JPH08231946A - Working fluid - Google Patents

Abstract

PURPOSE: To obtain a working fluid having null ozone destruction coefficient and refrigerant characteristics equal to or higher than R22, capable of using an existing apparatus as it is, utilizing R22. CONSTITUTION: This working fluid contains 35-60wt.% of 1,1,1-trifluoroethane, 25-55wt.% of 1,1-difluoroethane and the rest of difluoroethane and the weight percents (wt.%) of 1,1,1-trifluoroethane and 1,1-difluoroethane are in a range enclosed by a point A (35, 55), a point B (55, 45), a point C (60, 40), a point D (60, 30), a point E (55, 25), a point F (50, 25) and a point G (50, 30) shown on the solid lines of the figure. The working fluid contains at least the three components.

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.
F2, hereinafter referred to as R22) is used.

[0005]

The R22 is trichlorofluoromethane (C
Although the ozone depletion coefficient (hereinafter referred to as ODP), which indicates the stratospheric ozone depletion capacity of Cl3F, hereinafter referred to as R11), is 1 when the stratospheric ozone depletion capacity is set to 1, it is not a specified CFC, but it is a refrigeration / air conditioning equipment. With the widespread use of R22, 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, recently, various working fluids have been proposed in which a plurality of CFCs containing no chlorine are mixed in the molecular structure having ODP of 0. Then, Japanese Patent Laid-Open No. 3-
In 170592, difluoromethane (CH2F2) 6
0% by weight or less, 1,1,1-trifluoroethane (CH3CF
3) 80% by weight or less, 1,1-difluoroethane (CH3C
HF2) in a composition range of 20 to 65% by weight, and R
A working fluid having a vapor pressure almost equal to 22 has been proposed.

However, this Japanese Patent Laid-Open No. 3-17059
In the working fluid described in No. 2, among the refrigerant characteristics showing the performance of the heat pump device, vapor pressure, that is, thermophysical properties other than the discharge pressure of the working fluid in the evaporator and the condenser are not considered at all, Therefore, there is a possibility that the temperature difference between the working fluid before and after passing through the evaporator or the condenser may cause a decrease in heat exchange efficiency and adhesion of frost to the evaporator.

Therefore, the current equipment using R22 cannot be used as it is, and it is necessary to newly replace the equipment. The present invention has been made in view of such a point, and has an ODP of 0 and a refrigerant characteristic equal to or higher than that of R22, and the existing equipment using R22 can be used as it is. A working fluid is provided.

[0009]

The working fluid of the present invention comprises:
35 to 60% by weight of 1,1-trifluoroethane, 25 to 55% by weight of 1,1-difluoroethane, the balance being difluoromethane, and 1,1,1-trifluoroethane and 1,1-
The weight% of difluoroethane is shown by the solid line in FIG. 8 attached at point A (35,55), point B (55,45), point C (60,40), point D (6
0,30), point E (55,25), point F (50,25) and point G (50,25)
It is within the range surrounded by 30) and contains at least the above-mentioned three kinds of components.

[0010]

According to the present invention, each of the above working fluids is composed of a component that does not contain chlorine, has an ozone depletion coefficient of 0, and there is no risk of depleting the ozone layer in the stratosphere.

Each of the above working fluids has a coefficient of performance of 4.8 or more as a refrigerant, a refrigerating effect of 150 kJ / kg or more, a discharge pressure from a compressor of 1300 to 1700 kPa, before and after passing through an evaporator and a condenser. Since the temperature difference of the working fluid is 5 ° C or less and the temperature difference of the working fluid before and after passing through the evaporator or the condenser is small, there is no risk of lowering heat exchange efficiency and causing frost to adhere to the evaporator. In addition, it has a refrigerant characteristic equal to or higher than that of R22, and the existing equipment using R22 can be used as it is.

