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Effect of anodizing on aluminum heat emissivity or absorption

2003

I've built several aluminum air to air intercoolers (IC) to be used to cool the hot, compressed intake charge in a turbocharged automotive application. The IC looks, works and is constructed very similarly to a car radiator (lots of thin internal & external aluminum fins.) Hot, intake air under pressure is run through the IC core, the heat in the compressed air is supposed to transfer to the walls of the IC, and from there, then dissipated by the IC's external cooling fins to the atmosphere.

The IC could be left bare, and installed as is, but I would like to consider anodizing or painting or otherwise coating the IC at least externally, and possibly internally (anodizing my be the only alternative internally) to: (1) Protection from external (e.g., road salts, grime etc.) & (2) Possibly protect or improve the internal transmissivity of the cores internal fins, if that's possible. Internally, cores can be exposed to some contamination from oil blow at turbocharger bearings; (3) Externally, if anodized or painted black, to provide some visual cosmetic concealment.

I'm concerned about adversely affecting the IC's ability to transfer heat. Can someone tell me if anodizing aluminum reduces its ability to absorb then transfer heat? Should the loss (or gain) in emissivity from anodizing be regarded as significant? Is there a particular recommendation for this application?

Thanks,

Mike Pederson
- Denver, Colorado, USA