RU2241729C2 - Refrigerant replacing r 22 - Google Patents

Abstract

FIELD: refrigerating agents.

SUBSTANCE: invention relates to a refrigerant, used in particular, for air conditioning. The composition of refrigerant involves fluorohydrocarbon component comprising 1,1,1,2-tetrafluoroethane (R 134a) and pentafluoroethane (R 125). The composition involves additionally additive taken among the group involving saturated hydrocarbon or their mixture boiling in the range of temperatures from -5^oC to +70^oC. Invention involves a diluting agent for refrigerant and a method for modifying the refrigerating system or the air conditioning system comprising R 22 as a refrigerant. Proposed compositions don't comprise chlorine atoms and don't exert harmful effect on ozone layer.

EFFECT: improved and valuable properties of agent.

18 cl, 8 tbl, 3 dwg, 7 ex

Description

This invention relates to a refrigerant, in particular (but not exclusively) for air conditioning systems. This system, in particular, relates to compositions of refrigerants that do not adversely affect the ozone layer in the atmosphere, and to compositions that can be added to existing refrigerants that are compatible with lubricants commonly used in refrigeration and air conditioning systems. The present invention also relates to a method for modifying cooling and air conditioning systems.

Chlorofluorocarbons (CFC), such as CFC-11 and CFC-12, are stable, have low toxicity and are non-flammable, which provides a low level of danger when used in cooling and air conditioning systems. When ejected, they penetrate the stratosphere and destroy the ozone layer, which protects the environment from the harmful effects of ultraviolet rays. The Montreal Protocol, an international environmental agreement signed by more than 160 countries, prescribes the gradual phasing out of CFC on schedule. Now this also applies to chlorofluorocarbons (HCFCs), which also have a harmful effect on the ozone layer.

R22 is a chemical fluid and by far the most widely used refrigerant in the world of HCFC for refrigeration and air conditioning systems. R22 has a certain ozone depletion potential of approximately 5% of this value for CFC11. Once the use of chlorofluorocarbons (CFC) has been ruled out, the chlorine content of R22 can make it the largest (by volume) ozone-depleting substance. R22 is also subject to the Montreal Protocol cessation program. In some countries, R22 is prohibited for use in new equipment.

Any replacement for HCFC 22 should include a lack of ability to deplete the ozone layer. The compositions of this invention do not contain chlorine atoms and, therefore, they will not have a harmful effect on the ozone layer, while at the same time providing behavior similar to the behavior of R22 as a working fluid in refrigeration units.

Various terms are used in the patent literature to describe mixtures of refrigerants. Among them are the following:

Zeotrop: a mixture of liquids in which the composition of the liquid and vapor phases at a given temperature is different.

Temperature shift: if a mixture of liquids, in which the composition of the liquid and vapor phases at a given temperature is different, is distilled at constant pressure, its boiling point will increase. The change in boiling point from the beginning of the distillation to the point of disappearance of the liquid phase is called the temperature shift. A shift is also observed when the saturated vapor of such a mixture condenses at constant pressure.

Azeotrope: a mixture of liquids of a certain composition, in which at a certain temperature the composition of vapor and liquid is the same. Strictly speaking, a mixture of liquids, which is an azeotrope, for example, in an evaporator, cannot also be an azeotrope in a condenser. However, literature on refrigeration can describe a mixture as azeotropic if it meets the above definition at a certain temperature within the operating range.

A mixture close to the azeotrope: a mixture that boils in a small temperature range, that is, has a small temperature shift.

Mixture - refrigerant modifier: a chlorine-free mixture used to completely replace the original CFC or HCFC refrigerant.

Mixture - refrigerant diluent: A chlorine-free mixture added during servicing to the refrigerant remaining in the HCFC unit, i.e. replenishing refrigerant, to compensate for leakage.

Sealed Compressor: A compressor in which the electric motor is located in the same completely sealed enclosure as the compressor. The engine is cooled by refrigerant vapor returning to the compressor. The heat generated by the engine is removed through a condenser.

