KR19990053764A - Mixed refrigerant composition for refrigeration / air conditioner - Google Patents

Abstract

The present invention relates to a mixed refrigerant capable of replacing CFC-12, in which 10 to 98 wt% of 1,1,1,2 tetrafluoroethane, 2 to 70 wt% of dimethyl ether and chlorodifluoromethane, propane or isobutane It relates to a near azeotropic and non-azeotropic mixed refrigerant, which is selected so as to contain 0 to 20wt% of one selected.

The mixed refrigerant of the present invention has a low possibility of ozone depletion and is an alternative refrigerant to CFC-12, which has been widely used in conventional refrigerators and air conditioners for automobiles, and shows excellent effects in the freezing performance coefficient and the freezing volume of the compressor. It can effectively replace CFC-12 without changing lubricant.

Description

Mixed refrigerant composition for refrigeration / air conditioner

The present invention includes a plurality of halogenated hydrocarbons that can be used as refrigerants in refrigerators and air conditioners; Refrigerant Mixtures comprising a dimethyl ether; as a main component and is made to contain any one selected from propane or isobutane. More specifically, the present invention relates to a mixed refrigerant composition capable of replacing dichlorodifluoromethane (CCI ₂ F ₂ : hereinafter referred to as CFC-12) used in household refrigerators and automobile air conditioners.

Conventionally, chlorofluorofluorocarbons (hereinafter referred to as CFCs) derived from methane or ethane and hydrogen are used as refrigerants such as refrigerators, air conditioners and heat pumps (Hydro-Chloro). Fluoro-Carbon (hereinafter referred to as HCFC) has been mainly used, and CFC-12 having a boiling point of -29.79 ° C and a molecular mass of 120.93kg / kmol has been most widely used in automobile air conditioners and household refrigerators. .

In recent years, the destruction of the stratospheric ozone layer by CFCs has emerged as an important global environmental protection problem, and the use and production of CFCs containing chlorine and being fully halogenated and potentially ozone depleted are severely restricted by the Montreal Protocol. CFC-12 is the Ozone depleting potential (hereinafter referred to as ODP, which is used internationally as the reference of CFC-11 with ODP as 1.0), which is one of the larger CFC refrigerants (ODP = 0.9. The production and use of this document is restricted by the Montreal Protocol, an international convention organized by the United Nations Environment Agency. As a result, most countries are currently using alternative refrigerants with near-zero ODPs, such as HCFCs, or zero ODPs, such as HFCs, and many research and development investments are underway to develop them.

In order for an alternative refrigerant to be used as an alternative to the CFC-12 without significantly modifying the existing CFC-12 compressor, it must have a vapor pressure similar to that of the CFC-12, and a similar Coefficient of Performance (hereinafter referred to as COP). Must have Here, the COP refers to the total refrigeration effect compared to the work applied to the compressor. The larger the COP, the better the energy efficiency of the freezer.

On the other hand, the most important factor with COP in the design of the refrigerator is the volumetric capacity (hereinafter referred to as VC). VC is a refrigeration effect per unit volume (unit: kJ / m ³ ), which is proportional to the vapor pressure and represents the size of the compressor. If an alternative refrigerant can provide the refrigeration capacity of the existing CFC-12, it is very advantageous for the manufacturer to manufacture the refrigerator without changing the size of the compressor.

As a result of the research, it is well known that the replacement of CFC-12 with a single material refrigerant requires inevitably to replace the compressor because the volume of the replacement refrigerant is different, and it is difficult to obtain a performance coefficient similar to that of CFC-12. One way to solve this problem is to use a mixed refrigerant with similar properties to CFC-12.

The characteristic of the mixed refrigerant is that if the composition is well blended to give the same vapor pressure as the existing refrigerant and at the same time, the same lubricant can be used, there is no need to change the compressor. Due to these characteristics, various mixed refrigerants have been proposed in the last few years as a substitute for CFC-12.

