KR20150116470A - Ternary refrigerant mixture composed of R32, RC270, R1234ze - Google Patents

Abstract

The present invention relates to a mixed refrigerant comprised of materials including R_32, RC_270, and R_1234_ze, which can be used as a refrigerant (referred to as R) vapor compression-type refrigerating air conditioner. More specifically, the present invention relates to a ternary mixed refrigerant, which can substitute monochlorodifluoromethane (CHClF_2, referred to as R_22 or HCFC_22) which has been widely used in a domestic air conditioner or in a commercial refrigerating air conditioner so far.

Description

(R32, RC270, R1234ze) composed of R32, RC270 and R1234ze (Ternary refrigerant mixture composed of R32, RC270 and R1234ze)

The present invention relates to a mixed refrigerant composed of materials which can be used as a refrigerant (hereinafter referred to as R) in a vapor compression type refrigerator / air conditioner, that is, "R32 and RC270 and R1234ze", and more specifically, (CHClF2, hereinafter referred to as " R22 " or " HCFC22 ") widely used in air conditioners and the like.

Until now, chlorofluorocarbon (hereinafter referred to as CFC) and hydrofluorofluorocarbon (HCFC) derived from methane or ethane have been mainly used as refrigerants for refrigerators, air conditioners and heat pumps, , Commercial air conditioners, etc., R22 with a boiling point of -40.8 ° C and a molecular mass of 86.47 kg / kmol has been the most widely used.

In recent years, however, the collapse of the stratospheric ozone layer by CFCs and HCFCs has become an important global environmental issue, and the production and consumption of CFCs and HCFCs, which disrupt stratospheric ozone, are regulated by the Montreal Protocol, As shown in Table 1, which shows the environmental index of several refrigerants, HCFC22 has a high ozone depletion potential (ODP) of 0.05, which is currently fully developed in developed countries based on the Montreal Protocol, Countries must now use alternative refrigerants with an ozone depletion potential (ODP) of 0.0.

Refrigerant Ozone layer decay index
(ODP) Global Warming Index
(GWP) HCFC22 0.05 1,790 HFC32 0.00 716 HFC134a 0.00 1,370 R407C 0.00 1,610 R410A 0.00 2,068

(*) ODP is based on CFC11 set at 1.0.

(**) GWP is based on the assumption that carbon dioxide in the 100th year is 1.0.

In recent years, not only the problem of ozone layer collapse but also the problem of global warming has started to grow rapidly, and the Kyoto Protocol of 1997 strongly recommends that global warming potential (GWP) refrain from using high refrigerant . Reflecting this trend, companies producing household air conditioners and heat pumps in Europe and Japan are trying to develop and use refrigerants with a low global warming index (GWP).

For a substance to be useful as an alternative refrigerant for existing refrigerants, it should first have a coefficient of performance (COP) similar to that of conventional refrigerants. Here, the coefficient of performance (COP) means the total refrigeration effect as compared with the work done to the compressor. The larger the COP, the better the energy efficiency of the refrigerator / air conditioner.

Also, if the compressor is to be used without major modifications, the alternative refrigerant must have a vapor pressure similar to that of conventional refrigerants and ultimately provide a similar volumetric capacity (VC). Here, the volume capacity (VC) means the refrigerating effect per unit volume, which is a factor indicating the size of the compressor, which is usually proportional to the vapor pressure and the unit is kJ / m ³ . If the alternative refrigerant has a volume capacity similar to that of conventional refrigerants, it is very advantageous for the manufacturer to make a refrigeration / air conditioner without changing the compressor or making major modifications, which is usually called drop-in replacement. However, as a result of research to date, it has been found that when replacing existing refrigerant with pure water, the volume capacity of alternative refrigerant is different and it is inevitably necessary to change or largely change the compressor or to make a performance coefficient similar to that of existing refrigerant.

One way to solve this problem is to use mixed refrigerants. The characteristics of the mixed refrigerant are such that the composition is well compounded to make the coefficient of performance close to that of conventional refrigerants, while at the same time providing a volume capacity (VC) similar to that of conventional refrigerants, thereby eliminating the need for major retrofit of the compressor through drop-in replacement. Because of this nature, several mixed refrigerants have been proposed as alternatives to HCFC22 in the past few years, but some of them have HCFC as a constituent in the Montreal Protocol and are not suitable alternatives in the long run.

