Heat leaks and power guzzlers – Making energy efficiency a shop-floor reality

In Hanover, the first specific solutions for the energy-efficient production operations of tomorrow will be unveiled, not least by Bosch Rexroth. The company is working closely together with the researchers at Darmstadt University.

Professor Eberhard Abele, Director of the Institute for Production Management, Technology and Machine Tools at Darmstadt, saw his heart’s desire granted in 2000. After 15 years in the industrial sector, the cybernetics graduate, with a doctorate in mechanical engineering, wanted to build a factory at the university, to educate students under realistic conditions. Abele has seen his wish come true twice: in 2007, he founded the Process Learning Factory (CiP) in Darmstadt; and in 2016 the Energy-Efficiency, Technology and Application Centre (ETA factory).

Training and researching energy-efficiency

Abele’s motivation was self-evident to him: while CiP serves as a competence centre for Lean production and Industry 4.0, the ETA factory was tasked with training and research in the field of energy-efficiency. It is required, for instance, to serve as a learning factory, with whose aid Darmstadt University also aims to integrate the topic of energy efficiency into the curricula for mechanical and construction engineers.

To quote Professor Abele: “Today, all first-semester mechanical engineering students are already being confronted with the potential for energy savings in production operations. In subsequent semesters, they then find an almost ideal environment for trying out their own creative approaches to improved energy-efficiency in dissertations and theses.”

The ETA factory, however, is primarily a large-scale research laboratory for industrial energy efficiency, helping the German government to halve energy consumption by 2050 in comparison to 2008. In this context, the industrial sector plays a crucial role, since according to the German Federal Environmental Agency it consumes nearly one-third of Germany’s total energy usage. Reason enough for the nation’s Federal Ministry of Economic Affairs and Energy to subsidise the ETA factory’s construction, its entire equipment and its long years of research work with €15m.

Improving the interaction of all components

The ETA factory is tasked with holistically improving the co-ordinated interaction of all a factory’s components and systems – from machine tools to the building’s technical equipment and envelope – so as to downsize its overall energy consumption. On the same area as a typical indoor handball court (around 800sqm), there is not only a learning area for students and employees from the industrial sector, but also a machinery zone with machine tools and cleaning machines plus a hardening furnace – in which control disks for hydraulic axial piston pumps are produced. The ETA factory covers all stages of industrial manufacture, from the blank to the finished part.

The production of pump components, however, is only a means to an end, since it’s here that new concepts for energy savings are being developed under real-life conditions.

“The former state-of-the-art has been that individual components are scrutinised separately,” says Abele. “In conjunction with machinery manufacturers, construction engineers and architects, we are aiming to analyse and optimise on a cross-disciplinary basis machine components, production machines, the process chain, a building’s technical equipment and its envelope from the viewpoint of energy-efficiency.”

Besides design-enhancing production processes, other focuses include the co-ordinated interaction between technical equipment and machinery. The technical leitmotif here is multiple networking of the factory’s individual modules: a heat network links the machines together and to the building’s envelope using heat pipes. The façade incorporates an integrated array of very small tubes, enabling it to react to the temperatures outside, and respond accordingly, either by cooling or heating the water in the pipes. It is supported in heating the factory hall through the heat networks by the waste heat from the machines, though this is also utilised by other systems, like the hardening furnace.

“Customarily, the water used for cooling the machine’s drive elements is continuously cooled down again,” says Abele. “This is simply a total waste of energy. We now no longer cool down the entire water supply, we even heat it up a bit to 80 degrees Celsius – for the downstream system that cleans the metal parts, to cite one example.”

For cooling the drive elements, the machines instead use cold water from the mains.

The ETA factory also possesses a data network that links together all the areas involved.

“We combine the control of energy consumption with Industry 4.0,” emphasises Professor Abele. “In this way, the acquired and edited data can be used for optimising the energy consumption.”

International interest

The ETA factory is an international role model, but it’s not only in Germany that the idea of downsizing energy consumption with the aid of a research factory is arousing keen interest. For instance, business engineer Martin Beck, Group Leader for Eco-Compatible Production at the ETA factory, is advising a company that’s setting up an energy-efficient machine factory in Singapore. But he has encouraging words for small and mid-tier companies too, urging them to take advice from the ETA factory or from other existing energy-efficient factories.

