JPH08277389A - Mixed working fluid and heat pump device using the same - Google Patents

Abstract

PURPOSE: To obtain a mixed working fluid comprising trifluoroiodomethane and difluoromethane, etc., in a specific ratio, hardly having influence on an ozone layer of the stratosphere, having slight global waring action, capable of enlarging the width of a working fluid, useful as a heat pump, etc. CONSTITUTION: This mixed working fluid comprises (A) 35-80wt.% of trifuoroiodomethane and either or both of (B) <=40wt.% of a difluoromethane and (C) <=65wt.% of pentafluoroethane. The mixed working fluid is preferably obtained by mixing 25-50wt.% of an azeotropic mixture of 40-60wt.% of the component B and 60-40wt.% of the component C with 50-75wt.% of the component A.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a mixed working fluid containing trifluoroiodomethane and an air conditioner using the same.
The present invention relates to a heat pump device such as a refrigerator and a refrigerator.

[0002]

2. Description of the Related Art Conventionally, in heat pump devices such as air conditioners, refrigerators and refrigerators, compressors, condensers, throttle devices such as capillary tubes and expansion valves, and evaporators are connected by piping, and a working fluid is circulated therein. By doing so, a cooling action is performed. In these heat pump devices, halogenated hydrocarbons derived from methane or ethane called CFCs (hereinafter referred to as R ○○ or R ○○○) are known as working fluids, and the usage temperature is the condensation temperature. Is generally used at a temperature of about 50 ° C. and an evaporation temperature of about 0 ° C. Among them, chlorodifluoromethane (CHClF ₂ ,
R22, boiling point -40.8 ° C) was widely used as a working fluid for air conditioners, refrigerators, refrigerators, etc., but in recent years, the depletion of the stratospheric ozone layer due to CFCs has become a global environmental problem, and the stratospheric ozone depletion capacity is high. Therefore, the Montreal International Convention has already decided the regulation of the usage and production, and there is a movement to abolish the usage and production in the future. In order to have almost no effect on the stratospheric ozone layer, it is required that the molecular structure does not contain chlorine, and as a possible possibility, chlorine-free fluorohydrocarbons have been proposed. ing.

[0003]

However, the working fluid of fluorohydrocarbons has a global warming potential (hereinafter referred to as GW) which has an effect on global warming which is another environmental problem.
(Denoted as P) is said to have the same effect as R22. IPCC (Intergovermental Panel on 1994)
According to a report by Climate Change, an intergovernmental panel on climate change, when the GWP of carbon dioxide (CO ₂ ) is set to 1, the comparison value for 100 years on the horizontal axis at the time of accumulation is 170 for the GWP of R22.
0, among fluorohydrocarbons that do not contain chlorine, difluoromethane (CH ₂ F ₂ , R32, boiling point -52 ° C) has a GWP of 5
80, pentafluoroethane (CF ₃ -CHF _2, R125, boiling point -48 ° C.) is GWP of 3200,1,1,1- trifluoroethane (CF ₃ -CH _3, R143a, boiling point -48 ° C.)
GW of the GWP 4400,1,1,1,2- tetrafluoroethane _{(CF 3 -CH 2 F, R134a} , boiling point -27 ° C.)
P is 1300, 1,1-difluoroethane (CHF ₂ —CH ₃ ,
R152a, boiling point -25 ° C) has a GWP of 140. Here, R32, R125, and R143a have lower boiling points than R22, and the condensing pressure of the heat pump device becomes very high. Therefore, R32, R125, and R143a cannot be used alone as a substitute for R22.
Since R134a and R152a have a higher boiling point than R22 and the refrigerating capacity of the heat pump device is lowered, R134a and R152a cannot be replaced by R22 alone. Further R32, R1
43a and R152a have the drawback of being flammable.

The present invention has been tried in view of the above-mentioned problems, and has almost no effect on the stratospheric ozone layer, and may have a small effect on global warming.
The present invention provides an alternative working fluid of No. 2, and the present invention seeks to propose a mixed working fluid containing chlorine-free trifluoroiodomethane.

