A CONVERSIONMcKinney noted a conversion project involving the HFC refrigerant at a grocery store in the Midwest. He said prior to converting the system from R-22 to R-422C, operating conditions were recorded, the existing R-22 was recovered to Environmental Protection Agency guidelines, and the power elements on the TXVs were changed to ones rated for R-422C. The original system’s mineral oil lubricant did not need to be changed out to POE oil.
The conversion closely followed guidelines established by ICOR, according to McKinney, and then the operating conditions were compared to the pre-conversion data.
“The individual compressors showed an increase in capacity and efficiency at all condensing temperatures calculated,” McKinney said.
“The increases in capacity and efficiency are the same for both compressors respectively. The additional capacity allowed one five-horsepower compressor to idle, saving around 5,000 watts continuously. At the lower condensing temperatures the total of the three remaining compressors using R-422C exceeded the total of four with R-22. So reaching the set point occurred quicker, contributing to increased energy savings.”
He added, “The system’s overall performance was more than favorable and all parties involved considered the conversion a total success.”
The cost of converting the power element is offset by other factors, he said. One factor is the ability to continue to use mineral oil rather than more costly POEs. “The return on investment in the form of power savings an equipment owner will enjoy by converting their low or medium temperature R-22 system to R-422C far outweighs the additional cost of replacing the power element.”
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