Energy 2030

Organizing Committee



Poster Exhibition 2008 Proceedings
Proceedings of the Second International Energy 2030 Conference,
November 4-5, 2008, Abu Dhabi, UAE

Performance Characterization of Two Selected Refrigerants in a Flat-Plate Micro-Tube Condenser

E. Al-Hajri

University of Maryland, USA

S. Dessiatoun

University of Maryland, USA

A. Shooshtari

University of Maryland, USA

M. Ohadi

The Petroleum Institute, UAE

This work presents a detailed characterization study of two-phase condensing flows of two refrigerants, R134a and R-245fa, in a single water-cooled micro-channel with a 0.4 mm x 2.8 mm cross-section (0.7 mm hydraulic diameter and 7:1 aspect ratio) and length of 190 mm. A single micro-channel was chosen for the study to eliminate flow mal-distribution issues commonly encountered in micro-channel banks. The experiments included a parametric study of the effects on average heat transfer coefficient and overall pressure drop of variations across the micro-channel condenser with mass fluxes between 50 and 500 kg/m2s, saturation temperatures between 30șC and 70șC, and inlet super heats between 0șC and 20șC. The inlet state was kept either at 100% quality or superheat and the outlet condition at 0% quality; these calculations were based on water-side heat rejection. Careful design and instrumentation of the test setup resulted in energy balance uncertainty within +/-11% and uncertainty of average heat transfer coefficient within +/-12%. It was determined that inlet superheat has little effect on heat transfer coefficient and overall pressure drop, but that the corresponding effects of saturation temperature and mass flux are significant.

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