Brazilian compressor manufacturer Embraco has set about determining how easy it is to convert a small light commercial freezer from HFC blend R404A to natural refrigerant propane (R290).
Headquartered in Brazil, Embraco also has factories in Italy, China and Slovakia. It makes 36 million compressors per year.
At this month’s 16th International Refrigeration and Air Conditioning Conference, part of the Purdue series of conferences on HVAC&R, Embraco researchers [Jackson Kruger, Fernando De Borbai , Murilo Favaro] presented their paper ‘Challenges on Converting an Upright Ice-Cream Freezer from R404A to R290 Complying with 150g Refrigerant Charge Restriction’.
The Embraco Brazil researchers told participants how to retrofit an ice cream freezer designed for R404A to use propane instead.
With a global HFC phase-down firmly in the pipeline after last week’s Montreal Protocol talks in Vienna, R290 stands ready as a proven climate-friendly alternative to R404A.
R290 retrofit requires only minor modifications
With R290 and R404A sharing some common characteristics, the researchers said, “the condenser, evaporator, load of specimens and most of the physical elements of the system were kept the same”.
Minor changes were made, however. The figure below depicts the key differences between the R404A (combination A) and R290 (combination B) systems:
The researchers conducted tests to determine whether the new system worked, and whether it was more efficient and better for the environment.
Results show propane to be more efficient, better for environment
System modifications were kept to a minimum except for the expansion device and compressor, so it was easy to change the R404A freezer to propane.
The thermal performance of propane and R404A was similar. The good news for propane, the researchers write, is that it “had a lower temperature average, eliminating any possible doubts about its cooling capacity”.
It also proved more effective for freezing for lower temperatures and in smaller packages than R404A. Furthermore, it was found to be more efficient and in compliance with new US regulations on energy efficiency.
“The TEWI [total equivalent warming impact] was reduced by 11.6% after the migration to a natural refrigerant. Both GWP [global warming potential] and power consumption [contributed] positively to the environmental impact reduction,” the Brazilian R&D team concluded.