Corrosion on HVAC equipment Causes & Remedies - PowerPoint PPT Presentation

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Corrosion on HVAC equipment Causes & Remedies
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Corrosion on HVAC equipment Causes & Remedies

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  1. Corrosion on HVAC equipment Causes & Remedies corrosion on HVAC

  2. Effects of corrosion in HVAC system • Decreasing the capacity of HVAC system • Increasing the power consumption of HVAC system • Shortening the life expectancy of HVAC system • Increasing the emission of CO2 corrosion on HVAC

  3. Decreasing Capacity • By loss of bondage between copper tube and aluminum fin. • By corrosion of the fins (reduced heat transfer area). • By pollution on the fins (reduced air flow). corrosion on HVAC

  4. Q-AIR Condenser Capacity (m3/h) (kW) 84.400 258 75.960 241 -50% -36% 67.250 222 59.080 202 50.640 183 42.200 162 25.320 111 Decreasing Capacity corrosion on HVAC

  5. Increasing power consumption Case Study corrosion on HVAC

  6. Shortening Life Expectancy corrosion on HVAC

  7. Fuel + Oxygen  CO2 + Water An increase of power consumption leads to more fuel combustion. More fuel combustion leads to more CO2 emission. Increasing CO2 emission corrosion on HVAC

  8. What is corrosion? • Chemical reaction of a metal and a non-metal, which produces a chemical compound. • Corrosion affects all types of metals, even corrosive resistant metals, over time and under certain conditions corrosion on HVAC

  9. Types of Corrosion • Galvanic Corrosion • Cause • Effect • Visual Appearance • Environmental Corrosion • Cause • Effect • Visual Appearance corrosion on HVAC

  10. Cause of Galvanic Corrosion • Two dissimilar metals (CU + Al) • Electrolyte (f.e. humidity) If any of these factors is not present, galvanic corrosion will not occur corrosion on HVAC

  11. Effects of Galvanic Corrosion • Galvanic Corrosion of the unprotected coil begins at the bi-metallic coupling between the copper tube (more noble material) and the aluminum fins (less noble material) • The result leads to dissolving of the less noble material (fin) corrosion on HVAC

  12. Visual Appearance of Galvanic Corrosion corrosion on HVAC

  13. Cause of Environmental Corrosion • Environmental Corrosion is the degradation of the metal, caused by a reaction with the environment, such as oxidation and chemical attack of the metal surface corrosion on HVAC

  14. Cause of Environmental Corrosion • Environmental Corrosion can be caused by different types of environment: • Marine NaCl • Industrial SOx NOx • Marine/Industrial NaCl SOx NOx • Urban SOx NOx • Rural H2S NHx NOx corrosion on HVAC

  15. Effect of Environmental Corrosion • The effect of the formation of a non-protective layer on the material surface. Unprotected metal will continue to react with the contaminant and corrode. • The fins will often become very brittle. corrosion on HVAC

  16. Visual Appearance of Environmental Corrosion On Aluminum corrosion on HVAC

  17. Visual Appearance of Environmental Corrosion On Copper Different colors shows different corrosion process corrosion on HVAC

  18. Visual Appearance of Environmental Corrosion On Copper corrosion on HVAC

  19. Types of Corrosion Protection corrosion on HVAC

  20. Quality standards • Neutral Salt Spray Test • Marine by ASTM B-117 / ISO 9227 / SS DIN 50021This salt spray test shows no defects after 10.000 hours.Reflecting ten years extension of life time in real life atthe sea side. • Acid Salt Spray Test • Urban by ASTM G-85 / ISO 9227 / ESS DIN 50021City life causes acid rain, Thermoguard shows no defectsafter 3.000 hours.Reflecting nine years of exposure to an urban climate. • Kesternich Test • DIN 50018 / SFW 2,0SHundred and twenty cycles or ten years of heavy pollutedsulfuric air have been a proven success for Thermoguard. corrosion on HVAC

  21. Quality standards • Abrasion Resistance Test • ASTM D 4060Desert Area. The Taber Abraser test concludes about exposure to erosive conditions like sandstorms. Thermoguard passed this test as extremely resistant to mechanical impacts. • Cycle Exchange Test • ISO 20340/BBecause of insufficient correlation between the results of salt spray tests and results in the field, exchange tests are more reliable and used. • Flexibility Test • NEN-ISO 1520 C1 / DIN 53156Metal expand and shrink by fluctuations in temperature. Flexibility is measured by Erichsen tests. corrosion on HVAC

