KR100540278B1 - R502 substitute mixed refrigerant and refrigeration system using thereof - Google Patents

Abstract

The present invention relates to a mixed refrigerant for replacing R502 used in a vapor compression refrigerator or an air conditioner and a refrigeration system using the same. More specifically, the present invention relates to a direct refrigerant without replacing the existing refrigeration system without causing ozone layer destruction and global warming. It relates to a mixed refrigerant composed of a combination of propylene, propane, pentafluoroethane and 1,1,1-trifluoroethane for application. The mixed refrigerant according to a preferred embodiment of the present invention is 1 to 98% by weight of R1270 (propylene), 1 to 98% by weight of R290 (propane) and 1 to 20% by weight of R143a (1,1,1-trifluoroethane). It is composed.

Description

R502 SUBSTITUTE MIXED REFRIGERANT AND REFRIGERATION SYSTEM USING THEREOF}

The present invention relates to a material that can be used as a refrigerant (referred to as R) in a vapor compression refrigeration / air conditioner, that is, a mixed refrigerant composed of a combination of propylene and propane and R125 and R143a and a refrigeration system using the same. Specifically, the present invention relates to a mixed refrigerant capable of replacing R502 (hereinafter referred to as CFC502) which has been widely applied to a low temperature freezer and a transport refrigerator. 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 most widely used in freezers, transport freezers, supermarket freezers, and the like. 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. CFC502 has a high Ozone Depletion Potential (ODP) of 0.18, which has now been decommissioned in developed countries under the Montreal Protocol, and most countries around the world now try to use alternative refrigerants with an ODP of 0.0. Doing.

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 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.

The present invention has been made to solve the above problems of the prior art, an object of the present invention is propylene, propane, pentafluoroethane and 1,1,1-trifluoro which are substances that do not cause ozone layer destruction and global warming By using ethane in combination at an appropriate composition ratio, it is to provide a mixed refrigerant and a refrigeration system using the same, which can be directly applied without replacing or remodeling an existing refrigeration system.

The above object of the present invention is a mixture consisting of 1 to 98% by weight of R1270 (propylene), 1 to 98% by weight of R290 (propane), and 1 to 30% by weight of R125 (pentafluoroethane) in a refrigeration / air conditioner mixed refrigerant. Achieved by the refrigerant.

In order to achieve the above object, 1 to 20% by weight of R1270 (propylene), 60 to 85% by weight of R290 (propane), and 1 to 30% by weight of R125 (pentafluoroethane) in a refrigeration / air conditioner mixed refrigerant It is preferable.

In addition, the object of the present invention described above is 1 to 98% by weight of R1270 (propylene), 1 to 98% by weight of R290 (propane) and R143a (1,1,1-trifluoroethane) in a refrigerant mixture for refrigeration / air conditioning It can also be achieved by a mixed refrigerant composed of 20% by weight.

In order to achieve the above object, R1270 is 1 to 20% by weight, R290 is 70 to 90% by weight and R143a is preferably 1 to 20% by weight.

The above object of the present invention can also be achieved by a refrigerating / 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 will be described in detail with respect to the configuration of the R502 replacement mixed refrigerant and a refrigeration system using the same according to an embodiment of the present invention.

The present invention relates to a material that can be used as a refrigerant (referred to as R) in a vapor compression refrigeration / air conditioner, that is, a mixed refrigerant composed of a combination of propylene and propane and R125 and R143a and a refrigeration system using the same. Specifically, the present invention relates to a mixed refrigerant capable of replacing R502 (hereinafter referred to as CFC502) which has been widely applied to a low temperature freezer and a transport refrigerator.

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 other alternative refrigerants and at the same time, it can be used as an alternative refrigerant of CFC502 without greatly modifying the existing compressor. To provide a mixed refrigerant.

More specifically, the present invention relates to a mixed refrigerant composed of one of R1270 (propylene, propylene) and R290 (propane, propane) and R125 (pentafluoroethane) and R143a (1,1,1-trifluoroethane). 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 is close to the coefficient of performance (COP) and volume capacity (VC) of CFC502. Yields a value.

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 present inventors have determined that the ozone depletion index (ODP) of the alternative refrigerant for refrigeration / air conditioner should be 0.0 and the global warming potential (GWP) should be as low as possible. Therefore, natural refrigerants R1270 (propylene, propylene) and R290 (propane, propane) In addition, R125 (pentafluoroethane) and R143a (1,1,1-trifluoroethane) were mixed to replace the existing refrigerant.

[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 conventional refrigerant calculated by the computerized analysis program by applying the conditions of the refrigeration / air conditioner using the existing CFC502 .