Semi-hermetic compressor: similar to a hermetic compressor; the main difference is that the housing has a bolted connection that can be disconnected so that the engine and compressor can be serviced.

Open compressor: a compressor that is driven by an external motor through a drive shaft passing through the compressor housing. Heat from the engine is dissipated directly into the environment, not through a condenser. This leads to a slightly more efficient operation than a hermetic compressor, but this may cause the refrigerant to leak on the shaft seal.

The percentages and ratios given in this description are mass, unless otherwise indicated. Percentages and ratios give a total of 100%. Refrigerants - HFC and HCFC compounds are indicated below by the letter R.

According to a first aspect of the invention, the composition of the refrigerant comprises 1,1,1,2-tetrafluoroethane (R 134a), pentafluoroethane (R125) and an additive selected from the group consisting of a saturated hydrocarbon or mixture thereof, boiling in the range from -5 to +70 ° C; moreover, the mass ratios of R125 and R134a are in the ranges:

R125 50-80%

R134a 50-20%

These compositions can be used as mixtures - modifiers of refrigerants. These compositions can also be used as diluents, as described below. These compositions can be used in semi-hermetic and sealed systems.

Preferred mass ratios of R125 and R134a are in the ranges:

R125 60-80%

R134a 40-20%

A more preferred range is:

R125 60-78%

R134a 40-22%

The most preferred range is:

R125 64-76%

R134a 34-24%

These ranges are preferred for sealed and semi-hermetic systems. These compositions can also be used in open systems. Preferred contents in an open system are in the ranges:

R125 57-78%

R134a 43-22%

A more preferred range is:

R125 63-76%

R134a 33-24%

The content of R125 used in an open system can be 10%, preferably 4-5%, higher than in a sealed or semi-hermetic system.

In a first aspect of the invention, no other refrigerant may be included in the mixture. In a second aspect suitable for use as a diluent for R22, additional R32 refrigerant may be added.

Preferred hydrocarbon additives are selected from the group consisting of 2-methylpropane, 2,2-dimethylpropane, butane, pentane, 2-methylbutane, cyclopentane, hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane and methylcyclopentane. This hydrocarbon additive preferably has a boiling point in the range of 20 to 40 ° C. The use of n-pentane, cyclopentane, isopentane and mixtures thereof is preferred. Particularly preferred is the use of n-pentane, isopentane or mixtures thereof. Among commercially available saturated hydrocarbon mixtures, commercial grade cyclopentane from Phillips Petroleum Internftional NV, n-pentane Norpar ^P 5 S from Exxon Chemical, and isopentane Q1111 from Shell Chemicals are available.

The relative proportions of the pentane and butane components can be selected so that in total they comprise from 0.2 to 5% of the composition, preferably from 2 to 4%, more preferably from 3 to 4%. You can choose the amount of pentane, preferably isopentane, from 0.2 to 2% together with the corresponding amount from 4.8 to 3% butane in a composition containing only 5% hydrocarbons. In formulations containing less than 5% hydrocarbons, for example 1 or 4%, relatively large butane: pentane ratios can be used to minimize the need for hydrocarbon replenishment in the event of a leak. This reduces the risk of ignition.

In a second aspect of the invention, the refrigerant diluent mixture comprises the composition of the first aspect of the invention.

According to a third aspect of the invention, the refrigerant comprises the composition of the first aspect of the invention in conjunction with R22. This invention also provides a method for modifying a refrigeration unit or an air conditioning system containing R22 as a refrigerant, the method comprising the step of adding the composition of the second aspect of the present invention to the refrigerant of the system.

Piston type compressors, that is, reciprocating or rotary compressors used in cooling systems, draw small amounts of grease from the crankcase that is discharged with refrigerant vapor through the exhaust valves. To preserve compressor lubrication, this oil should be directed along the circuit with a stream of refrigerant and returned to the crankcase. CFC and HCFC refrigerants mix with hydrocarbon lubricants and therefore transfer these lubricants along the circuit. However, HFC refrigerants and hydrocarbon lubricants have low mutual solubilities, therefore, an effective oil return cannot occur. This problem is especially acute in evaporators, where low temperatures can sufficiently increase the viscosity of oils to protect them from entrainment along the walls of the pipes. In the case of CFC and HCFC, a sufficient amount of refrigerant remains in the oil to reduce viscosity and allow oil return.

