KR100540280B1 - R502 and r22 substitute mixed refrigerant and refrigeration system using thereof - Google Patents

Abstract

The present invention relates to a mixed refrigerant for replacing R502 and R22 used in a vapor compression refrigerator or an air conditioner and a refrigeration system using the same, and more particularly, to replace an existing refrigeration system without causing ozone layer destruction and global warming. Propylene, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane, dimethyl ether and isobutane which can be used without It is about. Mixed refrigerant according to a preferred embodiment of the present invention is 30 to 70% by weight of R1270 (propylene), 1 to 69% by weight of R134a (1,1,1,2-tetrafluoroethane), R152a (1,1-difluoro Roethane) 1 to 69% by weight.

Description

R502 AND R22 SUBSTITUTE MIXED REFRIGERANT AND REFRIGERATION SYSTEM USING THEREOF}

The present invention is a mixture composed of an optional combination of a material that can be used as a refrigerant (referred to as R) in a vapor compression refrigeration / air conditioner, namely propylene, R134a, R152a, dimethyl ether (hereinafter referred to as DME) and isobutane. Refrigerant and refrigeration system using the same, and more specifically, monochloro fluoride, which has been widely used in low temperature freezers and transport refrigerators (hereinafter referred to as CFC502), and home air conditioners and commercial air conditioners. The present invention relates to a mixed refrigerant capable of replacing romethane (CHClF ₂ , hereinafter R22 or HCFC22) and a refrigeration system using the same. CFC502 is an azeotropic mixed refrigerant comprising 48.8% by weight monochlorofluoromethane (hereinafter referred to as R22 or HCFC22) and 51.2% by weight chloropentafluoroethane (hereinafter referred to as R115 or CFC115).

Until now, chlorofluorocarbons (hereinafter referred to as CFCs) and hydrochlorofluorocarbons (hereinafter referred to as CFCs) derived from methane or ethane have been mainly used as refrigerants for refrigerators, air conditioners, and heat pumps. CFC502, which has a boiling point of -45.4 ° C and a molecular mass of 111.6 kg / kmol, has been the most widely used in freezers, transport freezers, supermarket freezers, etc., and has a boiling point of -40.8 ° C and a molecular mass of 86.47 kg for household air conditioners and commercial air conditioners. HCFC22, / kmol, has been the most widely used.

Recently, however, the destruction of the stratospheric ozone layer by CFCs and HCFCs has emerged as an important global environmental problem, and the production and consumption of stratospheric ozone-depleting CFCs and HCFCs is regulated by the Montreal Protocol, created in 1987. The CFC502 and HCFC22 have high Ozone Depletion Potential (ODP) of 0.18 and 0.05, respectively, so that in developed countries, they will be fully or fully pursuant to the Montreal Protocol. You are trying to use an alternative refrigerant with.

Recently, not only the ozone depletion problem but also the global warming problem has begun to emerge rapidly, and the 1997 Kyoto Protocol strongly recommends refusing to use HFC refrigerants with high global warming potential (GWP). . Reflecting this trend, European and Japanese refrigerator manufacturing companies use isobutane (hereinafter referred to as R600a) as a refrigerant in almost all refrigerators and produce household air conditioners, heat pumps, low temperature freezers and automobile air conditioners. Some are also trying to use hydrocarbon-based refrigerants with a low global warming index (GWP).

Table 1 shows the environmental indices of some refrigerants.

Environmental Index of Refrigerants Refrigerant Ozone Depletion Index (ODP) Global Warming Index (GWP) CFC12 0.9 8,500 HFC134a 0.0 1,300 HCFC22 0.05 1,700 R407C 0.0 1,370 CFC502 0.18 4,510 R404A 0.0 3,850 HFC125 0.0 3,200 HFC143a 0.0 4,400 HFC152a 0.0 140 Propylene (R1270) 0.0 3 or less Propane (R290) 0.0 3 or less DME (RE170) 0.0 3 or less Isobutane (R600a) 0.0 3 or less

(*) ODP is based on CFC11 as 1.0.

(**) GWP is based on a 100-year carbon dioxide standard of 1.0.

As shown in Table 1, propylene, propane, isobutane, DME, and HFC152a have an ozone depletion index (ODP) of 0.0 and a global warming index (GWP). This is why most countries in the European Union, Japan and Asia now mix refrigerants with an ODP of 0.0 and lower GWP than conventional CFC or HFC refrigerants to achieve the desired thermodynamic properties while at the same time improving efficiency or increasing oil compatibility. To achieve. In this sense, propylene, propane, isobutane, DME, and HFC152a are eligible.

