JPH08151570A - Working fluid - Google Patents

Abstract

PURPOSE: To obtain a working fluid, comprising 1,1-difluoroethane and 1,1,1- trifluoroethane without destroying the stratospheric ozonosphere, excellent in refrigerant characteristics without causing the deterioration in the heat exchange efficiency or sticking of frost to an evaporator and useful for heating- cooling combination appliances, etc. CONSTITUTION: This working fluid comprises (A) 35-45wt.% 1,1-dlfluoroethane (R152a) and (B) 1,1,1-trifluoroethane or <=45wt.% component (A), (C) <=20wt.% isobutane (R600a) and the component (B) at compositional ratios of the components (A) to (C) within the range W1 , surrounded by point A (30, 20), point B (35, 20), point C (45, 10), point D (45, 0), point E (35, 0) and point F (30, 15) and indicated by solid lines in Figure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working fluid used in a heat pump device for heating and cooling operations, hot water supply and freezing, and having no danger of destroying the ozone layer.

[0002]

2. Description of the Related Art Freon, which has been widely used as a refrigerant in a heat pump apparatus used for indoor air conditioning (hereinafter, referred to as "specific freon"), is not flammable, explosive, or toxic, and is in a normal state. It has excellent usage characteristics such as not corroding metal parts.

However, specific CFCs which have been widely used as chemically extremely stable enter the stratosphere when released into the atmosphere and stay in the stratosphere for a very long time until they are decomposed by UV rays, and thus emit UV rays. Its use has been internationally restricted as it blocks and destroys the ozone layer, which protects living creatures, including humans, on the ground.

Therefore, chlorodifluoromethane (CHCl), which has a lower stratospheric ozone depletion capacity than specific fluorocarbons, has been recently used as an alternative refrigerant for the specific fluorocarbons used conventionally.
F ₂ , R22) is used.

[0005]

The R22 is trichlorofluoromethane (C
The ozone depletion coefficient (hereinafter referred to as ODP), which indicates the stratospheric ozone depletion ability when Cl ₃ F, R11) is set to 1, is extremely small at 0.05 and is not a specified CFC, but is widely used in refrigeration and air conditioning equipment. With its widespread use, it is expected that the amount of R22 used and produced will increase in the future, and the impact of R22 on the stratospheric ozone layer cannot be ignored.

Therefore, there is a demand for early development of a working fluid that is an alternative refrigerant for R22 and has little effect on the stratospheric ozone layer. The present invention has been made in view of the above circumstances, and provides a working fluid having a ODP of 0 and a refrigerant characteristic equal to or higher than that of R22.

[0007]

The working fluid of the first invention is 1,1-difluoroethane (CH ₃ CHF ₂ , R152).
a) 35 to 45% by weight, the balance is 1,1,1-trifluoroethane (CH ₃ CF ₃ , R143a), containing at least the above-mentioned two components.

The working fluid of the second invention comprises 45% by weight or less of 1,1-difluoroethane, isobutane ((CH ₃ ) ₃ CH,
R600a) 20% by weight or less, the balance is 1,1,1-trifluoroethane, and the component ratio of 1,1-difluoroethane and isobutane is point A (30,20) indicated by the solid line in the attached FIG.
Point B (35,20), Point C (45,10), Point D (45,0), Point E
It is a range surrounded by (35, 0) and a point F (30, 15) and contains at least the above-mentioned three kinds of components.

The working fluid of the third invention comprises 45% by weight or less of 1,1-difluoroethane, 25% by weight or less of octafluorocyclobutane (C ₄ F ₈ , RC318), and the balance is 1,1,1-
In the case of trifluoroethane, the component ratios of 1,1-difluoroethane and octafluorocyclobutane are points G (40, 25), H (45, 0), I (35,
0) and the point J (35, 20), and it contains at least the above-mentioned three kinds of components.

[0010]

According to the present invention, the working fluid has an ozone depletion coefficient of O
Comprised of two components, 1,1-difluoroethane and 1,1,1-trifluoroethane, having a DP of 0, or three components containing either isobutane or octafluorocyclobutane component in these two components Therefore, there is no risk of destroying the stratospheric ozone layer.

The working fluid has a refrigerant characteristic equal to or higher than that of R22, and is excellent as a substitute refrigerant for R22. Further, the temperature difference between the working fluid before and after passing through the evaporator or the condenser is small, and there is no fear that the heat exchange efficiency is reduced and frost is attached to the evaporator.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a heat pump device for testing a working fluid of the present invention, which includes a compressor 1, a condenser 2,
A working fluid is circulated in a refrigeration cycle formed by sequentially providing a pressure reducer 3 and an evaporator 4.

