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HEAT TRANSFER EVALUATION OF HFC-236FA IN CONDENSATION AND EVAPORATION
Tzuoo, S. M. AND M. B. Pate. HEAT TRANSFER EVALUATION OF HFC-236FA IN CONDENSATION AND EVAPORATION. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-98/029 (NTIS PB98-136203), 1998.
The report gives results of an evaluation of the shell-side heat transfer performance of hydrofluorocarbon (HFC)-236fa, which is considered to be a potential substitute for chlorofluorocarbon (CFC)-114 in Navy shipboard chillers, for both conventional finned [1024- and 1575-fpm (fins-per-meter)] tubes and high performance enhanced (Turbo-CII, -B, and BII) tubes. Condensation of oil-free HFC-236fa was conducted on 1024- and 1575-fpm, and Turbo-CII tubes. Pool boiling on four tube types (1024- and 1575-fpm, and Turbo-B and BII) was tested not only for pure HFC-236fa but also for HFC-236fa mixed with 1 and 3% lubricant by weight. The polyolester lubricant used has a viscosity of 340 SSU at 37.8 C (100 F) and the trade name Castrol Icematic SW-68. The above tubes, which have nominal outside diameters of 19.1 mm (3/4 inch), were evaluated at a saturation temperature of 40 C for condensation and 2 C for pool boiling over the heat flux range of 15 to 40 kW/ sq m. Heat transfer was improved for HFC-236fa by using the high performance enhanced tubes. Specifically, the Turbo-CII tube performed better than the two conventional finned tubes in the condensation testing, while the performance of the Turbo-B and BII tubes was superior to the two conventional tubes in the pool boiling testing.