Customers from different parts of the world have voiced concerns about galvanic corrosion in their units. Corrosion is an issue, particularly in hot and humid climates, when aluminium tubes are used together with conventional brass flare nut connections – two materials with different electrical potential – and then moisture is added to the mix.
The solution is simple: Keep the moisture away and there will be no corrosion.
This is achieved by covering the finished connection with a heat-shrink sleeve.
Hydro has responded to the customer issue by extensively testing the solution, exposing the materials and connections to more than 1,000 hours of Sea Water Acetic Acid Testing (SWAAT) at its in-house laboratory in Norway. The tubes utilized the HyLifeTM aluminium alloy that the company has developed specially for HVAC applications.
The results of the testing were positive, with the aluminium tubes for connecting line applications exhibiting high corrosion resistance. The test results and conclusions are available on Hydro's precision tubing website: http://www.hydro.com/en/Subsites/Hydro-Aluminium-Precision-Tubing/HVACR/
In addition, Hydro and other industry segment companies have produced comprehensive material to guide the installation of aluminium tubes in line sets. These measures assure trouble-free and maintenance-free connection of the tubes to heat exchangers and compressors. Hydro guarantees the tubes when the installation guidelines are followed.
More aluminium
Traditional users of copper tubes are increasingly turning to aluminium because of the high relative price of copper. Furthermore, copper prices are expected to remain high, with an ever-widening gap to aluminium.
Air-conditioning line set manufacturers have been replacing copper with aluminium at a steady pace, similar to other heating, ventilation, air conditioning and refrigeration segments.
As an example, original equipment manufacturers in the residential air-conditioning segment are using aluminium tubes in the actual heat exchangers – replacing copper. Aluminium had previously been used as fin material only. Using similar materials with the same electrical potential means the fins are no longer sacrificial, and that the design no longer contains a built-in loss of performance.
SIMPLE: When moisture is kept away, no corrosion will occur.
