Tunnel Lighting Research Articles

A Case Study for Tunnel Lighting Lifetime Account

A lighting device is required to provide minimum lighting level during the operating time. Contamination on lighting device causes luminous flux to be lost in lamp and structural imperfections to be formed on the surface of optical elements. This deficiency in the performance of lighting makes maintenance of lighting devices necessary. This effect formed by the common effect of various parameters and implemented periodically is called maintenance factor. Maintenance factor varies by lighting system, environmental conditions and features of luminaires. In this study, calculation of maintenance factors by years and change of lighting levels by different maintenance factors have been analyzed for high-pressure sodium vapour luminaries in tunnel lighting. Accordingly, increasing the maintenance factor used as multiplier in performance calculations will decrease the energy consumed. Therefore, increasing the Maintenance Factor increases the lighting efficiency.

Evaluation method and reduction measures for the flicker effect in road lighting using fixed Low Mounting Height Luminaires

Low Mounting Height Luminaires (LMHL) are used in many cities on viaducts, cross-sea and cross-river bridges due to their unique advantages. However, the flicker effect is an important factor that needs to be considered in road lighting using fixed LMHL. At present, there are not many researchers in the field of international lighting. Previous types of road lighting design were based on the method of the tunnel lighting flicker effect. At the same time, the flicker effect is mainly based on the subjective feelings of people but is not quantified. In this paper, the Flicker Index (FI) is calculated by measuring the parameters of streetlamps to evaluation flicker effect. Secondly, the suggestion to offset the flicker effect in CIE 88-2004 “Guide for the Lighting of Road Tunnels and Underpasses” is to limit the speed of the vehicle and adjust the road light spacing to avoid the flicker sensitive area on human eyes, while ignoring the essential problem of how the flicker effect is generated through the energy level of the stimulating optical signal. Two factors affecting the strength of the flicker effect are proposed: energy ratio and duty cycle. The duty cycle, in time, refers to the proportion of the strong and weak flashing signals during the period; in space, it refers to the proportional relationship between the length of the luminaire and the distance between the lamps, which is related to the running speed of the vehicle. It is consistent with the CIE recommendations for flicker. Thirdly, the essence of the flicker effect is the problem of the energy level of the stimulus signal. This study investigated the reduction in the brightness of the light source, hence reducing the energy of the visual stimulation signal to the human eye in order to judge the degree of fatigue in human vision. The experimental results show that the degree of fatigue in human vision decreases when the brightness of the experimental light source decreases. Therefore, the key to changing the flicker effect of LMHL is to reduce the contrast between the surface brightness of the luminaire and the brightness of the spatial background.

Italian Road Tunnels: Economic and Environmental Effects of an On-Going Project to Reduce Lighting Consumption

Tunnel lighting represents a major cost item for road managers, and particularly in Italy owing to its specific geomorphological and orographic features. In 2018, ANAS, the Italian government-owned road company launched an ambitious program to rehabilitate the lighting systems of more than 700 tunnel tubes across Italy. The Greenlight plan aims to reduce consumption and improve the management of lighting systems while minimizing the impact of works. Outdated high-pressure sodium (HPS) luminaries will be substituted with state-of-the-art light emitting diode (LED) luminaries without modifying the position and the number of the existing luminaires. The project involves an amount of 155 million euros and provides a total return over a less than seven-year period. The first phase of the project involves 147 tubes and is still on-going: 28 GWh (on average 55% of the current consumption) will be saved every year against a 30 million euro investment. More importantly, the economic benefits also have a direct impact on the environment for citizens and safety levels for road users—every year more than 17,000 t of CO2 eq. and 230 TJ from combustion of fossil fuels will be saved. The lighting quality of the artificial lighting inside the tunnel will be enhanced thanks to better uniformity and the color temperature of the luminaries. The experience presented here could be useful since other road managers may pursue a similar approach in order to balance often-conflicting environmental, economic and safety goals.