Here, trifluoroiodomethane (CF ₃ I,
(Boiling point −22.7 ° C.) is also known as iodotrifluoromethane or trifluoromethyliodide, and is composed of only 1 carbon atom, 3 fluorine atoms and 1 iodine atom, and does not contain chlorine in the molecular structure. Therefore, it has almost no ozone depletion capability and is nonflammable. The GWP of trifluoroiodomethane is much smaller than that of fluorohydrocarbons, and is being studied as an alternative that can be almost the same as carbon dioxide (CO ₂ ). However, trifluoroiodomethane has a boiling point at atmospheric pressure of −
Since it is 22.7 ° C., it is possible to form a mixture having a boiling point equivalent to that of R22 by mixing with difluoromethane (R32) or pentafluoroethane (R125) and specifying the composition range. Here, difluoromethane (R32) and pentafluoroethane (R1)
25) is Japanese Patent Publication No. 6-914 (USP 4,978,46).
Since it is known to form an azeotrope-like mixture in 7), the R32 / R125 mixture may be mixed with trifluoroiodomethane.

[0006]

In order to solve the above-mentioned problems, the present invention is a mixed working fluid composed of trifluoroiodomethane containing no chlorine and fluorohydrocarbons, wherein the fluorohydrocarbons are difluoromethane. (R32) and / or pentafluoroethane (R125). Furthermore, the present invention specifies the composition range of these mixtures such that the vapor pressure of the mixtures is approximately equal to R22. Further, the present invention is a heat pump device using the working fluid.

[0007]

The present invention, by the combination described above, makes the working fluid a mixture of trifluoroiodomethane and fluorohydrocarbons containing no chlorine so that the working fluid has almost no influence on the stratospheric ozone layer. It is possible. In particular, the ODP in the above-mentioned combination and in the specified composition range is also expected to be 0, which is a very promising working fluid as an alternative to R22.

Furthermore, such a mixture is considerably smaller than the GWP of fluorohydrocarbons, and almost no carbon dioxide (C
O ₂ ), which may be about the same as trifluoroiodomethane and difluoromethane (R 32) or pentafluoroethane (R 125), or both, so the vapor pressure of the mixture is almost equal to R 22. According to the composition range of difluoromethane (R32) and pentafluoroethane (R125) specified as follows, the influence on global warming can be reduced.

Further, since trifluoroiodomethane is nonflammable, not only the mixture with R125 is nonflammable, but the composition range of R32 is further limited to the nonflammable range, so that it can be used as it is in a normal heat pump device. It can be used.

The present invention also provides R, which has a lower boiling point than R22.
32, R125, and trifluoroiodomethane, which has a higher boiling point than R22, are mixed and the composition range thereof is specified, so that the temperature of the heat pump device such as an air conditioner, a refrigerator, and a refrigerator is about 0 to about 50 ° C. , R22
It is possible to provide a working fluid that has a vapor pressure similar to that of R22 and can be expected to have a refrigerating capacity equivalent to that of R22, and that can be used in existing equipment using R22.

The mixture has a boiling point difference of about 25 de
Since it is a mixture of difluoromethane (R32), pentafluoroethane (R125), and trifluoroiodomethane within g, it is expected to be a near-azeotropic non-azeotropic mixture, and a small temperature gradient is generated in the condensation process and the evaporation process. Therefore, by constructing a Lorentz cycle in which the temperature difference with a heat source fluid such as air is made close, a heat pump device having a coefficient of performance (COP) higher than that of R22 can be constructed.

[0012]

The working fluid of the present invention contains trifluoroiodomethane and / or difluoromethane (R32) and pentafluoroethane (R125). The composition range of these mixtures is such that the vapor pressure of the mixture is almost R.
It is specified to be equivalent to 22. Examples of working fluids according to the present invention will be described below with reference to vapor pressure diagrams.

