Aluminium Micro-channel Tube

Manufacturing micro-channel aluminum tubes is a highly challenging process due to their high technical content. These tubes have a minimum variety width of 12mm and a thickness of only 1mm, while having 12-16 holes. The difficulties associated with their production are mainly reflected in the following six aspects.

Very large extrusion ratio : The extrusion ratio for micro-channel aluminum tubes is more than 400 times, which is beyond the limit of the aluminum extrusion process.

Ultra-high dimensional accuracy : The size accuracy requirement for micro-channel aluminum tubes is much higher than the national standards for "aluminum and aluminum alloy research to hot extrusion tube."

Gas tightness : A set of micro-channel heat exchanger has around 50-150 micro-channel aluminum tubes. Even if one tube has airtightness defects like air holes or inclusions, the entire air conditioner will be scrapped. The quality standard is measured in PPM, with the measurement standard being 15 PPM or less.

High-quality rod/bar : The thin wall of micro-channel aluminum tubes can leak if the purity of the cast bar material and hydrogen content cannot reach the requirement. Therefore, high purity refined bar with hydrogen content ≤ 0.09% must be used.

Surface zinc spraying technology : A thin layer of zinc must be sprayed on the outer surface of the micro-channel aluminum tube to protect it from corrosion. However, there is no domestic manufacturer who can provide qualified zinc spraying equipment, and only a few international manufacturers can provide it.

Online flaw detection and inspection technology : The technical difficulty of micro-channel aluminum tubes makes quality control extremely critical. It is essential to use scientific and effective online flaw detection and surface quality inspection means in the production process to timely detect (and mark) defective products.

These challenges make the production of micro-channel aluminum tubes extremely difficult, but the high performance and efficiency they offer make them a worthwhile investment.

Die design and processing technology capabilities

This capability mainly includes the ability to achieve very low extrusion breakthrough force, very high dimensional accuracy, and special molding capacity. It also includes a die design and manufacturing technology with strong wear resistance for hot extrusion, as well as die wall wear resistance and heat resistance through the use of super-lubrication technology. The single and multi-branch co-extrusion die multi-point temperature precision control technology is also a part of this capability.

Extrusion process control technology capabilities

This capability mainly includes the ability to maintain constant temperature heating of extruder die barrels, equal speed extrusion technology, and the gradient heating technology of cast bars. Additionally, it includes the porous micro ultra-thin wall balanced extrusion, thermal energy elimination, and the ability to keep all links without product deformation factors and product defects technology. The single and multi-branch product winding and rewinding device and synchronization control technology are also part of this capability.

Comprehensive use of debugging capabilities

This capability mainly includes the ability to select, modify, debug, and combine various equipment according to the product production requirements. It also includes online zinc spraying and control technology, brazing roll coating online detection, defect marking, and control feedback technology. Furthermore, it includes product uncoiling, finishing, straightening, and chipless cutting technology.

Ability of strain and rapid response

The main performance of this capability is the ability to quickly identify the root cause of various problems in the production process and provide rapid solutions and a response mechanism.

History of Refrigerant Change

In 1989, the first international agreement to restrict the use of CFCs was signed, known as the Montreal Protocol. This agreement accelerated the process of protecting the ozone layer from chemical destruction. At that time, the preferred alternative was R22, which is now commonly used in home and commercial air conditioners and other appliances.

However, the massive consumption of R22 would cause another catastrophic damage to the Earth: the greenhouse gas effect. Therefore, a ban was issued, with a 65% reduction in 2003, 35% reduction in 2010, 10% reduction in 2015, and a total ban in 2020 (later adjusted to 2030).

New, environmentally friendly refrigerants such as R134a, R407C, and R410a have been developed as replacements. R410a, with its high pressure and gas density, has become the most common refrigerant for home and commercial use worldwide.

It can be used with smaller exhaust volume compressors and smaller diameter pipelines and valves, making it an excellent choice. In fact, it was the first refrigerant to become mandatory for use in automotive air conditioning systems (EU regulations in 1996, China regulations in 2002). The parallel flow micro-channel evaporator and condenser with high pressure resistance have also become the best choice for home and commercial air conditioning systems.

Automotive air conditioners are the first to enter the microchannel era

Micro-channel heat exchangers, also known as parallel flow evaporators and condensers, were first researched by two professors at Stanford University in 1981. They began to be used in automotive air conditioning systems with the environmentally friendly refrigerant R134a in 1996. Today, all automotive air conditioning systems worldwide use micro-channel heat exchangers.

Home and commercial air conditioners are ready for development

The use of microchannel heat exchangers in domestic and commercial air conditioning systems came later on. Initially, the Japanese market was the quickest to adopt R410a, starting with small air conditioners of less than 2 hp and gradually moving to larger air conditioners. They also took measures to improve energy efficiency by expanding the heat exchange area of air conditioners to achieve high efficiency. The all-aluminum microchannel heat exchanger is undoubtedly the first choice for expanding the heat exchange area of air conditioners.

