JPH04110386A - heat transfer fluid - Google Patents

Abstract

PURPOSE:To obtain the title fluid which is useful, for the use in a refrigerator, heat pump or the like and has no tendency to destruct the ozone layer by using a specific organic compound. CONSTITUTION:The title fluid comprises an organic compound represented by formula Rf-O-Rf or formula Rf-O-R, wherein Rf represents CF3, CF2H, CFH2, C2F5, C2F4H, C2F3H2, C2F2H3 or C2FH4; and R represents CH3 or C2H5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to heat transfer fluids used in refrigerators, heat pumps, etc.

In this specification, "%" means "% by weight".

BACKGROUND ART Conventionally, as heat carriers (refrigerants) for heat pumps, chlorofluorohydrocarbons, fluorohydrocarbons, azeotropic compositions thereof, and compositions in the vicinity thereof have been known. These are generally called fluorocarbons, and currently R-11 (lichloromonofluoromethane), R-22 (monochlorodifluoromethane), R-502 (R-22+chloropentafluoroethane), etc. are mainly used. has been done.

However, in recent years, it has been pointed out that certain types of fluorocarbons, when released into the atmosphere, destroy the ozone layer in the stratosphere and, as a result, have a serious negative impact on the global ecosystem, including humans. Therefore, the use and production of fluorocarbons, which pose a high risk of ozone layer depletion, has been regulated by international agreements. CFCs that are subject to regulations include R-11 and R-12.
Furthermore, R-22 is not currently subject to regulation because it has a small effect on ozone layer depletion, but in the future it is hoped that a refrigerant with less effect will emerge. Regulations on the use and production of fluorocarbons, whose demand is increasing every year with the spread of refrigeration and air-conditioning equipment, are having an extremely large impact on the current social system as a whole, including the living environment. Therefore, there is an urgent need to develop a new heat medium (refrigerant) for heat pumps that has no or very low risk of causing ozone layer depletion.

Means for Solving the Problem The present inventor has proposed a heat transfer fluid suitable for a heat pump or a heat engine, and of course containing air [:I=
Various studies have been carried out to obtain a new heat transfer fluid that has little or no effect on the ozone layer even if it is released. As a result, they found that organic compounds with a specific structure meet the requirements for the purpose.

That is, the present invention provides a heat pump having the following molecular formula: Rf-0-Rf (1) or Rf-0-R
(2) (Rf is CF3.CF2 H, CFH2゜C2F5
, C2F4 H, C2Fa R2.

represents C2F2R3 or C2FH; however, in the compound represented by molecular formula (1), two Rf may be the same or different; R is CH
3 or C2H5). The main physical properties of each compound used in the present invention are as follows.

1, F3C-0-CH3 Boiling point -24,0°C Critical temperature 1]2°C Critical pressure 43kg/C Molecular weight 100.04 II, CF2HOCF2 H (tetrafluorodimethyl ether) Boiling point Critical temperature Critical pressure Molecular weight m, CFH2 - Chill) Boiling point -7.0°C Critical temperature 1:34.9°C Critical pressure 45. 2kg/cnff molecular weight
82.05 The compounds represented by formulas (1) and (2) used as heat transfer fluids in the present invention do not contain chlorine atoms and bromine atoms that affect the ozone layer, so they do not cause the problem of ozone layer destruction. There is no risk of this occurring.

In addition, since compounds with ether bonds are relatively easy to decompose in the atmosphere, the compounds used in the present invention have the advantage of having a small impact on global warming. 118.03 0CFH2 (also contains difluorodimethylethyl).

On the other hand, the compound used in the present invention has excellent properties as a heat medium for heat pumps, and is well balanced in performance such as coefficient of performance, refrigeration capacity, condensation pressure, and discharge temperature. Furthermore, the boiling point of this compound is close to that of R12, R, -22, R-1:1.4 and R-502, which are currently widely used, so that it can be used under the conditions of use of these known heat carriers, that is, the evaporation temperature. -20°C] and condensing temperatures from 30 to 60°C.

Furthermore, the present invention includes at least a compound represented by formula (1) or (2), and R-22(CFCF2
), R32(CH2F2).

R-124(CF2Cl(IF), R-125(CF
3CF2H), R-134,a(CF,, CFH),
A mixture containing at least one selected from the group consisting of R-1,42b (CH3CCQF2), R143a (CF3CH3) and R-152 (CHF2CH3) may be used as the heat transfer fluid. When using this mixture, the refrigeration capacity can be further improved by mixing a low boiling point refrigerant,
By mixing a refrigerant with a large latent heat of vaporization, the coefficient of performance can be improved or the compatibility with refrigerating machine oil can be improved.

The compound of formula (1) or (2) used in the present invention or these compounds and R-22, R-32, R124, R-1
25, a mixture with at least one of R-134a, R-142b, R-143a and R-152a has the general characteristics required for a heat medium for a heat pump (for example, compatibility with lubricating oil, (non-corrosive to materials, etc.)
It has been confirmed that there are no problems with this.

The following remarkable effects are achieved.

(1) Cycle performance equivalent to or higher than that of heat pumps that have conventionally used R-12, R-22, or R502a as a heat medium can be obtained.

