The relative merits of R32 can be summarized based on a comparison of theoretical properties as shown in Table 1 :
- considerably lower refrigerant cost than R410A and potentially better affordability
- available now in high volumes globally since it is 50% of R410A composition
- 8% higher critical temperature, better performance at higher ambient conditions
- similar pressure and pressure ratio, a close drop-in replacement for R410A without major system redesign
- 9% lower liquid density, lower system charge requirement
- 28% lower vapor density and lower system mass flow rate, about 50% lower pressure drop expected
- higher volumetric capacity despite the 28% lower mass flow due to 43-50% higher latent heat
- 41% higher liquid thermal conductivity, higher heat transfer coefficient at same mass flux
- No glide and potential to optimize heat exchanger with smaller tube volume for further charge reduction
The disadvantages are cited below:
- A2L mild flammability rating (difficult to find a Low-GWP A1 non-flammable fluid)
- higher compressor discharge temperature from higher vapor specific heat
- New oil likely required since existing polyolester (POE) oil is not miscible with R32
Overall, R32 seems to offer more advantages than disadvantages. Its lower cost provides incentive for investing development time for mitigating its disadvantages through compressor and system design optimization.