Heat Exchange Tube FAQ - Technical Questions Answered

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.

Oil accumulation on boiling surfaces can significantly reduce heat transfer performance. Our enhanced surface structures are designed with optimized pore/fin geometries to promote bubble nucleation and fluid agitation, which helps continuously disrupt and displace the oil film. For systems with high oil circulation rates, we recommend regular maintenance and can provide surface treatment options to improve oil resistance. Additionally, proper system oil management and separator design are important complements to tube surface design.

Our TE/LE series porous structures are metallurgically bonded to the base tube through a high-temperature sintering process, ensuring excellent adhesion. Under normal operating conditions with clean fluids, the porous layer will not separate or clog. The service life typically exceeds 15-20 years, matching the design life of the chiller itself. In systems with excessive contamination or particulate fouling, periodic chemical cleaning can restore performance without damaging the enhanced surface. We recommend following standard water treatment and maintenance practices.

Yes, Kenergy's engineering team offers comprehensive technical support, including tube bundle layout design, heat transfer area calculation, and performance prediction for flooded evaporator applications. We can provide recommendations on tube pitch, bundle geometry, and surface structure selection based on your specific operating conditions, refrigerant type, and capacity requirements. Please share your design specifications with our team, and we will provide a detailed selection report and performance estimate.

Since the condensation HTC is improved by 40-60%, the required heat transfer surface area can be reduced by about 30-40% compared to a smooth tube condenser. This directly translates to a condenser shell that is approximately 30-40% shorter for the same number of tubes, or a smaller shell diameter with fewer tubes. The typical overall volume reduction is 25-35%. For new projects, this means significant savings in material costs, refrigerant charges, and footprint. For retrofit projects, finned tubes can increase capacity without replacing the existing shell.