Performance evaluation of parallel flow microchannel heat exchanger subjected to external heat transfer

B. Mathew, H. Hegab

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

4 Citations (Scopus)

Abstract

In this paper the effect of constant external heat transfer on the performance of a two fluid balanced parallel flow microchannel heat exchanger is analyzed. A mathematical model is developed for predicting the effectiveness-NTU relationship of both the fluids. Theoretical analysis is presented for various cases of external heating over a wide range of NTU. External heating improved the effectiveness of the cold fluid but degraded the effectiveness of the hot fluid while external cooling produced the opposite changes in the effectiveness of the coolants. The extent of improvement or degradation depended on the level of external heating/cooling. A term referred to as performance factor is used to assess the degree of improvement or degradation of the effectiveness of the individual fluids. Experiments conducted on two microchannel heat exchangers by subjecting the coolants to 5% and 10% external heating have been presented in this paper. The experimental value of NTU varied from 0.42 to 1.76. Good agreement is observed between the theoretical predictions and experimental results. The results presented in this paper are nondimensional; thus they can be utilized irrespective of the dimensions of parallel flow microchannel heat exchangers as well as the type of coolant.

Original languageEnglish
Title of host publicationHeat Transfer, Fluid Flows, and Thermal Systems
PublisherAmerican Society of Mechanical Engineers (ASME)
Pages941-950
Number of pages10
ISBN (Print)0791843025, 9780791843024
DOIs
Publication statusPublished - 2008
Externally publishedYes
EventASME International Mechanical Engineering Congress and Exposition, IMECE 2007 - Seattle, WA, United States
Duration: Nov 11 2007Nov 15 2007

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings
Volume8 PART A

Conference

ConferenceASME International Mechanical Engineering Congress and Exposition, IMECE 2007
Country/TerritoryUnited States
CitySeattle, WA
Period11/11/0711/15/07

Keywords

  • Effectiveness
  • External heat transfer
  • Heat exchanger
  • Microchannels
  • NTU

ASJC Scopus subject areas

  • General Engineering
  • Mechanical Engineering

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