The International Copper Association announced an analysis that found heat exchanger coils with small-diameter copper tubes are more energy efficient.

The performance analysis showed that coils with small tubes were as much as 15 percent more energy efficient and used more than 40 percent less tube and fin material than conventional designs.

The coil designs were developed with the aid of design software that optimizes copper tubes and advanced fins for both condensers and evaporators in residential air-conditioner applications.

“These design tools enable the manufacture of optimized heat exchangers that are more efficient, lower in cost and use less copper material in every unit,” said Hal Stillman, director of technology for ICA. “The results allow OEM (original-equipment manufacturer) product design engineers around the world to produce cost-effective and efficient heat exchangers using well-understood and widely used copper-tube plate-fin technology. Some manufacturers are already launching products developed on the basis of the results.”

Heat transfer from the tubes to the fins was simulated and optimized over a wide range of parameters. The performance was systematically analyzed by varying one parameter at a time and calculating the changes in input power, flow rate and heat transfer.

Advanced statistical analysis was applied to allow for a sampling of the design space across many fin parameters. Fin designs of various dimensions and spacing were simulated for various small diameters of tubes.

Performance simulations were carried out at the School of Energy and Power Engineering at Xian Jiaotang University in Xian, China, an air-conditioning and heat-transfer research facility. The research was sponsored in part by the International Copper Association.

“These designs demonstrate the inherent advantages of cost-effective, eco-friendly copper tubes and provide high energy efficiency in a compact package,” Stillman said.