When using HFC with hydrocarbon lubricants, oil recovery can be facilitated by introducing a hydrocarbon fluid having the following properties into the system:

a) sufficient solubility in the lubricant at the evaporator temperature to reduce its viscosity;

c) sufficient volatility to allow distillation from the hot lubricant in the compressor crankcase.

Hydrocarbons meet these requirements.

The refrigerant compositions of this invention have several advantages. R125 has fire protection characteristics. The presence of R125 reduces the flammability of the refrigerant mixture. A higher content of HFC makes it possible to add more n-pentane to the mixture, thereby improving the solubility of the mixture with traditional lubricants, such as mineral and alkylbenzene oils.

The present invention can provide several advantages over R22, including zero ozone depletion, lower discharge temperature, and higher productivity.

This invention can provide several advantages over HFC replacement R407C, including better return of hydrocarbon grease, better cooling of the engine in a hermetic compressor, lower discharge temperature and lower discharge pressure.

The invention is further described by way of examples, which in no way have a restrictive meaning.

EXAMPLE 1

The behavior of the five P125 / P134a / pentane formulations was investigated using standard refrigeration cycle analysis techniques to assess their applicability as substitutes for R22 in sealed or semi-hermetic systems. The operating conditions used for the analysis were chosen so that they were typical of the conditions in air conditioning systems. Since in these mixtures the composition of the liquid and vapor phases at a given temperature is different, the average points of their temperature displacements in the evaporator and condenser were chosen to determine the temperature boundaries of the cycle. The same temperatures were used to obtain data on the behavior of R22.

Pentane was present in an amount of 4 wt.% Based on the total weight of the mixture R125 / R134a. To simplify the calculation, this small amount of pentane was not taken into account.

The following compositions of refrigerants were subjected to cycle analysis:

1. Composition comprising 44% R125: 56% R134a

2. Composition comprising 56% R125: 44% R134a

3. Composition comprising 64% R125: 36% R134a

4. Composition comprising 76% R125: 24% R134a

5. Composition comprising 80% R125: 20% R134a

The following cycle conditions were used for analysis:

Cooling capacity 10 kW

EVAPORATOR

The average temperature of evaporation of the liquid 7 ° C

Superheat 5.0 ° С

Pressure drop in the suction pipe (in units of saturation temperature) 1.5 ° С

CAPACITOR

The average temperature of liquid condensation 45 ° C

Subcooling 5.0 ° C

Pressure drop in the discharge pipe (in units of saturation temperature) 1.5 ° С

HEAT EXCHANGER LIQUID PIPELINE / SUCTION PIPELINE

Efficiency 0.3

COMPRESSOR

Motor efficiency 0.85

Isentropic compressor efficiency 0.7

Compressor Flow Rate 0.82

PARASITIC POWER

Inlet fan 0.3 kW

0.4 kW fan

Monitoring devices 0.1 kW

The results of the behavior analysis in the air conditioning unit using these operating conditions are shown in Table 1. The behavior of R22 is also shown for comparison.

All formulations have lower discharge temperatures than R22, and are therefore better in this regard. However, composition 5 is not preferred since the discharge pressure is more than 0.2 MPa (2 bar) higher than that of R22. Composition 1 is unacceptable because the cooling capacity is less than 90% of this value for R22. In general, the behavior of formulations 2, 3, and 4 satisfies the criteria set forth above and, therefore, satisfies the requirements of the present invention.

EXAMPLE 2

The behavior of the five P125 / P134a / pentane formulations was tested using standard chiller cycle analysis techniques to assess their suitability for replacing R22 in open systems. As the working conditions for the analysis, the conditions typical for air conditioning systems were selected. Since in these mixtures the composition of the liquid and vapor phases at a given temperature is different, the average points of their temperature displacements in the evaporator and in the condenser were chosen to determine the temperature boundaries of the cycle. The same temperatures were used to obtain data on the behavior of R22.

