International.
After running some vaporization tests on four different refrigerants, a group of researchers from the University of Padua found that R290 offers the greatest potential to replace the widely used R32 in various heating and cooling applications, by virtue of its heat transfer properties.
Azzolin et al., in their work Developments on heat transfer with low-GWP refrigerants, tested the heat transfer performance during condensation and vaporization of new fluorine-based refrigerants, including hydrofluoroolefin (HFO) R1234ze and a mixture of HFCs – compared to hydrocarbon R290.
The researchers compared these alternatives to the commonly used HFC R32, which some HVAC&R industry players are touting as a response to the European Union's gas regulation phase-down requirements. The research involved subjecting each fluid to vaporization, condensation, and pressure drop tests.
During vaporization, the researchers found that R32 had the highest heat transfer coefficient and the new HFC mixture had the lowest heat transfer performance of the four refrigerants.
R290 came in second place in the same conditions and was closely aligned with R32.
"Both R32 and R290 show similar heat transfer coefficient values [....] And on average the heat transfer coefficient of R290 is 6% higher," say Azzolin et al.
"During condensation assays, R32 and R290 show similar heat transfer coefficient values that are 30%, 29% and 18% higher than those of R1234ze(E) at 800, 400 and 200 kg m-2 s-1 [of refrigerant charge]," the researchers found.
Propane, they concluded, was the most similar to R32 and required the same amount of refrigerant charge, making it an efficient refrigerant.
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