first position from the reference position to the first displacement amount is-78% or more and-1% or less or 2% or more and 271% or less.

7. The refrigeration cycle apparatus according to claim 5, wherein,

the spring is detachably fixed on the valve core and the base body,

the spring constant required to set the evaporation temperature to the first range and the superheat degree to the second range is a first constant when the specific refrigerant is circulated in the refrigeration cycle device,

in the case where the zeotropic mixture refrigerant is circulated in the refrigeration cycle apparatus, the spring constant is a second constant,

the ratio of the difference between the first coefficient and the second coefficient to the first coefficient is-78% or more and-1% or less or 2% or more and 271% or less.

8. The refrigeration cycle device according to any one of claims 1 to 7, wherein,

the zeotropic mixed refrigerant is R463A,

the specific refrigerant is R410A.

Technical Field

The present invention relates to a refrigeration cycle apparatus including a temperature type expansion valve.

Background

A refrigeration cycle apparatus including a temperature type expansion valve has been known. For example, japanese patent application laid-open No. 2013-32875 (patent document 1) discloses a refrigeration cycle device including a temperature type expansion valve. In this refrigeration cycle device, R410A, which is a near azeotropic refrigerant mixture, circulates, and R410A or R125 is sealed in a temperature-sensitive cylinder together with a non-condensable gas. According to this refrigeration cycle apparatus, since the refrigerant mixed with the non-condensable gas is sealed in the temperature sensing tube, even when the temperature of the main body of the temperature type expansion valve decreases with respect to the temperature of the temperature sensing tube, the opening degree of the temperature type expansion valve easily follows the temperature of the temperature sensing tube. As a result, the degree of superheat is less affected by the temperature of the main body of the temperature expansion valve, and the degree of superheat deviation can be made constant.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-32875

Disclosure of Invention

Problems to be solved by the invention

In recent years, from the viewpoint of preventing Global Warming, as a refrigerant used in a refrigeration cycle apparatus, a non-azeotropic refrigerant having a lower Global Warming Potential (GWP) may be preferred instead of a near-azeotropic refrigerant or a single-component refrigerant (single refrigerant). In a non-azeotropic mixed refrigerant, a temperature gradient is generated between the temperature of a saturated liquid and the temperature of a saturated vapor at a constant pressure. Therefore, in a refrigeration cycle apparatus using a near-azeotropic refrigerant mixture or a single refrigerant, it is necessary to change the setting of the temperature expansion valve in order to achieve a desired operating state using a non-azeotropic refrigerant mixture. However, in the refrigeration cycle apparatus disclosed in patent document 1, the setting of the temperature expansion valve that matches the characteristics of the zeotropic refrigerant mixture is not taken into consideration.

The present invention has been made to solve the above-described problems, and an object thereof is to realize a desired operation state using a non-azeotropic refrigerant mixture in a refrigeration cycle apparatus capable of using a near-azeotropic refrigerant mixture or a single refrigerant.

Means for solving the problems

In the refrigeration cycle apparatus of the present invention, a non-azeotropic refrigerant mixture and a specific refrigerant can be used. The refrigeration cycle device is provided with a compressor, a first heat exchanger, a temperature-type expansion valve, a second heat exchanger, and a temperature-sensing tube. A specific refrigerant is sealed in the temperature sensing cylinder. The non-azeotropic mixture refrigerant or the specific refrigerant circulates in this order of the compressor, the first heat exchanger, the temperature expansion valve, and the second heat exchanger. The particular refrigerant is a single refrigerant or a near-azeotropic refrigerant mixture. The temperature sensing cylinder is configured to receive heat from refrigerant drawn into the compressor. The thermal expansion valve includes a frame, a spacer, a base, a valve element, and a spring. The spacer divides the frame into a first space and a second space and is movable in a specific direction. The spool is movable integrally with the spacer in a specific direction with respect to the base. The spring has a first end and a second end and is retractable in a specific direction. The first end is fixed to the valve core. The second end is fixed to the base. The temperature sensing cylinder is communicated with the first space. A flow path between the second heat exchanger and the compressor communicates with the second space. The thermal expansion valve is configured to be capable of adjusting the product of the displacement amount of the base from the reference position in the specific direction and the spring constant of the spring.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the refrigeration cycle apparatus of the present invention, the temperature expansion valve is configured to be able to adjust the product of the displacement amount of the base from the reference position in the specific direction and the spring coefficient of the spring, and therefore, the setting of the temperature expansion valve can be changed in accordance with the characteristics of the zeotropic refrigerant mixture. As a result, in the refrigeration cycle apparatus capable of using the near-azeotropic mixed refrigerant or the single refrigerant, a desired operation state can be achieved using the non-azeotropic mixed refrigerant.