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

AbstractLighting subsystems account for up to 50% of the energy consumption of a typical tunnel. Day‐time lighting levels account for over two‐thirds of the total system lighting power; their periodic nature creates daily peaks in the tunnel's energy load profile. This paper studies the integration of semitransparent photovoltaic (STPV) cells into sunscreen structures installed above tunnel entrances to reduce tunnel lighting requirements and offset their day‐time lighting loads using energy generated from PVs. The electrical lighting load of a typical 1‐km length road tunnel with and without STPV sunscreen structures was modeled to establish the potential for energy savings. Using a daylighting and energy modeling plug‐in called DIVA, the transparencies and ratios of photovoltaics (PV) to glass of a STPV sunscreen that are in accordance with the luminance reduction code requirements were determined. Reduced lighting requirements over the whole tunnel length, including the threshold, transition, and interior lighting zones of the tunnel were considered, resulting in significant energy savings. The annual power production of the sections covered with STPV was then simulated using the PVsyst software. The integration of PV cells resulted in an annual energy production that reduced annual net‐energy use by up to 7% and with the potential to reduce electric lighting loads by up to 60% during the day‐time. Results also demonstrated that STPV sunscreens have the potential to meet luminance requirements if supplemented with an intelligent lighting control system.

Effects of Luminaire Angle on Illumination Performance in Tunnel Lighting

In this study, the effect of luminaire angle on the path parameters of tunnel lighting was investigated. Tunnel illumination was performed with a simulation program adapted to CIE 88-2004 standards. The lighting performance parameters were compared while the angle of the luminaire was 0°, 5°, 10° and 15°. According to the simulation results, the luminaire angle is 0 degrees and the highest efficiency is reached. As the luminaire angle increased, the yield decreased in direct proportion to the angle. The highest lighting efficiency was observed at 0 degrees and the lowest illumination efficiency was observed at 15 degrees. This problem can be overcome by using a higher power lamp in angled lighting. As a result, it is revealed that angled lighting should be avoided in highway and tunnel lighting.

Analysis of threshold values of contrast revealing coefficient in highway tunnel lighting

Commission internationale de l'éclairage (CIE) defined the contrast revealing coefficient qc based on the perceived contrast method in highway tunnel lighting. Meanwhile, CIE recommended qc as an index in the lighting quality evaluation system. Several studies suggested that qc was 0.6 under counter-beam lighting and 0.2 under symmetric lighting in the threshold zone. However, there were no threshold values of the contrast revealing coefficient qc0 under different lighting systems (qc0 corresponds to the visual adaptation of human eyes). Thus, this study aimed to determine the threshold values of the contrast revealing coefficient qc0 based on small target visibility. The relationship between qc0 and minimum luminance threshold was established in tunnel lighting. Therefore, using the fixed value stimulation approach, the minimum luminance threshold and luminance contrast threshold could be determined under different background luminance and viewing angles. Moreover, based on the luminance contrast threshold, the threshold values of contrast revealing coefficient can be obtained under different lighting environments.

Mechanical deformation mechanism and verification of sections at junctions of light and dark tunnel in a mountain area

Projects involving junctions of light and dark tunnel in mountainous areas are complex engineering problems that combine tunnel structure, slope rock-soil mass and protection projects. Such junctions suffer from a complex and changeable load. The stress and deformation of the junction varies under different conditions. Thus, it is a major source of inconvenience for construction and monitoring operations. In this paper, according to the load conditions at a junction of light and dark tunnel, we divide the junction hole into thrust, compression, and combined thrust-compression types. Three types of structures were simulated by numerical analysis, and we explored the structural deformation and stress of these types of tunnel under different condition. Thus, in any construction process, the mechanical deformation mechanism and the weak point in the structure should be worked out. Based on the weak parts, some monitoring points were installed, and four fields for monitoring were chosen. The monitoring results show that the actual deformation, stress and structural failure location are basically consistent with the numerical simulation results. The deformation mechanism of light and dark tunnel junction obtained can provide the basis for selecting the treatment measures and controlling the structural deformation. Furthermore, the results can also be used as a reference for similar engineering design, construction and site monitoring projects.

