Evaporator coils with small diameter copper tubes deliver same performance with less materials, conclude ICA design study

According to an announcement by MicroGroove, the International Copper Association (ICA), an organisation for promoting the use of copper worldwide, has concluded that manufacturers continue to reduce materials requirements in designs of heat exchangers for air conditioning and refrigeration products through the use of MicroGroove technology. Products made with inner-grooved, small tubes of copper use less material yet deliver the same performance as products made with larger tubes, the announcement added.

Citing an example to corroborate the claim, MicroGroove said that a design study from the Chigo Air Conditioning Company, Foshan, Guangdong, China, had demonstrated the benefits of using small tube copper with microgrooves. Chigo is a member of a small tube copper research consortium that includes the ICA, two universities and several major manufacturers of air conditioning and refrigeration products. The design study was for a residential air conditioning product.

Explaining the process, MicroGroove said that two evaporator coils were made with the same arrangement of tubes, but different tube sizes. The smaller tubes allowed for a more compact design, a reduction in the heat exchange area of the evaporator, and an overall reduction of materials usage, including less fin, tube and refrigerant. The reduction of tube wall thickness for the smaller diameter tube further reduced tube material. The incremental decrease in tube size reduced the estimated cost of materials by 40%, it claimed.

Taking the process further, the cooling capacity, power consumption, energy efficiency ratio, air volume and refrigerant charge were compared for the two designs, said MicroGroove. Despite reductions in heat exchange area, tube and fin materials and refrigerant volume, the product made with small tubes of copper operated at a slightly higher efficiency than similar product made with larger tubes, the MicroGroove claimed. Some modifications were made in the design and width of the plate fin. The flow path was optimised for smaller tubes in the evaporator design. The report also included an analysis of the manufacturing process and measures taken to ensure high-quality production of coils with smaller diameter copper tubes, it added.

Making concluding remarks on the study, Shunyi You, the Chief Engineer at Chigo’s Technical Centre in Foshan, and the lead author of the report, said: “With the same performance, small tube copper replaces seven millimeter copper tubes, leading to the cost reduction, so there are good expectations for the market potential. The products are sold widely abroad, including Europe, USA and South East Asia.”

More information about the design study is available online at www.microgroove.net, and for more information about heat exchanger coils made with small tube copper, readers could visit www.microgroove.net, the announcement added.