29 September 2010
Refrigerant differences may not be significant, long term
A COMPARISON study of HFC and CO2 refrigeration systems has shown that each need time to reach their best level of performance and minimise climate impact. The report suggests that the financial and environmental gap between the different refrigerant solutions can be closed and the choice of refrigerant will then make no significant difference any longer.
This can be achieved either by improving HFC-based refrigeration systems in line with the requirements of the F-gas regulations or via the maturation of CO2 based refrigeration systems.
The study conducted by the British environmental consultants SKM Enviros and commissioned by the industry expert organization EPEE sheds light on the relative importance of the choice of refrigerant for the global climate impact of a refrigeration system and thus on the persistent myth that using one particular refrigerant is the universal remedy for supermarket applications.
SKM Enviros compared four typical refrigerant system combinations: R404A DX MT/R404A DX LT, R404A DX MT/Cascade CO2 DX LT, R404A indirect MT/Cascade CO2 DX LT and a transcritical CO2 DX MT/cascade CO2 DX LT system.
The performance of the R404A system and the R404A/CO2 cascade system were found to be virtually identical with the indirect R404A /Cascade CO2 system consuming significantly more power than either of these two systems. It was found that CO2 based systems are likely to be most energy efficient in average and colder climates, where they consume between 5-10% less energy than the R404A systems. The crossover point was at around 15ºC.
By reducing refrigerant leakage, using lower GWP refrigerants (eg R134a), making installations more efficient and giving technology more time to mature, the study predicts that the greenhouse gas emissions of the compared systems could be reduced by around 50 to 60%.