The R407C refrigerant (23% R32 / 25% R125 / 52% R134a), developed by DuPont in the US, is similar in refrigerating capacity to conventional HCFC22, but has low energy efficiency and has a global warming index Is almost similar to HCFC22.

On the other hand, Honeywell has developed and sold a binary mixed refrigerant (50% R32 / 50% R125) called R410A, but the refrigerant needs to change the compressor because the vapor pressure is 60% higher than the conventional HCFC22. In addition, as shown in Table 1, R410A has an ozone depletion index of 0.0, but the global warming index is larger than R22, raising doubts as to whether it will continue to be used in the long term.

Korean Patent No. 10-0335249 entitled " hydrocarbon-based nonflammable refrigerant composition and its production method " is known as a conventional technology relating to a mixed refrigerant for reducing global warming.

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and an object of the present invention is to provide an ozone depletion index (ODP) of 0.0, which has no influence on the ozone layer in the stratosphere, The present invention relates to a three-component mixed refrigerant composed of R32, RC270 and R1234ze which can be used as an alternative refrigerant for HCFC22 while using conventional compressors and heat exchangers intact.

It is an object of the present invention to provide a process for producing a polyimide resin, which comprises 40 to 50% by weight of R32, 1 to 5% by weight of RC270, 49 to 59% by weight of R1234ze and sum of R32, RC270 and R1234ze Is 100% by weight based on the total weight of the refrigerant mixture. The refrigerant mixture is composed of R32, RC270 and R1234ze, and a refrigeration air conditioner using the refrigerant.

According to the ternary mixed refrigerant according to the present invention, the ozone layer decomposition index (ODP) is 0.0, which has no effect on the ozone layer in the stratosphere, and the global warming index is much lower than that of conventional refrigerants. At the same time, It is possible to use the refrigerant as an alternative refrigerant.

1 is a configuration diagram of a refrigerator / air conditioner used in the present invention.
FIG. 2 is a graph showing the temperature gradients of the three-way mixed refrigerant composed of R32, RC270, and R1234ze by contour lines.

Hereinafter, the construction of a three-way mixed refrigerant composed of R32, RC270, and R1234ze according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Since the ODP (Ozone Depletion Potential) of the present invention is 0.0, the present invention has no influence on the ozone layer in the stratosphere, and the global warming index is much lower than that of the existing refrigerant, and can be used as an alternative refrigerant of HCFC22 while using conventional compressors and heat exchangers And more particularly to a ternary mixed refrigerant composed of R32, RC270 and R1234ze.

The core of the present invention is a combination of R32, which is relatively low in global warming index, and RC270, which is close to zero, and R1234ze, which is good in performance and material compatibility, so that ozone depletion index is 0.0 and global warming index is lower than that of existing R22. Development.

In order to develop an alternative mixed refrigerant, the inventor used a program that simulates the performance of the refrigerator / air conditioner. 1 is a schematic view of a general refrigerator / air conditioner used in the present invention, which comprises an evaporator, a condenser, a compressor, an expansion valve, and the like. This program is a refrigeration cycle analysis program called Cycle-D developed by the National Institute of Standards and Technology. This is a proven program widely used by leading companies, universities, and research institutes around the world.

One of the important factors determining the accuracy of this program is the properties of the refrigerant. In this program, the REFPROP program, which is the standard in USA, Japan and EU, was used to calculate the properties of all refrigerants. The REFPROP program was developed by the American National Standards Institute and has proved its accuracy and applicability, making it the most widely used in leading companies, research institutes and universities worldwide. The program and material used here are the latest models with the most recent data.

The inventors have found that the ODP of the alternative refrigerant for the refrigerator / air conditioner must be 0.0 and that the GWP should be as low as possible and that the ODP is 0.0 and that GWP is relatively low compared to other refrigerants RC270 and R1234ze can be mixed to replace the existing R22.

Table 2 summarizes the results of comparing the performance of the R32 / RC270 / R1234ze mixed refrigerant for R22 substitution calculated using the computational analysis program under the existing refrigerator / air conditioner operating conditions. 3 shows the performance index of mixed refrigerant.

The results in Table 2 are calculated under the same freezing capacity of 3.5 kW (the condition of the evaporator refrigerant is 7 ° C and the temperature of the condenser refrigerant is 45 ° C as the air conditioner driving condition).