DuPont, USA, trade names MP-39 (53% HCFC-22 / 34% HFC-124 / 13% HCFC-152a), MP-66 (61% HCFC-22 / 28% HFC-124 / Three-way mixed refrigerants such as 11% HCFC-152a) and MP-52 (33% HCFC-22 / 52% HFC-124 / 15% HCFC-152a) have been developed and are now commercially available. Air Tech Co., Ltd. has developed and marketed a three-way mixed refrigerant called GHG-X3 (65% HCFC-22 / 4% R600a / 31% HCFC-142b) consisting of HCFC and hydrocarbons. A three-way mixed refrigerant, known as FRIGC (39% HFC-124 / 59% HFC-134a / 2% R600), consisting of HFC and hydrocarbons, has been developed and marketed. In addition to these various mixed refrigerants are being applied to a specific refrigeration / air conditioner.

It is an object of the present invention to provide a mixed refrigerant that has little effect on the ozone layer in the stratosphere (ODP 0.01 or less) and can be used as a replacement for CFC-12 without changing compressors or lubricants.

1 is a block diagram of a refrigeration / air conditioner using the composition of the present invention.

-Explanation of symbols for the main parts of the drawings-

Qc: Heat flow direction from the condenser (from refrigerant to air)

Qe: Heat flow direction from the evaporator (air to refrigerant)

TS1: Evaporator air inlet temperature, TS7: Evaporator air outlet temperature

TS3: condenser air outlet temperature, TS6: condenser air inlet temperature

2: evaporator 4: condenser

6: compressor 8: expansion valve

The present invention is a binary mixed refrigerant composed of 1,1,1,2 tetrafluoroethane (hereinafter referred to as HFC 134a) and dimethyl ether (hereinafter referred to as RE-170) and chlorodifluoromethane in the binary mixed refrigerant. (Hereinafter referred to as HCFC-22), propane (hereinafter referred to as R-290), or isobutane (hereinafter referred to as R-600a) relates to a three-way mixed refrigerant mixed. The present invention provides a near-azeotropic refrigeration mixture and a non-azeotropic mixed refrigerant approach to, or in many cases better than, the CFC-12's COP and compressor's VC compared to commercially available CFC-12 alternatives. Non-azeotropic Refrigerant Mixture.

In order to develop CFC-12 alternative refrigerants, we first created a program that simulates the performance of a refrigeration / air conditioner. 1 is a block diagram of a general refrigeration / air conditioner used in the present invention and is composed of an evaporator, a condenser, a compressor, an expansion valve, and the like. The program first performed thermodynamic and heat transfer analyzes of the components that make up the refrigeration / air conditioner, such as heat exchangers and compressors, and finally developed a complete program that combined them all. One of the important factors that determine the accuracy of this program is the properties of refrigerants. In this program, the physical properties of all refrigerants were calculated using the CDS equation (Carnahan-Starling-De Santis, hereinafter referred to as CSD) developed by the American Institute of Standards and based in the United States and Japan. This state equation has already proven its accuracy and applicability. The design and input data for the development and implementation of the refrigeration / air conditioning program created this time uses existing data as far as possible.

The inventors have determined that the ozone depletion potential of CFC-12 alternative refrigerants for refrigeration / air conditioners should be very low, and HCFC-22 or natural refrigerants R-290 or R-600a, HFC-134a and ether-based RE-170. Combinations were made to replace CFC-12.

Table 1 summarizes the results calculated using the computational analysis program under specific conditions, and shows the comparison of the performance indices of the reference CFC-12 and the proposed CFC-12 alternative mixed refrigerants. Table 1 shows that the refrigerants of the embodiments are similar or larger in terms of refrigerating capacity and coefficient of performance than the conventional CFC-12. In addition, the temperature gradient shows a maximum porosity of 1.64 ℃, and ODP is about 1.0% of CFC-12, which is much better than CFC-12 in terms of environmental preservation. The pressure ratio is also similar to that of CFC-12, which is expected to be no problem for the compressor.

