Performance Improvement of Microchannel Heat Exchangers with Modified Louver Fins under Frosting Conditions

Microchannel heat exchangers (MCHX) are increasingly being used in refrigeration and heat pumps due to their superior thermal-hydraulic properties. However, when the MCHX surface temperature drops below the freezing point, frost will accumulate on the fin surface, which significantly affects the hea...

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Bibliographic Details
Published in:Applied sciences 2023-05, Vol.13 (11), p.6378
Main Authors: Xiong, Tong, Liu, Guoqiang, Yan, Gang
Format: Article
Language:English
Subjects:
Air flow
Comparative analysis
Drainage
Fins
Freezing
Freezing point
Frost
frost formation
Heat exchangers
Heat pumps
Heat transfer
Hydraulic properties
louver fins
Melting points
microchannel heat exchanger
Microchannels
pressure drop
Refrigeration
Surface temperature
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Summary:Microchannel heat exchangers (MCHX) are increasingly being used in refrigeration and heat pumps due to their superior thermal-hydraulic properties. However, when the MCHX surface temperature drops below the freezing point, frost will accumulate on the fin surface, which significantly affects the heat transfer performance. In this study, a modified MCHX with extended windward fins was developed to improve the frosting performance. The thermal-hydraulic performance of the modified MCHX and conventional MCHX were compared and evaluated under frosting conditions. Results show that the extended fins on the windward side capture a large amount of frost and delay the rapid blockage of air flow passage by frost. The modified MCHX structure makes the frost more evenly distributed. During the 60 min frosting cycle, the total heat transfer capacity and the mass of the accumulated frost of the modified MCHX are 9.6–49.7% and 10.3–46.9% higher than the conventional MCHX, respectively. Furthermore, the modified MCHX has greater potential to improve the thermal-hydraulic performance under the condition of more uneven frost layer distribution. The purpose of this work is to provide useful guidance for the optimal design of MCHX under frosting conditions.
ISSN:2076-3417
2076-3417
DOI:10.3390/app13116378