FIG. 1 shows difluoromethane (CH ₂ F ₂ , R3
2, boiling point -52 ° C.), pentafluoroethane (CF ₃ -CH
F _2, R125, boiling point -48 ° C.), trifluoroiodomethane (CF ₃ I, the three types constituted the working fluid by a mixture of the boiling point -22.7 ℃), triangular coordinates an equilibrium state at a constant temperature and constant pressure It is shown by using.

In the present triangular coordinates, a single substance is arranged at each vertex of the triangle counterclockwise from the upper vertex in the ascending order of the boiling points, and the composition ratio of each component at a certain point on the coordinate plane ( The weight ratio) is represented by the ratio of the distance between the point and each side of the triangle. At this time, the distance between the point and the side of the triangle corresponds to the composition ratio of the substance described at the vertex of the triangular coordinates on the side opposite to the side.

In FIG. 1, 1 indicates a temperature of 0 ° C. and a pressure of 0.4.
It is a vapor-liquid equilibrium line of the mixture at 98 MPa, and this temperature / pressure corresponds to the saturated state of R22 at a temperature of 0 ° C. Line 1V above the vapor-liquid equilibrium line (equivalent to R220 ° C) 1
Represents a saturated vapor phase line, and a line 1L below the vapor-liquid equilibrium line (corresponding to R220 of 0 ° C.) 1 represents a saturated liquidus line, and a vapor-liquid equilibrium state is established in a range sandwiched by these lines. 2 is temperature 5
This is a vapor-liquid equilibrium line of the mixture at 0 ° C. and a pressure of 1.943 MPa, and this temperature / pressure also corresponds to the saturated state of R22 at a temperature of 50 ° C.

The composition on the saturated vapor phase line V vaporizes at a pressure higher than that of R22 at the same temperature as R22 and liquefies at the same pressure as R22. The composition on the saturated liquidus line L is vaporized at the same temperature as R22 at the same pressure as R22 and liquefied at a pressure lower than R22. The composition in the area between these two lines vaporizes at a pressure higher than R22 and liquefies at a pressure lower than R22 at the same temperature as R22. That is, the composition in the area between the vapor-liquid equilibrium lines 2 at 50 ° C. is 5
At 0 ° C, the gas phase changes to a liquid phase at a pressure lower than R22, and at the same pressure as R22, a gas phase higher than 50 ° C condenses and changes to a liquid phase lower than 50 ° C. The composition in the area between the vapor-liquid equilibrium line 1 at 0 ° C changes from the liquid phase to the vapor phase at a pressure higher than R22 at 0 ° C, and the liquid phase lower than 0 ° C evaporates at the same pressure as R22. Then, the gas phase changes to a temperature higher than 0 ° C. That is, the composition between the gas-liquid parallel lines 1 and 2 has almost the same evaporation pressure as that of R22 at a temperature of 0 ° C. and has the same condensation pressure as that of R22 at a temperature of 50 ° C. And so on.

As can be seen from the figure, the composition range in which R32, R125 and trifluoroiodomethane are 0 to about 40% by weight, 0 to about 65% by weight and about 35 to about 80% by weight, respectively, is about 0. ~ R at a usage temperature of about 50 ° C
It is desirable because it has a vapor pressure almost equal to 22. Furthermore, R32, R125, and trifluoroiodomethane are 0 to about 35% by weight, 0 to about 60% by weight, and about 40%, respectively.
The composition range of about 80% by weight is 0 ° C and 50 ° C.
It is particularly desirable because it has a vapor pressure almost equal to R22 at all utilization temperatures between.

The composition of the working fluid at points A ₁ to F ₁ in FIG. 1 is shown in (Table 1).

