Embraco sees HCs as the low GWP solution
In the light of the European F-gas regulations and a global move towards lower GWP refrigerants, the Brazilian manufacturer has carried out extensive tests to assess the transitory solutions towards low GWP refrigerants.
A recently published position paper concludes that R407F, R407A, R448A or R449A are not suitable as drop-in substitutes for systems using Embraco R404A compressors. Embrace says that usage of these refrigerants may require system changes such as, system condensing temperature reduction (larger condenser, improved ventilation) or return gas temperature reduction in order to achieve a similar thermal profile as with R404A.
“Final application needs to be validated by Embraco Technical Support Team case by case,” it says and usage in systems operating under high compression ratios in particular should be avoided.
However, Embraco does consider R452A as a drop-in alternative to R404A.
The HFO R1234yf is viewed as an acceptable long term alternative to R134a, but problems with its A2L “mild” flammability have not yet been solved, says Embraco. With current legislation limiting the charge to150g, Embraco sees the use of all A2Ls being very limited in mid-term.
While Embraco already offers some yf compressors, it does not consider R1234ze as a valid R134a alternative because of its low specific cooling capacity.
The hydrocarbon refrigerants isobutane (R600a) and propane (R290) are seen as the best, long term solution for light commercial applications both in low and medium pressure.
Embraco points out that propane is already widely used on several commercial and air conditioning applications and says that most of the existing light commercial application can be converted to use HC refrigerants.
In the case of larger applications, Embraco sees multi-circuit systems as being a feasible option and already applied in some systems.
“There are still existing barriers for use of hydrocarbons in some types of applications related to the safety issues of final product, its cost and appliance manufacturing line investments,” says Embraco.
An important step to allow wider use hinges on possible updates of the standards for the use of A3 class refrigerants.
“Today, present IEC standard used for hermetically sealed applications, EN60335-2-89, is limiting to 150g the charge of any flammable refrigerant,” the document states.
“Under IEC SC61C/WG4 working group, the industry is trying to define specific additional measures needed to allow higher charge levels without increasing risks above the existing standard.”
Isobutane is accepted as a valid energy efficient alternative solution for small appliances, but is described as having significant cooling capacity limitations. The main applications are seen as small chest freezers, bottle coolers and wine coolers, etc.
While very similar to propane, propylene (R1270) is slightly less efficient and is therefore only considered suitable for very specific applications. Embraco says it has no plans to develop propylene compressors.
The position paper can be viewed and downloaded here.
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