Comparison of theoretical performance of CFC-12 and the mixed refrigerant of the present invention Refrigerant Furtherance(%) COP VC (kJ / m ³ ) GTD (℃) ODP PR COP difference (%) VC difference (%) HCFC-22 HFC-134a RE-170 R-12 - - - 2.165 1876 0.00 1.000 4.28 0.0 0.0 Example 1 0 98 2 2.105 1907 0.00 0.000 4.90 -2.8 1.7 Example 2 0 80 20 2.195 1909 0.04 0.000 4.79 1.4 1.7 Example 3 0 60 40 2.260 1896 0.06 0.000 4.72 4.4 1.1 Example 4 0 40 60 2.305 1879 0.06 0.000 4.68 6.5 0.2 Example 5 0 30 70 2.322 1871 0.05 0.000 4.66 7.3 -0.3 Example 6 10 88 2 2.138 2045 1.00 0.005 4.76 -1.2 9.0 Example 7 10 70 20 2.224 2017 0.87 0.005 4.69 2.7 7.5 Example 8 10 50 40 2.286 1982 0.77 0.005 4.64 5.6 5.7 Example 9 10 30 60 2.327 1951 0.69 0.005 4.61 7.5 4.0 Example 10 10 20 70 2.343 1936 0.64 0.010 4.60 8.2 3.2 Example 11 20 78 2 2.169 2180 1.64 0.010 4.63 0.2 16.2 Example 12 20 60 20 2.251 2123 1.48 0.010 4.59 4.0 13.2 Example 13 20 40 40 2.309 2067 1.34 0.010 4.56 6.7 10.2 Example 14 20 20 60 2.347 2020 1.21 0.010 4.54 8.4 7.7 Example 15 20 10 70 2.362 2000 1.14 0.010 4.53 9.1 6.6 Example 16 10 80 10 2.181 2033 0.93 0.005 4.72 0.7 8.4 ※ ○ COP: Coefficient of Performance = ○ VC: Volumetric capacity of compressor ○ GTD: Gliding Temperature Difference, if it is below 9 ℃, there is no problem in actual system ○ ODP: Ozone Depletion Index (If possible may lower) ○ PR: the compressor discharge pressure and the suction pressure ratio (good is similar to the standard refrigerants) ○ COP _diff: R-12 differences compared to frozen coefficients ○ VC _diff: R-12 differences compared to the compressor capacity

In order to prove the above theoretical results, a refrigeration system was built and tested in a car air conditioner. The experimental results are as described in Table 2 below. As can be seen from Tables 1 and 2, the performance coefficient and capacity of the embodiment of the present invention were found to be good compared to CFC-12, and the compressor discharge temperature was about 1.5 ° C. higher than that of CFC-12. No problem appeared.

Comparative Table of Experimental Performance of CFC-12 and Alternative Mixed Refrigerants Refrigerant Furtherance(%) COP QE (W) Dis.Temp (℃) COP difference (%) QE difference (%) HCFC-22 HFC-134a RE-170 R-12 - - - 3.303 3820 76.0 0.0 0.0 Example 16 10 80 10 3.396 3963 77.5 2.8 3.7 ※ QE: Evaporator capacity available when using the same compressor.Dis. Temp: Compressor discharge temperature (No problem if within ± 10 ℃ of standard refrigerant)

On the other hand, since CFC-22 is HCFC, there is a possibility of destroying ozone, so in the long run, propane (R-290) or isobutane (R-600a), which is harmless to ozone (ODP: 0.0), may be used instead of HCFC-22. Tables 3 and 4 below calculate the performance of R-290 / R-134a / RE-170 mixed refrigerant and R-600a / R-134a / RE-170 mixed refrigerant through the same computational analysis. The ozone decay index of the two mixed refrigerants is 0.0, which is harmless to the ozone layer, and its performance coefficient or volume capacity is similar to or higher than that of the existing CFC-12, so there is no problem in replacing CFC-12. It is also well known in the art that R-290 or R-600a are hydrocarbons, and if a small amount of hydrocarbons enters the refrigeration system, the lubricity and mixing of the oil can be increased to greatly increase the reliability of the compressor. On the other hand, the refrigerant containing R-290 is non-azeotropic and has a temperature gradient of up to 7.99 ° C. The refrigerant containing R-600a has a temperature gradient of up to 1.71 ° C due to near azeotropy. It is superior to existing used products.

