Performance Assessment of Energy-Efficient Ventilation in Highway Tunnels

This study investigates the integration of energy-efficient ventilation strategies for maintaining optimal air quality in road tunnels. With increasing emphasis on sustainability and the urgent need to reduce energy consumption in infrastructure systems, the research aims to evaluate and optimize tunnel ventilation by balancing pollutant control with minimal energy use. The study is designed to simulate airflow and pollutant dispersion under different traffic and environmental conditions, assess the energy consumption of conventional and demand-controlled ventilation (DCV) systems, and identify optimal control strategies that satisfy air quality standards while minimizing power usage. The methodology involves developing a threedimensional tunnel model, incorporating real-world geometry, traffic-induced emission profiles (focusing on CO and NOx), and ventilation system configurations. Different scenarios are analyzed, including fixed-speed and variable-speed fan operations, with DCV strategies implemented using pollutant thresholds to regulate fan performance. Energy demands are computed based on airflow dynamics and fan duty cycles, while the model outputs are validated against existing regulatory standards such as those set by PIARC and the World Health Organization. Results indicate that DCV strategies can reduce ventilation energy consumption by up to 35% without compromising on air quality, offering a more sustainable alternative to traditional ventilation practices. The study concludes that CFD-based evaluation offers a practical framework for the development of intelligent ventilation systems, enhancing operational efficiency and environmental performance. However, the study is limited by the assumption of uniform traffic flow and static emission profiles, and does not incorporate real-time sensor feedback, which could be explored in future work through integration with IoT-based monitoring systems. This research provides significant practical benefits by offering validated insights that support the design, retrofitting, and operation of energy-efficient tunnel ventilation systems, particularly for application in urban and congested settings where air quality and energy management are critical concerns.