In order for a material to be useful as an alternative to a conventional refrigerant, it must first have a coefficient of performance (COP) similar to that of a conventional refrigerant. The coefficient of performance (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 refrigeration / air conditioner. In addition, in order to use the compressor without major modifications, the alternative refrigerant must have a vapor pressure similar to that of the existing refrigerant and ultimately provide a similar volumetric capacity (VC). Here, the volumetric capacity (VC) refers to the refrigeration effect per unit volume, which is a factor indicating the size of the compressor, which is usually proportional to the vapor pressure and is in kJ / m 3. If the replacement refrigerant has a volume capacity similar to that of the existing refrigerant, it is very advantageous for manufacturers to build refrigeration / air conditioning without changing compressors or making major modifications. However, studies to date have shown that in case of replacing the existing refrigerant with pure material, the volume of the replacement refrigerant is different, so it is inevitable to change or largely modify the compressor, and it is difficult to obtain a similar coefficient of performance as the existing refrigerant.

One way to solve this is to use a mixed refrigerant. The characteristics of mixed refrigerants are that they can be formulated so that their coefficients of performance are similar to those of conventional refrigerants, while at the same time providing a volumetric capacity (VC) similar to conventional refrigerants, thereby eliminating the need for major modifications to the compressor. Due to these characteristics, several mixed refrigerants have been proposed as substitutes for CFC502 and HCFC22 in the past few years, but some of them have HCFCs which are prohibited from use in the Montreal Protocol, and thus are not suitable alternatives in the long term.

Dupont of the United States has developed a three-way mixed refrigerant, R404A (44% by weight R125 / 52% by weight R143a / 4% by weight, R134a) that does not cause ozone decay, but this refrigerant is less energy efficient than R502, thus inducing the indirect effects of global warming. It is a suitable alternative in the long term because it consists only of HFCs that may be accelerated and limit the use in the Kyoto Protocol. In addition, the three-way mixed refrigerant R407C (23 wt% R32 / 25 wt% R125 / 52 wt% R134a), developed by DuPont, USA, has a freezing capacity similar to that of the conventional HCFC22, but its energy efficiency is low and the temperature gradient is 7 ° C. If the system is leaking to a degree, there is a disadvantage in that the composition is separated. Meanwhile, Allied Signal Co., Ltd. has developed and sold a binary mixture refrigerant (50% by weight R32 / 50% by weight R125) called R410A. However, this refrigerant has a vapor pressure of about 60% higher than the conventional HCFC22. Because of the high pressure, the strength of the material used in the condenser must be increased.

The present invention has been made to solve the above problems of the prior art, an object of the present invention is propylene, 1,1,1,2-tetrafluoroethane, 1,1 which is a substance that does not cause ozone layer destruction and global warming -By using a combination of difluoroethane, dimethyl ether and isobutane in an appropriate composition ratio to provide a mixed refrigerant and a refrigeration system using the same to replace the existing refrigeration system directly or without significant modification.

The object of the present invention described above is 30 to 70% by weight of R1270 (propylene), 1 to 69% by weight of R134a (1,1,1,2-tetrafluoroethane), R152a (1, 1-difluoroethane) can be achieved by a mixed refrigerant consisting of 1 to 69% by weight.

In order to achieve the above object, 30 to 70% by weight of R1270 (propylene), 1 to 40% by weight of R134a (1,1,1,2-tetrafluoroethane), R152a (1, 1-difluoroethane) preferably from 20 to 30% by weight.

In addition, the object of the present invention described above is 30 to 80% by weight of R1270 (propylene), 1 to 69% by weight of R134a (1,1,1,2-tetrafluoroethane), RE170 (dimethyl) Ether) can also be achieved by a mixed refrigerant consisting of 1 to 69% by weight.

In order to achieve the above object, 30 to 70% by weight of R1270 (propylene), 1 to 50% by weight of R134a (1,1,1,2-tetrafluoroethane) and RE170 (dimethyl ether) in a mixed refrigerant for refrigeration / air conditioner It is preferably composed of 20 to 40% by weight.

In order to achieve the above object, 50 to 80% by weight of R1270 (propylene), 1 to 20% by weight of R134a (1,1,1,2-tetrafluoroethane) and RE170 (dimethyl ether) in a mixed refrigerant for refrigeration / air conditioner ) Is preferably composed of 1 to 30% by weight.

In addition, the object of the present invention described above is 30 to 70% by weight of R1270 (propylene), 1 to 69% by weight of R134a (1,1,1,2-tetrafluoroethane), R600a (iso) in a mixed refrigerant for refrigeration / air conditioner Butane) can also be achieved by a mixed refrigerant consisting of 1 to 69% by weight.