Detection of Luminance Level Tolerance in Tunnel Lighting Systems by Maintenance Factor

Bu calismada gun boyunca surekli olarak calisan tunel aydinlatma sistemlerinde bakim faktorunun etkisi simulasyon ortaminda incelenmistir. Bakim faktorunu olusturan temel parametreler anlatilarak bu parametrelerinde kirlilik gibi parametrelerin bakim faktoru hesabina katilmasi gerektigi hesaplamali olarak ortaya konulmustur. Surekli devrede olan-calisan tunel aydinlatmasinda meydana gelen performans kayiplarinin, bakim faktoru carpanini kucultugu anlasilmis olup, standart bakim faktoru yerine detaylandirilmis bakim faktorunun kullanilmasi gerektigi gorulmektedir. Buna gore tunel aydinlatmasinin ilk kurulumu esnasinda hesaplanan %E degerine performans kaybina neden olan diger etkilerde eklenerek bakim faktoru hesabi yapilmalidir. Bu islemler simulasyon ortaminda yapilarak Standart bakim faktoru ve detaylandirilmis bakim faktoru sonuclari karsilastirilarak, ortaya cikan sonuclar degerlendirilmistir.

The Relationship between Maintenance Factor and Lighting Level in Tunnel Lighting

Performance decreases in lighting equipment with a high level of contamination have been analysed in this study. Effect of decreases in luminous flux arising from abrasions and usage on tunnel illumination levels has been analysed and results of measurements in real environment and simulation environment have been compared. Calculations, which are complicated and difficult by traditional methods, have been visualized by a simulation program prepared in the computer environment. Results recorded at 60 points by measuring by a luxmeter, which was placed in the middle of 2.266 m2 fields on the road surface into the tunnel, have been compared with simulation results. Thanks to the simulation program used, tunnel lighting measurements would not be necessary, which they take a long time in the physical environment by measurement devices and are carried out by stopping vehicle traffic. Tunnel lighting maintenances, which are complicated and take a long time, will be carried out in a short time and more accurately, and waste of resources could be prevented. It has been determined in the study that more accurate results could be obtained in ergonomic, economic, and using aspects.

국도터널 조명 및 관리방식 개선을 위한 조사 연구

In 2015, the Land Management Administration measured the road surface illuminance at threshold zone of the national road tunnels and found that 76% of the tunnels failed to meet the standard illuminance. For the request of the Ministry of Land, Infrastructure and Transport, the researchers selected 99 sites out of the 499 national road tunnels and investigated basic information to assess whether the tunnels meet the lighting standard by measuring the road surface luminance of the actual tunnels. Through investigation of lighting conditions and management methods, the problems of tunnels that are not meeting the standard were identified and classified according to the problem types, and improvement measures are proposed. The reflectance distributions of the road surface on the threshold zone and interior zone were measured to analyze the variation of road use, and the adequacy of the maintenance was analyzed through the measurement of the wall reflectance. In addition, the adequacy of the The Luminance to Illuminance Conversion Factor used in the tunnel lighting design was reviewed.

Response of Bioactive Phytochemicals in Vegetables and Fruits to Environmental Factors

This review focused on the influence of environmental systems and/or factors including high tunnel, UV and visible light, fertilization, and irrigation on bioactive compounds in vegetables and fruits. Most studies reported that high tunnel reduced chicoric acid and luteolin in vegetables including lettuce and pac choi, and fruits including raspberry and tomato versus open field, although a few studies demonstrated that high tunnel did not significantly impact on the bioactive compounds. Light including UV such as photosynthetically active radiation (PAR), UV-A, and UV-B, and visible light especially red and blue light, significantly stimulated biosynthesis of anthocyanins, flavonoids, and phenolics, and promoted their contents in vegetables such as onion and spinach, and fruits for example blueberry and strawberry. The effect of fertilization including nitrogen, phosphorus, and potassium on bioactive phytochemicals (carotenoids, flavonoids, polyphenols) in vegetables (broccoli, kale) or fruits (tomato) varied among the cultivars. Water deficit usually increased anthocyanins, flavonoids, and phenolic acids in vegetables such as lettuce and red beet, and fruits including grape and pomegranate. Taken together, the bioactive compounds in vegetables and fruits in response to environmental factors were species- and varieties- dependent. The negative effect of environmental factors on bioactive compounds in vegetables and fruits can be overcome by selecting appropriate cultivars, while the positive effect can be further manipulated in horticultural production for potential consumer’s health benefits.

