At last, refrigeration professionals have the perfect replacement for R22 in flooded/recirc. low temp. systems. Many refrigerants have hoped to be the solution but they all fall short.
Capacity: RS-45 (R434a) is unique in being a capacity match for R22 across the range of applications where R22 is commonly found. No other refrigerant mirrors the capacity of R22 at low temperature (-31 F/ -35 C evap) and high temperature (+45 F/ +7 C evap).
Coefficient Of Performance: RS-45 (R434a) has a Coefficient Of Performance (COP)which matches R22 .
Glide: RS-45 is a near azeotropic blend with a very low glide of 1.5 C mking it the best alternative in R22 flooded/Recirc. evaporators/systems.
Compression Ratio: RS-45 has a compression ratio which matches R22 across the range of applications where R22 is commonly found.
Lubricants: RS-45 is suitable with mineral oil ( MO), alkylbenzene (AB) and synthetic oils like polyolester (POE) and polyalkyglycol (PAG) oils. The ability to use mineral oil both reduces cost and avoids the use of hygoscopic synthetic oils which can absorb moisture during maintenance and leaks. POE oil also compromises seals and gaskets resulting in leaks.
Other RS-45 Attributes: Non-flammable, Zero ODP, similar discharge pressure as R22 and considerably lower discharge temperature than R22; which provides significant operating benefits including a much lower risk of oil degradation.
RS-45 can be used to replace R-22 in medium and low temperature applications and in chillers with flooded/Recirc. evaporators with saturated suction temperature of 19 F/-6 C and below.
Because it is a blend, it is recommended that RS- 45 be charged into systems in the liquid as opposed to the gaseous phase. Since there is no need to change the existing lubricant, RS-45 is straightforward to use as the following procedure outlines.
RS-45 is compatible with mineral, POE and alkybenzene refrigeration oils. Since mineral oil in most often found in R22 systems there is no need to change the lubricant.
RS-45 is compatible with all materials commonly used in refrigeration systems previously charged with R22.
In general, materials which are compatible with R22 can be used with RS-45. In addition, it is less likely to have leaking problems since it is not necessary to change over to the expensive and often seal and gasket damaging POE (synthetic) oil when converting a R22 system to RS-45.
None of the components of RS-45 contain chlorine so that it has no ability to deplete the ozone layer, it is zero ODP
As with all hydrofluorocarbons (HFCs), RS-45 does have a direct global warming potential (GWP), but this is counterbalanced by the low Total Equivalent Warming Impact (TEWI) of the system.
ComStar International Inc., a chemical company with more than 44 years of experience, is one of only a few companies in the world that have "DROP-IN" direct replacement HFC refrigerants for in-place R12, R22 and 502 systems. ComStar is a leader in the development of environmentally safe, industrial strength chemical products for the HVACR industry sold worldwide through leading HVACR wholesalers and distributors.
System Charge Amout
The refrigerant charge needed for a system is based on liquid volume. Therefore, a system will take the same amount of liquid R22 as it would RS-45. However, since the molecular weight of RS-45 is heavier than R22 it means it will take a higher amount of pounds. RS-45 does have a different specific volume than R-22, about 10% less in liquid form and about 20% more in vapor form. Usually the vapor volume of the system is generally larger than the liquid volume so on average about 15% more RS-45 may be required.
In many cases, the system charge needed to operate will vary from season to season depending on a variety of climate conditions. Winter operation usually requires more refrigerant than summer operation. Also, you have to take into consideration if the system had been shut down for some time. As an example, if the system manufacturer recommendation is 7000 lbs of R-22 this same system may require up to 8050 lbs (15% more) of RS-45 due to the difference in density. In summer operation it may be able to operate at something less than 7000 lbs of R22 or 8050 lbs of RS-45.