The biggest short to medium term impact of corrosion on air conditioning equipment is loss of energy efficiency and hence increased running costs. The longer term impact of corrosion can include very significant energy efficiency loss as well as the total failure of individual components or the entire system.
The real cost of this corrosion is in your energy costs.
Damaged or corroded fins can lead to premature failure of other components within the system. Damaged fins on a coil can impose extra static pressure on fan motors and blades leading to overheating and or eventual failure. Corrosion can lead to less heat transfer taking place, an elevated suction and condensing temperature, leading to compressor overheating and eventual failure.
A damaged or corroded condenser coil will lead to an eventual costly component failure, but it is the cost along the way that is the real “hidden” cost. This can be as much as a 30% increase in running amps, 35% increase in power consumed and as much as 25-30% loss in cooling and or heating ability.
Heat exchanger fin corrosion might look like minor damage to the naked eye and is often disregarded with a “She’ll be right for another few years”. Yes, it probably will last a few more years but what is the real cost in increased electricity bills?
1. How does corrosion affect the capacity of my air-conditioning?
Corrosion will cause your air-conditioner to loose efficiency and capacity, which results in the air-conditioner consuming more energy and producing less cooling capacity. Your installation will therefore perform the worst when you need it the most. Heat exchangers are extremely vulnerable to corrosion due to the combination of different metals in the heat exchanger (copper and aluminum) and the continuous exposure to pollution and corrosive elements in the environment. The heat transfer between the liquid/gas medium in the tubes and the outside air passing over the fins is reduced due to the corrosion of the aluminum. In addition, the pollution on the fins will reduce the airflow through the heat exchanger significantly. To release all the absorbed heat from the air-conditioned space the system raises the condensing temperature/pressure, this results in a higher temperature difference between the gas/liquid and the outside air. This high condensing temperature/pressure is why the compressor of your air conditioner consumes more energy and often fails in the summer period.
2. What is the difference between pre-coat (epoxy, vinyl) and Blygold?
Blygold’s coating is aluminum-impregnated polyurethane, which is applied after the heat exchanger is assembled to allow for total coverage and complete penetration. Epoxy/vinyl coatings are inferior to polyurethane by their composition and the pre-coat process does not permit total coverage due to the cut edges being exposed after fabrication. Not only will pre-coat systems have a temporary effect against corrosion, they will also reduce the initial capacity by 15% due to the layer between copper and aluminum.
3. Why is my air-conditioning unit corroding?
There may be any number of reasons why your air-conditioning unit is corroding. The heat exchanger in an air-conditioner is usually made from aluminum fins and copper tubes. With these two different metals, in combination with pollution and moisture, there is a huge potential for galvanic corrosion to take place. Aluminum will corrode rapidly around the copper tubes. Other corrosive agents and pollutants in the atmosphere, like sulfur, carbon dioxide and nitrogen, are able to directly react with aluminum and copper. Huge volumes of air are forced through the heat exchangers and this means they are are exposed to far more aggressive circumstances than other equipment.