Research and Implementation of Tunnel Lighting Intelligent Control System Based on ZIGBEE Wireless Technology

Aiming at the complicated wiring and serious energy waste of common tunnel lighting, an intelligent lighting control system is elaborated. Main controller of the system uses a fuzzy algorithm to calculate the required value of brightness. The system adopts ZIGBEE wireless network technology to realize the function of intelligent dimming, switching lamp and automatically detecting and positioning lamp fault. To meet energy-saving and intelligence, the overall design plan from the main controller to the coordinator and then to the wireless node (including router and terminal controller) is expounded. The wireless network technology and the designs of hardware and software for coordinator and wireless node are described, and the communication protocol between the coordinator and the main controller was designed. The actual operation results of the 5 tunnels in Hunan indicate that the system can meet the requirements of tunnel lighting and ensure the safety of traffic. Compared with traditional tunnel lighting, the system can save 55% energy.

Simulation and Design Study for Interior Zone Luminance in Tunnel Lighting

An optimal solution for tunnel lighting designs was determined using a computer software. The road tunnel under construction 14481 m in length was selected in order to get an optimal design solution for tunnel lighting.The lighting, luminaries, and road parameters were changed and the resulting scenarios were examined in a simulation environment. The proposed approach can be applied for the illumination of interior zones in tunnels of 10 km or longer with significant reduction in energy consumption. The optimal luminance values that affect vision comfort in the tunnel were calculated in a simulation environment. As a result, the most economic lighting system and luminaries were chosen among solutions conforming to technical standards for luminance values.

Laser tuned large position-dependent tunneling detection dominated by interface states in silicon based oxide-semiconductor structure.

A laser tuned tunneling detection is observed in SiO2(50nm)/p-Si/SiO2 structure. In comparison of dark condition, the tunneling current get amplified considerably over 250 times when irradiated with a low intensity laser (5mW) directly on the oxide layers. This huge amplified tunneling is unusual and rarely seen. Interestingly, this amplified tunneling effect is of position-dependent, and has a wide adjustment scope (centimeter level). Different from the traditional tunneling effect, where tremendous research efforts were directed only towards the influence of applied voltage or magnetic field, we demonstrate that this laser tuned amplifying process strongly associates with the interface states existing at SiO2/p-Si interface. These interface states can largely collect the light-induced careers and regulate its diffusion in a controllable manner. This work, for the first time, unambiguously demonstrate a novel tunneling detection based on the interface states, suggesting a new approach for light and position sensitive tunneling devices.

Asset Management Model of Tunnel Lighting Facilities Considering a Seismic Risk

現在の社会基盤施設の維持管理において，アセットマネジメントシステムが有効であるが，経年劣化に地震等のイベント・リスクを加味したものはあまり検討されていないのが実態である．過去に著者らが提案した簡易動的マクロモデルは，トンネル照明設備において，トンネル単位系で動的変化する状態確率から劣化予測するものである．本論文では，簡易動的マクロモデルに実際の地震被害率を加味して被害後の健全度予測可能なモデル拡張をした．また，早期復旧時の想定復旧額と想定回復健全度を算出し，コスト有効度の指標を用いてコストマネジメントを行った．これらから，経年劣化にイベント・リスクを加味したトンネル照明設備における新たなアセットマネジメントモデルの有用性を示す．

Modified Savonius wind turbine for harvesting wind energy from trains moving in tunnels

This study is focused on harvesting wind energy from gust produced by trains, that are moving inside tunnels by placing Savonius rotors alongside the trains. Numerical simulation shows that the conventional S shaped Savonius rotor fails to harvest energy under such conditions and hence a new design is proposed to generate useful power without compromising the efficiency of the moving trains. The new turbine design is evaluated to optimize its parameters such as diameter and location with respect to train, considering SMRT's (Singapore Mass Rapid Transit) circle line in Singapore. This unconventional energy production can be a viable energy solution to provide power to electronic components and tunnel lighting.

