Abstract
In most domestic and commercial refrigeration systems, frost forms on the air-side surface of the air-to-refrigerant heat exchanger. Frost-tolerant designs typically employ a large fin spacing in order to delay the need for a defrost cycle. Unfortunately, this approach does not allow for a very high air-side heat transfer coefficient, and the performance of these heat exchangers is often air-side limited. Longitudinal vortex generation is a proven and effective technique for thinning the thermal boundary layer and enhancing heat transfer, but its efficacy in a frosting environment is essentially unknown. In this study, an array of delta-wing vortex generators is applied to a plain-fin-and-tube heat exchanger with a fin spacing of 8.5 mm. Heat transfer and pressure drop performance are measured to determine the effectiveness of the vortex generator under frosting conditions. For air-side Reynolds numbers between 500 and 1300, the air-side thermal resistance is reduced by 35-42% when vortex generation is used. Correspondingly, the heat transfer coefficient is observed to range from 33 to 53 W m-2 K -1 for the enhanced heat exchanger and from 18 to 26 W m -2 K-1 for the baseline heat exchanger.
Original language | English (US) |
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Pages (from-to) | 1006-1017 |
Number of pages | 12 |
Journal | International Journal of Refrigeration |
Volume | 28 |
Issue number | 7 |
DOIs | |
State | Published - Nov 2005 |
Keywords
- Air
- Display cabinet
- Domestic refrigeration
- Evaporator
- Finned tube
- Heat transfer
- Improvement
- Vortex
ASJC Scopus subject areas
- Building and Construction
- Mechanical Engineering