“There’s no single concept that works for everything and everyone”

An interview with Professor Dr.-Ing. Dieter Brüggemann

Professor Brüggemann, your specialty is thermal energy technology. The transfer center you have been heading up for 18 years also works in this field. What were the specialist topics of the times two decades ago, and what are the challenges that occupy you now compared to then?

Even in those days, energy was an important issue. For example, people were interested in making combustion as efficient as possible and reducing pollutants. We worked successfully with laser-optical measurement technology and simulation techniques, and we’re actually still using these today. But our activities are much broader now. You just need to think about the extensive climate debate. A big issue these days is sustainability and avoiding carbon emissions. The goal posts have shifted. Renewable energy sources were something really special back then. Today they dictate the discussion and sometimes lead to new challenges.

Among other things, your Steinbeis transfer center tests combustion chambers in gasoline engines and diesel engines. In your opinion, given the current debate about environmental protection, what should we be thinking about environmental compatibility? Do recent technological advances make retrofitting an environmentally friendly and affordable option?

It’s important to consider how much has already been achieved. Thanks to research and development work, modern combustion engines now only generate a fraction of the pollutants their predecessors did under comparable conditions. That said, at the same time, our expectations regarding vehicle safety, comfort, performance and zero emissions have gone so far that we need to keep researching and developing.

A certain amount of the energy we now produce goes unused because it’s not needed where it was generated. This is a problem that goes back to the energy technology. If we set up pipeline systems to shift it around, it soon becomes expensive. Your Steinbeis transfer center works in this area by looking at mobile latent heat storage and transportation on trucks. Give us some insights into this future technology solution!

Before I do: There’s no single concept that works for everything and everyone. This is precisely why the individual advice we give to companies and institutions is so important – customized, made-tomeasure solutions. Sometimes the challenge is to take excess heat and load it onto special storage devices and to then transport this to the place it’s needed, where the heat is then offloaded. The advantage you get with latent storage is that energy doesn’t go into the heating of the material but into melting it at an almost constant temperature. Basically, these storage systems work like those hand warmers people use in winter – only on a much larger scale. And it’s the size that’s one of the challenges: how can I load and unload the heat as quickly and uniformly as possible? In other stationary applications, the priority is to keep the temperature of a component or room constant. We regulate this by selecting the right materials. This is an area we’ve also been doing R&D work in with LTTT at the University of Bayreuth. And yet another big topic for us is how to transform heat into electricity using the organic rankine cycle (ORC). It’s a really useful technique when the temperature of a heat source (e.g., geothermal heat or waste heat) is too low for a conventional water-steam power plant.

Daily newspapers have been full of buzzwords for some time now – terms like solar energy, wind power or the transition to renewable energy. There are discussions and disagreements, but everyone seems to agree that our energy supplies should be environmentally friendly, safe and affordable. Is this ideal actually possible?

In the long term, certainly. In the short term, only partly. But this shouldn’t be a surprise to us. If we turn the whole energy supply concept on its head overnight by decommissioning nuclear power stations and only burning coal when absolutely necessary, or gas for as long as necessary, this has implications for our electricity supplies. Wind and solar energy will also have peaks and troughs, but in the energy mix, it has the right of way. So the old concept of normal, high and peak consumption will have to be replaced by new concepts. To do that, you need time, money and determination, but also a willingness to make compromises. We sometimes make decisions without wanting to know about the consequences, without considering the “if – then.” For example, if someone’s set on using offshore wind, they’re going to have to accept that there will be lots of electricity pylons everywhere.

Let’s take a sneak peek at the future. What, in your opinion, will the energy market look like in 2050? What will be the future priorities in energy research?

Well I’m not a clairvoyant, but the way I see it, there are three factors which have a particular impact on developments: technology, politics and, last but not least, people. Who would have predicted three decades ago that a small and affordable item called a smartphone would come along and more or less replace not just conventional telephones but also computers, books, maps, notebooks, watches, alarm clocks, calculators, cameras, CD players, video machines and quite a few other things. This is a perfect example of the interplay between technological innovations and user behavior. For users, the freedom to use things wherever they want, whenever they want is more important than the size of images or sound quality. In a similar way, when it comes to the future energy market, it will depend on whether people radically change their behavior. Initial trends are beginning to emerge. We are now seeing younger people place much less value on the size or engine power of a car, or actually even owning one in the first place. Another issue is whether we want to reveal our private behavior just to optimize the energy use of our household devices, the heating or the lights. Then apart from the people and the technology, political developments are important. Would we prefer to answer energy requirements on an international scale and compensate for fluctuations on a European level? Or will the trend go more in the direction of decentralized power generation in our own four walls, locally, or within the region?

I’m pretty certain, at least in the next few years, that we’ll need a mixture of energy sources. That’s also why it makes sense to not put our money on one horse. So I’m confident that our expertise in the field of energy systems planning and thermal energy technology will still be needed and we’ll continue to make some useful contributions.


Professor Dr.-Ing. Dieter Bruggemann is director of the Steinbeis Transfer Center for Applied Thermodynamics, Power and Combustion (ATEV) at Bayreuth University. The center’s key areas of work include power engineering, thermodynamics and heat transfer, combustion research, optical measurement technology, laser diagnostics and numerical simulations.

Professor Dr.-Ing. Dieter Brüggemann
Steinbeis Transfer Center Applied Thermodynamics, Power and Combustion (ATEV) (Bayreuth)
SU0311@stw.de | www.steinbeis.de/su/0311

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