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
tad.sodergren@lennoxintl.com
Author: Latin Press

Comments

saul saw Marquez
# saul saw Marquez 08-04-2015 14:52
Good morning,

True coils microchannels are more efficient heat transfer and airflow. But in cities like Barranquilla where the salt is very high, these coils do not last more than one or two years, thus reducing the useful life of equipment and increasing high operating costs thereof.

Cordially,
Ing. Saul Sierra Márquez
Air Ambiente SA
Rafael Gandia
# Rafael Gandia 16-04-2015 07:58
Good morning,
My beginnings were in the air conditioning in the automotive, met coils of copper-aluminum and aluminum subsequently all micro channels and the difficulty occurred to repair the comments in the article, we deny that technological advancement. Bouquet and then change me involved with residential and industrial air conditioning, I live in Valencia, Spain and all equipment installed on the beach have the problem mentioned by Mr. Sierra, without proper maintenance, deteriorate.
The theme of saltpeter is a problem that affects not only the coils, affects machines in general. When they do not have adequate protection, epoxy paint, electronic boards varnished with protective film serpentines, etc. saltpeter, without proper maintenance intensive and drastically reduces the lifetime of the machines.
About coils, we can not say that a coil of aluminum lasts less than equivalent copper-aluminum as both, I repeat, without proper maintenance, even wearing protective layer (film) or sacrificial layer, they deteriorate starting with the finned and in both cases is aluminum.

Best regards.
Rafael Gandia
technical department.
Mitsubishi Electric
JOSE PARRA
# JOSE PARRA 06-05-2015 19:10
According to you mr. rafael, the coils must have special treatment when severe will operate in areas such as coastal areas and beaches, is only apply proper installation techniques or design. we must move forward with technology and challenges of the transformation and evolution of the new century tecnoliga.
regards
jose parra.
INDUSTRIAL AIR CA
Alfredo Diaz G
# Alfredo Diaz G 07-05-2015 15:27
The numbers do not lie. The electrochemical potential of the aluminum and copper used in intercambiadore s heat (coils) have different values ​​and therefore there will be galvanic corrosion. Such corrosion is accelerated when a medium (water and electrolytes, as happens in coastal locations).
A finned coil and the same material (copper-copper or aluminum-tube alumin io), you will have less corrosion than a copper-aluminum coil.
The cost of raw material and avanze technology make it possible that today the industry is oriented to aluminum aluminum coils.
Lower weight, greater heat transfer in less than a conventional coil make these coils are attractive area.
Results will vary depending on the quality of the manufacturer and of the application which are to be used coils.
Alfredo Diaz
Lennox
Ricardo Walter
# Ricardo Walter 20-02-2017 21:27
That's right, in that sense and in line with the technological advances and changes that portend greater efficiency in the operation of these units, (Condensing AND / OR Evaporators), I invite you also to laboratories chemicals used in the protection of these Aluminum equipment for the creation of a special additive that could protect and increase the life span of est5as Units.
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