The energy-saving roasting plant

Tchibo experts at our facilities in Wendenstrasse, Hamburg, are constantly seeking new ways of making the refining of raw coffee even more energy-efficient.

You don’t have to be a very imaginative person to see why employees have given this steel structure the nickname “nesting box”. The object, which has something of a bay window shape about it, is attached to the outer wall of the workshop without touching the ground. Of course there aren’t any birds building their nest here – the construction would be big enough to house four lorries. However, nature lovers may also take an interest in this box’s “resident”: after all, it’s helping to improve the roasting plant’s environmental footprint. Its name: RFB4.

This unprepossessing abbreviation stands for Tchibo’s most up-to-the-minute roasting system, located in Wendenstrasse in Hamburg, Germany. Introduced in 2010, the newcomer is expected to outperform the other roasters by far. “RFB4 basically has two tasks,” explains Helmut Plath, occupational safety and environmental protection officer for Tchibo’s roasting plants. “First, we of course want to optimise our coffee roasting process. Second, we want to minimise energy consumption during roasting.”

The 53-year-old environmental protection officer has been working for Tchibo for almost a quarter of a century. Continuously sharing information and views with experts from the field of science and research as well as Tchibo’s environmental technology specialists, Helmut Plath and his colleagues are contributing to constantly improving the environmental footprint of the organisation’s roasting plants. Energy efficiency is a key aspect and has been continuously improved since the 1980s, leveraging both environmental and business benefits.

Helmut Plath in front of the RFB4 roaster’s auxiliary burner, which ensures that the roasting machine’s catalytic converter reaches its operating temperature.

Optimisation potential has been fully exploited

The current state of affairs is that the plant has already tapped into all obvious energy-saving possibilities. Efficient fluidised bed roasting has been established for years; using the energetic benefits of recirculating hot air in closed circuits is another proven strategy. A dedicated team works on harmonising the needs and requirements of production, warehousing and sales units, ensuring that energy consumption is reduced to the minimum. In short: All significant potential for optimisation has been fully exploited. “We are unlikely to make any great leaps now,” says Helmut Plath. “We now have to fine-tune processes and equipment to further reduce the energy and heat consumption of our machines.”

Targeting the 350-degree mark

The RFB4 is proof that it is possible to achieve such improvements. As with all other Tchibo roasters, a catalytic converter ensures that the intense aromas released during the coffee roasting process are not emitted to the environment. But the catalytic converter requires energy to operate, heat energy, to be more precise, which is generated by a gas burner. Years ago, the catalytic converter had a combustion temperature of 550 degrees. Many minor improvements helped to reduce this temperature without impacting the catalytic converter’s performance. Low temperature catalytic converters, as installed in Tchibo roasting plants, operate at 400 degrees. And even this value is to be further reduced. Tchibo technicians and engineers at Wendenstrasse are targeting the 350-degree mark. “Compared to current installations, such an ultra low temperature catalytic converter would save another 12 percent in heating gas for operating the catalytic converter,” said Helmut Plath.

Terrance Cain, production controller, monitors the roasting process from the control room – the “command centre” of the roasting plant.

Each roaster has a screen which displays the exact status of the roasting process for each individual batch. The picture shows the screen of a RFB roaster running in test mode with an ultra low temperature catalytic converter.

Sealing to save energy

The complex structure of a coffee roasting plant offers a range of opportunities to cut energy consumption. Employees jokingly call Marc Reckhemke and his colleagues on the in-house mechanics team “the sealing crew”. The nickname refers to the technicians’ constant drive to optimise sealing of tubes and systems to the outside, thus avoiding loss of energy.

And the skilled “sealing crew” is not only good at working with insulating materials. The mechanics pride themselves, for example, on having further minimised flow resistance in the roasting plants’ pipework in cooperation with roasting plant designers. The idea is quite simple: The lower the flow resistance is, the less power the fans require to force air through the pipework.

Piling on the pressure – with fine tuning

The mechanics are also making progress in another field: As in many other factories, huge parts of the Tchibo plant operate on the basis of compressed air. Roasting plants or packing machines would not run without pneumatic force. But compressors are required for generating compressed air – and these use electric energy. In 2010, the power consumption of compressors was reduced by ten percent at the Tchibo roasting plant, equalling 132,000 kWh per year, due to the installation of frequency-controlled compressors. Unlike previous models, these compressors are continuously variable, allowing them to be adjusted to demand at any time.

Marc Reckhemke in the operation of the of frequency-controlled compressors.

For an even more efficient future

Frequency-controlled compressors, low-consumption catalytic converters and sophisticated roasters – in view of this wealth of cutting-edge tools and systems you might think it impossible to make a roasting plant still more energy-efficient. However, Helmut Plath will prove you wrong: “We are currently preparing an energy management system for our facilities. It will serve to identify any further energy-saving potential.”