Water condensate retention and “wet” fin performance in automotive evaporators

Abstract

Water condensate retained inside an automotive evaporator has remained as one of the primary sources of unpleasant “odors”, which in turn can drive up the warranty cost for automotive manufacturers. The “wet” evaporator fin can also underperform due to the presence of condensate blocking the air passage. Moreover, condensate retention can be a potential factor of freezing up evaporators. Thus, an evaporator fin must be designed such that it can shed and drain water condensate as well as provide an excellent heat transfer capability. While the importance of water retention is well known, there seems lacking of a comprehensive way to evaluate the water retention characteristics of a particular product. In this work, attempts were made to answer four questions: (1) What is the mechanism that controls water condensate retention characteristics in an automotive evaporator? (2) Can different water retention evaluation methods reveal the same characteristics? (3) How and to what extent can an evaporator fin underperform due to water retention? and (4) Can we design a “better” fin to alleviate the problem? Clearly, any conclusive solutions to these challenges can lead to an efficient and more compact evaporator design, which will then be the key of cutting cost while delivering superior product performance.