Heat Exchange Tube FAQ - Technical Questions Answered

Compared to traditional HFCs, low GWP refrigerants such as R290 have different thermophysical properties and lower mass flow rates. For R290 and similar hydrocarbons, we recommend groove designs with lower fin heights and optimized helix angles to maintain efficient heat transfer under reduced refrigerant charge. Kaineng's engineering team can develop custom groove profiles based on your specific low-charge system requirements. We have successfully supplied DX tubes for R290 heat pump projects with a 40% reduction in charge.

Yes, we offer several anti-corrosion treatment options depending on the application environment. For seawater or high-humidity applications, we can apply a specialized epoxy coating on the outer surface of the tube. To improve corrosion resistance in harsh water conditions, we also offer tin plating services. Please specify your water chemistry and operating conditions when inquiring, and our technical team will recommend the most suitable protective treatment.

We do not recommend direct replacement. Heat pump evaporator tubes are specifically designed for low evaporation temperature conditions (-10°C to -25°C), featuring optimized groove geometry and thicker anti-freeze walls. Standard AC inner groove tubes are optimized for higher evaporation temperatures (typically 5°C to 10°C). When used in heat pump applications, especially in cold climates, they may reduce efficiency and increase the risk of freezing.

R32 operates at higher pressures than R410A, and as a mildly flammable (A2L) refrigerant, safety considerations are paramount. For R32 heat pump systems, we recommend our specially optimized groove profiles to balance heat transfer performance and reduce refrigerant charge. The tubes are manufactured with enhanced wall thickness consistency to withstand higher operating pressures. Additionally, the groove geometry is fine-tuned according to the thermophysical properties of R32 to maximize efficiency under low ambient temperatures.

Our anti-freeze strategy combines three methods: (1) Increased wall thickness with a safety margin higher than standard AC tubes to withstand ice expansion pressure; (2) High-toughness TP2 copper material with excellent low-temperature ductility, adapting to slight deformation without cracking; (3) Groove geometry that promotes complete drainage during defrost cycles to minimize water retention. For extreme cold climate applications, we also offer enhanced wall thickness options upon request.

Currently, we specialize in producing copper tube components for heat pump evaporators, rather than complete finned evaporator assemblies. However, we can cooperate with authorized fin stamping partners to provide matched tube and fin combinations. If you require a complete evaporator coil assembly, please contact our sales team with your specifications, and we will connect you with suitable OEM partners who can manufacture complete assemblies using our tubes.

CO2 (R744) transcritical systems operate at extremely high pressures (up to 130 bar). For these applications, we recommend our thick-wall TP2 copper tubes with enhanced wall thickness. Alternatively, the highest pressure levels may require stainless steel tubes. Kairan Energy can provide both copper and customized tube solutions for CO2 systems. Please consult our engineering team for detailed material and wall thickness recommendations based on your specific operating conditions.

Yes, we offer comprehensive semi-finished processing, including CNC tube bending, end forming (reducing, expanding, flaring), drilling, punching, and brazed joint welding. We can provide complete tube assemblies according to your engineering drawings, ready for direct installation into your condensing unit. This service helps reduce your in-house manufacturing costs and quality control burden. Please share your drawings with our team for feasibility review and quotation.

Yes, we welcome small batch orders with custom specifications. For standard tube sizes, our minimum order quantity is as low as 100 kg. For custom semi-finished parts processed by bending, welding, or other operations, the MOQ depends on the complexity of the processing and setup requirements. Sample quantities (under 10 pieces) are available for certification purposes. Please contact our sales team with your requirements for a specific MOQ quotation.

TE/LE series tubes feature highly enhanced boiling surfaces (porous or structured surfaces) optimized for refrigerant-side pool boiling—ideal for R134a, R22, R1233zd, and similar refrigerants in chiller flooded evaporators. LF series tubes use rolled fin (machined fin) surfaces, designed for fluids with different wetting characteristics such as ammonia (R717), water, and glycol solutions. For refrigerant flooded evaporators in HVAC chillers, choose the TE/LE series. For ammonia industrial refrigeration or water/glycol evaporators, choose the LF series. Please contact our engineering team for detailed selection guidance.