In order to achieve the above object, 30 to 70% by weight of R1270 (propylene), 10 to 60% by weight of R134a (1,1,1,2-tetrafluoroethane) and R600a (isobutane) in a mixed refrigerant for a refrigerator / air conditioner ) 1 to 20% by weight is preferable.

In order to achieve the above object, 40 to 60 wt% of R1270 (propylene), 35 to 50 wt% of R134a (1,1,1,2-tetrafluoroethane) and R600a (isobutane) in a mixed refrigerant for refrigeration / air conditioner ) Is preferably composed of 1 to 10% by weight.

The above object of the present invention can also be achieved by a freezer / air conditioner using any of the above listed mixed refrigerants.

Other objects, specific advantages and novel features of the invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings.

Hereinafter, with reference to the accompanying drawings it will be described in detail with respect to the configuration of the mixed refrigerant for R502 and R22 and the refrigeration system using the same according to an embodiment of the present invention.

The present invention is composed of a material which can be used as a refrigerant (referred to as R) in a vapor compression refrigeration / air conditioner, namely, 'propylene, R134a, R152a, dimethyl ether (hereinafter referred to as DME) and isobutane. Mixed refrigerant and a refrigeration system using the same. More specifically, R502 (hereinafter referred to as CFC502), which has been widely used in low temperature freezers and transport freezers, and monochloro chloride, which has been widely used in domestic air conditioners and commercial air conditioners, A mixed refrigerant and refrigeration system can be substituted for fluoromethane (CHClF ₂ , hereinafter referred to as R22 or HCFC22).

The object of the present invention is that since the ODP is 0.0, it does not affect the ozone layer in the stratosphere at all, and the global warming index is also lower than that of other conventional refrigerants, and at the same time, it is an alternative refrigerant of CFC502 and HCFC22 without greatly modifying the existing compressor. It is to provide a mixed refrigerant and refrigeration system that can be used.

More specifically, the present invention relates to R1270 (propylene, propylene) and R134a (1,1,1,2-tetrafluoroethane) and R152a (1,1-difluoroethane) and RE170 (dimethyl ether, DME) and R600a. (Iso-butane, Iso-butane) relates to a mixed refrigerant and refrigeration system consisting of a selective combination. The alternative mixed refrigerant proposed in the present invention has an ozone depletion index (ODP) of 0.0 and a lower global warming index (GWP) than other alternative refrigerants, and the coefficient of performance (COP) and volume capacity (VC) of CFC502 or HCFC22. Yields a value close to

1 is a block diagram of a general refrigeration / air conditioner used in the present invention. As shown in FIG. 1, the refrigeration / air conditioner generally comprises an evaporator, a condenser, a compressor, an expansion valve, and the like.

To develop an alternative mixed refrigerant, the inventors used the CYCLE-D program developed by the National Institute of Standards and Technology, which simulates the performance of a refrigeration / air conditioner. The program conducted thermodynamic and heat transfer analyzes of the components that make up the refrigeration / air conditioner, such as heat exchangers and compressors, and finally used them all in combination. One of the important factors that determine the accuracy of the program is the properties of the refrigerant. In this program, the properties of all refrigerants were calculated using the Carnahan-Starling-De Santis (CSD) state equation, which is the standard in the United States and Japan. The CSD state equation, known as REFPROP, was developed by the National Institute of Standards and Technology and is the most widely used program in leading refrigeration and air conditioning companies, laboratories, and universities worldwide for its proven accuracy and applicability. The actual data was used as input data for the development and execution of the mixed refrigerant and refrigeration / air conditioner.

The inventors have determined that the ozone depletion index (ODP) of the alternative refrigerant for refrigeration / air conditioners must be 0.0 and the global warming potential (GWP) should be as low as possible. R1270 (propylene, propylene) and R134a (1,1,1,2 Tetrafluoroethane) and R152a (1,1-difluoroethane), RE170 (dimethyl ether, DME), and R600a (isobutane, Iso-butane) can be optionally combined to replace existing refrigerants. It was.

[Table 2] shows the results of comparing the performance index of the mixed refrigerant according to the present invention with the performance index of the existing refrigerant calculated by the computerized analysis program by applying the conditions of the refrigeration / air conditioner using the existing CFC502 , [Table 3] shows the results of comparing the performance index of the mixed refrigerant according to the present invention with the performance index of the conventional refrigerant calculated by the computerized analysis program applying the conditions of use of the refrigeration / air conditioner using the existing HCFC22 will be.

