Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Clean power from waste heat


Siemens has developed a technology to use waste heat, which previously had gone unused, to generate electricity.

The solution employs silicone oils, which have a lower enthalpy of vaporization than water, and is needed because waste heat produced in industrial plants or power stations often does not have enough energy to drive a turbine with steam. Siemens recently introduced its "Organic Rankine Cycle" module.

Under this solution, the working medium drives a turbine, and then cools and reverts to its initial liquid state. Thus, electricity can be generated without the additional use of energy or raw materials, and without producing additional carbon dioxide emissions.

Conventional power plants usually convert only about 50 percent of fuel energy into electricity, and most of the waste heat is released through a cooling tower. A great deal of waste heat is produced in other industries as well, such as chemicals, glass-making, paper-making and steel production to name just a few examples. It is used often to pre-heat other substances or, if that is not possible and if the waste heat is not hot enough to drive a conventional steam turbine, the valuable energy is wasted.

Using silicone oils, Siemens engineers have succeeded in converting this energy into electricity. These oils have a much lower enthalpy of vaporization than water, and can be used to generate electricity from waste heat of only about 300 degrees. 

The Organic Rankine Cycle (ORC) module is derived from the so-called Rankine Cycle, a closed loop used in steam-driven heat engines. In this case, however, organic silicone oils are used as the work medium.

The oil absorbs the waste heat energy by way of a heat exchanger. It turns to vapor and drives a turbine before being completely liquefied again in a condenser and pumped back to the vaporizer. The heat released in the cooling process is also recovered to pre-heat the oil.

The ORC module has an output of up to two megawatts; variants with higher output ratings are expected to come on line in the medium term. The heart of this module is the proven SST-060 steam turbine, which has already been installed successfully more than 850 times. The silicone oil employed in this module is chlorine-free and non-toxic.

All in all, the investment costs and maintenance costs of an ORC module are comparatively low. And thanks to the lower temperatures and pressures and other factors, it is easier to operate than conventional steam-driven turbines. The ORC module features an automatic mode and requires no additional personnel, making it a very economical option for using energy sources more efficiently

Weitere Informationen:

Dr. Norbert Aschenbrenner | Siemens InnovationNews

Further reports about: ORC Organic chemicals dioxide electricity emissions heat loop pressures silicone steam temperatures

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Climate study finds evidence of global shift in the 1980s

Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.

Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...

Im Focus: Innovative Photovoltaics – from the Lab to the Façade

Fraunhofer ISE Demonstrates New Cell and Module Technologies on its Outer Building Façade

The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...

Im Focus: Lactate for Brain Energy

Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.

In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...

Im Focus: Laser process simulation available as app for first time

In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.

Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...

Im Focus: Quantum Simulation: A Better Understanding of Magnetism

Heidelberg physicists use ultracold atoms to imitate the behaviour of electrons in a solid

Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...

All Focus news of the innovation-report >>>



Event News

Fraunhofer’s Urban Futures Conference: 2 days in the city of the future

25.11.2015 | Event News

Gluten oder nicht Gluten? Überempfindlichkeit auf Weizen kann unterschiedliche Ursachen haben

17.11.2015 | Event News

Art Collection Deutsche Börse zeigt Ausstellung „Traces of Disorder“

21.10.2015 | Event News

Latest News

Siemens to supply 126 megawatts to onshore wind power plants in Scotland

27.11.2015 | Press release

Two decades of training students and experts in tracking infectious disease

27.11.2015 | Life Sciences

Coming to a monitor near you: A defect-free, molecule-thick film

27.11.2015 | Materials Sciences

More VideoLinks >>>