Pollution-cost balance in road tunnel ventilation

AbstractThe increasing complexity of road tunnels, coupled with increasing demands for cost effective operation, favours automated methods of selecting fan settings for ventilation control. Implications of conflicting demands for pollution control and cost control are discussed and a method of expressing them in a single parameter is introduced. First, two indices are derived, one for pollution and one for cost. Next, the indices are combined to yield a penalty factor whose value defines the level of acceptability of the tunnel conditions, allowing for future conditions as well as instantaneous ones. The method of combining the indices can be influenced by tunnel operators, both off line and on line. Examples are presented to illustrate the consequences of alternative choices of penalty factors.