Founded on accurate data – Prizewinning project on energy efficiency in railway vehiclesAward, SNI INSight May 2019
In January 2019, a project by the Department of Physics at the University of Basel, in collaboration with the railway company BLS, received the Watt d’Or energy prize from the Swiss Federal Office of Energy. Initiated by Professor emeritus Peter Oelhafen, the project paves the way for energy savings in railway vehicles. Andreas Tonin from the Electronics Lab of the Department of Physics – which the SNI has supported for many years – played a key part in the project, and Andreas Tonin now finds himself at the heart of a follow-up project in collaboration with the operators of the Lausanne metro system.
Exploring potential for savings
Public transport is another area in which energy can be saved, but it is important to determine which subsystems are worth modernizing before measures are implemented. Professor emeritus Peter Oelhafen, from the Department of Physics at the University of Basel, proposed doing precisely that. In a collaboration with the railway company BLS, sensors were fitted to a “NINA” low-floor suburban railway train in 2011. Since then, the sensors have been recording the exact energy consumption of a range of devices and systems, as well as climate data, and storing these readings on a data server.
Targeted modernization saves energy
It turned out that about a third of the energy was needed for heating, ventilation and cooling, and that the trains used approximately another third while stationary, because many of their systems were not switched off. The precise measurements paved the way for targeted innovations that helped reduce the overall energy consumption by around 20%. These measures included the introduction of a standby mode and needs-based regulation of the fresh air supply. Moreover, the trains have been fitted with modern lighting technology and nanocoated windows that offer improved thermal insulation but that are nevertheless transparent to mobile phone signals.
The project was a complete success for everyone involved and was ultimately awarded the Watt d’Or by the Swiss Federal Office of Energy in January 2019.
Follow-up projects launched
Further transport companies are now involved in projects aimed at recording consumption and climate data in passenger trains in collaboration with the University of Basel and other Swiss research institutions (Lucerne University of Applied Sciences and Arts, Empa, EPFL, Bern University of Applied Sciences, University of Applied Sciences and Arts of Southern Switzerland). These initiatives are supported by Swiss electric research and the Swiss Federal Offices of Energy and Transport.
For example, another collaboration with Lausanne’s transport operators (tl) has been underway since November 2018. This involves taking measurements on a metro and follows on from a trolley-bus study that has been running in the city since 2015. Having made a key contribution to the prizewinning project with BLS, Andreas Tonin from the Department of Physics in Basel also plays a central role in this collaboration. In April 2019, measurements have begun: “In Lausanne too, we’re continuously measuring the energy consumption of various subsystems, as well as recording climate data.”
Numerous coordinated components
Although this sounds simple at first, it is actually quite a complex undertaking. The temperature, humidity and CO2 level are detected at various locations in the passenger compartment as well as in the two driver’s cabs of this two-car commuter train. Solar irradiation is also measured, as are the outdoor temperature and the opening times of the doors. As the metro mostly travels above ground, it is possible to determine its precise location using GPS, and sensors also measure the energy consumption of the engines, heating, lighting, information systems and cooling system, which is only present in the driver’s cabs. The energy recovered during braking is also recorded. In the metro, it is essential to find suitable locations to install all the equipment, and the measuring system must not hinder the train’s operation in any way. All the measuring instruments are therefore electrically insulated from the vehicle system and supplied exclusively from the vehicle battery, which is protected against excessive discharge.
Since November 2018, Andreas Tonin has been planning, building and documenting the system and preparing the installation of the various sensors and measurement systems, which he must adapt to local circumstances. “Since Lausanne’s metro system runs mainly on direct current (750V, 24V), the measurements are significantly more difficult than in the NINA project,” he says. Each of the current and voltage values must be measured separately and multiplied together to determine the power. This is done around 30 times a second. Using a special system, the individual power values are used to calculate the total amount of energy used on an ongoing basis. Consumption meters, such as those found in the home, are designed for alternating current and are therefore only used for the air-conditioning units, which are powered by an inverter.
Started in April
As planned, mobile technology is used since April to automatically send all the readings to a data server on a daily basis. Data can then be retrieved from the server.
Andreas Tonin acts as the data manager. He delivers data to the other project partners and analyzes some of the data himself. Everyone involved is excited to see what conclusions can be drawn from this wealth of data and which of the findings can then be implemented in the form of energy-saving measures, as with the NINA trains operated by BLS.
More information about the prizewinning project:
Watt d’Or 2019: Step by step to greater energy efficiency: