Copper Loses its Crown in the HVAC Industry
Of all the materials throughout history few have had as much of an impact as copper. Copper and tin are used to make bronze, which is so useful it ushered in the Bronze Age 6,000 years ago. Today, copper remains a very important and useful material for the HVAC industry. It is soft and ductile, yet durable enough to meet the needs of many different applications. In addition, copper is able to transfer heat very effectively making it ideal for the HVAC industry. In recent years copper’s shortcomings have been brought to light and fabricators have begun to shift away from using the material.
Drawbacks of copper
Since the early 1990s the price of copper averaged $1.25/lb., but as the demand for copper increased in the late 2000s the price rose to over $3.00/lb. These high and volatile prices can have huge implications on a business’s profit margins and have turned what was once considered a mainstay in the HVAC industry to a secondary option for some manufacturers. Although some companies choose to buy additional supplies of copper when prices are low, many companies have found it easier to simply switch to aluminum.
The switch to aluminum
Aluminum has long been used for making heat transfer components in the HVAC industry and should not be seen as being inferior to copper. There are even some applications where aluminum may be preferable over copper. Copper is susceptible to corrosion caused by formic and acetic acids commonly released by building materials, paints, and household cleaners. Aluminum is not vulnerable to this corrosion causing some manufacturers to prefer it even before the rise in copper prices. Aluminum was also used extensively in the auto industry, which spurred the invention of “life-long alloys” that could withstand the effects of road salt and other debris. The HVAC industry quickly took notice of these alloys and began using them for heat exchangers.
Cautions before making the switch to aluminum
Before you decide to switch your production to aluminum there are a few things you may want to consider.
Whether you use copper or aluminum, the material has to be compatible with the environment in which you intend to use it. Indoor HVAC applications are straightforward because indoor heat exchangers are not exposed to anything harsh and are relatively short, making expanding the tube fairly easy. Outdoor HVAC applications on the other hand, are a little more complicated. Anything acidic or caustic is corrosive to aluminum so things like saltwater from the ocean, sulfuric acid from rainwater, and sulfur dioxide from the air could pose problems. The bottom line is that the aluminum tubing has to be compatible with the fluid running through it or issues could arise.
It is also important to realize that although aluminum can be a good substitute for copper, it is not a direct replacement. When aluminum tubing is used for air-conditioning systems for example, it needs to have thicker walls than that of similar copper tubing. Many fabricators immediately assume that the added wall thickness will negate the lower cost of aluminum because more of the material is used. The walls only need to be a few thousandths of an inch thicker though, and the aluminum tubing is still less expensive and lighter with this added thickness.
Aluminum is also not as ductile as copper meaning it stretches less and is not as easy to work with. The most ductile copper alloys can stretch up to 70% before they finally fail, while some of the most ductile aluminum alloys can only elongate 27% before failing. Knowing this, it will take time for shops to adjust their production when they first switch to aluminum. Switching to aluminum use over copper will provide long-term benefits, but it may take some restructuring or learning on the part of your shop before you can truly realize these benefits.
Copper will always have a place in the HVAC industry, but many manufacturers are beginning to see the benefits of switching to a substitute such as aluminum. It is no wonder that 2012 marked the first year aluminum usage surpassed copper in the HVAC industry. These are just some of the reasons why manufacturers are looking to aluminum and things you may want to consider when making the switch. If you find aluminum to be a suitable material for your production, using it should allow you to reduce your input costs while continuing to make quality products for your customers.