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The effects of external corrosion protection methods on the thermal-hydraulic performance of aluminum microchannel heat exchangers.

Number: 2269

Author(s) : WANG Y., ZHAO H., HRNJAK P.

Summary

Aluminum microchannel heat exchangers are widely used in heating and cooling applications owing to their superior thermal performance and lightweight structure. The various working environments impose challenges on the corrosion resistance of the heat exchangers. Applying coating on the external surface of the heat exchangers has been one of the common methods to enhance their resistance to external corrosion. This paper presents the effects of corrosion simulated by an accelerated corrosion test on the thermal-hydraulic performance of three otherwise identical brazed aluminum heat exchangers with different surface treatments: the first heat exchanger with no treatment; the second with an organic electrophoretic coating (E-coating); and the third with conversion coating by a trivalent chromium process (TCP). The mass and thermal-hydraulic performance of the heat exchangers are evaluated before and after the exposure to a ten-day laboratory cyclic salt fog corrosion test. The result shows that due to the relatively thicker E-coating film, the initial performance of the E-coated heat exchanger is inferior to both the uncoated and TCP-coated heat exchangers. After the ten-day corrosion test, it is visually observed that the E-coating provides better protection to the heat exchanger than the TCP coating in the salt fog environment. No visible geometric deformation and fin-tube debonding are observed on the E-coated heat exchanger, while the uncoated and the TCP-coated heat exchangers show a certain level of deformation and fin-tube debonding. After the corrosion test, the uncoated heat exchanger shows a large performance degradation: the airside pressure drop increases by up to 13% and the UA decreases by up to 74% with the same frontal air velocity. The TCP-coated heat exchanger shows no significant change in airside pressure drop but an up to 61% decrease in UA. The E-coated heat exchanger shows very little change in performance after the current corrosion test.

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Pages: 9 p.

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  • Original title: The effects of external corrosion protection methods on the thermal-hydraulic performance of aluminum microchannel heat exchangers.
  • Record ID : 30030636
  • Languages: English
  • Subject: Technology
  • Source: 2022 Purdue Conferences. 19th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2022

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