Advanced dry-cooling demonstration: Summary: Final report

An ammonia phase-change dry cooling system of increased thermal performance for electric power stations was investigated. It features the potential for significant cost savings over conventional dry cooling plants. Economic optimization studies indicate a 58% PWRR reduction from the dry-closed water loop which translates into a 4.4 mills/kWh savings over the plant life. The initial feasibility of the phase-change concept, including improved heat transfer technologies, was successfully demonstrated with a pilot plant (0.3 MWe) designed, built and operated by Union Carbide Corporation-Linde Division. It features Union Carbide's doubly enhanced condenser/reboiler, having a porous boiling surface (High Flux) on the ammonia-side, a thin film condensing promoter on the steam-side, and an air-cooled ammonia condenser utilizing Curtiss-Wright shaved fin extruded aluminum tubing. Overall heat transfer coefficients ranging from 1000 to 1440 Btu/h ft/sup 2/ /sup 0/F were measured at an ammonia flow rate of 1 gpm/tube in the condenser/reboiler and 7.0 to 8.6 Btu/h ft/sup 2/ /sup 0/F in the Curtiss-Wright condenser. Pilot plant tests with a water-deluged Hoterv plate-fin/tube ammonia condenser demonstrated heat transfer enhancements four times that over its dry operation. Union Carbide subsequently participated with Battelle (PNL) in the design, construction and testing of a 15 MWe ammonia phase-changemore » dry/wet cooling demonstration plant. The development of this facility was based on the design criteria and operating experience established from the pilot plant. The operation of the ACT system has been smooth and controllable with predicted performance of the key components achieved, thus demonstrating the feasibility of the ammonia phase-change concept on a scale larger than the pilot plant. 19 refs., 8 figs., 4 tabs.« less