Multi-component refrigerants of HCFC groups
Compiled by Rolando Delgado and Sergio Montelier
Versión en Español English version
It is a zeotrope average pressure blend with temperature glide Dtgl= 4...5К. Physical qualities of this blend are given in tables down. R401A saturated vapor pressure is a bit higher than that of R12 (correspondingly 1,27 and 1,08 МPа at 45 oС).
Depending on operation conditions, cold-productivity of the refrigeration system, where there has been used R12 before, is 5...8 % increased. R401A refrigerant is not compatible with mineral oils, therefore, during retrofit it is necessary to charge the refrigeration aggregate with alkylbenzene oil. Substitution of a filter-dehydrator is also required.
The refrigerant is recommended to use for retrofit in high - (higher than О oС) and mean-temperature refrigeration facilities (hermetic, semihermetic compressors and compressors with open drive), domestic refrigerators and fixed air-conditioners for R12 substitution.
Cold-productivity of the refrigeration system operating on R401A is comparable to cold-productivity of the systems on R12 at boiling temperatures higher that -25 oС. Dependence of saturation pressure on temperature is given on the figure. In the table there are given the results of comparison of theoretical refrigeration cycles at operating on R12 and R401A.
It is a zeotrope average pressure blend with temperature glide Dtgl ~ 5 К. Physical qualities of this blend are given in Table down. Saturated vapor pressure of R401B (Fig.) is a bit higher than that of R12 (correspondingly 1,36 and 1,08 МPа at 45 oС).
The refrigerant has been developed for retrofit of the low-temperature equipment of refrigeration transport systems (for example, refrigerated containers), operating on R12 (boiling point -20...-30 oС), as well as of mean-temperature commercial equipment and domestic refrigerators.
During retrofit of the operating refrigeration equipment, it is necessary to substitute a filter-dehydrator and to charge the refrigeration cooling system with alkylbenzene oil. Cold-productivity of the systems operating on R401B refrigerant is compatible with cold-productivity on R12 at boiling points lower than -23 oС.
R401B refrigerant can be also used for substitution of R500 in the operating equipment.
It is a zeotrope average pressure blend with temperature glide Dtgl = 4,5...5 К. Physical qualities of this blend are given in the table. The refrigerant is intended for retrofit of operating on R12 refrigeration trucks. Thermodynamic and physical qualities of the refrigerant allow to fulfill effective and safe substitution of R12. At retrofit of the facilities operating on R12, before changing for R401C refrigerant they substitute the filter-dehydrator and mineral oil for alkylbenzene.
R409A refrigerant. It is a blend on the base of HCFC: R22, R124 and R142. Mass proportions of the components constitute correspondingly 60; 25 and 15. Boiling point at atmospheric conditions is -34 oС. Molecular mass is 97,4 gm/mole. Ozone depletion potential ODP = 0,05. The refrigerant is incombustible and non-poisonous, compatible with mineral, as well as with alkylbenzene oils. Intended for retrofit of the refrigeration systems of the mobile commercial transport equipment, domestic refrigerators, industrial refrigeration facilities with piston and screw compressors.
С10М1 refrigerant. С10M1 refrigerant (2412-003-32837395-98), developed by "ASTOR" company and produced under registration brand ASTRONTM 12, - it is a three-component blend on the base of hydrochlorfluorocarbons R22/R21/R142b, having limited period of service life. С10М1 blend is intended for retrofit of the refrigeration systems operating on R12.
There are produced the blends of two brands (А and B), differed by mass proportions of the components: in С10М1 blend of A brand - R22, R21 and R142b mass proportions of the components are correspondingly 65; 5 and 30%; in С10М1 blend of B brand - 65; 15 and 20%.
Composition of the blend has been selected so that operation performance of the equipment with these refrigerants would minimally differ from the parameters obtained at operation with the substituted refrigerant R12.
С10М1 refrigerants are non-toxic, incombustible, and as to their basic physical-chemical, thermodynamic and operational characteristics, they are close to R12 refrigerant.
Advantages of С10М1 refrigerant (ASTRONTM 12) with respect to foreign analogs are the following:
The technology of the operating refrigeration equipment change from R12 refrigerant for С10М1 blends has been developed and optimized in the process of experimental operation of the corresponding equipment. Mandatory requirement for the blends using is charging of the equipment with a refrigerant in a liquid phase. In case of leakage of 30...35 % of С10М1 refrigerant out of the system, topping -up with the blend of the same composition is fulfilled in the process of operation.
Basic stages of the refrigeration equipment change for С10М1 with using the technology of "drop in" are accomplished in the following sequence:
Evaluation of parameters of the equipment where R12 is supposed to change for the alternative refrigerant - measuring of the pressure of discharge and suction in the compressor, as well the temperatures in the evaporator and condenser;
when stopping the machine, elimination of R12, determination of mass (weighing) of the eliminated refrigerant;
selection of oil samples and control of its quality (acidity, moisture load, mechanical foreign bodies); in case of negative results - substitution of the oil for a new one;
hermetic encapsulation of the facility, vacuum degassing of the system to eliminate R12 residual;
charging of the system with С10М1 refrigerant in a liquid phase - 80...90 % of R12 mass;
compressor start, its output for operating parameters;
evaluation of the equipment characteristics when operating on С10М1 blend.