  22. Mass loss in acetic salt spray test corrosion on HVAC

  23. Parameters effective coating • Optimal layer thickness: thick enough for a good protection and thin enough to avoid pressure drop and bridging • Negligible effect on heat conductivity • UV resistance • Minimal dirt adhesion • Superior chemical resistance • Flexible to cope with expansion and contraction • Easy application (onsite / in workshop) • Not sensitive to application conditions • Repairable corrosion on HVAC

  24. Pre-Coating • Fins are made out of aluminum sheets. • With a pre-coating those sheets are already protected by a coating before cutting • After cutting the sheets, new unprotected surfaces are created (a louvered fin has more cutting edges) corrosion on HVAC

  25. Pre-Coating corrosion on HVAC

  26. Corrosion begins here! Pre-Coating Al Corrosion begins here! Unprotected at Cutting edges Pre-Coating • Only protect part of fins: no protection on the cutting edges corrosion on HVAC

  27. Pre-Coating • Pre-coated material: epoxy • Epoxy bases pre-coating is not resistant to UV radiation, so not suitable for exposure to the sun. A condenser with pre-coated fins needs a roof to prevent decaying! corrosion on HVAC

  28. Pre-Coating • With a pre-coated fin the coating forms an insulation between the copper tube and the aluminum fin. • This decreases the heat transfer (about 5 to 7%) corrosion on HVAC

  29. Post-Coating • With a post-coating the coating is applied after full production of the coil. • No unprotected surfaces are present • All metals are protected from the environment by the post-coating • The coating forms a barrier between the metals and the electrolytes. No galvanic corrosion can occur corrosion on HVAC

  30. Protect all the area of Coil! Also Protect copper tubes of Coil! Al Double Protection Layers No open area of Al Fins and Copper Tubes Post-Coating corrosion on HVAC

  31. Post-Coating is a Poly Urethane, which gives a good resistance against UV radiation. Poly Urethanes are highly flexible to cope with expansion and contraction. Post-Coating contains aluminum pigments to increase the heat transfer through the coating. If there is a gap between the fin and the tube, this gap will be filled with the coating, due to the low viscosity. This results in: A better bonding (heat transfer) No more galvanic corrosion. Post-Coating corrosion on HVAC

  32. Minor effect on the heat transfer and air side pressure drop! Post-Coating corrosion on HVAC

  33. Post-Coating • The Post-Coating system can be applied: • In the factory • Before installation • (years) after installation corrosion on HVAC

  34. Post-Coating • High chemical resistance Acids Alkalines Salts Aromatic HydrocarbonsAliphatic Hydrocarbons Halogenated Hydrocarbons Ethers and Esters Alcohols Fuel and oil Softeners Ketones and Aldehydes Amines corrosion on HVAC

  35. Comparison Pre-Coating vs. Post-Coating corrosion on HVAC

  36. The function of an air-conditioning system is to maintain a good thermal climate and acceptable indoor air quality. Besides the corrosion problems, the units also have to deal with the growth of micro organism. Anti-Microbial corrosion on HVAC

  37. Anti-Microbial corrosion on HVAC

  38. An effective solution is applying a special designed coating that prevents growth of micro organism, such as: Bacteria Yeast Moulds Algae Anti-Microbial corrosion on HVAC

  39. By applying these special coatings, adhesion of dust, dirt and micro organism to the surface is avoided. Anti-Microbial • Anti microbial is available for all types of coatings (heat exchanger, casing, floor) corrosion on HVAC

  40. Before Anti-Microbial After corrosion on HVAC

  41. CO2 Emission Reduction • Power consumption of an unprotected system vs. post-coating corrosion on HVAC

  42. CO2 Emission Reduction • Reduction of power consumption leads to a reduction of CO2 emission. Calculation Sheet (website) Calculation Sheet (laptop) corrosion on HVAC

  43. Organization and Application Facilities corrosion on HVAC

  44. Conclusion • Unprotected coils will have a limited lifetime and decreasing performances. • Applying any kind of Corrosion protection gives a lot of advantages. • Durability of a Post-Coating is better than a Pre-coating. corrosion on HVAC