RS-24 is a “Drop-in” alternative for R12 which also provides a long term solution at the same time. It provides, therefore, a one change solution to the replacement of R12 at minimal expense.
The best drop in replacement for R12 is R152a, which is most easily bought as computer duster (seriously). It has very similar psychrometric performance to R12 so heat exchanger sizing is the same, pressure switches still work as intended, and system performance is the same as stock when everything is working well.
An HCFC Replacement Refrigerant for R-12
Freon™ 409A carries an ASHRAE A1 safety classification and blends R-22, R-142b, and R-124. It can be used in medium- and low-temperature positive displacement equipment.
As R12 is now being finally phased out, older refrigeration machines need an alternative. Whatever you do, DO NOT USE R-134a in a R12 System! Instead, use a Propane + Isobutane combination, also known as 12a or HC-12a. 12a is also non-ozone depleting, and directly compatible with R-12's compressor oils. Sin.
However, R134a is not a 'drop-in' replacement for R12 because there is a need to change the compressor lubricant and expansion valve. Changing over from R12 to R134a can therefore be an ex-pensive and time consuming procedure.
Drop-in and long-term R12 replacement
The properties of RS-24 make it an almost perfect match for R12 with its compatibility for traditional and synthetic lubricants, similar performance, lower discharge temperature, non-flammability and relatively short atmospheric lifetime.
The refrigerant that is commonly used as a direct drop-in replacement for R-12 in retrofitting mobile air conditioning systems is R-134a (HFC-134a).
Answer: Answer is R134a. R134a is HFC , used in automotive air conditioning and as a replacement for R12 in medium and high temperature refrigeration applications , such as commercial and domestic refrigeration and chillers.
R600a is a good replacement for R12
However its smaller volumetric capacity and higher pressure ratios, limit it to very small capacities. With regard to R600a, it has a lower molecular weight, 58.1 kg/kmol in comparison to R134a, 102 kg/kmol, which results in a lower charge for Isobutane.
Propane makes a good substitute for R12 with very little modifications.
Some notable substitutes for R134a [10] in AAC based on the preceding studies are R1234yf [[11], [12], [13], [14]], R1234z (E) [[15], [16], [17]], R152a [[18], [19], [20]], R290 [21,22], R744 [[23], [24], [25]], R430A [26,27], and R444A [28], etc.
The use of R134a as an alternative refrigerant in unmodified CFC12 systems and heat pumps has been investigated. Although R134a can achieve acceptable efficiencies in comparison with R12, the main problem in retrofitting R134a into existing systems was the need for a new refrigerant compatible with it.
Duracool 12A is an ideal replacement for the R12, R134A and 1234YF gases that can be found in automotive refrigeration circuits.
R-401A & R-409A are refrigerants employed as replacements for R-12 in medium temperature refrigeration systems.
Freon™ Hot Shot-2 (R-417C) is a non-ozone depleting A1 refrigerant that can be used as a direct replacement into existing systems that are still operating with R-12, R-134a, or R-500.
Freon™ MP39 is an HCFC retrofit refrigerant for R-12 in stationary positive displacement air-conditioning and refrigeration systems such as walk-in coolers, beverage dispensers, vending machines, and supermarket systems. Field experience has shown that no oil change is needed in many unitary and close-coupled systems.
R600a (isobutane) is a hydrocarbon that is becoming increasingly popular due to its low Global Warming Potential (GWP). It is the refrigerant of choice for domestic and light commercial refrigeration units, including fridges and freezers, drink dispensers and standalone display units.
Dichlorodifluoromethane (R-12) is a colorless gas popularly known by the genericized brand name Freon (as Freon-12). It is a chlorofluorocarbon halomethane (CFC) used as a refrigerant and aerosol spray propellant.
RS-24 is a “Drop-in” alternative for R12 which also provides a long term solution at the same time. It provides, therefore, a one change solution to the replacement of R12 at minimal expense.
R134a was the first chlorine-free HFC that was found as a replacement for R12 [8]. Some studies have been carried out on the performance of R134a compared with that of R12 in vapour compression refrigeration systems.
Final answer: R-134a is the most commonly used refrigerant to replace R-12 in new household refrigerators, due to its ozone-friendly properties and suitability for refrigeration.
The Duracool 12a is used to replace the R12 and R134a gases and owes its success to its ecological qualities. It is an hydrocarbon gas with zero impact on the ozone layer. It requires only 35% of the load weight of the R12 and 40% of that of the 134a.
Examples of Drop-In Refrigerants:
R437A and R438A: Replacements for R22 in refrigeration and air-conditioning systems. R449A or R448A: Alternatives to R404A, with significantly lower GWP. R513A: A replacement for R134a with low global warming potential (GWP)
In order to legally use R134a refrigerant in an R12 system, it must be converted or retrofitted to be able to properly use R134a, and all R12 must be properly discharged and captured prior to charging with R134a.