Embraco webinar reveals the substitution value of hydrocarbons as more HFCs get phased-out

What makes an ideal refrigerant?

Hosted by RSES and navigated by Embraco’s John Prall, ‘Refrigeration 101’ is a crash course on the refrigeration cycle and the various parameters of what makes an ‘ideal’ refrigerant. 

Prall explained that there are several factors that add up to making the ‘ideal’ refrigerant. He first highlighted that it must possess favourable thermodynamic properties including:

• Low boiling point
• High heat of vapourisation
• Moderate liquid density
• High vapour density
• High critical temperature

In addition to this, the refrigerant should also be non-corrosive, safe (free from toxicity and non-flammable) and have no ozone depleting potential and a minimal global warming potential (GWP). But Prall reiterated that a “refrigerant suitable for one application may not be suitable for another application”.

When comparing hydrocarbons with HFCs such as R404A and R22, the difference in GWP was evident with R290 having a GWP of <4 compared to 3920 for R404A and 1810 for R22.

When looking at how hydrocarbons stack up against other refrigerants, the discharge pressure and suction pressure of R600a and R290 are much more favourable compared to R22 and R404A, with R600a in particular having a system working pressure (at 25°C ambient temperature) that is lower than atmospheric pressure.

Q&A section canvasses current state of refrigeration and refrigerants

While the main focus of the webinar was on introducing a traditional refrigeration cycle, the components and refrigerants that are typically found in this system, the Q&A section centred on the substitution value of hydrocarbons for high-GWP HFCs that are being phased-out.

When asked if R290 could replace R404a in the comfort-cooling sector, Prall stated that: “In mini-splits, it definitely has a use… if the charge limits do get increased, it would make perfect sense. However, I don’t think we’ll ever see central air conditioning in the house using R290 as it would require a bit too much refrigerant, particularly as it would be occupied by families.”

When asked about the use of R290 in self-contained refrigeration in the U.S. and whether Europe’s regulatory framework has affected the U.S. market for R290. Prall explained that:

“They [EU regulations] have already influenced the market. For self-contained refrigeration, the market has already almost completely switched over, as refrigerants that have a GWP of over 2,500 will be banned by 2020 and anything over a GWP of 150 being banned by 2022.”

“In the case of self-contained refrigeration, the U.S. Environmental Protection Agency has banned the use of R404a and R134a for 2020. So the U.S. is a little more aggressive in some cases than Europe but the U.S. has some refrigerants with some higher GWP SNAP approved refrigerants than what Europe would allow.”