R22/R142b blend. The refrigerant is an incombustible zeotrope blend, whose components have their service lives restricted by the Montreal Protocol.
The results of testing of domestic refrigerators charged with R22 and R142b blend with the mass proportions correspondingly 0,6 and 0,4, performed in Astrakhan State Technological University and Moscow Power Institute, have showed that energy consumption remained almost the same as when using R12. Using of this blend is purposeful during retrofit of the operating refrigeration equipment; at that substitution of oils, filters-dehydrators, as well as alterations in the refrigerating aggregate design, are not required. R22 and R142b blend can serve as a transient refrigerant not only in the domestic equipment, but also in the other refrigeration equipment.
High Pressure Refrigerants
The sphere of application of the refrigerants for retrofit and charging of the new equipment is given in the table.
R402A refrigerant. It is a near-zeotrope blend with temperature glide less than 1,6 К. Basic physical qualities are given in the table down. The refrigerant has been developed for retrofit of the equipment charged with R502 and operating on low boiling point (-40 oС), where it is necessary to achieve discharge temperature peculiar to R502. Depending on operation conditions, cold-productivity of the equipment operating on this refrigerant is, as a rule, about 11% higher than that of the equipment on R502. Energy consumption is also a bit higher. R402A refrigerant compared to R502 at the same conditions has pressure, which is 13...15 % higher.
R402A is compatible with mineral oils, with blends of mineral and alkylbenzene oils, as well as with alkylbenzene and polyester oils. It is recommended to use R402A in combination with alkylbenzene oil. During retrofit, a filter should be replaced.
Non-zeotropness of the blend can cause changing of its composition and, correspondingly, impairment of the refrigeration system performance in the process of a continuous operation.
R402B refrigerant. It is a near-zeotrope blend with temperature glide less than 1 К. Basic physical qualities of R402B refrigerant are given in the table.
The refrigerant has been developed as a substitute of R502 for retrofit of the refrigeration equipment where it is necessary to optimize a refrigerating factor. In cases when consideration of energy effectiveness is determining, preference is given to R402B refrigerant which ranks over R502 as to its energy characteristics (table down). The refrigerant is perspective for using in commercial refrigeration equipment where boiling point in the refrigerated capacity does not drop lower than -30 oС. It is important that if boiling point reaches -40 oС, discharge temperature can be 15 oС higher than that of R502. Such increase of temperature can negatively effect the lubricating system and reduce service life of the compressor.
The refrigerant is compatible with mineral oils, with blends of mineral and alkylbenzene oils, as well as with alkylbenzene and polyester oils. During retrofit, a filter-dehydrator should be replaced.
Due to the fact that composition of the refrigerant is multi-component, there can occur selective loss of any of the components because of the leakage caused by looseness of the refrigeration system or changing of mass in its separate elements, which will cause impairment of energy characteristics of the equipment.
Combustibility of high pressure refrigerants. All high pressure refrigerants considered before are defined as incombustible at the atmospheric pressure and temperature higher than 80 oС. However, tests show that R22 refrigerant can become combustible at pressure 5,15 o 105 Pа and ambient temperature when it is mixed with the air with the air volume fraction 65 % or more. Therefore, one cannot allow R402B and R402A refrigerants to mix with the air when leakage, especially in high concentrations with the pressure higher than the atmospheric one.
R408A refrigerant. Developed by concern "Elf. Atochem" as an alternative to R502 during retrofit in the operating refrigeration systems. Near-zeotrope blend, consists of R22, R143a and R125 components. Mass composition (%) is correspondingly 44; 4 and 52. Intended for the use in the mobile transport refrigeration systems, as well as in industrial refrigeration facilities with piston and screw compressors.
R408A and R502 at the same temperature have close pressures; condensation temperature is 10 К higher. Cold-productivity of the cycle is about 1...10 % higher, than at operation on R502.
R408A liquid density is lower than that of R502 refrigerant (see table) and, as a consequence, required charging mass, that is available receivers, pipeworks and pumps designed for R502, can be used for R408A.
Moreover, reduction of charging mass is important to keep in mind in small facilities in order not to allow re-charging to avoid increasing of pressure and consumed power. In small facilities, reduction of charging can reach 25 %, and in big ones - 15 %.
As it can be seen in the table, R408A is more hygroscopic than R502, which is connected with the necessity of strict observance of this refrigerant transit, system charging, etc. Liquid thermal capacity at constant pressure is higher than that of R408A, which causes considerable loss at orificing. It can be avoided by increasing the liquid overcooling in the condenser. Saturated liquid thermal conductivity is also higher than that of R408A. It increases efficiency of heat transfer, and as a result, improves thermodynamic characteristics of the facility, which has been proved by tests.
Consumed power at negative temperatures is 7 % lower, which is important at retrofit because it reduces danger of locking or burn of electric motor. Therefore, there are no restrictions for the use of R408A even in small hermetic compressors.
Due to high polarity of one of the components (R143a), R408A, refrigerant is reciprocally resolvable with both alkylbenzene and mineral oils. In compact refrigeration systems at standard conditions, it is enough to ensure the oil return to the compressor. R408A refrigerant can be used also in combination with polyester oils.
With respect to sealing materials, R408A is less aggressive that R502.
Molecular sieves being used for R502 and R22 serve as filters-dehydrators.
Source: Company "Allchem" Web Page.