Without energy available any time for our modern necessities of life, the world would not stand still, but it would be unrecognisable. We need it for travel, warmth, light, to prepare meals and drinks, to communicate worldwide, to produce and transport products and services. How much energy that consumes depends on the efficiency of its use.
The supply of energy is not unlimited, it generates costs, and its production has an impact on our environment. As a result, energy efficiency has become a strong competitive factor round the globe, and its significance will further increase in the future. Besides performance, price, quality and design, the carbon footprint – the amount of carbon dioxide (CO2) that is generated during the manufacture and distribution of products – is gaining in importance in the buying decision. Above all, however, energy has become one of the key cost factors in a modern industrial environment. Energy management and decreased energy consumption are, thus, gaining in importance for companies. In order to survive the competition, they must significantly reduce their CO2 emissions. This presupposes increased energy efficiency all along the entire added-value chain.
Bosch Rexroth AG – a worldwide leading supplier for mobile work machines, industrial applications and renewable energies – addresses the topic in two ways. For one, the company has committed to reduce carbon dioxide emissions in all factories worldwide by 20 per cent by 2020. For a very broad product line, the global player utilises a large range of production processes in over 30 production sites: from foundry engineering to cutting technology, from circuit board assembly to installation. Simultaneously, the group develops innovative automation solutions and products that support machine manufacturers and industrial users on the path to increased energy efficiency. Those developments are based on the universal Rexroth 4EE system – Rexroth for Energy Efficiency.
Four levers for energy efficiency. In Germany, over 100 million machines that are not yet consumption-optimised are in use. There are whole series of energy-efficient automation solutions that are suitable to be applied to machines already installed. Retrofittable variable-speed pump drives for hydraulic power units, for instance, control the energy supply in accordance with the demand, creating savings potentials of between 30 and 80 per cent in the field and often even improving productivity. Investments are frequently recouped in the first year of operation thanks to high energy savings.
Only an integrated approach enables machine manufacturers and industrial users to save energy while maintaining productivity without replacing the entire machinery. The energy efficiency specialists at Bosch Rexroth have identified four levers for increased energy efficiency (Rexroth 4EE – for Energy Efficiency) in all machine types: Efficient Components, Energy on Demand, Energy Recovery, and Energy System Design. They help recognise and utilise all significant savings potentials – from design to operation to modernisation. Efficient Components (with optimised energy conversion efficiency) form the basis. Optimised hydraulic pumps, for example, not only considerably reduce fuel consumption but can also lower the emissions of mobile work machines and utility vehicles. In addition, the energy conversion efficiency can be raised significantly. Energy on Demand (energy supply in accordance with demand) reduces unnecessary consumption for all functions through controlled drives.
Examples include situational pressure controls, frequency converters for economical speed control, variable-speed pump drives for reduced idle power, and switching valves for energy shutdown during pauses. Energy Recovery (regeneration of braking energy) keeps energy in the system or feeds it back to the power grid. Servo drive controllers, for instance, achieve that by buffering energy, supplying it to other shafts or feeding it back into the grid. Energy System Design (software solutions and programmes) provides customers with technology-independent application support across the entire production process.
Combining its 4EE system with the energy-saving experience gained in its own plants enables Rexroth to offer a well-founded consulting service. Within the scope of optimising an existing installation, Rexroth energy efficiency advisers analyse the initial situation and identify savings potentials across the entire added-value chain and all machine types. The specialists then extrapolate consumption reduction measures and support them with profitability calculations.
A practical example: at about 300 days of operation per year and a daily operating time of twelve hours, an optimised parcel sorting facility consumes about 23,400 kilowatt hours per year less than before. As a result, the CO2 emissions are reduced by over 14 tonnes per year. In order to achieve that, up to 20 drives were combined into one load circuit. A state-of-the art supply unit returns the braking energy into the supply grid. In doing so, the braking energy is not lost through conversion into heat. Moreover, the electronic control and servo motor being integrated into one compact unit reduces the wiring needs by up to 85 per cent.
Energy efficiency and climate protection are key challenges for the entire machine and plant construction sector. Quick results require an integrated, systematic approach to all of the technologies in the entire added-value chain. Experience shows that it is very well possible to combine climate protection and efficiency. Whether manufacturer or end user – solutions for an increased energy efficiency give innovative companies an obvious head start in the international competition.
Der Autor studierte Physik und promovierte im Bereich Elektrotechnik. Er war mehrere Jahre für die Siemens AG in München und Congleton (England) tätig. Ab 2001 übernahm er leitende Funktionen bei der Bosch Rexroth AG unter anderem als Geschäftsleiter Technik. Seit 2010 ist Dr. Karl Tragl Vorstandsvorsitzender der Bosch Rexroth AG.