Drawings

Fig. 1 is a functional block diagram showing the configuration of a refrigeration cycle apparatus according to embodiment 1.

Fig. 2 is a sectional view schematically showing the structure of the temperature type expansion valve of fig. 1.

Fig. 3 is a mollier plot showing the relationship of pressure, enthalpy and temperature for R410A and R463A.

Fig. 4 is a diagram showing a relationship between a degree of superheat of refrigerant sucked into the compressor and a proportion of a displacement amount of the adjustment screw.

Fig. 5 is a sectional view schematically showing the structure of the temperature type expansion valve according to modification 1 of embodiment 1.

Fig. 6 is a sectional view schematically showing the structure of a temperature type expansion valve according to modification 2 of embodiment 1.

Fig. 7 is a functional block diagram showing the configuration of the refrigeration cycle apparatus according to embodiment 2.

Fig. 8 is a diagram showing the relationship between the cycle composition ratio and the ratio of the amount of gas refrigerant in the accumulator to the amount of R463A (initial refrigerant amount) sealed in the refrigeration cycle apparatus when R463A is used as a zeotropic refrigerant mixture.

Fig. 9 is a diagram showing a relationship between a degree of superheat of the refrigerant sucked into the compressor and a ratio of the displacement amount of the adjustment screw 35.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding portions in the drawings are given the same reference numerals, and description thereof will not be repeated in principle.

Embodiment 1.

Fig. 1 is a functional block diagram showing the configuration of a refrigeration cycle apparatus 100 according to embodiment 1. As shown in fig. 1, the refrigeration cycle apparatus 100 includes a compressor 1, a condenser 2, a temperature expansion valve 3, an evaporator 4, a temperature sensing tube 5, and a controller 10. In the refrigeration cycle apparatus 100, the refrigerant circulates through the compressor 1, the condenser 2, the temperature expansion valve 3, and the evaporator 4 in this order.

A near-azeotropic refrigerant mixture or a single refrigerant is sealed in the temperature sensing cylinder 5. The temperature sensing cylinder 5 is configured to receive heat from refrigerant drawn into the compressor 1. The refrigerant sealed in the temperature sensing cylinder 5 is in a gas-liquid two-phase state due to the heat.

The control device 10 controls the amount of refrigerant discharged per unit time by the compressor 1 by controlling the driving frequency fc of the compressor 1. The control device 10 includes a storage unit 11. The storage unit 11 stores in advance a physical property value of the non-azeotropic refrigerant mixture, a physical property value of the refrigerant sealed in the temperature sensing cylinder 5, and a control target value of a specific parameter (for example, an evaporation temperature or a condensation temperature). In the non-azeotropic refrigerant mixture, the evaporation temperature at a certain pressure is the average temperature of the temperature at the point corresponding to the pressure on the saturated liquid line and the temperature at the point corresponding to the pressure on the saturated vapor line on the mollier diagram.

Fig. 2 is a sectional view schematically showing the structure of the thermal expansion valve 3 of fig. 1. As shown in fig. 2, the thermal expansion valve 3 includes a frame 30, a spacer 31, a shaft 32, a valve body 33, a spring 34, and an adjustment screw (base) 35.

