The dark winter months are fast approaching – and poor visibility with them. Bright light and good illumination are a must, especially in waiting shelters, on busy roads or directly on the tram tracks. Accidents due to a lack of light are the order of the day. That must not and should not be. With modern and efficient LED lighting, we want to ensure more safety on the road.
This is especially a current topic in the municipality of Reichshof. Here, there are around 200 bus stops, many of them in the open countryside. No street lights, no power connection. This means poor visibility and danger, especially in the dark season. Students from the Gummersbach campus of the Cologne Technical University have taken on this problem and recently presented their project work “Autarkic solar lighting unit” in Reichshof-Mittelagger, where the pilot unit is putting the bus waiting shelter in the right light.
The laboratory for analog and optoelectronics of the Technical University of Cologne, Gummersbach campus, has been cooperating successfully for many years with WSM in Waldbröl, which manufactures waiting shelters, residential containers, showcases and many other products. Thus, LED-illuminated showcases have been developed together. This cooperation has now also been extended to the field of illumination of waiting areas or, more generally, of shelter systems
The completely self-sufficient solar street light was designed installed and metrologically checked by the Technical University. As already mentioned, unlighted bus stops represent an increased risk of danger. A serious traffic accident with a schoolchild occurred in the municipality of Reichshof several years ago. Due to this event, the idea of (self-sufficient) illumination of bus stops independent of the public power grid was born. The preliminary work for this project began in 2014 with a photometric survey of bus stops in Reichshof. Everything was installed and completed in 2015. The illuminated bus stop that we designed is in Reichshof-Mittelagger, Eckenhagener Straße 4, in 51580 Reichshof.
Task definition and concept
The project was implemented by students as part of the “Optoelectronics” elective course under the guidance of Professor Dr. med. Bärwolff. Initially, the main task was to find suitable components for the project of self-sufficient, solar street lighting through research, simulations and calculations. Subsequently, the selected components were ordered.
For the construction of the system in 2015, two solar modules at approx. 300 W were first mounted on the roof of the barn and secured there with an additional holder for solar modules. In the barn, a timer, a switch cabinet socket and the calcium-silver battery (120 Ah) were installed in the charge controller switch cabinet by the students. In addition, additional backups were installed. Furthermore, a twilight switch was attached to the outside of the barn. The bus stop itself and the surrounding area are well lit with 2 LED lights of 900 lumens each. The timetables are programmed with the timer so that 5 min. before the arrival of the bus the light turns on and later automatically turns off again. Here, a motion sensor is to be additionally installed. In mid-November 2015, a first test run of the unit under the supervision of Professor Dr. med. Bärwolff was conducted. Shortly after the first test runs, the system was officially inaugurated by the village association and the mayor of the municipality Mr. Gennies and has been operating self-sufficiently since the end of November 2015. The following photo shows the bus stop with the managing director of WSM Mr. Schenk, further colleagues and Prof. Dr. med. Bärwolff.
Image added by WSM
Finally, with the help of a data logger provided by the TU Cologne Gummersbach campus, data from the system was logged in order to be able to make a statement about whether the system is functioning perfectly.
The recorded data show that the system is sufficiently dimensioned even for the dark months of the year and has been working without interruption. This innovative and future-oriented project has shown that, with limited effort, it is possible to supply energy from solar modules to bus stops without a nearby power grid and to illuminate them with LEDs. LEDs were the logical choice for lighting because they consume less power, last longer, and are far more powerful than traditional bulbs or tubes. Furthermore, it was very interesting, because the project actually initiated impetus in the Mittelagger district of the Reichshof municipality, the residents were very interested and in the morning now students find an illuminated bus stop and thus more safety on their way to school.
The system can be expanded or reduced as desired. It can also be constructed with mast support. It must, of course, be adapted to the prevailing environmental conditions at the installation site. If, for example, the average solar radiation at the location is very low, the solar modules must be highly efficient and, if necessary, the number of modules themselves increased. If a LED with 10 watts is sufficient, depending on the solar inclination, the number of modules can be reduced and still a sufficient solar yield can be generated. There are also bus stops where shade from trees or shrubs is so widespread that a solar solution does not make sense. The whole system must be carefully calculated and designed depending on the location.
Considerations and suggestions from the village association included the idea of installing a motion sensor which, in conjunction with the twilight sensor and the programmed timetables, controls the LEDs. The positioning of such a motion sensor should be done below the mounting fixture of the LEDs or inside the bus stop, in order to minimise triggering by passing motor vehicles and to maximise the probability of triggering initiated by movements of people waiting at or in the bus stop.
Meanwhile, other communities have expressed interest in solar lighting concepts for stops and shelters. As already mentioned, interesting cooperation can be initiated here between the Gummersbach campus of the Cologne Technical University and WSM. The involvement of a professional company with a focus on LED and lighting is planned. Talks have already taken place between the “Wir sind heller ” (WSH – “We are brighter”) company from Bergneustadt, the TU and WSM.