End Users Eye Natural Refrigerants

End users are increasingly looking to natural refrigerants to boost efficiencies and reduce their carbon footprints.

In his educational session at the IIAR 2020 Virtual Conference and Expo, Augusto Zimmermann, Senior Manager at Alternative Systems Global Center of Excellence, said there are several factors driving end users to consider installing natural refrigeration systems or using natural refrigerants in their facilities.

The main force behind this shift is the regulatory landscape that is driven by climate change, he said. This has precipitated a phase-out of synthetic refrigerants and an emphasis on sustainable practices to reduce environmental impacts.

Because of these pressures, the refrigerant landscape is evolving. There are only a few options for future-proofing facilities from upcoming changes in the regulatory environment, Zimmermann said, and those mostly involve transitioning from traditional hydrofluorocarbons (HFC) to natural refrigerants.

With the proper support, this transition does not need to be hugely disruptive and represents a large growth opportunity in the cold storage market, he said.

“We can identify two main players in types of projects. One is industrial ammonia refrigeration systems… the other is large commercial HFC systems. There is a good opportunity for natural refrigerant solutions to play in the space between the two,” Zimmermann said, citing ammonia and carbon dioxide cascade systems and CO2 , transcritical booster systems. Both offer energy and cost savings.

There are several main ways that CO2 transcritical booster systems can improve efficiency, particularly in warmer climates, Zimmermann said, and both solutions can be scaled up or down depending on facility size and capacity.

For climates that are conducive to the operation of an evaporative assisted gas cooler, system operators can use water to their benefit, effectively lowering the operating temperature of the gas cooler. “There are other solutions too, such as parallel compression and vapor and liquid ejectors that improve and enhance the efficiencies of the system,” he said.

For ammonia/CO2 cascade systems, ultra-low charges of ammonia can effectively reduce the operational costs and energy expenditures of a facility. Citing an end-user in Columbus, Ga., Zimmermann explained that their rooftop ammonia rack connects to an evaporative fluid cooler while downstairs in the machinery room a hybrid CO2 rack was attached to a low temperature CO2 direct expansion pump to cool freezers, and a medium-temperature C02 liquid overfeed system running the other system features.

That particular facility showed a rack energy improvement savings of 22 percent when compared to the operator’s previous HFC system that it replaced.

As regulatory, social and financial pressures mount, it makes sense both from an ecological and economic standpoint to switch to natural refrigerants, Zimmermann said. “That’s the bottom line for future proofing.”