An energy-saving fuzzy control system for highway tunnel lighting

In order to achieve the goal of energy-saving and safety driving in tunnel, this paper proposes an energy-saving fuzzy control system for highway tunnel lighting. Firstly, a control system for highway tunnel lighting based on IoT technology is constructed. Then, by considering tunnel exterior environmental luminance, traffic volume and vehicle speed as inputs and tunnel interior luminance as output, a fuzzy control model is designed. Based on experts’ experience and “Guidelines for Design of Lighting of Highway Tunnels (China)” (JTG/T D70/2-01-2014), membership functions and fuzzy control rules of different zones are designed. Furthermore, this system has been deployed at the Duan tunnel of Guangxi Province in China and stably operated for more than half a year. The operation results demonstrate that the proposed control method can effectively avoid the “black hole effect” and “white hole effect”, and have a significant energy-saving effect (saving nearly 41% daily energy consumption).

A Global Perspective for Sustainable Highway Tunnel Lighting Regulations: Greater Road Safety with a Lower Environmental Impact.

Tunnel lighting installations function 24 h a day, 365 days a year. These infrastructures have increased exponentially and now connect quite distant locations, even on different continents. This has led European administrations and international regulatory bodies to establish regulations for tunnel safety with the lowest environmental impact. However, until now, these regulations have almost exclusively focused on traffic safety, and relegated sustainability to the background. Even though they recognize the need to reduce energy consumption, they do not propose any tools for doing so. Given the impact of these installations and the lack of a specific regulatory framework, Asian countries will soon be forced either to update previous standards for tunnel lighting or elaborate new ones. A better understanding of the weaknesses of European regulations combined with a willingness to embrace innovation could position Asia as a world leader in the regulation of more sustainable road tunnels. The objective of this research was to improve the sustainability of tunnel lighting installations through new regulations or amendments to existing ones, without impairing the mental well-being of users, who could potentially be affected by energy-saving measures. Accordingly, this paper presents and analyzes a broad proposal for formulating tunnel lighting regulations. The originality of this proposal lies in the fact that it integrates road safety, lower environmental impact, and user well-being. Furthermore, it is expected to broaden the perspective of regulatory bodies and public administrations with regard to tunnel installations, which would ultimately enhance their sustainability.

The effect of segmented lighting on tunnel lighting energy-saving

The aim of this study is improving the effect of tunnel lighting intelligent control system on tunnel lighting energy-saving. Firstly, there are threshold zone, transition zone, interior zone and exit zone in a tunnel basing on the JTG-2014 in China. Then the structure and workings of tunnel lighting intelligent control system are given. The control system uses the method of “vehicle in, light brightens; vehicle out, light darkens” to save energy, and it is worthy for energy-saving. Further, in order to achieve energy-saving more on the basis of the system equipment, segmented lighting is proposed. The working-steps of segmented lighting are listed. The adjustment of LED lamps’ luminance is not synchronous in a tunnel. The LED lamps of threshold zone and transition zone are adjusted to their minimum luminance earlier than interior zone and exit zone for more energy-saving. Finally, the effects of tunnel lighting intelligent control system with and without segmented lighting are compared in energy-saving. Segmented lighting has obvious effect on energy-saving, especially for longer tunnel.

Spin-dependent tunneling of light and heavy holes with electric and magnetic fields

The spin-dependent tunneling of light holes and heavy holes was analysed in a symmetrical heterostructure with externally applied electric and magnetic fields. The effects of the applied bias voltage, magnetic field and reverse bias were discussed for the polarization efficiency of light holes and heavy holes. The current density of spin-up and spin-down light holes increases as the bias voltage increases and reaches the saturation, whereas the current density of spin-up heavy holes is almost negligible. The applied bias voltage and the magnetic field highly influence the energy of resonance polarization, polarization efficiency, and the current density of heavy holes more than for the light holes.