The spacer 31 divides the housing 30 into a space S1 (first space) and a space S2 (second space), and is movable in the Z-axis direction (specific direction). The shaft body 32 extends in the Z-axis direction, and connects the spacer 31 and the valve body 33. The spacer 31, the shaft body 32, and the valve body 33 are integrally movable with respect to the adjustment screw 35. One end of the spring 34 is fixed to the valve body 33, and the other end of the spring 34 is fixed to the adjustment screw 35. The displacement amount s1 is the displacement amount of the spring 34. The position Z1 is a position in the Z axis direction of the other end. The position Z0 (reference position) is a position of the bottom of the space S3 through which the refrigerant from the condenser 2 passes. The displacement amount s0 is the displacement amount of the position Z1 from the position Z0. The temperature sensing cylinder 5 communicates with the space S1. The flow path FP between the evaporator 4 and the compressor 1 communicates with the space S2.

When the pressure (evaporation pressure) and the temperature of the refrigerant sucked into the compressor 1 are P1 and T1, respectively, the temperature of the refrigerant sealed in the temperature sensing tube 5 becomes T1. The pressure P2 of the refrigerant sealed in the temperature sensing tube 5 is expressed by the following formula (1) using the type of the refrigerant (refrigerant type) and the temperature T1.

P2 ═ f1 (type of refrigerant, T1) … (1)

The refrigerant sealed in the temperature sensing tube 5 exists in the space S1. When the area of the spacer 31 is a1, the force F2 exerted on the spacer 31 by the refrigerant is expressed by the following equation (2).

F2＝P2·A1…(2)

The refrigerant sucked into the compressor 1 exists in the space S2. The force F1 applied to the spacer 31 by the refrigerant is expressed by the following equation (3).

F1＝P1·A1…(3)

When the spring coefficient of the spring 34 is k1, the force F3 applied by the spring 34 to the valve body 33 is expressed by the following equation (4).

F3＝k1·(s0+s1)…(4)

The position of the valve element 33 is determined by the balance of forces expressed by the following equation (5).

F2＝F1+F3…(5)

By substituting formulae (1) to (4) for formula (5), formula (6) below can be obtained.

P2·A1＝P1·A1+k1·(s0+s1)…(6)

By modifying expression (6), expression (7) below can be obtained.

s0+s1＝(P2-P1)·A1/k1…(7)

By substituting formula (1) for formula (7), formula (8) below can be obtained.

s0+ s1 ═ (f1 (refrigerant type, T1) -P1) · a1/k1 … (8)

The value of the flow coefficient Cv having a correlation with the opening degree of the thermal expansion valve 3 is expressed by the following equation (9).

Cv∝1/(s0+s1)…(9)

As the refrigerant used in the refrigeration cycle apparatus 100, from the viewpoint of preventing Global Warming, a non-azeotropic refrigerant having a lower Global Warming Potential (GWP) may be preferable instead of the near-azeotropic refrigerant or the single refrigerant. For example, the following are known: since the operating pressure of R463A (GWP of 1494) as a non-azeotropic refrigerant mixture is similar to the operating pressure of R410A (GWP of 2090) as a near-azeotropic refrigerant mixture, R463A has an alternative to R410A.

Fig. 3 is a mollier plot showing the relationship of pressure, enthalpy and temperature for R410A and R463A. In fig. 3, the solid line shows the case of R410A, and the broken line shows the case of R463A. As shown in fig. 3, in the mollier plot of R463A, in the region of the gas-liquid two-phase state (the region between the saturated liquid line and the saturated vapor line), the isotherm has a negative slope and approaches the axis of enthalpy (horizontal axis) with an increase in enthalpy. Since the isotherm has a negative slope in the gas-liquid two-phase region, when the enthalpy is changed while the pressure is kept constant in the gas-liquid two-phase region, a temperature gradient occurs in which the temperature of R463A changes. On the other hand, in the case of R410A, a temperature gradient is not substantially generated in the gas-liquid two-phase state region. Therefore, when R463A is used instead of R410A, the setting of the temperature type expansion valve 3 needs to be changed in accordance with the setting of R410A in order to achieve a desired operating state that can be achieved using R410A.