The flow of the working fluid in the refrigeration system will be described with reference to FIGS. 1 and 2. Here, FIG. 2 shows a Mollier diagram of the refrigeration cycle, in which the vertical axis represents pressure and the horizontal axis represents enthalpy. In the figure, x is a curve indicating the boundary between the vapor phase state, the liquid phase state and the gas-liquid two-phase state of the refrigerant, the curved portion on the right side of the vertex y indicates the saturated vapor line, and the curved line on the left side of the vertex y. The part shows a saturated liquid line.

In the area on the right side of the saturated vapor line, the refrigerant is superheated steam, and in the area on the left side of the saturated vapor line, the refrigerant is wet steam. Further, the refrigerant is in a liquid state in the area on the left side of the saturated liquid line, and the refrigerant is wet vapor in the area on the right side of the saturated liquid line.

Therefore, the low-pressure gaseous refrigerant sent from the evaporator 4 is converted into the high-temperature and high-pressure gaseous refrigerant by compressing it with the compressor 1 (between a and b in the figure), and then to the condenser 2. It sends in a gaseous refrigerant compressed to high temperature and high pressure.

By cooling the high-temperature high-pressure gaseous refrigerant sent from the compressor 1 with air or water in the condenser 2, heat is taken from the high-temperature high-pressure gaseous refrigerant and the gaseous refrigerant is liquefied. Then, the high-pressure liquid refrigerant is sent to the decompressor 3 (b-c in the figure).

The high-pressure liquid refrigerant is decompressed by the decompressor 3 and is converted into a low-temperature low-pressure liquid refrigerant that easily evaporates (between cd in the figure). And decompressor 3
The low-temperature liquid refrigerant sent from is evaporated by removing heat from the surroundings while passing through the evaporator 4, and the low-pressure gaseous refrigerant is sent into the compressor 1 again.

By repeating the above refrigeration cycle, the condenser 2 radiates heat and the evaporator 4 absorbs heat to generate refrigeration. Next, using the refrigeration system having the above structure, 1,1-difluoroethane (R152a) and 1,1,1-trifluoroethane (R143a) were mixed with isobutane (R6a).
00a) or octafluorocyclobutane (RC3
By changing the weight% of each component of the working fluid of the present invention mixed with any one of 18) by 1%, the five thermophysical properties (performance coefficient, refrigeration effect, discharge pressure, before and after evaporation) showing the performance of the heat pump device are shown. Refrigerant temperature difference and refrigerant temperature difference before and after condensation)
Was measured and compared with each thermophysical property value when R22 was used as the refrigerant. The results will be described below.

Table 1 shows the thermophysical properties of R22.
Table 2 shows a part of the measurement results of each thermophysical property value with respect to the mixing ratio of R152a, R143a and R600a.
Table 3 shows a part of the measurement results of each thermophysical property value with respect to the mixing ratio of R143a and RC318. The values in Tables 1 to 3 are values when the evaporation temperature is -5 ° C and the condensation temperature is 40 ° C, and the evaporation temperature and the condensation temperature are generally in the range of -5 to 40 in which the heat pump device is used. It was set based on being in ° C.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

Here, the coefficient of performance (hereinafter referred to as COP)
Here, the amount of work (the amount of change in the enthalpy of the evaporation process (d to a) shown in FIG. 2) showing the obtained refrigerating effect and the amount of work expended to obtain the freezing (compression process (a shown in FIG. 2 ~
b) Enthalpy change) ratio ((Ha-Hd) /
(Hb−Ha)), and the larger the COP, the better the energy efficiency of the refrigeration system.

The freezing effect (hereinafter referred to as Hi) is 1 kg
Is the amount of heat absorbed when the refrigerant liquid of FIG. 2 changes into vapor in the evaporator 4 (the amount of change in the enthalpy of the evaporation process (d to a) shown in FIG. 2) (Ha-Hd), and the higher this Hi, the higher the refrigeration system. Has a large endotherm.

The discharge pressure (hereinafter referred to as Pcond) is the pressure when the working fluid is discharged from the compressor 1 of FIG. The refrigerant temperature difference before and after evaporation (hereinafter referred to as Tv) is the difference in temperature of the working fluid before and after passing through the evaporator 4 in FIG.
When this difference becomes large, the refrigeration system may be frosted, and the heat exchange efficiency is reduced.

