Aluminum Foil for Air Conditioner Condenser and Flexible Duct

Air conditioning condenser

The core function of the air conditioning condenser is to achieve heat exchange between the refrigerant and the outside air through the aluminum foil fins. This requires the aluminium condenser coil to quickly transfer heat. At the same time, it needs to withstand extreme temperature fluctuations from -40℃ to 120℃ and maintain stability under long-term corrosion by refrigerants (such as R410A). In terms of mechanical strength, the aluminum foil needs to withstand a tensile strength of ≥80 MPa to cope with stamping deformation during fin processing.

Hydrophilic coating is the standard configuration of aircon aluminum foil for condensers. Its thickness needs to be controlled at 0.5-1.5μm. It adopts acrylic resin-based formula to ensure that the contact angle is ≤10°, so that the condensed water can flow away quickly and avoid the "water bridge" phenomenon affecting the heat exchange efficiency.

Some high-end products use nano-ceramic coating, which increases the corrosion resistance by 3 times and increases the thermal conductivity to 180 W/(m·K). In addition, to prevent the coating from falling off during welding, primer pretreatment is required, and epoxy resin primer is often used to enhance adhesion.

The mainstream alloy is 8011-O aluminum foil, with Si content of 0.5-0.9% and Fe content of 0.6-1.0%. The hardness is controlled at HV30-40 through annealing process, taking into account flexibility and collapse resistance. For high humidity environment, 3003-H14 alloy (containing 1.0-1.5% Mn) is better, and its salt spray corrosion resistance can reach 500 hours without white rust, which is suitable for coastal areas.

Flexible duct

The ventilation hose adopts double-sided aluminum foil + glass fiber cloth composite process, the thickness of the aluminum foil is 0.05-0.1mm, and the surface is coated with phenolic resin to enhance tear resistance. For high temperature environment, the inner layer adopts ceramic fiber coating, which is resistant to temperature up to 1000℃, and the outer layer is covered with polyimide film to achieve double protection. The coating adhesion needs to pass the cross-cutting test (ISO 2409), and the peel strength is ≥5N/cm.

The aluminium foil flexible duct prefers 1100-H18 alloy, with a purity of ≥99.0% and an elongation of ≥20%, which is suitable for high-frequency bending. The embossing process is used in the manufacturing process to form a diamond pattern with a depth of 0.1-0.3mm on the surface of the aluminum foil, which increases the number of folding resistance to more than 1,000 times. For high-pressure systems, 5052-H32 alloy (containing 2.2-2.8% Mg) is widely used, with a yield strength of ≥195 MPa and can withstand a working pressure of 1.5 bar.

Developing trend

1. Using ultra-thin aluminum foil technology (thickness ≤ 0.03mm), the weight of the condenser fins is reduced by 30%, and water-based coatings are used instead of solvent-based coatings, reducing VOC emissions by 90%.

2. The composite rolling technology combines the aluminum foil with the copper layer, increasing the thermal conductivity to 220 W/(m·K), but the cost only increases by 15%. The laser drilling process processes 0.1-0.3mm diameter micropores on the surface of the aluminum foil, which increases the air permeability of the ventilation hose by 40% while maintaining structural strength.