Part of the AHRI’s Low-GWP Alternative Refrigerants Evaluation Programme, the tests were carried out by US manufacturer Friedrich on the 1 ton SPVH in its design and development centre in San Antonio, Texas.
The unit, model VHA12R34RTM-A, designed for R410A, employed a rotary compressor charged with POE oil. The unit was initially charged with the specified charge of R410A. After the R410A tests the same SPVH was evacuated and recharged with a lighter charge of R32. Both tests were performed to AHRI Standard 390 and ANSI/ASHRAE Standard 58 in the same test room.
The capacity and efficiency of R32 refrigerant was found to be comparable to the R410A system without significant equipment modifications. However, it was felt that the R32 capacity and efficiency would improve with further subcooling of the outdoor coil circuit through adjusting the metering device and optimising the refrigerant charge.
A full copy of the report is available here.