[Comparison of the Performance of CFC502 and Alternative Mixed Refrigerants] Refrigerant Composition (% by weight) COP VC (kJ / ㎥) GTD (℃) T _dis (℃) COP _diff (%) VC _diff (%) R1270 R134a R152a RE170 R600a CFC502 1.07 816 0.2 102.7 R404A 0.99 807 0.7 94.7 -7.5 -1.1 Inventive Example 1 30 40 30 1.34 805 8.1 117.0 25.2 -1.3 Inventive Example 2 40 40 20 1.32 880 5.2 114.1 23.4 7.8 Inventive Example 3 40 30 30 1.34 885 5.8 116.2 25.2 8.5 Inventive Example 4 70 10 20 1.24 972 0.7 108.1 15.9 19.1 Inventive Example 5 30 50 20 1.32 753 6.1 115.0 23.4 -7.7 Inventive Example 6 50 10 40 1.34 810 5.2 119.3 25.2 -0.7 Inventive Example 7 70 10 20 1.30 915 1.4 114.7 21.5 12.1 Inventive Example 8 30 60 10 1.30 794 4.6 103.8 21.5 -2.7 Inventive Example 9 40 50 10 1.30 841 4.1 104.8 21.5 3.1 Inventive Example 10 70 10 20 1.29 811 6.7 109.8 20.6 -0.6 Inventive Example 11 70 20 10 1.28 894 3.8 109.2 19.6 9.6

[Comparison of Performance of HCFC22 and Alternative Mixed Refrigerants] Refrigerant Composition (% by weight) COP VC (kJ / ㎥) GTD (℃) T _dis (℃) COP _diff (%) VC _diff (%) R1270 R134a R152a RE170 R600a HCFC22 2.88 3565 0.0 98.2 R407C 2.79 3776 6.9 90.6 -3.1 5.9 Inventive Example 12 40 40 20 2.83 3634 5.2 86.4 -1.7 1.9 Inventive Example 13 50 30 20 2.80 3739 3.0 86.0 -2.8 4.9 Inventive Example 14 60 10 30 2.81 3833 2.1 86.5 -2.4 7.5 Inventive Example 15 70 10 20 2.75 3824 0.7 85.8 --4.5 7.3 Inventive Example 16 50 20 30 2.87 3415 4.2 87.8 -0.3 -4.2 Inventive Example 17 80 10 10 2.71 3638 0.3 86.0 -5.9 2.0 Inventive Example 18 40 50 10 2.78 3474 4.1 82.6 -3.5 -2.6 Inventive Example 19 60 35 5 2.72 3623 2.1 84.0 -5.6 1.6

COP: coefficient of performance (Coefficient of performance, total refrigeration effect / day applied to the compressor)

VC: Volumetric capacity

GTD: Grading temperature difference

T _dis : Compressor discharge temperature

COP _diff : Performance factor difference compared to CFC502 (Table 2) and HCFC22 (Table 3)

VC _diff : Volume difference between CFC502 (Table 2) and HCFC22 (Table 3)

Tables 2 and 3 show that the refrigerants of Examples 1 to 19 of the present invention have higher or similar performance coefficients and similar volume capacities than conventional CFC502 or R404A or HCFC22 or R407C. In addition, since the temperature gradient of the mixed refrigerants is about 7 ° C. or less, which is the temperature gradient of the mixed refrigerants currently commercialized, there is no problem in using them. In addition, the compressor discharge temperature of the refrigerant examples 1 to 19 of the present invention is also similar to CFC502 or HCFC22, there is no problem to use.

Since all the refrigerants of Examples 1 to 19 of the present invention have an ozone depletion index (ODP) of 0.0 and do not destroy the ozone layer at all, they are much superior to CFC502 and HCFC22 in terms of environmental preservation. In the case of R404A or R407C, which are alternative refrigerants for CFC502 and HCFC22, they are regulated under the Kyoto Protocol due to their high global warming index. You can also reduce.

For reference, other compositions that deviate from the compositions of the present inventions described above, whether the temperature gradient is too large, the capacity and the efficiency are too low, or the compressor discharge temperature is too high, there is a problem in the actual application to the refrigeration / air conditioner, Look specifically.