Pentane was present at a concentration of 4 wt.% Based on the total weight of the mixture R125 / R134a. To simplify the calculation, this small amount of pentane was not taken into account.

A cycle analysis was performed for the following refrigerant formulations:

1. Composition comprising 44% R125: 56% R134a

2. Composition comprising 56% R125: 44% R134a

3. Composition comprising 64% R125: 36% R134a

4. Composition comprising 76% R125: 24% R134a

5. Composition comprising 80% R125: 20% R134a

In the analysis, the following cycle parameters were used:

Cooling capacity 10 kW

EVAPORATOR

The average temperature of evaporation of the liquid 7.0 ° C

Superheat 5.0 ° С

Pressure drop in the suction pipe (in units of saturation temperature) 1.5 ° С

CAPACITOR

The average liquid condensation temperature of 45.0 ° C

Subcooling 5.0 ° C

Pressure drop in the discharge pipe (in units of saturation temperature) 1.5 ° С

HEAT EXCHANGER LIQUID PIPELINE / SUCTION PIPELINE

Efficiency 0.3

COMPRESSOR

Motor efficiency 0.85

Isentropic compressor efficiency 0.7

Compressor Flow Rate 0.82

PARASITIC POWER

0.3 kW internal fan

External fan 0.4 kW

Monitoring devices 0.1 kW

The results of the analysis of the behavior in the air conditioning unit when using these operating conditions are given in table 2. For comparison, the behavior for R22 is also given.

All formulations have lower discharge temperatures than R22, and therefore are better from this point of view. However, composition 5 is unacceptable, since its discharge pressure exceeds this value for R22 by more than 0.2 MPa (2 bar). Compounds 1 and 2 are unacceptable because their refrigerating capacity is less than 90% of the refrigerating capacity of R22. The behavior of formulations 3 and 4 generally satisfies the criteria set forth above, and, therefore, satisfy the requirements of this invention.

EXAMPLE 3

The behavior of the five P125 / P134a / pentane formulations was tested using standard chiller cycle analysis techniques to evaluate their ability to replace R22 in sealed or semi-hermetic systems without a liquid / suction pipe heat exchanger. Typical conditions for air conditioning systems were taken as the operating conditions used in the analysis. Since the composition of the liquid and vapor phases for these mixtures is different at a given temperature, the midpoints of the temperature shift intervals in the evaporator and condenser were chosen to determine the temperature boundaries of the cycle. The same temperatures were used to obtain data on the behavior of R22.

Pentane was present in an amount of 4 wt.% Based on the total weight of the mixture R125 / R134a. To simplify the calculations, this small amount of pentane was not taken into account.

A cycle analysis was performed for the following refrigerant formulations:

1. Composition comprising 44% R125: 56% R134a

2. Composition comprising 56% R125: 44% R134a

3. Composition comprising 64% R125: 36% R134a

4. Composition comprising 76% R125: 24% R134a

5. Composition comprising 80% R125: 20% R134a

In the analysis, the following cycle parameters were used:

Cooling capacity 10 kW

EVAPORATOR

The average temperature of evaporation of the liquid 7.0 ° C

Superheat 5.0 ° С

Pressure drop in the suction pipe (in units of saturation temperature) 1.5 ° С

CAPACITOR

The average liquid condensation temperature of 45.0 ° C

Subcooling 5.0 ° C

Pressure drop in the discharge pipe (in units of saturation temperature) 1.5 ° С

COMPRESSOR

Motor efficiency 0.85

Isentropic compressor efficiency 0.7

Compressor Flow Rate 0.82

PARASITIC POWER

0.47 kW internal fan

External fan 0.26 kW

Monitoring devices 0.1 kW

The results of the behavior analysis in the air conditioning unit using these operating conditions are shown in Table 3. For comparison, the behavior of R22 is also given.

