In this study, the air-side heat transfer characteristics of microchannel heat exchangers (MCHXs), with enhanced shapes as condensers in refrigerators, are investigated. The heat transfer performances of flat-type, U- and V-shaped MCHXs, and conventional spiral fin-tube heat exchangers were measured and compared at various air flow rates and inlet temperatures. Furthermore, the Colburn j-factor and friction factor of the MCHXs were analyzed as a function of the Reynolds number. The second-type volume and area goodness factors were also analyzed to compare the heat transfer performances of the MCHXs considering various design parameters. Additionally, the empirical correlations of the Colburn j-factor and friction factor for U- and V-shaped MCHXs were developed using dimensionless parameters that reflect geometric and operating conditions. Hence, a U-shaped MCHX with a longer tube length was recommended to obtain a high absolute heat transfer rate, while a flat-type MCHX was recommended to realize high compactness and heat transfer efficiency.
|International Journal of Heat and Mass Transfer
|Published - 2021 Sept
Bibliographical noteFunding Information:
This study was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government ( MSIT ) (No. NRF-2020R1A5A1018153 ).
© 2021 Elsevier Ltd
- Colburn j-factor
- Friction factor
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanical Engineering
- Fluid Flow and Transfer Processes