Therefore, in the refrigeration cycle apparatus 100, the position of the adjustment screw 35 can be adjusted in the Z-axis direction. By appropriately changing the displacement amount s0 between the case of using a non-azeotropic refrigerant mixture and the case of using a near-azeotropic refrigerant mixture or a single refrigerant, a desired operating state can be achieved even when any refrigerant is used. Specifically, the displacement amount s0 can be set as follows: the opening degree of the thermal expansion valve 3 in the case of using R410A is the same as the opening degree of the thermal expansion valve 3 in the case of using R463A at a certain evaporation temperature and a certain superheat degree. Preferably, a scale for confirming the displacement amount s0 is added to the thermal expansion valve 3.

Fig. 4 is a diagram showing a relationship between a degree of superheat of the refrigerant sucked into the compressor 1 and a proportion of the displacement amount of the adjustment screw 35. The displacement amount ratio of the adjustment screw 35 is a ratio of a difference between the displacement amount s0 (first displacement amount) in the case of using R410A and the displacement amount s0 (second displacement amount) in the case of using R463A with respect to the first displacement amount. The range of the evaporation temperature assumed in the refrigeration cycle apparatus 100 is-40 ℃ to 10 ℃ (first range), and the range of the degree of superheat is 60 ℃ or less (second range). In FIG. 4, the curves C1 to C6 show the cases where the evaporation temperatures are-40 ℃, -30 ℃, -20 ℃, -10 ℃, 0 ℃, and 10 ℃, respectively.

As shown in fig. 4, the range of the displacement ratio of the adjustment screw 35 is-78% or more and-1% or less. By setting the range of the displacement amount ratio of the adjustment screw 35 to-78% or more and-1% or less, the degree of superheat and the evaporation temperature assumed in the refrigeration cycle device 100 can be achieved by either of R463A and R410A. Further, since it is not necessary to design a refrigeration cycle device of a different specification from the refrigeration cycle device 100 in order to use R463A, the manufacturing cost of the refrigeration cycle device capable of using R463A can be suppressed.

A modification of embodiment 1.

The formula (4) is developed as the following formula (9).

F3＝k1·s0+k1·s1…(1)

Setting the spring constant k1 and setting the range of the displacement amount ratio of the adjustment screw 35 to-78% or more and-1% or less means: regarding the value of the first term k1 · s0 of the formula (9), the range of the ratio of the difference between the value of the first term k1 · s0 (first value) in the case of using R410A and the value of the first term k1 · s0 (second value) in the case of using R463A to the first value (the ratio of the product of the spring coefficient and the displacement amount) is set to be-78% or more and-1% or less. The effect of the refrigeration cycle apparatus according to embodiment 1 can be achieved by setting the ratio of the product of the spring constant and the displacement amount to-78% or more and-1% or less.

Hereinafter, a case where the spring constant k1 is changed in modification 1 of embodiment 1 will be described. In modification 2 of embodiment 1, a case where both the spring constant k1 and the displacement amount s0 are changed will be described.

Modification 1 of embodiment 1.

Fig. 5 is a sectional view schematically showing the structure of the thermal expansion valve 3A according to modification 1 of embodiment 1. In the structure of the thermal expansion valve 3A, the adjusting screw 35 of the thermal expansion valve 3 in fig. 2 is replaced with a base 35A, and the spring is detachably fixed to the valve body 33 and the base 35A. Otherwise, the same description will not be repeated.

The base 35A is fixed to the bottom of the space S3 and cannot move in the Z-axis direction. That is, the displacement amount s0 cannot be adjusted in the thermal expansion valve 3A. In the temperature type expansion valve 3A, the spring 34A is used when R410A is used, and the spring 34B is used when R463A is used. The spring constant of the spring 34A is k11 (first spring constant), and the spring constant of the spring 34B is k12 (second spring constant).