[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 chill. Next, using the refrigeration system having the above configuration, 1,1,1-
Trifluoroethane (hereinafter referred to as R143a), 1,1-
Five thermophysical properties showing the performance of the heat pump device by changing the weight% of each component of the working fluid of the present invention in which difluoroethane (hereinafter referred to as R152a) and difluoromethane (hereinafter referred to as R32) are mixed by 1%. (Grade coefficient,
The freezing effect, discharge pressure, refrigerant temperature difference before and after evaporation, and refrigerant temperature difference before and after condensation) were measured, and compared with the respective thermophysical property values 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 R143a, R152a and R32. The values in Tables 1 and 2 are the 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]

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, Pcond) is a pressure at which the working fluid is discharged from the compressor 1 shown in 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.

Next, R143a, R152a and R32
The working fluid of the present invention in which is mixed will be described with reference to the drawings shown in FIGS. 3 to 8. 3 to 8, the vertical axis represents R152a and the horizontal axis represents R143a in weight%, with the balance being R32.

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 (a). 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 the portion satisfying this is shown in the region (b). The numbers in the figure are H
The i 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, the area that satisfies this is the area
It shows with (c). The numbers in the figure represent the Pcond value,
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 the present embodiment, the allowable upper limit of Tv is set to 5 ° C., and a portion satisfying this is shown as a region (d).

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 be ° C, and a portion satisfying this is shown as a region (e).

Based on the experimental results shown in FIGS. 3 to 7, R1 in which COP, Hi and Pcond are within the above-mentioned permissible range
The component ratios of 43a and R152a are the points A (35,55), B (55,45), C (60,40), and D shown by the solid lines in FIG.
(60,30), point E (55,25), point F (50,25) and point G
It is the range (f) surrounded by (50,30) and the rest is R32.
Which is composed of the above three components. In this working fluid, ODP is 0, and COP and Hi have refrigerant characteristics equal to or higher than R22,
Moreover, Pcond has the same refrigerant characteristics as R22. Further, in the above range (f), Tv and Tc are 5 ° C. or less, and there is no fear of causing a decrease in heat exchange efficiency and adhesion of frost to the evaporator.

In the above embodiment, R1 is used as the working fluid.
Although the case where it is composed only of three kinds of components of 43a, R152a and R32 has been described, a lubricating oil, a corrosion inhibitor and the like may be mixed in addition to these.

[0035]

As described above, according to the present invention, the working fluid is mainly composed of three components of 1,1,1-trifluoroethane, 1,1-difluoroethane and difluoromethane having an ozone depletion potential of 0. Since it is configured, it does not destroy the ozone layer in the stratosphere even if the usage amount increases, and it can be suitably used as a refrigerant or the like.

The working fluid of the present invention has a coefficient of performance of 4.8 or more as a refrigerant, a refrigerating effect of 150 kJ / kg or more, a discharge pressure from a compressor of 1300 to 1700 kPa, before and after passing through an evaporator and a condenser. The temperature difference of the working fluid becomes 5 ° C. or less, there is no risk of lowering the heat exchange efficiency and causing frost to adhere to the evaporator, and R2 at the operating temperature of the conventional equipment.
Since it has a refrigerant characteristic equal to or higher than that of R2,
A coefficient of performance and a refrigeration effect higher than 2 can be expected, and existing equipment can be used as it is as an alternative to R22, and there is no need to newly replace equipment.

[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 present invention.

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

FIG. 5 is a diagram showing a discharge pressure (Pcond) of a working fluid of the present invention.

FIG. 6 shows a refrigerant temperature difference (T before and after evaporation of the working fluid of the present invention).
It is the figure which showed v).

FIG. 7: Refrigerant temperature difference before and after condensation of the working fluid of the present invention (T
It is the figure which showed c).

FIG. 8 is a diagram showing a desirable component ratio range of the working fluid of the present invention.

[Explanation of symbols] 1 compressor 2 condenser 3 pressure reducer 4 evaporator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Nasako 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (1)

[Claims] 1. 1,1,1-Trifluoroethane 35 to 60
%, 1,1-difluoroethane 25 to 55% by weight,
The balance is difluoromethane, and the weight% of 1,1,1-trifluoroethane and 1,1-difluoroethane is point A (35,55) and point B shown by the solid line in the attached FIG.
(55,45), point C (60,40), point D (60,30), point E (55,
25), a working fluid within a range surrounded by points F (50,25) and G (50,30) and containing at least the above-mentioned three components.