Aluminum foil for fin stock is a key component of air conditioning heat exchangers. Its core function is to achieve cooling or heating through efficient heat conduction. Aluminum is an ideal heat exchange material due to its low density, excellent thermal conductivity (thermal conductivity coefficient is about 237W/(m・K)), easy processing and environmental protection. Aluminum coil AC is mainly used to make heat exchanger fins, which improves heat exchange efficiency by increasing the heat dissipation area.
Common alloys include 1100, 1200 and 8011. Among them, 8011 alloy has outstanding comprehensive performance, combining strength and corrosion resistance. It is widely used in food packaging, electronic shielding and other fields. In air conditioners, the performance is further optimized through surface treatment.
The tensile strength, elongation and cupping value of aluminum foil need to be balanced to adapt to different stamping processes. For example, the stretching die requires a higher elongation of the aluminum foil (H22 state), while the non-stretching die focuses more on strength (H26 state). In the current industry standards, the H24 state (semi-hard state) is the most commonly used.
The thickness of aluminum foil for air conditioner fins is mostly concentrated in 0.09-0.15mm, and the width is customized according to equipment requirements, with a common range of 500-800mm. The coated aluminum foil must meet the flatness of the plate shape (≤20-40I) and coating uniformity. The coating thickness of hydrophilic aluminum foil is usually ≤3μm, and it must pass strict standards such as alkali resistance (20% NaOH solution soaked for 3 minutes without blistering) and salt spray test (500 hours without corrosion).
Hydrophilic aluminum foil has been treated with surface coating to significantly improve the performance of air conditioners and has become the mainstream choice in the industry:
The hydrophilic coating makes the condensed water contact angle α<10° (initial state), and the water droplets are easier to spread and flow down along the fins, avoiding "water droplets bridging" to block the air duct. Experimental data show that the use of hydrophilic aluminum foil can increase the heat exchange efficiency by 10%-15%, and save about 8% energy at the same cooling capacity.
Modern hydrophilic aluminum foil usually has both hydrophilic and corrosion-resistant properties. Its coating can resist the erosion of the high-salt environment in coastal areas, while its moisture and heat resistance ensures that it will not mold or odor in long-term use, improving indoor air quality.
Some hydrophilic aluminum foils use self-lubricating technology, eliminating the lubricating oil and subsequent cleaning steps in the traditional stamping process, reducing the use of harmful substances such as trichloroethylene, and conforming to the trend of green manufacturing.