Energy saving in road tunnels by means of transparent tension structures

Abstract

Abstract. The high and constant rate of energy consumption in road tunnels has led researchers to look for more and more efficient lamps and luminaries. The solutions developed have partially contributed to energy saving but consumption is still high, specially in the threshold zone which requires very high levels of luminance, and the solutions found still have important contras like colour performance. In this work, we present a completely different solution: the extension of the "threshold zone" out of the tunnel by means of a transparent tension structure to let visible solar radiation go into the tunnel and achieve the required levels of luminance during daytime without any kind of electrical lighting.

A computational method to optimize energy savings of tension structures set in road tunnels

“…Figure 1 shows the modelled sun trajectory for an arbitrary tunnel. The modelled tunnel and the tension structure have been the same used for real measurements in previous works [3,4]. The tunnel is located in Granada.…”

“…Finally, we have simulated the tension structure in the gate of the road tunnel. As mentioned, it is also the same we used for the measurements in [3,4]. The simulation is shown in figure 3.…”

“…In previous works [3,4], we demonstrated that implementation of transparent tension structures in the portal of road tunnels could be a very effective an easy measure to use the sunlight during daytime, which is the most critical period of the day when dealing with tunnel lighting. Nevertheless, the advances above were carried out with very simple tension structures because the target was to prove whether they were reliable and profitable.…”

Application of semitransparent photovoltaics in transportation infrastructure for energy savings and solar electricity production: Toward novel net‐zero energy tunnel design

“…i) The threshold zone is displaced outside of the tunnel where the transparency of the structure can effectively ensure the luminance requirements are met with the use of filtered, natural sunlight. [7][8][9][10][11][12] ii) The structure acts as a type of sun-shade, reducing the veiling luminance (L seq ) and therefore the luminance required in the threshold zone. 7,13 Point ii) is especially relevant for the tunnel in this study because it is oriented along the east-west axis, bringing sunlight directly into the line of sight of drivers in the mornings and evenings, causing disability glare.…”

“…The application of sunscreen structures to reduce energy consumed by tunnel lighting systems is widespread. Researchers have tried to reduce energy consumption and daytime lighting loads using sunscreen structures using two general methods: i)The threshold zone is displaced outside of the tunnel where the transparency of the structure can effectively ensure the luminance requirements are met with the use of filtered, natural sunlight ii)The structure acts as a type of sun‐shade, reducing the veiling luminance (L seq ) and therefore the luminance required in the threshold zone …”