The problem…
In HVAC equipment, exposure to various elements in the environment can lead to localized and/or general corrosion of condenser, heating and cooling coils and all metal parts. Such corrosions may come from sea water influence (even in 4km distance), chemical environments, dust and extremely high or low temperatures. The use of improperly protected components in corrosive locations may lead to premature performance degradation, unsightly surface conditions and, under the most severe conditions, equipment failure, which is common in coastal and industrial area’s. These effects may be costly to the end user. Fortunately, with proper corrosion protection selection and proper maintenance, corrosion can in most cases be prevented.
The coils…
If a condenser corrodes or gets blocked, less heat transfer can take place from the refrigerant to the surrounding ambient. A galvanic corrosion process will attack the bonding between copper tube and aluminum fin, exactly at the spot where the condenser has its function.
Corroded or blocked condensers are one of the most frequent service problems in commercial refrigeration and air conditioning fields today. If less heat can be rejected to the surrounding air within an air-cooled condenser, the heat will start to accumulate in the condenser tubes. This accumulation of heat will make the condensing temperature rise. Now that the condensing temperature is rising, there will come a point where the temperature difference between the condensing temperature and the surrounding ambient (Delta T) is great enough to reject heat from the condenser.
The main objective of protecting coils against corrosion is to achieve a chemical resistant coverage between the tube and the fin, to achieve a sealing that prevents galvanic action. Any coating application must have a proven technique to achieve this bonding.
HVAC equipment consumes until 60 to 80% of the available electricity in high temperature areas. A good conservation of the coil will not only prevent early equipment depreciation, but will significantly reduce the peak levels in the energy demands during the hot season. Corrosion control and treatment are of vital concern because corrosion of equipment and primary structures has a great effect on the operational and structural integrity of systems. Economy is another basic consideration since severe corrosion will eventually weaken structural members to the point where replacement or reinforcement is required in order to sustain design loads.
In all industries and housing area’s in hot area’s , down time of heat exchangers can be life threatening or cause extreme consequential damage. Prevention of corrosion is one of the main concerns in the life cycle of HVAC equipment.
HVAC components…
Careful selection of HVAC components and especially drain pans will prevent corrosion of vital parts and contribute to a healthy indoor environment. Drain pans collect the shed off of moisture of the coils and casings. Un-drained moisture and dirt is collected and will act as a breeding nest for corrosive and infectious elements. Proper anti corrosion and anti-microbial protection will minimize mechanical failures and healthy building problems.
The conclusion…
HVAC suppliers are forced to shift their focus to the changing objectives of modern industry. Life cycle costing, safety and health and extending technical depreciation are the major selection criteria for Global HVAC users. Corrosion is the most influential factor of all three objectives in current mission statements, and will be a crucial key success factor in the HVAC supply chain.
Chrysostomos I. Bouras