R32 passes high ambient test
SAUDI ARABIA: Tests in Saudi Arabia have indicated that, as well as having better performance, R32 might be compatible with existing R410A air conditioners in high ambients.
Comparison tests were carried out under AHRI’s Low-GWP Alternative Refrigerants Evaluation Programme on a standard 21kW rooftop packaged air conditioner designed for R410A and manufactured by leading Saudi manufacturer Zamil.
Tests using R32 in the same unit – after swapping in an R32 compressor and larger TXV – showed that the lower GWP refrigerant now being considered as a replacement for R410A in air conditioning systems exhibited higher capacity and performance at higher ambients.
The test results, recently released by AHRI, were carried out in the Ikhtebar laboratory in Dammam. Ikhtebar is one of the leading labs in the Gulf region and the first to attain accreditation for compliance with international testing standards in the Middle East.
The model selected for the baseline test used a ZP61K5E Copeland Scroll compressor. For the R32 test the compressor was changed to a prototype Copeland Scroll R32 compressor which had a slightly larger displacement volume than its R410A counterpart – 7.18ft³/min against 7.06ft³/min. The R32 charge was 12% lower than the R410A charge but lubricant charge was 34% more as recommended by the compressor manufacturer.
While both tests showed a capacity reduction at high ambients R32 exhibited a capacity up to 16% higher than R410A. The energy efficiency ratio was also improved with R32 showing up to 10% improvement on R410A.
However, R410A was shown to have a better integrated energy efficiency ratio (a measure of part-load performance) by 4% compared to R32.
A negative characteristic of R32 is its comparatively high discharge temperature. At around 55ºC ambient, the R32 discharge temperature was found to be around 24.4 ºC higher than R410A but the POE oil, when tested, was not found to have suffered any negative effects from these elevated temperatures.
The test report can be found on the AHRI website.
Related stories:
R32 performs well in drop-in test – August 18, 2015
USA: The lower GWP refrigerant R32 is said to have shown similar performance to R410A in drop-in tests on a single-package vertical heat pump. Read more…
