Drivers of Sustainability
The approximately 250 members of the Electronics, Energy & Environment (EEE) Cluster carry out research into a broad range of topics.
The EEE Cluster’s eight Global Technology Fields (GTFs) conduct research for all Siemens sectors. For the Energy Sector, for example, the cluster focuses on the entire energy conversion chain, where new technologies from CT are helping to make the generation, transmission, and consumption of electrical energy more efficient, and thus also reduce CO2 emissions. For the Industry Sector, researchers focus mainly on new drive concepts and technologies for improving energy efficiency. Research on biosensors, on the other hand, is opening up new in vivo and in vitro diagnostic possibilities for the Healthcare Sector, where highly-effective electronics are enhancing Siemens’ leadership in medical imaging.
Power grids must be optimized in order to increase energy efficiency. Peak loads have to be reduced and capacity utilization in general has to be made more uniform. Power plants should operate as little as possible at inefficient partial or zero loads, but should also be able to react quickly to increasing demand. Energy utilities want to use smart grids to optimally balance supply and demand and also integrate fluctuating sources of renewable energy such as wind and solar power into the electricity grids.
To make all this possible, companies need efficient processes for intermediate energy storage. Experts from the Energy Conversion & Environment GTF are examining several energy storage options, including the use of hydrogen. Hydrogen is produced by means of high-pressure electrolysis, using excess electricity generated from renewable sources. The gas is subsequently stored in pressure tanks so that it can be used in gas turbines for power generation or as a vehicle fuel when demand increases.
However, excess energy can also be used directly where it is needed – to provide heating or warm water, for example. In March 2010, the Power Components & Thermodynamic Processes GTF put a testing platform into operation in Erlangen, Germany, to investigate such applications. For example, having generated electricity from photovoltaic or solar-thermal systems, researchers analyze how this electricity can best be converted into different forms of energy – such as heat or cold – and stored.
Excess wind turbine power drives electrolysis systems that produce hydrogen.
Lasers boost gas turbine efficiency
Fossil fuels will continue to be used in power plants to cover rising demand for energy, making it essential that the efficiency and energy yield of such plants be further improved. To this end, scientists at CT are primarily focusing on the operating temperatures of gas turbines, which had previously seldom been precisely measured and instead were generally estimated on the basis of experiential values. Because turbines have to be protected against overheating, they are currently operated at only about 85 percent of their rated load as a safety precaution.
Researchers at the Sensor Systems & Applications GTF have developed an optical sensor that can determine the temperature profile of a gas turbine’s exhaust gases in real time. To make such measurements, an optical grating is inscribed into an optical fiber, creating a socalled Bragg sensor that is then hit by a laser beam. The reflected beam creates an interference pattern that varies according to the lattice constant, the fiber’s refractive index, and other factors. The lattice constant and the refractive index change when temperatures fluctuate, making it possible to determine the temperature at any given point in time. Because the fiber is very thin, it can also be used in hard-to-reach locations. The new principle has already been tested in a gas turbine in Finland.
Turbine insight: CT-researchers have developed a sensor that can measure temperatures of gas turbines.
Champion energy savers for all areas
In addition to production, energy consumption has to be made more sustainable as well. This means, for example, optimizing drives to produce the maximum output while minimizing energy consumption. An example of such a “champion energy saver” is a ship propulsion system that was developed by the Power Components & Thermodynamic Processes GTF and the Industry Sector’s Marine Solutions and Large Drives units and will be used for the first time in 2012. Thanks to the use of high-temperature superconductors, the rotor in this propulsion system incurs no electrical losses, which increases its efficiency compared to conventional electrical drives. At the same time, the rotor coils’ superconductors have a current density that is 100 times greater than that of copper coils. This makes it possible to reduce their weight and volume by up to 50 percent, which reduces the costs, energy requirements, and quantity of raw materials used.
Motors for industrial facilities also have to be extremely efficient and at the same time be as compact and quiet as possible and have long maintenance intervals. However, the smaller a motor is, the higher the risk it will overheat. Small drives simply have no room for conventional air cooling systems. To solve this problem, scientists at the Power Components & Thermodynamic Processes GTF have developed a completely new cooling method that uses a thermosyphon to transport energy from the hotter to the cooler end of a closed-loop system. The system contains a liquid, which in the simplest setups consists of water. The liquid vaporizes at the hot end, creating steam that flows back to the cool end where it condenses. Because of the arrangement of the cooling system, the condensate then flows back to the vaporizer. What’s special about such a cooling system is that it requires neither pumps nor valves; this makes it much more effective than air cooling or even conventional water cooling. Thermosyphon cooling can even be incorporated into existing drives, as was demonstrated in a test of a 10 kW standard drive system. The test showed that the system substantially reduced the load on axle bearings, which has a positive effect on service life and improves efficiency by two percent.
In the Healthcare Sector, researchers from the Actuator & Drive Systems GTF have developed an innovative multi-leaf collimator for Xray machines and radiation treatment that makes it possible to create two-dimensional profiles. The system uses tungsten discs to filter out X-rays. A group of actuators moves hundreds of tungsten discs to generate high-precision 2D images. In this way the system can precisely define the radiation profile used in oncology, thus significantly reducing patients’ exposure to radiation.
| Elimination pollutants in water |
| Another research focus of the EEE Cluster is environmentally compatible water treatment methods. Researchers have developed an electrochemical process that allows pollutants to be removed from industrial and municipal wastewater in an environmentally friendly manner. The system channels wastewater through a cell while applying an electrical charge. This causes the pollutants’ molecule chains to break open and transform into free radicals. At the same time, the cell’s electrolytic function splits the water into hydrogen and oxygen. The free radicals are eliminated by oxidizing with the oxygen. Because this process requires no chemicals, it does not produce any contaminatedsludge, which has to be expensively and laboriously disposed of in other water treatment systems. Pilot tests of this oxidation process with wastewater from cellulose production have demonstrated the cell’s high performance under real-life conditions at a paper factory. Researchers have also developed a method that uses pulsed discharges to create highly active radicals that eliminate substances such as medication residues that are especially difficult to remove from wastewater. Some of these persistent substances, including PFT and medications such as Iopremol and Diclofenac, cannot be eliminated using conventional methods. The electrochemical cells could even be used in private households to disinfect water in dishwashers, for example. Ozone generators are currently the only systems offered for this purpose. An electrochemical cell would be much more robust as well as being easier to integrate into a dishwasher. |