Underground cycle lanes system : services design

Abstract

In this dissertation, a methodology was developed to design a ventilation system for an underground tunnel to be used a cycle path. Temperature and humidity were calculated along the tunnel, considering the sensible and latent loads due to the cyclist metabolism, sensible loads due to the lighting equipment and water infiltration from the tunnel wall surface. Different ventilation layouts were used to calculate the energy consumption required to have good air quality along the tunnel. Operational cost for such ventilation layouts were calculated and a life cycle cost analysis for each layout was performed to select the most feasible layout with the highest net present value. It was concluded that the ventilation layout in a tunnel mainly depended on the outdoor environment and water infiltration. The use of different layouts operating seasonally resulted in the lowest yearly operational cost of €90,580.30 and lowest net present value after the lifetime of the ventilation system. An economic analysis including the cost for construction of the 2km tunnel, equipment costs, maintenance costs, external costs(benefits) and other expenses, with an initial capital cost €4,330,000, payback period would be just after 9 years. Therefore, such tunnels used as a cycle path would be a feasible solution in Malta. Carbon dioxide emissions would be reduced by more than 75%.