ATMO America: Simplify CO₂ Systems to Drive Uptake in the U.S., Says Founder of Future Green Now

Simplifying CO₂ (R744) systems with controls focused on annual performance rather than peak operating conditions will naturally drive the uptake of CO₂ refrigeration in the United States, said Wynand Groenewald, Founder and CEO of Future Green Now.

Groenewald, who has 18 years of experience working with CO₂ refrigeration systems, highlighted the benefits of the natural refrigerant using real-world examples in a keynote address at ATMO America 2025. The event, organized by ATMOsphere, publisher of NaturalRefrigerants.com, was held June 11‒12 in Atlanta, Georgia.

“The systems we did 18 years ago were super complex, with unnecessary safety and backup features,” Groenewald said. “However, we’ve learned that simplified systems optimized for annual temperature conditions and integrated with HVAC applications take advantage of CO₂, making it cost-competitive, energy-efficient and user-friendly.”

Future Green Now, a natural refrigerants refrigeration consulting firm headquartered in South Africa, has worked on CO₂ installations in Australia, New Zealand, Europe, North America, South America and Saudi Arabia. One project highlighted by Groenewald included a 5.28MW (1,501TR) transcritical CO₂ system commissioned in February 2021 for an 11,000m² (118,400ft²) South African storage facility owned by PreCool Cold Storage in partnership with the shipping giant Maersk.

Real-world examples: To highlight the economic benefits of CO₂, Groenewald shared data from two transcritical CO₂ installations, each supporting 19,500m² (210,000ft²) facilities with medium-temperature (MT) and low-temperature (LT) capacity. Both facilities, owned by the same company, used adiabatic gas cooling with water reclaim, heat reclaim and hot gas defrost.

• The first facility had an 850MBH (249kW/70.8TR) MT capacity at an SST of 23°F (−5°C), a 220MBH (65kW/18.5TR) LT capacity at an SST of −22°F (−30°C) and a heat reclaim capacity of 150MBH (44kW/12.5TR) at 130°F (54.4°C). 
• It cost 10% more than a comparable HFC-based system to install but reduced energy consumption by 35%.
• The second facility integrated HVAC heating, cooling and dehumidification into the design, with an MT capacity of 780MBH (229kW/65.1TR) at 23°F, LT capacity of 250MBH (73kW/) at −22°F, heat reclaim capacity of 150MBH at 130°F, HVAC cooling capacity of 4,480MBH (1,313kW/373.3TR) at 41°F (5°C) and HVAC heating and dehumidification capacity of 1,500MBH (440kW/125.1TR) at 104°F (40°C). 
• The second installation cost 15% less than a comparable HFC-based system, with a 25% reduction in energy consumption.

Cutting complication: “CO₂ systems focused on a set control point lower costs with less to go wrong, making it easier to teach technicians,” Groenewald said. “Let’s cut costs and design CO₂ systems for ‘low hanging’ opportunities.”

• A common liquid line and a loop system reduce the pipework, cutting costs, as does optimizing the number of evaporators, according to Groenewald.
• “I’ve seen plenty of five-year-old CO₂ machine rooms with parallel compressors with only 100 hours of operating time,” Groenewald said while highlighting unnecessary high installation design costs.

Addressing misconceptions: “We need to combat CO₂ fear-mongering,” Greonewald said, adding that it is just a refrigerant like any other.

• Unlike synthetics, CO₂ is a single chemical with no glide. The high side of a CO₂ system requires high pressure and flash gas bypass valves. However, the operation on the low side always stays the same. 
• “If you take into account that a CO₂ system’s capacity varies with ambient temperatures, you can control superheat without complex measures,” he explained.
• The demand for CO₂ refrigeration has increased the component supply to reduce installation costs, according to Groenewald. CO₂ also offers lower operation and maintenance costs than synthetic systems.

Quotable: “We need to trust CO₂ as a stable, versatile refrigerant,” Groenewald said. “The simpler the CO₂ system design, the easier it is to install, operate and maintain.”