Heat Exchange Tube FAQ - Technical Questions Answered

Internally grooved tubes are typically 10-20% more expensive than smooth tubes of the same diameter and wall thickness. However, because they provide 30-50% higher heat transfer efficiency, you can use fewer tubes or a smaller heat exchanger to achieve the same thermal performance, potentially reducing overall system costs. The return on investment is particularly attractive for high EER and inverter AC products.

R32 operates at higher pressures than R410A and R22. For R32 applications, we recommend optimized groove designs with slightly increased fin height and modified helix angles to enhance heat transfer while maintaining mechanical strength under high pressure. Kenergy has developed specific R32-optimized tube designs, verified through extensive testing.

Yes, with specific design considerations. CO₂ transcritical systems operate at extremely high pressures (up to 130 bar). We offer enhanced internally grooved tube designs for CO₂ applications, with thicker walls and groove geometries. These tubes are made from high-strength copper alloys to ensure safe and reliable operation under transcritical conditions.

For standard sizes and groove patterns, our minimum order quantity is typically 500 kg per specification. For custom groove designs or non-standard diameters, the MOQ is 1000 kg. Sample quantities (under 50 kg) are available for qualification testing and prototype development. Please contact our sales team with your specific requirements for detailed MOQ information.

Smooth tubes are typically 10-20% cheaper than internally grooved tubes of the same diameter and wall thickness. For applications with moderate heat transfer requirements, smooth tubes provide a more economical solution without compromising system performance. For high-efficiency applications, we recommend evaluating the overall system cost-effectiveness, as internally grooved tubes can reduce the size and material usage of heat exchangers.

Our coil products are wound on sturdy steel spools with proper tension control to maintain coil integrity. Each coil is secured with multiple circumferential straps and wrapped with moisture-proof polyethylene film and woven fabric. The spool design supports the coil weight and prevents deformation during handling and transportation. For large coils, we use wooden frames or pallets to provide additional protection.

Our internal wall residual carbon content is controlled at ≤0.02 g/m², which meets industry standard requirements for AC applications. This low residual level prevents capillary tube blockage and ensures long-term system reliability. For applications requiring stricter control, we offer enhanced cleaning processes upon request, achieving ≤0.01 g/m².

Yes, we offer customized non-standard outer diameters to meet specific application requirements. Custom sizes may require specialized tooling and are subject to minimum order quantities. Please provide your desired diameter, wall thickness, and tolerance requirements to our engineering team, and we will evaluate feasibility and provide a quotation. Typical lead time for custom sizes is 3-4 weeks.

In a dry expansion evaporator, refrigerant flows inside the tube and gradually evaporates along the tube length. The groove design must promote nucleate boiling while handling two-phase flow and increasing vapor quality. In contrast, a flooded evaporator has refrigerant on the shell side and water inside the tube, requiring enhanced boiling on the outer diameter. DX tubes focus on internal groove optimization for flow boiling, while flooded tubes typically have external enhancement for pool boiling heat transfer.

Our tubes have tight wall thickness tolerances of ±0.02 mm, ensuring uniform expansion into the tube sheet without excessive thinning or cracking. Consistent bottom wall thickness across the entire tube circumference and length guarantees a reliable mechanical rolled joint. For high-pressure applications, we recommend our O-annealed tubes, which provide optimal ductility for expansion. The groove geometry is designed to maintain structural integrity during expansion without groove collapse.