[0019]

[Table 1]

Points A ₁ to C ₁ are gas-liquid equilibrium lines (R2250
(Equivalent to ° C) 2 on the saturated vapor line 2V, and the saturated liquidus line 1V of the vapor-liquid equilibrium line (R22 0 ° C equivalent) 1 and the saturated liquidus line 1L of the vapor-liquid equilibrium line (R22 0 ° C equivalent) The temperature is 0 ° C and the pressure is 0.49 because it is in the range between both lines.
At 8 MPa (corresponding to the saturated state of R22), a gas-liquid equilibrium state is reached, and the temperature is 50 ° C. and the pressure is 1.943 MPa (R
(Corresponding to the saturated state of 22), a saturated vapor phase equilibrium state is reached. Further, points D ₁ to F ₁ are gas-liquid equilibrium lines (R2250
℃ 2) saturated liquidus line 2L, gas-liquid equilibrium line (R22 0 ° C equivalent) 1 saturated gas phase line 1V and gas-liquid equilibrium line (R220 0 ° C equivalent) 1 saturated liquidus line 1L The temperature is 0 ° C and the pressure is 0.49 because it is in the range between both lines.
At 8 MPa (corresponding to the saturated state of R22), a gas-liquid equilibrium state is reached, and the temperature is 50 ° C. and the pressure is 1.943 MPa (R
(Corresponding to the saturated state of No. 22), it becomes a saturated liquid phase state. Therefore, the working fluid having the composition shown in (Table 1) achieves a saturated state or a gas-liquid equilibrium state under the conditions of the saturated vapor pressure of R22 at 0 ° C and 50 ° C, and the working fluid has a temperature of approximately 0 to approximately 5.
By operating at a saturated vapor pressure of R22 at the same temperature at a use temperature of 0 ° C., it becomes possible to obtain a condensation temperature / evaporation temperature almost equal to that of R22.

Here, only the points on the gas-liquid equilibrium line (corresponding to R220 ° C.) 1 or the gas-liquid equilibrium line (corresponding to R2250 ° C.) 2 are described, but points inside the points A ₁ to F ₁ That is, the same operation is performed on the working fluid having a composition in a gas-liquid equilibrium state at a temperature of 0 ° C. and a pressure of 0.498 MPa and at a temperature of 50 ° C. and a pressure of 1.943 MPa (both correspond to the saturated state of R22). Almost 0
It is possible to obtain a condensation temperature / evaporation temperature almost equal to R22 at a use temperature of about 50 ° C.

For example, 50% by weight, which is an azeotropic mixture,
When 50 wt% R32 / R125 mixture is mixed with trifluoroiodomethane, it is shown on the dashed line in FIG. In this case, the R32 / R125 mixture and trifluoroiodomethane are each about 25 to about 50% by weight,
The composition range is about 50 to about 75% by weight, that is, R32, R125 and trifluoroiodomethane are about 12.5 to about 25% by weight, and about 12.5 to about 2 respectively.
The composition range of 5% by weight, about 50 to about 75% by weight, is desirable because it has a vapor pressure almost equal to that of R22 at a use temperature of about 0 to about 50 ° C. The GWP of the R32 / R125 mixture (50 wt% / 50 wt%) is 1900.
Therefore, the working fluid mixed with trifluoroiodomethane which has almost negligible GWP is R3
About 25 to about 50% by weight of the composition range of the 2 / R125 mixture
The GWP can be reduced to 500 to 950 which is equivalent to, and the influence on global warming can be made smaller than that of R22. The R32 / R125 mixture, which is an azeotrope-like mixture, contains 40 to 60% by weight of R32 and 60 to 40 of R125.
The GWP of the mixed working fluid, in which the content is preferably wt% and mixed with trifluoroiodomethane, can similarly reduce the influence on global warming.