Comparison of theoretical performance of CFC-12 and R-290 / R-134a / RE-170 mixed refrigerants Refrigerant Furtherance(%) COP VC (kJ / m ³ ) GTD (℃) ODP PR COP difference (%) VC difference (%) R-290 R-134a RE-170 R-12 - - - 2.165 1876 0.00 1.000 4.28 0.0 0.0 Example 17 0 98 2 2.105 1907 0.00 0.000 4.90 -2.8 1.7 Example 18 0 90 20 2.195 1909 0.04 0.000 4.79 1.4 1.7 Example 19 0 60 40 2.260 1896 0.06 0.000 4.72 4.4 1.1 Example 20 0 40 60 2.305 1879 0.06 0.000 4.68 6.5 0.2 Example 21 0 30 70 2.322 1871 0.05 0.000 4.66 7.3 -0.3 Example 22 10 50 40 2.241 2252 7.81 0.000 4.39 3.5 20.1 Example 23 10 30 60 2.259 2171 6.34 0.000 4.39 6.0 15.7 Example 24 10 20 70 2.315 2137 5.75 0.000 4.40 6.9 13.9 Example 25 20 40 40 2.199 2456 7.99 0.000 4.16 1.6 30.9 Example 26 20 20 60 2.265 2349 7.05 0.000 4.20 4.6 25.2 Example 27 20 10 70 2.290 2303 6.62 0.000 4.21 5.8 22.8

Theoretical Performance Comparison of R-12 and R-600a / R-134a / RE-170 Mixed Refrigerants Refrigerant Furtherance(%) COP VC (kJ / m ³ ) GTD (℃) ODP PR COP difference (%) VC difference (%) R-600a R-134a RE-170 R-12 - - - 2.165 1876 0.00 1.000 4.28 0.0 0.0 Example 28 0 98 2 2.105 1907 0.00 0.000 4.90 -2.8 1.7 Example 29 0 80 20 2.195 1909 0.04 0.000 4.79 1.4 1.7 Example 30 0 60 40 2.260 1896 0.06 0.000 4.72 4.4 1.1 Example 31 0 40 60 2.305 1879 0.06 0.000 4.68 6.5 0.2 Example 32 0 30 70 2.322 1871 0.05 0.000 4.66 7.3 -0.3 Example 33 10 70 20 2.125 2028 1.71 0.000 4.53 -1.8 8.1 Example 34 10 50 40 2.211 1978 1.21 0.000 4.53 2.1 5.5 Example 35 10 30 60 2.268 1937 0.85 0.000 4.53 4.8 3.2 Example 36 10 20 70 2.289 1919 0.70 0.000 4.38 5.7 2.3 Example 37 20 40 40 2.170 1969 0.55 0.000 4.44 0.2 4.9 Example 38 20 20 60 2.233 1925 0.37 0.000 4.46 3.1 2.6 Example 39 20 10 70 2.257 1906 0.26 0.000 4.46 4.2 1.6

The mixed refrigerant of the present invention has an advantage that the ODP is extremely low and can be usefully used as an alternative refrigerant of CFC-12 without changing the compressor or lubricating oil of the refrigeration / air conditioner using the conventional CFC-12.

Claims (1)

In the mixed refrigerant for refrigeration / air conditioner, any one selected from 10 to 98 wt% of 1,1,1,2 tetrafluoroethane, 2 to 70 wt% of dimethyl ether, and chlorodifluoromethane, propane or isobutane Azeotropic and azeotropic mixed refrigerants formulated to contain 20wt%.