Revision of Threshold Luminance Levels in Tunnels Aiming to Minimize Energy Consumption at No Cost: Methodology and Case Studies

Abstract

Because of the absence of lighting calculation tools at the initial stage of tunnel design, the lighting systems are usually over-dimensioned, leading to over illumination and increased energy consumption. For this reason, a fine-tuning method for switching lighting stages according to the traffic weighted L20 luminance is proposed at no additional cost. The method was applied in a real –case scenario, where L20 luminance of the access zone at eleven (11) existing tunnels was calculated. The traffic weighted method of CR14380 was used in order to calculate the actual luminance levels for the entrance zone. The new transition zone, which decreases luminance curves, was produced and compared with the existing ones. Thus, a new switching control was proposed and programed for the Supervisory Control and Data Acquisition (SCADA) system of the tunnel. The signals of the corresponding eleven L20 meters for a period of eight days were used and the corresponding annual energy consumptions were calculated using the proposed switching program for each tunnel. The results were compared with a number of scenarios in which the existing lighting system was retrofitted with Lighting Emitting Diodes (LED) luminaires. In these scenarios, the new luminaire arrangement was based not only on the existing luminance demand value for the threshold zone, but also on the newly proposed one with two different control techniques (continuous dimming and 10% step dimming). The fine-tuning method for switching resulted in energy savings between 11% and 54% depending on the tunnel when the scenario of the existing installation at no extra cost was used. Energy savings, when LED luminaires were installed, varied between 57% (for the scenario with existing luminance demand value for the threshold zone and 10% step dimming) and 85% (for the scenario with the new calculated luminance demand and continuous dimming).

Energy Poverty and Low Carbon Just Energy Transition: Comparative Study in Lithuania and Greece

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Conceptual steps to minimize energy consumption of exterior lighting in Greece: The role of façade and road lighting

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Reliability Enhancement Driven by ANN for Lighting Control System in Highway Tunnels

“…Depending on the edge computing of CAN bus LAN, this proposal ensures tunnel lighting remains under control even if the backbone network is disconnected. Lambros T. Doulos et al [24] conducted a creative research project aimed to minimize energy consumption at no cost, this method solved the problems of over-illumination and increased energy consumption due to absence of lighting calculation tools in the initial tunnel design. Combined with the weighted L20 method, this new switching control achieved an average energy saving of 31% for 11 existing tunnels; if LED luminaries are used, this average rises to 62% for the threshold zone.…”