The ratio of the difference between the spring constant k11 and the spring constant k12 to the spring constant k11 (the ratio of the difference in spring constant) is in the range of-78% to-1%. The same effect as in embodiment 1 can also be achieved by setting the ratio of the difference in spring constant to-78% or more and-1% or less.

It is preferable that the main bodies of the springs 34A and 34B or the bundle of the springs 34A and 34B have a description of which type of refrigerant spring is known, such as "R410A" and "R463A". In the specification of the refrigeration cycle apparatus, it is preferable that the type of spring suitable for the type of refrigerant usable in the refrigeration cycle apparatus is described in terms of the type of refrigerant.

Modification 2 of embodiment 1.

Fig. 6 is a sectional view schematically showing the structure of a thermal expansion valve 3B according to modification 2 of embodiment 1. The thermal expansion valve 3B is different from the thermal expansion valve 3A in that a spring 34C is detachably fixed to a valve body 33 and an adjustment screw 35 in fig. 2. Otherwise, the same description will not be repeated.

In the temperature-type expansion valve 3B, the spring 34C is used in the case of using R410A, and the displacement amount s0 is adjusted to s21 (first displacement amount). The spring 34D is used in the case of using R463A, and the displacement amount s0 is adjusted to s22 (second displacement amount). The spring constant of the spring 34C is k21 (first spring constant), and the spring constant of the spring 34D is k22 (second spring constant).

The ratio of the difference between the value of the product k21 · s21 (first value) and the value of the product k22 · s22 (second value) to the first value is in the range of-78% to-1%. The same effect as in embodiment 1 can also be achieved by setting the ratio of the product of the spring constant and the displacement amount to-78% or more and-1% or less.

As described above, according to the refrigeration cycle apparatus of embodiment 1 and modifications 1 and 2, a desired operation state can be achieved using a non-azeotropic refrigerant mixture.

Embodiment 2.

In embodiment 1, a case where the composition ratio of the zeotropic refrigerant mixture circulating through the refrigeration cycle apparatus (cycle composition ratio) is not substantially changed is described. In embodiment 2, a case where the cycle composition ratio of the zeotropic refrigerant mixture circulating through the refrigeration cycle apparatus changes will be described.

Fig. 7 is a functional block diagram showing the configuration of the refrigeration cycle device 200 according to embodiment 2. The refrigeration cycle apparatus 200 is configured by adding an accumulator (receiver)6 (refrigerant container) to the configuration of the refrigeration cycle apparatus 100 in fig. 1. Otherwise, the same description will not be repeated.

The liquid zeotropic refrigerant mixture is accumulated in the accumulator 6, and the refrigerant having a lower boiling point than other refrigerants (low boiling point refrigerant) in the refrigerant included in the zeotropic refrigerant mixture is vaporized. As the zeotropic refrigerant mixture circulates through the refrigeration cycle apparatus 200, the amount of the refrigerant (gas refrigerant) contained in the accumulator 6 increases. Since the amount of the low boiling point refrigerant contained in the zeotropic refrigerant mixture circulating through the refrigeration cycle apparatus 200 decreases, the cycle composition ratio of the zeotropic refrigerant mixture circulating through the refrigeration cycle apparatus 200 changes.

Fig. 8 is a diagram showing a relationship between a ratio of the amount of the gas refrigerant in the accumulator 6 to the amount of R463A (initial refrigerant amount) sealed in the refrigeration cycle device 200 when R463A is used as a zeotropic refrigerant mixture, and a cycle composition ratio.

R463A is substituted with 36: 30: 14: 14: the weight percent (wt%) (pure composition ratio) of 6 comprised R32, R125, R1234yf, R134a and CO 2. To ensure refrigerant pressure, CO2 is contained in R463A. The boiling points at 1 atmosphere of R32, R125, R1234yf, R134a and CO2 are-51.7 ℃, -48.1 ℃, -29.4 ℃, -26.1 ℃ and-78.5 ℃ respectively. Among the refrigerants contained in R463A, the boiling point of CO2 is the lowest, and the boiling point of R32 is lower than that of CO 2. The low boiling point refrigerant of R463A contains R32 and CO 2.

