Development of New Accelerated Corrosion Test(s) for All-Aluminum MicroChannel and Tube and Fin Heat Exchangers-PartⅠ: Comprehensive Literature Review

摘要

An exhaustive and comprehensive literature search was done on various laboratory testing methods to assess performance of all-aluminum microchannel heat exchangers and tube and fin heat exchangers. Cabinet style and electrochemical accelerated corrosion testing methods as well as less common corrosion tests are reviewed and attributes of each group of testing methods are provided. Literature review revealed that test parameters used in most accelerated corrosion tests such as temperature, concentration of corrosive agents, and relative humidity are intentionally selected to duplicated the most aggressive environments. The idea is that if a heat exchanger can survive harsh corrosive environment, it can survive milder environments. Among the standard test protocols the tests most used are Sea Water Acid Accelerated Test (SWAAT)] and Copper Accelerated-Acid Salt Spray Test (CASS). SWAAT appears to be used most in North America and Europe, while CASS is more popular in Japan. Currently, there is no test method that includes impact of operational parameters such as duty cycle on corrosion of heat exchangers. Heat exchanger manufacturers perform their propriety corrosion test protocols which makes performance comparison of various products impractical. It was concluded that electrochemical testing used in the past utilizes corrosion potential that is a thermodynamic parameter and does not provide any insight in the kinetics of corrosion therefore the parameter has a very limited use for HVACR industry. Newly designed accelerated corrosion test should have a well defined and measurable parameter resulting in an unambiguous characterization of the system being tested. Part Ⅱ of this work will focus on ISO 9223 standard (Corrosion of metals and alloys - Corrosivity of atmospheres - Classification, determination and estimation).