Super Radiator Coils copper tubes
Super Radiator Coils's Phoenix, Arizona, facility. Source: Super Radiator Coils.

Super Radiator Coils Receives UL Listing for ⁵⁄₁₆ in Copper Tubes for Use in ‘High-Pressure’ CO2 Coil Applications

The company offers ⁵⁄₁₆in, ⅜in and ½in copper tubes for CO2 refrigeration systems with working pressures between 1,740 and 2,000psi.

U.S. coil manufacturer Super Radiator Coils (SRC) has announced that its ⁵⁄₁₆in (7.94mm) outside-diameter (OD) copper tubing with a wall thickness of 0.035in (0.88mm) for use in high-pressure CO2 (R744) coil applications has received UL Listing.

The ⁵⁄₁₆in tube is now approved for coil applications in working pressures of up to 2,000psi (137.9bar) depending on the UL model, SRC said in a press release.

According to SRC, it is now able to offer a “full complement” of UL listed copper tube products for high-pressure CO2 coil applications. This complement comprises ⅜in (9.52mm) OD tubes with a wall thickness of either 0.035 or 0.045in (0.88 or 1.14mm) rated for 1,740 or 2,000psi (120 or 137.9bar), respectively, and ½in (12.7mm) OD tubes with a wall thickness of 0.045 or 0.049in (1.14 or 1.24mm) for 1,740 or 2,000psi, respectively.

“The push for natural refrigerants gave us a new challenge, designing and manufacturing coils that need to perform at our highest-ever pressure ratings and be available in multiple tube sizes,” said Gail Miller, a Sales Application Engineer at SRC who led the project. “This is a fantastic first step toward what’s to come as our industry increasingly pursues environmentally friendly practices.”

The process of producing the UL-listed products occurred at the company’s Richmond, Virginia, facility. However, the certifications apply to products manufactured at all of SRC’s locations, including those in Minneapolis, Minnesota, and Phoenix, Arizona.

Chicago-based UL operates as a third-party testing laboratory. Its listing indicates a product meets national standards for safety and sustainability.

“Hopefully, [our endeavor] lays the groundwork for more CO2 heat exchanger installations nationwide,” Miller said.

In 2021, SRC supplied coils for a CO2 air-cooled gas cooler to support Washington State-based chiller manufacturer Pro Refrigeration in developing a CO2 chiller for the dairy industry. Wynand Groenewald, Director at Future Green Now, a South African consultancy that helped Pro Refrigeration develop the system, said at the time, “Access to required components is not where it should be yet, but what this project did show me is that suppliers are ready to bring what is required to the market.”

Founded in 1928, SRC manufactures custom plate fin heat exchangers and is headquartered in Chaska, Minnesota.

A growing CO2 market

According to ATMOsphere’s “Natural Refrigerants: State of the Industry” 2023 report, there were 3,428 transcritical CO2 refrigeration systems in North America, an increase of almost 50% from 2022. ATMOsphere is the publisher of

A survey of 13 retailers, representing 18,000 U.S. stores, conducted by the North American Sustainable Refrigeration Council (NASRC) indicates that the demand for R744 will reach 13 million lbs (5.9 million kg) by 2027, up from just 3 million lbs (1.4 million kg) in 2023. Danielle Wright, Executive Director of the NASRC, presented the survey data at the ATMOsphere (ATMO) America Summit 2023 held in Washington, D.C.

“Hopefully, [our endeavor] lays the groundwork for more CO2 heat exchanger installations nationwide.”

Gail Miller, Super Radiator Coils

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