In this paper, a revised method of duct design, which is based in part on the T-method of duct design, is presented. This method integrates the capital costs and fan power costs into a single life-cycle cost that is optimized for all airflow paths. A new cost factor that permits direct comparisons among all the duct sections is also introduced. An existing ducting system is used to illustrate the design methodology and the sensitivity of the life-cycle costs to each ducting section design. Depending on the overall fan efficiency, the estimated life-cycle cost savings using this optimized design methodology would be between 22% and 30% compared to an existing design.

Units: SI