All formulations have lower discharge temperatures than R22, and, therefore, it is better in this regard. However, composition 5 is unacceptable, since its discharge pressure is more than 0.2 MPa (2 bar) higher than this value for R22. Compounds 1 and 2 are unacceptable, since their refrigerating capacity is less than 90% of the refrigerating capacity of R22. The behavior of formulations 3 and 4 generally meets the criteria set above and, therefore, satisfies the requirements of this invention.

EXAMPLE 4

The behavior of the two R125 / R134a / pentane formulations was investigated using standard chiller cycle analysis techniques to evaluate their ability to act as diluents for R22 in sealed and semi-hermetic systems. The working conditions selected for analysis are typical of air conditioning systems. Since in these mixtures the composition of the liquid and vapor phases at a given temperature is different, then to determine the temperature boundaries of the cycle used the average temperature shift points in the evaporator and condenser; the same conditions were used to evaluate the behavior of R22.

Pentane was present in an amount of 4 wt.% Based on the total weight of the mixture R125 / R134a. To simplify the calculations, this small amount of pentane was not taken into account.

A cycle analysis was performed for the following R22 diluent formulations:

1. Composition comprising 64% R125: 36% R134a

2. Composition comprising 44% R125: 56% R134a

In order to determine the effect that the serial dilution of R22 with the above diluents has on the block behavior, the cycle was analyzed with refrigerant compositions containing R22 mass fractions from 1.0 to 0.0. The results are shown in tables 4A and 4B. The dependences of the main parameters are plotted in FIG. 1, where the calculated points are connected by smooth lines.

In the analysis, the following cycle parameters were used:

Cooling capacity 10 kW

EVAPORATOR

The average temperature of evaporation of the liquid 7.0 ° C

Superheat 5.0 ° С

Pressure drop in the suction pipe

(in units of saturation temperature) 1.5 ° C

CAPACITOR

The average liquid condensation temperature of 45.0 ° C

Subcooling 5.0 ° C

Pressure drop in the discharge pipe (in units of saturation temperature) 1.5 ° С

LIQUID PIPELINE

Motor efficiency 0.85

Isentropic compressor efficiency 0.7

Compressor Flow Rate 0.82

PARASITIC POWER

0.3 kW internal fan

External fan 0.4 kW

Monitoring devices 0.1 kW

All formulations have lower discharge temperatures than R22, and therefore exceed it in this regard.

Composition 1 provides a cooling capacity above 90% of the cooling capacity of R22 in the entire dilution range. Mixtures containing more than 45% R22 have a cooling capacity equal to or greater than the cooling capacity of R22. The system refrigeration coefficient (COP) with an accuracy of 2% is close to this value for R22 in the entire dilution range. Therefore, this composition meets the requirements of this invention.

Composition 2 provides a cooling capacity of more than 90% of this value for R22 for mixtures containing more than 20% R22. The system refrigeration coefficient (COP) is almost the same as that of R22 over the entire dilution range. Therefore, this composition meets the requirements of the present invention in the case of mixtures containing more than 20% R22.

EXAMPLE 5

The composition of R32 / R134a / pentane was tested using standard chiller cycle analysis techniques to evaluate its suitability as a diluent for R22 in sealed or semi-hermetic systems. The working conditions selected for analysis are typical of air conditioning systems. Since the composition of the liquid and vapor phases at this temperature is different for this mixture, the midpoints of the temperature shift intervals in the evaporator and condenser were chosen to determine the temperature boundaries of the cycle. The same temperatures were used to obtain data on the behavior of R22.

Pentane was present in an amount of 4 wt.% Based on the total weight of the mixture R32 / R134a. To simplify the calculations, this small amount of pentane was not taken into account.

A cycle analysis was performed for the diluent composition for R22.

In order to establish the effect that the serial dilution of R22 has on the installation behavior by adding the above diluent, the cycle was analyzed for refrigerant compositions containing R22 mass fractions from 1.0 to 0.0. The results are shown in Table 5 and are plotted in FIG. 2, where the calculated points are connected by smooth lines.

