Zurich Accelleron’s core product can’t be overlooked by visitors in the courtyard of the company’s headquarters, not far from Zurich. It is a turbocharger for diesel engines in container ships, taller than a man and the largest offered by the Swiss manufacturer. The company from Baden focuses on the combustion engine. And to elicit more efficient performance from it.
However, Accelleron is relaxed about the approaching end of petrol and diesel engines. Dirk Bergmann, member of the Management Board and Chief Technology Officer, is convinced that combustion engines, especially on ships and in power plants, will not be replaceable for the time being.
In the future, they are likely to be powered by hydrogen, ammonia, methanol or synthetic diesel fuels generated from green electricity. “We will certainly not get a general solution in the foreseeable future, but rather see the entire spectrum,” says Bergmann.
With engines that run on these so-called e-fuels, efficiency is even more important than with conventional combustion engines because production is more expensive than fossil diesel or petrol. Bergmann is therefore convinced: “In the future there will be no combustion engine without a turbocharger.”
Its principle has remained unchanged for more than 100 years: the Swiss engineer Alfred Büchi discovered that the efficiency of combustion engines can be significantly increased by using the energy in the exhaust gases. He found a way to use the exhaust heat to drive a turbine and use it to drive a compressor. The compressor ensured that more air entered the combustion chamber of the engine. In this way, the performance of petrol and diesel engines could be significantly increased while consumption remained the same.
Turbocharger for the fuel cell
Since the 1920s, Brown Boveri and Cie. (BBC) in Baden Turbochargers for large diesel engines. In 1988, BBC merged with Swedish electrical engineering company Asea to form ABB. In 2020, ABB CEO Björn Rosengren decided to spin off the turbocharger business and list it under the Accelleron name. The goal: outside of the large group, the company should be able to concentrate better on its own research and development.
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And so Accelleron is researching, together with the Swiss Federal Institute of Technology (ETH) Zurich, to develop turbochargers for certain fuel cells, the so-called hot fuel cell or solid oxide fuel cell (SOFC). The main difference to the polymer electrolyte fuel cell (PEM), which is already used in cars and trucks and generates climate-neutral drive energy from so-called green hydrogen: the higher operating temperature. The first test results are promising. “That would be a new business area for Accelleron,” says Bergmann.
Christopher Onder, Professor in the Department of Mechanical and Process Engineering at ETH Zurich, also confirms: “The turbocharger is very well suited to increasing the power density of certain fuel cells.”
Great market potential is the opportunity for Accelleron
In fuel cells, hydrogen usually reacts with oxygen – the end product is water. In the SOFC battery, the reaction takes place at temperatures between 600 and 1000 degrees Celsius. This makes them less suitable for use in cars, for example. However, the high-temperature fuel cell has a number of advantages over PEM technology: It does not require expensive precious metals such as platinum or ruthenium. In addition, it can not only be operated with high-purity hydrogen, but also with methanol or ammonia, which can be produced more cheaply from green electricity.
The turbocharger is very well suited to increasing the power density of certain fuel cells. Prof. Christopher Onder, Department of Mechanical and Process Engineering at ETH Zurich
ETH researcher Onder sees possible applications for SOFC fuel cells, for example, in the generation of heat and electricity for houses or settlements. “The hot fuel cell is clearly suitable for decentralized applications,” he says. In combination with heat pumps, for example, they can significantly increase the efficiency of gas heating systems. Use is also conceivable for trucks or trains that travel long distances.
From the point of view of Accelleron board member Bergmann, it could also be used as a power generator on board container ships or cruise ships. And finally, hot fuel cells can play an important role in the production of green hydrogen in so-called power-to-gas power plants, as researchers at Nanyang Technological University in Singapore have demonstrated in a study.
The market potential is therefore large. Important from Accelleron’s point of view: the hot fuel cell has two things in common with a conventional diesel engine: it requires a certain pressure and the reaction produces hot exhaust gas. “This exhaust air contains a lot of energy, which can be used for the turbocharger technology,” says Bergmann. The tests conducted by Accelleron and the ETH show that the efficiency of a fuel cell can be increased by up to ten to 15 percent with a turbocharger.
The technology only works with exhaust gases – but they don’t have to be from the combustion of fossil fuels.
(Photo: accelleron)
Researcher Onder adds: “Instead of letting the heat dissipate to the outside, the turbocharger gets it out again. This energy is free.” Conversely, this means: “With the same output power, the fuel cell with the turbocharger becomes smaller and lighter,” says Onder.
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It may be years before the SOFC fuel cell with turbocharger is used on a large scale. Accelleron and the ETH researchers are currently working on controlling the fuel cell so that it runs constantly at a temperature of 600 to 800 degrees – the temperature window in which the turbocharger works best. In any case, SOFC technology is still several years behind PEM fuel cells, says Bergmann. But he says: “Personally, I believe in fuel cells.”
During this time, Accelleron has made around $780 million in sales and almost $130 million in net profit with its core business, the construction and maintenance of large turbochargers for ships and power plants. ETH researcher Onder says: “The core competence of Accelleron is to extract the last ounce of performance.”
This will continue to be in demand, regardless of whether ships or power plants will be powered by combustion engines with e-fuels or fuel cells in the future. The core problem that electricity from renewable energies is not always available in abundance remains unsolved in the long term.
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