(Table 2) shows 50% by weight / 50% by weight of R
It is the ideal refrigeration performance of a ternary system consisting of a 32 / R125 mixture and trifluoroiodomethane. The conditions are the case where the condensation average temperature is 50 ° C., the evaporation average temperature is 0 ° C., the condenser outlet supercooling degree is 0 deg, and the evaporator outlet superheat degree is 0 deg. As can be seen from (Table 2), R32 / R125 (5 which is the composition range for making the vapor pressure equivalent to that of R22
0 to 50% by weight) and 50 to 75% by weight of trifluoroiodomethane, that is, R32 is 12.5 to 25% by weight and R125 is 125% by weight.
12.5 to 25% by weight and trifluoroiodomethane 50 to 75% by weight, the three-component system is almost R22.
Shows the same characteristics as. 20% by weight of R32, R12
The three-component system in which 5 is 20% by weight and trifluoroiodomethane is 60% by weight exhibits almost the same characteristics as R22 in both refrigerating capacity and coefficient of performance. In addition, the temperature gradient in the condensation process and the evaporation process is 10 deg or less, and a near azeotropic mixture is formed. By utilizing this temperature gradient in reverse to construct a Lorentz cycle in which the temperature difference with the heat source fluid is close to each other, a higher coefficient of performance can be expected than in (Table 1).

[0024]

[Table 2]

Further, in the case of a mixed working fluid of two kinds consisting only of trifluoroiodomethane and difluoromethane (R32), the composition range for making the vapor pressure equivalent to that of R22 is the trifluoride trigonometric coordinates in FIG. Odomethane and R3
The range on the side connecting the two is suitable. In this case, trifluoroiodomethane and R32 are about 60 to about 8 respectively.
The composition range is preferably 0% by weight, approximately 20 to approximately 40% by weight, and the flammability of R32 can be mitigated by the incombustibility of trifluoromethane. R32 alone GWP is 5
The working fluid, which is smaller than 80 and R22, and mixed with trifluoroiodomethane, which has almost negligible GWP, can reduce the GWP to 120 to 230 corresponding to about 20 to about 40 wt% of the composition range of R32. The effect on global warming can be made much smaller than that of R22. Therefore, the binary system consisting only of trifluoroiodomethane and difluoromethane (R32) is
It is useful as a substitute for No. 22.

Table 3 shows the ideal refrigerating performance of a binary system consisting only of R32 and trifluoroiodomethane. The conditions are that the condensation average temperature is 50 ° C and the evaporation average temperature is 0.
C., the supercooling degree at the condenser outlet is 0 deg, and the superheat degree at the evaporator outlet is 0 deg. As can be seen from (Table 3),
Trifluoroiodomethane, which is a composition range for making the vapor pressure equivalent to that of R22, 60 to 80% by weight, and difluoromethane (R32) is 20 to 40% by weight.
The component system exhibits almost the same characteristics as R22. Especially, the two-component system consisting of 70% by weight of trifluoroiodomethane and 30% by weight of difluoromethane (R32) is
Both freezing capacity and coefficient of performance are improved over R22. In addition, the temperature gradient in the condensation process and the evaporation process is 10 deg or less, and a near azeotropic mixture is formed. By utilizing this temperature gradient in reverse to construct a Lorentz cycle in which the temperature difference with the heat source fluid is close, a higher coefficient of performance can be expected than in (Table 3).

[0027]

[Table 3]

Further, in the case of a mixed working fluid of two kinds consisting only of trifluoroiodomethane and pentafluoroethane (R125), the composition range for making the vapor pressure equivalent to that of R22 is the trifluoride of triangular coordinates in FIG. The range on the side connecting the loiodomethane and R125 is preferable. In this case, it is desirable that the composition range is such that trifluoroiodomethane and R125 are approximately 35 to approximately 60% by weight and approximately 40 to approximately 65% by weight, respectively, and both are nonflammable.
The binary mixture is also nonflammable. R125 alone GWP
Is larger than R22, but the working fluid mixed with trifluoroiodomethane, which has almost negligible GWP, is about 40 to about 6 in the composition range of R125.
The GWP can be reduced to 1300 to 2100, which corresponds to 5% by weight, and the composition range of R125 is about 40 to about 53% by weight.
If it is limited to, it is possible to reduce the GWP to 1300 to 1700, which is smaller than R22 and has an influence on global warming. Therefore, a binary system consisting only of trifluoroiodomethane and pentafluoroethane (R125) is also a useful alternative to R22.