“It pays off for mid-tier enterprises, in particular, who won’t usually possess an energy efficiency department of their own,” says Beck. “The energy costs account for around 3% to 5% of the total costs, of which we can save 10% to as much as 40% using rigorously targeted, holistic, often state-subsidised consultancy.”

The expenditure on what are called energy-intensive industries in Germany are particularly high: every year, they reportedly spend more than 5% of their turnover (around €17bon) on energy.

In addition, the ETA factory (according to an Institute for Production Management, Technology and Machine Tools (PTW) newsletter) serves as a “large-scale research device” for ambitious projects. These include the Copernicus project entitled “SynErgie – Synchronised and energy-adaptive production technology for flexible matching of industrial processes to a fluctuating energy supply” currently being subsided by the government with €30m. There are about 100 partners involved in this project, from the industrial sector, the research community and society as a whole.

Abele, who is also President of the German Academic Society for Production Engineering (WGP) defines the goal as follows: “We are networking wind turbines and solar modules with the production machine.”

Alternative energies like wind and solar power mostly produce either too little or too much energy.

“We want to render the production facilities so flexible that they can themselves react to this fluctuating supply of energy,” says PTW Senior Engineer Stefan Seifermann.

This is an important undertaking, since renewable energies in Germany were already accounting for 31% of the gross power consumption in 2015.

SynErgie is initially beginning with seven energy-intensive sectors, one of which is machinery and plant construction. The connected load of the individual pieces of equipment concerned is in this sector significantly lower, but conversely very many more machines and lines are used than in other branches of industry. There is keen interest from this sector, as a glance at the participants shows: under the leadership of Professor Matthias Putz from the Fraunhofer IWU in Chemnitz, firms like Bosch, Festo, Handtmann, Hirschvogel Automotive, Siemens and Volkswagen Saxony are working together on this project.

The means to this end are highly dynamic control platforms that take due account of the fluctuating energy supply, and regulate accordingly the energy distribution between industrial processes like cleaning, hardening or metalworking. To quote Abele: “Only when companies know when a lot or very little power is being generated from renewable energies, and the stock market is signalling this by low electricity prices, can they react appropriately.”

Distributed intelligence and open interfaces

Bosch Rexroth is participating in the SynErgie research project in order to develop open- and closed-loop control strategies designed to match the energy consumption to the fluctuating supply. For this purpose, the research project is prioritising distributed intelligence in the actuators and cross-manufacturer interfaces capable of also supporting Industry 4.0 applications.

Decentralised, intelligent control systems and drives from Bosch Rexroth will, according to the company, be capable in future of scheduling breaks to match the supply situation, and without any superfluous waiting time restoring readiness for production at the right juncture. This necessitates intelligent shutdown and ramp-up capabilities for the lines concerned. Rexroth will in future be equipping the drives, drive controllers and control systems with the appropriate software functions and cross-manufacturer interfaces. These interfaces support the requirements of Industry 4.0 concepts, and supplement them with a dimension of energy-efficiency.

Bosch Rexroth is also involved as a co-initiator of the ETA factory. Here, for example, under real-life conditions, researchers are addressing the process chain of a hydraulic component from the Rexroth plant in Elchingen, and communicating how energy can be utilised even more efficiently by using a new holistic approach and intelligent networking of the building envelope, the technical building equipment, the energy storage units and the production lines themselves.

Anyone interested can find out more details at the EMO Hannover 2017, where Bosch Rexroth will be addressing not only the topics of networked hydraulics and Industry 4.0, but energy-efficiency as well.

“Rexroth’s systematised 4EE concept (for Energy Efficiency) taps into cross-technology savings potentials in metal-cutting and forming production operations,” explains Hansjörg Sannwald, Head of Sectoral Management Machine Tools.

For example, variable-speed pump drives for hydraulic systems consume up to 80% less power than their constant-speed counterparts. But where do we go from here in terms of energy-efficiency? The expert is confident that networking based on Industry 4.0 will make it possible to couple all consumers in a production line or factory for optimised energy management.

“The software will know in advance the machines’ upcoming consumption values, and will be able to shift load peaks against each other,” he says. “This, however, is absolutely conditional upon open communication standards and decentralised intelligence.”

EMO Hannover 2017 – the world’s premier trade fair for the metalworking sector – will be held from 18 to 23 September at Hannover Exhibition Grounds in Hannover, Germany.

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