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Equipment manufacturers are generally following the guidance of their OEM compressor suppliers. Emerson Climate Technologies, manufacturer of Copeland® brand products, has said that R-422B has not been tested or approved for use in Copeland compressors and could void the warranty. It is also reported that a small loss of efficiency will result with R-422B.
An Emerson marketing bulletin dated Nov. 24, 2008 said, “Oil return to the compressor is critical to compressor reliability and the overall long-term reliability of the system. HFC refrigerants such as R-410A and R-407C that are miscible with POE oil are acceptable because they meet oil return requirements. However, HFC refrigerants that claim they can be used with mineral oil are not approved by Emerson for use with Copeland compressors in air conditioning applications. This is because several published sources have demonstrated continued concern with oil return for systems without oil separators, like air conditioning applications. The HFC retrofit refrigerants that are not approved include R-417A, R-422A/B/C/D, R-434A, and R-421A.” However, the jury is still out at one major manufacturing company. Bristol Compressor, a Johnson Controls company, is still conducting studies.
“The company is currently evaluating R-422B,” according to Barry Rust of Bristol, and expects to issue a statement in about three months. So far, the company has nothing negative to say about the possibility of recommending the drop-in for systems.
ICOR, a refrigerant manufacturer, offers its trademarked brand of the R-422B alternative. Gordon McKinney, ICOR president, said about his company’s product, “NU-22B™ is being successfully used in thousands of mineral oil-based air conditioning and refrigeration applications and under the entire range of environmental conditions. NU-22B’s track record of performance is impeccable.
“The science behind NU-22B’s ability as an HFC to work with mineral oil is very simple and cannot be disputed. Using small amounts of hydrocarbons to enhance solubility is a very old and effective practice.”
Regarding the question that surrounds the minute amount of propane that is used in the R-422B blend, McKinney said, “You will find HCs in use with products like DuPont’s HP80 (R-402A) and HP81 (R-402B), which both contain 2 percent R-290 (propane), and pentane which was also commonly used in ultralow-temperature applications where oil return is tested to its limits.”
Neil Roberts was working for Rhodia, a European refrigerant producer, at the time he wrote and presented a white paper at the Purdue Compressor Conference about six years ago. In the study he referenced a blend known as R-417A, which was the original NU-22, according to McKinney.
“Our current version of this blend uses R-600a (isobutene) in place of R-600 (butane).”
Below is an excerpt from Roberts’ white paper.
“It is well known that hydrocarbons have a very high solubility in mineral oils, but they are also totally miscible with fluorocarbon refrigerant fluids. This results in a mutual solubility effect when the refrigerant blend is mixed with mineral oil, i.e., significant amounts of the fluorocarbon refrigerants also dissolve in the mineral oil, which is sufficient to provide the necessary properties to enable oil transport.”
This research suggests that an R-422B blend will work equally well in mineral-based or polyolester-based refrigerant systems.
McKinney said, “NU-22B has far more than a white paper or a few lab tests to prove its worth. It is providing adequate cooling and refrigerating capacity for thousands of active systems everyday and has been for several years without any need for a POE oil change.”
Publication date: 04/20/2009