Moreover, HFOs produce TFA and R23, putting the future sustainability of our planet at risk, said Collin Bootsveld of Colruyt Group.
Collin Bootsveld, Colruyt Group, speaking at a previous ATMOsphere event.
Natural refrigerants outperform f-gas refrigerants in energy efficiency and are less costly, proclaimed keynote speaker Collin Bootsveld, Project Engineer for Belgian food retailer Colruyt Group, at the ATMOsphere Europe Summit 2021 conference, which ran online from September 28-29.
"I really do not see why you would have a problem using natural refrigerants (versus chemical refrigerants) in terms of energy efficiency and costs," said Bootsveld, in his presentation, “Refrigerants Deep Dive — from an End User Perspective.” (ATMOsphere Europe Summit 2021 is organized by ATMOsphere (formerly shecco), publisher of this website.)
Bootsveld was referring to data taken from a Dutch 2018 study that compared the various thermodynamic properties of refrigerants (table shown below).
"I am using this table to make the point that if you look at the Coefficient of Performance (values), they are almost the same for every refrigerant," he said. The evaporation energy value (in the column titled "Qe kJ/kg") Bootsveld added, is the highest for ammonia, indicating that ammonia, in terms of thermodynamic energy efficiency, was "always the best refrigerant whenever you can use it."
Bootsveld also highlighted that the evaporation energy value for propane (R290) was much higher than the two chemical refrigerants listed. Colruyt is a dedicated user of R290/glycol chillers for its medium-temperature food products, as well as isobutane (R600a) in stand-alone chest freezers and R290 heat pumps to heat stores.
The volumetric cooling capacity values (in the column titled VCC kJ/m3), which indicates "how much volume needs to be compressed in order to have the cooling process," Bootsveld added, showed that the chemical refrigerants have a lower volumetric cooling capacity. "This means that you would need a larger compressor, which impacts my investment costs."
Look at the life cycle of refrigerants
Bootsveld also stated in his keynote address that there needs to be more emphasis placed on the "life cycle effects" of refrigerants rather than the "single component effects." These include:
- Emissions during refrigerant production
- Emissions during use of refrigerant
- Secondary emissions due to environmental degradation
To highlight the risks associated with continuing to use HFOs, Bootsveld cited the fact that certain HFOs (notably HFO-1234yf) degrade into trifluoroacetic acid (TFA) in the environment. TFA belongs to a category (PFAS) that are described as "permanent chemicals," said Bootsveld. "They stay in our world forever. They accumulate in water. Once it is in our drinking water, we can never get it out." In addition, Bootsveld cited research suggesting that "R1234ze is going to convert partially into R23, which is the worst ever HFC we have produced."
In his conclusion, Bootsveld highlighted the issue of continuing to experiment with the use of HFOs and the probability of negative outcomes over the next few decades.
"Our planet is one spectator across time," said Bootsveld. "We are doing experiments with our planet. What if, in 20 years’ time, we conclude that it was really a bad idea to use HFOs. The waste that this has caused is not going to go away. In my personal opinion, I think we cannot take that chance. We cannot take that risk."
“"We are doing experiments with our planet. What if, in 20 years’ time, we conclude that it was really a bad idea to use HFOs ... We cannot take that risk." — Collin Bootsveld, Colruyt Group