Compact and microchannel heat exchangers: A comprehensive review of air-side friction factor and heat transfer correlations

Naef A.A. Qasem, Syed M. Zubair*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

69 Scopus citations


This review focuses on the thermal-hydraulic performance correlations for the air-side of compact and microchannel heat exchangers. These correlations are presented in tables, mainly in terms of Colburn j-factor and fanning friction factor (f), based on each type of fin arrangements with appropriate constraints including Reynolds number ranges, geometrical parameter limits, and fitting uncertainties. The correlations used for air-side arrangements of mini/micro channels, which are constructed in slabs, are the same as those used for the compact heat exchangers. In particular, these correlations are used for louver-fin, wavy-fin, offset strip-fin, and extended surfaces (plain fins and pin fins) arrangements. However, the correlations proposed for fin-and-tube (round) are only valid for the compact heat exchangers. We have also compared some correlations with the experimental data of Kays and London standard reference. Some performance correlations are generalized (as one correlation for each j- and f-factor) to represent all louver-fin types. However, other fin arrangements have distinct correlations based on their specific geometry. The most reported correlations are valid for dry fin conditions, whereas there are limited correlations devoted to wet or frost surfaces. A guideline based on this study is provided to facilitate the use of correlations for various configurations.

Original languageEnglish
Pages (from-to)555-601
Number of pages47
JournalEnergy Conversion and Management
StatePublished - 1 Oct 2018

Bibliographical note

Publisher Copyright:
© 2018 Elsevier Ltd


  • Air-side fins
  • Compact heat exchangers
  • Heat and flow correlations
  • Microchannel heat exchangers
  • f-factor
  • j-factor

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology


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