Table 4 shows the ideal refrigeration performance of a binary system consisting of R125 and trifluoroiodomethane only. The conditions are that the condensation average temperature is 50 ° C and the evaporation average temperature is 0.
C., the supercooling degree at the condenser outlet is 0 deg, and the superheat degree at the evaporator outlet is 0 deg. As can be seen from (Table 4),
A two-component system consisting of 35 to 60% by weight of trifluoroiodomethane and 40 to 65% by weight of pentafluoroethane (R125), which is a composition range for obtaining a vapor pressure equivalent to that of R22, is inferior to R22. Although exhibiting characteristics, it has an effect of reducing the discharge temperature. In addition, the temperature gradient in the condensation process and the evaporation process is 10 deg or less, and a near azeotropic mixture is formed. By utilizing this temperature gradient in reverse to construct a Lorentz cycle in which the temperature difference with the heat source fluid is close, a higher coefficient of performance can be expected than in (Table 4).

[0030]

[Table 4]

[0031]

As is apparent from the above description, the present invention comprises 35 to 80% by weight of trifluoroiodomethane,
40% by weight or less of difluoromethane (R32) and 6
By including 5 wt% or less of either or both of pentafluoroethane (R125), the working fluid as a mixture consisting only of compounds having no chlorine in the molecular structure, and by specifying its composition range, (1 ) The effect on the stratospheric ozone layer is the same as R22.
It is possible to expand the range of choices of working fluid that are almost eliminated. (2) Since such a mixture is composed of trifluoroiodomethane (R32) and pentafluoroethane (R125), which have almost no negligible global warming potential, the effect of trifluoroiodomethane on global warming can be reduced. It can be reduced depending on the composition range. (3) Since trifluoroiodomethane is nonflammable,
The mixture with R125 is not only non-flammable but also R3
By further limiting the composition range of 2 to the non-flammable range, it can be used as it is in a normal heat pump device. (4) At the operating temperature of a heat pump device such as an air conditioner, a refrigerator, or a refrigerator, which is approximately 0 to approximately 50 ° C., has a vapor pressure similar to that of R22 and can be expected to have the same refrigerating capacity as R22. It can be used with existing equipment. (5) It is expected that such a mixture will be an almost azeotropic non-azeotropic mixture, and by constructing the Lorentz cycle, a higher coefficient of performance than that of R22 can be expected. And so on.

[Brief description of drawings]

FIG. 1 is a triangular coordinate diagram of an equilibrium state of a working fluid composed of a mixture of R32, R125 and trifluoroiodomethane at a constant temperature and a constant pressure.

[Explanation of symbols]

 1 Gas-liquid equilibrium line (R22 equivalent to 0 ° C) 2 Gas-liquid equilibrium line (R22 equivalent to 50 ° C) V Saturated vapor phase line L Saturated vapor phase line

Claims (6)

[Claims] 1. A mixed working fluid comprising 40% by weight or less of difluoromethane and 65% by weight or less of pentafluoroethane and 35-80% by weight of trifluoroiodomethane. 2. A three-component composition comprising 35-80 wt% trifluoroiodomethane, 40 wt% or less difluoromethane, and 65 wt% or less pentafluoroethane. Mixed working fluid. 3. An azeotrope-like mixture containing 40 to 60% by weight of difluoromethane and 60 to 40% by weight of pentafluoroethane is mixed with 25 to 50% by weight of trifluoroiodomethane. The mixed working fluid according to claim 2, wherein: 4. The mixed working fluid according to claim 1, which comprises two components of 60 to 80% by weight of trifluoroiodomethane and 20 to 40% by weight of difluoromethane. 5. Two parts of 35 to 60% by weight of trifluoroiodomethane and 40 to 65% by weight of pentafluoroethane.
The mixed working fluid of claim 1, wherein the mixed working fluid comprises components. 6. 35 to 80% by weight of trifluoroiodomethane and 40% by weight or less of difluoromethane and 65.
The heat pump apparatus using the mixed working fluid according to claim 1, which contains less than or equal to 1% by weight of pentafluoroethane.