13th Confernce on the Applications of Air Pollution Meteorolgy with the Air and Waste Management Assoc
Fifth Conference on Urban Environment


ISC3 and PRIME Versus Wind Tunnel Observations for a Power Plant with Hyperbolic Cooling Towers

Ronald L. Petersen, Cermak, Peterka Petersen, Inc., Fort Collins, CO; and B. C. Cochran

This paper evaluates the validity of ISC3 and ISC-PRIME for modeling a power plant with two 130 m Hyperbolic Cooling Towers and various rectangular plant structures. When simple rectangular structures are associates with a power plant site, ISC3 or ISC-PRIME should give reasonable concentration estimates. When the structures become more complicated, porous and/or cylindrical, these models may not give accurate concentration estimates. For this site, accurate estimate were needed to ensure the appropriate stack height and emission control were selected. To meet the study objectives, a 1:600 scale model of the power station was constructed and placed in an atmospheric boundary layer wind tunnel. Wind-tunnel testing was then conducted to determine the equivalent building dimensions (EBD) for ISC3 or ISC-PRIME input. EBD are the building dimensions that should be input into ISC3 or ISC-PRIME so that accurate downwind concentration due to the structures on the site can be obtained.

During the course of the study, building dimensions were defined using both the BPIP analysis program and wind-tunnel determined “equivalent building dimensions” (EBD). ISC3 and ISC-PRIME were then run for 36 wind directions and one wind speed using both sets of building dimensions as input. The predicted concentrations were compared with wind-tunnel measurements obtained using a scale model of the facility. The results indicated that ISC3 and ISC-PRIME tend to over-predict maximum concentrations for this type of structure when BPIP generated building dimensions are used. ISC3 and ISC-PRIME with EBD inputs performed exceptionally well when compared to the wind-tunnel database and provided lower and more accurate concentration estimates than when BPIP building dimensions were input.

Joint Session 3, Building Scale Dispersion (Joint between the Fifth Symposium on the Urban Environment and the 13th Conference on the Applications of Air Pollution Meteorology with the A&WMA) (parallel with sessions 9 and J4)
Wednesday, 25 August 2004, 10:30 AM-11:45 AM

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