Are some of the reasons why aluminum coils are becoming an important trend within the HVAC sector.
by Tad Sodergren *
There are numerous reasons for the tendency to manufacture aluminum coils completely from the high cost of copper, to the lack of supply sources worldwide.
However, one of the main reasons our industry has been the new regulations. After all, the industry is headed in that direction to reasonable price stability. In addition to this trend it complies with the regulations on refrigerants. Not forgetting the success that the automotive industry has had with similar evaporative condensers in vehicles.
Let's look at history, is there anything really new?
The exclusive use of aluminum started basically in the automotive industry in the decade of the years 90. The automotive industry then faced similar challenges in manufacturing that we have today in the field of HVAC systems, for example, were forced to spend the refrigerant R-134a operating at a slightly higher pressure. Manufacturers recognize that these changes cause major challenges when designing the coils, as we also recognize that technicians and installers causes them headaches adopt new installation techniques.
The automotive industry was forced to find an alternative with two main objectives in mind: to improve performance and reduce the size and weight. As is well known, all vehicles currently use aluminum in their coils, with the technology called microchannels.
The reader may think "yes, but that happens in the business of cars." Well, if we go back a bit in time find that General Electric invented in the years 60 a coil made of all aluminum Spine Fin called, which was subsequently acquired by Trane. In fact, Trane has been successfully using coils made of aluminum since the early 70.
Due to the high cost of copper, the high pressure refrigerant and the need for improved efficiency, our entire HVAC industry is adopting use-aluminum coils.
The new coils have three components: aluminum channel, aluminum fins and two valves. The three components are welded together in an oven hydrogen / nitrogen. This ensures a better process in manufacturing the coil, compared with traditional welding the return bends and manifolds, which may involve an enormous amount of welding and subsequent increase in the leakage manufacturing process.
You need to assess the origin of the negative comments and common problems reported, which usually come from the technicians and installers, due to ignorance about the new trend.
The experts consider that all changes occurring in the industry are due to problems or equipment failures. And let's be honest, nobody likes change. But there is a lot of misinformation in the industry, starting with beliefs as "these coils are more complicated than conventional serpenties copper / aluminum" or "require a more accurate load and are prone to more repairs than conventional coils made of copper / aluminum" .
Like any conventional installation process is necessary to implement the following practices:
• Weld connections with nitrogen.
• Install a filter drier in the liquid line.
• Use the triple evacuation method.
• Balancing any additional charges.
There are also systems standardized procedures for copper / aluminum, which, generally speaking, have not changed. As to the load, less refrigerant is required. This reduces load time, but there is less room for mistakes. If you follow the manufacturer's instructions, no problem should not occur.
Another important issue is the cleanliness of the coils. If you look carefully a coil, you will see that due to the brazing process fins made all aluminum coils are much more resistant than conventional units with copper tube and aluminum fins. In a coil of copper and aluminum must use a cleaner low pressure and upward and downward movement to ensure that the fins are not bent, and so avoid causing a restriction of airflow, which causes loss of heat transfer. Environ coils with microchannel technology or completely made of aluminum are very resistant and can be washed at high pressure in any direction, allowing you to have a clean coil without using chemicals.
Finally, there is the issue of reparations. As with any other coil, always resorted to the manufacturer for any repair procedure. If the technician studies the manufacturers instructions, you should have no problem to repair aluminum coils.
In general, over the years our industry has always been changing its standards without major problems. So, we went from reciprocating compressors to scroll compressors, refrigerant R-22 to R410a. These and other changes are necessary, we should adopt to ensure a better future.
So next time someone tells you "I do not like this," make sure you do not say it just because you do not like change. Help him to understand that if we do not welcome the change we will be left behind.
* Tad Sodergren is the manager of global sales (Andean Region) Lennox. He can be reached by email