Longitudinal Heat Conduction in Finned-Tube Evaporators.
Longitudinal Heat Conduction in Finned-Tube Evaporators.
(404 K)
Domanski, P. A.; Choi, J. M.; Payne, W. V.
ARTI-21CR/605-5005-01;
Refrigeration Creates the Future. International
Congress of Refirgeration 2007, 22nd IIR. ICR 2007.
August 21-26, 2007, Beijing, China, 1-8 pp, 2007.
Sponsor:
Heating Refrigeration Air Conditioning Institute, Canada
Keywords:
refrigeration; evaporators; heat conduction;
experiments; tests; heat exchangers
Abstract:
The paper evaluates performance of finned-tube
evaporators at different refrigerant exit superheats to
assess the impact of longitudinal heat conduction on
capacity. A combination of capacity measurements
obtained from laboratory testing, the pattern of
measured return bend temperatures, and the theoretical
analysis suggests the occurrence of tube-to-tube
transfer via fins and rejects the tube longitudinal heat
transfer as the possible causes of capacity degradation.
The impact of tube-to-tube heat transfer was negligible
in tests with a uniform 5.6DGC superheat, but it was
significant in tests involving 16.7DGC superheat. The
measured difference in capacity between two evaporators
- in one of which tube-to-tube heat transfer was
prevented by cuts in common fins - was as much as 23%.
The level of capacity degradation was affected by air
volumetric flow rate.