The refrigerant temperature difference before and after condensation (hereinafter referred to as Tc) is the difference between the temperatures of the working fluid before and after passing through the condenser 2 in FIG. 1. If this difference becomes large, the heat exchange efficiency of the refrigeration system will increase. Is reduced.

In the refrigeration system, this COP, Hi, Pc
Ond, Tv, and Tc are criteria for determining whether they are suitable as working fluids, and COP, Hi, and Pcond are particularly important criteria for configuring a refrigeration system. Further, if both Tv and Tc are 5 ° C. or less, the heat exchange efficiency of the refrigeration system is not reduced, and the frost is not attached to the evaporator 4.

First, R152a, R143a and R60
A working fluid as a first embodiment of the present invention in which 0a is mixed will be described with reference to the drawings shown in FIGS. 3 to 8, the vertical axis represents R600a and the horizontal axis represents R152a in weight%, and the balance represents R14a.
3a is occupied.

FIG. 3 shows the COP of the working fluid. The COP value (= 4.8) of R22 is set as an allowable lower limit, and a portion satisfying this is shown in a region Q ₁ . The numbers in the figure represent COP values, and the lines in the figure represent isolines.

FIG. 4 shows Hi of the working fluid. Since the Hi value of R22 is (= 155kJ / kg),
In this embodiment, the allowable lower limit of Hi is set to 150 kJ / kg, and a portion satisfying this is shown by a region R ₁ . The numbers in the figure are Hi
Values are shown, and the lines in the figure represent isolines.

FIG. 5 shows Pcond of the working fluid. In this embodiment, the Pcond value of R22 is 1537 kPa.
However, the allowable range of Pcond is set to 13 considering some margin.
00kPa ~ 1700kPa, and the part that satisfies this is the area S
Shown with ₁ . The numbers in the figure represent Pcond values, and the lines in the figure represent isolines.

FIG. 6 shows Tv of the working fluid. Since R22 is a single composition refrigerant, Tv is 0 ° C.
Is. In this embodiment, the allowable upper limit of Tv is set to 5 ° C., and a portion satisfying the upper limit is indicated by a region U ₁ .

FIG. 7 shows Tc of the working fluid. Tc of R22 is 0 ° C. because it is a refrigerant having a single composition like Tv. In this embodiment, the allowable upper limit of Tc is 5
The temperature is set to ° C, and the portion that satisfies this is indicated by a region V ₁ .

Based on the experimental results shown in FIGS. 3 to 7, the component ratios of R152a and R600a in which COP, Hi, Pcond, Tv, and Tc are in the above-mentioned allowable ranges, the point A (30, 20), point B (35,20), point C (45,1)
0), point D (45,0), point E (35,0) and point F (30,15)
In the range W ₁ surrounded by, the remainder is R134a and is composed of at least R152a and R143a. In this working fluid, ODP is 0, and COP, Hi, and Pcond have refrigerant characteristics equal to or higher than R22, and Tv and Tc are 5 ° C. or less as shown in FIGS. There is no risk of causing deterioration of exchange efficiency and adhesion of frost to the evaporator.

Next, R152a, R143a and RC3
A working fluid as a second embodiment of the present invention in which 18 is mixed will be described with reference to the drawings shown in FIGS. 9 to 14. 9 to 14, the vertical axis shows RC318 and the horizontal axis shows R152a in weight%, and the balance is R14.
3a is occupied.

FIG. 9 shows R152a, R143a and RC.
3 shows the COP of the working fluid composed of 318, and the COP value (= 4.8) of R22 is set as the allowable lower limit, as in FIG. 3, and the portion that satisfies this is shown in the region Q ₂ .

FIG. 10 shows the Hi of the working fluid. As with FIG. 4, the allowable lower limit of Hi (= 150 kJ / kg).
The above part is indicated by a region R ₂ . FIG. 11 shows the Pcond of the working fluid, and similarly to FIG. 5, a portion within the allowable range of Pcond (= 1300 kPa to 1700 kPa) is shown by a region S ₂ .

FIG. 12 shows the Tv of the working fluid, and similarly to FIG. 6, the region below the allowable upper limit value (= 5 ° C.) is shown by the region U ₂ . FIG. 13 shows Tc of the working fluid, and similarly to FIG. 7, a portion below the allowable upper limit value (= 5 ° C.) is shown by a region V ₂ .

