Heidelberg Designs Green Printing Presses

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There is no getting around it: printing presses use up a lot of energy, and large presses even more. A six-color Heidelberg Speedmaster XL105 with coating unit consumes–without technical enhancements–up to 560,000 kilowatt-hours of power to produce 36 million printed and coated sheets over the course of a year. But Heidelberg is working harder than any other company serving the industry to systematically reduce the energy consumption of every individual component of its sheetfed offset presses.

"Considering all of the improvements for saving energy, the power consumption of a Speedmaster XL105 can be cut by about 20%, or 120,000 kWh per year." - Heidelberg

Dryers, cooling systems, drive motors, air compressors there are many opportunities to reduce the energy consumption of a printing press. Heidelberg takes advantage of them with an integrated approach to the design of the printing press.

Take dryers: They account for 35 percent of the total, making them the single largest power drain. Drying is done with infrared radiation and hot air. Reducing the distance between the paper and the dryer drives moisture faster and better out of the printed sheets. Heidelberg has succeeded in placing the dryer two centimeters closer to the sheet. Each centimeter saves about five percent of the energy consumed. Altogether, Heidelberg has reduced the distance between the dryer and the sheet to five centimeters less than in competing makes of equipment. This yields correspondingly great reductions in energy consumption–an excellent example of the company’s technology leadership. The distance is also important with hot air: each additional centimeter means that the air is stirred up more readily and less of it reaches the sheet. The effects are even greater when drying with UV radiation: here each centimeter less translates into up to ten percent less power consumed. In its series for the large A1 format, Heidelberg has also turned the trick of bringing the dryer and sheet two centimeters closer together.

Additional energy savings can be expected with the aid of the new “DryingMonitor,” which was unveiled at this year’s drupa trade show in Düsseldorf for use with the Speedmaster XL105. Its sensors measure how much air carrying how much moisture flows into the dryer and out again. These two parameters can then be used to tell whether the sheet is really dry or not. For the first time, this gives the press operator a practical guide for controlling the drying process.

A very energy-efficient innovation also supports UVdrying: an electronic ballast helps maintain the arc of each UVlamp while it is in standby mode, while still reducing power consumption by between five and ten percent. This permits much more energy-efficient operation of the lamps than with conventional transformer technology. water instead of air cooling

To take advantage of waste heat, Heidelberg is also taking a new, energy-efficient approach that is unique in the industry: it is offering nearly all of its presses with water cooling instead of air cooling. Because water conducts heat very well, this type of system is considerably more efficient and cost-effective than conventional air cooling. Some Heidelberg customers are already using the waste heat stored in the cooling water, via heat exchangers, to heat single rooms or even an entire office building.

The second-biggest energy consumer in an offset printing press is the main drive motor, which eats up about one-quarter of the total power used. For technical reasons there is less latitude for realizing savings here, but Heidelberg has also found a way to make a difference: Its developers and engineers are incorporating “sine synchronous” motors that are two to three percent more efficient than conventional motors.

Heidelberg has also achieved significantly pared energy consumption for supplying presses with blast air, which is mainly needed for largely contactless sheet transport on air cushions. This accounts for about 20 percent of the total energy it takes to run a press. Fast-running, variable-speed turbo radial fans output the same amount of air while consuming up to 50 percent less power than earlier models. And because the supplied air is up to 30 degrees Celsius cooler, substantially less waste heat subsequently needs to be removed from the pressroom.

Adding up all of the improvements for saving energy, the power consumption of a Speedmaster XL105 can be cut by about 20 percent, or 120,000 kilowatt-hours, per year. This means that 62 metric tons less CO2is emitted into the atmosphere–as much as six hectares of deciduous forest can absorb in a year.

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