In the analysis, the following cycle parameters were used:

EVAPORATOR

The average temperature of evaporation of the liquid 7.0 ° C

Superheat 5.0 ° С

Pressure drop in the suction pipe (in units of saturation temperature) 1.5 ° С

CAPACITOR

The average liquid condensation temperature of 45.0 ° C

Subcooling 5.0 ° C

Pressure drop in the discharge line

(in units of saturation temperature) 1.5 ° C

HEAT EXCHANGER LIQUID PIPELINE / SUCTION PIPELINE

Efficiency 0.3

COMPRESSOR

Motor efficiency 0.85

Isentropic compressor efficiency 0.7

Compressor Flow Rate 0.82

PARASITIC POWER

0.3 kW internal fan

External fan 0.4 kW

Monitoring devices 0.1 kW

All diluent-containing mixtures have lower discharge temperatures than R22 and therefore satisfy the requirements of these specifications. The system refrigeration coefficient (COP) is almost equal to this value for R22 over the entire dilution range. The refrigerating capacity of the refrigerant is at least 98% of the refrigerating capacity of R22 in the entire dilution range. For dilutions above 20% R22, cooling capacity is equal to or greater than that for R22. The discharge pressure is less than 0.05 MPa (0.5 bar) higher than that for R22 over the entire dilution range.

The results of the analysis of the behavior of the air conditioning unit using these operating conditions are given in table 5.

Therefore, R32 / R134a 30/70 meets the requirements of this invention.

EXAMPLE 6

The composition of R32 / R125 / R134a / pentane was tested using a standard chiller cycle analysis program to evaluate its potential as a diluent for R22 in sealed or semi-hermetic systems. The operating conditions selected for analysis are typical of air conditioning systems. Since the composition of the liquid and vapor phases at this temperature is different for this mixture, the midpoints of the temperature shift intervals in the evaporator and condenser were chosen to determine the temperature boundaries of the cycle. The same temperatures were used to obtain data on the behavior of R22.

Pentane was present in an amount of 4 wt.% Based on the total weight of the mixture.

To simplify the calculations, this small amount of pentane was not taken into account.

When analyzing the cycle, the following diluent composition for R22 was used:

A composition comprising 23 wt.% R32, 25 wt.% R125 and 52 wt.% R134a.

To determine the effect that successive dilution of R22 by adding the aforementioned diluent has on the behavior of the unit, the cycle was analyzed for refrigerant compositions containing R22 mass fractions of 1.0 to 0.0. The results are shown in Table 6 and are plotted in FIG. 3, where the calculated points are connected by smooth lines.

In the analysis, the following cycle parameters were used:

EVAPORATOR

The average temperature of evaporation of the liquid 7.0 ° C

Superheat 5.0 ° С

Pressure drop in the suction pipe (in units of saturation temperature) 1.5 ° С

CAPACITOR

The average liquid condensation temperature of 45.0 ° C

Subcooling 5.0 ° C

Pressure drop in the discharge pipe (in units of saturation temperature) 1.5 ° С

HEAT EXCHANGER LIQUID PIPELINE / SUCTION PIPELINE

Efficiency 0.3

COMPRESSOR

Motor efficiency 0.8

Isentropic compressor efficiency 0.7

Compressor Flow Rate 0.82

PARASITIC POWER

0.3 kW internal fan

External fan 0.4 kW

Monitoring devices 0.1 kW

The results of the analysis of the behavior of the air conditioning unit using these operating conditions are given in table.6.

All mixtures containing diluent have a discharge temperature lower than that of R22, and therefore satisfy these specifications. The system refrigeration coefficient (COP) is at least 98% of this value for R22, over the entire dilution range. The refrigerating capacity is higher than that of R22 over the entire dilution range. The discharge pressure is less than 0.2 MPa (2.0 bar) higher than that for R22 over the entire dilution range.

Therefore, R32 / R134a in a ratio of 30/70 meets the requirements of this invention.

EXAMPLE 7

Compositions of refrigerants, including mixtures of R125, R134a and hydrocarbon, were tested for use in a commercial heat pump using a Comfort Aire rooftop mounted heat pump model RNES-60-1a (5 tons of cooling / 19 · 10 ³ W) with a nominal cooling capacity of 59024 J (56000 BTUs) and a rated heating capacity of 59024 J (56000 BTUs). A sight glass was installed on an airtight compressor at the oil level, and temperature sensors were installed on the suction, discharge and liquid lines. Pressure gauges were also installed on the suction and discharge lines.