Based on the experimental results shown in FIGS. 9 to 13, the component ratios of R152a and RC318 in which COP, Hi, Pcond, Tv, and Tc are in the above-mentioned allowable ranges, the point G (40, 25), point H (45, 0), point I (35, 0)
And a range of W ₂ surrounded by the point J (35,20), the balance being R143a, and at least R152a and R143
It is composed of a. With this working fluid, the ODP is 0 as in the case of the working fluid of the first embodiment described above.
In addition, COP, Hi and Pcond have refrigerant characteristics equal to or higher than R22, and as can be seen from FIGS. 12 to 14, Tv and Tc are 5 ° C. or less, lowering the heat exchange efficiency and reducing the efficiency of the evaporator. There is no risk of causing frost adhesion.

In the above embodiment, the working fluid is R1
52a and R143a two kinds of components, or the case of being composed of three kinds of components including either R600a or RC318 in these two kinds of components has been described.
In addition to these two or three components, a lubricating oil, a corrosion inhibitor, etc. may be mixed.

[0041]

As described above, according to the present invention, the working fluid contains two components of 1,1-difluoroethane and 1,1,1-trifluoroethane having an ozone depletion potential ODP of 0, or these two components. Since it is composed of three kinds of components including either isobutane or octafluorocyclobutane as the component (3), there is no risk of depleting the stratospheric ozone layer. In addition, since it has a refrigerant characteristic equal to or higher than that of R22 at the conventional operating temperature of the device, a higher coefficient of performance and a refrigerating effect than R22 can be expected, and the existing device can be used as it is as a substitute for R22. No new equipment needs to be replaced.

Further, the temperature difference between the working fluid before and after passing through the evaporator or the condenser is small, and there is no risk of lowering the heat exchange efficiency or causing frost to adhere to the evaporator.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a heat pump device tested with a working fluid of the present invention.

FIG. 2 is a Mollier diagram in the refrigeration cycle of the working fluid.

FIG. 3 is a diagram showing a coefficient of performance (COP) of the working fluid of the first embodiment.

FIG. 4 is a diagram showing a refrigerating effect (Hi) of the working fluid of the first embodiment.

FIG. 5 is a diagram showing a discharge pressure (Pcond) of a working fluid according to the first embodiment.

FIG. 6 is a diagram showing a refrigerant temperature difference (Tv) before and after evaporation of a working fluid according to the first embodiment.

FIG. 7 is a diagram showing a refrigerant temperature difference (Tc) before and after the working fluid is condensed in the first embodiment.

FIG. 8 is a diagram showing a desirable component ratio range of the working fluid of the first embodiment.

FIG. 9 is a diagram showing the coefficient of performance (COP) of the working fluid of the second embodiment.

FIG. 10 is a diagram showing a refrigerating effect (Hi) of the working fluid of the second embodiment.

FIG. 11 is a diagram showing a discharge pressure (Pcond) of a working fluid according to a second embodiment.

FIG. 12 is a diagram showing a refrigerant temperature difference (Tv) before and after evaporation of a working fluid according to a second embodiment.

FIG. 13 is a diagram showing a refrigerant temperature difference (Tc) before and after the condensation of the working fluid of the second embodiment.

FIG. 14 is a diagram showing a desirable component ratio range of the working fluid of the second embodiment.

[Explanation of symbols]

 1 Compressor 2 Condenser 3 Decompressor 4 Evaporator

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[Procedure amendment]

[Submission date] January 13, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] Figure 8

[Correction method] Change

[Correction content]

[Figure 8]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 14

[Correction method] Change

[Correction content]

FIG. 14

Front Page Continuation (72) Inventor Kenji Nasako 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (3)

[Claims] 1. A working fluid comprising 35 to 45% by weight of 1,1-difluoroethane and the balance 1,1,1-trifluoroethane, containing at least two components. 2. The ratio of 1,1-difluoroethane is 45% by weight or less, isobutane is 20% by weight or less, and the balance is 1,1,1-trifluoroethane. The ratio of 1,1-difluoroethane and isobutane is shown in the attached figure. Point A (30,20), Point B (35,20), Point C shown by solid line 8
(45,10), point D (45,0), point E (35,0) and point F (3
The working fluid is a range surrounded by 0, 15) and contains at least the above-mentioned three kinds of components. 3. 1,45% by weight or less of 1,1-difluoroethane, 25% by weight or less of octafluorocyclobutane, and the balance is 1,1,1.
1-trifluoroethane, wherein the component ratios of 1,1-difluoroethane and octafluorocyclobutane are shown by the solid line in the attached FIG. 14 at point G (40, 25), point H (45, 0), point I (35 , 0) and a point J (35, 20), and is a working fluid containing at least the above-mentioned three components.