Development of a new optical method to quantify local air-side heat transfer coefficient

Min Che, Stefan Elbel

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Low air-side heat transfer coefficient (HTC) limits the performance of many heat exchangers. A new method is developed to obtain local air-side HTC of real heat exchangers without the use of complex experimental tools. The method relies on measuring mass transfer and applying the analogy between heat and mass transfer to determine heat transfer. A thin film coating is applied to the heat transfer surface which is exposed to a suitable trace gas, in this case, a 50 ppm ammonia-air mixture. The coating absorbs the ammonia and changes color. A detailed description of the new measurement technique is given, including the application of the fundamental heat and mass transfer correlations, evaluation of suitable coating formulations, determination of surface morphologies, and discussion of the optical principle to quantify color change. For laminar flow across flat plates, the new method results in experimental HTC that are within 17% of the Blasius solution.

Original languageEnglish (US)
Title of host publicationICR 2019 - 25th IIR International Congress of Refrigeration
EditorsVasile Minea
PublisherInternational Institute of Refrigeration
Number of pages8
ISBN (Electronic)9782362150357
StatePublished - Jan 1 2019
Event25th IIR International Congress of Refrigeration, ICR 2019 - Montreal, Canada
Duration: Aug 24 2019Aug 30 2019

Publication series

NameRefrigeration Science and Technology
ISSN (Print)0151-1637


Conference25th IIR International Congress of Refrigeration, ICR 2019


  • Coating
  • Color Change
  • Convection Mass Transfer
  • Heat and Mass Transfer Analogy
  • Local Air-Side Heat Transfer
  • Tracer Gas

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering
  • Mechanical Engineering
  • Condensed Matter Physics

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