Optimal adjustment of the number of air changes of a smelter pot room by using mathematical optimisation

The only large-scale, cost-effective way to exhaust contaminated air from the furnace pot room of an industrial plant is through natural ventilation. The effectiveness of the ventilation depends, amongst others, on the openings of the windows through which the air is allowed to enter and exit the workshop. The ventilation is also directly influenced by the prevailing weather outside the building. An appropriate measure that characterises the ventilation within the workshop is the number of air changes per hour, and ideally, it should be close to a prescribed value for all weather conditions. This requirement can be met by the appropriate adjustment of the opening angles of the inlet and outlet window slats. This paper reports on the feasibility of using mathematical optimisation to determine the ideal window slat angles for different prevailing wind conditions. The proposed optimisation methodology employs computational fluid dynamics software (FLUENT), coupled to a computationally economic optimisation algorithm (Dynamic-Q), to determine the optimal slat angles. Results of the successful application of the proposed optimisation procedure to an example problem of a large-scale aluminium smelter pot room are presented.A much abbreviated version of the paper was read at the WCSMO6 ISSMO Congress in Rio de Janeiro, May 2005