[Performance Comparison of CFC502 and Alternative Mixed Refrigerants] Refrigerant Composition (% by weight) COP VC (kJ / m ³ ) GTD (℃) Tdis (℃) COP _diff (%) VC _diff (%) R1270 R290 R125 R143a CFC502 1.07 816 0.2 102.7 R404A 0.99 807 0.7 94.7 -7.5 -1.1 Inventive Example 1 10 60 30 1.18 879 6.5 98.9 10.3 7.7 Inventive Example 2 10 85 5 1.18 784 2.2 101.8 10.3 -3.9 Inventive Example 3 20 70 10 1.19 842 3.1 102.1 11.2 3.2 Inventive Example 4 10 70 20 1.23 927 1.9 101.5 15.0 13.6 Inventive Example 5 10 85 5 1.19 805 0.9 102.1 11.2 -1.3 Inventive Example 6 20 70 10 1.22 884 1.3 102.8 14.0 8.3

* COP: Coefficient of performance (total refrigeration effect / work done on the compressor)

* VC: Volumetric capacity

* GTD: Grading temperature difference

* T _dis : Compressor discharge temperature

* COP _diff : Performance factor difference compared to CFC502

* VC _diff : Volumetric difference compared to CFC502

Table 2 shows that the mixed refrigerants of Examples 1 to 6 of the present invention have higher performance coefficients and similar volume capacities than conventional CFC502 or R404A. Considering that the temperature gradient of various mixed refrigerants currently commercialized is less than 7 ° C., the temperature gradient of these mixed refrigerants is less than that, so there is no problem in using them. In addition, the compressor discharge temperature of the mixed refrigerants of Examples 1 to 6 of the present invention is also similar to CFC502, so there is no problem to use.

All mixed refrigerants of Examples 1 to 6 of the present invention are much better than CFC502 in terms of environmental preservation because the ozone depletion index (ODP) is 0.0 and does not destroy the ozone layer at all. In addition, R404A, an alternative to CFC502, is regulated under the Kyoto Protocol due to its high global warming index. Therefore, the use of mixed refrigerants based on propylene and propane can reduce HFC usage and reduce global warming.

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]

As shown in Examples 1, 2, and 3 of the present invention, when the ratio of R125 in the mixed refrigerant increases, the temperature gradient increases, which is not appropriate. Therefore, R125 is preferably 30% by weight or less. As R1270 increases, the volume capacity tends to increase. Therefore, in order for the mixed refrigerant to have a volume capacity similar to that of the existing refrigerant, it is preferable that R1270 does not exceed 20% by weight. As shown in Examples 1 and 2 of the present invention, when R290 increases, the volumetric capacity of the mixed refrigerant decreases, so that R290 is preferably in the range of 60 to 85% by weight in order for the mixed refrigerant to have an appropriate volumetric capacity.

That is, in the mixed refrigerant, R125 should be 30 wt% or less, so that the temperature gradient can be 6.5 or less. In particular, when 10 wt% or less, the temperature gradient does not exceed 3 degrees. In addition, since R1270 has a higher vapor pressure than R290, when R1270 is 1 to 20% by weight and R290 is 60 to 85% by weight, the volumetric capacity of the existing refrigerant is similar.

[Inventive Examples 4, 5, 6]

As shown in Examples 4, 5 and 6 of the present invention, when the ratio of R143a in the mixed refrigerant exceeds 20% by weight, the volumetric capacity is larger than that of the existing refrigerant, and thus the compressor needs to be replaced. Therefore, R143a is preferably 20% by weight or less. When the composition ratio of 1270 in Examples 4 and 5 of the present invention is constant, the ratio of R143a increased from 5% by weight to 20% by weight was also confirmed that the volumetric capacity increased from 805 to 927. In addition, when the composition ratio of R290 is constant in Examples 4 and 6 of the present invention, it is also confirmed that the volume capacity is increased from 884 to 927 when the ratio of R143a is increased from 10% by weight to 20% by weight.

As shown in Examples 5 and 6 of the present invention, when the ratio of R1270 is increased from 10% to 20% by weight in a state where the ratio of R143a is almost the same in the mixed refrigerant, the volumetric capacity increases from 805 to 884, so that the increase in R1270 is the volumetric capacity. Brings an increase. Therefore, the composition ratio of R1270 should not exceed 20% by weight so that the volumetric capacity of the mixed refrigerant is similar to that of the existing refrigerant.

It is to be noted that the term "refrigeration system" used throughout the specification of the present invention is used in the meaning of a refrigerator / air conditioner, unless otherwise specified, that both are used in the same meaning.

According to a mixed refrigerant for R502 and a refrigeration system using the same according to a preferred embodiment of the present invention having the above-described configuration, propylene, propane and pentafluor as a material constituting the mixed refrigerant have an ozone depletion index of 0.0 and a very small global warming index. Because of the use of loethane and 1,1,1-trifluoroethane, there is a remarkable effect of preventing the global ozone layer destruction and global warming even when the refrigerant is leaked or disposed of.

In addition, the mixed refrigerant according to the present invention is a mixture of propylene, propane, pentafluoroethane and 1,1,1-trifluoroethane in an appropriate composition by mixing the refrigerant and the vapor pressure or volumetric capacity of the refrigerant refrigerant R502 refrigerant Since it is similar, it can be applied directly without replacing the compressor or modifying the existing refrigeration system, thereby reducing the time and economic cost.

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 (3)

Mixed refrigerant for refrigeration / air conditioner consisting of 1 to 98% by weight of R1270 (propylene), 1 to 98% by weight of R290 (propane) and 1 to 20% by weight of R143a (1,1,1-trifluoroethane) . The method of claim 1, R1270 is 1 to 20% by weight, R290 is 70 to 90% by weight and R143a is a mixed refrigerant, characterized in that 1 to 20% by weight. delete