(2) Because of the excellent performance of the compounds represented by formulas (1) and (2) used as heat carriers, they are advantageous in terms of device design.

(3) Even if the heat transfer medium were to be released into the atmosphere, there would be no risk of ozone layer depletion and the impact on global warming would be small.

EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention.

Example 1 and Comparative Examples 1 to 3 In a 1-horsepower heat pump that uses F3 C-0-CH3 (trifluoromethyl methyl ether) as a heat medium, the evaporation temperature of the heat medium in the evaporator was set to -10°.
C1-5°C, 5°C and 10°C, the condensation temperature in the condenser was 50°C, and the degree of superheating and supercooling were 5°C and 3°C, respectively.

In addition, as comparative examples, R, -12 (comparative example 1), R-2
The heat pump was operated under the same conditions as above using R-502 (Comparative Example 2) and R-502 (Comparative Example 3) as heat transfer media.

From these results, the coefficient of performance (COP) and refrigeration effect were determined using the following equations (see the Mollier diagram shown in FIG. 1).

C0P-(hl h4)/(h2 hl) freezing effect-
ri, -h, l hl... Enthalpy of heat medium at Taguchi of evaporator h2...
・Enthalpy h4 of the heat medium at the inlet of the condenser Enthalpy of the heat medium at the inlet of the evaporator The circuit diagram of the refrigeration cycle used in this example and the comparative example is shown in FIG.

The calculation results of COP and refrigerating capacity are shown in FIG. 3 and FIG. 4, respectively, in comparison with the results of Comparative Examples 1 to 3.

The coefficient of performance shown in Figure 3 is the measured value (COPB) at an evaporation temperature of 5°C when R-22 is used as the heat medium, divided by the measured value (COPA) of each heat medium. . In particular, the results of the heat transfer medium according to the present invention are indicated by "○".

In addition, the refrigerating capacity shown in Fig. 4 is obtained by dividing the measured value (capacity A) of each heat medium by the measured value (capacity B) at an evaporation temperature of 5°C when R-22 is used as the working fluid. It is. The results of the heat transfer medium according to the present invention are also indicated by "○".

As is clear from FIG. 3, the heat medium according to this example is c
Regarding op, it shows a value as good as R-12 and R22. Furthermore, as is clear from FIG. 4, the refrigeration effect shows a slightly higher value than R22.

Further, Table 1 shows the comparison results of the condensing pressure and compressor discharge temperature at an evaporation temperature of 5°C.

Table 1 Condensing pressure Discharge temperature (kg/cpo・A) ('O Example 1 11 51 Comparative example 1
12 59 Comparative Example 2 20
7B Comparative Example 3 22 The condensation pressure and discharge temperature of the heat medium according to this example are R
-12, which is advantageous in terms of device design.

From the above results, in this example using F3C-0-CH3 as the heat medium, cycle performance equivalent to that of heat pumps using R-12, R-22, and R502, which have been widely used in the past, can be obtained. Therefore, it is clear that the present invention is advantageous in terms of equipment design.

Example 2 A heat pump was operated in the same manner as in Example 1 except that CF2 HOCF2 H (tetrafluorodimethyl ether) was used as the heat medium and the evaporation temperature of the heat medium in the evaporator was set to 5°C.

The coefficient of performance and freezing capacity are shown in Table 2 below.

Both values are measured values of evaporative humidity at 5°C (COPB and refrigeration capacity B) when R-22 is used as a heat medium.
) is the value obtained by dividing the measured values (CoPA and capacity A) of the heat transfer medium of this example.

Example 2 COPA /C0PB 1, 00 Capacity A / Capacity 8 0.46 Example 3 Using CFH20CFH2 2 Table-12R 1,02 0,61 0,92 1,03 (difluorodimethyl ether) as a heat medium, The heat pump was operated in the same manner as in Example 1 except that the evaporation temperature of the heat medium in the evaporator was 5°C.

The coefficient of performance and freezing capacity are shown in Table 3 below.

Both values are measured values at the evaporation temperature of 5°C (COPB and refrigeration capacity B) when R-22 is used as the heat medium.
) is the value obtained by dividing the measured values (COPA and capacity A) of the heat transfer medium of this example.

Table 3 Example 3 R, -12R, -502 COPA/C0PB 1.051.02 0.92 Capacity A/Capacity, 0.36 0.61
1.03

[Brief explanation of the drawing]

FIG. 1 is a Mollier diagram used to determine the coefficient of performance (COP) and freezing effect in the examples. FIG. 2 is a circuit diagram of a refrigeration cycle used in this example and a comparative example. FIG. 3 shows COPs according to Examples]- and Comparative Examples 1 to 3.
This is a graph showing. FIG. 4 is a graph showing the refrigerating capacity of Example 1 and Comparative Examples 1 to 3. (that's all)

Claims (1)

[Claims] 1. Molecular formula: Rf-O-Rf (1) or Rf-O-R (2) (Rf is CF_3, CF_2H, CFH_2, C_2
F_5, C_2F_4H, C_2F_3H_2, C_2
Represents F_2H_3 or C_2FH_4; However, in the compound represented by molecular formula (1), two Rf may be the same or different; R is CH
_3 or C_2H_5).