As shown in fig. 8, when the amount of the gaseous refrigerant in the accumulator 6 is 0, the cycle composition ratio of R32, R125, R1234yf, R134a, and CO2 is equal to the composition ratio (initial value) of R463A. The cycle composition ratio of CO2 and R32 decreases with an increase in the amount of gaseous refrigerant in the accumulator 6. On the other hand, the cyclic composition ratios of R125, R1234yf, and R134a increased.

Referring to fig. 7 and 2, when the cycle composition ratio of CO2, which is a low-boiling-point refrigerant, decreases, the evaporation temperature of the refrigerant circulating in the refrigeration cycle apparatus 200 increases relative to the evaporation temperature of R463A with a constant pressure. In order to maintain the evaporation temperature, the evaporation pressure P1 needs to be lowered. When the evaporation pressure P1 falls, the force F2 becomes small, and therefore the opening degree of the thermal expansion valve 3 becomes large. By reducing the displacement amount s0, the opening degree of the thermal expansion valve 3 can be maintained with respect to a decrease in the cycle composition ratio of CO 2.

Fig. 9 is a diagram showing a relationship between the degree of superheat of the refrigerant sucked into the compressor 1 and the displacement amount ratio of the adjustment screw 35. The range of the evaporation temperature assumed in the refrigeration cycle apparatus 200 is-40 ℃ or higher and 10 ℃ or lower (first range), and the range of the degree of superheat is 60 ℃ or lower (second range). In FIG. 9, the curves C21 to C26 show the cases where the evaporation temperatures are-40 ℃, -30 ℃, -20 ℃, -10 ℃, 0 ℃, and 10 ℃, respectively.

The cyclic composition ratio of R463A in fig. 9 is a cyclic composition ratio surrounded by the broken line Cr in fig. 8. The reason why R463A having this cyclic composition ratio is selected as a comparison target with R410A is: the cycle composition ratio enclosed by the broken line Cr is the cycle composition ratio closest to the critical state where no liquid refrigerant is present in the accumulator 6 (the ratio of the amount of gas refrigerant in the accumulator 6 to the initial amount of refrigerant becomes 1) among the cycle composition ratios shown in fig. 9.

As shown in fig. 9, the range of the displacement ratio of the adjustment screw 35 is 2% or more and 271% or less. By setting the range of the displacement amount ratio of the adjustment screw 35 to 2% or more and 271% or less, the degree of superheat and the evaporation temperature assumed in the refrigeration cycle device 200 can be achieved by either of R463A and R410A. Further, since it is not necessary to design a refrigeration cycle apparatus of a different specification from the refrigeration cycle apparatus 200 in consideration of the change in the cycle composition ratio of R463A, the manufacturing cost of the refrigeration cycle apparatus capable of using R463A can be suppressed. Further, by setting the range of the displacement amount ratio of the adjustment screw 35 to-78% or more and-1% or less while the cycle composition ratio of R463A is not changed, as in embodiment 1, the degree of superheat and the evaporation temperature assumed in the refrigeration cycle apparatus 200 can be achieved by either of R463A and R410A.

Further, similarly to embodiment 1, the ratio of the difference in spring constant or the ratio of the product of the spring constant and the displacement amount may be set to-78% or more and-1% or less or 2% or more and 271% or less.

As described above, according to the refrigeration cycle apparatus of embodiment 2, even if the cycle composition ratio of the zeotropic refrigerant mixture changes, a desired operation state can be realized.

The embodiments and modifications disclosed herein are also intended to be appropriately combined and implemented in a range not inconsistent with the above description. The embodiments and modifications disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

Description of reference numerals

1 compressor, 2 condenser, 3A, 3B temperature expansion valve, 4 evaporator, 5 temperature-sensing cylinder, 6 reservoir, 10 control device, 11 storage part, 30 frame, 31 spacer, 32 axis, 33 valve core, 34A-34D spring, 35 adjusting screw, 35A base, 100, 200 refrigeration cycle device, FP flow path.