Refrigerant Composition (% by weight) VC VC diff (%) COPc COP diff (%) Work (W) Tdis (占 폚) GTD
(° C) GWP R32 RC270 R1234ze R22 3883 3.969 882 83 1790 One 40 One 59 4048 4 3.851 -3.0 909 82 10.0 274 2 45 5 50 4359 12 3.816 -3.9 917 85 10.0 307 3 45 3 52 4327 11 3.823 -3.7 916 84 9.5 307 4 45 2 53 4293 11 3.827 -3.6 915 84 9.2 307 5 50 One 49 4466 15 3.816 -3.9 917 85 7.9 340

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

COP _diff : Difference in performance coefficient compared to R22

  W : Compressor work

  Tdis : Compressor discharge temperature

  GTD : Temperature glide

GWP: Global warming potential (Global warming potential)

As mentioned above, the most important thing for the manufacturer is to replace the refrigerant without replacing the compressor or making a major modification, and to achieve a replacement, drop-in replacement. In order to achieve this drop-in replacement, the volume capacity (VC) of the alternative refrigerant must be similar to the volume capacity of the existing R22.

Table 2 shows the volume capacity (VC) and coefficient of performance (COP) of the three-way mixed refrigerant under the same freezing capacity. Meanwhile, FIG. 2 shows the temperature gradient of the R32 / RC270 / R1234ze three-component mixed refrigerant according to the present invention on a triangular diagram using contour lines. Even if the performance of the mixed refrigerant is good, if the temperature gradient becomes 10 ° C or more, it is difficult to use the refrigerant / air conditioner because the separation phenomenon becomes serious when leaking. As can be seen from Table 2, when the composition of R32 is 40 to 50 wt%, the composition of RC270 is 1 to 5 wt%, and the composition of R1234ze is 49 to 59 wt%, the temperature gradient of the tertiary mixed refrigerant is 10 ℃ and volume capacity is about 10% higher or lower than R22. Therefore, in this composition range, the R22 can be drop-in replaced with the three-way mixed refrigerant of Table 2, without modifying the compressor size for R22.

In the composition range shown in Table 2, the performance coefficient of the mixed refrigerant of the present invention is reduced by 4.9% at maximum compared to the conventional R22. However, this level of difference can be made much like the existing system through optimization of the system. R410A, which is currently used as an alternative refrigerant for HCFC22, is estimated to be 6.8% lower than that of HCFC22 under the same conditions. However, the coefficient of performance of the air conditioner charged with R410A actually increases by more than 5% compared with the conventional HCFC22 system. This is because the system has been optimized. Therefore, the mixed refrigerant shown in Table 2 is expected to achieve the performance of the conventional HCFC22 through optimization of the system.

On the other hand, the temperature gradient (GTD) of the present mixed refrigerant in the composition range of Table 2 is less than 10 ° C. which is the temperature gradient of the currently mixed refrigerant, for example, R407C - There will be no problem. In the future, it seems that water-cooled type refrigerator or heat pump will be widely used. In this case, this temperature gradient will be a great help to improve system performance.

Compressor discharge temperature of the present mixed refrigerant is lower than R22 in the composition range of Table 2, and it is considered that it will not affect system reliability.

In other compositions, it is not possible to achieve the drop-in replacement of the present invention because the capacity is not suitable or the temperature gradient must be largely modified or changed in the same refrigerator / air conditioner compressor using R22.

Finally, the global warming potential (GWP) of this mixed refrigerant is 274 ~ 340 in the composition range of Table 2, which is a low value of 15.3 ~ 19.0% compared with the conventional R22. Therefore, this mixed refrigerant does not cause the ozone layer collapse, and the global warming index is much lower than that of conventional refrigerant, so that it can be used as an environmentally friendly refrigerant in the long term.

Qcond: Heat flow direction in the condenser (refrigerant air)
Qevap: Direction of heat flow in the evaporator (air refrigerant)
TS1: Evaporator air inlet temperature, TS7: Evaporator air outlet temperature
TS3: Condenser air outlet temperature, TS6: Condenser air inlet temperature
Evaporator: Evaporator, Compressor: Compressor
Condenser: Condenser, Expansion Valve: Inflator

Claims (2)

Wherein the composition of R32 is 40 to 50 wt%, the composition of RC270 is 1 to 5 wt%, the composition of R1234ze is 49 to 59 wt%, the sum of R32, RC270 and R1234ze is 100 wt% R32, RC270, and R1234ze. A refrigeration / air conditioner using the three-way mixed refrigerant according to claim 1.

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