[Inventive Examples 1, 2, 3, 4, 12, 13, 14, 15]

As shown in Examples 1, 2, 3, 4, 12, 13, 14, and 15, when R1270 is used within 30% by weight, the temperature gradient becomes too large and unsuitable, and when R1270 contains more than 70% by weight, the volumetric capacity is Too large and inappropriate As R134a increases, the volume capacity decreases. Therefore, in order to prevent the volume capacity from becoming too small, R134a is preferably included within 40% by weight. R152a is a substance having a lower vapor pressure than R1270 and R134a. If R152a is contained in an amount of 30 wt% or more, the volumetric capacity of the mixed refrigerant becomes too small and the temperature gradient becomes too large. As the proportion is high, the volumetric capacity is too large to be suitable.

[Inventive Examples 5, 6, 7]

As shown in Examples 5, 6 and 7 of the present invention, when R1270 is included in less than 30% by weight, the volume capacity becomes too small and the temperature gradient becomes too large. On the contrary, when R1270 is 70% by weight or more, the volume capacity becomes too large, which is not appropriate. If R134a is 50% by weight or more, or RE170 is 40% by weight or more, the volume capacity is too small, which is not preferable. Therefore, R134a is preferably contained in 50% by weight or less and RE170 in 40% by weight or less. In addition, as the ratio of RE170 and R134a decreases, the ratio of R1270 is increased, so that RE170 or R134a is preferably included in an amount of 20% by weight or more.

[Inventive Examples 8, 9, 10, 11]

As shown in Examples 8, 9, 10, and 11 of the present invention, when R1270 is 70% by weight or more, the volumetric capacity of the mixed refrigerant is too large. On the contrary, when R1270 is 30% by weight or less, the volumetric capacity is too small. R600a is a material with a very low vapor pressure, so if it is included in more than 20% by weight, the temperature gradient becomes too large and unsuitable.

[Inventive Examples 16 and 17]

As shown in Examples 16 and 17 of the present invention, if the ratio of R134a and RE170 becomes too large, the temperature gradient becomes too large and at the same time the volume capacity becomes too small. Therefore, the composition ratio of R134a and RE170 together is preferably 50% by weight or less. Particularly, as the volume of RE170 increases, the volumetric capacity decreases rapidly, and therefore RE170 preferably does not exceed 30% by weight.

[Inventive Examples 18 and 19]

As shown in Examples 18 and 19 of the present invention, since the temperature gradient is drastically reduced when R1270 is included in a small amount, R1270 should be included in an amount of 40% by weight or more. On the other hand, as R1270 increases, the coefficient of performance decreases, so that R1270 is preferably 60% by weight or less in order to maintain an appropriate coefficient of performance. If R600a is more than 10% by weight, the temperature gradient becomes too large and the volume capacity becomes too small, which is not appropriate.

According to the mixed refrigerant for R502 and R22 and the refrigeration system using the same according to the preferred embodiment of the present invention having the above-described configuration, the material constituting the mixed refrigerant is ozone layer destruction index of 0.0 and very low global warming index of propylene, 1, Since 1,1,2-tetrafluoroethane, 1,1-difluoroethane, dimethyl ether and isobutane are used, it is possible to prevent the destruction of the earth's ozone layer and global warming even when the refrigerant is leaked or discarded. There is a significant effect.

In addition, the mixed refrigerant according to the present invention is a mixture of propylene, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane, dimethyl ether and isobutane by mixing in a suitable composition vapor pressure or volumetric capacity of the mixed refrigerant Since it is similar to the existing refrigerant R502 or R22 refrigerant can be applied directly without replacing the compressor or modify the existing refrigeration system, there is an effect that the time and cost is reduced.

In the mixed refrigerant of the present invention, since the temperature gradient is very small by mixing the proper composition, there is almost no change in the refrigerant pressure due to the phase change of the refrigerant, so that the refrigeration system can be used stably, and the separation of the composition during the outflow of the refrigerant is prevented. It works.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

1 is a block diagram of a general refrigeration / air conditioner used in the present invention.

Explanation of symbols on the main parts of the drawings

Qc: direction of heat flow in 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

Evaporator: Compressor: Compressor

Condenser: Condenser, Expansion Valve: Expansion Valve

Claims (4)

30 to 70 wt% of R1270 (propylene), 1 to 69 wt% of R134a (1,1,1,2-tetrafluoroethane) and 1 to 69 wt% of R600a (isobutane) Composed of mixed refrigerant. The method of claim 1, 30 to 70 wt% of R1270 (propylene), 10 to 60 wt% of R134a (1,1,1,2-tetrafluoroethane) and 1 to 20 wt% of R600a (isobutane) Composed of mixed refrigerant. The method of claim 1, 40 to 60 wt% of R1270 (propylene), 35 to 50 wt% of R134a (1,1,1,2-tetrafluoroethane) and 1 to 10 wt% of R600a (isobutane) Composed of mixed refrigerant. delete