As the deadline for the ban draws nearer, more and more well-known domestic and foreign air conditioning companies have begun to develop the use of all-aluminum micro-channel heat exchangers. The United States, for instance, started using all-aluminum microchannel heat exchangers on home air conditioners nine years ago, and the U.S. air conditioning industry carrier "York" has since been using all-aluminum microchannel heat exchangers for 100% of its products. Furthermore, air conditioning production enterprises in Japan and South Korea, such as Sharp and Samsung, began researching microchannel heat exchangers several years ago.

In China, the need to replace home and commercial air conditioning systems is becoming increasingly urgent.

Firstly, China has been the world's leading producer of air conditioning units for many years, accounting for over 70% of global production. As a result, restrictions and bans on air conditioning units have a significant impact on China.

Secondly, China's national and commercial air conditioning market is highly competitive, and rising copper prices have made it difficult for companies to afford. This has forced companies to accelerate the application of new technologies, including the use of aluminum instead of copper, and the adoption of parallel flow technology to reduce costs while meeting environmental protection, efficiency, and energy-saving requirements. The cost of aluminum is only one twelfth that of copper, making parallel flow technology the logical choice for cost reduction.

Thirdly, the Chinese government has introduced a series of mandatory energy-saving policies, laws, and regulations. There are three main ways to achieve energy savings in air conditioning units: frequency control, which can increase costs; replacing refrigerants directly with R410a refrigerant, which can also lead to higher costs; and using parallel-flow micro-channel heat exchangers, which can be environmentally friendly, energy-efficient, and reduce costs by more than 50%. Therefore, micro-channel heat exchangers have become the best choice for home and commercial air conditioning replacement.

Microelectronics and other fields of application

Microelectronics is following Moore's Law in rapid development, with increasing transistor integration. As a result, high-speed electronic devices have reached a thermal density of 5-10MW/m2, and heat dissipation has become a major bottleneck in their development. To address this issue, the use of micro-channel heat exchangers to replace traditional heat transfer devices has become an inevitable trend. Therefore, in fields that rely heavily on embedded technology and high-performance computing, such as aerospace, modern medicine, and chemical and biological engineering, micro-channel heat exchangers will have broad application prospects.

Air-conditioning and water heater applications

As microchannel heat exchanger technology gradually matures, related products have emerged in the automotive and home air conditioning industries (such as in the United States). Additionally, the hot air water heater industry has also started to explore the microchannel field.

Application advantages

1,Energy efficiency is crucial for modern air conditioners. However, conventional heat exchangers can hinder the production of high-quality products that meet Grade I energy efficiency standards. To solve this issue, using a micro-channel heat exchanger is the best option.

2,Micro-channel heat exchangers provide excellent heat transfer performance for home air conditioning. When the size of the flow channel is less than 3mm, there's a difference in the gas-liquid two-phase flow and phase change heat transfer laws compared to conventional larger sizes. The smaller the channel, the more significant this size effect is. By applying enhanced heat transfer technology to air conditioning heat exchangers, making suitable changes to the heat exchanger structure, process, and air side of the enhanced heat transfer measures, the heat transfer of air conditioning heat exchangers can be effectively enhanced, improving their energy efficiency.

3,Micro-channel heat exchanger technology can be promoted in the air conditioning manufacturing and air-water heater industries, significantly enhancing the competitiveness of products and promoting sustainable development of enterprises.

Microchannel heat exchangers are superior to conventional heat exchangers. They have a small heat transfer coefficient and high heat transfer efficiency, which leads to energy efficiency and excellent pressure resistance. They can also be used for mass cooling with CO2, meeting environmental requirements. This has garnered widespread attention from academic and industrial circles both domestically and internationally. The production method of microchannel parallel flow tubes, a key technology for microchannel heat exchangers, has become mature in China, making it possible to use them on a large scale.

Aluminium micro-channel tubes have a different design and construction compared to traditional heat exchanger tubes. They have many small channels, or micro-channels, inside them which greatly increases the surface area available for heat transfer. This leads to better efficiency and performance compared to conventional tubes.

Aluminum micro-channel tubes offer several benefits in automotive applications. Their lightweight design reduces the overall weight of the vehicle, contributing to fuel efficiency and improved performance. Additionally, their superior heat transfer capabilities enable efficient engine cooling, enhancing the lifespan of the engine and optimizing its performance.

Aluminium micro-channel tubes are suitable for high-pressure applications due to their enhanced structural integrity and resistance to external pressures. This makes them ideal for use in refrigeration systems, hydraulic cooling, and other applications that require reliable performance under high pressure.

Aluminum micro-channel tubes improve energy efficiency in HVAC systems by enabling efficient heat transfer. The micro-channels provide a larger surface area, which enhances cooling performance and reduces the workload on the system's compressor. This leads to lower energy consumption and overall greater efficiency.