OTEC Performance Tests of the Carnegie-Mellon University Vertical Fluted-Tube Condenser

摘要

Results of performance tests on a vertical fluted-tube condenser designed by Carnegie-Mellon University are reported. The condenser was free of operational problems and performed in a stable and repeatable manner. At nominal design conditions (a heat duty of 3.2 million Btu/hr and a water flow rate of 3200 gpm), the overall heat transfer coefficient (U sub 0 ) was 1040 Btu/hr.ft exp 2 . exp 0 F and the water-side pressure drop was 3.3 psi. Varying the quality of the ammonia vapor feed to the condenser (in the range of 90 to 100%) did not affect performance. On the other hand, when the heat duty was increased from 2.3 million to 4.0 million Btu/hr, U sub 0 rose from 1024 to 105 Btu/hr.ft exp 2 . exp 0 F. This trend resulted from an increase in the ammonia-side coefficient (from 3270 to 3730 Btu/hr.ft exp 2 . exp 0 F) over this range of heat duties. Finally, the water-side coefficient was about 2.45 times greater than that calculated from the Sieder-Tate equation for smooth circular tubes of the same cross-sectional area. This enhancement ratio of 2.45 was some 20% greater than the enhancement factor of 2.07 expected from the increase in surface area alone. (ERA citation 05:004223)