The system worked both in cooling mode and in heating mode with R22, and the following data were recorded: voltage, current, suction pressure, suction temperature, discharge pressure, discharge temperature, temperature in the liquid pipe, temperature in the evaporator, ambient temperature oil level and return air temperature. Then the load R22 was drained and replaced sequentially with mixtures of 1-6 of the following compositions:

It was found that the oil return was close to the level of work with R22 for all mixtures used, which indicates that the addition of pentane and isopentane / butane provides a suitable oil return. Some mixtures require the addition of up to 20% refrigerant to prevent evaporator icing. It was found that productivity varies with the composition used. Energy consumption was generally lower for all mixtures. The pressures in the discharge line were on average slightly higher in the case of mixtures in which the R125 content was more than 60.5%, and lower in the case of mixtures containing less than 60.5% R125. Suction pressure and discharge temperature were lower with all mixtures used. The superheat measured at the outlet of the evaporator was significantly higher than that of R22, and the temperature difference in the evaporator was usually greater in cooling mode and less in heating mode. It was noted that the addition of pentane and isopentane / butane provided the necessary oil return. Mixtures Nos. 3, 4, and 5 provided maximum proximity to R22 in operating temperatures and pressures.

Claims (18)

1. The composition of the refrigerant, including 1,1,1,2-tetrafluoroethane (R 134a), pentafluoroethane (R 125) and an additive selected from the group comprising a saturated hydrocarbon or mixture thereof, boiling in the range from -5 to + 70 ° C, in which the mass ratio of R 125 and R 134a are in the range,%: R125 50-80 R134a 50-20 2. The composition of the refrigerant according to claim 1, in which these mass ratios are in the range,%: R125 60-80 R134a 40-20 3. The composition of the refrigerant according to claim 2, in which these mass ratios are in the range,%: R125 60-78 R134a 40-22 4. The composition of the refrigerant according to claim 3, in which these mass ratios are in the range,%: R125 64-76 R134a 36-24 5. The composition of the refrigerant according to claim 1, in which these mass ratios are in the range,%: R125 57-78 R134a 43-22 6. The composition of the refrigerant according to claim 5, in which these mass ratios are in the range,%: R125 63-76 R134a 37-24 7. The refrigerant composition according to any one of claims 1 to 6, in which the hydrocarbon additive is selected from the group consisting of 2-methylpropane, 2,2-dimethylpropane, butane, pentane, 2-methylbutane, cyclopentane, hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, methylcyclopentane and mixtures thereof. 8. The composition of the refrigerant according to any one of claims 1 to 7, in which the hydrocarbon additive has a boiling point in the range from 20 to 40 ° C. 9. The refrigerant composition of claim 8, in which the hydrocarbon additive is selected from the group comprising n-pentane, cyclopentane, isopentane and mixtures thereof. 10. The refrigerant composition of claim 9, wherein the hydrocarbon additive is n-pentane. 11. The composition of the refrigerant according to claim 9 or 10, in which this additive further includes butane. 12. The refrigerant compositions of claim 11, wherein the pentane: butane ratio is from 1: 3 to 1: 8, preferably about 1: 5. 13. The composition of the refrigerant according to any one of claims 1 to 12, in which the amount of hydrocarbon additive is from a negligible amount to 10%. 14. The composition of the refrigerant according to item 13, in which the amount of hydrocarbon additives is from 1 to 8%. 15. The composition of the refrigerant according to 14, in which the amount of hydrocarbon additives is from 2 to 4%. 16. The composition of the refrigerant according to any one of claims 1 to 15, together with some R22. 17. The refrigerant diluent, which is the composition of the refrigerant according to any one of claims 1 to 16. 18. A method of modifying a refrigeration system or an air conditioning system that includes R22 as a refrigerant, the method comprising the step of adding a diluent according to claim 17 to the refrigerant of the system.

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